地里红恙虫蚴叮咬鼠类的试验

地里红恙虫 Trombicula akamushi var.deliensis(Walch,1923)是广州及国内许多地区已经证实的主要的恙虫病的媒介。因此本恙虫的生态研究从恙虫病流行病学的角度看有重要的意义。本文以我们自己培养的地里红恙虫蚴进行鼠类的叮咬试验。试验的目的,一方面想获得有关恙虫蚴叮咬鼠类的一些更具休的科学资料,这在恙虫病流行病学上     

地里恙螨两种形态及其对杀螨药剂不同耐性的研究

地里恙螨在世界上很多地区是恙虫病的主要传染媒介,我国大陆上福建和广东两地,也得到了证明。几年来我们以地里恙螨为主,进行了品种调查、生态以及防灭方法的研究,发现平潭岛上有两种不同形态特征的地里恙螨,它们的形态大小、色泽、身体各部位的特征以及生活史等,都有显著的差别。更值得注意的是对一些杀螨药剂也表现出不     

济南鼠类恙螨初步调查

一.绪言 恙螨幼虫时期是恙虫病(恙虫斑疹热或日本河流热)的主要传播媒介。在我国恙虫病流行地区的观察和研究的结果,得知啮齿类动物尤其鼠类是人体恙虫病的储存宿主。     

地里红恙虫孳生场所的研究

恙虫孳生场所的调查研究在恙虫病的流行病学和预防上有重要的意义。这种研究一方面使我们能够明瞭恙虫的孳生环境,作为消灭恙虫的根据,另一方面可以找出恙虫病之所以能够在一个地区流行的原因。根据国内外的文献看来,地里红恙虫(Trombiculaakamushi var.deliensis)和另外一个非常相近的种类——红恙虫(T.akamushi)是世界     

恙虫病立克次体分子生物学研究进展

恙虫病立克次体（Rickettsiatsut－sugamushi,Rt）是一类以恙螨为传播媒介,专性细胞内奇生的微生物。恙虫病（ScrubTxpes）是一种自然疫源性疾病,主要流行于亚洲、太平洋一带。在我国,以往经病原学证实恙虫病只分布于长江以南和台湾省,而1986年以来山东及江苏相继发生了恙虫病暴发流行,90年代初期新疆、天津北部农村和山西侯马也发现了恙虫病流行。1991－1995年我所在东北三省从野鼠和恙虫中共分离出19株Rt,首次证实东北地区也存在恙虫病的自然疫源地。可见恙虫病仍是一值得注意的问题,要弄清恙虫病在我国的流行情况仍需采用先进…     

应用PCR技术检测媒介恙螨体内恙虫病立克次体(英语)

本文PCR技术的引物是参考恙虫病立克次体Karp株Sta 58序列设计合成的一对DNA引物.以恙虫病立克次体DNA为模板,成功扩增长约1kb的DNA片段.该对引物首次应用于人工成虫腹内接种羔虫病立克次体(人工接种法)和幼虫叮咬恙虫病鼠(叮咬病鼠法)的我国主要恙虫病媒介地里纤羔螨的研究.PCR检测人工接种法成虫的不同时期和经卵传递的子代立克次体DNA均获满意结果,立克次体在恙螨体内生长持续360天及产卵孵出的第4代幼虫均呈阳性.叮咬病鼠法立克次体在恙螨亲代饱食蚴、若蛹、若虫、成虫及第2代子产代幼虫,PCR检测均呈阳性.结果显示PCR技术检测恙螨体内恙虫病立克次体的特异性和敏感性高;体外基因扩增检测恙螨体内及鼠宿主体内立克次体是流行病学调查的新的敏感方法.本法为恙虫病分子体流行病学调查提供了新的应用技术,亦为临床病人诊断提供了敏感方法.     

恙虫爬行速度的试验

恙虫蚴的活动及其和外界环境条件的关系曾经引起许多科学家(例如Jenkins,1948;Richards,1950;Wharton ＆ Fuller,1952等)的注意,并且做过仔细的观察和研究。这些工作在了解恙虫病的传播、媒介恙虫的活动和环境因素三者之间的关系时有重要的意义。但是,总的来说,这方面的研究,不但面不够广,深度也很不够。本文以地里红恙虫Trombicula akamushi var.deliensis(Walch,1923)与巨多齿(恙虫)Acomatacarus majesticusChen ＆ Hsu,1955为研究的对象。试验的目的主要想了解外界环境条件,特别是温度对各期恙虫爬行速度的影响。关于这方面的科学资料,上述两种恙虫都还没有。     

在广东发现两种恙螨蚴(一新种及一新变种)的分类研究

自从我们在1951年9月6日首次在广州采集到恙虫病的传染媒介“地里恙螨”蚴以后,对广东的恙螨调查研究已经陆续地展开。1952年,甘怀杰氏等在广州市较有系统地调查了恙虫病的流行因素,共检查了老鼠1,238只,采集到恙螨蚴62,504只,分隶于4个属,共5种。1955年,陈心陶、徐秉锟二氏描述了中国恙虫(螨)蚴12种,包括1新属、6新种及2新变种;连同我国台湾省早已发现的6种,共18种。 我们在1952年及1956年曾在广东采集到两种恙螨蚴,我们认为是文献上未曾记     

地里红恙虫蚴群集现象的研究

许多科学家都观察到未进食的恙虫蚴有群集在某一点的现象。这种现象不是单纯的恙虫生态学的问题,从恙虫病流行病学的角度看也有现实的意义。根据我们分析一些恙虫病病例被恙虫蚴叮咬的地点的结果,除了和媒介恙虫孳生点的分布有关外,可能和恙虫蚴的“群集性”也有关系。为了给进一步探索这问题提供足够的材料,我们观察了地里红恙虫[Trombicula akamushi var.de-liensis(Walch,1923)]蚴的“群集现象”。     

云南纤恙螨属三新种

在调查云南省恙虫病传播媒介时,采到一批恙螨标本,经鉴定发现纤恙螨属(Lepto-trombidium)三新种。正模和副模标本均保存于昆明军事医学研究所和上海第一医学院。 二叉纤恙螨Leptotrombidium(L.)dichotogalium新种(图1-5) 标本材料 正模与9副模。以黑色赛璐珞胶片诱获于勐腊县叉河,湿性雨林地面落叶上,1964,IX.向容炯、赵天顺等采。     

Collagen-like triple helix formation of synthetic (Pro-Pro-Gly)10 analogues: (4(S)-hydroxyprolyl-4(R)-hydroxyprolyl-Gly)10, (4(R)-hydroxyprolyl-4(R)-hydroxyprolyl-Gly)10 and (4(S)-fluoroprolyl-4(R)-fluoroprolyl-Gly)10.

For the rational design of a stable collagen triple helix according to the conventional rule that the pyrrolidine puckerings of Pro, 4-hydroxyproline (Hyp) and 4-fluoroproline (fPro) should be down at the X-position and up at the Y-position in the X-Y-Gly repeated sequence for enhancing the triple helix propensities of collagen model peptides, a series of peptides were prepared in which X- and Y-positions were altogether occupied by Hyp(R), Hyp(S), fPro(R) or fPro(S). Contrary to our presumption that inducing the X-Y residues to adopt a down-up conformation would result in an increase in the thermal stability of peptides, the triple helices of (Hyp(S)-Hyp(R)-Gly)(10) and (fPro(S)-fPro(R)-Gly)(10) were less stable than those of (Pro-Hyp(R)-Gly)(10) and (Pro-fPro(R)-Gly)(10), respectively. As reported by B?chinger's and Zagari's groups, (Hyp(R)-Hyp(R)-Gly)(10) which could have an up-up conformation unfavorable for the triple helix, formed a triple helix that has a high thermal stability close to that of (Pro-Hyp(R)-Gly)(10). These results clearly show that the empirical rule based on the conformational preference of pyrrolidine ring at each of X and Y residues should not be regarded as still valid, at least for predicting the stability of collagen models in which both X and Y residues have electronegative groups at the 4-position.     

Synthesis and luminescence properties of a blue-emitting Sr(3.5) Y(6.5) O(2) (PO(4) )(1.5) (SiO(4) )(4.5) :Eu(2+) phosphor

A novel blue‐emitting Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:Eu²⁺ phosphor was synthesized via a solid‐state reaction. Powder X‐ray diffraction (XRD) analysis demonstrated that the Sr_3.5Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5 host had a hexagonal crystal structure in the space group P6₃/m and unit cell parameters a = 9.418 Å, c = 6.900 Å. The as‐prepared phosphor showed a blue emission and all the main emission peaks were located at around 466 nm for different excitation wavelengths of 297, 333 and 391 nm. The temperature dependence of the photoluminescence property was investigated in the range 20–250 °C, and the emission intensity decreased to 71% of the initial value at room temperature on increasing the temperature to 150 °C. According to the classical theory of fluorescent thermal quenching, the activation energy (ΔE) for the thermal quenching luminescence of the as‐prepared Sr_3.45Y_6.5O₂(PO₄)_1.5(SiO₄)_4.5:0.05Eu²⁺ phosphor was determined to be 0.20 eV. Copyright © 2011 John Wiley & Sons, Ltd.     

Role of tfdC(I)D(I)E(I)F(I) and tfdD(II)C(II)E(II)F(II) gene modules in catabolism of 3-chlorobenzoate by Ralstonia eutropha JMP134(pJP4)

The enzymes chlorocatechol-1,2-dioxygenase, chloromuconate cycloisomerase, dienelactone hydrolase, and maleylacetate reductase allow Ralstonia eutropha JMP134(pJP4) to degrade chlorocatechols formed during growth in 2,4-dichlorophenoxyacetate or 3-chlorobenzoate (3-CB). There are two gene modules located in plasmid pJP4, tfdC(I)D(I)E(I)F(I) (module I) and tfdD(II)C(II)E(II)F(II) (module II), putatively encoding these enzymes. To assess the role of both tfd modules in the degradation of chloroaromatics, each module was cloned into the medium-copy-number plasmid vector pBBR1MCS-2 under the control of the tfdR regulatory gene. These constructs were introduced into R. eutropha JMP222 (a JMP134 derivative lacking pJP4) and Pseudomonas putida KT2442, two strains able to transform 3-CB into chlorocatechols. Specific activities in cell extracts of chlorocatechol-1,2-dioxygenase (tfdC), chloromuconate cycloisomerase (tfdD), and dienelactone hydrolase (tfdE) were 2 to 50 times higher for microorganisms containing module I compared to those containing module II. In contrast, a significantly (50-fold) higher activity of maleylacetate reductase (tfdF) was observed in cell extracts of microorganisms containing module II compared to module I. The R. eutropha JMP222 derivative containing tfdR-tfdC(I)D(I)E(I)F(I) grew four times faster in liquid cultures with 3-CB as a sole carbon and energy source than in cultures containing tfdR-tfdD(II)C(II)E(II)F(II). In the case of P. putida KT2442, only the derivative containing module I was able to grow in liquid cultures of 3-CB. These results indicate that efficient degradation of 3-CB by R. eutropha JMP134(pJP4) requires the two tfd modules such that TfdCDE is likely supplied primarily by module I, while TfdF is likely supplied by module II.     

Induction of in vitro flowering in Dendrobium Madame Thong-In (Orchidaceae) seedlings is associated with increase in endogenous N(6)-(Delta (2)-isopentenyl)-adenine (iP) and N (6)-(Delta (2)-isopentenyl)-adenosine (iPA) levels

We analysed the endogenous cytokinin levels of Dendrobium Madame Thong-In seedlings grown in vitro during vegetative and flowering-inductive periods. HPLC was used to fractionate the extracts and radioimmunoassay (RIA) was used for assay of zeatin (Z), dihydrozeatin (DZ), N(6)-(Delta(2)-isopentenyl)-adenine (iP) and their derivatives. Coconut water used in experiments was found to contain high level (>136 pmol ml(-1)) of zeatin riboside (ZR). Protocorms and seedlings cultured in medium with coconut water were found to contain 0.5-3.9 pmol g(-1) FW of the cytokinins analysed. Seedlings (1.0-1.5 cm) cultured in flowering-inductive liquid medium containing 6-benzyladenine (BA, 4.4 muM) and coconut water (CW, 15%) contained up to 200 and 133 pmol g(-1) FW of iP and iPA, respectively. These levels were significantly higher than all other cytokinins analysed in seedlings of the same stage and were about 80- to 150-folds higher than seedlings cultured in non-inductive medium. During the transitional (vegetative to reproductive) stage, the endogenous levels of iP (178 pmol g(-1) FW) and iPA (63 pmol g(-1) FW) were also significantly higher than cytokinins in the zeatine (Z) and dihydrozeatin (DZ) families in the same seedlings. Seedlings that grew on inductive medium but remained vegetative contained lower levels of iPA. The importance of the profiles of iP and its derivatives in induction of in vitro flowering of D. Madame Thong-In is discussed.     

The helix-coil transitions of poly (dA)-poly (dT) and poly (dA-dT)-poly (dA-dT)

Helix–coil transition curves are calculated for poly (dA) poly(dT) and poly (dA-dT) poly (dA-dT) using the integral equation approach of Goel and Montroll.⁵ The transitions are described by the loop entropy model with the exponent of the loop entropy factor, k, remaining an arbitrary constant. The theoretical calculations are compared with experimental transition curves of the two polymers. Results indicate that the stacking energies for these two polymers differ by about 1 kcal/mole of base pairs. Also, a fit between theory and experiment was not possible for k > 1.70.     

Biology of Bactrocera (Zeugodacus) tau (Walker) (Diptera: Tephritidae)

The biology of the fruit fly Bactrocera tau, an important horticultural pest, was studied under laboratory conditions at 25°C and 60–70% relative humidity on Cucurbita maxima. The duration of mating averaged 408.03 ± 235.93 min. After mating, the female fly had a preoviposition period of 11.7 ± 4.49 days. The oviposition rate was 9.9 ± 8.50 eggs and fecundity was 464.6 ± 67.98 eggs/female. Eggs were elliptical, smooth and shiny white, turning darker as hatching approached, and measured 1.30 ± 0.07 mm × 0.24 ± 0.04 mm. The chorion has polygonal microsculpturing and is species-specific with polygonal walls. The egg period lasts for 1.3 ± 0.41 days. The duration of the larval period is 1.2 ± 0.42, 1.7 ± 0.48 and 4.0 ± 0.94 days for first, second and third instars, respectively. Pupation occurs in the sand or soil and pupal periods are 7.0 ± 0.47 days. The life cycle from egg to adult was completed in 14.2 ± 1.69 days; the longevity of mated females and males was 130.33 ± 14.18 and 104.66 ± 31.21 days, respectively. At least two to three generations were observed from June 2008 to June 2009.     

Spectroscopic investigations of Er(3+) :CdO-Bi(2) O(3) -B(2) O(3) glasses

This article reports on the optical properties of Er³⁺ ions doped CdO–Bi₂O₃–B₂O₃ (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd–Ofelt theory, the intensity parameters Ω_λ (λ = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er³⁺:CdBiB glasses. The concentration quenching and energy transfer from Yb³⁺–Er³⁺ were explained. The stimulated emission cross‐section, full width at half maximum (FWHM) and FWHM × values are also calculated for all the Er³⁺:CdBiB glasses. Copyright © 2011 John Wiley & Sons, Ltd.     

Cationic (tripyrrinato)palladium(II) complexes

The formation of cationic palladium(II)complexes [TrpyPd^II]⁺X⁻ by salt metathesis of the respective trifluoroacetates with different salts of weakly coordinating anions X⁻ was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear complexes are observed depending on the nature of the anion X⁻ and the solvent. The mononuclear cations, which are only formed with X = BAr^F, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of Pd^II. When treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base adducts [TrpyPd^IIL]⁺ with L = CH₃NC, tBuNH₂, PMe₃, PEt₃ and PiPr₃ and [TrpyPd^IIL₂]⁺ with L = PMe₃ were prepared from the mononuclear cations [TrpyPd^II]⁺BAr^F−. From structural studies it becomes apparent, that the formation of stable five coordinate Pd^II species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the strain, which is induced on the TrpyPd^II unit.