scholarly journals Iron-binding ligands and their role in the ocean biogeochemistry of iron

2007 ◽  
Vol 4 (4) ◽  
pp. 221 ◽  
Author(s):  
Keith A. Hunter ◽  
Philip W. Boyd
Keyword(s):  
Mixed Layer ◽  
Current Knowledge ◽  
Deep Ocean ◽  
Biologically Active ◽  
Global Ocean ◽  
Future Research ◽  
Iron Binding ◽  
Marine Microbes ◽  
Geological Time ◽  
Eukaryotic Organisms

Environmental context. It is now well accepted that iron is an essential micronutrient for phytoplankton growth in many areas of the global ocean, even though this element is present in seawater in extremely low abundance. It is also known that most of the iron in seawater is present as complexes formed with ligands of natural organic matter whose nature and origin remain largely unknown. Here we consider how these iron-complexing ligands might have evolved during geological time, what factors may have given rise to their presence and the possible roles that they play in iron biogeochemistry. Abstract. Current knowledge about the role of iron-binding organic ligands in the ocean and their role in determining the biogeochemistry of this biologically active element has been summarised. Some electrochemical measurements suggest the presence of at least two ligand types, a strong binding ligand L1 found mainly in the mixed layer and a weaker ligand L2 found mainly in deep water. Speciation of FeIII is dominated by L1 in the mixed layer and L2 in the deep ocean. There is some evidence that L1 is siderophore-like and is specifically generated by marine microbes (i.e. heterotropic bacteria and cyanobacteria). We suggest that this is a specific biological mechanism for sequestering iron in the mixed layer that developed early in the ocean’s history (Archaean period, 2500–3500 million years BP), whereas the more ubiquitous L2 ligand only arose at the close of the Proterozoic (500–2500 million years BP) when eukaryotic organisms evolved to switch on the ocean’s biological pump, allowing L2 ligands to form from the oxidation of sinking biological particles. This development coincided with the complete oxygenation of the ocean’s interior which removed the iron-binding sulfide ion and allowed maintenance of the ocean’s iron inventory. These speculations are accompanied by various suggestions about avenues for future research to better understand iron biogeochemistry.

Effects of Ocean Acidification on the Diversity and Activity of Heterotrophic Marine Microorganisms

2011 ◽  
Author(s):  
Markus G. Weinbauer ◽  
Xavier Mari
Keyword(s):  
Ocean Acidification ◽  
Relevant Literature ◽  
Global Ocean ◽  
Future Research ◽  
Marine Microorganisms ◽  
Marine Microbes ◽  
Ph Change ◽  
Cellular Life ◽  
Heterotrophic Microorganisms ◽  
Microbial Plankton

Microbe-mediated processes are crucial for biogeochemical cycles and the functioning of marine ecosystems (Azam and Malfatti 2007 ). If these processes are affected by ocean acidification, major consequences can be expected for the functioning of the global ocean and the systems that it influences, such as the atmosphere. In contrast to phytoplankton, which have been relatively well studied (see Chapter 6), there is comparatively little information on the effect of ocean acidification on heterotrophic microorganisms. Two reviews on the potential effects of ocean acidification on microbial plankton have recently been published (Liu et al. 2010 ; Joint et al. 2011) . In a recent perspective paper, Joint et al. (2011) concluded that marine microbes possess the flexibility to accommodate pH change and that major changes in marine biogeochemical processes that are driven by microorganisms are unlikely. Narrative reviews, which look at some of the relevant literature, are potentially biased and could lead to misleading conclusions (Gates 2002). Metaanalysis was developed to overcome most biases of narrative reviews. It statistically combines the results (effect size) of several studies that address a shared research hypothesis. Liu et al. (2010) used a metaanalytic approach to comprehensively review the current understanding of the effect of ocean acidification on microbes (including phytoplankton) and microbial processes, and to highlight the gaps that need to be addressed in future research. In the following, a brief digest on oceanic microbes and their role is provided for readers unfamiliar with this topic. Then the research that has been performed to assess the effects of ocean acidification on the diversity and activity of heterotrophic marine microorganisms is reviewed. Finally, scenarios are developed and potential implications are discussed. Microorganisms are defined as organisms that are microscopic, i.e. too small to be seen by the naked human eye, and mostly comprise single-celled organisms. Viruses are sometimes also included in this definition but it is hotly debated whether viruses are alive or not (Raoult and Forterre 2008). The current phylogeny considers three domains of cellular life, the Bacteria, the Archaea and the Eukarya.

The physiology of lactoferrin

2002 ◽  
Vol 80 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Jeremy H Brock
Keyword(s):  
Current Knowledge ◽  
Binding Protein ◽  
Biochemical Properties ◽  
Structure And Function ◽  
Iron Nutrition ◽  
Future Research ◽  
Iron Binding ◽  
Physiological Functions ◽  
Iron Binding Protein ◽  
And Function

This paper reviews our current knowledge of the structure and function of the iron-binding protein lactoferrin. In particular, it attempts to relate the various proposed physiological functions of lactoferrin to its most characteristic biochemical properties, i.e. its ability to bind iron and its highly basic nature. The extent to which various physiological functions can be considered as definitely established is critically reviewed, and suggestions for future research are proposed.Key words: lactoferrin, iron, nutrition, immunology, infection, inflammation.

scholarly journals The Fruit Malus prunifolia (Malus micromalus Mak.): A Minireview of Current Knowledge of Fruit Composition and Health Benefits

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Xiaolong Ji ◽  
Chunyan Hou ◽  
Xudan Guo
Keyword(s):  
Yellow River ◽  
Current Knowledge ◽  
Biological Activities ◽  
Biologically Active ◽  
Future Research ◽  
Active Components ◽  
Medicinal Uses ◽  
Malus Prunifolia ◽  
Rosaceae Family ◽  
Phytochemical Studies

The fruit Malus prunifolia (Malus micromalus Mak.), which belongs to the Rosaceae family, grows mostly in the upper-middle reaches of the Yellow River area. It has long been popular as a fruit commodity and as a natural remedy. Its main biologically active components include vitamin C, phenolics, flavonoids, polysaccharides, and triterpenic acids. Recent phytochemical studies on the fruit have shed some light on its biological activities, such as anticancer, immunomodulatory, antioxidant, immunostimulating, hepatoprotective, and gastrointestinal protective activities. A stronger focus on clinical studies and phytochemical characterization of the fruit will be essential for future research efforts. This minireview could be useful for predicting its other medicinal uses and its potential drug or food interactions, and it could be beneficial for people living in areas where the fruit is endemic and where healthcare resources are scarce.

Development of Intestinal Transport Function in Mammals

2000 ◽  
Vol 80 (4) ◽  
pp. 1633-1667 ◽  
Author(s):  
Jiří Pácha
Keyword(s):  
Intestinal Mucosa ◽  
Current Knowledge ◽  
Intestinal Transport ◽  
Intestinal Secretion ◽  
Intestinal Content ◽  
Transport Processes ◽  
Biologically Active ◽  
Future Research ◽  
Transport Function ◽  
Ontogenetic Changes

Considerable progress has been made over the last decade in the understanding of mechanisms responsible for the ontogenetic changes of mammalian intestine. This review presents the current knowledge about the development of intestinal transport function in the context of intestinal mucosa ontogeny. The review predominantly focuses on signals that trigger and/or modulate the developmental changes of intestinal transport. After an overview of the proliferation and differentiation of intestinal mucosa, data about the bidirectional traffic (absorption and secretion) across the developing intestinal epithelium are presented. The largest part of the review is devoted to the description of developmental patterns concerning the absorption of nutrients, ions, water, vitamins, trace elements, and milk-borne biologically active substances. Furthermore, the review examines the development of intestinal secretion that has a variety of functions including maintenance of the fluidity of the intestinal content, lubrication of mucosal surface, and mucosal protection. The age-dependent shifts of absorption and secretion are the subject of integrated regulatory mechanisms, and hence, the input of hormonal, nervous, immune, and dietary signals is reviewed. Finally, the utilization of energy for transport processes in the developing intestine is highlighted, and the interactions between various sources of energy are discussed. The review ends with suggestions concerning possible directions of future research.

scholarly journals Phytotherapeutic mechanism of medicinal plants with wound-healing potential: a mini-review

2021 ◽  
Author(s):  
Stephen EMMANUEL ◽  
Ademidun Adeola ADESIBIKAN ◽  
Oluwole Solomon OLADEJI
Keyword(s):  
Wound Healing ◽  
Medicinal Plants ◽  
Therapeutic Potential ◽  
Higher Plants ◽  
Current Knowledge ◽  
Biologically Active ◽  
Future Research ◽  
Therapeutic Effects ◽  
Active Metabolites ◽  
Closure Rate

The applications of medicinal plant species for diverse therapeutic effects are well documented throughout the world. In recent times, the screening of higher plants for unique biologically active compounds, particularly those with pronounced therapeutic potency, has received the interest of the science community. A wound is a loss or break in the anatomic stability of active tissue. It not only poses a physical and mental threat to zillions of people but could cause the failure of multiple organs, amputation, and even death. Therefore, thousands of plants have been screened to obtain active metabolites or compounds that can accelerate the process of restoring the damaged tissue structure and inhibit the probability of infections. Due to the severity of wounds to the human body, it is essential to explore safe, economical, and environmentally friendly therapeutics from nature. This review aims to conduct a comprehensive search of medicinal herbs to uncover their therapeutic potential, identify gaping holes, and assess future research prospects that could lead to the discovery of novel pharmacophores. Thus, the review is tailored towards the appraisals of phytotherapeutic mechanism and wound healing efficacy of medicinal plants, which will help spur future research and improve our current knowledge leading to the unearthing of novel and potent pharmacophores with pronounced wound healing potentials. Several medicinal plants with scientifically proven wound-healing activities are reported and discussed alongside phytochemicals present their various extracts and isolates. The achievable wound-healing closure rate of each plant was also reported with a focus on what is responsible for the healing rate.

On the impact of sea ice in a global ocean circulation model

1997 ◽  
Vol 25 ◽  
pp. 111-115 ◽  
Author(s):  
Achim Stössel
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ocean Circulation ◽  
General Circulation ◽  
Thermohaline Circulation ◽  
Circulation Model ◽  
Deep Ocean ◽  
Global Ocean ◽  
Convective Activity ◽  
The Impact

This paper investigates the long-term impact of sea ice on global climate using a global sea-ice–ocean general circulation model (OGCM). The sea-ice component involves state-of-the-art dynamics; the ocean component consists of a 3.5° × 3.5° × 11 layer primitive-equation model. Depending on the physical description of sea ice, significant changes are detected in the convective activity, in the hydrographic properties and in the thermohaline circulation of the ocean model. Most of these changes originate in the Southern Ocean, emphasizing the crucial role of sea ice in this marginally stably stratified region of the world's oceans. Specifically, if the effect of brine release is neglected, the deep layers of the Southern Ocean warm up considerably; this is associated with a weakening of the Southern Hemisphere overturning cell. The removal of the commonly used “salinity enhancement” leads to a similar effect. The deep-ocean salinity is almost unaffected in both experiments. Introducing explicit new-ice thickness growth in partially ice-covered gridcells leads to a substantial increase in convective activity, especially in the Southern Ocean, with a concomitant significant cooling and salinification of the deep ocean. Possible mechanisms for the resulting interactions between sea-ice processes and deep-ocean characteristics are suggested.

Amruthapala (Decalepis arayalpathra (J. Joseph and V. Chandras.) Venter): A Comprehensive Review on Diversity, Therapeutic Uses, and Valorization of Bioactive Constituents

2019 ◽  
Vol 20 (5) ◽  
pp. 376-389 ◽  
Author(s):  
Sonali Mishra ◽  
Nupur Srivastava ◽  
Velusamy Sundaresan ◽  
Karuna Shanker
Keyword(s):  
Secondary Metabolite ◽  
Current Knowledge ◽  
Experimental Studies ◽  
Critical Discussion ◽  
Future Research ◽  
Bioactive Constituents ◽  
Medicinal Uses ◽  
Comprehensive Review ◽  
Therapeutic Uses ◽  
Decalepis Arayalpathra

Background: Decalepis arayalpathra (J. Joseph and V. Chandras.) Venter is used primarily for nutrition besides its therapeutic values. Traditional preparations/formulations from its tuber are used as a vitalizer and blood purifier drink. The folklore medicinal uses cover inflammation, cough, wound healing, antipyretic, and digestive system management. A comprehensive review of the current understanding of the plant is required due to emerging concerns over its safety and efficacy. Objective: The systematic collection of the authentic information from different sources with the critical discussion is summarised in order to address various issues related to botanical identity, therapeutic medicine, nutritional usage, phytochemical, and pharmacological potentials of the D. arayalpathra. Current use of traditional systems of medicine can be used to expand future research opportunities. Materials and Methods: Available scripted information was collected manually, from peered review research papers and international databases viz. Science Direct, Google Scholar, SciFinder, Scopus, etc. The unpublished resources which were not available in database were collected through the classical books of ‘Ayurveda’ and ‘Siddha’ published in regional languages. The information from books, Ph.D. and MSc dissertations, conference papers and government reports were also collected. We thoroughly screened the scripted information of classical books, titles, abstracts, reports, and full-texts of the journals to establish the reliability of the content. Results: Tuber bearing vanilla like signature flavor is due to the presence of 2-hydroxy-4-methoxybenzaldehyde (HMB). Among five other species, Decalepis arayalpathra (DA) has come under the ‘critically endangered’ category, due to over-exploitation for traditional, therapeutic and cool drink use. The experimental studies proved that it possesses gastro-protective, anti-tumor, and antiinflammatory activities. Some efforts were also made to develop better therapeutics by logical modifications in 2-Hydroxy-4-methoxy-benzaldehyde, which is a major secondary metabolite of D. arayalpathra. ‘Amruthapala’ offers the enormous opportunity to develop herbal drink with health benefits like gastro-protective, anti-oxidant and anti-inflammatory actions. Results: The plant has the potential to generate the investigational new lead (IND) based on its major secondary metabolite i.e. 2-Hydroxy-4-methoxy-benzaldehyde. The present mini-review summarizes the current knowledge on Decalepis arayalpathra, covering its phytochemical diversity, biological potentials, strategies for its conservation, and intellectual property rights (IPR) status. Chemical Compounds: 2-hydroxy-4-methoxybenzaldehyde (Pubchem CID: 69600), α-amyrin acetate (Pubchem CID: 293754), Magnificol (Pubchem CID: 44575983), β-sitosterol (Pubchem CID: 222284), 3-hydroxy-p-anisaldehyde (Pubchem CID: 12127), Naringenin (Pubchem CID: 932), Kaempferol (Pubchem CID: 5280863), Aromadendrin (Pubchem CID: 122850), 3-methoxy-1,2-cyclopentanedione (Pubchem CID: 61209), p-anisaldehyde (Pubchem CID: 31244), Menthyl acetate (Pubchem CID: 27867), Benzaldehyde (Pubchem CID: 240), p-cymene (Pubchem CID: 7463), Salicylaldehyde (Pubchem CID: 6998), 10-epi-γ-eudesmol (Pubchem CID: 6430754), α -amyrin (Pubchem CID: 225688), 3-hydroxy-4-methoxy benzaldehyde (Pubchem CID: 12127).

Disparities in Health Between Black and White Americans: Current Knowledge and Directions for Future Research

2018 ◽  
pp. 456-478
Author(s):  
Thomas E. Fuller-Rowell ◽  
David S. Curtis ◽  
Adrienne M. Duke
Keyword(s):  
Health Disparities ◽  
Current Knowledge ◽  
Public Investment ◽  
The United States ◽  
Future Research ◽  
Sociocultural Factors ◽  
White Americans ◽  
Biological Mechanisms ◽  
Black And White ◽  
Racial Ethnic

Conceptual frameworks for racial/ethnic health disparities are abundant, but many have received insufficient empirical attention. As a result, there are substantial gaps in scientific knowledge and a range of untested hypotheses. Particularly lacking is specificity in behavioral and biological mechanisms for such disparities and their underlying social determinants. Alongside lack of political will and public investment, insufficient clarity in mechanisms has stymied efforts to address racial health disparities. Capitalizing on emergent findings from the Midlife in the United States (MIDUS) study and other longitudinal studies of aging, this chapter evaluates research on health disparities between black and white US adults. Attention is given to candidate behavioral and biological mechanisms as precursors to group differences in morbidity and mortality and to environmental and sociocultural factors that may underlie these mechanisms. Future research topics are discussed, emphasizing those that offer promise with respect to illuminating practical solutions to racial/ethnic health disparities.

scholarly journals Protocol for a systematic review on the experience of informal caregivers for people with a moderate to advanced dementia within a domestic home setting

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Charles James ◽  
Catherine Walshe ◽  
Katherine Froggatt
Keyword(s):  
Systematic Review ◽  
Negative Impact ◽  
Current Knowledge ◽  
Informal Caregivers ◽  
Informal Caregiving ◽  
Bibliographic Databases ◽  
Future Research ◽  
Advanced Dementia ◽  
Home Setting ◽  
Search Terms

Abstract Background The knowledge about the experience of informal caregivers who provide care to people with moderate to advanced dementia in a domestic home setting is limited. A consequence of long hours of caregiving in addition to dealing with normal challenges of daily living is their experience of a poor quality of life. Some of their experiences may be described in terms of a feeling of powerlessness to make changes during care provision. This feeling may also suggest an experience of moral distress. The aim of this systematic review is to synthesise qualitative evidence relating to these experiences. Methods This review adopts a narrative synthesis approach. A search will be conducted for studies written in the English language in the bibliographic databases MEDLINE Complete, CINAHL, EMBASE, PsycINFO, Web of Science and Academic Search Complete covering periods from 1984 to present. Included studies will be qualitative or mixed-methods designs. The search terms will be related to dementia and caregivers, and the process will be focused on dementia at the moderate to the advanced stages within the domestic home setting. Reference lists of included papers will also be searched for additional relevant citations. Search terms and strategies will be checked by two independent reviewers. The identification of abstracts and full texts of studies will be done by the author, while the quality and the risk of bias will also be checked by the two independent reviewers. Discussion Psychological distress is cited as an experience reported within informal caregiving. For the caregiver, it is associated with a negative impact on general health. To date, no synthesis exists on the specific experience of informal caregiving for people with moderate to advanced dementia within the domestic home setting. This review considers that variation of accounts contributes to how the informal caregivers’ general experience is explored in future research. This may enable gaps in current knowledge to be highlighted within the wider context of caregiving in the domestic home setting. Systematic review registration This review is registered with PROSPERO (CRD42020183649).

scholarly journals Molecular Mechanisms of Insulin Resistance in Polycystic Ovary Syndrome: Unraveling the Conundrum in Skeletal Muscle?

2019 ◽  
Vol 104 (11) ◽  
pp. 5372-5381 ◽  
Author(s):  
Nigel K Stepto ◽  
Alba Moreno-Asso ◽  
Luke C McIlvenna ◽  
Kirsty A Walters ◽  
Raymond J Rodgers
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Polycystic Ovary Syndrome ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Polycystic Ovary ◽  
Evidence Synthesis ◽  
Basic Research ◽  
Future Research ◽  
Ovary Syndrome

Abstract Context Polycystic ovary syndrome (PCOS) is a common endocrine condition affecting 8% to 13% of women across the lifespan. PCOS affects reproductive, metabolic, and mental health, generating a considerable health burden. Advances in treatment of women with PCOS has been hampered by evolving diagnostic criteria and poor recognition by clinicians. This has resulted in limited clinical and basic research. In this study, we provide insights into the current and future research on the metabolic features of PCOS, specifically as they relate to PCOS-specific insulin resistance (IR), that may affect the most metabolically active tissue, skeletal muscle. Current Knowledge PCOS is a highly heritable condition, yet it is phenotypically heterogeneous in both reproductive and metabolic features. Human studies thus far have not identified molecular mechanisms of PCOS-specific IR in skeletal muscle. However, recent research has provided new insights that implicate energy-sensing pathways regulated via epigenomic and resultant transcriptomic changes. Animal models, while in existence, have been underused in exploring molecular mechanisms of IR in PCOS and specifically in skeletal muscle. Future Directions Based on the latest evidence synthesis and technologies, researchers exploring molecular mechanisms of IR in PCOS, specifically in muscle, will likely need to generate new hypothesis to be tested in human and animal studies. Conclusion Investigations to elucidate the molecular mechanisms driving IR in PCOS are in their early stages, yet remarkable advances have been made in skeletal muscle. Overall, investigations have thus far created more questions than answers, which provide new opportunities to study complex endocrine conditions.

Sign in / Sign up

Export Citation Format

Share Document