The enzymatic activity of phosphoglycerate mutase from gram-positive endospore-forming bacteria requires Mn2+ and is pH sensitive

1998 ◽  
Vol 44 (8) ◽  
pp. 759-767 ◽  
Author(s):  
Monica Chander ◽  
Barbara Setlow ◽  
Peter Setlow
Keyword(s):  
Enzymatic Activity ◽  
Micrococcus Luteus ◽  
Streptomyces Coelicolor ◽  
Ph Sensitive ◽  
Phosphoglycerate Mutase ◽  
Glyceric Acid ◽  
Ph Change ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Phosphoglyceric Acid

The enzymatic activity of phosphoglycerate mutase (Pgm) from three gram-positive endospore-forming bacteria (Bacillus subtilis, Clostridium perfringens, and Sporosarcina ureae) requires Mn2+ and is very sensitive to pH; at low concentrations of Mn2+, a pH change from 8 to 6 resulted in greater than 30- to 200-fold decreases in the activity of these Pgms. However, Pgm deactivation at pH 6 was reversed by shifting the enzyme to pH 7 or 8. Free Mn2+ was not directly involved in Pgm catalysis, although enzyme-bound Mn2+ may be involved. The rate of catalysis by Mn2+-containing Pgm was also slightly pH dependent, although the Km for 3-phosphoglyceric acid appeared to be the same at pH 6, 7, and 8. These findings suggest that Mn2+ binds to catalytically inactive Pgm and converts it to a catalytically competent form, and further, that pH influences the efficiency with which the enzyme binds Mn2+. The extreme pH sensitivity of the Mn2+-dependent Pgms supports a model in which this enzyme is inhibited during sporulation by acidification of the forespore, thus allowing accumulation of the spore's large depot of 3-phospho-glyceric acid. The activity of Pgm from two closely related gram-positive bacteria that do not form spores (Planococcus citreus and Staphylococcus saprophyticus) also requires Mn2+ and is pH sensitive. In contrast, the Pgm activities from two more distantly related non-endospore-forming gram-positive bacteria (Micrococcus luteus and Streptomyces coelicolor) are neither dependent on metal ions nor particularly sensitive to pH.Key words: Bacillus, Clostridium, Mn2+, phosphoglycerate mutase, sporulation.

scholarly journals Sarconesin II, a New Antimicrobial Peptide Isolated from Sarconesiopsis magellanica Excretions and Secretions

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2077 ◽  
Author(s):  
Andrea Díaz-Roa ◽  
Abraham Espinoza-Culupú ◽  
Orlando Torres-García ◽  
Monamaris M. Borges ◽  
Ivan N. Avino ◽  
...  
Keyword(s):  
Micrococcus Luteus ◽  
Multidrug Resistant ◽  
Peptide Sequence ◽  
Resistant Bacteria ◽  
Gram Positive ◽  
Antimicrobial Drugs ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Conserved Domain ◽  
Health Institutions

Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. Sarconesiopsis magellanica blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs). This study aims to identify and characterize a new S. magellanica AMP. RP-HPLC was used to fractionate ES, using C18 columns, and their antimicrobial activity was evaluated. The peptide sequence of the fraction collected at 43.7 min was determined by mass spectrometry (MS). Fluorescence and electronic microscopy were used to evaluate the mechanism of action. Toxicity was tested on HeLa cells and human erythrocytes; physicochemical properties were evaluated. The molecule in the ES was characterized as sarconesin II and it showed activity against Gram-negative (Escherichia coli MG1655, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa PA14) and Gram-positive (Staphylococcus aureus ATCC 29213, Micrococcus luteus A270) bacteria. The lowest minimum inhibitory concentration obtained was 1.9 μM for M. luteus A270; the AMP had no toxicity in any cells tested here and its action in bacterial membrane and DNA was confirmed. Sarconesin II was documented as a conserved domain of the ATP synthase protein belonging to the Fli-1 superfamily. The data reported here indicated that peptides could be alternative therapeutic candidates for use in infections against Gram-negative and Gram-positive bacteria and eventually as a new resource of compounds for combating multidrug-resistant bacteria.

scholarly journals 045 ANTIBIOTIC SUSCEPTIBILITY OF PLANT-ASSOCIATED BACTERIA

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 434c-434 ◽  
Author(s):  
Patricia M. Buckley ◽  
Barbara M. Reed
Keyword(s):  
Bacterial Growth ◽  
Infected Plant ◽  
Basic Information ◽  
Ph Change ◽  
Gram Positive ◽  
Associated Bacteria ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Antibiotic Susceptibilities ◽  
Microbial Contaminants

Most bacteria isolated from persistently contaminated micropropagated mint plants were Gram-negative rods identified as xanthomonads, pseudomonads, and agrobacteria based on their cultural characteristics. A few Gram-positive, non-sporeforming bacteria were also found. Inhibition of bacterial growth by gentamicin and streptomycin was greater at pH 6.5 and pH 7.5 than at pH 5.5. Inhibition by rifampicin and Timentin was less affected by pH change. Pseudomonads were uniformly resistant to Timentin at all pH's and at levels up to 1000 μg/ml. Streptomycin at 500 μg/ml was bactericidal for the pseudomonads and Gram-positive bacteria while 1000 μg/ml was required to kill xanthomonads and agrobacteria. Minimal bactericidal concentrations for gentamicin varied widely, even within groups, and ranged from 10 μg/ml to >80 μg/ml for agrobacteria. These results emphasize a need to acquire basic information about the identities and antibiotic susceptibilities of microbial contaminants before attempting treatment of infected plant cultures.

scholarly journals WhiA, a Protein of Unknown Function Conserved among Gram-Positive Bacteria, Is Essential for Sporulation inStreptomyces coelicolor A3(2)

2000 ◽  
Vol 182 (19) ◽  
pp. 5470-5478 ◽  
Author(s):  
J. A. Aínsa ◽  
N. J. Ryding ◽  
N. Hartley ◽  
K. C. Findlay ◽  
C. J. Bruton ◽  
...  
Keyword(s):  
Unknown Function ◽  
Streptomyces Coelicolor ◽  
Wild Type Allele ◽  
Wild Type ◽  
Phenotypic Analysis ◽  
Gram Positive ◽  
Gene Encoding ◽  
Gram Positive Bacteria ◽  
Aerial Hyphae ◽  
Conserved Genes

ABSTRACT The whiA sporulation gene of Streptomyces coelicolor A3(2), which plays a key role in switching aerial hyphae away from continued extension growth and toward sporulation septation, was cloned by complementation of whiA mutants. DNA sequencing of the wild-type allele and five whiAmutations verified that whiA is a gene encoding a protein with homologues in all gram-positive bacteria whose genome sequence is known, whether of high or low G+C content. No function has been attributed to any of these WhiA-like proteins. In most cases, as inS. coelicolor, the whiA-like gene is downstream of other conserved genes in an operon-like cluster. Phenotypic analysis of a constructed disruption mutant confirmed that whiA is essential for sporulation. whiA is transcribed from at least two promoters, the most downstream of which is located within the preceding gene and is strongly up-regulated when colonies are undergoing sporulation. The up-regulation depends on a functionalwhiA gene, suggesting positive autoregulation, although it is not known whether this is direct or indirect. Unlike the promoters of some other sporulation-regulatory genes, the whiApromoter does not depend on the sporulation-specific ς factor encoded by whiG.

scholarly journals Widespread Abundance of Functional Bacterial Amyloid in Mycolata and Other Gram-Positive Bacteria

2009 ◽  
Vol 75 (12) ◽  
pp. 4101-4110 ◽  
Author(s):  
Peter Bruun Jordal ◽  
Morten Simonsen Dueholm ◽  
Poul Larsen ◽  
Steen Vang Petersen ◽  
Jan Johannes Enghild ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Streptomyces Coelicolor ◽  
Bacterial Species ◽  
Gram Positive ◽  
Transmission Electron Microscopy Analysis ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Gordonia Amarae

ABSTRACT Until recently, extracellular functional bacterial amyloid (FuBA) has been detected and characterized in only a few bacterial species, including Escherichia coli, Salmonella, and the gram-positive organism Streptomyces coelicolor. Here we probed gram-positive bacteria with conformationally specific antibodies and revealed the existence of FuBA in 12 of 14 examined mycolata species, as well as six other distantly related species examined belonging to the phyla Actinobacteria and Firmicutes. Most of the bacteria produced extracellular fimbriae, sometimes copious amounts of them, and in two cases large extracellular fibrils were also produced. In three cases, FuBA was revealed only after extensive removal of extracellular material by saponification, indicating that there is integrated attachment within the cellular envelope. Spores of species in the genera Streptomyces, Bacillus, and Nocardia were all coated with amyloids. FuBA was purified from Gordonia amarae (from the cell envelope) and Geodermatophilus obscurus, and they had the morphology, tinctorial properties, and β-rich structure typical of amyloid. The presence of approximately 9-nm-wide amyloids in the cell envelope of G. amarae was visualized by transmission electron microscopy analysis. We conclude that amyloid is widespread among gram-positive bacteria and may in many species constitute a hitherto overlooked integral part of the spore and the cellular envelope.

scholarly journals Antibacterial efficacy of black seed honey in combination with penicillin and amoxiclav against gram-positive bacteria

2020 ◽  
Vol 6 (2) ◽  
pp. 61
Author(s):  
Rozely Hossain ◽  
M. S. Rahman ◽  
M. A. Rayhan ◽  
Kashfia Nawrin ◽  
Mohammad M. Billah ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Micrococcus Luteus ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Antibacterial Efficacy ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Black Seed ◽  
Microdilution Method ◽  
Zones Of Inhibition

<p class="abstract"><strong>Background:</strong> The emergence of antimicrobial resistance possesses a great threat for the existence of mankind. Antibiotics like penicillin and amoxiclav are at the brink of losing their efficacy entirely in exposure to resistant bacteria. Thus, the present study was aimed to find out the antibacterial efficacy of black seed honey as an alternative natural source which can act independently and boost the efficacy of standard drugs alongside.</p><p class="abstract"><strong>Methods:</strong> Penicillin, amoxiclav and black seed honey were first individually trailed against four gram-positive bacteria - <em>Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis </em>and<em> Micrococcus luteus</em>.<strong> </strong>Afterwards, penicillin and amoxiclav were used in combination with honey and compared the synergistic effects with their individual efficacy. Zones of inhibition from well diffusion method, percentage inhibition, minimum inhibitory and bactericidal concentrations by microdilution method were determined in the present study.  </p><p class="abstract"><strong>Results:</strong> Black seed honey alone demonstrated great inhibitory potential against <em>S. aureus </em>(9.7 mm), <em>S. epidermidis </em>(9.9 mm) and <em>M. luteus</em> (9.3 mm) in well diffusion method. Moreover, its combination with amoxiclav showed synergistic effect against all bacteria except <em>S. epidermidis</em>. However, its conjugation with penicillin was not able to produce any synergism as exhibited by zones of inhibition. The lowest concentration (1.56%) of honey applied individually or in combination in microdilution method found<strong> </strong>highly effective which established an inverse dose dependent relationship with efficacy.</p><p class="abstract"><strong>Conclusions:</strong> From the data it can be concluded that the black seed honey is a highly potent natural agent which can be utilized in antimicrobial therapy. However, further investigation is recommended to identify the responsible compound for such activity.</p>

scholarly journals Characterization of Actinomycetes Strains Isolated from the Intestinal Tract and Feces of the Larvae of the Longhorn Beetle Cerambyx welensii

2020 ◽  
Vol 8 (12) ◽  
pp. 2013
Author(s):  
Ramón I. Santamaría ◽  
Ana Martínez-Carrasco ◽  
Ricardo Sánchez de la Nieta ◽  
Luis M. Torres-Vila ◽  
Raúl Bonal ◽  
...  
Keyword(s):  
Natural Products ◽  
Intestinal Tract ◽  
Micrococcus Luteus ◽  
Hydrolytic Activity ◽  
Gram Positive ◽  
Genus Streptomyces ◽  
Gram Positive Bacteria ◽  
Longhorn Beetle ◽  
Cerambyx Welensii

Actinomycetes constitute a large group of Gram-positive bacteria present in different habitats. One of these habitats involves the association of these bacteria with insects. In this work, we have studied twenty-four actinomycetes strains isolated from the intestinal tract and feces from larvae of the xylophagous coleopteran Cerambyx welensii and have shown that seventeen strains present hydrolytic activity of some of the following substrates: cellulose, hemicellulose, starch and proteins. Fourteen of the isolates produce antimicrobial molecules against the Gram-positive bacteria Micrococcus luteus. Analysis of seven strains led us to identify the production of a wide number of compounds including streptanoate, alpiniamide A, alteramides A and B, coproporphyrin III, deferoxamine, demethylenenocardamine, dihydropicromycin, nocardamine, picromycin, surugamides A, B, C, D and E, tirandamycins A and B, and valinomycin. A significant number of other compounds, whose molecular formulae are not included in the Dictionary of Natural Products (DNP), were also present in the extracts analyzed, which opens up the possibility of identifying new active antibiotics. Molecular identification of ten of the isolated bacteria determined that six of them belong to the genus Streptomyces, two of them are included in the genus Amycolatopsis and two in the genus Nocardiopsis.

scholarly journals Synthesis, characterization and antibacterial screening of some Schiff bases derived from pyrazole and 4-amino antipyrine

2016 ◽  
Vol 45 (2) ◽  
pp. 201 ◽  
Author(s):  
Shipra Baluja ◽  
Sumitra Chanda
Keyword(s):  
Schiff Bases ◽  
Micrococcus Luteus ◽  
Dimethyl Formamide ◽  
Klebsiella Aerogenes ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Antibacterial Screening

Some Schiff bases of pyrazole and 4-amino antipyrine have been synthesized. The antibacterial screening of these synthesized compounds was done in dimethyl formamide against four Gram positive bacteria viz.Bacillus cereus, Staphylococcus aureus, Staphylococcus epidermidids and Micrococcus luteus, and three Gram negative bacteria viz. Proteus mirabilis, Escherichia coli and Klebsiella aerogenes. It is observed that in comparison to Schiff bases of 4-amino antipyrine, pyrazole Schiff bases are better for inhibition for these selected Gram positive and Gram negative bacterial strains.

scholarly journals Antibacterial Activity by Hemolymph Defensin from the Hard Tick Haemaphysalis longicornis

2018 ◽  
Author(s):  
Yurika Yada ◽  
Melbourne Rio Talactac ◽  
Kodai Kusakisako ◽  
Emmanuel Pacia Hernandez ◽  
Remil Linggatong Galay ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Antibacterial Activity ◽  
Antimicrobial Peptides ◽  
Micrococcus Luteus ◽  
Fluorescent Antibody ◽  
Cysteine Residues ◽  
Hard Tick ◽  
Haemaphysalis Longicornis ◽  
Gram Positive ◽  
Gram Positive Bacteria

Ticks are key vectors of some important diseases of humans and animals. Although they are carriers of disease agents, the viability and development of ticks are not harmed by the infectious agents due to their innate immunity. Antimicrobial peptides directly protect hosts against pathogenic agents such as viruses, bacteria, and parasites. Among the identified and characterized antimicrobial peptides, defensins have been considerably well studied. Defensins, which contain intramolecular disulfide bridges between cysteine residues, are commonly found among fungi, plants, invertebrates, and vertebrates. The sequence of the tick hemolymph defensin (HEdefensin) gene from the hard tick Haemaphysalis longicornis was analyzed after identification and cloning from a cDNA library. HEdefensin has a predicted molecular mass of 8.15 kDa and a theoretical isoelectric point of 9.48. Six cysteine residues were also identified in the amino acids. The synthetic HEdefensin peptide only showed antibacterial activity against Gram-positive bacteria such as Micrococcus luteus. A fluorescence propidium iodide exclusion assay also showed that HEdefensin increased the membrane permeability of M. luteus. Additionally, an indirect fluorescent antibody test showed that HEdefensin binds to M. luteus. These results suggested that HEdefensin strongly affects the innate immunity of ticks against Gram-positive bacteria.

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