SOSUI-GramN: high performance prediction for sub-cellular localization of proteins in Gram-negative bacteria

The objective of the present study was to identify antimicrobial peptides present in several digests of commercial caseins with gastric enzymes. The most active hydrolysate against Escherichia coli ATCC 25922 and Listeria innocua CECT 910T corresponded to a pepsin digest of bovine κ-casein. The protein digest was first separated by semipreparative high-performance liquid chromatography (HPLC), and the most active fractions were again subjected to a second chromatographic step. Finally, identification of the active peptides was carried out by online and offline HPLC–electrospray ionization–tandem mass spectrometry. By means of this technique, 21 peptides were identified in the active HPLC fractions. Although most were derived from bovine κ-casein, some of the identified fragments corresponded to β-casein and αs-casein fragments, a result of the presence of small amounts of these proteins in the preparation of κ-casein. Some of the peptides identified were chemically synthesized and showed antibacterial effects against several gram-positive and gram-negative bacteria. Among the synthesized peptides, κ-casein f(18–24), f(30–32), and f(139–146) were most effective against all bacteria tested. The antibacterial effect of these peptides is discussed in relation to their amino acid sequences.

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Production and characterization of semi-quinolone antibiotic produced by Streptomyces griseorubens

10.21203/rs.3.rs-121133/v1 ◽

2020 ◽

Author(s):

Waleed Abdulkhair ◽

Mousa Alghuthaymi

Keyword(s):

High Performance ◽

Gel Filtration ◽

Nuclear Magnetic Resonance Analysis ◽

Rrna Gene ◽

Molecular Formula ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Antibacterial Compound ◽

Flash Column Chromatography ◽

Active Peak

Abstract This work is an attempt to overcome antimicrobial resistance problem which dispersed worldwide inparticular developing countries due to misuse of antibiotics. Actinobacteria were isolated and screenedagainst selected resistant Gram-negative bacteria to detect the powerful antibacterial activity.Identification of the most potent actinobacterial isolate has been carried out using classical and geneticalmethods. Antibacterial compound has been extracted, purified and characterized using accurate and morespecific techniques and instruments. Among forty actinobacterial isolates, only twenty-two isolates couldinhibit the growth of Gram-negative bacteria. The most potent isolate Eg-7 was identified as S.griseorubens, which has a typical 16S rRNA gene. The antibacterial compound was extracted using ethylacetate, and separated by High Performance Liquid Chromatography using methanol and water as amobile phase. Five active peaks were displayed and retained in the range 40 – 45 min, but the last threepeaks were retained at 41.90, 43.43, and 44.54 min, respectively. The crude extract was analyzed byliquid chromatography mass spectrum, where the active peak was displayed at 721.325 m/z. Theantibacterial compound was purified using flash column chromatography and gel filtration columnchromatography. The active fraction was analyzed by Infra-Red spectrum, where a broad absorption at3338 cm-1 was displayed. Molecular formula of an antibacterial compound was determined by massspectrum as C35H26N6O4. Nuclear magnetic resonance analysis was carried out for an antibacterialcompound. These results suggest that a new antibacterial compound that similar quinolone could beproduced by S. griseorubens and exhibited a higher activity against Gram-negative bacteria.

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Stability of Meropenem and Piperacillin/Tazobactam with Heparin in Various Peritoneal Dialysis Solutions

Peritoneal Dialysis International ◽

10.3747/pdi.2017.00274 ◽

2018 ◽

Vol 38 (6) ◽

pp. 430-440

Author(s):

Karryl Mendes ◽

Harmanjeet Harmanjeet ◽

Mohammed Sedeeq ◽

Ankit Modi ◽

Troy Wanandy ◽

...

Keyword(s):

Peritoneal Dialysis ◽

High Performance ◽

Color Change ◽

Anticoagulant Activity ◽

Storage Conditions ◽

Gram Negative Bacteria ◽

Ph Change ◽

Gram Negative ◽

Extended Spectrum Beta Lactamase ◽

The Stability

Background Infections caused by ceftazidime-resistant Pseudomonas and extended-spectrum beta-lactamase (ESBL)-producing gram-negative bacteria are increasing worldwide. Meropenem and piperacillin/tazobactam (PIP/TZB) are recommended for the treatment of peritoneal dialysis-associated peritonitis (PDAP) caused by ceftazidime-resistant Pseudomonas and other resistant gram-negative bacteria. Patients may also receive intraperitoneal heparin to prevent occlusion of their catheters. However, the stability of meropenem or PIP/TZB, in combination with heparin, in different types of peritoneal dialysis (PD) solutions used in clinical practice is currently unknown. Therefore, we investigated the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. Methods A total of 15 PD bags (3 bags for each type of PD solution) containing meropenem and heparin and 24 PD bags (3 bags for each type of PD solution) containing PIP/TZB and heparin were prepared and stored at 4°C for 168 hours. The same bags were stored at 25°C for 3 hours followed by 10 hours at 37°C. An aliquot withdrawn before storage and at defined time points was analyzed for the concentration of meropenem, PIP, TZB, and heparin using high-performance liquid chromatography. Samples were also analysed for particle content, pH and color change, and the anticoagulant activity of heparin. Results Meropenem and heparin retained more than 90% of their initial concentration in 4 out of 5 types of PD solutions when stored at 4°C for 168 hours, followed by storage at 25°C for 3 hours and then at 37°C for 10 hours. Piperacillin/tazobactam and heparin were found to be stable in all 8 types of PD solutions when stored under the same conditions. Heparin retained more than 98% of its initial anticoagulant activity throughout the study period. No evidence of particle formation, color change, or pH change was observed at any time under the storage conditions employed in the study. Conclusions This study provides clinically important information on the stability of meropenem and PIP/TZB, each in combination with heparin, in different PD solutions. The use of meropenem-heparin admixed in pH-neutral PD solutions for the treatment of PDAP should be avoided, given the observed sub-optimal stability of meropenem.

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Bacterial-Mucosal Cell Junctional Complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050731 ◽

1974 ◽

Vol 32 ◽

pp. 144-145

Author(s):

Roger C. Wagner

Keyword(s):

Intestinal Wall ◽

Rat Colon ◽

Mucosal Cell ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Mucosal Cells ◽

Mucosal Lining ◽

Degenerative Alterations ◽

Junctional Complexes ◽

Intestinal Mucosal Cells

Bacteria exhibit the ability to adhere to the apical surfaces of intestinal mucosal cells. These attachments either precede invasion of the intestinal wall by the bacteria with accompanying inflammation and degeneration of the mucosa or represent permanent anchoring sites where the bacteria never totally penetrate the mucosal cells.Endemic gram negative bacteria were found attached to the surface of mucosal cells lining the walls of crypts in the rat colon. The bacteria did not intrude deeper than 0.5 urn into the mucosal cells and no degenerative alterations were detectable in the mucosal lining.

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Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123830 ◽

1992 ◽

Vol 50 (1) ◽

pp. 686-687

Author(s):

Jacob S. Hanker ◽

Paul R. Gross ◽

Beverly L. Giammara

Keyword(s):

Chronic Arthritis ◽

Blood Cultures ◽

Gram Negative Bacteria ◽

Infectious Arthritis ◽

Bacterial Arthritis ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

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Ultrastructure of periplasmic bodies in gram-negative bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160753 ◽

1990 ◽

Vol 48 (3) ◽

pp. 640-641

Author(s):

Xie Nianming ◽

Ding Shaoqing ◽

Wang Luping ◽

Yuan Zenglin ◽

Zhan Guolai ◽

...

Keyword(s):

Electron Microscope ◽

Campylobacter Jejuni ◽

Proteus Mirabilis ◽

Shigella Flexneri ◽

Morphological Description ◽

Gram Negative Bacteria ◽

Periplasmic Space ◽

Clostridium Tetani ◽

Gram Negative ◽

Brucella Canis

Perhaps the data about periplasmic enzymes are obtained through biochemical methods but lack of morphological description. We have proved the existence of periplasmic bodies by electron microscope and described their ultrastructures. We hope this report may draw the attention of biochemists and mrophologists to collaborate on researches in periplasmic enzymes or periplasmic bodies with each other.One or more independent bodies may be seen in the periplasmic space between outer and inner membranes of Gram-negative bacteria, which we called periplasmic bodies. The periplasmic bodies have been found in seven species of bacteria at least, including the Pseudomonas aeroginosa. Shigella flexneri, Echerichia coli. Yersinia pestis, Campylobacter jejuni, Proteus mirabilis, Clostridium tetani. Vibrio cholerae and Brucella canis.

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Dual stain kit for the microscopic gram classification of ocular infection bacteria

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147089 ◽

1993 ◽

Vol 51 ◽

pp. 248-249

Author(s):

Jacob S. Hanker ◽

Dale N. Holdren ◽

Kenneth L. Cohen ◽

Beverly L. Giammara

Keyword(s):

Contact Lenses ◽

Ocular Infection ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Gram Staining ◽

Ocular Infections ◽

Different Types ◽

Culture Positive ◽

Increased Susceptibility

Keratitis and conjunctivitis (infections of the cornea or conjunctiva) are ocular infections caused by various bacteria, fungi, viruses or parasites; bacteria, however, are usually prominent. Systemic conditions such as alcoholism, diabetes, debilitating disease, AIDS and immunosuppressive therapy can lead to increased susceptibility but trauma and contact lens use are very important factors. Gram-negative bacteria are most frequently cultured in these situations and Pseudomonas aeruginosa is most usually isolated from culture-positive ulcers of patients using contact lenses. Smears for staining can be obtained with a special swab or spatula and Gram staining frequently guides choice of a therapeutic rinse prior to the report of the culture results upon which specific antibiotic therapy is based. In some cases staining of the direct smear may be diagnostic in situations where the culture will not grow. In these cases different types of stains occasionally assist in guiding therapy.

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