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91.
Molecular phylogenetics reveal multiple tertiary vicariance origins of the African rain forest trees
Background
Tropical rain forests are the most diverse terrestrial ecosystems on the planet. How this diversity evolved remains largely unexplained. In Africa, rain forests are situated in two geographically isolated regions: the West-Central Guineo-Congolian region and the coastal and montane regions of East Africa. These regions have strong floristic affinities with each other, suggesting a former connection via an Eocene pan-African rain forest. High levels of endemism observed in both regions have been hypothesized to be the result of either 1) a single break-up followed by a long isolation or 2) multiple fragmentation and reconnection since the Oligocene. To test these hypotheses the evolutionary history of endemic taxa within a rain forest restricted African lineage of the plant family Annonaceae was studied. Molecular phylogenies and divergence dates were estimated using a Bayesian relaxed uncorrelated molecular clock assumption accounting for both calibration and phylogenetic uncertainties. 相似文献92.
Suresh Babu CV Song EJ Babar SM Yoo YS 《Journal of biochemical and biophysical methods》2008,70(6):838-844
Phospholamban (PLN) is a key regulatory protein involved in cardiac calcium signaling through the pumping of cytoplasmic Ca2+ into the sarcoplasmic reticulum (SR). Recent systems-level studies have focused on integrating quantitative data (e.g. protein expression levels) for a better understanding of cardiac systems biology. In this view, we developed a capillary electrophoresis (CE) based immunoprecipitation method for the measurement of phospho-PLN (ser 16) in cardiomyocytes (HL-1 cell line). Dose-dependent isoproterenol (Iso) treated cells were analyzed using CE, and the phospho-PLN levels were quantified using specific polyclonal antibodies. The CE method employed was accurate, quick and easier compare to other techniques and the results are useful for the subsequent computational systems biology research. 相似文献
93.
The tandemly arranged MS4 repeat with monomeric units of 4.1 kb is species-specifically distributed in heterochromatin of sex chromosomes of four common vole species of genus Microtus, group arvalis [1, 2]. In this work, we studied the genomic organization of the MS4 homolog in euchromatin of the X chromosome of M. arvalis. It has been shown by analyzing the phage genomic clones that one MS4 copy makes a part of a monomeric unit exceeding 8.5 kb that also includes a new MS7 repeat and, possibly, LINE fragments. MS7 is located together with MS4 in heterochromatin of common vole sex chromosomes, but in a substantially lesser amount. Probably, as a result of an evolutionary transition of an original repeat from euchromatin of the X chromosome to heterochromatin of the Y chromosome, MS4 underwent multiple amplification, and MS7 spread throughout heterochromatin, being surrounded by the MS4 tandem arrays. 相似文献
94.
Studying variations in behaviour at the individual or population level enables insight into the reproductive strategies within a species. We examined individual and geographical variation in the vocal and dive behaviour of male harbour seals, Phoca vitulina, which is associated with aquatic mating. This display behaviour was recorded in the Moray Firth, Scotland, from July 1994 to 1997, and in Orkney, Scotland, during July 1998. One vocalization type was apparent in the Moray Firth and two in Orkney. Time parameters (total and pulse duration) varied between males in the population in the Moray Firth. We used both frequency and time parameters in a discriminant analysis, which showed that 73.2% of individual male vocalizations could be correctly classified; 94.6% of male vocalizations from the Moray Firth and Orkney could be correctly classified according to their geographical areas. Therefore, vocal variation was greater between geographical areas than between individuals. No individual variation was apparent between dive and surface interval durations. However, individuals varied significantly in the percentage of short surface intervals. Male harbour seals showed substantial variability in the parameters affecting their vocal and dive behaviour during the mating season. We suggest that these variations may be indicative of adaptations to varying environmental challenges influencing the reproductive strategies of discrete populations. Copyright 2000 The Association for the Study of Animal Behaviour. 相似文献
95.
Janice J. Hwang Andrea Johnson Gary Cline Renata Belfort-DeAguiar Denis Snegovskikh Babar Khokhar Christina S. Han Robert S. Sherwin 《PloS one》2015,10(6)
Background
Fructose, unlike glucose, promotes feeding behavior in rodents and its ingestion exerts differential effects in the human brain. However, plasma fructose is typically 1/1000th of glucose levels and it is unclear to what extent fructose crosses the blood-brain barrier. We investigated whether local endogenous central nervous system (CNS) fructose production from glucose via the polyol pathway (glucose→sorbitol→fructose) contributes to brain exposure to fructose.Methods
In this observational study, fasting glucose, sorbitol and fructose concentrations were measured using gas-chromatography-liquid mass spectroscopy in cerebrospinal fluid (CSF), maternal plasma, and venous cord blood collected from 25 pregnant women (6 lean, 10 overweight/obese, and 9 T2DM/gestational DM) undergoing spinal anesthesia and elective cesarean section.Results
As expected, CSF glucose was ~60% of plasma glucose levels. In contrast, fructose was nearly 20-fold higher in CSF than in plasma (p < 0.001), and CSF sorbitol was ~9-times higher than plasma levels (p < 0.001). Moreover, CSF fructose correlated positively with CSF glucose (ρ 0.45, p = 0.02) and sorbitol levels (ρ 0.75, p < 0.001). Cord blood sorbitol was also ~7-fold higher than maternal plasma sorbitol levels (p = 0.001). There were no differences in plasma, CSF, and cord blood glucose, fructose, or sorbitol levels between groups.Conclusions
These data raise the possibility that fructose may be produced endogenously in the human brain and that the effects of fructose in the human brain and placenta may extend beyond its dietary consumption. 相似文献96.
Significant levels of circulating immune complexes (ICs) containing rheumatoid factors and immunoglobulin G in peripheral
blood are a characteristic feature of rheumatoid arthritis (RA). ICs interact through Fcγ receptors (FcγR) to activate phagocytes
in numerous inflammatory processes. The high concentration of neutrophils in synovial fluid during active phases of the disease,
together with their destructive capacity, pose important questions as to their role in the pathogenesis of RA. Functional
defects in RA or control peripheral blood neutrophil FcγRs were examined with a specific FcγR-mediated reactive oxygen species
(ROS) assay. Heterologous cross-linking of FcγRIIa and FcγRIIIb on neutrophils resulted in a significantly decreased production
of ROS by RA cells compared with controls matched for age and sex. However, expression and homologous ligation of receptors
did not differ between these groups. These data suggest that neutrophil priming does occur before emigration into the joint
and that blood neutrophils from patients with RA have a functional impairment in cooperative FcγR-mediated ROS generation.
This may account for the increased susceptibility to bacterial infection that arises in patients with severe disease. 相似文献
97.
98.
降解烤烟秸秆和烟碱菌株的筛选及其产酶特性 总被引:1,自引:0,他引:1
摘要:【目的】为获得能够降解烤烟秸秆和烟碱的菌株,并探索其降解烤烟秸秆的利用途径。【方法】以烤烟秸秆为唯一碳氮源,从烟田土壤中进行了菌株的筛选。采用形态学观察、生理生化特性鉴定、16S rRNA基因序列鉴定等方法对该菌株进行了鉴定,并对其以烤烟秸秆为底物进行液态发酵的产酶活性和木质纤维素降解效果进行了测定。【结果】结果表明:该菌株为巨大芽孢杆菌(Bacillus megaterium)。在以烤烟秸秆为主要营养物质液态发酵条件下该菌株具有较强的木质素降解能力,最大漆酶活力达到418.52 U/L,而木质素过氧化物酶和锰过氧化物酶的最大酶活分别为19.71 U/L 和64.71 U/L。此外,发酵20 d后该菌能够完全降解发酵液中的烟碱。【结论】本研究筛选到了1株能够较好降解烤烟秸秆和完全降解烟碱的巨大芽孢杆菌(Bacillus megaterium),且该菌株具有利用烤烟秸秆生产漆酶的应用价值。 相似文献
99.
Praveen Bawankar Philip J. Shaw Richa Sardana Prasad H. Babar Swati Patankar 《Molecular biology reports》2010,37(4):2125-2133
5′ caps provide recognition sequences for the nuclear import of snRNAs. The 5′ and 3′ ends of snRNAs were studied in Plasmodium falciparum with a modified adapter ligation method, which showed that 5′ ends of U1, U2, U4, U5 and U6 snRNAs are capped. In P. falciparum, the 3′ ends of U1, U2, U4 and U5 snRNAs have free hydroxyl groups whereas U6 snRNA has a blocked 3′ end. An immunoprecipitation
assay for trimethyl guanosine caps shows that the cap structures of parasite U1-U5 snRNAs are hypermethylated while U6 snRNA
may be γ-mono-methylated. Bioinformatics analysis of proteins involved in hypermethylation and trafficking of snRNAs indicates
that the methyltransferase TGS1 is present in the P. falciparum genome. PfTGS1 is larger than its orthologs and may have transmembrane domains in the C-terminus. Surprisingly, the snRNA
trafficking protein Snurportin is absent from the P. falciparum genome suggesting that reminiscent of yeast, parasite snRNAs may be retained in the nucleus. 相似文献
100.
The effects of methyl jasmonate (MJ) and salicylic acid (SA) on changes of the activities of major antioxidant enzymes, superoxide anion accumulation (O2
−), ascorbate, total glutathione (TG), malondialdehyde (MDA) content and ginsenoside accumulation were investigated in ginseng roots (Panax ginseng L.) in 4 l (working volume) air lift bioreactors. Single treatment of 200 μM MJ and SA to P. ginseng roots enhanced ginsenoside accumulation compared to the control and harvested 3, 5, 7 and 9 days after treatment. MJ and SA treatment induced an oxidative stress in P. ginseng roots, as shown by an increase in lipid peroxidation due to rise in O2
− accumulation. Activity of superoxide dismutase (SOD) was inhibited in MJ-treated roots, while the activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), SOD, guaiacol peroxidase (G-POD), glutathione peroxidase (GPx) and glutathione reductase (GR) were induced in SA-treated roots. A strong decrease in the activity of catalase (CAT) was obtained in both MJ- and SA-treated roots. Activities of ascorbate peroxidase (APX) and glutathione S transferase (GST) were higher in MJ than SA while the contents of reduced ascorbate (ASC), redox state (ASC/(ASC+DHA)) and TG were higher in SA- than MJ-treated roots while oxidized ascorbate (DHA) decreased in both cases. The result of these analyses suggests that roots are better protected against the O2
− stress, thus mitigating MJ and SA stress. The information obtained in this work is useful for efficient large-scale production of ginsenoside by plant-root cultures. 相似文献