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A review of Techniques used in the preparation, curation and conservation of Microsciope slides at the Natural History Museum, London.
... New (1974) also suggested that Chlorazol Black E was suitable only for polyvinyl alcohol-lactophenol or methyl cellulose/carbowax mounting media. This contention was challenged by Brown (1997), who noted that the Natural History Museum in london had used Chlorazol Black E with Euparal with no issues, and that polyvinyl alcohol-lactophenol was an unsuitable entomological mounting medium due to continued shrinkage after the mount had set. Robinson (1976) also mounted in Euparal. ...
... Acid Fuchsin has been called an unreliable stain for chitin (Nagy, 1978). There can be issues with fading of Acid Fuchsin in mounts made with Canada balsam, due to residues of clove oil in the mount (Brown, 1997). other clearing oils have similar effects of fading Acid Fuchsin (Fig. 8) with eucalyptus oil breaking down the stain within minutes (Chick, 2011). ...
... Aniline dyes are particularly prone to fading in Canada Balsam (Southgate, 1927). Brown (1997) suggested that Euparal preserves Aniline Blues colouration. Solutions of Aniline Blue have a short shelf life, developing mould and losing staining properties, but shelf life can be improved by making the following solutions: Aniline Blue (water soluble) 1% in 50% glycerol and 1% phenol or Aniline Blue (water soluble) in 95% alcohol (Richardson, 2014). ...
Slide mounted entomological specimens often require the aid of contrast techniques to improve the clarity of morphological characteristics. Methods can involve the use of techniques such as Phase contrast, Dark field or differential interference contrast microscopy (DIC), however where an entomologist may only have access to simple brightfield microscopy chemical staining of the specimen may be used to improve contrast. For whole mounts of entomological specimens, a single stain, occasionally two, are often used, in comparison to histological sections that often employ multiple stains in complex protocols. A number of authors have proposed different stains and staining methods for a number of insect groups with few considering the long term qualities of the stain, it has previously been shown that aniline dyes are prone to fading in Canada Balsam mounts, and that some stains fade even when protected from sunlight. This paper aims to summarise the knowledge of stains used for entomological specimens and provide details on the archival qualities.
... need for toxic solvents, incompatibility with remnants of water, gradual yellowing and high price. These drawbacks were mostly overcome by the invention of its analogue Euparal (Brown, 1997;Ravikumar et al., 2014;Neuhaus et al., 2017). Another long-used embedding medium for solid samples is celloidin (Plowman, 1904), but it is hardly suitable for bones (Arnold, 1951;Woodruff & Norris, 1955;Callis, 2002). ...
... No medium is completely satisfactory (Mollenhauer, 1993;Ellis, 2003b;Ravikumar et al., 2014). Wrong choice of the medium caused loss of many scientifically important samples (Brown, 1997;Neuhaus et al., 2017). So, comparative tests of various embedding media, especially widely accessible ones and especially in respect of longevity, retain importance (Neuhaus et al., 2017;Heck et al., 2020). ...
Study of ground sections is the most used and, in some respects, still irreplaceable method for examination the microstructure of paleontological and many other hard and friable objects. At the same time, paleontological samples are relatively difficult for preparations of high-quality thin sections. Many techniques and means, particularly embedding media, have been proposed, but they are often hardly accessible, imperfect or insufficiently studied. A promising and easily accessible non-specialized medium, UV-curable acrylic adhesive (glue for glass) was tested for embedding and mounting of objects with diverse mechanical and optical properties. It shows notably good results, in particular durability, reliable adhesion, ease of use and lack of significant birefringence, which makes it especially valuable for polarized light microscopy. Properties of such adhesives are reviewed and compared with properties of epoxy resins and a number of other media. Disadvantages of the adhesives and ways to deal with them are also elucidated. In addition, broadly accessible tools and methods of sawing, embedding, grinding, mounting and other stages of the work are discussed. Efficiency of a number of grinding agents is measured. On the basis of all these results, a technique of making ground sections using easily accessible means was developed and described step by step. The technique was designed for fossil bones, but is applicable to diverse dry samples, including paleontological, neontological and geological ones.
... This would render it transparent, making only the stained tissue elements visible (1,3). mounting medium with an RI too far either side of 1.53 will lead to poor clarity and contrast (1,4). ...
... When drying, it shrinks significantly and should be applied liberally to the slide. They set fast and frequently withdraw from the coverslip's edge (4). Prolonged exposure to D.P.X. ...
Introduction: Mounting is the final stage in histologically preparing a slide and creates a permanent the bond between the coverslip and the slide, preventing breakage, air drying artefacts, and stain fading. Materials & methods: In this study, fifty slides were prepared, twenty-five of which were mounted using DPX and twenty five using cyanoacrylate adhesive. The slides were assessed for clarity of nuclear and cytoplasmic details, adhesion between coverslip and slide, and the presence of air bubbles by two blinded observers. Results: The results showed that adhesion between coverslip and slide was better when mounted with cyanoacrylate adhesive, but better clarity of nuclear and cytoplasmic details and minimal air bubble entrapment was seen when tissue sections were mounted using DPX. Conclusion: Therefore, the use of cyanoacrylate adhesive cannot be an alternative to DPX for mounting soft tissue sections.
... Pre-1900 slides have a higher percentage of unstained or very lightly stained tissue. While the exact mounting medium is unknown for most of the slides, it is assumed based on the number of slides that have yellowed with age that Canada balsam was the most frequently used mounting medium (Brown, 1997). The slides mounted with balsam have aged relatively well. ...
... For the slides mounted between approximately 1968 and 1972, the same is not true. During this time, the mounting medium changed to a solution, probably a gum chloral medium (Brown, 1997), that has since crystalized grossly, impeding one's ability to observe anatomical characteristics. Luckily, the bulk of the collection is made up of slides that were prepared using Canada balsam. ...
As herbaria move to digitize their collections, the question remains of how to efficiently digitize collections other than standard herbarium sheets, such as wood slide collections. Beginning in September 2018, the Harvard University Herbaria began a project to image and digitize the wood slides contained in the Bailey-Wetmore Wood Collection. The primary goal of this project was to produce images of the wood tissue that could be used for specimen-level research and to make them available on the internet for remote scholarship. A secondary goal was to establish best practices for digitizing and imaging a microscope slide collection of tissue sections. Due to the size of the wood slide collection (approximately 30,000 slides), a medical histology scanner and virtual microscopy software were used to image these slides. This article outlines the workflow used to create these images and compares the results with digital resources currently available for wood anatomy research. Prior to this project, the very little of the Bailey-Wetmore Wood Collection was cataloged digitally and none of it was imaged, which made access to this unique collection difficult. By imaging and digitizing 6605 slides in the collection, this project has demonstrated how other institutions can make similar slide collections available to the broader scientific community.
... For genitalia preparation, the abdomen was detached from the insect body and macerated in KOH 10% solution for 24 h. Genitalia was then extracted and cleaned in distilled water, then soaked into 70% ethanol and eventually fixed in 96% ethanol before mounting on a slide with Euparal (Brown, 1997). ...
The Asian walnut moth, Garella musculana (Erschov, 1874) (Lepidoptera: Nolidae), is a major pest of walnut. Native to Central Asia, it was found to be invasive in 2008 in Sevastopol (Crimea) and nowadays widespread in Turkey, Bulgaria, Romania and Russia. Here, we account for the finding of G. musculana in NE Italy (Veneto region) in 2021, where adults were found in a light lamp, representing the first record of the Asian walnut moth for this country and Western Europe. Adult specimens were identified morphologically on both external characters and genitalia features. G. musculana larvae and damage were also observed on a plantation of Juglans regia L. (Fagales: Juglandaceae) located in Veneto in October 2021. A COI‐barcoding analysis was performed to attain a molecular characterization of our specimens and probate our morphological identification. However, because no sequence of G. musculana was present in major gene databases and the similarity of our sequences with those attributed to Garella ruficirra (Hampson, 1905) (Lepidoptera: Nolidae) made clear that these taxa deserved further scrutiny regarding their specific distinction. Some subtle differences in the male terminalia could be found between them and their vast geographic distributions, but the strong similarity in most features calls for further morphological and genetical insights on a broad set of samples to assess whether they represent two closely related, substantially parapatric species, or a unique, geographically varying entity. Solving this issue may turn out crucial in the identification and proper management of walnut moths of the genus Garella.
... The physical features of the microscope slides influence the resulting images, and these include the type of specimens being preserved, the mounting techniques and curation processes used, and the slides themselves [2]. In this study we consider slides having a standard size of 25 mm × 75 mm (approximately 3 × 1 ) [4]. The resolution of the specimen images used can vary from 900 pixels per inch (ppi) 1 to 28,500 ppi. 2 ...
Semantic segmentation has been proposed as a tool to accelerate the processing of natural history collection images. However, developing a flexible and resilient segmentation network requires an approach for adaptation which allows processing different datasets with minimal training and validation. This paper presents a cross-validation approach designed to determine whether a semantic segmentation network possesses the flexibility required for application across different collections and institutions. Consequently, the specific objectives of cross-validating the semantic segmentation network are to (a) evaluate the effectiveness of the network for segmenting image sets derived from collections different from the one in which the network was initially trained on; and (b) test the adaptability of the segmentation network for use in other types of collections. The resilience to data variations from different institutions and the portability of the network across different types of collections are required to confirm its general applicability. The proposed validation method is tested on the Natural History Museum semantic segmentation network, designed to process entomological microscope slides. The proposed semantic segmentation network is evaluated through a series of cross-validation experiments designed to test using data from two types of collections: microscope slides (from three institutions) and herbarium sheets (from seven institutions). The main contribution of this work is the method, software and ground truth sets created for this cross-validation as they can be reused in testing similar segmentation proposals in the context of digitization of natural history collections. The cross-validation of segmentation methods should be a required step in the integration of such methods into image processing workflows for natural history collections.
... The adult samples of B. tabci were slide mounted with Canada balsam following the previous method [19]. The taxonomic features employed for the morphological identification were the compound eyes, forewings, mesothoracic legs, antennae, the external genital organs and abdomen [20]. ...
Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the major pests of many crops worldwide. It is a cryptic species complex composed of at least 39 different indistinguishable species. However, the common species of this insect in Iraq including Karbala Province is not fully recognized. Thus, the main aim of this research was to explore the genetic characteristics of this species in Karbala province, Iraq based on the mitochondrial DNA CO1sequencing analysis as well as control it using some chemical pesticides and nanoparticles. The mtCO1 results suggest B. tabaci species complex have a high level of genetic polymorphic, and three members of B. tabaci (B, B2, and MEAM2) were identified in (Nursery threshold Husseiniya, Al-Husayniyah, and Karbala desert), respectively. The most common type was B, which is Middle East-Asia Minor1 (MEAM1) according to the global dataset of this species complex. Furthermore, the influence of the ZnO and MgO nanoparticles evaluated were similar to the pesticides examined. Thus, they are a potential alternative method can be harnessed to control the whitefly.
Haematoxylin is the most common routinely used dye in histopathology. It stains the nuclei, and in combination with the cytoplasmic stain eosin, it provides good contrast. Haematoxylin also stains collagenous material, minerals, and myelin fibres. Hematoxylin is oxidised to haematin which is a weak anionic dye. When a metallic salt (mordant) is combined with haematin, then a cationic dye-metal complex is formed that behaves as a strong basic dye and combines with the nucleic acid. This chapter discusses the different types of hematoxylin solutions, their uses, and the staining procedure.
Location and specimen deposition of Kinorhyncha were analysed for the time period 1863–2020 based on data generated from the World Register of Marine Species (WoRMS). From at least 11,760 specimens collected during this time period according to the scientific literature from all fields of research, 41% were deposited in a reference collection, 21% in a personal collection, and for 38% it is unknown whether or not they were deposited at all. Whereas no type material was mentioned in publications to have been deposited in a reference collection before 1938, the situation improved in the 1960s–1980s with most specimens deposited. The most recent time period 2011–2020 suffered again from a low deposition rate of 55% for the material of new species as types plus 15% as non-types and an overall deposition rate of 42% for types plus non-types of new and known species. This is the first time that the deposition behaviour is documented for an entire animal group for all fields of research over a time period of 158 years. The implications for kinorhynch research and for zoological science at large are discussed. The results presented are regarded as a wake-up call for scientists to consider their current deposition behaviour, to the International Commission on Zoological Nomenclature, funding and permitting bodies, as well as journal editors to tighten their deposition requirements, and to the funding bodies to provide funding for the deposition of specimens as soon as ever possible in order to keep the loss of the cultural heritage in natural history to a minimum.
Microscope slide collections represent extremely valuable depositories of research material in a natural history, forensic, veterinary, and medical context. Unfortunately, most mounting media of these slides deteriorate over time, with the reason for this not yet understood at all. In this study, Raman spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, and different types of light microscopy were used to investigate the ageing behaviour of naturally aged slides from museum collections and the experimentally aged media of Canada balsam and PermountTM, representing a natural and a synthetic resin, respectively, with both being based on mixtures of various terpenes. Whereas Canada balsam clearly revealed chemical ageing processes, visible as increasing colouration, PermountTM showed physical deterioration recognisable by the increasing number of cracks, which even often impacted a mounted specimen. Noticeable changes to the chemical and physical properties of these mounting media take decades in the case of Canada balsam but just a few years in the case of PermountTM. Our results question whether or not Canada balsam should really be regarded as a mounting medium that lasts for centuries, if its increasing degree of polymerisation can lead to a mount which is no longer restorable.
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