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Journal, Genetic Engineering &... Jan 2022Lignin is a complex polymer of phenyl propanoid units found in the vascular tissues of the plants as one of lignocellulose materials. Many bacteria secrete enzymes to...
BACKGROUND
Lignin is a complex polymer of phenyl propanoid units found in the vascular tissues of the plants as one of lignocellulose materials. Many bacteria secrete enzymes to lyse lignin, which can be essential to ease the production of bioethanol. Current research focused on the study of ligninolytic bacteria capable of producing lignin peroxidase (LiP) which can help in lignin biodegradation and bioethanol production. Ligninolytic bacterial strains were isolated and screened from the soil samples of Simlipal Biosphere Reserve (SBR), Odisha (India), for the determination of their LiP activity. Enzymatic assay and optimization for the LiP activity were performed with the most potent bacterial strain. The strain was identified by morphological, biochemical, and molecular methods.
RESULTS
In this study, a total of 16 bacteria (Simlipal ligninolytic bacteria [SLB] 1-16) were isolated from forest soils of SBR using minimal salt medium containing lignin. Out of the 16 isolates, 9 isolates showed decolourization of methylene blue dye on LB agar plates. The bacterial isolates such as SLB8, SLB9, and SLB10 were able to decolourize lignin with 15.51%, 16.80%, and 33.02%, respectively. Further enzyme assay was performed using HO as substrate and methylene blue as an indicator for these three bacterial strains in lignin containing minimal salt medium where the isolate SLB10 showed the highest LiP activity (31.711 U/mg). The most potent strain, SLB10, was optimized for enhanced LiP enzyme activity using response surface methodology. In the optimized condition of pH 10.5, temperature 30 °C, HO concentration 0.115 mM, and time 42 h, SLB10 showed a maximum LiP activity of 55.947 U/mg with an increase of 1.76 times from un-optimized condition. Further chemical optimization was performed, and maximum LiP activity as well as significant dye-decolourization efficiency of SLB10 has been found in bacterial growth medium supplemented individually with cellulose, yeast extract, and MnSO. Most notably, yeast extract and MnSO-supplemented bacterial culture medium were shown to have even higher percentage of dye decolourization compared to normal basal medium. The bacterial strain SLB10 was identified as Bacillus mycoides according to morphological, biochemical, and molecular (16S rRNA sequencing) characterization and phylogenetic tree analysis.
CONCLUSION
Result from the present study revealed the potential of Bacillus mycoides bacterium isolated from the forest soil of SBR in producing LiP enzyme that can be evaluated further for application in lignin biodegradation and bioethanol production. Scaling up of LiP production from this potent bacterial strain could be useful in different industrial applications.
PubMed: 34978643
DOI: 10.1186/s43141-021-00284-2 -
PeerJ 2020Bacterial biofilms have become a major threat to human health. The objective of this study was to isolate amylase-producing bacteria from soil to determine the overall...
BACKGROUND
Bacterial biofilms have become a major threat to human health. The objective of this study was to isolate amylase-producing bacteria from soil to determine the overall inhibition of certain pathogenic bacterial biofilms.
METHODS
We used serial dilution and the streaking method to obtain a total of 75 positive amylase isolates. The starch-agar plate method was used to screen the amylolytic activities of these isolates, and we used morphological and biochemical methods to characterize the isolates. Optimal conditions for amylase production and purification using Sephadex G-200 and SDS-PAGE were monitored. We screened these isolates' antagonistic activities and the purified amylase against pathogenic and multi-drug-resistant human bacteria using the agar disk diffusion method. Some standard antibiotics were controlled according to their degree of sensitivity. Finally, we used spectrophotometric methods to screen the antibiofilm 24 and 48 h after application of filtering and purifying enzymes in order to determine its efficacy at human pathogenic bacteria.
RESULTS
The isolated species were (26.7%), (16%), (13.3%), (10.7%), (10.7%), (5.3%), (5.3%), (4%), (4%), and (4%). Interestingly, all isolates showed a high antagonism to target pathogens. had the highest recorded activity (48 mm) and had the lowest recorded activity (12 mm) against (MRSA) and , respectively. On the other hand, we detected no antibacterial activity for purified amylase. The supernatant of the isolated amylase-producing bacteria and its purified amylase showed significant inhibition for biofilm: 93.7% and 78.8%, respectively. This suggests that supernatant and purified amylase may be effective for clinical and environmental biofilm control.
DISCUSSION
Our results showed that soil bacterial isolates such as supernatant and its purified amylase are good antibiofilm tools that can inhibit multidrug-resistant former strains. They could be beneficial for pharmaceutical use. While purified amylase was effective as an antibiofilm, the isolated supernatant showed better results.
PubMed: 33194439
DOI: 10.7717/peerj.10288 -
MSphere Nov 2020Gram-positive, spore-forming members of the group species complex are widespread in natural environments and display various degrees of pathogenicity. Recently, group...
Gram-positive, spore-forming members of the group species complex are widespread in natural environments and display various degrees of pathogenicity. Recently, group strain Flugge ATCC 21929 was found to represent a novel lineage within the species complex, sharing a relatively low degree of genomic similarity with all group genomes (average nucleotide identity [ANI] < 88). ATCC 21929 has been previously associated with the production of a patented antibiotic, antibiotic 60-6 (i.e., cerexin A); however, the virulence potential and growth characteristics of this lineage have never been assessed. Here, we provide an extensive genomic and phenotypic characterization of ATCC 21929, and we assess its pathogenic potential ATCC 21929 most closely resembles NH24A2 (ANI and DNA-DNA hybridization values of 86.70 and 34.10%, respectively). Phenotypically, ATCC 21929 does not possess cytochrome oxidase activity and is able to grow at a range of temperatures between 15 and 43°C and a range of pH between 6 and 9. At 32°C, ATCC 21929 shows weak production of diarrheal enterotoxin hemolysin BL (Hbl) but no production of nonhemolytic enterotoxin (Nhe); at 37°C, neither Hbl nor Nhe is produced. Additionally, at 37°C, ATCC 21929 does not exhibit cytotoxic effects toward HeLa cells. With regard to fatty acid composition, ATCC 21929 has iso-C17:0 present in highest abundance. Based on the characterization provided here, ATCC 21929 (= PS00077A = PS00077B = PSU-0922 = BHP) represents a novel effective group species, which we propose as effective species "" The group comprises numerous closely related lineages with various degrees of pathogenic potential and industrial relevance. Species-level taxonomic classification of group strains is important for risk evaluation and communication but remains challenging. Biochemical and phenotypic assays are often used to assign group strains to species but are insufficient for accurate taxonomic classification on a genomic scale. Here, we show that antibiotic-producing ATCC 21929 represents a novel lineage within the group that, by all metrics used to delineate prokaryotic species, exemplifies a novel effective species. Furthermore, we show that ATCC 21929 is incapable of producing enterotoxins Hbl and Nhe or exhibiting cytotoxic effects on HeLa cells at human body temperature These results provide greater insight into the genomic and phenotypic diversity of the group and may be leveraged to inform future public health and food safety efforts.
Topics: Anti-Bacterial Agents; Bacillus cereus; Genome, Bacterial; HeLa Cells; Humans; Phylogeny; Soil Microbiology
PubMed: 33148822
DOI: 10.1128/mSphere.00882-20 -
Brazilian Journal of Microbiology :... 2014In this paper, the production of humic substances (HS) through the bacterial solubilization of low rank coal (LRC) was evaluated. The evaluation was carried out by 19...
In this paper, the production of humic substances (HS) through the bacterial solubilization of low rank coal (LRC) was evaluated. The evaluation was carried out by 19 bacterial strains isolated in microenvironments with high contents of coal wastes. The biotransformed LRC and the HS produced were quantified in vitro in a liquid growth medium. The humic acids (HA) obtained from the most active bacterial strain were characterized via elemental composition (C, H, N, O), IR analyses, and the E4/E6 ratio; they were then compared with the HA extracted chemically using NaOH. There was LRC biotransformation ranged from 25 to 37%, and HS production ranged from 127 to 3100 mg . L(-1). More activity was detected in the isolated strains of Bacillus mycoides, Microbacterium sp, Acinetobacter sp, and Enterobacter aerogenes. The HA produced by B. mycoides had an IR spectrum and an E4/E6 ratio similar to those of the HA extracted with NAOH, but their elemental composition and their degree of aromatic condensation was different. Results suggest that these bacteria can be used to exploit the LRC resulting from coal mining activities and thus produce HS in order to improve the content of humified organic matter in soils.
Topics: Bacteria; Biotransformation; Coal; Elements; Environmental Microbiology; Humic Substances
PubMed: 25477925
DOI: 10.1590/s1517-83822014000300021 -
Frontiers in Microbiology 2020Flagellar motility is considered an important virulence factor in different pathogenic bacteria. In the transcriptional repressor MogR regulates motility in a...
Flagellar motility is considered an important virulence factor in different pathogenic bacteria. In the transcriptional repressor MogR regulates motility in a temperature-dependent manner, directly repressing flagellar- and chemotaxis genes. The only other bacteria known to carry a homolog are members of the group, which includes motile species such as and as well as the non-motile species , and Furthermore, the main motility locus in group bacteria, carrying the genes for flagellar synthesis, appears to be more closely related to than to , which belongs to a separate phylogenetic group of Bacilli and does not carry a ortholog. Here, we show that in , MogR overexpression results in non-motile cells devoid of flagella. Global gene expression profiling showed that 110 genes were differentially regulated by MogR overexpression, including flagellar motility genes, but also genes associated with virulence, stress response and biofilm lifestyle. Accordingly, phenotypic assays showed that MogR also affects cytotoxicity and biofilm formation in . Overexpression of a MogR variant mutated in two amino acids within the putative DNA binding domain restored phenotypes to those of an empty vector control. In accordance, introduction of these mutations resulted in complete loss in MogR binding to its candidate flagellar locus target site . In contrast to , MogR appears to be regulated in a growth-phase dependent and temperature-independent manner in 407. Interestingly, was found to be conserved also in non-motile group species such as and , which both carry major gene deletions in the flagellar motility locus and where in is the only gene retained. Furthermore, is expressed in non-motile Altogether this provides indications of an expanded set of functions for MogR in group species, beyond motility regulation. In conclusion, MogR constitutes a novel pleiotropic transcriptional regulator, acting as a repressor of motility genes, and affecting the expression of a variety of additional genes involved in biofilm formation and virulence.
PubMed: 33424814
DOI: 10.3389/fmicb.2020.610650 -
Microbiology (Reading, England) Aug 1997Bacillus cereus, Bacillus thuringiensis and Bacillus mycoides are very closely related bacteria, generally considered as subspecies of B. cereus sensu lato. Different... (Comparative Study)
Comparative Study
Bacillus cereus, Bacillus thuringiensis and Bacillus mycoides are very closely related bacteria, generally considered as subspecies of B. cereus sensu lato. Different transposable elements have been isolated from B. thuringiensis, including IS231, IS232 and IS240 and their variants. The distribution of these three insertion sequences (IS) within the B. cereus group has been investigated in 90 strains of B. thuringiensis (representing 61 serovars), in 30 reference strains of B. cereus and in 33 strains of B. mycoides. Since these IS elements are delimited by well-conserved and specific inverted repeats, the use of primers corresponding to these ends allowed their amplification by PCR. The results showed that IS231 is the most abundant element in the three taxa, whereas IS232 is apparently exclusively associated with B. thuringiensis. Hybridization and Dral RFLP analysis of the PCR products confirmed and extended knowledge of the heterogeneity previously observed among iso-IS231 elements. Moreover, a similar diversity was observed among iso-IS240 elements. This contrasted with the relative homogeneity displayed by iso-IS232 elements. No specific association appeared to exist between any particular iso-element and a specific strain or serotype.
Topics: Bacillus; Bacillus cereus; Bacillus thuringiensis; Chromosomes, Bacterial; DNA Transposable Elements; Extrachromosomal Inheritance; Genetic Variation; Genome, Bacterial; Polymerase Chain Reaction; Reference Standards; Repetitive Sequences, Nucleic Acid; Serotyping; Species Specificity
PubMed: 9274007
DOI: 10.1099/00221287-143-8-2537 -
Molecular and Cellular Probes Dec 2009The Bacillus cereus group includes Bacillus anthracis, B. cereus, Bacillus thuringiensis, Bacillus mycoides and Bacillus weihenstephanensis. The small acid soluble spore...
The small acid soluble proteins (SASP alpha and SASP beta) of Bacillus weihenstephanensis and Bacillus mycoides group 2 are the most distinct among the Bacillus cereus group.
The Bacillus cereus group includes Bacillus anthracis, B. cereus, Bacillus thuringiensis, Bacillus mycoides and Bacillus weihenstephanensis. The small acid soluble spore protein (SASP) beta has been previously demonstrated to be among the biomarkers differentiating B. anthracis and B. cereus; SASP beta of B. cereus most commonly exhibits one or two amino acid substitutions when compared to B. anthracis. SASP alpha is conserved in sequence among these two species. Neither SASP alpha nor beta for B. thuringiensis, B. mycoides and B. weihenstephanensis have been previously characterized as taxonomic discriminators. In the current work molecular weight (MW) variation of these SASPs were determined by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for representative strains of the 5 species within the B. cereus group. The measured MWs also correlate with calculated MWs of translated amino acid sequences generated from whole genome sequencing projects. SASP alpha and beta demonstrated consistent MW among B. cereus, B. thuringiensis, and B. mycoides strains (group 1). However B. mycoides (group 2) and B. weihenstephanensis SASP alpha and beta were quite distinct making them unique among the B. cereus group. Limited sequence changes were observed in SASP alpha (at most 3 substitutions and 2 deletions) indicating it is a more conserved protein than SASP beta (up to 6 substitutions and a deletion). Another even more conserved SASP, SASP alpha-beta type, was described here for the first time.
Topics: Amino Acid Sequence; Bacillus; Bacillus anthracis; Bacillus cereus; Bacillus thuringiensis; Bacterial Proteins; Bacterial Typing Techniques; Molecular Sequence Data; Molecular Weight; Species Specificity; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 19616612
DOI: 10.1016/j.mcp.2009.07.003 -
Saudi Journal of Biological Sciences Jan 2019The Hout-Kasef is traditional salted fermented fish product of natural fermentation of salted mullet fish of coastal area of Jazan region of Saudi Arabia. The present...
The Hout-Kasef is traditional salted fermented fish product of natural fermentation of salted mullet fish of coastal area of Jazan region of Saudi Arabia. The present study was carried out to investigate the microbiological and chemical characteristic of Hout-Kasef. A total of twenty-four salted fish samples were purchased from fish market in Jazan and Abu-Arish at different times of the year. The microbial studies of salted-fermented fish revealed a total bacterial count ranging from 2.81 to 4.72 Log CFU/g, yeast and mold counts ranging from 0.48 to 3.14 Log CFU/g, total count 2.71-3.85 Log CFU/g, halophile bacteria count 3.26-5.14 Log CFU/g, and coliforms count <1 Log CFU/g. However, pathogenic bacteria such as Listeria spp spp. and species were not detected. The major bacteria species isolated and identified from the salted fermented fish were , , , , , , , , and The chemical analysis of salted fermented fish showed high content of moisture (47.96%), protein (25.71%), ash (19.6%) and salt (15.19%) but low contents of lipid (7.25%). The salted-fermented fish also showed high level of total volatile basic nitrogen (78.86 mg/100 gm sample) and thiobarbutric acid number (32.32 mg malonaldehyde/kg) with a pH value of pH 6.3. Finally, this study showed the presence of gram positive and gram negative bacteria in the fish product. The predominant microorganisms found were Bacillus and Staphylococcus spp. The fish product had high content of salt and TVB-N levels.
PubMed: 30622417
DOI: 10.1016/j.sjbs.2017.04.003 -
Applied and Environmental Microbiology May 1995A new solid medium has been developed for the enumeration and isolation of soil and rhizosphere microorganisms. This medium, named rhizosphere isolation medium, contains...
A new solid medium has been developed for the enumeration and isolation of soil and rhizosphere microorganisms. This medium, named rhizosphere isolation medium, contains glucose and 15 of the 20 common amino acids. The absence of five other amino acids, namely, aspartic acid, asparagine, cysteine, proline, and threonine, inhibits the growth of Bacillus mycoides, a commonly encountered bacterium that rapidly spreads on agar media and complicates the isolation and enumeration of other microorganisms. Compared with a similar medium containing Casamino Acids, rhizosphere isolation medium had half as many colonies of B. mycoides, with each colony approximately half the diameter. The two media had similar total numbers of bacterial colonies. Isolates were divided into taxononomic groups, roughly corresponding to species and genus, by fatty acid methyl ester analysis and numerical methods. There were 24 genera and 41 species found in the isolates from rhizosphere isolation medium, while 19 genera and 35 species were found in the isolates from the medium prepared with Casamino Acids. No major group of bacteria was found to occur only on one medium or on the other, indicating that the five missing amino acids had no great effect on organisms other than B. mycoides. This medium may prove useful in soil and rhizosphere studies in which the growth of B. mycoides is undesirable.
PubMed: 16535025
DOI: 10.1128/aem.61.5.1839-1842.1995 -
BMC Plant Biology May 2020Nitrogen is an essential element for sugarcane growth and development and is generally applied in the form of urea often much more than at recommended rates, causing...
BACKGROUND
Nitrogen is an essential element for sugarcane growth and development and is generally applied in the form of urea often much more than at recommended rates, causing serious soil degradation, particularly soil acidification, as well as groundwater and air pollution. In spite of the importance of nitrogen for plant growth, fewer reports are available to understand the application and biological role of N fixing bacteria to improve N nutrition in the sugarcane plant.
RESULTS
In this study, a total of 350 different bacterial strains were isolated from rhizospheric soil samples of the sugarcane plants. Out of these, 22 isolates were selected based on plant growth promotion traits, biocontrol, and nitrogenase activity. The presence and activity of the nifH gene and the ability of nitrogen-fixation proved that all 22 selected strains have the ability to fix nitrogen. These strains were used to perform 16S rRNA and rpoB genes for their identification. The resulted amplicons were sequenced and phylogenetic analysis was constructed. Among the screened strains for nitrogen fixation, CY5 (Bacillus megaterium) and CA1 (Bacillus mycoides) were the most prominent. These two strains were examined for functional diversity using Biolog phenotyping, which confirmed the consumption of diverse carbon and nitrogen sources and tolerance to low pH and osmotic stress. The inoculated bacterial strains colonized the sugarcane rhizosphere successfully and were mostly located in root and leaf. The expression of the nifH gene in both sugarcane varieties (GT11 and GXB9) inoculated with CY5 and CA1 was confirmed. The gene expression studies showed enhanced expression of genes of various enzymes such as catalase, phenylalanine-ammonia-lyase, superoxide dismutase, chitinase and glucanase in bacterial-inoculated sugarcane plants.
CONCLUSION
The results showed that a substantial number of Bacillus isolates have N-fixation and biocontrol property against two sugarcane pathogens Sporisorium scitamineum and Ceratocystis paradoxa. The increased activity of genes controlling free radical metabolism may at least in part accounts for the increased tolerance to pathogens. Nitrogen-fixation was confirmed in sugarcane inoculated with B. megaterium and B. mycoides strains using N-balance and N isotope dilution in different plant parts of sugarcane. This is the first report of Bacillus mycoides as a nitrogen-fixing rhizobacterium in sugarcane.
Topics: Host Microbial Interactions; Host-Pathogen Interactions; Microbiota; Nitrogen Fixation; Nitrogen-Fixing Bacteria; Rhizome; Saccharum
PubMed: 32423383
DOI: 10.1186/s12870-020-02400-9