GIT1 activates p21-activated kinase through a mechanism independent of p21 binding

p21-activated kinases (PAKs) associate with a guanine nucleotide exchange factor, Pak-interacting exchange factor (PIX), which in turn binds the paxillin-associated adaptor GIT1 that targets the complex to focal adhesions. Here, a detailed structure-function analysis of GIT1 reveals how this multidomain adaptor also participates in activation of PAK. Kinase activation does not occur via Cdc42 or Rac1 GTPase binding to PAK. The ability of GIT1 to stimulate alphaPAK autophosphorylation requires the participation of the GIT N-terminal Arf-GAP domain but not Arf-GAP activity and involves phosphorylation of PAK at residues common to Cdc42-mediated activation. Thus, the activation of PAK at adhesion complexes involves a complex interplay between the kinase, Rho GTPases and protein partners that provide localization cues.     

PathoGene: a pathogen coding sequence discovery and analysis resource

PathoGene is a web-based resource that streamlines the process of predicting genes in microorganisms and designs PCR primers for amplification to facilitate sequence analysis and experimentation. PathoGene currently supports primer design for every complete microbial, viral, and fungal genome as cataloged in GenBank by the National Center for Biotechnology Information (NCBI; http://www.ncbi.nlm.nih.gov/). The resulting primers can then be subjected to a stand-alone Basic Local Alignment Search Tool (BLAST) system called PathoBLAST in which the predicted PCR product and/or primers can be compared against the genome of interest or a similar genome to find related genes or estimate primer quality.     

FlaC, a protein of Campylobacter jejuni TGH9011 (ATCC43431) secreted through the flagellar apparatus, binds epithelial cells and influences cell invasion

Type III secretion systems identified in bacterial pathogens of animals and plants transpose effectors and toxins directly into the cytosol of host cells or into the extracellular milieu. Proteins of the type III secretion apparatus are conserved among diverse and distantly related bacteria. Many type III apparatus proteins have homologues in the flagellar export apparatus, supporting the notion that type III secretion systems evolved from the flagellar export apparatus. No type III secretion apparatus genes have been found in the complete genomic sequence of Campylobacter jejuni NCTC11168. In this study, we report the characterization of a protein designated FlaC of C. jejuni TGH9011. FlaC is homologous to the N- and C-terminus of the C. jejuni flagellin proteins, FlaA and FlaB, but lacks the central portion of these proteins. flaC null mutants form a morphologically normal flagellum and are highly motile. In wild-type C. jejuni cultures, FlaC is found predominantly in the extracellular milieu as a secreted protein. Null mutants of the flagellar basal rod gene (flgF) and hook gene (flgE) do not secrete FlaC, suggesting that a functional flagellar export apparatus is required for FlaC secretion. During C. jejuni infection in vitro, secreted FlaC and purified recombinant FlaC bind to HEp-2 cells. Invasion of HEp-2 cells by flaC null mutants was reduced to a level of 14% compared with wild type, suggesting that FlaC plays an important role in cell invasion.     

Development and production of cholesterol-lowering <Emphasis Type="Italic">Monascus</Emphasis>-nata complex

This study develops a new foodstuff, the Monascus-nata complex, which combines the functions of cholesterol-lowering monacolin k and bacterial dietary-fibre. Two Monascus strains, M. ruber and M. pilosus were fermented within cubical bacterial cellulose, nata de coco, obtained from Acetobacter fermented coconut juice, in a conditioned medium. The production levels and stability of monacolin k in the cultured Monascus-nata complex were determined to develop optimal fermentation conditions. The results indicated that a medium that comprised 5% glucose and 1.5% ammonium phosphate at pH 6.0–7.0 produced the most monacolin k (157 mg/l) for Monascus pilosus NCHU M-35. However, monosodium glutamate (MSG) and 0.001% ZnSO₄ inhibited the intracellular accumulation of monacolin k. Monacolin k within the Monascus-nata complex was relatively resistant to washing and changes of pH, but thermal processing and freezing storage markedly reduced the amount present. This novel Monascus-nata complex is potentially a healthy foodstuff.     

Sequence Analysis of DNA Fragments from the Genome of the Primary Endosymbiont of the Whitefly <Emphasis Type="Italic">Bemisia tabaci</Emphasis>

The whitefly Bemisia tabaci contains a primary prokaryotic endosymbiont housed within specialized cells in the body cavity. Two DNA fragments from the endosymbiont, totaling 33.3 kilobases, were cloned and sequenced. In total, 37 genes were detected and included the ribosomal RNA operon and genes for ribosomal RNA proteins. The guanine plus cytosine of the DNA was 30.2 mol%, different from that of endosymbionts of other plant sap-sucking insects.     

Acute thoracic aortic dissection presenting as sore throat: report of a case

Acute dissection of the aorta can be one of the most dramatic of cardiovascular emergencies. Its symptoms can occur abruptly and progress rapidly. Prompt recognition and appropriate intervention is crucial. However, not all aortic dissections present with classic symptoms of abrupt chest, back, or abdominal pain, and the diagnosis may be missed. Aortic dissection presenting as a sore throat is quite unusual. A 53-year-old man presented with sore throat as the early symptom of an acute thoracic aortic dissection. Unfortunately, the diagnosis was delayed, and the patient died. Given the high morbidity and mortality after delayed recognition or misdiagnosis, aortic dissection should be considered in the differential diagnosis of a patient presenting with sore throat and normal findings of neck and throat, even when there is no classic symptoms.     

Improvement of recoveries for the determination of protozoa Cryptosporidium and Giardia in water using method 1623

The U.S. Environmental Protection Agency has developed method 1623 for simultaneous detection of Cryptosporidium oocysts and Giardia cysts in water. Method 1623 includes four major steps: filtration, immunomagnetic separation (IMS), fluorescent antibody (FA) staining and microscopic examination. It was noted that the recovery levels following IMS-FA and FA staining were high, averaging more than 92.0% and 89.0% for C. parvum oocysts and G. lamblia cysts, respectively. In contrast, when the filtration step was incorporated, the recovery level of C. parvum oocysts declined significantly to 18.1% in seeded tap water, while a relatively high recovery level of 77.2% for G. lamblia cysts could still be achieved. Further study indicated that the recovery level of C. parvum oocysts could be enhanced significantly when an appropriate amount of silica particles was added to a water sample. The recovery level of C. parvum oocysts was affected by particle size and concentration. The optimal silica particle size was determined to be within the range of 5-40 microm, and the corresponding optimal silica concentration was 1.42 g for 10-l tap water. When both G. lamblia cysts and C. parvum oocysts were spiked into the tap water sample containing the optimum amount of silica particles, the average recovery levels of oocysts and cysts were 82.7% and 75.4%, respectively. The results obtained clearly suggested that addition of an appropriate amount of silica particles could improve the recovery level of C. parvum oocysts significantly and yet there was no noticeable deleterious effect on the recovery level of G. lamblia cysts. Further study indicated that the rotation time in the IMS procedure using the Dynal GC-Combo IMS kit (which was recommended in method 1623) was important for G. lamblia cyst detection. In contrast, the recovery level of C. parvum oocysts was not affected by the rotation time. Furthermore, it was found that the recovery levels of C. parvum oocysts using methods 1622 and 1623 were quite close although different IMS kits were used in the two methods.     

Adustin, a small translation-inhibiting polypeptide from fruiting bodies of the wild mushroom Polyporus adusta

A polypeptide, with a molecular mass of 16.5 kDa as determined by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, has been isolated from the mushroom Polyporus adusta. The polypeptide, designated as adustin, inhibited translation in a cell-free rabbit reticulocyte lysate system with an IC50 of 0.34 microM. It was isolated using a protocol that involved ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on CM-Sepharose and fast protein liquid chromatography-gel filtration on Superdex 75. Adustin was unadsorbed on DEAE-cellulose, and adsorbed on Affi-gel blue gel and CM-Sepharose.