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Topic Review
Diversity of Deep-Sea Actinobacteria and Natural Products
Bioprospecting of novel antibiotics has been the conventional norm of research fostered by researchers worldwide to combat drug resistance. With the exhaustion of incessant leads, the search for new chemical entities moves into uncharted territories such as the deep sea. The deep sea is a furthermost ecosystem with much untapped biodiversity thriving under extreme conditions. Accordingly, it also encompasses a vast pool of ancient natural products. Actinobacteria are frequently regarded as the bacteria of research interest due to their inherent antibiotic-producing capabilities. These interesting groups of bacteria occupy diverse ecological habitats including a multitude of different deep-sea habitats.
  • 968
  • 18 Jan 2023
Topic Review
Thin Layers (Oceanography)
Thin layers are concentrated aggregations of phytoplankton and zooplankton in coastal and offshore waters that are vertically compressed to thicknesses ranging from several centimeters up to a few meters and are horizontally extensive, sometimes for kilometers. Generally, thin layers have three basic criteria: 1) they must be horizontally and temporally persistent; 2) they must not exceed a critical threshold of vertical thickness; and 3) they must exceed a critical threshold of maximum concentration. The precise values for critical thresholds of thin layers has been debated for a long time due to the vast diversity of plankton, instrumentation, and environmental conditions. Thin layers have distinct biological, chemical, optical, and acoustical signatures which are difficult to measure with traditional sampling techniques such as nets and bottles. However, there has been a surge in studies of thin layers within the past two decades due to major advances in technology and instrumentation. Phytoplankton are often measured by optical instruments that can detect fluorescence such as LIDAR, and zooplankton are often measured by acoustic instruments that can detect acoustic backscattering such as ABS. These extraordinary concentrations of plankton have important implications for many aspects of marine ecology (e.g., phytoplankton growth dynamics, zooplankton grazing, behaviour, environmental effects, harmful algal blooms), as well as for ocean optics and acoustics. Zooplankton thin layers are often found slightly under phytoplankton layers because many feed on them. Thin layers occur in a wide variety of ocean environments, including estuaries, coastal shelves, fjords, bays, and the open ocean, and they are often associated with some form of vertical structure in the water column, such as pycnoclines, and in zones of reduced flow.
  • 944
  • 09 Nov 2022
Topic Review
Production of Bioactive Compounds and Bioethanol using Macroalgae
To achieve sustainable development, alternative resources should replace conventional resources such as fossil fuels. In marine ecosystems, many macroalgae grow faster than terrestrial plants. Macroalgae are roughly classified as green, red, or brown algae based on their photosynthetic pigments. Brown algae are considered to be a source of physiologically active substances such as polyphenols. Furthermore, some macroalgae can capture approximately 10 times more carbon dioxide from the atmosphere than terrestrial plants. Therefore, they have immense potential for use in the environment. Macroalgae have emerged as a biomass feedstock for bioethanol production owing to their low lignin content and applicability to biorefinery processes.
  • 937
  • 16 Jun 2023
Topic Review
List of Seaweeds of South Africa
This is a list of seaweeds recorded from the oceans bordering South Africa. This list comprises locally used common names, scientific names with author citation and recorded ranges. Ranges specified may not be the entire known range for the species, but should include the known range within the waters surrounding the Republic of South Africa. List ordering and taxonomy complies where possible with the current usage in Algaebase, and may differ from the cited source, as listed citations are primarily for range or existence of records for the region. Sub-taxa within any given taxon are arranged alphabetically as a general rule. Details of each species may be available through the relevant internal links. Synonyms may be listed where useful. 
  • 931
  • 09 Nov 2022
Topic Review
Pathophysiological Response to CnTX Voltage-Gated Channel Modulation
Voltage-gated ion channels are plasma membrane proteins that generate electrical signals following a change in the membrane voltage.
  • 903
  • 14 Jun 2022
Topic Review
Marine Chitin/Chitosan and Collagen Value Chains
Chitin/chitosan and collagen are two of the most important bioactive compounds, with applications in the pharmaceutical, veterinary, nutraceutical, cosmetic, biomaterials, and other industries. When extracted from non-edible parts of fish and shellfish, by-catches, and invasive species, their use contributes to a more sustainable and circular economy. 
  • 880
  • 06 Dec 2023
Topic Review
Seagrass
ٍSeagrass is a type of aquatic plants that grow in a wide variety of marine habitats. Seagrasses are specifically adapted to thrive in shallow and transparent seawater environments to access ample sunlight for their photosynthetic processes. This unique botanical group plays a crucial ecological role in coastal ecosystems and is distinguishable from macroalgae due to its vascular plant characteristics and its capacity to form underwater meadows in coastal waters.
  • 871
  • 07 Nov 2023
Topic Review
Population Genomics of Megalobrama
Megalobrama is the economically most important freshwater fish genus in China. Germplasm resources of Megalobrama have been depleting as a result of environmental degradation and artificial factors. By using population genomics, the genetic information of species diversity can be established with the advent of high-throughput sequencing. Researchers established the whole genome database of Megalobrama populations using the whole genome re-sequencing technology, explored population genetic structure, and inferred comprehensive evolutionary relationships using principal component analysis and population structure analysis. 
  • 864
  • 14 Feb 2022
Topic Review
Symbiotic Bacillota (Firmicutes) of Marine Macroalgae
The shift from the terrestrial to the marine environment to discover natural products has given rise to novel bioactive compounds, some of which have been approved for human medicine. However, the ocean, which makes up nearly three-quarters of the Earth’s surface, contains macro- and microorganisms whose natural products are yet to be explored. Among these underexplored marine organisms are macroalgae and their symbiotic microbes, such as Bacillota, a phylum of mostly Gram-positive bacteria previously known as Firmicutes. Macroalgae-associated Bacillota often produce chemical compounds that protect them and their hosts from competitive and harmful rivals.
  • 851
  • 13 Nov 2023
Topic Review
Marine Actinomycetes Antifouling Agents
Marine actinomycetes produce a multitude of active metabolites, some of which acquire antifouling properties. These antifouling compounds have chemical structures that fall under the terpenoids, polyketides, furanones, and alkaloids chemical groups. These compounds demonstrate eminent antimicrobial vigor associated with antiquorum sensing and antibiofilm potentialities against both Gram-positive and -negative bacteria. They have also constrained larval settlements and the acetylcholinesterase enzyme, suggesting a strong anti-macrofouling activity. Despite their promising in vitro and in vivo biological activities, scaled-up production of natural antifouling agents retrieved from marine actinomycetes remains inapplicable and challenging. This might be attributed to their relatively low yield, the unreliability of in vitro tests, and the need for optimization before scaled-up manufacturing. 
  • 835
  • 06 Nov 2023
Topic Review
Interactions of Toxic Cyanobacteria with Other Aquatic Microbes
Water resources are critically important, but also pose risks of exposure to toxic and pathogenic microbes. Toxic cyanobacteria have been linked to the death and disease of humans, domesticated animals, and wildlife in freshwater systems worldwide. Management approaches successful at reducing cyanobacterial abundance and toxin production have tended to be short-term solutions applied on small scales (e.g., algaecide application) or solutions that entail difficult multifaceted investments (e.g., modification of landscape and land use to reduce nutrient inputs). 
  • 825
  • 31 Jan 2023
Topic Review
Molecular Tools for Microbial Carbonates
Molecular methods have successfully characterized the overall community composition of mats, pinpointed microbes involved in key metabolisms, and revealed patterns in the distributions of microbial groups and functional genes. Two promising future directions include “zooming in” to assess the roles of specific organisms, microbial groups, and surfaces in carbonate biomineralization and “zooming out” to consider broader spans of space and time. A middle ground between the two can include model systems that contain representatives of important microbial groups, processes, and metabolisms in mats and simplify visualization and hypothesis testing. These directions will benefit from expanding reference datasets of marine microbes and enzymes and enrichments of representative microbes from mats. Such applications of molecular tools should increase the utility of ancient and modern microbialites as long-term recorders of microbial processes and environmental chemistry and improve modern applications of microbial mineralization.
  • 817
  • 13 May 2022
Topic Review
Natural Products from Plants and Algae
Neurodegenerative disorders including Parkinson’s disease (PD), Huntington’s disease (HD) and the most frequent, Alzheimer’s disease (AD), represent one of the most urgent medical needs worldwide. Despite a significantly developed understanding of disease development and pathology, treatments that stop AD progression are not yet available. The approval of sodium oligomannate (GV-971) for AD treatment in China emphasized the potential value of natural products for the treatment of neurodegenerative disorders. Many current clinical studies include the administration of a natural compound as a single and combination treatment. The most prominent mechanisms of action are anti-inflammatory and anti-oxidative activities, thus preserving cellular survival. 
  • 806
  • 01 Jun 2022
Topic Review
Improve Ulva Biomass Yield and Composition
Sea lettuce (Ulva spp.), with its worldwide distribution and remarkable ability to grow rapidly under various conditions, represents an important natural resource that is still under-exploited. Its biomass can be used for a wide range of applications in the food/feed, pharmaceutical, nutraceutical, biofuel, and bioremediation industries. However, its biochemical composition varies significantly according to the strains, species, environmental conditions, and likely other factors, such as its associated microbiome. Environmental growth conditions are thought to be the main factor influencing the composition of seaweed but recent reports show that natural variation for growth performance and biochemical composition within this genus is huge, around five fold for most phenotypic traits. Moreover, Ulva can be considered a holobiont with its associated microbiome which is necessary for the proper development of the organs (rhyzoids and thalli). Hence it is also likely that the microbiome is influencing growth and biochemical composition as well. 
  • 783
  • 23 Nov 2022
Topic Review
Baltic Sea Keystone Macroalgae (Fucus vesiculosus, Phaeophyceae)
The brown seaweed Fucus vesiculosus is the dominant and the most ecologically crucial primary producer and habitat founder in the Baltic Sea. In the shallow coastal zone, F. vesiculosus is particularly exposed to strongly and rapidly changing environmental conditions due to global change. 
  • 773
  • 12 Jan 2022
Topic Review
Biomolecular Composition of Sea Ice Microalgae
Microalgae growing on the underside of sea ice are key primary producers in polar marine environments. Their nutritional status, determined by their macromolecular composition, contributes to the region’s biochemistry and the unique temporal and spatial characteristics of their growth makes them essential for sustaining polar marine food webs. The importance of sea ice microalgae as primary producers in polar marine ecosystems means that ongoing research into climate-change driven macromolecular phenotyping is critical to understanding the implications for the regions biochemical cycling and carbon transfer. 
  • 767
  • 24 Jan 2022
Topic Review
North Atlantic Right Whale (Eubalaena glacialis) Welfare
Welfare assessments have been largely successful in improving management and quality of life for animals in human care. This has prompted an increased interest in their use for free-ranging wild animals to assess health, environment, and human-induced impacts that influence policy decisions. The North Atlantic Right Whale (NARW, Eubalaena glacialis) is one of the most endangered whale species. NARWs constantly face serious injuries and mortalities due to human activities, which poses both a species conservation and an individual welfare concern. Establishing a standardized welfare assessment for the NARW is a holistic way to understand the cumulative effects of anthropogenic activities at both the individual and population levels.
  • 755
  • 29 Dec 2021
Topic Review
Shellfish as Biosensors
The use of biological objects in monitoring the state of the environment and the changes caused by the impact of environmental pollution on marine and fresh waters is a promising tool due to a lower cost in comparison to traditional monitoring and the ability to receive immediate information about the ecosystem status. Since the mid-1980s, Russian specialists have developed online biomonitoring systems; as in the rest of world, there are two main approaches that are currently applied to study the physiological status of potential biosensor shellfish species and to monitor freshwater and marine systems: valvometry (registration of gaping activity in bivalve mollusks) and photoplethysmography (registration of cardiac activity in mollusks and crustaceans).
  • 694
  • 16 Feb 2023
Topic Review
Predatory and Defensive Strategies in Cone Snails
Cone snails are specialized carnivorous marine mollusks that can be found in coral reef areas, from shallow intertidal to deeper waters, and spread across the tropical Indian, Pacific, and Atlantic Oceans. They are classified as gastropods within the Conidae family, which feature hollow radular teeth and venom glands. They use a complex venom mixture to paralyze and hunt fish, mollusks, and worms.
  • 693
  • 06 Mar 2024
Topic Review
Lectins as Toxins from Marine Animals
Due to their remarkable structural diversity, glycans play important roles as recognition molecules on cell surfaces of living organisms. Carbohydrates exist in numerous isomeric forms and can adopt diverse structures through various branching patterns. Despite their relatively small molecular weights, they exhibit extensive structural diversity. On the other hand, lectins, also known as carbohydrate-binding proteins, not only recognize and bind to the diverse structures of glycans but also induce various biological reactions based on structural differences. Initially discovered as hemagglutinins in plant seeds, lectins have been found to play significant roles in cell recognition processes in higher vertebrates. 
  • 624
  • 13 Jul 2023
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