Use of enzymatic methods for rapid enumeration of coliforms in freshwaters

Rapid enumeration methods based on the enzymatic hydrolysis of 4-methylumbelliferyl-beta-D-galactoside and 4-methylumbelliferyl-beta-D-glucuronide were optimized for freshwaters. The enzymes beta-D-galactosidase (GALase) and beta-D-glucuronidase (GLUase) were shown to be already induced in freshwaters when tested, respectively, with the inducers isopropyl-beta-D-thiogalactopyranoside and methyl-beta-D-glucuronide. Both enzymatic activities were compared, respectively, with plate counts of total and faecal coliforms in freshwaters. Enzymatic methods and reference plate counts were significantly correlated in log-log plots. Moreover, the GLUase method allowed the detection of viable (presenting a detectable GLUase activity) but nonculturable Escherichia coli.     

A population genetic analysis of migration: the case of the noctule bat (Nyctalus noctula)

Although rarely assessed, the population genetics of hibernating colonies can help to understand some aspects of population structure, even when samples from nursery or mating colonies are not available, or in studies of migration when both types of samples are available and can be compared. Here we illustrate both points in a survey of mitochondrial DNA (mtDNA) control region sequences used to study the population genetics of hibernating colonies of a migrating species, the noctule bat (Nyctalus noctula). Lacking samples from Scandinavian nursery colonies, we use a North European hibernacula to suggest that Scandinavian populations are isolated from Central and East European colonies. Then, we compare genetic diversities of nursery and hibernating colonies. We find a significantly higher haplotype diversity in hibernacula, confirming that they consist of individuals from different nursery colonies. Finally, we show that pairwise comparisons of the haplotype frequencies of nursery and hibernating colonies contain some information on the migration direction of the noctule bat.     

An interlaboratory comparison of physiological and genetic properties of four Saccharomyces cerevisiae strains

To select a Saccharomyces cerevisiae reference strain amenable to experimental techniques used in (molecular) genetic, physiological and biochemical engineering research, a variety of properties were studied in four diploid, prototrophic laboratory strains. The following parameters were investigated: 1) maximum specific growth rate in shake-flask cultures; 2) biomass yields on glucose during growth on defined media in batch cultures and steady-state chemostat cultures under controlled conditions with respect to pH and dissolved oxygen concentration; 3) the critical specific growth rate above which aerobic fermentation becomes apparent in glucose-limited accelerostat cultures; 4) sporulation and mating efficiency; and 5) transformation efficiency via the lithium-acetate, bicine, and electroporation methods. On the basis of physiological as well as genetic properties, strains from the CEN.PK family were selected as a platform for cell-factory research on the stoichiometry and kinetics of growth and product formation.     

Treatment of separation anxiety in dogs with clomipramine: results from a prospective, randomized, double-blind, placebo-controlled, parallel-group, multicenter clinical trial

The efficacy and tolerability of clomipramine in the treatment of separation anxiety in dogs was tested in a prospective, randomized, double-blind, placebo-controlled, parallel-group, international multicenter clinical trial. For a diagnosis of separation anxiety, dogs had to exhibit at least one of the following signs in the absence of their owner: destruction, defecation, urination and/or vocalization, as well as the behaviour suggestive of "hyper-attachment" to their owner. A total of 95 dogs were randomized to receive one of the three treatments for 2-3 months: "standard-dose" clomipramine (1 to <2 mg/kg, PO, q. 12 h); "low-dose" clomipramine (0.5 to <1 mg/kg, PO, q. 12 h); and placebo (PO, q. 12 h). All dogs received behavioural therapy. Dogs were examined at four time points (days 0, 28, 56 and 84) after the initiation of therapy. Improvement in each dog's behaviour at days 28, 56 and 84 was evaluated in comparison to its behaviour at day 0.The results showed that, compared to placebo, dogs receiving standard-dose clomipramine were rated improved at least three times faster for the signs destruction, defecation and urination. At most time points, more dogs in the standard-dose clomipramine group were rated improved for the signs destruction, defecation and urination, and in an owner's global assessment of the dog's overall behaviour (p<0.05 at certain time points). However, there were no statistically significant differences at any time point between the standard dose and the placebo groups in the sign vocalization. The low-dose clomipramine group produced no statistically significant effect when compared with placebo. Mild and transient vomiting was noted as a side effect of clomipramine in a small number of dogs.It is concluded that addition of standard-dose (1 to <2 mg/kg, PO, q. 12 h) clomipramine to conventional behavioural therapy for 2-3 months ameliorated the signs of separation anxiety in dogs.     

Granule-bound starch synthase: structure, function, and phylogenetic utility

Interest in the use of low-copy nuclear genes for phylogenetic analyses of plants has grown rapidly, because highly repetitive genes such as those commonly used are limited in number. Furthermore, because low- copy genes are subject to different evolutionary processes than are plastid genes or highly repetitive nuclear markers, they provide a valuable source of independent phylogenetic evidence. The gene for granule-bound starch synthase (GBSSI or waxy) exists in a single copy in nearly all plants examined so far. Our study of GBSSI had three parts: (1) Amino acid sequences were compared across a broad taxonomic range, including grasses, four dicotyledons, and the microbial homologs of GBSSI. Inferred structural information was used to aid in the alignment of these very divergent sequences. The informed alignments highlight amino acids that are conserved across all sequences, and demonstrate that structural motifs can be highly conserved in spite of marked divergence in amino acid sequence. (2) Maximum-likelihood (ML) analyses were used to examine exon sequence evolution throughout grasses. Differences in probabilities among substitution types and marked among-site rate variation contributed to the observed pattern of variation. Of the parameters examined in our set of likelihood models, the inclusion of among-site rate variation following a gamma distribution caused the greatest improvement in likelihood score. (3) We performed cladistic parsimony analyses of GBSSI sequences throughout grasses, within tribes, and within genera to examine the phylogenetic utility of the gene. Introns provide useful information among very closely related species, but quickly become difficult to align among more divergent taxa. Exons are variable enough to provide extensive resolution within the family, but with low bootstrap support. The combined results of amino acid sequence comparisons, maximum-likelihood analyses, and phylogenetic studies underscore factors that might affect phylogenetic reconstruction. In this case, accommodation of the variable rate of evolution among sites might be the first step in maximizing the phylogenetic utility of GBSSI.      

The effects of dietary astaxanthin on the carotenoid pattern of the prawn Penaeus japonicus during postlarval development

Penaeus japonicus postlarvae, reared under laboratory conditions, were fed an astaxanthin enriched diet to the investigate carotenoid metabolic capabilities during the postlarval development. Animals fed astaxanthin were found to absorb this carotenoid. The decrease of pigment concentration in the carotenoid starved group is related to the duration of the experimental feeding conditions; the carotenoid depletion depends upon the postlarval status at the starting point. As has been shown for adult prawns, the carotenoid pattern of postlarval stages, regardless of the diet, consists mainly of free and esterified astaxanthin; the relative amounts of these fractions undergo slight variations depending on the diet.     

Vegetation of tuscan ultramafic soils in relation to edaphic and physical factors

Vegetation and soil sampling were carried out in 80 plots located in five different ultramafic (serpentine) sites of Tuscany, central Italy. The physical and chemical features of each plot were determined and the species composition and cover recorded. The exchangeable fraction of soil metals was analysed because it gives a measure of their concentrations available to plants. The plots were classified by cluster analysis and ANOVA was used to compare the environmental variables of the groups of plots. Canonical correspondence analysis was used to detect the principal factors for gradients of species composition within the plant communities. A higher content of exchangeable metals was found under the more evolved and structured plant communities, suggesting that serpentine vegetation of Tuscany is not strongly limited by soil metals, such as chromium, cobalt, nickel and magnesium, typically associated with ultramafic soils. The low nutrient content of the soils and drought stress mainly due to topographical features, appear to have a more significant role in determining the typical scattered vegetation of the Tuscan ultramafics.     

The diabetic rat kidney mediates inosituria and selective urinary partitioning of D-chiro-inositol

Diabetic nephropathy is a serious complication of diabetes mellitus with a pressing need for effective metabolic markers to detect renal impairment. Of potential significance are the inositol compounds, myo-inositol (MI), and the less abundant stereoisomer, D-chiro-inositol (DCI), which are excreted at increased levels in the urine in diabetes mellitus, a phenomenon known as inosituria. There is also a selective urinary excretion of DCI compared to MI. As the biological origins of altered inositol metabolism in diabetes mellitus are unknown, the aim of this study was to determine whether the diabetic kidney was directly responsible. Kidneys isolated from four-week streptozotocin-induced diabetic rats were characterized by a 3-fold reduction in glomerular filtration rate (GFR) compared to matched non-diabetic kidneys. When perfused with fixed quantities of MI (50 µM) and DCI (5 µM) under normoglycemic conditions (5 mM glucose), GFR-normalized urinary excretion of MI was increased by 1.7-fold in diabetic vs. non-diabetic kidneys. By comparison, GFR-normalized urinary excretion of DCI was increased by 4-fold. Perfusion conditions replicating hyperglycemia (20 mM glucose) potentiated DCI but not MI urinary excretion in both non-diabetic and diabetic kidneys. Overall, there was a 2.4-fold increase in DCI urinary excretion compared to MI in diabetic kidneys that was independent of glucose ambience. This increased urinary excretion of DCI and MI in diabetic kidneys occurred despite increased renal expression of the inositol transporters, sodium myo-inositol transporter subtype 1 and 2 (SMIT1 and SMIT2). These findings show that the diabetic kidney primarily mediates inosituria and altered urinary partitioning of MI and DCI. Urinary inositol levels might therefore serve as an indicator of impaired renal function in diabetes mellitus with wider implications for monitoring chronic kidney disease.     

Evidence of facultative daytime hypothermia in a small passerine wintering at northern latitudes

The use of hypothermia as a means to save energy is well documented in birds. This energy‐saving strategy is widely considered to occur exclusively at night in diurnally active species. However, recent studies suggest that facultative hypothermia may also occur during the day. Here, we document the use of daytime hypothermia in foraging Black‐capped Chickadees Poecile atricapillus wintering in eastern Canada. We measured the body temperature (T_b) of 126 individuals (plus 48 repeated measures) during a single winter and related values to ambient temperature (T_a) at the time of capture. We also tested whether daytime hypothermia was correlated with the size of body reserves (residuals of mass on structural size and fat score) and levels of metabolic performance (basal metabolic rate and maximum thermogenic capacity). We found that T_b of individual birds was lower when captured at low T_a, reaching values as low as 35.5 °C in actively foraging individuals. T_b was unrelated to metabolic performance or measures of body reserves. Therefore, daytime hypothermia does not result from individuals being unable to maintain T_b during cold spells or to a lack of body reserves. Our data also demonstrated a high level of individual variation in the depth of hypothermia, the causes of which remain to be explored.     

Optimal whole-body vibration settings for muscle strength and power enhancement in human knee extensors

This study compared the effects of 6-week whole-body vibration (WBV) training programs with different frequency and peak-to-peak displacement settings on knee extensor muscle strength and power. The underlying mechanisms of the expected gains were also investigated. Thirty-two physically active male subjects were randomly assigned to a high-frequency/high peak-to-peak displacement group (HH; n = 12), a low-frequency/low peak-to-peak displacement group (LL; n = 10) or a sham training group (SHAM; n = 10). Maximal voluntary isometric, concentric and eccentric torque of the knee extensors, maximal voluntary isometric torque of the knee flexors, jump performance, voluntary muscle activation, and contractile properties of the knee extensors were assessed before and after the training period. Significant improvement in knee extensor eccentric voluntary torque (P < 0.01), knee flexor isometric voluntary torque (P < 0.05), and jump performance (P < 0.05) was observed only for HH group. Regardless of the group, knee extensor muscle contractile properties (P < 0.05) were enhanced. No modification was observed for voluntary muscle activation or electrical activity of agonist and antagonist muscles. We concluded that high-frequency/high peak-to-peak displacement was the most effective vibration setting to enhance knee extensor muscle strength and jump performance during a 6-week WBV training program and that these improvements were not mediated by central neural adaptations.