Effective lipid lowering diets including lean meat

The plasma lipid and lipoprotein responses to two modified isoenergetic diets including meat were studied in 15 free living men with hyperlipidaemia (mean plasma cholesterol and triglyceride concentrations 8·1 and 3·4 mmol/l). A reference diet (diet A, 42% energy from fat, ratio of polyunsaturated to saturated fatty acids (P:S ratio) 0·2) was compared with a fat reduced diet (diet B, 35% energy from fat, P:S ratio 0·5) and with a further fat modified diet supplemented with fibre (diet C, 27% energy from fat, P:S ratio 1·0). Daily intake of meat and meat products (180 g/day) was the same in each dietary period; that in diet A had a fat content typical of the average British diet, whereas that in diets B and C was based on very lean meat and meat products. During consumption of diet B the plasma cholesterol concentration fell by 8·6% and low density lipoprotein cholesterol by 11%. During consumption of diet C plasma cholesterol fell by 18·5% and low density lipoprotein cholesterol by 23·8%. Triglyceride and high density lipoprotein cholesterol concentrations and body weight did not change appreciably during the study.A modified diet including a moderate amount of lean meat and meat products is compatible with a reduced lipoprotein mediated risk of atherosclerotic heart disease.     

The effect of organic matter on sedimentary phosphorus release in an Australian reservoir

Australian reservoirs, compared to much of the world, are subjected to extreme arid and semi-arid climatic conditions where dam volumes can range from near-empty to full, often with rapid filling events. P-release, after re-flooding of desiccated sediments, can be important to water quality, and can be further influenced by dried macrophyte, exposed as water recedes and incorporated into sediments. P-release from Lake Rowlands (New South Wales, Australia) sediments was studied under different aerobic and sterile conditions with five carbon source amendments to the sediment (the macrophyte Isoetes sp. in different stages of senescence and acetate). Sedimentary P-release involved a complex array of factors modified by aerobic, biotic and abiotic processes, organic matter breakdown, iron content of sediments and turbulence. Under aerobic conditions, P-release from sterile non-amended sediments and sterile macrophyte-amended sediments was greater than from non-sterile sediments. Under anaerobic conditions, P-release was maximal from non-sterile macrophyte-amended sediments, probably via pathways involving fermentative Fe³⁺-reducing bacteria where electrons are transferred from organic matter to amorphous Fe(OOH) leading to Fe²⁺ and consequent release of P. Macrophyte addition (whether fresh or dried) enhanced P-release under anaerobic compared with aerobic conditions. P-release from acetate-amended sediments appeared to involve acetate aerobes. The re-flooding of sediments, therefore, has the potential to create conditions that are conducive to aerobic sedimentary P-release and should be taken into account in management strategies adopted for reservoirs where levels are likely to fluctuate.     

Tpz1TPP1 SUMOylation reveals evolutionary conservation of SUMO‐dependent Stn1 telomere association

Elongation of the telomeric overhang by telomerase is counteracted by synthesis of the complementary strand by the CST complex, CTC1(Cdc13)/Stn1/Ten1. Interaction of budding yeast Stn1 with overhang‐binding Cdc13 is increased by Cdc13 SUMOylation. Human and fission yeast CST instead interact with overhang‐binding TPP1/POT1. We show that the fission yeast TPP1 ortholog, Tpz1, is SUMOylated. Tpz1 SUMOylation restricts telomere elongation and promotes Stn1/Ten1 telomere association, and a SUMO‐Tpz1 fusion protein has increased affinity for Stn1. Our data suggest that SUMO inhibits telomerase through stimulation of Stn1/Ten1 action by Tpz1, highlighting the evolutionary conservation of the regulation of CST function by SUMOylation.     

Proteomic analysis of Drosophila mojavensis male accessory glands suggests novel classes of seminal fluid proteins

Fruit-flies of the genus Drosophila are characterized by overwhelming variation in fertilization traits such as copulatory plug formation, sperm storage organ use, and nutritional ejaculatory donation. Despite extensive research on the genetic model Drosophila melanogaster, little is known about the molecular underpinnings of these interspecific differences. This study employs a proteomic approach to pin-point candidate seminal fluid proteins in Drosophila mojavensis, a cactophilic fruit-fly that exhibits divergent reproductive biology when compared to D. melanogaster. We identify several classes of candidate seminal fluid proteins not previously documented in the D. melanogaster male ejaculate, including metabolic enzymes, nutrient transport proteins, and clotting factors. Conversely, we also define 29 SFPs that are conserved despite >40 million years of Drosophila evolution. We discuss our results in terms of universal processes in insect reproduction, as well as the specialized reproductive biology of D. mojavensis.     

Leaf extraction and analysis framework graphical user interface: segmenting and analyzing the structure of leaf veins and areoles

Interest in the structure and function of physical biological networks has spurred the development of a number of theoretical models that predict optimal network structures across a broad array of taxonomic groups, from mammals to plants. In many cases, direct tests of predicted network structure are impossible given the lack of suitable empirical methods to quantify physical network geometry with sufficient scope and resolution. There is a long history of empirical methods to quantify the network structure of plants, from roots, to xylem networks in shoots and within leaves. However, with few exceptions, current methods emphasize the analysis of portions of, rather than entire networks. Here, we introduce the Leaf Extraction and Analysis Framework Graphical User Interface (LEAF GUI), a user-assisted software tool that facilitates improved empirical understanding of leaf network structure. LEAF GUI takes images of leaves where veins have been enhanced relative to the background, and following a series of interactive thresholding and cleaning steps, returns a suite of statistics and information on the structure of leaf venation networks and areoles. Metrics include the dimensions, position, and connectivity of all network veins, and the dimensions, shape, and position of the areoles they surround. Available for free download, the LEAF GUI software promises to facilitate improved understanding of the adaptive and ecological significance of leaf vein network structure.     

Discovering robust protein biomarkers for disease from relative expression reversals in 2-D DIGE data

This study assesses the ability of a novel family of machine learning algorithms to identify changes in relative protein expression levels, measured using 2-D DIGE data, which support accurate class prediction. The analysis was done using a training set of 36 total cellular lysates comprised of six normal and three cancer biological replicates (the remaining are technical replicates) and a validation set of four normal and two cancer samples. Protein samples were separated by 2-D DIGE and expression was quantified using DeCyder-2D Differential Analysis Software. The relative expression reversal (RER) classifier correctly classified 9/9 training biological samples (p<0.022) as estimated using a modified version of leave one out cross validation and 6/6 validation samples. The classification rule involved comparison of expression levels for a single pair of protein spots, tropomyosin isoforms and alpha-enolase, both of which have prior association as potential biomarkers in cancer. The data was also analyzed using algorithms similar to those found in the extended data analysis package of DeCyder software. We propose that by accounting for sources of within- and between-gel variation, RER classifiers applied to 2-D DIGE data provide a useful approach for identifying biomarkers that discriminate among protein samples of interest.     

Metabolism of halogenated bisphosphonates by the cellular slime mould Dictyostelium discoideum.

Methylenebisphosphonate and its monofluoro-, difluoro- and dichloro- derivatives inhibited growth of amoebae of Dictyostelium discoideum. Dichloromethylenebisphosphonate was the most potent inhibitor of amoebal growth whereas difluoromethylenebisphosphonate was the least potent inhibitor. Each of the bisphosphonates was taken up by the amoebae and incorporated into the corresponding beta, gamma-methylene analogue of adenosine triphosphate. Two of the bisphosphonates were also incorporated into the corresponding analogues of diadenosyl tetraphosphate. No correlation was found between the ability of the bisphosphonates to inhibit amoebal growth and the extent to which they were metabolised.     

The mechanism of voltage-sensitive dye responses on sarcoplasmic reticulum

Summary The mechanism of voltage-sensitive dye responses was analyzed on sarcoplasmic reticulum vesicles to assess the changes in membrane potential related to Ca²⁺ transport. The absorbance and fluorescence responses of 3,3-diethyl-2,2-thiadicarbocyanine, 3,3-dimethyl-2,2-indodicarbocyanine and oxonol VI during ATP-dependent Ca²⁺ transport are influenced by the effect of accumulated Ca²⁺ upon the surface potential of the vesicle membrane. These observations place definite limitations on the use of these probes as indicators of ion-diffusion potential in processes which involve large fluctuations in free Ca²⁺ concentrations. Nile Blue A appeared to produce the cleanest optical signal to negative transmembrane potential, with least direct interference from Ca²⁺, encouraging the use of Nile Blue A for measurement of the membrane potential of sarcoplasmic reticulumin vivo andin vitro. 1,3-dibutylbarbituric acid (5)-1-(p-sulfophenyl)-3 methyl, 5-pyrazolone pentamethinoxonol (WW 781) gave no optical response during ATP-induced Ca²⁺ transport and responded primarily to changes in surface potential on the same side of the membrane where the dye was applied. Binding of these probes to the membrane plays a major role in the optical response to potential, and changes in surface potential influence the optical response by regulating the amount of membrane-bound dye. The observations are consistent with the electrogenic nature of ATP-dependent Ca²⁺ transport and indicate the generation of about 10 mV inside-positive membrane potential during the initial phase of Ca²⁺ translocation. The potential generated during Ca²⁺ transport is rapidly dissipated by passive ion fluxes across the membrane.     

Circadian Modulation of Cold-Induced Thermogenesis in the Golden Hamster

The relationship between the circadian and homeostatic control of body temperature was studied in golden hamsters maintained under a 14:10 LD cycle. Telemetric records of body temperature showed that body temperature oscillates daily with a low phase during the light section of the LD cycle and a high phase during the dark section. The low phase of the temperature rhythm was found to start two hours after lights on and to last about 8 hours. The high phase was found to start immediately after lights off and to last about 8 hours also. Metabolic heat production was measured by indirect calorimetry during the high phase and the low phase of the body temperature rhythm. Heat production in a thermoneutral environment was higher during the high phase of the body temperature rhythm than during the low phase, but cold-induced thermogenesis was greater during the low phase than during the high phase. This finding suggests that the autonomic thermoregulatory system is more responsive to cold stress during the low phase than during the high phase. Consequently, the daily oscillation of body temperature cannot be explained by an elevation of the thermoregulatory set point during the high phase of the rhythm. The homeostatic and circadian control of body temperature seem to be exerted separately from each other.