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Topic Review
The Role of Outer Membrane Vesicles against Bacteria
Gram-negative bacteria are resistant to many commercialized antibiotics. The outer membrane (OM) of Gram-negative bacteria prevents the entry of such antibiotics. Outer membrane vesicles (OMV) are naturally released from the OM of Gram-negative bacteria for a range of purposes, including competition with other bacteria. OMV may carry, as part of the membrane or lumen, molecules with antibacterial activity. Such OMV can be exposed to and can fuse with the cell surface of different bacterial species. 
  • 1.0K
  • 07 Feb 2023
Topic Review
Therapeutic Applications of Bacteriophages in the Gut Microbiota
Bacteriophages (phages) are nano-sized viruses characterized by their inherent ability to live off bacteria. They utilize diverse mechanisms to absorb and gain entry into the bacterial cell wall via the release of viral genetic material, which uses the replication mechanisms of the host bacteria to produce and release daughter progeny virions that attack the surrounding host cells. They possess specific characteristics, including specificity for particular or closely related bacterial species. They have many applications, including as potential alternatives to antibiotics against multi-resistant bacterial pathogens and as control agents in bacteria-contaminated environments. They are ubiquitously abundant in nature and have diverse biota, including in the gut. Gut microbiota describes the community and interactions of microorganisms within the intestine. As with bacteria, parasitic bacteriophages constantly interact with the host bacterial cells within the gut system and have obvious implications for human health.
  • 1.0K
  • 17 Oct 2023
Topic Review
Microbial Biofilms
Biofilms are complex communities of microorganisms that grow on surfaces and are embedded in a matrix of extracellular polymeric substances. These are prevalent in various natural and man-made environments, ranging from industrial settings to medical devices, where they can have both positive and negative impacts.
  • 1.0K
  • 02 Aug 2023
Topic Review
Gut Microbiota and NAFLD
The pathogenesis of NAFLD is complex and not fully understood, but there is increasing evidence that the gut microbiota is strongly implicated in the development of NAFLD.
  • 1.0K
  • 04 Aug 2021
Topic Review
Microbial in Total Petroleum Hydrocarbon Polluted Soils
Nowadays, soil contamination by total petroleum hydrocarbons is still one of the most widespread forms of contamination. Intervention technologies are consolidated; however, full-scale interventions turn out to be not sustainable. Sustainability is essential not only in terms of costs, but also in terms of restoration of the soil resilience. Bioremediation has the possibility to fill the gap of sustainability with proper knowledge. Bioremediation should be optimized by the exploitation of the recent “omic” approaches to the study of hydrocarburoclastic microbiomes. To reach the goal, an extensive and deep knowledge in the study of bacterial and fungal degradative pathways, their interactions within microbiomes and of microbiomes with the soil matrix has to be gained. 
  • 1.0K
  • 27 Apr 2022
Topic Review
Rhizobium Symbiosis and Regulation Networks
Rhizobia refer to a polyphyletic group of Gram-negative bacteria that induce nodule formation on roots, or occasionally stems, of leguminous plants, where they reduce N2 into ammonia. The rhizobium symbiosis involves biological processes including communication with plant host, migration to the rhizosphere, rhizoplane colonization, induction of nodule and infection thread, intracellular host infection, accommodation in the plant cell, morphological differentiation, lifestyle change and cell function specialization. This represents a typical complicated trait that needs not only key symbiosis genes but also a large number of core and lineage-specific functions. 
  • 1.0K
  • 16 Jun 2023
Topic Review
Diagnosing Staph Infections with VOC Biomarkers
Staphylococci are broadly adaptable and their ability to grow in unique environments has been widely established, but the most common and clinically relevant staphylococcal niche is the skin and mucous membranes of mammals and birds. S. aureus causes severe infections in mammalian tissues and organs, with high morbidities, mortalities, and treatment costs. S. epidermidis is an important human commensal but is also capable of deadly infections. The development of volatile organic compound (VOC) profiles for the detection and identification of pathogens is an area of intensive research, with significant efforts toward establishing breath tests for infections.
  • 1.0K
  • 13 Mar 2023
Topic Review
Seagrass Rhizosphere Sediment Bacteria
Seagrasses are an important part of the coral reef ecosystem, and their rhizosphere microbes are of great ecological importance. However, variations in diversity, composition, and potential functions of bacterial communities in the seagrass rhizosphere of coral reef ecosystems remain unclear. This study employed the high-throughput sequencing based on 16S rDNA gene sequences and functional annotation of prokaryotic taxa (FAPROTAX) analysis to investigate these variations based on seagrass species and sampling locations, respectively. Results demonstrated that the seagrass rhizosphere microbial community was mainly dominated by phylum Proteobacteria (33.47%), Bacteroidetes (23.33%), and Planctomycetes (12.47%), while functional groups were mainly composed of sulfate respiration (14.09%), respiration of sulfur compounds (14.24%), aerobic chemoheterotrophy (20.87%), and chemoheterotrophy (26.85%). Significant differences were evident in alpha diversity, taxonomical composition and putative functional groups based on seagrass species and sampling locations. Moreover, the core microbial community of all investigated samples was identified, accounting for 63.22% of all obtained sequences. Network analysis indicated that most microbes had a positive correlation (82.41%), and two module hubs (phylum Proteobacteria) were investigated. Furthermore, a significant positive correlation was found between the OTUs numbers obtained and the functional groups assigned for seagrass rhizosphere microbial communities (p < 0.01). Our result would facilitate future investigation of the function of seagrass rhizosphere microbes. 
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  • 27 Aug 2021
Topic Review
New Antimicrobial Oleanonic Acid Polyamine Conjugates
The series of 21 oleanolic acid derivatives containing di- and polyamine fragments at position C3 and C28 was synthesized and evaluated for their antimicrobial activities against both Gram-positive and Gram-negative bacterial. Almost all series presented good to moderate Minimum Inhibitory Concentrations (MIC) against Gram-positive S. aureus, S. faecalis and B. cereus bacteria, moreover compounds possess important antimicrobial activities against Gram-negative E. coli, P. aeruginosa, S. enterica, and EA289 bacteria with MICs ranging from 6.25 to 200 µg/mL. The SAR data showed that the nature of the polyamine fragment, as well as differences in the structure of oleanolic acid plays an important role in the potential activities of tested compounds. The testing of the ability to restore the antibiotic activity of doxycycline and erythromycin at a 2 µg/mL concentration in a synergistic assay showed that only Mannich base with spermine fragment 6 lead to a moderate improvement in terms of antimicrobial activities of the different selected combinations against both P. aeruginosa and E. coli. The study of the mechanism of action of the most important compound in this series (amide 2i derived from N-methyl-norspermidine) showed the effect of disruption of the outer bacterial membrane of P. aeruginosa PA01 cells. Computational ADMET profiling renders compound 2i as a suitable starting point for pharmacokinetic optimization.
  • 1.0K
  • 19 Jan 2022
Topic Review
Metal(loid) Bioremediation by Microbial Polymers
Environmental pollution arising from metal(loid)s is a result of industrialization, and has led to serious health issues. Conventional methods of metal(loid) removal often result in generation of secondary waste which is toxic to the environment. Bioremediation in combination with physicochemical techniques offer an excellent and effective means of removal. The use of secondary metabolites and extracellular polymers produced by microorganisms is an effective procedure employed in metal(loid) sequestration and reduction in toxicity of contaminated environments. These biopolymers have different chemical structures and have shown varied selectivity to different metal(loid)s. 
  • 1.0K
  • 09 Jan 2023
Topic Review
The Two-Component Systems of Helicobacter pylori
Numerous studies of Helicobacter pylori, a human pathogen responsible for various stomach diseases, have focused on elucidating the mechanisms that regulate gene transcription to attempt to understand the physiological changes of the bacterium during infection and adaptation to the environmental conditions it encounters. The number of regulatory proteins inferred from genome sequence analyses responsible for properly orchestrating gene expression appears limited to three sigma factors and 14 regulators, including four Two-Component Systems and two orphan Response Regulators.
  • 1.0K
  • 02 Dec 2022
Topic Review
Candida auris
Candida auris is a multidrug-resistant species associated with high morbidity and mortality in immunocompromised individuals worldwide.
  • 1.0K
  • 04 Aug 2021
Topic Review
Microbiome Populations in the Nose
Acute and chronic upper respiratory illnesses such as asthma, and allergic rhinitis (AR) have been linked to the presence of microorganisms in the nose. Microorganisms can exist in symbiotic or commensal relationships with the human body. However, in certain cases, opportunistic pathogens can take over, leading to altered states (dysbiosis) and causing disease. Thus, the microflora present in a host can be useful to reflect health status. The human body contains 10 trillion to 100 trillion microorganisms. Of these populations, certain pathogens have been identified to promote or undermine wellbeing. Therefore, knowledge of the microbiome is potentially helpful as a diagnostic tool for many diseases. Variations have been recognized in the types of microbes that inhabit various populations based on geography, diet, and lifestyle choices and various microbiota have been shown to modulate immune responses in allergic disease. Interestingly, the diseases affected by these changes are prevalent in certain racial or ethnic populations. These prevalent microbiome variations in these groups suggest that the presence of these microorganisms may be significantly associated with health disparities. 
  • 1.0K
  • 24 Nov 2021
Topic Review
Syndecan-4
Emerging SARS-CoV-2 variants pose threats to vaccination campaigns against COVID-19. Being more transmissible than the original virus, the SARS-CoV-2 B.1.617 lineage, named the Delta variant, swept through the world in 2021. The mutations in the Delta’s spike protein shift the protein towards a net positive electrostatic potential. Compared to the wild-type spike, the Delta one shows a higher affinity towards heparan sulfate proteoglycans than ACE2. Cellular studies showed that syndecan-4, the syndecan isoform abundant in the lung, enhances the transmission of the Delta variant by attaching its mutated spike glycoprotein and facilitating its cellular entry. In addition to the attachment to the polyanionic heparan sulfate chains, the Delta spike’s molecular interactions with syndecan-4 also involve syndecan-4’s cell-binding domain that mediates cell-to-cell adhesion. Exogenously added heparin or syndecan-4 knockdown efficiently blocks the Delta variant’s cellular entry. A profound understanding of syndecan-4-mediated endocytosis enables the development of molecularly targeted yet simple strategies to reduce the Delta variant’s spread.
  • 1.0K
  • 20 Jan 2022
Topic Review
Sphinganine-Analog Mycotoxins
Sphinganine-analog mycotoxins (SAMs) including fumonisins and Alternaria alternata f. sp. Lycopersici (AAL) toxins are a group of related mycotoxins produced by plant pathogenic fungi in the Fusarium genus and in A. alternata f. sp. Lycopersici, respectively. SAMs have shown diverse cytotoxicity and phytotoxicity, causing adverse impacts on plants, animals, and humans, and are a destructive force to crop production worldwide.
  • 1.0K
  • 14 Jan 2021
Topic Review
Antigenicity of the Brucella Cell Wall
The members of Brucella spp. as Gram-negative bacteria are characterized by their sandwich-structured cell envelopes composed of the lipopolysaccharide (LPS)-covered bacterial outer membrane and the inner cytoplasmic cell membrane with a thin peptidoglycan layer between them in the periplasmic space.
  • 1.0K
  • 23 May 2023
Topic Review
Bacterial Metabolites Correlating with Depression
This comprehensive entry examines the different bacterial metabolites that potentially have implications for mental health issues such as depression.
  • 1.0K
  • 06 Jan 2021
Topic Review
Epidemiology of Human Salmonellosis
Salmonella is one of the most common zoonotic foodborne pathogens and a worldwide public health threat. Salmonella enterica is the most pathogenic among Salmonella species, comprising over 2500 serovars. It causes typhoid fever and gastroenteritis, and the serovars responsible for the later disease are known as non-typhoidal Salmonella (NTS). Among Salmonella infections, NTS infections are the most common cause of self-limiting illness. Enteric fever caused by typhoid Salmonella has a high mortality and morbidity rate and occurs more frequently in developing nations.
  • 1.0K
  • 06 May 2023
Topic Review
Clostridioides Difficile (Bacteria)
Clostridioides difficile (syn. Clostridium difficile), also known as C. difficile, or C. diff (/siː dɪf/), is Gram-positive species of spore-forming bacteria. Clostridioides spp. are anaerobic, motile bacteria, ubiquitous in nature and especially prevalent in soil. Its vegetative cells are rod-shaped, pleomorphic, and occur in pairs or short chains. Under the microscope, they appear as long, irregular (often drumstick- or spindle-shaped) cells with a bulge at their terminal ends (forms subterminal spores). Under Gram staining, C. difficile cells are Gram-positive and show optimum growth on blood agar at human body temperatures in the absence of oxygen. C. difficile is catalase- and superoxide dismutase-negative, and produces up to three types of toxins: enterotoxin A, cytotoxin B and Cytolethal distending toxin. Under stress conditions, the bacteria produce spores that are able to tolerate extreme conditions that the active bacteria cannot tolerate. Clostridioides difficile is an important emerging human pathogen; according to the CDC, in 2017 there were 223,900 cases in hospitalized patients and 12,800 deaths in the United States. Although C. difficile is commonly known as a hospital and antibiotic associated pathogen, at most one third of infections can be traced to transmission from an infected person in hospitals, and only a small number of antibiotics are directly associated with an elevated risk of developing a C. difficile infection (CDI), namely clindamycin, fluoroquinolones and cephalosporins. The majority of infections are acquired outside of hospitals, and most antibiotics have similar elevated risk of infection on par with many non-antibiotic risk factors, such as using stool softeners and receiving an enema. Clostridioides difficile can also become established in the human colon without causing disease. Although early estimates indicated that C. difficile was present in 2–5% of the adult population, more recent research indicates colonization is closely associated with a history of unrelated diarrheal illnesses, such as food poisoning or laxative abuse. Individuals with no history of gastrointestinal disturbances appear unlikely to become asymptomatic carriers. These carriers are thought to be a major reservoir of infection.
  • 1.0K
  • 24 Oct 2022
Topic Review
Cyclosporiasis Clinical Diagnosis
Cyclospora cayetanensis is an intestinal coccidian parasite transmitted to humans through the consumption of oocysts in fecally contaminated food and water. Infection is found worldwide and is highly endemic in tropical and subtropical regions with poor sanitation. Disease in developed countries is usually observed in travelers and in seasonal outbreaks associated with imported produce from endemic areas. Recently, summertime outbreaks in the United States have also been linked to locally grown produce. Cyclosporiasis causes a diarrheal illness which may be severe in infants, the elderly, and immunocompromised individuals. The increased adoption of highly sensitive molecular diagnostic tests, including commercially available multiplex panels for gastrointestinal pathogens, has facilitated the detection of infection and likely contributed to the increased reports of cases in developed countries. 
  • 1.0K
  • 22 Sep 2021
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