寨卡病毒检测研究进展

寨卡病毒病是近年来在非洲、亚洲、南美洲等地流行的一种隐性传染病.该病由寨卡病毒(Zika virus,ZIKV)感染导致,虽然患者或携带者的病情并不明显,或在短期内很难察觉.但由于近些年来的突然流行,患者数目的 急剧增加,而且各国间贸易往来愈加繁荣,亦加快了该疾病流行的步伐.疾病的防治离不开确切的诊断,如何快速、准确检测出寨卡病毒不容小觑,是急需解决的世界性难题之一.     

Effect of modification of tRNA nucleotide 37 on the tRNA interaction with the A and P sites of the Escherichia coli 70S ribosome

The modified nucleotide 3′ of the tRNA anticodon is an important structural element that regulates the codon-anticodon interaction in the ribosome by stacking with codon-anticodon bases. The presence and identity (pyrimidine, purine, or modified purine) of this nucleotide significantly affects the energy of stacking in the A and P sites of the ribosome. Modification of nucleotide 37 does not contribute to stacking in the A site of the 70S ribosome, while its effect is substantial in the P site. The enthalpies of tRNA interactions with the A and P sites in the ribosome are similar and considerably lower than the enthalpy of the interactions of two tRNAs with the cognate anticodons in solution, suggesting that the ribosome contributes to the enthalpy-related portion of the free energy of tRNA binding by directly forming additional interactions with tRNA or by indirectly stabilizing the conformation of the codon-anticodon complex. In addition to stacking, tRNA binding in the A and P sites is further stabilized by interactions that involve magnesium ions. The number of ions involved in the formation of the tRNA-ribosome complex depends on the identity of tRNA nucleotide 37.     

坝上地区农田及两种恢复生境中蜘蛛多样性与群落特征

蜘蛛是农田生态系统中重要的自然天敌,其生物多样性及群落特征直接决定了农田的害虫控制等生态系统服务功能质量。农田及其周边的恢复生境是蜘蛛重要的栖息地。本研究采用陷阱法,对河北省张家口市崇礼区871、1360、1635 m 3个海拔农田、自然恢复草地及人工修复林地的蜘蛛群落的物种组成、物种多样性和功能特征进行研究,分析不同恢复生境中蜘蛛群落特征。结果表明: 不同生境蜘蛛的物种多样性指数差异明显,人工修复林地蜘蛛的多度为124.3只,显著高于自然恢复草地(70.1)及农田(38.6)的蜘蛛多度;人工修复林地(16.3)与自然恢复草地(21.4)的物种丰富度没有显著差别,但均显著高于农田(8.9);人工修复林地(2.04)及自然恢复草地(2.05)的Shannon多样性指数差异不显著,且均显著高于农田(1.55)。3种生境的蜘蛛群落组成均具有显著差异;蜘蛛体长与蜘蛛捕猎类型呈正相关,大型蜘蛛倾向于通过捕猎获取食物;自然恢复草地与农田蜘蛛以游猎型为主,而人工修复林地倾向于拥有更多的结网型蜘蛛,高海拔地区的蜘蛛体积通常较小。自然恢复草地与人工修复林地均可以提升蜘蛛群落多样性,在区域生物多样性保护中起重要作用;不同生境蜘蛛群落组成出现了显著分化,即蜘蛛群落总体的功能特征发生改变和保留了部分生境特有种。2种恢复生境蜘蛛多样性指标优于农田生境,且2种恢复生境物种组成存在差异,均具有保护特有种的功能,研究结果对农田及区域尺度蜘蛛生物多样性保护与恢复具有指导意义。     

Effect of Agglutinins from Rhizobium leguminosarum Strain 252 on the Activity of Hydrolytic Enzymes

Cells of the nitrogen-fixing soil bacterium Rhizobium leguminosarum 252 and its hemagglutination-deficient mutant strain 252/7 were found to possess the activities of a variety of hydrolytic enzymes. The agglutinin proteins of rhizobia diminished β-glucosidase activity, pectinolytic activity, and acid and alkaline phosphatase activities while completely inhibiting proteolytic enzyme activity in the bacterial cell. The results here show that rhizobial agglutinins are capable of affecting enzyme functioning in Rhizobium. Received: 18 November 1999 / Accepted: 10 February 2000     

The peroxisome proliferator activated receptor δ is required for the differentiation of THP-1 monocytic cells by phorbol ester

BACKGROUND: PPARdelta (NR1C2) promotes lipid accumulation in human macrophages in vitro and has been implicated in the response of macrophages to vLDL. We have investigated the role of PPARdelta in PMA-stimulated macrophage differentiation.The THP-1 monocytic cell line which displays macrophage like differentiation in response to phorbol esters was used as a model system. We manipulated the response to PMA using a potent synthetic agonist of PPARdelta, compound F. THP-1 sub-lines that either over-expressed PPARdelta protein, or expressed PPARdelta anti-sense RNA were generated. We then explored the effects of these genetic modulations on the differentiation process. RESULTS: The PPARdelta agonist, compound F, stimulated differentiation in the presence of sub-nanomolar concentrations of phorbol ester. Several markers of differentiation were induced by compound F in a synergistic fashion with phorbol ester, including CD68 and IL8. Over-expression of PPARdelta also sensitised THP-1 cells to phorbol ester and correspondingly, inhibition of PPARdelta by anti-sense RNA completely abolished this response. CONCLUSIONS: These data collectively demonstrate that PPARdelta plays a fundamental role in mediating a subset of cellular effects of phorbol ester and supports observations from mouse knockout models that PPARdelta is involved in macrophage-mediated inflammatory responses.     

Production and analytical properties of antibodies with high specificity to zearalenone

The time course of production, specificity, and analytical potential of anti-zearalenone polyclonal rabbit antibody synthesized by formaldehyde condensation and conjugated to bovine serum albumin were investigated. The relative cross-reactivities with natural analogues were: zearalenone, 100%; alpha-zearalenol, 0.15%; and beta-zearalenol, < 0.02%. With synthetic analogues: zearalanone, 31.7% and alpha-zearalanol, 0.12%. An enzyme immunoassay for zearalenone with a sensitivity of 0.1 ng/ml was developed on the basis of these antibodies and solid-phase conjugates homologous to the immunogen in the method of synthesis.     

Hemopoietic precursor cells in the intima of the atheromatous human aorta

Granulocyte-macrophage progenitor cells (CFU-GM) were found in the intima of human atheromatous aorta. Granulocyte-macrophage colonies were recovered on the 14th day of culturing of intimal cells suspensions on agar. Medium conditioned by normal leukocytes in the presence of phytohaemagglutinin was used as a source of the colony-stimulating factor. Grossly normal and atheromatous intima contained different number of CFU-GM. No GM were recovered from fibrous plaques. By light and electron microscopies, the injured aortic intima contained the clusters of blood-born cells that were at various stages of granulocytopoiesis (including blasts and mature cells) and poorly differentiated lymphocyte-like cells. The results obtained suggest that in human aortic intima proliferation and differentiation of CFU-GM occur at early stages of atherogenesis, prior to fibrous plaque formation.     

1H-NMR spin-spin relaxation time assessment of the reflection coefficient of the Triticale seed cell wall–plasmalemma barrier to mannitol

The ¹H-NMR spin-spin relaxation time (T₂) in Triticale seeds swelling in external osmotica, polyethylene glycol 8000 or mannitol can identify both bound and free water. At the same water content, the free water spin-spin relaxation time increases for seeds imbibed with the mannitol solution, demonstrating inadequate water potential adjustment. The exchange rate of free/bound water molecules is apparently influenced by the driving force for water flow. The reciprocal lifetime of free water molecules, as a measure of water flow through the main cell barrier, was obtained. From a model of the seed as a resistance–capacitor network for water flow, a method was derived for calculating the reflection coefficient σ as a lifetime ratio of the free water molecules in seeds imbibed with two different osmotica (one penetrating across the main cell barrier and one not penetrating) at the same water potential. The ¹H-NMR method and the classical method based on volume rate changes yielded reflection coefficients for mannitol for the cell wall–plasmalemma barrier of 0.78 ± 0.08 and 0.68 ± 0.06, respectively.     

猪蛔虫生长发育与繁殖力的研究

经对猪蛔虫雌虫体长,体重,子宫瞬间怀卵总量,相对毓力测定,发现怀卵总量与体长,体重有密切关系,呈正相关,还发现相对繁殖力,以体重１．０１－３．００ｇ,范围最佳,繁殖能力最强。