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Topic Review
Methicillin-Resistant Staphylococcus aureus Biofilms
The treatment of biofilm infection is difficult in clinical practice. Therefore, the eradication mechanisms of action of silver sulfadiazine, which is a well-utilized antibacterial compound, in a biofilm were investigated. Its unique mode of action in biofilms is defined. Biofilm-forming drug-resistant microbes are frequently detected in hospitals. Therefore, we examined the effects of silver sulfadiazine (SSD), a well-utilized antibacterial compound, and clarified the mechanisms underlying its activity against biofilms formed by methicillin-resistant Staphylococcus aureus (MRSA). The effects of SSD were a result of silver ions rather than sulfadiazine. SSD had a lesser revelation capacity of silver ions than silver nitrate; however, only SSD could eradicate mature biofilms by bacterial killing. Nevertheless, the effect was reduced by the addition of an ion chelator. Thus, the silver in SSD could be liberated after binding sulfadiazine to biofilms, and the use of SSD is reasonable in the eradication of biofilms in wounds.
  • 1.6K
  • 21 Oct 2020
Topic Review
Microbiota–Gut–Brain Axis in Mood Disorders
The microbiota–gut–brain axis is a bidirectional communication pathway that enables the gut microbiota to communicate with the brain through direct and indirect signaling pathways to influence brain physiology, function, and even behavior. Several taxonomic changes in the gut microbiota have been reported in neurodevelopmental disorders, mood disorders such as anxiety and depression, and neurodegenerative disorders such as Alzheimer’s disease. 
  • 1.6K
  • 17 Feb 2022
Topic Review
YdfD
ydfD is a lytic gene from the Qin cryptic prophage that encodes a 63-amino-acid protein, the ectopic expression of which in Escherichia coli can cause nearly complete cell lysis rapidly. The bacterial 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway is responsible for synthesizing the isoprenoids uniquely required for sustaining bacterial growth.
  • 1.6K
  • 21 Mar 2022
Topic Review
Plasmids Mediating Quinolone Resistance
Plasmid-mediated quinolone resistance (PMQR) remains one of the main mechanisms of bacterial quinolone resistance and plays an important role in the transmission of antibiotic resistance genes (ARGs). The two novel plasmids, p3M-2A and p3M-2B, which mediate quinolone resistance in Proteus vulgaris strain 3M (P3M) were identified. Of these, only p3M-2B appeared to be a qnrD-carrying plasmid. Both p3M-2A and p3M-2B could be transferred into Escherichia coli, and the latter caused a twofold change in ciprofloxacin resistance, according to the measured minimum inhibitory concentration (MIC). Plasmid curing/complementation and qRT-PCR results showed that p3M-2A can directly regulate the expression of qnrD in p3M-2B under treatment with ciprofloxacin, in which process, ORF1 was found to play an important role. Sequence alignments and phylogenetic analysis revealed the evolutionary relationships of all reported qnrD-carrying plasmids and showed that ORF1–4 in p3M-2B is the most conserved backbone for the normal function of qnrD-carrying plasmids. The identified direct repeats (DR) suggested that, from an evolutionary perspective, p3M-2B may have originated from the 2683-bp qnrD-carrying plasmid and may increase the possibility of plasmid recombination and then of qnrD transfer. To the best of our knowledge, this is the first identification of a novel qnrD-carrying plasmid isolated from a P. vulgaris strain of shrimp origin and a plasmid that plays a regulatory role in qnrD expression. This study also sheds new light on plasmid evolution and on the mechanism of horizontal transfer of ARGs encoded by plasmids.
  • 1.6K
  • 27 Oct 2020
Topic Review
Enteric Nervous System
The gastrointestinal tract has the function of digesting food, absorbing the nutrients, and forming a barrier against harmful agents, but it is also an immune-hormonal system. Functional aspects of this system, such as peristaltic movements, substance transport, and local blood flow, are regulated by an intrinsic network of neuronal ganglia known as the enteric nervous system (ENS). The ENS provides motor excitatory neurons, innervate muscle layers, secretory glands, and the lymphatic vascular system. It is the largest and most complex part of the peripheral nervous system, being organized into distinct neuron networks within the gut wall, where individual small ganglia are interconnected by dense fiber bundles. These nerve plexuses are organized into two layers of neuronal ganglia and enteroglial cells that are interconnected: The myenteric plexus (Auerbach plexus) and the submucosa plexus (Meissner plexus). The ENS forms a complete sensory-motor reflex composed of intrinsic primary afferent neurons (IPANs), interneurons, and motor neurons.
  • 1.6K
  • 14 Jan 2021
Topic Review
Targeting Gut Microbial Biofilms
Colorectal cancer (CRC) is a global public health issue which poses a substantial humanistic and economic burden on patients, healthcare systems and society. In recent years, intestinal dysbiosis has been suggested to be involved in the pathogenesis of CRC, with specific pathogens exhibiting oncogenic potentials such as Fusobacterium nucleatum, Escherichia coli and enterotoxigenic Bacteroides fragilis having been found to contribute to CRC development. More recently, it has been shown that initiation of CRC development by these microorganisms requires the formation of biofilms. Gut microbial biofilm forms in the inner colonic mucus layer and is composed of polymicrobial communities. Biofilm results in the redistribution of colonic epithelial cell E-cadherin, increases permeability of the gut and causes a loss of function of the intestinal barrier, all of which enhance intestinal dysbiosis. This literature review aims to compile the various strategies that target these pathogenic biofilms and could potentially play a role in the prevention of CRC. We explore the potential use of natural products, silver nanoparticles, upconverting nanoparticles, thiosalicylate complexes, anti-rheumatic agent (Auranofin), probiotics and quorum-sensing inhibitors as strategies to hinder colon carcinogenesis via targeting colon-associated biofilms.
  • 1.6K
  • 22 Oct 2020
Topic Review
Elite Rhizobia Strains in Africa
Grain legumes play a significant role in smallholder farming systems in Africa because of their contribution to nutrition and income security and their role in fixing nitrogen. Biological Nitrogen Fixation (BNF) serves a critical role in improving soil fertility for legumes. Dinitrogen can be reduced to ammonium (NH3) through the Haber–Bosch process or via biological nitrogen fixation (BNF) utilizing some soil bacteria or archaea (diazotrophs). Rhizobia belong to Alphaproteobacteria and Betaproteobacteria, a group of Gram-negative bacteria that forms nodules on roots (sometimes stems) of leguminous plants to fix nitrogen in a symbiotic relationship with their host plants. The rhizobia–legume symbiosis is the most studied plant–microbial mutualism because of the importance of nitrogen fixation for almost all agricultural systems.
  • 1.6K
  • 21 Jul 2022
Topic Review
Bacterial Mechanosensitive Channels
Bacteria accumulate osmolytes to prevent cell dehydration during hyperosmotic stress. A sudden change to a hypotonic environment leads to a rapid water influx, causing swelling of the protoplast. To prevent cell lysis through osmotic bursting, mechanosensitive channels detect changes in turgor pressure and act as emergency-release valves for the ions and osmolytes, restoring the osmotic balance.
  • 1.6K
  • 11 Jul 2022
Topic Review Peer Reviewed
Morphometric Characterization of Bacteria Associated with Bacteremia
Among the leading causes of bacteremia are Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. E. coli and K. pneumoniae are increasingly exhibiting resistance to last-resort antibiotics, such as carbapenems. Rapid and accurate identification of these pathogens is critical for timely treatment and infection control. This paper aimed to develop a computer-aided bacterial morphometric technique for identifying and classifying wild-type E. coli, K. pneumoniae, and S. aureus in a field guide fashion. A 3D laser scanning confocal microscope was used to gather key parameters of each organism: length (L, µm), circular diameter (CD, µm), volume (V, µm3), surface area-to-cross-sectional area ratio (SA/CSA, unitless), surface uniformity ratio (Str), and surface texture ratio (Sdr). Microscope images and measurement results showed that S. aureus was spherical with the shortest length (1.08 µm) and smallest volume (0.52 µm3). E. coli and K. pneumoniae were rod-shaped with lengths >2.0 µm and volumes >1.0 µm3. Carbapenem-resistant (CR) strains exhibited larger volumes than their wild-type counterparts. Surface parameters further differentiated strains: wild-type E. coli had a greater surface texture or a less smooth surface (larger Sdr) than K. pneumoniae (lower Sdr) did. CR E. coli had more surface uniformity (lower Str) than CR K. pneumoniae did. A dichotomous key based on shape, circular diameter, volume, length, and surface characteristics was developed to classify the species using a series of paired, contrasting features. This morphometric analysis can aid researchers in quickly identifying bacteria, leading to faster diagnosis of life-threatening diseases and improved treatment decisions.
  • 1.6K
  • 28 Aug 2025
Topic Review
Occurrence of Triclosan in the Water Environment
Triclosan (TCS), a kind of pharmaceuticals and personal care products (PPCPs), is widely used and has had a large production over years. It is an emerging pollutant in the water environment that has attracted global attention due to its toxic effects on organisms and aquatic ecosystems, and its concentrations in the water environment are expected to increase since the COVID-19 pandemic outbreak.
  • 1.6K
  • 09 Sep 2022
Topic Review
ESKAPE Bacteria in the Dog
ESKAPE bacteria (i.e., Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are a group of common opportunistic pathogens associated mainly with nosocomial infections.
  • 1.6K
  • 30 Oct 2020
Topic Review
RBUD
RBUD, read-based metagenomics profiling for unestablished database, is a new functional potential analysis approach for whole microbial genome shotgun sequencing. Based on whole metagenome shotgun sequencing data, it can be used to analysis microbial species and functions, especially for the study without relevant reference database. RBUD method is optimized by omitting the steps of contigs assembly and ORF prediction which improves the utilization of sequencing data and shortens the time of data analysis. In addition, RBUD method includes the steps of establishing databases of microorganisms from different sources to expand its application, which is a great help for small-sample research and can avoid the lack of reference database. By compared RBUD with the existing methods in practical applications, RBUD has great advantages in both species and functional analysis.
  • 1.6K
  • 21 Oct 2020
Topic Review
Respiratory System and its Microbiome
Several studies suggest the importance of preserving the micro-ecosystem of commensal, symbiotic and pathogenic microbes of the respiratory system, and, more recently, its relationship with the intestinal microbiome. However, recent studies investigate how it leads to the maintenance of human health, also in relation to some factors such as the effect of age, diet and others, making its composition and stability better understood.  
  • 1.6K
  • 09 Nov 2020
Topic Review
Biotechnological Importance of Torulaspora delbrueckii
Torulaspora delbrueckii has attracted interest in recent years, especially due to its biotechnological potential, arising from its flavor- and aroma-enhancing properties when used in wine, beer or bread dough fermentation, as well as from its remarkable resistance to osmotic and freezing stresses.    
  • 1.6K
  • 23 Sep 2021
Topic Review
Antimicrobial Resistance Assessment in Aquacultures
Aquaculture is a new food production sector that has been increasing dramatically over the last two decades due to the high demand for a healthy protein source. The aquaculture production figures indicate a substantial increase in the relative contribution of aquaculture to total fish consumption from 5% in 1962 to 49% in 2002. The use of antimicrobials in aquaculture, even at subinhibitory concentrations, has been promoting antimicrobial resistance in bacteria from the aquatic environment. New omics tools and approaches pave the way for the assessment of antimicrobial resistance in these environments.
  • 1.6K
  • 19 Jul 2021
Topic Review
Streptobacillus Moniliformis
Streptobacillus moniliformis is a non-motile, Gram-negative rod-shaped bacterium that is a member of the family Leptotrichiaceae. The genome of S. moniliformis is one of two completed sequences of the order Fusobacteriales. Its name comes from the Greek word streptos for "curved" or "twisted", and the Latin words bacillus meaning "small rod" and moniliformis for "necklace". S. moniliformis is microaerophilic, requiring less oxygen than is present in the atmosphere for its growth.
  • 1.6K
  • 03 Nov 2022
Topic Review
Bartonella henselae in a Biofilm
Bartonella henselae (B. henselae) is a gram-negative bacterium that causes cat scratch disease, bacteremia, and endocarditis, as well as other clinical presentations. B. henselae has been shown to form a biofilm in vitro that likely plays a role in the establishment and persistence of the bacterium in the host.
  • 1.6K
  • 28 Apr 2021
Topic Review
Varidnaviria
Varidnaviria is a realm of viruses that includes all DNA viruses that encode major capsid proteins that contain a vertical jelly roll fold. The major capsid proteins (MCP) form into pseudohexameric subunits of the viral capsid, which stores the viral deoxyribonucleic acid (DNA), and are perpendicular, or vertical, to the surface of the capsid. Apart from this, viruses in the realm also share many other characteristics, such as minor capsid proteins (mCP) with the vertical jelly roll fold, an ATPase that packages viral DNA into the capsid, and a DNA polymerase that replicates the viral genome. Varidnaviria was established in 2019 based on the shared characteristics of the viruses in the realm. There are two groups of viruses in Varidnaviria: viruses that have a double vertical jelly roll (DJR) folds in the MCP, assigned to the kingdom Bamfordvirae, and viruses that have a single vertical jelly roll (SJR) fold in the MCP, assigned to the kingdom Helvetiavirae. The DJR-MCP lineage is thought to be descended from the SJR-MCP lineage via a gene fusion event, and the SJR-MCP shows a close relation to nucleoplasmins, pointing to a possible origin of the realm's jelly roll fold MCP. Most identified eukaryotic DNA viruses belong to Varidnaviria. Marine viruses in the realm are highly abundant worldwide and are important in marine ecology. Many animal viruses in the realm are associated with disease, including adenoviruses, poxviruses, and the African swine fever virus. Poxviruses have been prominent in the history of medicine, especially smallpox, caused by Variola virus, which was the target of the first vaccine and which later became the first disease eradicated. The realm also notably includes giant viruses that are physically larger and contain a much larger number of genes than typical viruses.
  • 1.6K
  • 20 Oct 2022
Topic Review
Wood Antimicrobial Behavior Test Method
Some wood species have antimicrobial properties and a variety of methods are used to investigate them. For testing the effect of antimicrobial compounds, direct and indirect methods are used. Meanwhile, the survival of microbes is also tested on surfaces (or material in contact with microbes) to validate the safety of surfaces.
  • 1.6K
  • 29 Oct 2020
Topic Review
Microalgae Encapsulation
Microalgae are microorganisms with a singular biochemical composition, including several biologically active compounds with proven pharmacological activities, such as anticancer, antioxidant and anti-inflammatory activities, among others. These properties make microalgae an interesting natural resource to be used as a functional ingredient, as well as in the prevention and treatment of diseases, or cosmetic formulations. Nevertheless, natural bioactives often possess inherent chemical instability and/or poor solubility, which are usually associated with low bioavailability. As such, their industrial potential as a health-promoting substance might be severely compromised. In this context, encapsulation systems are considered as a promising and emerging strategy to overcome these shortcomings due to the presence of a surrounding protective layer.
  • 1.6K
  • 23 Apr 2021
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