Streptococci and lactococci synthesize large amounts of HPr(Ser-P)(His~P)

2008 ◽  
Vol 54 (11) ◽  
pp. 941-949 ◽  
Author(s):  
Denis J. Roy ◽  
Israël Casabon ◽  
Katy Vaillancourt ◽  
Jonathan L. Huot ◽  
Christian Vadeboncoeur
Keyword(s):  
Intracellular Ph ◽  
Sugar Transport ◽  
The Other ◽  
Acidic Ph ◽  
Streptococcus Salivarius ◽  
Gram Positive Bacteria ◽  
Streptococcal Species ◽  
Enzyme I ◽  
Phosphotransferase Transport System

HPr is a protein of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS). In gram-positive bacteria, HPr can be phosphorylated on Ser-46 by the kinase/phosphorylase HprK/P and on His-15 by phospho-enzyme I (EI~P) of the PTS. In vitro studies with purified HPrs from Bacillus subtilis , Enterococcus faecalis , and Streptococcus salivarius have indicated that the phosphorylation of one residue impedes the phosphorylation of the other. However, a recent study showed that while the rate of Streptococcus salivarius HPr phosphorylation by EI~P is reduced at acidic pH, the phosphorylation of HPr(Ser-P) by EI~P, generating HPr(Ser-P)(His~P), is stimulated. This suggests that HPr(Ser-P)(His~P) synthesis may occur in acidogenic bacteria unable to maintain their intracellular pH near neutrality. Consistent with this hypothesis, significant amounts of HPr(Ser-P)(His~P) have been detected in some streptococci. The present study was aimed at determining whether the capacity to synthesize HPr(Ser-P)(His~P) is common to streptococcal species, as well as to lactococci, which are also unable to maintain their intracellular pH near neutrality in response to a decrease in extracellular pH. Our results indicated that unlike Staphylococcus aureus, B. subtilis, and E. faecalis, all the streptococcal and lactococcal species tested were able to synthesize large amounts of HPr(Ser-P)(His~P) during growth. We also showed that Streptococcus salivarius IIABLMan, a protein involved in sugar transport by the PTS, could be efficiently phosphorylated by HPr(Ser-P)(His~P).

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

A common pathway for sugar transport in hamster intestine

1961 ◽  
Vol 200 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Charles R. Jorgensen ◽  
Bernard R. Landau ◽  
T. Hastings Wilson
Keyword(s):  
Small Intestine ◽  
Transport Mechanism ◽  
Sugar Transport ◽  
The Other ◽  
Common Pathway ◽  
In Vitro Method ◽  
Single Segment ◽  
Other Hand

The competition between different sugars for the transport mechanism of hamster small intestine was tested with an in vitro method which allowed the use of a single segment of intestine for both control and experimental periods. The transport of the test sugar d-galactose was inhibited by other sugars known to be actively absorbed by the intestine; namely, d-glucose, α-methyl-d-glucoside, i-deoxy-d-glucose, 6-deoxy-d-glucose and 3-o-methyl-d-glucose. On the other hand d-mannose and d-xylose, two sugars not actively transported, did not inhibit d-galactose absorption. In addition, sugars known to be actively absorbed produced an inhibition of transport of d-glucose and 6-deoxy-d-glucose when these were selected as test sugars. The results of these experiments are consistent with the view that all transported sugars compete for a common pathway in hamster intestine. Various hypotheses of sugar transport are discussed in light of the present data.

scholarly journals In vitro and in vivo antibacterial activities of CS-940, a new 6-fluoro-8-difluoromethoxy quinolone.

1996 ◽  
Vol 40 (5) ◽  
pp. 1201-1207 ◽  
Author(s):  
N Masuda ◽  
Y Takahashi ◽  
M Otsuki ◽  
E Ibuki ◽  
H Miyoshi ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Oral Treatment ◽  
Horse Serum ◽  
Antibacterial Activities ◽  
Inoculum Size ◽  
The Other ◽  
Gram Positive Bacteria ◽  
Systemic Infections

The in vitro and in vivo activities of CS-940, a new 6-fluoro-8-difluoromethoxy quinolone, were compared with those of ciprofloxacin, tosufloxacin, sparfloxacin, and levofloxacin. The in vitro activity of CS-940 against gram-positive bacteria was nearly equal to or greater than those of the other quinolones tested. In particular, CS-940 was two to eight times more active against methicillin-resistant Staphylococcus aureus than the other quinolones, at the MIC at which 90% of the clinical isolates are inhibited. Against gram-negative bacteria, the activity of CS-940 was comparable to or greater than those of tosufloxacin, sparfloxacin, and levofloxacin, while it was lower than that of ciprofloxacin. The activity of CS-940 was largely unaffected by medium, inoculum size, or the addition of horse serum, but it was decreased under acidic conditions, as was also seen with the other quinolones tested. CS-940 showed potent bactericidal activity against S. aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. In oral treatment of mouse systemic infections caused by S. aureus, Streptococcus pneumoniae, Streptococcus pyogenes, E. coli, K. pneumoniae, Serratia marcescens, and P. aeruginosa, CS-940 was more effective than ciprofloxacin, sparfloxacin, and levofloxacin against all strains tested. Against experimental pneumonia with K. pneumoniae in mice, CS-940 was the most effective of all the quinolones tested. These results suggest that CS-940 may be effective in the therapy of various bacterial infections.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW286, a New Fluoronaphthyridone Antibiotic

2002 ◽  
Vol 46 (9) ◽  
pp. 3071-3074 ◽  
Author(s):  
Hee-Jeong Yun ◽  
Yu-Hong Min ◽  
Jung-A Lim ◽  
Jin-Wook Kang ◽  
So-Young Kim ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Systemic Infection ◽  
Antibacterial Activities ◽  
The Other ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT The in vitro and in vivo activities of DW286, a novel fluoronaphthyridone with potent antibacterial activity, were compared with those of ciprofloxacin, gemifloxacin, sparfloxacin, and trovafloxacin. Against gram-positive bacteria, such as Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Enterococcus faecalis, the in vitro activity of DW286 was stronger than that of any other reference antibiotic. Against gram-negative bacteria, the activity of DW286 was similar to those of trovafloxacin and gemifloxacin but was weaker than that of ciprofloxacin. In a mouse systemic infection caused by three S. aureus strains, including methicillin-resistant S. aureus and quinolone-resistant S. aureus (QRSA), DW286 demonstrated the most potent activity, as found in vitro. Specially, DW286 is ≥8-fold more active against QRSA than the other fluoroquinolones. And the 50% protective doses for DW286 were correspondent with the in vitro activities.

scholarly journals Phosphorylation of Streptococcus salivarius Lactose Permease (LacS) by HPr(His∼P) and HPr(Ser-P)(His∼P) and Effects on Growth

2003 ◽  
Vol 185 (23) ◽  
pp. 6764-6772 ◽  
Author(s):  
Christian Lessard ◽  
Armelle Cochu ◽  
Jean-Dominique Lemay ◽  
Denis Roy ◽  
Katy Vaillancourt ◽  
...  
Keyword(s):  
Streptococcus Thermophilus ◽  
Lactose Permease ◽  
Streptococcus Salivarius ◽  
Phosphorylated Form ◽  
Generation Times ◽  
Related Organism ◽  
Oral Bacterium ◽  
Mutant Strains ◽  
Enzyme I ◽  
Phosphotransferase Transport System

ABSTRACT The oral bacterium Streptococcus salivarius takes up lactose via a transporter called LacS that shares 95% identity with the LacS from Streptococcus thermophilus, a phylogenetically closely related organism. S. thermophilus releases galactose into the medium during growth on lactose. Expulsion of galactose is mediated via LacS and stimulated by phosphorylation of the transporter by HPr(His∼P), a phosphocarrier of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS). Unlike S. thermophilus, S. salivarius grew on lactose without expelling galactose and took up galactose and lactose concomitantly when it is grown in a medium containing both sugars. Analysis of the C-terminal end of S. salivarius LacS revealed a IIA-like domain (IIALacS) almost identical to the IIA domain of S. thermophilus LacS. Experiments performed with purified proteins showed that S. salivarius IIALacS was reversibly phosphorylated on a histidine residue at position 552 not only by HPr(His∼P) but also by HPr(Ser-P)(His∼P), a doubly phosphorylated form of HPr present in large amounts in rapidly growing S. salivarius cells. Two other major S. salivarius PTS proteins, IIABL Man and IIABH Man, were unable to phosphorylate IIALacS. The effect of LacS phosphorylation on growth was studied with strain G71, an S. salivarius enzyme I-negative mutant that cannot synthesize HPr(His∼P) or HPr(Ser-P)(His∼P). These results indicated that (i) the wild-type and mutant strains had identical generation times on lactose, (ii) neither strain expelled galactose during growth on lactose, (iii) both strains metabolized lactose and galactose concomitantly when grown in a medium containing both sugars, and (iv) the growth of the mutant was slightly reduced on galactose.

scholarly journals IN VITRO ANTIMICROBIAL ACTIVITY OF CARVACROL AGAINST SHRIMP PATHOGENS AND ITS USE AS FEED ADDITIVE FOR THE PACIFIC WHITE SHRIMP

2021 ◽  
Vol 47 ◽  
pp. e645
Author(s):  
Jaqueline da Rosa COELHO ◽  
Karolina Victória ROSA ◽  
Jamilly Sousa ROCHA ◽  
Norha Constanza Bolívar RAMÍREZ ◽  
Marcelo MARASCHIN ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Vibrio Harveyi ◽  
Pacific White Shrimp ◽  
The Other ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Vitro Effect

This study aimed to evaluate the in vitro effect of carvacrol on different microorganisms of importance in shrimp farming, as well as its in vivo effect on zootechnical, immunological and microbiological performance, as well as resistance, of Litopenaeus vannamei challenged with Vibrio parahaemolyticus. In particular, the antimicrobial activity of carvacrol was evaluated in vitro by analysis of the minimum inhibitory concentration (MIC) and by agar diffusion disc with Gram-negative and Gram-positive bacteria. The in vivo experiment was conducted using different concentrations of carvacrol (1, 3, 4 and 6 mg mL-1) added to shrimp feed, together with a control diet without carvacrol. After four weeks, zootechnical, immunological and microbiological parameters, as well as resistance, of animals challenged with V. parahaemolyticus were evaluated. The MIC of Vibrio alginolyticus and Vibrio harveyi was 0.078 mg mL-1, while for the other bacteria, it was 0.156 mg mL-1 of carvacrol. The greatest halos of inhibition were observed in V. parahaemolyticus and Vibrio harveyi with significant differences demonstrated for the other microorganisms, except Escherichia coli. The in vivo results showed no significant differences among treatments. In conclusion, the antimicrobial activity of carvacrol was confirmed with Gram-negative and Gram-positive bacteria, and it is suggested that its antimicrobial potential is more effective against Vibrio spp. However, the concentrations of carvacrol used in vivo did not affect the parameters evaluated.

scholarly journals Diversity of Streptococcus salivarius ptsH Mutants That Can Be Isolated in the Presence of 2-Deoxyglucose and Galactose and Characterization of Two Mutants Synthesizing Reduced Levels of HPr, a Phosphocarrier of the Phosphoenolpyruvate:Sugar Phosphotransferase System

2001 ◽  
Vol 183 (17) ◽  
pp. 5145-5154 ◽  
Author(s):  
Suzanne Thomas ◽  
Denis Brochu ◽  
Christian Vadeboncoeur
Keyword(s):  
Solid Medium ◽  
Growth Conditions ◽  
Streptococcus Salivarius ◽  
Phosphotransferase System ◽  
Physiological Functions ◽  
Generation Times ◽  
Shine Dalgarno Sequence ◽  
Enzyme I ◽  
Phosphotransferase Transport System

ABSTRACT In streptococci, HPr, a phosphocarrier of the phosphoenolpyruvate:sugar phosphotransferase transport system (PTS), undergoes multiple posttranslational chemical modifications resulting in the formation of HPr(His∼P), HPr(Ser-P), and HPr(Ser-P)(His∼P), whose cellular concentrations vary with growth conditions. Distinct physiological functions are associated with specific forms of HPr. We do not know, however, the cellular thresholds below which these forms become unable to fulfill their functions and to what extent modifications in the cellular concentrations of the different forms of HPr modify cellular physiology. In this study, we present a glimpse of the diversity of Streptococcus salivarius ptsH mutants that can be isolated by positive selection on a solid medium containing 2-deoxyglucose and galactose and identify 13 amino acids that are essential for HPr to properly accomplish its physiological functions. We also report the characterization of two S. salivariusmutants that produced approximately two- and threefoldless HPr and enzyme I (EI) respectively. The data indicated that (i) a reduction in the synthesis of HPr due to a mutation in the Shine-Dalgarno sequence of ptsH reduced ptsIexpression; (ii) a threefold reduction in EI and HPr cellular levels did not affect PTS transport capacity; (iii) a twofold reduction in HPr synthesis was sufficient to reduce the rate at which cells metabolized PTS sugars, increase generation times on PTS sugars and to a lesser extent on non-PTS sugars, and impede the exclusion of non-PTS sugars by PTS sugars; (iv) a threefold reduction in HPr synthesis caused a strong derepression of the genes coding for α-galactosidase, β-galactosidase, and galactokinase when the cells were grown at the expense of a PTS sugar but did not affect the synthesis of α-galactosidase when cells were grown at the expense of lactose, a noninducing non-PTS sugar; and (v) no correlation was found between the magnitude of enzyme derepression and the cellular levels of HPr(Ser-P).

Cytochemical Studies of Cell Wall Biosynthesis in Staphylococcus Aureus

1972 ◽  
Vol 30 ◽  
pp. 328-329
Author(s):  
Masaatsu Koike ◽  
Koichi Nakashima ◽  
Kyoko Iida
Keyword(s):  
Staphylococcus Aureus ◽  
Periodate Oxidation ◽  
Early Time ◽  
The Other ◽  
Penicillin G ◽  
Cell Wall Biosynthesis ◽  
Septal Wall ◽  
Peptidoglycan Biosynthesis ◽  
Gram Positive Bacteria ◽  
Cross Linkage

Penicillin exerts the activity to inhibit the peptide cross linkage between each polysaccharide backbone at the final stage of wall-peptidoglycan biosynthesis of bacteria. Morphologically, alterations of the septal wall and mesosome in gram-positive bacteria, which were occurred in early time after treatment with penicillin, have been observed. In this experiment, these alterations were cytochemically investigated by means of silver-methenamine staining after periodate oxidation, which is applied for detection of localization of wall mucopolysaccharide.Staphylococcus aureus strain 209P treated with 100 u/ml of penicillin G was divided into two aliquotes. One was fixed by Kellenberger-Ryter's OSO4 fixative at 30, 60 and 120 min after addition of the antibiotic, dehydrated through alcohol series, and embedded in Epon 812 (Specimen A). The other was fixed by 21 glutaraldehyde, dehydrated through glycolmethacrylate series and embedded in glycolmethacrylate mixture, according to Bernhard's method (Specimen B).

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

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