Gametic behavior in a marine green alga, Monostroma angicava: an effect of phototaxis on mating efficiency

The role of phototactic behavior of gametes was tested experimentally in the slightly anisogamous marine green alga Monostroma angicava Kjellman, and the effect of phototaxis on mating efficiency was discovered. Both male and female gametes showed positive phototaxis in response to a white light source. In contrast, they did not respond to a red light source. Their swimming velocity did not differ between these two illuminating light sources. It was, therefore, suggested that the search ability of the gamete itself might not vary between phototactic and non-phototactic conditions. The number of zygotes formed during the mating process may be expressed as the product of the number of encounters between male and female gametes and the fraction of encounters that result in sexual fusion. In this study, with high densities of male and female gametes mixed in test tubes, almost all minor (fewer in number) gametes fused sexually within 10 min. After dilution of the gamete suspensions by half, mating efficiency in test tubes illuminated by white light from above was higher than that in dark controls. This suggests that male and female gametes gathered at the water surface through their positive phototaxis, thus increasing the rate of encounters. Mating efficiency also decreased if the test tubes were illuminated from above by white light and also shaken. Since negative phototaxis is clearly shown in planozygotes, we suggest that positive phototaxis of male and female gametes in M. angicava is an adaptive trait for increasing the rate of gametic encounters rather than for the dispersal of zygotes as previously reported for zoospores of some marine algae. Received: 12 February 1999 / Revision accepted: 24 May 1999     

Information and Communication Technology‐Enabled Low Carbon Technologies

This article outlines the subsector of the information and communication technology (ICT) industry concerned with reducing the economy's environmental impact, dubbed ICT‐enabled low carbon technologies (ICTeLCTs). The article is based on a study funded by United Kingdom (UK) Trade and Investment, a division of the UK Department for Business, Innovation and Skills. ICTeLCTs can be segmented into specialist and generalist operators. Specialists focus on one or two ICT applications to monitor or reduce environmental issues, while generalists supply products and services enabling a firm or a private household to reduce the environmental impact of its activities. The subsector can be further segmented into green ICT, energy management, building management, carbon accounting, waste management, intelligent transport systems (ITSs), and water management. The main factors driving ICTeLCTs include legislation, voluntary environmental standards, corporate social responsibility (CSR) activities, customer demand, and competitive market factors. Policy makers should continue to drive the growth of ICTeLCTs with the introduction and refinement of environmental legislation regulating energy use and markets.     

An apoA-I mimetic peptibody generates HDL-like particles and increases alpha-1 HDL subfraction in mice

The aim of this study is to investigate the capability of an apoA-I mimetic with multiple amphipathic helices to form HDL-like particles in vitro and in vivo. To generate multivalent helices and to track the peptide mimetic, we have constructed a peptibody by fusing two tandem repeats of 4F peptide to the C terminus of a murine IgG Fc fragment. The resultant peptidbody, mFc-2X4F, dose-dependently promoted cholesterol efflux in vitro, and the efflux potency was superior to monomeric 4F peptide. Like apoA-I, mFc-2X4F stabilized ABCA1 in J774A.1 and THP1 cells. The peptibody formed larger HDL particles when incubated with cultured cells compared with those by apoA-I. Interestingly, when administered to mice, mFc-2X4F increased both pre-β and α-1 HDL subfractions. The lipid-bound mFc-2X4F was mostly in the α-1 migrating subfraction. Most importantly, mFc-2X4F and apoA-I were found to coexist in the same HDL particles formed in vivo. These data suggest that the apoA-I mimetic peptibody is capable of mimicking apoA-I to generate HDL particles. The peptibody and apoA-I may work cooperatively to generate larger HDL particles in vivo, either at the cholesterol efflux stage and/or via fusion of HDL particles that were generated by the peptibody and apoA-I individually.     

Nitrogen assimilation in opaque and normal sorghum during grain development

Activity of key nitrogen assimilating enzymes was studied in developing grains of high-lysine opaque sorghum P-721 and normal sorghum CSV-5. The higher percentage of protein in opaque sorghum was mainly due to lower starch content since protein per grain was less than in CSV-5. During grain development, albufn and globulin decreased while prolafne and glutelin increased. Prolafne content in CSV-5 was higher than in opaque sorghum. Average nitrate reductase activity in flag and long leaf were similar in both the varieties. The nitrate reductase activity decreased during grain development. Glutamate dehydrogenase activity was higher during early development and lower at later stages in opaque sorghum than in CSV-5. Glutamate oxaloacetate transaminase activity was higher and glutamine synthetase lower in opaque sorghum than in CSV-5 grains during development. Glutamate synthase activity was higher in opaque sorghum up to day 20 and lower thereafter than in CSV-5. It is suggested that reduced activities of glutamine synthetase as well as glutamate synthase in opaque sorghum as compared to CSV-5 during later stages of development may restrict protein accumulation in the former.     

谷胱甘肽的测定方法进展

谷胱甘肽参与动植物体内的各种代谢活动,起着重要的作用。谷胱甘肽的测定方法有多种,如碘量法、纸层析法、高效液相色谱法等,但目前为止还没有一种快速、简便、准确、经济的方法。本文就谷胱甘肽的测定方法进展进行了简要概述。     

A comparison of the wood anatomy of 11 species from two cerrado habitats (cerrado s.s. and adjacent gallery forest)

A comparative study of the secondary xylem (wood) anatomy of 11 species (38 specimens) occurring in cerrado s.s. and the adjacent gallery forest (both cerrado s.l. habitat) was made with the aim of identifying the anatomical characteristics of ecological value and correlating them with the environmental conditions. The anatomical features that vary, in general, between the two habitats are: growth ring distinctness (well or poorly defined); tyloses and deposits (more abundant in cerrado specimens); gelatinous fibres (more evident in cerrado specimens and in different patterns between habitats); variation in paratracheal and banded parenchyma (more abundant in cerrado); and more cells per parenchyma strand in cerrado. In general, gallery forest specimens have wider vessels, fewer vessels per square millimetre and larger intervessel pits, indicating more efficient water conduction, whereas cerrado s.s. specimens are the opposite, with low vulnerability and mesomorphy indices, demonstrating greater safety under conditions of water stress. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, ?? , ??–??.     

Defense peptides from barnyard grass (Echinochloa crusgalli L.) seeds

A number of defense polypeptides from latent seeds of weed cereal barnyard grass (Echinochloa crusgalli L.) has been isolated and characterized using an acidic extraction and high performance liquid chromatography methods in combination with MALDI-TOF mass spectrometry and Edman sequencing. Members of three antimicrobial peptide families and two protease inhibitor families were found to be localized in barnyard grass seeds. Their biological activity concerning to Gram-Positive and Gram-Negative phytopathogenic bacteria, as well as oomycete Phytophthora infestans, has been investigated. Diversity of barnyard grass defense peptides is a significant factor that provides a resistance of E. crusgalli seeds to germination and latent phases.     

The first potassium channel toxin from the venom of the Iranian scorpion Odonthobuthus doriae

The very first member of K(+) channels toxins from the venom of the Iranian scorpion Odonthobuthus doriae (OdK1) was purified, sequenced and characterized physiologically. OdK1 has 29 amino acids, six conserved cysteines and a pI value of 4.95. Based on multiple sequence alignments, OdK1 was classified as alpha-KTx 8.5. The pharmacological effects of OdK1 were studied on six different cloned K(+) channels (vertebrate Kv1.1-Kv1.5 and Shaker IR) expressed in Xenopus laevis oocytes. Interestingly, OdK1 selectively inhibited the currents through Kv1.2 channels with an IC50 value of 183+/-3 nM but did not affect any of the other channels.     

蜡状芽孢杆菌S458-1对水产养殖系统中水质调节的作用

【目的】水产养殖过程中蜡状芽孢杆菌(Bacillus cereus)作为益生菌被广泛应用。本研究旨在深入了解分离于养殖水体中的一株蜡状芽孢杆菌S458-1对养殖水体以及养殖对象的影响,以期为菌株S458-1在水产养殖生产上的应用提供理论依据。【方法】根据控制变量法,各试验组鲫鱼养殖模式设置相同温度、盐度、溶氧和pH,利用分光光度法测定水体的水化学指标;利用试剂盒法测定鲫鱼的血清生理生化指标。【结果】添加菌株S458-1处理组(终浓度分别为10~6、10~7、10~8CFU/mL)与对照组(未加S458-1菌)相比:水体活性磷浓度显著性增加(P0.05);同时具有把NH_4~+-N和NO_2~–-N转化为NO_3~–-N的趋势,但无显著性差异(P0.05);养殖鲫鱼血清检测结果显示谷草转氨酶(GOT)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)以及丙二醛(MDA)含量均显著降低(P0.05)。【结论】蜡状芽孢杆菌S458-1具有脱氮解磷、调节水质的作用,并可增强养殖对象的生理健康状态,可作为益生菌应用于水产养殖中,具有较高的应用价值。     

Characterization of photosynthetic pathway of plant species growing in the eastern Tibetan plateau using stable carbon isotope composition

The photosynthetic pathway of plant species collected at Menyuan, Henan, and Maduo sites, east of Tibetan Plateau, China, during the growing season were studied using stable carbon isotopes in leaves. The 232 samples leaves analyzed belonged to 161 species, 30 families, and 94 genera. The δ¹³C values (from −24.6 to − 29.2 ‰) indicated that all the considered species had a photosynthetic C₃ pathway. The absence of plant species with C₄ photosynthetic pathway might be due to the extremely low air temperature characterizing the Tibetan Plateau. The average δ¹³C value was significantly (p<0.05) different between annuals and perennials at the three considered study sites. Hence the longer-lived species had greater water-use efficiency (WUE) than shorter-lived species, that is, longer-lived species are better adapted to the extreme environmental conditions of the Tibetan Plateau.