Electron microscopic study of immunoreactive LHRH perikarya with special reference to neuronal regulation

Summary In early postnatal rats, immunoreactive LHRH perikarya in the preoptic area were studied by light and electron microscopy. Synaptic junctions were found between the immunoreactive perikaryon or its process, and the immunonegative nerve fibers. The significance of these synapses is discussed in relation to possible mechanisms by which the activities of LHRH neurons are regulated.     

Ultrastructural localization of immunolabeled substance P and methionine-enkephalin-octapeptide in the surface layer of the dorsal horn of rat spinal cord

Summary A preembedding dual immunolabeling technique and electron microscopy were utilized to demonstrate the localization of immunoreactive substance P and methionine-enkephalin-octapeptide (Enk-8) in ultrathin sections of the surface layer (laminae I and II) of rat spinal dorsal horn. The immunoreaction of Enk-8 was visualized as goldtoned silver particles and that of substance P as diaminobenzidine reaction products. Axonal terminals with immunoreactive substance P, and also unlabeled axonal terminals, formed synaptic junctions with the perikarya and dendritic processes of Enk-8-containing neurons. Dendritic profiles immunolabeled for substance P were synaptically linked with unlabeled axons but not with Enk-8-positive ones. Furthermore, it was found that Enk-8 axons and substance P axons terminated synaptically in juxtaposition to one another on the same immunonegative dendrites. Among the Enk-8-containing neurons axonal profiles also appeared to be synaptically associated with immunoreactive Enk-8 dendritic processes.     

Rat choline acetyltransferase of the peripheral type differs from that of the common type in intracellular translocation

Choline acetyltransferase (ChAT), the synthesizing enzyme for acetylcholine, has been implicated to involve multiple isoforms of ChAT mRNA in several animals. Since these isoforms are mostly non-coding splice variants, only a homologous ChAT protein of about 68 kDa has been shown to be produced in vivo. Recent evidence indicates the existence of a protein coding splice variant of ChAT mRNA, which lacks exons 6-9 of the rat ChAT gene. The encoded protein was designated ChAT of a peripheral type (pChAT), because of its preferential expression in the peripheral nervous system as confirmed by Western blot and immunohistochemistry. However, functional significance of pChAT is unknown. To obtain a clue to this question, we examined a possible difference in intracellular trafficking between pChAT and the well-known ChAT of the common type (cChAT) using green fluorescent protein (GFP) in living human embryonic kidney cells. Confocal laser scanning microscopy revealed that pChAT-GFP was detectable in the cytoplasm but not in the nucleus, whereas cChAT-GFP was found in both cytoplasm and nucleus. Following treatment with leptomycin B, a nuclear export pathway inhibitor, pChAT-GFP became detectable in both cytoplasm and nucleus, indicating that pChAT can be translocated to the nucleus. In contrast, the leptomycin B treatment did not seem to affect the content of intranuclear cChAT-GFP. After incubation with protein kinase C inhibitors, enhanced accumulation of pChAT-GFP but not cChAT-GFP occurred in the nucleus. These results clearly indicate that pChAT varies from cChAT in intracellular transportation, probably reflecting the difference in physiological roles between pChAT and cChAT.     

Regulation of germination by targeted mutagenesis of grain dormancy genes in barley

High humidity during harvest season often causes pre-harvest sprouting in barley (Hordeum vulgare). Prolonged grain dormancy prevents pre-harvest sprouting; however, extended dormancy can interfere with malt production and uniform germination upon sowing. In this study, we used Cas9-induced targeted mutagenesis to create single and double mutants in QTL FOR SEED DORMANCY 1 (Qsd1) and Qsd2 in the same genetic background. We performed germination assays in independent qsd1 and qsd2 single mutants, as well as in two double mutants, which revealed a strong repression of germination in the mutants. These results demonstrated that normal early grain germination requires both Qsd1 and Qsd2 function. However, germination of qsd1 was promoted by treatment with 3% hydrogen peroxide, supporting the notion that the mutants exhibit delayed germination. Likewise, exposure to cold temperatures largely alleviated the block of germination in the single and double mutants. Notably, qsd1 mutants partially suppress the long dormancy phenotype of qsd2, while qsd2 mutant grains failed to germinate in the light, but not in the dark. Consistent with the delay in germination, abscisic acid accumulated in all mutants relative to the wild type, but abscisic acid levels cannot maintain long-term dormancy and only delay germination. Elucidation of mutant allele interactions, such as those shown in this study, are important for fine-tuning traits that will lead to the design of grain dormancy through combinations of mutant alleles. Thus, these mutants will provide the necessary germplasm to study grain dormancy and germination in barley.     

The coenzyme Q system in the classification of the ascosporogenous yeast genus Dekkera and the asporogenous yeast genus Brettanomyces

Fourteen strains of the genera Dekkera and Brettanomyces were examined for the coenzyme Q system. Without exception they contained the Q-9 system. The results are discussed from the taxonomic point of view.     

Interaction of plastocyanin with oligopeptides: effect of lysine distribution within the peptide

We synthesized and purified four oligopeptides containing four lysines (KKKK, GKKGGKK, KKGGGKK, and KGKGKGK) as models for the plastocyanin (PC) interacting site of cytochrome f. These peptides competitively inhibited electron transfer between cytochrome c and PC. The inhibitory effect increased as the peptide concentrations were increased. The association constants between PC and the peptides did not differ significantly (3500-5100 M(-1)), although the association constant of PC-KGKGKGK was a little larger than the constants between PC and other peptides. Changes in the absorption spectrum of PC were observed when the peptides were added to the PC solution: peaks and troughs were detected at about 460 and 630 nm and at about 560 and 700 nm, respectively, in the difference absorption spectra between the spectra with and without peptides. These changes were attributed to the structural change at the copper site of PC by interaction with the peptides. The structural change was most significant when tetralysine was used. These results show that binding of the oligopeptide to PC is slightly more efficient when lysines are distributed uniformly within the peptide, whereas the structural change of PC becomes larger when the lysines are close to each other within the peptide.     

Correlation between structure of the lactones and substrate specificity in enzyme-catalyzed polymerization for the synthesis of polyesters

Small-size (4-membered) and medium-size (5-, 6-, and 7-membered) unsubstituted lactones as well as unsubstituted macrolides (12 and 13 membered) were subjected to the ring-opening polymerization using the extracellular PHB depolymerase from Alcaligenes faecalis T1 (PhaZ(Afa)). The characteristic reactivities of the lactones were discussed based on a tertiary structure model of the active site of the PhaZ(Afa). With respect to the ring-size of the lactones, the 4-membered beta-propiolactone and 6-membered delta-valerolactone (delta-VL) showed the highest polymerization activity, and delta-VL seemed to be the upper size limit for the molecular recognition of the narrow active site cleft of PhaZ(Afa). On the other hand, epsilon-caprolactone, 11-undecanolide, and 12-dodecanolide, which showed excellent polymerization activities by lipases, were scarcely polymerized by PhaZ(Afa). This was ascribed to the difference in the recognition sites between PhaZ(Afa) and lipase. In addition, the effect of the substrate-binding domain of PhaZ(Afa) and the enantioselective ring-opening polymerization of (R,S)-beta-butyrolactone ((R,S)-beta-BL) were studied. The substrate-binding domain lacking PhaZ(Afa) showed higher reactivities than PhaZ(Afa) for the polymerization of the lactones and that a significant enantioselectivity was observed at the early stage of the polymerization of (R,S)-beta-BL to produce the (R)-enriched optically active poly(3-hydroxybutyrate).     

High Quality Topic Extraction from Business News Explains Abnormal Financial Market Volatility

Understanding the mutual relationships between information flows and social activity in society today is one of the cornerstones of the social sciences. In financial economics, the key issue in this regard is understanding and quantifying how news of all possible types (geopolitical, environmental, social, financial, economic, etc.) affects trading and the pricing of firms in organized stock markets. In this article, we seek to address this issue by performing an analysis of more than 24 million news records provided by Thompson Reuters and of their relationship with trading activity for 206 major stocks in the S&P US stock index. We show that the whole landscape of news that affects stock price movements can be automatically summarized via simple regularized regressions between trading activity and news information pieces decomposed, with the help of simple topic modeling techniques, into their “thematic” features. Using these methods, we are able to estimate and quantify the impacts of news on trading. We introduce network-based visualization techniques to represent the whole landscape of news information associated with a basket of stocks. The examination of the words that are representative of the topic distributions confirms that our method is able to extract the significant pieces of information influencing the stock market. Our results show that one of the most puzzling stylized facts in financial economies, namely that at certain times trading volumes appear to be “abnormally large,” can be partially explained by the flow of news. In this sense, our results prove that there is no “excess trading,” when restricting to times when news is genuinely novel and provides relevant financial information.