CO2 and water vapour exchange in four alpine herbs at two altitudes and under varying light and temperature conditions

CO₂ and water vapour exchange rates of four alpine herbs namely: Rheum emodi, R. moorcroftianum, Megacarpaea polyandra and Rumex nepalensis were studied under field conditions at 3600 m (natural habitat) and 550 m altitudes. The effect of light and temperature on CO₂ and water vapour exchange was studied in the plants grown at lower altitude. In R. moorcroftianum and R. nepalensis, the average photosynthesis rates were found to be about three times higher at 550 m as compared to that under their natural habitat. However, in M. polyandra, the CO₂ exchange rates were two times higher at 3600 m than at 550 m but in R. emodi, there were virtually no differences at the two altitudes. These results indicate the variations in the CO₂ exchange rates are species specific. The change in growth altitude does not affect this process uniformly.The transpiration rates in R. emodi and M. polyandra were found to be very high at 3600 m compared to 550 m and are attributed to overall higher stomatal conductance in plants of these species, grown at higher altitude. The mid-day closure of stomata and therefore, restriction of transpirational losses of water were observed in all the species at 550 m altitude. In addition to the effect of temperature and relative humidity, the data also indicate some endogenous rhythmic control of stomatal conductance.The temperature optima for photosynthesis was close to 30°C in M. polyandra and around 20°C in the rest of the three species. High temperature and high light intensity, as well as low temperature and high light intensity, adversely affect the net rate of photosynthesis in these species.Both light compensation point and dark respiration rate increased with increasing temperature.The effect of light was more prominent on photosynthesis than the effect of temperature, however, on transpiration the effect of temperature was more prominent than the effect of light intensity.No definite trends were found in stomatal conductance with respect to light and temperature. Generally, the stomatal conductance was highest at 20°C.The study reveals that all these species can easily be cultivated at relatively lower altitudes. However, proper agronomical methodology will need to be developed for better yields.     

Isolation of RNA from apple skin

A method has been developed for the isolation of RNA from apple skin. The method involves an adaptation of the Manning (1991) method and includes a high-salt extraction step and a final purification step through a CsCl cushion. The RNA isolated was of high quality and produced good hybridization signals in northern blot analyses.     

Effect of maternal ethanol consumption on foetal and neonatal rat hepatic protein synthesis.

Effects of maternal ethanol consumption were investigated on the rates of protein synthehsis by livers of foetal and neonatal rats both in vivo and in vitro, and on the activities of enzymes involved in protein synthesis and degradation. The rates of general protein synthesis by ribosomes in vitro studied by measuring the incorporation of [14C]leucine into ribosomal protein showed that maternal ethanol consumption resulted in an inhibition of the rates of protein synthesis by both foetal and neonatal livers from the ethanol-fed group. The rates of incorporation of intravenously injected [14C]leucine into hepatic proteins were also significantly lower in the foetal, neonatal and adult livers from the ethanol-fed group. Incubation of adult-rat liver slices with ethanol resulted in an inhibition of the incorporation of [14C]leucine into hepatic proteins; however, this effect was not observed in the foetal liver slices. This effect of externally added ethanol was at least partially prevented by the addition of pyrazole to the adult liver slices. Pyrazole addition to foetal liver slices was without significant effect on the rates of protein synthesis. Cross-mixing experiments showed that the capacity of both hepatic ribosomes and pH5 enzyme fractions to synthesize proteins was decreased in the foetal liver from the ethanol-fed group. Maternal ethanol consumption resulted in a decrease in hepatic total RNA content, RNA/DNA ratio and ribosomal protein content in the foetal liver. Foetal hepatic DNA content was not significantly affected. Ethanol consumption resulted in a significant decrease in proteolytic activity and the activity of tryptophan oxygenase in the foetal, neonatal and adult livers. It is possible that the mechanisms of inhibition of protein synthesis observed here in the foetal liver after maternal ethanol consumption may be responsible for at least some of the changes observed in 'foetal alcohol syndrome'.     

Experimental Study of the Effect of External Inductance on Pinch Characteristics and Neon Soft X-Ray Yield in Filippov-Type Plasma Focus Device

Plasma Physics Reports - So far, the detailed experimental effect of the inductance on the X-ray yield in the Filippov-type plasma focus devices has not been documented in literature. In this...     

Antifungal efficacy of Thevetia peruviana leaf extract against Alternaria solani and characterization of novel inhibitory compounds by Gas Chromatography-Mass Spectrometry analysis

Alternaria solani, a plant pathogenic fungus causes significant economical losses of potato crop. The disease is controlled primarily through some traditional methods and most commonly via the application of chemical fungicides. Fungicides treatment is not protected as chemicals pollute environment, effect health vulnerability in humans and when these harmful chemicals enter into the food chain become hazardous to all living entities. Recent efforts have focused on developing environmentally safe, long-lasting, and effective biocontrol methods for the management of plant diseases. Present research focus on screening of crude and partially purified leaf extract of Thevetia peruviana for the presence of antifungal efficacy against Alternarai solani. It was observed that 100% alcoholic crude and alcoholic fraction of partially purified extract showed maximum inhibitory activity which is due to the presence of different secondary metabolites, revealed by phytochemical screening. Active column fraction (possess best antifungal activity against Alternaria solani) was subjected to Gas Chromatography-Mass Spectrometry (GS-MS) analysis. On the basis of peaks matching of GC-MS chromatogram with available data base showed the presence of benzoic acid and oxo-benzoate in active fraction of Thevetia peruviana leaf extract which is already known chemical among the phytochemicals described for antimicrobial activity. Further research on development of herbal formulation from the same would be very helpful environment friendly approach to manage concern crop disease.     

Sit4p/PP6 regulates ER-to-Golgi traffic by controlling the dephosphorylation of COPII coat subunits

Traffic from the endoplasmic reticulum (ER) to the Golgi complex is initiated when the activated form of the GTPase Sar1p recruits the Sec23p-Sec24p complex to ER membranes. The Sec23p-Sec24p complex, which forms the inner shell of the COPII coat, sorts cargo into ER-derived vesicles. The coat inner shell recruits the Sec13p-Sec31p complex, leading to coat polymerization and vesicle budding. Recent studies revealed that the Sec23p subunit sequentially interacts with three different binding partners to direct a COPII vesicle to the Golgi. One of these binding partners is the serine/threonine kinase Hrr25p. Hrr25p phosphorylates the COPII coat, driving the membrane-bound pool into the cytosol. The phosphorylated coat cannot rebind to the ER to initiate a new round of vesicle budding unless it is dephosphorylated. Here we screen all known protein phosphatases in yeast to identify one whose loss of function alters the cellular distribution of COPII coat subunits. This screen identifies the PP2A-like phosphatase Sit4p as a regulator of COPII coat dephosphorylation. Hyperphosphorylated coat subunits accumulate in the sit4Δ mutant in vivo. In vitro, Sit4p dephosphorylates COPII coat subunits. Consistent with a role in coat recycling, Sit4p and its mammalian orthologue, PP6, regulate traffic from the ER to the Golgi complex.     

NMR investigations of structural and dynamics features of natively unstructured drug peptide – salmon calcitonin: implication to rational design of potent sCT analogs

Backbone dynamics and conformational properties of drug peptide salmon calcitonin have been studied in aqueous solution using nuclear magnetic resonance (NMR). Although salmon calcitonin (sCT) is largely unfolded in solution (as has been reported in several circular dichroism studies), the secondary H^α chemical shifts and three bond H^N–H^α coupling constants indicated that most of the residues of the peptide are populating the α‐helical region of the Ramachandran (?, ψ) map. Further, the peptide in solution has been found to exhibit multiple conformational states exchanging slowly on the NMR timescale (10²–10³ s^?1), inferred by the multiple chemical shift assignments in the region Leu4–Leu12 and around Pro23 (for residues Gln20–Tyr22 and Arg24). Possibly, these slowly exchanging multiple conformational states might inhibit symmetric self‐association of the peptide and, in part, may account for its reduced aggregation propensity compared with human calcitonin (which lacks this property). The ¹⁵N NMR‐relaxation data revealed (i) the presence of slow (microsecond‐to‐millisecond) timescale dynamics in the N‐terminal region (Cys1–Ser5) and core residues His17 and Asn26 and (ii) the presence of high frequency (nanosecond‐to‐picosecond) motions in the C‐terminal arm. Put together, the various results suggested that (i) the flexible C‐terminal of sCT (from Thr25–Thr31) is involved in identification of specific target receptors, (ii) whereas the N‐terminal of sCT (from Cys1–Gln20) in solution – exhibiting significant amount of conformational plasticity and strong bias towards biologically active α‐helical structure – facilitates favorable conformational adaptations while interacting with the intermembrane domains of these target receptors. Thus, we believe that the structural and dynamics features of sCT presented here will be useful guiding attributes for the rational design of biologically active sCT analogs. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Development of polymorphic EST-SSR markers and their applicability in genetic diversity evaluation in Rhododendron arboreum

Molecular Biology Reports - The genus Rhododendron, known for large impressive flowers is widely distributed throughout the world. Rhododendrons have limited genetic information, despite of...     

New national and regional bryophyte records, 46

Abstract

Bryophyte biomass and diversity vary strongly with altitude in the tropics. Low abundance and low species numbers in lowland rain forests are most likely due to reduced diurnal activity times combined with high nocturnal respiration rates at high temperatures. This may exclude many montane species from the warm lowlands. However, an alternative hypothesis explains the observed pattern, namely a limited desiccation tolerance of montane species, precipitation being more concentrated but less frequent in most lowland forests compared to montane cloud forests. To test this hypothesis, we studied the desiccation tolerance of four montane and four lowland bryophyte species. The effects of prolonged drought were quantified with chlorophyll fluorescence (F_v/F_m) and the extent of electrolyte leakage. Both montane and lowland species survived dry periods of ≧80 days, which far exceeds the duration of dry periods in the wet lowland tropics. We can thus exclude intolerance to long dry spells as an explaination for the absence of the tested montane species in the lowlands. We should continue to focus on other mechanisms to explain the altitudinal gradient of bryophyte abundance and diversity in the tropics, in order to understand this pattern, as well as to predict future trends under climatic warming.