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1.
Arch Virol ; 169(4): 81, 2024 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-38519716

RESUMO

Bacillus subtilis is a Gram-positive bacterium that is widely used in fermentation and in the pharmaceutical industry. Phage contamination occasionally occurs in various fermentation processes and causes significant economic loss. Here, we report the isolation and characterization of a temperate B. subtilis phage, termed phi18-2, from spore powder manufactured in a fermentation plant. Transmission electron microscopy showed that phi18-2 has a symmetrical polyhedral head and a long noncontractile tail. Receptor analysis showed that phi18-2 recognizes wall teichoic acid (WTA) for infection. The phage virions have a linear double-stranded DNA genome of 64,467 bp with identical direct repeat sequences of 309 bp at each end of the genome. In lysogenic cells, the phage genome was found to be present in the cytoplasm without integration into the host cell chromosome, and possibly as a linear phage-plasmid with unmodified ends. Our data may provide some insight into the molecular basis of the unique lysogenic cycle of phage phi18-2.


Assuntos
Fagos Bacilares , Bacteriófagos , Bacteriófagos/genética , Fagos Bacilares/genética , DNA Viral/genética , Lisogenia , Genoma Viral , Plasmídeos/genética , Citoplasma
2.
Int Orthop ; 48(6): 1645-1655, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38386087

RESUMO

PURPOSE: This study explored the incidence of IRCs used in the procedures of the femur in children with osteogenesis imperfecta (OI) and investigated the independent risk factors of IRCs. METHODS: Three hundred eight-eight cases of surgical data about children with OI were included, who were treated with plate, elastic nail, Kirschner wire and telescopic rod. The choice of different procedures depended on the age of children, the status of femur and the availability of devices. Patient demographics and major IRCs were recorded to compare the outcomes of the four procedures. Then, Cox proportional hazard regression was used to analyse the independent risk factors of IRC, and subgroup analysis was applied to further verify the above results. RESULTS: The total incidence of IRC in the four groups was 90.1% (191/212) for plate, 96.8% (30/31) for Kirschner wire, 87.7% (57/65) for elastic nail and 30.0% (24/80) for telescopic rod. The incidence of IRC in the telescopic rod was lower than that in plate, elastic nail and Kirschner wire (P < 0.001). Cox proportional hazard regression analysis confirmed that procedure was the independent risk factor of IRC (HR, 0.191; 95% CI, 0.126-0.288; P < 0.001), fracture (HR, 0.193; 95% CI, 0.109-0.344; P < 0.001) and deformity (HR, 0.086; 95% CI, 0.027-0.272; P < 0.001). In addition, age of surgery was the independent risk factor of fracture (HR, 0.916; 95% CI, 0.882-0.952; P < 0.001) and deformity (HR, 1.052; 95% CI, 1.008-1.098; P = 0.019). Subgroup analysis confirmed that age of surgery, gender, classification, preoperative state and angle did not affect the effect of telescopic rod on reducing the risk of IRCs. CONCLUSIONS: In our cohort, lower incidence of IRCs was observed in telescopic rod group compared with plate, Kirschner wire and elastic nail. Procedure and age of surgery were independent risk factors of fracture. Likewise, procedure and age of surgery were independent risk factors of deformity, and procedure was independent risk factors of IRC.


Assuntos
Pinos Ortopédicos , Fraturas do Fêmur , Osteogênese Imperfeita , Humanos , Osteogênese Imperfeita/complicações , Osteogênese Imperfeita/cirurgia , Masculino , Feminino , Criança , Incidência , Pré-Escolar , Fatores de Risco , Pinos Ortopédicos/efeitos adversos , Fraturas do Fêmur/cirurgia , Fraturas do Fêmur/epidemiologia , Fraturas do Fêmur/etiologia , Fêmur/cirurgia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Placas Ósseas/efeitos adversos , Lactente , Adolescente , Fios Ortopédicos , Modelos de Riscos Proporcionais
3.
Arch Virol ; 168(1): 17, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36593367

RESUMO

Bacillus subtilis strains play a pivotal role in the fermentation industry. B. subtilis phages can cause severe damage by infecting bacterial cells used in industrial fermentation processes. In this work, we isolated and characterized a Bacillus subtilis-infecting phage, termed phi18. Transmission electron microscopy revealed that phage phi18 particles have typical myovirus morphology, with an icosahedral head connected to a contractile tail. Genomic analysis revealed that the phage genome is a linear double-stranded DNA molecule of 147,298 bp with terminal redundancy of 14,434 bp, and 226 protein coding genes and four tRNA genes were predicted in the genome. Phage-resistant mutants were selected from a mariner transposon-insertion library of B. subtilis 168 in which two bacterial genes, tagE and pgcA, which are required for the glycosylation of wall teichoic acid (WTA), were found to be disrupted, suggesting that WTA is the receptor for phage phi18. Comparative genomic analysis showed that phage phi18 is a new member of the genus Okubovirus of the family Herelleviridae. Finally, general characteristics of the phage-resistant mutants, including biofilm formation, growth, and sporulation, were examined. The results showed that the phage-resistant mutants grew as rapidly as the parental strain B. subtilis 168 at 42 °C, suggesting that these phage-resistant mutants may be used as starters in fermentation processes.


Assuntos
Fagos Bacilares , Bacteriófagos , Bacillus subtilis/genética , Genômica , Bacteriófagos/genética , Genoma Viral , Glicosilação
4.
Acta Biochim Biophys Sin (Shanghai) ; 55(11): 1718-1729, 2023 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-37814815

RESUMO

As a commonly used physical intervention, electrical stimulation (ES) has been demonstrated to be effective in the treatment of central nervous system disorders. Currently, researchers are studying the effects of electrical stimulation on individual neurons and neural networks, which are dependent on factors such as stimulation intensity, duration, location, and neuronal properties. However, the exact mechanism of action of electrical stimulation remains unclear. In some cases, repeated or prolonged electrical stimulation can lead to changes in the morphology or function of the neuron. In this study, immunofluorescence staining and Sholl analysis are used to assess changes in the neurite number and axon length to determine the optimal pattern and stimulation parameters of ES for neurons. Neuronal death and plasticity are detected by TUNEL staining and microelectrode array assays, respectively. mRNA sequencing and bioinformatics analysis are applied to predict the key targets of the action of ES on neurons, and the identified targets are validated by western blot analysis and qRT-PCR. The effects of alternating current stimulation (ACS) on neurons are more significant than those of direct current stimulation (DCS), and the optimal parameters are 3 µA and 20 min. ACS stimulation significantly increases the number of neurites, the length of axons and the spontaneous electrical activity of neurons, significantly elevates the expression of growth-associated protein-43 (GAP-43) without significant changes in the expression of neurotrophic factors. Furthermore, application of PI3K/AKT-specific inhibitors significantly abolishes the beneficial effects of ACS on neurons, confirming that the PI3K/AKT pathway is an important potential signaling pathway in the action of ACS.


Assuntos
Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Neurônios/metabolismo , Transdução de Sinais , Crescimento Neuronal/fisiologia , Células Cultivadas
5.
BMC Musculoskelet Disord ; 24(1): 110, 2023 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-36759791

RESUMO

BACKGROUND: Osteogenesis imperfecta (OI) is a hereditary genetic disorder characterized by bone fragility and extremity deformities. The surgical management for long-bone fractures and deformities in OI remains a challenge. We aimed to compare clinical outcomes after femoral surgery splinted with the telescopic rod, the plate and screws, the elastic nail and the non-elongating rod in setting of OI. METHODS:  A retrospective cohort study included 783 femoral procedures (mean age 6.00 (interquartile range (IQR) 5.00) years, 335 (42.8%) females) was conducted, and individuals were categorized into four groups according to implants. After verifying comparability among the groups, revision rate and implant survival period were compared among the Sillence types and the same comparison were made among four groups within each Sillence type. The incidence of refractures, deformities, and implant-related complications were also compared among the four groups. RESULTS: There were no significant differences in demographic information among the four groups in terms of sex (p = 0.101), laterality (p = 0.587), Sillence type (p = 0.122), and postoperative follow-up period (p = 0.214). In total, children with Sillence type III had the highest revision rate and the shortest implant survival period; children with Sillence type I had the lowest revision rate and the longest implant survival period; and children with Sillence type IV had the revision rate and the implant survival period between those observed in Sillence types I and III. In Sillence types III and IV, the telescopic rod had lower revision rate (III 24.8%; IV 20.9%) compared to the plate (III 97.2%, p<0.001; IV 80.3%, p<0.001), the elastic nail (III 100.0%, p=0.019; IV 73.9%, p<0.001) and the non-elongating rod (III 65.0%, p<0.001; IV46.9%, p<0.001); the median implant survival period of the telescopic rod (III 48.00 (IQR 28.50) months; IV 43.00 (33.00) months) is longer than the plate (III 11.00 (9.00) months, p<0.001; IV 19.00 (20.00) months, p<0.001), the elastic nail (III 45.00 (37.75) months, p=1.000; IV 19.00 (35.00) months, p=0.028) and the non-elongating rod (III 39.00 (31.75) months, p=0.473; IV 38.50 (29.75) months, p=1.000).A similar trend was observed in Sillence type I (p = 0.063, p = 0.003; respectively). In addition, the incidence of refracture (15.5%), deformity (2.8%) and implant-related complications (23.1%) were also statistically lower in the telescopic rod group. CONCLUSION: In our cohort, lower revision rate and longer implant survival period were observed in telescopic rod group. This was mainly due to the significant lower incidence of refracture, deformity and implant-related complications with the use of telescopic rod.


Assuntos
Osteogênese Imperfeita , Feminino , Criança , Humanos , Pré-Escolar , Masculino , Osteogênese Imperfeita/cirurgia , Osteogênese Imperfeita/complicações , Estudos Retrospectivos , Fêmur/cirurgia , Próteses e Implantes , Placas Ósseas , Complicações Pós-Operatórias
6.
Arch Virol ; 167(12): 2689-2702, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36194307

RESUMO

Escherichia coli is an important foodborne pathogen that can cause severe human disease. Here, we report the isolation and characterization of the lytic virus phi2013, which is specific for Escherichia coli laboratory strains. Transmission electron microscopy showed that phage phi2013 has an icosahedral head and a long, fragile, noncontractile tail, exhibiting the typical form of a siphovirus. Evidence revealed that the phi2013 genome is a linear double-stranded DNA molecule of 49,833 bp with 79 predicted genes without any known antibiotic resistance genes, virulence factor genes, or integrase genes. Moreover, the conserved outer membrane protein FhuA, which is present in members of several genera of the family Enterobacteriaceae, was identified as the receptor of phage phi2013. To evaluate the potential of phage phi2013 as a biocontrol agent for controlling E. coli contamination, it was tested in several foods, including sterilized milk, ready-to-eat beef, and crisphead lettuce. The data showed that phage phi2013 can efficiently inhibit E. coli growth in the tested foods at 4°C and 25°C. We therefore conclude that phage phi2013 or cocktails containing phi2013 may be used as an antimicrobial agent in extending the shelf-life of food products by effectively controlling the growth of E. coli.


Assuntos
Bacteriófagos , Escherichia coli , Bovinos , Animais , Humanos , Escherichia coli/genética , Colífagos/genética , Bacteriófagos/genética , Genômica , Genoma Viral
7.
Biochem Biophys Res Commun ; 553: 107-113, 2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-33765554

RESUMO

Chronic social defeat stress (CSDS) is widely applied to study of depression in rodents. 10-day CSDS was a most commonly employed paradigm but with high resilience ratio (∼30%), producing potential variation in depression-like behavioral symptoms. Whether prolonged period (21 days) of CSDS would promote less resilience and reduce behavioral variability remains unknown. We applied 10-day and 21-day CSDS paradigms to induce mouse model of depression and compared their resilience ratio and behavioral phenotypes. Mice under 21-day CSDS had significantly lower resilience ratio and greater changes in behavioral indicators relative to mice under 10-day CSDS. Behavioral indicators from 21-day CSDS paradigm had higher correlations and better prediction for susceptibility which indicating higher uniformity in behavioral phenotypes. Furthermore, a subset of behavioral indicators in 21-day CSDS had high prediction efficacy and should be first applied to screen susceptibility of CSDS. Thus, our study demonstrates that 21-day CSDS is a more robust paradigm inducing reliable depression-like behaviors relative to 10-day CSDS, and should be preferentially used in rodent studies of depression.


Assuntos
Depressão/psicologia , Resiliência Psicológica , Derrota Social , Estresse Psicológico/psicologia , Animais , Doença Crônica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo
8.
Arch Virol ; 164(3): 893-896, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30560292

RESUMO

Members of the bacterial genus Aeromonas are important aquatic pathogens that cause severe fish diseases. Here, we characterize a novel lytic phage, Aeromonas virus phiA8-29, isolated from the alimentary tract of a freshwater fish. Transmission electron microscopy showed that phiA8-29 has a long contractile tail and thus can be classified as a member of the family Myoviridae. The phage genome was identified as a double-stranded DNA molecule of 144,974 bp containing 185 open reading frames and nine tRNA-encoding genes. Comparative genomic analysis revealed that the phiA8-29 genome has little similarity to any of the currently sequenced Aeromonas phage genomes. Our data indicate that phiA8-29 is a novel lytic Myoviridae phage that does not belong to any of the known genera.


Assuntos
Aeromonas/virologia , Bacteriófagos/isolamento & purificação , Myoviridae/isolamento & purificação , Bacteriófagos/classificação , Bacteriófagos/genética , Bacteriófagos/ultraestrutura , Genoma Viral , Myoviridae/classificação , Myoviridae/genética , Myoviridae/ultraestrutura , Fases de Leitura Aberta , Filogenia , Proteínas Virais/genética
9.
Biofouling ; 35(5): 541-550, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31269803

RESUMO

Biofilm formation is an important virulence factor which is controlled by complex regulatory circuits in Pseudomonas aeruginosa. In this work, a biofilm hyper-producing strain, P2-7, was selected from a collection of transposon insertion mutants in which the PA2121 gene was disrupted. PA2121 was predicted as a putative LysR-type regulator. Analyses showed that it was involved in early biofilm formation, mature biofilm development, and colony morphology. Quantitative measurements revealed that PA2121 repressed biosynthesis of extracellular polysaccharides (alginate, psl and pel). Furthermore, it was observed that PA2121 was self-regulated, highly expressed in the early phase of biofilm development, and subject to the negative regulation by a biofilm synthesis regulator SrpA that binds directly to the PA2121 gene promoter. Collectively, this study proposes that PA2121 is a novel biofilm synthesis repressor (BsrA) in P. aeruginosa.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes , Pseudomonas aeruginosa/fisiologia , Fatores de Transcrição/metabolismo , Alginatos/metabolismo , Regulação Bacteriana da Expressão Gênica , Polissacarídeos Bacterianos/biossíntese
10.
Arch Virol ; 163(9): 2377-2383, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29749589

RESUMO

Phage O4 of Pseudomonas aeruginosa was previously visualized as a short-tailed virus using a transmission electron microscope. In this work, the O4 genome was characterized to be a linear dsDNA molecule comprising 50509 bp with 76 predicted genes located in five clusters. Mass spectrometry showed that the O4 virion contains 6 putative structural proteins, 2 putative enzymes, and 7 hypothetical proteins. By analyzing a Tn5G transposon mutation library, eight genes, wbpR, wbpV, wbpO, wbpT, wbpS, wbpL,  galU, and wzy, were identified and confirmed responsible for the phage-resistant phenotype; all of them are related to the synthesis of O-specific antigen (OSA) of lipopolysaccharide (LPS), indicating that OSA is the receptor for the adsorption of phage O4. Comparative genomic analysis revealed that the phage O4 genome shares little similarity to any known podovirus, indicating that phage O4 is classifiable as a novel member of the Podoviridae family.


Assuntos
Genoma Viral , Lisogenia/fisiologia , Podoviridae/genética , Fagos de Pseudomonas/genética , Pseudomonas aeruginosa/virologia , Receptores Virais/metabolismo , Proteínas Virais/genética , DNA/genética , DNA/metabolismo , Elementos de DNA Transponíveis , DNA Viral/genética , DNA Viral/metabolismo , Ontologia Genética , Anotação de Sequência Molecular , Antígenos O/química , Antígenos O/metabolismo , Filogenia , Podoviridae/classificação , Podoviridae/metabolismo , Fagos de Pseudomonas/classificação , Fagos de Pseudomonas/metabolismo , Receptores Virais/química , Análise de Sequência de DNA , Proteínas Virais/metabolismo , Vírion/genética , Vírion/metabolismo
11.
J Basic Microbiol ; 57(2): 162-170, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27714824

RESUMO

Bacterial growth phase has been reported affecting phage infection. To underpin the related mechanism, infection efficiency of Pseudomonas aeruginosa phage K5 is characterized. When infecting the logarithmic cells, phage K5 produced significantly more infection centers than the stationary cells, well concordant with the viable cell ratio in the different growth phases. Additionally, the burst size decreased dramatically in the stationary cells, implying that the physiological state of the viable cells contributed to the productivity of phage K5, and it was consistent with the expression variation of the phage RNA polymerase. Quorum sensing inhibitor penicillic acid was applied and could significantly improve the viable cell proportion and the infection center numbers, but had less effect on the corresponding burst sizes. Moreover, the effect of penicillic acid and the quorum sensing regulator mutants on the production of phage C11 was also analyzed. Taken together, our data suggest that quorum sensing is involved in the defense of phage K5 infection by influencing the viable cell population and their physiological state, and it is an efficient and intrinsic pathway allowing bacteria to resist phage attacks in natural environment.


Assuntos
Interações Hospedeiro-Parasita , Fagos de Pseudomonas/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Pseudomonas aeruginosa/virologia , Percepção de Quorum
12.
Zhongguo Dang Dai Er Ke Za Zhi ; 19(7): 763-769, 2017 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-28697828

RESUMO

OBJECTIVE: To investigate the relationship of KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) with acute respiratory infection in children in Tianjin, China. METHODS: A total of 3 730 nasopharyngeal secretions were collected from hospitalized children with acute respiratory infection in Tianjin Children's Hospital from January 2011 to December 2013. Viral nucleic acid was extracted, and virus infection (KIPyV and WUPyV) was determined by PCR. Some KIPyV-positive and WUPyV-positive PCR products were subjected to sequencing. Sequencing results were aligned with the known gene sequences of KIPyV and WUPyV to construct a phylogenetic tree. Amplified VP1 fragments of KIPyV were inserted into the cloning vector (PUCm-T) transformed into E. coli competent cells. Positive clones were identified by PCR and sequencing. The nucleotide sequences were submitted to GenBank. In addition, another seven common respiratory viruses in all samples were detected by direct immunofluorescence assay. RESULTS: In the 3 730 specimens, the KIPyV-positive rate was 12.14% (453/3 730) and the WUPyV-positive rate was 1.69% (63/3 730). The mean infection rate of KIPyV was significantly higher in June and July, while the mean infection rate of WUPyV peaked in February and March. Most of the KIPyV-positive or WUPyV-positive children were <3 years. The co-infections with KIPyV, WUPyV, and other respiratory viruses were observed in the children. The co-infection rate was 2.31% (86/3 730) and there were nine cases of co-infections with WUPyV and KIPyV. Thirty-five KIPyV-positive and twelve WUPyV-positive PCR products were sequenced and the alignment analysis showed that they had high homology with the known sequences (94%-100% vs 95%-100%). The VP1 gene sequences obtained from two KIPyV strains in this study were recorded in GenBank with the accession numbers of KY465925 and KY465926. CONCLUSIONS: For some children with acute respiratory infection in Tianjin, China, the acute respiratory infection may be associated with KIPyV and WUPyV infections. KIPyV infection is common in summer, and WUPyV infection in spring. The epidemic strains in Tianjin have a high homology with those in other regions.


Assuntos
Polyomavirus/isolamento & purificação , Infecções Respiratórias/virologia , Doença Aguda , Adolescente , Criança , Feminino , Humanos , Masculino , Epidemiologia Molecular , Polyomavirus/genética , Infecções por Polyomavirus/epidemiologia
13.
J Basic Microbiol ; 56(12): 1344-1353, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27632947

RESUMO

Phage genomic information and the nature of host-phage interactions are important for phage applications. In this study, Pseudomonas aeruginosa phage K5 is characterized as a linear double-stranded genomic DNA molecule of 93,754 bp with identical 1182-bp direct terminal repeats. Comparative genomic analysis reveals that phage K5 is highly homologous to the "PaP1-like" phages. Thirteen mutants resistant to phage K5 are screened in a transposon mutant library. The disrupted genetic loci are identified as gene Y880_RS05480 encoding a putative O-antigen polymerase Wzy and gene wapH encoding a glycosyltransferase. The mutants are confirmed by the complementation experiment. The production of biofilm and the profile of lipopolysaccharide (LPS) are further analyzed in the Y880_RS05480 mutant. Our data indicate that LPS is the receptor of phage K5.


Assuntos
Genoma Viral , Antígenos O/metabolismo , Fagos de Pseudomonas/genética , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/virologia , Receptores Virais/genética , Sequência de Aminoácidos , Biofilmes/crescimento & desenvolvimento , Elementos de DNA Transponíveis , DNA Viral/genética , Teste de Complementação Genética , Glicosiltransferases/genética , Hexosiltransferases/genética , Interações Hospedeiro-Patógeno , Mutação , Antígenos O/química , Proteínas Associadas a Pancreatite , Pseudomonas aeruginosa/fisiologia , Análise de Sequência de DNA
14.
Zhongguo Dang Dai Er Ke Za Zhi ; 18(1): 39-43, 2016 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-26781411

RESUMO

OBJECTIVE: To detect human bocavirus (HBoV) and investigate its genetic and evolutionary characteristics in children with acute respiratory infection in Tianjin, China. METHODS: A total of 1,259 samples of nasopharyngeal aspirates were collected from children with a confirmed diagnosis of acute respiratory infection between January and December, 2012. Viral nucleic acid was extracted, HBoV was detected by real-time quantitative PCR, and the gene segments of nucleocapsid protein of HBoV in positive samples were amplified by PCR. Several products were randomly selected and sequenced.The sequence obtained was compared with the known sequence of HBoV, and a phylogenetic analysis was performed. All the samples were examined to detect for other common respiratory tract viruses. RESULTS: Among the 1,259 samples, the positive rate of HBoV was 4.53% (57/1,259), and among the 57 samples with positive HBoV, 75% (43/57) were positive in children with an age of 6-36 months. The positive rate of HBoV in children peaked in summer (from June to August), and there was a mixed infection with other viruses. Sequence analysis was performed for the PCR products from 36 positive samples, and the presence of HBoV was confirmed, with a higher homology to the known sequence of HBoV. CONCLUSIONS: In Tianjin, acute respiratory infection in some children may be associated with HBoV infection, which is commonly seen in infants with an age of 6-36 months. The peak of HBoV infection occurs in summer. The phylogenetic analysis shows a high homology to the known sequence of HBoV, with few gene sequence variations.


Assuntos
Bocavirus/isolamento & purificação , Infecções Respiratórias/virologia , Bocavirus/classificação , Criança Hospitalizada , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Filogenia , Reação em Cadeia da Polimerase , Estações do Ano
15.
J Phys Chem A ; 118(25): 4484-93, 2014 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-24892389

RESUMO

The binding energy spectra and electron momentum distributions for the outer-valence molecular orbitals of gaseous cyclopropylamine (CPA) have been measured by (e, 2e) electron momentum spectrometer employing noncoplanar asymmetric geometry at the impact energy of 2500 eV. The experimental results are interpreted on the basis of the quantitative calculations of the ionization energies and the relevant molecular orbitals at benchmark theoretical levels using the outer-valence Green's function method, the symmetry-adapted cluster configuration interaction method, and the density functional theory with B3LYP hybrid functional. The total energies of the trans and gauche conformers of CPA are also calculated by the second-order Møller-Plesset perturbation theory with large basis sets and the derived enthalpy differences (2.02-2.12 kcal/mol) are consistent with the previous experimental data (2.19 kcal/mol). The theoretical binding energy spectra and electron momentum distributions, in which the relative abundances of trans and gauche are taken into account, are generally in accordance with the experimental results except for the ionization band from the trans 8a' and gauche 11a orbitals. The discrepancy is explained qualitatively in view of the picture of molecular geometry change at the instant of ionization.

16.
Biotechnol Lett ; 36(5): 969-73, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24375234

RESUMO

A newly-isolated strain of Serratia marcescens, G12, was characterized for 2,3-butanediol (2,3-BD) production. In shake-flask and batch fermentations, 2,3-BD reached 48.5 and 51 g l(-1), respectively. Low amounts of (~8 g l(-1)) of acetoin were also formed. In fed-batch fermentations, strain G12 produced 72.8 g 2,3-BD l(-1) with glucose initially at 130 g l(-1). When aeration rate was increased to 2.5 vvm for the fermentation process, 2,3-BD reached 87.8 g l(-1) and the highest productivity was 1.6 g l(-1 )h(-1). Acetoin was at 6.2 g l(-1). G12 therefore may be a suitable candidate strain for large-scale production of 2,3-BD.


Assuntos
Reatores Biológicos/microbiologia , Butileno Glicóis/metabolismo , Serratia marcescens/metabolismo , Acetoína/análise , Acetoína/metabolismo , Butileno Glicóis/análise , Fermentação , Serratia marcescens/isolamento & purificação
17.
J Ind Microbiol Biotechnol ; 41(8): 1267-74, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24879481

RESUMO

The 2,3-butanediol (2,3-BD) dehydrogenase gene budC of Serratia marcescens G12 was disrupted to construct the acetoin (AC) producing strain G12M. In shake-flask cultures, AC production was enhanced by increased concentrations of glucose or sodium acetate in G12M. In fed-batch fermentation, G12M produced 47.5 g/L AC along with 9.8 g/L 2,3-BD. The expression of the key enzymes for AC synthesis was further investigated. Alpha-acetolactate synthase gene budB decreased its expression significantly in G12M compared with G12. This probably explained the moderate AC production in G12M cultures. Additionally, overexpression of budB gene and α-acetolactate decarboxylase gene budA was conducted in G12M and no significant increase of AC was observed. The results suggested that intracellular AC accumulation might inhibit the expression of budB and budA gene and induce budC gene expression in G12M. Our analyses offered the bases for further genetic manipulations in improving AC production in microbial fermentations.


Assuntos
Acetoína/metabolismo , Oxirredutases do Álcool/genética , Reatores Biológicos , Vias Biossintéticas/fisiologia , Serratia marcescens/fisiologia , Acetoína/farmacologia , Carboxiliases/genética , Primers do DNA/genética , Fermentação , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Técnicas de Inativação de Genes , Glucose , Microbiologia Industrial/métodos , Mutação/genética , Plasmídeos/genética , Serratia marcescens/genética , Serratia marcescens/metabolismo , Acetato de Sódio
18.
Int J Food Microbiol ; 411: 110525, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38128262

RESUMO

Pseudomonas fluorescens is a common spoilage causing microbe found in milk. Antibiotic preservatives may cause emergence of multidrug resistance, posing food safety related risks to public health. Phage treatment may be used as an alternative to antibiotics in controlling P. fluorescens contaminations. Here we reported that P. fluorescens phage phiGM22-3 reproduced rapidly over a broad temperature range of 4 through 30°C, and the optimum growth of phiGM22-3 occurred at 10°C, indicating that it was a psychrophilic virus. Genome analysis revealed that phiGM22-3 has a genome of 42,662 bp with an identical terminal direct repeat sequence of 328 bp and encodes 58 predicted proteins. Evidence revealed that phiGM22-3 recognized lipopolysaccharides (LPS) as receptor for infection. Additionally, two phage mutants phiMX2 and phiMX8 with different host ranges were identified in the phiGM22-3 population. Phage killing efficiency of P. fluorescens cells artificially inoculated in milk was evaluated. Phage phiGM22-3 and the cocktails containing phiMX2 and phiMX8 can lyse almost 100% bacterial cells at 4°C within 24 h. Taken together, our data indicated that the psychrophilic virus phiGM22-3 and its two mutants can efficiently inhibit bacteria growth at 4°C, showing a great potential to be used as alternatives to conventional antibiotics against P. fluorescens in refrigerated foods.


Assuntos
Bacteriófagos , Pseudomonas fluorescens , Animais , Bacteriófagos/genética , Leite/microbiologia , Microbiologia de Alimentos , Antibacterianos
19.
Appl Microbiol Biotechnol ; 97(18): 8163-71, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23649353

RESUMO

Household anaerobic digesters have been installed across rural China for biogas production, but information on methanogen community structure in these small biogas units is sparsely available. By creating clone libraries for 16S rRNA and methyl coenzyme M reductase alpha subunit (mcrA) genes, we investigated the methanogenic consortia in a household biogas digester treating swine manure. Operational taxonomic units (OTUs) were defined by comparative sequence analysis, seven OTUs were identified in the 16S rRNA gene library, and ten OTUs were identified in the mcrA gene library. Both libraries were dominated by clones highly related to the type strain Methanocorpusculum labreanum Z, 64.0 % for 16S rRNA gene clones and 64.3 % for mcrA gene clones. Additionally, gas chromatography assays showed that formic acid was 84.54 % of the total volatile fatty acids and methane was 57.20 % of the biogas composition. Our results may help further isolation and characterization of methanogenic starter strains for industrial biogas production.


Assuntos
Reatores Biológicos/microbiologia , Esterco/microbiologia , Metano/metabolismo , Methanomicrobiales/isolamento & purificação , Methanomicrobiales/metabolismo , Anaerobiose , Animais , Proteínas Arqueais/genética , China , DNA Arqueal/genética , Esterco/análise , Methanomicrobiales/classificação , Methanomicrobiales/genética , Dados de Sequência Molecular , Oxirredutases/genética , Filogenia , RNA Ribossômico 16S/genética , Suínos
20.
J Orthop Surg Res ; 18(1): 532, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37496046

RESUMO

OBJECTIVE: To investigate the patient-related factors that affect the revision rate for the tibia in patients with osteogenesis imperfecta treated with the Peter-Williams nail, and to explore the relationship between the risk factors and complications postsurgery. METHODS: We retrospectively analysed the data of 211 patients (93 females (44.08%) and 118 males (55.92%)) with osteogenesis imperfecta treated with Peter-Williams. The factors affecting surgical revision were analysed by performing binary logistic regression. Then, a total of 211 patients with type III, type I or type IV OI were divided into five groups according to the results of regression. Statistical comparison of these groups was performed to further investigate the relationship between patient-related factors and revision procedures. Statistical comparison was also performed to analyse the relationship between the classification and postoperative complications. RESULTS: Among the 211 patients who underwent surgery, 40 had type I OI, 109 had type IV OI, and 62 had type III OI. Binary logistic regression revealed that the classification (OR = 3.32, 95% CI 1.06-10.39, P = 0.039) and initial operation age (OR = 0.83, 95% CI 0.76-0.92, P < 0.001) were significantly correlated with revision procedures. In type III patients, the initial operation age was significantly correlated with revision procedures (P < 0.001), and the revision rate was lower in patients aged 9 to12 years (P = 0.001). In type I and IV patients, the initial operation age was not significantly correlated with revision procedures (P = 0.281). Classification had a significant effect on postoperative deformity (P = 0.003). CONCLUSIONS: The study reported that the age of initial surgery and classification were the influencing factors affecting the revision procedures of tibia in patients with osteogenesis imperfecta treated with the Peter-Williams nail. In patients with type III disease, the revision rate was lower individuals aged 9-12 years old, and a higher incidence of postoperative deformity was observed.


Assuntos
Osteogênese Imperfeita , Tíbia , Masculino , Feminino , Humanos , Criança , Tíbia/cirurgia , Osteogênese Imperfeita/cirurgia , Osteogênese Imperfeita/complicações , Osteogênese Imperfeita/epidemiologia , Estudos Retrospectivos , Reoperação , Fatores de Risco
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