Tracking predation of subterranean pests: digestion of corn rootworm DNA by a generalist mite

qPCR is a useful tool for understanding predator–prey relationships. We investigated rootworm DNA digestion by male and female predatory mites. Males and females initially consumed comparable amounts of DNA, which was digested at similar rates. Field-collected mites need to be preserved quickly for best qPCR results.     

Influence of progestins on serum hormone levels in postmenopausal women with advanced breast cancer--I. General findings

The influence of oral high dose progestin (medroxyprogesterone acetate, MPA and megestrol acetate, MA) treatment on serum hormone levels was studied in ten postmenopausal women with advanced breast cancer. The gonadotropins and ACTH were significantly reduced by greater than 50 and 23%, respectively. Serum cortisol, DHEAS, androstenedione and testosterone were all significantly reduced (mean reduction between 64 and 76%), while serum estrone, estradiol and estrone sulfate were significantly reduced by 20-30%. Sex hormone binding globulin (SHBG) and corticosteroid binding globulin (CGB) were reduced by 68 and 25%, respectively. Although the dose of MA used (160 mg/day) was only 1/6 of the MPA dose (1000 mg/day), the mean serum level of MA was 2-fold higher than the mean serum level of MPA. MPA treatment gave a more pronounced suppression of SHBG than MA treatment, while estrone sulfate levels were more suppressed by MA. These findings suggest a differential effect of MPA and MA on certain plasma hormones, possibly of importance for understanding the mechanism of action of the two drugs. The reduction of estrone sulfate may be beneficial for the action of MA against breast cancer.     

Effects of Glucose Concentrations on Cadmium, Copper, Mercury, and Zinc Toxicity to a Klebsiella sp

The influence of glucose concentration on Cd, Cu, Hg, and Zn toxicity to a Klebsiella sp. was studied by following the degradation of ¹⁴C-labeled glucose at pH 6.0. Uptake of ¹⁴C into the cells was also determined. The carbon concentrations ranged from 0.01 to 40 mg liter⁻¹, which are equivalent to soluble C concentrations in natural environments. The toxicity of Cu, Cd, and Zn to a Klebsiella sp. was affected considerably by the C concentration. Copper at 10⁻⁵ M was toxic when the carbon concentration was 10 or 40 mg liter⁻¹, while at 0.01 to 1.0 mg liter⁻¹ no toxicity was observed. Cadmium and zinc were toxic at 10⁻² M in media containing 0.01 to 1.0 mg of C liter⁻¹. At C concentrations greater than 1.0 mg liter⁻¹, the inhibition of glucose degradation and carbon assimilation was observed at 10⁻³ M Cd and Zn. The toxicity of mercury seemed to be independent of the C concentration. Results of this study showed that the nutritional state of an organism may have a profound effect on its sensitivity to metals. Metals taken up by an energy-driven transport system may be less toxic under conditions of C starvation. The C concentration should be taken into account when evaluating results from toxicity studies, especially as most microorganisms in nature live under energy-limited conditions.     

Effect of hypotonic stress on ornithine decarboxylase mRNA expression in cultured cells.

This report examines the effect of hypotonic stress on ornithine decarboxylase (ODC) activity and ODC mRNA concentrations in LLC-PK1 cells. Earle's balanced salts solution minus glucose (EBSS-G) with decreasing concentrations of NaCl was utilized as the ODC induction medium. Hypotonic EBSS-G increased both the concentration of ODC mRNA and the specific activity of ODC in LLC-PK1 cells. Actinomycin D and cycloheximide prevented the increase in enzyme activity resulting from hypotonic stress. Actinomycin D was also a potent inhibitor of ODC mRNA expression resulting from hypotonic stress. Cycloheximide had very little effect on the induction of ODC mRNA in cells incubated in hypotonic EBSS-G. The magnitude of the increase in both ODC mRNA concentrations and enzyme activity was dependent on the incubation time in hypotonic media. The increase in ODC mRNA concentrations preceded the elevation in enzyme activity. ODC mRNA concentrations and the specific activity of ODC increased as a function of decreasing media osmolarity. The addition of putrescine, spermidine, and spermine to EBSS-G containing reduced NaCl suppressed the increase in LLC-PK1 ODC activity related to hypotonic stress. In contrast, these polyamines did not prevent the increase in ODC mRNA resulting from hypotonic shock. Furthermore, it was demonstrated that hypotonic stress increases ODC mRNA levels and enzyme activity in four additional cell lines from two different species. Based on these results it is suggested that one or more signal transducers associated with cell volume expansion enhance expression of the ODC gene.     

Permanent night workers´ sleep and psychosocial factors in hospital work. A comparison to day and shift work

ABSTRACT

We aimed to study whether permanent night workers sleep and psychosocial factors differ from day workers and shift workers. The participants (n = 9 312, 92% females, average age 45 years, most commonly nurses and departmental secretaries) were day workers (DW, n = 2 672), shift workers (SW, n = 6 486) and permanent night workers (PNW, n = 154). The Finnish Public Sector survey responses from six hospital districts from 2012 were combined to payroll data from 91 days preceding the survey. The data were analyzed using Pearson χ²-test, one-way ANOVA and multinomial logistic regression analysis. The PNWs reported slightly longer average sleep length than the SWs or the DWs (7:27 vs. 7:13 and 7:10 h, p < 0.001). The PNWs reported least often difficulties in maintaining sleep (p < 0.001) compared to the SWs and the DWs. The PNWs reported most often difficulties to fall asleep and fatigue during free-time (p-values <0.001). The DWs and PNWs experienced less often work-life conflict than the SWs (25 and 26 vs. 38%, p < 0.001). The PNWs were more often satisfied with autonomy at work and appreciation and fair treatment by colleagues than the DWs or the SWs (p < 0.001). The SWs and PNWs reported remarkably higher occurrence of verbal (p < 0.001, OR 3.71, 95% CI 3.23–4.27 and OR 7.67, 95% CI 5.35–10.99, respectively) and physical workplace violence (p < 0.001, OR 9.24, 95% CI 7.17–11.90 and OR 28.34, 95% CI 16.64–43.06, respectively) compared to DWs. Conclusively, PNWs reported contradictory differences in sleep quality compared to DWs and SWs. PNWs are more often satisfied with their colleagues and autonomy at work than DWs or SWs but face workplace violence remarkably more often.     

New method for toxicity assessment in marine and brackish environments using the macroalga Gracilaria tenuistipitata (Gracilariales,Rhodophyta)

A growth inhibition test method was developed using the macroalga Gracilaria tenuistipitata as the test organism. This alga was chosen because of its high laboratory growth rates, commonly 30–40% d^–1, which are reached in salinities between 5 and 40, and its epiphyte resistance. The toxicity of a number of substances, including heavy metals, herbicides and complex wastewaters towards the alga was assayed. Anti-fouling paints were tested with a modification of the method. EC50 values for heavy metals varied between 0.05 and 17 mg l^–1 and for herbicides between 0.002 and 0.02 mg l^–l. The sensitivity to the toxicant was generally higher at low salinity. Omitting nitrogen and phosphorus additions to the test medium increased the sensitivity and a semi-static performance was possible with maintained or increased sensitivity. Preliminary tests done with a computerised photosynthesis inhibition method produced promising results.In conclusion, this is a simple, sensitive and reproducible test method for assessing the toxicity of substances, wastewaters and anti-fouling paints in brackish and marine environments.     

A connection between pre-mRNA splicing and the cell cycle in fission yeast: cdc28+ is allelic with prp8+ and encodes an RNA-dependent ATPase/helicase.

The fission-yeast gene cdc28+ was originally identified in a screen for temperature-sensitive mutants that exhibit a cell-division cycle arrest and was found to be required for mitosis. We undertook a study of this gene to understand more fully the general requirements for entry into mitosis. Cells carrying the conditional lethal cdc28-P8 mutation divide once and arrest in G2 after being shifted to the restrictive temperature. We cloned the cdc28+ gene by complementation of the temperature-sensitive growth arrest in cdc28-P8. DNA sequence analysis indicated that cdc28+ encodes a member of the DEAH-box family of putative RNA-dependent ATPases or helicases. The Cdc28 protein is most similar to the Prp2, Prp16, and Prp22 proteins from budding yeast, which are required for the splicing of mRNA precursors. Consistent with this similarity, the cdc28-P8 mutant accumulates unspliced precursors at the restrictive temperature. Independently, we isolated a temperature-sensitive pre-mRNA splicing mutant prp8-1 that exhibits a cell-cycle phenotype identical to that of cdc28-P8. We have shown that cdc28 and prp8 are allelic. These results suggest a connection between pre-mRNA splicing and progression through the cell cycle.     

Variation and repeatability of courtship song characters among wild-caught and laboratory-rearedDrosophila montana andD. littoralis males (Diptera: Drosophilidae)

InDrosophila montana andD. littoralis (species of theD. virilis group), females use male courtship song in their mate choice in wild preferring males which produce short and dense sound pulses (Aspi and Hoikkala, 1995). In the present study these song characters were found to be repeatable among overwintered males. Male progenies of wild-caught flies reared in the laboratory, and inD. montana also the males collected in wild before overwintering, exhibited very little variation between males in these characters. Contrary to pulse characters, pulse train characters measured forD. montana song varied significantly between laboratory-reared males. Our findings suggest that inD. montana andD. littoralis song characters playing a part in sexual selection in the wild are more condition dependent than song characters which are not the direct targets of female choice.     

Unveiling of Novel Radiations within Trichodesmium Cluster by hetR Gene Sequence Analysis

The filamentous nonheterocystous cyanobacterial genus Katagnymene is a common diazotrophic component of tropical and subtropical oceans. To assess the phylogenetic affiliation of this taxon, two partial 16S rRNA gene sequences and 25 partial hetR gene sequences originating from the genera Katagnymene and Trichodesmium collected from open, surface waters of the Atlantic, Indian, and Pacific oceans were compared. Single trichomes or colonies were identified morphologically by using light microscopy and then used directly as templates in hetR PCR analyses. In addition, three cultured strains, identified as Katagnymene pelagica, Katagnymene spiralis, and Trichodesmium sp., were examined. The data show that the genus Katagnymene is in the Trichodesmium cluster and that K. pelagica Lemmermann and K. spiralis Lemmermann are most likely one species, despite their different morphologies. Phylogenetic analyses also unveiled four distinct clusters in the Trichodesmium cluster, including one novel cluster. Our findings emphasize the conclusion that known morphological traits used to differentiate marine nonheterocystous cyanobacteria at the genus and species levels correlate poorly with genetic data, and a revision is therefore suggested.     

Quantification of consumption of corn pollen by the predator Coleomegilla maculata (Coleoptera: Coccinellidae) during anthesis in an Illinois cornfield

Abstract 1 Coleomegilla maculata DeGeer feeds on corn pollen in the field, but the degree to which this predator relies on corn pollen as part of its diet is not well understood. We quantified the amount of pollen consumed by C. maculata second, third and fourth instars and adults in the field. 2 Laboratory experiments were conducted to determine the digestion rate and duration of different stadia or stages using temperature regimens that reflected field conditions during anthesis. Coleomegilla maculata larvae and adults were collected from the field and the amount of pollen in their digestive tracts was determined gravimetrically. The rate of digestion, duration of each life stage and the field observations were used to estimate the amount of pollen consumed by second, third and fourth instars and adults. 3 Our models estimate that larvae consume 0.66, 1.67 and 3.30 mg of pollen during the second, third and fourth stadia, respectively. Adults consumed an estimated 13.15 mg during anthesis. 4 The relevance of our results to ecological risk assessment of transgenic insecticidal corn and predator life history strategies is discussed. The results presented here are a first attempt to quantify pollen consumption by a predator, and future areas of research are suggested.