Microscopic Mounts Research Articles

Three-Dimensional Printed Abdominal Imaging Windows for In Vivo Imaging of Deep-Lying Tissues

The ability to microscopically image diseased or damaged tissue throughout a longitudinal study in living mice would provide more insight into disease progression than having just a couple of time points to study. In vivo disease development and monitoring provides more insight than in vitro studies as well. In this study, we developed permanent 3D-printed, surgically implantable abdominal imaging windows (AIWs) to allow for longitudinal imaging of deep-lying tissues or organs in the abdominal cavity of living mice. They are designed to prevent organ movement while allowing the animal to behave normally throughout longitudinal studies. The AIW also acts as its own mounting bracket for attaching them to a custom 3D printed microscope mount that attaches to the stage of a microscope and houses the animal inside. During the imaging of the living animal, cellular and macroscopic changes over time in one location can be observed because markers can be used to find the same spot in each imaging session. We were able to deliver cancer cells to the pancreas and use the AIW to image the disease progression. The design of the AIWs can be expanded to include secondary features, such as delivery and manipulation ports and guides, and to make windows for imaging the brain, subcutaneous implants, and mammary tissue. In all, these 3D-printed AIWs and their microscope mount provide a system for enhancing the ability to image and study cellular and disease progression of deep-lying abdominal tissues of living animals during longitudinal studies.

First report of Dematophora bunodes causing root rot of taro (Colocasia esculenta ) and leatherleaf fern (Rumohra adiantiformis) in Brazil.

Colocasia esculenta, taro (T), is a major staple food crop in the tropics, including Brazil. Rumohra adiantiformis, leatherhead fern (LF), is broadly cultivated for its ornamental fronds that are used as a component of flower arrangements. Soft root rot of T and LF, and accompanying rapid plant wilt and death, was observed in plantations in Espírito Santo (Brazil), at Venda Nova do Imigrante, in April 2014 (LF) and July 2015 (T). Great losses were observed. Firstly, a few individual scattered plants showed symptoms of disease in the plantations, then aggregates of plants and, after a few seasons, the majority of the plants in the field died before harvest, leading to the abandonment of the activity by farmers. A white mycelial matt was observed on the crown and roots ofying T and LF plants. Infected corms become necrotic and dark brown mycelial strands were observed internally in tissues. Diseased organs were carefully washed and surface sterilized in 10% sodium hypochlorite. Samples of tissue were removed from the boundary of necrotic tissues and placed on potato dextrose-agar (PDA) plates and incubated at 23±2 C in the dark. Homogeneous mycelial colonies were isolated from both T and LF and, upon observation of microscope mounts under an Olympus BX 53 light microscope, pear-shaped hyphal swellings at the septae (Castro et al. 2013) were observed. . A representative isolate from each host was deposited in the local culture collection as COAD 2911 (LF isolate) and COAD 2912 (T isolate). Additionally, DNA was extracted from each culture using the Wizard Genomic DNA Purification Kit (Promega) and the internal transcriptional spacer region was PCR amplified using the primers ITS5 and ITS1 (White et al. 1990). The amplicons were sequenced by MACROGEN (http://www.macrogen.com). Consensus sequences were deposited in GenBank: MW561595 (LF), MW561596 (T). Consensus regions were compared against other sequences available in Genbank. A BLASTn analysis resulted in LF and T sequences respectively 99% (526/531bp) and 98% (412/420 bp) identity with that of Dematophora bunodes (MN984619). Additionally, a phylogenetic analysis of a selected sequence alignment was performed on the CIPRES webportal (Miller et al., 2010) using MrBayes v.3.1.1 (Ronquist & Huelsenbeck, 2003). A phylogenetic tree was generated showing that the placement of LF and T isolates is in D. bunodes (Wittstein et al. 2020). Pathogenicity tests were performed for LF and T isolates against their original hosts. For inoculum, bags of twice-autoclaved parboiled rice were seeded separately with each isolate, which were allowed to colonize the rice for two weeks. Four healthy young LF and T plants were utilized. Two extra healthy plants grown in the same conditions, but not inoculated, served as controls. Thirty g of Dematophora-colonized rice was placed in direct contact with stems or roots of each LF or T plant. Plants were maintained in a dew chamber for 48 h after inoculation and then transferred to a greenhouse bench. All inoculated plants developed wilt and root rot and died after 15-20 days. Controls remained healthy. White mycelial colonies were formed over tissues of diseased LF and T and upon observation under the microscope, typical pear-shaped swellings were observed in slides prepared from newly obtained pure cultures from LF and T. Dematophora bunodes (formerly Rosellinia bunnodes) has a worldwide distribution and is well known as a polyphagous plant pathogen (Farr and Rossman, 2020) but has never been reported as a pathogen either of LF or T before in Brazil and worldwide. Its report on LF and T further expands an already large host-range and resolves the etiology of the disease on LF and T.

Swim bladder mycosis in farmed rainbow trout Oncorhynchus mykiss caused by Phoma herbarum and experimental verification of pathogenicity.

In this study, spontaneous swim bladder mycosis was documented in a farmed fingerling rainbow trout from a raceway culture system. At necropsy, the gross lesions included a thickened swim bladder wall, and the posterior portion of the swim bladder was enlarged due to massive hyperplasia of muscle. A microscopic wet mount examination of the swim bladder contents revealed abundant septate hyphae, and histopathological examination showed periodic acid-Schiff-positive mycelia in the lumen and wall of the swim bladder. Histopathological examination of the thickened posterior swim bladder revealed muscle hyperplasia with expansion by inflammatory cells. The causative agent was identified as Phoma herbarum through morphological analysis and DNA sequencing. The disease was reproduced in rainbow trout fingerlings using intraperitoneal injection of a spore suspension. Necropsy in dead and moribund fish revealed extensive congestion and haemorrhages in the serosa of visceral organs and in liver and abdominal serosanguinous fluid. Histopathological examination showed severe hepatic congestion, sinusoidal dilatation, Kupffer cell reactivity, leukostasis and degenerative changes. Fungi were disseminated to the liver, pyloric caeca, kidney, spleen and heart. Although infections caused by Phoma spp. have been repeatedly reported in fish, species identification has been hampered by extensive taxonomic changes. The results of this study confirmed the pathogenicity of P. herbarum in salmonids by using a reliably identified strain during experimental fish infection and provides new knowledge regarding the course of infection.

Workshop: Care & Conservation of Zoological Collections

Zoological collections house a huge range of biological diversity preserved in a wide variety of ways ranging from microscope mounts to whole animals preserved in fluids. The result is that these collections consist of a wide range of differing materials which can make the long term care and conservation of such collections a considerable challenge. This workshop is designed for museum professionals with the aim of giving an introductory overview on museum conservation approaches towards the care of zoological collections. This will be achieved through identifying the key risks and looking at the application of both remedial and preventative conservation methodologies to their care. The format of the workshop will be lectures on specific topics with group discussions, along with (where feasible) activities in small groups and practical examinations of specimens. Topics covered will include: Introduction to the concepts of ‘museum conservation’ and its application within the Natural Sciences. The types of material found in zoological collections – an overview of the core collection types, the chemistry of preservation and the potential long term challenges these present. An overview of the key agents of deterioration. Environmental effects and how to recognise them. Awareness of hazardous materials and core H&S issues encountered with the care and handling of zoological collections. Assessing collections and deciding conservation priorities. Fur, feathers and bones - practical conservation approaches to cleaning, consolidation and repair. Fluid collections - practical conservation approaches to handling, identifying fluids and carrying out remedial activities. Other key collection areas – e.g. conservation of entomology and other dried invertebrate collections; microscope slide collections. Consideration of the care and conservation of specialist collections e.g. historic models such as Blaschka glass models. Discussion and feedback from attendees will be a core part of the day.

English

Amylase enzymes are industrially important enzymes used in food, sugar, textile, pharmaceutical, paper and detergent industries. The main objective of this study was to isolate, produce and optimize α-amylase enzyme using a fungal strain isolated from fruit peel soil wastes. Media optimization was done by one-factor at a time method. Average values of duplicate experiments were taken. Microsoft office Excel worksheet 2010 was used for data analysis. Soil samples were collected from three places and a total of 89 fungal isolates were isolated. All isolates were screened for their potential to produce amylase based on the clear zone formation on starch agar media, of which isolate FAB-211 showed the maximum potential to produce amylase and considered for further study. The isolate was further characterized based on colony morphology and microscopic mount and the isolate FAB-211 was Aspergillus niger. Important process parameters affecting amylase activity with the fungal isolate were optimized. The maximum activity (0.483 U/ml) was observed at pH of 6.0 and temperature at 45°C was found to be the best for amylase activity (1.241 U/ml). The highest and least alpha-amylase production was found when 6 and 2 discs spore of A. niger FAB-211 were used, respectively. Maximum yield of alpha amylase (0.281 U/ml) was observed on the 3rd day of incubation period followed by 4, 6 and 5th days. Maltose and yeast extract were found to be the best carbon and nitrogen sources, respectively. Therefore, further optimization of parameters and characterization of A. niger FAB-211 amylase is important for their application in industries. Key words: Fungi, amylase enzyme, Aspergillus niger, FAB-211.

Abstract A22: A window into 3D culture: A multi-modal imaging compatible bioreactor for developing tumor growth models

Abstract Introduction: We aim to use clinical imaging data to initialize and constrain tumor-specific biophysical models of in situ cell proliferation, motility, and therapy response. Towards this goal, we have developed a 3D in vitro cell culture system that can be non-invasively interrogated by both microscopy and magnetic resonance imaging (MRI). The system supports long-term cell growth and allows for control over microenvironmental factors such as drug delivery and extracellular matrix. Cellular and subcellular level data obtained from confocal microscopy define the cell state and local environment and improve interpretation of the lower resolution, clinically relevant information provided by MRI. Here, we report system design and initial data collection. Apparatus Design: The system consists of the bioreactor body, a reservoir with a filter enabling CO2 equilibration in the incubator, and a peristaltic pump to drive media flow throughout the tubing and bioreactor. The bioreactor body has a cavity for cells embedded in extracellular matrix, a hollow-fiber for delivery of nutrients (FiberCell Systems, Frederick, MD), and is sealed using a gasket and lid with a confocal microscopy window. The removable lid makes the bioreactor reusable after sterilization. Data Collection: As a simplified model of 3D tumor growth, we selected the triple negative breast cancer cell line MDA-MB-231 embedded in 0.4% agarose. MDA-MB-231 cells were labeled with H2B-RFP and FUCCI-GFP to image cell nuclei and entry into the cell cycle, respectively, enabling measurements of cell number and cell division. Fluorescence microscopy images were collected on a Zeiss spinning disk confocal microscope using a 20x objective. Sixty 200 μm z -stacks using the green and red channels can be collected in approximately 90 minutes. The bioreactor is secured into a custom microscope mount using screws, ensuring it is placed in the same location every time. A reference point is marked on the first imaging day, to enable longitudinal alignment at subsequent imaging sessions. The bioreactor was also designed for use on a 9.4 T Agilent Technologies (Palo Alto, CA) MRI scanner equipped with a 38-mm quadrature RF coil, which is conventionally used for small animal studies. Diffusion-weighted (DW) images have been acquired using a standard pulsed gradient spin echo sequence with four b values (67, 200, 400, and 800 s/mm2) and gradients applied simultaneously along three orthogonal directions (x , y , and z ). The apparent diffusion coefficient obtained from the DW-MRI data provides an indirect measure of cell number. Images were acquired at a resolution of 100x100x1000 μm3. Conclusion: Overall, we have designed and fabricated a multi-modal imaging compatible bioreactor that supports long-term 3D cell growth under controlled conditions. We have successfully collected both MRI and confocal microscopy data on the bioreactor system at multiple time points. Currently, we are working towards co-registering these two imaging data types and extending the life of the bioreactor. Our novel multi-modal imaging compatible bioreactor is ideal for iterative biophysical tumor model refinement, providing a bridge to predictive models exclusively populated with non-invasive clinical imaging data. Citation Format: Abigail M. Searfoss, Matthew T. McKenna, Vito Quaranta, Thomas E. Yankeelov, Erin C. Rericha. A window into 3D culture: A multi-modal imaging compatible bioreactor for developing tumor growth models. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A22.

Study on Hair Morphology to Distinguish the Dominant Races in Malaysia for Forensic Investigation

Hair evidence is one of the most common types of evidence encountered in criminal investigations. The present preliminary study is aimed to investigate the racial discrimination through hair morphology viz. inner cuticle margin, cuticle thickness and medulla pattern among Malay, Chinese and Indian in Malaysia. Following standard procedure, a total of 180 volunteers’ head hair samples, each 60 (30 males, 30 females) from consented Malay, Chinese and Indian, have been collected for analysis. Approximately 1 cm length of each hair was cut and suitably mounted using clean microscope slide, cover slide and mounting medium for analysis. The prepared hair slides were subjected to microscopic examination under different magnifications viz. 40X, 100X and 400X. The result of the hair investigation showed marked differences in hair morphology among the three races. The frequency and percentage of distribution of different hair morphology were tabulated and also presented in the form of bar graphs. This pilot study, the first of its kind in Malaysia provided a promising result in hair investigation showing racial discrimination among dominant races in Malaysia and the result of the investigation can be very well used in crime investigation.

Inhibited experimental mouse corneal neovascularization by CCR3 antagonist

To explore the effect of CCR3 antagonist on the development of experimental corneal neovascularization. Mouse corneas were burned by NaOH to induce corneal neovascularization.Fifty four clean male BABL/c mice aged 7-8 weeks were divided into control group, CCR3 antagonist group and VEGF antibody positive group according to randomized number table. The gene expression of CCR3 and its ligand eotaxin in burned corneas was examined by Real-time PCR. CCR3 antagonist was locally administrated after alkali injury and the formation of corneal neovascular 2 weeks after injury was examined using a digital camera linked to a slit lamp microscope and corneal whole mount staining with CD31. The mRNA and protein expression of chemokines in burned corneas was detected by Real-time PCR and western blot. Compared to control group, CCR3 antagonist treated mice resulted in significantly decreased corneal neovascularization. The related CNV area was 0.51 ± 0.03 in the CCR3 antagonist group, and that in the control group was 0.77 ± 0.15, with significant difference between them (t = 12.91, P = 0.00).Western blot detection did not show significant difference of VEGF protein expression between two groups.Expression level of VEGF in the CCR3 antagonist group was 0.91 ± 0.24, and that in the control group was 1.15 ± 0.30, showing no significant difference (t = 1.08, P = 0.34). Alkali-induced corneal neovascularization was inhibited by CCR3 antagonist. The mechanism that CCR3 pathway plays an important role in corneal neovascularization needs further exploration.

A Survey of Bacterial and Fungal Oppurtunistic Infections among HIV Clients in Kano Metropolis

Ethical clearances from Aminu Kano Teaching Hospital Kano (AKTH) and Hospitals Management Board, Kano State were obtained and 600 patients were randomly selected, their informed consents obtained and tested for HIV by rapid tests using serial algorithm as recommended by World Health Organization and adopted by the Federal Ministry of Health. The biodata of the patients were collected confidentially and anonymously. All those confirmed to be HIV positive were further tested for CD4 cell count by flowcytometry technique (Pertec®) and were selected and screened for opportunistic bacterial and fungal pathogens using sputum samples. The bacterial pathogens were isolated using Blood and Chocolate agar plates and identified biochemically except the Acid Fast Bacilli (AFB) which was tested in all the HIV positive samples by Ziehl Neelson staining technique. The fungal pathogens were isolated using Sabouraud Dextrose Agar (SDA) with antibiotics and Brain Heart Infusion ( BHI ) Blood agar also with antibiotics and identified morphologically by wet microscopic mount. Results of this study showed that out of the 600 blood samples tested, 72 ( 12 % ) were HIV positive, 46 (7.7%) were male while 26 (4.3%) were female. On the basis of age groups, 30 – 40 years were found to have the highest number of HIV positive (40%, n = 72), then followed by 15-20 years ( 40%, n = 72 ), while the lowest number was recorded among 5 – 14 years. CD4 cells count categorization by WHO showed highest number of HIV positive among those with CD4 cells of ≥ 500 cells/ml with 37 cases (51% n = 72), then followed by those in the third category with CD4 count of ≤ 200 cell/ml (28%, n = 72) while in the category of 200 – 499 cell/ml, 15 cases (21% n= 72) were recorded. The overall organisms isolated among the 72 HIV positive patients were 139 as follows: Streptococcus pneumoniae (4%), Klebsiella pneumoniae (11%), Pseudomonas aerugenosa (19%), Haemophilus influenzae (4% ), Acid Fast Bacilli (23%), Candida albicans (26%), Aspergillus species (11%), Cryptococcus neoformans (1.4%), and Histoplasma capsulatum (0.6%). Highest number of the opportunistic pathogens was recorded in the ≤200 cell/ml CD4 category with 61 organisms while the other two categories both recorded 39 organisms each. In this study therefore, the number of the opportunistic pathogens isolated among HIV positives indicates significant co-existence of polymicrobial infection due to immune suppression (p < 0.05). Also significant association was found between low CD4 cells count of ≤200 cells/ml and the occurrence of major opportunistic bacterial and fungal pathogens such as Mycobacterium tuberculosis and Candida albicans ( p < 0.05) respectively. Key words: HIV, AIDS, Bacteria, Fungi, Opportunistic pathogens, CD4 cells.

INFLUENCE OF USING A POLLEN REPLACER ON THE BEE FAMILY DEVELOPMENT

SUMMARY The pollen replacers used as supplementary source o f dietary protein for the bees during wintering and their effect on the maintenance and d evelopment of the bee families is a common objective of the beekeepers (M alaiu A., 2005). We tested a pollen replacer made of soybean meal, dry brewer yeasts, skimmed powder milk, in a watery environment with extraction ratio 4/1. After 24 h, the supernatant w as lyophilised and a fine yellowish power with a specific smell was obtained. The biological material was represented by bee families of Carpatina Foti breed, the field variety. The control group consis ted of 4 bee families of similar breed and variety, with the same population al area spread over 7 frame intervals, weighing in average 1.85 kg, with similar reserves of 1.85 kg honey and 2 kg of pollen and virgin wax, but without supplementary feed. In the experimental group, the pollen replacer was given as cakes during winter (October 25 through February 1). The effects of this pollen replacer on the speed of growth of the young bees a nd on the development of the hypopharyngeal glands that produce the royal jelly in the worker bees, were monitored. It was observed that the supplementary feeding with pollen replacer did not influence significantly the size of the population when the w inter was over, an average physiological decrease of 27% being observed in both groups (M arghita � , L.A., 2002). In the experimental group, the consumption of 65% of the pollen replace r cakes resulted in an intense growth of the young bees (the area occupied by the young bees was 30 dm 2 , compared to 12 dm≤ in the control group) and a uniform arrangement in the hon eycomb, as concentric rings of freshly laid eggs, of young larvae and enclosed young bees. The hypopharyngeal glands were investigated by optical microscope, 10 samples from each nucleus, after fresh preparations were placed between the microscope mount and slide. It was observed that the hypopharyngeal glands harvested on Fabruary 1 st from the worker bees of the experimental group had progressed through all four stages, their acini being fully developed and the cisterne having a mat consistency. The hypopharyngeal glands of the worker bees from the control group had the characteristics of the stage 3 of development, with the acini nuclei located in the centre of the cells, which shows tha t their activity started later than in the experimental group.

On Mounting Delicate Bryophytes in Glycerol

Glycerine jelly is an effective substitute microscopic mounting medium for now difficult-to-obtain gum chloral preparations. It does not collapse most thin bryophyte tissues, preserves color responses of cell walls to potassium hydroxide solution, and is made from easily obtained, non-poisonous ingredients. Like other glycerol-based mountants, it evaporates only very slowly and, with luting, is essentially permanent. The study slide is a valuable adjutant to research in bryology. A well labeled permanent or semi-permanent preparation allows repeated examination of morphological traits that allows serial comparisons during revisionary work and serves to reinforce poorly remembered distinctions or illuminate vaguely worded keys during routine identification. For critical species, I find two slides, each with two coverslip-protected mounts, provide space for mounting moss capsules, perichaetia, perigonia, habit (of smaller species), and sections of stem and leaves in a manner that allows subsequent illustration if needed. As anyone who has worked with microscopic mounts knows, taking the time to prepare a slide well saves much time and frustration in the long run. To this end, I have pursued (Zander 1982, 1983, 1993) a better slide medium than gum chloral preparations such as Hoyer's Solution (Anderson 1954), which have severe osmotic effects in many bryophyte species. In addition, chloral hydrate is presently governed under controlled-substance laws in the U.S.A. and good-quality powdered gum arabic is now difficult to obtain. Glycerine jelly has been used for many years as a bryological microslide mountant (Gatenby & Beams 1950; Gray 1954; Murray 1926) but has been superseded in bryological work to a great extent by Hoyer's Solution (Anderson 1954), which is more convenient to work with since it does not need to be heated. Hoyer's Solution and its variants are likewise made with glycerol, and thus last for many years since glycerol has a very low vapor pressure (boiling point 2900C). The high index of refraction of glycerol (much higher than that of cellulose), makes mounted tissue easy to observe un-

A case of the shakes: Resonance in a microscope mounting system

That electron microscopes, especially modern, high performance ones, are susceptible to environmental interference, is well known. The author, aware of this susceptibility, has nevertheless experienced what were, to him, initially surprising difficulties in commissioning a new instrument. He offers this paper in the hope that it may help others avoid the pitfalls which so easily engulfed him.The microscopy area at MIT was constructed fourteen years ago after two different manufacturers' installation engineers surveyed the space and declared it satisfactory. The microscopes installed at that time performed well and met their specifications with no difficulty - in the case of those that are still on-site, they continue to do so to this day.Five years ago an ultra-high resolution TEM was installed. It was mounted on a series of synthetic rubber vibration absorbing pads. It proved difficult to meet the performance specifications on this instrument, despite the company service engineers checking the site and passing it as satisfactory. The specification was 0.18nm point-topoint, while the achievable resolution was 0.25nm.

Rapid microscopical diagnosis of deep-seated mycoses following maceration of fresh specimens and staining with optical brighteners.

A fluorescent staining procedure, which used to be recommended for the detection of fungi in skin and nail scrapings, can be adapted for the rapid detection of fungal elements in non-sectioned biopsies or respiratory secretions. The specimens are directly stained with an optical brightener (Blankophor P flüssig, Cellufluor, Uvitex 2B) preferentially after exposure to 20% aqueous potassium hydroxide solution. The procedure can also be applied to Gram-stained microscopic mounts. The high intensity of the fluorescence elicited allows rapid microscopic screening at low magnifications.

Sclerites, Spicules and Systematics: The Researches of Marthe Deflandre-Rigaud (1902-1987)

The history of discovery of the major groups of microfossils falls into four principal phases. The earliest observations were made during the late 18th and first half of the 19th century, an era when microscopes were, for the first time, becoming readily available and gentlemen of leisure were finding them an intriguing alternative to their traditional recreations. Microorganisms were admired for their beauty quite as much as for the information they gave about the nature of the infusoria in the lakes and oceans of present and past. With enormous patience, these men manipulated diatoms, silicoflagellates and radiolarians into elaborate geometric patterns, producing microscopic mounts that were veritable works of art. Publications on the infusoria were sometimes expensive and elaborate, with handsome hand-colored plates. Much more frequently, however, they were meagerly illustrated, with over-brief systematic descriptions or none at all; indeed, the microfossils sometimes served merely as an inadequate underpinning to a ponderous philosophical discursus. Very often, after a single publication had been produced, its writer's interest passed to other topics and there was no follow-up.

An improved dimpling technique for the preparation of TEM specimens

Traditional techniques for the preparation of TEM specimens have been electrolytic thinning or a combination of mechanical prethinning (dimpling) and ion-beam milling. The focus of discussion for this paper is an advanced technique for the mechanical dimpling procedure.A new device has been designed so that TEM specimens are consistently produced, thus minimizing the need for intensive operator intervention, trial and error methods, and ion-milling time. This instrument incorporates many of the features utilized in standard dimpling techniques. In addition, it provides the ability to simultaneously rotate and oscillate the specimen, resulting in an increased electron beam transparent area. Actual grinding rates are programmed with a resolution of 0.1 μ.m/min, thus eliminating the reliance on adjustable counterweight systems to control the grinding rate/force. A 40X microscope and movable magnetic specimen mount permit precise positioning that enables the dimple to be located at any point on the specimen. This is illustrated in Fig. 3, where the dimple is positioned on the interface of interest. An integral lamp back lights the specimen so that transparency can be detected without removing the specimen from the instrument. During the preparation process, the actual specimen thickness is continuously indicated on an alphanumeric display.

An Autochthonous Phaeohyphomycotic Nail Infection in Canada Caused by Hendersonula toruloidea

A case of an autochthonous toenail infection caused by Hendersonula toruloidea is presented. H. toruloidea was characterized by thick, branching septate brown-walled hyphae of a non-dermatophyte in microscopic tissue mounts in 25% Na0H with 5% glycerol. Cultures grew out on Littman's agar and Sabouraud peptone glucose agar plus chloramphenicol, but only if cycloheximide was not present. In vitro, the H. toruloidea isolate was characterized by copious 1-to 2-celled hyaline to dark-brown arthroconidia deriving from the fragmentation of aerial hyphae. It is likely that more infections due to H. toruloidea will be diagnosed if cycloheximide-free media are routinely used in the isolation of organisms from suspected dermatophyte infections.

The effect of vibration on vision during microsurgery.

This study was initiated to assess the effects of vibrating optics on a microsurgeon's ability to visualize. The results have led to criteria of image displacement versus frequency which could be applied to the design of a surgical-microscope mounting system. To provide minimum added strain to the microsurgeon, the ideal microscope mounting system should not transmit vibration from the hospital environment to the microscope optics at a level that is detectable by the visual system of the surgeon. This can be avoided by isolating the microscope mounting system from the vibratory environment of the hospital and by designing the microscope support system to minimize vibrations at frequencies that are most readily detectable by the human visual system.

Studies in the Genus Scytinostromella

The genus Scytinostromella was proposed by Parmasto (1968) to accommodate dimitic species of resupinate Corticiaceae, with nondextrinoid skeletal hyphae and amyloid spores, and with or without cystidia and/or gloeocystidia. The species he placed in the genus were transferred from Gloeocystidiellum, leaving it more homogeneous. Microscopic mounts were stained with 2% phloxine added to a drop of KOH and viewed under both bright field and phase contrast. Spores were studied and measured in Melzer's reagent (Singer, 1962), and gloeocystidia in sulfuric benzaldehyde (Boidin, 1951). Abbreviations of herbaria were taken from Holmgren and Keuken (1974). The following account summarizes the taxa of the genus.

Staining preparations for phytoplankton and periphyton

Phytoplankton and periphyton can be prepared for study by staining preserved samples with acid fuchsin, dehydrating them and then preparing membrane-filter (phytoplankton) or slurry (periphyton) microscope mounts. The procedures outlined provide a single preparation for periphyton or phytoplankton samples and also permit the investigator to distinguish diatoms alive at the time of collection from those already dead, based on visible cell contents. Comparisons of losses of algae and ratios of living to dead diatoms in fresh and prepared periphyton samples indicated little error due to preparation. Percentages of dead diatoms observed in stained samples from diverse habitats are presented.

Effect of Chilling Temperatures on the Protoplasmic Streaming of Plants from Different Climates

A microscope mount was designed so that specimen temperatures could be monitored and controlled without impairing phase contrast optics and used to measure rates of protoplasmic streaming between 0 and 25 °C in trichome cells of Lycopersicon esculentum, Lycopersicon hirsutum, Citrullus vulgaris, Tradescantia albiflora, Digitalis purpurea, and Veronica persica. Between 10 and 20 °C the rates of streaming varied from 2–6 μm s−1 depending on the temperature, and differences between the species were small. The temperature coefficient of streaming rates was found to increase as the temperature was lowered so that the plot of log rate against temperature had a steeper slope at the lower temperatures. The largest temperature cofficients were for the warmth-requiring L. esculentum (tomato) and C. vulgaris (water melon), and the smallest for the temperate-zone plants V. persica (speedwell) and D. purpurea (foxglove). The changes in rate always occurred over a range of temperature; no ‘critical temperature’was observed below which streaming abruptly stopped and above which it was active, although the amount of streaming as well as the rate decreased as the lowest temperatures were approached. The temperatures experienced by the specimens during the experiment did not affect the recovery of normal streaming rates between about 10 and 20 °C. In a population of a wild tomato, Lycopersicon hirsutum Humb. and Bonpl., collected from different altitudes in Peru and Ecuador, i.e. from locations of different environmental temperature, the rate of protoplasmic streaming at 5 °C was greatest in the varieties collected from the highest altitudes. The results suggest that streaming rates correlate with genetic adaptation to low temperature in the species examined.