scholarly journals Production of Enterocins L50A, L50B, and IT, a New Enterocin, by Enterococcus faecium IT62, a Strain Isolated from Italian Ryegrass in Japan

2008 ◽  
Vol 52 (6) ◽  
pp. 1917-1923 ◽  
Author(s):  
Esther Izquierdo ◽  
Audrey Bednarczyk ◽  
Christine Schaeffer ◽  
Yimin Cai ◽  
Eric Marchioni ◽  
...  
Keyword(s):  
Amino Acid ◽  
Enterococcus Faecium ◽  
Amino Acid Sequences ◽  
Italian Ryegrass ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Wide Range ◽  
Molecular Masses ◽  
First Time

ABSTRACT Enterococcus faecium IT62, isolated from ryegrass in Japan, was shown to produce three different bacteriocins, two of which had molecular masses and amino acid sequences that corresponded to those of enterocin L50A and enterocin L50B. These peptides existed, however, as chemically modified forms that were either N formylated or N formylated and oxidized at Met24. The third bacteriocin, named enterocin IT, had a molecular mass of 6,390 Da, was made up of 54 amino acids, and did not correspond to any known bacteriocin. However, enterocin IT was identical to the C-terminal part of the 16-amino-acid-longer bacteriocin 32 (T. Inoue, H. Tomita, and Y. Ike, Antimicrob. Agents Chemother., 50:1202-1212, 2006). For the first time, the antimicrobial activity spectra for enterocins L50A and L50B were determined separately and included a wide range of gram-positive bacteria but also a few gram-negative strains that were weakly sensitive. Slight differences in the activities of enterocins L50A and L50B were observed, as gram-positive bacteria showed an overall higher level of sensitivity to L50A than to L50B, as opposed to gram-negative ones. Conversely, enterocin IT showed a very narrow antimicrobial spectrum that was limited to E. faecium strains, one strain of Bacillus subtilis, and one strain of Lactococcus lactis. This study showed that E. faecium IT62, a grass-borne strain, produces bacteriocins with very different activity features and structures that may be found in strains associated with food or those of clinical origin, which demonstrates that a particular enterocin structure may be widespread and not related to the producer's origin.

Fusobacterium nucleatum, the first Gram-negative bacterium demonstrated to produce polyglutamate

2009 ◽  
Vol 55 (5) ◽  
pp. 627-632 ◽  
Author(s):  
Thomas Candela ◽  
Marie Moya ◽  
Michel Haustant ◽  
Agnès Fouet
Keyword(s):  
In Silico Analysis ◽  
Fusobacterium Nucleatum ◽  
Gram Negative Bacteria ◽  
Negative Bacterium ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
The Third ◽  
Gram Negative Organisms ◽  
First Time

Poly-γ-glutamate has been described in many Gram-positive organisms. When anchored to the surface, it is a capsule and as such a virulence factor. Based on sequence similarities, few Gram-negative organisms have been suggested to synthesize poly-γ-glutamate. For the first time, a Gram-negative bacterium, Fusobacterium nucleatum , is shown to produce and secrete poly-γ-glutamate. Putative poly-γ-glutamate-synthesizing genes from Gram-negative organisms have been compared with their Gram-positive homologs by in silico analysis, i.e., gene sequence and phylogenetic analysis. Clusters of three instead of four genes were highlighted by our screen. The products of the first two genes display similarity with their Gram-positive equivalents, yet the sequences from the Gram-negative organisms can be distinguished from those of the Gram-positives. Interestingly, the sequence of the predicted product of the third gene is conserved among Gram-negative bacteria but displays no similarity to that of either the third or fourth gene of the Gram-positive operons. It is suggested that, like for Gram-positive bacteria, poly-γ-glutamate has a role in virulence for pathogens and one in survival for other Gram-negative bacteria.

scholarly journals Enzymic and structural characterization of nepenthesin, a unique member of a novel subfamily of aspartic proteinases

2004 ◽  
Vol 381 (1) ◽  
pp. 295-306 ◽  
Author(s):  
Senarath B. P. ATHAUDA ◽  
Koji MATSUMOTO ◽  
Sanath RAJAPAKSHE ◽  
Masayuki KURIBAYASHI ◽  
Masaki KOJIMA ◽  
...  
Keyword(s):  
Amino Acid ◽  
Computer Modelling ◽  
Structural Characteristics ◽  
Amino Acid Sequences ◽  
Cysteine Residues ◽  
Aspartic Proteinases ◽  
Protein Databases ◽  
Wide Range ◽  
First Time

Carnivorous plants are known to secrete acid proteinases to digest prey, mainly insects, for nitrogen uptake. In the present study, we have purified, for the first time, to homogeneity two acid proteinases (nepenthesins I and II) from the pitcher fluid of Nepenthes distillatoria (a pitcher-plant known locally as badura) and investigated their enzymic and structural characteristics. Both enzymes were optimally active at pH approx. 2.6 towards acid-denatured haemoglobin; the specificity of nepenthesin I towards oxidized insulin B chain appears to be similar, but slightly wider than those of other APs (aspartic proteinases). Among the enzymic properties, however, the most notable is their unusual stability: both enzymes were remarkably stable at or below 50 °C, especially nepenthesin I was extremely stable over a wide range of pH from 3 to 10 for over 30 days. This suggests an evolutionary adaptation of the enzymes to their specific habitat. We have also cloned the cDNAs and deduced the complete amino acid sequences of the precursors of nepenthesins I and II (437 and 438 residues respectively) from the pitcher tissue of N. gracilis. Although the corresponding mature enzymes (each 359 residues) are homologous with ordinary pepsin-type APs, both enzymes had a high content of cysteine residues (12 residues/molecule), which are assumed to form six unique disulphide bonds as suggested by computer modelling and are supposed to contribute towards the remarkable stability of nepenthesins. Moreover, the amino acid sequence identity of nepenthesins with ordinary APs, including plant vacuolar APs, is remarkably low (approx. 20%), and phylogenetic comparison shows that nepenthesins are distantly related to them to form a novel subfamily of APs with a high content of cysteine residues and a characteristic insertion, named ‘the nepenthesin-type AP-specific insertion’, that includes a large number of novel, orthologous plant APs emerging in the gene/protein databases.

scholarly journals Group IIA secreted phospholipase A2in human serum kills commensal but not clinicalEnterococcus faeciumisolates

2018 ◽  
Author(s):  
Fernanda L. Paganelli ◽  
Helen L. Leavis ◽  
Samantha He ◽  
Nina M. van Sorge ◽  
Christine Payré ◽  
...  
Keyword(s):  
Human Serum ◽  
Enterococcus Faecium ◽  
Opportunistic Infections ◽  
Normal Serum ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Serum Killing ◽  
Normal Human

AbstractHuman innate immunity employs cellular and humoral mechanisms to facilitate rapid killing of invading bacteria. The direct killing of bacteria by human serum is mainly attributed to the activity of the complement system that forms pores in Gram-negative bacteria. Although Gram-positive bacteria are considered resistant to serum killing, we here uncover that normal human serum effectively killsEnterococcus faecium.Comparison of a well-characterized collection of commensal and clinicalE. faeciumisolates revealed that human serum specifically kills commensalE. faeciumstrains isolated from normal gut microbiota, but not clinical isolates. Inhibitor studies show that the human group IIA secreted phospholipase A2 (hGIIA), but not complement, is responsible for killing of commensalE. faeciumstrains in human normal serum. This is remarkable since hGIIA concentrations in ‘non-inflamed’ serum were considered too low to be bactericidal against Gram-positive bacteria. Mechanistic studies showed that serum hGIIA specifically causes permeabilization of commensalE. faeciummembranes. Altogether, we find that a normal serum concentration of hGIIA effectively kills commensalE. faeciumand that hGIIA resistance of clinicalE. faeciumcould have contributed to the ability of these strains to become opportunistic pathogens in hospitalized patients.ImportanceHuman normal serum contains antimicrobial components that effective kill invading Gram-negative bacteria. Although Gram-positive bacteria are generally considered resistant to serum killing, here we show that normal human effectively kills the Gram-positiveEnterococcus faeciumstrains that live as commensals in the gut of humans. In contrast, clinicalE. faeciumstrains that are responsible for opportunistic infections in debilitated patients are resistant against human serum. The key factor in serum responsible for killing is group IIA secreted phospholipase A2 (hGIIA) that effectively destabilizes commensalE. faeciummembranes. We believe that hGIIA resistance by clinicalE. faeciumcould have contributed to the ability of these strains to cause opportunistic infections in hospitalized patients. Altogether, understanding mechanisms of immune defense and bacterial resistance could aid in further development of novel anti-infective strategies against medically important multidrug resistant Gram-positive pathogens.

scholarly journals The antimicrobial potentialities of (Nk-lysin peptides of chicken, bovine, and human) against bacteria and rotavirus

2021 ◽  
Author(s):  
Maged. M Mahmoud ◽  
Ahmed M. Al-Hejin ◽  
Turki S Abujaml ◽  
S Abd-Elmaksoud ◽  
Salem M. El-Hamidy ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Klebsiella Oxytoca ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Beta Lactamases ◽  
Gram Positive Bacteria ◽  
The Past ◽  
Antiviral Activities ◽  
First Time

Abstract For the first time, this study was carried out to investigate and evaluate the relative antibacterial activity of three different Nk-lysin peptides from human, chicken, and bovine activity compared to Gram-negative and Gram-positive bacteria as well as antiviral activity against rotavirus (strain SA-11) and finally mechanisms of action optionality. This report is the first of its kind that investigates the increased antimicrobial ability of (Nk-lysin + AgNPs) and (Nk-lysin + human IL-2) combinations against S. typhi activity by carrying out direct comparison under similar experimental settings. Our results showed that gram-negative and gram-positive microorganisms, including Streptococcus pyogenes, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Shigella sonnei, Klebsiella pneumoniae and Salmonella typhimurium, are susceptible to NK-lysin treatment. It was shown in our findings that there was equal potentiality in mixture (Nk-lysin + AgNPs) and (Nk-lysin + human IL-2) for preventing the growth of S. typhi, however, when added together, there was minor increase in the level of action. In our study, the TOHO-1 gene was absent in treated bacteria. Following treatment with Nk-lysin peptides, the beta-lactamases genes (CTX-M-1, M-8, and M-9) were not found in any bacterial strains. The examination did not find any of the plasmid mediated quinolone resistance genes in the bacterial strains as a response to NK-lysin treatment. Nonetheless, no study has been carried out in the past that characterized the antiviral activity of bovine, human and chicken Nk-lysin peptides. Hence, this is the foremost study on the enhanced antimicrobial activity of human, bovine and chicken Nk-lysin peptides against Rotavirus (strain SA-11). The findings of the study demonstrated that the powerful antiviral activities were exhibited by Nk-lysin peptides against Rotavirus (strain SA-11). Based on the comparison between these peptides, it can be concluded that there is an evident potent antiviral activity of bovine Nk-lysin against Rotavirus (strain SA-11) as it restrains infection by up to 90%. However, growth was restricted by 80% by chicken Nk-lysin and by 50% by the human peptide.

scholarly journals First results of complex studies of modern microorganisms by physico-chemical and mineral-geochemical methods

2021 ◽  
Vol 9 ◽  
pp. 3-33
Author(s):  
V. I. Silaev ◽  
◽  
A. V. Kokin ◽  
N. V. Pavlovich ◽  
S. N. Shanina ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Amino Acid ◽  
Chemical Composition ◽  
Amino Acid Content ◽  
Total Amino Acid ◽  
Strong Positive Correlation ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

We studied 14 samples of gram-negative and gram-positive bacteria, unicellular yeasts and green algae using optical, atomic force and analytical scanning electron microscopy, thermal analysis, gas chromatography, infrared spectroscopy, inductively coupled plasma mass spectrometry and isotope mass spectrometry. In shape, the cells of microorganisms vary from rod-shaped to lenticular and coccoid, in size they range from mesonanometer to micrometer. A strong positive correlation was found between the extreme cell sizes. An admixture of inorganic chemical elements — Mg, Ca, Ba, Na, K, Cu, Zn, P, S, Cl and submicron-sized precipitates of mineral phases — carbonates, phosphate sulfates, hydrogen sulfate phosphates, hydrogen phosphates, halite, kaolinite, was found in the chemical composition of the studied microorganisms, metal alloys of brass composition, baddeleyite. Among the 45 microelements identified in microorganisms, there were 7 essential elements (E), 17 physiogenically active (FA) and 19 abiotic (AB). The total concentration of trace elements ranged from 0.003—0.26 wt. %. The value of the essential coefficient — E / AB — averaged 196 ± 153. Microorganisms were characterized by a mixed fat-protein elemental composition, they contained 14 amino acids belonging to the aliphatic, aromatic, basic, acidic, hydroxyl, imino and sulfur-containing groups. The total amino acid content ranged from 409 to 942 (682 ± 221) mg/g. Up to half of the amino acids were represented by the left (L) and right (D) enantiomers. The degree of racemization (D / L) ranged from 0.01 to 0.37. Yeast and chlorella were characterized by the most isotopically heavy composition of carbon in combination with relatively isotopically light nitrogen. In bacteria, a statistically lighter carbon was found in combination with a much heavier nitrogen. According to a number of properties — the chemical composition of organic matter, microelements, the degree of enrichment with antibiotic elements, the content of amino acids and the degree of their racemization — gram-negative and gram-positive bacteria differed. In general, the studied biological microorganisms were fundamentally different from the abiogenic organic substances found in meteorites and products of modern volcanism regarding their elemental and amino acid composition, carbon and nitrogen isotopes.

A hydrogel directly assembled from a copper metal–organic polyhedron for antimicrobial application

2019 ◽  
Vol 55 (15) ◽  
pp. 2206-2209 ◽  
Author(s):  
Yu Qin ◽  
Lin-Lin Chen ◽  
Wei Pu ◽  
Peng Liu ◽  
Shi-Xi Liu ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Copper Metal ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Metal Organic ◽  
First Time

A hydrogel was directly assembled from a Cu-MOP by a facile procedure without adding any polymers for the first time, and it exhibited excellent antibacterial activity towards both Gram-negative and Gram-positive bacteria.

scholarly journals DETERMINATION OF ANTIBACTERIAL ACTIVITY OF SOME IMPORTANT SPICES

2015 ◽  
Vol 3 (10) ◽  
pp. 57-64
Author(s):  
Ranganathan Kapilan
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Maximum Activity ◽  
Gram Negative Bacteria ◽  
Alcoholic Extract ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Wide Range

Wide range of plant extracts are used for medicinal purposes as they are very cheap, efficient, harmless and do not cause any side effects. Spices are parts of different plants and they add special aroma and taste to the food preparations. The aim of the study was to determine the antimicrobial activity of some important naturally grown spices against gram positive and gram negative pathogenic bacteria. Antibacterial activity of the spices was tested against gram positive bacteria Bacillus pumilus, Bacillus cereus and Staphylococcus aureus and gram negative bacteria Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa using aqueous, ethanolic, methanolic and liquid nutrient extracts. Among all the extracts tested alcoholic extracts of Cardamom (Elettaria cardamom), clove (Eugenia caryophyllus) and lemongrass (Cymbopogoncitratus) showed maximum antimicrobial activity against gram negative bacteria while alcoholic extract of Cardamom (Elettaria cardamom) and lemongrass (Cymbopogoncitratus) showed maximum activity against gram positive bacteria. All the spices tested in this study proved that they have antibacterial activity and the maximum activity index (1.39) was exhibited by the ethanol extract of cardamom against E.coli.

scholarly journals Synthesis, Characterization, and Antimicrobial Studies of Novel Series of 2,4-Bis(hydrazino)-6-substituted-1,3,5-triazine and Their Schiff Base Derivatives

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Hessa H. Al-Rasheed ◽  
Essam N. Sholkamy ◽  
Monirah Al Alshaikh ◽  
Mohammed R. H. Siddiqui ◽  
Ahmed S. Al-Obaidi ◽  
...  
Keyword(s):  
Schiff Base ◽  
Pathogenic Bacteria ◽  
Specific Effect ◽  
Antagonistic Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Antimicrobial Studies ◽  
Schiff Base Derivatives ◽  
Wide Range

The present work represents the synthesis, characterization, and antimicrobial studies of novel series of 2,4-bis(hydrazino)-6-substituted-1,3,5-triazine and their Schiff base derivatives. IR, NMR (H1 and C13), elemental analysis, and LC-MS characterized the prepared compounds. The biological activity of the target products was evaluated as well. Twenty-two of the prepared compounds were selected according to their solubility in aqueous DMSO. Only eight compounds showed good activity against the selected pathogenic bacteria and did not show antagonistic effect against fungus Candida albicans. Two compounds 4k and 5g have wide-range effect presently in Gram-positive and Gram-negative bacteria while other compounds (4f, 4i, 4m, 5d, 6i, and 6h) showed specific effect against the Gram-negative or Gram-positive bacteria. The minimum inhibitory concentration (MIC, μg/mL) of 4f, 4i, 4k, and 6h compounds against Streptococcus mutans was 62.5 μg/mL, 100 μg/mL, 31.25 μg/mL, and 31.25 μg/mL, respectively. The MIC of 4m, 4k, 5d, 5g, and 6h compounds against Staphylococcus aureus was 62.5 μg/mL, 31.25 μg/mL, 31.25 μg/mL, 100 μg/mL, and 62.5 μg/mL, respectively. The MIC of 4k, 5g, and 6i compounds against Salmonella typhimurium was 31.25 μg/mL, 100 μg/mL, and 62.5 μg/mL, respectively. The MIC of 6i compound against Escherichia coli was 62.5 μg/mL.

scholarly journals Synthesis, characterization, and in vitro antimicrobial investigation of novel pyran derivatives based on 8-hydroxyquinoline

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohamed Rbaa ◽  
Abdelhadi Hichar ◽  
Omar Bazdi ◽  
Younes Lakhrissi ◽  
Khadija Ounine ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Magnetic Resonance ◽  
Penicillin G ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Wide Range

Abstract Background 8-Hydroxyquinoline derivatives are known for their extensive applications in the field of analytical chemistry and separation techniques; their complexes with transition metals also exhibit antibacterial and antifungal activity. Results In the present study, we synthesized a new series of pyranoquinoline derivatives and evaluated their antibacterial activities. The structures of the synthesized compounds were characterized by Fourier transform infrared (FT-IR), hydrogen-1 nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, and elemental analysis. All the prepared compounds were evaluated in vitro as antimicrobial agents against Gram-positive and Gram-negative bacterial strains (Escherichia coli (ATCC35218), Staphylococcus aureus (ATCC29213), Vibrio parahaemolyticus (ATCC17802), and Pseudomonas aeruginosa (ATCC27853)). The screening test was determined by using the standard protocol of disc diffusion method (DDM). Conclusion We have synthesized new pyranic compounds bearing an 8-hydroxyquinoline moiety on their structure. The preliminary screening results showed that all the tested compounds have a remarkable inhibitory effect on the growth of the majority of the tested bacterial strains compared to the standard antibiotic (penicillin G), and the chlorinated compound (Q1) is more active against Gram-positive bacteria than Gram-negative bacteria such as the Staphylococcus aureus strain which is the most sensitive. Gram-positive bacteria are responsible for a wide range of infectious diseases, and rising resistance in this group is causing increasing concern. Thus, this study develops novel heterocyclic compound derivatives of 8-hydroxyquinoline that have demonstrated good antibacterial activity against Gram-positive bacteria. Graphical abstract

scholarly journals Physiological and potentially pathogenic microbial flora in bats

2021 ◽  
Author(s):  
Maria Foti ◽  
Mariateresa Teresa Spena ◽  
Vittorio Fisichella ◽  
Antonietta Mascetti ◽  
Marco Colnaghi ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Southern Italy ◽  
Bacterial Flora ◽  
Point Of View ◽  
Gram Positive ◽  
European Continent ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Myotis Myotis ◽  
First Time

Abstract The study of bats has a significant interest from a systematic, zoogeographic, ecological and physiological point of view, but their possible role as potential carriers of pathogenic bacteria is little explored and very little research has been carried out on the European continent. The aim of this study is to investigate the culturable aerobic enteric, conjunctival and oral bacterial flora of bats living in southern Italy to determine the physiological bacterial microflora and to investigate the possible occurrence of pathogenic bacteria. Five hundred and sixty-seven samples were collected from 189 individuals of 4 species of bats (Myotis myotis, Myotis capaccinii, Miniopterus schreibersii and Rhinolophus hipposideros). The sampling was carried out in six areas of the territory of Sicily and Calabria (southern Italy). All samples were examined for Gram negative bacteria; conjunctival and oral swabs were also submitted to bacteriological examination for Gram positive bacteria. Four hundred thirteen Gram negative strains were isolated. Of these, 377 belonged to 17 different genera of the Enterobacteriaceae Group and 30 to 5 other Families. One hundred eighty three Gram positive strains were isolated. Of these, 73 belonged to Staphylococcaceae Family, 72 to Bacillaceae Family and 36 to 4 other Families. To the best of our knowledge, this is the first time that some of these genera have been isolated from bats. The results confirmed that bats play an important role in the ecology and circulation of potentially pathogenic bacteria not only for wild species but also for domestic animals and for humans.

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