scholarly journals Cytogenetic Study on Mitotic Cell Division in Allium cepa by Lead (Pb) and Chromium (Cr) Containing Bacterial Strain Isolated from Tannery Effluents of Bangladesh

2021 ◽  
Vol 2 (2) ◽  
pp. 084-090
Author(s):  
Afrin Priya Talukder ◽  
Sarwat Tazrian ◽  
Md. Nazmul Haque ◽  
Shahriar Zaman ◽  
Md. Akhtar-E-Ekram

In the present study, a bacterial strain capable of Pb and Cr detoxification was isolated from tannery effluents which was identified as Myroides sp. through 16S rRNA gene sequencing. In the cytogenetic experiment, 100 and 600 µg/ml of lead and chromium were used as treatment for the root tips of Allium cepa and caused many chromosomal abnormalities such as abnormal chromosome position, damaged nucleus, breaks of chromosome bridges and fragments also occurred. Notably, sticky metaphase was found where sticky chromosomes indicated highly toxic, usually irreversible consequences leading to cell death. However, Myroides sp. treated supernatant, collected after day 7, used to treat Allium cepa tips showed less mitotic aberrations, nuclear degeneration and observed normal anaphase and telophase stage indicating possible metal detoxifying ability of the isolated strain. Furthermore, LC50 value was 64.63 μl/ml for Myroides sp.

2020 ◽  
Vol 17 (3) ◽  
pp. 41-50
Author(s):  
Allison Grodnick ◽  
Ashley Fink ◽  
Timothy Johnson ◽  
David Mitchell

As an unintentional result of the extensive use of antibiotics in healthcare and agriculture, antibiotics have become an increasingly prevalent selective pressure on bacteria. This forces bacteria to evolve and acquire antibiotic-resistant genes or mutations in order to survive. Suppose a bacterial strain acquires resistance to three or more antibiotics. In that case, it is deemed multidrug-resistant (MDR), and it becomes a potentially more serious problem to solve in the context of healthcare. This study aims to evaluate the acquisition of resistance to multiple antibiotic drugs by an initially susceptible isolated bacterium from a Minnesota forest environment. The bacterium was found to be Pseudomonas by 16s rRNA gene sequencing. Three antibiotics, neomycin, ciprofloxacin, and imipenem, each from a different drug class, were selected to see if this isolate could become resistant over time and exposure. The bacterial strain developed resistance to the selected antibiotics through a series of sequential exposures to increasing concentrations of each drug in this order. As determined by a disc susceptibility test, the initial isolate acquired resistance to all three selected antibiotics. Single nucleotide polymorphisms (SNPs) between the original isolate and the final resistant strain were identified. These SNPs suggest that mutations to efflux transporters and antibiotic protein targets play a role in acquiring and maintaining antibiotic resistance. KEYWORDS: Multidrug Resistance; Antibiotics; Neomycin; Ciprofloxacin; Imipenem; Pseudomonas; Evolution; MDR; Minnesota Environment


2019 ◽  
Vol 11 (2) ◽  
pp. 486-491
Author(s):  
V. Sridevi ◽  
M. Raghuram

Sugar industrial effluents possess high amounts of toxic pollutants and contaminate the receiving sites. Treatment of contaminated sites by using microorganisms provides an alternate to conventional methods hence demands in the identification of metal tolerant microorganisms has been increasing day by day. Therefore in this study soil samples collected from Tanuku sugar factory residual effluent point (bank of Gosthani river), west Godavari district A.P were analyzed for the bacterial tolerance to Copper (Cu), Zinc (Zn) and Lead (Pb) in their chloride forms. Additionally, the study was carried out to identify the metal tolerant bacteria by morphological, biochemical and 16S rRNA gene sequencing studies. Four potential bacterial isolates were selected to analyze metal tolerance against CuCl2, ZnCl2, and PbCl2. The sequences were compared with those in NCBI and submitted in gene bank with accession numbers MK100333 (Paenibacillus cookie), MK100334 (Bacillus cereus), MK100335 (Aneurini bacillus sp) and MK100387 (Paenibacillus sp.). A Phylogenetic tree was constructed to Paenibacillus sp. the highly efficient bacterial strain among the four isolates using MEGA 7 soft ware. The results of this study showed that P. dentritiformis had multiple metal tolerances (Cu, Zn and Pb) up to 500mg/L after 72 hrs.  The identified bacterial strain proved to be the strong heavy metal tolerant bacterial strain. Hence, its usage will be helpful in the treatment of heavy metals specifically Cu, Zn and Pb contaminated soils and further optimization of these cultures is required to improve its metal resistant capacity.


2019 ◽  
Vol 13 (1) ◽  
pp. 90-101
Author(s):  
Sanju Kumari ◽  
Utkarshini Sharma ◽  
Rohit Krishna ◽  
Kanak Sinha ◽  
Santosh Kumar

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.


Life ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 254
Author(s):  
Ying Wang ◽  
Jianqing Zhu ◽  
Jie Fang ◽  
Li Shen ◽  
Shuojia Ma ◽  
...  

We characterized the gut microbial composition and relative abundance of gut bacteria in the larvae and adults of Pieris canidia by 16S rRNA gene sequencing. The gut microbiota structure was similar across the life stages and sexes. The comparative functional analysis on P. canidia bacterial communities with PICRUSt showed the enrichment of several pathways including those for energy metabolism, immune system, digestive system, xenobiotics biodegradation, transport, cell growth and death. The parameters often used as a proxy of insect fitness (development time, pupation rate, emergence rate, adult survival rate and weight of 5th instars larvae) showed a significant difference between treatment group and untreated group and point to potential fitness advantages with the gut microbiomes in P. canidia. These data provide an overall view of the bacterial community across the life stages and sexes in P. canidia.


Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Janis R. Bedarf ◽  
Naiara Beraza ◽  
Hassan Khazneh ◽  
Ezgi Özkurt ◽  
David Baker ◽  
...  

Abstract Background Recent studies suggested the existence of (poly-)microbial infections in human brains. These have been described either as putative pathogens linked to the neuro-inflammatory changes seen in Parkinson’s disease (PD) and Alzheimer’s disease (AD) or as a “brain microbiome” in the context of healthy patients’ brain samples. Methods Using 16S rRNA gene sequencing, we tested the hypothesis that there is a bacterial brain microbiome. We evaluated brain samples from healthy human subjects and individuals suffering from PD (olfactory bulb and pre-frontal cortex), as well as murine brains. In line with state-of-the-art recommendations, we included several negative and positive controls in our analysis and estimated total bacterial biomass by 16S rRNA gene qPCR. Results Amplicon sequencing did detect bacterial signals in both human and murine samples, but estimated bacterial biomass was extremely low in all samples. Stringent reanalyses implied bacterial signals being explained by a combination of exogenous DNA contamination (54.8%) and false positive amplification of host DNA (34.2%, off-target amplicons). Several seemingly brain-enriched microbes in our dataset turned out to be false-positive signals upon closer examination. We identified off-target amplification as a major confounding factor in low-bacterial/high-host-DNA scenarios. These amplified human or mouse DNA sequences were clustered and falsely assigned to bacterial taxa in the majority of tested amplicon sequencing pipelines. Off-target amplicons seemed to be related to the tissue’s sterility and could also be found in independent brain 16S rRNA gene sequences. Conclusions Taxonomic signals obtained from (extremely) low biomass samples by 16S rRNA gene sequencing must be scrutinized closely to exclude the possibility of off-target amplifications, amplicons that can only appear enriched in biological samples, but are sometimes assigned to bacterial taxa. Sequences must be explicitly matched against any possible background genomes present in large quantities (i.e., the host genome). Using close scrutiny in our approach, we find no evidence supporting the hypothetical presence of either a brain microbiome or a bacterial infection in PD brains.


2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Musa Saheed Ibrahim ◽  
Beckley Ikhajiagbe

Abstract Background Rice forms a significant portion of food consumed in most household worldwide. Rice production has been hampered by soil factors such as ferruginousity which has limited phosphorus availability; an important mineral component for the growth and yield of rice. The presence of phosphate-solubilizing bacteria (PSB) in soils has been reported to enhance phosphate availability. In view of this, the present study employed three bacteria species (BCAC2, EMBF2 and BCAF1) that were previously isolated and proved P solubilization capacities as inocula to investigate the growth response of rice germinants in an in vitro setup. The bacteria isolates were first identified using 16S rRNA gene sequencing and then applied as inoculum. The inolula were prepared in three concentrations (10, 7.5 and 5.0 ml) following McFarland standard. Viable rice (var. FARO 44) seeds were sown in petri dishes and then inoculated with the three inocula at the different concentrations. The setup was studied for 28 days. Results 16S rRNA gene sequencing identified the isolates as: isolate BCAC2= Bacillus cereus strain GGBSU-1, isolate BCAF1= Proteus mirabilis strain TL14-1 and isolate EMBF2= Klebsiella variicola strain AUH-KAM-9. Significant improvement in rice germination, morphology, physiology and biomass parameters in the bacteria-inoculated setups was observed compared to the control. Germination percentage after 4 days was 100 % in the inoculated rice germinants compared to 65% in the control (NiS). Similarly, inoculation with the test isolates enhanced water-use efficiency by over 40%. The rice seedlings inoculated with Bacillus cereus strain GGBSU-1 (BiS) showed no signs of chlorosis and necrosis throughout the study period as against those inoculated with Proteus mirabilis strain TL14-1 (PiS) and Klebsiella variicola strain AUH-KAM-9 (KiS). Significant increase in chlorophyll-a, chlorophyll-b and alpha amylase was observed in the rice seedlings inoculated with BiS as against the NiS. Conclusion Inoculating rice seeds with Bacillus cereus strain GGBSU-1, Proteus mirabilis strain TL14-1 and Klebsiella variicola strain AUH-KAM-9 in an in vitro media significantly improved growth parameters of the test plant. Bacillus cereus strain GGBSU-1 showed higher efficiency due to a more improved growth properties observed.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vanessa Palmas ◽  
Silvia Pisanu ◽  
Veronica Madau ◽  
Emanuela Casula ◽  
Andrea Deledda ◽  
...  

AbstractIn the present study, we characterized the distinctive signatures of the gut microbiota (GM) from overweight/obese patients (OB), and normal-weight controls (NW), both of Sardinian origin. Fecal bacterial composition of 46 OB patients (BMI = 36.6 ± 6.0; F/M = 40/6) was analyzed and compared to that of 46 NW subjects (BMI = 21.6 ± 2.1; F/M = 41/5), matched for sex, age and smoking status, by using 16S rRNA gene sequencing on MiSeq Illumina platform. The gut microbial community of OB patients exhibited a significant decrease in the relative abundance of several Bacteroidetes taxa (i.e. Flavobacteriaceae, Porphyromonadaceae, Sphingobacteriaceae, Flavobacterium, Rikenella spp., Pedobacter spp., Parabacteroides spp., Bacteroides spp.) when compared to NW; instead, several Firmicutes taxa were significantly increased in the same subjects (Lachnospiraceae, Gemellaceae, Paenibacillaceae, Streptococcaceae, Thermicanaceae, Gemella, Mitsuokella, Streptococcus, Acidaminococcus spp., Eubacterium spp., Ruminococcus spp., Megamonas spp., Streptococcus, Thermicanus, Megasphaera spp. and Veillonella spp.). Correlation analysis indicated that body fatness and waist circumference negatively correlated with Bacteroidetes taxa, while Firmicutes taxa positively correlated with body fat and negatively with muscle mass and/or physical activity level. Furthermore, the relative abundance of several bacterial taxa belonging to Enterobacteriaceae family, known to exhibit endotoxic activity, was increased in the OB group compared to NW. The results extend our knowledge on the GM profiles in Italian OB, identifying novel taxa linking obesity and intestine.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Shenhai Gong ◽  
Yinglin Feng ◽  
Yunong Zeng ◽  
Huanrui Zhang ◽  
Meiping Pan ◽  
...  

Abstract Background Gut microbiota has been reported to be disrupted by cisplatin, as well as to modulate chemotherapy toxicity. However, the precise role of intestinal microbiota in the pathogenesis of cisplatin hepatotoxicity remains unknown. Methods We compared the composition and function of gut microbiota between mice treated with and without cisplatin using 16S rRNA gene sequencing and via metabolomic analysis. For understanding the causative relationship between gut dysbiosis and cisplatin hepatotoxicity, antibiotics were administered to deplete gut microbiota and faecal microbiota transplantation (FMT) was performed before cisplatin treatment. Results 16S rRNA gene sequencing and metabolomic analysis showed that cisplatin administration caused gut microbiota dysbiosis in mice. Gut microbiota ablation by antibiotic exposure protected against the hepatotoxicity induced by cisplatin. Interestingly, mice treated with antibiotics dampened the mitogen-activated protein kinase pathway activation and promoted nuclear factor erythroid 2-related factor 2 nuclear translocation, resulting in decreased levels of both inflammation and oxidative stress in the liver. FMT also confirmed the role of microbiota in individual susceptibility to cisplatin-induced hepatotoxicity. Conclusions This study elucidated the mechanism by which gut microbiota mediates cisplatin hepatotoxicity through enhanced inflammatory response and oxidative stress. This knowledge may help develop novel therapeutic approaches that involve targeting the composition and metabolites of microbiota.


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