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World Journal of Microbiology &... Aug 2022With the advent of green chemistry, the use of enzymes in industrial processes serves as an alternative to the conventional chemical catalysts. A high demand for... (Review)
Review
With the advent of green chemistry, the use of enzymes in industrial processes serves as an alternative to the conventional chemical catalysts. A high demand for sustainable processes for catalysis has brought a significant attention to hunt for novel enzymes. Among various hydrolases, the α-amylase has a gamut of biotechnological applications owing to its pivotal role in starch-hydrolysis. Industrial demand requires enzymes with thermostability and to ameliorate this crucial property, various methods such as protein engineering, directed evolution and enzyme immobilisation strategies are devised. Besides the traditional culture-dependent approach, metagenome from uncultured bacteria serves as a bountiful resource for novel genes/biocatalysts. Exploring the extreme-niches metagenome, advancements in protein engineering and biotechnology tools encourage the mining of novel α-amylase and its stable variants to tap its robust biotechnological and industrial potential. This review outlines α-amylase and its genetics, its catalytic domain architecture and mechanism of action, and various molecular methods to ameliorate its production. It aims to impart understanding on mechanisms involved in thermostability of α-amylase, cover strategies to screen novel genes from futile habitats and some molecular methods to ameliorate its properties.
Topics: Enzymes, Immobilized; Metagenome; Protein Engineering; Starch; alpha-Amylases
PubMed: 35999473
DOI: 10.1007/s11274-022-03396-0 -
Alimentary Pharmacology & Therapeutics Nov 2015The human intestinal microbiota is a key regulator of host metabolic and immune functions and alterations in the microbiome ('dysbiosis') have been implicated in several... (Review)
Review
BACKGROUND
The human intestinal microbiota is a key regulator of host metabolic and immune functions and alterations in the microbiome ('dysbiosis') have been implicated in several human diseases. Because of the anatomical links between the intestines and the liver, dysbiosis may also disrupt hepatic function and thereby contribute to the pathogenesis of nonalcoholic fatty liver disease (NAFLD).
AIM
To perform a comprehensive review of the medical literature investigating associations between intestinal dysbiosis and NAFLD, with a particular emphasis on studies that characterise the microbiome in NAFLD.
METHODS
We conducted a search of PubMed, Embase, and Web of Science using multiple search terms including: 'NAFLD, NASH, fatty liver, steatohepatitis' combined with 'metagenome, microbiom*, microbiota*, fecal flora, intestinal flora, gut bacteria'. Results were manually reviewed and studies selected based on relevance to intestinal microbiota and NAFLD. We also included studies that addressed potential mechanistic models of pathways linking the dysbiosis to NAFLD.
RESULTS
Nine studies (five human and four animal models) were identified in our search that assessed associations between specific intestinal microbiota composition and NAFLD. We reviewed and summarised the results of additional investigations that more broadly addressed the mechanisms by which the microbiome may impact NAFLD pathogenesis.
CONCLUSIONS
Investigations in humans and animals demonstrate associations between intestinal dysbiosis and NAFLD; however, causality has not been proven and mechanistic links require further delineation. As the field of microbiome research matures in techniques and study design, more detailed insights into NAFLD pathogenesis and its associations with the intestinal microbiota will be elucidated.
Topics: Animals; Dysbiosis; Humans; Intestines; Metagenome; Microbiota; Models, Animal; Non-alcoholic Fatty Liver Disease
PubMed: 26304302
DOI: 10.1111/apt.13376 -
Antonie Van Leeuwenhoek Jul 2014In the 80 years that have passed since the first issue of Antonie van Leeuwenhoek was published, the field of prokaryote systematics has changed dramatically. The 4th... (Review)
Review
In the 80 years that have passed since the first issue of Antonie van Leeuwenhoek was published, the field of prokaryote systematics has changed dramatically. The 4th edition of Bergey's Manual of Determinative Bacteriology (1934) described 132 genera and 2,703 species. The numbers of genera and species with names with standing in the nomenclature in August 2013 were 2,390 and 11,482, respectively, including no more than 75 genera and 250 species that were recognized in 1934. In the years 2006-2012, on average 624 new species were added annually, most of which were described by scientists in Asian countries. We review the past and current species concept for the prokaryotes and the current requirements for the description of new species, based on a 'polyphasic' approach. We discuss the impact of genomics and metagenomics and other new trends toward revitalization of prokaryote systematics, and provide some ideas and speculations on possible future developments in the field.
Topics: Bacteria; History, 20th Century; History, 21st Century; Microbiology; Prokaryotic Cells; Systems Biology
PubMed: 24306768
DOI: 10.1007/s10482-013-0084-1 -
Experimental Dermatology Oct 2021Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory skin disease with still largely unknown pathogenesis. While infectious organisms...
Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory skin disease with still largely unknown pathogenesis. While infectious organisms have been identified in lesions of the disease since the 1980s, questions remain over the role that bacteria and microbiome play. Recent studies using 16S ribosomal RNA gene sequencing and larger culture-based studies have begun to paint a clearer picture of the microbial world of HS. With this systematic review, we summarize all the work that has been done to date in HS bacteriology, analyse potential pitfalls and limitations of the current studies, and address future directions of investigation. This systematic review attempted to collate and analyse all bacteriology studies done to date. This review was prospectively registered with PROSPERO (1670769) performed in line with the PRISMA checklist. Twenty two studies were identified comprising 862 individual HS patients for culture studies and 206 HS patients for 16S rRNA gene sequencing studies. Methodology tended to be varied, with different sampling, culturing and sequencing methods as well as amount of analysis and stratification of patients. Bacteria identified as elevated in HS lesions in sequencing studies as well as grown from HS lesions in culture studies are identified and discussed. These primarily included the anerobic Gram-negative bacilli Prevotella, Porphyromonas and Fusibacterium, the Gram-positive bacilli Corynebacterium, and the Gram-positive cocci Staphylococcus, Streptococcus and Parvimonas. Potential interactions, as well as work in other disease models with related bacteria are also discussed. Areas of further investigation include in vitro studies of interactions between bacteria and keratinocytes, gut and oral microbiome studies and deep sequencing studies for virulence and phage factors.
Topics: Hidradenitis Suppurativa; Humans; Metagenomics; Microbiota; Skin
PubMed: 32614993
DOI: 10.1111/exd.14141 -
Asia Pacific Allergy Jul 2022Individual studies have suggested that upper airway dysbiosis may be associated with asthma or its severity. We aimed to systematically review studies that evaluated... (Review)
Review
Individual studies have suggested that upper airway dysbiosis may be associated with asthma or its severity. We aimed to systematically review studies that evaluated upper airway bacterial microbiota in relation to asthma, compared to nonasthmatic controls. Searches used MEDLINE, Embase, and Web of Science Core Collection. Eligible studies included association between asthma and upper airway dysbiosis; assessment of composition and diversity of upper airway microbiota using 16S rRNA or metagenomic sequencing; upper airway samples from nose, nasopharynx, oropharynx or hypopharynx. Study quality was assessed and rated using the Newcastle-Ottawa scale. A total of 249 publications were identified; 17 in the final analysis (13 childhood asthma and 4 adult asthma). Microbiome richness was measured in 6 studies, species diversity in 12, and bacterial composition in 17. The quality of evidence was good and fair. The alpha-diversity was found to be higher in younger children with wheezing and asthma, while it was lower when asthmatic children had rhinitis or mite sensitization. In children, Proteobacteria and Firmicutes were higher in asthmatics compared to controls (7 studies), and , , and were predominant in the bacterial community. In pooled analysis, nasal colonization was associated with the presence of wheezing at age 5 ( = 0.04). In adult patients with asthma, the abundance of Proteobacteria was elevated in the upper respiratory tract (3 studies). Nasal colonization of was lower in asthmatics (2 studies). This study demonstrates the potential relationships between asthma and specific bacterial colonization in the upper airway in adult and children with asthma.
PubMed: 35966153
DOI: 10.5415/apallergy.2022.12.e32 -
Microorganisms Nov 2020Rosacea is a chronic inflammatory skin disorder of a not fully understood pathophysiology. Microbial factors, although not precisely characterized, are speculated to... (Review)
Review
Rosacea is a chronic inflammatory skin disorder of a not fully understood pathophysiology. Microbial factors, although not precisely characterized, are speculated to contribute to the development of the condition. The aim of the current review was to summarize the rosacea-associated alterations in the skin, blood, and gut microbiome, investigated using culture-independent, metagenomic techniques. A systematic review of the PubMed, Web of Science, and Scopus databases was performed, according to PRISMA (preferred reporting items for systematic review and meta-analyses) guidelines. Nine out of 185 papers were eligible for analysis. Skin microbiome was investigated in six studies, and in a total number of 115 rosacea patients. Blood microbiome was the subject of one piece of research, conducted in 10 patients with rosacea, and gut microbiome was studied in two papers, and in a total of 23 rosacea subjects. Although all of the studies showed significant alterations in the composition of the skin, blood, or gut microbiome in rosacea, the results were highly inconsistent, or even, in some cases, contradictory. Major limitations included the low number of participants, and different study populations (mainly Asians). Further studies are needed in order to reliably analyze the composition of microbiota in rosacea, and the potential application of microbiome modifications for the treatment of this dermatosis.
PubMed: 33171692
DOI: 10.3390/microorganisms8111756 -
Seminars in Liver Disease Nov 2017The authors conducted a meta-analysis of the prevalence of small intestinal bacterial overgrowth (SIBO) in patients with chronic liver disease (CLD) and controls. Using... (Meta-Analysis)
Meta-Analysis Review
The authors conducted a meta-analysis of the prevalence of small intestinal bacterial overgrowth (SIBO) in patients with chronic liver disease (CLD) and controls. Using the search terms "small intestinal bacterial overgrowth (SIBO)" and "chronic liver disease (CLD)" or "cirrhosis," 19 case-control studies were identified. Utilizing breath tests, the prevalence of SIBO in CLD was 35.80% (95% CI, 32.60-39.10) compared with 8.0% (95% CI, 5.70-11.00) in controls. Using culture techniques, the prevalence was 68.31% (95% CI, 59.62-76.00) in CLD patients as compared with 7.94% (95% CI, 3.44-12.73) in controls. No difference between cirrhotic and noncirrhotic patients was found. SIBO is significantly more frequent in CLD patients as compared with controls. The association of SIBO and CLD was not confined to patients with advanced CLD, suggesting that SIBO is not a consequence of advanced liver disease but may play a role in the progression of CLD.
Topics: Bacteria; Disease Progression; Dysbiosis; Gastrointestinal Microbiome; Host-Pathogen Interactions; Humans; Intestine, Small; Liver Diseases; Prevalence; Prognosis; Risk Factors
PubMed: 29272899
DOI: 10.1055/s-0037-1608832 -
The Japanese Dental Science Review Dec 2023The mechanisms modulated by periodontal pathogens in atherosclerosis are not fully understood. Aim: to perform an integrative analysis of gene and protein expression... (Review)
Review
UNLABELLED
The mechanisms modulated by periodontal pathogens in atherosclerosis are not fully understood. Aim: to perform an integrative analysis of gene and protein expression modulated by periodontal pathogens in cells and animal models for atherosclerosis.
METHODS
Cochrane, PRISMA and AMSTAR2 guidelines for systematic reviews were followed. Data search was conducted in Pub-med, LILACS and Science Direct databases. Gene and protein expression data were collected from the included papers to perform an overrepresentation analysis using the Reactome Pathway Analysis tool and the KEGG database.
RESULTS
Thirty-two papers were included in the review, they analyzed the effect of , , , , , and or/and their virulent factors on gene and protein expression in human cells and animal models of atherosclerosis. Some of the modulated pathways include the immune system, programmed cell death, cellular responses to external stimuli, transport of small molecules, and signal transduction (p < 0.05). Those pathways are known to be involved in different stages of atherosclerosis progression.
CONCLUSION
Based on the performed analysis, it is possible to state that periodontal pathogens have the potential to be a contributing factor for atherosclerosis even in absence of a high-fat diet or high shear stress.
PubMed: 36654677
DOI: 10.1016/j.jdsr.2022.12.001 -
Chemistry & Biodiversity Dec 2023Endophytic fungi are associated with plant health and represent a remarkable source of potential of enzymes and bioactive compounds, but the diversity of endophytes... (Review)
Review
Endophytic fungi are associated with plant health and represent a remarkable source of potential of enzymes and bioactive compounds, but the diversity of endophytes remains uncertain and poorly explored, especially in Cactaceae, one of the most species-rich families adapted to growing in arid and semi-arid regions. The aim of this study was to conduct a systematic review on the diversity and bioprospecting of endophytic fungi from Cactaceae. We analysed peer-reviewed articles from seven databases using PRISMA guidelines. The results showed that the Cactaceae family is a source of new taxa, but the diversity of endophytic fungi of Cactaceae is little explored, mainly the diversity among tissues and by metagenomics. Bioprospecting studies have shown that these microorganisms can be used in the production of enzymes and larvicidal and antifungal compounds. Our results are relevant as a starting point for researchers to develop studies that expand the knowledge of plant mycobiota in arid and semi-arid ecosystems, as well as comprising a remarkable source of fungal compounds with several biotechnological applications.
Topics: Humans; Bioprospecting; Fungi; Cactaceae; Ecosystem; Antifungal Agents; Endophytes; Plants
PubMed: 37934008
DOI: 10.1002/cbdv.202301413 -
Frontiers in Pediatrics 2023Pediatric and neonatal sepsis is one of the main causes of mortality and morbidity in these age groups. Accurate and early etiological identification is essential for... (Review)
Review
INTRODUCTION
Pediatric and neonatal sepsis is one of the main causes of mortality and morbidity in these age groups. Accurate and early etiological identification is essential for guiding antibiotic treatment, improving survival, and reducing complications and sequelae. Currently, the identification is based on culture-dependent methods, which has many limitations for its use in clinical practice, and obtaining its results is delayed. Next-generation sequencing enables rapid, accurate, and unbiased identification of multiple microorganisms in biological samples at the same time. The objective of this study was to characterize the etiology of neonatal and pediatric sepsis by metagenomic techniques.
METHODS
A systematic review of the literature was carried out using the PRISMA-2020 guide. Observational, descriptive, and case report studies on pediatric patients were included, with a diagnostic evaluation by clinical criteria of sepsis based on the systemic inflammatory response, in sterile and non-sterile biofluid samples. The risk of bias assessment of the observational studies was carried out with the STROBE-metagenomics instrument and the CARE checklist for case reports.
RESULTS AND DISCUSSION
Five studies with a total of 462 patients were included. Due to the data obtained from the studies, it was not possible to perform a quantitative synthesis (meta-analysis). Based on the data from the included studies, the result identified that mNGS improves the etiological identification in neonatal and pediatric sepsis, especially in the context of negative cultures and in the identification of unusual microorganisms (bacteria that are difficult to grow in culture, viruses, fungi, and parasites). The number of investigations is currently limited, and the studies are at high risk of bias. Further research using this technology would have the potential to improve the rational use of antibiotics.
PubMed: 37063664
DOI: 10.3389/fped.2023.1011723