Preference factors in experimental alcoholism

Normal rats which refused 5-and 20-percent alcohol in a previous study were restricted to 5-percent and 20-percent solutions in their home cages for either 30 or 120 days. Differential preferences for alcohol solutions of up to 8-percent were established as a function of length of time animals consumed alcohol but not as a function of the particular concentration consumed prior to testing.     

Alkaloids from catecholamines in adrenal tissue: possible role in alcoholism

Epinephrine and norepinephrine condensed with acetaldehyde or with formaldehyde in dilute aqueous solution at neutral pH and room temperature to form 1,2,3,4-tetrahydroiso-quinoline alkaloids. Similar condensation reactions occurred in cow adrenal glands perfused with dilute aldehyde solutions at 37 degrees C. Biosynthesis of these alkaloids in vivo could play a role in altering an individual's behavior during and after the ingestion of alcohol.     

土壤微生物对化学农药的生态效应及其适应机制

综述了化学农药对土壤微生物生物量、土壤呼吸作用、氮素循环、土壤酶活性、土壤微生物功能多样性、DNA序列多样性以及土壤微生物群落结构的影响,并分析了土壤微生物群落适应化学农药污染的分子机制。     

The chimpanzee as an animal model for investigating alcoholism

Young chimpanzees (Pan troglodytes) will accept ethanol in quantities sufficient to produce symptoms of withdrawal when ethanol is subsequently discontinued. Mild to severe symptoms of physical dependence, including grand mal seizures, are observed when ethanol is abruptly withdrawn after 6 to 10 weeks of chronic oral intake. In addition, the rate of disappearance of ethanol in blood increased during periods of chronic ingestion, an indication of developing metabolic tolerance. These results suggest that the young chimpanzee may be a suitable model for experimental studies of alcoholism.     

植物的性别决定机制

植物性别决定具有不稳定性和多样性的特点,彻底揭示其机制难度较大,目前已经成为基因组学、染色体组学、进化遗传学和发育遗传学的研究热点。本文从性别决定基因、性染色体和激素调控三方面,以模式植物拟南芥(Arabidopsis thaliana L).、白麦瓶草(Silene latifolia L).、玉米(Zea mays L).、黄瓜(Cucumis sativus L.)和番木瓜(Carica papaya L.)等为例,概述植物性别决定机制的国内外研究进展,总结了各学科相关研究主要技术路线、试验方法以及研究中尚待解决的问题,并重点介绍了分子标记、RNA沉默、FISH、SSH、BAC文库等遗传分析技术的应用使本研究领域取得的重大突破。     

Neurokinin 1 receptor antagonism as a possible therapy for alcoholism

Alcohol dependence is a major public health challenge in need of new treatments. As alcoholism evolves, stress systems in the brain play an increasing role in motivating continued alcohol use and relapse. We investigated the role of the neurokinin 1 receptor (NK1R), a mediator of behavioral stress responses, in alcohol dependence and treatment. In preclinical studies, mice genetically deficient in NK1R showed a marked decrease in voluntary alcohol consumption and had an increased sensitivity to the sedative effects of alcohol. In a randomized controlled experimental study, we treated recently detoxified alcoholic inpatients with an NK1R antagonist (LY686017; n = 25) or placebo (n = 25). LY686017 suppressed spontaneous alcohol cravings, improved overall well-being, blunted cravings induced by a challenge procedure, and attenuated concomitant cortisol responses. Brain functional magnetic resonance imaging responses to affective stimuli likewise suggested beneficial LY686017 effects. Thus, as assessed by these surrogate markers of efficacy, NK1R antagonism warrants further investigation as a treatment in alcoholism.     

Clonal adaptive radiation in a constant environment

The evolution of new combinations of bacterial properties contributes to biodiversity and the emergence of new diseases. We investigated the capacity for bacterial divergence with a chemostat culture of Escherichia coli. A clonal population radiated into more than five phenotypic clusters within 26 days, with multiple variations in global regulation, metabolic strategies, surface properties, and nutrient permeability pathways. Most isolates belonged to a single ecotype, and neither periodic selection events nor ecological competition for a single niche prevented an adaptive radiation with a single resource. The multidirectional exploration of fitness space is an underestimated ingredient to bacterial success even in unstructured environments.     

Size-detecting mechanisms in human vision

Inspecting a pattern of alternating dark and light bars makes it difficult to see a similar pattern presented afterward. This phenomenon can be used to isolate mechanisms responsive to bars of a given width. Our results suggest that the human visual system contains several different classes of size detectors, each maximally sensitive to visual targets with sizes in a particular range.     

Transgenerational plasticity is adaptive in the wild

Plants exhibit adaptive responses to light, but it is not known whether parental plants transmit environmental cues that elicit adaptive responses in offspring. We show that offspring life history (annual versus biennial) is influenced by the maternal light environment (understory versus light gap). This transgenerational plasticity is adaptive when offspring are grown in their maternal light environment, where seeds typically disperse. Projections of population growth show that plants that are appropriately cued for their light environment through maternal effects have 3.4 times greater fitness than otherwise. Transgenerational plasticity has evolved in response to natural variation in light and provides a flexible mechanism by which sedentary organisms cope with heterogeneous environments.     

Viscosity mechanisms in accretion disks

The self-sustained turbulence that develops in magnetized accretion disks is suppressed in the weakly ionized, quiescent disks of close binary stars. Because accretion still proceeds during quiescence, another viscosity mechanism operates in these systems. An anticorrelation of the recurrence times of SU UMa dwarf novae with their mass ratio supports spiral waves or shockwaves tidally induced by the companion star as the main process responsible for accretion in the quiescent disks. Other weakly ionized gaseous disks in systems lacking a massive companion must rely on yet another transport mechanism, or they could be essentially passive.