Alloxan-induced diabetes reduces sarcolemmal Na+-K+ pump function in rabbit ventricular myocytes

The effect of diabetes on sarcolemmal Na⁺-K⁺ pump function is important for our understanding of heart disease associated with diabetes and design of its treatment. We induced diabetes characterized by hyperglycemia but no other major metabolic disturbances in rabbits. Ventricular myocytes isolated from diabetic rabbits and controls were voltage clamped and internally perfused with the whole cell patch-clamp technique. Electrogenic Na⁺-K⁺ pump current (I_p, arising from the 3:2 Na⁺-to-K⁺ exchange ratio) was identified as the shift in holding current induced by Na⁺-K⁺ pump blockade with 100 µmol/l ouabain in most experiments. There was no effect of diabetes on I_p recorded when myocytes were perfused with pipette solutions containing 80 mmol/l Na⁺ to nearly saturate intracellular Na⁺-K⁺ pump sites. However, diabetes was associated with a significant decrease in I_p measured when pipette solutions contained 10 mmol/l Na⁺. The decrease was independent of membrane voltage but dependent on the intracellular concentration of K⁺. There was no effect of diabetes on the sensitivity of I_p to extracellular K⁺. Pump inhibition was abolished by restoration of euglycemia or by in vivo angiotensin II receptor blockade with losartan. We conclude that diabetes induces sarcolemmal Na⁺-K⁺ pump inhibition that can be reversed with pharmacological intervention. sodium transport; insulin; angiotensin II; cardiomyopathy; hyperglycemia     

Capacity for Infectious HIV-1 Virion Capture Differs by Envelope Antibody Specificity

Antibody capacity to recognize infectious virus is a prerequisite of many antiviral functions. We determined the infectious virion capture index (IVCI) of different antibody specificities. Whereas broadly neutralizing antibodies (bNAbs), except for an MPER bNAb, selectively captured infectious virions, non-bNAbs and mucosal human immunodeficiency virus type 1 (HIV-1)-positive IgG captured subsets of both infectious and noninfectious virions. Infectious virion capture was additive with a mixture of antibodies, providing proof of concept for vaccine-induced antibodies that together have improved capacity to recognize infectious virions.     

Urokinase-type plasminogen activator and arthritis progression: role in systemic disease with immune complex involvement

Introduction  

Urokinase-type plasminogen activator (u-PA) has been implicated in fibrinolysis, cell migration, latent cytokine activation, cell activation, T-cell activation, and tissue remodeling, all of which are involved in the development of rheumatoid arthritis. Previously, u-PA has been reported to play a protective role in monoarticular arthritis models involving mBSA as the antigen, but a deleterious role in the systemic polyarticular collagen-induced arthritis (CIA) model. The aim of the current study is to determine how u-PA might be acting in systemic arthritis models.     

What motivates ecological restoration?

Ecological restoration projects are motivated by diverse environmental and social reasons. Motivations likely vary between stakeholders or regions, and influence the approach taken to plan, implement, and monitor restoration projects. We surveyed 307 people involved in the restoration of native vegetation across Australia to identify their underlying motivations. We also elicited information on planning, implementation, and monitoring of restoration projects. We found that biodiversity enhancement is the main motivation for undertaking restoration, with biodiversity offsetting, water quality improvements, and social reasons as important secondary motivations. Motivations varied significantly by stakeholder type and region. Restoration projects primarily motivated by ecosystem service provision (e.g. water quality improvements and social reasons) sought less pristine ecological outcomes than projects motivated by biodiversity enhancement or offsetting. Rigorous monitoring designs (e.g. quantitative, repeatable surveys, and use of performance indicators) were rarely used in restoration projects, except for projects motivated by scientific research. Better alignment of different restoration motivations with the planning and monitoring of restoration projects should deliver greater benefits through setting appropriate objectives and evaluating outcomes against these objectives. These improvements will increase the capacity of the restoration practice to meet international biodiversity commitments and communicate restoration outcomes to stakeholders.     

Assisted natural regeneration accelerates recovery of highly disturbed rainforest

Large areas of rainforests in Australia and other tropical regions have been extensively cleared since the mid‐19th century. As abandoned agro‐pastoral land becomes increasingly prominent, there is an ongoing need to identify cost‐effective approaches to reinstate forest on these landscapes. Assisted regeneration is a potentially lower cost restoration approach which aims to accelerate forest recovery by removing barriers to natural regeneration. However, despite being widely used its ecological benefits are poorly quantified, particularly on long cleared and grazed land. This study quantified the benefits of assisted regeneration on previously cleared land in a subtropical rainforest ecosystem within eastern Australia. Three different site types were used (grazed, grazing excluded and grazing excluded plus assisted regeneration, each with a maximum distance of 120 m to remnant forest) to compare forest recovery up to 10 years after grazing was relieved with and without 4–6 years of assisted regeneration. Assisted regeneration sites showed a threefold increase in canopy cover, fourfold increase in native tree and shrub species richness and over 40 times greater native stem density compared to nonassisted regeneration sites. Stimulation of native recruitment appears dependent on the simultaneous removal of multiple barriers to regeneration, with the exclusion of grazing alone insufficient. This demonstrates the additional ecological benefits arising from investment in assisted regeneration. It offers considerable promise as a cost‐effective tool for accelerating and improving reinstatement of forest on retired agro‐pastoral land in the humid subtropics.     

Towards Miscanthus combustion quality improvement: the role of flowering and senescence

In commercially grown Miscanthus × giganteus, despite imposing a yield penalty, postwinter harvests improve quality criteria for thermal conversion and crop sustainability through remobilization of nutrients to the underground rhizome. We examined 16 Miscanthus genotypes with different flowering and senescence times for variation in N, P, K, moisture, ash, Cl and Si contents, hypothesizing that early flowering and senescence could result in improved biomass quality and/or enable an earlier harvest of biomass (in autumn at peak yield). Ideal crop characteristics at harvest are low N and P to reduce future fertilizer inputs, low K and Cl to reduce corrosion in boilers, low moisture to reduce spoilage and transportation costs, and low Si and ash to reduce slagging and consequent operational downtime. Stems and leaves were harvested during summer, autumn and then the following spring after overwinter ripening. In spring, stem contents of N were 30–60 mg kg^?1, P were 203–1132 mg kg^?1, K were 290–4098 mg kg^?1, Cl were 10–23 mg kg^?1 and moisture were 12–38%. Notably, late senescence resulted in increased N, P, K, Cl, moisture and ash contents, and should therefore be avoided for thermochemical conversion. Flowering and senescence led to overall improved combustion quality, where flowered genotypes tended towards lower P, K, Cl and moisture contents; marginally less, or similar, N, Si and ash contents; and a similar higher heating value, compared to those that had not flowered. Such genotypes could potentially be harvested in the autumn. However, one genotype that did not flower in our trial exhibited sufficiently low N and K content in autumn to meet the ENplus wood pellet standards for those traits, and some of the lowest P, moisture and ash contents in our trial, and is thus a target for future research and breeding.     

Multiplex knockout of trichome-regulating MYB duplicates in hybrid poplar using a single gRNA

As the focus for CRISPR/Cas-edited plants moves from proof-of-concept to real-world applications, precise gene manipulation will increasingly require concurrent multiplex editing for polygenic traits. A common approach for editing across multiple sites is to design one guide RNA (gRNA) per target; however, this complicates construct assembly and increases the possibility of off-target mutations. In this study, we utilized one gRNA to target MYB186, a known positive trichome regulator, as well as its paralogs MYB138 and MYB38 at a consensus site for mutagenesis in hybrid poplar (Populus tremula × P. alba INRA 717-1B4). Unexpected duplications of MYB186 and MYB138 resulted in eight alleles for the three targeted genes in the hybrid poplar. Deep sequencing and polymerase chain reaction analyses confirmed editing across all eight targets in nearly all of the resultant glabrous mutants, ranging from small indels to large genomic dropouts, with no off-target activity detected at four potential sites. This highlights the effectiveness of a single gRNA targeting conserved exonic regions for multiplex editing. Additionally, cuticular wax and whole-leaf analyses showed a complete absence of triterpenes in the trichomeless mutants, hinting at a previously undescribed role for the nonglandular trichomes of poplar.

Targeting conserved sequences with a single gRNA allows efficient mutagenesis of a multigene family and the recovery of trichomeless and triterpene-free poplar mutants.     

Development of Commercially Acceptable Formulations of the Nematophagous FungusVerticillium chlamydosporium

Studies in shaken flasks and a 20-liter bioreactor showed that biomass ofVerticillium chlamydosporiumcould be produced in large quantities in liquid culture. The fungus grew readily in media containing commercially available, low-cost ingredients (e.g., cotton seed meal, soybean meal) and a volumetric productivity of about 0.3 g/h/liter was achieved in the bioreactor. Chlamydospores were not produced in submerged culture, the biomass consisting only of mycelia and conidia. When this biomass was mixed with a carrier (kaolin) and a binder (gum arabic) and the ingredients were granulated and then dried to a moisture content of less than 2%, a biologically active product suitable for application to soil was produced. The fungus grew vigorously from these granules when they were placed on agar and retained its viability when granules were stored in vacuum-sealed bags at 25°C for 12 months. Experiments on tomato in the glasshouse showed that when the formulated product was incorporated into field soil at 10 g granules/liter soil, population densities ofV. chlamydosporiumwere increased to about 10⁴colony-forming units/g soil after 7–14 weeks. Between 37 and 82% of the first generation egg masses produced byMeloidogyne javanicacontained parasitized eggs.