Chlorine transport in a small catchment in southeast Sweden during two years

Previous studies have revealed that chlorine participates in a complex biogeochemical cycle in soil, which suggests that the transport of chloride through catchments may also be influenced. The present study is based on field observations of organic carbon, chloride (Cl_in), and chlorinated organic carbon (Cl_org) in precipitation, soil, and runoff over a 2-year period from a small, forested catchment in southeast Sweden. The study reveals that (1) the soil pool is dominated by Cl_org, (2) the input via wet deposition and output of Cl_in via runoff is 30 times smaller than the total storage of chlorine (Cl_in + Cl_org) in soil, and (3) the transport is dominated by Cl_in. The organic matter that entered the outlet of the catchment was more chlorinated in the autumn than during the rest of the year, and rain events taking place in low-flow periods had a greater influence on TOC, Cl_org, and Cl_in than did rain events taking place in high-flow periods. The seasonal pattern in combination with the low-flow versus high-flow pattern and previous findings of increasing chlorine-to-carbon ratios with soil depth suggests that the chlorine-to-carbon ratio variation in the leached organic matter is due that water preferentially comes from deeper layers in low-flow conditions. This study provides well-founded estimates of Cl_org and Cl_in storage and fluxes for the studied catchment; however, the processes underlying the observed seasonal Cl_org variations and transportation processes need further study.     

Solution structure of the recombinant penaeidin-3, a shrimp antimicrobial peptide

Penaeidins are a family of antimicrobial peptides of 47-63 residues isolated from several species of shrimp. These peptides display a proline-rich domain (N-terminal part) and a cysteine-rich domain (C-terminal part) stabilized by three conserved disulfide bonds whose arrangement has not yet been characterized. The recombinant penaeidin-3a of Litopenaeus vannamei (63 residues) and its [T8A]-Pen-3a analogue were produced in Saccharomyces cerevisiae and showed similar antimicrobial activity. The solution structure of the [T8A]-Pen-3a analogue was determined by using two-dimensional 1H NMR and simulated annealing calculations. The proline-rich domain, spanning residues 1-28 was found to be unconstrained. In contrast, the cysteine-rich domain, spanning residues 29-58, displays a well defined structure, which consists of an amphipathic helix (41-50) linked to the upstream and the downstream coils by two disulfide bonds (Cys32-Cys47 and Cys48-Cys55). These two coils are in turn linked together by the third disulfide bond (Cys36-Cys54). Such a disulfide bond packing, which is in agreement with the analysis of trypsin digests by ESI-MS, contributes to the highly hydrophobic core. Side chains of Arg45 and Arg50, which belong to the helix, and side chains of Arg37 and Arg53, which belong to the upstream and the downstream coils, are located in two opposite parts of this globular and compact structure. The environment of these positively charged residues, either by hydrophobic clusters at the surface of the cysteine-rich domain or by sequential hydrophobic residues in the unconstrained proline-rich domain, gives rise to the amphipathic character required for antimicrobial peptides. We hypothesize that the antimicrobial activity of penaeidins can be explained by a cooperative effect between the proline-rich and cysteine-rich features simultaneously present in their sequences.     

Allelopathic potential of sweet potato (Ipomoea batatas) germplasm resources of Yunnan Province in southwest China

A laboratory bioassay was conducted to determine the allelopathic potentials of aqueous extracts from either roots or leaves of seventeen sweet potato [Ipomoea batatas L. (Lam)] cultivars (SP0, SP1, SP2, SP3, SP4, SP5, SP6, SP7, SP9, SP10, SP11, SP13, SP14, SP15, SP16, SP18, and SP19). Most inhibitory rates on Lactuca sativa calculated for leaf or root extracts from the seventeen sweet potato cultivars exhibited positive values and significantly increased with increasing concentration. Germination was totally inhibited at a concentration of 0.05 g·mL^?1 for leaf water extracts of SP13, SP15, SP18 and at a concentration of 0.05 g·mL^?1 for both leaf and root water extracts of SP19. Inhibition of root length was clearly greater than inhibition of shoot length for both leaf and root water extracts. Biomass inhibition increased with increasing concentration, but some cultivars showed stimulatory effects at low concentrations, and inhibition was generally more pronounced for root water extracts than for leaf water extracts. Moreover, most synthetical inhibitory rates for both leaf and root water extracts from the seventeen cultivars exhibited positive values and significantly increased with increasing concentration. Comparing the synthetical inhibitory rates for both leaf and root water extracts among the seventeen cultivars, SP19, SP6, SP11, and SP7 had the highest allelopathic inhibition. The inhibitory activity on germination index was the greatest, followed by germination rate, root length, biomass, and shoot length in all bioassays. Inhibition by leaf water extracts was generally greater than inhibition by root water extracts, except in the case of shoot length or biomass. Overall, we conclude that all seventeen sweet potato cultivars have strong inhibitory effects on L. sativa, but that these effects vary with cultivar and plant part, with SP19, SP6, SP11, and SP7 exhibiting the highest rates of allelopathic inhibition.     

Biomorphometric characteristics of different types of sensilla detected on the antenna of Helicoverpa armigera by scanning electron microscopy

A morphometric study on H. armigera antenna showed four styles of sensilla, i.e., styloconica, chaetica, coeloconica, and trichodea, and their numbers were estimated. Sensilla trichodea detect inter and intraspecific communication signals and was the most numerous. They were divided into three types: type I, the longest, with a length of 34.04 ± 3.16 μm and about 2.16 to 2.42 μm in diameter at its base; 2) type II, intermediate, with a length of 22.58 ± 0.77 μm and basal diameter of 1.8–2.52 μm; 3) type III, the shortest sensilla trichodea, with a length of 7.62 ± 0.4 μm and a range in diameter similar to that of type II. The length of the female sensilla trichodea was longer than that of the male. The total number of sensilla trichodea was estimated to be 7520 on the antenna of the female, and 6831 on the male antenna. The lengths of the sensilla trichodea type I and type III were significantly different on male (t = 4.6881, P = 0.0034) and female antenna (t = 18.9852, P = 0.0001). An estimation of the predicted surface area of the most numerous type I on sampled segments between the 12th and 20th segments from a female of H. armigera showed a surface area of 5 × 10³ μm² and a sensillar density of 38 sensilla/10³ μm². The fraction of sensilla-occupied surface area was 0.4 μm².     

Survivin expressions in human hepatoma HepG2 cells exposed to ionizing radiation of different LET

Survivin is a member of the inhibitors of apoptosis (IAP) protein family that interferes with post-mitochondrial events including activation of caspases. To examine the regulation of survivin expression in response to irradiation with different linear energy transfer (LET), human hepatoma HepG2 cells were irradiated in vitro with X-rays and carbon ions. Cellular sensitivities to low- and high-LET radiation were determined by colony formation. Survivin expression at mRNA and protein level were measured with RT-PCR and Western blot analyses, respectively. Radiation-induced cell cycle arrest and apoptosis were investigated with flow cytometry. We found that low-LET X-rays induced dose-dependent increases in survivin expression. After exposure to high-LET carbon ions, survivin expression gradually increased from 0 to 4 Gy, and then declined at 6 Gy. More pronounced survivin expression, stronger G(2)/M phase arrest was observed after exposure to carbon ions in comparison with X-rays at doses from 0 to 4 Gy. These observations indicate that there is a differential survivin expression in response to different LET radiations and the cycle arrest mechanism may be associated with it. In addition, our data on induction of apoptosis are compatible with the assumption that survivin expression induced by low-LET X-rays radiation may play a critical role in inhibiting apoptosis. However, after irradiation with ions, an anti-apoptotic function of survivin is not evident, possibly because of the serious damage produced by densely ionizing radiation.     

Geldanamycin induces production of heat shock protein 70 and partially attenuates ototoxicity caused by gentamicin in the organ of Corti explants

Background  

Heat shock protein 70 (HSP70) protects inner ear cells from damage and death induced by e.g. heat or toxins. Benzoquinone ansamycin antibiotic geldanamycin (GA) was demonstrated to induce the expression of HSP70 in various animal cell types. The aim of our study was to investigate whether GA induces HSP70 in the organ of Corti (OC), which contains the auditory sensory cells, and whether GA can protect these cells from toxicity caused by a common aminoglycoside antibiotic gentamicin.     

The Association of Early Childhood Cognitive Development and Behavioural Difficulties with Pre-Adolescent Problematic Eating Attitudes

Objectives

Few studies have prospectively investigated associations of child cognitive ability and behavioural difficulties with later eating attitudes. We investigated associations of intelligence quotient (IQ), academic performance and behavioural difficulties at 6.5 years with eating attitudes five years later.

Methods

We conducted an observational cohort study nested within the Promotion of Breastfeeding Intervention Trial, Belarus. Of 17,046 infants enrolled at birth, 13,751 (80.7%) completed the Children''s Eating Attitude Test (ChEAT) at 11.5 years, most with information on IQ (n = 12,667), academic performance (n = 9,954) and behavioural difficulties (n = 11,098) at 6.5 years. The main outcome was a ChEAT score ≥85^th percentile, indicative of problematic eating attitudes.

Results

Boys with higher IQ at 6.5 years reported fewer problematic eating attitudes, as assessed by ChEAT scores ≥85^th percentile, at 11.5 years (OR per SD increase in full-scale IQ = 0.87; 0.79, 0.94). No such association was observed in girls (1.01; 0.93, 1.10) (p for sex-interaction = 0.016). In both boys and girls, teacher-assessed academic performance in non-verbal subjects was inversely associated with high ChEAT scores five years later (OR per unit increase in mathematics ability = 0.88; 0.82, 0.94; and OR per unit increase in ability for other non-verbal subjects = 0.86; 0.79, 0.94). Behavioural difficulties were positively associated with high ChEAT scores five years later (OR per SD increase in teacher-assessed rating = 1.13; 1.07, 1.19).

Conclusion

Lower IQ, worse non-verbal academic performance and behavioural problems at early school age are positively associated with risk of problematic eating attitudes in early adolescence.