内图发展 外树形象 开创培训工作的新局面

培训管理是教育教学管理的一个组成部分。面对教育形势的巨大变化,黑龙江林业职业技术学院紧紧围绕内涵建设这一中心任务,树立新的管理理念,改革管理机制,创新管理方式,与学院的发展步调一致,步入内涵式发展、科学发展的轨道。     

Raf, a trans-acting locus, regulates the alpha-fetoprotein gene in a cell-autonomous manner

Genetic analysis provides an approach for identifying regulatory loci that govern the expression of specific genes within the context of the entire organism. Such analyses have defined two unlinked regulatory loci, termed raf and Rif, that modulate the levels of alpha-fetoprotein in liver. Of primary importance for the isolation and characterization of the raf product is to determine whether it is produced by the hepatocyte or whether it is produced by a different cell type. By means of analysis of alpha-fetoprotein expression in livers of embryo aggregation chimeras derived from mice of different raf genotypes it was possible to conclude that the product of the raf locus is expressed as a hepatocyte autonomous function that acts in trans to regulate the level of alpha-fetoprotein messenger RNA.     

One enzyme makes a fungal pathogen, but not a saprophyte, virulent on a new host plant

Certain genes of Nectria haematococca, a fingal pathogen of pea (Pisum sativum), encode pisatin demethylase (pda), a cytochrome P-450 monoxygenase that detoxifies the phytoalexin pisatin. Because pda is required by N.haematococca for pathogenicity on pea, pisatin helps defend pea against N. haematococca. The possibility that pisatin is a general defense factormicrothat is, that pda can confer pathogenicity to fungi not normally pathogenic on peamicrowas investigated. Genes encoding pda were transformed into and highly expressed in Cochliobolus heterostrophus, a fungal pathogen of maize but not of pea, and in Aspergillus nidulans, a saprophytic fungus, neither of which produces a significant amount of pda. Transformants contained at least as much pda as did wild-type N. haematococca. Recombinant C. heterostrophus was normally virulent on maize, but it also caused symptoms on pea, whereas recombinant A. nidulans did not affect pea. Thus, phytoalexins can function in nonspecific resistance of plants to microbes; saprophytes appear to lack genes for basic pathogenicity.     

Genes, genetics, and epigenetics: a correspondence

Over the past months, as this special issue took shape, the Editors of Science have monitored an exchange of seven letters initiated by three queries from M. Bacon. These queries concern the popular definitions of "genes," "genetics," and "epigenetics." Below, we reprint excerpts from these letters, referring interested readers to www.sciencemag.org/cgi/content/full/293/5532/1103/DC1 for the complete text and additional references.     

健康生活方式让生活更健康

我们经常听到有人说要坚持健康的生活方式，但是，并不是所有的人都能认真对待。尤其是年轻人，他们认为现在担心健康还为时过早。可是，最近的一项研究结果可能会让我们重新认识健康生活方式拘重要性。     

Metapopulation dynamics, abundance, and distribution in a microecosystem

The experimental fragmentation of landscapes of a natural ecosystem resulted in declines in the abundance and distribution of most species in the multispecies animal community inhabiting the landscapes and the extinction of many species. These declines caused the deterioration of the positive interspecific relation between local population abundance and distributional extent in this community. However, when patches were connected by habitat corridors, an immigration "rescue effect" arrested declines in both abundance and distribution and maintained the observed positive relation between them. These results demonstrate the importance of metapopulation dynamics and landscape connectivity for the persistence of populations in fragmented landscapes.     

Ice, quakes, and a wobble shake san francisco

The fall meeting of the American Geophysical Union (AGU) in San Francisco last month was bumped to the Moscone Center while the Civic Auditorium, its venue in past years, was being reinforced against earthquakes. And that may have been fitting, given the meeting's focus on sudden events in Earth history: the first moments of fault rupture, repeated outbursts of icebergs during the last ice age, and a shift in the seasons in the middle of this century.     

双孢蘑菇菌株双7的优质高产栽培技术

对双孢蘑菇菌株双 7的特征特性进行了分析 ,并从栽培场地、栽培季节、培养料与堆积发酵、播种、覆土、出菇管理及病害防治等方面介绍了其栽培技术     

Protein design, a minimalist approach

The question of how the amino acid sequence of a protein specifies its three-dimensional structure remains to be answered. Proteins are so large and complex that it is difficult to discern the features in their sequences that contribute to their structural stability and function. One approach to this problem is de novo design of model proteins, much simpler than their natural counterparts, yet containing sufficient information in their sequences to specify a given function (for example, folding in aqueous solution, folding in membranes, or formation of ion channels). Designed proteins provide simple model systems for understanding protein structure and function.