A novel approach to studying the effects of temperature on soil biogeochemistry using a thermal gradient bar

The temperature dependence of chemical reaction rates and microbial metabolism mean that temperature is a key factor regulating soil trace gas emissions and hydrochemistry. Here we evaluated a novel approach for studying the thermal response of soils, by examining the effects of temperature on gas emissions and hydrochemistry in (a) peat and (b) soil from a Sitka spruce plantation. A thermal gradient was applied along an aluminium bar, allowing soil to be incubated contemporaneously from 2 to 18 °C. The approach demonstrated clear differences in the biogeochemical responses of the two soil types to warming. The peat showed no significant emission of CH₄ at temperatures below 6 °C, while above 6 °C, a marked increase in the rate of release was apparent up to 15 °C (Q₁₀ = 2.5) with emissions being similar between 15 and 18 °C. Conversely, CH₄ emissions from the forest soil did not respond to warming. Nitrate availability in the peat decreased by 90% between 2 and 18 °C (P < 0.01), whereas concentrations in the forest soil did not respond. Sulphate availability in the peat decreased significantly with warming (60%, P < 0.01), while the forest soil showed the opposite response (a 30% increase, P < 0.01). Conventionally, thermal responses are studied by incubating individual soil samples at different temperatures, involving lengthy preparation and facilities to incubate samples at different temperatures simultaneously. Data collected on a given thermal response is usually limited and thus interpolated or extrapolated. The thermal gradient method overcomes these problems, is simple and flexible, and can be adapted for a wide range of sample types (not confined to soil). Such apparatus may prove useful in the optimization of management practices to mitigate the effects of climate change, as thermal responses will differ depending on land use and soil type.     

Contribution of Metallogenium-Siderococcus bacteria to the postvolcanic transformation of igneous material (Kamchatka)

The transformation of recent igneous rock occurs with participation of microorganisms associated with the deposition of iron and aluminum on their cell surface. An identity of morphological structures was found in the microorganisms in both cases, and this fact counts in favor of their similarity and wide distribution in the rock being transformed. The polymorphous acid-resisting organism identified by our studies was tentatively classified with the Metallogenium-Siderococcus group.     

Osteosarcoma of the distal femur, combined with multiple bone infarcts: the case of a 10-year-old poodle

A ten-year-old female poodle was presented for left hindlimb lameness. Radiographically, irregular intramedullary densities of long bones (bone infarcts) and a lytic lesion in the left distal femur were detected. Two years after the first examination, the lesions in the distal femur were definitely identified as osteosarcoma and the dog was euthanized. Pathological and histological changes of the bone infarcts as well as of the osteosarcoma are described. Regarding bibliographical data, occurrence and aetiopathogenesis of osteosarcoma associated with multifocal bone infarction in man and dog are discussed.     

Otodectes cynotis infestation of dogs and cats: biology of the agent, epidemiology, pathogenesis and diagnosis and case description of generalized mange in dogs

A review on the biology, epidemiology, pathogenesis and diagnosis of Otodectes cynotis in dogs and cats is presented. Additionally, three cases of generalized otodectic mange in dogs are described.     

Pasteurella haemolytica A1 and Bovine Respiratory Disease: Pathogenesis

The severe fibrinonecrotic pneumonia associated with pneumonic pasteurellosis usually results from colonization of the lower respiratory tract by Pasteurella haemolytica biotype A, serotype 1(A1). Despite recent research efforts, the authors lack a detailed understanding of the interactions and host response to P. haemolytica in the respiratory tract. The authors hypothesize that management and environmental stress factors or viral infection alters the upper respiratory tract (URT) epithelium allowing P. haemolytica to colonize the epithelium. Once the URT is colonized, large numbers of organisms enter the lung where they interact with alveolar macrophages. Endotoxin, released from the bacteria, crosses the alveolar wall where it activates pulmonary intravascular macrophages, endothelium, neutrophils, lymphocytes, platelets, complement, and Hageman factor leading to complex interactions of cells and mediators. It is the progression of this inflammatory response with neutrophil influx that is ultimately responsible for the pulmonary injury. Leukotoxin is a major virulence factor of P. haemolytica that allows it to survive by destroying phagocytic cells. At subcytolytic concentrations it may also enhance the inflammatory response by activating cells to produce mediators and release reactive oxygen metabolites and proteases.     

Characteristics of cytotoxic cells induced by Toxoplasma lysate antigen in mouse spleen.

Spleen cells from Toxoplasma lysate antigen (TLA)-sensitized BALB/c mice showed the strong cytotoxic activity against both natural killer (NK)-sensitive cells (YAC-1 and RL male-1) and NK-insensitive cells (P-815), when incubated with TLA or recombinant human IL-2 (rhIL-2). The increment of TLA concentration in culture medium increased the cytotoxic activity. Treatment of effector cells; spleen cells from TLA-sensitized mice incubated with TLA, with anti-asialo GM1 or anti-Thy-1 plus complement inhibited the cytotoxic activity of effector cells, whereas treatment with anti-mouse Lyt-2.2 serum plus complement had no effect on the cytotoxic activity. Treatment of spleen cells from TLA-sensitized mice with anti-asialo GM1 and/or anti-Thy-1 plus complement inhibited cytotoxic activities of effector cells. These results suggested that spleen cells sensitized with TLA both in vivo and in vitro were asialo GM1 positive and Thy-1 positive, and the majority of cytotoxic cells induced by TLA were similar to lymphokine-activated killer (LAK) cells induced by IL-2.     

Oxidative damage to the membrane of canine erythrocytes with inherited high Na, K-ATPase activity.

Oxidative damage to the membrane in canine erythrocytes with inherited high Na, K-ATPase activity (HK cells) was compared with that in normal canine cells (LK cells). When 30 mM beta-acetylphenylhydrazine (APH) was applied to HK and LK cells, lipid peroxidation and hemoglobin denaturation occurred. Lipid peroxidation determined from malondialdehyde (MDA) formation was significantly lower in HK than in LK cells so far as endogenous glutathione (GSH) concentration was maintained at appropriate levels. With the depletion of GSH, MDA formation was accelerated and difference between HK and LK cells was not significant. Denatured hemoglobin bound to the membrane protein was less in HK than in LK cells. During incubation with APH, osmotic fragility increased markedly in LK cells, while HK cells showed very little change. The amounts of total lipid, total and free cholesterol, glycolipid, phospholipid and fatty acids were essentially the same in both cell types. Fatty acid compositions showed very small differences. The membrane of HK cells thus appear to have greater protection against oxidative damage induced by APH, owing to the presence of excess GSH in HK cells. The capability of HK cells to withstand oxidative damage would not be due to differences in membrane lipid compositions.     

Prevention of estrus in the queen with chlormadinone acetate administered orally.

The possibility of estrus prevention in the queen by the oral administration of chlormadinone acetate was examined. The animals used were 29 mature and 15 immature queens. For 16 mature females, 4-12.5 mg was given daily by mouth for 7 days every 3 months. Ten of the 16 queens given this treatment came into estrus within 4 months of the first treatment. For 28 females including the immature, 2-12.5 mg was given once a week throughout the experiment. This treatment prevented estrous activity for at least 1 year. In the queens in this study, the side effects were not observed excepting an increase in body weight during treatment. Our results showed that oral administration of this drug weekly is safe and reliable for long-range prevention of estrus in queens.     

Use of autogenous cancellous bone graft for treatment of osteolytic defects in the phalanges of three cattle.

Osteolytic defects were detected radiographically in the distal sesamoid bone of a 16-month-old Bralers heifer, in the middle phalanx of a 14-month-old American Gray Brahman bull, and in the distal phalanx of a 3-year-old American Gray Brahman bull. The articular cartilage was damaged in each animal because of osteolysis or pathologic fracture. After each animal was anesthetized and positioned in lateral recumbency, the lesions were curetted and packed with cancellous bone harvested from the same animal's tuber coxae. Basic postoperative management involved stall rest and immobilization of the graft site with a fiberglass cast (42 to 79 days), after which a support bandage was used for approximately 2 weeks. Recurrence of lameness has not been observed in these animals for 60 months, 58 months, and 21 months, respectively. These cases exemplify the benefit of using an autogenous cancellous bone graft for treatment of severe osteolysis of a digit in cattle.