HIV-1 integrase blocks infection of bacteria by single-stranded DNA and RNA bacteriophages

Expression of human immunodeficiency virus-1 integrase in Escherichia coli, at levels that had no effect on bacterial cell growth, blocked plaque formation by bacteriophages having single-stranded genomic DNA (M13) or RNA (R17, Q, PRR1). Plaque formation by phages having double-stranded genomic DNA (T4, PR4) was unaffected. Integrase also inhibited infection by the phagemid M13KO7, but it had no effect on production of phage once infection by M13KO7 was established. This result indicated that integrase affects an early stage in infection. Integrase also inhibited phage production following transfection by either single-stranded or double-stranded (replicative form) M13 DNA, it blocked M13 DNA replication, as assayed by incorporation of radioactive nucleotides into DNA, and it failed to affect bacterial pilus function. These data suggest that integrase interacts in vivo with phage nucleic acid, a conclusion supported by studies in which integrase was shown to have a DNA-binding activity in its C-terminal portion. This portion of integrase was both necessary and sufficient for interference of plaque formation by M13 in the present study. Expression of the N-terminal portion of integrase at the same level as intact integrase had little effect on phage growth, indicating that expression of foreign protein in general was not responsible for the inhibitory effect. The simple bacteriophage assay described is potentially useful for identifying integrase mutants that lack single-stranded DNA binding activity.     

Guanine nucleotide regulatory protein alterations in young Milan hypertensive strain rats

Vascular smooth muscle cell membranes from prehypertensive rats of the Milan hypertensive strain (MHS) were used to examine adenylyl cyclase activity and its regulation by guanine nucleotide regulatory proteins (G-proteins). Basal adenylyl cyclase activity was similar in MHS and Milan normontensive strain (MNS) membranes. Forsokolin (10^?4 M) produced a significantly greater stimulatory response in MHS membranes, but this was not observed with NaF (10^?2 M). Isoporterenol (10^?4 M) caused a significantly decreased stimulation of adenylyl cyclase activity in MHS membranes, while prostaglandin E₁ (10^?5 M) produced similar responses in the two strains. G_i function and GTP responses, as observed by biphasic effects of GTP on isoproterenol-stimulated membranes, were similar in both strains. The levels of G_i2α and G_qα/G₁₁α were similar in the two strains, while the levels of G_sα (44 and 42 kDa forms) and the β-subunit were significantly reduced by ～20% in MHS membranes. The α-subunit of G_i3 was dramatically reduced by ～80% in MHS membranes. The affinities of β-adrenergic receptors for the antagonist, cyanophindolol, were similar in the two strains; however, the number of β-adrenoceptors was substantially reduced in MHS membranes. These findings may be of relevance to altered vascular reactivity and transmembrane ion distribution observed in the MHS.     

A Polymerase Chain Reaction Method for Identification of Five Major Meloidogyne Species

A polymerase chain reaction (PCR) method for discriminating Meloidogyne incognita, M. arenaria, M. javanica, M. hapla, and M. chitwoodi was developed. Single juveniles were ruptured in a drop of water and added directly to a PCR reaction mixture in a microcentrifuge tube. Primer annealing sites were located in the 3'' portion of the mitochondrial gene coding for cytochrome oxidase subunit II and in the 16S rRNA gene. Following PCR amplification, fragments of three sizes were detected. The M. incognita and M. javanica reactions produced a 1.7-kb fragment; the M. arenaria reaction, a 1.1-kb fragment; and the M. hapla and M. chitwoodi reactions resulted in a 0.52-kb fragment. Digestion of the amplified product with restriction endonucleases allowed discrimination among species with identically sized amplification products. Dra I digestions of the 0.52-kb amplification product produced a characteristic three-banded pattern in M. chitwoodi, versus a two-banded pattern in M. hapla. Hinf I digestion of the 1.7-kb fragment produced a two-banded pattern in M. javanica, versus a three-banded pattern in M. incognita. Amplification and digestion of DNA from juveniles from single isolates of M. marylandi, M. naasi, and M. nataliei indicated that the diagnostic application of this primer set may extend to less frequently encountered Meloidogyne species.     

Description and SEM Observations of Meloidogyne sasseri n. sp. (Nematoda: Meloidogynidae), Parasitizing Beachgrasses

Meloidogyne sasseri n. sp. is described and illustrated from American beachgrass (Ammophila breviliffulata) originally collected from Henlopen State Park and Fenwick Island near the Maryland state line in Delaware, United States (6). Its relationship to M. graminis, M. spartinae, and M. californiensis is discussed. Primary distinctive characters of the female perineal pattern were a high to rounded arch with shoulders, widely spaced lateral lines interrupting transverse striations, a sunken vulva and anus, and coarse broken striae around the anal area. Second-stage juvenile body length was 554 μm (470-550), stylet length 14 μm (13-14.5), tail length 93 μm (83-115), tapering to a finely rounded terminus. Male stylet length 20 μm (19-21.5), spicule length 33 μm (30-36). Scanning electron microscope observations provided additional details of perineal patterns and face views of the female, male, and J2 head. Wheat, rice, oat, Ammophila sp., Panicum sp., bermudagrass, zoysiagrass and St. Augustinegrass were tested as hosts. Distribution of the species was the coasts of Delaware and Maryland. The common name "beachgrass root-knot" is proposed for M. sasseri n. sp.     

Structural characterization and physiological function of component B from Methanosarcina thermophila

The electron donor (component B) to the methyl coenzyme M methylreductase system from Methanosarcina thermophila was isolated as the 7-methyl derivative and characterized. Gas chromatography-mass spectrometry and ¹H NMR analyses identified this derivative as 7-methylthioheptanoylthreonine phosphate (CH₃-S-HTP), indicating that the original component B had the same structure (HS-HTP) as previously determined for component B from Methanobacterium thermoautotrophicum. The heterodisulfide of HS-HTP and coenzyme M (HS-CoM, 2-mercaptoethanesulfonate) was enzymatically reduced in cell extracts using electrons supplied by either H₂ or CO, confirming that HS-HTP was a functional molecule in M. thermophila.     

河北小五台山叶生丝孢菌

小五台山自然保护区位于河北省西部,为河北省第一高峰。变化悬殊的地形,使其由低谷到亚高山草甸呈明显独特的垂直植被类型分布带,山势陡峻,谷路隘险,具有华北地区罕见的森林植被及丰富的植物资源。狭谷陡峰,葳蒐险奇的地形地貌,又形成了多变的气候特征,因此蕴藏着相当丰富的真菌资源。作者1990年8月在该地区考察期间,共采集涉及林木、农作物、花卉、蔬菜等植物病害标本240份。本文报道小五台山的丝孢菌(Hyphomycetes)14属40种,其中有二个新种:(木来)木菌绒孢(Mycovellosiella coni Y.L.Guo, sp. nov.),五味子色链隔孢(Phaeoramularia schisandrae Y.L. Guo, sp. nov.)和7个中国新记录种:沼泽尾孢(Cercospora paludicola Speg.),白面子菌绒孢[Mycovellosiella ariae(Fuckel) U. Braun],薯蓣菌绒孢[Mycovellosiella dioscorae(Vassiljevski) Pons & Sutton],当归柱隔孢(Ramularia angelicae v. Hohnel),白芷柱隔孢[Ramularia heraclei(Oud.)Sacc.),莴苣柱隔孢(Ramularia lactucosa Lamb. & Fautr.)和虎耳草柱隔孢(Ramularia saxifragae Syd.)。(木来)来木菌绒孢(Mycovellosiella coni Y.L. Guo, sp. nov.)生于山茱萸科(Cornaceae)华尔特氏掠子木(Cornus walteri Wanger.)叶上。子实体生于叶背面。次生菌丝体表生。无子座。分生孢子梗1-3根从气孔伸出或作为侧枝单生于表生菌丝上,近无色,分枝,曲膝状,1-2个隔膜,5.0-50.0 × 2.5-4.0 μm。分生孢子圆柱形,无色,链生并具枝链,0-4个隔膜,6.5-45.0 × 2.0-4.0 μm。在山茱萸科尚无菌绒孢属的报道,且该菌与已报道的尾孢属菌形态特征也不同,故定为新种。五味子色链隔孢(Phaeoramularia schisandrae Y.L. Guo, sp. nov.)生于五味子科(Schisandraceae)五味子[Schisandra chinensis (Tunz.) Baill.]叶上,子实体生于叶背面。菌丝体内生。具子座。分生孢子梗紧密簇生,浅青黄褐色,不分枝,曲膝状,1-5个隔膜,20.0-75.0 (-95.0) × 4.0-5.0 μm。分生孢子圆柱形,近无色,链生并具枝链,1-4个隔膜,15.0-40.0 × 3.0-4.0 μm。五味子科既无尾孢菌属也无色链隔孢属的报道。文中为新种提供了拉丁文简介、描述和图,新记录种进行了简要描述。研究的标本保藏在中国科学院微生物研究所真菌标本室(HMAS)。     

In vivo anti inflammatory effects of the M20 IL-1 Inhibitor: I. Effects on acute inflammatory parameters

Previous studies have described an IL-1 Inhibitor produced by a myelomonocytic line developed in our laboratory (Eur J Immunol 1986; 16: 1449). This IL-1 Inhibitor was secreted by the M20 line constitutively in addition to IL-1, from which it could be separated. We have recently shown that the M20 IL-1 Inhibitor is distinct from the IL-1ra.In vitro this factor inhibited IL-1 induced proliferative responses as well as PGE₂ secretion by IL-1 induced fibroblasts. We also showed for the first time (Lymphokine Research 1988; 7(3): 268) that an IL-1 inhibitor can reduce IL-1 induced inflammatory effects. This study describes the specific effect of the M20 IL-1 Inhibitor on IL-1 induced parameters of inflammation: fever, leukocytosis and local foot pad swelling or lymph node enlargement. Purified preparations of the IL-1 Inhibitor, when injected together with IL-1, or before the IL-1, reduced fever, leukocytosis, foot pad swelling and lymph node enlargement caused by IL-1. Similar responses were obtained by injection of IL-6 or TNF, but were unaffected by the IL-1 Inhibitor, when injected together.These results indicate that the M20 IL-1 Inhibitor acts specifically on IL-1 induced responsesin vivo. The potential importance of this factor as an anti-inflammatory and immune regulatory factor, is supported by the findings of this study.Abbreviations IL-1 Interleukin 1 - IL-6 Interleukin 6 - IL-1ra Interleukin 1 receptor antagonist - TNF tumor necrosis factor     

湿度和温度对酰化紫膜LB膜M衰减的影响

用闪光动力学光谱仪测量了酰化紫膜ＬＢ膜中Ｍ衰减速率的变化。酰化紫膜ＬＢ膜的衰减无论是悬浮液状态,还是ＬＢ膜中,均比未修饰的要慢。在温度为２０℃时,酰化紫膜ＬＢ随着相对湿度的增加,Ｍ衰减加快。在相对湿度较低时（ＲＨ３４—７５％）,变化较平缓,即Ｍ的衰减加快不明显;在相对湿度较高时（ＲＨ８４—９５％）,Ｍ衰减明显加快。温度的变化则随相对湿度不同而不同。相对湿度较低时,随着温度的升高,Ｍ衰减加快;相对湿度较高时,Ｍ衰减反而减慢。酰化紫膜悬浮液的Ｍ衰减随着温度的升高而明显加快．这说明酰化紫膜ＬＢ膜中ＢＲ水合程度可能是直接影响Ｍ衰减的因素之一。     

Cloning single-stranded DNA

DNA sequence and expression analyses have greatly benefited from using M13 and pUC derived cloning vectors and their polycloning sites. A chronology of the original concepts and experiments is reviewed.