The giant synapse of squid stellate ganglion is a chemical synapse where the transmitter substance is not known. The components of the ACh-system are present in squid nervous tissue in large quantities. However externally applied cholinergic drugs have no effect on junctional transmission. Using the Copper thiocholine method for electron microscopic cytochemistry the reaction product was found at the axolemmal surface, in the cisternae of the endoplasmic reticulum of neurons and occasionally between the infoldings of the sheat cells surounding the axons. Abundant deposits of end product are observed in the extracellular space in the proximity to junctional region. However, the localization of the cytochemical end product at the junctional region proper was observed frequently, but not consistently. Radiometric measurements of enzyme activity have revealed that neither specific inhibitors nor specific substrates generaly used for differentiation of cholinesterases in mammalian nervous tissue can be employed for differentiation of squid enzymes. Considering the permeability barriers imposed for external acetylcholine by cytoplasmic processes and the high enzyme activity of structures surrounding the giant synapse, the possibility that acetylcholine may still be a candidate for the missing transmitter is discussed. 相似文献
Population surname structure in northeastern Italy municipalities, in which small Slovenian-speaking groups are present, are compared with neighboring populations of both Italian and Slovenian nationality. In the early 20th century those municipalities were part of the Italian territory and underwent a massive Italianization process that led to the mutation of the original Slovenian surnames into a derived Italian form. In order to track surname relationships among the examined communities, two different similarity analyses were performed: the first using the surnames as they are recorded in the Italian and Slovenian official telephone directories, and the second restoring the Italianized Slovenian surnames to their original form and then recalculating the populations' similarity. Both comparisons evidence a separation that depends on nationality, which is less marked after restoring surnames to their original form. Geographical elements, older historical events, and socioeconomic traits allow interpretation of these results. 相似文献
How life arose on the primitive Earth is one of the biggest questions in science. Biomolecular emergence scenarios have proliferated in the literature but accounting for the ubiquity of oxidized (+?5) phosphate (PO43?) in extant biochemistries has been challenging due to the dearth of phosphate and molecular oxygen on the primordial Earth. A compelling body of work suggests that exogenous schreibersite ((Fe,Ni)3P) was delivered to Earth via meteorite impacts during the Heavy Bombardment (ca. 4.1–3.8 Gya) and there converted to reduced P oxyanions (e.g., phosphite (HPO32?) and hypophosphite (H2PO2?)) and phosphonates. Inspired by this idea, we review the relevant literature to deduce a plausible reduced phospholipid analog of modern phosphatidylcholines that could have emerged in a primordial hydrothermal setting. A shallow alkaline lacustrine basin underlain by active hydrothermal fissures and meteoritic schreibersite-, clay-, and metal-enriched sediments is envisioned. The water column is laden with known and putative primordial hydrothermal reagents. Small system dimensions and thermal- and UV-driven evaporation further concentrate chemical precursors. We hypothesize that a reduced phospholipid arises from Fischer–Tropsch-type (FTT) production of a C8 alkanoic acid, which condenses with an organophosphinate (derived from schreibersite corrosion to hypophosphite with subsequent methylation/oxidation), to yield a reduced protophospholipid. This then condenses with an α-amino nitrile (derived from Strecker-type reactions) to form the polar head. Preliminary modeling results indicate that reduced phospholipids do not aggregate rapidly; however, single layer micelles are stable up to aggregates with approximately 100 molecules.
Antiviral activities of known protease inhibitors were assayed in virus-infected cell cultures. Some members of the cystatin superfamily, in particular chicken cystatin, were able to block virus replication. In a binding assay, using purified components, chicken and human cystatin were able to bind poliovirus protease with affinities which were reflected in their relative antiviral potencies. Prospects for application of protease inhibitors in clinical viral infections are discussed. 相似文献
In this study we have compared the structure of surnames of Slovenian and German (Carinthian) minorities of northeastern Italy with other municipalities of the neighbourhood. The analysis has been carried out by using estimates of the similarities between populations and the topological representation obtained by them, as well as the spatial autocorrelation. On the whole, this research shows some distinctions which depend on the territorial geography, especially in the mountainous area. Moreover, movements of individuals in the limited zones of the plain are evident, probably due to socioeconomic conditions, the moving of the people and their change of dwelling. Finally, it is probable that different Slovenian dialects generated characteristic structures of surnames which were well preserved in the most peripherical municipalities of the territory. 相似文献
Findings from numerous studies suggest an association between low cholesterol levels and suicidal behavior in patients with different psychiatric diagnoses. The aims of this case-control study were to test whether cholesterol levels in male suicidal patients (N=20) with borderline personality disorder (BPD) are lower than in male non-suicidal patients (N=20) with BPD and male healthy control group (N=20), and to evaluate the influence of structured individual psychoanalytic psychotherapy on suicidal behavior. The groups were matched for age and body mass index (BMI). Results showed that serum cholesterol levels did not differ significantly between suicidal and non-suicidal BPD patients and healthy controls. The level of psychopathology (measured by Brief Psychiatric Rating Scale and Hamilton Depression Rating Scale) was significantly higher in the group of suicidal patients, which indicates the importance of evaluating particular clinical symptoms in BPD, in order to prevent suicidal behavior. Non-suicidal male patients suffering from BPD received more frequently structured individual psychoanalytic psychotherapy prior to the hospitalization than suicidal group. These results emphasized the role of this type of psychotherapy in preventing suicidal behavior in BPD patients. 相似文献