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Mycoflora and Aflatoxins in Soil, Eggshells, and Failed Eggs of Chelonia mydas at Ras Al-Jinz, Oman
Abstract
Eight genera and 14 species of fungi were isolated from soil and eggshells samples collected from the nesting site of the green sea turtle (Chelonia mydas) at Ras Al Jinz Reserve, Oman. The genus Aspergillus was the commonly represented, including 6 species: A. flavus, A. niger, A. terrus, A. nidulas, A. fumigatus, and A. ochraceus. Seventy-five percent of A. flavus strains isolated from eggshells were aflatoxigenic, producing aflatoxins in a concentration range of 0.3–28 ppb. The growth of fungi on turtle eggs and secretions of mycotoxins may affect embryonic development and possibly contribute to the green turtle egg mortality.
... For this reason, this isolate is considered here as a member of the FOSC, and it could correspond to F. oxysporum, or a closely related species ( Figure S1). Fusarium oxysporum has been repeatedly found in both nests and failed eggs of several sea turtles [75][76][77][78][79][80]. Additionally, its presence in Dermochelys coriacea eggs negatively affects the size of the hatchlings [81], which could have undesirable consequences on their survival. ...
... To our knowledge, R. microsporus has not been previously reported from reptiles. In contrast, its close relatives R. stolonifer and R. oryzae have been isolated from eggs and nests of green turtles, Chelonia mydas [75,78,88,89]. Rhizopus stolonifer has been also found in soft-shell turtles, Apalone ferox, affected by cutaneous mycosis [90]. ...
... Rhizopus stolonifer has been also found in soft-shell turtles, Apalone ferox, affected by cutaneous mycosis [90]. Interestingly, several members of the genus Rhizopus produce mycotoxins [75,91] that might be harmful for the turtle embryonic development, although this remains to be proved. As for Penicillium, some species of this genus have been identified in nests, eggs and skin lesions of numerous chelonians, including terrapins, tortoises and sea turtles [75,78,89,[92][93][94]. ...
The endangered yellow-spotted river turtle (Podocnemis unifilis) has experienced a dramatic population decline in the Ecuadorian Amazonia, mainly due to overexploitation of its eggs. To reverse this trend, the Wildlife Conservation Society has developed a head-start program in Yasuní National Park since 2008, but the potential risk that microbes associated with its eggs might represent for hatching success has not been evaluated yet. Members of the Fusarium solani species complex (FSSC) are involved in egg failure in sea turtles under natural and hatchery conditions, but their role in infecting the eggs of P. unifilis is unknown. In this study, we collected eggshells of P. unifilis and obtained 50 fungal and bacterial isolates. Some potentially pathogenic fungi of the genera Fusarium, Penicillium and Rhizopus were identified based on molecular data. Most importantly, the sea turtle pathogenic species F. keratoplasticum not only was present, but it was the most frequently found. Conversely, we have also isolated other microorganisms, such as Pseudomonas or Phoma-like species, producing a wide spectrum of antifungal compounds that may have a protective role against fungal diseases. Our survey provides useful information on potential pathogens found in P. unifilis eggshells, upon which the success of conservation programs may depend.
... These fungi were found growing on 29% and 4% of the failed and hatched eggs respectively. Fungal hyphae were found growing on the surface of failed eggs, inside the eggshells, and on the egg membranes (Elshafie et al. 2007). Although some isolates are known to be potential pathogens, the presence of these fungi does not necessarily lead to the development of disease. ...
... In fact, some species of Fusarium are known to produce a number of mycotoxins in culture, including fumonisins. If these toxins are produced in and on the surface of eggs they can affect embryo development (Elshafie et al. 2007). Elshafie et al. (2007) found aflatoxins in 40% of the eggshells studied at a concentration ranging between 4.1 and 8.4 ppb and in 25% of failed egg's contents at concentrations of 0.14-2.0 ...
... If these toxins are produced in and on the surface of eggs they can affect embryo development (Elshafie et al. 2007). Elshafie et al. (2007) found aflatoxins in 40% of the eggshells studied at a concentration ranging between 4.1 and 8.4 ppb and in 25% of failed egg's contents at concentrations of 0.14-2.0 ppb. ...
Sea turtles are presently considered severely endangered species that are historically threatened by many environmental factors. Recently, additional threats to sea turtles from two pathogenic species of fungi in the Fusarium solani species complex (F. falciforme and F. keratoplasticum) have been identified. These species infect marine turtle eggs, causing sea turtle egg fusariosis, and kill their embryos, with recent reports of hatch-failure in seven globally distributed species of endangered sea turtles (Caretta caretta, Chelonia mydas, Dermochelys coriaceae, Eretmochelys imbricata, Lepidochelys olivacea, Lepidochelys kempi and Natator depressus). Mycelia and spores of pathogenic species of Fusarium are produced in disturbed terrestrial soils and are transported to the ocean in coastal run off. We propose that these fungi grow on floating particles of plant tissues (leaves and wood), animal tissues, silt and plastics, which are carried by wind and currents and the turtles themselves to the beaches where the turtles lay their eggs.
... Most of the sea turtle populations have been declining due to human activities, predators, beach erosion, tidal inundation, plant root invasion, developmental abnormalities as well as pathogenic infections Hamann et al. 2010;Rees et al. 2016). Recent investigations are focused on the role some fungal pathogens play as a reason for decreasing hatching success during the embryonic development of some sea turtle species (Elshafie et al. 2007;Sarmiento-Ramirez et al. 2010Neves et al. 2015). ...
... Sea turtles use both terrestrial and marine habitats during their life cycle; however, the soft-shelled eggs cannot survive in water and must be laid on land. Thus, their eggs are exposed to many pathogenic fungi, which may impair nest success, either invasion of eggshell/failed eggs or by producing toxic compounds (Solomon and Baird 1980;Elshafie et al. 2007;Sarmiento-Ramirez et al. 2014 Keene 2012;Sarmiento-Ramirez et al. 2014). The objectives of this study were to determine which fungal isolates are associated with green turtle (Chelonia mydas) nests at Sugözü Beaches, amongst the most important nesting beaches for green turtles in the Mediterranean, as well as to examine phylogenetic relationships among these isolates. ...
... Evolutionary analyses were conducted in MEGA7 (Kumar et al. 2016) and Papenbrock 2015). Despite the detection of Aspergillus species from the sand samples and eggshells, mycotoxigenic species in nests could pose serious threats to embryonic development (Elshafie et al. 2007). These species can also affect egg hatching with mycotoxins or toxic metabolites that they negatively affect embryonic development without direct contact (Elshafie et al. 2007). ...
The aim of this study is to investigate the fungal diversity of green turtle nests and to examine phylogenetic relationships among these isolates. During the nesting season, samples of intra-nest sand and failed eggs were collected from 25% of the surviving nests in Sugözü Beaches, which are amongst the most important nesting beaches for endangered green turtles in the Mediterranean. Twenty-three fungi were identified by molecular techniques. Fungal isolates belonged to genera Aspergillus, Emericella, Rhizopus, Actinomucor and Apophysomyces with two undescribed species. Aspergillus variecolor, Aspergillus quadrilinieatus, Aspergillus tubingensis, Rhizopus oryzae, Actinomucor elegans and Apophysomyces variabilis were firstly detected in all sea turtle nests within this study. Our results demonstrate that 36.4% of the nests had fungal contamination. Also hatching success of the nests contaminated by fungi were significantly lower than the uncontaminated nests (P = 0.029). Also, this may represent a threat to marine turtles and a risk for the health of conservation workers. This study is the first molecular phylogenetic study associated with sea turtle nests in the eastern Mediterranean coast and contributes to the wider body of literature on fungal invasion of sea turtle nests with firstly isolated species. These findings are important for improving potential conservation measures for the nest sites.
... The most abundant genus was Aspergillus with 13 isolates distributed in 5 species (i.e., Aspergillus alliaceus, Aspergillus ochraceus, Aspergillus penicillioides, Aspergillus restrictus, Aspergillus terreus). The presence of these fungi represents a threat to nesting leatherback females because they have been previously reported causing loss of turtle eggs during incubation (Solomon and Baird 1980;Eckert and Eckert 1990;Phillot et al. 2001;Phillot and Parmenter 2001b;Elshafie et al. 2007). Penicillium and Fusarium are of special interest as well for their potential as egg pathogens. ...
... The fungus is well known as an opportunistic pathogen in immunocompromised humans and has also been reported causing serious infections in leatherback hatchlings and hyalohyphomycosis in loggerhead sea turtles (Cabañes et al. 1997;Miller et al. 2009). Other Fusarium species have been also isolated from sea turtle nests and eggs, including Fusarium moliniforme and F. oxysporum, also associated with the occurrence of bronchopneumonia in adult sea turtles (Phillot et al. 2001;Elshafie et al. 2007;Güclü et al. 2010). More recently Fusarium falciforme was documented as an emerging pathogen associated with hawksbill sea turtles hatched and unhatched eggs from Ecuador (Sarmiento-Ramírez et al. 2014). ...
... All of these fungi were isolated from nests sand and egg surface but were not able to colonize the eggs' interior. Aspergillus species have been reported as a threat to sea turtle clutches for their mycotoxigenic properties and has been the most frequent species isolated from sea turtle nests in other studies (Elshafie et al. 2007). Our Aspergillus isolates may then contribute to egg failure during incubation, not by direct colonization, but by the production of mycotoxins that could diffuse through the eggshell and negatively affect embryo development. ...
This work describes the mycelial fungal diversity associated with leatherback sea turtle nests and eggs from Mayagüez-Añasco Bay Coast (MABC), Puerto Rico. Comparisons are made of conditions previous to leatherback nesting season, during leatherback nesting season, and during nest hatching season. Prior to Dermochelys coriacea nesting season, the fungal community along the MABC showed a normal distribution (p = 0.098) by One-Way ANOVA. We found that Aspergillus was the most frequent genus (0.15), followed by Cladosporium (0.09) and Curvularia (0.08). At the time of oviposition, Penicillium was the most frequent isolate (0.15), followed by Cladosporium (0.11), Aspergillus (0.11), and Fusarium (0.07). No fungi were isolated from nesting leatherback's ovipositor samples. During hatching season, fungal diversity was evaluated from the sand of hatched nests and from failed eggs. Fusarium solani was the most frequent isolate (0.57) from hatched nest sand and was the only species isolated from the interior of failed eggs. A strong positive correlation was obtained between fungal abundance and the number of failed eggs in the nests (r = 0.853, p < 0.001). This was the first attempt to study fungal diversity associated with D. coriacea nests and eggs in Puerto Rico.
... Many pathogenic infections are not fatal but can influence the fitness of the host, which in turn can have consequences on the species' population dynamics (Dighton, 2003). Fungi-host relationships have been studied in eggs of sea turtles (Phillot et al., 2004;Elshafie et al., 2007;Güçlü et al., 2010), amphibians (e.g., Baláž et al., 2012;Gower et al., 2012), lizards (Moreira Lopes & Barata, 2005), snakes (Paré et al., 2003) and crocodiles (Buenviaje et al., 1994;Thomas et al., 2002). Oviparous female reptiles often deposit clutches in close proximity to each other (Pianka & Vitt, 2003). ...
... It is possible that soil-growing fungi contaminated the eggs when they were laid and/or during passage through the cloaca (Phillot et al., , 2006Elshafie et al., 2007;Nuñez Otaño et al., 2013). Biotrophic-saprotroph fungi were abundant on egg shells and egg membranes, in line with the fact that they for example represent an estimated of 78-90% of the total microbial biomass of descomposing grassland (Frankland, 1982). ...
... can grow at different temperatures and substrates, and produce aflatoxins as secondary metabolite. Aspergillus niger has been isolated from Chelonias mydas eggs (Elshafie et al., 2007) and in the cloaca of the C. latirostris . Aspergillus fumigatus has also been isolated from partially decomposed vegetation from in nests of C. crocodylus fuscus (Tansey, 1973), and can have lethal effects on eggs, hatchlings and young caimans (Palacios & Sick, 2004). ...
Studies describing and identifying mycobiota affecting the eggs of wild reptiles are rare, despite the potential importance of mycoses for the survival and performance of individuals and populations. The aim of this study was to identify the fungal species on eggshell and eggshell membranes of C. latirostris and to discover potential compositional changes between these two substrates. Twenty-four species of fungi were isolated from eggshells and 17 species were isolated from membranes; 10 species were shared between both substrates. Saprophytic fungi comprised 64.1% of eggshell and 59.4% of eggshell membranes mycobiota, respectively. Potentially pathogenic fungi occurred more frequently on the eggshell membrane (71.4%). From pathogenic assays we cannot conclude that fungi like Aspergillus fumigatus and Fusarium oxysporum have a negative effect on hatching success, weight and snout-vent length of C. latirostris hatchlings.
... In this study, Fusarium species were not detected in sand samples of all nests, even though they contained Fusarium-colonised eggs, which is also consistent with a previous study in Melaka by Sidique et al. (2017). Elshafie et al. (2007) and Neves et al. (2015) also isolated fungi from the sea turtle eggs but not from the corresponding sand samples. Some studies implicated that the source of Fusarium infection was the nesting sand because only eggs in contact with the sand were infected, while Fusarium species is also common as a soil saprophyte Sarmiento-Ramírez et al., 2014). ...
... Nevertheless, the mycotoxins of another fungal species called Aspergillus flavus are extracted from the eggshells and eggs of dead sea turtles eggs. The level of mycotoxins was believed to be able to cause embryonic mortality (Elshafie et al., 2007). Sarmiento-Ramírez et al. (2010) conducted pathogenicity tests on loggerhead turtle eggs with isolates from the member of the FSSC called F. keratoplasticum through inoculation challenge experiments. ...
Hatching failure is one of the threats to the declining sea turtle population. Sea turtle egg fusariosis, an emerging fungal disease, has been linked to lower hatching success in sea turtle nests. The disease is associated with the presence of members of the (Fusarium solani species complex (FSSC). Samples of cloacal mucus, nest sand, eggshells, and eggs were collected from seven hawksbill turtles and their corresponding nests at Melaka’s nesting beaches and hatchery site. FSSC was prevalent in the unhatched eggs (n = 32) from the seven study nests, colonising 96.9%. The remaining eggs from the study nests were found to have high hatching success, with a mean of 85.8 ± 10.5% (n = 7). It is unknown if the presence of FSSC contributed directly to embryonic mortality in this study. There are two possible roles of FSSC in sea turtle eggs: as a saprophyte or a primary pathogen. The presence of FSSC in the nest did not always compromise the hatching success of the entire egg clutch. FSSC was not detected in the sand samples of all nests, even though all nests contained Fusarium-colonised eggs. The concentration of FSSC in the sand might influence the infection rate of sea turtle eggs and their hatching success. Best practices for hatchery must be in place to achieve high hatching success for sea turtle conservation.
... Fusarium sp dan Aspergillus sp merupakan jamur yang menghasilkan senyawa mycotoxic yang mengganggu perkembangan embrio sehingga berkontribusi terhadap kegagalan telur penyu menetas. Jamur yang berkembang pada telur penyu mempengaruhi embrio denngan tiga cara antara lain: (1) menghambat pertukaran gas pada embrio, (2) penipisan kalsium pada cangkang telur sehingga mempengaruhi perkembangan embrio, (3) transfer spora jamur dari allantois ke jaringan embrio (Elshafie, et al, 2007). Penghambatan pertukaran gas oleh jamur dilakukan dengan menutup pori-pori kulit sehingg menyebabkan kematian. ...
... Mallo, et al. (2002), melaporkan bahwa Aspergillus sp telah diisolasi dari lesi kulit dan mikosis superfisial dari penyu tempayan. Spesies Aspergillus terutama A. flavus, A. niger, A. terreus, A. nidulas, A. fumigatus, dan A. ochraceus juga terisolasi dari telur gagal menetas pada penyu hijau, dan jamur tersebut memproduksi mikotoksin pada telur dan penyu yang akan mempengaruhi embrio dan berkontribusi terhadap kematian penyu (Elshafie et al., 2007). ...
Penyu merupakan vertebrata laut yang termasuk kedalam kategori Appendix 1 yang artinya dilarang diperdagangkan secara internasional. Selain itu penyu salah satu hewan yang paling terancam populasinya secara langsung maupun tidak langsung. Kematian tukik penyu disebabkan oleh berbagai faktor, diantaranya kerusakan habitat alami, pencemaran laut, serangan predator dan perburuan daging maupun telurnya untuk kepentingan komersial. Selain itu, menurunnya jumlah populasi penyu juga disebabkan dari infeksi jamur. Adanya jamur juga menjadi masalah di TCEC (Turtle Conservation and Education Center) yang menyebabkan tingginya tingkat kematian tukik dari penyu lekang (Lepidochelys olivacea). Maka dari itu dengan mengetahui jenis jamur yang ditemukan dapat dilakukan pengobatan serta pencegahan sesuai jamur yang menginfeksi. Tujuan dari penelitian ini adalah untuk mengidentifikasi jamur yang ditemukan pada bagian tubuh penyu lekang (L. olivacea) dan cangkang telur penyu gagal menetas. Sampel tukik dari penyu lekang berumur 10 – 14 hari didapatkan dari penangkaran penyu TCEC Bali. Sampel yang sudah diambil kemudian diswab pada media PDA dan diinkubasi selama 7 hari. Setelah itu dilakukan purifikasi hingga didapatkan koloni murni. Tahap selanjutnya yaitu dilakukannya identifikasi genus secara makroskopis dan mikroskopis pada perbesaran 40x dan 100x. Hasil penelitian memperlihatkan bahwa dari 10 sampel jamur yang diambil dari beberapa bagian tubuh penyu seperti pada mata, kaki, leher dan karapas dan cangkang telur gagal menetas saat sampling, didapatkan 15 isolat koloni jamur. Dari 15 isolat tersebut, ditemukan 5 genus Aspergillus sp, 5 genus Fusarium sp, 3 genus Pytophthora sp dan 1 isolat Trichoderma sp. Pada bagian tubuh jamur yang paling banyak ditemukan yaitu pada bagian leher sebanyak 4 koloni dan masing-masing jenis jamur bisa ditemukan pada bagian leher. Jenis jamur yang paling banyak ditemukan pada cangkang telur penyu lekang yang gagal menetas yaitu jamur Aspergillus sp yang masing – masing memiliki bercak kuning pada cangkang telur. Selain dari cangkang telur yang memiliki bercak kuning didapatkan juga dari cangkang telur yang melunak. Turtle is a marine vertebrata that belongs to Appendix 1 category which means it is prohibited to be traded internationally. In addition there is a sea turtle one of animals that are most under threat its population is set directly or indirectly. The death of hatchlings sea turtle was caused by various factors, including natural habitat destruction, marine pollution, predatory attacks and the hunting of meat and eggs for commercial purposes. In addition, the declining number of turtle populations is also caused by fungal infections. The presence of fungi is also a problem in TCEC which causes high mortality rates of turtles (Lepidochelys olivacea). Therefore, by knowing the type of fungus that can be found to be treated as well as prevention of appropriate fungi that infect. The purpose of this study was to identify the fungus found in the turtle body part (L. olivacea) and the turtle eggshell failed to hatch. The turtle samples from turtles aged 10-14 days were obtained from TCEC Bali turtle breeding. Samples were taken later in swabbing on PDA media and incubated for 7 days. After that purification to get a pure colony. The next stage is the identification of the genus in macroscopic and microscopic at 40x and 100x magnification. The results showed that from 10 samples of fungus taken from some parts of sea turtle body such as on eyes, feet, neck and carapace, and eggshell failed to hatch during sampling, 15 isolates of fungal colonies were found. Of the 15 isolates, found 5 genera of Aspergillus sp, 5 genus of Fusarium sp, 3 genus of Pytophthora sp and 1 isolate of Trichoderma sp. In the body of the fungus is most commonly found in the neck as much as 4 colonies and each type of fungus can be found on the neck. The most common types of fungus found in eggshell shells that fail to hatch are the Aspergillus sp fungus, each of which has yellow spots on the eggshell. Apart from the eggshell that has yellow spots it is also obtained from the softened eggshell.
... There are some studies reporting that F. falciforme and F. keratoplasticum are identified as pathogens in nests and cause high rates of embryonic deaths (Sidique et al. 2017). Moreover, in a study on Ch. mydas nests in Oman, these species were isolated from the eggs and some strains produced mycotoxins (Elshafie et al. 2007). From the results of the present study, it is considered that the hatching success in Iztuzu Beach in the 2016 season was negatively affected by the increase occurred in the percentage of F. oxysporum. ...
... In addition, infection rates are high in the nests that occur between the seasons and have low success percentage. Therefore, this stress on the eggs is considered to be due to the toxic activity on the immune system and protein synthesis inhibitor effect caused by these aggressive fungi species (Elshafie et al. 2007;Gleason et al. 2020). However, when both nesting seasons were taken into account, this situation reduces the likelihood of a major threat to hatching success, as it is considered in the study performed on Jekyll Island (Bailey et al. 2018). ...
There are various biotic factors affecting the hatching success of loggerhead sea turtles (Caretta caretta) nesting on Mediterranean beaches. Eggs contaminated by fungi and bacteria are adversely affected in terms of hatching success. This study aims to identify Fusarium species that cause infection by sampling eggs and nest sands that failed to hatch during the 2015–2016 nesting season. Biospeedy fungal diversity kit was used to identify Fusarium species. Fungi were isolated from eggs and nest sands F. solani, F. oxysporum, F. falciforme and F. keratoplasticum were isolated from nest sand, and F. solani, F. oxysporum were isolated from egg contents. Fusarium species were determined for the first time using molecular methods for Turkey. Fusarium solani (54.55%) was observed to be dominant and F. oxysporum (40.91%) subdominant species. In addition to these dominant species, F. falciforme (1.82%) and F. keratoplasticum (2.73%) have been the other isolated species. The hatching success of the nests contaminated with Fusarium spp. was found to be 10.6% lower than in non-infected ones. Although there was no significant difference between the percentage of hatchling success in infected and non-infected nests in the 2015 season (n = 20) where the number of nests used in sampling was low, a significant difference was found between the success rates in the 2016 season (n = 41) where the number of nests used in sampling was higher (p = 0.676, p = 0.028, respectively). Nest temperature, depth and distance from the sea were higher infection rate, whereas relative humidity was lower in infected nests than in non-infected nests (p < 0.05 for all). Identifying the Fusarium species, which pose serious risks for sea turtle nests worldwide, and investigating their effects on hatching success became more of an issue. In this study, the determination of Fusarium species contaminating the eggs in Iztuzu Beach (Muğla, Turkey) and their sequence analysis was conducted for the first time.
... Many thanks to the volunteers at the Pretoma sea turtle camp at Playa Caletas who helped with field data collection, the MTN reviewers, E. Whitman for earlier reviews of the manuscript, and R. Lewison at San Diego State University for issuing undergraduate biology credit for this internship. Microbes (bacteria and fungi) have been isolated from the exterior and/or contents of unhatched sea turtle eggs (Acuña-Mesén 1992; Bustard & Greenham 1968;Chan & Solomon 1989;Eckert & Eckert 1990;Elshafie et al. 2007;Mo et al. 1990;Peters et al. 1994;Phillott et al. 2001;Ragotzkie 1959;Solomon & Baird 1980;Solomon & Tippett 1987;Whitmore & Dutton 1985;Wyneken et al. 1988), and implicated in egg failure (Eckert & Eckert 1990;Elshafie et al. 2007;Phillott & Parmenter 2001b;Solomon & Baird 1980;Solomon & Tippett 1987;Wyneken et al. 1988). Fungi are known to utilize a failed egg as a nutrient focus, and hyphae spread throughout the nest to adjacent viable eggs (Phillott & Parmenter 2001b), but the etiology of bacterial presence in the nest has not been described. ...
... Many thanks to the volunteers at the Pretoma sea turtle camp at Playa Caletas who helped with field data collection, the MTN reviewers, E. Whitman for earlier reviews of the manuscript, and R. Lewison at San Diego State University for issuing undergraduate biology credit for this internship. Microbes (bacteria and fungi) have been isolated from the exterior and/or contents of unhatched sea turtle eggs (Acuña-Mesén 1992; Bustard & Greenham 1968;Chan & Solomon 1989;Eckert & Eckert 1990;Elshafie et al. 2007;Mo et al. 1990;Peters et al. 1994;Phillott et al. 2001;Ragotzkie 1959;Solomon & Baird 1980;Solomon & Tippett 1987;Whitmore & Dutton 1985;Wyneken et al. 1988), and implicated in egg failure (Eckert & Eckert 1990;Elshafie et al. 2007;Phillott & Parmenter 2001b;Solomon & Baird 1980;Solomon & Tippett 1987;Wyneken et al. 1988). Fungi are known to utilize a failed egg as a nutrient focus, and hyphae spread throughout the nest to adjacent viable eggs (Phillott & Parmenter 2001b), but the etiology of bacterial presence in the nest has not been described. ...
Conservation Recommendations. This study demonstrated how
a desolate sea turtle beach can be affected by man-made debris,
mostly plastics. We found an alarmingly high density of garbage
(0.14 pieces per m2), which is similar to densities in heavily
populated/tourist areas like Armação dos Búzios, a beach near Rio
De Janeiro, Brazil (0.14 pieces per m2) (Oigman-Pszczol & Creed
2007). The large amount of trash at Playa Caletas has the potential
to affect sea turtles by causing entanglement of nesting females,
blocking nesting areas, increasing sand compaction, entangling
emerging hatchlings, and blocking/entangling hatchlings from
reaching the sea. If solid waste is blown or washed out to sea
it may also become ingested and/or cause further entanglement
(Bugoni et al. 2001; Carr 1987; Wabnitz & Nichols 2010).
We recommend involving local community members as much
as possible in sea turtle and garbage surveys and cleanups for both
educational purposes and to increase support for the continuation of
the programs. Apart from the opportunity for extensive sampling,
community participation in beach cleanups has been considered an
important strategy of increasing public awareness and motivating
community action (Bravo et al. 2009; Marcovaldi & Marcovaldi
1999). Costa Rica in particular, with an economy that depends
on eco-tourism, and a local population that is environmentally conscious
and educated, could become a pioneer in developing
solutions to the plastic problem.
... Specifically, F. solani was isolated from the shell of unhatched eggs of nest 1 and the shell of hatched eggs of nest 2, while F. falciforme was present in the internal content of unhatched eggs of nest 1 and the shell of unhatched eggs of nest 2. Although Fusarium was not found inside the eggs of nest 2, its effect on egg development and hatchings could occur without direct contact with the eggs. In fact, some species of Fusarium are known to produce volatile mycotoxins or other metabolites that affect adjacent eggs influencing embryo development [34,35]. Our results strongly suggest that Fusarium spp. ...
Microbial communities provide essential information about host ecology and could be helpful as a tool to improve species conservation efforts. However, microbes can also infect and compromise the host development process and viability. Caretta caretta is the most widespread marine turtle species in the Mediterranean basin and is the only species of sea turtle nesting along the Italian coasts. Little is known about the microbiota composition of the nest of sea turtles and its correlation with hatching failures. In this study, the microbial composition of two nests of C. caretta featuring different rates of hatching success from a nesting beach in Lampedusa (Italy) was analyzed and compared. The bacterial community was determined using culture-dependent methods and next-generation sequencing based on 16S rRNA gene metabarcoding analysis. Our results showed five dominant bacterial phyla (Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, and Firmicutes) and indicated different bacterial families (Pseudomonadaceae and Brucellaceae) as likely causes of hatching failures. Besides, our findings demonstrated the nests’ active role in modulating the sand’s bacterial communities. This study suggests microbiological analysis could be a valuable tool in monitoring nests to take preventive actions and reduce hatching failures.
... It is possible that the volcanic substrate composition itself may cause dehydration, leading to the death of the embryos (Marco et al., 2017). The mechanism responsible for this lower hatching success and the association with biotic factors linked to each substrate, e.g., microflora, is still under study for sea turtles (Elshafie et al., 2007). ...
We conducted a 5-year field (2017–2021) and laboratory study of the relationship between type of substrate and hatching success, embryonic development, and the quality of hatchlings in loggerhead turtle nests. Our study site, the island of Maio in the archipelago of Cabo Verde, one of the world’s largest loggerhead turtle nesting colonies, displays marked heterogeneity of sand colouration, with dark, mixed, and light sandy beaches. We experimentally incubated eggs, comparing different nesting substrates under standard temperature and humidity conditions. Females nest in all sand types without preference. However, both the field and experimental study revealed a significant difference in hatching success depending on the type of substrate. Substrate of volcanic origin, dark in colour, with a lower amount of calcium carbonate, had a lower hatching success (HS; 30.3 ± 20.2%) compared to substrates of mixed (HS = 46.1 ± 26.5%) or light (HS = 78.1 ± 18.2%) colour. Eggs experimentally incubated in substrate that was light-coloured, with a larger grain size and higher calcium carbonate concentration, produced significantly more and larger offspring. Incubation temperatures were significantly higher in dark substrate, which partially explains the lower hatching success in this type of sand. However, experimental incubation with controlled temperatures consistently showed lower hatching success in dark sand. Thus, we found that not only the temperature, but also the specific characteristics of each substrate determine hatching success. The main predator of eggs and hatchlings (the ghost crab Ocypode cursor) showed no significant differences in abundance or size between different substrate types. Our results indicate that nest site selection between beaches or even within the same beach with different substrate conditions affects hatching success, hatchling physical condition, and subsequently the reproductive success of each female. The results of this study can inform conservation programmes with nest management and controlled incubation in the field and optimise adaptive nest management under future scenarios of rising global temperatures.
... Though Fusarium is believed to be the most relevant fungal pathogen to sea turtle egg mortality, other species of fungi have also been isolated from diseased turtles and failed sea turtle eggs collected in natural rookeries, including Paecilomyces sp. that can cause pneumonia in C. mydas (Glazebrook and Campbell, 1990) and Colletotrichum acutatum that can infect the lungs and kidneys of Lepidochylys kempi (Manire et al., 2002). The Sordariomycetes Pseudallescheria boydii has been isolated from failed eggs of the turtles C. caretta, C. mydas, E. imbricata, and N. depressus in Australia (Phillott and Parmenter, 2001;Phillott et al., 2004), while unidentified Aspergillus, Eurotium, and Cladosporium cladosporioides are regularly isolated from hatched egg shells of C. mydas and E. imbricata (Elshafie et al., 2007;Neves et al., 2015;Gleason et al., 2020). The virulence of these co-occurring fungi generally remains to be elucidated. ...
Fungi cause diseases in a variety of marine animal hosts. After a thorough review of published literature, we identified 225 fungal species causing infections of 193 animal species, for a total of 357 combinations of pathogenic fungi and marine animal hosts. Among the 193 animal host species, Chordata (100 species, 51.8 %) and Arthropoda (68 species, 35.2 %) were discovered to be the most frequently reported hosts of fungal pathogens. Microsporidia (111 species, 49.3 %) constitutes over half of the described pathogenic fungal species of marine animals, followed by Ascomycota (85 species, 37.8 %), Mucoromycota (22 species, 9.8 %), Basidiomycota (6 species, 2.7 %) and Chytridiomycota (1 species, 0.4 %). Microsporidia primarily parasitize marine arthropods and Teleostei fish, while Basidiomycota are primarily known to cause respiratory diseases of marine mammals. Ascomycota has a diverse host range, from mammals, fish, crustaceans, soft corals and sea turtle. Few Mucoromycota and Chytridiomycota were reported to infect marine animals. Fungal diseases documented in this review likely represent a fraction of fungal diseases in the ocean, where it was estimated to be inhabited by 2.15 million animal species. Intensification of aquaculture practices, global warming and marine pollution may increase fungal disease outbreak of marine animals. All the topics mentioned above will be discussed in greater details in this review.
... Fungi have previously been isolated from the eggs of sea turtles such as Fusarium solani, Pseudallescheria boydii, Fusarium oxysporum, and several Aspergillus spp. (Phillott et al., 2001;Elshafie et al., 2007;Sarmiento-Ramírez et al., 2010). Of these, the most frequently isolated and studied species are Fusarium falciforme and Fusarium keratoplasticum, which belong to the Fusarium solani species complex (FSSC; O'Donnell et al., 2008). ...
Hatchery practices are pivotal to conservation success. In sea turtle hatcheries, reusing sand is a norm, but it remains unclear whether such an approach increases the risk of Fusarium solani species complex (FSSC) infection and mortality in sea turtle eggs. We employed 16S and ITS amplicon sequencing in sands and isolated Fusarium strains from diseased eggs across seven turtle hatcheries and their neighbouring beaches in Malaysia. FSSC was isolated from all sampled hatcheries, and Fusarium falciforme was the predominant species (82.9%). All but one hatchery had a distinct microbiota and higher abundance of FSSC (mean = 5.2%) than the nesting beaches (mean = 1.3%). The hatchery that maintained the most stringent practice by not reusing sand had a microbiota resembling that of nesting beaches, and the lowest FSSC abundance. The results of the current study imply that sand should not be reused in sea turtle hatcheries.
... Detection of other fungal types here was limited to a single egg (Table 1). This included Aspergillus and Penicillium; members have been previously cultivated from sea turtle eggs and certain strains produce mycotoxins (Elshafie et al. 2007, Güçlü et al. 2010). However, the low incidence implies that these groups are unlikely to pose a major threat to hatching success on Jekyll Island. ...
The recognition of the Fusarium solani species complex (FSSC) as a potential global threat to sea turtle eggs represents yet another instance of an emerging fungal infection impacting wildlife. Traditionally, culturing has been used to identify fungi associated with sea turtle eggs. Since culturing recovers only a subset of environmental microbes, a molecular approach was adopted instead to survey the fungal composition inside unhatched eggs. DNA was directly extracted from the embryonic fluid and biofilms in 73 fully incubated unhatched loggerhead sea turtle eggs collected from different regions of Jekyll Island, GA, USA, in 2010 and 2012. The fungal internal transcribed spacer region of the nuclear ribosomal DNA (ITS nrDNA) was amplified from the DNA samples, and ITS products were cloned, sequenced and subjected to phylogenetic analysis. Sequences corresponded to previously cultivated fungi and were dominated by the FSSC members Fusarium falciforme and F. keratoplasticum. These fungi were consistently de - tected in unhatched eggs throughout Jekyll Island during each nesting year examined. Fusarium falciforme and F. keratoplasticum ITS sequences were nearly identical to isolates implicated in causing disease in sea turtle embryos from Ascension Island, Australia, Central America and Cape Verde. This represents the first survey establishing these fungal groups in North American loggerhead eggs and provides confirmation of the widespread distribution of F. falciforme and F. keratoplasticum using a novel approach. As we begin to meet conservation goals of species recovery, density-dependent management issues such as emerging fungal infections become a growing concern. Assessing the long-term impacts of Fusarium may be a rising priority.
... Eighty-five unhatched eggs of green and hawksbill turtles showed bluish discolorations ( Figure 2) similar to those reported by Sarmiento-Ramírez et al. (2010) at Boavista Island, Cape Verde. Fungal growth can occur on the external surface of unhatched turtle eggs and the internal shell membrane and embryonic tissue, as reported by Elshafie et al. (2007) and Sarmiento-Ramírez et al. (2010). Sarmiento-Ramírez et al. (2010) had performed Koch's postulates on F. solani and after 6 days of inoculation, the healthy eggs showed similar symptoms to those in the field and the mortality rate was 83.7%. ...
In recent years, turtle eggs incubated in situ or in protected hatcheries in Malaysia have been reported to show symptoms and signs of fungal colonisation. However, there are no studies addressing this problem and potential relationship with frequent hatching failures. We identified Fusarium species from nesting sites of green turtle (Chelonia mydas) and hawksbill turtle (Eretmochelys imbricata) situated in Terengganu and Melaka, as well as the environments surrounding those sites. The eggs were incubated on the nesting beach (in situ) or relocated to the beach hatchery and styrofoam boxes (ex situ) in Peninsular Malaysia. Samples were collected from infected eggs, sand, plant roots and debris around the egg chambers. One-hundred and six strains of Fusarium spp. were isolated. They were identified morphologically as member of the Fusarium solani species complex (FSSC, 101 strains), F. oxysporum (four strains) and F. proliferatum (one strain). We conducted phylogenetic analysis based on nucleotide sequences of translation elongation factor 1-alpha gene (TEF-1α). The strains of the FSSC were further separated into three lineages, F. falciforme, F. lichenicola and F. keratoplasticum. This is the first report on Fusarium species isolated from symptomatic green and hawksbill turtle eggs in Peninsular Malaysia. Fusarium colonisation in sea turtle nests poses a serious risk to the survival of endangered sea turtles in Malaysia. It is, therefore, important to examine the nature of such colonisation and their relationship to hatching failures of the turtles in Malaysia or elsewhere in the region to mitigate pathogenic fungi impact. © 2017, Malaysian Society of Applied Biology. All rights reserved.
... In addition, some of the detected fungi, e.g. Aspergillus niger, have been reported as producers of mycotoxins that can affect humans (Elshafie et al., 2007;Nielsen et al., 2009). ...
The study analyzed fungal diversity in soil trapped behind dams in three arid regions of Oman, in the south-eastern part of the Arabian Peninsula. Physicochemical analysis indicated that soils are of the loamy sand or sandy loam types and they are deficit in some macro and micro elements. Culture-based techniques revealed variation between dam soils in the number and type of phyla, classes, orders, genera and species. Ascomycota was the most dominant phyla in the three samples, contributing to 89% of the total species. Eurotiomycetes, Sordariomycetes and Dothideomycetes were the most common classes in dam soils. Zygomycetes, Pezizomycetes and Oomycetes were also detected, but at lower levels. Fifty fungal taxa were recovered from the three dam soils, with Aspergillus, Penicillium and Trichoderma being the most common genera. Most of the detected species were saprophytes; however some were either plant pathogens or mycotoxin producers, affecting humans directly or indirectly. This study appears to report for the first time 20 fungal species in Oman. It is also the first study from arid regions to characterize high fungal diversity in soil trapped behind dams. The sources of these fungi in dam soils and the implications of fungal diversity are discussed.
... The fungal communities adapted to these environments are therefore likely to be unique. Eight genera and 14 species were isolated from sand and eggshell samples collected from green sea turtle (Chelonia mydas) at Ras Al Jinz Reserve (Elshafie et al. 2007a). Most of these taxa were saprobes on soil and Aspergillus was the dominant genus. ...
Mycologists and plant pathologists have long been documenting fungi in checklists or adding them to databases that list hosts and associated fungi. Most references to the fungi of Oman are scattered in journals, reports and university theses. A review of the fungal status of Oman is long overdue as soil-borne and plant pathogens have been studied to some extent. Although Waller & Bridge (1978) listed the fungal diseases on economically important crops in Oman, the present study is the first attempt to put together all hitherto recorded fungi from this part of the world. This paper presents a systematic checklist of 318 fungal species, in 173 genera, currently known to occur in Oman. A working checklist of accepted taxa in Oman is vital in progress of the systematics, agriculture, quarantine and many other applied scientific fields in the country.
... Colletotrichum acutatum was identified as the causative agent in the death of a young specimen of Lepidochelys kempii in Florida in 2000 (Manire et al., 2002), emphasizing that the immune statuses of animals will determine their pathogen resis-tance. Elshafie et al. (2007) reported 14 species of fungi isolated from soil and eggs in C. mydas nests, with high incidence of Aspergillus species, especially: A. flavus, A. niger, A. terreus, A. nidulas, A. fumigatus, and A. ochraceus. Among these, A. flavus, A. niger and A. terreus were likewise isolated from the soil on the beaches at Merepe and Cupe (Ipojuca-PE), and it appears that fungal growth on eggs and on the sea turtles themselves, and the production of mycotoxins, will affect embryonic development and contribute to chelonian mortality. ...
Eretmochelys imbricata Linneus 1766 was the subject of trade due to egg collection and consumption of the flesh of the females, being the fishery one of the main impacts towards the coastal area. The pathogens are also worrying factors of mortality of sea turtles especially those caused by fungi; these can cause the death of embryos and cutaneous mycoses. This study aimed to investigate the mycoflora isolated from soil, eggshells and stillbirths from E. imbricata in three beaches of Ipojuca (Brazil). We recorded data on the reproductive biology of the species after incubation of nests. Soil samples and fragments of eggshells were collected at the end of the nesting season for fungi identification. A total of eight species of fungi were identified by their morphological characteristics: Aspergillus terreus, Aspergillus niger, Aspergillus flavus, Cladosporium cladosporioides, Nigrospora grisea, Fusarium solani, Fusarium lateritium and F. oxysporum in the soil samples, eggshells and stillbirths. Fusarium was recorded in other studies interfering with the development of turtles embryos. The data from this study will provide information to support the management and conservation of sea turtles.
... fungi are present in reptile eggs in general ( Moreira and Barata, 2005), as well as in those of sea turtles in particular ( Sarmiento-Ramírez et al., 2010). The majority of studies considering the ''fungus-egg'' relationship in sea turtles have taken place in Loggerhead (Caretta caretta) ( Guclu et al., 2010;Sarmiento-Ramírez et al., 2010), Green (Chelonia mydas) ( Phillott, 2004;Elshafie et al., 2007), Hawksbill (Eretmochelys imbricata) ( Phillott et al., 2004), and Flatback (Natator depressus) sea turtles ( Phillott and Parmenter, 2001b;). However, there has been less research in leatherback turtles, despite being one of the factors that could potentially contribute to the notably low hatching success of this species ( Whitmore and Dutton, '85;Bell et al., 2004). ...
Many conservation programs consider translocation of turtle nests to hatcheries as a useful technique. The repeated use of the same incubation substrate over several seasons in these hatcheries could, however, be harmful to embryos if pathogens were able to accumulate or if the physical and chemical characteristics of the incubation environment were altered. However, this hypothesis has yet to be tested. We conducted two field experiments to evaluate the effects of hatchery sand and eggshell decay on the embryonic development of leatherback sea turtle eggs in Colombia. We identified the presence of both fungi and bacteria species on leatherback turtle eggs. Sea turtle eggs exposed to previously used hatchery substrates or to decaying eggshells during the first and middle third of the embryonic development produced hatchlings that were smaller and/or weighed less than control eggs. However, this did not negatively influence hatching success. The final third of embryonic development seems to be less susceptible to infection by microorganisms associated with decaying shells. We discuss the mechanisms that could be affecting sea turtle egg development when in contact with fungi. Further studies should seek to understand the infection process and the stages of development in which the fungi are more virulent to the eggs of this critically endangered species.
A total of 60 green turtle eggs were obtained from sampling sites in Terengganu and Sabah, Malaysia. Isolation and identification of bacteria from these eggs resulted in 12 genera of Gram-negative bacteria with 12 different species. The most frequently isolated bacteria were Salmonella (30.9%) and Proteus (23.7%). The rest of the microorganisms were Aeromonas, Escherichia, Citrobacter, Enterobacter, Klebsiella, Morganella, Pseudomonas, Shigella, Serratia and Photobacterium. A slight difference in total crude protein content was recorded in the samples from Terengganu and Sabah, at 16.3% Dry matter (DM) and 15.8% DM, respectively. Meanwhile, the crude fat content found in the samples from Terengganu was 9.88% DM and 7.79% DM from Sabah. In this study, α-linolenic acid, C18:3 n-3 (Terengganu: 16.87% DM) and linoleic acid, C18:2 n-6 (Sabah: 15.19% DM) were the most prevalent fatty acids in both samples. The green turtle egg samples from Terengganu showed higher value of total saturated fatty acid, total C18:3 n-3 and C18:2 n-6 and total polyunsaturated fatty acids as compared to green turtle eggs from Sabah. The results also revealed that majority of the essential amino acids (EAA) recorded in samples from both sampling sites was lysine (9.67% DM), with higher value recorded in green turtle egg from Terengganu. However, there were no significant differences ( p >0.05) in the nutritional compositions, fatty acid contents and amino acid compositions of the samples between the two sampling sites. Meanwhile, statistical analysis showed significant differences in heavy metal concentrations between the two sampling sites for all the six heavy metals detected in this study (Hg, Cd, Pb, Mn, Zn and Cu). The ranking of heavy metals concentration in turtle eggs from both sampling sites, in decreasing order is as follows: Zn > Cu > Mn > Pb > Cd > Hg. Overall, these results reveal the contents and contaminations of a green turtle egg, which may raise concern on public health risks. Findings from this study will also be beneficial for the future conservation of green turtle population when the consumption of their eggs should be stopped.
Aflatoxins are secondary metabolites produced by specific strains of fungi, especially Aspergillus spp. These natural toxins are mainly found in soil, decaying vegetation and food storage systems and are particularly abundant during drought stress. Aflatoxin contamination is one of the most important threats to food safety and human health due to its toxic, mutagenic and carcinogenic properties. Therefore, most research focuses on post-harvest contamination of aflatoxins in feed and food commodities but very limited information is available about aflatoxin contamination and its toxicological consequences in the soil ecosystem. Current regulations provide minimal options for the disposal of aflatoxin-contaminated crops, amongst which is the incorporation of residues into the soil for natural degradation. This form of mycotoxin loading into the soil could potentially change its physicochemical characteristics and biotic parameters. Recent studies suggest that as climate conditions change, the occurrence and geographical distribution of aflatoxins might increase, posing significant health risks to the soil ecosystem, food crop production and human health. This review will focus on studies that look at the environmental and toxicological consequences of aflatoxin contamination with the aim of clarifying the risk that aflatoxin contamination poses to soil ecosystems. Many aspects of aflatoxin occurrence, degradation and the effects of its transformation products in the soil environment are still unknown and remain an important area of research for soil health and productivity. A climatic approach, in terms of changes in soil moisture and air temperature, is important for future risk assessments of aflatoxin contamination.
Tujuan dari penelitian ini adalah untuk mendeteksi adanya jamur pada sarang semi alami penyu lekang di Taman Nasional Meru Betiri Banyuwangi. Sebanyak 1 gram pasir pada 22 sarang penyu hijau digunakan sebagai sampel. Isolasi dan identifikasi dilakukan dengan pengamatan karakteristik makroskopis dari pertumbuhan koloni dan karakteristik mikroskopis dengan pewarnaan lactophenol cotton blue. Berdasarkan hasil penelitian sebanyak 3 sampel (13.6%) negatif dan 19 sampel (83.4%) positif terhadap pertumbuhan jamur. Beberapa jenis jamur yang telah ditemukan antara lain Aspergillus sp., Cunninghamella sp., Fusarium sp. dan Trichoderma sp.
The presence of pathogenic bacteria and fungi in food and the contamination of food with heavy metals and organic pollutants have become major global public health issues and economic concerns. Although eggs are often thought of as perfect, naturally packaged sources of nutrition, the eggs of chickens, other fowl, and sea turtles are in fact among the most commonly contaminated foods worldwide. The egg cuticle and eggshell are generally ineffective in preventing the entry of microbes and some chemicals. As a result of the overuse of antibiotics, pathogenic microorganisms that invade eggs are often found to be resistant to antimicrobial drugs. In addition, due to heavy usage in agriculture and various industries, synthetic organic chemicals and heavy metals enter the environment and can find their way into food chains and eventually contaminate eggs. In an effort to minimize these various types of contamination, regulations have been established to control the egg industry. However, in some regions of the world enforcement is lax and compliance is poor. The aim of this paper is to raise awareness of the need for rigorous enforcement of the rules, greater industry compliance with standards, increased monitoring, and further research on the public health issues.
Contamination of egg contents is not only a problem for human health, but can also be an indicator of environmental pollution. Contamination by bacteria (including multiply antibiotic resistant bacteria, or MARB), fungi, and heavy metals has been observed, and may occur either by direct transmission from the ovary and uterus (vertical infection), by horizontal infection from contaminated feces, or by transfer from the surroundings after the eggs have been laid.
The avian egg is porous with a thick, hard shell and soft outer coat. Its structure varies widely among species. The shell consists of protein matrix and 95-97% calcium carbonate crystals, and below it is the fibrous shell membrane surrounding the albumen. Turtle eggshell consists of three layers: outer calcareous, middle multistrata and inner membrane. The calcareous layer has loose nodular units varying in shape and size without interlocking attachments, resulting in numerous spaces and openings. Each nodular unit has spicules arranged in folded stacks. The eggshell membrane is the major supplier of calcium, as well as traces of other elements, during embryogenesis.
Penetration of bacteria into eggs is facilitated by the porous structure of the eggshell and egg membrane, and is primarily a function of time and the number of bacteria present. Microbial penetration of chicken and turtle eggshells takes place within a few minutes, depending on the type of bacteria. Pseudomonas aeruginosa was found to be the most concentrated in egg components followed by Salmonella typhimurium, Staphylococcus aureus and Escherichia coli, respectively. In addition, multiply antibiotic resistant bacteria (MARBs), containing R-plasmids with tetracycline efflux genes tet(A) and tet(B), have been isolated from commercial chickens and eggs.
On their migratory routes, sea turtles are exposed to various pollutants. Microorganisms from polluted feeding areas can enter the digestive tract and subsequently infect the ovary and uterus. Examination of turtle eggs and oviductal fluid reveals that MARBs also infect turtle eggs. Since antibiotics are highly diluted in the marine environment, MARBs have been used as bioindicators of contaminated effluents. Pseudomonas is the most frequent isolate, and studies on the bacteria in tertiary treated sewage effluent (TTSE) reveal that the majority are MARBs. When TTSE enters the sea, these MARBs may infect fish and turtles. Hence, consumption of contaminated fish and turtle eggs could lead to serious health problems.
Some fungi can grow on eggshells, infecting embryos and preventing gas exchange. Asperigillus flavus was found to produce aflatoxins which may interfere with embryonic development. In addition, bioaccumulation of heavy metals is common. Analysis of turtle eggs has revealed the presence of 12 heavy metals, of which Zn was the most concentrated.
The leatherback turtle is an endangered sea turtle whose numbers are in decline. There is a great effort world wide on the part of many conservationists to protect these turtles and their eggs. We previously demonstrated that blood from a leatherback hatchling was infected with a hemolytic acinetobacter bacterium, Acinetobacter sp. HM 746599, implying that the developing embryo may have been infected in the egg. Only about 50% of the eggs laid on a Costa Rican beach hatch due to predation, inundation and within nest factors. This study was conducted to determine whether high bacterial infection rate of eggs incubating in the dark, moist sands of the beach contributes to the low hatching rate. Samples were taken aseptically from adult cloacal fluids and failed and opened eggs in search of potentially lethal bacteria. We identified three bacterial species in selected cloned samples that exhibited hemolytic activity. These bacteria were species of the Bacillus, Pseudomonas and Aeromonas genera. Many of these bacterial species are known pathogens to humans and may account for developmental arrest of the turtle embryo. These bacterial species may also pose a danger to human workers who come in contact with them. Knowledge of the bacteria that can infect and possibly kill leatherback embryos may lead to treatment modalities of leatherback clutches with anti-microbial agents which would allow us to improve the hatching rates of these animals under controlled conditions.
Fossil fungi and arthropod body parts are present in one of 27 unhatched eggs in a turtle egg clutch from the Lower Cretaceous (Albian) Liangtoutang Formation, Zhejiang Province, China. The fossil fungal structures include branching septate hyphae, conidiophores supporting multiple phialides, and chains of up to five basipetal conidia (asexual spores). The morphology of the fossil fungus is similar to extant taxa within the genus Penicillium (order Eurotiales), making it the first reported intact Early Cretaceous asexual ascomycete and the earliest record of a presumed intact Penicillium. Biomineralization, a physiologic response to calcium-rich microenvironments, occurs in some extant fungi and may have facilitated detailed preservation of the fossil specimen. This rare evidence of fungal-animal association provides clues to clutch-related paleoecological interactions. The fungus-bearing egg occurs on the clutch periphery, whereas adjacent and more distant eggs show no evidence of fungal invasion. We suggest that the fungi were opportunistic contaminants invading after the egg was compromised, and the fungus failed to spread to adjacent eggs prior to burial and fossilization.
To date, there are limited studies on loggerhead turtle (Caretta caretta) eggshell ultrastructure and its elemental composition. Eggs were collected from turtle nests immediately after oviposition and post hatching. Three eggshell layers were recognized. The outer calcareous layer consists of loose nodular units of different shapes and sizes with loose attachment between the units, resulting in numerous spaces and openings. Each unit consists of CaCO3 crystals in aragonite (99%) and calcite (1%). The middle layer has several strata with numerous openings connecting the calcareous and the inner shell membrane. Crystallites of the middle layer are a mix of amorphous material with aragonite (62%) and calcite (38%). The inner shell membrane has numerous reticular fibers mixed predominantly with halite (NaCl) and small amounts of sylvite. Thermogravimetry analysis of the calcareous showed a low exothermic peak at 425°C, which corresponds to a transitional phase from aragonite to calcite. A high endothermic peak at 814°C corresponds to decomposition of calcite CaCO3 to CaO and CO2. Electron diffraction confirmed the presence of NaCl halite crystal. A significant difference was found in the percentage of elements and crystal configurations in the three layers. This study has value in assessing the emergence success in this endangered species.
Eggs of the loggerhead sea turtle, Caretta caretta, often fail to hatch. Infertility and embryonic mortality were investigated as sources of egg failure, showing that standard methods of estimating infertility of eggs produce overestimates. High species diversity of bacteria within eggs or the occurrence of the same bacteria in both females and their eggs was correlated with lower hatching success. Comparisons of hatching success were made among natural nests and two commonly used methods of egg relocation. Eggs relocated to polystyrene incubators had higher hatching success than did eggs reburied in other beach sites. Eggs in undisturbed natural nests had lower hatching success than relocated eggs. Thus, egg relocation is an effective conservation method, provided sites are chosen carefully.
Fungi are often found on the exterior of unhatched eggs in sea turtle nests in
eastern Australia. Artificial incubation of green
(Chelonia mydas) and loggerhead
(Caretta caretta) turtle eggs allowed the radiation of
fungi to be monitored. Fortuitous egg mortality provided a nutrient source for
common soil mycobiota (Fusarium solani and
Pseudallescheria boydii) and served as a focus for the
progressive spread of fungal hyphae to adjacent viable eggs. In extreme cases
the entire egg mass was enveloped and resulted in nil hatch success.
Hatching and emergence success were examined in 43 natural nests of the Mediterranean loggerhead turtle (Caretta caretta) in the Gosku delta, Turkey. Overall clutch size averaged 90.3 eggs (range 42-151). Of all eggs deposited, 58% hatched. In nine nests no hatching occurred, caused by repeated inundation in seven of these. In the successful nests, mean hatching success was 77%. Here egg failure was caused by microbial infection, infertility, embryonic mortality, and developmental abnormalities. Of all successfully hatched young, 18% failed to emerge from the nest. Straight carapace length of the hatchlings that failed to emerge was significantly lower than that of the successful ones. Emergence failure was highly correlated with a strongly compressed, solid beach sand type. [References: 14]
At Sandy Point National Wildlife Refuge, St Croix, US Virgin Islands, natural beach erosion results in the loss of 45–60% of the leatherback sea turtle Dermochelys coriacea eggs laid there per annum. In a 4-year study (1982–1985), 31·4–68·1% of the eggs laid annually (312 of 582 total clutches) were collected at oviposition and reburied in stable beach zones in an effort to mitigate losses to erosion. Reburial did not significantly increase the proportion of eggs per clutch that failed to develop, the proportion of eggs that contained pre-term dead embryos, the occurrence of embryonic deformity, or the risk of depredation for eggs or hatchlings. However, a consistently larger proportion of pipped, dead hatchlings in clutches that had been moved reduced overall hatch success in translocated as compared to in situ clutches (53·7% versus 64·1%, respectively). Collection and reburial of otherwise doomed eggs resulted in a net gain of c. 6650 hatchlings over 4 years.
Forty-eight samples of four popular commercial brands of black tea (Camellia sinensis L.) were purchased from the local markets in Muscat area, Sultanate of Oman. Tea leaves were surveyed for mycoflora. Five fungal species were isolated with A. niger as the most dominant in all the brands having percentage contamination ranging between 0.66% and 30.34%. Other fungi isolated were Aspergillusflavus, Penicillium spp. and Pacelomyces spp. but having average percentages of 0.6%, 0.84% and 0.21% respectively. Significant differences were found among the batches contaminated by A. niger. None of the 25 A. flavus strains screened for aflatoxins were found aflatoxigenic. The total ash, water-soluble ash, and mineral concentration of the samples were within the British standards and were not affected by fungal contamination. The results showed that black tea is contaminated by fungi that might constitute health hazards for humans. The post harvest contamination of tea could be eliminated or reduced if processing is conducted under more hygienic conditions.
Laparoscopies were performed on 225 hawksbill turtles (Eretmochelys imbricata) following nesting emergences on Milman Island, northern Great Barrier Reef, Australia during the 1992-1995 summer seasons. New recruits (first time breeders) made up between 9.8% and 14.3% of the nesting population across 4 summer seasons. Remigrants were not significantly larger or heavier than recruits, indicating that females nesting for the first time do not necessarily recruit to a nesting population at the smallest sizes. Further investigations are required to determine if the summer recruitment rate is reflective of the entire nesting population, which nests year round.
When a major wild bird food producer advised, in their catalogue for the year
2000, that they could not offer peanuts because of the high levels of aflatoxin, the phenomenon
of mycotoxins had really come into the public domain. In 2001 the same company was able to advise
that 'Although present in some peanut crops this season, aflatoxin is not currently
creating any major peanut supply problems'. Mycotoxins, and specifically peanuts and
the health of wild birds, were reviewed in earlier volumes of this journal
(Isaac 1994 a,
b) but the passage of time has not led to any reduction in the problems associated with the presence of mycotoxins in foods and animal feeds. Indeed, the improvement in analytical methods, and the implications of legislation in many countries have served to increase awareness of mycotoxins.
A total of 143 pistachio nut samples collected during harvest, storage and processing were examined for mould growth and aflatoxin production. The mould count was in the range of 103−104 cfu g−1 and 105−106 cfu g−1 for the harvest and storage samples, respectively. The growth of Aspergillus flavus was 38-5-39-5% on the surface of the shells and 6–16% on the kernels without aflatoxin production. The contamination level of A flavus varied among samples collected from different regions. Peeling off the soft shell of pistachio nuts by hand reduced the contamination risk of A flavus to kernels. The predominant flora on stored pistachio nuts were Aspergillus, Penicillium, Cladosporium, Rhizopus, while the genera of Ulocladium, Trichothecium, Aureobasidium and Eurotium were less frequent. Thirty-five percent of the A flavus isolates produced aflatoxins on synthetic media.
Effects of embryonic exposure to aflatoxin-B1 (AFB1) on the postnatal development of chicken mononuclear phagocytic system function was examined. Single exposure of 6-d chick embryos to 0.1, 0.5, and 1 micrograms AFB1 in 10 microL acetone was employed. Control embryos received 10 microliters solvent and sham-treated controls included embryos with a hole in the egg shell with no compound added. Aflatoxin B1 exposure caused a dose-related increase in embryonic mortality. After hatch, no differences were observed in body weight gain among treatment groups. The incidence of circulating thrombocytes was reduced in chicks exposed to the highest AFB1 dose with enhancement in monocyte and lymphocyte cell populations. Birds exposed to 1 microgram AFB1 recruited fewer macrophages in the peritoneal cavity after i.p. Sephadex elicitation along with reduced substrate adherence potential of peritoneal exudate cells. Similarly, macrophages from 0.5 and 1 micrograms AFB1-treated birds had depressed phagocytic potential. These results suggest that long-term immune depression of macrophage-mediated functions can occur following embryonic exposure to AFB1.
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Monosporium apiospermum Saccardo (Fungi, Deuteromycetes), asociado a los huevos de la tortuga marina Lepidochelys olivacea (Eschscholtz 1829) en Costa Rica
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