PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “BACTERIAL PROTEINS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources
PubMed2006

Distribution of bacterial proteins in biofilms formed by non-typeable Haemophilus influenzae.

The ability to preserve the fragile ultrastructural organization of bacterial biofilms using cryo-preparation methods for electron microscopy has enabled us to probe sections through non-typeable Haemophilus influenzae (NTHi) biofilms and determine the localization of NTHi-specific lipooligosaccharide (LOS) and proteins within these structures. Some of the proteins we examined are currently being considered as candidates for vaccine development, so it is important that their distribution and accessibility within the biofilms formed by NTHi be determined. We have localized LOS to the extracellular matrix (ECM) of the biofilm and the P6 outer membrane protein to the membrane of what appear to be viable bacteria within the biofilm. The Hap and HWM1/HMW2 adhesive proteins were associated with bacteria within the biofilm and were present in the biofilm ECM. The IgA1 protease is a secreted protein that was also associated with NTHi in the biofilm and was in the ECM, but was more concentrated in the top region of the biofilm, suggesting a role in protecting biofilm bacteria from antibody attack.

Adhesins, Bacterial↗
PubMed2004

Omp85, an evolutionarily conserved bacterial protein involved in outer-membrane-protein assembly.

The insertion of proteins into membranes generally requires the assistance of membrane proteins. A protein, designated Omp85 in Neisseria meningitidis, was shown to be required for the assembly of bacterial outer-membrane proteins. The protein is essential for the viability of the bacteria and is ubiquitous among Gram-negative bacteria. Omp85 depletion results in the accumulation of aggregates of unfolded outer-membrane proteins, and we argue that Omp85 is directly involved in outer-membrane-protein assembly. Omp85 shows sequence similarity with Toc75 of the chloroplast protein-import machinery, suggesting a common evolutionary origin.

Amino Acid Sequence↗
PubMed2002

RacA, a bacterial protein that anchors chromosomes to the cell poles.

Eukaryotic chromosomes are anchored to a spindle apparatus during mitosis, but no such structure is known during chromosome segregation in bacteria. When sister chromosomes are segregated during sporulation in Bacillus subtilis, the replication origin regions migrate to opposite poles of the cell. If and how origin regions are fastened at the poles has not been determined. Here we describe a developmental protein, RacA, that acts as a bridge between the origin region and the cell poles. We propose that RacA assembles into an adhesive patch at a centromere-like element near the origin, causing chromosomes to stick at the poles.

Bacillus subtilis↗
PubMed1983

[Effect of the content of plant crude protein in the ration on the utilization of urea by the milk cow. 1. Nitrogen digestibility and utilization of urea for bacterial protein synthesis in the rumen].

The utilisation of feed urea in the rumen was tested in 2 experiments with a total of 4 newly lactating dairy cows (13 . . . 15 and 17 . . . 19 kg resp. milk/animal and day) with rumen and duodenal re-entrant cannulae. With the energy supply remaining constant in each case, the rations in experiment A contained 8.7, 12.4 and 14.6 and those of experiment B 10.7, 13,7 and 17.1% crude plant protein in the dry matter. After the supplementation with 120 and 150 g resp. urea/animal and day there were 11.9, 15.7 and 17.8 (A) and 13.8, 16.7 and 20.2 (B) % resp. crude protein in the dry matter. The rations consisted of maize silage and a pelleted mixture of straw and concentrated feed (A) resp. maize silage, alfalfa hay and concentrated feed (B). They contained 10.3 . . . 10.6 (A) and 13.6 (B) kg dry matter with 5.6 . . . 6.0 (A) and 8.2 (B). With the increase of the crude protein level of the ration to 16.7 . . . 17.8, the absolute amount of non-NH3-N (NAN) in the duodenum increased as well. Between N-intake (g/d, x) and NAN-passage corrected by the amount of the endogenous quota (g/d, y) the relation y = 87.3 + 0.55 x (r = 0.80) could be established. NAN-passage (y) as related to N-intake decreased with the N-concentration in the dry matter of the ration (x) according to the equation y = 0.35 + 1.22x-1 (r = 0.57). 70, 62 and 61% (experiment A) and 55, 61 and 51% (experiment B) of the consumed amount of N were apparently absorbed in the intestines as NAN (without endogenous quota). The bacterial N-yield of the rumen (g, y), determined with diamino pimelic acid as microbe marker, was dependent on the consumed digestible organic matter (g, x) as follows: y = 67.3 + 0.021x (r = 0.69). There was no connection with the level of N-supply. The measuring results of the bacterial N-yield show that the utilisation rate of the urea-N decreased rapidly when there was more than 11 . . . 12% crude plant protein in the dry matter of the ration. For the tested ration type (570 . . . 600 EFUcattle/kg dry matter) the urea utilisation potential in the rumen for crude plant protein concentrations of 8.7, 10.7, 12.4, 13.4, 13.7, 14.6 and 17.1% in the dry matter was 13.0, 6.9, 4.1, 2.6, 1.3 and -9.6 g urea/kg dry matter.

Animal Feed↗
PubMed2004

Survey of bacterial proteins released in cheese: a proteomic approach.

During the ripening of Emmental cheese, the bacterial ecosystem confers its organoleptic characteristics to the evolving curd both by the action of the living cells, and through the release of numerous proteins, including various types of enzymes into the cheese when the cells lyse. In Emmental cheese these proteins can be released from thermophilic lactic acid bacteria used as starters like Lactobacillus helveticus, Lb delbruecki subsp. lactis and Streptococcus salivarius subsp. thermophilus and ripening bacteria such as Propionibacterium freudenreichii. The aim of this study was to obtain a proteomic view of the different groups of proteins within the cheese using proteomic tools to create a reference map. A methodology was therefore developed to reduce the complexity of cheese matrix prior to 2D-PAGE analysis. The aqueous phase of cheese was prefractionated by size exclusion chromatography, bacterial and milk proteins were separated and subsequently characterised by mass spectrometry, prior to peptide mass fingerprint and sequence homology database search. Five functional groups of proteins were identified involved in: (i) proteolysis, (ii) glycolysis, (iii) stress response, (iv) DNA and RNA repair and (v) oxidoreduction. The results revealed stress responses triggered by thermophilic lactic acid bacteria and Propionibacterium strains at the end of ripening. Information was also obtained regarding the origin and nature of the peptidases released into the cheese, thus providing a greater understanding of casein degradation mechanisms during ripening. Different peptidases arose from St thermophilus and Lb helveticus, suggesting that streptococci are involved in peptide degradation in addition to the proteolytic activity of lactobacilli.

Autolysis↗
PubMed2004

Highly phosphorylated bacterial proteins.

We show in Gram-negative and Gram-positive bacteria the appearance of highly acidic proteins, which are highly phosphorylated. This group of proteins includes many cellular proteins, such as chaperones, biosynthetic, and metabolic enzymes. These proteins accumulate under stress conditions or under conditions, which overload the proteolytic system. Pulse chase experiments using radioactive phosphate indicate that the phosphorylated proteins have a short half-life, suggesting that they could be degradation intermediates. Moreover, results from in vitro experiments in Escherichia coli indicated that ribosomal proteins become susceptible to proteolysis after polyphosphorylation. Therefore, it is possible that the highly phosphorylated proteins represent a group of proteins tagged for degradation by phosphorylation. Such a tagging process may be involved in a general bacterial degradation pathway.

Bacterial Proteins↗