Cosinor analysis of diurnal changes of the reduced glutathione level in the blood, brain, liver and kidneys of mice, induced by ACTH administration

The influence of a single dose of ACTH(100 I.U. /kg body weight) on the diurnal rhythm of reduced glutathione (GSH) was studied in the blood and brain, liver and kidney homogenates of male mice. Cosinor analysis revealed that ACTH induces changes in the mean diurnal amount of GSH in the blood, brain, liver and kidneys. At the same time, GSH amplitudes in the blood and kidneys increased significantly, whereas in the case of brain and liver they decreased markedly. Moreover, it was found that ACTH induces a shift in GSH acrophases in the blood, brain, liver and kidneys as compared with the control values.     

DNA degradation at elevated temperatures after plasmid amplification in amino acid-starved Escherichia coli cells

Summary Amino acid starvation of Escherichia coli relA mutants may be used as a method for efficient plasmid DNA amplification. Here we demonstrate DNA degradation which occurs at elevated temperatures (42–43°C) after plasmid amplification in amino acid-starved bacteria. These results may explain the previously described low efficiency of plasmid DNA amplification at elevated temperatures.     

Interconversion of the salicylic acid signal and its glucoside in tobacco

Salicylic acid (SA) has been proposed to play a role in the induction of pathogenesis-related (PR) proteins and systemic acquired resistance (SAR) in tobacco. Since SA is rapidly converted to salicylic acid β-glucoside (SAG) in tobacco, we have attempted to assess the role of SAG in pathogenesis by application of chemically synthesized SAG to tobacco leaves. SAG was as active as SA in induction of PR-1 gene expression. This induction was preceded by a transient release of SA, which occurred in the extracellular spaces. The existence of a mechanism that releases SA from SAG suggests a possible role for SAG in SAR.     

Population genetic structure,parasite infection and somatic condition of pumpkinseed Lepomis gibbosus (Actinopterygii: Centrarchidae) in the Oder river basin

In Poland, distribution of non-native pumpkinseed Lepomis gibbosus (Centrarchidae) is strictly limited to the Oder river basin, where it was introduced in the early 20th century. Recently, several populations have been found in waterbodies adjacent to the Oder, particularly in its lower reaches. In this study, we compare the genetic relatedness of populations in the Oder basin with other European populations using nuclear (microsatellite) and mitochondrial (partial cytochrome c oxidase subunit I; cox1) markers. Microsatellite analysis indicated that four populations in the lower Oder form a separate cluster, while one in the middle Oder clustered with Danubian populations, from where probably having been introduced. Microsatellite data suggested that the lower Oder populations differ from other non-native European populations, making it impossible to estimate the source of introduction. Nevertheless, analysis of cox1 indicated that Oder pumpkinseeds belong to the same haplotype as the vast majority of European populations. Parasitological examination confirmed the presence of two North American species, the monogenean Onchocleidus dispar and trematode Posthodiplostomum centrarchi, in the lower Oder, both previously unknown in the region. Fifteen other parasite species were acquired, including glochidia of invasive Sinanodonta woodiana. In the middle Oder, parasite infection was more limited. Fish from the Gryfino Canal, considered one of the most invasive populations in Europe, showed the highest parasite abundance and diversity, and the highest somatic condition and growth rate due to warm water released from the Dolna Odra power plant. Our results highlight significant differences in somatic condition and parasite infection in long-established non-native pumpkinseed populations in the same river system, reflecting mainly environmental conditions.     

Seasonal changes in the number of neurocytes containing lipofuscin pigment in selected areas of the brain of Rana temporaria L

The number of neurocytes containing lipofuscin pigment (LEP) was determined in the nucleus infundibularis dorsalis (NID), the subfornical organ (SFO) and the medulla oblongata (MO) of the brain of sexually mature females and males of Rana temporaria L. approximately identical in length and age. The frogs were captured in their natural habitat in seven periods of the annual cycle. The number of LFP-positive neurocytes shows distinct seasonal variations in the analyzed areas. In general, neurocytes containing LFP were found in higher numbers during the winter months, and their significant drop was observed in summer. The results seem to suggest that cells containing LFP represent a certain kind of dynamic cellular system responding to various internal and/or external factors changing within a year.     

Influence of actinomycin-D on the diurnal rhythm of cytoplasmic RNA in the neurocytes of selected nuclei of mouse hypothalamus

The influence of a single dose of actinomycin-D (1 mg/kg body weight) on the diurnal rhythm of cytoplasmic RNA was studied in neurocytes of the supraoptic nucleus (SON), paraventricular nucleus (PVN), and arcuate nucleus (AN) by microspectrophotometer. Cosinor analysis of the obtained results revealed a disturbed diurnal rhythm of cytoplasmic RNA in the animals treated with actinomycin-D. The mean diurnal RNA content in the SON, PVN, and AN neurocytes decreased, the amplitude of diurnal fluctuation was reduced and the acrophase was shifted to earlier hours.