The temperature sensitivity of soil: microbial biodiversity,growth, and carbon mineralization

Microorganisms drive soil carbon mineralization and changes in their activity with increased temperature could feedback to climate change. Variation in microbial biodiversity and the temperature sensitivities (Q₁₀) of individual taxa may explain differences in the Q₁₀ of soil respiration, a possibility not previously examined due to methodological limitations. Here, we show phylogenetic and taxonomic variation in the Q₁₀ of growth (5–35 °C) among soil bacteria from four sites, one from each of Arctic, boreal, temperate, and tropical biomes. Differences in the temperature sensitivities of taxa and the taxonomic composition of communities determined community-assembled bacterial growth Q₁₀, which was strongly predictive of soil respiration Q₁₀ within and across biomes. Our results suggest community-assembled traits of microbial taxa may enable enhanced prediction of carbon cycling feedbacks to climate change in ecosystems across the globe.Subject terms: Biogeochemistry, Ecosystem ecology, Soil microbiology     

A Serological Survey of Ruminant Livestock in Kazakhstan During Post-Soviet Transitions in Farming and Disease Control

The results of a serological survey of livestock in Kazakhstan, carried out in 1997–1998, are reported. Serum samples from 958 animals (cattle, sheep and goats) were tested for antibodies to foot and mouth disease (FMD), bluetongue (BT), epizootic haemorrhagic disease (EHD), rinderpest (RP) and peste des petits ruminants (PPR) viruses, and to Brucella spp. We also investigated the vaccination status of livestock and related this to changes in veterinary provision since independence in 1991. For the 2 diseases under official surveillance (FMD and brucellosis) our results were similar to official data, although we found significantly higher brucellosis levels in 2 districts and widespread ignorance about FMD vaccination status. The seroprevalence for BT virus was 23%, and seropositive animals were widespread suggesting endemicity, despite the disease not having being previously reported. We found a few seropositives for EHDV and PPRV, which may suggest that these diseases are also present in Kazakhstan. An hierarchical model showed that seroprevalence to FMD and BT viruses were clustered at the farm/village level, rather than at a larger spatial scale. This was unexpected for FMD, which is subject to vaccination policies which vary at the raion (county) level.     

Randomised controlled trial of gabapentin in Complex Regional Pain Syndrome type 1 [ISRCTN84121379]

Background  

Complex Regional Pain Syndrome type one (CRPS I) or formerly Reflex Sympathetic Dystrophy (RSD) is a disabling syndrome, in which a painful limb is accompanied by varying symptoms. Neuropathic pain is a prominent feature of CRPS I, and is often refractory to treatment. Since gabapentin is an anticonvulsant with a proven analgesic effect in various neuropathic pain syndromes, we sought to study the efficacy of the anticonvulsant gabapentin as treatment for pain in patients with CRPS I.     

Reliability of leg muscle electromyography in vertical jumping

In this study we aimed to determine the reliability of the surface electromyography (EMG) of leg muscles during vertical jumping between two test sessions, held 2 weeks apart. Fifteen females performed three maximal vertical jumps with countermovement. The displacement of the body centre of mass (BCM), duration of propulsion phase (time), range of motion (ROM) and angular velocity of the knee and surface EMG of four leg muscles (rectus femoris, vastus medialis. biceps femoris and gastrocnemius) were recorded during the jumps. All variables were analysed throughout the propulsion and mid-propulsion phases. Intraclass correlation coefficients (ICC) for the rectus femoris, vastus medialis, biceps femoris and gastrocnemius were calculated to be 0.88, 0.70, 0.24 and 0.01, respectively. BCM, ROM and time values all indicated ICC values greater than 0.90, and the mean knee angular velocity was slightly lower, at 0.75. ICCs between displacement of the BCM and integrated EMG (IEMG) of the muscles studied were less than 0.50. The angular velocity of the knee did not correlate well with muscle activity. Factors that may have affected reliability were variations in the position of electrode replacement, skin resistance, cross-talk between muscles and jump mechanics. The results of this study suggest that while kinematic variables are reproducible over successive vertical jumps, the degree of repeatability of an IEMG signal is dependent upon the muscle studied.     

Tissue factor alters the pK(a) values of catalytically important factor VIIa residues

Blood coagulation is triggered when the serine protease factor VIIa (fVIIa) binds to cell surface tissue factor (TF) to form the active enzyme-cofactor complex. TF binding to fVIIa allosterically augments the enzymatic activity of fVIIa toward macromolecular substrates and small peptidyl substrates. The mechanism of this enhancement remains unclear. Our previous studies have indicated that soluble TF (sTF; residues 1-219) alters the pH dependence of fVIIa amidolytic activity (Neuenschwander et al. (1993) Thromb. Haemostasis 70, 970), indicating an effect of TF on critical ionizations within the fVIIa active center. The pKa values and identities of these ionizable groups are unknown. To gain additional insight into this effect, we have performed a detailed study of the pH dependence of fVIIa amidolytic activity. Kinetic constants of Chromozym t-PA (MeSO(2)-D-Phe-Gly-Arg-pNA) hydrolysis at various pH values were determined for fVIIa alone and in complex with sTF. The pH dependence of both enzymes was adequately represented using a diprotic model. For fVIIa alone, two ionizations were observed in the free enzyme (pK(E1) = 7.46 and pK(E2) = 8.67), with at least a single ionization apparent in the Michaelis complex (pK(ES1) similar 7.62). For the fVIIa-TF complex, the pK(a) of one of the two important ionizations in the free enzyme was shifted to a more basic value (pK(E1) = 7.57 and pK(E2) = 9.27), and the ionization in the Michaelis complex was possibly shifted to a more acidic pH (pK(ES1) = 6.93). When these results are compared to those obtained for other well-studied serine proteases, K(E1) and K(ES1) are presumed to represent the ionization of the overall catalytic triad in the absence and presence of substrate, respectively, while K(E2) is presumed to represent ionization of the alpha-amino group of Ile(153). Taken together, these results would suggest that sTF binding to fVIIa alters the chemical environment of the fVIIa active site by protecting Ile(153) from deprotonation in the free enzyme while deprotecting the catalytic triad as a whole when in the Michaelis complex.     

Intravenous angiotensin induces brain c-fos expression and vasopressin release in the near-term ovine fetus

The effect of intravenous angiotensin II (ANG II) on fetal brain c-fos expression and arginine vasopressin (AVP) release was studied in the near-term ovine fetus. Fetuses with chronically implanted catheters received an intravenous infusion of ANG II or saline. Fetal plasma AVP concentrations were significantly increased after the peripheral administration of ANG II, with peak levels (3-fold) at 30 min after the intravenous infusion. There was no change in fetal plasma osmolality, sodium, and hematocrit levels between the control and experimental groups or between the periods before and after the infusion of ANG II. Intravenous ANG II administration induced Fos immunoreactivity (Fos-IR) in the circumventricular organs and the median preoptic nucleus of the fetal brain. Fos-IR was also demonstrated in the fetal supraoptic nuclei (SON). Double labeling demonstrated that the AVP-containing neurons in the SON were expressing c-fos in response to intravenous ANG II. These results indicate that the peripheral ANG II in the fetus may play a significant role in stimulating the central hypothalamic-neurohypophysial system during late gestation. It supports the hypothesis that circulating ANG II may act at the fetal AVP neurons in the hypothalamus in body fluid balance via the circumventricular organs, which are situated outside the blood-brain barrier, and the central neural pathway between these two brain structures has been relatively established in utero, at least at near-term.