鲢鳙打印病豚鼠气单胞菌主要特性及系统发育学分析

对从鲢(Hypophthalmichthysmolitrix)鳙(Aristichthysnobilis)打印病病死鱼中分离到的豚鼠气单胞菌(Aeromonascaviae),进行了形态与理化特性等方面较系统的表观分类学指征鉴定。同时择代表菌株(HC960704-1)进行了16SrRNA基因的分子鉴定,测定了16SrRNA基因序列、分析了相关细菌相应序列的同源性,构建了系统发生树;HC960704-1的16SrRNA基因序列长度为1416bp(GenBank登录号:AY966888),与GenBank数据库中的气单胞菌16SrRNA基因序列的相似性在98%和100%。     

The S3- ion is stable in geological fluids at elevated temperatures and pressures

The chemical speciation of sulfur in geological fluids is a controlling factor in a number of processes on Earth. The two major chemical forms of sulfur in crustal fluids over a wide range of temperature and pressure are believed to be sulfate and sulfide; however, we use in situ Raman spectroscopy to show that the dominant stable form of sulfur in aqueous solution above 250°C and 0.5 gigapascal is the trisulfur ion S(3)(-). The large stability range of S(3)(-) enables efficient transport and concentration of sulfur and gold by geological fluids in deep metamorphic and subduction-zone settings. Furthermore, the formation of S(3)(-) requires a revision of sulfur isotope-fractionation models between sulfides and sulfates in natural fluids.     

Molecular mimicry regulates ABA signaling by SnRK2 kinases and PP2C phosphatases

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites.     

Fear of predation slows plant-litter decomposition

Aboveground consumers are believed to affect ecosystem functioning by regulating the quantity and quality of plant litter entering the soil. We uncovered a pathway whereby terrestrial predators regulate ecosystem processes via indirect control over soil community function. Grasshopper herbivores stressed by spider predators have a higher body carbon-to-nitrogen ratio than do grasshoppers raised without spiders. This change in elemental content does not slow grasshopper decomposition but perturbs belowground community function, decelerating the subsequent decomposition of plant litter. This legacy effect of predation on soil community function appears to be regulated by the amount of herbivore protein entering the soil.     

Compatibility of Beauveria bassiana with Neoseiulus barkeri for Control of Frankliniella occidentalis

The entomopathogenic fungus Beauveria bassiana(Balsamo) Vuillemin and predatory mite Neoseiulus barkeri Hughes are effective biological control agents of F rankliniella occidentalis Pergande(Thysanoptera: Thripidae), one of the most important pests of ornamentals and vegetables world-wide. Combined application of both may enhance control efficiency. T he functional response for N. barkeri on the first instar larvae of western flower thrips which were infected by B. bassiana for 1 2 and 24 h in the laboratory((25±1)°C,(70±5)% RH, L:D=16 h:8 h) was determined. The virulence of B. bassiana against the secon d instar and pupae of the thrips attacked by N. barkeri were also tested. The re sults showed that N. barkeri exhibited a Hollin g type II fu n ctional response on treated thrips. After having been treated with the fungus for 12 h and then offered to the predator, thrips were more vulnerable to be killed by N. barkeri. The second instar larvae and pupae of the thrips which had been attacked by predatory mites were m arkedly more susceptible to B. bassiana infection than normal thrips; the cu mulative corrected mortality of B. bassiana of the second instar and pupae which were attacked by N. barkeri were 57 and 94%, respectively, compared to 35 and 80% in controls on the day 8. These findings highlight the potential use of B. bas siana in combination with N. barkeri to control F. occidentalis.     

Study of electrization of powder skim milk during milk particle movement

Electrization of particles of powder materials is a widely spread phenomenon that makes a practical impact on the functional efficiency of equipment designed for producing a broad range of processed disperse products (dry milk, flour, grain, etc.). The results of electrization tests of powder skim milk particles are presented. A mathematical model of inner and outer transfer of electric charge for a single powder skim milk particle is suggested. The studies on a specialized laboratory unit have made it possible to obtain data on triboelectric charging of particles in different testing conditions.     

A Simple and Reliable Assay for Detecting Specific Nucleotide Sequences in Plants Using Optical Thin-film Biosensor Chips

Here we report the adaptation and optimization of an efficient, accurate and inexpensive assay that employs custom-designed silicon-based optical thin-film biosensor chips to detect unique transgenes in genetically modified （GM） crops and SN-P markers in model plant genomes. Briefly, aldehyde-attached sequence-specific singlestranded oligonucleotide probes are arrayed and covalently attached to a hydrazine-derivatized biosensor chip surface. Unique DNA sequences （or genes） are detected by hybridizing biotinylated PCR amplicons of the DNA sequences to probes on the chip surface. In the SN-P assay, target sequences （PCR amplicons） are hybridized in the presence of a mixture of biotinylated detector probes and a thermostable DNA ligase. Only perfect matches between the probe and target sequences, but not those with even a single nucleotide mismatch, can be covalently fixed on the chip surface. In both cases, the presence of specific target sequences is siL, nified by a color change on the chip surface （gold to blue/purple） after brief incubation with an anti-biotin IgG horseradish peroxidase （HRP） to generate a precipitable product from an HRP substrate.     

动物软组织修复资源-沙棘

伤口愈合是一种复杂的现象,是机体控制的系统对细胞进行精微同步调节的结果.然而,一系列可变因素通过多种方法来影响此过程.通常来说,机体内的各种维生素,矿物质,脂肪酸,氨基酸和其他营养物质对该过程起着直接或间接的重要影响.不仅如此,各种疾病与无数的外界因素也以不可预料的形式影响着该过程.因此,任何治疗方法都是努力控制上述因素以使机体处于最佳恢复状态.因此,当这种天然愈合过程被打断,机体的伤口就会转变为慢性,或者出现溃疡.     

Experimental infection of N'Dama cattle with trypanosomes usingGlossina palpalis gambiensis caught in the wild

Summary The transmissibility of trypanosome infection to N'Dama cattle by tsetse flies caught in the field was examined. Wild-caughtGlossina palpalis gambiensis were transferred singly into small numbered cages and allowed to feed on 14 uninfected N'Dama cattle. Following a completed feed the tsetse were dissected and infection in the proboscis, the salivary glands and the gut was recorded. Each animal was bitten by a number of tsetse ranging from five up to 64 flies. Following dissection of the tsetse flies, seven of the cattle were found to have been bitten by a single infected tsetse, five by two, while the remaining two were each fed upon by three infected tsetse. The tsetse were harbouring eitherTrypanosoma vivax or a trypanosome species belonging to theNannomonas subgenus or both species. The experimental animals were monitored daily over a period of three months for the appearance of trypanosomes in the blood and for antibodies in their sera. Other parameters such as body temperature, local skin reactions, packed red cell volume and weight changes were also measured. Trypanosomes were first detected eight days after the infective bite. Only five of the 14 cattle became infected, of which three had been exposed to a single infected tsetse fly.Trypanosoma vivax was detected in one animal,Trypanosoma congolense in two cattle and mixed infections of both species in the remaining two animals. These findings show that N'Dama cattle can become infected with trypanosomes through the bite of a single infected tsetse fly under field conditions. However, only five (possibly eight) of the 23 infected tsetse were able to transmit the parasites successfully.

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Infeccion Experimental De Ganado N'Dama Con Tripanosomas UsandoGlossina Palpalis Gambiensis Atrapadas En El Campo

Resumen Se estudió la transmisibilidad de infecciones con tripanosomas a ganado N'Dama, a través de moscas tsetse atrapadas en el campo. LasGlossina palpalis gambiensis atrapadas, fueron transferidas individualmente a jaulas numeradas, donde se alimentaron sobre 14 animales N'Dama sin infección alguna.Una vez completada una comida, las moscas se disecaron buscándose infecciones en la proboscis, glándulas salivares e intestino. Cada animal fue picado por un buen número de moscas, en un rango de cinco a 64. Seguida a la disección de las moscas tsetse, siete bovinos fueron picados por una sola mosca infectada; cinco por dos, mientras que los otros dos fueron cada uno picado por tres tsetse infectadas. Las moscas estaban infectadas conTrypanosoma vivax o con especies de tripanosomas pertenecientes al subgéneroNannomonas, o por ambas especies.Los animales fueron seguidos clínicamente día a día por un período de tres meses por la presencia de tripanosomas en la sangre y anticuerpos en el suero. Se tomaron en cuenta otros parámetros como la temperatura corporal, reacciones cutáneas locales, volumen corpuscular celular y peso corporal. Los primeros tripanosomas se detectaron ocho días después de la picadura de moscas infectadas. Solamente cinco de los 14 bovinos se infectaron, de los cuales tres, habían sido expuestos a una única tsetse infectada. Se detectóTrypanosoma vivax en un animal,T. congolense en dos bovinos más e infecciones mixtas en los otros dos.Estos hallazgos demuestran, que el ganado N'Dama puede infectarse con tripanosomiasis, seguidamente de la picadura de una sola tsetse infectada bajo condiciones de campo. Sin embargo, solamente cinco (posiblemente ocho) de las 23 tsetse infectadas, fueron capaces de transmitir el parásito exitosamente.

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Infection Experimentale De Bovins N'Dama Avec Des Trypanosomes A l'Aide DeGlossina Palpalis Gambiensis Capturees A l'Etat Sauvage

Résumé La transmissibilité de possibilité de transmission de la trypanosomose à des bovins N'Dama par des mouches tsé-tsé capturées sur le terrain a été examinée. DesGlossina palpalis gambiensis capturées à l'état sauvage ont été transférées individuellement dans de petities cages numérotées et placées pour se nourrir sur 14 bovins N'Dama indemnes.A la suite d'un repas complet, les mouches ont été disséquées et on a enregistré l'infection dans le proboscis, les glandes salivaires et l'intestin. Chaque animal a été piqué par un nombre de mouches allant de cinq à soixante quatre. A la suite de la dissection des glossines, on a trouvé que sept bovins avaient été piqués par une seule mouche infectée, cinq par deux mouches, alors que les deux derniers avaient servi à nourrir chacun trois glossines infectées. Les mouches tsé-tsé hébergeaient soitTrypanosoma vivax ou une espèce de trypanosomes appartenant au sous genreNannomonas ou par les deux espèces.Les animaux d'expérience ont été suivis quotidiennement pendant trois mois pour observer l'apparition des trypanosomes dans le sang et des anticorps dans leur sérum. D'autre paramètres tels que la température corporelle, les réactions cutanées locales, le volume erythrocytaire et les variations pondérales ont également été mesurés. Les trypanosomes ont été détectés pour la première fois huit jours après la morsure infectante. Seuls cinq des 14 bovins se sont infectés, parmi lesquels trois avaient été exposés à une seule mouche infectée. On a détéctéTrypanosoma vivax chez un animal,T. congolense chez deux bovins et des infections mixtes des deux espèces chez les deux derniers animaux infectés. Ces observations montrent que les bovins N'Dama peuvent devenir infectés par des trypanosomes par la piqure d'une unique mouche tsé-tsé infectée dans les conditions du terrain. Cependant, seulement cinq (peut-être huit) des 23 glosssines infectées ont été capables de transmettre les parasites avec succès.

     

Plasmid-encoded antibiotic resistance in Staphylococcus hyicus

A total of 33 Staphylococcus hyicus-cultures from piglets with exudative epidermatitis were analyzed for the presence of antibiotic resistance plasmids. Four small plasmids encoding resistances to chloramphenicol, macrolide-lincosamide-antibiotics, streptomycin or tetracyclines could be identified in plasmid-curing and plasmid-transformation experiments. For further characterization these plasmids were digested with restriction endonucleases. This led to the construction of a specific restriction map for each of the 4 plasmids. On the basis of their restriction maps, these 4 antibiotic resistance plasmids from "porcine" S. hyicus-cultures were compared with the respective resistance plasmids of other staphylococcal species from infections of humans and animals.