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PubMed1984

[Quality of meat from lambs fattened on feed mixtures with added bacterial protein].

Physico-chemical, microbiologic, and histologic investigations were carried out with meat and parenchymal organs of lambs offered feed mixtures with a supplement of bacterial protein on methanol basis in fattening the animals up to 35 kilograms. The addition of 5 per cent bacterial protein which replaced in terms of protein equivalent 60 per cent of the sunflower oil meal and totally the amount of urea in the mixtures had no negative effect on the physical and chemical composition of the meat and its biologic value. Histologically, no degenerative changes in the skeletal muscles and parenchymal organs were found. There was hypofunction of the thyroid gland in the test lambs. No pathogenic and occasionally pathogenic organisms were found in the sampled meat and organs.

Animal Feed↗
PubMed1984

Use of isoelectric focusing of bacterial proteins for characterisation of strains of motile anaerobic "corroding" bacteria isolated from soft tissue infections in cats and dogs.

Isoelectric focusing of bacterial proteins in 1 mm thick agarose gels and ultrastructural analysis of cell walls were used to facilitate characterisation of motile "corroding" bacteria from subcutaneous abscesses and pyothorax infections from cats and dogs. Some of the motile "corroding" rods had ultrastructural cell wall features identical with Wolinella recta described from human periodontal pockets. Other strains had the more conventional cell wall ultrastructure of Gram negative bacteria. Isoelectric focusing of bacterial proteins divided the motile "corroding" strains into two groups. These groups correlated with the ultrastructural appearance of the cell walls. It is considered that isoelectric focusing techniques using 1 mm thick agarose gels may provide a more rapid method for ultimate differentiation of these organisms than other methods described so far.

Animals↗
PubMed2002

On-probe digestion of bacterial proteins for MALDI-MS.

On-probe digestion combined with MALDI mass spectrometry is studied as a rapid method for the analysis and identification of bacterial proteins. The use of trypsin adsorbed to the probe surface reduces the digestion time from hours to minutes. A high amount of trypsin must be applied to the probe for the successful digestion of bacterial proteins. Mass spectra of the digest contain a number of low-mass digest fragments. Several components of a B. subtilis bacterial digest can be identified through postsource decay and database searching.

Bacillus subtilis↗
PubMed2003

Identification of beta-subunit of bacterial RNA-polymerase--a non-species-specific bacterial protein--as target of antibodies in primary biliary cirrhosis.

Several observations suggest that bacteria induce autoimmunity in primary biliary cirrhosis (PBC). Since no PBC-specific bacterial species could be identified, it can be speculated that the triggers are non-species-specific bacterial proteins. This hypothesis would imply that several or even all bacterial species can trigger PBC. Therefore, we investigated whether PBC exhibits immune reactions to non-species-specific bacterial antigens. Yersinia enterocolitica O3 was screened for the presence of proteins that were labeled by immunoblotting using PBC sera. We focused our investigations on a 160-kDa protein, which was further enriched and characterized by partial N-terminal amino acid sequencing. The prevalence of antibodies to this protein was determined by immunoblotting in a variety of diseases. The 160-kDa protein was identified as the beta-subunit of bacterial RNA-polymerase, a highly conserved bacterial protein with a very high degree of sequence identity among all bacterial species. Antibodies to the beta-subunit of bacterial RNA polymerase were specific for this protein. Until now no mammalian protein could be found that cross-reacts with these antibodies. The prevalence of antibodies to the beta-subunit of bacterial RNA polymerase (ARPA) using the protein from Yersinia enterocolitica O3 (serum dilution 1:1000) was: healthy controls (HC, N = 101) 7.9%, primary biliary cirrhosis (PBC, N = 61) 32.8%, autoimmune hepatitis type 1 (AIH, N = 46) 26.1%, alcoholic liver cirrhosis (ALC, N = 44) 9.1%, Crohn's disease (CD, N = 38) 7.9%, ulcerative colitis (UC, N = 24) 8.3%, primary sclerosing cholangitis + UC (PSC/UC, N = 11) 0%, acute yersiniosis (Yers, N = 36) 19.4%, acute infection with Campylobacter jejuni (Camp, N = 10) 0%, acute Q-fever (QF, N = 16) 6.25%, chronic hepatitis C (HCV, N = 39) 7.7%, c-ANCA-positive vasculitis (Vasc, N = 40) 15%, systemic lupus erythematosus (SLE, N = 28) 10.7%, and malaria tropica (MT, N = 24) 16.7%. There was no significant difference between PBC and AIH. The group of autoimmune liver diseases (PBC + AIH, N = 107, 29.9%) differed highly significantly from HC, chronic inflammatory bowel diseases (CD + UC + PSC/UC, N = 73, 6.8%), ALC, and HCV and also differed significantly (P = 0.01) from the group with bacterial and parasitic diseases (Yers + Camp + QF + MT, N = 86,13.95%) and from the group with Vasc + SLE (N = 68,13.2%). Testing of ARPA using the protein from E. coli yielded nearly identical results. In conclusion, an increased prevalence of antibodies to the beta-subunit of bacterial RNA polymerase, a highly conserved non-species-specific bacterial protein, can be found in primary biliary cirrhosis, but also in autoimmune hepatitis type I. These findings do not add an argument for a bacterial trigger of PBC. Rather, they suggest that ARPA belong to the pool of natural antibodies that are up-regulated in autoimmune liver diseases.

Antibodies, Bacterial↗
PubMedDate not supplied

Bacterial protein kinases that recognize tertiary rather than primary structure?

While all characterized eukaryotic protein kinases that phosphorylate hydroxy aminoacyl residues in proteins recognize primary structure, certain bacterial protein kinases are proving to recognize tertiary structure. It is proposed that these latter enzymes evolved independently of the superfamily of the former protein kinases and that their modes of target protein recognition and action are entirely different.

Gram-Positive Bacteria↗
PubMed1984

[Fatty acid content of the lipid fraction of the meat of chickens fed mixed feeds with added bacterial protein].

Studies were carried out to establish the content of fatty acids in the lipid fraction of the meat of birds that were given combined feeds with the supplement of bacterial protein. A Perkin Elmer gas chromatograph with a flame-ionization detector were used to evaluate the fatty acid content. It was found that with the increase in the bacterial protein content of the feed mixtures there was a rising trend in the sum total of the unsaturated fatty acids (C16:1, C18:1, C18:2) and a lowering one of the saturated fatty acids (C14, C16, C18) as against their content in the meat of the control group.

Animal Feed↗
PubMed2003

Bacterial protein toxins and inflammation.

Although human mucosal linings are continuously exposed to microbes, the microbes rarely induce disease. This is because mucosal surfaces are protected by a first line of defence termed the innate immunity system. Inflammatory processes are activated as a consequence of a complex interplay between microbes and host target cells. Although inflammation is essential for clearing out infectious agents, it can also be harmful to the host and is therefore subjected to tight control at multiple levels. It was recently discovered that the bacterial protein toxin alpha-haemolysin (HlyA), secreted by uropathogenic Escherichia coli, induces constant, low-frequency Ca2+ oscillations in renal epithelial cells. Ca2+ oscillation occurs at a characteristic periodicity of 12 min, and affects gene expression in target epithelial cells. Specifically, the proinflammatory cytokine interleukin-6 (IL-6) and chemokine IL-8 were induced by HlyA-induced Ca2+ oscillations. A few additional bacterial protein toxins have been reported to induce Ca2+ oscillations in target epithelial cells, although their effects are poorly understood. However, the pioneering work on HlyA demonstrates a novel feature of bacterial protein toxins on host target cells: as inducers of second messenger responses which fine-tune gene expression in target epithelial cells.

Bacterial Toxins↗
PubMed1998

Fusion of Chlamydia trachomatis-containing inclusions is inhibited at low temperatures and requires bacterial protein synthesis.

The human pathogen Chlamydia trachomatis is an obligate intracellular bacterium with a unique developmental cycle. Within the host cell cytoplasm, it resides within a membrane-bound compartment, the inclusion. A distinguishing characteristic of the C. trachomatis life cycle is the fusion of the chlamydia-containing inclusions with each other in the host cell cytoplasm. We report that fusion of inclusions does not occur at 32 degreesC in multiple mammalian cell lines and with three different serovars of C. trachomatis. The inhibition of fusion was inclusion specific; the fusion with sphingolipid-containing secretory vesicles and the interaction with early endosomes were unaffected by incubation at 32 degreesC. The inhibition of fusion of the inclusions was not primarily the result of delayed maturation of the inclusion, as infectious progeny was produced in host cells incubated at 32 degreesC, and the unfused inclusions remained competent to fuse up to 48 h postinfection. The ability to reverse the inhibition of fusion by shifting the infected cells from 32 to 37 degreesC allowed the measurement of the rate and the time of fusion of the inclusions after entry of the bacteria. Most significantly, we demonstrate that fusion of inclusions with each other requires bacterial protein synthesis and that the required bacterial protein(s) is present, but inactive or not secreted, at 32 degreesC.

Animals↗
PubMed1986

The secY protein can act post-translationally to promote bacterial protein export.

Conditionally lethal Escherichia coli mutants in secY (prlA) show defective export of proteins to the periplasm and outer membrane. It has been proposed that this gene and other sec genes must act on pro-OmpA at an early stage of protein synthesis in order to allow later translocation to occur. We have described a temperature-sensitive mutation in which the secYts function is impaired at the nonpermissive temperature (Ito, K. (1984) Mol. Gen. Genet. 197, 204-208). A plasmid bearing the wild-type secY gene under the control of the lactose operon (Shiba, K., Ito, K., Yura, T., and Cerretti, D. P. (1984) EMBO J. 3, 631-635) has been introduced into this mutant strain. We now report that the in vivo chase of pulse-labeled full length pro-OmpA to mature OmpA is accelerated by inducing the synthesis of the wild-type secY protein at the end of the period of pulse labeling. We have also assayed the requirements for secY function for in vitro protein translocation. Membranes derived from secY ts cells which were incubated at 42 degrees C were inactive in vitro in the post-translational uptake and processing of pro-OmpA. Thus, the secY protein can act post-translationally, enhancing the translocation of completed pro-OmpA polypeptide chains across the plasma membrane.

Bacterial Proteins↗
PubMedDate not supplied

Antineutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis after immunisation with bacterial proteins.

OBJECTIVE: There is circumstantial evidence for a role for infections in the development of the small vessel vasculitides associated with antineutrophil cytoplasmic antibodies (ANCA). The aim of this study was to determine whether the immunisation of rats with bacterial proteins could result in circulating ANCA, T cells with specificity for ANCA antigens, and a systemic vasculitis. METHODS: Adult male Wistar rats were immunised with pasteurised sonicated S. aureus (n = 7), E. coli (n = 8), purified protein derivative (PPD, n = 5), myeloperoxidase (MPO, n = 5) or phosphate-buffered saline (PBS, n = 5), in complete and in incomplete Freund's adjuvant. ANCA were assayed by indirect immunofluorescent (IIF) examination of normal rat neutrophils, and in ELISAs using human proteinase 3 (PR3), MPO and bactericidal/permeability-inreasing protein (BPI). The T cell response to PR3, MPO and BPI was assessed by a whole blood T cell proliferative assay in vitro, and by a delayed type hypersensitivity (DTH) response in vivo. Kidney and bowel were examined histologically for evidence of vasculitis and colitis. RESULTS: One rat from each group immunised with S. aureus or E. coli developed pauciimmune segmental glomerular sclerosis. The rat immunised with E. coli had additionally an arteritis affecting renal interlobular and gut vessels. This rat had circulating C-ANCA, that produced granular cytoplasmic neutrophil fluorescence with central accentuation, but the target antigen could not be determined in ELISAs using human PR3, MPO or BPI. In animals immunised with S. aureus or E. coli, there was no significant T cell proliferative or DTH response specific for human PR3, MPO or BPI. CONCLUSION: The development of ANCA and vasculitis in a rat immunised with bacterial proteins indicates that the relationship between infections and ANCA should be investigated further.

Animals↗
PubMed1988

Bacterial proteins with N-terminal leader sequences resembling mitochondrial targeting sequences of eukaryotes.

Amphipathic, alpha-helical, leader sequences, analogous to those that direct nuclear-encoded eukaryotic proteins into mitochondria, have been found in one and only one class of bacterial integral membrane proteins. These bacterial proteins are the sugar permeases of the phosphoenolpyruvate-dependent phosphotransferase system. The amphipathic leader sequence in each of these proteins is terminated by a helix breaker, either a prolyl residue or 2 adjacent glycyl residues. Preliminary evidence suggests that these leader sequences function to target the proteins to the envelope fraction of the prokaryotic cell during their biosynthesis.

Amino Acid Sequence↗
PubMed2002

Dependence of bacterial protein adhesins on toll-like receptors for proinflammatory cytokine induction.

Toll-like receptors (TLRs) are important signal transducers that mediate inflammatory reactions induced by microbes through pattern recognition of virulence molecules such as lipopolysaccharide (LPS) and lipoproteins. We investigated whether proinflammatory cytokine responses induced by certain bacterial protein adhesins may also depend on TLRs. In differentiated THP-1 mononuclear cells stimulated by LPS-free recombinant fimbrillin (rFimA) from Porphyromonas gingivalis, cytokine release was abrogated by monoclonal antibodies (MAbs) to CD14 and TLR4 but not to TLR2. Similar experiments using anti-beta2 integrin MAbs suggested that beta2 integrins (CD11/CD18) also play a role in cytokine induction by rFimA or native fimbriae. Minor fimbriae (distinct from the fimA-encoded major fimbriae) of P. gingivalis induced proinflammatory cytokine release in a CD14- and TLR2-dependent mode. Cytokine induction by BspA, a leucine-rich repeat protein from Bacteroides forsythus, depended heavily on CD14 and TLR2. We also found that the ability of the streptococcal protein AgI/II to stimulate cytokine release depended partially on CD14 and TLR4, and the AgI/II segment that possibly interacts with these receptors was identified as its N-terminal saliva-binding region. When THP-1 cells were exposed to rFimA for 24 h, surface expression of CD14 and CD18 was decreased and the cells became hyporesponsive to cytokine induction by a second challenge with rFimA. However, tolerance induction was abolished when the THP-1 cells were pretreated with rFimA in the presence of either anti-CD14 MAb or anti-TLR4 MAb. Induction of cross-tolerance between rFimA and LPS correlated with downregulation of the pattern recognition receptors involved. Our data suggest that the CD14-TLR2/4 system is involved in cytokine production and tolerance induction upon interaction with certain proinflammatory bacterial protein adhesins.

Adhesins, Bacterial↗
PubMed1999

Participation of CD1 molecules in the presentation of bacterial protein antigens in humans.

Human CD1 molecules, expressed on the surface of professional antigen-presenting cells (including dendritic cells, Langerhans' cells, B cells and activated monocytes) are structurally homologous to major histocompatibility complex (MHC) class I and class II molecules. CD1b and CD1c have been shown to present nonpeptide bacterial antigens to T cells. We hypothesized that CD1 molecules may also be involved in the presentation of bacterial protein antigens. Human peripheral blood mononuclear cells (PBMC) were exposed to two medically important proteins, tetanus toxoid (TT) and purified protein derivative (PPD), with and without murine monoclonal antibodies (MoAbs) specific for CD1a, CD1b and CD1c. All the MoAbs substantially inhibited the proliferative responses of PBMC to TT and PPD. Simultaneous interaction of CD1 and MHC class II molecules was even more inhibitory to these antigen-specific proliferative responses. In contrast, neither mixed lymphocyte reaction nor superantigen and mitogenic responses were affected by CD1-specific antibodies, indicating a certain restriction pattern in antigen presentation. Our findings suggest that, besides MHC class I and II molecules, there is a family of nonpolymorphic cell surface molecules that is able to present certain bacterial protein antigens to T cells.

Antibodies, Monoclonal↗
PubMed1983

[Single-cell bacterial protein in the mixed feeds for early weaned piglets].

An experiment was carried out with a total of 21 hybrid Camborough pigs divided into three groups--group I, controls; group II, with 4 per cent of single-cell protein in the feed; and group III, with 8 per cent of such protein in the feed. The rations were balanced in terms of the basic feedstuffs. The pigs were kept under observation up to the age of 90 days. Three animals were periodically killed each time for investigation. Studied was the content of the total thiamine in the liver and the incorporation of the labelled 35s-thiamine in the jejunum. A histologic examination was also carried out of the jejunal mucosa and the liver. It was established that the inclusion of single-cell bacterial protein into the ration produced a positive effect on the total thiamine content of the liver. The group that was offered 8 per cent of this protein source showed reduced level of 35s-thiamine incorporation in the jejunum. Histologically, there were shortening and thickening of the intestinal villi along with signs of protein dystrophy in the liver epithelial cells in the case of animals given single-cell bacterial protein with the feed.

Animal Feed↗
PubMed2000

Sites of digestion and bacterial protein synthesis in dairy heifers fed fresh oats with or without corn or barley grain.

Six Holstein-Friesian heifers fitted with ruminal, duodenal, and ileal cannulas were used in a replicated 3x3 Latin square to study the effects of partial replacement [1:1 dry matter (DM) basis] of fresh winter oats (WO) by ground corn (C) or barley (B) on digestion and bacterial protein synthesis. Supplemented diets contained 24% starch, and all diets were fed indoors at 2.5% of body weight (DM basis). Ruminal and total tract digestibilities of organic matter and neutral detergent fiber were similar for all treatments. Ruminal and total tract starch digestibility was similar for C and B diets. Nitrogen intake was greater for WO than for supplemented diets. However, duodenal flows of nonammonia N and bacterial N did not differ among treatments. The efficiency of bacterial protein synthesis was similar for the three diets, suggesting that the fermentation of high quality fresh forage DM provided sufficient energy for the microorganisms in the rumen. Ruminal ammonia-N concentration was greater for WO than for supplemented diets, and for C than for B diet. Ruminal fluid pH and concentrations of total volatile fatty acid were not different among diets, but concentration of acetate was higher and that of propionate was lower for WO than for supplemented diets and for C than for B diet. Supplementation of WO with barley rather than with corn decreased C2:C3 ratio without affecting fiber digestion. Supplements increased N utilization relative to N intake but did not increase duodenal nonammonia N flow.

Ammonia↗