Competition between Hardwood Hammocks and Mangroves

A bstract The boundaries between mangroves and freshwater hammocks in coastal ecotones of South Florida are sharp. Further, previous studies indicate that there is a discontinuity in plant predawn water potentials, with woody plants either showing predawn water potentials reflecting exposure to saline water or exposure to freshwater. This abrupt concurrent change in community type and plant water status suggests that there might be feedback dynamics between vegetation and salinity. A model examining the salinity of the aerated zone of soil overlying a saline body of water, known as the vadose layer, as a function of precipitation, evaporation and plant water uptake is presented here. The model predicts that mixtures of saline and freshwater vegetative species represent unstable states. Depending on the initial vegetation composition, subsequent vegetative change will lead either to patches of mangrove coverage having a high salinity vadose zone or to freshwater hammock coverage having a low salinity vadose zone. Complete or nearly complete coverage by either freshwater or saltwater vegetation represents two stable steady-state points. This model can explain many of the previous observations of vegetation patterns in coastal South Florida as well as observations on the dynamics of vegetation shifts caused by sea level rise and climate change.     

EasyGO: Gene Ontology-based annotation and functional enrichment analysis tool for agronomical species

Following the publication of our recent article (Kapp et al., BMC Genomics 2006, 7:231), we (the authors) regrettably found several errors in the published Table 5. This correction article not only describes what makes the published Table 5 incorrect, it also presents the correct Table 5.     

Mapping phosphoproteins in <Emphasis Type="Italic">Mycoplasma genitalium</Emphasis> and <Emphasis Type="Italic">Mycoplasma pneumoniae</Emphasis>

Background  

Little is known regarding the extent or targets of phosphorylation in mycoplasmas, yet in many other bacterial species phosphorylation is known to play an important role in signaling and regulation of cellular processes. To determine the prevalence of phosphorylation in mycoplasmas, we examined the CHAPS-soluble protein fractions of Mycoplasma genitalium and Mycoplasma pneumoniae by two-dimensional gel electrophoresis (2-DE), using a combination of Pro-Q Diamond phosphoprotein stain and ³³P labeling. Protein spots that were positive for phosphorylation were identified by peptide mass fingerprinting using MALDI-TOF-TOF mass spectrometry.     

Morphologic analysis of the venom gland of Apis mellifera L. (Hymenoptera: Apidae) in populations of Mato Grosso do Sul, Brazil

In Apis mellifera L. the venom gland (also called acid gland) is composed of secretory cells that surround a channel that opens into a reservoir devoid of musculature. This gland can present apical branching. In this study the frequency of branched venom glands in Africanized honeybee workers (A. mellifera) from eleven localities in the state of Mato Grosso do Sul was recorded. The relations among the length of the main duct, the length of the duct from the reservoir to the beginning of branching, the length of the branched segment (when present) and the total length of the gland were also analyzed. The frequency of branched glands varied from 50% to 83% in the workers, indicating that this characteristic is primitive in those bees. The results of the Analysis of Discriminant Functions indicated significant differences in the morphometrical segments of the venom gland (Wilks Lambda = 0.092; F (40, 55) = 3.43; P < 0.001), and permitted a differentiation of the populations studied. Using the Mantel test we verified that there does not exist a significant correlation between the morphologic characteristics and the geographical distance between the localities evaluated (Mantel r = -0.006, P = 0.48). The high frequency of workers with large venom gland in all the apiaries considered makes viable the development of a selection program in order to obtain bees with longer venom glands, aimed at the commercial production of venom by the beekeepers of those localities of Mato Grosso do Sul.     

Mass spectrometry-based strategies for characterization of histones and their post-translational modifications

Due to the intimate interactions between histones and DNA, the characterization of histones has become the focus of great attention. A series of mass spectrometry-based technologies have been dedicated to the characterization and quantitation of different histone forms. This review focuses on the discussion of mass spectrometry-based strategies used for the characterization of histones and their post-translational modifications.     

Binding of the environmental pollutant naphthol to bovine serum albumin

The interactions between naphthol and bovine serum albumin (BSA) were investigated by spectroscopy. Our results prove the formation of complex between naphthol and BSA. Hydrophobic interaction dominates in the association reaction. The isomers stack with the aromatic residues in their binding sites with different geometries. Effects of BSA on the excited-state proton transfer and fluorescence spectra of the isomers indicate the different characters of their binding sites. 1-Naphthol inserts deeply into a hydrophobic cavity whereas 2-naphthol is in a basic environment on the surface of BSA. Naphthol statically quenches the fluorescence of BSA in a concentration-dependent manner positively deviating from the linear Stern-Volmer equation. Naphthol binds near Trp-134 in the subdomain IA of the native BSA and is accessible to Trp-212 when BSA is unfolded by naphthol. The folding pattern of the main chain is altered at high naphthol concentration as revealed by the change in the secondary structure. The binding of 1-naphthol is more cooperative than that of 2-naphthol. The extent of cooperativity was estimated by the Hill equation.     

Pharmacometabonomic phenotyping reveals different responses to xenobiotic intervention in rats

In conventional pharmacological studies, intersubject differences within an animal strain are normally neglected, leading to variations in pharmacological outcomes in response to the same stimulus. Using two classical experimental models, the Streptozotocin (STZ)-induced diabetic model of Wistar rats and the high-energy, diet-induced obesity model of Sprague-Dawley rats, we demonstrate that the different outcomes of STZ or diet intervention are closely associated with variation in predose (baseline) urinary metabolic profiles of the rats. The pharmacometabonomic analysis of predose metabolic profiles indicates that the intersubject difference is, to a great extent, associated with gut-microbiota, which predisposes different pathophysiological outcomes upon diet alteration or chemical stimulus. We hypothesize that there may exist an important association between observations from these two models and the obese/diabetic human population in that subtle variations in metabolic phenotype may predetermine different systems' responses to xenobiotic perturbation, ultimately leading to varied pathophysiological processes. Results from two independent models also suggest that the pharmacometabonomics approach is of great importance in the study of pharmacology and clinical drug evaluations, where endogenous metabolite signatures of predose individuals should be taken into consideration to minimize intersubject difference and the resulting variation in the postdose pharmacological outcomes.     

Nonviral vector-based gene transfection of primary human skeletal myoblasts

Low-level transgene efficiency is one of the main obstacles in ex vivo nonviral vector-mediated gene transfer into primary human skeletal myoblasts (hSkMs). We optimized the cholesterol:N-[1-(2, 3-dioleoyloxy)propyl]-N, N, N-trimethylammonium methylsulfate liposome (CD liposome) and 22-kDa polyethylenimine (PEI22)- and 25-kDa polyethylenimine (PEI25)-mediated transfection of primary hSkMs for angiogenic gene delivery. We found that transfection efficiency and cell viability of three nonviral vectors were cell passage dependent: early cell passages of hSkMs had higher transfection efficiencies with poor cell viabilities, whereas later cell passages of hSkMs had lower transfection efficiencies with better cell viabilities. Trypsinization improved the transfection efficiency by 20% to 60% compared with adherent hSkMs. Optimum gene transfection efficiency was found with passage 6 trypsinized hSkMs: transfection efficiency with CD lipoplexes was 6.99 +/- 0.13%, PEI22 polyplexes was 18.58 +/- 1.57%, and PEI25 polyplexes was 13.32 +/- 0.88%. When pEGFP (a plasmid encoding the enhanced green fluorescent protein) was replaced with a vector containing human vascular endothelial growth factor 165 (phVEGF(165)), the optimized gene transfection conditions resulted in hVEGF(165) expression up to Day 18 with a peak level at Day 2 after transfection. This study demonstrated that therapeutic angiogenic gene transfer through CD or PEI is feasible and safe after optimization. It could be a potential strategy for treatment of ischemic disease for angiomyogenesis.     

抗病毒免疫中干扰素与炎症信号通路的交互调控：防御反应与维持稳态

天然免疫是机体通过识别自身或外部危险信号后,为维持体内稳态而逐步建立起来的一系列防御反应,当宿主细胞内的模式识别受体识别胞内病原相关分子模式后激活干扰素(interferon, IFN)、核因子-kappa B (nuclear factor-kappa B, NF-κB)和炎性小体等信号通路。IFNs在天然免疫应答中发挥重要作用,它诱导的抗病毒基因能够通过多种方式抵御病毒的感染,炎症反应则是机体自动的防御反应,能够在病毒感染机体时释放促炎性细胞因子以调控机体的免疫反应,进而发挥抗病毒作用。在病毒感染过程中,IFN信号通路与炎症反应调控网络中的关键分子如NF-κB/RelA、PKR等存在一定的交互作用,此外,IFN信号通路及其产生的细胞因子又影响其他信号通路的活化,进而调控机体的免疫应答以维持自身稳态,它们之间的交互调控失衡将会引起过度炎症反应,导致组织器官的免疫病理损伤,例如SARS-CoV-2感染机体时产生的过度炎症反应。本文综述了机体抗病毒免疫过程中干扰素信号通路与炎症反应之间的交互调控,为研发抗病毒策略提供新思路。     

Exogenous Glycine Betaine Reduces Drought Damage by Mediating Osmotic Adjustment and Enhancing Antioxidant Defense in <i>Phoebe hunanensis</i>

Drought stress negatively impacts growth and physiological processes in plants. The foliar application of glycine betaine (GB) is an effective and low-cost approach to improve the drought tolerance of trees. This study examined the effect of exogenously applied GB on the cell membrane permeability, osmotic adjustment, and antioxidant enzyme activities of Phoebe hunanensis Hand.-Mazz under drought stress. Two levels (0 and 800 mL) of water irrigation were tested under different applied GB concentrations (0, 50, 100, and 200 mM). Drought stress decreased the relative water content by 58.5% while increased the electric conductivity, malondialdehyde, proline, soluble proteins, soluble sugars, and antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase) by up to 62.9%, 42.4%, 87.0%, 19.1%, 60.5%, 68.3%, 71.7%, and 83.8%, respectively, on the 25^th day. The foliar application of GB, especially at 100 mM, increased the relative water content of P. hunanensis leaves under drought stress. The concentration of GB from 50 to 100 mM effectively alleviated the improvement of cell membrane permeability and inhibited the accumulation of membrane lipid peroxidation products. Under drought stress, the concentrations of proline, soluble proteins, and soluble sugars in the leaves of P. hunanensis increased as the applied GB concentration was increased and the water stress time was prolonged. Exogenously applied GB decreased oxidative stress and improved antioxidant enzyme activities as compared with treatments without GB application. Furthermore, the physiological and biochemical indexes of P. hunanensis showed a certain dose effect on exogenous GB concentration. These results suggest that GB helps maintain the drought tolerance of P. hunanensis.