Rapid Identification of Legionella Pathogenicity by Surface-Enhanced Raman Spectroscopy.

OBJECTIVE: To establish Surface-enhanced Raman Spectroscopy (SERS) can be used as a rapid and reliable method to distinguish virulent strain and mild strain of L. pneumophila. METHODS: Mortality data were collected from company departments through administrative documents, death certificates, etc. Trend analyses of cancer mortality were performed on the basis of 925 cancer deaths between 2001 and 2010. RESULTS: Our results indicated that the peaks of high virulence strains reached ⋝4000. This criterion was verified by subsequent cell experiments. In addition, we also conducted SERS rapid identification on the virulence of several collected clinical strains and obtained accurate results. CONCLUSION: The present study indicates that the established SERS protocol can be used as a rapid and reliable method to distinguish virulent and mildly virulent strains of L. pneumophila, which can be further used in clinical samples.

The periplasmic PDZ domain-containing protein Prc modulates full virulence, envelops stress responses, and directly interacts with dipeptidyl peptidase of Xanthomonas oryzae pv. oryzae.

PDZ domain-containing proteases, also known as HtrA family proteases, play important roles in bacterial cells by modulating disease pathogenesis and cell-envelope stress responses. These proteases have diverse functions through proteolysis- and nonproteolysis-dependent modes. Here, we report that the genome of the causative agent of rice bacterial blight, Xanthomonas oryzae pv. oryzae, encodes seven PDZ domain-containing proteins. Systematic inactivation of their encoding genes revealed that PXO_01122 and PXO_04290 (prc) are involved in virulence. prc encodes a putative HtrA family protease that localizes in the bacterial periplasm. Mutation of prc also resulted in susceptibility to multiple environmental stresses, including H2O2, sodium dodecylsulfate, and osmolarity stresses. Comparative subproteomic analyses showed that the amounts of 34 periplasmic proteins were lower in the prc mutant than in wild-type. These proteins were associated with proteolysis, biosynthesis of macromolecules, carbohydrate or energy metabolism, signal transduction, and protein translocation or folding. We provide in vivo and in vitro evidence demonstrating that Prc stabilizes and directly binds to one of these proteins, DppP, a dipeptidyl peptidase contributing to full virulence. Taken together, our results suggest that Prc contributes to bacterial virulence by acting as a periplasmic modulator of cell-envelope stress responses.

Enhancing electro-transformation competency of recalcitrant Bacillus amyloliquefaciens by combining cell-wall weakening and cell-membrane fluidity disturbing.

Bacillus amyloliquefaciens has been a major workhorse for the production of a variety of commercially important enzymes and metabolites for the past decades. Some subspecies of this bacterium are recalcitrant to exogenous DNA, and transformation with plasmid DNA is usually less efficient, thereby limiting the genetic manipulation of the recalcitrant species. In this work, a methodology based on electro-transformation has been developed, in which the cells were grown in a semicomplex hypertonic medium, cell walls were weakened by adding glycine (Gly) and DL-threonine (DL-Thr), and the cell-membrane fluidity was elevated by supplementing Tween 80. After optimization of the cell-loosening recipe by response surface methodology (RSM), the transformation efficiency reached 1.13 ± 0.34 × 10(7) cfu/µg syngeneic pUB110 DNA in a low conductivity electroporation buffer. Moreover, by temporary heat inactivation of the host restriction enzyme, a transformation efficiency of 8.94 ± 0.77 × 10(5) cfu/µg DNA was achieved with xenogeneic shuttle plasmids, a 10(3)-fold increase compared to that reported previously. The optimized protocol was also applicable to other recalcitrant B. amyloliquefaciens strains used in this study. This work could shed light on the functional genomics and subsequent strain improvement of the recalcitrant Bacillus, which are difficult to be transformed using conventional methods.

[Clinical characteristic analysis of the first human case infected by influenza A (H5N1) in Jiangxi Province].

OBJECTIVE: To describe the clinical, laboratory and radiological presentation of a human case infected by influenza A (H5N1), and to understand its management and prognosis. METHODS: The clinical and autopsy data of the first human case infected by influenza A (H5N1) in Jiangxi Province were collected and analyzed. RESULTS: The first case infected by influenza A (H5N1) in Jiangxi Province was confirmed by laboratory findings with reverse transcription-polymerase chain reaction (RT-PCR) and influenza A (H5N1) isolation. The patient had been healthy in the past and exposed to the environment of bird flu before illness. The initial symptoms included high fever with influenza-like symptoms, and then cough and purulent sputum mixed with blood appeared. The clinical situation deteriorated progressively with occurrence of diarrhea and dyspnea. Laboratory abnormalities included decrease of peripheral white blood cells and lymphocytes, urine protein, dramatic increase of enzymes associated with hepatic injury and myocarditis and decrease of serum albumin. Six days later, penicillin-resistant streptococcus pneumoniae was isolated from multiple sputum cultures. With the deterioration of clinical situation, several other bacteria and fungi were found in sputum culture. Pulmonary infiltrates were evident in right middle and lower lobe at day 5 after illness, and rapidly progressed to involve bilateral lungs as acute respiratory distress syndrome (ARDS)-like changes. The patient was treated with antiviral, antibacterial, and antifungal reagents, and corticosteroids and invasive mechanical ventilation were also administered, but without any improvement. The patient died 27 days after the onset of symptoms and an autopsy was performed. Pathologically, the lungs exhibited diffuse alveolar damage. The lymphocytes in the spleen, the lymph nodes and the tonsils were depleted prominently with histiocytic hyperplasia and hemophagocytic phenomena. Edema and degeneration of myocytes in the heart and extensive acute tubular necrosis in the kidney were observed. CONCLUSION: The prognosis was very poor if influenza A (H5N1) infected human cases was developed as ARDS with multiple organ damage or failure.

Isolation and identification of two xylanase-producing extremely alkali-tolerant strains of Bacillus halodurans from Turpan in China.

Bacillus halodurans XJU-1 and XJU-80 were characterized in terms of physiological and biochemical characteristics, and 16S rDNA sequence homology and DNA-DNA hybridization analysis. The two isolates can grow in nutrient broth at a broad range of pH values from 4.5 to 12.6 for XJU-1 and from 3.8 to 12.8 for XJU-80, respectively. And the optimum temperature of growth were around 39 degrees C and 42 degrees C, respectively. Phylogenetic analysis of the two strains based on comparison of 16S rRNA sequence revealed that they are closely related to Bacillus halodurans C-125 and DSM497Twith 99% identity. DNA-DNA hybridization showed that the highest levels of DNA-DNA relatedness were found between the two strains (85%) and the B. halodurans type strains (81.3% and 71.5%), respectively. Moreover, the G + C content of the genomic DNA was 40.5 mol% for XJU-1 and 42.2 mol% for XJU-80.Our results demonstrate that strains XJU-1 and XJU-80 should be classified as two new members of the species B. halodurans.