Occurrence of Diaphanosoma excisum (Sars) on a sandy beach at Balramgari (Orissa), India

The occurrence of Diaphanosoma excisum (Sars), a freshwater cladoceran, in benthic samples of an intertidal sandy beach is reported. Population density was seasonal. A relatively high density was recorded from June to September (south-west monsoon season) with a maximum (46 ind 10 cm^–2) in September at a depth of 10–15 cm of sediment. A sudden decline occurred during north-east monsoon (October to January), and in the fair season (February to May), the cladocerans disappeared. Mean density varied (P<0.001) with sediment depth and season and showed a contagious dispersion. Abundance was negatively correlated with salinity (r = –0.76) but positively with POC (r =0.79) and mean grain size of the sediment (r = 0.93). The density of D. excisum was highest in fine sand.     

Ageing, gerontogenes, and hormesis

Evolutionary theories of ageing and longevity argue against the existence of specific genes that cause ageing. However, genes whose altered activity influences ageing and longevity, may be termed gerontogenes. Several putative gerontogenes have been identified in various ageing systems, including the Drosophila, budding yeast, nematodes and cells in culture. Since ageing is characterized by a progressive failure of maintenance and repair, it is reasoned that genes involved in homeodynamic repair pathways are the most likely candidate gerontogenes. A promising approach for the identification of critical gerontogenic processes is hormesis-like positive effects of stress. Stimulation of various repair pathways by mild stress has significant effects on delaying the onset of various age-associated alterations in cells, tissues and organisms.     

Alterations in osteoclast morphology following osteoprotegerin administration in the magnesium-deficient mouse

In the present study, we used osteoprotegerin (OPG), which blocks osteoclastogenesis, to correct and thus explain the hypercalcemia that is seen during dietary Mg deficiency in the mouse. Control and Mg-deficient mice received injections for 12 days of either OPG or vehicle only. Serum Ca was similar in Mg-deficient mice treated with OPG and in control mice receiving OPG (9.2±0.3 mg/dl vs. 9.2±0.5). Both groups had significantly higher serum Ca than controls or Mg-deficient animals receiving vehicle alone. Surprisingly, Mg-depleted mice that received OPG in doses that inhibit osteoclastic bone resorption remained hypercalcemic. Because mature osteoclasts still present in the marrow might be hyperactive, we examined osteoclast morphology at the light microscopic and ultrastructural level. Light microscopic examination of trabecular bone showed few osteoclasts in OPG-treated mice. Ultrastructural examination revealed that osteoclasts in OPG-treated mice have decreased contact with the endosteal bone surface and absence of a ruffled border. Because the morphology of the existing pool of mature osteoclasts did not enhance resorption, another mechanism, such as increased intestinal absorption of Ca in Mg-deficient mice, likely contributes to the hypercalcemia observed during Mg deficiency.     

A major terminal drought tolerance QTL of pearl millet is also associated with reduced salt uptake and enhanced growth under salt stress

The performance of a major quantitative trait locus (QTL) of terminal drought tolerance (DT) of pearl millet was assessed under salt stress. The test-cross hybrids of the QTL donor parent (drought tolerant, PRLT 2/89-33), QTL recipient parent (drought sensitive, H 77/833-2), and a set of six near isogenic lines introgressed with a terminal DT-QTL (QTL-NILs) were evaluated for germination and seedling emergence at 7 days after sowing (DAS) in Petri plates at four salinity levels, and at vegetative (24 DAS) and maturity stages at three salinity and alkalinity levels. Na⁺ and K⁺ accumulation, their compartmentation in different plant parts, and their effects on growth and yield parameters were evaluated. The DT-QTL donor parent and QTL-NILs accumulated less Na⁺ in shoot parts at seedling, vegetative and maturity stages, and also partitioned the accumulated Na⁺ more into nodes and internodes and less into leaves than the drought-sensitive recurrent parent. The pattern of reduced salt accumulation in the drought-tolerant parent and QTL-NILs was consistently associated with better growth and productivity in saline and alkaline treatments. It is concluded that the DT-QTL contributed by PRLT 2/89-33 exerted favourable effects on growth and productivity traits under salt stress by limiting Na⁺ accumulation in leaves.     

Land use impacts on physical properties of 28 years old reclaimed mine soils in Ohio

Reclamation enhances soil quality by improving physical and chemical properties, which helps in restoration of mine soils. Evaluation of the effects of post-reclamation land uses on physical and chemical properties of mine soils helps to identify suitable land uses for mining companies. The objectives of this study were to evaluate the effects of post-reclamation land uses (e.g., forest, hay and pasture) on selected physical properties of soil in relation to undisturbed forest and agricultural land use. Soil samples were collected from the 0- to 5-, 5- to 15- and 15- to 30-cm depths in order to determine particle size distribution, bulk density, water-stable aggregates, mean-weight diameter and soil moisture retention. Cone index and infiltration rate were determined at soil surface. After 28 years of reclamation, bulk density in the surface layer of all land uses in the reclaimed mine soil (RMS) was similar to that of undisturbed forest (1.1 Mg m⁻³) but lower than that of agricultural soils (1.3 Mg m⁻³). However, soil bulk density at lower depths was not affected. The cone index was higher in the RMS-pasture (2.6 MPa) than the RMS-forest (1.4 MPa) and RMS-hay (1.5 MPa) due to the trampling effect of grazing animals. The water-stable aggregates (>2 mm), of 5–8 mm aggregates, were higher in RMS-forest by 24%, 90%, 66%, and under RMS-hay by 13%, 74%, 43% for the 0- to 5-, 5- to 15-, and 15- to 30-cm depths, respectively, than that under undisturbed forest. The mean-weight diameter (0- to 30-cm) of aggregates under RMS-forest and RMS-hay were higher than that under undisturbed forest by 41% and 27%, respectively. The initial infiltration rates at 5 min in RMS under forest, hay and pasture were less by 20%, 53% and 85%, respectively, than that under undisturbed forest (19.3 cm min⁻¹). The reclamation of mine soils with forest and hay improved surface soil bulk density and cone index, and enhanced water infiltration capacity and water-stable aggregates at the lower depths. Therefore, establishment of forest and hay should be encouraged in the RMS.     

Digging deeper: A holistic perspective of factors affecting soil organic carbon sequestration in agroecosystems

The global magnitude (Pg) of soil organic carbon (SOC) is 677 to 0.3‐m, 993 to 0.5‐m, and 1,505 to 1‐m depth. Thus, ~55% of SOC to 1‐m lies below 0.3‐m depth. Soils of agroecosystems are depleted of their SOC stock and have a low use efficiency of inputs of agronomic yield. This review is a collation and synthesis of articles published in peer‐reviewed journals. The rates of SOC sequestration are scaled up to the global level by linear extrapolation. Soil C sink capacity depends on depth, clay content and mineralogy, plant available water holding capacity, nutrient reserves, landscape position, and the antecedent SOC stock. Estimates of the historic depletion of SOC in world soils, 115–154 (average of 135) Pg C and equivalent to the technical potential or the maximum soil C sink capacity, need to be improved. A positive soil C budget is created by increasing the input of biomass‐C to exceed the SOC losses by erosion and mineralization. The global hotspots of SOC sequestration, soils which are farther from C saturation, include eroded, degraded, desertified, and depleted soils. Ecosystems where SOC sequestration is feasible include 4,900 Mha of agricultural land including 332 Mha equipped for irrigation, 400 Mha of urban lands, and ~2,000 Mha of degraded lands. The rate of SOC sequestration (Mg C ha^?1 year^?1) is 0.25–1.0 in croplands, 0.10–0.175 in pastures, 0.5–1.0 in permanent crops and urban lands, 0.3–0.7 in salt‐affected and chemically degraded soils, 0.2–0.5 in physically degraded and prone to water erosion, and 0.05–0.2 for those susceptible to wind erosion. Global technical potential of SOC sequestration is 1.45–3.44 Pg C/year (2.45 Pg C/year).     

DNA methylation regulated microRNAs in HPV-16-induced head and neck squamous cell carcinoma (HNSCC)

Molecular and Cellular Biochemistry - Epigenetic modifications have been reported to play an important role in regulating gene expression and these modifications become critical when they have a...     

Hydrologic sources of carbon cycling uncertainty throughout the terrestrial–aquatic continuum

Linking hydrologic interactions with global carbon cycling will reduce the uncertainty associated with scaling-up empirical studies and facilitate the incorporation of terrestrial–aquatic linkages within global and regional change models. Much of the uncertainty in estimates of carbon fluxes associated with precipitation and hydrologic transport results from the extensive spatial and temporal heterogeneity in both intrinsic functioning and anthropogenic modification of hydrological cycles. To better understand this variation we developed a landscape ecological approach to coupled hydrologic–carbon cycling that merges local mechanisms with multiple-scale spatial heterogeneity. This spatially explicit framework is applied to examine variability in hydrologic influences on carbon cycling along a continental scale water availability gradient with an explicit consideration of human sources of variability. Hydrologic variation is an important component of the uncertainty in carbon cycling; accounting for this variation will improve understanding of current conditions and projections of future ecosystem responses to global change.     

Function of calmodulin in postsynaptic densities. II. Presence of a calmodulin- activatable protein kinase activity

Because the calmodulin in postsynaptic densities (PSDs) activates a cyclic nucleotide phosphodiesterase, we decided to explore the possibility that the PSD also contains a calmodulin-activatable protein kinase activity. As seen by autoradiographic analysis of coomassie blue-stained SDS polyacrylamide gels, many proteins in a native PSD preparation were phosphorylated in the presence of [γ-(32)P]ATP and Mg(2+) alone. Addition of Ca(2+) alone to the native PSD preparation had little or no effect on phosphorylation. However, upon addition of exogenous calmodulin there was a general increase in background phosphorylation with a statistically significant increase in the phosphorylation of two protein regions: 51,000 and 62,000 M(r). Similar results were also obtained in sonicated or freeze thawed native PSD preparations by addition of Ca(2+) alone without exogenous calmodulin, indicating that the calmodulin in the PSD can activate the kinase present under certain conditions. The calmodulin dependency of the reaction was further strengthened by the observed inhibition of the calmodulin-activatable phosphorylation, but not of the Mg(2+)-dependent activity, by the Ca(2+) chelator, EGTA, which also removes the calmodulin from the structure (26), and by the binding to calmodulin of the antipsychotic drug chlorpromazine in the presence of Ca(2+). In addition, when a calmodulin-deficient PSD preparation was prepared (26), sonicated, and incubated with [γ-(32)P]ATP, Mg(2+) and Ca(2+), one could not induce a Ca(2+)-stimulation of protein kinase activity unless exogenous calmodulin was added back to the system, indicating a reconstitution of calmodulin into the PSD. We have also attempted to identify the two major phosphorylated proteins. Based on SDS polyacrylamide gel electrophoresis, it appears that the major 51,000 M(r) PSD protein is the one that is phosphorylated and not the 51,000 M(r) component of brain intermediate filaments, which is a known PSD contaminant. In addition, papain digestion of the 51,000 M(r) protein revealed multiple phosphorylation sites different from those phosphorylated by the Mg(2+)-dependent kinase(s). Finally, although the calmodulin-activatable protein kinase may phosphorylate proteins I(a) and I(b), the cyclic AMP-dependent protein kinase, which definitely does phosphorylate protein I(a) and I(b) and is present in the PSD, does not phosphorylate the 51,000 and 62,000 M(r) proteins, because specific inhibition of this kinase has no effect on the levels of the phosphorylation of these latter two proteins.