Characterization of an inducible HSP70 gene in Chilo suppressalis and expression in response to environmental and biological stress.

The highly conserved heat shock protein 70 (HSP70) contributes to survival at a cellular level and greatly enhances stress tolerance in many organisms. In this study, we isolate and characterize Cshsp702, which encodes an inducible form of HSP70 in the rice stem borer, Chilo suppressalis. Cshsp702 does not contain introns; the translational product is comprised of 629 amino acids with an isoelectric point of 5.69. Real-time quantitative PCR revealed that Cshsp702 was expressed at maximal levels in hemocytes and was minimally expressed in the midgut. Expression of Cshsp702 in response to a range of temperatures (-11 to 43 °C) indicated significant induction by extreme cold and hot temperatures, with maximum expression after 2 h at 42 °C. The induction of Cshsp702 in response to the endoparasite Cotesia chilonis was also studied; interestingly, Cshsp702 expression in C. suppressalis was significantly induced at 24 h and 5 days, which correspond to predicted times of C. chilonis feeding and growth, respectively. The potential induction of Cshsp702 as an inflammatory response due to parasitic stress is discussed. In conclusion, Cshsp702 is induced in response to both environmental and biotic stress and plays an important role in the physiological adaptation of C. suppressalis.

Identification and Functional Analysis of the First Aquaporin from Striped Stem Borer, Chilo suppressalis.

Aquaporins are integral membrane proteins some of which form high capacity water-selective channels, promoting water permeation across cell membranes. In this study, we isolated the aquaporin transcript (CsDrip1) of Chilo suppressalis, one of the important rice pests. CsDrip1 included two variants, CsDrip1_v1 and CsDrip1_v2. Although CsDrip1_v2 sequence (>409 bp) was longer than CsDrip1_v1, they possessed the same open reading frame (ORF). Protein structure and topology of CsDrip1 was analyzed using a predicted model, and the results demonstrated the conserved properties of insect water-specific aquaporins, including 6 transmembrane domains, 2 NPA motifs, ar/R constriction region (Phe69, His194, Ser203, and Arg209) and the C-terminal peptide sequence ending in "SYDF." Our data revealed that the Xenopus oocytes expressing CsDrip1 indicated CsDrip1 could transport water instead of glycerol, trehalose and urea. Further, the transcript of CsDrip1 expressed ubiquitously but differentially in different tissues or organs and developmental stages of C. suppressalis. CsDrip1 mRNA exhibited the highest level of expression within hindgut and the third instar larvae. Regardless of pupae and adults, there were significantly different expression levels of CsDrip1 gene between male and female. Different from at low temperature, the transcript of CsDrip1 in larvae exposed to high temperature was increased significantly. Moreover, the mRNA levels of CsDrip1 in the third instar larvae, the fifth instar larvae, pupae (male and female), and adults (male and female) under different humidities were investigated. However, the mRNA levels of CsDrip1 of only female and male adults were changed remarkably. In conclusions, CsDrip1 plays important roles in maintaining water homeostasis in this important rice pest.

Characteristics and expression of genes encoding two small heat shock protein genes lacking introns from Chilo suppressalis.

Small heat shock proteins (sHSPs) constitute a large, diverse, and functionally uncharacterized family of heat shock proteins. To gain insight regarding the function of sHSPs in insects, we identified genes encoding two sHSPs, Cshsp22.9b and Cshsp24.3, from the rice pest Chilo suppressalis. The cDNAs of Cshsp22.9b and Cshsp24.3 encoded proteins of 206 and 216 amino acids with isoelectric points of 5.79 and 9.28, respectively. Further characterization indicated that both Cshsp22.9b and Cshsp24.3 lacked introns. Real-time quantitative PCR indicated that Cshsp22.9b and Cshsp24.3 were expressed at higher levels within the fat body as compared to other tissues (head, epidermis, foregut, midgut, hindgut, Malpighian tubules, and hemocytes). Expression of Cshsp22.9b and Cshsp24.3 was lowest in the hindgut and Malpighian tubules, respectively. Cshsp22.9b and Cshsp24.3 showed identical patterns in response to thermal stress from -11 to 43 °C, and both genes were up-regulated by hot and cold temperatures. The mRNA (messenger ribonucleic acid) expression levels of Cshsp22.9b (KY701308) and Cshsp24.3 (KY701309) were highest after a 2-h exposure at 39 °C and started to decline at 42 °C. In response to cold temperatures, both Cshsp22.9b and Cshsp24.3 showed maximal expression after a 2-h exposure to -3 °C. The two Cshsps were more responsive to hot than cold temperature stress and were not induced by mildly cold or warm temperatures. In conclusion, Cshsp22.9b and Cshsp24.3 could play a very important role in the regulation of physiological activities in C. suppressalis that are impacted by environmental stimuli.

Leucobacter triazinivorans sp. nov., a s-triazine herbicide prometryn-degrading bacterium isolated from sludge.

A Gram-stain-positive, rod-shaped, non-motile bacterial strain, designated JW-1T, was isolated from activated sludge collected from the outlet of an aeration tank in a prometryn-manufacturing plant, located in Binzhou City, Shandong province, PR China. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that strain JW-1T belongs to the genus Leucobacter and its closest neighbours are 'Leucobacter kyeonggiensis' F3-P9 (98.95 % similarity), Leucobacter celer subsp. astrifaciens CBX151T (98.62 %), Leucobacter celer subsp. celer NAL101T (98.53 %), Leucobacter chromiiresistens JG31T (97.86 %) and Leucobacter chironomi DSM 19883T (97.37 %). DNA-DNA hybridization values with the above strains were <55 %. The DNA G+C content of strain JW-1T was 72.6 mol%. The major fatty acids of strain JW-1T were iso-C16 : 0, anteiso-C15 : 0, anteiso-C17 : 0 and iso-C15 : 0. The predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol and glycolipid. The predominant menaquinone was MK-11. The cell wall amino acids were 2,4-diaminobutyric acid, alanine, glutamic acid, glycine and threonine. Based on the molecular and chemotaxonomic data, as well as the physiological and biochemical characteristics, strain JW-1T is considered to represent a novel species of the genus Leucobacter, for which the name Leucobacter triazinivorans is proposed. The type strain is JW-1T (=DSM 105188T=LMG 30083T).

Inhibition of tyrosinase by cherimoya pericarp proanthocyanidins: Structural characterization, inhibitory activity and mechanism.

In this study, the structure of proanthocyanidins purified from cherimoya (Annona squamosa) pericarp was analyzed by ESI-QTOF-MS and HPLC analyses. The result indicated that these compounds were procyanidin-type proanthocyanidins, consisting mainly of (epi)catechin units linked b y B-type interflavan bonds. The analyses of enzymology showed that the activities of monophenolase and diphenolase of tyrosinase could be powerfully inhibited by the proanthocyanidins. Further researches on the inhibition mechanism demonstrated that they were reversible and competitive inhibitors with the KI value of 27.1±3.1µg/mL. These inhibitors quenched the fluorescence of tyrosinase through a static quenching mechanism and spontaneously formed proanthocyanidins-enzyme complex. Fluorescence changes of proanthocyanidins in the presence of copper ion suggested that the interactions could reduce the fluorescence intensity of these polymers and the molecular docking analysis revealed that copper irons of the enzyme could be chelated by adjacent hydroxyl groups on the B ring of proanthocyanidins. Moreover, proanthocyanidins were proved to be efficient quencher of substrates. These results would lay scientific foundation for their farther application in food and medicine industry.

[Preliminary study on efficacy and mechanism of Atractylodes Macrocephelae Rhizoma extracts in metabolic hyperlipidemia rats].

Hyperlipidemia is a major factor causing coronary heart disease and atherosclerosis. The high-density lipoprotein cholesterol (HDL-C) is a major indicator for measuring lipid levels. However, there is no an effective medicine that can obviously increase HDL-C at present. According to previous laboratory studies, atractylodes macrocephalae extracts could significantly increase HDL-C level. In this study, the metabolic hyperlipidemia rat model was established by feeding high-sugar and fat diets and alcohol-drinking to explore the effect and mechanism of atractylodes macrocephalae extracts on hyperlipidemia rats. According to the findingins, different doses of atractylodes macrocephalae extracts could reduce the levels of TC, TG, LDL-C, ACAT and increase the contents of LCAT, HDL-C. Particularly, the atractylodes macrocephalae extracts (100 mg · kg(-1) group showed increase in HDL-C by about 50% and significant declines in HMG-CoA reductase, TC, TG. In conclusion, Atractylodes Macrocephelae Rhizoma extracts could effectively regulate the dyslipidemia of hyperlipidemia rats, especially on HDL-C. Its mechanism may be related to reduction in cholesterol synthesis by inhibiting HMG-CoA reductase in livers and increase in lipid metabolism and transport by regulating LCAT and ACAT levels.

[Effect of improper diets on blood viscosity in SD rats in high-salt and fat diet and alcohol abuse simulation model].

OBJECTIVE: To observe the effect of composite factors, like long-term high-salt & fat diet and alcohol abuse on blood viscosity and blood pressure in rats, and compare with a model induced by high molecular dextran, in order to build a chronic hyperviscosity aminal model which is similar to human hyperviscosity in clinic and lay a foundation for efficacy evaluation on traditional Chinese medicines. METHOD: Male SD rats were randomly divided into the normal group, the high molecular dextran (HMD) group and the high salt & fat and alcohol (HSFA) group. The HMD group was given normal diet and water for 23 day and then 10% HMD through tail vein for 5 days. The HSFA group was fed with high salt and high fat diets every day and alcohol for 20 h x d(-1) for 13 weeks. After the modeling, whole blood viscosity and plasma viscosity were measured in the 5th, 8th and 11th week. Blood pressure was measured in the 5d, 7h, and 10th week. Red cell count (RBC) and hematocrit (HCT) were measured in the 11th week. PAgT, Fb, ET-1, NO, PGI, TXA2 contents of the normal group and the HSFA group were measured in the 13th week, and IECa21 content was measured with flow cytometry. Result: After the modeling, the HMD group was in good conditions with glossy hairs and active behaviors. The HSFA group was depressed with withered hairs and less activities. During the 5th-11th weeks, the HMD group and the HSFA group showed higher values in high and low shear whole blood viscosity (WBV) than the normal control group. The plasma viscosity (PV) of HMD rats was significantly increased only in the 5th week, and that of HSFA rats significantly increased in the 8"' and 11th week, particularly in the 11'h week. In the 111h week, the HSFA group showed significant increases in RBC and HCT. After the modeling, the blood pressure of HMD rats showed no significant changes, but the blood pressure of HSFA rats significantly increased during 7' and 101h weeks, particularly in the 10"' week. In the 13th week, PAgT, IECa2+, Fb, ET-1 of HSFA rats significantly increased, but with decreases in NO and PGI2. CONCLUSION: Long-term high salt & fat and alcohol diets can cause abnormal blood viscosity in rats. WBV significantly increased since the 5th week in rats, and PV increased since the 8th week. The mechanism for increasing BV may be: (1) increases in RBC, HCT, and IECa2+, (2) PAgT increase, (3) Fb content increase, or (4) TXA2/PGI2, ET-1/NO imbalance. Although the modeling time with the method is longer than that with the HMD method, the model is more stable and moderate, and could lead to abnormal increases in WBV and PV; Whereas the HMD method only induced transient increase in plasma viscosity and abnormal increase in SBP. The model is more similar to traditional Chinese medicine syndromes and pathogenesis, with higher value for studies on efficacy of traditional Chinese medicines.

[Determination of heavy metals in artificial soil on railway rock-cut slopes by microwave digestion-AAS].

The purpose of this paper is as follows: (1) Optimizing the parameters of microwave digestion-atomic absorption spectroscopy (AAS) and establishing method for the determination of heavy metals in artificial soils. (2) Evaluating heavy metal pollution conditions in artificial soil samples from railway rock-cut slopes. The results showed that the mixture of HNO3-H2O2-HF was found to have the best digestion efficiency; under the optimized conditions, the recoveries of the method ranged from 95% to 105%; the measurement precision and the relative deviation were less than 4% and 5%, respectively; the concentrations of Cd, Pb and Zn were significantly higher in the artificial soil on railway rock-cut slope than in the control soil, and they were 4.7, 1.3 and 1.2 times as much as the control soil, respectively; compared to the contents of Cr, Cu and Fe in control soils, there was no significant difference. This research will provide a reliable method for determining metal elements in artificial soils on rock-cut slopes and a theoretical basis for the management of the railway rock-cut slopes.