[Respiratory Tract Infection Pathogen Spectrum Study of 376 Pneumoconiosis Inpatients in Chengdu].

OBJECTIVE: To investigate the status of infections caused by respiratory pathogens and the patterns of infections caused by pathogens in different seasons, age groups and stages of pneumoconiosis so as to explore the pathogen spectrum of respiratory tract infections in pneumoconiosis patients. METHODS: The sputum samples of 376 pneumoconiosis patients admitted to an occupational disease hospital in Chengdu between January, 2017 and October, 2019 were collected. Clinical information of the patients was collected and lab tests were conducted to check for 23 kinds of common respiratory viruses, bacteria and fungi in the sputum. The relationship between seasons, ages, and different stages of pneumoconiosis and the pathogen detection rate was analyzed. RESULTS: In the 376 sputum samples, the detection rates of pathogens, viruses, bacteria and fungi were 42.29% (159/376), 32.98% (124/376), 9.57% (36/376) and 6.12% (23/376), respectively. The six pathogens with the highest detection rates were parainfluenza virus, rhinovirus, influenza virus, Candida albicans, Klebsiella pneumoniae and Candida krousei. The severity of respiratory tract infection did not show significant difference in different seasons, age groups, and pneumoconiosis stages. CONCLUSION: The pathogen spectrum of respiratory tract infections in patients with pneumoconiosis is complicated and the proportion of viral infection is high. However, the severity of the infection is not associated with age, seasonal, or pneumoconiosis staging differences.

Study on the Salivary Microbial Alteration of Men With Head and Neck Cancer and Its Relationship With Symptoms in Southwest China.

This study explored the association between oral microbes and head and neck cancer (HNC) as well as symptoms related to patients with HNC before surgical treatment. Fifty-six patients with HNC and 64 matched healthy controls were recruited from West China hospital in Southwest China. The demographic, clinical, and symptom data were collected. Salivary samples were collected to determine the microbial characteristics using 16S rRNA gene sequencing. Patients with HNC presented increased Capnocytophaga abundances. The oral microbial markers as Capnocytophaga (area under the curve=0.81) achieved a high classification power between the HNC patients and healthy controls. Moreover, using Capnocytophaga in conjunction with symptom of voice/speech difficulty achieved an overall predicting accuracy of 92.5% comparing with using Capnocytophaga alone (79.2% accuracy) in distinguishing the HNC patients from healthy controls. Salivary microbial profiles and HNC symptoms may be potential biomarkers for HNC screening.

[Identification of the Strain Which Highly Produces Protease and ß-D-glucosidase Isolated from Shuidouchi Produced in Sichuan and Evaluating Its Ability of Producing Protease].

OBJECTIVE: To select and identify the bacterium which highly produces protease and ß-D-glucosidase from 72 strains of Shuidouchi from Sichuan, and to provide evidence for further research on its nutritional value and fermentation strain exploiting. METHODS: Casein degradation test and pNPG chemical test were applied respectively to detect the capacity to produce protease and ß-D-glucosidase of each strain. Characteristics of morphology, biochemistry, 16S rRNA and MALDI-TOF-MS were used to identify the fermentation strain, which genetic stability, curves of growth and enzyme producing were also obtained. RESULTS: The strain with the highest enzyme activity of ß-D-glucosidase (0.084 U/L) among the top 10 strains for producing protease was selected as the fermentation strain and was identified as Bacillus subtilis, which curves of growth and enzyme producing conformed as well. The result of genetic stability showed that capacity of enzyme producing was stable until the 10th generation. CONCLUSIONS: The fermentation strain which highly produced protease and ß-D-glucosidase was selected from 72 strains of shuidouchi from Sichuan and was identified as Bacillus subtilis.

Microbial diversity and chemical analysis of Shuidouchi, traditional Chinese fermented soybean.

Shuidouchi is a traditional Chinese fermented soybean product and its quality is largely affected by the microbes involved in the fermentation. In this study, eleven Shuidouchi samples were collected from southwest China and the microbial diversity and its correlations with chemical characteristics were investigated. Bacterial community was detected using 16S rRNA sequencing, along with bacterial and fungal viable plate counts. Biogenic amines and other chemical characteristics were determined by HPLC and corresponding chemical reaction methods. Among eleven Shuidouchi samples, 21 phyla and 356 genera were identified. Firmicutes, Bacteroidetes and Proteobacteria were the predominant phyla while Bacillus, Bacteroides and Lactobacillus were the main genera. The average cell number of bacteria, lactic acid bacteria and fungi were 1.6 × 106, 5.9 × 104 and 7.6 × 103 CFU/g, respectively. HPLC results showed that the mean concentration of tryptamine, ß-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine were 23.11, 3.66, 12.21, 7.12, 8.13, 22.98, 24.72, and 39.00 mg/kg, respectively. The average content of other characteristics including amino acid nitrogen, titratable acidity, and reducing sugar were 2.08, 3.44, and 25.78 g/kg, respectively. Shuidouchi samples were slightly acidic or neutral. Fibrinolytic enzyme activity was detected only in one sample. Among top 52 identified genera, 9 genera showed positive correlations with the chemical characteristics of Shuidouchi while 15 genera were negatively associated. Our results indicated that Shuidouchi contained rich microbial resources and were edible safety based on the tested indexes. The associations identified between microbes and chemical characteristics could be further utilized in the food fermentation industry.

In Vitro and In Vivo Evaluation of Antitumor Activity of Ligustrum robustum, A Chinese Herbal Tea.

OBJECTIVE: To examine the effect of the aqueous extract of Ligustrum robustum on tumor growth in vitro and in vivo and explore the possible molecular mechanisms. METHODS: In in vitro study, cell viabilities of human cervical carcinoma cells (HeLa), human breast cancer cells (MCF-7), human prostate cancer cells (PC-3), human hepatoma cells (7721) and human colon carcinoma cells (SW480) were evaluated with cell counting kit-8. For L. robustum-treated Hela cells, early or late apoptosis were evaluated by annexin V/PI staining. Mitochondrial membrane potential was measured by staining cells with JC-1. Apoptosis was monitored by nuclear morphology based on chromatin condensation and fragmentation by 4',6-diamidino-2-phenylinole (DAPI) staining. Caspase-3 and -8 activity levels were measured by a colorimetric assay. In vivo, to evaluate the possible mechanism of L. robustum-mediated antitumor effect, nude mouse xenograft study was also conducted. RESULTS: In in vitro study, L. robustum was found to be toxic to HeLa, MCF-7, PC-3, 7721, SW480, with an half maximal inhibitory concentration value of 2-5 mg/mL (P<0.05). Moreover, externalization of phosphatidylserine, loss of mitochondrial membrane potential, DNA fragmentation and activation of caspase-3 and -8 were detected in L. robustum-treated Hela cells. Using a nude mouse model bearing Hela xenografts, we found that L. robustum reduced tumor volume and tumor weight (P<0.05), but had no effect on body weight and histological damage of important organs. Intraperitoneal injection of L. robustum caused a significant reduction in serum aspartate transaminase and alanine transaminase levels (P<0.05). Furthermore, cleaved caspase-3-positive and terminal nucleotidyl transferase-mediated nick end labeling (TUNEL)-positive cells were observed in L. robustum-treated tumor tissues. CONCLUSIONS: L. robustum inhibits tumor cell growth both in vitro and in vivo by inducing apoptosis in a caspase-dependent way without apparent hepatic toxicity and histological damage, which may offer partial scientific support for the ethnopharmacological claims of L. robustum as a herbal tea for its antitumor activity.

Anticancer activities of Zanthoxylum bungeanum seed oil on malignant melanoma.

ETHNOPHARMACOLOGICAL RELEVANCE: Zanthoxylum bungeanum Maxim. (ZBM), a Chinese herb medicine and food additive, has been shown to have broad-spectrum beneficial effects. However, the anticancer activities of its seed have not been reported. AIM OF THE STUDY: for the first time investigated the anti-proliferation activity of seed oil of ZBM (ZBSO) on melanoma A375 cells as well as the underlying mechanisms. MATERIALS AND METHODS: The chemical composition of ZBSO was analyzed by Ultra Performance Liquid Chromatography. A375 cells exposure at different concentrations of ZBSO to examine the selectivity versus normal skin cells, invasion, apoptosis and cell cycle arrest. Furthermore, transcriptome analysis was employed to investigate potential anticancer mechanisms of ZBSO. RESULTS: Major compounds of ZBSO were identified and unsaturated fatty acid made up the major compound. ZBSO-treated A375 cells showed more typical apoptotic morphologic features than normal cells. ZBSO can significantly inhibit invasion and proliferation of A375 cells by G1 phase arrest and induction of apoptosis. Transcriptome analysis showed that ZBSO may affect cell cycle and MAPK signaling pathway of A375 cells. CONCLUSION: ZBSO possessed anticancer activities that were selectively effective to A375 cells. This study support the hypothesis that ZBSO is a capable candidate for anti-melanoma agent, and provide new insights for future work on investigating the utilization of ZBSO in malignant melanoma treatment.

Prevalence and clinical profile of rotavirus A infection among diarrhoeal children and phylogenetic analysis with vaccine strains in Chengdu, West China, 2009-2014.

OBJECTIVES: Rotaviruses are the most common cause of severe diarrhoeal disease in young children. However, little is known about the epidemiological and clinical profile of rotavirus A (RVA) in diarrhoeal children or the efficacy of Lanzhou lamb rotavirus vaccine (LLR) in Chengdu, China. This study aimed to determine the prevalence and clinical profile of RVA in diarrhoeal children and provide gene analysis information for RVA vaccination programmes. METHODS: A total of 1121 faecal samples were collected from outpatient children with diarrhoea between 2009 and 2014. RT-PCR was performed to detect RVA infection and other gastroenteritis viruses. VP4 and VP7 genes of 13 RVA strains were sequenced to compare their similarity with vaccine strains. RESULTS: The overall RVA infection rate was 17.48%. G1 (54.72%) and G3 (18.87%) were the predominant G genotypes; P[8] (72.36%) and P[4] (11.38%) were the main P genotypes. Sixteen genotypes were identified; G1P[8] (57.33%) and G9P[8] (12.00%) were the most prevalent. The proportion of coinfection with RVA and other gastroenteritis viruses was 18.88%. RVA was mostly detected in winter and in diarrhoeal children 1-2 years of age. The genotypes of Rotarix and RotaTeq vaccines were consistent with RVA strains prevalent in Sichuan and shared high identity. CONCLUSIONS: RVA was one of the major aetiological agents of diarrhoeal children in Chengdu. Genotype distribution differed within each year and the gene analysis implied low efficacy of LLR. Continuous epidemiological monitoring of RVA is essential for the national vaccination programme.

[Detection and Analysis of Human Parainfluenza Virus Infection in Hospitalized Adults with Acute Respiratory Tract Infections].

OBJECTIVE: To investigate the prevalence and gene characteristics of different groups of human parainfluenza virus (HPIV) infection in hospitalized adults with acute respiratory tract infections (ARI). METHODS: RT-PCR was used to detect HPIV hemagglutinin (HA) DNA,which was extracted from sputum samples of 1 039 adult patients with ARI from March,2014 to June,2016. The HA gene amplified from randomly selected positive samples were sequenced to analyze the homology and variation. RESULTS: 10.6% (110/1 039) of these samples were positive for HPIV,including 8 cases of HPIV-1,22 cases of HPIV-2,46 cases of HPIV-3 and 34 cases of HPIV-4. Detectable rate varied among different groups of HPIV according to seasons of the year and ages of patients. No significant differences were found between the positive samples and the reference sequences. Compared with different reference strains of different regions,the genetic distance of nucleotide is the smallest between the strains tested in this study and the reference strains of other provinces and cities in China. CONCLUSION: In Chengdu region,HPIV virus is highly detected in ARI,all subtypes were detected with HPIV-3 being the main subtype.

Human cytomegalovirus prevalence and distribution of glycoprotein B, O genotypes among hospitalized children with respiratory infections in West China, 2009-2014.

OBJECTIVES: Human cytomegalovirus (HCMV) is an important pathogen causing morbidity and mortality in children. HCMV prevalence in children with respiratory infections has not been investigated in West China. Previous studies have suggested that glycoproteins genotypes may be associated with different clinical presentations, but the associations were controversial. The aim of this study was to determine the prevalence of HCMV infection in children with respiratory infections, the distributions of gB, gO genotypes among these isolates and their potential predictive roles for the development of symptoms in children. METHODS: A total of 1709 respiratory specimens were obtained from hospitalised children with respiratory symptoms from 2009 to 2014 for the confirmation of HCMV infection. Glycoprotein B,O genotyping was carried out by multiplex nested PCR and sequencing. RESULTS: The overall infection rate was 10.8%, and dominant genotypes were gB1 (74.2%) and gO1 (37.1%). Clinical characteristics differed between infants and children >1 year of age. Infants infected with HCMV had a higher frequency of fever (P < 0.001), cough (P < 0.001), rhinorrhea (P < 0.001), expectoration (P = 0.001) and diarrhoea (P = 0.005). Children <1 year age infected with gB1 had a higher rate of cough (P = 0.0192). CONCLUSIONS: Infants infected with HCMV had a severe clinical outcome. gB1 may negatively associate with clinical presentations and quality of life in these children. The prevalence of HCMV infection and genotype distribution emphasises the importance of HCMV screening, vaccination and control for transmission.

Effects of Ligustrum robustum on gut microbes and obesity in rats.

AIM: To investigate the anti-obesity and antibacterial effects of Ligustrum robustum (L. robustum) in vivo and in vitro and its possible mechanisms. METHODS: The effects of L. robustum aqueous extract (LR) on various gut bacteria in vitro were evaluated. The effects of LR on high-fat diet-fed (HFD) rats in vivo were also assessed. Culture methods, quantitative polymerase chain reaction, and terminal-restriction fragment length polymorphism were used to analyze the effects of LR on gut bacteria. Biochemical tests were also performed to detect the changes in obesity-related indicators after LR treatment. RESULTS: LR treatment lowered adipose weight and decreased Lee's index, blood glucose, total cholesterol, and lipid in the tested groups relative to control (P < 0.05). To determine the reasons for these changes, we assessed the potential bacteriostatic and bactericidal effects of LR on specific bacterial species in vitro. LR affected the richness, diversity, and evenness of gut bacteria, increased fecal Lactobacillus, and decreased Enterococci in HFD rats (P < 0.05). CONCLUSION: L. robustum may be a safe and effective food for weight loss and obesity control, and the effects of L. robustum might be mediated by the regulation of gut bacteria.

[Isolation and Study on the Aflatoxin Genes of Aflatoxin-producing Fungi in Paprika Samples in Chengdu].

OBJECTIVE: To isolate aflatoxin-producing strains from paprika samples and to do a preliminarily study on the relationship between aflatoxin-producing ability and the genes aflR, omt-1 and ver-1. METHODS: Fungi were isolated by traditional culture method. Potential aflatoxin-producing strains were screened by phenotypic traits and multiplex PCR. After these potential aflatoxin-producing strains cultured in the toxigenic culture medium, the levels of aflatoxin B, (AFB1) of the cultures were tested with ELISA method. The phylogenetic tree of aflR, omt-1 and ver-1 was constructed to explore the relationship between these genes and the AFB1-producing capacity. RESULTS: 17 potential aflatoxin-producing fungi were isolated. The ratio of positive toxigenic strains is 64. 71%. 11 isolates were positive in AFB1 detection while existing high sequence homology with AS 3. 4408, 6 isolates were negative in AFB1 detection while existing high sequence homology with Aspergillus oryzae. CONCLUSION: Aspergillus flavus are potential candidates for aflatoxin control. Not all Aspergillus flavus have AFB1-producing capacity, aflR gene had a direct relation to AFB1-producing capacity, while ver-1 and omt-1 were related to the level of AFB1 producing.

[The Antimicrobial Resistance Analysis of 73 Strains of Streptococcus pneumoniae Isolated from Infant Respiratory Tract].

OBJECTIVE: To preliminary study of the resistance mechanisms of S. pneumoniae (S. pn) by determining the resistance rates and gene of S. pn isolated from the lower respiratory tract infection infants. METHODS: Drug susceptibility test with disk diffusion and broth micro-dilution was conducted to evaluate the resistance rates of 73 strains of S. pn isolated from the lower respiratory tract infection infants to penicillin, levofloxacin and other 10 antibiotics. PCR method was used to analysis the antimicrobial resistant genes tet M, mef A, erm A, erm B and int Tn of the isolates. RESULTS: The antibiotic resistance rates of the S. pn isolates to erythromycin, clindamycin and tetracycline were 95. 9%, 94. 5%, 87. 7% and 0% to vancomycin when tested with disk diffusion method. The antibiotic resistance rates of these isolates to penicillin, cefotaxime and ceftriaxone were 45. 2%, 47. 9% and 46. 6% respectively when tested with broth micro-dilution method. The carrier frequencies of tet M, mef A, erm A, erm B, int Tn genes in the 73 isolates were 91. 8%, 63. 0%, 58. 9%, 39. 7% and 61. 6% respectively. CONCLUSION: The S. pn strains isolated from infant respiratory tract in Chengdu perform a serious drug resistance problem, especially to routine antibiotics like erythromycin, clindamycin and tetracycline and cephalosporin, the resistance rate to levofloxacin, chloramphenicol remained at a low level; the resistance to tetracycline was closely related with the tet M gene fragment, the resistance to macrolide was mainly decided by active efflux pump and secondarily by the alternation of gene targeting, int Tn had close relation with tet M, erm B.

[Non-modified magnetic beads coupled with multiple real-time PCR for detection and quantification of mycotoxigenic fungi in paprika samples].

OBJECTIVE: To establish a method for detecting 3 common toxigenic molds (Aspergillus, Penicillium, and Fusarium) based on non-modified magnetic beads coupled with multiple real-time PCR (NMB-multiple qPCR). METHODS: The primers and genus-specific probes were designed based on the rDNA sequences to develop a multiple real-time PCR using non-modified magnetic bead to enrichment of fungal spores. The sensitivity, specificity and repeatability of this assay were evaluated. RESULTS: The detection limit of this assay for spiked samples was 10(4) CFU/g, demonstrating a 10-fold greater detection sensitivity of this assay than that of real-time PCR. The NMB-multiple qPCR assay also showed good specificity and reproducibility and yielded comparable results with those by traditional colony counting method for spiked samples (P>0.05). CONCLUSION: NMB-multiple qPCR assay we established allows rapid and sensitive detection of common mycotoxigenic fungi in paprika.

[Sequence analysis of G glycoprotein gene of human respiratory syncytial virus].

OBJECTIVE: To understand the variation of G glycoprotein gene of human respiratory syncytial virus (HRSV) obtained from Sichuan in 2010 and determine the dominant genotypes. METHODS: G glycoprotein gene of seven cases of subtype A and eleven cases of subtype B of HRSV were amplified by RT-PCR and sequenced. The phylogenetic trees were constructed to determine the subtype of samples. And then, the genetic variations of the second hypervariable region of G glycoprotein gene were studied. RESULTS: The nucleotide genetic distances of G glycoprotein gene in subtype A and subtype B HRSV were 0.022 +/- 0.005 and 0.073 +/- 0.010, respectively. Transitions were more prevalent than transversions, GA -AG were the most frequent transitions detected among group A viruses, while UC+CU transitions were the most among group B. Phylogenetic analyses demonstrated that 7 subtype A virus could be clustered into one genotype, genotype GA2, and 11 subtype B virus could be clustered into two genotypes, GB2 and BA. The length of G protein gene in group A was all 298aa, but in group B included 295aa, 312aa and 315aa. Selective pressure was purifying selection in both subtypes. 9 positively selected sites in group A and 1 in group B on the second hypervariable region of G protein were identified. CONCLUSION: GA2, GB2 and BA were the main genotype. The changes may favor virus escape from the host immune response including the variation of the G protein gene length, frequency of nucleotide changes and selective pressure.

[Study of molecular epidemiology and genetic diversity of human bocvirus in children with respiratory tract infection].

OBJECTIVE: To investigate the epidemiological features and clinical features of human bocavirus (HBoV) infection in children with respiratory tract infection in Sichuan, and to analysis the HBoV VP1 gene mutation characteristics of Sichuan clinical strains. METHODS: Nasopharyngeal secretions were collected from 787 hospitalized children with respiratory tract infection. PCR was used to detect HBoV. The VP1 genetic variations of the nucleotide and amino acid were analysised respectively. RESULTS: Out of 787 specimens from respiratory tract, 8.26% (65/787) were positive for HBoV, 50.77% (33/65) were co-detected with other respiratory viruses. HBoV is usually detected in children under 3 years of age, the positive rate of male children was higher than female children. Most frequently clinical symptoms of HBoV were cough, fever and expectoration. Phylogenetic analyses showed that all the 8 clinical strains were HBoV1 genetype. GA+AG transitions were the most frequent transitions detected, while the nonsynonymous mutations were more than synonymous mutations. CONCLUSION: HBoV is an important pathogen of respiratory tract infection in children in Sichuan. The main type of nucleotide variation is transitions. Amino acids mutations may relate to immune evasion.

[Gene sequence and antigenic epitope variation within the F protein of respiratory syncytial virus in Sichuan, China].

OBJECTIVE: To investigate the variation of cytotoxic T-lymphocyte (CTL) and neutralizing epitopes in F protein of respiratory syncytial virus (RSV) isolated in Sichuan. METHODS: Nearly full-length of F protein gene of 10 strains of RSV isolated in Sichuan was amplified by RT-PCR and sequenced. The genetic variations, especially the CTL and neutralizing antibody epitopes within different subtypes and genotypes were analyzed and compared. RESULTS: The F protein of RSV is highly conserved within the two subtypes, with the P-distances of nucleotide and amino acids were 0.102 +/- 0.005 and 0.058 +/- 0.006, respectively. Neutralizing epitopes 47F and L4 were conserved between the subtypes, but RS-348 and 7C2 were only conserved within the subtypes. CTL epitopes HLA B * 57, HLA A * 01 and HLA Cw * 12 were conserved only within subtype A. There were specific different sites between the subtypes. CONCLUSION: The sequences of F protein from Sichuan RSV isolates were highly conserved, so as the epitopes on F-protein within subtypes, the identified CLT epitopes in subtype A may not be recognized in subtype B virus.

[A study on carbapenem resistance in klebsiella pneumoniae].

OBJECTIVE: To investigate the molecular mechanisms of reduced carbapenem susceptibility in Klebsiella pneumonia. METHODS: One reduced carbapenem susceptible Klebsiella pneumonia clinical isolate was investigated. Kirby-Bauer disc test was applied to determine the antibiotic susceptibility of the isolate. Modified Hodge Test and EDTA-disk synergy test were used to confirm whether this Klebsiella pneumonia strain could produce metallo-beta-lactamase. The genotype of the beta-lactamase was confirmed by PCR and DNA sequence analysis. Plasmid DNA preparations and conjugation experiment were used to determine the location of the resistant gene. RESULTS: Antibacterial circle of imipenem, meropenem for Klebsiella pneumonia isolate were 16 cm and 17 cm implied that the isolated strain producing carbapenemas. Modified Hodge Test and EDTA-disk synergy test confirmed that this Klebsiella pneumonia isolate produced metallo-beta-lactamase. IMP-4 gene was amplified by PCR and confirmed with sequence analysis. A reduced carbapenem susceptibility in obtained conjugants was observed when evaluated with Kirby-Bauer disc test and conjugation experiment also revealed that blalMP-4 were carried on one plasmid with a size of approximately 73 000 bp. CONCLUSION: Production of plasmid-mediated metallo-beta lactamase IMP-4 might lead to the reduced susceptibility of Klebsiella pneumonia spp. to carbapenems.

Construction and secretory expression of beta-galactosidase gene from Lactobacillus bulgaricus in Lactococcus lactis.

OBJECTIVE: This study is to examine the secretion effects of beta-galactosidase in Lactococcus lactis. METHODS: The usp45 and beta-galactosidase genes were cloned and inserted into plasmid pMG36e to obtain the recombinant plasmid pMG36e-usp-lacZ. This recombinant plasmid was transformed into both Escherichia coli DH5alpha and L. lactis MG1363. The enzyme activity, gene sequencing, SDS-PAGE and hereditary stability were assessed and studied. RESULTS: The lacZ gene inserted into plasmids pMG36e-usp-lacZ was 99.37% similar to the GenBank sequence, and SDS-PAGE revealed an evident idio-strap at 116 KDa between L. lactis MG1363/pMG36e-usp-lacZ in both supernatant and cell samples. Beta-Galactosidase activity measured 0.225 U/mL in L. lactis pMG36e-usp-lacZ transformants, and its secretion rate was 10%. The plasmid pMG36e-usp-lacZ appeared more stable in MG1363. CONCLUSION: The authors concluded that these new recombinant bacteria well expressed and secreted beta-galactosidase, indicating that the beta-galactosidase expression system was successfully constructed, and this might provide a new solution for management of lactose intolerance specifically and promote the use of gene-modified organisms as part of the food-grade plasmid in general.

Analysis of ß-galactosidase production and their genes of two strains of Lactobacillus bulgaricus.

A bacterial ß-galactosidase delivery system is a potential therapy for lactose intolerance. Currently, two Lactobacillus bulgaricus strains with different biological characteristics are under consideration as potential sources. However, differences in these ß-galactosidase genes and their resulting production levels are poorly characterized. The ß-galactosidase ORF of L. bulgaricus yogurt isolate had high variability and was terminated at site 1924 due to a stop codon. However, the full 114 kDa ß-galactosidase band was still resolved by SDS-PAGE, which may indicate that the interrupted ORF was translated into more than one peptide, and they together were folded into the complete enzyme protein that showed much higher ß-galactosidase activity (6.2 U/mg protein) than the enzyme generated from L. bulgaricus reference strain (2.5 U/mg protein).

[Detection and genotyping of rotavirus in diarrhea infant feces in Chengdu].

OBJECTIVE: To study the genotype of rotavirus and the genetic variations of the major neutralization antigen VP4 of group A rotavirus in fecal samples from infants with diarrhea in Chengdu, Sichuan province, China. METHODS: The fecal specimens were collected from infant patients with diarrhea in the spring of 2010 at West China Second University Hospital. Reverse transcription polymerase chain reaction (RT-PCR) was performed to identify rotavirus G serotypes and P genotypes. VP4 gene fragments of the virus were amplified from two strains drawn randomly from the prevailing genotype and cloned into a T-A clone vector to generate the recombinants for sequencing. RESULTS: A group rotaviruses were detected in 13 of 75 specimens (17.3%). Serotype G1 was the predominant type (7/13) and two were serotype G3, four strains' serotypes were unidentified. Analysis of P gene demonstrated that genotype P [8] was the predominant type (6/13), whereas only two P[4] genotype were detected and genotypes for two strains were not determined. G1P [8] was the predominant type of G/P dominance combination (5/13). Sequencing results of the VP4 gene for the analyzed two strains implied that they were genotype P[8] with a 97% homology in sequence. Compared with the standard strain, homologies were also more than 90%. CONCLUSION: Rotavirus is one of the major etiological agents of viral diarrhea among infants in Chengdu. G1 was the dominant type G in Chengdu. G1P[8] was the predominant type of G/P dominance combination.