scholarly journals A Review of Starch Biosynthesis in Relation to the Building Block-Backbone Model

2020 ◽  
Vol 21 (19) ◽  
pp. 7011
Author(s):  
Ian J. Tetlow ◽  
Eric Bertoft
Keyword(s):  
Self Assembly ◽  
Building Block ◽  
Current Knowledge ◽  
Abiotic Factors ◽  
Practical Importance ◽  
Starch Biosynthesis ◽  
Starch Structure ◽  
Insoluble Polymer ◽  
Carbon Stores

Starch is a water-insoluble polymer of glucose synthesized as discrete granules inside the stroma of plastids in plant cells. Starch reserves provide a source of carbohydrate for immediate growth and development, and act as long term carbon stores in endosperms and seed tissues for growth of the next generation, making starch of huge agricultural importance. The starch granule has a highly complex hierarchical structure arising from the combined actions of a large array of enzymes as well as physicochemical self-assembly mechanisms. Understanding the precise nature of granule architecture, and how both biological and abiotic factors determine this structure is of both fundamental and practical importance. This review outlines current knowledge of granule architecture and the starch biosynthesis pathway in relation to the building block-backbone model of starch structure. We highlight the gaps in our knowledge in relation to our understanding of the structure and synthesis of starch, and argue that the building block-backbone model takes accurate account of both structural and biochemical data.

scholarly journals The role of biotic forces in driving macroevolution: beyond the Red Queen

2015 ◽  
Vol 282 (1808) ◽  
pp. 20150186 ◽  
Author(s):  
Kjetil L. Voje ◽  
Øistein H. Holen ◽  
Lee Hsiang Liow ◽  
Nils Chr. Stenseth
Keyword(s):  
Current Knowledge ◽  
Abiotic Factors ◽  
Empirical Work ◽  
Theoretical Work ◽  
Long Term Evolution ◽  
Red Queen Hypothesis ◽  
Red Queen ◽  
Extinction Rates ◽  
Term Evolution

A multitude of hypotheses claim that abiotic factors are the main drivers of macroevolutionary change. By contrast, Van Valen's Red Queen hypothesis is often put forward as the sole representative of the view that biotic forcing is the main evolutionary driver. This imbalance of hypotheses does not reflect our current knowledge: theoretical work demonstrates the plausibility of biotically driven long-term evolution, whereas empirical work suggests a central role for biotic forcing in macroevolution. We call for a more pluralistic view of how biotic forces may drive long-term evolution that is compatible with both phenotypic stasis in the fossil record and with non-constant extinction rates. Promising avenues of research include contrasting predictions from relevant theories within ecology and macroevolution, as well as embracing both abiotic and biotic proxies while modelling long-term evolutionary data. By fitting models describing hypotheses of biotically driven macroevolution to data, we could dissect their predictions and transcend beyond pattern description, possibly narrowing the divide between our current understanding of micro- and macroevolution.

Understanding storage starch biosynthesis in plants: a means to quality improvement

2006 ◽  
Vol 84 (8) ◽  
pp. 1167-1185 ◽  
Author(s):  
Ian J. Tetlow
Keyword(s):  
Quality Improvement ◽  
Biosynthetic Pathway ◽  
Current Knowledge ◽  
Industrial Applications ◽  
Starch Biosynthesis ◽  
Starch Structure ◽  
Granule Structure ◽  
The Many ◽  
A Current ◽  
Storage Starch

The many varied uses of starch in food and industrial applications often requires an understanding of its physicochemical properties and the detailed variations in granule structure that underpin these properties. The ability to manipulate storage starch structures depends on understanding the biosynthetic pathway, and in particular, how the many components of the pathway are coordinated and regulated. This article presents a current overview of starch structure and the known enzymes involved in the synthesis of the granule, with an emphasis on how current knowledge on the regulation of the pathway in cereals and other crops may be applied to the production of different functional starches.

scholarly journals High-efficiency CO2 separation using hybrid LDH-polymer membranes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaozhi Xu ◽  
Jiajie Wang ◽  
Awu Zhou ◽  
Siyuan Dong ◽  
Kaiqiang Shi ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Efficiency ◽  
Transmission Rate ◽  
Spray Coating ◽  
Separation Performance ◽  
Pdms Layer ◽  
Operational Testing ◽  
Enhanced Solubility ◽  
Double Hydroxide

AbstractMembrane-based gas separation exhibits many advantages over other conventional techniques; however, the construction of membranes with simultaneous high selectivity and permeability remains a major challenge. Herein, (LDH/FAS)n-PDMS hybrid membranes, containing two-dimensional sub-nanometre channels were fabricated via self-assembly of unilamellar layered double hydroxide (LDH) nanosheets and formamidine sulfinic acid (FAS), followed by spray-coating with a poly(dimethylsiloxane) (PDMS) layer. A CO2 transmission rate for (LDH/FAS)25-PDMS of 7748 GPU together with CO2 selectivity factors (SF) for SF(CO2/H2), SF(CO2/N2) and SF(CO2/CH4) mixtures as high as 43, 86 and 62 respectively are observed. The CO2 permselectivity outperforms most reported systems and is higher than the Robeson or Freeman upper bound limits. These (LDH/FAS)n-PDMS membranes are both thermally and mechanically robust maintaining their highly selective CO2 separation performance during long-term operational testing. We believe this highly-efficient CO2 separation performance is based on the synergy of enhanced solubility, diffusivity and chemical affinity for CO2 in the sub-nanometre channels.

scholarly journals Impact of mobile stroke units

2021 ◽  
pp. jnnp-2020-324005
Author(s):  
Klaus Fassbender ◽  
Fatma Merzou ◽  
Martin Lesmeister ◽  
Silke Walter ◽  
Iris Quasar Grunwald ◽  
...  
Keyword(s):  
Cost Efficiency ◽  
Current Knowledge ◽  
Vascular Imaging ◽  
Vessel Occlusion ◽  
Stroke Units ◽  
Stroke Treatment ◽  
Stroke Research ◽  
Mobile Stroke Unit ◽  
Novel Strategy

Since its first introduction in clinical practice in 2008, the concept of mobile stroke unit enabling prehospital stroke treatment has rapidly expanded worldwide. This review summarises current knowledge in this young field of stroke research, discussing topics such as benefits in reduction of delay before treatment, vascular imaging-based triage of patients with large-vessel occlusion in the field, differential blood pressure management or prehospital antagonisation of anticoagulants. However, before mobile stroke units can become routine, several questions remain to be answered. Current research, therefore, focuses on safety, long-term medical benefit, best setting and cost-efficiency as crucial determinants for the sustainability of this novel strategy of acute stroke management.

scholarly journals Cardiac Cell Therapy: Insights into the Mechanisms of Tissue Repair

2021 ◽  
Vol 22 (3) ◽  
pp. 1201
Author(s):  
Hsuan Peng ◽  
Kazuhiro Shindo ◽  
Renée R. Donahue ◽  
Ahmed Abdel-Latif
Keyword(s):  
Stem Cell ◽  
Immune Responses ◽  
Tissue Repair ◽  
Molecular Mechanisms ◽  
Clinical Evidence ◽  
Current Knowledge ◽  
Cell Delivery ◽  
Cardiac Cell Therapy ◽  
Stem Cell Treatment

Stem cell-based cardiac therapies have been extensively studied in recent years. However, the efficacy of cell delivery, engraftment, and differentiation post-transplant remain continuous challenges and represent opportunities to further refine our current strategies. Despite limited long-term cardiac retention, stem cell treatment leads to sustained cardiac benefit following myocardial infarction (MI). This review summarizes the current knowledge on stem cell based cardiac immunomodulation by highlighting the cellular and molecular mechanisms of different immune responses to mesenchymal stem cells (MSCs) and their secretory factors. This review also addresses the clinical evidence in the field.

scholarly journals Hymenoptera Venom Immunotherapy: Immune Mechanisms of Induced Protection and Tolerance

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1575
Author(s):  
Ajda Demšar Luzar ◽  
Peter Korošec ◽  
Mitja Košnik ◽  
Mihaela Zidarn ◽  
Matija Rijavec
Keyword(s):  
Current Knowledge ◽  
Allergic Diseases ◽  
Hymenoptera Venom ◽  
Venom Immunotherapy ◽  
Effector Cells ◽  
Immune Mechanisms ◽  
Protection Mechanisms ◽  
Sting Challenge ◽  
Effectiveness Data

Hymenoptera venom allergy is one of the most severe allergic diseases, with a considerable prevalence of anaphylactic reaction, making it potentially lethal. In this review, we provide an overview of the current knowledge and recent findings in understanding induced immune mechanisms during different phases of venom immunotherapy. We focus on protection mechanisms that occur early, during the build-up phase, and on the immune tolerance, which occurs later, during and after Hymenoptera venom immunotherapy. The short-term protection seems to be established by the early desensitization of mast cells and basophils, which plays a crucial role in preventing anaphylaxis during the build-up phase of treatment. The early generation of blocking IgG antibodies seems to be one of the main reasons for the lower activation of effector cells. Long-term tolerance is reached after at least three years of venom immunotherapy. A decrease in basophil responsiveness correlates with tolerated sting challenge. Furthermore, the persistent decline in IgE levels and, by monitoring the cytokine profiles, a shift from a Th2 to Th1 immune response, can be observed. In addition, the generation of regulatory T and B cells has proven to be essential for inducing allergen tolerance. Most studies on the mechanisms and effectiveness data have been obtained during venom immunotherapy (VIT). Despite the high success rate of VIT, allergen tolerance may not persist for a prolonged time. There is not much known about immune mechanisms that assure long-term tolerance post-therapy.

scholarly journals Management of Myositis-Associated Interstitial Lung Disease

Medicina ◽  
2021 ◽  
Vol 57 (4) ◽  
pp. 347
Author(s):  
Tomoyuki Fujisawa
Keyword(s):  
Interstitial Lung Disease ◽  
Lung Disease ◽  
Current Knowledge ◽  
Strong Predictor ◽  
Calcineurin Inhibitors ◽  
Pulmonary Involvement ◽  
Trna Synthetase ◽  
Evidence Based Guidelines ◽  
Substantial Heterogeneity

Idiopathic inflammatory myopathies, including polymyositis (PM), dermatomyositis (DM), and clinically amyopathic DM (CADM), are a diverse group of autoimmune diseases characterized by muscular involvement and extramuscular manifestations. Interstitial lung disease (ILD) has major pulmonary involvement and is associated with increased mortality in PM/DM/CADM. The management of PM-/DM-/CADM-associated ILD (PM/DM/CADM-ILD) requires careful evaluation of the disease severity and clinical subtype, including the ILD forms (acute/subacute or chronic), because of the substantial heterogeneity of their clinical courses. Recent studies have highlighted the importance of myositis-specific autoantibodies’ status, especially anti-melanoma differentiation-associated gene 5 (MDA5) and anti-aminoacyl tRNA synthetase (ARS) antibodies, in order to evaluate the clinical phenotypes and treatment of choice for PM/DM/CADM-ILD. Because the presence of the anti-MDA5 antibody is a strong predictor of a worse prognosis, combination treatment with glucocorticoids (GCs) and calcineurin inhibitors (CNIs; tacrolimus (TAC) or cyclosporin A (CsA)) is recommended for patients with anti-MDA5 antibody-positive DM/CADM-ILD. Rapidly progressive DM/CADM-ILD with the anti-MDA5 antibody is the most intractable condition, which requires immediate combined immunosuppressive therapy with GCs, CNIs, and intravenous cyclophosphamide. Additional salvage therapies (rituximab, tofacitinib, and plasma exchange) should be considered for patients with refractory ILD. Patients with anti-ARS antibody-positive ILD respond better to GC treatment, but with frequent recurrence; thus, GCs plus immunosuppressants (TAC, CsA, azathioprine, and mycophenolate mofetil) are often needed in order to achieve favorable long-term disease control. PM/DM/CADM-ILD management is still a therapeutic challenge for clinicians, as evidence-based guidelines do not exist to help with management decisions. A few prospective clinical trials have been recently reported regarding the treatment of PM/DM/CADM-ILD. Here, the current knowledge on the pharmacologic managements of PM/DM/CADM-ILD was mainly reviewed.

scholarly journals COVID-19 Infection during Pregnancy: Risk of Vertical Transmission, Fetal, and Neonatal Outcomes

2021 ◽  
Vol 11 (6) ◽  
pp. 483
Author(s):  
Marwa Saadaoui ◽  
Manoj Kumar ◽  
Souhaila Al Khodor
Keyword(s):  
Pregnant Women ◽  
Vertical Transmission ◽  
Current Knowledge ◽  
Limited Data ◽  
Pregnancy Risk ◽  
Public Health Challenge ◽  
Short And Long Term ◽  
Critical Public Health ◽  
The Impact

The COVID-19 pandemic is a worldwide, critical public health challenge and is considered one of the most communicable diseases that the world had faced so far. Response and symptoms associated with COVID-19 vary between the different cases recorded, but it is amply described that symptoms become more aggressive in subjects with a weaker immune system. This includes older subjects, patients with chronic diseases, patients with immunosuppression treatment, and pregnant women. Pregnant women are receiving more attention not only because of their altered physiological and immunological function but also for the potential risk of viral vertical transmission to the fetus or infant. However, very limited data about the impact of maternal infection during pregnancy, such as the possibility of vertical transmission in utero, during birth, or via breastfeeding, is available. Moreover, the impact of infection on the newborn in the short and long term remains poorly understood. Therefore, it is vital to collect and analyze data from pregnant women infected with COVID-19 to understand the viral pathophysiology during pregnancy and its effects on the offspring. In this article, we review the current knowledge about pre-and post-natal COVID-19 infection, and we discuss whether vertical transmission takes place in pregnant women infected with the virus and what are the current recommendations that pregnant women should follow in order to be protected from the virus.

scholarly journals Role of Glucose-Lowering Medications in Erectile Dysfunction

2021 ◽  
Vol 10 (11) ◽  
pp. 2501
Author(s):  
Angelo Cignarelli ◽  
Valentina Annamaria Genchi ◽  
Rossella D’Oria ◽  
Fiorella Giordano ◽  
Irene Caruso ◽  
...  
Keyword(s):  
Erectile Dysfunction ◽  
Current Knowledge ◽  
Smooth Muscle Contractility ◽  
Glucose Lowering ◽  
Glycation End Products ◽  
Altered Metabolism

Erectile dysfunction (ED) is a long-term complication of type 2 diabetes (T2D) widely known to affect the quality of life. Several aspects of altered metabolism in individuals with T2D may help to compromise the penile vasculature structure and functions, thus exacerbating the imbalance between smooth muscle contractility and relaxation. Among these, advanced glycation end-products and reactive oxygen species derived from a hyperglycaemic state are known to accelerate endothelial dysfunction by lowering nitric oxide bioavailability, the essential stimulus of relaxation. Although several studies have explained the pathogenetic mechanisms involved in the generation of erectile failure, few studies to date have described the efficacy of glucose-lowering medications in the restoration of normal sexual activity. Herein, we will present current knowledge about the main starters of the pathophysiology of diabetic ED and explore the role of different anti-diabetes therapies in the potential remission of ED, highlighting specific pathways whose activation or inhibition could be fundamental for sexual care in a diabetes setting.

scholarly journals Health and sustainability of glaciers in High Mountain Asia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evan Miles ◽  
Michael McCarthy ◽  
Amaury Dehecq ◽  
Marin Kneib ◽  
Stefan Fugger ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Field Measurements ◽  
Tien Shan ◽  
High Mountain ◽  
Specific Mass ◽  
Ice Flow ◽  
Ice Volume ◽  
Mass Redistribution ◽  
Glacier Ablation

AbstractGlaciers in High Mountain Asia generate meltwater that supports the water needs of 250 million people, but current knowledge of annual accumulation and ablation is limited to sparse field measurements biased in location and glacier size. Here, we present altitudinally-resolved specific mass balances (surface, internal, and basal combined) for 5527 glaciers in High Mountain Asia for 2000–2016, derived by correcting observed glacier thinning patterns for mass redistribution due to ice flow. We find that 41% of glaciers accumulated mass over less than 20% of their area, and only 60% ± 10% of regional annual ablation was compensated by accumulation. Even without 21st century warming, 21% ± 1% of ice volume will be lost by 2100 due to current climatic-geometric imbalance, representing a reduction in glacier ablation into rivers of 28% ± 1%. The ablation of glaciers in the Himalayas and Tien Shan was mostly unsustainable and ice volume in these regions will reduce by at least 30% by 2100. The most important and vulnerable glacier-fed river basins (Amu Darya, Indus, Syr Darya, Tarim Interior) were supplied with >50% sustainable glacier ablation but will see long-term reductions in ice mass and glacier meltwater supply regardless of the Karakoram Anomaly.

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