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Acyl-coenzyme A: cholesterol acyltransferase family
Yali LIU, Zhanyun GUO
Front Biol Chin. 2009, 4 (2): 129-136.
https://doi.org/10.1007/s11515-008-0096-9
The enzymes of the acyl-coenzyme A: cholesterol acyltransferase (ACAT) family are responsible for the in vivo synthesis of neutral lipids. They are potential drug targets for the intervention of atherosclerosis, hyperlipidemia, obesity, type II diabetes and even Alzheimer’s disease. ACAT family enzymes are integral endoplasmic reticulum (ER) membrane proteins and can be divided into ACAT branch and acyl-coenzyme A: diacylglycerol acyltransferase 1 (DGAT1) branch according to their substrate specificity. The ACAT branch catalyzes synthesis of cholesteryl esters using long-chain fatty acyl-coenzyme A and cholesterol as substrates, while the DGAT1 branch catalyzes synthesis of triacylglycerols using fatty acyl-coenzyme A and diacylglycerol as substrates. In this review, we mainly focus on the recent progress in the structural research of ACAT family enzymes, including their disulfide linkage, membrane topology, subunit interaction and catalysis mechanism.
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Progress in the study of algae and mosses in biological soil crusts
Jiancheng ZHAO, Yunpu ZHENG, Bingchang ZHANG, Ying CHEN, Yuanming ZHANG
Front Biol Chin. 2009, 4 (2): 143-150.
https://doi.org/10.1007/s11515-008-0104-0
Algae and mosses are not only two of the familiar communities in the process of desert vegetational succession, but also have the highest biomass in biological soil crusts. Meanwhile, being the pioneer plants, algae and mosses are involved in the establishment of biological soil crusts, which have great importance in arid environments and play a major role in desert ecosystems, such as being the indicator of the vegetation type, soil-holding, preventing erosion by water and wind, and sand fixation. This paper reviews the advances in the study of algae and mosses in arid and semi-arid areas. It mainly describes the ecological functions of algae and mosses including their influences on water cycle, circulation of substances, and community succession. In addition, the relationships between algae and mosses are discussed. Finally, some suggestions are proposed for the research orientations of algae and mosses in biological soil crusts. Ecologically, algae and mosses have significant ecological importance in arid areas, especially in those areas where environmental problems are becoming increasingly serious.
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Characteristics and functions of traditional homegardens: a review
Huyin HUAI, Alan HAMILTON
Front Biol Chin. 2009, 4 (2): 151-157.
https://doi.org/10.1007/s11515-008-0103-1
Traditional agroecosystems play an important role in the conservation of biodiversity and in sustainable development. As a typical type of traditional agroecosystem, traditional homegardens have been receiving increasing attention from scientists, especially ethnobotanists. They are considered as germplasm banks for many crops and other economic plants. They are also a key site for domestication of wild plants. Current ethnobotanical studies on homegardens focus on their structures, floristic composition, and contributions to their owners. Traditional homegardens often show complicated structures, diverse floristic compositions, multiple functions, low input (including labor and money), and ecological and socioeconomic sustainability. The characteristics and functions of traditional homegardens are closely related to many factors, such as their geographic location and the cultural backgrounds and socioeconomic conditions of their owners. Many researches on homegardens are conducted in the tropics. There are few studies on the dynamics of traditional homegardens, especially those located in temperate, arid and semi-arid zones. The dynamics of homegardens and the factors affecting these processes will be a fruitful field for future research.
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Effects of post-fire conditions on soil respiration in boreal forests with special reference to Northeast China forests
Laiye QU , Keming MA , Xiaoniu XU , Lihua WANG , Kaichiro SASA
Front Biol Chin. 2009, 4 (2): 180-186.
https://doi.org/10.1007/s11515-009-0003-z
Forest fires frequently occur in boreal forests, and their effects on forest ecosystems are often significant in terms of carbon flux related to climate changes. Soil respiration is the second largest carbon flux in boreal forests and the change in soil respiration is not negligible. Environmental factors controlling the soil respiration, for example, soil temperature, are altered by such fires. The abnormal increase in soil temperature has an important negative effect on soil microbes by reducing their activities or even by killing them directly with strong heat. On the other hand, although vegetation is directly disturbed by fires, the indirect changes in soil respiration are followed by changes in root activities and soil microbes. However, there is very limited information on soil respiration in the forests of Northeast China. This review, by combining what is known about fire influence on soil respiration in boreal forests from previous studies of post-fire effects on soil conditions, soil microbes, and forest regeneration, presents possible scenarios of the impact of anticipated post-fire changes in forest soil respiration in Northeast China.
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Changes in growth and photosynthetic characteristics of Ocimum sanctum under growth regulator treatments
Vadakkemuriyil DIVYA NAIR, Cheruth Abdul JALEEL, Ragupathi GOPI, Rajaram PANNEERSELVAM
Front Biol Chin. 2009, 4 (2): 192-199.
https://doi.org/10.1007/s11515-009-0001-1
A field experiment was conducted to investigate the effect of growth regulators on growth characteristics such as root length, shoot length, total leaf area, number of inflorescence per plant, number of flower per inflorescence, whole plant fresh weight and whole plant dry weight. Photosynthetic characteristics were also analyzed based on the same experiment. For this, various photosynthetic pigment contents such as chlorophyll, carotenoid, anthocyanin and xanthophyll content were calculated. The conventional growth regulator abscisic acid (ABA) and non-conventional growth regulator triazole compound paclobutrazol (PBZ) were used. Root length increased due to growth regulator treatment, but shoot length decreased. Leaf area was decreased due to growth regulator treatment. The number of inflorescence increased in ABA treated plants, but it was decreased in PBZ treated plants. In ABA treated plants, the number of flowers per inflorescence was increased. In PBZ treated plants the number of inflorescence was reduced. The whole plant fresh weight (FW) and dry weight (DW) were increased in ABA and PBZ treated plants. There was an increase in chlorophyll content in growth regulator treated plants compared to control, and it was more in PBZ treated plants. The carotenoid content was also increased in ABA and PBZ treated plants.
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Cadmium and copper uptake and accumulation by Sesbania rostrata seedling, a N-fixing annual plant: implications for the mechanism of heavy metal tolerance
Fuhua CHEN, Wei FANG, Zhongyi YANG, Jiangang YUAN
Front Biol Chin. 2009, 4 (2): 200-206.
https://doi.org/10.1007/s11515-009-0008-7
Sesbania rostrata, an annual tropical legume, has been found to be tolerant to heavy metals, with an unknown mechanism. It is a promising candidate species for revegetation at mine tailings. In this study, sequential extractions with five buffers and strong acids were used to extract various chemical forms of cadmium and copper in S. rostrata, with or without Cd or Cu treatments, so that the mechanisms of tolerance and detoxification could be inferred. Both metals had low transition rates from roots to the aboveground of S. rostrata. The transition ratio of Cd (4.00%) was higher than that of Cu (1.46%). The proportion of NaCl extracted Cd (mostly in protein-binding forms) increased drastically in Cd treated plants from being undetectable in untreated plants. This suggests that Cd induced biochemical processes producing protein-like phytochelatins that served as a major mechanism for the high Cd tolerance of S. rostrata. The case for Cu was quite different, indicating that the mechanism for metal tolerance in S. rostrata is metal-specific. The proportion of water-insoluble Cu (e.g. oxalate and phosphate) in roots increased significantly with Cu treatment, which partially explains the tolerance of S. rostrata to Cu. However, how S. rostrata copes with the high biotic activity of inorganic salts of Cu, which increased in all parts of the plant under Cu stress, is a question for future studies. Sesbania rostrata is among the very few N-fixing plants tolerant to heavy metals. This study provides evidence for the detoxification mechanism of metals in Sesbania rostrata.
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Study on the phenology of Chara vulgaris in Xin’an Spring, north China
Bianfang HU, Shulian XIE, Jia FENG, Meng ZHANG
Front Biol Chin. 2009, 4 (2): 207-213.
https://doi.org/10.1007/s11515-009-0007-8
The phenology of Chara vulgaris was studied. The specimens were collected four times from April 2004 to January 2005 (one sampling per season). The water temperature, pH, dissolved oxygen, specific conductance, maximum width and maximum depth were monitored at every sampling time. Eighteen main morphological characteristics of the Chara vulgaris were also observed and measured under the microscope. The results showed that all the environmental factors had different seasonal patterns and some of the morphological characteristics had significant fluctuations, indicating differences in their seasonality. At the same time, some morphological characteristics were affected by the environmental parameters to some extent and the effect was primarily exhibited in its vegetative proportions; there was little effect on the sexual reproductive characteristics. Therefore, the relatively stable sexual reproductive characteristics can be used to identify the species.
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Effects of plant growth regulators on the rapid proliferation of shoots and root induction in the Chinese traditional medicinal plant Atractylodes macrocephala
Bizeng MAO, Bowei HE, Zaiming CHEN, Bingliang WANG, Huifeng PAN, Debao LI
Front Biol Chin. 2009, 4 (2): 217-221.
https://doi.org/10.1007/s11515-009-0006-9
We developed an efficient plant regeneration protocol for rapidly propagating Atractylodes macrocephala Koidz, an important traditional Chinese medicinal plant, via shoot organogenesis. Shoot multiplication was induced on Murashige-Skoog (MS) medium supplemented with various concentrations of N-phenyl-N-1,2,3-thidiazol-5-ylurea (TDZ), 6-benzylaminopurine (BA) and α-naphthaleneacetic acid (NAA). Rooting was induced on half-strength MS medium supplemented with NAA and indolebutyric acid (IBA). The maximum mean number of shoots (5.61) was obtained from a single explant by the combined effect of 1.08 μmol/L NAA and 2.25 μmol/L TDZ. The longest roots and a minimum number of roots were produced when they were cultured in a medium without plant growth regulators. The shortest roots and the largest number of roots were observed in the medium supplemented with 2.7 μmol/L NAA.
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Development of plant communities after restoration of the Antaibao mining site, China
Xiaoyu GUO, Guilian ZHANG, Huili GONG, Kaiyun WANG, Jintun ZHANG
Front Biol Chin. 2009, 4 (2): 222-227.
https://doi.org/10.1007/s11515-008-0109-8
To investigate the dynamic changes in the artificial vegetation in an abandoned mining site, we analyzed the relationships among community types, environmental variables and community structure in the process of vegetation restoration in the Antaibao mining site, China by survey of the communities and use of biological dating methods. By means of the quantitative classification method (two-way indicator-species analysis, TWINSPAN) and the ordination technique (de-trended correspondence analysis, DCA; and de-trended canonical correspondence analysis, DCCA), the plant communities were classified into seven groups: community I, Robinia pseudoacacia + Pinus tabulaeformis - Caragana korshinskii - Agropyron cristatum; community II, Robinia pseudoacacia - Hippophae rhamnoides - Artemisia capillaries; community III, Ulmus pumila - Elaeagnus angustifolia - Artemisia capillaries;community IV, Caragana korshinskii - Agropyron cristatum + Artemisia capillaries; community V, Hippophae rhamnoides - Elymus dahuricus;community VI, Elaeagnus angustifolia + Hippophae rhamnoides - Brassica jucea;community VII, Hippophae rhamnoides + Elaeagnus angustifolia - Salsola collina. We conclude that the community types and diversity are mainly influenced by the succession time and the soil organic matter content. The forest community is more adaptable to the special inhabitation than the shrub community.
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Status of water environment pollution in the Xixi Wetland and its ecological treatment countermeasures
Wenyue CHEN, Jiemin ZHENG, Zhongquan LI, Guozheng SHEN, Yuchen LI
Front Biol Chin. 2009, 4 (2): 228-232.
https://doi.org/10.1007/s11515-009-0004-y
In this paper, the water quality of the Xixi Wetland was evaluated and the characteristics of water pollution were described according to the survey data. Based on the status of water quality and its functional requirements as an urban wetland, biological-ecological countermeasures were suggested. The experimental use of ecological technologies, such as artificial wetlands, ecological aquiculture and artificial floating island, were done in several fish ponds in the Xixi Wetland. Water monitoring results show that the quality of the treated water has improved significantly and the measures to purify the eutrophic water in the wetland have been effective.
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Seasonal effect of three desert halophytes on soil microbial functional diversity
Pinhasi-adiv YOCHEVED, Steinberger YOSEF
Front Biol Chin. 2009, 4 (2): 233-240.
https://doi.org/10.1007/s11515-009-0011-z
The objective of this study was to evaluate the effect of some plant ecophysiological adaptations on soil microbial functional diversity in a Negev Desert ecosystem. Soil samples from the upper 0-10 cm layer were collected at the study site under three species of halophyte shrubs, Zygophyllum dumosum, Hammada scoparia, and Reaumuria negevensis. These halophytes represent the most typical cover of the Negev Desert and each of them develops complex strategies that enable greater adaptation and hence, survival. The microhabitat of the shrubs showed differences in trends and magnitude of organic matter content, electrical conductivity, total soluble nitrogen, microbial functional diversity, and C compound utilization. The trends are assumed to be driven by various mechanisms of shrub adaptation in order to be able to survive the harsh desert environment. This study provides evidence that ecophysiological strategies developed by halophytes force microbial communities (from the point of view of activity, composition, and substrate utilization) to adapt to a beneficial plant-microorganism relationship.
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