P-selectin and CD63 use different mechanisms for delivery to Weibel-Palade bodies

The biogenesis of endothelial-specific Weibel-Palade bodies (WPB) is poorly understood, despite their key role in both haemostasis and inflammation. Biogenesis of specialized organelles of haemopoietic cells is often adaptor protein complex 3-dependent (AP-3-dependent), and AP-3 has previously been shown to play a role in the trafficking of both WPB membrane proteins, P-selectin and CD63. However, WPB are thought to form at the trans Golgi network (TGN), which is inconsistent with a role for AP-3, which operates in post-Golgi trafficking. We have therefore investigated in detail the mechanisms of delivery of these two membrane proteins to WPB. We find that P-selectin is recruited to forming WPB in the trans-Golgi by AP-3-independent mechanisms that use sorting information within both the cytoplasmic tail and the lumenal domain of the receptor. In contrast, CD63 is recruited to already-budded WPB by an AP-3-dependent route. These different mechanisms of recruitment lead to the presence of distinct immature and mature populations of WPB in human umbilical vein endothelial cells (HUVEC).     

Induction of an interferon-gamma Stat3 response in nerve cells by pre-treatment with gp130 cytokines

Many cytokines mediate their effects through Jak/STAT signaling pathways providing many opportunities for cross-talk between different cytokines. We examined the interaction between two cytokine families, gp130-related cytokines and interferon-gamma (IFN-gamma), which are coexpressed in the nervous system during acute trauma and pathological conditions. Typical nerve cells show an IFN-gamma response that is restricted to activating STAT1, with minor activation of STAT3. IFN-gamma elicited a pronounced STAT3 response in cells pre-treated for 5-7 h with ciliary neurotrophic factor (CNTF), leukemia inhibitory factor or interleukin-6. CNTF or interleukin-6 induced an IFN-gamma STAT3 response in a variety of cells including SH-SY5Y human neuroblastoma, HMN-1 murine motor neuron hybrid cells, rat sympathetic neurons and human hepatoma HepG2 cells. The enhancement was measured as an increase in tyrosine phosphorylated STAT3, in STAT3-DNA binding and in STAT-luciferase reporter gene activity. The enhanced STAT3 response was not due to an increase in overall STAT3 levels but was dependent upon ongoing protein synthesis. The induction by CNTF was inhibited by the protein kinase C inhibitor, BIM, and the MAPK-kinase inhibitor, U0126. Further, H-35 hepatoma cells expressing gp130 receptor chimeras lacking either the SHP-2 docking site or the Box 3 STAT binding sites failed to enhance the IFN-gamma STAT3 response. These results provide evidence for an interaction between gp130 and IFN-gamma cytokines that can significantly alter the final cellular response to IFN-gamma.     

Organization and assembly of the TRAPPII complex

Current models suggest that TRAPP tethering complexes exist in two forms. Whereas the seven-subunit TRAPPI complex mediates ER-to-Golgi transport, TRAPPII contains three additional subunits (Trs65, Trs120 and Trs130) and is required for distinct tethering events at Golgi membranes. It is not clear how TRAPPII assembly is regulated. Here, we show that Tca17 is a fourth TRAPPII-specific component, and that Trs65 and Tca17 interact with distinct domains of Trs130 and make different contributions to complex assembly. Whereas Tca17 promotes the stable association of TRAPPII-specific subunits with the core complex, Trs65 stabilizes TRAPPII in an oligomeric form. We show that Trs85, which was previously reported to be a subunit of both TRAPPI and TRAPPII, is not associated with the TRAPPII complex in yeast. However, we find that proteins related to Trs85, Trs65 and Tca17 are part of the same TRAPP complex in mammalian cells. These findings have implications for models of TRAPP complex formation and suggest that TRAPP complexes may be organized differently in yeast and mammals.     

Screening of phytotoxicity of Alternaria macrospora MKP1 against Parthenium hysterophorus L.

Parthenium hysterophorus L. an exotic, pernicious weed is considered as one of the most troublesome weeds for agricultural sector by virtue of its high ecological amplitude and adaptability. Microbes and their by-products are now proved to be a worthy alternative to toxic chemicals used for weed management. Alternaria macrospora MKPI was isolated from the parthenium leaves infected with leaf blight and found pathogenic to the weed. The herbicidal potential of cell free culture filtrate of A. macrospora MKP1 has been tested against parthenium by employing detached leaf bioassay and seed germination bioassay and a significant damage was exhibited by the cultural filtrate of pathogen to the parthenium leaves and seeds.     

DDESC: Dragon database for exploration of sodium channels in human

Background

Hepcidin/LEAP-1 is an iron regulatory hormone originally identified as an antimicrobial peptide. As part of a systematic analysis of the evolution of host defense peptides in primates, we have sequenced the orthologous gene from 14 species of non-human primates.

Results

The sequence of the mature peptide is highly conserved amongst all the analyzed species, being identical to the human one in great apes and gibbons, with a single residue conservative variation in Old-World monkeys and with few substitutions in New-World monkeys.

Conclusion

Our analysis indicates that hepcidin's role as a regulatory hormone, which involves interaction with a conserved receptor (ferroportin), may result in conservation over most of its sequence, with the exception of the stretch between residues 15 and 18, which in New-World monkeys (as well as in other mammals) shows a significant variation, possibly indicating that this structural region is involved in other functions.     

Restoration of ultrastructural and biochemical changes in alloxan-induced diabetic rat sciatic nerve on treatment with Na3VO4 and Trigonella—a promising antidiabetic agent

Vanadium has been reported to have broad pharmacological activity both in vitro and in vivo. Vanadium compound, sodium orthovanadate, Na₃VO₄, is well known for its hypoglycaemic effects. However, Na₃VO₄ exerts these effects at relatively high doses (0.6 mg/ml) and exhibit several toxic effects. In the present study lower doses of Na₃VO₄ (0.2 mg/ml) are combined with Trigonella foenum graecum seed powder (TSP), another hypoglycaemic agent, to reduce its toxicity without compromising its antidiabetic potential. The efficacy of the lower doses of Na₃VO₄ has been investigated in restoring the altered glucose metabolism and histological structure in the sciatic nerves in 21 and 60 days alloxan diabetic rats. A portion of the glucose was found to be channelled from the normal glycolytic route to polyol pathway, evident by the reduced hexokinase activity and increased polyol pathway enzymes aldose reductase and sorbitol dehydrogenase activity causing accumulation of sorbitol and fructose in diabetic conditions. Ultrastructural observation of the sciatic nerve showed extensive demylination and axonal loss after eight weeks of diabetes induction. Blood glucose levels increased in diabetic rats were normalized with the lower dose of vanadium and Trigonella treatment. The treatment of the diabetic rats with vanadium and Trigonella prevented the activation of the polyol pathway and sugar accumulations. The sciatic nerves were also protected against the structural abnormalities found in diabetes with Trigonella foenum graecum as well as Na₃VO₄. Results suggest that lower doses of Na₃VO₄ may be used in combination with TSP as an efficient antidiabetic agent to effectively control the long-term complications of diabetes in tissues like peripheral nerve.     

Mutational study of the bacterial hemoglobin distal heme pocket

Ligand binding experiments on three mutants in the distal heme pocket of Vitreoscilla hemoglobin (GlnE7His, ProE8Ala, and GlnE7His,ProE8Ala) were used to probe the role of GlnE7 and ProE8 in the pocket's unusual structure. The oxygen dissociation constants for the wild type, E8Ala mutant, and E7His mutant proteins were 4.5, 4.7, and 1.7microM, respectively; the K(d) for the double mutant was not determinable by our technique. Visible-Soret spectra of the carbonyl and cyanyl forms and FT-IR of the carbonyl form of the E8 mutant were similar to those of the wild type; the opposite was true for the GlnE7His and GlnE7His,ProE8Ala mutants, which also differed from wild type in the visible-Soret spectra of their oxidized forms. Models of the effects of the mutations on distal pocket structure were consistent with the experimental findings, particularly the larger effects of the GlnE7His change.     

Impact of hypoglycemia and diabetes on CNS: correlation of mitochondrial oxidative stress with DNA damage

Oxidative stress plays an important role in tissue damage caused by hypoglycemia and diabetes, which may be the result of deterioration in glucose homeostasis caused by these metabolic disorders. The present study examined the effects of insulin-induced hypoglycemia and streptozotocin induced diabetes on mitochondrial lipid peroxidation and antioxidant enzymes from different brain regions, namely, cerebral hemispheres, cerebellum, brain stem and diencephalon. In situ localization of DNA single strand breaks (SSBs) were also studied by DNA polymerase-I mediated biotin dATP labeled nick translation method after inducing hypoglycemia and diabetes. Significant decrease in mitochondrial catalase, manganese superoxide-dismutase (Mn-SOD) and reduced glutathione (GSH) content and increase in the lipid peroxidation (LPx) and glutathione peroxidase (GPx) activity was observed under these metabolic stress conditions with more pronounced effects in hypoglycemic group. We conclude that during severe energy deprivation following hypoglycemia and diabetes, mitochondrial free radicals scavenger system is down regulated, which leads to reactive oxygen species (ROS) generation. High levels of ROS in turn activate the processes leading to DNA damage. DNA SSBs, which indicates nuclear disintegration is an important feature of neuronal cell death.     

The influence of zinc and sulphur deficiency on oil-filling in peanut (Arachis hypogaea L.) kernels

In the developing peanut (Arachis hypogaea L.) kernels, the period between 15 and 35 days after podding (DAP) was identified as the active period of oil-filling. The period of active oil-filling was associated with a decrease in the starch, soluble sugars and proteins so as to make available the energy and carbon skeleton for the synthesis of oil. The oil content in the mature kernels decreased by 11, 12 and 25 per cent with Zn, S and Zn+S deficiency, respectively. In addition, proteins and starch content decreased significantly while that of soluble sugars increased slightly. The activity of malate dehydrogenase and glucose-6-phosphate dehydrogenase also decreased due to Zn as well as S deficiency. The deficiency treatments resulted in a decrease in phospholipids, free fatty acids and triacylglycerols in mature kernels. Further the proportion of 16∶0 and 18∶2 decreased while that of 18∶1 increased in developing kernels.