RESUMO
When ethanol is added to the growth medium of Clostridium thermocellum ATCC 27405 and C9, a different membrane composition is observed after the period of growth arrest. Changes in fatty acid composition and some unsaturated, branched hydrocarbons have been monitored by GLC-MS. There is a marked increase in normal and anteiso-branched fatty acids at the expense of isobranched fatty acids and an increase in short and unsaturated fatty acids. Thus, an adaptive response to growth in the presence of ethanol induces a membrane containing fatty acids with lower melting points and produces a more 'fluid' membrane. The suggestion is made that these membrane changes may be maladaptive to the performance of C. thermocellum.
Assuntos
Clostridium/metabolismo , Etanol/farmacologia , Lipídeos de Membrana/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Clostridium/efeitos dos fármacos , Ácidos Graxos/análise , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Lipídeos de Membrana/isolamento & purificaçãoRESUMO
UNLABELLED: Epicondylitis is common in young patients and athletes. It is usually addressed with uneffective or very aggressive treatments. Due to the recurrence of the condition and the disability it causes its management is very demanding. METHODS: Five patients ages 30-45 years with diagnosis of epicondylitis were treated and followed-up. An outpatient procedure was performed under general anesthesia consisting of percutaneous release of the annular ligament and injection of 5cc of platelet rich plasma from the patient following the centrifugation of a blood sample. Following the injection the patient was referred to physical therapy and rehabilitation with a specific program consisting of isotonic exercises aimed at muscle strengthening. RESULTS: At the two-week follow-up, important subsidence of symptoms was reported, with full ranges of motion, intact muscle strength, and full resumption of daily life and sports activities. CONCLUSIONS: This alternative method is a good and not very invasive option for patients with epicondylitis, and it may help avoid surgical treatment. An appropriate rehabilitation program contributes to optimize the results and helps patients return sooner to their activities of daily living.
Assuntos
Plasma Rico em Plaquetas , Cotovelo de Tenista/terapia , Adulto , Humanos , Pessoa de Meia-Idade , Procedimentos Ortopédicos/métodos , Cotovelo de Tenista/cirurgiaAssuntos
Morfolinas/metabolismo , Mutagênicos , Compostos Nitrosos/metabolismo , Pirrolidinas/metabolismo , Salmonella typhimurium/efeitos dos fármacos , Alquilação , Animais , Sequência de Bases , Fígado/metabolismo , Morfolinas/farmacologia , Mutação , Compostos Nitrosos/farmacologia , Pirrolidinas/farmacologia , Ratos , Extratos de TecidosRESUMO
Spores of Clostridium perfringens, type A, were given separate or sequential treatments of gamma radiation (0 to 0.7 Mrad) and/or high temperature (93 to 103 degrees C). Prior heating, sufficient to inactivate 40 to 99% of the viable spores, had no effect on the subsequent radiation inactivation rate. Prior irradiation had a sensitizing effect on subsequently heated spores. The degree of sensitization to heat, as measured by thermal inactivation rate, increased with increased radiation pretreatment dose.
Assuntos
Clostridium perfringens/efeitos da radiação , Radioisótopos de Cobalto , Temperatura Alta , Clostridium perfringens/fisiologia , Raios gama , Esporos Bacterianos/fisiologia , Esporos Bacterianos/efeitos da radiaçãoRESUMO
Minimal medium recovery of heat-treated Salmonella typhimurium LT-2 has been expressed as the reduced viability on trypticase soy agar supplemented with 0.5% yeast extract (TSY) relative to a glucose-salts (M-9) agar. Incubation of S. typhimurium LT-2 in water at 50 C for 15 min did not change the sedimentation patterns of deoxyribonucleic acid (DNA) in alkaline sucrose gradients. The same pattern was obtained if the heated cells were further incubated for 15 min at 37 C in M-9 broth. However, a marked increase in DNA single-strand breakage accompanied by a loss of viability was observed after a similar incubation of heated bacteria in TSY broth. If heated bacteria were incubated in M-9 broth before TSY broth, there was a decrease in the single-strand breakage occurring in the TSY broth. This decrease is believed to be the result of repair of heat-induced damage. We conclude that minimal medium recovery after heat treatment is due to DNA damage caused by sequential exposure to heat and TSY medium, such damage not occurring after sequential exposure to heat and M-9 medium.
Assuntos
Meios de Cultura , DNA Bacteriano/metabolismo , Temperatura Alta , Salmonella typhimurium/metabolismo , Isótopos de Carbono , Sobrevivência Celular , Centrifugação com Gradiente de Concentração , DNA Bacteriano/análise , DNA de Cadeia Simples/análise , Peso Molecular , Desnaturação de Ácido Nucleico , Salmonella typhimurium/análise , Salmonella typhimurium/crescimento & desenvolvimento , Esferoplastos/análise , Timidina/metabolismo , TrítioRESUMO
The effect of presence or absence of air on minimal medium recovery of heated Salmonella typhimurium was investigated. It was determined that the expression of minimal medium recovery is not only dependent on heat and a nutritionally complex medium but also on air. Unlike in the presence of air, in the presence of nitrogen, cells were able to recover their ability to grow on Trypticase soy agar enriched with 0.5% yeast extract (TSY) when incubated in TSY broth. It was established that in the presence of nitrogen the number of heat-TSY- induced, single-straneded breaks in deoxyribonucleic acid (DNA) were less than in the presence of air. Furthermore, the DNA breaks in nitrogen were repaired, whereas DNA breaks in air were not. The ability of cells to grow on TSY agar corresponded well with their ability to repair damage to DNA.
Assuntos
Ar , Meios de Cultura , Reparo do DNA , Salmonella typhimurium/metabolismo , Ágar , Anaerobiose , Contagem de Células , Centrifugação com Gradiente de Concentração , DNA Bacteriano/análise , DNA Bacteriano/biossíntese , Temperatura Alta , Peso Molecular , Nitrogênio , Salmonella typhimurium/crescimento & desenvolvimentoRESUMO
The growth of Clostridium thermocellum ATCC 27405 and of C9, an ethanol-resistant mutant of this strain, at different ethanol concentrations and temperatures was characterized. After ethanol addition, cultures continued to grow for 1 to 2 h at rates similar to those observed before ethanol was added and then entered a period of growth arrest, the duration of which was a function of the age of inocula. After this period, cultures grew at an exponential rate that was a function of ethanol concentration. The wild-type strain showed a higher energy of activation for growth than the ethanol-tolerant derivative. The optimum growth temperature of the wild type decreased as the concentration of the ethanol challenge increased, whereas the optimum growth temperature for C9 remained constant. The results are discussed in terms of what is known about the effects of ethanol and temperature on membrane composition and fluidity.
Assuntos
Clostridium/efeitos dos fármacos , Etanol/farmacologia , Clostridium/genética , Clostridium/crescimento & desenvolvimento , Tolerância a Medicamentos , Mutação , TemperaturaRESUMO
The effects of the centrifugal field on the sedimentation coefficient of the heated (50 degrees C, 30 min) Escherichia coli nucleoid were investigated. Form 3,000 r.p.m. the sedimentation coefficients of the heated nucleoids were highly dependent on rotor speed. At 3,000 r.p.m. thier sedimentation coefficient was about 4,000 S while at 7,000 r.p.m. if was about 1,500-1,700 S. At 7,000 r.p.m. and over, nucleoid aggregations occurred and it was difficult to differentiate speed dependence from nucleoid aggregation. Factors likely to cause speed dependence and/or nucleoid aggregation are indicated. The practical importance of these findings is pointed out.
Assuntos
Cromossomos Bacterianos/análise , Escherichia coli/ultraestrutura , Proteínas de Bactérias , Centrifugação com Gradiente de Concentração , DNA Bacteriano , Temperatura Alta , Conformação de Ácido Nucleico , Conformação ProteicaRESUMO
The folded chromosome or nucleoid of Escherichia coli was analyzed by low-speed sedimentation in neutral sucrose gradients after heat treatment (30 min at 50 degrees C) and subsequent incubation of cells at 37 degrees C for various times. Heat treatment resulted in in vivo association of the nucleoids with cellular protein and in an increase in sedimentation coefficient. During incubation at 37 degrees C, a fraction of the nucleoids, from heated cells, because dissociated from cellular protein and regained their characteristic sedimentation coefficients. The percentage of nucleoids which returned to their control sedimentation position in the sucrose gradients corresponded to the percentage of cells able to repair thermal damage as assayed by enumeration on agar plates.
Assuntos
Cromossomos Bacterianos/fisiologia , Escherichia coli/ultraestrutura , Proteínas de Bactérias/análise , Centrifugação com Gradiente de Concentração , Cromossomos Bacterianos/análise , Escherichia coli/fisiologia , Temperatura AltaRESUMO
Spontaneous and UV irradiation-induced auxotrophic mutants of Clostridium thermocellum, an anaerobic cellulolytic thermophile, were isolated after penicillin enrichment in a chemically defined medium.
RESUMO
The folded chromosome or nucleoid of Escherichia coli was analyzed by low-speed sedimentation in neutral sucrose gradients after in vivo heat treatment. Heat treatment of cultures at 50 degree C for 15, 30, and 60 min resulted in in vivo association of the nucleoids with cellular protein. Structural changes, determined by the increase in speed dependence of the nucleoids from heated cells, also occurred. These changes were most likely due to the unfolding of the typical compact nucleoid structure. The nucleoids from heated cells also had notably higher sedimentation coefficients (3,000 to 4,500S) than nucleoids from control cells (1,800S). These nucleoids did not contain greater than normal amounts of membrane phospholipids or ribonucleic acid. We propose that the protein associated with the nucleoids from heated cells causes the observed sedimentation coefficient increases.
Assuntos
Cromossomos/ultraestrutura , Escherichia coli/análise , Temperatura Alta/efeitos adversos , Proteínas de Bactérias/análise , Membrana Celular , Centrifugação com Gradiente de Concentração , DNA Bacteriano/análise , Desoxirribonucleases , Desoxirribonucleoproteínas/análise , Fosfolipídeos/análise , RNA Bacteriano/análiseRESUMO
The effect of solute concentration on the sensitization of Clostridium perfringens spores to heat by ionizing radiation was investigated. As we have shown previously, spores of C. perfringens treated with gamma radiation are now sensitive to subsequent heat treatments than are spores that receive no radiation treatment. When gamma-irradiated spores were heated in the presence of increasing concentrations of glycerol or sucrose, the heat sensitivity induced by irradiation was progressively decreased. The magnitude of the increase in heat resistance induced by extracellular solutes was greater in gamma-irradiated spores than in nonirradiated spores. Based on these observations, it is proposed that the induction of heat sensitivity in spores by radiation is related to the loss of osmoregulatory or dehydrating mechanisms in irradiated spores.
Assuntos
Clostridium perfringens/efeitos da radiação , Glicerol/farmacologia , Temperatura Alta , Sacarose/farmacologia , Clostridium perfringens/efeitos dos fármacos , Clostridium perfringens/fisiologia , Raios gama , Pressão Osmótica , Soluções , Esporos BacterianosRESUMO
The extremely gentle lysis and unfolding procedures that have been developed for the isolation of nucleoid deoxyribonucleic acid (DNA; K. M. Ulmer et al., J. Bacteriol. 138:475-485, 1979) yield undamaged, replicating genomes, thus permitting direct measurement of the formation and repair of DNA double-strand breaks at biologically significant doses of ionizing radiation. Repair of ionizing radiation damage to folded chromosomes of Escherichia coli K-12 strain AB2497 was observed within 2 to 3 h of post-irradiation incubation in growth medium. Such behavior was not observed after post-irradiation incubation in growth medium of a recA13 strain (strain AB2487). A model based on recombinational repair is proposed to explain the formation of 2,200 to 2,300S material during early stages of incubation and to explain subsequent changes in the gradient profiles. Association of unrepaired DNA with the plasma membrane is proposed to explain the formation of a peak of rapidly sedimenting material (greater than 3,100S) during the later stages of repair. Direct evidence of repair of double-strand breaks during post-irradiation incubation in growth medium was obtained from gradient profiles of DNA from ribonuclease-digested chromosomes. The sedimentation coefficient of broken molecules was restored to the value of unirradiated DNA after 2 to 3 h of incubation, and the fraction of the DNA repaired in this fashion was equal to the fraction of cells that survived at the same dose. An average of 2.7 double-strand breaks per genome per lethal event was observed, suggesting that one to two double-strand breaks per genome are repairable in E. coli K-12 strain AB2497.
Assuntos
Cromossomos Bacterianos/metabolismo , Reparo do DNA , DNA Bacteriano/biossíntese , Escherichia coli/metabolismo , Núcleo Celular/efeitos da radiação , Cromossomos Bacterianos/efeitos da radiação , Radioisótopos de Cobalto , DNA Bacteriano/efeitos da radiação , Escherichia coli/efeitos da radiação , Ribonucleases/metabolismoRESUMO
The structures of the membrane-free nucleoid of Escherichia coli K-12 and of unfolded chromosomal deoxyribonucleic acid (DNA) were investigated by low-speed sedimentation on neutral sucrose gradients after irradiation with 60Co gamma rays. Irradiation both in vivo and in vitro was used as a molecular probe of the constraints on DNA packaging in the bacterial chromosome. The number of domains of supercoiling was estimated to be approximately 180 per genome equivalent of DNA, based on measurements of relaxation caused by single-strand break formation in folded chromosomes gamma irradiated in vivo and in vitro. Similar estimates based on the target size of ribonucleic acid molecules responsible for maintaining the compact packaging of the nucleoid predicted negligible unfolding due to the formation of ribonucleic acid single-strand breaks at doses of up to 10 krad; this was born out by experimental measurements. Unfolding of the nucleoid in vitro by limit digestion with ribonuclease or by heating at 70 degrees C resulted in DNA complexes with sedimentation coefficients of 1,030 +/- 59S and 625 +/- 15S, respectively. The difference in these rates was apparently due to more complete deproteinization and thus less mass in the heated material. These structures are believed to represent intact, replicating genomes in the form of complex-theta structures containing two to three genome equivalents of DNA. The rate of formation of double-strand breaks was determined from molecular weight measurements of thermally unfolded chromosomal DNA gamma irradiated in vitro. Break formation was linear with doses up to 10 krad and occurred at a rate of 0.27 double-strand break per krad per genome equivalent of DNA (1,080 eV/double-strand break). The influence of possible nonlinear DNA conformations on these values is discussed.
Assuntos
Cromossomos Bacterianos/efeitos da radiação , Radioisótopos de Cobalto , DNA Bacteriano/efeitos da radiação , Escherichia coli/efeitos da radiação , Núcleo Celular/efeitos da radiação , DNA Bacteriano/análise , Escherichia coli/análise , Peso Molecular , Conformação de Ácido Nucleico , Ribonucleases/metabolismo , TemperaturaRESUMO
Cysteine was shown to be toxic to Salmonella typhimurium. The mechanism of this toxicity may be due, at least in part, to cysteine's ability to cause deoxyribonucleic acid strand scissions.
Assuntos
Cisteína/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Centrifugação com Gradiente de Concentração , DNA Bacteriano/metabolismo , Relação Dose-Resposta a Droga , Peróxido de Hidrogênio/metabolismo , Salmonella typhimurium/metabolismoRESUMO
31P NMR studies of intact cells and perchloric acid extracts are used to investigate the effect of ethanol on the bioenergetics and glycolysis of Clostridium thermocellum, an anaerobic bacterium potentially useful for the single step conversion of biomass to ethanol. Whole cells suspended in phosphate buffer and given a carbon source (cellobiose) at 60 degrees C rapidly establish a pH gradient across the membrane that can be monitored by the chemical shifts of inorganic phosphate in the exterior buffer and in the cytoplasm. Peak intensities can be related to phosphate active transport rates. Wild type bacteria and cells grown in inhibiting concentrations of ethanol establish similar pH gradients, but with slower kinetics and slower phosphate transport rates for the cells adapted to growth in ethanol. Direct addition of ethanol does not affect the rate of pH gradient formation or phosphate transport. Thus, while ethanol does not directly affect processes for energy conservation carried out by the membrane, adaptation to ethanol does alter membrane functions such as phosphate transport. 31P NMR spectra of perchloric acid extracts show that when wild type cells are adapted to grow in inhibiting concentrations of ethanol and then energized with cellobiose, sugar phosphate content is increased and the steady state distribution of glycolytic intermediates is altered. Nucleotide triphosphate/nucleotide diphosphate ratios are unaltered in these cells. These results strongly indicate that in C. thermocellum growth inhibition by ethanol is related to a blockage in glycolysis.
Assuntos
Clostridium/metabolismo , Etanol/farmacologia , Anaerobiose , Transporte Biológico/efeitos dos fármacos , Membrana Celular/metabolismo , Clostridium/efeitos dos fármacos , Fermentação , Hexosefosfatos/metabolismo , Cinética , Espectroscopia de Ressonância Magnética/métodos , Modelos Biológicos , Fosfatos/metabolismo , Especificidade da EspécieRESUMO
The recovery of several strains of Salmonella typhimurium LT-2 which had first been grown in minimal medium varies when the organisms are grown on minimal medium agar and complex medium agar. The strains tested included mutants with deficiencies in DNA-repair systems (uvrB-and rec-), a deep rough (rfa-) mutant, and a double mutant carrying both the uvrB- and the rfa-mutation. The uvrB- and rec-mutations imparted sensitivity to complex medium agar. The rfa-mutation suppressed the sensitivity of the uvrB-mutant to complex medium agar. Differences in colony-forming ability were not observed when the bacteria were first grown in the complex medium broth.
Assuntos
Meios de Cultura/toxicidade , Reparo do DNA , Salmonella typhimurium/crescimento & desenvolvimento , Mutação , Salmonella typhimurium/genéticaRESUMO
The feasibility of expressing repeated synthetic codons in bacterial cells was demonstrated by showing that repeated codons for proline were expressed in Escherichia coli. Recombinant DNA technology was used to clone synthetic polydeoxyguanylate:polydeoxycytidylate into the PstI site of plasmid pBR322. Recombinant plasmid pGC139 was shown by means of HaeIII restriction digestion to contain approximately 41 cloned base pairs; the cloned sequence was expressed as a fusion to an ampicillinase protein. The resulting protein, enriched in proline, was expressed from plasmid pGC139 in E. coli maxicells. Extension of this technology could lead to improvement in the production of amino acids and to nutritional enrichment of single-cell protein.