Characterization of the transient species generated by the photoexcitation of C-phycocyanin from Spirulina platensis: a laser photolysis and pulse radiolysis study

Nanosecond laser flash photolysis and pulse radiolysis were used to generate and characterize the triplet state and cation radical of C-phycocyanin (C-PC) from Spirulina platensis. The transient absorption spectra of C-PC were measured from direct excitation and acetone sensitization in aqueous solution at room temperature by KrF (248 nm) laser flash photolysis. Laser-induced transient species have been characterized by the method of acetone sensitization and one-electron oxidation. In nitrous oxide-saturated phosphate buffer saline (pH = 7.0) of C-PC, the produced intermediates are assigned to the excited triplet state and the radical cation. Using acetone as photosensitizer, the C-PC excited triplet states produced via triplet-triplet energy transfer and the C-PC radical cation from electron transfer reaction were further confirmed. Furthermore, the corresponding kinetic parameters were determined. To our knowledge, the transient absorption spectra of C-PC have been reported for the first time.     

Associations between primates and other mammals in a central Amazonian forest landscape

Little information exists on mixed-species groups between primates and other mammals in Neotropical forests. In this paper, we describe three such associations observed during an extensive large-vertebrate survey in central Amazonia, Brazil. Mixed-species groups between a primate species and another mammal were observed on seven occasions between squirrel monkeys (Saimiri cf. ustus) and either South American coatis (Nasua nasua) or tayras (Eira barbara) and between brown capuchins (Cebus apella) and coatis. All associations were restricted to floodplain forest during its dry stage. We suggest that the associations involving the coatis are connected to foraging and vigilance but may be induced by a common alternative food resource at a time of food shortage.     

Temporal correlation of the memory deficit with Alzheimer-like lesions induced by activation of glycogen synthase kinase-3

We have reported that activation of glycogen synthase kinase-3 (GSK-3) by ventricle injection of wortmannin (WT) and GF-109203X (GFX) induces Alzheimer-like memory deficit in rats [Liu et al., J. Neurochem. 87 (2003), 1333]. To further explore the factors responsible for the memory loss, we studied here the temporal alterations of GSK-3, tau phosphorylation, beta-amyloid (Abeta), and acetylcholine (ACh) after injection of WT/GFX, and analyzed their correlation with the memory loss. We observed that the severe memory deficit occurred at 24 and 48 h, and simultaneously, GSK-3 activation, tau hyperphosphorylation at Thr231, Ser396, and Ser404 and decline of ACh in hippocampus were detected, and these changes were mostly recovered at 72 and 96 h after the injection of WT/GFX. Remarkable increase of Abeta and intracellular accumulation of argentophilic substances were detected at 72 h. Pearson analysis showed that the memory deficit was correlated with GSK-3 activation, tau hyperphosphorylation, and decline of ACh but not with Abeta overproduction. Our data provide direct evidence demonstrating that activation of GSK-3 by WT/GFX may cause memory deficit through tau hyperphosphorylation and suppression of ACh in hippocampus.     

NF-κB、IκB、IKK在非小细胞肺癌中的表达及意义

目的检测非小细胞肺癌(non-small cell lung cancer,NSCLC)中NF-κB P65、p-IκBα(IκBα磷酸化)、p-IKKβ(IKKβ磷酸化)的表达情况及其与NSCLC临床特征的关系。方法采用免疫组化Elivision法检测NF-κB P65、p-IκBα、p-KKβ在56例NSCLC中表达情况,以20例癌旁组织作为对照。结果在NSCLC中NF-κB P65、p-IκBα、p-IKKβ的表达阳性率分别为83.9%(47/56)、55.7%(31/56)、69.6%(39/56),癌旁组织三者分别为20%(4/20)、25%(5/20)、30%(6/20),NF-κB P65、p-IκBα、p-IKKβ的表达与吸烟史、TNM分期、淋巴结转移相关,差异有统计学意义(P<0.05)。结论 NF-κB P65、p-IκBα、p-IKKβ高表达与NSCLC的发生、发展起着重要作用。     

Integrated analysis of multiple data sources reveals modular structure of biological networks

It has been a challenging task to integrate high-throughput data into investigations of the systematic and dynamic organization of biological networks. Here, we presented a simple hierarchical clustering algorithm that goes a long way to achieve this aim. Our method effectively reveals the modular structure of the yeast protein-protein interaction network and distinguishes protein complexes from functional modules by integrating high-throughput protein-protein interaction data with the added subcellular localization and expression profile data. Furthermore, we take advantage of the detected modules to provide a reliably functional context for the uncharacterized components within modules. On the other hand, the integration of various protein-protein association information makes our method robust to false-positives, especially for derived protein complexes. More importantly, this simple method can be extended naturally to other types of data fusion and provides a framework for the study of more comprehensive properties of the biological network and other forms of complex networks.     

Acorn mast drives long-term dynamics of rodent and songbird populations

Resource pulses can have cascading effects on the dynamics of multiple trophic levels. Acorn mast is a pulsed resource in oak-dominated forests that has significant direct effects on acorn predators and indirect effects on their predators, prey, and pathogens. We evaluated changes in acorn mast, rodent abundance, raptor abundance, and reproductive success of a ground-nesting songbird over a 24-year period (1980–2004) in the southern Appalachian Mountains in an effort to determine the relationships among the four trophic levels. In particular, we examined the following: acorn mast from red oaks (Quercus rubra) and white oaks (Q. alba), abundance of white-footed mice (Peromyscus leucopus) and deer mice (P. maniculatus), population estimates of seven raptor species from three feeding guilds, and nest failure and number of juveniles of dark-eyed juncos (Junco hyemalis). Finally, we recorded seasonal temperature and precipitation to determine the effects of weather on each trophic level. We found that weather patterns had delayed effects of up to 3 years on these trophic interactions. Variation in acorn mast, the keystone resource in this community, was explained by weather conditions as far back as 2 years before the mast event. Acorn mast, in turn, was a strongly positive predictor of rodent abundance the following year, whereas spring and summer temperature and raptor abundance negatively affected rodent abundance. Dark-eyed junco nests were more likely to fail in years in which there were more rodents and raptors. Nest failure rate was a strong predictor of the number of juvenile juncos caught at the end of the summer. Our results improve our understanding of the complex ecological interactions in oak-dominated forests by illustrating the importance of abiotic and biotic factors at different trophic levels. Ethan D. Clotfelter and Amy B. Pedersen contributed equally to the writing of this paper.     

绿色糖单孢菌-木素过氧化物酶的发酵工艺研究

本研究以一株中度耐热耐碱放线菌--绿色糖单孢菌(Saccharomonospora viridis)为研究对象,用16 L发酵罐对该菌进行了木素过氧化物酶(lignin peroxidases, LiP)的诱导发酵,确定了最适的产酶工艺条件:接种量为10%,C/N为1∶3,搅拌速度为250 r/min,通气量为5 L/min,通过控制通气量和调整搅拌转速,使溶氧维持在35%以上,此条件下绿色糖单孢菌较摇瓶实验提前将近24 h达到产酶高峰,酶活最高可达0.41 U/ml;同时在发酵罐中测定该菌株的生长曲线和代谢曲线以确定其发酵代谢规律.     

QF-PCR在染色体异常男性不育症诊断中的应用

为评估定量荧光PCR(QF-PCR)方法在男性不育遗传学诊断中的应用价值,文章对78例非梗阻性男性不育患者,采用精液常规检测精子情况,并检测患者性激素水平;采用QF-PCR方法对患者性染色体多态性STR位点及特异性位点进行检测;采用常规染色体G显带方法进行核型分析;PCR检测AZF微缺失。结果显示78例非梗阻性男性不育患者中发现无精子症患者18例,少精子症患者20例,总检出率为48.72%。采用QF-PCR方法检出3例47,XXY患者,2例46,XX(SRY+)性反转患者,1例AZFc区微缺失患者,与细胞培养染色体分析和AZF微缺失PCR检测结果相符。与传统方法相比,QF-PCR技术能更迅速、直接、可靠地检测到男性不育患者的染色体异常区域,及早发现染色体细微结构异常,有助于染色体异常造成的男性不育症的鉴别诊断。     

Greenhouse gas emissions and carbon sequestration potential in restored wetlands of the Canadian prairie pothole region

North American prairie pothole wetlands are known to be important carbon stores. As a result there is interest in using wetland restoration and conservation programs to mitigate the effects of increasing greenhouse gas concentration in the atmosphere. However, the same conditions which cause these systems to accumulate organic carbon also produce the conditions under which methanogenesis can occur. As a result prairie pothole wetlands are potential hotspots for methane emissions. We examined change in soil organic carbon density as well as emissions of methane and nitrous oxide in newly restored, long-term restored, and reference wetlands across the Canadian prairies to determine the net GHG mitigation potential associated with wetland restoration. Our results indicate that methane emissions from seasonal, semi-permanent, and permanent prairie pothole wetlands are quite high while nitrous oxide emissions from these sites are fairly low. Increases in soil organic carbon between newly restored and long-term restored wetlands supports the conclusion that restored wetlands sequester organic carbon. Assuming a sequestration duration of 33 years and a return to historical SOC densities we estimate a mean annual sequestration rate for restored wetlands of 2.7 Mg C ha⁻¹year⁻¹ or 9.9 Mg CO₂ eq. ha⁻¹ year⁻¹. Even after accounting for increased CH₄ emissions associated with restoration our research indicates that wetland restoration would sequester approximately 3.25 Mg CO₂ eq. ha⁻¹year⁻¹. This research indicates that widescale restoration of seasonal, semi-permanent, and permanent wetlands in the Canadian prairies could help mitigate GHG emissions in the near term until a more viable long-term solution to increasing atmospheric concentrations of GHGs can be found.