Effect Of Bacterial Products Research Articles

The effect of bacterial products and mineral fertilizers on growth and productivity of Brassica juncea Czern

The paper reports the results of field experiments that analyzed changes in growth indicators and productivity of Sarepta mustard (Brassica juncea Czern.) of the Start variety (k-4259) in response to inoculation and increasing doses of mineral nitrogen. Morphometric parameters and productivity of dry mass were measured during the stage of harvesting maturity, i.e., the full flowering stage. The seeds were inoculated with the following bacterial products: Agrofil (Agrobacterium radiobacter, strain 10), Mizorin (Arthrobacter mysorens, strain 7), Mobilin (Pseudomonas fluorescens, strain PG-5), and Flavobakterin (Flavobacterium sp., strain 30). The amount of nitrogen ranged from N30 to N120. It was enhanced with the application of PK at the rate of 60 kg/ha. The experiments showed that the application of bacterial products and increasing doses of mineral nitrogen has a stimulating effect on plants. The fertilizer formulation N120P60K60 and rhizobacteria strains Flavobacterium sp., strain 30, and Pseudomonas fluorescens, strain PG-5, proved to be the most effective. The obtained data were roughly consistent with the application of N90 and N120. The use of mineral fertilizers resulted in the highest productivity of dry shoot mass.

Signature Motifs Identify an Acinetobacter Cif Virulence Factor with Epoxide Hydrolase Activity

Endocytic recycling of the cystic fibrosis transmembrane conductance regulator (CFTR) is blocked by the CFTR inhibitory factor (Cif). Originally discovered in Pseudomonas aeruginosa, Cif is a secreted epoxide hydrolase that is transcriptionally regulated by CifR, an epoxide-sensitive repressor. In this report, we investigate a homologous protein found in strains of the emerging nosocomial pathogens Acinetobacter nosocomialis and Acinetobacter baumannii ("aCif"). Like Cif, aCif is an epoxide hydrolase that carries an N-terminal secretion signal and can be purified from culture supernatants. When applied directly to polarized airway epithelial cells, mature aCif triggers a reduction in CFTR abundance at the apical membrane. Biochemical and crystallographic studies reveal a dimeric assembly with a stereochemically conserved active site, confirming our motif-based identification of candidate Cif-like pathogenic EH sequences. Furthermore, cif expression is transcriptionally repressed by a CifR homolog ("aCifR") and is induced in the presence of epoxides. Overall, this Acinetobacter protein recapitulates the essential attributes of the Pseudomonas Cif system and thus may facilitate airway colonization in nosocomial lung infections.

Breaking Tolerance in Transgenic Mice Expressing the Human TSH Receptor A-Subunit: Thyroiditis, Epitope Spreading and Adjuvant as a ‘Double Edged Sword’

Transgenic mice with the human thyrotropin-receptor (TSHR) A-subunit targeted to the thyroid are tolerant of the transgene. In transgenics that express low A-subunit levels (Lo-expressors), regulatory T cell (Treg) depletion using anti-CD25 before immunization with adenovirus encoding the A-subunit (A-sub-Ad) breaks tolerance, inducing extensive thyroid lymphocytic infiltration, thyroid damage and antibody spreading to other thyroid proteins. In contrast, no thyroiditis develops in Hi-expressor transgenics or wild-type mice. Our present goal was to determine if thyroiditis could be induced in Hi-expressor transgenics using a more potent immunization protocol: Treg depletion, priming with Complete Freund's Adjuvant (CFA) + A-subunit protein and further Treg depletions before two boosts with A-sub-Ad. As controls, anti-CD25 treated Hi- and Lo-expressors and wild-type mice were primed with CFA+ mouse thyroglobulin (Tg) or CFA alone before A-sub-Ad boosting. Thyroiditis developed after CFA+A-subunit protein or Tg and A-sub-Ad boosting in Lo-expressor transgenics but Hi- expressors (and wild-type mice) were resistant to thyroiditis induction. Importantly, in Lo-expressors, thyroiditis was associated with the development of antibodies to the mouse TSHR downstream of the A-subunit. Unexpectedly, we observed that the effect of bacterial products on the immune system is a “double-edged sword”. On the one hand, priming with CFA (mycobacteria emulsified in oil) plus A-subunit protein broke tolerance to the A-subunit in Hi-expressor transgenics leading to high TSHR antibody levels. On the other hand, prior treatment with CFA in the absence of A-subunit protein inhibited responses to subsequent immunization with A-sub-Ad. Consequently, adjuvant activity arising in vivo after bacterial infections combined with a protein autoantigen can break self-tolerance but in the absence of the autoantigen, adjuvant activity can inhibit the induction of immunity to autoantigens (like the TSHR) displaying strong self-tolerance.

Growth‐promoting Effect of Bacterial Products from Clostridium perfringens on Human Keratinocytes

Wound healing substance (WHS) from cultured Clostridium perfringens has been reported to be effective in the treatment of wounds. The effects of WHS, now named SNK-863, on proliferation and differentiation of human keratinocytes were examined. The characteristics of WHS are as follows: 1) WHS stimulates human keratinocyte growth and DNA synthesis; 2) WHS and EGF show some additive effects on human keratinocyte growth; 3) WHS does not interfere with the binding of EGF to its receptor; 4) WHS does not counteract the growth inhibitory effects of TGF-beta or vitamin D3 on human keratinocytes; 5) WHS has no significant effect on human keratinocyte differentiation. These results indicate that the growth-promoting effect of WHS on keratinocytes may contribute to the treatment of wound healing.

Effect of bacterial products on neutrophil chemotaxis

This chapter addresses the complex molecular, biochemical, and cellular events through which bacterial substances influence the chemotactic responsiveness of professional phagocytes. Chemotactic factors are defined as those molecules that induce directional movement of cells exposed to a gradient of the agent. Most chemoattractants activate numerous other cellular functions or pathways, including glycolysis, oxygen consumption, exocytosis, and nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase activation and superoxide production. These various pathways exhibit differential responsiveness that depends on not only the nature of the chemotactic factor but its concentration. It is important to keep in mind that the chemotactic response does not occur in isolation but is part of a complex stimulus–response coupling system. It is also suggested that the primary role of chemoattractants in vivo is not to effect directed movement but rather to induce increased locomotion (chemokinesis).The techniques used to study chemotaxis described are micropore filter and under agarose. The chapter examines the direct influence of various bacteria and bacterial products on the response of host leukocytes to the chemoattractants.

Effect of bacterial products on neutrophil migration in vitro.

Chronic bronchial inflammation is associated with migration of large numbers of granulocytes into the bronchial tree. A study was designed to find out whether products of bacteria commonly isolated in chronic bronchial infection stimulate neutrophil migration in vitro. Neutrophils from healthy donors were studied by a modified Boyden chamber technique. Bacterial culture filtrates stimulated neutrophil migration over a wide dilution range and the chemotactic activity was heat stable. Culture filtrates derived from Pseudomonas aeruginosa, Streptococcus pneumoniae, and Haemophilus influenzae were significantly chemokinetic and directionally chemotactic, whereas filtrates from Staphylococcus aureus were only chemotactic. Gel filtration of S aureus and P aeruginosa culture filtrates yielded high, medium, and low molecular weight fractions showing chemotactic activity. S pneumoniae and H influenzae yielded fractions with only low molecular weight chemotactic activity. Neutrophil chemotactic responses, occurring in response to all bacterial species tested, appear to represent a defence mechanism by the host. Chemoattractant activity may, however, contribute to bronchial damage mediated by products released from continuously attracted, activated neutrophils.

The effect of bacterial products on human fibroblast and keratinocyte detachment and viability

An in vitro model has been developed to study the effect of soluble bacterial products on the viability and detachment of skin cell types utilized cultured grafts. Microbial products prepared from clinical isolates of bacterial species which most commonly colonize burn lesions showed marked variation in their ability to detach and kill both keratinocytes and fibroblasts. All three isolates of Acinetobacter spp. tested were effective in causing detachment and death of keratinocytes and fibroblasts, whereas Escherichia coli, Proteus mirabilis and Enterobacter spp. tested had little, or no, effect on detachment or viability for either skin cell type. Four Staphylococcus aureus isolates elicited variable strain-dependent results with regard to detachment and viability. One isolate possessed activity specific for keratinocyte detachment and death. These results indicate the possible undesirable effects such bacterial species may have on graft success in colonized burn wounds.

The effect of bacterial products on ciliary function.

Mucociliary clearance protects the respiratory epithelium against inhaled particles. There is in vitro evidence that some bacteria produce factors that cause ciliary slowing, dyskinesia, and stasis. These changes may predominantly affect ciliary function alone or be associated with epithelial disruption and cell death. Some factors act immediately, while others can take up to a number of days to achieve effect. It is postulated that rapidly acting factors may be involved during bacterial colonization, allowing the bacterium time (by slowing clearance) to penetrate the mucociliary barrier and reach putative receptors on the epithelial surface. The compounds might similarly facilitate contiguous spread through the bronchial tree and augment the tissue damage caused by the host inflammatory response during chronic bronchial sepsis. Future work should define more clearly the in vivo significance of the largely in vitro observations made to date.

The effect of uropathogenic bacteria on ureteral motility.

The effect of bacterial products of various strains obtained from patients with urinary tract infections was tested on peristalsis of sheep ureteral rings. In 55-70% spontaneous rhythmic contractions were inhibited by addition of small amounts of growth supernatants from Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The isolates were also tested on mesenteric artery ring preparations. In these vessels the isolates induced tonic contractions, particularly when the vessel had been depolarised and precontracted with a 40 mM KCl solution. This response is characteristic of a calcium ionophore, known to occur in some bacterial toxins. The active principle of the bacterial ureteroplegic factor (BUF) is heat sensitive and distinct from endotoxins which speed up peristalsis. It is suggested that the ureteroplegic action depends on an exotoxin with ionophoric properties.

Effect of bacterial products on human ciliary function in vitro.

Ciliary activity protects the respiratory tract against inhaled particles, including bacteria, by transporting them trapped in mucus towards the pharynx. We have studied the effect of bacteria (Haemophilus influenzae, Staphylococcus aureus, and Pseudomonas aeruginosa) on human nasal cilia, measuring their in vitro ciliary beat frequency by a photometric technique. Supernatant fluids were obtained from 18 hour broth cultures by centrifugation alone, by filtration, and by lysis. Supernatants obtained from Ps aeruginosa and H influenzae caused a significantly lower ciliary beat frequency than controls (broth alone). Slowed cilia were dyskinetic and at times of maximal slowing ciliostasis occurred in some areas of the epithelium. A dose related effect was demonstrated. Abrogation of cilioinhibitory properties was achieved by heating the lysate to 56 degrees C for 30 minutes and by allowing the filtrate to stand at 37 degrees C for 120 minutes. Staphylococcal products were not cilioinhibitory. It is concluded that Ps aeruginosa and H influenzae release a factor (or factors) which causes slowing of human nasal cilia in vitro. The role of this factor in the pathogenesis of infection is discussed.

Periodontal Status of Patients With Reduced Immunocapacity

The periodontal status of patients with reduced immunocapacity was assessed. Gingival inflammation, periodontal destruction, and plaque accumulation were compared in three groups--renal transplant patients, dialysis patients, and normal individuals. The levels of all parameters were similar in the three groups indicating that immunosuppression does not affect the clinical appearance of periodontal disease when measurements are made in a single examination. In the transplant group, however, there is a lack of correlation between P.I. and G.I. and between P.I. and P.D.I., indicating a dissociation between plaque accumulation and the tissue response. Long-term longitudinal studies of periodontal disease in such patients are needed in order to obtain more meaningful information on the role of the immune system in affecting the rate of periodontal destruction. This study suggests that nonimmune mechanisms such as the direct effect of bacterial products on supporting tissues can account for at least some of the clinical manifestations of periodontal disease.

Brain Carbohydrate Metabolism during Experimental Haemophilus influenzae meningitis

Five-day-old infant rats which acquire Haemophilus influenzae b bacteremia and meningitis after intranasal inoculation have a transient depression in weight gain (2 days), but then continue to grow at the same rate as strain U--11 inoculated controls. Brain lactate, glucose, and glycogen concentrations increase during the first 5 days of disease in infected animals. The increase in brain glycogen can be accounted for by an influx of glycogen containing polymorphonuclear leukocytes. The increased concentrations of glucose and lactate were found not to be due to a change in brain weight to dry weight ratio or the volume of entrapped blood. The mean cerebrospinal fluid (CSF) glucose concentration was higher in animals with meningitis (2.7 mM) in comparison to U-11 inoculated controls (1.8 mM). This increase in brain and CSF glucose concentration appeared secondary to an increased brain uptake of hexoses as manifested by an increased [3H]mannitol uptake. Brain lactate accumulation was not explicable from the data available. There was no evidence of cerebral cortical cellular damage because in vitro oxygen uptake and lactate production were equivalent in control and meningitic animals. The ability of the infant rat brain to maintain cerebral adenosine triphosphate (ATP) content in menigitis and the failure of CSF glucose concentration to decrease might be a reflection of the importance of alternative oxidative substrate (e.g., beta-hydroxybutyrate) to the cerebral metabolism of the developing rat brain.

Effect of bacterial products on inflammatory reactions in the dental pulp

Culture filtrates (extracellular components) and material obtained from disintegrated cells (intracellular components) of cultured plaque bacteria were studied for their capacity to induce inflammatory reactions in the dental pulp. Class V cavities were prepared on the buccal surface of 94 teeth: 42 test and 52 control teeth in six adult monkeys. lyophilized bacterial components were sealed into the test cavities either alone or following an 8-h topical application of a solution of the same components in phosphate-buffered saline (PBS). Culture medium and PBS were applied in two sets of control cavities. A third set was restored with zinc oxide-eugenol cement. The animals were killed 32 h after the initiation of the experiment and the pulps were examined histologically. Teeth treated trophil leukocytes in the area of the pulp subjacent to the cut dentin tubules. Abscess formation was frequently found. The severe reactions which developed were independent of differences between individual animals and differences in thickness of the remaining dentin. The controls showed damage to the odontoblasts but little or no neutrophil infiltration. The findings confirm that products of bacteria applied to exposed dentin initiate inflammatory reactions in the dental pulp.

The effect of bacterial products on synovial fibroblast function: hypermetabolic changes induced by endotoxin.

The effects of bacterial products on selected synovial fibroblast functions were studied. Extracts of commonly encountered microorganisms were prepared by sonic or mechanical disruption. "Purified" endotoxins were prepared from selected organisms, and in some cases were purchased commercially. Normal fibroblasts were derived from synovial connective tissue obtained from amputations or arthrotomy. The cells were grown as a monolayer on glass and were nourished by a semisynthetic nutrient medium. Extracts of Gram-negative bacteria, applied to fibroblast cultures, markedly increased hyaluronic acid production, glucose utilization, and lactate output. Treatment of the extracts with heat at 100 degrees C for (1/2) hr decreased their effectiveness by approximately 40%. Purified Gram-negative bacterial endotoxin stimulated synovial fibroblasts to an extent comparable to that caused by heat-treated whole extracts. The lipid moiety of the endotoxin molecule appeared to account for much of the stimulatory activity of the endotoxin. Extracts of commonly encountered Gram-positive cocci, yeast, and Mycoplasma had no stimulating capabilities. Corynebacterial extracts, however, had definite stimulating potential. Endotoxin-synovial cell interaction experiments demonstrated that endotoxin was bound to fibroblasts. Reassay of the endotoxin after extraction from the cells showed that it retained its stimulatory potential. The metabolic phenomena stimulated by bacterial products duplicate the major known actions of connective tissue-activating peptide (CTAP). The observations made in this study suggest that bacterial products may participate in a fundamental way in the activation process, and indicate a possible role for bacterial products in synovial inflammation in humans.

A Bacteriological Study of Mouse Tumors: II. Bacterial Immunity and Tumor Growth; Effect of Bacterial Products on Tumors

The effect of B. danysz on the Ehrlich mouse carcinoma was described in a previous report (1936). Hyperemia and other changes, which were interpreted as being of a regressive nature, were observed in the tumors following intratumoral injection of this highly pathogenic microorganism. The experiments to be described in this paper deal with the attempt to immunize mice against infection with B. danysz by inoculation of a vaccine of that organism, the study of tumor transplants in these animals, and the reaction of the animals as well as the tumors to the injection of virulent B. danysz as compared to that of immunized but non-tumor-bearing animals. The effect of intraperitoneal injections of toxin and heat-killed cultures of B. danysz on the Ehrlich mouse carcinoma was also studied. Torrey and Kahn (1927), during their studies of the effect of proteolytic anaerobes on tumors, attempted to immunize rats actively and passively against B. histolyticus . They then noted the effect of this microorganism on the Flexner-Jobling carcinoma which had been transplanted in these animals. The immunization had no effect on tumor growth, but subsequent injection of cultures of B. histolyticus directly into the tumor apparently caused regression in a number of instances. However, this procedure was not more effective than the injection of B. histolyticus into the tumors of non-treated animals. Lewin (1928) reported that non-specific protein therapy increased the resistance of animals to tumors, for transplants grew poorly in rats and mice that had been subjected to such treatment previous to transplantation. Uhlenhuth (1937), however, found that non-specific protein therapy had no effect on the course of transplanted tumors in mice or rats.

The Effect of Bacterial Products on Amoebic Growth

ABSTRACT The interrelationships that exist between various groups of Protozoa in nature and the bacteria which occur in the same environments are undoubtedly of more than academic interest. This is especially the case perhaps in soil, where both types of organisms are present in very large numbers, and where a marked degree of activity is evidenced by the continual fluctuation to which these numbers are subject. The food relationships of one member of the soil population, the amoeba Hartmanella hyalina, was described in a previous paper (2), where it was shown that certain kinds of bacteria afforded a more efficient food supply than others as judged by the reproductive rate of the amoeba. A priori this might have been due to the fact that the bacteria giving a high reproductive rate to the amoebae were of greater food value than the others ; or that the by-products formed by the less valuable bacterium in the course of growth were deleterious in their effects; but preliminary experiments indicated that for the species of bacteria concerned it was a true food value effect and not one caused by the presence of any by-products.