Showing papers in "Science China-life Sciences in 2010"
TL;DR: The data suggests that gibel carp are under an evolutionary trajectory of diploidization, and this work highlights future perspectives about the functional divergence of duplicated genes and the sexual origin of vertebrate animals.
Abstract: A unisexual species is generally associated with polyploidy, and reproduced by a unisexual reproduction mode, such as gynogenesis, hybridogenesis or parthenogenesis. Compared with other unisexual and polyploid species, gibel carp (Carassius auratus gibelio) has a higher ploidy level of hexaploid. It has undergone several successive rounds of genome polyploidy, and experienced an additional, more recent genome duplication event. More significantly, the dual reproduction modes, including gynogenesis and sexual reproduction, have been demonstrated to coexist in the polyploid gibel carp. This article reviews the genetic basis concerning polyploidy origin, clonal diversity and dual reproduction modes, and outlines the progress in new variety breeding and gene identification involved in the reproduction and early development. The data suggests that gibel carp are under an evolutionary trajectory of diploidization. As a novel evolutionary developmental (Evo-Devo) biology model, this work highlights future perspectives about the functional divergence of duplicated genes and the sexual origin of vertebrate animals.
205 citations
TL;DR: It is shown that distant hybridization or the combination of this method with gynogenesis or androgenesis lead to different ploidy fishes with genetic variation, including fertile tetraploid hybrids, sterile triploids hybrids, fertile diploid Hybrid fish, and their derived progenies.
Abstract: Distant hybridization makes it possible to transfer the genome of one species to another, which results in changes in phenotypes and genotypes of the progenies. This study shows that distant hybridization or the combination of this method with gynogenesis or androgenesis lead to different ploidy fishes with genetic variation, including fertile tetraploid hybrids, sterile triploid hybrids, fertile diploid hybrids, fertile diploid gynogenetic fish, and their derived progenies. The formations of the different ploidy fishes depend on the genetic relationship between the parents. In this study, several types of distant hybridization, including red crucian carp (Carassius auratus red var.) (2n=100, abbreviated as RCC) (♀)×common carp (Cyprinus carpio L.) (2n=100, abbreviated as CC) (♂), and RCC (2n=100) (♀)×blunt snout bream (Megalobrama amblycephala) (2n=48, abbreviated as BSB) (♂) are described. In the distant hybridization of RCC (♀)×CC (♂), bisexual fertile F3–F18 allotetraploid hybrids (4n=200, abbreviated as 4nAT) were formed. The diploid hybrid eggs and diploid sperm generated by the females and males of 4nAT developed into diploid gynogenetic hybrids and diploid androgenetic hybrids, respectively, by gynogenesis and androgenesis, without treatment for doubling the chromosome. Improved tetraploid hybrids and improved diploid fishes with genetic variation were derived from the gynogenetic hybrid line. The improved diploid fishes included the high-body RCC and high-body goldfish. The formation of the tetraploid hybrids was related to the occurrence of unreduced gametes generated from the diploid hybrids, which involved in premeiotic endoreduplication, endomitosis, or fusion of germ cells. The sterile triploid hybrids (3n=150) were produced on a large scale by crossing the males of tetraploid hybrids with females of diploid fish (2n=100). In another distant hybridization of RCC (♀)×BSB (♂), different ploidy fishes were obtained, including diploid bisexual fertile natural gynogenetic fish (2n=100), sterile triploid hybrids (3n=124), and bisexual fertile tetraploid hybrids (4n=148). Furthermore, two kinds of pentaploid hybrids (5n=172 and 5n=198) were formed. The biological characteristics and the mechanisms of formation of the different ploidy fish were compared and discussed at the cellular and molecular level. The results indicated distant hybridization or the combination of this method with gynogenesis or androgenesis affects the formation of different ploidy fish with genetic variation.
158 citations
TL;DR: It was shown that TBARS and NO significantly increased in SCZ, while SOD activity significantly decreased in the disorganized type of SCZ patients, which demonstrated the involvement of oxidative stress in the pathophysiology of schizophrenia.
Abstract: Oxidative stress has been identified as a possible element in the neuropathological processes of schizophrenia (SCZ). Alteration of oxidative stress markers has been reported in SCZ studies, but with inconsistent results. To evaluate the risk of oxidative stress to schizophrenia, a meta-analysis was conducted, including five markers of oxidative stress [thiobarbituric reactive substances (TBARS), nitric oxide (NO), catalase (CAT), glutathione peroxidase (GP) and superoxide dismutase (SOD)] in SCZ patients versus healthy controls. This study showed that TBARS and NO significantly increased in SCZ, while SOD activity significantly decreased in the disorganized type of SCZ patients. No significant effect size was found for the activities of GP and CAT in SCZ patients ( P >0.05). Eggers regression test observed no significant publication bias across the oxidative stress markers, but found high heterogeneities in all the 5 markers. The subgroup analysis suggested that the ethnicity, sample size of patients and sample sources may contribute to the heterogeneity of the results for TBARS, NO and SOD. The result further demonstrated the involvement of oxidative stress in the pathophysiology of schizophrenia.
155 citations
TL;DR: Spatial patterns and temporal dynamics of grassland biomass were closely correlated with precipitation, while changes in soil C stocks exhibited close associations with soil moisture and soil texture, indicating that grassland ecosystems are C neutral.
Abstract: The knowledge of carbon (C) stock and its dynamics is crucial for understanding the role of grassland ecosystems in China’s terrestrial C cycle. To date, a comprehensive assessment on C balance in China’s grasslands is still lacking. By reviewing pub-lished literature, this study aims to evaluate ecosystem C stocks (both vegetation biomass and soil organic C) and their changes in China’s grasslands. Our results are summarized as follows: (1) biomass C density (C stock per area) of China’s grasslands differed greatly among previous studies, ranging from 215.8 to 348.1 g C m −2 with an average of 300.2 g C m −2 . Likewise, soil C density also varied greatly between 8.5 and 15.1 kg C m −2 . In total, ecosystem C stock in China’s grasslands was estimated at 29.1 Pg C. (2) Both the magnitude and direction of ecosystem C changes in China’s grasslands differed greatly among previous studies. According to recent reports, neither biomass nor soil C stock in China’s grasslands showed a significant change during the past 20 years, indicating that grassland ecosystems are C neutral. (3) Spatial patterns and temporal dynamics of grassland biomass were closely correlated with precipitation, while changes in soil C stocks exhibited close associations with soil moisture and soil texture. Human activities, such as livestock grazing and fencing could also affect ecosystem C dynamics in China’s grasslands.
155 citations
TL;DR: It is suggested that an ideotype root architecture for efficient N acquisition in maize should include deeper roots with high activity that are able to uptake nitrate before it moves downward into deep soil so as to increase spatial N availability in the soil.
Abstract: The use of nitrogen (N) fertilizers has contributed to the production of a food supply sufficient for both animals and humans despite some negative environmental impact. Sustaining food production by increasing N use efficiency in intensive cropping systems has become a major concern for scientists, environmental groups, and agricultural policymakers worldwide. In high-yielding maize systems the major method of N loss is nitrate leaching. In this review paper, the characteristic of nitrate movement in the soil, N uptake by maize as well as the regulation of root growth by soil N availability are discussed. We suggest that an ideotype root architecture for efficient N acquisition in maize should include (i) deeper roots with high activity that are able to uptake nitrate before it moves downward into deep soil; (ii) vigorous lateral root growth under high N input conditions so as to increase spatial N availability in the soil; and (iii) strong response of lateral root growth to localized nitrogen supply so as to utilize unevenly distributed nitrate especially under limited N conditions.
135 citations
TL;DR: The results suggest that different grassland ecosystems in China may show diverse responses to future climate changes, as the responses of grassland biomass to climate variables differed among various grassland types.
Abstract: Grassland covers approximately one-third of the area of China and plays an important role in the global terrestrial carbon (C) cycle. However, little is known about biomass C stocks and dynamics in these grasslands. During 2001–2005, we conducted five consecutive field sampling campaigns to investigate above- -and below-ground biomass for northern China’s grasslands. Using measurements obtained from 341 sampling sites, together with a NDVI (normalized difference vegetation index) time series dataset over 1982–2006, we examined changes in biomass C stock during the past 25 years. Our results showed that biomass C stock in northern China’s grasslands was estimated at 557.5 Tg C (1 Tg=1012 g), with a mean density of 39.5 g C m–2 for above-ground biomass and 244.6 g C m–2 for below-ground biomass. An increasing rate of 0.2 Tg C yr–1 has been observed over the past 25 years, but grassland biomass has not experienced a significant change since the late 1980s. Seasonal rainfall (January–July) was the dominant factor driving temporal dynamics in biomass C stock; however, the responses of grassland biomass to climate variables differed among various grassland types. Biomass in arid grasslands (i.e., desert steppe and typical steppe) was significantly associated with precipitation, while biomass in humid grasslands (i.e., alpine meadow) was positively correlated with mean January–July temperatures. These results suggest that different grassland ecosystems in China may show diverse responses to future climate changes.
121 citations
TL;DR: China’s forests are characterized by young forest age, low carbon density and a large area of planted forests, and thus have high potential to act as carbon sinks in the future, and statistical approaches and the predicted future forest area from the national forestry development plan were applied to estimate the potential of forest biomass carbon storage in China.
Abstract: China’s forests are characterized by young forest age, low carbon density and a large area of planted forests, and thus have high potential to act as carbon sinks in the future. Using China’s national forest inventory data during 1994–1998 and 1999–2003, and direct field measurements, we investigated the relationships between forest biomass density and forest age for 36 major forest types. Statistical approaches and the predicted future forest area from the national forestry development plan were applied to estimate the potential of forest biomass carbon storage in China during 2000–2050. Under an assumption of continuous natural forest growth, China’s existing forest biomass carbon (C) stock would increase from 5.86 Pg C (1 Pg=1015 g) in 1999–2003 to 10.23 Pg C in 2050, resulting in a total increase of 4.37 Pg C. Newly planted forests through afforestation and reforestation will sequestrate an additional 2.86 Pg C in biomass. Overall, China’s forests will potentially act as a carbon sink for 7.23 Pg C during the period 2000–2050, with an average carbon sink of 0.14 Pg C yr−1. This suggests that China’s forests will be a significant carbon sink in the next 50 years.
95 citations
TL;DR: The present results helped to clarify and explain such issues as the adaptability post invasion, interaction and competition between inter- and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.
Abstract: In order to ascertain the invasive mechanism and control strategy of the invasive Crofton weed, Ageratina adenophora, its ecological adaptability and population differentiation, the formation of single dominant population, displacement of native plants and sustainable management strategies were investigated. The present results helped to clarify and explain such issues as the adaptability post invasion, interaction and competition between inter- and intra-species and community resistance, thereby providing important references to researches on other invasive alien species.
84 citations
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TL;DR: The current status and future directions of understanding and manipulating fish germ cells in basic research and reproductive technology are reviewed.
Abstract: Fish, like many other animals, have two major cell lineages, namely the germline and soma. The germ-soma separation is one of the earliest events of embryonic development. Germ cells can be specifically labeled and isolated for culture and transplantation, providing tools for reproduction of endangered species in close relatives, such as surrogate production of trout in salmon. Haploid cell cultures, such as medaka haploid embryonic stem cells have recently been obtained, which are capable of mimicking sperm to produce fertile offspring, upon nuclear being directly transferred into normal eggs. Such fish originated from a mosaic oocyte that had a haploid meiotic nucleus and a transplanted haploid mitotic cell culture nucleus. The first semi-cloned fish is Holly. Here we review the current status and future directions of understanding and manipulating fish germ cells in basic research and reproductive technology.
82 citations
TL;DR: This study shows that insecticides applied for controlling bollworms have declined, which supports Chinese policy makers’ decision to not require refuges of non-Bt cotton fields and suggests that past studies may have underestimated the benefits from adopting Bt technology.
Abstract: The objective of this study is to examine whether or not the gains from reduced spraying for bollworms are being sustained more than one decade after the initial adoption in 2007. Based on farm-level data collected by the authors in 1999–2007 in 16 villages from 4 provinces, this study shows that insecticides applied for controlling bollworms have declined. This analysis supports Chinese policy makers’ decision to not require refuges of non-Bt cotton fields. It also suggests that past studies may have underestimated the benefits from adopting Bt technology.
79 citations
TL;DR: It is proposed that ITS2 is a promising candidate barcode for plant species identification because it exhibited the highest inter-specific divergence, and that this was significantly higher than the intra-specific variation in the “DNA barcoding gap” assessment and Wilcoxon two-sample tests.
Abstract: DNA barcoding is a rapidly developing frontier technology that is gaining worldwide attention. Here, seven regions (psbA-trnH, matK, ycf5, rpoC1, rbcL, ITS2, and ITS) with potential for use as DNA barcodes were tested for their ability to identify 300 samples of 192 species from 72 genera of the family Rutaceae. To evaluate each barcode’s utility for species authentication, PCR amplification efficiency, genetic divergence, and barcoding gaps were assessed. We found that the ITS2 region exhibited the highest inter-specific divergence, and that this was significantly higher than the intra-specific variation in the “DNA barcoding gap” assessment and Wilcoxon two-sample tests. The ITS2 locus had the highest identification efficiency among all tested regions. In a previous study, we found that ITS2 was able to discriminate a wide range of plant taxa, and here we confirmed that ITS2 was also able to discriminate a number of closely related species. Therefore, we propose that ITS2 is a promising candidate barcode for plant species identification.
TL;DR: This technical review looks into technical characteristics of the next-gen sequencers and provides prospective insights into their future development and applications and suggests that some of the emerging platforms are capable of supporting the $1000 genome and $100 genome goals if given a few years for technical maturation.
Abstract: As one of the most powerful tools in biomedical research, DNA sequencing not only has been improving its productivity in an exponential growth rate but also been evolving into a new layout of technological territories toward engineering and physical disciplines over the past three decades. In this technical review, we look into technical characteristics of the next-gen sequencers and provide prospective insights into their future development and applications. We envisage that some of the emerging platforms are capable of supporting the $1000 genome and $100 genome goals if given a few years for technical maturation. We also suggest that scientists from China should play an active role in this campaign that will have profound impact on both scientific research and societal healthcare systems.
TL;DR: It was beneficial for high altitude plants to compensate carbon gain and nutrient uptake under low temperature and limited nutrients by stabilizing biomass investment to photosynthetic structures and increasing the absorption surface area of fine roots.
Abstract: Plant traits and individual plant biomass allocation of 57 perennial herbaceous species, belonging to three common functional groups (forbs, grasses and sedges) at subalpine (3700 m ASL), alpine (4300 m ASL) and subnival (⩾5000 m ASL) sites were examined to test the hypothesis that at high altitudes, plants reduce the proportion of aboveground parts and allocate more biomass to belowground parts, especially storage organs, as altitude increases, so as to geminate and resist environmental stress. However, results indicate that some divergence in biomass allocation exists among organs. With increasing altitude, the mean fractions of total biomass allocated to aboveground parts decreased. The mean fractions of total biomass allocation to storage organs at the subalpine site (7%±2% S.E.) were distinct from those at the alpine (23%±6%) and subnival (21%±6%) sites, while the proportions of green leaves at all altitudes remained almost constant. At 4300 m and 5000 m, the mean fractions of flower stems decreased by 45% and 41%, respectively, while fine roots increased by 86% and 102%, respectively. Specific leaf areas and leaf areas of forbs and grasses deceased with rising elevation, while sedges showed opposite trends. For all three functional groups, leaf area ratio and leaf area root mass ratio decreased, while fine root biomass increased at higher altitudes. Biomass allocation patterns of alpine plants were characterized by a reduction in aboveground reproductive organs and enlargement of fine roots, while the proportion of leaves remained stable. It was beneficial for high altitude plants to compensate carbon gain and nutrient uptake under low temperature and limited nutrients by stabilizing biomass investment to photosynthetic structures and increasing the absorption surface area of fine roots. In contrast to forbs and grasses that had high mycorrhizal infection, sedges had higher single leaf area and more root fraction, especially fine roots.
TL;DR: The findings suggest that root biomass in grasslands tended to have been overestimated in previous reports of R/S, and did not support the hypothesis that aboveground biomass scales isometrically with belowground biomass.
Abstract: Above- and belowground biomass allocation not only influences growth of individual plants, but also influences vegetation structures and functions, and consequently impacts soil carbon input as well as terrestrial ecosystem carbon cycling. However, due to sampling difficulties, a considerable amount of uncertainty remains about the root: shoot ratio (R/S), a key parameter for models of terrestrial ecosystem carbon cycling. We investigated biomass allocation patterns across a broad spatial scale. We collected data on individual plant biomass and systematically sampled along a transect across the temperate grasslands in Inner Mongolia as well as in the alpine grasslands on the Tibetan Plateau. Our results indicated that the median of R/S for herbaceous species was 0.78 in China’s grasslands as a whole. R/S was significantly higher in temperate grasslands than in alpine grasslands (0.84 vs. 0.65). The slope of the allometric relationship between above- and belowground biomass was steeper for temperate grasslands than for alpine. Our results did not support the hypothesis that aboveground biomass scales isometrically with belowground biomass. The R/S in China’s grasslands was not significantly correlated with mean annual temperature (MAT) or mean annual precipitation (MAP). Moreover, comparisons of our results with previous findings indicated a large difference between R/S data from individual plants and communities. This might be mainly caused by the underestimation of R/S at the individual level as a result of an inevitable loss of fine roots and the overestimation of R/S in community-level surveys due to grazing and difficulties in identifying dead roots. Our findings suggest that root biomass in grasslands tended to have been overestimated in previous reports of R/S.
TL;DR: An overview of existing literature on changes in soil organic carbon (SOC) of various terrestrial ecosystems in China is provided and it is suggested that future research should focus on identifying land use changes throughout China with high spatiotemporal resolution and measuring the SOC loss and sequestration due to land use change.
Abstract: The present study provides an overview of existing literature on changes in soil organic carbon (SOC) of various terrestrial ecosystems in China. Datasets from the literature suggest that SOC stocks in forest, grassland, shrubland and cropland increased between the early 1980s and the early 2000s, amounting to (71±19) Tg·a−1. Conversion of marshland to cropland in the Sanjiang Plain of northeast China resulted in SOC loss of (6±2) Tg·a−1 during the same period. Nevertheless, large uncertainties exist in these estimates, especially for the SOC changes in the forest, shrubland and grassland. To reduce uncertainty, we suggest that future research should focus on: (i) identifying land use changes throughout China with high spatiotemporal resolution, and measuring the SOC loss and sequestration due to land use change; (ii) estimating the changes in SOC of shrubland and non-forest trees (i.e., cash, shelter and landscape trees); (iii) quantifying the impacts of grassland management on the SOC pool; (iv) evaluating carbon changes in deep soil layers; (v) projecting SOC sequestration potential; and (vi) developing carbon budget models for better estimating the changes in SOC of terrestrial ecosystems in China.
TL;DR: The aberrant activation of pDCs by self nucleic acids through TLR signaling and the ongoing production of type I IFNs do occur in some autoimmune diseases, and pDC may serve as an attractive target for therapeutic manipulations of the immune system to treat viral infectious diseases and autoimmune diseases.
Abstract: Plasmacytoid dendritic cells (pDCs) represent a unique and crucial immune cell population capable of producing large amounts of type I interferons (IFNs) in response to viral infection. The function of pDCs as the professional type I IFN-producing cells is linked to their selective expression of Toll-like receptor 7 (TLR7) and TLR9, which sense viral nucleic acids within the endosomal compartments. Type I IFNs produced by pDCs not only directly inhibit viral replication but also play an essential role in linking the innate and adaptive immune system. The aberrant activation of pDCs by self nucleic acids through TLR signaling and the ongoing production of type I IFNs do occur in some autoimmune diseases. Therefore, pDC may serve as an attractive target for therapeutic manipulations of the immune system to treat viral infectious diseases and autoimmune diseases.
TL;DR: The aim of this review is to make a comprehensive exposure of the past and present China’s major mycorrhizal research to the whole world, and to suggest potential directions for the enhancement of future mycorRhizalResearch within and/or between the Chinese and international mycor Rhizal community.
Abstract: The significance of mycorrhizas (fungal roots in 90% of land plants) in plant nutrient acquisition and growth, element biogeochemical cycling and maintaining of terrestrial ecosystem structures has been globally established for more than 120 years. Great progress in mycorrhizal research in the past 60 years (1950-2009, 1981-2009 in particular) has also been made across China, particularly in the mainland, Hong Kong and Taiwan. For instance, a total of 20 new and ~120 records of arbuscular mycorrhizal (AM) fungal species, 30 new and ~800 records of ectomycorrhizal (EM) fungal species, a dozen of new and ~100 records of orchid mycorrhizal (OM) fungal species have been isolated by morphological observation and/or molecular identification in China since the 1950s. Great accomplishment has also been made in the following area, including fungal species richness and genetic structure, relationships between species composition and plant taxa, effects of mycorrhizal fungi on plant nutrient uptake and growth, resistances to pathogens and interactions with other soil microorganisms, potential of mycorrhizal fungi in phytoremediation and/or land reclamation, alterations of enzymatic activities in mycorrhizal plants, and elevated CO2 and O3 on root colonization and species diversity. Unfortunately, the international community cannot easily appreciate almost all Chinese mycorrhizal studies since the vast majority of them have been published in Chinese and/or in China-based journals. The aim of this review is to make a comprehensive exposure of the past and present China’s major mycorrhizal research to the whole world, and then to suggest potential directions for the enhancement of future mycorrhizal research within and/or between the Chinese and international mycorrhizal community.
TL;DR: Topsoil soil organic carbon (SOC) content increase was higher in rice paddies than in dry croplands, but was higher under organic fertilization and combined organic/inorganic fertilizations than chemical fertilizations.
Abstract: Topsoil soil organic carbon (SOC) data were collected from long-term Chinese agro-ecosystem experiments presented in 76 reports with measurements over 1977 and 2006. The data set comprised 481 observations (135 rice paddies and 346 dry croplands) of SOC under different fertilization schemes at 70 experimental sites (28 rice paddies and 42 dry croplands). The data set covered 16 dominant soil types found in croplands across 23 provinces of mainland China. The fertilization schemes were grouped into six categories: N (inorganic nitrogen fertilizer only), NP (compound inorganic nitrogen and phosphorus fertilizers), NPK (compound inorganic nitrogen, phosphorus and potassium fertilizers), O (organic fertilizers only), OF (combined inorganic/organic fertilization) and Others (other unbalanced fertilizations such as P only, K only, P plus K and N plus K). Relative change in SOC content was analyzed, and rice paddies and dry croplands soils were compared. There was an overall temporal increase in topsoil SOC content, and relative annual change (RAC, g kg−1 yr−1) ranged −0.14–0.60 (0.13 on average) for dry cropland soils and −0.12–0.70 (0.19 on average) for rice paddies. SOC content increase was higher in rice paddies than in dry croplands. SOC increased across experimental sites, but was higher under organic fertilization and combined organic/inorganic fertilizations than chemical fertilizations. SOC increase was higher under balanced chemical fertilizations with compound N, P and K fertilizers than unbalanced fertilizations such as N only, N plus P, and N plus K. The effects of specific rational fertilizations on SOC increase persisted for 15 years in dry croplands and 20 years in rice paddies, although RAC values decreased generally as the experiment duration increased. Therefore, the extension of rational fertilization in China’s croplands may offer a technical option to enhance C sequestration potential and to sustain long-term crop productivity.
TL;DR: The carbon (C) and nitrogen (N) storage capabilities of Pinus densiflora in six different stand ages were investigated in Korea and the total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence, while N storage in the CWD, forest floor and mineral soil showed no significant temporal trends.
Abstract: The carbon (C) and nitrogen (N) storage capabilities of Pinus densiflora in six different stand ages (10, 27, 30, 32, 44, and 71 years old) were investigated in Korea. Thirty sample trees were destructively harvested and 12 were excavated. Samples from the above and belowground tree components, coarse woody debris (CWD), forest floor, and mineral soil (0-30 cm) were collected. Tree biomass was highest in the 71-year-old stand (202.8 t ha(-1)) and lowest in the 10-year-old stand (18.4 t ha(-1)). C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands, mainly due to higher soil C and N concentrations. Consequently, the total ecosystem C and N storage (tree+forest floor+CWD+soil) was positively correlated with stand age: increasing from a minimum in the 10 year old stand (18.8 t C ha(-1) and 1.3 t N ha(-1)) to a maximum in the 71-year-old stand (201.4 t C ha(-1) and 8.5 t N ha(-1)). The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence, while N storage in the CWD, forest floor and mineral soil showed no significant temporal trends. Our results provide important insights that will increase our understanding of C and N storage in P. densiflora stands and our ability to predict changes according to stand age in the region.
TL;DR: A statistical model is developed for estimating SOC sequestration potential in cropland and suggested that soils with high clay content and low pH in the cold, humid regions possess a larger carbon sequestration Potential than other soils.
Abstract: Agroecosystems have a critical role in the terrestrial carbon cycling process. Soil organic carbon (SOC) in cropland is of great importance for mitigating atmospheric carbon dioxide increases and for global food security. With an understanding of soil carbon saturation, we analyzed the datasets from 95 global long-term agricultural experiments distributed across a vast area spanning wide ranges of temperate, subtropical and tropical climates. We then developed a statistical model for estimating SOC sequestration potential in cropland. The model is driven by air temperature, precipitation, soil clay content and pH, and explains 58% of the variation in the observed soil carbon saturation (n=76). Model validation using independent data observed in China yielded a correlation coefficient R2 of 0.74 (n=19, P<0.001). Model sensitivity analysis suggested that soils with high clay content and low pH in the cold, humid regions possess a larger carbon sequestration potential than other soils. As a case study, we estimated the SOC sequestration potential by applying the model in Henan Province. Model estimations suggested that carbon (C) density at the saturation state would reach an average of 32 t C ha−1 in the top 0–20 cm soil depth. Using SOC density in the 1990s as a reference, cropland soils in Henan Province are expected to sequester an additional 100 Tg C in the future.
TL;DR: The global carbon cycle is one of the most important bio-geochemical cycles and it is highly likely that the atmospheric increase has resulted in global warming and sea level rise, as suggested by the Intergovernmental Panel on Climate Change (IPCC).
Abstract: The global carbon cycle is one of the most important bio-geochemical cycles. Through photosynthesis, green plants absorb CO2 from the atmosphere to produce organic matters, such as sugars, and covert solar energy into chemical energy. The organic matters are then used by all other life forms including humans. When ecosystems and atmosphere are in dynamic equilibrium, the flow of CO2 from the atmosphere into the biosphere because of photosynthesis should be equivalent to the flow of CO2 released back into the atmosphere by respiration. However, during the past century atmospheric CO2 concentration has increased substantially because of the burning of fossil fuels. It is highly likely that the atmospheric increase has resulted in global warming and sea level rise, as suggested by the Intergovernmental Panel on Climate Change (IPCC) .
TL;DR: Functional classification showed that loss-of-function of AtmyB103 impairs cell wall modification, lipid metabolic pathways, and signal transduction throughout anther development, indicating that AtMYB103 is a crucial regulator of Arabidopsis antherDevelopment.
Abstract: Previous reports indicated that AtMYB103 has an important role in tapetum development, callose dissolution, and exine formation in A. thaliana anthers. Here, we further characterized its function in anther development by expression pattern analysis, transmission electron microscopy observation of the knockout mutant, and microarray analysis of downstream genes. A total of 818 genes differentially expressed between ms188 and the wild-type were identified by global expression profiling analysis. Functional classification showed that loss-of-function of AtMYB103 impairs cell wall modification, lipid metabolic pathways, and signal transduction throughout anther development. RNA in situ hybridization confirmed that transcription factors acting downstream of AtMYB103 (At1g06280 and At1g02040) were expressed in the tapetum and microspores at later stages, suggesting that they might have important roles in microsporogenesis. These results indicated that AtMYB103 is a crucial regulator of Arabidopsis anther development.
TL;DR: The tumor necrosis factor- receptor-associated factor family consists of six mammalian members, and is shown to participate in signal transduction of a large number of receptor families including TNF receptor family (TNFR) and Toll-like receptors-interleukin-1 receptors (TLR-IL-1R) family.
Abstract: The tumor necrosis factor (TNF) receptor-associated factor (TRAF) family consists of six mammalian members, and is shown to participate in signal transduction of a large number of receptor families including TNF receptor family (TNFR) and Toll-like receptors-interleukin-1 receptors (TLR-IL-1R) family. Upon receptor activation, TRAFs are directly or indirectly recruited to the intracellular domains of these receptors. They subsequently engage other signaling proteins to activate inhibitor of κB kinase (IKK) complex, TRAF family member-associated NF-κB activator (TANK)-binding kinase 1 (TBK1) and inducible I κB kinase (IKK-i) (also known as IKKɛ), ultimately leading to activation of transcription factors such as NF-κB and interferon-regulatory factor (IRF) to induce immune and inflammatory responses.
TL;DR: Omega-3(ω-3) fatty acid desaturase transgenic pigs may improve carcass fatty acid composition and be an excellent large animal model for studying the role of ω-3 fatty acids in the prevention and treatment of coronary heart disease and cancer.
Abstract: Omega-3(ω-3) fatty acid desaturase transgenic pigs may improve carcass fatty acid composition. The use of transgenic pigs is also an excellent large animal model for studying the role of ω-3 fatty acids in the prevention and treatment of coronary heart disease and cancer. Transgenic pigs carrying synthesized fatty acid desaturase-1 gene (sFat-1) from Caenorhabditis briggsae by somatic cell nuclear transfer (SCNT) were produced for the first time in China. Porcine fetal fibroblast cells were transfected with a sFat-1 expression cassette by the liposome-mediated method. Transgenic embryos were reconstructed by nuclear transfer of positive cells into enucleated in vitro matured oocytes. A total of 1889 reconstructed embryos were transferred into 10 naturally cycling gilts. Nine early pregnancies were established, 7 of which went to term. Twenty-one piglets were born. The cloning efficiency was 1.1% (born piglets/transferred embryos). The integration of the sFat-1 gene was confirmed in 15 live cloned piglets by PCR and Southern blot except for 2 piglets. Expression of the sFat-1 gene in 12 of 13 piglets was detected with RT-PCR. The data demonstrates that an efficient system for sFat-1 transgenic cloned pigs was developed, which led to the successful production of piglets expressing the sFat-1 gene.
TL;DR: The members of TLR family selectively utilize adaptor proteins MyD88, TRIF, TIRAP and TRAM to activate overlapping but distinct signal transduction pathways which trigger production of different panels of mediators such as proinflammatory cytokines and type I interferon.
Abstract: Toll-like receptors sense invading pathogens by recognizing a wide variety of conserved pathogen-associated molecular patterns (PAMPs). The members of TLR family selectively utilize adaptor proteins MyD88, TRIF, TIRAP and TRAM to activate overlapping but distinct signal transduction pathways which trigger production of different panels of mediators such as proinflammatory cytokines and type I interferon. These mediators not only control innate immunity but also direct subsequently developed adaptive immunity. TLR activation is strictly and finely regulated at multiple levels of the signal transduction pathways.
TL;DR: There were no significant differences in the C densities of ecosystem components (except for detritus) although the six forests had varying vegetation compositions and site conditions although the differences were significant when the C pools were normalized against stand basal area.
Abstract: Quantifying forest carbon (C) storage and distribution is important for forest C cycling studies and terrestrial ecosystem mod-eling. Forest inventory and allometric approaches were used to measure C density and allocation in six representative temper-ate forests of similar stand age (42–59 years old) and growing under the same climate in northeastern China. The forests were an aspen-birch forest, a hardwood forest, a Korean pine plantation, a Dahurian larch plantation, a mixed deciduous forest, and a Mongolian oak forest. There were no significant differences in the C densities of ecosystem components (except for detritus) although the six forests had varying vegetation compositions and site conditions. However, the differences were significant when the C pools were normalized against stand basal area. The total ecosystem C density varied from 186.9 tC hm -2 to 349.2 tC hm -2 across the forests. The C densities of vegetation, detritus, and soil ranged from 86.3–122.7 tC hm -2 , 6.5–10.5 tC hm -2 , and 93.7–220.1 tC hm -2 , respectively, which accounted for 39.7%±7.1% (mean±SD), 3.3%±1.1%, and 57.0%±7.9% of the total C densities, respectively. The overstory C pool accounted for > 99% of the total vegetation C pool. The foliage bio-mass, small root (diameter -2 , 0.95–3.24 tC hm -2 , 22.0%–28.3%, and 34.5%–122.2%, respectively. The Korean pine plantation had the lowest foliage production efficiency (total biomass/foliage biomass: 22.6 g g -1 ) among the six forests, while the Dahurian larch plantation had the highest small root production efficiency (total biomass/small root biomass: 124.7 g g -1 ). The small root C density de-creased with soil depth for all forests except for the Mongolian oak forest, in which the small roots tended to be vertically dis-tributed downwards. The C density of coarse woody debris was significantly less in the two plantations than in the four natu-rally regenerated forests. The variability of C allocation patterns in a specific forest is jointly influenced by vegetation type, management history, and local water and nutrient availability. The study provides important data for developing and validating C cycling models for temperate forests.
TL;DR: This set of ESTs represents a significant proportion of the S. miltiorrhiza transcriptome, and gives preliminary insights into the gene complement, and will prove useful for uncovering secondary metabolic pathways, analyzing cDNA-array based gene expression, genetic manipulation to improve yield of desirable secondary products, and molecular marker identification.
Abstract: Salvia miltiorrhiza Bge. is a well-known traditional Chinese herb. Its roots have been formulated and used clinically for the treatment of various diseases. However, little genetic information has so far been available and this fact has become a major obstacle for molecular studies. To address this lack of genetic information, an Expressed Sequence Tag (EST) library from whole plantlets of S. miltiorrhiza was generated. From the 12959 cDNA clones that were randomly selected and subjected to single-pass sequencing from their 5′ ends, 10288 ESTs (with sizes⩾100 bp) were selected and assembled into 1288 contigs, leaving 2937 singletons, for a total of 4225 unigenes. These were analyzed using BLASTX (against protein databases), RPS-BLAST (against a conserved domain database) as well as the web-based KEGG Automatic Annotation Server for metabolic enzyme assignment. Based on the metabolic enzyme assignment, expression patterns of 14 secondary metabolic enzyme genes in different organs and under different treatments were verified using real-time PCR analysis. Additionally, a total of 122 microsatellites were identified from the ESTs, with 89 having sufficient flanking sequences for primer design. This set of ESTs represents a significant proportion of the S. miltiorrhiza transcriptome, and gives preliminary insights into the gene complement of S. miltiorrhiza. They will prove useful for uncovering secondary metabolic pathways, analyzing cDNA-array based gene expression, genetic manipulation to improve yield of desirable secondary products, and molecular marker identification.
TL;DR: Collective evidence indicates that exogenous salvianolic acid B is capable of promoting proliferation of neurospheres and differentiation towards the neuronal lineage in vitro and may act in the proliferation of NSCs and may promote NSC differentiation into neuronal cells.
Abstract: Salvianolic acid B is isolated from Salvia miltiorrhiza, the root of which is widely used as a traditional Chinese medicine to treat stroke. However, little is known about how salvianolic acid B influences growth characteristics of neural stem cells (NSCs). The purpose of the present study was to evaluate the effects of salvianolic acid B on proliferation, neurite outgrowth and differentiation of NSCs derived from the cerebral cortex of embryonic mice using MTT, flow cytometry, immunofluorescence and RT-PCR. It was found that 20 microg mL(-1) and 40 microg mL(-1) salvianolic acid B had similar effects on proliferation of NSCs, and a suitable concentration of salvianolic acid B increased the number of NSCs and their derivative neurospheres. The growth-promoting activity of salvianolic acid B was dependent on and associated with an accumulation in the G2/S-phase cell population. Salvianolic acid B also promoted the neurite outgrowth of NSCs and their differentiation into neurons. The mRNA for tau, GFAP and nestin were present in differentiating neurospheres induced by salvianolic acid B. However, high-level expression of tau mRNA and low-level expression of GFAP mRNA was detected in differentiated cells, in contrast to the control conditions. This collective evidence indicates that exogenous salvianolic acid B is capable of promoting proliferation of neurospheres and differentiation towards the neuronal lineage in vitro and may act in the proliferation of NSCs and may promote NSC differentiation into neuronal cells.
TL;DR: It is proposed that it should be necessary to do the following studies: to assess the fitness of transgenic fish in an aqueous environment with a large space and a complex structure; and to develop a controllable on-off strategy of reproduction in transgenicFish.
Abstract: It has been more than 20 years since the first batch of transgenic fish was produced. Five stable germ-line transmitted growth hormone (GH) transgenic fish lines have been generated. This paper reviews the mechanisms of integration and gene targeting of the transgene, as well as the viability, reproduction and transgenic approaches for the reproductive containment of GH-transgenic fish. Further, we propose that it should be necessary to do the following studies, in particularly, of the breeding of transgenic fish: to assess the fitness of transgenic fish in an aqueous environment with a large space and a complex structure; and to develop a controllable on-off strategy of reproduction in transgenic fish.
TL;DR: The results indicate that the main contribution to the higher substitution rates in Ascomycota does not come from mutualism, ecological conditions, sterility, metabolic rate or shorter generation time, but is possibly caused by the founder effect.
Abstract: Differences in rates of nucleotide or amino acid substitutions among major groups of organisms are repeatedly found and well documented. A growing body of evidence suggests a link between the rate of neutral molecular change within populations and the evolution of species diversity. More than 98% of terrestrial fungi belong to the phyla Ascomycota or Basidiomycota. The former is considerably richer in number of species than the latter. We obtained DNA sequences of 21 protein-coding genes from the lichenized fungus Rhizoplaca chrysoleuca and used them together with sequences from GenBank for subsequent analyses. Three datasets were used to test rate discrepancies between Ascomycota and Basidiomycota and that within Ascomycota: (i) 13 taxa including 105 protein-coding genes, (ii) nine taxa including 21 protein-coding genes, and (iii) nuclear LSU rDNA of 299 fungal species. Based on analyses of the 105 protein-coding genes and nuclear LSU rDNA datasets, we found that the evolutionary rate was higher in Ascomycota than in Basidiomycota. The differences in substitution rates between Ascomycota and Basidiomycota were significant. Within Ascomycota, the species-rich Sordariomycetes has the fastest evolutionary rate, while Leotiomycetes has the slowest. Our results indicate that the main contribution to the higher substitution rates in Ascomycota does not come from mutualism, ecological conditions, sterility, metabolic rate or shorter generation time, but is possibly caused by the founder effect. This is another example of the correlation between species number and evolutionary rates, which is consistent with the hypothesis that the founder effect is responsible for accelerated substitution rates in diverse clades.