Elaine Humphrey

A Description of occurrence and morphology of a new species of red-water forming Strombidium (Spirotrichea, Oligotrichia)

We describe a red‐water ciliate, Strombidium lingulum n. sp., collected from a marine fjord in British Columbia (BC), Canada. In August, 1995, red‐brown streaks were observed in the waters of Kyuquot Sound. BC. These streaks were composed of a ciliate population with an abundance in the surface of ˜ 1.5 × 103 cells ml‐1. Density was reduced to < 50 cells ml‐1 below the surface. The bloom persisted for only a few hours; cells were observed for 3‐4 days and were only occasionally observed in the weeks after the bloom. The red waters were speculated to be formed by a combination of downwelling events and an observed phototactic migration of the ciliate. As the ciliate was positively phototactic and pigmented, it may be mixotrophic; it was certainly heteroirophic, as it contained dinoflagellates and small ciliates in food vacuoles. Ciliates were preserved in Lugols iodine and then both protargol stained and prepared for scanning electron microscopy.

Brief communication: state of preservation of tissues from ancient human remains found in a glacier in Canada.

Ancient remains preserved in glaciers present a unique opportunity for us to advance our knowledge of human origins, diversity, and health, a central focus of anthropological studies. Cellular components of hard and soft tissue from frozen human remains dated between 1670 to 1850 cal AD recovered from a glacier in Canada were studied. Despite the expected ice crystal damage in some samples, regions of recognizable structure and ultrastructure were observed. We found that the state of preservation was tissue specific and that in some tissues the organelles were better preserved than in others. Skeletal, connective, nervous, and epithelial tissues were recognizable in some of the samples. DNA had been previously extracted from these remains and this study illustrates that the ability to successfully extract DNA may correlate with good preservation of histology.

Porphyrobacter meromictius sp. nov., an appendaged bacterium, that produces Bacteriochlorophyll a.

Four Gram-negative strains (ML4T, ML19, ML31, ML32) of nonmotile, appendaged, budding bacteria were isolated from the meromictic Mahoney Lake in British Columbia, Canada. The strains were red to brown-red in color and produced bacteriochlorophyll a incorporated into photosynthetic pigment-protein complexes. Phylogenetic analysis has placed these strains within the class Alphaproteobacteria, with the closest relatives being members of the genera Erythrobacter, Porphyrobacter, and Erythromicrobium. Morphological features warrant their inclusion within the genus Porphyrobacter and these strains can be readily distinguished from other species of this genus on the basis of a mesophilic temperature range, a broad pH range, and tolerance to extremely high NaCl and Na2SO4 concentrations, in keeping with the environment from which they were isolated, a Na2SO4-dominated meromictic lake. These isolates utilize a variety of organic substrates for aerobic chemoheterotrophic growth and do not grow under anaerobic conditions, in either the presence or the absence of light. All strains require vitamin B12, and strains ML4T and ML19 require biotin. The DNA G + C contents ranged from 62.2 to 64.9 mol%. Phenotypic and phyletic data support the classification of strains ML4T, ML19, ML31, and ML32 as a novel Porphyrobacter species for which the name Porphyrobacter meromictius sp. nov. is proposed.

Metalloid reducing bacteria isolated from deep ocean hydrothermal vents of the Juan de Fuca Ridge, Pseudoalteromonas telluritireducens sp. nov. and Pseudoalteromonas spiralis sp. nov.

Five strains of Gram-negative, rod, curved rod and spiral-shaped bacteria were isolated from the vicinity of deep ocean hydrothermal vents along the Main Endeavour Segment of the Juan de Fuca Ridge in the Pacific Ocean. All strains showed remarkable resistance to high levels of toxic metalloid oxyanions, and were capable of reducing the oxyanions tellurite and selenite to their less toxic elemental forms. Phylogenetic analysis of four strains identified these isolates as close relatives of the genus Pseudoalteromonas within the class Gammaproteobacteria. Pseudoalteromonas agarivorans was the closest relative of strains Te-1-1 and Se-1-2-redT, with, respectively, 99.5 and 99.8% 16S rDNA sequence similarity. Strain Te-2-2T was most closely related to Pseudoalteromonas paragorgicola, with 99.8% 16S rDNA sequence similarity. The DNA G+C base composition was 39.6 to 41.8 mol%, in agreement with other members of the genus Pseudoalteromonas. However, the isolates showed important morphological and physiological differences from previously described species of this genus, with one group forming rod-shaped bacteria typical of Pseudoalteromonas and the other forming vibrioid- to spiral-shaped cells. Based on these differences, and on phylogenetic data, we propose the creation of the new species Pseudoalteromonas telluritireducens sp. nov., with strain Se-1-2-redT (DSMZ=16098T=VKM B-2382T) as the type strain, and Pseudoalteromonas spiralis sp. nov., with strain Te-2-2T (DSMZ=16099T=VKM B-2383T) as the type strain.

High‐pressure freezing of spermiogenic nuclei supports a dynamic chromatin model for the histone‐to‐protamine transition

In this study, we present for the first time a description of the dynamic chromatin changes that occur during spermiogenesis in the internally fertilizing caenogastropod mollusc Nucella lamellosa. Chromatin condensation in developing sperm cells in some animals, such as the model biological system used here, involves the histone‐to‐protamine transition and proceeds through a patterning stage from granules to fibers to lamellae. This may be due to the physicochemical phenomenon of phase separation by spinodal decomposition, a dynamic mechanism known to generate pattern. This hypothesis is based entirely on published transmission electron microscopy photomicrographs using conventional fixation technology. We now report that spermatid nuclear patterning and subsequent condensation in testis of Nucella lamellosa fixed by high‐pressure freezing and freeze substitution (HPF/FS) is similar to that in glutaraldehyde‐fixed testis, and can be related to the processing of sperm nuclear basic proteins (SNBPs). J. Cell. Biochem. 108: 1399–1409, 2009.

Imaging and diffraction of protein crystallization using TEM.

Structural biology relies on good-quality protein crystals in order for structure determination. Many factors affect the growth process of a protein crystal including the way it nucleates and the types of damage and contamination during its growth. Although the nucleation process and quality of a crystal is vital to structure determination, they are both under-studied areas of research. Our research begins to explore ways of measuring the quality of protein crystals, using TEM, thus overcoming the problems associated with viewing wet specimens in a vacuum. Our current understanding of nucleation is that it is a two-step mechanism involving the formation of nuclei from dense liquid clusters; however; it is still unclear whether nuclei first start as amorphous aggregates or as crystalline lattices. Potentially, electron diffraction may be capable of uncovering this process. Using TEM imaging and diffraction of lysozyme as a model protein crystal, we report the internal two-dimensional strain and the density of crystallites in a protein crystal, at a resolution never seen before. The TEM diffraction shows unique features of crystal mosaicity that can be directly correlated to TEM images.

Examining Protein Crystallization Using Scanning Electron Microscopy

Elucidation of protein structure using X-ray crystallography relies on the quality of the crystal. Crystals suffer from many different types of disorder, some of which occur during crystal nucleation and early crystal growth. To date, there are few studies surrounding the quality and nucleation of protein crystals partly due to difficulties surrounding viewing biological samples at high resolution. Recent research has led our current understanding of nucleation to be a two-step mechanism involving the formation of nuclei from dense liquid clusters; it is still unclear whether nuclei first start as amorphous aggregate or as crystalline lattices. Our research examines this mechanism through the use of electron microscopy. Using scanning electron microscopy imaging of the protein crystal growth process, a stacking, spiraling manner of growth is observed. The tops of the pyramid-like tetragonal protein crystal structures measure ~0.2 μm across and contain ~125,000 lysozyme units. This noncrystalline area experiences strain due to growth of the protein crystal. Our work shows that it is possible to view detailed early stage protein crystal growth using a wet scanning electron microscopy technique, thereby overcoming the problem of viewing liquids in a vacuum.

Structural Analysis Of Hair Samples For Identification Of Ancient Textiles

Fig.1 Former Chief Lenard George of the Burrard Band Coast Salish wearing the subject wooldog blanket The Coast Salish people from the Northwest Coast of British Columbia, Washington State and Northern Oregon are known for their expertise in weaving blankets from a mixture of mountain goat hair, plant fibres, and the hair of a now extinct dog called a wooldog. In the subject blanket, the mountain goat hair was easily identifiable and the other hair from the wooldog did not match up to anything in our extensive databank of hair pictures. The nearest we could find was Samoyed dog. What we needed was a sample of authenticated wooldog

Virtual Electron Microscopy for Undergraduate/Graduate Classes

University of British Columbia, Canada ech@interchange.ubc.ca How do you give 1150 undergraduates in an introductory cell biology course (Biology 200) access to electron microscopes? Students often ask if they can see the electron microscopes. They often ask if they will have an opportunity to learn EM. As part of the course material, students are expected to recognize the images produced by different EM techniques, know the advantages and disadvantages of these techniques and interpret 2-dimensional micrographs in 3 dimensions. This is akin to teaching the theory of baking bread without ever smelling it in the oven. A pilot project was designed to address getting round the impossibility of bringing 1150+ students into the BioImaging Facility. This initiative gave selected undergraduates a hands-on experience of SEM in the BioImaging Facility and allowed the rest of their classmates to share that experience. The students were invited to hand in proposals for SEM projects at the beginning of term. The winning proposals are available on the course website. One student from each of the 5 lecture sections was to be selected

Multi-modal Microscopy of Almost Nothing - Aerogels

Aerogels, consisting mostly of air caught in a matrix of low-density strands of Silicon Dioxide, were first made by supercritical drying of gels in the 1930s. When viewed on a white background they almost disappear, and on a black background they appear blue due to Rayleigh scattering. There is essentially no boundary scattering of light off the solid surface. While excellent thermal insulators, they have a multitude of other uses. For purposes outlined below, we required macro, micro, and nano 2D and 3D images of aerogel sheets of densities >27 mg/cc (20X air at STP) with modified surfaces.