BACKGROUND:Methicil in-resistant Staphylococcus aureus has been a primary pathogen of nosocomial infections worldwide. To construct a quick and easy knockout method is an important technique of studying virulence and resistance of methicil in-resistant Staphylococcus aureus. OBJECTIVE:To construct the Staphylococcus aureus gene knockout plasmid for understanding the antibiotic resistance and virulence of Staphylococcus aureus. METHODS:pUC19 was considered as a basic skeleton of construction. pLE194Ts temperature-sensitive replicon and tetracycline resistance gene fragment pHY300PLK plasmid in pCL52.1 were bound to EcoR I site in pUC19 by high assurance amplification. Al multiple clone sites in pUC19 were reserved. The Escherichia coli-Staphylococcus aureus shuttle plasmid was obtained. The N315 dapB gene knockout plasmid was obtained through gene knockout technology. This strain was eventual y identified by multiplex-PCR. RESULTS AND CONCLUSION:The Escherichia coli-Staphylococcus aureus shuttle plasmid, pYZ1 and pYZ8, was successful y constructed, and had been used in Staphylococcus aureus gene knockout. Homologous recombinant plasmid pYZ-ΔdapB was constructed by restriction enzyme digestion and overlap technique. After genetical y modification in RN4220, the constructed gene knockout plasmid pYZ-ΔdapB was introduced to N315 to be screened in the low culture temperature. The deletion strain was successful y obtained after being identified by multiplex-PCR. Above data suggested that pYZ1 and pYZ8 can be successful y used for Staphylococcus aureus gene detection, which provides a tool to study resistance and virulence of clinical Staphylococcus aureus strains.

BACKGROUND:Methicil in-resistant Staphylococcus aureus (MRSA) infection had been a global problem up to 1980s, and it has become a leading pathogen giving rise to nosocomial infections now.
OBJECTIVE:To determine the molecular types and drug susceptibilities of Staphylococcus aureus prevailed in burn ward, and to provide a basis for preventing and control ing MRSA intections.
METHODS:A total of 53 Staphylococcus aureus strains were col ected from the burn ward in the Urumqi General Hospital of Lanzhou Military Region of Chinese PLA. These MRSA strains were identified by PCR and cefoxitin disc diffusion test, and al MRSA strains were typed by spa, SCCmec and MLST typing. In the meanwhile, antibiotic susceptibilities of 17 kinds of drugs, such as oxacil in, to Staphylococcus aureus were also determined, and drug resistance of different types of Staphylococcus aureus especial y MRSA, was analyzed.
RESULTS AND CONCLUSION:Among 53 Staphylococcus aureus strains, 43 were identified as MRSA, containing determined for amplification of meoA (n=41) and positive for cefoxitin disc diffusion test (n=2). Three SCCmec types, four spa types, and three ST types were found. The major predominant clone was ST239-MRSA-III-t030 (90.7%), with highest resistant to oxacil in and other nine antibiotics. In conclusion, the higher MRSA isolation rate from the burn ward, and ST239-MRSA-III-t030, as the predominant clone, presents with an outbreak in the burn ward and stronger resistance to many different families of antibiotics.

Objective To analyze and identify the chemical composition in water extracts from Hugu capsule and provide evidence for its pharmacological study and quality control. Methods A HPLC-DAD method was used. The separation was performed on Kromasil C18 column with acetonitrile and 1%glacial acetic acid as mobile phase by gradient elution at a flow rate of 0.8 mL/min. The chemical composition in water extracts from Hugu capsule were identified by comparison with the related chromatographic fingerprint. Results Thirteen characteristic peaks were found in the HPLC chromatographic fingerprint, and four peaks were identified. Conclusion The HPLC-DAD fingerprint expressed the general character of the chemical composition in water extracts from Hugu capsule. It can be used for qualitative analysis of water extracts from Hugu capsule, and improve the quality of Hugu capsule.

Objective:To study the pharmacological action of Vernonia Cinerea(L) Less. Methods: The bacteriostatic test in vitro and the evaluation of effect of Vernonia Cinerea(L) Less. on the propellent function of small intestine of mice, etc were carried out. Results: Vernonia Cinerea(L) Less. prossesses the inhibition on Bacillus coli with lapactic action in vitro, but has the drug resistance to Bacillus dysenteriae and Bacillus coli It can also improve the propellent function of small intestine nomral mice. Conclusions: Vernonia Cinerea(L) Less. is effective for acute gastroenteritis and indigestion clinically.

Objective To design a set of software Gene_Norm for the data processing of genechips by normalization methods. Methods Hybridization spots were divided into two groups: "good" and "bad". Turn on off spots were extracted from the "bad" spots. Normalization processing of data was performed by using average ratio. Results Application of Gene_Norm in the processing of high density microarray data (10 080 spots, 42 records of each spot) resulted in satisfactory processing results. Conclusion The software of genechip can be used to process large amount of data. Some parameters can be chosen manually, so the software is of simple operation and wide application.

Objective To understand the effect of Schistosoma infection on the gestation in mice.\ Methods Female mice infected with Schistosoma japonicum cercariae, and mated with male mice (uninfected) at 40 d and 100 d post\|infection, the changes during pregnant period and the growth of offspring were observed until birth. The serum level of estradiol and progesterone of the infected mice was measured by RIA at oestrus.\ Results The level of estradiol and progesterone, and the pregnant rate were much lower in schistosome infected group than that of the control. The rate of abortion, the mortality of pregnant mice and the death rate due to abortion of infected mice increased significantly. The mortality increased with the time of merging ♀ and ♂mice in one cage prolonged. The body weight and length of the offspring in both infected and control groups were found no significant difference.\ Conclusion The results revealed that schistosome infection may suppress estradiol and progesterone secretion, decrease the rate of pregnancy, and that it may also increase the complications and mortality during the gestation periods.

BACKGROUND:Brahma-related gene 1 (Brg1), a catalytic subunit of an important chromatin remodeling complex, has been considered as a key nuclear transcriptional factor, and tends to be decreased in diabetic cardiomyopathy.
OBJECTIVE:To construct an adenovirus vector carrying Brg1, and observe its protective role in oxidative stress induced-cardiomyocyte apoptosis.
METHODS:The recombinant adenovirus plasmid was linearized and transfected into HEK293 cel s using Fugene HD for packaging and amplification. The adenovirus particles were further purified, quantified, and sequential y transfected to cardiomyocytes of neonatal Sprague-Dawley rats. The Adeno-EGFP transfected and non-transfected cardiomyocytes were used as control group. 24 hours later, the transfection efficiency was observed by fluorescent microscope, and expressions of Brg1 mRNA and protein were detected by quantified PCR and western blotting. After treatment with 100 μmol/L H2O2 for 12 hours, the expressions of Brg1 protein and cleaved-Caspase 3 were measured by western blotting, and cel apoptosis was analyzed by flow cytometry.
RESULTS AND CONCLUSION:(1) The recombinant adenovirus vector of Brg1 had been successful y transfected into cardiomyocytes with higher expressions of Brg1 mRNA and protein, and the transfection efficiency reached more than 90%. (2) After H2O2 treatment, the Brg1 was significantly down-regulated in contrast to the up-regulation of cleaved-Caspase 3;the flow cytometry data showed that the apoptotic cel s were increased. But in Adeno-Brg1 transfected cardiomyocytes, the H2O2 induced cel apoptosis was significantly decreased compared with non-transfected cel s and empty vector transfected cel s. (3) These results suggest that oxidative stress can directly inhibit the Brg1 expression, and overexpression of Brg1 can protect the cardiomyocytes from cel apoptosis induced by oxidative stress.

Background and purpose:The local tumor control rate of non-small-cell lung cancer treated with conventionally fractionated radiotherapy is low.Hypofractionated radiotherapy performed by conformal irradiation techniques can improne the local control rate.But further studies for appropriate fraction dose and toxicity for hypofractionation should be done.The purpose of this study was to prospectively evaluate the safety and efficacy of three-dimensional conformal hypofractionated radiotherapy for non-small-cell lung cancer(NSCLC).Methods:According to the dose-volume histogram(DVH) V_(20), patients were divided into three groups:① V_(20)≤20%,②20%30%,grade Ⅲ RP was observes in 2 of 5 patients and grade Ⅳ RP in 1 patient who died of lung function failure.No grade≥Ⅲ radiation esophagitis was observed.25 patients were evaluated with 8 complete responses,13 partial responses,3 stable diseases and 1 progressive disease.Conclusions:For three-dimensional conformal hypofractionated radiotherapy V_(20) level should be controlled below 30%,the treatment plan with V_(20)≥30% should be changed to palliative treatment.More studies are needed to confirm its efficacy.

Objective: To obtain the diversity and abundance of fast-growing bacteria in the surface water of the northeast coast of Hainan Island in China, different cultivation methods were employed. This study also aims to provide a reference for isolating bacterial samples from seawater sources and preventing marine-derived pathogens. Methods: Based on the principles of taxonomic design, surface seawater samples were collected from six locations along the northeast coast of Hainan Island in China in March, June, October, and December 2021. Then, bacterial enrichment was performed based on traditional cultivation methods for Salmonella, Vibrio, Burkholderia pseudomallei, Actinomycetes, and general marine bacteria. After that, bacterial species identification was conducted by 16S rDNA amplicon sequencing and metagenomic sequencing. Results: A total of 1 151 fast-growing cultivable bacteria belonging to 66 genera and 213 species were identified using five different culture protocols. In different cultivation protocols, Bacillus and Klebsiella demonstrated extensive discriminatory advantages and ranked among the top genera in terms of abundance. Protocol 1 had Escherichia, Klebsiella, and Citrobacter as dominant genera. Pathogenic bacteria detected by protocol 1 included Klebsiella pneumoniae and Escherichia coli, with 37 and 29 strains respectively, while Salmonella enterica was uniquely detected with seven isolates. Proteus, Enterococcus, and Providencia were the dominant genera in protocol 2, and Proteus mirabilis was the most abundant pathogenic bacteria detected with 66 isolates. Vibrio cholerae was uniquely detected with six isolates at a higher abundance. Klebsiella, Escherichia, and Acinetobacter were the dominant genera in protocol 3, and Klebsiella pneumoniae was the most abundant pathogenic bacteria detected with 53 isolates, while Acinetobacter nosocomialis was uniquely detected with seven isolates. Vibrio and Pseudoalteromonas were the dominant genera in protocol 4, and they showed advantages in isolating and cultivating Marine-derived Vibrio. Exiguobacterium, Staphylococcus, and Bacillus were the dominant genera in protocol 5. Bacillus cereus and Lactococcus lactis were the most abundant pathogenic bacteria detected with 20 and 15 isolates, respectively, while Lactococcus lactis was uniquely detected at higher abundance. Metagenomic sequencing showed that Klebsiella pneumoniae was significantly dominant with a gene abundance of 51.11%, followed by Alcanivorax sp. at 12.57%. Conclusion: The surface water of the northeast coast of Hainan Island in China exhibits a rich diversity of bacteria, with Klebsiella pneumoniae being highly abundant in the studied area. Different cultivation methods demonstrate distinct selective advantages in culturing bacterial genera and pathogens. Therefore, it is necessary to optimize cultivation conditions for specific marine bacteria.
Humans ; Water ; Bacteria/genetics* ; Seawater/microbiology* ; Escherichia coli ; Enterococcus ; Klebsiella pneumoniae ; China