Mechanisms of Hemagglutinin Targeted Influenza Virus Neutralization

Human monoclonal antibodies have been identified which neutralize broad spectra of influenza A or B viruses. Here, we dissect the mechanisms by which such antibodies interfere with infectivity. We distinguish four mechanisms that link the conserved hemagglutinin (HA) epitopes of broadly neutralizing antibodies to critical processes in the viral life cycle. HA-stem binding antibodies can act intracellularly by blocking fusion between the viral and endosomal membranes and extracellularly by preventing the proteolytic activation of HA. HA-head binding antibodies prevent viral attachment and release. These insights into newly identified ways by which the human immune system can interfere with influenza virus infection may aid the development of novel universal vaccines and antivirals.     

Genome Sequence of the Aerobic Bacterium Bacillus sp. Strain FJAT-13831

Bacillus sp. strain FJAT-13831 was isolated from the no. 1 pit soil of Emperor Qin''s Terracotta Warriors in Xi''an City, People''s Republic of China. The isolate showed a close relationship to the Bacillus cereus group. The draft genome sequence of Bacillus sp. FJAT-13831 was 4,425,198 bp in size and consisted of 5,567 genes (protein-coding sequences [CDS]) with an average length of 782 bp and a G+C value of 36.36%.     

Influence of Reciprocal Links in Social Networks

How does reciprocal links affect the function of real social network? Does reciprocal link and non-reciprocal link play the same role? Previous researches haven''t displayed a clear picture to us until now according to the best of our knowledge. Motivated by this, in this paper, we empirically study the influence of reciprocal links in two representative real datasets, Sina Weibo and Douban. Our results demonstrate that the reciprocal links play a more important role than non-reciprocal ones in information diffusion process. In particular, not only coverage but also the speed of the information diffusion can be significantly enhanced by considering the reciprocal effect. We give some possible explanations from the perspectives of network connectivity and efficiency. This work may shed some light on the in-depth understanding and application of the reciprocal effect in directed online social networks.     

H2S catalysed by CBS regulates testosterone synthesis through affecting the sulfhydrylation of PDE

Testosterone deficiency resulted in increased mortality in men. Our previous work found that hydrogen sulphide (H₂S) significantly alleviated the spermatogenesis disorder. To investigate whether H₂S could regulate testosterone synthesis and the relative signalling pathways. Disorder model of testosterone synthesis was constructed in vitro and in vivo. The cell viability was detected using CCK-8 method. The concentration of H₂S and testosterone were examined using ELISA kits. The relative mRNA and protein expression of CBS, PDE4A, PDE8A and proteins related to testosterone synthesis were detected by RT-qPCR and western blotting. PAS staining was used to detect the inflammatory status of testis. The sulfhydryl level of PDE4A and PDE8A was determined by Biotin Switch Technique. CBS overexpression inhibited while knockdown promoted LPS + H₂O₂ induced injury in testosterone synthesis of MLTC-1 cells, though regulating the level of H₂S. The LPS + H₂O₂ induced inhibition on cAMP and p-PKA was recovered by CBS overexpression, while addition of the specific inhibitor of PKA had opposite effects. CBS overexpression alleviated the inflammation status in testis and promoted the expression of StAR, P450scc, P450c17 and 3β-HSD. CBS could also exhibit its protective role through promoting sulfhydrylation of PDE4A and PDE8A. H₂S catalysed by CBS could recover testosterone synthesis in vitro and in vivo through inhibiting PDE expression via sulfhydryl modification and activating cAMP/PKA pathway.     

Spatio-Temporal Patterns in Rhizosphere Oxygen Profiles in the Emergent Plant Species Acorus calamus

Rhizosphere oxygen profiles are the key to understanding the role of wetland plants in ecological remediation. Though in situ determination of the rhizosphere oxygen profiles has been performed occasionally at certain growing stages within days, comprehensive study on individual roots during weeks is still missing. Seedlings of Acorus calamus, a wetland monocot, were cultivated in silty sediment and the rhizosphere oxygen profiles were characterized at regular intervals, using micro-optodes to examine the same root at four positions along the root axis. The rhizosphere oxygen saturation culminated at 42.9% around the middle part of the root and was at its lowest level, 3.3%, at the basal part of the root near the aboveground portion. As the plant grew, the oxygen saturation at the four positions remained nearly constant until shoot height reached 15 cm. When shoot height reached 60 cm, oxygen saturation was greatest at the point halfway along the root, followed by the point three-quarters of the way down the root, the tip of the root, and the point one-quarter of the way down. Both the internal and rhizosphere oxygen saturation steadily increased, as did the thickness of stably oxidized microzones, which ranged from 20 µm in younger seedlings to a maximum of 320 µm in older seedlings. The spatial patterns of rhizosphere oxygen profiles in sediment contrast with those from previous studies on radial oxygen loss in A. calamus that used conventional approaches. Rhizosphere oxygen saturation peaked around the middle part of roots and the thickness of stably oxidized zones increased as the roots grew.     

The influence of different aphid prey species on the biology and life table parameters of Propylaea japonica

The influence of three aphid prey species – Aphis craccivora Koch, Megoura viciae Buckton and Rhopalosiphum maidis (Fitch) – on the biology of Propylaea japonica (Thunberg) was studied under laboratory conditions. The development, survivorship, longevity, reproduction and life table parameters of P. japonica differed significantly among different treatments. The shortest developmental period of P. japonica (from first-instar larvae to adult) was observed on A. craccivora, whereas the longest was observed on M. viciae. The highest survivorship was observed on A. craccivora, and the lowest survivorship was observed on M. viciae. The highest sex ratio, fecundity and the shortest pre-oviposition period were observed when A. craccivora was used as prey. The longevities of P. japonica females and males did not differ significantly when reared on different aphid species. The highest values of net reproductive rate, intrinsic rate of increase and finite rate of increase were observed on A. craccivora. The results suggest that A. craccivora is a suitable prey for P. japonica among the three aphid species tested and can serve as a diet for the mass rearing of P. japonica under laboratory conditions for possible use in integrated pest management.     

Novel NGF-potentiating diterpenoids from a Brazilian medicinal plant,Ptychopetalum olacoides

From the MeOH extract of Ptychopetalum olacoides, which is used in Brazilian folk medicine for the treatment of chronic degenerative conditions of the nervous system, four novel clerodane-type diterpenoids named 6α,7α-dihydroxyannonene (1), 7α,20-dihydroxyannonene (2), 7α-hydroxysolidagolactone I (3), and ptycho-6α,7α-diol (4) were isolated by bioassay-directed fractionation using NGF-differentiated PC12 cells. The structures of 1–4 were established by extensive NMR spectroscopic analyses and chemical conversion. Compounds 1 and 2 significantly enhanced NGF-mediated neurite outgrowth in PC12 cells at concentrations ranging from 0.1 to 50.0 μM for 1 and 0.1 to 30.0 μM for 2, whereas 3 and 4 had no morphological effect on NGF-mediated PC12 cells in the same concentration range. The structure–activity relationship of these compounds is also discussed.     

Is unconventional secretion inhibited during cell division by Cdk1 activity?

A process of unconventional secretion that is dependent on the Golgi stacking protein GRASP and multiple components of the autophagy machinery has recently been documented for several cytoplasmic and membrane protein. Classical secretion via the exocytic pathway is inhibited during cell division in animal cells, as key membrane compartments, particularly the Golgi, are disassembled and fragmented. The question as to whether unconventional secretion is likewise inhibited during mitosis has not been explored. This mode of secretion supposedly bypasses the Golgi. However, GRASP and Vps34 (a key autophagy protein) are both substrates of the cell cycle regulating cyclin‐dependent kinase 1 (Cdk1), and their activities are apparently inhibited by Cdk1 phosphorylation. Is unconventional secretion therefore similarly inhibited during cell division like conventional secretion? The story may yet turn out to be more complicated. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.