In Vivo and In Vitro Sperm Interaction with Oviductal Epithelial Cells of Llama

Sperm reservoirs in South American Camelids would be crucial for successful fertilization. Since ovulation occurs approximately 36 h after mating, the maintenance of the sperm viability in the oviduct waiting for the ovum is a critical reproductive event. Our study aimed at determining whether the isthmus or the utero tubal junction (UTJ) could function as a sperm reservoir in llama by means of in vivo and in vitro experiments. For the in vivo experiments, the oviducts of adult females with a dominant follicle bigger than 7 mm were examined for the presence of sperm at 6, 18, 24, 28 and 35 h after mating. The results using scanning and transmission electron microscopy showed ultrastructural differences between isthmus and UTJ with respect to (1) predominance of secretory cells in the UTJ and ciliated cells in the isthmus epithelium and (2) cytoplasmic bulbous projection of the secretory cells in the UTJ. Sperm adhered by a mucus‐like substance were seen only in the UTJ at 6, 18, 24 and 28 h post‐mating. Lack of sperm adhered to oviductal mucosa was observed around ovulation (35 h). In vitro experiments demonstrated higher ability of UTJ epithelial cell explants with respect to isthmus explants to bind sperm in a co‐cultured system. The anatomical features and the presence of a sperm bonding agent in the UTJ together with the in vitro differential binding of sperm to UTJ explants strongly suggest that both may be feasible mechanisms that facilitate sperm storage in this oviductal region in llama.     

Environmental influences on histological changes in the reproductive cycle of four New South Wales sea urchins

The suitability of a sea urchin population for commercial harvesting and culturing depends on the timing and duration of the spawning season. Pilot studies have shown that the New South Wales echinoids produce mature gonads for several months.Investigations were made into the influence of those exogenous factors which could be modified under aquacultural conditions.Temperature and food appeared to affect gonad (roe) development, while depth and density did not. The relationship between macro and micro changes in the gonads was established and methods of estimating stages of gametogensis were compared.     

Systemic ethanol: selective enhancement of responses to acetylcholine and somatostatin in hippocampus

In rat hippocampal pyramidal cells tested in situ by iontophoresis of several neurotransmitters, ethanol significantly enhanced excitatory responses to acetylcholine and inhibitory responses to somatostatin-14 but had no statistically significant effect on excitatory responses to glutamate or inhibitory responses to gamma-aminobutyric acid or, in preliminary tests, to norepinephrine or serotonin. The effects of ethanol on responses to acetylcholine and somatostatin-14 may provide insight into synaptic mechanisms underlying the behavioral consequences of ethanol intoxication.     

A case study of mercury and methylmercury dynamics in a Hg-contaminated municipal wastewater treatment plant

A study of total Hg (Hg) and methylmercury (MeHg) was performed in a 40 mgd capacity municipal sewage treatment plant in which elemental Hg was used as a seal in 3 trickling filter center columns. Each seal contains several hundred kg of Hg. The seals have leaked repeatedly over time, prompting the current remediation study and ongoing replacement of the Hg seals with mechanical seals. A mass balance conducted three times while the seals were in place showed that the plant acted as a net source of both Hg and MeHg during normal operation. The average amount of Hg released in sludge plus effluent was 157 g Hg and 0.4g MeHg/d. Of this total, 138 g Hg and 0.3 g MeHg were in excess of influent wastewater, and were contributed by the WTP itself. About 95% of the total Hg was released in sludge, with only 6 to 7 g/d released to the receiving water body. However, on average, about 70% of the MeHg leaving the plant was released to the river. Effluent MeHg concentrations were 4–6 ng/L. The plant components that acted as the major sources of both total and MeHg within the plant were the trickling filters (TFs). Metallic Hg accidentally lost from the center column seals has accumulated in the rock filter media and underbedding of the tricking filters. MeHg production across the TFs was positively related to the Hg concentration in each of the TFs. A substantial fraction of the total Hg but not of MeHg was lost to sludge in each settling step. About 50% of the remaining MeHg appeared to be degraded during the tertiary aeration step.     

A Method for Determining the Ultimate Fate of Synthetic Chemicals during Composting

? Pollution control workers have proposed composting as a bioremediation method for the cleanup of contaminated soil and for the detoxification of hazardous organic chemicals. However, decomposition (mineralization to CO₂ and H₂O) may not always be enhanced by composting, and transformation products of unknown risk may accumulate during composting. This paper presents a scientifically based scheme to determine the ultimate fate of synthetic materials in a composting environment, and for studying factors that may control the degradation of specific chemicals including herbicides (e.g., substrate bioavailability, enzyme concentrations, environmental conditions).     

Black soil blindness: A new mycotoxicosis of cattle grazing Corallocytostroma-infected Mitchell grass (Astrebla spp)

A new, fatal mycotoxicosis of cattle has been recognised in north-western Australia. A feeding trial confirmed the toxicity of a previously unknown species of Corallocytostroma that grows on Mitchell grass (Astrebla spp). The disease has been colloquially named ‘black soil blindness’ because its most prominent features are its confinement to pastures on black soil, and blindness and death of affected animals. Over 500 cattle have died and considerable subclinical disease is present. Above average wet season rainfall and extended growing seasons may explain the emergence of the fungus. The disease is important because cattle production in large areas of Australia utilise Mitchell grass pastures.     

Mechanism of a reaction in vitro associated with delayed-type hypersensitivity

The cell type responsible for inhibition by antigen of migration in vitro of peritoneal exudate cells obtained from tuberculin-hypersensitive guinea pigs was studied. Exudate populations were separated into component cell types, the lymphocyte and the macrophage. Peritoneal lymphocytes from sensitive donors were the immunologically active cells in this system, the macrophages, being merely indicator cells which migrate. Sensitized peritoneal lymphocyte populations, upon interaction with specific antigen in vitro, elaborated into the medium a soluble material capable of inhibiting migration of normal exudate cells.