TMV载体上发生的的前体mRNA基因剪接效应

根据以往的报道,TMV基因只存在于细胞质中且不发生基因剪接,前体mRNA(Pre-mR鄄NA)的剪接只能发生在细胞核中。本研究应用RT-PCR,DNA序列测定及GUS INTRON的点突变和荧光检测等研究手段,首次发现TMV载体中GUS基因的表达和前体mRNA的剪接同时发生,证明了GUS基因在TMV载体上的剪接效应。     

An Assessment of Bacterial Populations in a Static Windrow Compost Pile

ABSTRACT

Many companies, restaurants, colleges, as well as individual homeowners, have initiated green marketing campaigns, and the composting of food and yard wastes has become commonplace. Thus, it is essential to obtain a more complete understanding of the microbial populations present in such composting processes. The focus of this study was to identify bacterial populations in a static windrow compost pile initiated on a college campus containing food trim and tree debris. Given that the compost pile was initiated during the winter it was uniquely characterized by a pre-mesophilic stage in addition to the characteristic mesophilic, thermophilic, and cooling/maturation stages. Bacteria were cultured from each stage and were identified by sequencing the 16S rRNA gene. Dominating the numbers throughout the study were bacteria within the Bacillus and Bacillus-like genera. Actinobacteria were found primarily within the pre-mesophilic stage. The mesophilic and beginning thermophilic stages displayed the most diversity, characterized by several different genera within the Proteobacteria phylum. In contrast, during the late thermophilic stage, only bacteria within the Bacillus and Brevibacillus genera were cultured. Overall, 49 different species within 27 different genera, 13 families, and 4 phyla, were identified and several genera that have not been commonly associated with household compost. Thus, this study supports a role for the continuation of culture-dependent studies to more completely define the bacterial flora involved in various composting processes.     

Development of benthic monitoring methods using photoquadrats and scuba on heterogeneous hard‐substrata: a boulder‐slope community case study

相似文献   

A metapopulation perspective for salmon and other anadromous fish

Salmonids are an important component of biodiversity, culture and economy in several regions, particularly the North Pacific Rim. Given this importance, they have been intensively studied for about a century, and the pioneering scientists recognized the critical link between population structure and conservation. Spatial structure is indeed of prime importance for salmon conservation and management. At first glance, the essence of the metapopulation concept, i.e. a population of populations, widely used on other organisms like butterflies, seems to be particularly relevant to salmon, and more generally to anadromous fish. Nevertheless, the concept is rarely used, and barely tested. Here, we present a metapopulation perspective for anadromous fish, assessing in terms of processes rather than of patterns the set of necessary conditions for metapopulation dynamics to exist. Salmon, and particularly sockeye salmon in Alaska, are used as an illustrative case study. A review of life history traits indicates that the three basic conditions are likely to be fulfilled by anadromous salmon: (i) the spawning habitat is discrete and populations are spatially separated by unsuitable habitat; (ii) some asynchrony is present in the dynamics of more or less distant populations and (iii) dispersal links populations because some salmon stray from their natal population. The implications of some peculiarities of salmon life history traits, unusual in classical metapopulations, are also discussed. Deeper understanding of the population structure of anadromous fish will be advanced by future studies on specific topics: (i) criteria must be defined for the delineation of suitable habitats that are based on features of the biotope and not on the presence of fish; (ii) the collection of long‐term data and the development of improved methods to determine age structure are essential for correctly estimating levels of asynchrony between populations and (iii) several key aspects of dispersal are still poorly understood and need to be examined in detail: the spatial and temporal scales of dispersal movements, the origin and destination populations instead of simple straying rates, and the relative reproductive success of immigrants and residents.     

Summary of results of experiments on the control of the potato tuber fungal diseases gangrene,dry rot and skin spot with various chemical substances, 1966–80

Summary Over the years 1966–80, experiments were done to compare the effectiveness of a number of fungicides and other chemical substances for the control of the post-harvest potato tuber diseases gangrene (Phoma exigua var.foveata), dry rot (Fusarium solani var.caeruleum) and skin spot (Polyscytalum (Oospora) pustulans). Generally good control of gangrene and skin spot was achieved by fumigation with 2-aminobutane (sec-butylamine). Infection levels with dry rot were too low for a definite conclusion to be reached. Thiabendazole mists and fog, and thiophanate-methyl and imazalil mists did not give as good a control of gangrene as gaseous 2-aminobutane. However a mist formulation of a mixture of thiabendazole and a salt of 2-aminobutane was as effective as gaseous 2-aminobutane against gangrene, but the formulation proved unstable and unsuitable for general use. Although none of the materials tested controlled all diseases equally well, there are several active fungicides whose use can be adapted to the particular needs and storage facilities of farmers and merchants. In some cases where fungicides did not control pathogens, failure was traced to too low a residue or poor distribution of the chemical over the tuber surface, suggesting faulty treatment or unsatisfactory methods of application.

---

Zusammenfassung Zwischen 1966 und 1980 wurden Versuche durchgeführt, um die Wirksamkeit bekannter Fungizide und einiger anderer chemischer Substanzen (haupts?chlich Organo-Halogenverbindungen) zur Bek?mpfung von Kartoffelknollenkrankheiten nach der Ernte, Phomaf?ule (Phoma exigua var.foveata), Trockenf?ule (Fusarium solani var.coeruleum) und Tüpfelfleckenkrankheit (Polyscytalum (Oospora) pustulans) zu prüfen. Tabelle 1 zeigt die Einzelheiten über die chemischen Behandlungen, die Rückst?nde ergaben, die Zeit zwischen der Ernte und Behandlung, der Applikationsmethode und der Dosis (Rückst?nde sind in Mengen pro ganzer Knolle ausgedrückt). Tabelle 2 zeigt die Ergebnisse für die Bek?mpfung von Phomaf?ule, Trockenf?ule und Tüpfelfleckenkrankheit bei verschiedenen Sorten. Lagerung und Behandlung folgten so weit als m?glich den handelsüblichen Verfahren. Phomaf?ule und Tüpfelfleckenkrankheit wurden im allgemeinen durch Begasung mit 2-Aminobutan gut bek?mpft, eine nicht ausreichende Infektion mit Trockenf?ule liess keine Aussage über die Wirksamkeit gegen diese Krankheit zu. Eintauchen in Dichlorophen war nicht sehr wirksam und Dichlorophennebel war unwirksam. Thiabendazolstaub und-spray, Thiophanatmethyl- und Imazalilstaub gaben im allgemeinen nicht so gute Bek?mpfungserfolge wie gasf?rmiges 2-Aminobutan. Das deutet darauf hin, dass die Rückst?nde zu niedrig waren, die Verbindungen zu wenig durch die Schale diffundierten, um die Pilze zu erreichen, wenn sie bereits tiefer eingedrungen waren und dass die Verteilung über die Knollenoberfl?che zu ungleichm?ssig war. Eine Mischung aus Thiabendazol und einem Salz von 2-Aminobutan war sehr wirksam gegen Phomaf?ule, sie erwies sich aber als nicht stabil und konnte für den Handel nicht hergestellt werden. Verschiedene flüchtige Organohalogenverbindungen und zwei andere wurden auf ihren Einfluss auf das Wachstum des Trockenf?ulepilzes in Reinkulturen geprüft, im Hinblick auf eine Mischung mit 2-Aminobutan. Sie wurden aber aus verschiedenen Gründen verworfen, unter anderem wegen fehlender Grundlagen über die Toxikologie einiger Substanzen. Es wird daraus geschlossen, dass, obwohl kein chemisches Produkt alle drei Krankheiten gut bek?mpfen kann, verschiedene aktive Fungizide verhanden sind, deren Gebrauch an bestimmte Notwendigkeiten und Lagerungsbedingungen bei Landwirten und H?ndlern angepasst werden kann. Es gibt betr?chtliche Hinweise, die Applikationsmethoden für St?ube zu verbessern, um h?here Rückst?nde zu erreichen und eine bessere Verteilung der Chemikalien über die Knollenoberfl?che.

---

Résumé De 1966 à 1980, des expérimentations ont été conduites pour apprécier l'efficacité d'un certain nombre de fongicides connus et d'autres substances chimiques (principalement des composés organo-halogénés) vis à vis des maladies de conservation de la pomme de terre: gangrène (Phoma exigua var. foveata), pourriture sèche (Fusarium solani var.coeruleum), et oosporiose (Polyscytalum (Oospora) pustulans). Le tableau 1 donne les détails de ces traitements chimiques: taux de résidus, période séparant la récolte du traitement, méthode d'application, dose (les données des résidus sont exprimées en poids de tubercules entiers). Le tableau 2 donne les résultats de l'efficacité vis à vis de la gangrène, de la pourriture sèche et de l'oosporiose, en utilisant différentes variétés de pommes de terre. La manutention et les traitements sont réalisés, dans la mesure du possible, dans les conditions de la pratique. En général, vis à vis de la gangrène et de l'oosporiose, une bonne efficacité était obtenue par fumigation avec le 2-aminobutane, mais l'infection était insuffisante avec la pourriture sèche pour juger de son efficacité contre cette maladie. Les trempages avec dichlorophen n'étaient pas très efficaces, et la nébulisation du dichlorophen était inefficace. Les pulvérisations et brumisations de thiabendazole, et les pulvérisations de thiophanate-méthyl et d'imazalil ne donnaient pas, en général, d'aussi bons résultats que le 2-aminobutane. Il semblerait que cela soit d? au taux de résidus trop faible, à l'impossibilité des produits de diffuser à travers l'épiderme du tubercule pour atteindre le champignon lorsqu'il est installé profondément, et à une distribution irrégulière à la surface du tubercule. Une formulation à base de thiabendazole et de sel de 2-aminobutane, appliquée en pulvérisation, était plus efficace contre la gangrène, mais la formulation était instable et n'avait p? être préparée pour une utilisation commerciale. Plusieurs organohalogénés voltatiles, et deux autres composés, étaient testés pour leur effet sur la croissance du champignon responsable de pourriture sèche, en culture pure, avec l'intention de les mélanger au 2-aminobutane; mais cela a été repoussé pour différentes raisons, en particulier pour l'insuffisance des connaissances concernant la toxicité des substances. En conclusion, bien qu'il n'y ait pas de produits chimiques qui contr?lent bien les trois maladies, il existe de nombreux fongicides actifs dont l'utilisation peut être adaptée aux besoins particuliers et ainsi faciliter la conservation chez les agriculteurs et les négociants. Un travail considérable peut être réalisé pour améliorer l'application de formulation par pulvérisation, afin d'obtenir des niveaux de résidus élevés et une meilleure distribution des produits chimiques à la surface du tubercule.

     

California Simulation of Evapotranspiration of Applied Water and Agricultural Energy Use in California

The California Simulation of Evapotranspiration of Applied Water (Cal-SIMETAW) model is a new tool developed by the California Department of Water Resources and the University of California, Davis to perform daily soil water balance and determine crop evapotranspiration (ET c ), evapotranspiration of applied water (ET aw ), and applied water (AW) for use in California water resources planning. ET aw is a seasonal estimate of the water needed to irrigate a crop assuming 100% irrigation efficiency. The model accounts for soils, crop coefficients, rooting depths, seepage, etc. that influence crop water balance. It provides spatial soil and climate information and it uses historical crop and land-use category information to provide seasonal water balance estimates by combinations of detailed analysis unit and county (DAU/County) over California. The result is a large data base of ET c and ET aw that will be used to update information in the new California Water Plan (CWP). The application uses the daily climate data, i.e., maximum (T x ) and minimum (T n ) temperature and precipitation (P cp ), which were derived from monthly USDA-NRCS PRISM data (PRISM Group 2011) and daily US National Climate Data Center (NCDC) climate station data to cover California on a 4 km×4 km change grid spacing. The application uses daily weather data to determine reference evapotranspiration (ET o ), using the Hargreaves-Samani (HS) equation (Hargreaves and Samani 1982, 1985). Because the HS equation is based on temperature only, ET o from the HS equation were compared with CIMIS ET o at the same locations using available CIMIS data to determine correction factors to estimate CIMIS ET o from the HS ET o to account for spatial climate differences. Cal-SIMETAW also employs near real-time reference evapotranspiration (ET o ) information from Spatial CIMIS, which is a model that combines weather station data and remote sensing to provide a grid of ET o information. A second database containing the available soil water holding capacity and soil depth information for all of California was also developed from the USDA-NRCS SSURGO database. The Cal-SIMETAW program also has the ability to generate daily weather data from monthly mean values for use in studying climate change scenarios and their possible impacts on water demand in the state. The key objective of this project is to improve the accuracy of water use estimates for the California Water Plan (CWP), which provides a comprehensive report on water supply, demand, and management in California. In this paper, we will discuss the model and how it determines ET aw for use in water resources planning.     

Essential role of neutrophils but not mammary alveolar macrophages in a murine model of acute Escherichia coli mastitis

Mastitis, the inflammation of the mammary gland, is an important disease affecting dairy animals worldwide. The disease is caused by mammary pathogenic bacteria and Escherichia coli are frequently implicated. Virulence factors of mammary pathogenic E. coli are only partially known and intramammary challenge with LPS elicits neutrophil recruitment in experimental bovine and murine mastitis models. We have previously shown that neutrophil recruitment in LPS-induced murine mastitis is strictly dependent on mammary alveolar macrophages. However, the relative role of alveolar macrophages and blood neutrophils in E. coli mastitis is not well defined. To this end, we selectively depleted mammary alveolar macrophages or blood neutrophils before intramammary challenge with E. coli strain P4 (ECP4). Mice depleted of alveolar macrophages prior to intramammary challenge recruited neutrophils normally and restricted bacterial growth and interstitial invasion. Importantly however, upon depletion of alveolar macrophages, ECP4 invaded the mammary alveolar epithelial cells and formed intracellular bacterial communities. In contrast, neutrophil depletion prior to intramammary infection with ECP4 was associated with unrestricted bacterial growth, tissue damage, severe sepsis and mortality. This study suggests that neutrophils but not alveolar macrophages provide essential antimicrobial defense against mammary pathogenic E. coli. Furthermore, we show here similar invasion after depletion of alveolar macrophages as in our previous studies showing that LPS/TLR4 signaling on alveolar macrophages abrogates ECP4 invasion of the mammary epithelium. Interestingly, similar ECP4 invasion and formation of intracellular communities were also observed following intramammary infection of either iNOS gene-deficient or IL-1 receptor type 1 gene-deficient mice.     

Evolution of yeast noncoding RNAs reveals an alternative mechanism for widespread intron loss

The evolutionary forces responsible for intron loss are unresolved. Whereas research has focused on protein-coding genes, here we analyze noncoding small nucleolar RNA (snoRNA) genes in which introns, rather than exons, are typically the functional elements. Within the yeast lineage exemplified by the human pathogen Candida albicans, we find--through deep RNA sequencing and genome-wide annotation of splice junctions--extreme compaction and loss of associated exons, but retention of snoRNAs within introns. In the Saccharomyces yeast lineage, however, we find it is the introns that have been lost through widespread degeneration of splicing signals. This intron loss, perhaps facilitated by innovations in snoRNA processing, is distinct from that observed in protein-coding genes with respect to both mechanism and evolutionary timing.