ArticlePDF Available

A review of Techniques used in the preparation, curation and conservation of Microsciope slides at the Natural History Museum, London.

Authors:
... 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). ...
Article
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.
... 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. ...
Article
Full-text available
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.
... 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 ...
Article
Full-text available
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]. ...
Article
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.
... Genitalia were dissected following the methodology presented by Brown (1997) and Robinson (1976). The wings and the male genitalia were stained with phenosafranin. ...
Article
Full-text available
Alloclita canariensis Koster & Junnilainen sp. nov. is described from the Canary Islands Fuerteventura, Gran Canaria, Lanzarote and Tenerife. Two specimens from Gran Canaria were previously misidentified as A. francoeuriae Walsingham, 1905, a North African species. We record A. francoeuriae also as new for the Canary Islands, from Fuerteventura. The potential hostplants of A. canariensis are Asteriscus species (Asteraceae). DNA barcodes of both species are provided and compared with five other Alloclita species. The related Alloclita subitariella (Riedl, 1993), only known from the holotype from Saudi Arabia, is redescribed. These three species are placed in the new Alloclita francoeuriae group.
... may take 5-15 min to image, small vibrations lead to distortions (Wesseln, 2015;Sivaguru et al., 2018). Common solid mounting media, such as Canada balsam and glycerine gelatin, take longer to dry and can absorb organic compounds within the samples, resulting in background fluorescence (Brown, 1997;Ravikumar et al., 2014;Neuhaus et al., 2017). This increases background noise and reduces the signal of the imaged specimen. ...
Article
Airyscan confocal superresolution microscopy is a new optical technique that can detect morphological features smaller than the diffraction limit of light. It captures both the external and internal ornamentation of modern and fossil pollen. Airyscan combines the ease of use of optical microscopy methods, such as confocal and brightfield microscopy (BM), with the high-resolution imaging of electron microscopy (EM). Modern and fossil pollen grains were imaged using Airyscan, BM, and EM to assess the viability of Airyscan as an alternative for EM. Our results demonstrate that: (1) Airyscan can capture diagnostic features of extant and fossil pollen similar to EM; (2) one-to-one comparisons of Airyscan images with other optical methods are possible (e.g., BM and conventional confocal); (3) Airyscan captures three-dimensional data, allowing reconstruction of pollen grains in different views; and (4) the time and effort required for Airyscan imaging is significantly less than that for EM. This paper demonstrates that Airyscan superresolution microscopy is a high-throughput alternative for morphological analyses of pollen specimens.
... The morphology of the intact cysticerci and rostellar hooks of the metacestodes and adult tapeworms was examined. The hooks crowns were localized and identified by mounting the cysticerci with introverted scolices in Faure's fluid (Brown, 1997), without staining. To analyses the rostellar hooks in the all tapeworms, the crowns were mechanically cut from the scolices, and then was temporarily mounted in Faure's fluid, for photography and study. ...
Article
Full-text available
The tapeworm Taenia lynciscapreoli is a new species of the genus Taenia described in 2016, and which remains poorly understood. The aim of the present study is to extend current knowledge regarding its, morphology and genome. Biological material was analysed from three species of wild animals: Eurasian lynx (Lynx lynx), roe deer (Capreolus capreolus) and moose (Alces alces). Twenty-four adult tapeworms and four larvae were obtained from Eurasian lynx and roe deer respectively; none were detected in the studied moose. On the basis of morphometric (hooks measurements) and molecular analysis (partial 780 bp cox 1 gene sequences), the analysed tapeworm was identified as Taenia lynciscapreoli species. The phylogenetic analysis of the obtained sequences identified two haplotypes. The obtained findings can be used to supplement the species description. To our knowledge this is the first morphological and molecular identification of T. lynciscapreoli in roe deer, intermediate host, in Poland.
... Several specimens were used from each population to confirm the species. They were slide-mounted with Canada balsam using the procedure described by Brown (1997). The taxonomic characteristics used for identification were based on Hill (1969) and were related to the compound eyes, forewings, mesothoracic legs, antennae, the external genital organs and abdomen. ...
Article
Whiteflies (Hemiptera: Aleyrodidae) are major pests of many crops worldwide. Bemisia tabaci is a cryptic species complex composed of more than 39 putative species. Understanding which putative species of B. tabaci are predominant in an area is vital for effective pest management since they may vary considerably with respect to insecticide resistance, host plant range and virus transmission. Here, for the first time, the genetic diversity, the symbiont diversity and population structure of B. tabaci in Iraq were studied. Fourteen populations were analysed using mitochondrial cytochrome C oxidase subunit 1 (mtCO1) sequencing and microsatellite genotyping. Symbiotic bacteria were identified using 16S rRNA and 23S rRNA sequencing. MtCO1 sequencing detected two putative species of B. tabaci. The predominant putative species in Iraq was Middle East‐Asia Minor (MEAM) 1 subcladeB2. In addition, one individual was MEAM1‐subcladeB. The second putative species was a single individual of MEAM2. The microsatellite data indicated low genetic diversity, with no biologically informative clustering. All MEAM1 individuals harboured one primary symbiont, Portiera aleyrodidarum, and most (96%) have two secondary symbionts: Hamiltonella sp. and Rickettsia sp. This study has identified the genetic diversity and population structure of B. tabaci in Iraq. Further investigation is needed to update the pest status of B. tabaci in this region. The current data, combined with investigations into the capacity of the various putative species to transmit plant viruses, especially tomato yellow leaf curl virus, will aid pest management and horticultural production.
... In total, 16 adult insects collected in Cariblanco and Vereh were used for the description of the species. To determine the morphology of the species, genitalia were dissected following previously published methodology (Robinson 1976, Brown 1997. For the slides of the male genitalia, phenosafranin was used for staining. ...
Article
Full-text available
Fruits of Miconia calvescens DC. (Melastomataceae) were dissected to study insect frugivory in this plant in its native habitat in Costa Rica. Larvae of an unknown Mompha species (Lepidoptera: Momphidae), Anthonomus monostigma Champion (Coleoptera: Curculionidae), and unidentified Diptera and Hymenoptera were found in M. calvescens fruits. The Mompha species, described here as new as Mompha luteofascia Koster & Badenes-Pérez, was the most abundant insect frugivore in M. calvescens, infesting up to 38.1% of the fruits sampled. Feeding damage by M. luteofascia was positively correlated with fruit maturity, and resulted in significantly reduced numbers of seeds and rates of seed germination. Miconia calvescens fruits with medium damage (50–75% of the pulp missing) and high damage (75–100% of the pulp missing) had an average of 96 and 99 seeds, respectively, whereas undamaged fruits contained an average of 127 seeds per fruit. In fruits with medium and high fruit damage, only 1.9 and 0.1% of the seeds germinated, respectively, whereas 34.8% of the seeds germinated in undamaged fruits. Mompha luteofascia developed through three instars, as determined from measurement of head capsules. Larvae usually fed as one individual per each fruit attacked, exiting fruit to pupate in foliage or litter. Parasitism of M. luteofascia larvae was substantial, averaging 64 and 38% at the two study sites. Although host specificity of M. luteofascia has not been evaluated, the significant reductions in seed numbers and seed germination caused by its larvae indicate that this species deserves further assessment as a potential biological control agent of M. calvescens.
Article
Full-text available
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.
ResearchGate has not been able to resolve any references for this publication.