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.     

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.     

Precautions when using opioid agonists for induction of anesthesia.

Opioids produce unpredictable anesthesia that is associated with poor muscle relaxation, prolonged onset, and relatively difficult intubation. They often induce bradycardia, which must be countered with atropine or glycopyrrolate, and hypoventilation, which requires ventilatory support. Return to consciousness is often delayed, making postoperative assessment of the patient's condition difficult. Finally opioid induction is relatively expensive compared with other anesthetic induction regimens.     

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.     

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.     

Physiological Analysis of Yield Variation in Mungbean (Vigna radiata [Roxb.] Wilczek)

Two mungbean varieties, Guj-1 and PIMS-1 differing in their productivity potential, were examined to investigate their photosynthetic system at various stages of growth in relation to yield with two different dates of sowing. Vertical leaves were found to be beneficial. On the other hand, excessive leaf area during the later stages of growth may be detrimental to yield. Lower LAD at seedling stage and overall high NAR values may be reflected in higher grain yield. NAR declined as season progressed and this, in turn, may be related with increase in LAI. The grain yield was considerably more at the first date of sowing as compared to second date of sowing, the effect was being more pronounced in var. PIMS-1 . Various environmental factors recorded at two different dates of sowing and at various stages of growth indicated that these factors may have influenced the yield potential at two different dates of sowing.     

Response time of broiler chickens to cimaterol: meat tenderness, muscle composition fiber size, and carcass characteristics.

The response time to cimaterol (CIM), a beta-adrenergic agonist, by broiler chickens for carcass characteristics, muscle composition, muscle fiber size, catheptic enzyme activity, and tenderness was determined. Two trials were conducted in which chickens were fed a control diet (CON) containing 0 ppm of CIM or a diet containing 1 ppm of CIM. Trial 1 consisted of 55, 31-d-old broiler chickens individually fed for up to 48 h. At 0, 6, 12, 18, 24, and 48 h, five CON and five CIM-fed chickens were killed. Trial 2 consisted of 160, 33-d-old broiler chickens group-fed for up to 14 d. At 2, 4, 6, 8, 10, 12, and 14 d, 10 CON and 10 CIM-fed chickens were killed. The breast muscle (BM) and leg muscle (LM) weight, cathepsin B and L activities, DNA, RNA, and protein concentration, and BM shear force value (SFV) were measured in both trials. Thigh muscle (TM) SFV were measured in Trial 2 only. Fiber size of BM was measured (five birds per treatment) at d 2, 6, 10, and 14. In Trial 1, BM weight and SFV were lower in CIM-fed birds at 6 h (P less than .05). In Trial 2 BM SFV were higher at d 8 (P = .06) and d 10 (P less than .05) in CIM-fed chickens. The SFV of CIM-fed chickens were higher at d 4, 8, 10, 12, and 14 (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)