Effect of salt-stress on translocation of photosynthates in pigeon-pea

Summary An investigation was carried out in order to study the effect of salts namely NaC1 and Na₂SO₄ on the rate of translocation of photosynthates in pigeonpea, at the pod filling stage. At the concentration of 10 EC NaC1 only 17% of the¹⁴C assimilates are translocated from the source leaf to the other parts of the plant. Out of this pods receive about 8%. On the other hand even at a concentration of 15 EC Na₂SO₄ about 30% of the total¹⁴C assimilates get translocated and out of this pods receive about 12%. From this it may be concluded that under salt-stress conditions the rate of translocation of photosynthates is adversely affected and between the two salts, NaC1 was discovered to have a marked inhibitory effect.     

Influence of silver nanoparticles on the enhancement and transcriptional changes of glucosinolates and phenolic compounds in genetically transformed root cultures of Brassica rapa ssp. rapa

Bioprocess and Biosystems Engineering - Glucosinolates (GSLs) and phenolic compounds (PCs) are biologically active and involved in the defense reaction of plants; these compounds have a beneficial...     

IgG subclass specificity to C1q determined by surface plasmon resonance using Protein L capture technique

Recombinant monoclonal antibodies (mAbs) have become an important category of biological therapeutics. mAbs share the same structures and biological functions as endogenous IgG molecules. One function is complement-dependent cytotoxicity (CDC) initiation by binding of C1q. Traditionally, ELISA methods have been utilized to measure C1q binding. A new robust capture method was established in this study to measure the binding affinity of C1q to antibodies by surface plasmon resonance (SPR). The utility of this method was demonstrated by determination of the difference in IgG subclass specificity of C1q binding.     

Direct Regulation of Osteocytic Connexin 43 Hemichannels through AKT Kinase Activated by Mechanical Stimulation

Connexin (Cx) 43 hemichannels in osteocytes are thought to play a critical role in releasing bone modulators in response to mechanical loading, a process important for bone formation and remodeling. However, the underlying mechanism that regulates the opening of mechanosensitive hemichannels is largely unknown. We have recently shown that Cx43 and integrin α5 interact directly with each other, and activation of PI3K appears to be required for Cx43 hemichannel opening by mechanical stimulation. Here, we show that mechanical loading through fluid flow shear stress (FFSS) increased the level of active AKT, a downstream effector of PI3K, which is correlated with the opening of hemichannels. Both Cx43 and integrin α5 are directly phosphorylated by AKT. Inhibition of AKT activation significantly reduced FFSS-induced opening of hemichannels and disrupted the interaction between Cx43 and integrin α5. Moreover, AKT phosphorylation on Cx43 and integrin α5 enhanced their interaction. In contrast to the C terminus of wild-type Cx43, overexpression of the C-terminal mutant containing S373A, a consensus site previously shown to be phosphorylated by AKT, failed to bind with α5 and hence could not inhibit hemichannel opening. Together, our results suggest that AKT activated by FFSS directly phosphorylates Cx43 and integrin α5, and Ser-373 of Cx43 plays a predominant role in mediating the interaction between these two proteins and Cx43 hemichannel opening, a crucial step to mediate the anabolic function of mechanical loading in the bone.     

Dolichos yellow mosaic virus belongs to a distinct lineage of Old World begomoviruses; its biological and molecular properties

Dolichos yellow mosaic disease (DYMD) affects the production of dolichos in South Asia. Diseased plants produce characteristic bright yellow mosaic patches on the leaves and early infections cause reductions in yield. The putative dolichos yellow mosaic virus (DoYMV) was transmitted poorly (maximum 18.3% transmission) by the whitefly, Bemisia tabaci. DoYMV has a narrow host range and infected only Lablab purpureus and L. purpureus var. typicum out of the 36 species tested. Virus was detected using monoclonal antibodies in a triple‐antibody sandwich enzyme‐linked immunosorbent assay and by PCR. Complete DNA‐A components of DoYMV isolates from Mysore and Bangalore, South India, were sequenced, but several attempts to identify DNA‐B and DNA‐β were unsuccessful. DoYMV isolates shared DNA‐A nucleotide identities of 92.5–95.3% with previously described isolates from North India and Bangladesh. They were most similar to mungbean‐infecting begomoviruses at 61.6–64.4% of DNA‐A nucleotide identities. Phylogenetic analyses of DNA‐A sequences grouped the dolichos‐infecting and mungbean‐infecting begomoviruses into a distinct cluster away from begomoviruses infecting non‐leguminous plants in the Indian subcontinent. Antigenically, legume‐infecting begomoviruses were most similar to each other compared with non‐legume viruses. Collectively, these results indicate that legume‐infecting begomoviruses in the Indian subcontinent belonged to a distinct lineage of Old World begomoviruses.     

Increase in Nitrate Reductase Activity in Bean Leaves by Light Involves a Regulator Protein

Nitrate reductase activity, assayed either in vivo or in vitro was considerably higher in bean (Phaseolus vulgaris L.) leaves from 7-day-old light grown seedlings than those from dark grown, both in the absence as well as presence of nitrate. Cytochrome c reductase activity was however similar in both regimes, while peroxidase was lower in light than in dark. The light stimulated increase in nitrate reductase activity in leaf segments from dark grown seedlings was inhibited by cycloheximide, DNP, chloramphenicol, and sodium tungstate and was unaffected by lincomycin and DCMU. Under similar conditions, the increase in total chlorophyll was inhibited completely by cycloheximide and DNP, partially by chloramphenicol and lincomycin, and was unaffected by tungstate and DCMU. A supply of 1~5 mm reduced glutathione increased enzyme activity in the dark and also to some extent in light. The substrate induction of enzyme activity started after a lag of one hr in light or dark and continued for either 5 hr in the dark or 8 hr in light. Two proteinaceous inhibitors (Factors I and II) of nitrate reductase were isolated by ammonium sulfate precipitation and Sephadex gel filtration. The amount of Factor I was higher in the dark than in light. The amount and activity of Factor II was however, almost equal in light and dark. The inhibition of enzyme activity by these inhibitors increased with their concentration. It is proposed that light increases nitrate reductase activity by decreasing the amount of a nitrate reductase inhibitor.     

Female preference for blue in Japan blue guppies (Poecilia reticulata)

Guppies (Poecilia reticulata) are widely used as a model species in mate choice studies. Although native to South America, guppies have been introduced to natural water bodies in disparate regions of the globe. Here, for the first time, we examine guppies from one such introduced population in Japan where males have evolved a predominantly blue color pattern. Previous studies of wild-type guppies have shown blue to play a relatively minor role in the mate choice decisions of females compared to other traits, such as orange, and the importance of blue is not universally supported by all studies. The Japanese population therefore presents an ideal opportunity to re-examine the potential significance of blue as a mate choice cue in guppies. Mate choice experiments, in which female Japan blue guppies were given a choice between pairs of males that differed in their area of blue coloration but were matched for other traits, revealed that females prefer males with proportionately larger amounts of blue in their color patterns. We discuss possible factors, including sexual and ecological selection, which may have led to the evolution of unusually large areas of blue at the expense of other colors in Japan blue guppies. However, further studies are needed to distinguish between these scenarios.