Changes in biodiversity and ecosystem function during the restoration of a tropical forest in south China

Tropical forests continue to vanish rapidly,but few long-term studies have ever examined if and how the lost forests can be restored.Based on a 45-year restoration study in south China,we found that a tropical rain forest,once completely destroyed,could not recover naturally without deliberate restoration efforts.We identified two kinds of thresholds that must be overcome with human ameliorative measures before the ecosystem was able to recover.The first threshold was imposed primarily by extreme physical conditions such as exceedingly high surface temperature and impoverished soil,while the second was characterized by a critical level of biodiversity and a landscape context that accommodates dispersal and colonization processes.Our three treatment catchments(un-restored barren land,single-species plantation,and mixed-forest stand)exhibited dramatically different changes in biodiversity and ecosystem functioning over 4 decades.The mixed forest,having the highest level of biodiversity and ecosystem functioning,possesses several major properties of tropical rain forest.These findings may have important implications for the restoration of many severely degraded or lost tropical forest ecosystems.     

Novel N-(3-carboxyl-9-benzyl-carboline-1-yl)ethylamino acids: synthesis, anti-proliferation activity and two-step-course of intercalation with calf thymus DNA

To explore the intercalating mechanism of -carbolines, four novel N-(3-carboxyl-9-benzyl-carboline-1-yl)ethylamino acids [-phenylalanine (6a), -alanine (6b), -isoleucine (6c) and -glycine (6d)] were prepared here. Their in vitro anticancer activities were examined by their anti-proliferation for 5 human carcinoma cell lines. The average IC50s against 5 human carcinoma cell lines are 53.54 microM, 118.77 microM, 147.34 microM and greater than 291.63 microM for 6a, 6b, 6c and 6d, respectively. The DNA intercalating mechanism of 6a-d was approved by the comparison of the parameters and signals of UV, CD and fluorescence spectra of calf thymus DNA (CT DNA) alone and the CT DNA/6a-d system. Using fluorescence titration based kinetic analysis a two-step-course consisting of stacking and intercalating was described and the stacking was considered as the key step to the CT DNA intercalating mechanism of 6a-d. Using fluorescence titration based thermomechanical analysis, the stacking complexes of 6a-d with CT DNA were described to be formed spontaneously and to be stabilized predominantly by their hydrophobic interactions. The intercalation itself goes very fast and only has limited contribution to their anticancer activities.     

Origin and differentiation of endemism in the flora of China

The present paper analyzed 239 endemic genera in 67 families in the flora of seed plants in China.The results showed that there are five families containing more than ten endemic genera,namely,Gesneriaceae (27),which hereafter refers to the number of endemic genera in China,Composite (20),Labiatae (12),Cruciferae (11),and Umbelliferae (10),15 families with two endemic genera,and another 30 families with only one endemic genus.Four monotypic families (Ginkgoaceae,Davidiaceae,Eucommiaceae and Acanthochlamydaceae)are the most ancient,relict and characteristic in the flora of seed plants in China.Based on integrative data of systematics,fossil history,and morphological and molecular evidence of these genera,their origin,evolution and relationships were discussed.In gymnosperms,all endemic genera are relicts of the Arctic-Tertiary flora,having earlier evolutionary history,and can be traced back to the Cretaceous or to the Jurassic and even earlier.In angiosperms,the endemic genera are mostly relicts,and are represented in all lineages in the"Eight-Class System ofClassification of Angiosperms",and endemism can be found in almost every evolutionary stage of extant angiosperms.The relict genera once occupied huge areas in the northern hemisphere in the Tertiary or the late Cretaceous,while neo-endemism mostly originated in the late Tertiary.They came from Arctic-Tertiary,Paleo-tropical-Tertiary and Tethys-Tertiary florisitic elements,and the blend of the three elements with many genera of autochthonous origin.The endemism was formed when some dispersal routes such as the North Atlantic Land Bridge,and the Bering Bridge became discontinuous during the Tertiary,as well as the climate change and glaciations in the late Tertiary and the Quaternary.Therefore,the late Tertiary is the starting point of extant endemism of the flora in China.     

Phosphorylation modulates the local conformation and self-aggregation ability of a peptide from the fourth tau microtubule-binding repeat

Phosphorylation of tau protein modulates both its physiological role and its aggregation into paired helical fragments, as observed in Alzheimer's diseased neurons. It is of fundamental importance to study paired helical fragment formation and its modulation by phosphorylation. This study focused on the fourth microtubule-binding repeat of tau, encompassing an abnormal phosphorylation site, Ser356. The aggregation propensities of this repeat peptide and its corresponding phosphorylated form were investigated using turbidity, thioflavin T fluorescence and electron microscopy. There is evidence for a conformational change in the fourth microtubule-binding repeat of tau peptide upon phosphorylation, as well as changes in aggregation activity. Although both tau peptides have the ability to aggregate, this is weaker in the phosphorylated peptide. This study reveals that both tau peptides are capable of self-aggregation and that phosphorylation at Ser356 can modulate this process.     

Microbial oil accumulation and cellulase secretion of the endophytic fungi from oleaginous plants

This research was designed to screen for strains that produce microbial oil by using straw as the substrate. One hundred and forty-one isolates of endophytic fungi were obtained from stems of seven oleaginous plant species. Sixty-nine isolates (48.9% of the total isolates) could be clearly seen having lipid bodies in their hyphae when examined with optical microscopy. Twenty-six isolates which had bigger and more oil bodies in their hyphae were selected for further research. These isolates belong to five genera includingMicrosphaeropsis, Phomopsis, Cephalosporium, Sclerocystis andNigrospora. Their oil contents ranged from 21.3 to 35.0% of dry cell weights when cultured in potato dextrose broth. When cultured on the solid-state medium composed of steam-exploded wheat straw (20% w/w), wheat bran (5%) and water (75%) they were able to produce cellulase and microbial oil with yields of 0.31≈0.69 filter paper unit and 19≈42 mg/g initial dry substrate, respectively. These results show that some endophytic fungi isolated from the oleaginous plants have the abilities of accumulating oil and producing cellulase simultaneously. They may be potential microbial oil producers by utilising straw as the substrate.     

猪细小病毒VP2蛋白主要抗原域间接ELISA方法的建立

将已获得的含猪细小病毒VP2蛋白主要抗原域编码基因VP2I重组酵母菌株在优化的条件下进行诱导表达,表达产物蛋白含量达227.6μg/ml,在此基础上以重组蛋白作为包被抗原初步建立了检测猪细小病毒抗体水平的间接ELISA方法,并对该方法进行了优化,结果表明抗原最佳包被浓度5.69μg/ml,而血清最佳稀释倍数为1∶80.阳性标准初步定为:OD待测样品＞0.5,且OD待测样品/OD阴性血清＞2.0.采用iVP2I-ELISA对猪血清样品进行检测,结果显示iVP2I-ELISA与HI试验的符合率为97.2%,与国外同类试剂盒的符合率达到91.2%.     

Effect of Water Content on Glass Transition and Protein Aggregation of Whey Protein Powders During Short-Term Storage

The objectives of this study were to investigate the moisture-induced protein aggregation of whey protein powders and to elucidate the relationship of protein stability with respect to water content and glass transition. Three whey protein powder types were studied: whey protein isolate (WPI), whey protein hydrolysates (WPH), and beta-lactoglobulin (BLG). The water sorption isotherms were determined at 23 and 45°C, and they fit the Guggenheim–Andersson–DeBoer (GAB) model well. Glass transition was determined by differential scanning calorimeter (DSC). The heat capacity changes of WPI and BLG during glass transition were small (0.1 to 0.2 Jg⁻¹ °C⁻¹), and the glass transition temperature (T _g) could not be detected for all samples. An increase in water content in the range of 7 to 16% caused a decrease in T _g from 119 down to 75°C for WPI, and a decrease from 93 to 47°C for WPH. Protein aggregation after 2 weeks’ storage was measured by the increase in insoluble aggregates and change in soluble protein fractions. For WPI and BLG, no protein aggregation was observed over the range of 0 to 85% RH, whereas for WPH, ∼50% of proteins became insoluble after storage at 23°C and 85% RH or at 45°C and ≥73% RH, caused mainly by the formation of intermolecular disulfide bonds. This suggests that, at increased water content, a decrease in the T _g of whey protein powders results in a dramatic increase in the mobility of protein molecules, leading to protein aggregation in short-term storage.     

Proteomic approach for caudal trauma-induced acute phase proteins reveals that creatine kinase is a key acute phase protein in amphioxus humoral fluid

Elevated creatine kinase (CK) in the circulation was generally regarded to be a passive release from muscle damage. We utilized proteomic methodologies to characterize amphioxus humoral fluid APPs in response to caudal trauma, and found several spots of CK alterations with up-regulation and pI shift. Its amount and enzyme activity showed a dynamic pattern of APP in humoral fluid accompanied with a reduction in enzyme activity of muscle, whereas there was no significant difference in CK amount of muscle and the other tissues and in CK enzyme activity of the other tissues between different time points of sample collection following caudal trauma. In addition, CK phosphorylation regulation during injury was not achieved by monoclonal antibodies separately against phosphothreonine, phosphotyrosine, and phosphoserine. These results suggested that the CK elevation of humoral fluid might be from muscle, being an active response to caudal trauma rather than a passive release from muscle damage. Therefore, CK ability in response to caudal trauma should be highly concerned.     

Intermolecular failure of L-type Ca2+ channel and ryanodine receptor signaling in hypertrophy

Pressure overload–induced hypertrophy is a key step leading to heart failure. The Ca²⁺-induced Ca²⁺ release (CICR) process that governs cardiac contractility is defective in hypertrophy/heart failure, but the molecular mechanisms remain elusive. To examine the intermolecular aspects of CICR during hypertrophy, we utilized loose-patch confocal imaging to visualize the signaling between a single L-type Ca²⁺ channel (LCC) and ryanodine receptors (RyRs) in aortic stenosis rat models of compensated (CHT) and decompensated (DHT) hypertrophy. We found that the LCC-RyR intermolecular coupling showed a 49% prolongation in coupling latency, a 47% decrease in chance of hit, and a 72% increase in chance of miss in DHT, demonstrating a state of “intermolecular failure.” Unexpectedly, these modifications also occurred robustly in CHT due at least partially to decreased expression of junctophilin, indicating that intermolecular failure occurs prior to cellular manifestations. As a result, cell-wide Ca²⁺ release, visualized as “Ca²⁺ spikes,” became desynchronized, which contrasted sharply with unaltered spike integrals and whole-cell Ca²⁺ transients in CHT. These data suggested that, within a certain limit, termed the “stability margin,” mild intermolecular failure does not damage the cellular integrity of excitation-contraction coupling. Only when the modification steps beyond the stability margin does global failure occur. The discovery of “hidden” intermolecular failure in CHT has important clinical implications.     

Dynamical systems for discovering protein complexes and functional modules from biological networks

Recent advances in high throughput experiments and annotations via published literature have provided a wealth of interaction maps of several biomolecular networks, including metabolic, protein-protein, and protein-DNA interaction networks. The architecture of these molecular networks reveals important principles of cellular organization and molecular functions. Analyzing such networks, i.e., discovering dense regions in the network, is an important way to identify protein complexes and functional modules. This task has been formulated as the problem of finding heavy subgraphs, the heaviest k-subgraph problem (k-HSP), which itself is NP-hard. However, any method based on the k-HSP requires the parameter k and an exact solution of k-HSP may still end up as a "spurious" heavy subgraph, thus reducing its practicability in analyzing large scale biological networks. We proposed a new formulation, called the rank-HSP, and two dynamical systems to approximate its results. In addition, a novel metric, called the standard deviation and mean ratio (SMR), is proposed for use in "spurious" heavy subgraphs to automate the discovery by setting a fixed threshold. Empirical results on both the simulated graphs and biological networks have demonstrated the efficiency and effectiveness of our proposal