Reconciling deep calibration and demographic history: bayesian inference of post glacial colonization patterns in Carcinus aestuarii (Nardo, 1847) and C. maenas (Linnaeus, 1758)

A precise inference of past demographic histories including dating of demographic events using bayesian methods can only be achieved with the use of appropriate molecular rates and evolutionary models. Using a set of 596 mitochondrial cytochrome c oxidase I (COI) sequences of two sister species of European green crabs of the genus Carcinus (C. maenas and C. aestuarii), our study shows how chronologies of past evolutionary events change significantly with the application of revised molecular rates that incorporate biogeographic events for calibration and appropriate demographic priors. A clear signal of demographic expansion was found for both species, dated between 10,000 and 20,000 years ago, which places the expansions events in a time frame following the Last Glacial Maximum (LGM). In the case of C. aestuarii, a population expansion was only inferred for the Adriatic-Ionian, suggestive of a colonization event following the flooding of the Adriatic Sea (18,000 years ago). For C. maenas, the demographic expansion inferred for the continental populations of West and North Europe might result from a northward recolonization from a southern refugium when the ice sheet retreated after the LGM. Collectively, our results highlight the importance of using adequate calibrations and demographic priors in order to avoid considerable overestimates of evolutionary time scales.     

Extracellular ATP induces cytokine expression and apoptosis through P2X7 receptor in murine mast cells

Extracellular ATP and other nucleotides act through specific cell surface receptors and regulate a wide variety of cellular responses in many cell types and tissues. In this study, we demonstrate that murine mast cells express several P2Y and P2X receptor subtypes including P2X(7), and describe functional responses of these cells to extracellular ATP. Stimulation of bone marrow-derived mast cells (BMMC), as well as MC/9 and P815 mast cell lines with millimolar concentrations of ATP, resulted in Ca(2+) influx across the cellular membrane and cell permeabilization. Moreover, brief exposures to ATP were sufficient to induce apoptosis in BMMCs, MC/9, and P815 cells which involved activation of caspase-3 and -8. However, in the time period between commitment to apoptosis and actual cell death, ATP triggered rapid but transient phosphorylation of multiple signaling molecules in BMMCs and MC/9 cells, including ERK, Jak2, and STAT6. In addition, ATP stimulation enhanced the expression of several proinflammatory cytokines, such as IL-4, IL-6, IL-13, and TNF-alpha. The effects of ATP were mimicked by submillimolar concentrations of 3-O-(4'-benzoyl)-benzoyl-benzoyl-ATP, and were inhibited by pretreatment of mast cells with a selective blocker of human and mouse P2X(7) receptor, 1[N,O-bis(5-isoquinolinesulphonyl)-N-methyl-l-tyrosyl]-4-phenylpiperazine, as well as oxidized ATP. The nucleotide selectivity and pharmacological profile data support the role for P2X(7) receptor as the mediator of the ATP-induced responses. Given the importance of mast cells in diverse pathological conditions, the ability of extracellular ATP to induce the P2X(7)-mediated apoptosis in these cells may facilitate the development of new strategies to modulate mast cell activities.     

Characterization of microsatellite DNA markers in a critically endangered species,Mekong giant catfish,Pangasianodon gigas

Microsatellite DNA markers for a critically endangered Mekong giant catfish (Pangasianodon gigas Roberts and Vidthayanon, 1991) were developed from fin clips collected from captive fish using (GT)₁₅ probe. The number of alleles per locus ranged from two to four. The expected heterozygosities ranged from 0.13 to 0.68. Also, these primers were successfully amplified in four closely related species, Pangasius bocourti, Pangasius conchophilus, Pangasius larnaudii and Pangasius sanitwongsei with the number of alleles per locus ranged from 1 to 13, 1 to 16, 1 to 12 and 1 to 4, respectively. These markers should prove to be very useful for the evaluation of genetic diversity for this species and other related Pangasius species.     

Interactions between Lipids and Human Anti-HIV Antibody 4E10 Can Be Reduced without Ablating Neutralizing Activity

Human 4E10 is one of the broadest-specificity, HIV-1-neutralizing monoclonal antibodies known, recognizing a membrane-proximal linear epitope on gp41. The lipid cross-reactivity of 4E10 has been alternately suggested either to contribute to the apparent rarity of 4E10-like antibody responses in HIV infections, through elimination by B-cell tolerance mechanisms to self-antigens, or to contribute to neutralization potency by virus-specific membrane binding outside of the membrane-proximal external region (MPER). To investigate how 4E10 interacts with membrane and protein components, and whether such interactions contribute to neutralization mechanisms, we introduced two mutations into 4E10 Fv constructs, Trp to Ala at position 100 in the heavy chain [W(H100)A] and Gly to Glu at position 50 in the light chain [G(L50)E], selected to disrupt potential lipid interactions via different mechanisms. Wild-type and mutant Fvs all bound with the same affinity to peptides and monomeric and trimeric gp140s, but the affinities for gp140s were uniformly 10-fold weaker than to peptides. 4E10 Fv binding responses to liposomes in the presence or absence of MPER peptides were weak in absolute terms, consistent with prior observations, and both mutations attenuated interactions even further, as predicted. The W(H100)A mutation reduced neutralization efficiency against four HIV-1 isolates, but the G(L50)E mutation increased potency across the same panel. Electron paramagnetic resonance experiments showed that the W(H100)A mutation, but not the G(L50)E mutation, reduced the ability of 4E10 to extract MPER peptides from membranes. These results show that 4E10 nonspecific membrane binding is separable from neutralization, which is achieved through specific peptide/lipid orientation changes.Few of the hundreds of known neutralizing anti-HIV monoclonal antibodies (MAbs) display broad cross-reactive activities (4). Of those derived from clade B-infected patients, b12 binds to the gp120 subunit of the HIV envelope protein (Env), to an epitope that overlaps the CD4 binding site, and neutralizes approximately 50% of virus isolates tested, including non-clade B viruses (27). 2G12 binds to N-linked carbohydrates on gp120 (32, 34) and neutralizes 41% of isolates tested, although not clade C or E isolates. 447-52D also binds to the gp120 subunit, to an epitope within the V3 loop, and potently neutralizes up to 45% of clade B isolates but rarely non-clade B isolates. 4E10 and 2F5 recognize adjacent epitopes located at the membrane-proximal external region (MPER) of the gp41 Env subunit (9, 22, 24, 28, 42). Two neutralizing antibodies (NAbs) isolated from a clade A-infected patient (PG9 and PG16) show broad and potent neutralizing activity by recognizing epitopes consisting of conserved regions of the V2 and V3 loops of gp120, preferentially on native trimers (40).4E10 is capable of neutralizing all isolates tested at some level (4), although there is evidence for the existence of rare viruses that are resistant to 4E10 neutralization (30). The exact structure of the epitope recognized by 4E10 within the trimeric, functional HIV Env is unknown, but structural studies have shown that an isolated peptide spanning the epitope adopts a helical conformation, a short 3₁₀ segment followed by a 4₁₃ (or true α-helical) segment, with an extended structure at the N terminus when bound to 4E10 (9). It has also been reported that 4E10 interacts with a variety of lipids and membrane components, particularly the phospholipid cardiolipin (15), suggesting that difficulties in eliciting 4E10-like broadly neutralizing antibodies by immunization and the apparent rarity of 4E10-like antibody responses in HIV-1-infected subjects (19, 33) are linked to this polyspecificity to autoantigens, contributing to their elimination through tolerance mechanisms. However, subsequent studies have shown that the measurable, but quite weak, affinity of 4E10 for certain lipids is comparable to that of some antiphospholipid antibodies elicited during many infections, suggesting that 4E10 is not remarkably autoreactive (35). Therefore, it is still unclear whether lipid binding properties are linked to the rarity of 4E10-like specificities. It has also been proposed that the neutralizing activity of 4E10 may partly depend on lipid binding, either through interactions with viral membrane lipids that disturb the membrane-bound structure of the MPER on the trimeric, virion-associated Env spike (39) or through an encounter model. In the latter, initial interactions with membrane components align 4E10 with its protein epitope or allow 4E10 to gain proximity to its epitope (1), perhaps partially alleviating steric occlusion effects (for example, see reference 17). We sought to determine whether specific interactions exist between 4E10 and membrane lipid components and whether such interactions meaningfully contribute to neutralization by any mechanism.     

Phylogenetic relationships and demographic histories of the Atherinidae in the Eastern Atlantic and Mediterranean Sea re-examined by Bayesian inference

The aim of our study is to examine the phylogenetic relationship, divergence times and demographic history of the five close-related Mediterranean and North-eastern Atlantic species/forms of Atherina using the full Bayesian framework for species tree estimation recently implemented in ?BEAST. The inference is made possible by multilocus data using three mitochondrial genes (12S rRNA, 16S rRNA, control region) and one nuclear gene (rhodopsin) from multiple individuals per species available in GenBank. Bayesian phylogenetic analysis of the complete gene dataset produced a tree with strong support for the monophyly of each species, as well as high support for higher level nodes. An old origin of the Atherina group was suggested (19.2 MY), with deep split events within the Atherinidae predating the Messinian Salinity Crisis. Regional genetic substructuring was observed among populations of A. boyeri, with AMOVA and MultiDimensional Scaling suggesting the existence of five groupings (Atlantic/West Mediterranean, Adriatic, Greece, Black Sea and Tunis). The level of subdivision found might be consequence of the hydrographic isolation within the Mediterranean Sea. Bayesian inference of past demographic histories showed a clear signature of demographic expansion for the European coast populations of A. presbyter, possibly linked to post-glacial colonizations, but not for the Azores/Canary Islands, which is expected in isolated populations because of the impossibility of finding new habitats. Within the Mediterranean, signatures of recent demographic expansion were only found for the Adriatic population of A. boyeri, which could be associated with the relatively recent emergence of the Adriatic Sea.     

Effects of various warm-up devices and rest period lengths on batting velocity and acceleration of intercollegiate baseball players

It is common among competitive baseball players to swing bats while in the batter's box in an attempt to improve their batting performance. Players use bats of different weights during this time, and only a few studies have evaluated the optimal bat weight to increase performance. Previous studies have not investigated the optimal rest period after a warm-up with bats of varying weights. Therefore, we tested the peak bat velocity of 16 National Collegiate Athletic Association Division II intercollegiate baseball players at 1, 2, 4, and 8 minutes, after warming up with bats of 5 different weights. Measured variables were peak bat velocity at peak acceleration (PVPA), peak bat velocity of the swing (PV), peak bat acceleration (PA), and time to reach peak acceleration (TPA) using a chronograph, which measured the batting velocity in real time every 10 milliseconds throughout the swing. A repeated measure analysis of variance was run to assess group, time, and group by time interactions. If any main effects were found, a Tukey post hoc was employed to locate differences. There were significant (p ≤ 0.05) time effects for PVPA, PV, and PA but not for TPA. The PVPA, PV, and PA all increased over time, peaking from 4 to 8 minutes. There were no significant differences in any of the variables among the 5 bat weights used in the warm-up (p > 0.05). However, there were significant differences in PVPA, PV, and PA after 2, 4, and 8 minutes of rest compared with the preexperimental warm-up and 1-minute post-warm-up. From a practical standpoint, batters should warm up early and quickly in the batter's box to maximize the amount of recovery time before they swing at the plate. In addition, batters may want to take their time getting ready at the plate or take some pitches while at-bat in an attempt to maximize performance. Alternatively, the data imply that pitchers should throw their fastest pitch near the beginning of the at-bat to correspond with the potentially slower bat speeds of the batter.     

大苞藤黄化学成分研究及其互变异构体超高效液相色谱质谱联用分析

从大苞藤黄枝叶的混合粉碎物中分离到11个化合物,运用光谱手段分别鉴定为neobractatin(1),brasixanthone B (2),5-O-methylxanthone V1 (3),10-O-methylmacluraxanthone (4),isobractatin (5),xanthone V1(6),xerophenone A (7),xerophenone B (8),bractatin (9),macluraxanthone (10)和3-O-methylneobractatin (11).本文首次应用超高效液相色谱-质谱联用技术分离了异构体7和8并测定了其精确分子量.其中化合物6～8为首次从该植物中发现.     

无陪护老年病人住院期间护理需求的质性研究

目的:了解无陪护老年病人在住院期间的护理需求。方法:采用质性研究中现象学研究的半结构化、面对面、深度访谈方法采访11位内科无陪护老年病人,之后依据Claizzit的现象学资料7步分析法分析、整理资料。结果:无陪护老年病人住院期间的需求涉及病室、护理人员、陪护人员三方面。结论:无陪护老年病人住院期间有着其特殊需求,无陪护的原因主要有经济因素及陪护人员综合素质较低、无统一管理等,所以除了医院在护理工作中针对这类病人给予一些特殊照护外,呼吁政府建立规范的陪护人员培训及管理机构,为广大患者提供正规、专业化的陪护。