scholarly journals Molecular Characterization and Toxicity of Heavy Metal Quinary Mixtures on Enterobacter cloacae Isolate from Nworie River

2021 ◽  
pp. 52-61
Author(s):  
A. C. Onumajuru ◽  
J. N. Ogbulie ◽  
C. O. Nweke
Keyword(s):  
Heavy Metals ◽  
16S Rrna ◽  
Molecular Characterization ◽  
Inhibitory Concentration ◽  
Fixed Ratio ◽  
Enterobacter Cloacae ◽  
Inhibitory Effect ◽  
Additive Interaction ◽  
Relative Composition ◽  
Toxicity Response

The molecular characterization and toxicity of Cadmium (Cd), Lead (Pb), Zinc (Zn), Chromium (Cr) and Copper (Cu) quinary mixtures on Enterobacter cloacae isolate from Nworie River was investigated. Quinary mixtures of the heavy metals were compounded using fixed ratio (%); and inhibitory effect assessed using inhibition of total dehydrogenase as toxicity response. The mixtures consisted of five heavy metals in the ratios:  Pb (20%) + Cr (20%) + Cd (20%) + Zn (20%) + Cu (20%), Pb (30%) + Cr (20%) + Cd (10%) + Zn (30%) + Cu (10%). Pb (10%) + Cr (10%) + Cd (30%) + Zn (40%) + Cu (10%),   Pb (15%) + Cr (25%) + Cd (25%) + Zn (15%) + Cu (20%), Pb (40%) + Cr (15%) + Cd (5%) + Zn (20%) + Cu(20%). Result obtained showed that toxicity of the metals against the bacterium ranked in the order Cu > Cr >Zn > Pb > Cd. The quinary mixtures Pb (20%) + Cr (20%) + Cd (20%) + Zn (20%) + Cu (20%), Pb (30%) + Cr (20%) + Cd (10%) + Zn (30%) + Cu (10%) and 10%Pb + 10%Cr + 30%Cd + 40%Zn + 10%Cu  showed synergistic interaction, while 15%Pb + 25%Cr + 25%Cd + 15%Zn + 20%Cu and 40%Pb + 15%Cr + 5%Cd + 20%Zn + 20%Cu mixtures were antagonistic and additive respectively. Threshold inhibitory concentration (IC50) of the quinary mixtures was  0.054 ± 0.005mM, 0.053 ± 0.002 mM, 0.038 ± 0.002 mM, 0.077 ± 0.007 mM and 0.058 ± 0.006 mM for the respective mixtures. The toxic index values evaluated for the mixtures exhibited antagonistic, synergistic and additive interaction in the various ratios.  The 16S rRNA and ITSF1 sequences obtained of the isolate showed the phylogenetic placement of the 16S rRNA of the isolate was closely related to Enterobacter cloacae strain DL01 (MH168084). The heavy metals mixtures demonstrated diverse toxicity interaction on the isolate depending on their relative composition, thus poses a threat to aquatic microbial diversity.

Screening and Molecular Characterization of Cellulase Producing Actinobacteria from Litchi Orchard

2019 ◽  
Vol 13 (1) ◽  
pp. 90-101
Author(s):  
Sanju Kumari ◽  
Utkarshini Sharma ◽  
Rohit Krishna ◽  
Kanak Sinha ◽  
Santosh Kumar
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Molecular Characterization ◽  
Biochemical Characterization ◽  
Evolutionary Relationship ◽  
Gene Sequencing ◽  
Cellulase Activity ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Rrna Gene Sequencing

Background: Cellulolysis is of considerable economic importance in laundry detergents, textile and pulp and paper industries and in fermentation of biomass into biofuels. Objective: The aim was to screen cellulase producing actinobacteria from the fruit orchard because of its requirement in several chemical reactions. Methods: Strains of actinobacteria were isolated on Sabouraud’s agar medium. Similarities in cultural and biochemical characterization by growing the strains on ISP medium and dissimilarities among them perpetuated to recognise nine groups of actinobacteria. Cellulase activity was measured by the diameter of clear zone around colonies on CMC agar and the amount of reducing sugar liberated from carboxymethyl cellulose in the supernatant of the CMC broth. Further, 16S rRNA gene sequencing and molecular characterization were placed before NCBI for obtaining recognition with accession numbers. Results: Prominent clear zones on spraying Congo Red were found around the cultures of strains of three groups SK703, SK706, SK708 on CMC agar plates. The enzyme assay for carboxymethylcellulase displayed extra cellulase activity in broth: 0.14, 0.82 and 0.66 µmol mL-1 min-1, respectively at optimum conditions of 35°C, pH 7.3 and 96 h of incubation. However, the specific cellulase activities per 1 mg of protein did not differ that way. It was 1.55, 1.71 and 1.83 μmol mL-1 min-1. The growing mycelia possessed short compact chains of 10-20 conidia on aerial branches. These morphological and biochemical characteristics, followed by their verification by Bergey’s Manual, categorically allowed the strains to be placed under actinobacteria. Further, 16S rRNA gene sequencing, molecular characterization and their evolutionary relationship through phylogenetics also confirmed the putative cellulase producing isolates of SK706 and SK708 subgroups to be the strains of Streptomyces. These strains on getting NCBI recognition were christened as Streptomyces glaucescens strain SK91L (KF527284) and Streptomyces rochei strain SK78L (KF515951), respectively. Conclusion: Conclusive evidence on the basis of different parameters established the presence of cellulase producing actinobacteria in the litchi orchard which can convert cellulose into fermentable sugar.

scholarly journals Association between 16S rRNA gene mutations and susceptibility to amikacin in Mycobacterium avium Complex and Mycobacterium abscessus clinical isolates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Su-Young Kim ◽  
Dae Hun Kim ◽  
Seong Mi Moon ◽  
Ju Yeun Song ◽  
Hee Jae Huh ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Mycobacterium Avium ◽  
Inhibitory Concentration ◽  
Gene Mutations ◽  
Mycobacterium Abscessus ◽  
Clinical Isolates ◽  
Rrna Gene ◽  
High Level ◽  
Culture Conversion

AbstractWe evaluated the association between 16S rRNA gene (rrs) mutations and susceptibility in clinical isolates of amikacin-resistant nontuberculous mycobacteria (NTM) in NTM-pulmonary disease (PD) patients. Susceptibility was retested for 134 amikacin-resistant isolates (minimum inhibitory concentration [MIC] ≥ 64 µg/ml) from 86 patients. Amikacin resistance was reconfirmed in 102 NTM isolates from 62 patients with either Mycobacterium avium complex-PD (MAC-PD) (n = 54) or M. abscessus-PD (n = 8). MICs and rrs mutations were evaluated for 318 single colonies from these isolates. For the 54 MAC-PD patients, rrs mutations were present in 34 isolates (63%), comprising all 31 isolates with amikacin MICs ≥ 128 µg/ml, but only three of 23 isolates with an MIC = 64 µg/ml. For the eight M. abscessus-PD patients, all amikacin-resistant (MIC ≥ 64 µg/ml) isolates had rrs mutations. In amikacin-resistant isolates, the A1408G mutation (n = 29) was most common. Two novel mutations, C1496T and T1498A, were also identified. The culture conversion rate did not differ by amikacin MIC. Overall, all high-level and 13% (3/23) of low-level amikacin-resistant MAC isolates had rrs mutations whereas mutations were present in all amikacin-resistant M. abscessus isolates. These findings are valuable for managing MAC- and M. abscessus-PD and suggest the importance of phenotypic and genotypic susceptibility testing.

scholarly journals In Vitro Effects of Doxycycline on Replication of Feline Coronavirus

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 312
Author(s):  
Magdalena Dunowska ◽  
Sayani Ghosh
Keyword(s):  
Inhibitory Concentration ◽  
Infectious Virus ◽  
Treatment Options ◽  
Inhibitory Effect ◽  
Virus Titration ◽  
Reverse Transcription Quantitative Pcr ◽  
In Vitro Effects ◽  
Dose Dependent ◽  
Feline Coronavirus

Feline infectious peritonitis (FIP) is a sporadic fatal disease of cats caused by a virulent variant of feline coronavirus (FCoV), referred to as FIP virus (FIPV). Treatment options are limited, and most of the affected cats die or are euthanized. Anecdotally, doxycycline has been used to treat FIP-affected cats, but there are currently no data to support or discourage such treatment. The aim of this study was to establish whether doxycycline inhibits replication of FIPV in vitro. The virus was cultured in Crandell-Rees feline kidney cells with various concentrations of doxycycline (0 to 50 µg/mL). The level of FIPV in cultures was determined by virus titration and FCoV-specific reverse-transcription quantitative PCR. Cell viability was also monitored. There was no difference in the level of infectious virus or viral RNA between doxycycline-treated and untreated cultures at 3, 12- and 18-hours post-infection. However, at 24 h, the growth of FIPV was inhibited by approximately two logs in cultures with >10 µg/mL doxycycline. This inhibition was dose-dependent, with inhibitory concentration 50% (IC50) 4.1 µg/mL and IC90 5.4 µg/mL. Our data suggest that doxycycline has some inhibitory effect on FIPV replication in vitro, which supports future clinical trials of its use for the treatment of FIP-affected cats.

Molecular characterization of the bacterial communities present in sheep's milk and cheese produced in South Brazilian Region via 16S rRNA gene metabarcoding sequencing

LWT ◽  
2021 ◽  
Vol 147 ◽  
pp. 111579
Author(s):  
Creciana M. Endres ◽  
Ícaro Maia S. Castro ◽  
Laura D. Trevisol ◽  
Juliana M. Severo ◽  
Michele B. Mann ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Molecular Characterization ◽  
Bacterial Communities ◽  
Rrna Gene

scholarly journals In Vitro α-Glucosidase and α-Amylase Inhibitory Activities of Free and Bound Phenolic Extracts from the Bran and Kernel Fractions of Five Sorghum Grain Genotypes

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1301
Author(s):  
Yun Xiong ◽  
Ken Ng ◽  
Pangzhen Zhang ◽  
Robyn Dorothy Warner ◽  
Shuibao Shen ◽  
...  
Keyword(s):  
Digestive System ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Phenolic Contents ◽  
Inhibitory Activities ◽  
Sorghum Grain ◽  
Global Health Challenge ◽  
Phenolic Extracts

Diabetes is a global health challenge. Currently, an effective treatment for diabetes is to reduce the postprandial hyperglycaemia by inhibiting the carbohydrate hydrolysing enzymes in the digestive system. In this study, we investigated the in vitro α-glucosidase and α-amylase inhibitory effects of free and bound phenolic extracts, from the bran and kernel fractions of five sorghum grain genotypes. The results showed that the inhibitory effect of sorghum phenolic extracts depended on the phenolic concentration and composition. Sorghum with higher phenolic contents generally had higher inhibitory activity. Among the tested extracts, the brown sorghum (IS131C)-bran-free extract (BR-bran-free, half-maximal inhibitory concentration (IC50) = 18 ± 11 mg sorghum/mL) showed the strongest inhibition against α-glucosidase which was comparable to that of acarbose (IC50 = 1.39 ± 0.23 mg acarbose/mL). The red sorghum (Mr-Buster)-kernel-bound extract (RM-kernel-bound, IC50 = 160 ± 12 mg sorghum/mL) was the most potent in inhibiting α-amylase but was much weaker compared to acarbose (IC50 = 0.50 ± 0.03 mg acarbose/mL).

scholarly journals Molecular Characterization of the CytochromebGene andIn VitroAtovaquone Susceptibility of Plasmodium falciparum Isolates from Kenya

2015 ◽  
Vol 59 (3) ◽  
pp. 1818-1821 ◽  
Author(s):  
Luicer A. Ingasia ◽  
Hoseah M. Akala ◽  
Mabel O. Imbuga ◽  
Benjamin H. Opot ◽  
Fredrick L. Eyase ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Genetic Polymorphism ◽  
Molecular Characterization ◽  
Mutant Allele ◽  
Inhibitory Concentration ◽  
Wild Type Allele ◽  
Wild Type ◽  
Western Kenya ◽  
Content Type

ABSTRACTThe prevalence of a genetic polymorphism(s) at codon 268 in the cytochromebgene, which is associated with failure of atovaquone-proguanil treatment, was analyzed in 227Plasmodium falciparumparasites from western Kenya. The prevalence of the wild-type allele was 63%, and that of the Y268S (denoting a Y-to-S change at position 268) mutant allele was 2%. There were no pure Y268C or Y268N mutant alleles, only mixtures of a mutant allele(s) with the wild type. There was a correlation between parasite 50% inhibitory concentration (IC50) and parasite genetic polymorphism; mutant alleles had higher IC50s than the wild type.

scholarly journals Enhanced Antibacterial Activity of Meropenem against Extensively Drug-Resistant Acinetobacter baumannii by Myrtaceae Plant Extracts

2020 ◽  
Vol 17 (11) ◽  
pp. 1168-1176
Author(s):  
Dennapa SAELOH ◽  
Monton VISUTTHI ◽  
Marisa LEEHA ◽  
Surasak LIMSUWAN ◽  
Supayang Piyawan VORAVUTHIKUNCHAI
Keyword(s):  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Drug Resistant ◽  
Microdilution Method ◽  
Extensively Drug Resistant ◽  
Resistant Phenotype ◽  
Bacterial Growth Inhibition ◽  
Mic Value

Acinetobacter baumannii (A. baumannii) has been known as a major cause of nosocomial bacterial infections worldwide. The bacteria are increasingly associated with a broad spectrum of antibiotic resistance, and this has become a widespread concern in a variety of hospitals.Antibiotic development and alternative treatment have become priorities for the treatment of bacterial infections.This study investigated the efficacy of meropenem in combination with five ethanolic extracts of plants in Myrtaceae against extensively drug-resistant (XDR) A. baumannii. The resistant phenotype was previously determined by microdilution method. XDR-A. baumannii strains showed resistance to meropenem with the minimum inhibitory concentration (MIC) in a range of 16 - 128 µg/mL, whereas the MIC value of all extracts, including Calistemon lancealatus, Eucalyptus citridora, Rhodomytus tomentasa, Syzygium cumini, and Xanthortemon chrysanthus, was over 1,000 µg/mL. Interestingly, all extracts potentiated the activity of the antibiotic by reducing the MIC values of the antibiotic. Xanthortemon chrysanthus extract displayed excellent synergism against the bacteria by decreasing the MIC value of the drug greater than 8-fold. In addition, the extract, at concentrations of 31.25, 62.5, 125, 250, 500, and 1,000 µg/mL, obviously increased the inhibitory effect of meropenem (1/4´MIC) against A. baumannii. The percentage of bacterial growth inhibition by combination was 87.9, 88.8, 91.8, 93.6, 99.9, and 100, respectively. The results supported that the extract could improve the activity of ineffective antibiotics against drug-resistant pathogens.Therefore, the findings may serve as therapeutic options for XDR-A. baumannii infections in the future.

scholarly journals Isolation and Characterization of a Novel p,p’-DDT-Degrading Bacterium: Aeromonas sp. Strain MY1 from Agricultural Soil

2020 ◽  
pp. 12-22
Author(s):  
Y. Murtala ◽  
B. C. Nwanguma ◽  
L. U. S. Ezeanyika
Keyword(s):  
Carbon Source ◽  
16S Rrna ◽  
Agricultural Soil ◽  
Sole Carbon Source ◽  
Phylogenetic Analyses ◽  
Inhibitory Effect ◽  
Aerobic Conditions ◽  
Degrading Bacterium ◽  
Isolation And Characterization

Background: Despite the banned on the use of dichlorodiphenyltrichloroethane (DDT) and other Persistent Organic Pollutants (POPs) by the Stockholm Convention for their toxicity, emerging shreds of evidence have indicated that DDT is, however, still in use in developing countries. This might increase the global burden of DDT contamination and its hazardous effects. Aim: This study focused on the isolation and characterization of p,p’-DDT-degrading bacterium from a tropical agricultural soil. Methodology: Standard isolation procedure was used for the screening and isolation of the strain. The 16S rRNA and phylogenetic analyses were used to identify the isolate and established protocols were followed to characterize the strain. Results: A new strain belonging to the genus Aeromonas was isolated from agricultural soil using minimal salt-p,p’-DDT enrichment medium. The 16S rRNA sequencing was used to identify the strain and the partial sequence was deposited in the NCBI GenBank as Aeromonas sp. Strain MY1. This mesophilic isolate was capable of utilizing up to 50 mgL-1 of p,p’-DDT as the sole carbon source at an optimum pH of 7.5 and optimum temperature of 35 °C within 120 h under aerobic conditions. Fe2+ (0.2 mgL-1) demonstrated a stimulatory effect on the p,p’-DDT degradation capacity by the strain MY1. However, Zn, Cu, Pb, Hg, Ag and Cr ions have demonstrated various patterns of inhibitory effect on the p,p’-DDT degradation capacity of the isolate at 0.2 mgL-1. The strain MY1 could be a promising candidate for the bioremediation of p,p’-DDT contaminant. Conclusion: Aeromonas sp. strain MY1 was capable of utilizing p,p’-DDT as a sole carbon source under aerobic conditions. The utilization capacity of the strain was influenced by some heavy metals. Fe was found to enhance the p,p’-DDT utilization capacity of the isolate at a lower concentration. While Zn, Cu, Pb, Hg, Ag and Cr showed various patterns of inhibitory effect.

scholarly journals Nisin and ε-poly-L-lysine as natural antimicrobials towards spoilage-associated Lactobacillus plantarum

2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Fernanda Cristina Kandalski Bortolotto ◽  
Maria Helena da Rosa Farfan ◽  
Nathalia Cristina Kleinke Jede ◽  
Gabriela Maia Danielski ◽  
Renata Ernlund Freitas de Macedo
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Minimal Bactericidal Concentration ◽  
Natural Antimicrobials ◽  
Food Preservatives ◽  
Spoilage Bacteria ◽  
Mass Spectrometry Identification

ABSTRACT: Sausages are highly susceptible to microbial spoilage. Lactic acid bacteria (LAB) is the main group of spoilage bacteria in vacuum packed cooked sausages. To control microbial growth natural antimicrobials have been used as food preservatives. The aim of this study was to identify strains of lactic acid bacteria isolated from spoiled commercial Calabresa sausages and use them in an in vitro challenge with the natural antimicrobials, nisin (NI) and ε-poly-L-lysine (ε-PL). Mass spectrometry identification of LAB isolated from sausages using MALDI-TOF revealed a predominance of L. plantarum in the LAB population. RAPD-PCR of L. plantarum strains showed four different genetic profiles. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of NI and ε-PL, alone and in combination, against a pool of different profiles L. plantarum were determined. MIC of NI and ε-PL were 0.468 mg/ L and 75 mg/ L; respectively, whereas MBC of NI and ε-PL were 12.48 mg/L and 150 mg/L, respectively. The combined effect of NI and ε-PL was determined using concentrations at 1/4 and 1/8 of individual MICs. Synergistic effect was confirmed at both concentrations showing a fractional inhibitory concentration index of 0.5 and 0.2, respectively. The combination of NI and ε-PL at a small concentration of 0.05 mg/L and 9.375 mg/L, respectively, showed inhibitory effect towards spoilage L. plantarum Results show the potential of the combined use of NI and ε-PL to control sausage spoilage-associated with lactobacilli.

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