174 research outputs found
Food Preferences of the Rubber Plantation Litter Beetle, Luprops tristis, a Nuisance Pest in Rubber Tree Plantations
Massive invasion of the litter dwelling beetle, Luprops tristis Fabricius (Coleoptera: Tenebrionidae), numbering about 0.5 to 4 million per residential building following summer showers, and their prolonged stay in a state of dormancy, make them an extreme nuisance in rubber tree plantation belts of the Western Ghats in south India. Food preference of post-dormancy adults, larvae and teneral adults stages towards tender, mature and senescent leaves were assessed in three choice and no choice leaf disc tests. All stages have strong preference towards fallen tender leaves and lowest preference towards senescent leaves indicating that leaf age is a major attribute determining food selection and food preference of L. tristis. Ready availability of the preferred, prematurely fallen, tender rubber tree leaves as a food resource is suggested as being responsible for the exceptionally high abundance of L. tristis in rubber tree plantation belts
Beta gamma-subunit activation of G-protein-regulated phospholipase C
The availability of purified G alpha 11 and the G-protein-regulated phospholipase C from turkey erythrocytes has allowed an examination of the direct effects of G-protein beta gamma-subunit on the components of the inositol lipid signaling system. Reconstitution of purified turkey erythrocyte or bovine brain beta gamma-subunit into phospholipid vesicles containing G alpha 11 inhibited AlF4- induced activation of phospholipase C. However, beta gamma-subunit at higher concentrations increased phospholipase C activity. This stimulatory effect of beta gamma-subunit on phospholipase C did not require the presence of the alpha-subunit. G alpha o had no effect on the catalytic activity of phospholipase C. However, coreconstitution of G alpha o and beta gamma-subunit shifted to the right the concentration-effect curve for beta gamma-subunit-promoted activation of phospholipase C. As was observed with G alpha 11, the increase in activity observed in the presence of beta gamma-subunit occurred as an increase in the maximal activity and with no change in the apparent affinity for Ca2+ for phospholipase C activation. The concentration dependence of G alpha 11 for activation of turkey erythrocyte phospholipase C and bovine brain phospholipase C-beta, as well as the concentration dependence of the two enzymes for activation by G alpha 11, were very similar. In contrast, beta gamma-subunit was a much less effective activator of bovine brain phospholipase C-beta than the turkey erythrocyte enzyme. The observation of direct effects of free beta gamma-subunit on phospholipase C extend the possibilities for receptor-mediated regulation of this signaling pathway
How and When Socially Entrepreneurial Nonprofit Organizations Benefit From Adopting Social Alliance Management Routines to Manage Social Alliances?
Social alliance is defined as the collaboration between for-profit and nonprofit organizations. Building on the insights derived from the resource-based theory, we develop a conceptual framework to explain how socially entrepreneurial nonprofit organizations (SENPOs) can improve their social alliance performance by adopting strategic alliance management routines. We test our framework using the data collected from 203 UK-based SENPOs in the context of cause-related marketing campaign-derived social alliances. Our results confirm a positive relationship between social alliance management routines and social alliance performance. We also find that relational mechanisms, such as mutual trust, relational embeddedness, and relational commitment, mediate the relationship between social alliance management routines and social alliance performance. Moreover, our findings suggest that different types of social alliance motivation can influence the impact of social alliance management routines on different types of the relational mechanisms. In general, we demonstrate that SENPOs can benefit from adopting social alliance management routines and, in addition, highlight how and when the social alliance management routines–social alliance performance relationship might be shaped. Our study offers important academic and managerial implications, and points out future research directions
Inhibition of Bacterial Conjugation by Phage M13 and Its Protein g3p: Quantitative Analysis and Model
Conjugation is the main mode of horizontal gene transfer that spreads antibiotic resistance among bacteria. Strategies for inhibiting conjugation may be useful for preserving the effectiveness of antibiotics and preventing the emergence of bacterial strains with multiple resistances. Filamentous bacteriophages were first observed to inhibit conjugation several decades ago. Here we investigate the mechanism of inhibition and find that the primary effect on conjugation is occlusion of the conjugative pilus by phage particles. This interaction is mediated primarily by phage coat protein g3p, and exogenous addition of the soluble fragment of g3p inhibited conjugation at low nanomolar concentrations. Our data are quantitatively consistent with a simple model in which association between the pili and phage particles or g3p prevents transmission of an F plasmid encoding tetracycline resistance. We also observe a decrease in the donor ability of infected cells, which is quantitatively consistent with a reduction in pili elaboration. Since many antibiotic-resistance factors confer susceptibility to phage infection through expression of conjugative pili (the receptor for filamentous phage), these results suggest that phage may be a source of soluble proteins that slow the spread of antibiotic resistance genes
T Cell-Intrinsic and -Extrinsic Contributions of the IFNAR/STAT1-Axis to Thymocyte Survival
STAT1 is an essential part of interferon signaling, and STAT1-deficiency results in heightened susceptibility to infections or autoimmunity in both mice and humans. Here we report that mice lacking the IFNα/β-receptor (IFNAR1) or STAT1 display impaired deletion of autoreactive CD4+CD8+-T-cells. Strikingly, co-existence of WT T cells restored thymic elimination of self-reactive STAT1-deficient CD4+CD8+-T cells. Analysis of STAT1-deficient thymocytes further revealed reduced Bim expression, which was restored in the presence of WT T cells. These results indicate that type I interferons and STAT1 play an important role in the survival of MHC class I-restricted T cells in a T cell intrinsic and non-cell intrinsic manner that involves regulation of Bim expression through feedback provided by mature STAT1-competent T cells
Complications of Peripherally Inserted Central Venous Catheters: A Retrospective Cohort Study
Background and Aim
The use of venous catheters is a widespread practice, especially in oncological and oncohematological units. The objective of this study was to evaluate the complications associated with peripherally inserted central catheters (PICCs) in a cohort of patients.
Materials and Methods
In this retrospective cohort study, we included all patient carrying PICCs (n = 603) inserted at our institute between October 2010 and December 2013. The main variables collected were medical diagnosis, catheter care, location, duration of catheterization, reasons for catheter removal, complications, and nursing care. Complications were classified as infection, thrombosis, phlebitis, migration, edema, and/or ecchymosis.
Results
All patients were treated according to the same “nursing care” protocol. The incidence rate of complications was two cases per 1000 days of catheter duration. The most relevant complications were infection and thrombosis, both with an incidence of 0.17 cases per 1000 days of the total catheterization period. The total average duration of catheterization was 170 days [SD 6.06]. Additionally to “end of treatment” (48.42%) and “exitus”, (22.53%) the most frequent cause of removal was migration (displacement towards the exterior) of the catheter (5.80%).
Conclusions
PICCs are safe devices that allow the administration of long-term treatment and preserve the integrity of the venous system of the patient. Proper care of the catheter is very important to improve the quality life of patients with oncologic and hematologic conditions. Therefore, correct training of professionals and patients as well as following the latest scientific recommendations are particularly relevant
A review of estimation of distribution algorithms in bioinformatics
Evolutionary search algorithms have become an essential asset in the algorithmic toolbox for solving high-dimensional optimization problems in across a broad range of bioinformatics problems. Genetic algorithms, the most well-known and representative evolutionary search technique, have been the subject of the major part of such applications. Estimation of distribution algorithms (EDAs) offer a novel evolutionary paradigm that constitutes a natural and attractive alternative to genetic algorithms. They make use of a probabilistic model, learnt from the promising solutions, to guide the search process. In this paper, we set out a basic taxonomy of EDA techniques, underlining the nature and complexity of the probabilistic model of each EDA variant. We review a set of innovative works that make use of EDA techniques to solve challenging bioinformatics problems, emphasizing the EDA paradigm's potential for further research in this domain
Bacterial Effector Binding to Ribosomal Protein S3 Subverts NF-κB Function
Enteric bacterial pathogens cause food borne disease, which constitutes an enormous economic and health burden. Enterohemorrhagic Escherichia coli (EHEC) causes a severe bloody diarrhea following transmission to humans through various means, including contaminated beef and vegetable products, water, or through contact with animals. EHEC also causes a potentially fatal kidney disease (hemolytic uremic syndrome) for which there is no effective treatment or prophylaxis. EHEC and other enteric pathogens (e.g., enteropathogenic E. coli (EPEC), Salmonella, Shigella, Yersinia) utilize a type III secretion system (T3SS) to inject virulence proteins (effectors) into host cells. While it is known that T3SS effectors subvert host cell function to promote diarrheal disease and bacterial transmission, in many cases, the mechanisms by which these effectors bind to host proteins and disrupt the normal function of intestinal epithelial cells have not been completely characterized. In this study, we present evidence that the E. coli O157:H7 nleH1 and nleH2 genes encode T3SS effectors that bind to the human ribosomal protein S3 (RPS3), a subunit of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) transcriptional complexes. NleH1 and NleH2 co-localized with RPS3 in the cytoplasm, but not in cell nuclei. The N-terminal region of both NleH1 and NleH2 was required for binding to the N-terminus of RPS3. NleH1 and NleH2 are autophosphorylated Ser/Thr protein kinases, but their binding to RPS3 is independent of kinase activity. NleH1, but not NleH2, reduced the nuclear abundance of RPS3 without altering the p50 or p65 NF-κB subunits or affecting the phosphorylation state or abundance of the inhibitory NF-κB chaperone IκBα NleH1 repressed the transcription of a RPS3/NF-κB-dependent reporter plasmid, but did not inhibit the transcription of RPS3-independent reporters. In contrast, NleH2 stimulated RPS3-dependent transcription, as well as an AP-1-dependent reporter. We identified a region of NleH1 (N40-K45) that is at least partially responsible for the inhibitory activity of NleH1 toward RPS3. Deleting nleH1 from E. coli O157:H7 produced a hypervirulent phenotype in a gnotobiotic piglet model of Shiga toxin-producing E. coli infection. We suggest that NleH may disrupt host innate immune responses by binding to a cofactor of host transcriptional complexes
TWIST1 Is Expressed in Colorectal Carcinomas and Predicts Patient Survival
TWIST1 is a transcription factor that belongs to the family of basic helix-loop-helix proteins involved in epithelial-to-mesenchymal transition and invasion processes. The TWIST1 protein possesses oncogenic, drug-resistant, angiogenic and invasive properties, and has been related with several human tumors and other pathologies. Colorectal cancer is one of the tumors in which TWIST1 is over-expressed, but its involvement in the clinical outcome of the disease is still unclear. We tested, by RT-PCR, the expression levels of TWIST1 in normal and tumor paired-sample tissues from a series of 151 colorectal cancer patients, in order to investigate its prognostic value as a tumor marker. TWIST1 expression was restricted to tumor tissues (86.1%) and correlated with lymph node metastasis (LNM). Adjusted analysis showed that the expression levels of TWIST1 correlated with overall survival (OS) and disease-free survival (DFS). Importantly, TWIST1 expression levels predicted OS specifically at stages I and II. Moreover, patients with stage II tumors and high TWIST1 levels showed even shorter survival than patients with stage III tumors. These results suggest that TWIST1 expression levels could be a tumor indicator in stage II patients and help select patients at greater risk of poor prognosis who might benefit from adjuvant chemotherapy
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