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Topic Review
Glacial Water
Microbial communities and nutrient dynamics in glaciers and ice sheets continuously change as the hydrological conditions within and on the ice change. Glaciers and ice sheets can be considered bioreactors as microbiomes transform nutrients that enter these icy systems and alter the meltwater chemistry. Global warming is increasing meltwater discharge, affecting nutrient and cell export, and altering proglacial systems.
  • 929
  • 15 May 2023
Topic Review
Severe Acute Respiratory Syndrome–Related Coronavirus
Severe acute respiratory syndrome–related coronavirus (SARSr-CoV or SARS-CoV)[note 1] is a species of virus consisting of many known strains phylogenetically related to severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) that have been shown to possess the capability to infect humans, bats, and certain other mammals. These enveloped, positive-sense single-stranded RNA viruses enter host cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. The SARSr-CoV species is a member of the genus Betacoronavirus and of the subgenus Sarbecovirus (SARS Betacoronavirus). Two strains of the virus have caused outbreaks of severe respiratory diseases in humans: severe acute respiratory syndrome coronavirus 1 (SARS-CoV or SARS-CoV-1), which caused the 2002–2004 outbreak of severe acute respiratory syndrome (SARS), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is causing the ongoing pandemic of COVID-19. There are hundreds of other strains of SARSr-CoV, which are only known to infect non-human species: bats are a major reservoir of many strains of SARSr-CoV; several strains have been identified in palm civets, which were likely ancestors of SARS-CoV-1. The SARS-related coronavirus was one of several viruses identified by the World Health Organization (WHO) in 2016 as a likely cause of a future epidemic in a new plan developed after the Ebola epidemic for urgent research and development before and during an epidemic towards diagnostic tests, vaccines and medicines. This prediction came to pass with the COVID-19 pandemic. Such development, if incorporating "nucleic acids coding for SARS-CoV virulence factors," which is listed on the Federal Select Agents and Toxins List, is expressly illegal in the United States per U.S. Federal Code 7 CFR Part 331, U.S. Federal Code 9 CFR Part 121, U.S. Federal Code 42 CFR Part 73, and 18 U.S. Code Section 178. The Statutes provide a legal remedy of 99 years in federal prison and up to $100,000,000 penalty per felony count. On March 3, 2022 a federal case was filed in the State of Utah seeking clarification of the legal status of Covid-19 gene therapies under these existing statutes, and the case is currently pending.
  • 927
  • 07 Nov 2022
Topic Review
Bacterial Polyhydroalkanoate in a Sustainable Future
Environmental challenges related to the mismanagement of plastic waste became even more evident during the COVID-19 pandemic. The need for new solutions regarding the use of plastics came to the forefront again. Polyhydroxyalkanoates (PHA) have demonstrated their ability to replace conventional plastics, especially in packaging. Its biodegradability and biocompatibility makes this material a sustainable solution. The cost of PHA production and some weak physical properties compared to synthetic polymers remain as the main barriers to its implementation in the industry. The scientific community has been trying to solve these disadvantages associated with PHA.
  • 927
  • 20 Feb 2023
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. 
  • 924
  • 16 Jun 2023
Topic Review
Plasmacytoid Dendritic Cell
Plasmacytoid dendritic cells (pDCs) are a rare type of immune cell that are known to secrete large quantities of type 1 interferon (IFNs) in response to a viral infection. They circulate in the blood and are found in peripheral lymphoid organs. They develop from bone marrow hematopoietic stem cells and constitute < 0.4% of peripheral blood mononuclear cells (PBMC). Other than conducting antiviral mechanisms, pDCs are considered to be key in linking the innate and adaptive immune systems. However, pDCs are also responsible for participating in and exacerbating certain autoimmune diseases like lupus. pDCs that undergo malignant transformation cause a rare hematologic disorder, blastic plasmacytoid dendritic cell neoplasm.
  • 923
  • 18 Nov 2022
Topic Review
Rhizosphere Microbial Communities and Heavy-Metals
The rhizosphere is a microhabitat where there is an intense chemical dialogue between plants and microorganisms. The two coexist and develop synergistic actions, which can promote plants’ functions and productivity, but also their capacity to respond to stress conditions, including heavy metal (HM) contamination.
  • 922
  • 28 Jul 2021
Topic Review
CRC and Gut Microbiota
The gut microbiota plays an important role in maintaining homeostasis in the human body, and the disruption of these communities can lead to compromised host health and the onset of disease.
  • 921
  • 23 Jun 2021
Topic Review
Antibiotic Bacterial Resistance
Antibiotics are the main treatment against bacterial infections in animals and plants. As explained before, efficacy loss is known as antibiotic resistance; this manifestation occurs when bacteria mutate in response to excess and sublethal doses of these drugs. Antibiotic resistance is usually classified into intrinsic and acquired resistance. The first one is constitutive of each species, which means that each generation will present it. In contrast, the acquired mechanism occurs when bacteria obtain resistance genes through conjugation, transformation, transduction, and transposition. Regardless of the type of resistance, both cause this problem.
  • 919
  • 18 Jan 2023
Topic Review
Juglans regia L. Pellicle Extract
The difficulty to treat resistant strains-related hospital-acquired infections (HAIs) promoted the study of phytoextracts, known sources of bioactive molecules. Accordingly, in the present study, the pharmacological activities of Juglans regia (L.) pellicle extract (WPE) were investigated. The antiviral effect was tested against Herpes simplex virus type 1 and 2, Poliovirus 1, Adenovirus 2, Echovirus 9, Coxsackievirus B1 through the plaque reduction assay. The antibacterial and antifungal activities were evaluated against medically important strains, by the microdilution method.
  • 918
  • 23 Jun 2021
Topic Review
Metals and Metalloids by Actinobacteria
Actinobacteria include high GC bacteria that inhabit a wide range of terrestrial and aquatic ecological niches, where they play essential roles in recycling or transforming organic and inorganic substances. The metal(loid) tolerance and/or resistance of several members of this phylum rely on mechanisms such as biosorption and extracellular sequestration by siderophores and extracellular polymeric substances (EPS), bioaccumulation, biotransformation, and metal efflux processes, which overall contribute to maintaining metal homeostasis.
  • 916
  • 08 Jan 2021
Topic Review
Microorganisms and Climate Change
Climate variations directly impacts on the primary productive sectors, such as agriculture, forestry, livestock, and commercial fishing, which present the subsequent economic relevance. As a result, the effect of climate change has been widely discussed for years on flora and fauna. However, the aftermath evaluation over the worldwide microbiota is a challenging task poorly considered, up to date. In fact, most of these effects have yet to be quantified, but the proliferation and geographycally spread of pathogens of plants, animals, or humans are providing clues of the possible results. These microbial issues should be kept in mind and are the core of this entry.
  • 916
  • 02 Jan 2024
Topic Review
Chaperone-Usher Fimbriae
Chaperone-usher fimbriae (CU) are linear, unbranching, outer-membrane pili secreted by Gram-negative bacteria through the chaperone-usher system rather than through type IV secretion or extracellular nucleation systems. These fimbriae are built up out of modular pilus subunits, which are transported into the periplasm in a Sec dependent manner. Chaperone-usher secreted fimbriae are important pathogenicity factors facilitating host colonisation, localisation and biofilm formation in clinically important species such as UPEC (uropathogenic Escherichia coli) and Pseudomonas aeruginosa.
  • 915
  • 15 Nov 2022
Topic Review
Epstein–Barr Virus in Periodontitis
Periodontitis, an inflammatory condition that affects the structures surrounding the tooth eventually leading to tooth loss, is one of the two biggest threats to oral health.
  • 914
  • 21 Jan 2021
Topic Review
Bacterial Amelioration of Plant Drought and Salt Stress
Soil bacteria can express different plant-beneficial activities, inoculation of plants with one or more non-antagonistic microorganisms, belonging to the same or different species, or including both prokaryotic and eukaryotic organisms, can often facilitate plant growth. In fact, the lack of one plant beneficial activity in one strain can sometimes be overcome if another microorganism expresses this specific physiological trait. Moreover, the combination of diverse plant growth-promoting microorganisms (PGPM) offers a wide range of positive activity to a plant, including the enhancement of plant growth, reduced susceptibility to soil-borne diseases, increased yield, and improved seed and fruit nutritional value.
  • 914
  • 17 Mar 2022
Topic Review
Variants of SARS-CoV-2
The immune response elicited by the current COVID-19 vaccinations declines with time, especially among the immunocompromised population. Furthermore, the emergence of novel SARS-CoV-2 variants, particularly the Omicron variant, has raised serious concerns about the efficacy of currently available vaccines in protecting the most vulnerable people.
  • 914
  • 19 Apr 2023
Topic Review
Sources of Bioavailable Water in Desert Ecosystems
Water availability is the dominant driver of microbial community structure and function in desert soils. However, these habitats typically only receive very infrequent large-scale water inputs (e.g., from precipitation and/or run-off). In light of studies, the paradigm that desert soil microorganisms are largely dormant under xeric conditions is questionable. Gene expression profiling of microbial communities in desert soils suggests that many microbial taxa retain some metabolic functionality, even under severely xeric conditions.
  • 912
  • 24 Jul 2023
Topic Review
Host Immune Response to Scedosporium/Lomentospora
Scedosporium/Lomentospora cell wall components, including peptidorhamnomannans (PRMs), α-glucans and glucosylceramides, are important immune response activators following their recognition by TLR2, TLR4 and Dectin-1 and through receptors that are yet unknown. After recognition, cytokine synthesis and antifungal activity of different phagocytes and epithelial cells is species-specific, highlighting the poor response by microglial cells against L. prolificans. Moreover, a great number of Scedosporium/Lomentospora antigens have been identified, most notably catalase, PRM and Hsp70 for their potential medical applicability. Against host immune response, these fungi contain evasion mechanisms, inducing host non-protective response, masking fungal molecular patterns, destructing host defense proteins and decreasing oxidative killing.
  • 910
  • 06 Mar 2021
Topic Review
The Role of Metallophores in Staphylococcus aureus
Staphylococcus aureus (S. aureus) is considered one of the most widespread infectious bacteria. It is found in the environment as well as being part of the human skin and nasal microbiota. Normally, S. aureus is harmless on healthy skin, but once it enters the blood or internal tissues, diverse infections occur including pneumonia, infection of surgical site and nosocomial bacteremia. Systemic S. aureus infection depends on the bacteria breaking through the epithelial protective layer. The incidence rate of this serious medical condition is between 20 and 50 cases/100,000 per year, with fatality rate ranging from 10% to 30%. Moreover, S. aureus forms biofilms that are associated with medical device infections such as prosthetic joints and endocarditis. The prevalence of antibiotic resistance S. aureus isolates, methicillin-resistant S. aureus (MRSA), is posing a serious problem for combating infectious diseases caused by this pathogen.
  • 910
  • 28 Oct 2022
Topic Review
Pseudomonas aeruginosa Metallophores
The human pathogen Pseudomonas aeruginosa (P. aeruginosa) causes several infections, both acute and chronic, mainly in hosts with compromised immunity and in patients suffering from cystic fibrosis. The pathogenesis of this bacterium is caused by several factors.
  • 910
  • 30 Nov 2022
Topic Review
Signaling Molecules in Endophytic Bacteria and Medicinal Plants
Signaling molecules act as the links and bridges between endophytes and host plants. The recognition of endophytes and host plants, the regulation of host plant growth and development, and the synthesis of secondary metabolites are not separated by the participation of signaling molecules.
  • 908
  • 20 Mar 2023
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