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1.
Proc Natl Acad Sci U S A ; 118(11)2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33836615

RESUMO

Gram-positive bacteria assemble a multilayered cell wall that provides tensile strength to the cell. The cell wall is composed of glycan strands cross-linked by nonribosomally synthesized peptide stems. Herein, we modify the peptide stems of the Gram-positive bacterium Bacillus subtilis with noncanonical electrophilic d-amino acids, which when in proximity to adjacent stem peptides form novel covalent 5,3-cross-links. Approximately 20% of canonical cell-wall cross-links can be replaced with synthetic cross-links. While a low level of synthetic cross-link formation does not affect B. subtilis growth and phenotype, at higher levels cell growth is perturbed and bacteria elongate. A comparison of the accumulation of synthetic cross-links over time in Gram-negative and Gram-positive bacteria highlights key differences between them. The ability to perturb cell-wall architecture with synthetic building blocks provides a novel approach to studying the adaptability, elasticity, and porosity of bacterial cell walls.


Assuntos
Parede Celular/química , Bacilos Gram-Positivos/química , Peptidoglicano/química , Aminoácidos/química , Aminoácidos/metabolismo , Bacillus subtilis/química , Bacillus subtilis/citologia , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Parede Celular/metabolismo , Bactérias Gram-Negativas/química , Bactérias Gram-Negativas/citologia , Bactérias Gram-Negativas/metabolismo , Bacilos Gram-Positivos/citologia , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/metabolismo , Peptidoglicano/metabolismo , Peptidil Transferases/genética , Peptidil Transferases/metabolismo , Fenótipo
2.
Int J Syst Evol Microbiol ; 65(Pt 2): 570-577, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25404482

RESUMO

A thermophilic, agar-degrading bacterium, strain FAB2(T), was isolated from sewage sludge compost. According to phylogenetic analysis based on 16S rRNA gene sequences, strain FAB2(T) belonged to the family Paenibacillaceae within the phylum Firmicutes. However, FAB2(T) was different enough at the genus level from closely related species. The percentages of 16S rRNA gene sequence similarity with related organisms were 90.4 % for Thermobacillus xylanilyticus, 91.8 % for Paenibacillus barengoltzii, 89.4 % for Cohnella lupini, 90.1 % for Fontibacillus aquaticus, and 89.0 % for Saccharibacillus sacchari. Morphological and physiological analyses revealed that the strain was motile, rod-shaped, Gram-stain-positive, aerobic and able to form oval endospores in swollen sporangia. Ammonium was required as a nitrogen source while nitrate, nitrite, urea and glutamate were not utilized. Catalase and oxidase activities were weakly positive and positive, respectively. The bacterium grew in the temperature range of 50-65 °C and in media with pH 7.5 to 9.0. Optimal growth occurred at 60 °C and pH 8.0-8.6. Growth was inhibited at pH≤7.0 and NaCl concentrations ≥2.5 % (w/v). In chemotaxonomic characterization, MK-7 was identified as the dominant menaquinone. Major fatty acids were iso-C16 : 0 and C16 : 0. Dominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Phosphatidylcholine was present in a moderate amount. The diamino acid in the cell wall was meso-diaminopimelic acid. The G+C content of the genomic DNA was 49.5 mol% in a nucleic acid study. On the basis of genetic and phenotypic characteristics, strain FAB2(T) ( = NBRC 109510(T) = KCTC 33130(T)) showed characteristics suitable for classification as the type strain of a novel species of a new genus in the family Paenibacillaceae, for which the name Ammoniibacillus agariperforans gen. nov., sp. nov. is proposed.


Assuntos
Ágar/metabolismo , Bacillales/classificação , Filogenia , Microbiologia do Solo , Bacillales/genética , Bacillales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Bacilos Gram-Positivos/genética , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/isolamento & purificação , Japão , Dados de Sequência Molecular , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
3.
Artigo em Espanhol | LILACS | ID: lil-778006

RESUMO

La Actinomicosis Periapical es una lesión asociada con infecciones producidas por especies de Actinomyces y se ha considerado un factor en la perpetuación de las radiolucencias periapicales después de los tratamientos endodóncicos. El objetivo de esta revisión es dar a conocer la frecuencia de especies de Actinomices en la Actinomicosis Periapical...


Periapical Actinomycosis is a periapical lesion associated with infections caused by Actinomyces species and has been considered a contributing factor in the perpetuation of periapical radiolucencies after root canals. The objective of this review is to present frequency of Actinomyces species in Periapical Actinomycosis...


Assuntos
Humanos , Masculino , Feminino , Actinomicose/fisiopatologia , Bacilos Gram-Positivos/crescimento & desenvolvimento , Doenças da Polpa Dentária/diagnóstico , Doenças da Polpa Dentária/virologia , Infecções dos Tecidos Moles , Actinomyces , Bacteriologia , Cavidade Pulpar , Endodontia , Infectologia
4.
Food Microbiol ; 26(8): 876-81, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19835775

RESUMO

The abilities of five Lactobacillus sakei strains and one Lactococcus lactis strain to retain inhibitory activity against several target organisms in the flora of product during 12 weeks storage of vacuum-packaged lamb and beef was investigated. L. sakei strains were generally found capable of developing dominant populations on both beef and lamb. L. lactis 75 grew poorly on lamb did not inhibit co-inoculated Brochothrix thermosphacta. Lamb inoculated with the Sakacin-A producer L. sakei Lb706 had lower Listeria monocytogenes populations than lamb inoculated with a bacteriocin-negative variant. In beef packs inoculated with Clostridium estertheticum spores and L. sakei strain 27, 44 or 63, the development of blown-pack spoilage was delayed by up to one week. Campylobacter jejuni inoculated onto beef was recovered from fewer packs when it was co-inoculated with 3000 CFU cm(-2) of L. sakei strain 27, 44 or 63. Observed inhibition did not always correlate with inhibition observed in earlier media-based studies, supporting the view that functionality identified using simple media-based screening methods may not be replicated in the complex environment of stored foods, and vice-versa. These findings further define a set of L. sakei strains with potential for the extended bio-preservation of minimally processed fresh beef and lamb.


Assuntos
Antibiose , Bactérias/crescimento & desenvolvimento , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Lactobacillus/fisiologia , Lactococcus lactis/fisiologia , Carne/microbiologia , Animais , Fenômenos Fisiológicos Bacterianos , Campylobacter jejuni/crescimento & desenvolvimento , Bovinos , Clostridium/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Microbiologia de Alimentos , Bacilos Gram-Positivos/crescimento & desenvolvimento , Humanos , Listeria monocytogenes/crescimento & desenvolvimento , Ovinos , Especificidade da Espécie , Vácuo
5.
Rev. esp. quimioter ; 22(1): 25-29, mar. 2009. tab
Artigo em Espanhol | IBECS | ID: ibc-77644

RESUMO

Se ha determinado la actividad in vitro de fosfomicina,comparada con otros antimicrobianos de uso urinario, frentea aislamientos clínicos de Escherichia coli y Klebsiellapneumoniae de origen urinario productores de betalactamasasde espectro extendido (BLEE). Se estudió mediantedilución en agar o E-test la actividad de fosfomicina, cotrimoxazol,ciprofloxacino, nitrofurantoína, amoxicilina/clavulánicoy gentamicina frente a 71 cepas de E. coli y 13 deK. pneumoniae de origen urinario y productoras de BLEE. Lascepas de E. coli producían sobre todo BLEE de tipo CTX-M(76,1%), y principalmente CTX-M 14 (56,3%). Las cepas de K.pneumoniae produjeron casi exclusivamente enzimas tipoSHV (92,3 %), prevaleciendo SHV-2 (76,9 %). Gentamicina(4,4 %), fosfomicina (5,6 %) y nitrofurantoína (5,6%) mostraronlos menores porcentajes de resistencia en E. coli. Cotrimoxazoly ciprofloxacino (7,7%) mostraron los porcentajesde resistencia más bajos en K. pneumoniae (AU)


In vitro activity of fosfomycin, compared with otherantibiotics used for urinary tract infections (UTI), againstextended spectrum beta-lactamase (ESBL)-producing Escherichiacoli and Klebsiella pneumoniae clinical isolatesobtained from UTIs, was determined. The activity of fosfomycin,co-trimoxazole, ciprofloxacin, nitrofurantoin,amoxicillin/ clavulanic acid and gentamicin against 71ESBL-producing E. coli clinical isolates and 13 ESBLproducingK. pneumoniae clinical isolates obtained from UTI was studied by the agar-dilution method or E-test. E.coli isolates produced mainly CTX-M type ESBL (76.1%),especially CTX-M 14 (56.3 %). K. pneumoniae isolatesproduced most predominantly SHV-type ESBL (92.3%),mainly SHV-2 (76.9 %). Gentamicin (4.4 %), fosfomycin(5.6 %) and nitrofurantoin (5.6 %) showed the lowest resistanceproportions against E. coli. Co-trimoxazole andciprofloxacin (7.7 %) showed the lowest resistance proportionsagainst K. pneumoniae (AU)


Assuntos
Humanos , Masculino , Feminino , Escherichia coli , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/patogenicidade , Enterobacteriaceae , Enterobacteriaceae/patogenicidade , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/história , Infecções por Bactérias Gram-Negativas/fisiopatologia , Infecções por Bactérias Gram-Negativas/terapia , Fosfomicina/administração & dosagem , Fosfomicina/farmacologia , Fosfomicina/farmacocinética , Bacilos Gram-Positivos , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/patogenicidade
6.
Mikrobiologiia ; 76(5): 594-601, 2007.
Artigo em Russo | MEDLINE | ID: mdl-18069318

RESUMO

The rate of CO conversion by a pure culture of a thermophilic CO-oxidizing, H2-producing bacterium Carboxydocella sp. strain 1503 was determined by the radioisotopic method. The overall daily uptake of 14CO by the bacterium was estimated at 38-56 micromol CO per 1 ml of the culture. A radioisotopic method was developed to separate and quantitatively determine the products of anaerobic CO conversion by microbial communities in hot springs. The new method was first tested on the microbial community from a sample obtained from a hot spring in Kamchatka. The potential rate of CO conversion by the anaerobic microbial community was found to be 40.75 nmol CO/cm3 sediment per day. 85% of the utilized 14CO was oxidized to carbon dioxide; 14.5% was incorporated into dissolved organic matter, including 0.2% that went into volatile fatty acids; 0.5% was used for cell bio mass production; and only just over 0.001% was converted to methane.


Assuntos
Bactérias Anaeróbias/metabolismo , Técnicas Bacteriológicas/métodos , Monóxido de Carbono/metabolismo , Bacilos Gram-Positivos/metabolismo , Bactérias Anaeróbias/crescimento & desenvolvimento , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Bacilos Gram-Positivos/crescimento & desenvolvimento , Fontes Termais/microbiologia , Oxirredução , Contagem de Cintilação
7.
Syst Appl Microbiol ; 30(1): 16-26, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17196483

RESUMO

Two anaerobic bacteria involved in the conversion of the plant lignan secoisolariciresinol diglucoside were isolated from faeces of a healthy male adult. The first isolate, strain SDG-Mt85-3Db, was a mesophilic strictly anaerobic Gram-positive helically coiled rod. Based on 16S r RNA gene sequence analysis, its nearest relatives were Clostridium cocleatum (96.7% similarity) and Clostridium ramosum (96.6%). In contrast to these species, the isolate was devoid of alpha-galactosidase and -glucosidase and did not grow on maltose, melibiose, raffinose, rhamnose and trehalose. The hypothesis that strain SDG-Mt85-3Db represents a new bacterial species of the Clostridium cluster XVIII was confirmed by DNA-DNA hybridisation experiments. The G+C content of DNA of strain SDG-Mt85-3Db (30.7+/-0.8 mol%) was comparable with that of Clostridium butyricum, the type species of the genus Clostridium. The name Clostridium saccharogumia is proposed for strain SDG-Mt85-3Db (=DSM 17460T=CCUG 51486T). The second isolate, strain ED-Mt61/PYG-s6, was a mesophilic strictly anaerobic Gram-positive regular rod. Based on 16S rRNA gene sequence analysis, its nearest relatives were Clostridium amygdalinum (93.3%), Clostridium saccharolyticum (93.1%) and Ruminococcus productus (93.0%). The isolate differed from these species in its ability to dehydrogenate enterodiol. It also possessed alpha-arabinosidase and -galactosidase and had a higher G+C content of DNA (48.0 mol%). According to these findings, it is proposed to create a novel genus, Lactonifactor, and a novel species, Lactonifactor longoviformis, to accommodate strain ED-Mt61/PYG-s6. The type strain is DSM 17459T (=CCUG 51487T).


Assuntos
Butileno Glicóis/metabolismo , Clostridium/classificação , Carboidratos da Dieta/metabolismo , Fezes/microbiologia , Glucosídeos/metabolismo , Bacilos Gram-Positivos/classificação , Fitoestrógenos/metabolismo , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Adulto , Composição de Bases , Clostridium/genética , Clostridium/crescimento & desenvolvimento , Clostridium/metabolismo , Colo/microbiologia , Meios de Cultura , DNA/química , DNA Ribossômico/genética , Genótipo , Bacilos Gram-Positivos/genética , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/metabolismo , Humanos , Lignanas/metabolismo , Masculino , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Fenótipo , Filogenia , RNA Ribossômico 16S/genética
8.
Food Microbiol ; 23(8): 785-90, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16943083

RESUMO

The effect of a bacteriocinogenic Brochothrix campestris ATCC 43754 upon the growth of Brochothrix thermosphacta and a 4 strain mixture of Listeria monocytogenes was determined in All Purpose Tween (APT) broth and on pork adipose tissue discs at 4 degrees C. Inocula were prepared to give initial numbers of B. campestris of 6-7 log cfu/ml or cm(2) and 3-4 log cfu/ml or cm(2) of B. thermosphacta and L. monocytogenes. Adipose tissue discs were evaluated by a sensory panel to determine the intensity and acceptability of any off-odours produced during the growth of B. campestris. During co-culture in APT broth with B. campestris the growth of B. thermosphacta or L. monocytogenes was 4 log cycles less than growth in its absence. B. campestris showed limited growth on inoculated pork adipose tissue, increasing from initial numbers of about 6 log cfu/cm(2) to a maximum of 7 log cfu/cm(2) within 7d. B. campestris at numbers of 7 log cfu/cm(2) produced slight off-odours but these were not perceived by the panel as unacceptable. When co-inoculated on adipose tissue discs with B. campestris the numbers of B. thermosphacta or L. monocytogenes was limited to about 2-3 log units less than the numbers attained in its absence. B. campestris ATCC 43754 may be useful for meat preservation because it can inhibit B. thermosphacta and L. monocytogenes in situ while producing little change in the sensory properties of the product.


Assuntos
Antibiose , Bacteriocinas/biossíntese , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/fisiologia , Listeria monocytogenes/crescimento & desenvolvimento , Carne/microbiologia , Tecido Adiposo/microbiologia , Animais , Antibacterianos , Técnicas de Cocultura , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Humanos , Carne/normas , Odorantes/análise , Suínos , Paladar , Temperatura , Fatores de Tempo
9.
Food Microbiol ; 23(8): 797-802, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16943085

RESUMO

The microbial flora of fresh meat stored aerobically at 5 degrees C up to spoilage was enumerated and collected in order to have mixed spoilage bacterial groups to be used in competition tests against Brochothrix thermosphacta. The bacterial groups collected as bulk colonies were identified by PCR-DGGE followed by partial 16S rDNA sequencing. The predominant bacteria associated with the spoilage of the refrigerated beef were B. thermosphacta, Pseudomonas spp, Enterobacteriaceae and lactic acid bacteria (LAB). The interactions between B. thermosphacta and the other spoilage microbial groups were studied in vitro at 5 degrees C. The results showed that a decrease of the growth of B. thermosphacta was evidenced in presence of LAB at 5 degrees C while the bacterium is the dominant organism when inoculated with mixtures of Pseudomonas spp., LAB and Enterobacteriaceae. A better understanding of bacterial meat spoilage interactions may lead to improved quality of fresh meat stored in refrigerated conditions.


Assuntos
DNA Bacteriano/análise , Conservação de Alimentos/métodos , Bacilos Gram-Positivos/crescimento & desenvolvimento , Lactobacillus/fisiologia , Carne/microbiologia , Antibiose , Contagem de Colônia Microbiana , DNA Ribossômico/análise , Eletroforese em Gel de Ágar/métodos , Microbiologia de Alimentos , Bacilos Gram-Positivos/classificação , Bacilos Gram-Positivos/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Fatores de Tempo
10.
Lett Appl Microbiol ; 43(2): 194-9, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16869904

RESUMO

AIMS: To evaluate the inhibition effectiveness of Lactobacillus curvatus CRL705 used as a bioprotective culture and of its bacteriocins, lactocin 705 and lactocin AL705, against Listeria innocua, Brochothrix thermosphacta and indigenous lactic acid bacteria (LAB) in vacuum-packaged meat stored at 2 degrees C. METHODS AND RESULTS: The live culture of Lact. curvatus CRL705 as well as synthetic lactocin 705 and purified lactocin AL705 were shown to be similarly effective in preventing the growth of B. thermosphacta and L. innocua in meat discs in contrast to control samples in which these micro-organisms grew rapidly, their numbers increasing by 3.0- and 2.1-log cycles respectively. In addition, indigenous LAB population showed a lower growth rate in the presence of lactocin 705. Bacteriocin activity was detected in the meat discs during 36 days at 2 degrees C irrespective of the biopreservation strategy applied. Changes in pH were not significantly different in meat discs treated with the protective culture when compared with control samples. CONCLUSIONS: Lactobacillus curvatus CRL705 and the produced bacteriocins, lactocin 705 and lactocin AL 705, were effective in inhibiting L. innocua and B. thermosphacta. The use of the bioprotective culture in refrigerated vacuum-packaged fresh meat would be more feasible from an economic and legal point of view. SIGNIFICANCE AND IMPACT OF THE STUDY: Establishment of biopreservation as a method to ensure the microbiological safety of vacuum-packaged fresh meat at 2 degrees C.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Conservação de Alimentos/métodos , Bacilos Gram-Positivos/efeitos dos fármacos , Lactobacillus/química , Listeria/efeitos dos fármacos , Carne/microbiologia , Microbiologia de Alimentos , Embalagem de Alimentos/métodos , Conservação de Alimentos/economia , Conservação de Alimentos/legislação & jurisprudência , Bacilos Gram-Positivos/crescimento & desenvolvimento , Listeria/crescimento & desenvolvimento
11.
Int J Food Microbiol ; 95(2): 169-75, 2004 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-15282129

RESUMO

The possibility was examined of developing a predictive model that combined microbial growth (increase in cellular number) and extracellular enzyme activity of a cocktail of three strains of Brochothrix thermosphacta. Estimations of growth and enzyme activity were made within a three-dimensional matrix of conditions: temperature 2-20 degrees C, pH value 4.0-7.5 and water activity (a(w)) 0.95-0.995. A model which predicted growth based on increases in cell number was constructed. No extracellular lipases were detected, but slight proteolytic reactions were observed. Although it was not possible to model protease activity, the growth model and information relating to enzyme activity will be made freely available in a database on the Internet.


Assuntos
Endopeptidases/metabolismo , Microbiologia de Alimentos , Conservação de Alimentos , Bacilos Gram-Positivos/enzimologia , Bacilos Gram-Positivos/crescimento & desenvolvimento , Modelos Biológicos , Contagem de Colônia Microbiana , Meios de Cultura , Contaminação de Alimentos/análise , Concentração de Íons de Hidrogênio , Valor Preditivo dos Testes , Cloreto de Sódio/farmacologia , Temperatura , Água/metabolismo
12.
Appl Environ Microbiol ; 69(10): 6321-6, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14532100

RESUMO

Formate stimulates growth of a new bacterium from human feces. With high formate, it ferments glucose to acetate via the Wood-Ljungdahl pathway. The original isolate fermented vegetable cellulose and carboxymethylcellulose, but it lost this ability after storage at -76 degrees C. 16S rRNA gene sequencing identifies it as a distinct line within the Clostridium coccoides supra-generic rRNA grouping. We propose naming it Bryantella formatexigens gen. nov., sp. nov.


Assuntos
Acetatos/metabolismo , Fezes/microbiologia , Formiatos/metabolismo , Bacilos Gram-Positivos/classificação , Bacilos Gram-Positivos/crescimento & desenvolvimento , Meios de Cultura , DNA Bacteriano/análise , DNA Ribossômico/análise , Fermentação , Bacilos Gram-Positivos/genética , Humanos , Dados de Sequência Molecular , RNA Ribossômico 16S , Análise de Sequência de DNA
13.
Mikrobiologiia ; 72(2): 161-7, 2003.
Artigo em Russo | MEDLINE | ID: mdl-12751237

RESUMO

Growth physiology of the iron-reducing bacteria Thermoterrabacterium ferrireducens and Thermoanaerobacter siderophilus was investigated. The stimulation of the organotrophic growth of T. ferrireducens and T. siderophilus in the presence of Fe(III) was shown to be due to the utilization of ferric iron as an electron acceptor in catabolic processes and not to the effect exerted on the metabolism by Fe(II) or by changes in the redox potential. It was established that Fe(III) reduction in T. ferrireducens is not a detoxication strategy. In T. siderophilus, this process is carried out to relieve the inihibitory effect of hydrogen. T. ferrireducens was shown to be capable of lithoautotrophic growth with molecular hydrogen as electron donor and amorphous ferric oxide as electron acceptor, in the absence of any organic substances. The minimum threshold of H2 consumption was 3 x 10(-5) vol % of H2. The presence of CO dehydrogenase activity in T. ferrireducens suggests that CO2 fixation in this organism involves the anaerobic acetyl-CoA pathway. T. siderophilus failed to grow under lithoautotrophic conditions. The fact that T. ferrireducens contains c-type cytochromes and T. sidrophilus lacks them confirms the operation of different mechanisms of ferric iron reduction in these species.


Assuntos
Bactérias Anaeróbias/crescimento & desenvolvimento , Bactérias Anaeróbias/metabolismo , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/metabolismo , Ferro/metabolismo , Bactérias Anaeróbias/química , Meios de Cultura , Grupo dos Citocromos c , Compostos Férricos , Compostos Ferrosos , Bacilos Gram-Positivos/química , Hidrogênio/metabolismo , Especificidade da Espécie
14.
Vasa ; 32(1): 31-5, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12677763

RESUMO

The incidence of infection following arterial reconstruction using synthetic graft materials varies from less than 1 to 5%. One of three mechanisms is thought to be responsible: 1. intraoperative contamination, 2. extension from adjacent infected or colonized tissue, or 3. hematogenous or lymphogenous seeding. We present ultrastructural data of a patient with a polymicrobial graft infection due to a prostheto-enteric fistula 16 years after reconstruction of an aortobifemoral graft. The polymer surface showed signs of biodegradation and was completely covered with a layer of plasma proteins. Disrupted fibroblasts on the intersegmental graft surface were surrounded by bundles of collagen. Gram-negative rods and grampositive cocci were embedded in an extracellular EPS matrix. Bacterial culture confirmed growth of Eikenella corrodens, Fusobacterium nucleatum and Peptostreptococcus species. Fibrin and granulation tissue from the neoadventitia started to mark off the inflammatory process. Transmission electron microscopy is a valuable tool for the investigation of alloplastic arterial devices. After 16 years of implantation the graft shows different signs of biodegradation.


Assuntos
Biofilmes/crescimento & desenvolvimento , Prótese Vascular , Materiais Revestidos Biocompatíveis , Colágeno , Isquemia/cirurgia , Perna (Membro)/irrigação sanguínea , Síndrome de Leriche/cirurgia , Poliésteres , Infecções Relacionadas à Prótese/patologia , Aorta Abdominal/cirurgia , Doenças da Aorta/microbiologia , Técnicas Bacteriológicas , Colágeno/ultraestrutura , Fibrina/ultraestrutura , Cocos Gram-Positivos/crescimento & desenvolvimento , Cocos Gram-Positivos/ultraestrutura , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/ultraestrutura , Tecido de Granulação/patologia , Humanos , Fístula Intestinal/microbiologia , Fístula Intestinal/patologia , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Complicações Pós-Operatórias/microbiologia , Complicações Pós-Operatórias/patologia , Infecções Relacionadas à Prótese/microbiologia
15.
Trends Microbiol ; 10(10): 452-5, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12377554

RESUMO

Generally speaking, bacteria grow and divide indefinitely, and as long as the growth conditions are maintained they retain constant dimensions and shapes with little variation. How they do this is a question that I have been considering for three decades. Here, I discuss two hypothetical mechanisms, one for Gram-positive rods and the other for Gram-negative rods. These mechanisms are consistent with what is known, but make some unproven assumptions.


Assuntos
Bacilos e Cocos Aeróbios Gram-Negativos/química , Bacilos Gram-Positivos/química , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Bacilos e Cocos Aeróbios Gram-Negativos/crescimento & desenvolvimento , Bacilos e Cocos Aeróbios Gram-Negativos/ultraestrutura , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/ultraestrutura , Modelos Biológicos , Modelos Moleculares
16.
Crit Rev Microbiol ; 28(1): 61-77, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-12003041

RESUMO

For free-living single-celled organisms, it can be assumed that it is their success in acquiring resources and converting them into cytoplasm that controls the timing of their cell cycles. Cytoplasm is the sink for the bulk of the environmental resources. It must be the case that this type of control must operate in dilute cultures under adequate nutrition in a constant environment. It follows that there ought to be mechanisms that measure or count the cell's biomass or some component of the cytoplasm to measure their growth success. Besides sensing their biomass, they need to know when a certain value of the cell size has been achieved. When this critical state has been achieved, the cell needs to have an all-or-none trigger that either initiates chromosome replication, the completion of cell replication, cell division, or the process of separating sister cells physiologically or physically. Any of these four different stages, in principle, may be the one triggered in response to cell growth in different species of microorganisms. Alternatively, multiple triggers at different cell sizes may be activated at different cell cycle stages. Although initiation of chromosome replication has been believed to be the event triggered in Escherichia coli, this probably is not generally the case and other control mechanisms may act in other prokaryotes. How the increase in cell biomass is self-assessed and used to carry out critical cell cycle events is not understood in any case. This deficiency in our knowledge of microbial cell physiology is grave. The factor that probably has prevented the elucidation of the mechanisms in any organism is that enzymatic processes deal with concentrations, and a cell cycle trigger must respond to the total amount of material present in a cell. This article discusses the theoretically possible classes of mechanisms for the cell to respond when it has achieved its appropriate critical size. These breakdown into three groups: those mechanisms that assess the total amount of biomass or some special subcellular component, and those that measure the ratio of one component to another component where their two syntheses are differently controlled by cell physiology and morphology, and a third group with some specialized mechanisms.


Assuntos
Bactérias/citologia , Bactérias/crescimento & desenvolvimento , Ciclo Celular/fisiologia , Citoplasma/microbiologia , Regulação Alostérica , Indução Enzimática , Repressão Enzimática , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bacilos Gram-Positivos/crescimento & desenvolvimento , Modelos Biológicos , Fosfoproteínas/biossíntese , Plasmídeos , Staphylococcus/citologia , Streptococcus/citologia
17.
J Endod ; 27(2): 76-81, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11491642

RESUMO

Two sets of teeth with apical periodontitis were collected at different geographic locations to study the identity of bacteria left in the root dentinal tubules. Root dentin of 20 of these teeth was cultured from three locations between pulp and cementum (A, B, and C). In addition dentin from eight teeth was examined histologically. Using the culturing technique bacteria were found in 77% of the dentin samples from set 1 (Amsterdam) and in 87.5% of the dentin samples from set 2 (Glasgow). At greater distance, in layer C, from the pulp bacteria were found in 62% (13 of 21) of the dentin samples. Twenty-three percent (3 of 13) of set 1 and 25% (2 of 8) of set 2 contained >50,000 colony-forming units/mg of dentin in layer C. In layers closer to the pulp higher numbers of anaerobic bacteria and gram-positive rods were found, as well as a larger number of bacterial species. Histological sections showed bacterial penetration in dentinal tubules in 5 of 8 teeth. In the other three teeth where the colony-forming units/mg recovered was <10,000, no histological signs of tubule penetration was seen. It seems clear that, in more than half of the infected roots, bacteria are present in the deep dentin close to the cementum and that anaerobic culturing of dentin is more sensitive than histology to detect these bacteria.


Assuntos
Bactérias/classificação , Dentina/microbiologia , Periodontite Periapical/microbiologia , Raiz Dentária/microbiologia , Actinomyces/crescimento & desenvolvimento , Bactérias/crescimento & desenvolvimento , Bactérias Anaeróbias/crescimento & desenvolvimento , Técnicas Bacteriológicas , Bacteroides/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Meios de Cultura , Cemento Dentário/microbiologia , Polpa Dentária/microbiologia , Dentina/ultraestrutura , Fusobacterium/crescimento & desenvolvimento , Bactérias Gram-Negativas/crescimento & desenvolvimento , Cocos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/crescimento & desenvolvimento , Humanos , Países Baixos , Peptostreptococcus/crescimento & desenvolvimento , Porphyromonas/crescimento & desenvolvimento , Prevotella/crescimento & desenvolvimento , Escócia , Estatísticas não Paramétricas , Raiz Dentária/ultraestrutura
18.
J Bacteriol ; 183(11): 3276-81, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11344134

RESUMO

The Moorella thermoacetica aromatic O-demethylase was characterized as an inducible three-component system with similarity to the methanogenic methanol, methylamine, and methanethiol methyltransferases and to the O-demethylase system from Acetobacterium dehalogenans. MtvB catalyzes methyl transfer from a phenylmethylether to the cobalt center of MtvC, a corrinoid protein. MtvA catalyzes transmethylation from MtvC to tetrahydrofolate, forming methyltetrahydrofolate. Cobalamin can substitute for MtvC.


Assuntos
Clostridium/enzimologia , Oxirredutases O-Desmetilantes/genética , Oxirredutases O-Desmetilantes/isolamento & purificação , Ácido Vanílico/metabolismo , Vitamina B 12/análogos & derivados , Sequência de Aminoácidos , Anaerobiose , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clostridium/crescimento & desenvolvimento , Dicamba/metabolismo , Bacilos Gram-Positivos/enzimologia , Bacilos Gram-Positivos/crescimento & desenvolvimento , Hidroxocobalamina/metabolismo , Cinética , Metilação , Metiltransferases/metabolismo , Dados de Sequência Molecular , Oxirredutases O-Desmetilantes/química , Oxirredutases O-Desmetilantes/metabolismo , Tetra-Hidrofolatos/metabolismo , Vitamina B 12/metabolismo
19.
Int J Syst Evol Microbiol ; 51(Pt 1): 141-149, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11211251

RESUMO

A new anaerobic, thermophilic, CO-utilizing marine bacterium, strain JMT, was isolated from a submarine hot vent in Okinawa Trough. Cells of strain JMT were non-motile thin straight rods, sometimes branching, with a cell wall of the Gram-positive type, surrounded with an S-layer. Chains of three to five cells were often observed. The isolate grew chemolithotrophically on CO, producing equimolar quantities of H2 and CO2 (according to the equation CO+H2O-->CO2+H2) and organotrophically on peptone, yeast extract, starch, cellobiose, glucose, galactose, fructose and pyruvate, producing H2, acetate and CO2. Growth was observed from 50 to 80 degrees C with an optimum at 70 degrees C. The optimum pH was 6.8-7.1. The optimum concentration of sea salts in the medium was 20.5-25.5 g l(-1). The generation time under optimal conditions was 7.1 h. The DNA G+C content was 33 mol %. Growth of isolate JMT was not inhibited by penicillin, but ampicillin, streptomycin, kanamycin and neomycin completely inhibited growth. The results of 16S rDNA sequence analysis revealed that strain JMT belongs to the Thermoanaerobacter phylogenetic group within the Bacillus-Clostridium subphylum of Gram-positive bacteria but represents a separate branch of this group. On the basis of morphological and physiological features and phylogenetic data, this isolate should be assigned to a new genus, for which the name Carboxydobrachium is proposed. The type species is Carboxydobrachium pacificum; the type strain is JMT (= DSM 12653T).


Assuntos
Bactérias Anaeróbias/classificação , Monóxido de Carbono/metabolismo , Bacilos Gram-Positivos/classificação , Temperatura Alta , Água do Mar/microbiologia , Bactérias Anaeróbias/genética , Bactérias Anaeróbias/crescimento & desenvolvimento , Bactérias Anaeróbias/metabolismo , Técnicas de Tipagem Bacteriana , Composição de Bases , Meios de Cultura , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Genes de RNAr , Bacilos Gram-Positivos/genética , Bacilos Gram-Positivos/crescimento & desenvolvimento , Bacilos Gram-Positivos/metabolismo , Japão , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
20.
Appl Environ Microbiol ; 67(1): 300-6, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11133459

RESUMO

The demethylation of the algal osmolyte dimethylsulfoniopropionate (DMSP) to methylthiopropionate (MTPA) by (homo)acetogenic bacteria was studied. Five Eubacterium limosum strains (including the type strain), Sporomusa ovata DSM 2662(T), Sporomusa sphaeroides DSM 2875(T), and Acetobacterium woodii DSM 1030(T) were shown to demethylate DMSP stoichiometrically to MTPA. The (homo)acetogenic fermentation based on this demethylation did not result in any significant increase in biomass. The analogous demethylation of glycine betaine to dimethylglycine does support growth of acetogens. In batch cultures of E. limosum PM31 DMSP and glycine betaine were demethylated simultaneously. In mixed substrates experiments with fructose-DMSP or methanol-DMSP, DMSP was used rapidly but only after exhaustion of the fructose or the methanol. In steady-state fructose-limited chemostat cultures (at a dilution rate of 0.03 h(-1)) with DMSP as a second reservoir substrate, DMSP was biotransformed to MTPA but this did not result in higher biomass values than in cultures without DMSP; cells from such cultures demethylated DMSP at rates of approximately 50 nmol min(-1) mg of protein(-1), both after growth in the presence of DMSP and after growth in its absence. In cell extracts of glycine betaine-grown strain PM31, DMSP demethylation activities of 21 to 24 nmol min(-1) mg of protein(-1) were detected with tetrahydrofolate as a methyl acceptor; the activities seen with glycine betaine were approximately 10-fold lower. A speculative explanation for the demethylation of DMSP without an obvious benefit for the organism is that the DMSP-demethylating activity is catalyzed by the glycine betaine-demethylating enzyme and that a transport-related factor, in particular a higher energy demand for DMSP transport across the cytoplasmic membrane than for glycine betaine transport, may reduce the overall ATP yield of the fermentation to virtually zero.


Assuntos
Acetilcoenzima A/biossíntese , Eubacterium/metabolismo , Bacilos Gram-Positivos/metabolismo , Sarcosina/análogos & derivados , Compostos de Sulfônio/metabolismo , Betaína/metabolismo , Meios de Cultura , Eubacterium/crescimento & desenvolvimento , Genes de RNAr , Bacilos Gram-Positivos/crescimento & desenvolvimento , Metilação , Dados de Sequência Molecular , Filogenia , Propionatos/metabolismo , RNA Ribossômico 16S/genética , Sarcosina/metabolismo , Análise de Sequência de DNA
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