Stimulation of bioprocesses by ultrasound

Ultrasound (US) has become a ubiquitous technological process in a large variety of scientific disciplines. However, little information exists on the use of ultrasound to enhance biological processes and/or processing and consequently this paper provides an overview of work reported to date on this topic. This review provides a brief introduction to ultrasound and the history of ultrasound as applied to bioprocesses. This is followed by a discussion of the influence of US on discrete enzyme systems, enzymes used in bioremediation, microbial fermentations and enzymatic hydrolysis of biopolymers. Augmentation of anaerobic digestion by US is then considered along with enhancement of enzymes in food science and technology. The use of ultrasonically stimulated enzymes in synthesis is then considered and other relevant miscellaneous topics are described. It is concluded that the precise mechanism of action of US in bio-processing remains to be elucidated though a variety of plausible suggestions are made

Autophagy as a promoter of longevity: insights from model organisms.

Autophagy is a conserved process that catabolizes intracellular components to maintain energy homeostasis and to protect cells against stress. Autophagy has crucial roles during development and disease, and evidence accumulated over the past decade indicates that autophagy also has a direct role in modulating ageing. In particular, elegant studies using yeasts, worms, flies and mice have demonstrated a broad requirement for autophagy-related genes in the lifespan extension observed in a number of conserved longevity paradigms. Moreover, several new and interesting concepts relevant to autophagy and its role in modulating longevity have emerged. First, select tissues may require or benefit from autophagy activation in longevity paradigms, as tissue-specific overexpression of single autophagy genes is sufficient to extend lifespan. Second, selective types of autophagy may be crucial for longevity by specifically targeting dysfunctional cellular components and preventing their accumulation. And third, autophagy can influence organismal health and ageing even non-cell autonomously, and thus, autophagy stimulation in select tissues can have beneficial, systemic effects on lifespan. Understanding these mechanisms will be important for the development of approaches to improve human healthspan that are based on the modulation of autophagy

Whale Safe Gillnets

A grant from the Virginia Sea Grant program to test some modified gillnets to find ways of fishing that would allow whales to break free from our fishing gear

Spin dynamics of coupled spin ladders near quantum criticality in Ba2CuTeO6

We report inelastic neutron scattering measurements of the magnetic excitations in Ba2CuTeO6, proposed by ab initio calculations to magnetically realize weakly coupled antiferromagnetic two-leg spin-1/2 ladders. Isolated ladders are expected to have a singlet ground state protected by a spin gap. Ba2CuTeO6 orders magnetically, but with a small Neel temperature relative to the exchange strength, suggesting that the interladder couplings are relatively small and only just able to stabilize magnetic order, placing Ba2CuTeO6 close in parameter space to the critical point separating the gapped phase and Neel order. Through comparison of the observed spin dynamics with linear spin wave theory and quantum Monte Carlo calculations, we propose values for all relevant intra- and interladder exchange parameters, which place the system on the ordered side of the phase diagram in proximity to the critical point. We also compare high field magnetization data with quantum Monte Carlo predictions for the proposed model of coupled ladders.Comment: 14 pages, 12 figure

Genotypic analysis of receptor-like protein kinases with leucine-rich repeat motifs

Abstract only availableReceptor-like protein kinases (RLKs) are transmembrane proteins that transmit extracellular signals across a membrane with the use of an intracellular kinase domain. RLKs play important roles in plant growth and development, plant-microbe interactions, and defense responses. In Arabidopsis thaliana, a commonly used genetic model system for plants, 417 genes encode RLKs. Though plant RLKs have a monophyletic origin and belong to a clade that also contains the animal Pelle cytoplasmic kinases, they can be divided into distinct families based on their extracellular motifs. The most common extracellular motif in plant RLKs are the leucine-rich repeat that are thought to be involved in protein-protein interactions. Over half of RLKS found in Arabidopsis thaliana have leucine-rich repeat extracellular motifs. As a genetic model, the genome of Arabidopsis has been fully sequenced; however, the functions of many genes are still unknown. To uncover their function, experiments are being done using the principles of reverse genetics. By inserting T-DNA segments into the genome, the function of a gene can be disrupted. The T-DNA insertion into a gene would prevent a functional protein from being produced. Without the production of this protein, a specific mutant phenotype is likely to result. However, duplication of genes with similar sequences and therefore, possibly similar functions, may hinder the production of a mutant phenotype. As such, all the genes must also be rendered functionless. Our experiment consisted of creating functional knock-outs for genes found in families XIe, XIh, XIg, and XId. Single and double mutants were then genotyped to see if any heterozygous or homozygous progeny had been produced and had survived. Sequencing of the flanking regions of the t-DNA insert was also completed. Twelve of thirteen genes yielded single mutant homozygotes. Of the six double mutant crosses genotyped, all yielded heterozygotes. Crosses were then made between homozygotes of one line of a particular gene with those from another line of a different, but related gene. Results for function and phenotype are pending.NSF-REU Biology & Biochemistr

Respiration of aged soil carbon during fall in permafrost peatlands enhanced by active layer deepening following wildfire but limited following thermokarst

Permafrost peatlands store globally significant amounts of soil organic carbon (SOC) that may be vulnerable to climate change. Permafrost thaw exposes deeper, older SOC to microbial activity, but SOC vulnerability to mineralization and release as carbon dioxide is likely influenced by the soil environmental conditions that follow thaw. Permafrost thaw in peat plateaus, the dominant type of permafrost peatlands in North America, occurs both through deepening of the active layer and through thermokarst. Active layer deepening exposes aged SOC to predominately oxic conditions, while thermokarst is associated with complete permafrost thaw which leads to ground subsidence, inundation and soil anoxic conditions. Thermokarst often follows active layer deepening, and wildfire is an important trigger of this sequence. We compared the mineralization rate of aged SOC at an intact peat plateau (∼70 cm oxic active layer), a burned peat plateau (∼120 cm oxic active layer), and a thermokarst bog (∼550 cm anoxic peat profile) by measuring respired 14C-CO2. Measurements were done in fall when surface temperatures were near-freezing while deeper soil temperatures were still close to their seasonal maxima. Aged SOC (1600 yrs BP) contributed 22.1 ± 11.3% and 3.5 ± 3.1% to soil respiration in the burned and intact peat plateau, respectively, indicating a fivefold higher rate of aged SOC mineralization in the burned than intact peat plateau (0.15 ± 0.07 versus 0.03 ± 0.03 g CO2-C m−2 d−1). None or minimal contribution of aged SOC to soil respiration was detected within the thermokarst bog, regardless of whether thaw had occurred decades or centuries ago. While more data from other sites and seasons are required, our study provides strong evidence of substantially increased respiration of aged SOC from burned peat plateaus with deepened active layer, while also suggesting inhibition of aged SOC respiration under anoxic conditions in thermokarst bogs