p53-Knockout Mice Are Protected Against the Long-Term Effects of Methamphetamine on Dopaminergic Terminals and Cell Bodies

Abstract: p53-knockout mice provide a useful model to test the role of p53 in the neurotoxic effects of drugs in vivo. To test the involvement of p53 in methamphetamine (METH)-induced toxicity, wild-type mice, as well as heterozygous and homozygous p53-knockout male mice, were administered four injections of three different doses (2.5, 5.0, and 10.0 mg/kg) of the drug given at 2-h intervals within the space of 1 day. METH caused a marked dose-dependent loss of dopamine transporters in both the striatum and the nucleus accumbens of wild-type mice killed 2 weeks after drug administration. However, this METH-induced decrease in dopamine transporters was attenuated in both homozygous and heterozygous p53-knockout mice, with homozygous animals showing significantly greater protection. The possibility for p53 involvement in METH-induced toxicity was also supported by the observation that METH caused marked increases in p53-like immunoreactivity in the striata of wild-type mice and very little change in heterozygous p53-knockout mice, whereas no p53-like immunostaining was detected in the homozygous p53-knockout mice. Further support for p53 involvement was provided by the fact that METH treatment caused significant decreases in dopamine transporter mRNA and the number of tyrosine hydroxylase-positive cells in the substantia nigra pars compacta and the ventral tegmental area of wild-type but not homozygous p53-knockout mice killed 2 weeks after cessation of METH administration. These results provide concordant evidence for a role of the tumor suppressor, p53, in the long-term deleterious effects of a drug acting on brain dopamine systems.     

Time linkages between pollination onsets of different taxa over an 11-year period in Perugia,Central Italy

Times of pollination of different taxa in the atmosphere of Perugia (Central Italy) over an 11-year period (1982–1992) were recorded and analysed by means of a 7-day volumetric Hirst-type pollen trap. For some taxa, the pollination period varied from year to year from a chronological and/or quantitative point of view. Several taxa showed a linkage in their starting dates of pollination. Knowledge of this kind of linkage allows us to build a forecasting model.     

Amino acid concentrations and selected enzyme activities in rat auditory,olfactory, and visual systems

Homogenates of specific brain regions of three sensory systems (auditory, olfactory, and visual) were prepared from pigmented Long-Evans Hooded rats and assayed for amino acid concentrations and activities of glutaminase, aspartate aminotransferase (total, cytosolic, and, by difference, mitochondrial), malate dehydrogenase, lactate dehydrogenase, and choline acetyltransferase. Comparing the quantitative distributions among regions revealed significant correlations between AAT and aspartate, between glutaminase and glutamate, between glutamate and glutamine, and between AAT plus glutaminase, or glutaminase alone, and the sum of aspartate, glutamate, and GABA, suggesting a metabolic pathway involving the synthesis of a glutamate pool as precursor to aspartate and GABA. Of the inhibitory transmitter amino acids, GABA concentrations routinely exceeded those of glycine, but glycine concentrations were relatively high in brainstem auditory structures.     

DNA sequences of the two homoeologous SLR1 genes of Brassica napus cv Westar

The DNA sequence data reported have been lodged in the Genbank, EMBL and DDBJ databases under the accession numbers Z21609 and Z26914     

Growth,nitrogen fixation and relative efficiency of nitrogenase inAlnus incana grown in different cultivation systems

Summary Three cultivation systems were compared. In one system the alders were grown hydroponically. In the two other systems the alders were planted in gravel and either given water and nutrients at intervals or the nutrient solution was continuously supplied. Alders continuously supplied with nutrients and water showed a significantly more rapid growth, higher biomass production and higher nitrogen content than did alders given nutrients and water at intervals or alders hydroponically grown. Alders continuously supplied with water and nutrients had a constant RE (relative efficiency of nitrogenase) of about 0.80 throughout the experimental period while alders supplied with water and nutrients at intervals showed a slight decrease in RE at the end of the experimental period. No strict relationship was found between RE and nitrogen content or between RE and plant productivity.     

Pollination system and its significance on isolation and hybridization in JapaneseEpimedium (Berberidaceae)

Observations on native populations of JapaneseEpimedium have revealed that two types of effective pollinators can be recognized. One of the two types, which consists of small bees (mainlyAndrena spp. andLasioglossum spp.), is characterized by nondiscriminating behavior for collecting pollen and is commonly found inEpimedium. The other type, which comprises medium sizedTetralonia nipponensis and largerBombus diversus queens as main components, showed flower-dependent foraging fidelity associated with nectar-sucking behavior.T. nipponensis with a shorter proboscis pollinated flowers with a shorter spur ofE. trifoliatobinatum and of a part ofE. s sempervirens, while the queen ofB. diversus with a longer proboscis pollinated longer spurred flowers ofE. grandiflorum andE. sempervirens. In the populations of putative hybrid-derivatives which show gradational variations of spur length, bees of the pollencollecting type pollinated any flower non-discriminately while bees of the nectar-foraging type tended to visit the flowers with spur lengths corresponding to their proboscis length. These observations suggest that the pollen-collecting bees play an important role for gene flow among theEpimedium species, and the nectar-foraging bees reinforce the isolation between the species by their selective pollination. Reproductive isolation between species ofEpimedium is discussed in relation with some practical behavior, such as flying power, of the pollinators.     

Rhodopsin and other proteins in artificial lipid membranes

Some basic aspects of incorporation of hydrophobic peptides and proteins in artificial lipid membranes are discussed. As examples valinomycin as a carrier model and gramicidin A as a channel former in lipid vesicles and in planar lipid membranes are presented.In the second part of the lecture some examples of incorporation of membrane proteins into lipid vesicles and planar lipid membranes are reported. The interaction with artificial lipid membranes of the Ca⁺ ATPase from the sarcoplasmic reticulum, of Rhodopsin, and of Bacteriorhodopsin is presented.Presented at the EMBO-Workshop on Transduction Mechanism of Photoreceptors, Jülich, Germany, October 4–8, 1976     

黑河上游灌丛建群种中国沙棘自由授粉子代父本分析和花粉流

利用SSR分子标记对中国沙棘（Hippophae rhamnoides ssp. sinensis Rousi）自由授粉的种子进行父本分析,研究其子代的父本来源和花粉散布模式。结果显示：在80%的置信水平上,193个子代中有104个个体可以确定花粉来源;在20个确定的父本中,16个为中国沙棘,4个为肋果沙棘（H.neurocarpa S.W.Liu et T.N.He）。传粉格局分析结果显示,中国沙棘有效花粉散布范围为3~71 m,平均距离为20.4 m,2株母本分别有87.23%和78.95%的有效花粉来自距其30 m的范围之内,研究结果表明中国沙棘自然种群以近距离传粉为主。此外,在黑河上游沙棘杂交带中,中国沙棘子代中的肋果沙棘花粉平均贡献率达到14.84%,表明中国沙棘与肋果沙棘存在较高的种间当代花粉流。     

Pseudomonas oleovorans as a tool in bioconversions of hydrocarbons: growth,morphology and conversion characteristics in different two-phase systems

The bioconversion of hydrocarbons by Pseudomonas oleovorans has been studied in two-phase systems. In these systems, the hydrocarbon substrate is present in sufficient amounts to form the bulk apolar phase. High cell densities (up to 20 mg dry mass per ml water phase) are reached when the apolar phase consists of n-octane, 1-octene or 1-decene. There is considerable cell damage after incubation for 50–70 h. Loss of cell viability and membrane damage as observed by freeze-fracture electron microscopy correlate with a loss of hydrocarbon oxidation, measured as the conversion of 1-octene to 1,2-epoxyoctane. The final yield of oxidized hydrocarbon in the apolar substrate phase can be increased substantially by replacing the damaged cells with freshly grown cells. Yields up to 150 mg 1,2-epoxyoctane per ml 1-octene and up to 20–25 mg 1,2-epoxyoctane per ml culture were obtained with four cycles of the cell renewal procedure. Several other substrates in addition to octene were tested in the optimized two-phase system. Of these, 1-decene was converted into (R)-1,2-epoxydecane with an optical purity of 60%, while allylbenzene was converted into chiral 1,2-epoxy-3-phenylpropane. Some of the future applications of the conversion products are discussed.