Use of low nutrient enrichments to access novel amylase genes in silent diversity of thermophiles

By combining low nutrient enrichments and molecular methods, a high diversity of new amylase genes was detected in a neutral sulphide-rich hot spring in Iceland. Enrichments based on hot spring water and low concentrations of starch were used to select slow-growing, starch-degrading microorganisms. Six enrichments had in total 17 bacterial types detected by 16S rRNA analysis, mostly related to the Thermus-Deinococcus group, green non-sulphur bacteria, gram positives, and uncultivated new candidate divisions. No Archaea were found. The apparent 16S rRNA species composition of the enrichments was very different from that of the microbial mat in the same hot spring. DNA samples obtained from 4 enrichments and from hot spring biomass were screened by PCR for amylase genes in glycoside-hydrolase family 13. Degenerate primers, based on conserved amino acid sequences from multiplealignments of family 13, enabled the detection of 18 amylase sequence types in the enrichments, including -amylases, -glucosidases, 1,4--glucan branching enzymes, cyclomaltodextrin hydrolases, maltogenic amylases and neopullulanases, and unspecified family 13 glycoside-hydrolases. Only one unique neopullulanase sequence, also found in most of the enrichments, was detected in the hot spring biomass DNA. The results suggest that the enrichment method combined with sequence-based screening is an efficient way to access the silent, i.e. not detectable, gene diversity in natural environments.     

Cooling vest worn during active warm-up improves 5-km run performance in the heat.

We investigated whether a cooling vest worn during an active warm-up enhances 5-km run time in the heat. Seventeen competitive runners (9 men, maximal oxygen uptake = 66.7 +/- 5.9 ml x kg(-1) x min(-1); 8 women, maximal oxygen uptake = 58.0 +/- 3.2 ml x kg(-1) x min(-1)) completed two simulated 5-km runs on a treadmill after a 38-min active warm-up during which they wore either a T-shirt (C) or a vest filled with ice (V) in a hot, humid environment (32 degrees C, 50% relative humidity). Wearing the cooling vest during warm-up significantly (P < 0.05) blunted increases in body temperature, heart rate (HR), and perception of thermal discomfort during warm-up compared with control. At the start of the 5-km run, esophageal, rectal, mean skin, and mean body temperatures averaged 0.3, 0.2, 1.8, and 0.4 degrees C lower; HR averaged 11 beats/min lower; and perception of thermal discomfort (5-point scale) averaged 0.6 point lower in V than C. Most of these differences were eliminated during the first 3.2 km of the run, and these variables were not different at the end. The 5-km run time was significantly lower (P < 0.05) by 13 s in V than C, with a faster pace most evident during the last two-thirds of the run. We conclude that a cooling vest worn during active warm-up by track athletes enhances 5-km run performance in the heat. Reduced thermal and cardiovascular strain and perception of thermal discomfort in the early portion of the run appear to permit a faster pace later in the run.     

Relation of heart rate to percent VO2 peak during submaximal exercise in the heat.

We tested the hypothesis that elevation in heart rate (HR) during submaximal exercise in the heat is related, in part, to increased percentage of maximal O(2) uptake (%Vo(2 max)) utilized due to reduced maximal O(2) uptake (Vo(2 max)) measured after exercise under the same thermal conditions. Peak O(2) uptake (Vo(2 peak)), O(2) uptake, and HR during submaximal exercise were measured in 22 male and female runners under four environmental conditions designed to manipulate HR during submaximal exercise and Vo(2 peak). The conditions involved walking for 20 min at approximately 33% of control Vo(2 max) in 25, 35, 40, and 45 degrees C followed immediately by measurement of Vo(2 peak) in the same thermal environment. Vo(2 peak) decreased progressively (3.77 +/- 0.19, 3.61 +/- 0.18, 3.44 +/- 0.17, and 3.13 +/- 0.16 l/min) and HR at the end of the submaximal exercise increased progressively (107 +/- 2, 112 +/- 2, 120 +/- 2, and 137 +/- 2 beats/min) with increasing ambient temperature (T(a)). HR and %Vo(2 peak) increased in an identical fashion with increasing T(a). We conclude that elevation in HR during submaximal exercise in the heat is related, in part, to the increase in %Vo(2 peak) utilized, which is caused by reduced Vo(2 peak) measured during exercise in the heat. At high T(a), the dissociation of HR from %Vo(2 peak) measured after sustained submaximal exercise is less than if Vo(2 max) is assumed to be unchanged during exercise in the heat.     

Nutrient scavenging activity and antagonistic factors of non-photobiont lichen-associated bacteria: a review

Lichens are defined as the specific symbiotic structure comprising a fungus and a green alga and/or cyanobacterium. Up until recently, non-photobiont endothallic bacteria, while known to be present in large numbers, have generally been dismissed as functionally irrelevant cohabitants of the lichen thallus, or even environmental contaminants. Recent analyses of lichen metagenomes and innovative co-culture experiments have uncovered a functionally complex community that appears to contribute to a healthy lichen thallus in several ways. Lichen-associated bacteriomes are typically dominated by several lineages of Proteobacteria, some of which may be specific for lichen species. Recent work has implicated members of these lineages in several important ecophysiological roles. These include nutrient scavenging, including mobilization of iron and phosphate, nitrogen fixation, cellulase, xylanase and amylase activities, and oxidation of recalcitrant compounds, e.g. aromatics and aliphatics. Production of volatile organic compounds, conferring antibacterial and antifungal activity, has also been demonstrated for several lichen-associated isolates. In the present paper we review the nature of non-phototrophic endolichenic bacteria associated with lichens, and give insight into the current state of knowledge on their importance the lichen symbiotic association.     

Increased levels of cell-free hemoglobin,oxidation markers,and the antioxidative heme scavenger α1-microglobulin in preeclampsia

Preeclampsia is a major cause of morbidity and mortality during pregnancy. To date, the pathogenesis of the disease is not fully understood. Recent studies show that preeclampsia is associated with overexpression of the hemoglobin genes α2 and γ and accumulation of the protein in the vascular lumen of the placenta. Hypothesizing that cell-free hemoglobin leaks from the placenta into the maternal circulation and contributes to the endothelial damage and symptoms by inducing oxidative stress, we analyzed fetal and adult hemoglobin (HbF, HbA), haptoglobin, oxidation markers, and the heme scavenger and antioxidant α₁-microglobulin in plasma, urine, and placenta in preeclamptic women (n = 28) and women with normal pregnancy (n = 27). The mean plasma concentrations of HbF, HbA, protein carbonyl groups, membrane peroxidation capacity, and α₁-microglobulin were significantly increased in preeclamptic women. The levels of total plasma Hb correlated strongly with the systolic blood pressure. The plasma haptoglobin concentrations of women with preeclampsia were significantly depressed. Increased amounts of α₁-microglobulin mRNA and protein were found in placenta from preeclamptic women, and the levels of plasma and placenta α₁-microglobulin correlated with the plasma Hb concentrations. The heme-degrading form t-α₁-microglobulin was significantly increased in urine in preeclampsia. These results support the idea that hemoglobin-induced oxidative stress is a pathogenic factor in preeclampsia.     

Development and Validation of Arc Nanobodies: New Tools for Probing Arc Dynamics and Function

Neurochemical Research - Activity-regulated cytoskeleton-associated (Arc) protein plays key roles in long-term synaptic plasticity, memory, and cognitive flexibility. However, an integral...     

In vitro analysis of expression vectors for DNA vaccination of horses: the effect of a Kozak sequence

One of the prerequisite for developing DNA vaccines for horses are vectors that are efficiently expressed in horse cells.     

Effect of resistance exercise on postprandial lipemia.

The purpose of this study was to examine the effect of resistance exercise on postprandial lipemia. Fourteen young men and women participated in each of three treatments: 1) control (Con), 2) resistance exercise (RE), and 3) aerobic exercise (AE) estimated to have an energy expenditure (EE) equal that for RE. Each trial consisted of performing a treatment on day 1 and ingesting a fat-tolerance test meal 16 h later (day 2). Resting metabolic rate and fat oxidation were measured at baseline and at 3 and 6 h postprandial on day 2. Blood was collected at baseline and at 0.5, 1, 2, 3, 4, 5, and 6 h after meal ingestion. RE and AE were similar in EE [1.7 +/- 0.1 vs. 1.6 +/- 0.1 (SE) MJ, respectively], as measured by using the Cosmed K4b(2). Baseline triglycerides (TG) were significantly lower after RE than after Con (19%) and AE (21%). Furthermore, the area under the postprandial response curve for TG, adjusted for baseline differences, was significantly lower after RE than after Con (14%) and AE (18%). Resting fat oxidation was significantly greater after RE than after Con (21%) and AE (28%). These results indicate that resistance exercise lowers baseline and postprandial TG, and increases resting fat oxidation, 16 h after exercise.