Efficient adventitious shoot regeneration and somatic embryogenesis in pea

A rapid and simple method for adventitious shoot regeneration and somatic embryogenesis from immature cotyledon explants of pea (Pisum sativum L.) is described. Cotyledon size and the explant orientation to the medium surface were shown to have a clear effect on shoot regeneration. The highest frequency of shoot regeneration was achieved when the distal end of the greenest cotyledons (7–8 mm in size) were placed in contact with the agar surface. Shoots rooted at a frequency of 80–90% and grew into normal fertile plants. Somatic embryos were induced in cultures of immature cotyledons on modified MS medium containing high levels of -naphthaleneacetic acid (27–215 M) and 2,4-dichlorophenoxyacetic acid (23–181 M). A higher frequency of somatic embryos with a normal morphology were induced using -naphthaleneacetic acid.Abbreviations BA 6-benzyladenine - 2,4-d dichlorophenoxyacetic acid - IBA indole-3-butyric acid - NAA -naphthaleneacetic acid     

HCV core protein immunization with Montanide/CpG elicits strong Th1/Th2 and long-lived CTL responses

An efficient vaccine against Hepatitis C virus (HCV) infection requires induction of strong humoral and cellular responses against viral proteins. We evaluated the immunogenicity of HCV core protein (HCVcp), a prime vaccine candidate, formulated in various human compatible adjuvants. An Escherichia coli-expressed HCVcp, purified in native conditions was used for murine immunization in separate groups of: free HCVcp (Ag), Ag+C/IFA (Freunds), Ag+CpG, Ag+M720 (Montanide ISA 720), Ag+F127 (Pluronic acid) and cocktails of Ag+F127+CpG and Ag+M720+CpG. Mice immunized with M720(+CpG) developed the highest HCVcp-specific titers of total IgG, IgG1, 2a, 2b, and that of IFN-gamma and IL-4 cytokines compared to all other groups. HCVcp-specific-CTLs against relevant MHC class I peptides were detected only for Ag+M720+CpG, Ag+M720, and Ag+CpG groups and could be blocked by antimouse-CD8 antibodies. While CTLs were stable, only F127 formulated groups demonstrated detectable IgG antibodies one year post-immunization. Hence, HCVcp formulated in M720 (with a synergistic effect by inclusion of CpG) could induce balanced and strong Th1/Th2 responses with long-lived CD4(-)CD8(+) CTLs.     

Critical involvement of the ATM-dependent DNA damage response in the apoptotic demise of HIV-1-elicited syncytia

DNA damage can activate the oncosuppressor protein ataxia telangiectasia mutated (ATM), which phosphorylates the histone H2AX within characteristic DNA damage foci. Here, we show that ATM undergoes an activating phosphorylation in syncytia elicited by the envelope glycoprotein complex (Env) of human immunodeficiency virus-1 (HIV-1) in vitro. This was accompanied by aggregation of ATM in discrete nuclear foci that also contained phospho-histone H2AX. DNA damage foci containing phosphorylated ATM and H2AX were detectable in syncytia present in the brain or lymph nodes from patients with HIV-1 infection, as well as in a fraction of blood leukocytes, correlating with viral status. Knockdown of ATM or of its obligate activating factor NBS1 (Nijmegen breakage syndrome 1 protein), as well as pharmacological inhibition of ATM with KU-55933, inhibited H2AX phosphorylation and prevented Env-elicited syncytia from undergoing apoptosis. ATM was found indispensable for the activation of MAP kinase p38, which catalyzes the activating phosphorylation of p53 on serine 46, thereby causing p53 dependent apoptosis. Both wild type HIV-1 and an HIV-1 mutant lacking integrase activity induced syncytial apoptosis, which could be suppressed by inhibiting ATM. HIV-1-infected T lymphoblasts from patients with inactivating ATM or NBS1 mutations also exhibited reduced syncytial apoptosis. Altogether these results indicate that apoptosis induced by a fusogenic HIV-1 Env follows a pro-apoptotic pathway involving the sequential activation of ATM, p38MAPK and p53.     

Childhood Hygienic Practice and Family Education Status Determine the Prevalence of Helicobacter pylori Infection in Iran

Background: Management of Helicobacter pylori , a causative agent of gastrointestinal diseases is an important health problem in most countries. The main reasons include poorly defined epidemiological status and unrecognized mode of bacterial transmission. Our objective was to investigate the prevalence of H. pylori infection in a representative population of Iran and to evaluate possible risk factors for the H. pylori infection.
Materials and methods: In this cross-sectional study, 2561 healthy individuals aged 18–65 years (mean age, 35.5 years) were selected out of 12,100,000 inhabitants of Tehran province by cluster sampling. Infection with H. pylori was evaluated by detection of anti- H. pylori IgG antibody in serum. Sociodemographic status of each subject was determined by filling up a questionnaire.
Results: Prevalence of H. pylori infection was 69% and was correlated with increasing age. The highest infection rate (79.2%) was seen in individuals 46–55 years old. No association was detected between H. pylori positivity and gender. Low education of the study subjects; low father's and mother's education; poor tooth brushing habit; crowded families in childhood; and lack of household bath, hygienic drinking water, and swage disposal facility in childhood were determined as possible risk factors.
Conclusions: The rate of prevalence of H. pylori infection was higher than developed countries. Low socioeconomic status, poor sanitary indications, and crowded families in childhood were related to high prevalence of H. pylori infection in Iran. Accordingly, fecal–oral and oral–oral routes could be considered as the main pathways of transmission of H. pylori .     

Examination of the protective roles of helmet/faceshield and directionality for human head under blast waves

A parametric study was conducted to delineate the efficacy of personal protective equipment (PPE), such as ballistic faceshields and advanced combat helmets, in the case of a blast. The propagations of blast waves and their interactions with an unprotected head, a helmeted one, and a fully protected finite element head model (FEHM) were modeled. The biomechanical parameters of the brain were recorded when the FEHM was exposed to shockwaves from the front, back, top, and bottom. The directional dependent tissue response of the brain and the variable efficiency of PPE with respect to the blast orientation were two major results of this study.     

MicroRNA and target protein patterns reveal physiopathological features of glioma subtypes

Gliomas such as oligodendrogliomas (ODG) and glioblastomas (GBM) are brain tumours with different clinical outcomes. Histology-based classification of these tumour types is often difficult. Therefore the first aim of this study was to gain microRNA data that can be used as reliable signatures of oligodendrogliomas and glioblastomas. We investigated the levels of 282 microRNAs using membrane-array hybridisation and real-time PCR in ODG, GBM and control brain tissues. In comparison to these control tissues, 26 deregulated microRNAs were identified in tumours and the tissue levels of seven microRNAs (miR-21, miR-128, miR-132, miR-134, miR-155, miR-210 and miR-409-5p) appropriately discriminated oligodendrogliomas from glioblastomas. Genomic, epigenomic and host gene expression studies were conducted to investigate the mechanisms involved in these deregulations. Another aim of this study was to better understand glioma physiopathology looking for targets of deregulated microRNAs. We discovered that some targets of these microRNAs such as STAT3, PTBP1 or SIRT1 are differentially expressed in gliomas consistent with deregulation of microRNA expression. Moreover, MDH1, the target of several deregulated microRNAs, is repressed in glioblastomas, making an intramitochondrial-NAD reduction mediated by the mitochondrial aspartate-malate shuttle unlikely. Understanding the connections between microRNAs and bioenergetic pathways in gliomas may lead to identification of novel therapeutic targets.     

Protective Action of Spermine and Spermidine against Photoinhibition of Photosystem I in Isolated Thylakoid Membranes

The photo-stability of photosystem I (PSI) is of high importance for the photosynthetic processes. For this reason, we studied the protective action of two biogenic polyamines (PAs) spermine (Spm) and spermidine (Spd) on PSI activity in isolated thylakoid membranes subjected to photoinhibition. Our results show that pre-loading thylakoid membranes with Spm and Spd reduced considerably the inhibition of O₂ uptake rates, P700 photooxidation and the accumulation of superoxide anions (O₂ ⁻) induced by light stress. Spm seems to be more effective than Spd in preserving PSI photo-stability. The correlation of the extent of PSI protection, photosystem II (PSII) inhibition and O₂ ⁻ generation with increasing Spm doses revealed that PSI photo-protection is assumed by two mechanisms depending on the PAs concentration. Given their antioxidant character, PAs scavenge directly the O₂ ⁻ generated in thylakoid membranes at physiological concentration (1 mM). However, for non-physiological concentration, the ability of PAs to protect PSI is due to their inhibitory effect on PSII electron transfer.     

Human kallikrein 6 inhibitors with a para-amidobenzylanmine P1 group identified through virtual screening

A series of hK6 inhibitors with a para-amidobenzylamine P1 group and a 2-hydroxybenzamide scaffold linker was discovered through virtual screening. The X-ray structure of hK6 complexed with compound 9b was determined to a resolution of 1.68 Å. The tertiary folding of the hK6 complexed with the inhibitor is conserved relative to the structure of the apo-protein, whereas the interaction between hK6 and the inhibitor is consistent with both the SAR and the in silico model used in the virtual screening.     

Structural studies of SNARE complex and its interaction with complexin by molecular dynamics simulation

Since neurotransmitter releasing into the synaptic space delivers electrical signals from presynaptic neural cell to the postsynaptic cell, neurotransmitter secretion must be much orchestrated. Crowded intracellular vesicles involving neurotransmitters present a question of the how secretory vesicles fuse onto the plasma membrane in a fast synchronized fashion. Complexin is one of the most experimentally studied proteins that regulate assembly of fusogenic four‐helix SNARE complex to synchronized neurotransmitter secretion. We used MD simulation to investigate the interaction of complexin with the neural SNARE complex in detail. Our results show that the SNARE complex interacts with the complexin central helix by forming salt bridges and hydrogen bonds. Complexin also can interact with the Q‐SNARE complex instead of synaptobrevin to decrease the Q‐SNARE flexibility. The complexin alpha‐accessory helix and the C‐terminal region of synaptobrevin can interact with the same region of syntaxin. Although the alpha‐accessory helix aids the tight binding of the central helix to the SNARE complex, its proximity with synaptobrevin causes the destabilization of syntaxin and Sn1 helices. This study suggests that the alpha‐accessory helix of complexin can be an inhibiting factor for membrane fusion by competing with synaptobrevin for binding to the Q‐SNARE complex. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 560–570, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com