猫后内侧上雪氏区视神经元对运动棒反应的取向和方向特征

猫后内侧上雪区（ｐｏｓｔｅｒｏｍｅｄｉａｌｌａｔｅｒａｌｓｕｐｒａｓｙｌｖｉａｎａｒｅａ,ＰＭＬＳ）的绝大多数神经元（１７１／２００）对运动棒的取向调谐,６２％（１２４／２００）细胞的取向调谐宽度（半高波宽）小于９０°：按方向选择性和取向选择性可分辨出几类特征明显的细胞类型：１、强取向和强方向选择性细胞;２、强取向调谐的双向选择细胞;３、弱取向调谐的强方向选择细胞;４、无取向无方向选择性细胞;以及５、特征不明显的或中间类型细胞。它们与最近光学记录揭示的鹰猴中颞叶视区（ｍｉｄｄｌｅｔｅｍｐｏｒａｌｖｉｓｕａｌａｒｅａ,ＭＴ）的组织有很好的吻合。     

灰杨克隆繁殖、自身养分与土壤养分季节变化及其耦合关系的林缘——林内差异

阐明灰杨(Populus pruinosa Schrenk)克隆特征变化及受外界环境影响,是增强灰杨林生态服务功能的基础。本研究在中国新疆塔里木河上游灰杨河岸林,沿垂直河道方向在林缘(距河道200 m)、林内(距河道400 m)生境设置样方,于2014年4～10月,每隔20天调查两生境不定芽、未出土和出土克隆分株数量,测定横走侧根及土壤养分含量。结果表明:(1)横走侧根全氮、全磷、全钾、有机碳含量的变化趋势与不定芽和未出土分株数在4～6月逐渐增加、7～10月逐渐减少变化趋势基本一致,与土壤有机质、碱解氮、速效磷及速效钾含量在4～6月逐渐升高或保持最高水平,在7～10月逐渐降低的变化趋势同步;横走侧根碳氮比在4～6月初逐渐降低,随后呈现增大又减小的趋势;氮磷比在4～6月逐渐减小,7月显著减小后逐渐增大(林缘)或基本保持不变(林内)。(2)不论是林缘还是林内,不定芽数量受到横走侧根全氮和氮磷比的影响,未出土分株数受到横走侧根全氮、有机碳含量、碳氮比的影响;林缘不定芽数量与土壤有机质、碱解氮及速效钾含量相关紧密,未出土分株数与土壤碱解氮和速效磷显著相关,土壤养分也与横走侧根全氮、碳氮比、氮磷比紧密相关,而在林内受到土壤养分影响的主要是横走侧根全氮和氮磷比。(3)林内的不定芽、未出土及出土克隆分株数量显著低于林缘,土壤养分含量通过影响横走侧根养分含量而影响不定芽、未出土分株、出土分株数量。灰杨是杨属为数不多的国家保护植物,具有重要的生态服务功能,我们的结果对基于克隆繁殖的灰杨林保护策略提供基础数据支持。     

电刺激杏仁复合体诱发心律失常及其下行神经通路的初步探讨

电刺激杏仁复合体能诱发心律失常。心律失常的类型为心动过缓伴室性或结性期外收缩。刺激杏仁复合体不同亚核均能诱发心律失常,不同类型的心律失常在核内具有相应的代表点。心律失常发作与杏仁局部区域诱发的爆发性后放电有关。推测杏仁复合体内神经元过度激活可能通过杏仁-迷走神经运动背核及杏仁-下丘脑外侧区等通路下行,使心率减慢、房室传导阻滞而导致心律失常。     

Horizontal gene transfer accelerates genome innovation and evolution

Horizontal gene transfer (HGT) spreads genetic diversity by moving genes across species boundaries. By rapidly introducing newly evolved genes into existing genomes, HGT circumvents the slow step of ab initio gene creation and accelerates genome innovation. However, HGT can only affect organisms that readily exchange genes (exchange communities). In order to define exchange communities and understand the internal and external environmental factors that regulate HGT, we analyzed approximately 20,000 genes contained in eight free-living prokaryotic genomes. These analyses indicate that HGT occurs among organisms that share similar factors. The most significant are genome size, genome G/C composition, carbon utilization, and oxygen tolerance.     

The most prevalent genetic cause of ALS-FTD,C9orf72 synergizes the toxicity of ATXN2 intermediate polyglutamine repeats through the autophagy pathway

The most common genetic cause for amyotrophic lateral sclerosis and frontotemporal dementia (ALS-FTD) is repeat expansion of a hexanucleotide sequence (GGGGCC) within the C9orf72 genomic sequence. To elucidate the functional role of C9orf72 in disease pathogenesis, we identified certain molecular interactors of this factor. We determined that C9orf72 exists in a complex with SMCR8 and WDR41 and that this complex acts as a GDP/GTP exchange factor for RAB8 and RAB39, 2 RAB GTPases involved in macroautophagy/autophagy. Consequently, C9orf72 depletion in neuronal cultures leads to accumulation of unresolved aggregates of SQSTM1/p62 and phosphorylated TARDBP/TDP-43. However, C9orf72 reduction does not lead to major neuronal toxicity, suggesting that a second stress may be required to induce neuronal cell death. An intermediate size of polyglutamine repeats within ATXN2 is an important genetic modifier of ALS-FTD. We found that coexpression of intermediate polyglutamine repeats (30Q) of ATXN2 combined with C9orf72 depletion increases the aggregation of ATXN2 and neuronal toxicity. These results were confirmed in zebrafish embryos where partial C9orf72 knockdown along with intermediate (but not normal) repeat expansions in ATXN2 causes locomotion deficits and abnormal axonal projections from spinal motor neurons. These results demonstrate that C9orf72 plays an important role in the autophagy pathway while genetically interacting with another major genetic risk factor, ATXN2, to contribute to ALS-FTD pathogenesis.     

A Historical Perspective for the Catalytic Reaction Mechanism of Glycosidase; So As to Bring about Breakthrough in Confusing Situation

Various catalytic reaction models have been proposed as the reaction mechanisms of glycosidases, but a reasonable and unitary model capable of interpreting both “inverting” and “retaining” glycosidase reactions remains to be established. As for the models proposed to date, the nucleophilic displacement mechanism and the oxocarbenium ion intermediate mechanism are widely known, but recently the former is widely accepted, and so the general tendency of world opinion appears to favor it. This reaction model, however, is considered to comprise some inconsistencies that cannot be neglected from the viewpoint of reactivity in organic chemistry. While the nucleophilic displacement mechanism is often applied to reactions of glycosidases, it appears unlikely that such reactions actually occur. This review argues that the oxocarbenium ion intermediate reaction mechanism is more rational than the nucleophilic displacement reaction mechanism, as the action mode of glycosidases and related enzymes.     

R-Loop Mediated trans Action of the APOLO Long Noncoding RNA

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Chemical reactivity and uses of 1-phenyl-3-methyl-5-pyrazolone (PMP), also known as edaravone

1-Phenyl-3-methyl-5-pyrazolone is a reagent, known as PMP, used to derivatize monosaccharides for the study of polysaccharides composition and structure, and for the dosage of carbohydrates in complex media. The same molecule is also known as edaravone, a drug approved for the treatment of stroke and amyotrophic lateral sclerosis. It is also a reactive molecule susceptible to form stable adducts with aromatic aldehydes, such as formylpterin and vanillin. In addition, the molecule serves as a scaffold to design of edaravone analogs and drug conjugates, with various pharmacological properties (antioxidant, anticancer, antiviral). We have analyzed the multiple usages of PMP/edaravone to highlight the reactivity of the molecule and its wide range of applications. This phenyl-pyrazolone compound, considered by many as a biochemical reagent and by other as a clinically useful drug, has not yet revealed the full extent of its capacities and benefits.     

Comparative innervation of cephalic photophores of the loosejaw dragonfishes (Teleostei: Stomiiformes: Stomiidae): Evidence for parallel evolution of long‐wave bioluminescence

Four genera of the teleost family Stomiidae, the loosejaw dragonfishes, possess accessory cephalic photophores (AOs). Species of three genera, Aristostomias, Malacosteus, and Pachystomias, are capable of producing far‐red, long‐wave emissions (>650nm) from their AOs, a character unique among vertebrates. Aristostomias and Malacosteus posses a single far‐red AO, while Pachystomias possesses anterior and posterior far‐red AOs, each with smaller separate photophores positioned in their ventral margins. The purpose of this study was to establish the primary homology of the loosejaw AOs based on topological similarity of cranial nerve innervation, and subject these homology conjectures to tests of congruence under a phylogenetic hypothesis for the loosejaw dragonfishes. On the basis of whole‐mount, triple‐stained specimens, innervation of the loosejaw AOs is described. The AO of Aristostomias and the anterior AO of Pachystomias are innervated by the profundal ramus of the trigeminal (Tpr), while the far‐red AO of Malacosteus and a small ventral AO of Pachystomias are innervated by the maxillary ramus of the trigeminal (Tmx). The largest far‐red AO of Pachystomias, positioned directly below the orbit, and the short‐wave AO of Photostomias are innervated by a branch of the mandibular ramus of the trigeminal nerve. Conjectures of primary homology drawn from these neuroanatomical similarities were subjected to tests of congruence on a phylogeny of the loosejaws inferred from a reanalysis of a previously published morphological dataset. Optimized for accelerated transformation, the AO innervated by the Tpr appears as a single transformation on the new topology, thereby establishing secondary homology. The AOs innervated by the Tmd found in Pachystomias and Photostomias appear as two transformations in a reconstruction on the new topology, a result that rejects secondary homology of this structure. The secondary homology of AOs innervated by the Tmx found in Malacosteus and Pachystomias is rejected on the same grounds. Two short‐wave cephalic photophores present in all four genera, the suborbital (SO) and the postorbital (PO), positioned in the posteroventral margin of the orbit and directly posterior to the orbit, respectively, are innervated by separate divisions of the Tmd. The primary homologies of the loosejaw PO and SO across loosejaw taxa are proposed on the basis of similar innervation patterns. Because of dissimilar innervation of the loosejaw SO and SO of basal stomiiforms, primary homology of these photophores cannot be established. Because of similar function and position, the PO of all other stomiid taxa is likely homologous with the loosejaw PO. Nonhomology of loosejaw long‐wave photophores is corroborated by previously published histological evidence. The totality of evidence suggests that the only known far‐red bioluminescent system in vertebrates has evolved as many as three times in a closely related group of deep‐sea fishes. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.     

Tissue-selective regulation of protein homeostasis and unfolded protein response signalling in sporadic ALS

Amyotrophic lateral sclerosis (ALS) is a disorder that affects motor neurons in motor cortex and spinal cord, and the degeneration of both neuronal populations is a critical feature of the disease. Abnormalities in protein homeostasis (proteostasis) are well established in ALS. However, they have been investigated mostly in spinal cord but less so in motor cortex. Herein, we monitored the unfolded protein (UPR) and heat shock response (HSR), two major proteostasis regulatory pathways, in human post-mortem tissue derived from the motor cortex of sporadic ALS (SALS) and compared them to those occurring in spinal cord. Although the UPR was activated in both tissues, specific expression of select UPR target genes, such as PDIs, was observed in motor cortex of SALS cases strongly correlating with oligodendrocyte markers. Moreover, we found that endoplasmic reticulum-associated degradation (ERAD) and HSR genes, which were activated predominately in spinal cord, correlated with the expression of neuronal markers. Our results indicate that proteostasis is strongly and selectively activated in SALS motor cortex and spinal cord where subsets of these genes are associated with specific cell type. This study expands our understanding of convergent molecular mechanisms occurring in motor cortex and spinal cord and highlights cell type–specific contributions.