Growth of Western Australian corals in the anthropocene

Anthropogenic increases of atmospheric carbon dioxide lead to warmer sea surface temperatures and altered ocean chemistry. Experimental evidence suggests that coral calcification decreases as aragonite saturation drops but increases as temperatures rise toward thresholds optimal for coral growth. In situ studies have documented alarming recent declines in calcification rates on several tropical coral reef ecosystems. We show there is no widespread pattern of consistent decline in calcification rates of massive Porites during the 20th century on reefs spanning an 11° latitudinal range in the southeast Indian Ocean off Western Australia. Increasing calcification rates on the high-latitude reefs contrast with the downward trajectory reported for corals on Australia's Great Barrier Reef and provide additional evidence that recent changes in coral calcification are responses to temperature rather than ocean acidification.     

番荔枝果皮提取物对鸡T细胞的影响研究

用鸡传染性喉气管炎SA2株弱毒疫苗免疫接种实验鸡后，分别用番荔枝果皮提取物和生理盐水注射试验组和对照组。在48、72和96小时采血分离白细胞，以鸡传染性喉气管炎标准毒做刺激剂，检查试验组和对照组淋巴细胞转化率。试验组的转化率明显高于对照组；数理统计说明试验组与对照组具有显著性差异。番荔枝果皮提取物对鸡的T细胞具有积极的作用。     

alpha-Naphthoflavone, a potent antiplatelet flavonoid, is mediated through inhibition of phospholipase C activity and stimulation of cyclic GMP formation

The aim of this study was to systematically examine the inhibitory mechanisms of the flavonoid alpha-naphthoflavone (alpha-NF) in platelet activation. In this study, alpha-NF concentration dependently (5-20 microM) inhibited platelet aggregation stimulated by agonists. alpha-NF (5 and 10 microM) inhibited intracellular Ca(2+) mobilization, phosphoinositide breakdown, and thromboxane A(2) formation stimulated by collagen (1 microg/mL) in human platelets. In addition, alpha-NF (5 and 10 microM) markedly increased levels of cyclic GMP and cyclic GMP-induced vasodilator-stimulated phosphoprotein (VASP) Ser(157) phosphorylation. Rapid phosphorylation of a platelet protein of Mr 47,000 (P47), a marker of protein kinase C activation, was triggered by phorbol-12,13-dibutyrate (60 nM). This phosphorylation was markedly inhibited by alpha-NF (5 and 10 microM). However, alpha-NF (5 and 10 microM) did not reduce the electron spin resonance (ESR) signal intensity of hydroxyl radicals in collagen (1 microg/mL)-activated platelets. These results indicate that the antiplatelet activity of alpha-NF may be involved in the following pathways. (1) alpha-NF may inhibit the activation of phospholipase C, followed by inhibition of phosphoinositide breakdown, protein kinase C activation, and thromboxane A(2) formation, thereby leading to inhibition of intracellular Ca(2+) mobilization. (2) alpha-NF also activated the formation of cyclic GMP, resulting in inhibition of platelet aggregation. These results strongly indicate that alpha-NF appears to represent a novel and potent antiplatelet agent for treatment of arterial thromboembolism.     

鸡腺胃型传支的疾病模型确定Ⅰ.临床症状及眼观病理变化规律

对1日龄雏鸡人工接种IBV腺胃型致病株(弱毒株),同时,在实验过程中,对鸡群人为地施以不同的应激因素,如降低温度、饥饿、不良通风和高密度饲养使鸡只感染发病.观察攻毒后的临床症状,同时定期随机剖检攻毒活鸡和病死鸡,观察眼观病理变化,并记录.鸡群表现畏寒,扎堆,不爱运动,呼吸有锣音,张口呼吸,采食和饮水明显减少,拉黄白色稀粪,发病中后期极度消瘦,鸡群发育极不整齐.腺胃肿胀、中后期萎缩,贫血,肺脏淤血,内脏痛风,肾脏尿酸盐沉积.结果表明:攻毒后4～5日开始出现临床症状,8～9日达到高峰,随后症状逐渐减轻.1天多以后,对照组也出现相似的临床症状及眼观病理变化.说明此病的传播性很强.     

Biological control of crystal texture: a widespread strategy for adapting crystal properties to function

Textures of calcite crystals from a variety of mineralized tissues belonging to organisms from four phyla were examined with high-resolution synchrotron x-ray radiation. Significant differences in coherence length and angular spread were observed between taxonomic groups. Crystals from polycrystalline skeletal ensembles were more perfect than those that function as single-crystal elements. Different anisotropic effects on crystal texture were observed for sea urchin and mollusk calcite crystals, whereas none was found for the foraminifer, Patellina, and the control calcite crystals. These results show that the manipulation of crystal texture in different organisms is under biological control and that crystal textures in some tissues are adapted to function. A better understanding of this apparently widespread biological phenomenon may provide new insights for improving synthetic crystal-containing materials.     

Orbital and millennial Antarctic climate variability over the past 800,000 years

A high-resolution deuterium profile is now available along the entire European Project for Ice Coring in Antarctica Dome C ice core, extending this climate record back to marine isotope stage 20.2, approximately 800,000 years ago. Experiments performed with an atmospheric general circulation model including water isotopes support its temperature interpretation. We assessed the general correspondence between Dansgaard-Oeschger events and their smoothed Antarctic counterparts for this Dome C record, which reveals the presence of such features with similar amplitudes during previous glacial periods. We suggest that the interplay between obliquity and precession accounts for the variable intensity of interglacial periods in ice core records.