Lipids of nuclear fractions from neurons and glia of rat neocortex under conditions of artificial hypobiosis

Lipid contents were studied in tissue and nuclei isolated from neurons and glia of neocortex of rats under conditions of normothermia and in the state of artificial hypobiosis caused by hypothermia-hypoxia-hypercapnia. Compared to the neocortex tissue, both nuclear fractions were fivefold impoverished in phospholipids and cholesterol and strongly enriched with mono- and diglycerides and fatty acids. The nuclear fractions from neurons and glia contained similar amounts of phospholipids, and only the cardiolipin content in the neuronal nuclei was lower than in the glial nuclei. The state of artificial hypobiosis in rats led to an increase in the cholesterol/phospholipids ratio (mol/mol) in the nuclei from the neurons and glia; amounts of cholesterol and sphingomyelin in the nuclei from the glia were increased. The increases in the cholesterol and sphingomyelin contents and in the cholesterol/phospholipids ratio suggest an involvement of lipid-dependent signaling systems of the nuclei in the functional response of mammalian neocortex cells to artificial hypobiosis.     

Numerical 1D PIC-simulations of ion acceleration during laser-plasma interaction: Optimization of a two-component multilayered target structure

Ion beam acceleration is simulated using a one-dimensional 1D2P PIC code. The dependences of the maximum energy and width of the energy spectrum of the generated ion beams on the duration and intensity of laser radiation, as well as on the target parameters (thickness and number of layers, types and densities of atoms), are investigated. The optimal target configuration at which the energy of the accelerated ions is maximum (5–160 MeV for intensities of 5 × 10^{18 −5} × 10²⁰ W/cm²) is found. The optimal target configuration is shown to depend on the intensity and be independent of the laser pulse duration.     

Analysis of mitochondrial DNA from somatic hybrid cell lines of Saccharum officinarum (sugarcane) and Pennisetum americanum (pearl millet)

Mitochondrial DNA (mtDNA) from cell suspension cultures of two intergeneric somatic hybrids of Pennisetum americanum (pearl millet) + Saccharum officinarum (sugarcane) was examined by restriction endonuclease digestion and hybridization with sorghum mtDNA cosmids. The mtDNA of one somatic hybrid was indistinguishable from that of pearl millet, while the second exhibited a combination of parental mtDNAs, suggesting mitochondrial fusion. Several novel, possibly recombinant, mtDNA restriction fragments were detected in this hybrid, which may have resulted from intergenmic recombination.Florida Agriculture Experiment Station Journal Series No: 8090.     

Physicochemical properties of multicomponent poly(hydroxyalkanoates)

The properties of new five-component poly(hydroxyalkanoates) (PHA) formed by short-and medium-chain monomers synthesized by the bacterium Wautersia eutropha B5786 were studied by X-ray diffraction, IR spectroscopy, differential thermal analysis, and viscometry. The degree of crystallinity of PHA decreased from 72 to 57% as the molar fraction of hydroxyhexanoate increased from 2.5 to 18.0 mol%. The melting temperature (T _m) and decomposition temperature (T _d) of the multicomponent PHA are lower than those for poly(hydroxybutyrate), whose T _m and T _d are 168–170 and 260–265°C, respectively. Both parameters of the multicomponent PHA decrease to 156 and 252°C, respectively, as the hydroxyhexanoate mole fraction is raised. The effect of hydroxyhexanoate on the physicochemical properties of the PHA is similar to that of hydroxyvalerate observed previously.     

Special traits of tissue lipids of whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> living in water bodies with different anthropogenous load

The impact of water pollution on the content of lipid components of the liver and eggs of whitefish Coregonus lavaretus is investigated. The content of triacylglycerols (TAG), sphingomyelin (SPM), phosphatidylinositol (PI), and phosphatidylserine (PS) is higher in the liver of whitefish from polluted waters being a part of adaptogenous reactions (modification of permeability of biomembranes, of activity of membrane enzymes, etc.) providing a possibility of the survival of fish under unfavorable ecological factors. The lipid spectra of whitefish gonads are more stable in comparison with the liver. This may be related to protection of the reproductive system from external influences.     

Use of algae in the study of essential cell processes

Maintenance of genomic stability is of crucial importance for all living organisms. It is no surprise that during evolution, a series of highly selective and efficient systems to detect DNA damage and control its repair have evolved. To this end, signal transduction pathways are involved in pausing the cell division cycle to provide time for repair, and ultimately releasing the cell cycle from arrest. Genetic components of the damage and replication checkpoints have been identified and a working model is beginning to emerge. This area of biological inquiry has received a great deal of attention in the past decade with the realization that the underlying regulatory mechanisms controlling the cell cycle are conserved throughout eukaryotic evolution. Many of the key players in this response have structural and functional counterparts in species as diverse as yeast and human. In recent years attention has also been paid to the plant kingdom suggesting that checkpoint controls have been highly conserved during evolution. The unicellular green alga Chlamydomonas reinhardtii is a suitable model organism for the study of basic cellular processes including cell cycle regulation and DNA repair. To investigate how algal cells accomplish these tasks, we have isolated mutants in the recognition and repair of DNA damage or in the response to DNA damage. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.     

Lipid status of fingerlings of the Atlantic salmon <Emphasis Type="Italic">Salmo salar</Emphasis> from different microbiotopes of the Varzuga River

Mechanisms of formation of phenotypic groups of fingerlings of the Atlantic salmon are investigated, related to diversity of embryos and subsequent start possibilities of dispersion of larvae to microbiotopes differing in their life conditions. The fingerlings of salmon, which after hatching and dissolution of the yolk sac moved from the mainstream of the Varzuga River to mouths of its tributaries, had an increased level of triacylglycerols and a higher growth rate than the juveniles remaining in the coastal zone of the river. The revealed differences between the compared groups of fingerlings by the spectrum of stock and structural lipids are mainly connected with distinctions of feeding of juveniles of the same age. The found stable differences by lipid spectra in fingerlings of salmon from the investigated biotopes of the Varzuga in July, August, and October are considered as biochemical prerequisites of the origin of different phenotypic groups of juveniles. Subdivision of fingerlings into phenotypic groups may further on influence the oncoming of the smoltification time of juveniles at the age 2+, 3+, and 4+. Accordingly, this is reflected in formation of the complex age structure (by the number of years spent in the river and in the sea) of the Varzuga population of Atlantic salmon.     

抗肿瘤药阿霉素诱导Wnt通路抑制因子的表达

研究抗肿瘤药阿霉素对Wnt通路抑制因子FrpHE(frizzled-related protein)和DKK-1(Dickkopf-1)表达的作用.将抗肿瘤药阿霉素加入到人肝癌HepG2(HepG2,含野生型p53;Hep3B,p53缺失)、人大肠癌(Lovo,含野生型p53)和人神经胶质瘤细胞(U251,p53突变)细胞株中.以RT-PCR技术检测阿霉素对Wnt通路抑制因子FrpHE和DKK-1的表达调节作用,以流式细胞术检测在肿瘤细胞中Wnt通路的关键调节因子β-catenin的表达.在加入阿霉素24h后FrpHEmRNA表达水平在人肝癌细胞(HepG2,含野生型p53;Hep3B,p53缺失)中与对照组相比表达水平显著增加.在人大肠癌细胞(Lovo,含野生型p53)和人神经胶质瘤细胞(U251,p53突变型)细胞中,未见FrpHE mRNA表达.DKK-1mRNA表达水平在人肝癌细胞(HepG2,含野生型p53;Hep3B,p53缺失)、人大肠癌细胞(Lovo,含野生型p53)和人神经胶质瘤细胞(U251,p53突变型)中与对照组相比表达水平显著增加.β-catenin的阳性细胞百分比强度和平均荧光量强度与对照组相比,表达水平降低.提示化疗药阿霉素能明显诱导抑制剂FrpHEmRNA和DKK-1mRNA的表达.     

拉萨河谷上段江孜沙棘Hippophea gyantsensis(Rousi)Lian种群的海拔梯度性变异

江孜沙棘[Hippophea gyantsensis(Rousi)Lian]是青藏高原特有的一种广生态幅的小乔木,在拉萨河谷地区的海拔3500～4200 m范围内均有分布.前人工作多集中在江孜沙棘果实的开发利用方面,对其基础生态学研究较少.本研究旨在探讨江孜沙棘沿海拔梯度的群落组成和表型变异的规律.为此,在拉萨河谷上段沿海拔梯度由东向西设置了4个样带:3850 m、3950 m、4050 m和4200 m,每个样带设置2至3个10 m×10 m的样方进行研究.首先,详细记录了每个样方内林下维管植物的物种组成、样方内的沙棘盖度、海拔、样方与河岸的实际距离,并用DCA [detrended correspondence analysis (去势对应分析)] 排序方法对群落及其组成物种进行排序分析.随机抽取了每个样方内的20个江孜沙棘植株个体,测定其胸径、基径、株高和叶片长度,用回归分析法分析这些变量和海拔之间的关系.研究结果表明,江孜沙棘在拉萨河谷内的主要生境分为4种类型,即:河边砾石滩地、河阶草滩、河边草甸和河边林缘, 样方排序结果主要受海拔的影响;同时,江孜沙棘植株的基径、胸径和高度都随着海拔的升高而显著减小,而叶片长度与海拔之间无显著相关.本文研究结果表明,对江孜沙棘而言,海拔所代表的综合环境因子对其分布和表型有显著的影响,而局部光照可能也是影响其表型特征的重要生态因子.