A novel set of structures within the elasmobranch,ovarian follicle

Elasmobranch fishes produce some of the largest oocytes known, exceeding 10 cm in diameter. Using various microscopy techniques we investigated the structural adaptations which facilitate the production of these large egg cells in three species of shark: the Atlantic sharpnose shark, Rhizoprionodon terraenovae, dusky smoothound, Mustelus canis and the little gulper shark, Centrophorus uyato. The ovarian follicle of elasmobranchs follows the typical vertebrate pattern, with one notable exception; the zona pellucida reaches extreme widths, over 70 μm, during early oogenesis. Contact between the follicle cells and the oocyte across the zona pellucida is necessary for oogenesis. We describe here a novel set of large, tube‐like structures, which we named follicle cell processes that bridge this gap. The follicle cell processes are more robust than the microvilli associated with the follicle cells and the oocyte plasma membrane and much longer. During early oogenesis the follicle increases in size relatively quickly resulting in a wide zona pellucida. At this stage the follicle cell processes appear taut, uniform and radially oriented. As oogenesis continues the zona pellucida narrows and the follicle cell processes change their orientation, appearing to wrap around the oocyte. The presence of the contractile protein actin within the follicle cell processes and their change in orientation may well be an adaptation for maintaining the integrity of these large oocytes. The follicle cell processes also contain electron dense material, identical to material found within the follicle cells, suggesting a role in the transport of metabolites to the developing oocyte. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Drinking and water expulsion in the diamondback turtle Malaclemys terrapin

Postural and kinematic characteristics of the drinking behaviour in the diamondback turtle, Malaclemys terrapin (Latreille) were investigated by video and high-speed filming experiments. Head, jaw and throat movements in drinking cycles are described. Postures of neck and head were compared for three water depths (2, 10 and 30 mm). Water expulsion, occurring after the turtle was disturbed, is also kinematically described. Finally, a drinking mechanism in the turtle is proposed.     

Stimulation of human B cells specific for Candida albicans for monoclonal antibody production

Abstract The stimulation and immortalisation of human peripheral blood B lymphocytes specific for Candida albicans antigen were investigated. An in vitro immunisation system was employed which involved pretreatment of mononuclear cells with l -leucyl l -leucine methyl ester which removes the suppressive effects of CD8 + T cells, NK cells and monocytes. The remaining cells, CD4 + T cells, B cells and dendritic cells, were cultured with antigen and a mixture of cytokines. A mixture of IL-2, −4 and −6 was found to be optimal for antibody production as determined by an Elispot assay. Transformation of the activated B cells by Epstein Barr virus was found to be optimal after 2 days and lines secreting anti- Candida antibodies were established. These lines could form the basis for specific monoclonal antibody production by generating hybridomas, or by a newly described technique whereby cDNA encoding antibody Fab regions is transferred into phage display libraries. The overall strategy might be generally applicable for the generation of human monoclonal antibodies to infectious agents.     

Staining Flagellate Protozoa by Various Silver-Protein Compounds

Seven samples of silver protein (Protargol type) were tested on flagellate protozoa from the alimentary tract of frogs, golden hamsters, and termites. The samples consisted of one of Protargol (Winthrop's prewar German), one of Protargol S (Winthrop-Stearns, Inc., present manufacture, Commission Certified), and five of the experimental batches (4Z, 20, 20B, 22, and 36) by H. A. Davenport and collaborators (1952). The pre-war Protargol is rated best and batch 22 second best for staining of all flagellates. Protargol S gave uniform, but only fair results, with all organisms, while batch 20B, better than Protargol S in several instances, was poorer in a few. Thus Protargol S and batch 20B are rated third, as about equal. Batch 4Z is rated fourth; and batch 20, which stained some species, fifth. Batch 36 stained no protozoa. The tests show that while the present Protargol S is usable for protozoa, it is still inferior to the old German variety. Since some of the experimental batches, none of which was made by exactly the same process, gave promising results, further study of the relation between manufacturing process and subsequent staining reaction should be fruitful.