2020年发表的全球维管植物新种

为了解世界维管植物新物种的基本信息, 明确生物多样性面临的威胁, 总结未来研究方向, 本文对2020年世界维管植物新物种的数据进行了统计分析。根据国际植物名称索引(IPNI)的记录, 截至2021年2月1日, 2020年全球发现1,747种维管植物新种, 由1,544名植物学家(264位中国植物学家, 1,280位国外植物学家)发表在103种期刊和5本书中。1,747种维管植物新种包括被子植物1,689种、蕨类植物52种、裸子植物6种。其中大部分来源于维管植物最大的几个科, 例如菊科、兰科和胡椒科。植物学家描述的美洲南部和热带亚洲维管植物新种超过828种, 是2020年维管植物新种发现最重要的两个地区。中国、巴西和马达加斯加是2020年贡献维管植物新种最多的前三位, 分别有247、223、99个新种。值得关注的是, Phytotaxa和PhytoKeys是2020年发表维管植物新种的主要期刊, 分别发表644种和168种。在各物种新名称中, 有5个无效名称和2个不合法名称。尽管近年来对生物多样性的关注日益增加, 但世界上仍有许多物种尚未被发现, 需要对各个地区植物进一步调查和研究, 尤其是生物多样性热点地区和岛屿地区。     

Suppression of Grb2 expression improved hepatic steatosis, oxidative stress, and apoptosis induced by palmitic acid in vitro partly through insulin signaling alteration

In this study, we aimed to study the role of growth factor receptor-bound protein 2 (Grb2) in palmitic acid-induced steatosis and other “fatty liver” symptoms in vitro. HepG2 cells, with or without stably suppressed Grb2 expression, were incubated with palmitic acid for 24 h to induce typical clinical “fatty liver” features, including steatosis, impaired glucose metabolism, oxidative stress, and apoptosis. MTT and Oil Red O assays were applied to test cell viability and fat deposition, respectively. Glucose uptake assay was used to evaluate the glucose utilization of cells. Quantitative polymerase chain reaction and Western blot were used to measure expressional changes of key markers of insulin signaling, lipid/glucose metabolism, oxidative stress, and apoptosis. After 24-h palmitic acid induction, increased fat accumulation, reduced glucose uptake, impaired insulin signaling, enhanced oxidative stress, and increased apoptosis were observed in HepG2 cells. Suppression of Grb2 in HepG2 significantly reduced fat accumulation, improved glucose metabolism, ameliorated oxidative stress, and restored the activity of insulin receptor substrate-1/Akt and MEK/ERK pathways. In addition, Grb2 deficiency attenuated hepatic apoptosis shown by reduced activation of caspase-3 and fluorescent staining. Modulation of Bcl-2 and Bak1 also contributed to reduced apoptosis. In conclusion, suppression of Grb2 expression in HepG2 cells improved hepatic steatosis, glucose metabolism, oxidative stress, and apoptosis induced by palmitic acid incubation partly though modulating the insulin signaling pathway.     

Role of Complement 3 in TNF-α-Induced Mesenchymal Transition of Renal Tubular Epithelial Cells In Vitro

Injured renal tubular epithelial cells (RTECs) have been recently thought to directly contribute to the accumulation of myofibroblasts in renal tubulointerstitial fibrosis through a process of epithelial to mesenchymal transition (EMT). However, the factors inducing RTECs to undergo EMT and the underlying mechanisms need to be further elucidated. This study aimed to determine the EMT-inducing activity of proinflammatory cytokine TNF-α and the role for complement 3 (C3) in this activity in an in vitro model of human RTECs (HK-2 cells). Wild type HK-2 cells were treated with TNF-α, IFN-γ or C3a; C3 siRNA- or control siRNA-carrying HK-2 cells were treated with TNF-α. Changes in the cell morphology and phenotype were assessed by microscopy, RT-PCR, western blotting, and immunostaining. TNF-α effectively induced HK-2 cells to express C3 and to transform into morphologically myofibroblast-like cells that lost E-cadherin (a classical epithelial cell marker) expression but acquired alpha-smooth muscle actin (α-SMA, a classical myofibroblast differentiation marker) expression. C3 siRNA robustly attenuated all the morphologic and phenotypic changes induced by TNF-α but the control siRNA showed no effect. Our preliminary observations suggest that TNF-α may induce EMT in RTECs through inducing C3 expression.     

Investigation on Side-Spray Fluidized Bed Granulation with Swirling Airflow

Top-spray fluidized bed granulation with axial fluidization airflow from the bottom of the granulator is well-established in the pharmaceutical industry. The application of swirling airflow for fluidized bed granulation was more recently introduced. This study examined the effects of various process parameters on the granules produced by side-spray fluidized bed with swirling airflow using the central composite and Box–Behnken design of experiment. Influence of the amount of binder solution, spray rate, and distance between spray nozzle and powder bed were initially studied to establish operationally viable values for these parameters. This was followed by an in-depth investigation on the effects of inlet airflow rate, atomizing air pressure and distance between spray nozzle and powder bed on granule properties. It was found that the amount of binder solution had a positive correlation with granule size and percentage of lumps but a negative correlation with size distribution and Hausner ratio of the granules. Binder solution spray rate was also found to affect the granules size. High drug content uniformity was observed in all the batches of granules produced. Both inlet airflow rate and atomizing air pressure were found to correlate negatively with granule size and percentage of lumps but correlate positively with the size distribution of the granule produced. Percentage of fines was found to be significantly affected by inlet airflow rate. Distance between spray nozzle and powder bed generally affected the percentage of lumps.     

Molecular Modeling-Based Inclusion Mechanism and Stability Studies of Doxycycline and Hydroxypropyl-β-Cyclodextrin Complex for Ophthalmic Delivery

The aim of the present study was to prepare a stable complex of doxycycline (Doxy) and hydroxypropyl-β-cyclodextrin (HPβCD) for ophthalmic delivery and investigate the inclusion mechanism and the inclusion effects on the stability of Doxy. The Doxy/HPβCD complex was prepared by solution stirring and then characterized by scanning electron microscopy and ultraviolet spectroscopy. Based on results of nuclear magnetic resonance, molecular model of Doxy/HPβCD complex was established using computational simulation of PM3 method implemented in Gaussian 03. Stabilities of Doxy/HPβCD complex in both aqueous solution and solid state at 25°C were evaluated by HPLC. Finally, in vitro antibacterial activity of the Doxy/HPβCD complex was evaluated by disk diffusion test. It was found that the stabilities of Doxy/HPβCD complex in both aqueous solution and solid state were improved obviously as compared with Doxy alone. This stability enhancement is consistent with the inclusion mechanism between HPβCD and Doxy, which showed that the unstable site of Doxy molecule at 6-CH₃ was protected in the hydrophobic cavity of HPβCD, additionally, the chelation of Mg²⁺ provided a synergetic protection of the other unstable site of Doxy at 4-N(CH₃)₂. The antibacterial activity results indicated that Doxy/HPβCD complex might have potential for clinical applications.     

Multi-dimensional Co-separation Analysis Reveals Protein–Protein Interactions Defining Plasma Lipoprotein Subspecies

The distribution of circulating lipoprotein particles affects the risk for cardiovascular disease (CVD) in humans. Lipoproteins are historically defined by their density, with low-density lipoproteins positively and high-density lipoproteins (HDLs) negatively associated with CVD risk in large populations. However, these broad definitions tend to obscure the remarkable heterogeneity within each class. Evidence indicates that each class is composed of physically (size, density, charge) and compositionally (protein and lipid) distinct subclasses exhibiting unique functionalities and differing effects on disease. HDLs in particular contain upward of 85 proteins of widely varying function that are differentially distributed across a broad range of particle diameters. We hypothesized that the plasma lipoproteins, particularly HDL, represent a continuum of phospholipid platforms that facilitate specific protein–protein interactions. To test this idea, we separated normal human plasma using three techniques that exploit different lipoprotein physicochemical properties (gel filtration chromatography, ionic exchange chromatography, and preparative isoelectric focusing). We then tracked the co-separation of 76 lipid-associated proteins via mass spectrometry and applied a summed correlation analysis to identify protein pairs that may co-reside on individual lipoproteins. The analysis produced 2701 pairing scores, with the top hits representing previously known protein–protein interactions as well as numerous unknown pairings. A network analysis revealed clusters of proteins with related functions, particularly lipid transport and complement regulation. The specific co-separation of protein pairs or clusters suggests the existence of stable lipoprotein subspecies that may carry out distinct functions. Further characterization of the composition and function of these subspecies may point to better targeted therapeutics aimed at CVD or other diseases.Lipoproteins are circulating emulsions of protein and lipid that play important roles, both positive and negative, in cardiovascular disease (CVD).¹ Historically defined by their density as separated by ultracentrifugation, the major lipoprotein classes include the neutral lipid ester-rich very low-density and low-density lipoproteins (VLDLs and LDLs, respectively), which function to transport triglyceride and cholesterol from the liver to the peripheral tissues. Significant epidemiological evidence, in vitro studies, animal experiments, and human clinical trials have shown that high-LDL cholesterol is a bona fide causative factor in CVD (1). In contrast, protein- and phospholipid-rich high-density lipoproteins (HDLs) are thought to mediate the reverse transport of cholesterol from the periphery to the liver for catabolism and to perform anti-oxidative and anti-inflammatory functions (reviewed in Refs. 2 and 3). A host of human epidemiology and animal studies indicate that HDLs are atheroprotective (4). However, recent clinical trials of therapeutics that generically raise HDL, at least as measured by its cholesterol levels, have failed to confer the expected CVD protections (5–7).Although these traditional density-centric definitions have been used for nearly 40 years, accumulating evidence indicates that they are not particularly reflective of lipoprotein compositional and functional complexity. With respect to most physical traits (size, charge, lipid content, protein content, etc.), one can demonstrate significant heterogeneity within each density class. This suggests that particle subspecies exist with unique functions and effects on disease. For example, LDL can be resolved into large, buoyant and small, dense forms (8), with subjects carrying more cholesterol in the small, dense LDL exhibiting a greater CVD risk (9). HDL is particularly noted for heterogeneity, as it can be separated into numerous subfractions by density (10), diameter (11), charge (12), and major apolipoprotein content (13). Most strikingly, recent applications of soft-ionization mass spectrometry (MS) have identified upward of 85 HDL proteins with functions that go well beyond the structural apolipoproteins, lipid transport proteins, and lipid-modifying enzymes known from previous biochemical studies (14, 15). Many of these proteins imply functions as diverse as complement regulation, acute phase response, protease inhibition, and innate immunity (16). Individual HDL subspecies can apparently draw from this palette of proteins to produce distinct particles of distinct function. One well-defined HDL subfraction, termed trypanosome lytic factor, contains apolipoprotein apoA-I, haptoglobin-related protein, and apoL-I. Working together, these proteins enter the trypanosome brucei brucei and kill it via lysosomal disruption (17). There are numerous other instances of on-particle protein cooperation in HDL related to CVD (reviewed in Ref. 15). Furthermore, two-dimensional electrophoresis studies by Asztalos and colleagues (18), as well as our own work (11, 19), strongly support the concept that certain apolipoproteins segregate among different HDL particles. These observations present the intriguing possibility that the phospholipids of HDLs act as an organizing platform that facilitates the assembly of specific protein complexes (20). Such subspecies could have important functional implications in the context of CVD protection, inflammation, or even innate immune function. Furthermore, this subspeciation may explain why therapeutics that raise HDL cholesterol levels across the board have not yet shown promise with regard to CVD.To address this hypothesis, we began to think of lipoproteins as a continuum of phospholipid platforms that support the assembly of specific protein complexes analogous to those in cells that perform coordinated biological functions (i.e. ribosomes, centrosomes, etc.). Two common methods for characterizing protein complexes are tandem affinity purification (21) and immunoprecipitation. Both rely on the specific pull-down of a target protein (by either an introduced affinity tag or an antibody) followed by the identification of co-precipitated proteins via MS. Unfortunately, tandem affinity purification strategies are impractical in humans, and we have found that immunoprecipitation experiments with human plasma lipoproteins result in a high false-positive rate due to the low abundance of most of these proteins, particularly those in HDLs. Therefore, we took an alternative approach called co-separation analysis, a method based on the principle that stable protein complexes can be identified by tracking their co-migration as they undergo biochemical separation by multiple orthogonal approaches (22). Native proteins are analyzed in an unbiased manner without affinity tags or antibodies, and purification to homogeneity is not necessary for the identification of putative protein complexes.Most current studies of the lipoprotein proteome utilize samples isolated via density ultracentrifugation because contaminating lipid-unassociated lipoproteins, which can be highly abundant and obscure the identification of targeted lipid-associated proteins, are thus removed prior to the analysis. In previous work, we characterized the use of a calcium silica hydrate (CSH) resin that allowed the specific isolation of phospholipid-associated proteins and their subsequent MS identification without ultracentrifugation (11). This advance enabled the use of a variety of non-density-based separation methods for the study of plasma lipoproteins. Here, we take advantage of this to analyze the proteome of human plasma lipoproteins separated via three separation techniques that exploit different physicochemical properties: (i) gel filtration chromatography (size), (ii) anion exchange chromatography (charge interaction), and (iii) isoelectric focusing. By tracking the co-migration of specific proteins across these separations (Fig. 1), we identified a host of putative protein pairings, including the previously known trypanosome lytic factor HDL fraction, for further biochemical verification and characterization.Open in a separate windowFig. 1.Overview of the multi-dimensional separation co-migration analysis used in this study (see “Experimental Procedures” for details).     

hPNAS-4 inhibits proliferation through S phase arrest and apoptosis: underlying action mechanism in ovarian cancer cells

PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Previous studies have shown that hPNAS-4 can inhibit tumor growth when over-expressed in ovarian cancer cells. However, the underlying action mechanism remains elusive. In this work, we found that hPNAS-4 expression was significantly increased in SKOV3 cells when exposed to cisplatin, methyl methanesulfonate or mitomycin C, and that its overexpression could induce proliferation inhibition, S phase arrest and apoptosis in A2780s and SKOV3 ovarian cancer cells. The S phase arrest caused by hPNAS-4 was associated with up-regulation of p21. p21 is p53-dispensable and correlates with activation of ERK, and activation of the Cdc25A-Cdk2-Cyclin E/Cyclin A pathway, while the pro-apoptotic effects of hPNAS-4 were mediated by activation of caspase-9 and -3 other than caspase-8, and accompanied by release of AIF, Smac and cytochrome c into the cytosol. Taken together, these data suggest a new mechanism by which hPNAS-4 inhibits proliferation of ovarian cancer cells by inducing S phase arrest and apoptosis via activation of Cdc25A-Cdk2-Cyclin E/Cyclin A axis and mitochondrial dysfunction-mediated caspase-dependent and -independent apoptotic pathways. To our knowledge, we provide the first molecular evidence for the potential application of hPNAS-4 as a novel target in ovarian cancer gene therapy.     

VRAA: virtualized resource auction and allocation based on incentive and penalty

Virtualization is widely used in cloud computing environments to efficiently manage resources, but it also raises several challenges. One of them is the fairness issue of resource allocation among virtual machines. Traditional virtualized resource allocation approaches distribute physical resources equally without taking into account the actual workload of each virtual machine and thus often leads to wasting. In this paper, we propose a virtualized resource auction and allocation model (VRAA) based on incentive and penalty to correct this wasting problem. In our approach, we use Nash equilibrium of cooperative games to fairly allocate resources among multiple virtual machines to maximize revenue of the system. To illustrate the effectiveness of the proposed approach, we then apply the basic laws of auction gaming to investigate how CPU allocation and contention can affect applications’ performance (i.e., response time), and its effect on CPU utilization. We find that in our VRAA model, the fairness index is high, and the resource allocation is closely proportional to the actual workloads of the virtual machines, so the wasting of resources is reduced. Experiment results show that our model is general, and can be applied to other virtualized non-CPU resources.