Akkermansia muciniphila Protects Against Antibiotic-Associated Diarrhea in Mice.

Probiotics are used to prevent antibiotic-associated diarrhea (AAD) via the restoration of the gut microbiota. However, the precise effects of Akkermansia muciniphila (Akk), which is a promising probiotics, on AAD are unknown. Here, AAD models were established via the administration of lincomycin and ampicillin with or without pasteurized Akk or Amuc_1100 treatment. A diffusion test revealed that Akk was susceptible to the majority of the antibiotics, such as ampicillin. These effects were confirmed by the reduced Akk abundance in AAD model mice. Pasteurized Akk or Amuc_1100 significantly decreased the diarrhea status score and colon injury of AAD model mice. Additionally, these treatments significantly decreased the relative abundance of Citrobacter at genus level and reshaped the metabolic function of gut microbiota. Notably, pasteurized Akk or Amuc_1100 significantly changed the serum metabolome of AAD model mice. In addition, pasteurized Akk or Amuc_1100 suppressed intestinal inflammation by upregulating the expression of GPR109A and SLC5A8 and downregulating the expression of TNFα, IFNγ, IL1ß, and IL6. Furthermore, they enhanced water and electrolyte absorption by upregulating AQP4, SLC26A3, and NHE3. Pasteurized Akk or Amuc_1100 also restored intestinal barrier function by ameliorating the downregulation of ZO-1, OCLN, CLDN4, and Muc2 in AAD model mice. In summary, optimizing intestinal health with pasteurized Akk or Amuc_1100 may serve as an approach for preventing AAD.

Genomic Analysis and Molecular Characteristics in Carbapenem-Resistant Klebsiella pneumoniae Strains.

Klebsiella pneumoniae is an important bacterium and responsible for both infections acquired in hospital and community because of its multidrug resistance and the virulence. The aim of this research was to investigate clonal lineages, antibiotic resistance profiles, and virulence factors of the hospital isolated carbapenem-resistant strains. Fifty carbapenem-resistant isolates were phenotypically confirmed extended-spectrum beta-lactamases ESBLs producers. MLST analysis revealed 94% sequence type 11. These isolates mainly belonged to three clones according to the PFGE DNA patterns. PFGE patterns have good discrimination than ST profiles. One isolate, K. pneumoniae KPX, undergoing whole-genome sequencing comprised one circular chromosome and four circular plasmids. This isolate harbored a variety of antimicrobial resistance and virulence determinants. The closest relative of K. pneumoniae KPX was another ST11 clinical isolate recovered Sichuan. In addition, KPC-2 (98.0%), SHV-11 (98.0%), TEM-1 (76.0%), CTX-M (76.0%), oqxB1(66%), qnrS (70%), Int1 (42.0%), sul1 (82.0%), sul2 (96.0%), iutA (88%), iucC(10%), and rmpA2 (100%) genes were presented in multiple drug-resistant isolates. The dataset presented in this study provided the genomic and epidemiological analysis of carbapenem-resistant K. pneumoniae in hospital settings. Antimicrobial-resistant profiles suggested the presence of significant selective antibiotic pressure. Appropriate surveillance is essential to the development of effective control strategies in the prevention of nosocomial infection.

Methanol-Dependent Carbon Fixation for Irreversible Synthesis of d-Allulose from d-Xylose by Engineered Escherichia coli.

d-Allulose is a rare hexose with great application potential, owing to its moderate sweetness, low energy, and unique physiological functions. The current strategies for d-allulose production, whether industrialized or under development, utilize six-carbon sugars such as d-glucose or d-fructose as a substrate and are usually based on the principle of reversible Izumoring epimerization. In this work, we designed a novel route that coupled the pathways of methanol reduction, pentose phosphate (PP), ribulose monophosphate (RuMP), and allulose monophosphate (AuMP) for Escherichia coli to irreversibly synthesize d-allulose from d-xylose and methanol. After improving the expression of AlsE by SUMO fusion and regulating the carbon fluxes by knockout of FrmRAB, RpiA, PfkA, and PfkB, the titer of d-allulose in fed-batch fermentation reached ≈70.7 mM, with a yield of ≈0.471 mM/mM on d-xylose or ≈0.512 mM/mM on methanol.

Metabolically Engineered Escherichia coli for Conversion of D-Fructose to D-Allulose via Phosphorylation-Dephosphorylation.

D-Allulose is an ultra-low calorie sweetener with broad market prospects. As an alternative to Izumoring, phosphorylation-dephosphorylation is a promising method for D-allulose synthesis due to its high conversion of substrate, which has been preliminarily attempted in enzymatic systems. However, in vitro phosphorylation-dephosphorylation requires polyphosphate as a phosphate donor and cannot completely deplete the substrate, which may limit its application in industry. Here, we designed and constructed a metabolic pathway in Escherichia coli for producing D-allulose from D-fructose via in vivo phosphorylation-dephosphorylation. PtsG-F and Mak were used to replace the fructose phosphotransferase systems (PTS) for uptake and phosphorylation of D-fructose to fructose-6-phosphate, which was then converted to D-allulose by AlsE and A6PP. The D-allulose titer reached 0.35 g/L and the yield was 0.16 g/g. Further block of the carbon flux into the Embden-Meyerhof-Parnas (EMP) pathway and introduction of an ATP regeneration system obviously improved fermentation performance, increasing the titer and yield of D-allulose to 1.23 g/L and 0.68 g/g, respectively. The E. coli cell factory cultured in M9 medium with glycerol as a carbon source achieved a D-allulose titer of ≈1.59 g/L and a yield of ≈0.72 g/g on D-fructose.

Residual and ecological risk assessment of heavy metals in fly ash from co-combustion of excess sludge and coal.

Co-combustion of municipal excess sludge (ES) and coal provides an alternative method for disposing ES. The present study aims to investigate the residual and ecological risk of heavy metals in fly ash from co-combustion of ES and coal. The total concentration and speciation distribution of heavy metals, characterization of SEM, EDX, XRD and leaching test were carried out to assess the fly ash in this study. The results showed that the total concentrations of Cu, Zn and Mn were higher than others in fly ash, and most heavy metals were concentrated in fine particles. For Cd, Cr and Pb, the percentages of speciation of F4 and F5 were all over 90%, suggesting the relatively lower leaching toxicity. The leaching percent of all heavy metals was lower than 5% by two diluted HNO3 solutions for fly ash. The potential ecological risks increased with the decrease of particle size of fly ash, and Cd accounted for the main fraction for ecological risk despite of lower concentration in comparison to other measured heavy metals.

A preliminary study on the homology analysis of clinical Stenotrophomonas maltophilia isolates based on fatty acid profiles.

In order to investigate molecular typing and fatty acid methyl esters (FAMEs) typing of clinical Stenotrophomonas maltophilia (S.maltophilia) isolates based on Random Amplification Polymorphic DNA (RAPD) and Gas Chromatography-Mass Spectrometer (GC-MS) methods, we collected 35 drug-resistant S. maltophilia isolates from March to December 2017 in a comprehensive hospital. The VITEK 2 Compact System was used to determine bacterial antibiotic susceptibility. The analysis of molecular typing was performed by RAPD. GC-MS was used to obtain FAMEs profiles. In total, all 35 isolates were multidrug-resistant S.maltophilia. Their resistance rates to CAZ and LEV were 21.4% and 21.1%, and to SXT up to 13.5%. S. maltophilia isolates were typed to six main clones by RAPD methods and four main clones by FAMEs fingerprint, respectively. The concordance rate of these two methods was 69.0%. Clonal typing provides evidence that multidrug-resistant isolates are prevalent among wards in the hospital. FAMEs profiles may be an easy and sensitive method for bacteria classification. The effectiveness and feasibility of different typing methods should be comprehensively considered.

A purified membrane protein from Akkermansia muciniphila or the pasteurised bacterium blunts colitis associated tumourigenesis by modulation of CD8+ T cells in mice.

OBJECTIVE: Gut microbiota have been linked to inflammatory bowel disease (IBD) and colorectal cancer (CRC). Akkermansia muciniphila (A. muciniphila) is a gram-negative anaerobic bacterium that is selectively decreased in the faecal microbiota of patients with IBD, but its causative role and molecular mechanism in blunting colitis-associated colorectal cancer (CAC) remain inconclusive. This study investigates how A. muciniphila engages the immune response in CAC. DESIGN: Mice were given dextran sulfate sodium to induce colitis, followed by azoxymethane to establish CAC with or without pasteurised A. muciniphila or a specific outer membrane protein (Amuc_1100) treatment. Faeces from mice and patients with IBD or CRC were collected for 16S rRNA sequencing. The effects of A. muciniphila or Amuc_1100 on the immune response in acute colitis and CAC were investigated. RESULTS: A. muciniphila was significantly reduced in patients with IBD and mice with colitis or CAC. A. muciniphila or Amuc_1100 could improve colitis, with a reduction in infiltrating macrophages and CD8+ cytotoxic T lymphocytes (CTLs) in the colon. Their treatment also decreased CD16/32+ macrophages in the spleen and mesenteric lymph nodes (MLN) of colitis mice. Amuc_1100 elevated PD-1+ CTLs in the spleen. Moreover, A. muciniphila and Amuc_1100 blunted tumourigenesis by expanding CTLs in the colon and MLN. Remarkably, they activated CTLs in the MLN, as indicated by TNF-α induction and PD-1downregulation. Amuc_1100 could stimulate and activate CTLs from splenocytes in CT26 cell conditioned medium. CONCLUSIONS: These data indicate that pasteurised A. muciniphila or Amuc_1100 can blunt colitis and CAC through the modulation of CTLs.

A preliminary investigation of metal element profiles in the serum of patients with bloodstream infections using inductively-coupled plasma mass spectrometry (ICP-MS).

BACKGROUND: We determined metal element profiles (MEPs) by inductively-coupled plasma mass spectrometry (ICP-MS) in the serum of patients with blood stream infection (BSI) and find out very important (VIP) metal elements in specific infections. METHODS: Sixty-eight metal elements were identified in both serum and the bacteria isolated from 14 BSI patients with Staphylococcus infection, 39 with Enterobacteriaceae infection, 5 with Enterococcus infection and 58 healthy subjects without infection by ICP-MS methods. Statistical analysis, Principal Component Analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA) were performed to process data among different groups, select differential metal elements and operate correlation analysis. RESULTS: The MEPs in the serum of BSI patients with 4 types of bacteria (Staphylococcus aureus, Escherichia coli, Enterococcus faecium, and Klebsiella pneumonia), and the corresponding MEPs of the bacteria were established. VIP metal elements were screened out in different BSI patients. Correlation analysis showed that there were some correlations between serum concentrations of metal elements and bacterial infection. CONCLUSION: We found differential metal elements in the serum of BSI patients compared with controls, thus providing a basis for the diagnosis, prevention and treatment of BSI from the perspective of metallomics.

Methemoglobin-Based Biological Dose Assessment for Human Blood.

Methemoglobin is an oxidative form of hemoglobin in erythrocytes. The authors' aim was to develop a new biological dosimeter based on a methemoglobin assay. Methemoglobin in peripheral blood (of females or males) that was exposed to a Co source (0.20 Gy min) was quantified using an enzyme-linked immunosorbent assay. The dose range was 0.5-8.0 Gy. In a time-course experiment, the time points 0, 0.02, 1, 2, 3, 7, 15, 21, and 30 d after 4-Gy irradiation of heparinized peripheral blood were used. Methemoglobin levels in a lysed erythrocyte pellet from the irradiated blood of females and males increased with the increasing dose. Methemoglobin levels in female blood irradiated with γ-doses more than 4 Gy were significantly higher than those in male samples at the same doses. Two dose-response relations were fitted to the straight line: one is with the correlation coefficient of 0.98 for females, and the other is with the correlation coefficient of 0.99 for males. The lower limit of dose assessment based on methemoglobin is about 1 Gy. Methemoglobin levels in blood as a result of auto-oxidation increase after 7-d storage at -20 °C. The upregulation of methemoglobin induced by γ-radiation persists for ∼3 d. The absorbed doses that were estimated using the two dose-response relations were close to the actual doses. The results suggest that methemoglobin can be used as a rapid and accurate biological dosimeter for early assessment of absorbed γ-dose in human blood.

An investigation of drug-resistant Acinetobacter baumannii infections in a comprehensive hospital of East China.

BACKGROUND: To investigate the drug resistant gene profiles and molecular typing of Acinetobacter baumannii isolates collected from clinical specimens in a comprehensive hospital, Jiangsu province. METHODS: This study included 120 patients in a comprehensive hospital with drug-resistant A. baumannii infections on clinical specimens from October 2011 to December 2013. Antibiotic susceptibility test was determined by Vitek 2 Compact system. OXA-51, OXA-23, OXA-24, OXA-58, VIM, IMP, SHV, GES, TEM, AmpC, qacEΔ1-sul1, intI l, CarO, aac(6')-Ib, and aac(6')-II were analyzed by PCR. The analysis of molecular typing for 50 multidrug resistant A. baumannii isolates was performed by PFGE. RESULTS: A total of 64(53%) isolates were multidrug-resistant A.baumannii. The antibiotic susceptibility tests showed that the resistant rates to common antibiotics of mutidrug-resistant A. baumannii were extremely high, most of which over 60%. One hundred and ten isolates harbored OXA-51 (91.7%), 100 for OXA-23(83.3%), 103 for VIM-1(85.8%), 90 for AmpC(75.00%), 50 for aac(6')-Ib(41.7%), 77 for the loss of CarO (64.2%), 85 for intl1(70.8%), and 64 for qacEΔ1-sul1(53.33%), while OXA-24 was undetected. Fifty multidrug-resistant A. baumannii isolates belong to 14 clones according to the PFGE DNA patterns. Main clone A includes 24 isolates, while clone B and clone C includes 6 and 9 isolates, respectively and others with no common source identified. CONCLUSION: There is high morbidity of A. baumannii infections in the hospital, especially in ICU and sputum is the most common sample type.The mainly drug-resistant genes of A. baumannii are OXA-51, OXA-23, and VIM-1 in the hospital. Clonal dissemination provides evidence for the prevalence of multidrug-resistant A. baumannii among clinical isolates. It is suggested that there is an urgent need for effective control and prevention measures.

[Effects of chlorides on Cd transformation in a simulated grate incinerator during sludge incineration process ].

The effects of organic chloride-PVC and inorganic chloride-NaCl on Cd partitioning during sludge incineration with adding Cd(CH3COO)2 . 2H2O to the real sludge were investigated using a simulated tubular incineration furnace. And transformation and distribution of Cd were studied in different sludge incineration operation conditions. The results indicated that the partitioning of Cd tended to be enhanced in the fly ash and fule gas as the chloride content increasing. The migration and transformation of Cd-added sludge affected by different chloride were not obvious with the increasing of chloride content. With increasing temperature, organic chloride (PVC) and inorganic chloride (NaC1) can reduce the Cd distribution in the bottom ash. However, the effect of chlorides, the initial concentration and incineration time on Cd emissions had no significant differences. Using SEM-EDS and XRD technique, different Cd compounds including CdCl2, Na2CdCl4, K2CdCl6, K2CdSiO4 and NaCdO2 were formed in the bottom ash and fly ash after adding NaCl to the sludge. In contrast, after adding PVC to the sludge, the Na2CdCl4 and CdCl2 were the main forms of Cd compounds, at the same time, K4CdCI6 and K6CdO4 were also formed. The two different mechanisms of chlorides effects on Cd partitioning were affected by the products of Cd compound types and forms.

[Effects of males' age on sperm apoptosis and DNA integrity].

OBJECTIVE: To explore the correlation of males'age with sperm apoptosis, sperm DNA integrity and other seminal parameters. METHODS: We collected 104 semen samples and divided them into three groups according to the males' age: <35 yr (n = 43), 35 -39 yr (n = 31), and > or = 40 yr (n = 30). Based on the WHO Laboratory Manual (4th ed), we detected the seminal parameters, calculated the percentage of apoptotic sperm by flow cytometry (FCM), determined sperm DNA integrity by Acridine orange staining, and compared the results among the three groups. RESULTS: There were no statistically significant differences among the < 35 yr, 35 -39 yr and > or = 40 yr groups in semen volume ([2.87 +/- 0.89] ml vs [2.98 +/- 1.09] ml vs [2.65 +/- 0.95] ml), sperm concentration ([60.40 +/- 25.43] x 10(6)/ml vs [69.74 +/- 28.33] x 10(6)/ml vs [55.97 +/- 27.22] x 10(6)/ml) (P>0.05). The percentage of progressively motile sperm was significantly lower in the > or = 40 yr ([39.00 +/- 8.35 %) than in the <35 and 35 -39 yr groups ([48.73 +/- 9.89]% and [45.65 +/- 10.55]%) (P<.0.1), and so was the percentage of morphologically normal sperm in the > or = 40 yr than in the < 35 yr group ([11.11 +/- 8.26]% vs [16.43 +/- 8.75 ]%, P<0.01). The percentage of apoptotic sperm was markedly higher in the > or = 40 yr than in the <35 yr group ([11.82 +/- 5.77]% vs [7.04 +/- 3.50]%, P<0.01), while the sperm DNA integrity significantly reduced in the > or = 40 yr group ([75.52 +/- 10.60]%) as compared with the <35 yr ([86.55 +/- 5.60])% and 35 -39 yr group ( [81.39 +/- 8.94]%) (P<0.01). The males' age was correlated positively with the rate of sperm apoptosis (P<0.01), and negatively with sperm DNA integrity and the percentage of progressively motile sperm (P<0.01). CONCLUSION: The advance in males' age increases sperm apoptosis and reduces sperm progressive motility, normal morphology and DNA integrity.

[Influence of male age on the outcome of conventional IVF-ET].

OBJECTIVE: To study the influence of male age on the outcome of conventional IVF-ET. METHODS: Based on male age, 170 couples undergoing conventional IVF-ET were divided into three groups: <35 yr (n = 60), 35 -39 yr (n = 77) and > or = 40 yr (n = 33). We observed the rates of fertilization, cleavage, good quality embryo, implantation, clinical pregnancy and abortion in different groups. RESULTS: There were no significant differences among the three groups in semen volume ([3.10 +/- 1.22] ml vs [2.84 +/- 1.05] ml vs [2.80 +/- 0.79] ml), sperm concentration ([54.23 +/- 26.07] x 10(6)/ml vs [60.27 +/- 24.80] x 10(6)/ml vs [60.21 +/- 27.42] x 10(6)/ml) and sperm viability ([53.93 +/- 13.25]% vs [56.10 +/- 16.58]% vs [51.82 +/- 15.45]%) (P>0.05). The men of the > or = 40 yr group showed a significantly lower percentage of grade a + b sperm ([40.97 +/- 11.91]%) than those of the <35 and 35 - 39 yr groups ([48.47 +/- 11.78]% and [46.84 +/- 13.51]%) (P<0.05), and morphologically normal sperm ([11.76 +/- 5.97]%) than those of the <35 yr group ([15.25 +/- 6.94]% (P<0.05). The rates of fertilization, cleavage, good quality embryo, implantation, clinical pregnancy were 81.52%, 82.61%, 52.33%, 18.06% and 33.33% in the > or = 40 yr group, with no significant differences from those of the <35 yr group (83.18%, 82.68%, 56.99%, 22.40% and 40.00%) and the 35 - 39 yr group (78.78%, 80.66%, 55.01%, 21.74% and 38.96%) (P>0.05), while the abortion rate was markedly increased in the > or = 40 yr group as compared with the <35 yr group (36.36% vs 8.33%, P>0.05). CONCLUSION: Increasing male age is related with decreasing percentages of progressively motile sperm and morphologically normal sperm, but not obviously with the rates of fertilization, good quality embryo, implantation, pregnancy and abortion.

[Expression of SKP2 protein in lung carcinoma and its implication for prognosis].

OBJECTIVE: To investigate the characteristics of SKP2 protein expression in lung carcinoma tissues and its implication for prognosis. METHODS: The expression of SKP2 protein was detected in 89 NSCLC, 13 SCLC, 5 benign lung neoplasms, 5 normal bronchus and lung tissues by tissue chip and immunohistochemical techniques. RESULTS: The positive rate of SKP2 staining was (23.52 +/-13.57)% in NSCLC tissues and (53.85 +/- 12.26)% in SCLC tissues, significantly higher than (2.91 +/- 1.27)% in benign lung neoplasms and normal bronchus and lung tissues. Its expression was highest in SCLC tissues and lowest in benign lung tissues, with a significant difference between them (P <0.01). The expressive level of SKP2 protein in lung carcinoma tissues was closely related to cell differentiation and lymph node metastasis, but not to age, sex, smoking history, tumor site and size, and TNM staging, etc. The survival analysis revealed that the 5-year survival rate of lung carcinoma patients was much lower in SKP2 protein positive expression group than that in negative expression group (P < 0.01). CONCLUSION: The positive expression of SKP2 protein is higher in lung carcinoma than in benign or normal lung tissues, in particular, much higher in SCLC tissue. Moreover, it may be an independent factor to exert negative influence on prognosis of patients with lung carcinoma.

[Sequence analysis of the connexin 26 genes from a deafness family with A1555G mutation in Huaiyin].

OBJECTIVE: To ascertain whether connexin 26 (Cx26) gene was a nuclear modifier gene in an extensive family with matrilineal nonsyndromic deafness associated with A1555G mutation in Huaiyin, China. METHODS: Following PCR-restriction fragment length polymorphism (PCR-RFLP) with ApaI restriction enzyme, Cx26 genes from 26 cases, with A1555G mitochondrial mutations in this family, and 62 controls (including 2 patrilineal relatives, 10 spouse controls and 50 unrelated controls), were sequenced. RESULTS: Compared with the reference sequence of Cx26 gene, totally four kinds of nucleotide changes,79G -->A, 109G-->A, 341G-->A and 235delC, were detected in a heterozygous form. However, the former three were previously reported polymorphisms, and only the 235delC was a previously described recessive mutation associated with most autosomal nonsyndromic sensorineural hearing loss in Japan and China. Further study showed that the heterozygous 235delC mutation existed in both one individual with mild hearing loss and two individuals with normal hearing. Clinical characterization showed that 235delC mutation did not seem to modify the deafness phenotype due to the A1555G mutation. Moreover, this 235delC mutation was deduced to derive from a married-in control. Finally, there were no co-segregation between the phenotypes of hearing loss and the genotypes for Cx26 genes based on the four kinds of nucleotide changes. CONCLUSIONS: The heterozygous 235delC mutation of the Cx26 gene may not modulate the severity of hearing loss associated with A1555G mutation and Cx26 gene is unlikely to be a modifier gene for hearing loss due to A1555G mitochondrial mutation in this Chinese family.

Sequence analysis of the mitochondrial genome from a large family with maternally inherited nonsyndromic deafness.

OBJECTIVE: To ascertain whether other variations coexist with 1555(A--> G) mutation in the mitochondrial DNA and may aggravate the severity of hearing loss or increase the penetrance of 1555(A--> G) mutation in a large family with maternally inherited nonsyndromic deafness in Huaiyin, Jiangsu province. METHODS: PCR-restriction fragment length polymorphism (PCR-RFLP) was used to screen both the nt1555 and the nt7445 of the mitochondrial DNA from 27 maternal members in the core family; and then the mitochondrial genomes from two maternal members, and the 12S rRNA genes MTRNR1 and tRNA-Ser(UCN) gene MTTS1 from the others, were amplified by PCR-RFLP and were sequenced. RESULTS: 1555(A--> G) mutation in the mitochondrial DNA was reverified to be one of the major factors which cause maternally inherited nonsyndromic deafness and the cosegregation of 955-960(insC) and 1555(A--> G) was present in this family. Moreover, 7449 (insG), a novel homoplasmic mutation in the tRNA-Ser(UCN) gene, was found to co-exist with 1555(A--> G) mutation in two maternal members. CONCLUSION: The cosegregation of 955-960(insC) and 1555(A--> G) implies that 955-960(insC) may synergistically cause hearing loss in the presence of an 1555(A--> G) mutation, serving as an aggravating factor to enhance the sensitivity to aminoglycosides, and may sometimes increase the penetrance of 1555(A--> G) mutation.

[Establishment of Immortal Lymphoblastoid Cell Lines of Non-syndromic Deafness Family and Several Methods fro Transforming Human B Lyphocyte by EB virus.].

Reservation of rare family materials is the base for us to do further research. Family of Jiang-Su Huai-Yin is one of the biggest non-syndromic deafness families in the world. In this family,deafness is maternally inherited and all the sufferers have the mitochondrial DNA 12s RNA A1555G mutation. Four methods are used in the experiments for establishing immortal lymphoblastoid cell lines of the family with non-syndromic deafness. Results were as follows: 1 cell line was from small amout of whole blood method, 1 cell line from frozen whole blood method, 14 cell lines from frozen leukocyte method, and 36 cell lines from cyclosporin A method. In this paper, we will discuss these four methods through our experiments of establishing cell lines.

[Mutations analysis in a pedigree with maternally inherited sensorineural hearing loss].

OBJECTIVE: To analyze the mutations in a pedigree with maternally inherited sensorineural hearing loss, and to investigate whether 235delC heterozygote mutation in gap junction protein beta 2 (GJB2) gene modulates the severity of hearing loss associated with the A1555G mitochondrial mutation. METHODS: The PCR products were digested with the Alw26 I restriction enzyme, followed by direct sequencing to detect the mitochondrial mutations in 72 members of a core pedigree of an extensive family with matrilineal nonsyndromic deafness; 235delC mutation of the GJB2 gene was screened in this family by using the Apa I restriction enzyme and direct sequencing. RESULTS: The A1555G mutation of the mitochondrial DNA was present in all 27 members of maternal line, out of them, 21 members had phenotype of deafness (77.8%), with a high penetrance. Only three maternal line members of 72 members possessed 235delC heterozygote mutations, and the three had different phenotypes. CONCLUSION: The A1555G homozygous mutation of mitochondrial DNA is the susceptive etiological factor of nonsyndromic deafness in this family, but in the study of this pedigree, the 235delC heterozygous mutation in GJB2 gene may not aggravate the symptoms of hearing loss associated with the A1555G mitochondrial mutation.