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At least 19 recordsLinked to original sources
PubMed1986

Supplemental protein degradation, bacterial protein synthesis and nitrogen retention in sheep eating sodium hydroxide-treated straw.

1. Alkali (sodium hydroxide)-treated wheat straw was given to six rumen- and abomasal-cannulated sheep to study the rumen degradation of cotton-seed meal (CSM) and barley (B), and the effects of these supplements on nitrogen retention and efficiency of bacterial protein synthesis were measured. 2. N degradation, using porous synthetic (nylon) bags incubated within the rumen (P), and in vivo measurement determined from the abomasal flow of N (V), distinguished quantitatively between the two supplements. Estimates of P, corrected for fractional outflow rates/h (FOR), underestimated estimates of V when FOR of undegraded protein from the rumen (k) of 0.05 and 0.08 were used. Estimates of V for CSM and B were 70.9 and 80.8% respectively. 3. Intakes of alkali-treated straw were not affected by the supplements. Intakes of digestible organic matter (DOM) for the diets comprising alkali-treated straw alone (W), straw plus CSM (WC) and straw plus barley (WB) were 477, 575 and 590 g/d respectively (P less than 0.05) and organic matter (OM) apparently digested in the rumen (OMADR) was 339, 399 and 435 g/d respectively (P less than 0.05). 4. On W, WC and WB respectively, flows at the abomasum were 11.0, 14.0 and 13.3 g/d for bacterial N (P less than 0.05) and 0, 2.8 and 0.5 g/d for dietary supplemental N; g bacterial N/kg OMADR were 32.4, 35.6 and 30.9 (P greater than 0.05) and N balances were 2.37, 4.27 and 3.29 g/d (P less than 0.05) on the respective treatments. It was suggested that supplements increased total OM intake as a result of increased OM digested in the rumen rather than OM flow from the rumen.

Animal Feed↗
PubMed1999

Effects of level of feeding and ruminally undegraded protein on ruminal bacterial protein synthesis, escape of dietary protein, intestinal amino acid profile, and performance of dairy cows.

Six cannulated lactating cows were used in two replicated, concurrently run 3 x 3 Latin square experiment to study the interaction between level of feeding and diets differing in ruminally undegraded protein (RUP) on bacterial protein synthesis, ruminal escape of dietary protein, and flow of total and individual amino acids (AA) to the small intestine. Treatments consisted of three diets formulated to contain 69 g (HL), 53 g (HH), and 48 g (LL) of RUP per kilogram of DM, respectively. Measurements were made in early lactation, at high feeding level (19.3 kg DM/d), and repeated at late lactation (9.8 kg DM/d, low feeding level) with the same animals and diets. Decreasing feed intake increased (P < .05) the apparent digestibility of OM, NDF, and ADF in the rumen and the total tract, decreased (P < .05) ruminal liquid and particulate passage rate and total ruminal VFA concentration, and increased ruminal pH and ammonia concentration. Decreased level of intake reduced the (P < .05) efficiency of bacterial N synthesis (28.1 vs 23.7 g bacterial N/kg OM truly digested in the rumen) and decreased (P < .05) ruminal protein degradation rate measured with an in situ method. Duodenal flow of nonammonia nitrogen (NAN), and total AA were highest (P < .05) for the HL diet and lowest (P < .05) for the LL diet at the high feeding level. However, at the low feeding level, diet composition did not affect the amount of NAN or total AA passing to the small intestine. Diet HL increased the proportion of Met, His (P < .05), and Arg (P < .07) in the duodenal digesta at both feeding levels. When purines were used to calculate bacterial N synthesis, no differences between diets were detected. However, when diaminopimelic acid was used, highest bacterial N synthesis was detected for diet HH at the high feeding level. Diet HL supported the highest (P < .05) milk protein production at the high feeding level, and the highest (P < .05) milk protein content at the low feeding level. In conclusion, level of feeding and amount of RUP altered the amount and composition of AA presented to the cows.

Amino Acids↗
PubMed1990

The 26S rRNA binding ribosomal protein equivalent to bacterial protein L11 is encoded by unspliced duplicated genes in Saccharomyces cerevisiae.

Transformant phages expressing L15, a yeast ribosomal protein which binds to 26S rRNA and interacts with the acidic ribosomal proteins, were isolated by screening a yeast cDNA expression library in lambda gt11 with specific monoclonal antibodies. Using yeast DNA HindIII fragments that hybridize with the cDNA insert from the L15-expressing clones, minilibraries were prepared in pUC18, which were afterward screened with the same cDNA probe. In this way, plasmids carrying two different types of genomic DNA inserts were obtained. The inserts were subcloned and sequenced and we found a similar coding sequence in both cases flanked by 5' and 3' regions with very low homology. Sequences homologous to the consensus TUF-binding UAS boxes are present in the 5' flanking regions of both genes. Southern analysis revealed the presence of two copies of the L15 gene in the Saccharomyces cerevisiae genome, which are located in different chromosomes. The encoded amino acid sequence corresponds, as expected, to protein L15 and shows a high similarity to bacterial ribosomal protein L11.

Amino Acid Sequence↗
PubMed1992

Cell injury and death caused by bacterial protein toxins.

Bacterial protein toxins, such as Clostridium difficile toxin A and the Escherichia coli cytotoxic necrotizing factor 1 are known to exert their cytotoxic action via a modification of some cytoskeletal components. The changes in actin organization caused by these toxins appear to be the primary events in the mechanism leading to cell death.

Actins↗
PubMed2004

Probable epitopes: Relationships between myelin basic protein antigenic determinants and viral and bacterial proteins.

Nature holds numerous viral and bacterial proteins with regions of similarity to myelin basic protein antigenic determinants. Bioinformatic technology, including sequence similarity searches, may allow for the detection of biochemical and biophysical relationships between these peptides. Understanding these relationships is essential to understanding immune-mediated disease and, consequently, may be used to elucidate the etiology of pathological demyelinating diseases such as multiple sclerosis. Studies of experimental autoimmune encephalomyelitis have been used to identify antigenic determinants. We have used these determinants to search available databases of viral and bacterial proteins. Our results indicate numerous viral and bacterial protein segments with probabilistic sequence similarity to myelin basic protein antigenic determinants.

Amino Acid Sequence↗
PubMed1993

Novel targets and catalytic activities of bacterial protein toxins.

Among bacterial protein toxins with intracellular targets, tetanus and botulinum toxins form a group with unique properties. They are absolutely neurospecific and act in the cytosol of neurons. Recent evidence indicates that they are zinc proteases specific for proteins of the neuroexocytosis apparatus.

Amino Acid Sequence↗
PubMed1983

Purification and characterization of two ribosomal proteins of Saccharomyces cerevisiae. Homologies with proteins from eukaryotic species and with bacterial protein EC L11.

Two non-acidic proteins, extracted from the ribosomes of Saccharomyces cerevisiae using 1 M ammonium chloride in the presence of 50% ethanol, have been purified and characterized. Similar proteins are present in other eukaryotic ribosomes tested, as determined by two-dimensional gel electrophoresis and cross-reaction with antisera. One of the two yeast proteins, protein YL23, seems to be very well preserved during evolution, since antisera specific for YL23 cross-react with protein EC L11 from Escherichia coli. The structural similarity between these two proteins parallels a functional equivalence shown by the ability of the bacterial protein to reconstitute the activity of protein-deficient core particles from yeast. However, in contrast to protein EC L11, protein YL23 interacts with the yeast acidic proteins, forming a complex probably similar to the one made by bacterial protein EC L10 with proteins EC L7 and EC L12 in the E. coli ribosome. Protein YL23 might play similar roles to those of proteins EC L10 and EC L11 in bacteria.

Animals↗
PubMed1984

[Chemical and microbiological studies of the meat of broilers fed mixed feeds with a bacterial protein supplement].

Physico-chemical and microbiologic studies were carried out with meat of broilers that had been offered combined feed mixtures in which part of the soybean meal protein was replaced by microbial one through the incorporation of 4, 8, and 12 per cent industrial single cell protein. The bacterial protein was shown to have no adverse effect on the physico-chemical composition of poultry meat. Demonstrated was a trend toward the separation in individual layers of more fats in the carcass with the increase in the percent of biomass of the combined feed mixtures for poultry. Considering the content of total nitrogen, fats, and ashes in the poultry meat most expedient was the incorporation of 4 percent single-cell protein in the feed mixtures for broilers. No pathogenic and conditionally pathogenic organisms were found in the meat of broilers.

Animal Feed↗
PubMed2004

Subcellular sites for bacterial protein export.

Most bacterial proteins destined to leave the cytoplasm are exported to extracellular compartments or imported into the cytoplasmic membrane via the highly conserved SecA-YEG pathway. In the present studies, the subcellular distributions of core components of this pathway, SecA and SecY, and of the secretory protein pre-AmyQ, were analysed using green fluorescent protein fusions, immunostaining and/or immunogold labelling techniques. It is shown that SecA, SecY and (pre-)AmyQ are located at specific sites near and/or in the cytoplasmic membrane of Bacillus subtilis. The localization patterns of these proteins suggest that the Sec machinery is organized in spiral-like structures along the cell, with most of the translocases organized in specific clusters along these structures. However, this localization appears to be independent of the helicoidal structures formed by the actin-like cytoskeletal proteins, MreB or Mbl. Interestingly, the specific localization of SecA is dynamic, and depends on active translation. Moreover, reducing the phosphatidylglycerol phospholipids content in the bacterial membrane results in delocalization of SecA, suggesting the involvement of membrane phospholipids in the localization process. These data show for the first time that, in contrast to the recently reported uni-ExPortal site in the coccoïd Streptococcus pyogenes, multiple sites dedicated to protein export are present in the cytoplasmic membrane of rod-shaped B. subtilis.

Adenosine Triphosphatases↗
PubMed1979

M467: a murine IgA myeloma protein that binds a bacterial protein. I. Recognition of common antigenic determinants on Salmonella flagellins.

We have studied the binding of M467, an IgA murine myeloma protein, to flagellin from seven species of Salmonella. It was found that M467 was reacting with antigenic determinants that were common to all the flagellins studied. These determinants were not related to serotypic antigens. Electronmicrographs of unreduced M467 showed a variety of polymeric species bound to flagella in a manner that could produce immobilization as well as agglutination and precipitation through cross-linking of antigenic determinants. Immunodiffusion in agar gel revealed that M467 was recognizing more than one group of peptide determinants on the flagellins studied. Passive hemagglutination inhibition and a solid phase radioimmunoassay provided evidence that there were differences in binding avidities between M467 and the various Salmonella flagellins studied. It was concluded that M467 is binding more than one specific group of antigenic peptide determinants on flagellin molecules. Flagellin from four of the seven species of Salmonella studied were deficient in one or more of these determinants.

Animals↗
PubMed1985

Effects of sodium bicarbonate on nitrogen balance, bacterial protein synthesis and sites of nutrient digestion in sheep.

Two experiments were conducted to determine effects of sodium bicarbonate (NaHCO3) on nitrogen (N) balance, ruminal N metabolism and site and extent of nutrient digestion in sheep fed 75% concentrate diets. A 2 X 2 factorial arrangement of treatments was employed in both trials with experimental diets balanced for 10.5 or 12.0% crude protein and containing 0 or 3.5% NaHCO3. In experiment 1, 12 lambs were allotted to four diets for two periods in a randomized complete-block design. Dry matter (DM) digestibility was increased (P less than .10) by NaHCO3 supplementation, but organic matter (OM) digestibility was unaffected by treatment. Apparent N digestibility was not affected by NaHCO3 addition but was increased (P less than .0001) at the higher level of protein. Ruminal pH (4 h postfeeding) was increased (P less than .01) by NaHCO3 supplementation. Sodium bicarbonate had no effect on molar proportions of acetate or propionate, but increased molar proportion of butyrate (P less than .10) in ruminal fluid. Mean N retention (g/d) was increased (P less than .05) at the higher protein level, but was not affected by NaHCO3. In experiment 2, four ruminal- and duodenal-cannulated wethers were utilized in a 4 X 4 Latin square design. Sodium bicarbonate addition increased ruminal pH (P less than .05) 2 h postfeeding but did not affect ruminal ammonia (NH3) levels, total VFA concentration or ruminal fluid dilution rates. Molar proportion of acetate was increased (P less than .01) by NaHCO3 at the lower protein level. Ruminal particulate dilution rates were increased (P less than .05) by NaHCO3 addition. Ruminal, postruminal and apparent total tract digestibilities of OM and neutral detergent fiber (NDF) were unaffected by NaHCO3 supplementation. Sodium bicarbonate decreased (P less than .05) ruminal starch digestion at the lower protein level but increased (P less than .05) it at the higher protein level. Bacterial N flow (g/d) at the duodenum and efficiency of bacterial protein synthesis were increased (P less than .10) by NaHCO3 additions.

Animal Nutritional Physiological Phenomena↗
PubMed1993

Homology between the HrpO protein of Pseudomonas solanacearum and bacterial proteins implicated in a signal peptide-independent secretion mechanism.

A region of approximately 22 kb of DNA defines the large hrp gene cluster of strain GMI1000 of Pseudomonas solanacearum. The majority of mutants that map to this region have lost the ability to induce disease symptoms on tomato plants and are no longer able to elicit a hypersensitive reaction (HR) on tobacco, a non-host plant. In this study we present the complementation analysis and nucleotide sequence of a 4772 bp region of this hrp gene cluster. Three complete open reading frames (ORFs) are predicted within this region. The corresponding putative proteins, HrpN, HrpO and HpaP, have predicted sizes of 357, 690 and 197 amino acids, respectively, and predicted molecular weights of 38,607, 73,990 and 21,959 dalton, respectively. HrpN and HrpO are both predicted to be hydrophobic proteins with potential membrane-spanning domains and HpaP is rich in proline residues. A mutation in hpaP (for hrp associated) does not affect the HR on tobacco or the disease on tomato plants. None of the proteins is predicted to have an N-terminal signal sequence, which would have indicated that the proteins are exported. Considerable sequence similarities were found between HrpO and eight known or predicted prokaryotic proteins: LcrD of Yersinia pestis and Y. enterocolitica, FlbF of Caulobacter crescentus, FlhA of Bacillus subtilis, MxiA and VirH of Shigella flexneri, InvA of Salmonella typhimurium and HrpC2 of Xanthomonas campestris pv. vesicatoria. These homologies suggest that certain hrp genes of phytopathogenic bacteria code for components of a secretory system, which is related to the systems for secretion of flagellar proteins, Ipa proteins of Shigella flexneri and the Yersinia Yop proteins. Furthermore, these homologous proteins have the common feature of being implicated in a distinct secretory mechanism, which does not require the cleavage of a signal peptide. The sequence similarity between HrpO and HrpC2 is particularly high (66% identity and 81% similarity) and the amino acid sequence comparison between these two proteins presented here reveals the first such sequence similarity to be shown between Hrp proteins of P. solanacearum and X. campestris. An efflux of plant electrolytes was found to be associated with the interactions between P. solanacearum and both tomato and tobacco leaves. This phenomenon may be part of the mechanism by which hrp gene products control and determine plant-bacterial interactions, since hrpO mutants induced levels of leakage which were significantly lower than those induced by the wild type on each plant.

Amino Acid Sequence↗
PubMed1985

Digestion, absorption and utilization of single-cell protein by the preruminant calf. The true digestibility of milk and bacterial protein and the apparent digestibility and utilization of their constituent amino acids.

Two experiments of Latin square design were made, each with four Friesian bull calves fitted with re-entrant duodenal and ileal cannulas at 4-10 d of age. The calves were used to study the effect of giving milk-substitutes containing 0, 300, 500 and 700 g bacterial protein (Pruteen)/kg total protein on apparent digestibility of nitrogen fractions and amino acids and true digestibility of 3H-labelled milk protein and 35S-labelled bacterial protein in the small intestine. A third experiment of Latin square design with four intact Friesian calves was used to measure apparent digestibility of nutrients throughout the alimentary tract and retention of N, calcium and phosphorus. At the duodenum, volume of outflow, its pH, and outflow of total-N(TN), protein-N (PN) and non-protein-N (NPN) decreased with time after feeding. At the ileum, volume of outflow and TN outflow were unaffected by time after feeding but PN outflow decreased; NPN outflow at the ileum increased to a maximum 6 h after feeding and then declined. Increased inclusion of Pruteen did not affect the volume of outflow at the duodenum or ileum, but duodenal PN outflow increased. At the ileum, pH values were lower and TN, PN and NPN outflows were higher with increasing concentration of Pruteen in the diet. Apparent digestibility in the small intestine tended to decrease with greater amounts of Pruteen, but was only significant for NPN. Apparent digestibility from mouth to ileum significantly decreased for TN and PN as Pruteen inclusion increased. Amino acid concentration in duodenal outflow, with the exception of that of arginine, reflected intake. The total amount of each amino acid in ileal outflow increased and the apparent digestibility of most amino acids decreased with greater amounts of Pruteen in the diet. Apparent digestibility of nucleic acid-N from Pruteen was very high. True digestibility in the small intestine and between mouth and ileum of 3H-labelled milk protein was high and did not differ between dietary treatments. True digestibility of 35S-labelled Pruteen was low for the milk-protein diet and tended to increase linearly as more dietary Pruteen was included. Dry matter concentration in faeces and a high apparent digestibility throughout the whole alimentary tract of carbohydrates did not differ between treatments.(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗
PubMedDate not supplied

Identification of protein complexes by comparative analysis of yeast and bacterial protein interaction data.

Mounting evidence shows that many protein complexes are conserved in evolution. Here we use conservation to find complexes that are common to the yeast S. cerevisiae and the bacteria H. pylori. Our analysis combines protein interaction data that are available for each of the two species and orthology information based on protein sequence comparison. We develop a detailed probabilistic model for protein complexes in a single species and a model for the conservation of complexes between two species. Using these models, one can recast the question of finding conserved complexes as a problem of searching for heavy subgraphs in an edge- and node-weighted graph, whose nodes are orthologous protein pairs. We tested this approach on the data currently available for yeast and bacteria and detected 11 significantly conserved complexes. Several of these complexes match very well with prior experimental knowledge on complexes in yeast only and serve for validation of our methodology. The complexes suggest new functions for a variety of uncharacterized proteins. By identifying a conserved complex whose yeast proteins function predominantly in the nuclear pore complex, we propose that the corresponding bacterial proteins function as a coherent cellular membrane transport system. We also compare our results to two alternative methods for detecting complexes and demonstrate that our methodology obtains a much higher specificity.

Bacterial Proteins↗
PubMed2003

A bioinformatic approach to the identification of bacterial proteins interacting with Toll-interleukin 1 receptor-resistance (TIR) homology domains.

Members of the Toll-like receptor (TLR) family are currently under intense scrutiny for their role in the sampling and recognition of pathogens. It has already been reported that both vaccinia virus and Yersinia spp. express proteins that help them evade the TLR mediated immune response, acting through the Toll-interleukin-1 receptor-resistance (TIR) domain and leucine-rich repeat region of the host TLRs respectively. The TIR domain is involved in the dimerisation of the TLRs and their complexation with their adapter molecules. We tested here the hypothesis that bacteria have the ability to secrete proteins containing similar motifs to the intracellular TIR domains that are involved in the TIR-TIR interaction necessary for the subsequent signal transmission. Based upon their sequence homology, proteins expressing TIRs have been divided into three sub-classes, based around the TLRs, the TLR adapter proteins, and the interleukin-1 and -18 adapter proteins. The highly conserved regions from these separate sub-families were then used to identify similar bacterial proteins. The bacterial proteins identified were then included in an iterative MEME-BLAST process to broaden the search. Tollip, a known TLR antagonist and adapter protein, was included in this investigation although it does not fit into any of the three sub-classes outlined above. If suitable bacterial proteins had been identified, it would signify that certain bacteria had evolved a mechanism to aid them in avoiding detection by the innate immune system acting through the TIR domains. At this stage one has to conclude that there is no evidence currently available suggesting such a mechanism, when using the strategy applied here.

Adaptor Proteins, Signal Transducing↗
PubMed1993

In vivo control of redox potential during protein folding catalyzed by bacterial protein disulfide-isomerase (DsbA).

The formation of disulfide bonds in Escherichia coli is catalyzed by periplasmic protein disulfide-isomerase (DsbA). When the alpha-amylase/trypsin inhibitor from Ragi, a protein containing five intramolecular disulfide bridges, is secreted into the periplasm of E. coli, large amounts of misfolded inhibitor with incomplete or incorrect disulfides are accumulated. Folding of the inhibitor in the periplasm is not improved when DsbA is coexpressed and cosecreted. However, an up to 14-fold increase in correctly folded inhibitor is observed by co-expression of DsbA in conjugation with the addition of reduced glutathione to the growth medium. This peptide acts as a disulfide-shuffling reagent and can pass the outer membrane of E. coli. Since the influence of DsbA on the folding yield of the inhibitor is reduced in the presence of oxidized glutathione, the in vivo function of DsbA appears to be dependent on the ratio between oxidizing and reducing thiol equivalents in the periplasm. The high stability of thiol reagents against air oxidation during growth of E. coli allows the investigation of oxidative protein folding in vivo under controlled, thiol-dependent redox conditions.

Amino Acid Sequence↗