Otto Ortega Morales

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• Ph D. Environmental Microbiology.
• Senior professor at Autonomous University of Campeche

A previously reported bacterial bioemulsifier, here termed microbactan, was further analyzed to characterize its lipid component, molecular weight, ionic character and toxicity, along with its bioemulsifying potential for hydrophobic substrates at a range of temperatures, salinities and pH values. Analyses showed that microbactan is a high molecula...

Little is known about the dynamics of succession of fungi on limestone exposed in subtropical environments. In this study, the colonization of experimental blocks of compact and porous limestone by a fungal community derived from natural biofilms occurring on Structure X from the archaeological site of Becán (México), was studied using a cultivatio...

Microbial communities are ubiquitous in marine intertidal environments. These communities, which grow preferentially as biofilms on natural and artificial surfaces, carry out key processes contributing to the functioning of coastal environments and providing valuable services to human society, including carbon cycling, primary productivity, trophic...

Cultural heritage monuments may be discolored and degraded by growth and activity of living organisms. Microorganisms form biofilms on surfaces of stone, with resulting aesthetic and structural damage. The organisms involved are bacteria (including actinomycetes and cyanobacteria), fungi, archaea, algae, and lichens. Interactions between these orga...

It has previously been shown that epilithic bacterial biopolymers used as coatings influenced the physical properties (surface hardness and color change) at different levels and decreased the surface disaggregation of experimental limestone when evaluated at the laboratory level. A short-term study (30 days) was conducted to evaluate the performanc...

Concrete is the most utilized construction material worldwide. In the marine environment, it is subject to chemical degradation through reactions with chloride (the most important ion), and sulfate and magnesium ions in seawater, and to biodeterioration resulting from biological (initially microbiological) activities, principally acid production. T...

This article describes the consolidation effects of bacterial biopolymers synthesized by biofilm bacteria colonizing Mayan limestone buildings on the surface properties of limestone blocks, including disaggregation, hardness, and total color change at the laboratory level. The biopolymers evaluated, produced by bacterial isolates TM1B-488, TM1B-489...

The Earth’s oceans are the final resting place of anthropogenic wastes, mainly plastics, metals, rubber, and fabrics, in order of decreasing abundance. On reaching the sea and the benthos, most of these have assumed fragmented or particulate forms. They become colonized by marine microorganisms and later interact with macroorganisms, leading to pot...

The black soldier fly, Hermetia illucens (BSF, Diptera: Stratiomyidae) is an insect with high protein value and a potential feed agent for animals aimed for human consumption. The growth parameters of BSF larvae reared on four substrates—restaurant-waste, fruit-waste, fish-waste, and commercial tilapia food—for 41 days before processing for inclusi...

Cultural heritage buildings of stone construction require careful restorative actions to maintain them as close to the original condition as possible. This includes consolidation and cleaning of the structure. Traditional consolidants may have poor performance due to structural drawbacks such as low adhesion, poor penetration and flexibility. The r...

The influence of silver nanoparticles (AgNPs) on microbial biofilm colonization on natural calcareous rocks was studied in the Campeche marine intertidal environment in southeast Mexico. The biofilm formation was assessed by color spectrophotometer measurements represented in the CIELAB color space, digital image analysis, confocal laser scanning m...

The excessive use of fertilizers in agriculture is mainly due to the recognized plant requirements for soluble phosphorus. This problem has limited the implementation of sustainable agriculture. A viable alternative is to use phosphate solubilizing soil microorganisms. This work aimed to isolate inorganic phosphorus-solubilizing bacteria from the s...

Postharvest fungal decay causes economic loss and may cause human intoxication. Biological control of fungal decay of fruits using antagonistic native bacteria is a promising alternative. Leaf-associated (phyllosphere) bacteria are a promising yet underexploited source of antagonists for fungal control. A total of 108 bacterial isolates from mango...

Climatic factors, mainly rainfall, temperature and relative humidity, air pollution and biological activity influence the processes of stone degradation. This article analyses results of studies on microbial (mainly cyanobacterial) colonization of 32 cultural heritage stone monuments in Argentina, Belize, Brazil, Cambodia, Laos and Mexico, performe...

The inhibitory effect of Chrysomya rufifacies (Macquart) and Cochliomyia macellaria (Fabricius) larval excretions–secretions (ES) on Staphylococcus aureus was determined using a portable colorimetric method without the need for any dedicated spectral instrument. Polystyrene 96 well microplates were used and 100 μl of the bacterial inoculum (5 × 105...

Microbial growth may cause deterioration in buildings and objects of historical or cultural importance. Within the mechanisms of deterioration associated with the presence of microorganisms, biomineralization stands out, since it produces efflorescence, the formation of salt deposits on the surface of rocks, which causes changes in pigmentation, we...

Culex quinquefasciatus Say (Diptera: Culicidae), an arboviral and filarial vector, is one of the most widespread mosquitoes in the world. The indiscriminate use of synthetic chemical insecticides has led to the development of resistance in mosquito populations worldwide. The effect of continuous exposure to crude extracts of Argemone mexicana, the...

Abstract Nanoparticles (NPs) of metal oxides, sometimes referred to as engineered nanoparticles have been used to protect building surfaces against biofilm formation for many years, but their history in the Cultural Heritage world is rather short. Their first reported use was in 2010. Thereafter, a wealth of reports can be found in the literature,...

Chemical and biological weathering were studied on two historic churches in the city of Rio de Janeiro, Brazil. The churches exhibited contour scaling, granular disintegration and black crust development. High levels of SO4 were found in façade stones of one church, São José with significant levels of lead and copper. This suggests that vehicle emi...

Microbial biofilms frequently cause the esthetic and biological deterioration of stone monuments. Chichén Itzá, designated as a UNESCO World Heritage Site and as one of the seven new wonders of the world, is one Maya archeological site affected by biofilms. In the present study, we analyzed the biofilms at three different building complexes of Chic...

Halotolerant bioanodes are considered an attractive alternative in microbial electrochemical systems, as they can operate under higher conductive electrolytes, in comparison with traditional wastewater and freshwater bioanodes. The dependency between energetic performance and polarization potential has been addressed in several works; however the v...

Cadmium is a major heavy metal found in polluted aquatic environments, mainly derived from industrial production processes. We evaluated the biosorption of solubilized Cd2+using the extracellular polymeric substances (EPS) produced byBacillussp. MC3B-22 andMicrobacteriumsp. MC3B-10 (Microbactan); these bacteria were originally isolated from interti...

The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However, little is known about the role of fungal interactions in the colonization and establishment of fungal species. We analyzed the effects of intra- and interspecific interactions between...

Microsoft Excel database to determine the inhibition of the growth of each fungal species in the interactions in MEAC and CACO. (XLSX)

Types of interactions/responses between paired fungal species in MEAC (M) and CACO (C) media. Top row = response species; first column = challenge species. The corresponding categories are listed in Table 2. Clcl: C. cladosporioides, Cucl: C. clavata, Culu: C. lunata, Fuox: F. oxysporum, Fure: F. redolens, Hyph: Hyphomycete sp., Myro: M. roridum, P...

Hyphal growth (cm) of each fungus in isolation (control) and in interaction with fungal pairs. M = MEAC medium; C = CACO medium. Means (± SE, n = 5) followed by the same letter do not differ significantly between the two media according to Tukey’s post hoc test at P ≤ 0.05. Clcl: C. cladosporioides, Cucl: C. clavata, Culu: C. lunata, Fuox: F. oxysp...

Microsoft Excel database of responses in interactions to calculate the antagonism index. (XLSX)

Microsoft Excel database to calculate the percentage of inhibition and resistance of fungi in the interactions in culture medium. (XLSX)

Microsoft Excel database to calculate the percentage of surface colonization on the calcareous rock coupons. (XLSX)

Diffractograms of the XRD analysis after four months that the fungi interacted on the surface of limestone coupons. (ZIP)

We designed and synthesized five new 5-nitrothiazole-NSAID chimeras as analogues of nitazoxanide, using a DCC-activated amidation. Compounds 1-5 were tested in vitro against a panel of five protozoa: 2 amitochondriates (Giardia intestinalis, Trichomonas vaginalis) and 3 kinetoplastids (Leishmania mexicana, Leishmania amazonensis and Trypanosoma cru...

Background: We designed hybrid molecules between propamidine and benzimidazole in order to retain the antiprotozoal action, but decreasing the toxic effect of the molecule. Objective: Design and prepare 12 hybrids for testing their antiparasitic effect over three protozoa: Giardia intestinalis, Trichomonas vaginalis and Leishmania mexicana, as w...

Background and Aims: The colonization of lithic substrates by fungal communities is determined by the properties of the substrate (bioreceptivity) and climatic and microclimatic conditions. However, the effect of the exposure time of the limestone surface to the environment on fungal communities has not been extensively investigated. In this study,...

Coastal zones support fisheries that provide food for humans and feed for animals. The decline of fisheries worldwide has fostered the development of aquaculture. Recent research has shown that extracellular polymeric substances (EPS) synthesized by microorganisms contribute to sustainable aquaculture production, providing feed to the cultured spec...

This study involved the synthesis of several new derivatives of progesterone, 11a-hydroxyprogesterone, 11a-t-butyldimethylsilanyloxyprogesterone, and andrenosterone. The new derivatives were prepared by condensation of the 4-en-3-one moiety of the four steroids with 2-hydroxy-1-naphthaldehyde to afford a series of 4-(R)-hydroxy-(2-hydroxynaphtalen-...

Soil and rock surfaces support microbial communities involved in mineral weathering processes. Using selective isolation, fungi were obtained from limestone surfaces of Mayan monuments in the semi-arid climate at Yucatan, Mexico. A total of 101 isolates representing 53 different taxa were studied. Common fungi such as Fusarium, Pestalotiopsis, Tric...

Background: Several crysene derivatives have been prepared using different protocols; however some require special reagents and conditions. The aim of study involved the synthesis of two crysene derivative using androsterone and estrone as chemical tool. Methods: Crysene derivatives were prepared by a series of reactions that involve; 1) Synthesis...

Partiendo de 30 aislados bacterianos de diferentes tipos (fundamentalmente Bacillus), previamente aislados e identificados por métodos microbiológicos y moleculares, provenientes de biopelículas epilíticas traídas del Castillo de Chapultepec de la ciudad de México, DF. Se realizaron diferentes metodologías como comprobación y determinación de forma...

Introduction The Mayan archaeological sites belong to the World cultural heritage. The porous nature of limestone and stucco (calcareous coating) along with the high humidity and temperature typical of Southern Mexico and Central America, make these monuments prone to stone biodeterioration. The Mayan masks and stelae of the North Acropolis Complex...

The microbial composition of red and black patinas associated with representative buildings from the Mayan sites of Becan, Chicanna and Hormiguero (Campeche, Mexico) was studied. Algae and cyanobacteria were the prevalent microbial groups; the alga Trentepohlia and the coccoid cyanobacterium Gloeocapsa were dominant in terms of biomass. Orientation...

Background: Urban surface stones in Mexico City are exposed to a temperate climate and a range of atmospheric conditions ranging from mildly impacted to heavily polluted areas. In this study, we focused on the characterization of the cultivable fungal component of selected biological patinas in the surrounding area of Chapultepec castle, a historic...

Discoloring biofilms from Cambodian temples Angkor Wat, Preah Khan, and the Bayon and West Prasat in Angkor Thom contained a microbial community dominated by coccoid cyanobacteria. Molecular analysis identified Chroococcidiopsis as major colonizer, but low similarity values (<95%) suggested a similar genus or species not present in the databases. I...

An anaerobic down-flow fluidized bed reactor was inoculated with granular sludge and started-up with sulfate containing synthetic wastewater to promote the formation of a biofilm enriched in sulfate-reducing bacteria (SRB), to produce biogenic sulfide. The start-up was done in two stages operating the reactor in batch for 45days followed by 85days...

We aimed at determining the antagonistic behavior of bacteria derived from marine biofilms against terrestrial phytopathogenic fungi. Some bacteria closely related to Bacillus mojavensis (three isolates) and Bacillus firmus (one isolate) displayed antagonistic activity against Colletotrichum gloeosporioides ATCC 42374, selected as first screen orga...

Aqueous and organic extracts of twenty-seven species of marine algae (14 species of Rhodophyta, 5 species of Phaeophyta and 8 species of Chlorophyta) collected from the Gulf of Mexico and Caribbean coast of the Yucatan Peninsula (Mexico) were evaluated for their antileishmanial in vitro activity against Leishmania mexicana promastigote forms. The c...

Marine biofilms are a virtually untapped source of bioactive molecules that may find application as novel antifoulants in the marine paint industry. This study aimed at determining the potential of marine biofilm bacteria to produce novel biomolecules with potential application as natural antifoulants. Nine representative strains were isolated from...

Samples of peeling black crusts from modern and historic buildings in Campeche, Mexico, from a gravestone on the island of Dom Khon, Lao, and from the Anglican cathedral in Belize City were analyzed microbiologically, by scanning electron microscopy plus electron dispersive spectroscopy (EDS) and for pigment composition. In all cases, the surface w...

Aim: This study was performed to determine the potential of tropical intertidal biofilm bacteria as a source of novel exopolymers (EPS). Methods and Results: A screening procedure was implemented to detect EPS-producing biofilm bacteria. Isolates MC3B-10 and MC6B-22, identified respectively as a Microbacterium species and Bacillus species by 16S rD...

Biofilms were collected on discoloured limestone samples and on adhesive tape from historic buildings at the Mayan site of Edzna, in Campeche, Mexico. Grey, brown, and black areas were colonised predominantly by coccoid and colonial cyanobacteria, also detected as endoliths. The major biomass on the pink stone surface was Trentepohlia. At low power...

Cyanobacterial biofilms are complex communities of microorganisms that cause damaging activity on historic monuments. A combined molecular approach shows that cyanobacteria belonging to the order Pleurocapsales are the main colonizers at the Mayan site of Uxmal, Mexico, confirming previous microscopic and culture-based reports. An important, previo...

Viable bacterial counts, chemical markers, phospholipid fatty acid analysis (PLFA), and Fourier-transformed infrared spectroscopy (FTIR), together with electrochemical methods, were used to study biofilm dynamics and its impact on the corrosion resistance of UNS S31603 stainless steels exposed to the Gulf of Mexico seawater. Biofilms progressively...

Artificial substrata of different material composition were deployed at deep-sea hydrothermal areas on the Mid-Atlantic Ridge for exposure times ranging from 1 to 12 days. After 4 days of exposure, a very thick but loosely-bound biofilm formed on all surfaces. Two bacterial morphotypes dominated the attached microbial community: rod-shaped bacteria...

Biofilms on the salted ceiling of a limestone tunnel at the Mayan site of Edzna, Mexico, were characterised using SEM, EDS, chemical analysis, light microscopy, culture and pigment analysis. Major superficial biomass was pigmented, scytonemin-rich Subsection II cyanobacteria. Main endolithic phototrophs were Subsection I and II cyanobacteria and th...

A protocol is described for rapid DNA isolation from marine biofilm microorganisms embedded in large amounts of exopolysaccharides. The method is a modification of the hot phenol protocol used for plants tissues, where nonexpensive and easily available enzymes were used. The method is based on the incubation of biofilm biomass samples in an extract...

The epilithic biofilms colonizing the intertidal and splash zones of a rocky shore in the southern Gulf of Mexico were studied by phase contrast and scanning electron microscopy (SEM), along with phytopigment analyses. These biofilm communities comprised a mixed assemblage of phototrophs, dominated by cyanobacteria, with occasional diatoms and othe...

This chapter discusses the extracellular polymers of microbial communities colonizing ancient limestone monuments. Biofilms are layered microbial communities growing on inert and livingsurfaces in a variety of terrestrial and aquatic environments, including submerged artificial substrata, invertebrate teguments, sediments, soils, and rock surfaces....

10 20 30 40 50 60 70 80 90 100 H e x a n o O c t a n o H e x a d e c a n o B e n c e n o X il e n o P e t r ó le o A c e it e d e c a r r o A c e it e m in e r a l A c e i t e d e g ir a s o l A c e i t e d e m a í z A c e it e d e o li v a % de emulsificación Introducción. Las sustancias extracelulares poliméricas conocidas como EPS por sus siglas...

Buildings at the important archaeological sites of Uxmal and Kabah, Mexico, are being degraded by microbial biofilms. Phospholipid fatty acid (PLFA) and chlorophyll a analyses indicated that phototrophs were the major epilithic microorganisms and were more prevalent on interior walls than exterior walls. Culture and microscopical techniques showed...

The microbial epilithic communities associated with Uxmal Mayan stone monuments (Yucatan, Mexico) were preliminarily characterized by chemical and biochemical methods. The organic matter, organic carbon, and nitrogen content were within the respective ranges reported for other stone buildings, indicating that oligotrophic conditions prevailed at Ux...