Biochemical and molecular characterization of proteolytic bacterial strains isolated from Jazan region, KSA with the application as an antibacterial agent

2020 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Bander Mohammed Al-Thobaiti ◽  
Emad Abada ◽  
Khaled El-Gayar

Objectives: Biochemical and molecular characterization of proteolytic bacterial strains isolated from Jazan region, KSA with the application as an antibacterial agent. Materials and Methods: Three samples were collected from extreme environment, Jazan, KSA. Skim milk nutrient agar medium was used for protease screening for several colonies by streaking method at 37°C. API biochemical kit was used to characterize the three isolates using some selective media. The genetic identification was done using 16S rRNA gene sequencing. The sensitivity of the tested strains;Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae against the extracellular crude protease enzyme produced from the three isolated bacteria and different antibiotics was done. Results: The isolates were identified as Bacillus subtilis, Bacillus licheniformis, and Bacillus cereus. B. cereus and B. licheniformis recorded high sensitivity (71%) against most antibiotics, in addition, B. subtilis showed resistance to Aztreonam only. It was found a considerable increase in the level of both of protease activity (units/ml) and bacterial growth (colony-forming units/ml) of the cultures that were directed by the B. subtilis and B. licheniformis up to 37°C then decreased at 45°C. On the contrary, the growth of B. cereus and its activity gradually increased up to 45°C. The enzyme activity and bacterial growth of B. subtilis and B. cereus strains were increased at alkaline medium. However, B. licheniformis gave the highest growth and activity at neutral pH. In addition, it was found that the enzyme activity and bacterial growth of B. subtilis were reached to the maximum at 5% NaCl. However, the maximum bacterial growth and enzyme activity for B. licheniformis and B. cereus was at 2% NaCl. It was found high effect on inhibiting the growth of pathogenic bacteria using 5 μl of crude enzyme with specific enzyme activity 73, 76, and 92 (units/ml)/(mg protein/ml) for B. subtilis, B. licheniformis, and B. cereus, respectively. All pathogenic bacteria were totally inhibited with 10 μl of crude enzyme. Conclusion: The potential Bacillus proteases can promote new industry as antimicrobial agents.

2019 ◽  
Vol 2 (4) ◽  
pp. 91
Author(s):  
Lal Krishna

The study was aimed at identification, production and characterization of nattokinase, bacteriocin from bacterial species. Nattokinase and bacteriocins finds a wide range of applications in Pharmaceutical industry, health care and medicine. Nattokinase is a highly active fibrinolytic enzyme secreted by Bacillus subtilis and bacteriocins are proteinaceous toxins produced by Lactobacillus to inhibit the growth of closely related bacterial strains. Bacillus subtilis and Lactobacillus isolates shown positive results to microscopic, biochemical analysis.  The nattokinase and bacteriocins were produced by optimizing the media. The enzymes were purified by ammonium sulfate precipitation and HPLC. The enzyme activity for nattokinase was found at 7 mg/ml, pH 8.0 and temperature 48 ºC and the enzyme activity for bacteriocin was found at 3.9 mg/ml, pH 6.5 and temperature 30 °C. Bacteriocins from Lactobacillus showed good antagonistic activity against pathogenic bacteria. Nattokinase from Bacillus subtilis played a significant role in thrombolytic and anti-coagulation at in vitro. The results indicated that the pure enzyme has a potential in dissolving blood clot.


2012 ◽  
Vol 64 (3) ◽  
pp. 877-883
Author(s):  
S. Tasic ◽  
M. Kojic ◽  
S. Stankovic ◽  
D. Obradovic

The isolation and molecular characterization of bacterial strains isolated from water sources in the Vlasina Mountain in southeast Serbia, confirmed the presence of a new species Chryseobacterium vrystaatense ST1. This Gram- negative species showed an extremely low level of biochemical reactivity in biochemical tests. The gene for 16S rRNA was amplified by PCR using universal primers and sequenced. Comparison of 16S rRNA gene sequence and phenotypic features indicated that the isolate ST belonged to Chryseobacterium vrystaatense. A BLAST search of sequenced 1088 nucleotides of the 16S rRNA gene with all sequences deposited in the NCBI collection showed the highest similarity (98%) with the strain Chryseobacterium vrystaatense sp. nov., designated as strain R-23533. The very high homology of these two strains allowed classification of our strain at the species level, but some differences indicate, and indirectly confirm, that the isolate ST is an authentic representative. On the basis of these results, we could conclude that Chryseobacterium vrystaatense ST was for first time isolated in Serbia, which is particularly important when one bears in mind that there are only three sequences of this species deposited in the NCBI collection.


LWT ◽  
2021 ◽  
Vol 147 ◽  
pp. 111579
Author(s):  
Creciana M. Endres ◽  
Ícaro Maia S. Castro ◽  
Laura D. Trevisol ◽  
Juliana M. Severo ◽  
Michele B. Mann ◽  
...  

2020 ◽  
Vol 57 (2) ◽  
pp. 179-184
Author(s):  
P. F. Barradas ◽  
A. R. Flores ◽  
T. L. Mateus ◽  
F. Carvalho ◽  
F. Gärtner ◽  
...  

SummaryCrenosoma striatum is a host-specifi c metastrongiloid nematode causing respiratory tract disease in hedgehogs (Erinaceus europaeus). Since few studies have reported C. striatum in hedgehogs and little genetic data is available concerning this lungworm, this study aimed to determine the occurrence of C. striatum in a population sample of hedgehogs from Portugal, additionally providing morphological, histological and molecular data. From 2017 to 2018 a survey of infection was carried out in 11 necropsied hedgehogs. Worms were extracted from fresh lung tissues and microscopically evaluated. Molecular characterization of partial mitochondrial (12S rRNA) and nuclear (18S rRNA) genes was performed. The presence of lungworms in pulmonary tissues of five hedgehogs (45.5%) was detected. Morphological and histopathological analyses evidenced adult forms of nematodes consistent with C. striatum. Molecular characterization of 18S rRNA genes confirmed the classifi cation as C. striatum. Also, novel genetic data characterizing the mitochondrial (12S rRNA) gene of C. striatum is presented.This is the first report of C. striatum infection in hedgehogs of Portugal. The findings here reported provide new insights regarding the geographic distribution and the molecular identification of this lungworm species.


2018 ◽  
Vol 10 (3) ◽  
pp. 546-552
Author(s):  
Maria Yasinta Moi ◽  
Endang Kusdiyantini ◽  
Sri Pujiyanto

Endophytic bacteria isolated from some various kind of plants are able to yield some active compounds which have a role as an antibacterial compound. This work aimed to isolate and to screen the Endophytic bacteria from Faloak seed in its charge in inhibiting two kinds of pathogenic bacteria, Staphylococcus aureus and Escherichia coli. There were six isolates of Endophytic bacteria isolated in this work. According to the screening result, one isolate which had the most potential antibacterial activity (marked by the formation of inhibition zone) against S. aureus and E. coli. That most potential isolate was then tested and identified for both biochemical properties and molecular 16S rRNA gene. The result of this study showed that the endophytic bacteria isolate of Faloak seed with the code of S1 had the similarity with Enterobacter xiangfangensis strain 10-17 by 93 %. The research about endophytic bacteria of Faloak plants was never conducted before. Thus this research was expected to give information about the potential of antimicrobial ability Faloak plants which can be utilized in the discovery of new antibiotic compounds which in the future are expected to overcome the problem of microorganism resistance to antibiotics. The use of endophytic bacteria is expected to prevents the extinction of Faloak plants due to excessive use.


2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Irene Cano ◽  
Ronny van Aerle ◽  
Stuart Ross ◽  
David W. Verner-Jeffreys ◽  
Richard K. Paley ◽  
...  

ABSTRACTOne of the fastest growing fisheries in the UK is the king scallop (Pecten maximusL.), also currently rated as the second most valuable fishery. Mass mortality events in scallops have been reported worldwide, often with the causative agent(s) remaining uncharacterized. In May 2013 and 2014, two mass mortality events affecting king scallops were recorded in the Lyme Bay marine protected area (MPA) in Southwest England. Histopathological examination showed gill epithelial tissues infected with intracellular microcolonies (IMCs) of bacteria resemblingRickettsia-like organisms (RLOs), often with bacteria released in vascular spaces. Large colonies were associated with cellular and tissue disruption of the gills. Ultrastructural examination confirmed the intracellular location of these organisms in affected epithelial cells. The 16S rRNA gene sequences of the putative IMCs obtained from infected king scallop gill samples, collected from both mortality events, were identical and had a 99.4% identity to 16S rRNA gene sequences obtained from “CandidatusEndonucleobacter bathymodioli” and 95% withEndozoicomonasspecies.In situhybridization assays using 16S rRNA gene probes confirmed the presence of the sequenced IMC gene in the gill tissues. Additional DNA sequences of the bacterium were obtained using high-throughput (Illumina) sequencing, and bioinformatic analysis identified over 1,000 genes with high similarity to protein sequences fromEndozoicomonasspp. (ranging from 77 to 87% identity). Specific PCR assays were developed and applied to screen for the presence of IMC 16S rRNA gene sequences in king scallop gill tissues collected at the Lyme Bay MPA during 2015 and 2016. There was 100% prevalence of the IMCs in these gill tissues, and the 16S rRNA gene sequences identified were identical to the sequence found during the previous mortality event.IMPORTANCEMolluscan mass mortalities associated with IMCs have been reported worldwide for many years; however, apart from histological and ultrastructural characterization, characterization of the etiological agents is limited. In the present work, we provide detailed molecular characterization of anEndozoicomonas-like organism (ELO) associated with an important commercial scallop species.


Plant Disease ◽  
2020 ◽  
Vol 104 (6) ◽  
pp. 1601-1609
Author(s):  
Peng Cao ◽  
Chenxu Li ◽  
Kefei Tan ◽  
Chuanzeng Liu ◽  
Xi Xu ◽  
...  

Rice is used as a staple food in different areas of world, especially in China. In recent years, rice seedlings have been affected seriously by symptoms resembling bacterial palea browning (BPB) in Heilongjiang Province. To isolate and identify the pathogenic bacteria responsible for the disease, 40 bacterial strains were isolated from diseased rice seedlings collected from the four major accumulative-temperature zones of rice fields cultivated in Heilongjiang Province, and these were identified as 13 species based on morphological characteristics and 16S ribosomal RNA (rRNA) gene sequences. Inoculation of all the isolates on healthy rice seedlings showed that the nine Enterobacter cloacae isolates were the pathogens causing typical symptoms of BPB, including yellowing to pale browning, stunting, withering, drying, and death. Moreover, the nine E. cloacae isolates could also cause symptoms of bacterial disease on the seedlings of soybean (Glycine max), maize (Zea mays L.), and tomato (Solanum lycopersicum). Phylogenetic analysis based on the 16S rRNA gene sequences and phenotypic and biochemical characteristics indicated that these nine pathogenic isolates were E. cloacae. In addition, analysis of the sequences of four housekeeping genes (rpoB, gyrB, infB, and atpD) from the selected strain SD4L also assigned the strain to E. cloacae. Therefore, E. cloacae is the pathogen causing disease of rice seedlings in Heilongjiang Province, which we propose to classify as a form of BPB. To the best of our knowledge, this is the first study to identify E. cloacae as a causal agent of BPB in rice.


2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Elisa Steiner ◽  
Rosa Margesin

Abstract Purpose To evaluate the production of a cold-active CMCase (endoglucanase) by Bacillus mycoides AR20-61 isolated from Alpine forest soil and to characterize the crude enzyme. Methods After studying the effect of cultivation parameters (medium composition, temperature, NaCl concentration, pH) on bacterial growth and enzyme production, the crude enzyme was characterized with regard to the effect of pH, temperature, and inhibitors on enzyme activity and stability. Result Optimum growth and enzyme production occurred at 20–25 °C, pH 7, and 1–1.5% (w/v) CMC. Despite high biomass production over the whole growth temperature range (10–35 °C), enzyme production was low at 10 and 35 °C. CMC concentration had a minor effect on growth, independent of the growth temperature, but a significant effect on CMCase production at temperatures ≥ 20 °C. The crude enzyme was active over a broad temperature range (0–60 °C); the apparent optimum temperature for activity was at 40–50 °C. The cultivation temperature influenced the effect of temperature on enzyme activity and stability. A significantly higher thermosensitivity of the enzyme produced at a cultivation temperature of 10 °C compared to that produced at 25 °C was noted at 50 and 65 °C. The enzyme was highly active over a pH range of 4–6 and showed optimum activity at pH 5. No activity was lost after 60 min of incubation at 30 °C and pH 4–9. The CMCase was resistant against a number of monovalent and divalent metal ions, metal-chelating agents, and phenol. Conclusion The CMCase produced by the studied strain is characterized by high activities in the low temperature range (down to 0 °C) and acidic pH range, high stability over a broad pH range, and high resistance against a number of effectors. Our results also demonstrate the different, independent roles of temperature in bacterial growth, enzyme production, nutrient requirements during enzyme production, and enzyme characteristics regarding thermosensitivity, which has not yet been described for cellulases.


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