锈褐原花蝽在不同温度下的发育与积温必需条件

阿月浑子树木虱Agonoscena pistaciae Burckhardt and Lauterer （半翅目: 木虱总科）是伊朗园林树木阿月浑子树上常见的最具破坏性的害虫,其捕食性天敌锈褐原花蝽Anthocoris minki pistaciae Wagner在伊朗阿月浑子树种植区为该害虫的生防因子。本研究在17.5~35℃的8个恒温以及相对湿度55%±5%,光照周期16L∶8D的控制条件下,在A. pistaciae若虫上饲养这种捕食性花蝽的同时,调查温度对其发育的影响。结果表明：这种捕食性花蝽在17.5~32℃下可成功发育;然而在35℃下,卵不能孵化,且只有10%的若虫进入成虫阶段。30℃下从卵至成虫羽化的发育历期最短。据测算估计,这种捕食性花蝽的卵、若虫发育以及整个发育（卵至成虫）的积温分别为77,200和263度·日;卵、若虫和整个发育的低温度阈值分别为8.53, 9.2 和9.47℃。这些结果为建立阿月浑子树木虱的综合防治计划提供了宝贵的信息。     

TACO: Taxonomic prediction of unknown OTUs through OTU co-abundance networks

Background: A main goal of metagenomics is taxonomic characterization of microbial communities. Although sequence comparison has been the main method for the taxonomic classification, there is not a clear agreement on similarity calculation and similarity thresholds, especially at higher taxonomic levels such as phylum and class. Thus taxonomic classification of novel metagenomic sequences without close homologs in the biological databases poses a challenge. Methods: In this study, we propose to use the co-abundant associations between taxa/operational taxonomic units (OTU) across complex and diverse communities to assist taxonomic classification. We developed a Markov Random Field model to predict taxa of unknown microorganisms using co-abundant associations. Results: Although such associations are intrinsically functional associations, we demonstrate that they are strongly correlated with taxonomic associations and can be combined with sequence comparison methods to predict taxonomic origins of unknown microorganisms at phylum and class levels. Conclusions: With the ever-increasing accumulation of sequence data from microbial communities, we now take the first step to explore these associations for taxonomic identification beyond sequence similarity. Availability and Implementation: Source codes of TACO are freely available at the following URL: https://github.com/baharvand/OTU-Taxonomy-Identification implemented in C++, supported on Linux and MS Windows.     

Delayed combinatorial treatment with flavopiridol and minocycline provides longer term protection for neuronal soma but not dendrites following global ischemia

We previously reported that delayed administration of the general cyclin-dependent kinase inhibitor flavopiridol following global ischemia provided transient neuroprotection and improved behavioral performance. However, it failed to provide longer term protection. In the present study, we investigate the ability of delayed flavopiridol in combination with delayed minocycline, another neuroprotectant to provide sustained protection following global ischemia. We report that a delayed combinatorial treatment of flavopiridol and minocycline provides synergistic protection both 2 and 10 weeks following ischemia. However, protected neurons in the hippocampal CA1 are synaptically impaired as assessed by electrophysio logical field potential recordings. This is likely because of the presence of degenerated processes in the CA1 even with combinatorial therapy. This indicates that while we have addressed one important pre-clinical parameter by dramatically improving long-term neuronal survival with delayed combinatorial therapy, the issue of synaptic preservation of protected neurons still exists. These results also highlight the important observation that protection does not always lead to proper function.     

Overexpression,one-step purification,and characterization of a type II cholesterol oxidase from a local isolate <Emphasis Type="Italic">Rhodococcus</Emphasis> sp. PTCC 1633

A 1.6 kb gene encoding a cholesterol oxidase (choR) from a local isolate, Rhodococcus sp. PTCC 1633 was cloned into pET23a and the highly expressed recombinant enzyme was purified from the cell lysate of IPTG-induced Escherichia coli BL21(DE3)pLysS with one-step absorption on cholesterol. The purified protein had a molecular mass of 55 kDa, isoelectric point at about pH 9.0 and absorption peaks at 280, 380 and 460 nm, indicating that the enzyme is a flavoprotein. The optimum pH and temperature for the recombinant enzyme were 7.0 and 50°C, respectively. Steady-state kinetic revealed that the cholesterol oxidase had a K _m of 32 μM. This study is the first report concerning expression and one-step purification of a gene encoding cholesterol oxidase from Rhodococcus spp. This study revealed that this enzyme is a type II cholesterol oxidase.     

Endophytic fungus Piriformospora indica induced systemic resistance against rice sheath blight via affecting hydrogen peroxide and antioxidants

In this study, the effect of endophytic fungus Piriformospora indica on Rhizoctonia solani AG1-IA, causal agent of sheath blight disease, was investigated. In addition, plant defence responses activated in P. indica-inoculated rice plants were analysed. Two-week-old seedlings were inoculated by dipping their roots in P. indica chlamydospore suspension and transferred to pots containing sterilized soil. After two weeks, the seedlings pre-inoculated with P. indica were inoculated with R. solani. Statistical analysis of biological indicators showed that application of P. indica increased both fresh and dry weight of rice shoots and roots, compared to those of uninoculated healthy controls and the samples only inoculated with R. solani. Accumulation of hydrogen peroxide (H₂O₂) and activity of antioxidants such as superoxide dismutase (SOD) and guaiacol peroxidase (GPX) in plants inoculated with P. indica, R. solani, and P. indica-R. solani were investigated. The obtained results revealed that P. indica not only increased the plant biomass, but also delayed the infection process of R. solani and decreased sheath blight severity. Decreased severity of the disease was associated with decreased levels of H₂O₂ and increased SOD activity. Considering the necessity of reducing fungicide application, using P. indica in seedling bed before transplantation to the field could be a novel and effective method to increase rice production and decrease sheath blight progress.     

CD19 signaling pathways play a major role for murine AIDS induction and progression

Infection of genetically susceptible mice with the LP-BM5 mixture of murine leukemia viruses including an etiologic defective virus (BM5def) causes an immunodeficiency syndrome called murine AIDS (MAIDS). The disease is characterized by interactions between B cells and CD4(+) T cells resulting in polyclonal activation of both cell types. It is known that BM5def is expressed at highest levels in B cells and that B cells serve as viral APC. The CD19-CD21 complex and CD22 on the surface of B cells play critical roles as regulators of B cell responses to a variety of stimuli, influencing cell activation, differentiation, and survival. CD19 integrates positive signals induced by B cell receptor ligation by interacting with the protooncogene Vav, which leads to subsequent tyrosine phosphorylation of this molecule. In contrast, CD22 negatively regulates Vav phosphorylation. To analyze the role of CD19, CD21, Vav, and CD22 in MAIDS, we infected mice deficient in CD19, CD21 (CR2), Vav-1, or CD22 with LP-BM5 murine leukemia viruses. Infected CR2(-/-) mice developed MAIDS with a time course and severity indistinguishable from that of wild-type mice. In contrast, CD19 as well as Vav-1 deficiency restricted viral replication and suppressed the development of typical signs of MAIDS including splenomegaly, lymphadenopathy, and hypergammaglobulinemia. Finally, CD22 deficiency was found to accelerate MAIDS development. These results provide novel insights into the B cell signaling pathways required for normal induction and progression of MAIDS.     

Large Plasmonic Resonance Shifts from Metal Loss in Slits

Plasmonics - The impact of loss on the plasmonic resonances in metal–insulator–metal slits is analyzed, particularly the significant effect of loss on the reflection phase. The...     

Syndecan-4-dependent Rac1 regulation determines directional migration in response to the extracellular matrix

Cell migration in wound healing and disease is critically dependent on integration with the extracellular matrix, but the receptors that couple matrix topography to migratory behavior remain obscure. Using nano-engineered fibronectin surfaces and cell-derived matrices, we identify syndecan-4 as a key signaling receptor determining directional migration. In wild-type fibroblasts, syndecan-4 mediates the matrix-induced protein kinase Calpha (PKCalpha)-dependent activation of Rac1 and localizes Rac1 activity and membrane protrusion to the leading edge of the cell, resulting in persistent migration. In contrast, syndecan-4-null fibroblasts migrate randomly as a result of high delocalized Rac1 activity, whereas cells expressing a syndecan-4 cytodomain mutant deficient in PKCalpha regulation fail to localize active Rac1 to points of matrix engagement and consequently fail to recognize and respond to topographical changes in the matrix.     

Rn7SK small nuclear RNA is involved in cellular senescence

Rn7SK is a conserved small nuclear noncoding RNA which its function in aging has not been studied. Recently, we have demonstrated that Rn7SK overexpression reduces cell viability and is significantly downregulated in stem cells, human tumor tissues, and cell lines. In this study, we analyzed the role of Rn7SK on senescence in adipose tissue-derived mesenchymal stem cells (AD-MSCs). For this purpose, Rn7SK expression was downregulated and upregulated via transfection and transduction, respectively, in AD-MSCs and subsequently, various distinct characteristics of senescence including cell viability, proliferation, colony formation, senescence-associated β galactosidase activity, and differentiation potency was analyzed. Our results demonstrated the transient knockdown of Rn7SK in MSCs leads to delayed senescence, while its overexpressions shows opposite effects. When osteogenic differentiation was started, however, they exhibited a greater differentiation potential than the original MSCs, suggesting a potential tool for stem cell-based regenerative medicine.