scholarly journals Optimization of Agitation Rate in Bioreactor Increases Chitinase Activity of Serratia marcescens PT6

2020 ◽  
Vol 147 ◽  
pp. 03019
Author(s):  
Amara Faiz Wriahusna ◽  
Niswah Umhudloh Dzakiyya ◽  
Indun Dewi Puspita ◽  
Sri Pudjiraharti
Keyword(s):  
Serratia Marcescens ◽  
Bacterial Growth ◽  
Agar Medium ◽  
Chitinase Activity ◽  
Colloidal Chitin ◽  
Gram Negative Bacteria ◽  
Agitation Rate ◽  
Anova Analysis ◽  
Gram Negative ◽  
Shrimp Pond

Serratia marcescens PT6 is a Gram-negative bacteria isolated from shrimp pond sediment that capable of producing chitinase. This study aimed to observe the effect of agitation rate on growth and chitinase activity of S. marcescens PT-6 in a bioreactor. The production of chitinase was done in 1.5 l bioreactor using colloidal chitin broth at the condition of pH 7, the temperature of 30°C, aeration of 0.04 vvm, and variation of agitation rate (200, 350, 500 rpm). Bacterial growth was measured by colonies counting in agar medium, while chitinase activity was measured by means of colorimetric every day for four days incubation. The results of ANOVA analysis show that the agitation rate had no effect on bacterial growth, but a significant effect (P<0.05) was observed on chitinase activity. The highest growth and chitinase activity were obtained at 200 rpm, with the highest chitinase activity of 0.006 ± 0.001 U/ml was at day-2. This study implies that the optimized agitation rate in the bioreactor increased the chitinase activity produced by S. marcescens PT-6.

scholarly journals Quorum sensing modulatory effect of sound stimulation on Serratia marcescens and Pseudomonas aeruginosa

2016 ◽  
Author(s):  
Vijay Kothari ◽  
Pooja Patel ◽  
Chinmayi Joshi ◽  
Brijesh Mishra ◽  
Shashikant Dubey ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Serratia Marcescens ◽  
Bacterial Growth ◽  
Gram Negative Bacteria ◽  
Sound Waves ◽  
Sound Stimulation ◽  
Gram Negative ◽  
Metabolite Production ◽  
Frequency Sound

AbstractEffect of nine different mono-frequency sound stimuli on two gram-negative bacteria (Pseudomonas aeruginosa and Serratia marcescens) was investigated. Frequency of the test sound ranged from 100 Hz to 2,000 Hz. Both the test bacteria responded differently to sonic stimulation. Sound corresponding to 600 HZ caused a notable reduction in quorum sensing (QS) regulated production of the pigment pyoverdine by P. aeruginosa. 400 Hz sound affected prodigiosin production by S. marcescens the most. 500 Hz sound could enhance prodigiosin production without affecting growth of the producing bacterium, suggesting the effect purely to be QS modulatory. This study has demonstrated the capacity of the sound waves of affecting bacterial growth and quorum sensing regulated metabolite production.

scholarly journals Functional and structural characterization of Serratia marcescens ExbB: determinants of the interaction with HasB/TonB

2021 ◽  
Author(s):  
Valérie Biou ◽  
Ricardo Jorge D Adaixo ◽  
Mohamed Chami ◽  
Pierre-Damien Coureux ◽  
Benoist Laurent ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Molecular Motor ◽  
Opportunistic Pathogen ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
New Class ◽  
Heme Acquisition ◽  
Shed Light

ExbBD is part of a cytoplasmic membrane molecular motor driven by the proton-motive force. It belongs to the larger family of motors involved in nutriment import across the outer membrane of Gram-negative bacteria (ExbBD), flagellar rotation (MotAB) or late steps of cell division in Gram-negative bacteria (TolQR). ExbB and ExbD are integral membrane proteins with three (ExbB) or one (ExbD) transmembrane segment. Here we have solved by single-particle cryo-EM the structures of ExbB alone and of the ExbB-ExbD complex of the opportunistic pathogen Serratia marcescens. ExbBSm alone behaves as a stable pentamer, and the complex displays the ExbB5-ExbD2 stoichiometry. This is similar to what has been observed for ExbB-ExbD complexes from Escherichia coli and Pseudomonas savastanoi as well as MotAB complexes from various species. We identified residues located in the first TM of ExbBSm and ExbBEc that are likely involved in the interaction with TonB/HasB and that are essential for function. ExbBSm has a ca. 40 residues long periplasmic extension absent in E. coli. Such long ExbBs are found in some Gammaproteobacteria, and several genera of Alphaproteobacteria. We show that this extension interacts with HasB, a dedicated TonB paralog from the heme acquisition system (Has) from S. marcescens. We also show that it is involved in heme acquisition via the Has system from S. marcescens. ExbBSm represents thus a new class of ExbB protein and our results shed light on the specificity determinants between the ExbB-ExbD complex and their associated TonB partners.

scholarly journals Bacterial keratitis: similar bacterial and clinical outcomes in female versus male New Zealand White rabbits infected with Serratia marcescens

2021 ◽  
Author(s):  
Eric G Romanowski ◽  
Sanya Yadav ◽  
Nicholas A Stella ◽  
Kathleen A Yates ◽  
John E Romanowski ◽  
...  
Keyword(s):  
New Zealand ◽  
Serratia Marcescens ◽  
Viral Infections ◽  
Zealand White Rabbit ◽  
Gram Negative Bacteria ◽  
Bacterial Keratitis ◽  
Gram Negative ◽  
Single Sex ◽  
New Zealand White Rabbits ◽  
Microbiological Parameters

Females and males respond differently to a number of systemic viral infections. Differences between females and males with respect to the severity of keratitis caused by Gram-negative bacteria such as Serratia marcescens are less well established. In this study we injected female and male New Zealand White rabbit corneas with a keratitis isolate of S. marcescens and evaluated the eyes after 48 hours for a number of clinical and microbiological parameters. No statistical differences in bacterial burden and corneal scores were recorded between female and male rabbits although there was a non-significant trend toward a higher frequency of female rabbits demonstrating hypopyons. This data suggests that for experimental bacterial keratitis studies involving Gram-negative rods, a single sex or mixed group of rabbit is sufficient for evaluating pathology and bacterial burdens. This will reduce the number of animals used for subsequent studies.

scholarly journals Pattern of antibiotic resistance of various strains of bacteria causing acute tonsillitis

2021 ◽  
Vol 7 (6) ◽  
pp. 994
Author(s):  
N. Jyothsna ◽  
A. Ramya ◽  
K. Abhilash ◽  
Bathsa Liza Johnson
Keyword(s):  
Antibiotic Resistance ◽  
Bacterial Growth ◽  
Bacterial Strain ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Acute Tonsillitis ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Antibiotic Drugs ◽  
Significant Difference

<p class="abstract"><strong>Background:</strong> Our study was done to determine the pattern of antibiotic resistance of various strains of bacteria causing acute tonsillitis.</p><p class="abstract"><strong>Methods:</strong> the study was a randomized cross sectional study. Patients matching the inclusion criteria were included. Duration of study was 6 months.</p><p class="abstract"><strong>Results:</strong> Out of 120 cases, 46 cases showed no bacterial growth (NBG) and 74 cases showed bacterial growth. 42 cases were gram-negative bacterial strain and 32 cases were positive bacterial strain out of 72 bacterial grown cases. A list of 25 antibiotic drugs in gram-negative and 31 drugs in gram-positive strain, their sensitivity and resistance were taken and noted. Among gram-negative bacteria imipenem (71.4%) showed highest sensitivity. Highest antibiotic resistance was seen in ampicillin (85.71%). Least sensitivity is observed in clindamycin, amoxicillin+clavulanic acid with 2.38%. Among gram-positive bacteria, highest sensitivity was noted in cefotaxime (75%). Highest antibiotic resistance was seen in cotrimoxazole (46.8%). Least sensitivity is observed in netilmicin, sulbactam with 3.12%.</p><p class="abstract"><strong>Conclusions:</strong> The number of drugs resistant to the gram-positive bacteria are lesser than number of drugs sensitive, which showed significant difference (p&lt;0.05). Significant difference of antibiotic drugs was not found in gram-negative bacteria. Our study findings helped in appropriate and guarded use of the antibiotic drugs in acute tonsillitis, minimizing the exposure of individuals to antibiotic resistance by choosing an appropriate sensitive drug, therefore improving the quality of therapy.</p>

scholarly journals Chitinase Activity of Serratia marcescens PT-6 Cultured in Bioreactor with Various Aeration Rate

2020 ◽  
Vol 147 ◽  
pp. 03010
Author(s):  
Niswah Umhudloh Dzakiyya ◽  
Indun Dewi Puspita ◽  
Sri Pudjiraharti
Keyword(s):  
Serratia Marcescens ◽  
Bacterial Growth ◽  
Colorimetric Assay ◽  
Chitinase Activity ◽  
Aeration Rate ◽  
Agitation Speed ◽  
Bacterial Colony ◽  
Shrimp Shell ◽  
Shrimp Shell Waste ◽  
Chitinase Production

Chitin is a biopolymer composed of N-acetylglucosamine (NAG) monomers. Bacterial chitinase helps in bioconversion process of chitin from shrimp shell waste into NAG. This study aimed to determine the effect of aeration on chitinase activity, NAG concentration in medium, bacterial growth, and pH medium; to determine the optimum aeration on chitinase production of Serratia marcescens PT-6. Chitinase was produced using a 1.5 L bioreactor at pH 7, 30°C, 200 rpm agitation speed, and variation of aeration rates (0.4, 0.6 and 0.8 vvm). Parameters examined included pH, bacterial growth (log CFU/ml), chitinase activity (U/ml), and NAG concentration in medium (µg/ml). Bacterial growth was measured by enumeration of bacterial colony in medium, while chitinase activity and NAG concentration were analyzed by colorimetric assay. Parameters was measured every 8 hours during 60 hours of incubation. Aeration rate showed a significant effect (P≤0.05) on chitinase activity and NAG concentration, but not significant (P≥0.05) on bacterial growth and pH medium. Optimum aeration rate on producing chitinase was 0.6 vvm with the highest chitinase activity of 0.0125 U/ml at 40 hours incubation. This study implies that optimization of bioreactor condition improved the production of chitinase by S. marcescens PT-6.

scholarly journals Antibacterial Activities of Actinomycete Isolates Collected from Soils of Rajshahi, Bangladesh

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Md. Ajijur Rahman ◽  
Mohammad Zahidul Islam ◽  
Md. Anwar Ul Islam
Keyword(s):  
Antibacterial Activity ◽  
Secondary Metabolites ◽  
Inhibitory Activity ◽  
Pure Culture ◽  
Agar Medium ◽  
Antibacterial Activities ◽  
Soil Samples ◽  
Indicator Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative

This study was performed to isolate actinomycete colonies having antibacterial activity from soil samples collected from different places around Rajshahi, Bangladesh. Thirty actinomycete colonies were isolated in pure culture from five soil samples using Starch-casein-nitrate-agar medium. The isolates were grouped in five color series based on their aerial mycelia color and screened for their antibacterial activity against a range of test bacteria. Sixteen isolates (53.3%) were found to have moderate to high activity against four gram-positive and four gram-negative bacteria. Since many isolates showed inhibitory activity against indicator bacteria, it is suggestive that Bangladeshi soil could be an interesting source to explore for antibacterial secondary metabolites.

scholarly journals Effect of Frequency Magnetic field on Gram Positive and Gram Negative Bacteria

2019 ◽  
Author(s):  
Mohamad Reza Bayatiani ◽  
fatemeh seif ◽  
mohamad Arjomandzadegan ◽  
alireza moradabadi ◽  
arash parvin
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Bacterial Growth ◽  
Electromagnetic Waves ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Living Organisms ◽  
Escherichia Coli Bacteria ◽  
Growth Of Bacteria

Abstract Objective It is necessary to evaluate the harmful or useful effects of electromagnetic waves on living organisms and determine the threshold of these radiations. In this research, the effect of magnetic fields on the growth of gram-positive ( Staphylococcus aureus ) and gram-negative ( Escherichia coli ) bacteria has been evaluated.Results In Gram-negative bacteria such as E. coli in both magnetic fields 1mT and 2mT at different frequencies, an additive effect was seen on the growth of bacteria. When the frequency increased the trend of increasing bacterial growth, slowed. In Gram-positive bacteria such as Staphylococcus, this effect was less. In 1mT magnetic field, the growth of bacteria was seen but the 2mT field was virtually ineffective and the differences between two groups at different frequencies were not significant. Also, significant changes didn't observe with increasing frequency. Study of bacterial growth in terms of frequency in both case and control groups showed an increasing trend. With increasing frequency from 50 Hz to 150Hz significantly increased the rate of bacterial growth and the growth in the higher frequencies more than lower frequencies. Magnetic field had increment effect on the growth of bacteria. This effect was greater on gram-negative than on gram-positive.

scholarly journals Development of transport systems of quinolone class antibiotics through outer membrane vesicles (OMVs) in Gram-negative bacteria

2018 ◽  
Author(s):  
Carlos Fernando Macedo da Silva ◽  
Marcelo Lancellotti
Keyword(s):  
Outer Membrane ◽  
Bacterial Growth ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Transport Systems ◽  
Gram Negative Bacteria ◽  
Extracellular Medium ◽  
Gram Negative ◽  
Resistance To Antibiotics ◽  
Cell Reproduction

Multi-resistance to antibiotics in Gram-negative bacteria has been reported in several studies, which make more effective methods of controlling and eliminating these bacteria necessary. To overcome multiresistant profiles, we used OMVs (Outer Membrane Vesicles) as carriers of levofloxacin to encapsulate and transport the drug from the extracellular medium into the cell, overcoming resistance barriers and inhibiting cell reproduction machinery. Prepackaged formulations in this manner were quite effective and, in some cases, totally inhibited bacterial growth by making the drug efficient again.

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