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排序方式: 共有1190条查询结果,搜索用时 421 毫秒
1.
D.A.M. da Silva M.S. Fernandes E.H. Endo A.C.P. Vital E.A. Britta M.E. Favero J.C. Castro P.T. Matumoto-Pintro B.P. Dias Filho C.V. Nakamura M. Machinski Junior J.M.G. Mikcha B.A. de Abreu Filho 《Letters in applied microbiology》2021,72(1):41-52
The use of rosemary essential oil (RO) and its combination with nisin (RO+N) in preventing the multiplication of Alicyclobacillus acidoterrestris in orange juice was evaluated. The minimum inhibitory and bactericidal concentrations (MIC and MBC) for RO were both 125 μg ml−1 while RO+N displayed a synergistic effect. The use of RO and RO+N at concentrations of 1, 4 and 8× MIC in orange juice for 96 h was evaluated in terms of their sporicidal effectiveness. With regard to the action against A. acidoterrestris spores, RO at 8× MIC was sporostatic, whereas RO+N at 1× MIC was sporicidal. Morphological changes in the structure of the micro-organism after treatment were also observed by microscopy. Furthermore, flow cytometric analysis showed that most cells were damaged or killed after treatment. In general, the antioxidant activity after addition of RO+N decreased with time. The results demonstrate that using the combination of RO and nisin can prevent the A. acidoterrestris growth in orange juice. 相似文献
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3.
M. I. M. Fernandes S. Zucoloto E. F. Collares F. Ferriolli Filho 《Virchows Archiv. B, Cell pathology including molecular pathology》1991,60(1):119-122
The objective of this investigation was to study the morphometry of the epithelial mucosa in the chronic phase ofT. cruzi infection. Nine young female Wistar rats were inoculated withT. cruzi. Ten months after inoculation the animals were sacrificed and the proximal colon was collected for morphometric measurements
of the thickness of the muscle layers, the number of neurons in the myenteric plexus, the crypt cell population (CCP), crypt
cell production per crypt (CCPC) and turnover time (TT) of the epithelium. There was no muscle layer hypertrophy but there
was significant denervation in the group inoculated withT. cruzi, which also showed hyperplasia of the epithelium. The data suggest that denervation of the myenteric plexus did not induce
hypertrophy of the propria muscle layer itself but altered the morphometry of the colonic epithelium inT. crwzi-infected animals, with increased development of CCP and TT. It is possible that this epithelial hyperplasia, as a consequence
of a longer crypt cell TT, increased the absorption and secretion activities of the colon, which in turn may participate in
the genesis of the enteromegalies observed in the chronic phase of Chagas’ Disease. 相似文献
4.
An ESR study of nitrosyl-Aplysia brasiliana myoglobin and nitrosyl annelidae Glossoscolex paulistus erythrocruorin 总被引:1,自引:0,他引:1
I Caracelli N C Meirelles M Tabak O Baffa Filho O R Nascimento 《Biochimica et biophysica acta》1988,955(3):315-320
The nitrosyl derivatives of Annelidae Glossoscolex paulistus hemoglobin (an earth worm erythrocruorin (Ec AGp)) and Aplysia brasiliana myoglobin (Mb Apb) are studied using ESR spectroscopy. These two proteins have a quite similar ESR spectra at 100 K, but a different temperature behaviour. The temperature dependence of the nitrosyl Mb Apb spectrum is in good agreement with the Boltzmann distribution. In the case of nitrosyl-Ec AGp, the results are explained by the existence of two types of spectrum in thermodynamic equilibrium, with delta H = 9.08 kJ/mol, delta S = 47.15 J/mol and T1/2 = 193 K. There is a great similarity of the nitrosyl-Ec AGp spectra with those reported for elephant myoglobin, suggesting the presence of the same heme environment with a glutamine residue in the distal site. The pH dependence of the spectrum of nitrosyl-Mb Apb shows that the affinity of nitrosyl binding is higher at high pH (7.3) than at low pH (4.6). The ESR parameters are the same for these two pH values. 相似文献
5.
A J de Araújo L F Ferreira U E Confalonieri L Nu?ez B M Ribeiro Filho 《Memórias do Instituto Oswaldo Cruz》1985,80(2):141-143
Enterobius vermicularis eggs were found in human coprolites collected in the archaeological site of Caserones, Tarapaca Valley, Chile, dating from 400 BC to 800 AD. The human pinworm had already been found in other pre-historic archaeological sites in America, and its introduction in this continent is discussed. 相似文献
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The possibility of ecosystem boundary changes in northern Brazilian Amazonia during the Holocene period was investigated using soil organic carbon isotope ratios. Determination of past and present fluctuations of the forest-savanna boundary involved the measurement of natural 13C isotope abundance, expressed as 13C, in soil organic matter (SOM). SOM 13C analyses and radiocarbon dating of charcoal fragments were carried out on samples derived from soil profiles taken along transects perpendicular to the ecotonal boundary. SOM 13C values in the upper soil horizons appeared to be in equilibrium with the overlying vegetation types and did not point to a movement of the boundary during the last decades. However, 13C values obtained from deeper savanna and forest soil layers indicated that the vegetation type has changed in the past. In current savanna soil profiles, we observed the presence of mid-Holocene charcoals derived from forest species: fire frequency at that time was probably greater, and more extensive savanna may have resulted. Isotope data and the presence of these charcoals thus suggest that the forest-savanna boundary has shifted significantly in the recent Holocene period, forest being more extensive during the early Holocene than today. During the middle Holocene, the forest could have strongly regressed, and fires appeared, with a maximum development of the savanna vegetation. At the beginning of the late Holocene, the forest may have invaded a part of this savanna, and fires occurred again. 相似文献
8.
WhileEscherichia coli is common as a commensal organism in the distal ileum and colon, the presence of colonization factors (CF) on pathogenic strains ofE. coli facilitates attachment of the organism to intestinal receptor molecules in a species- and tissue-specific fashion. After the initial adherence, colonization occurs, and the involvement of additional virulence determinants leads to illness. EnterotoxigenicE. coli (ETEC) is the most extensively studied of the five categories ofE. coli that cause diarrheal disease, and has the greatest impact on health worldwide. ETEC can be isolated from domestic animals and humans. The biochemistry, genetics, epidemiology, antigenic characteristics, and cell and receptor binding properties of ETEC have been extensively described. Another major category, enteropathogenicE. coli (EPEC), has virulence mechanisms, primarily effacement and cytoskeletal rearrangement of intestinal brush borders, that are distinct from ETEC. An EPEC CF receptor has been purified and characterized as a sialidated transmembrane glycoprotein complex directly attached to actin, thereby associating CF-binding with host-cell response. Three, additional categories ofE. coli diarrheal disease, their colonization factors and their host cell receptors are discussed. It appears that biofilms exist in the intestine in a manner similar to oral bacterial biofilms, and thatE. coli is part of these biofilms as both commensals and pathogens.Abbreviations CF
colonization factor
- CFA
Colonization Factor Antigen
- CS
coli-surface-associated antigen
- EAggEC
enteroaggregativeE. coli
- ECDD
E. coli diarrheal disease
- EHEC
enterohemorrhagicE. coli
- EIEC
enteroinvasiveE. coli
- EPEC
enteropathogenicE. coli
- ETEC
enterotoxigenicE. coli
- Gal
galactose
- GalNAc
N-acetyl galactosamine
- LT
heat-labile toxin
- NeuAc
N-acetyl neuraminic acid
- PCF
Putative colonization factor
- RBC
red blood cells
- SLT
Shiga-like toxin
- ST
heat-stable toxin 相似文献
9.
DNA sequences were determined for three to five alleles of the bride-of-
sevenless (boss) gene in each of four species of Drosophila. The product of
boss is a transmembrane receptor for a ligand coded by the sevenless gene
that triggers differentiation of the R7 photoreceptor cell in the compound
eye. Population parameters affecting the rate and pattern of molecular
evolution of boss were estimated from the multinomial configurations of
nucleotide polymorphisms of synonymous codons. The time of divergence
between D. melanogaster and D. simulans was estimated as approximately 1
Myr, that between D. teissieri and D. yakuba as approximately 0.75 Myr, and
that between the two pairs of sibling species as approximately 2 Myr. (The
boss genes themselves have estimated divergence times approximately 50%
greater than the species divergence times.) The effective size of the
species was estimated as approximately 5 x 10(6), and the average mutation
rate was estimated as 1-2 x 10(-9)/nucleotide/generation. The ratio of
amino acid polymorphisms within species to fixed differences between
species suggests that approximately 25% of all possible single-step amino
acid replacements in the boss gene product may be selectively neutral or
nearly neutral. The data also imply that random genetic drift has been
responsible for virtually all of the observed differences in the portion of
the boss gene analyzed among the four species.
相似文献
10.
Cardoso RA Filho AA Melo MC Lyerly DM Wilkins TD Lima AA Ribeiro RA Souza GE 《Mediators of inflammation》1996,5(3):183-187
This study investigated the ability of Clostridium difficile toxin B, isolated from the VPI 10463 strain, to induce fever and neutrophilia in rats. Intravenous injection of toxin B (0.005-0.5 mug/kg) evoked a dose-dependent increase in body temperature. The febrile response to 0.5 mug/kg of the toxin started in 2.5 h, peaked at 5 h, and subsided fully within 24 h. Toxin B also induced a dosedependent neutrophilia. Pretreatment with indomethacin (2 mg/kg, i.p.) did not affect the neutrophilia induced by toxin B, but significantly reduced the febrile response measured 4 to 8 h after toxin B injection. Dexamethasone (0.5 mg/ kg) also markedly diminished the febrile response induced by toxin B. These results show that Clostridium difficile toxin B induced a febrile response susceptible to inhibition by dexamethasone and indomethacin. Furthermore, they suggest that prostaglandins are not involved in the neutrophilia caused by this toxin. 相似文献