Zooplankton decline in the Černé Lake (Šumava Mountains,Bohemia) as reflected in the stratification of cladoceran remains in the sediment

Stratigraphy of cladoceran remains in the upper 18 cm of a sediment core from the Lake Černé was studied. The successive disappearance of Bosmina longispina, Daphnia longispina and Ceriodaphnia quadrangula from the upper layers of the sediment corresponds with our knowledge concerning the disappearance of these species from the open water.     

Partial restoration of impaired alpha1-adrenergic responsiveness in parotid cells of aged rats by S-adenosylmethionine treatment

The age related decrease in alpha₁-adrenergic stimulated inositol 1,4,5 trisphosphate (IP₃) production in parotid cells of aged rats can be partially restored by treatment with S-adenosylmethionine (SAM). This effect is completely blocked by S-adenosyl homocysteine (SAH) and occurs in association with an increase in the conversion of phosphatidylethanolamine to phosphatidylcholine and a decrease in membrane viscosity. In contrast, SAM treatment actually inhibits stimulated IP₃ production in cells of young rats. The membrane viscosity of these cells is lower than that of those from aged rats. Although conversion of phosphatidylethanolamine to phosphatidylcholine is enhanced, no further decrease in membrane viscosity is elicited in young cell preparations. These findings suggest that age changes in the membrane environment may result in impaired alpha₁-adrenergic signal transduction and that such alterations may be at least partially reversible by SAM treatment.     

Fatty acid composition of phospholipids of myelin and synaptosomal proteolipid complexes from vertebrate brain.

1. Fatty acid composition of five main phospholipids of vertebrate brain myelin and synaptosomal proteolipids and membranes was studied. 2. Higher content of monoenoic and lower content of saturated and polyenoic fatty acids was found to be characteristic of phospholipids from myelin and myelin proteolipids as compared to phospholipids from synaptosomal proteolipids and membranes of vertebrates (from fishes to mammalians). Fatty acid composition of phospholipids of proteolipid complexes and of the membranes, from which they were isolated, were found to be similar in various species studied. 3. Microviscosity was found to be higher in myelin as compared to synaptosomal membranes of frog Rana temporaria and in rabbit Lepus cuniculus. It appears to be due to the difference in proteolipid content and in lipid composition of myelin and synaptosomal membranes.     

13/14 translocation in a man with reproductive failure

Summary An inherited (maternal origin) 13/14 translocation with the nucleolus organizer regions eliminated and one centromere was found in an oligospermic man whose wife had had two spontaneous abortions. Meiotic studies revealed all stages of spermatogenesis with a trivalent configuration in diakinesis. Possible reasons for his subfertility and his mother's normal fertility are discussed.     

Analysis of replication region of the cryptic plasmid pAG20 from Acetobacter aceti 3620

The DNA sequence of small cryptic plasmid pAG20 in Acetobacter aceti was determined at 3064 bp with 51.6% GC pairs. The plasmid encoded a 186 amino acid protein which is important for plasmid replication in Gram-negative bacteria except Escherichia coli. Two 21 bp large direct repeat sequence 1 and two 13 bp direct repeat sequence 2 were determined in the regulation region upstream from gene encoded Rep protein. Vector pAG24 with kanamycin gene and two deletion derivatives pAG25 and pAG26 without rep gene from plasmid pAG20 were constructed. Plasmid pAG24 was replicated in a broad host range like E. coli, Acetobacter pasteurianus, A. aceti, Comanomonas spp., Serratia marcescens, and Shigella spp.     

Mitochondrial haplogroup N1a phylogeography,with implication to the origin of European farmers

Background  

Tracing the genetic origin of central European farmer N1a lineages can provide a unique opportunity to assess the patterns of the farming technology spread into central Europe in the human prehistory. Here, we have chosen twelve N1a samples from modern populations which are most similar with the farmer N1a types and performed the complete mitochondrial DNA genome sequencing analysis. To assess the genetic and phylogeographic relationship, we performed a detailed survey of modern published N1a types from Eurasian and African populations.     

Exosomes from neuronal stem cells may protect the heart from ischaemia/reperfusion injury via JAK1/2 and gp130

Myocardial infarction requires urgent reperfusion to salvage viable heart tissue. However, reperfusion increases infarct size further by promoting mitochondrial damage in cardiomyocytes. Exosomes from a wide range of different cell sources have been shown to activate cardioprotective pathways in cardiomyocytes, thereby reducing infarct size. Yet, it is currently challenging to obtain highly pure exosomes in quantities enough for clinical studies. To overcome this problem, we used exosomes isolated from CTX0E03 neuronal stem cells, which are genetically stable, conditionally inducible and can be produced on an industrial scale. However, it is unknown whether exosomes from neuronal stem cells may reduce cardiac ischaemia/reperfusion injury. In this study, we demonstrate that exosomes from differentiating CTX0E03 cells can reduce infarct size in mice. In an in vitro assay, these exosomes delayed cardiomyocyte mitochondrial permeability transition pore opening, which is responsible for cardiomyocyte death after reperfusion. The mechanism of MPTP inhibition was via gp130 signalling and the downstream JAK/STAT pathway. Our results support previous findings that exosomes from non-cardiomyocyte-related cells produce exosomes capable of protecting cardiomyocytes from myocardial infarction. We anticipate our findings may encourage scientists to use exosomes obtained from reproducible clinical-grade stocks of cells for their ischaemia/reperfusion studies.