Effects of disuse on the function of fragmented sarcoplasmic reticulum of rabbit M. gastrocnemius

A preparation method has been described to obtain a relatively pure and functionally intact fragmented sarcoplasmic reticulum (SR) vesicles fraction from normal and atrophied muscles. Purified SR preparations from rabbit gastrocnemius muscle atrophied by disuse showed similar protein composition (gel electrophoresis; Laemmli 1970) and similar vanadate induced crystallization (Dux and Martonosi 1983) properties of Ca2+-ATPase as those of control preparations. In the early period of atrophy (1-2 weeks) both the Ca2+-ATPase activity and Ca2+ uptake showed a 2-3-fold increase (from 3.42 +/- 0.24 to 7.34 +/- 0.25 mumol Pi X mg-1 prot X min-1 and from 1.26 +/- 0.10 to 3.36 +/- 0.22 mumol/l Ca2+ X min-1 X mg-1 prot. respectively).     

The role of protein kinases and protein phosphatases in the regulation of cardiac sarcoplasmic reticulum function

Summary Canine cardiac sarcoplasmic reticulum is phosphorylated by adenosine 3,5-monophosphate (cAMP)-dependent and by calcium · calmodulin-dependent protein kinases on a 27 000 proteolipid, called phospholamban. Both types of phosphorylation are associated with an increase in the initial rates of Ca²⁺ transport by SR vesicles which reflects an increased turnover of elementary steps of the calcium ATPase reaction sequence. The stimulatory effects of the protein kinases on the calcium pump may be reversed by an endogenous protein phosphatase, which can dephosphorylate both the CAMP-dependent and the calcium · calmodulin-dependent sites on phospholamban. Thus, the calcium pump in cardiac sarcoplasmic reticulum appears to be under reversible regulation mediated by protein kinases and protein phosphatases.     

Ethanol Activates Maxi Ca2+-activated K+ Channels of Clonal Pituitary (GH3) Cells

The effect of ethanol on maxi Ca²⁺-activated K⁺ channels (BK channels) in GH3 pituitary tumor cells was investigated using single-channel recordings and focusing on intracellular signal transduction. In outside-out patches, ethanol caused a transient concentration-dependent increase of BK-channel activity. 30 mm (1.4‰) ethanol significantly increased mean channel open time and channel open probability by 26.3 ± 9% and 78.8 ± 10%, respectively; single-channel current amplitude was not affected by ethanol. The augmenting effect of ethanol was blocked in the presence of protein kinase C (PKC) inhibitors staurosporine, bisindolylmaleimide, and PKC (19–31) pseudosubstrate inhibitor as well as by AMP-PNP (5′-adenylylimidodiphosphate), a nonhydrolyzable ATP-analogue, but not by the phospholipase C blocker U-73122. Phosphatase inhibitors microcystin-LR and okadaic acid promoted the ethanol effect. The blocking effect was released at higher concentrations of ethanol (100 mm) suggesting a second site of action or a competition between blockers and ethanol. Our results suggest that the effect of ethanol on BK-channels is mediated by PKC stimulation and phosphorylation of the channels which increases channel activity and hence may influence action potentials duration and hormone secretion. Received: 24 July 1996/Revised: 27 December 1996     

The effect of the alpha 2-HS-glycoprotein on the mitogen-induced lymphoblastic transformation and IL-2 production

Authors investigated the in vitro effect of alpha 2-HS-glycoprotein on the lymphoblastic transformation and interleukin-2 production. The observations were made on the peripheral blood lymphocytes of healthy persons, on those of women taking oral contraceptives and on those of patients with systemic lupus erythematosus. The alpha 2-HS-glycoprotein inhibited the mitogen responses both in physiologic and in the halved concentrations. The inhibition of the interleukin-2 production seemed less remarkable.     

Hyaluronan bound mature sperm count (HB-MaSC) is a more informative indicator of fertility than conventional sperm parameters: Correlations with Body Mass Index (BMI)

The relationship between overweight and male fertility is well studied, still the correlation of obesity and decreased sperm quality is a subject to debate. The widely used conventional spermatological examinations alone seem to be inadequate to assess fertilization potential. Hyaluronan Binding Assay (HBA^®) is one of the available validated tests that allows the functional examination of sperm. Data of 72 male patients (mean age 33.9 (24–43) years) from infertile couples were analysed. Body Mass Index (BMI) determination, conventional semen analysis and HBA were performed. Additionally, a relatively new Hyaluronan Bound Matured Sperm Count (HB-MaSC) -index, first introduced by the authors in 2015, was calculated. This index reflects fertilization potential of sperm more precisely. With the increase of BMI, sperm count decreased significantly until about 25?kg/m², above 25?kg/m² no further decrease was observed, although sperm count remained permanently low. Greater body weight (in the 70–90?kg range) was observed to have a significant negative effect only on the progressive sperm motility. In addition to sperm concentration and motility, sperm fertilization potential is also negatively affected by obesity, but is irrespective of body weight, as evaluated using BMI + HB-MaSC linear regression analyses adjusted for age and weight. This correlation between male BMI and sperm fertilization potential – as opposed to the conventional correlations with sperm concentration or motility – appears to provide more helpful information in the identification of real capability for fertilization.     

Multiscale computational analysis of Xenopus laevis morphogenesis reveals key insights of systems-level behavior

Background  

Tissue morphogenesis is a complex process whereby tissue structures self-assemble by the aggregate behaviors of independently acting cells responding to both intracellular and extracellular cues in their environment. During embryonic development, morphogenesis is particularly important for organizing cells into tissues, and although key regulatory events of this process are well studied in isolation, a number of important systems-level questions remain unanswered. This is due, in part, to a lack of integrative tools that enable the coupling of biological phenomena across spatial and temporal scales. Here, we present a new computational framework that integrates intracellular signaling information with multi-cell behaviors in the context of a spatially heterogeneous tissue environment.     

Occurrence and transferability of β-lactam resistance inEnterobacteriaceae isolated inChildren's University Hospital in Bratislava

Occurrence and transferability of β-lactam resistance in 30 multi-resistantEscherichia coli, Klebsiella spp.,Enterobacter spp.,Pantoea agglomerans, Citrobacter freundii andSerratia marcescens strains isolated from children between 0 and 3 years of age is presented. The strains were resistant to ampicillin (30), cefoxitin (22), cefotaxime (30), ceftriaxone (30), ceftazidime (30) and aztreonam (28), but susceptible to cefepime (30) and imipenem (26). Twenty-eight of 30 isolates possessed a transferable resistance confirmed by conjugation and isolation of 79–89-kb plasmids. The β-lactam resistance was due to production of β-lactamases and ceftazidime proved to be stronger β-lactamase inductor than ceftriaxone. Twenty-five clinical isolates expressed transferable extended spectrum β-lactamases, and chromosomally encoded AmpC β-lactamase.     

The frequency of induced premature centromere division in human populations occupationally exposed to genotoxic chemicals

Premature (early) centromere division (PCD, i.e., the separation of centromeres during the prometaphase/metaphase of the mitotic cycle) seems to be a possible manifestation of chromosome instability in human chromosome-breakage syndromes. Chromosome instability also frequently occurs in the peripheral blood lymphocytes (PBL) of humans occupationally exposed to clastogenic agents, and is considered an etiologic factor of neoplastic diseases. In order to investigate the importance of PCD in cancer risk assessment, we studied the frequency of PCDs in PBL of 400 Hungarian subjects. The various groups comprised 188 control donors and 212 subjects occupationally exposed to different genotoxic chemicals, such as acrylonitrile (ACN) and/or dimethylformamide (DMF), benzene, cytostatic drugs, ethylene oxide (ETO), mixed exposure in the rubber industry, mixed organic solvents including CCl4, hot oil-mist, bitumen, and polychlorinated biphenyls (PCB). Data were compared with chromosomal aberration frequencies determined in the same samples. PCD yields are significantly higher in populations exposed to mixed chemicals, crude oil and cytostatic drugs, compared with controls. PCDs involving more than three chromosomes are also more frequent in ETO- and oil mist-exposed groups than in the others. The results indicate that the induction of PCDs is neither incidental nor artificial. As a consequence, we suggest that PCD can be developed into a new, exposure-related cytogenetic biomarker for a more adequate occupational cancer risk assessment. A further, follow-up epidemiological and cytogenetic investigation of PCD is in progress.     

Effects of in ovo treatment with PACAP antagonist on general activity, motor and social behavior of chickens

Pituitary adenylate cyclase activating polypeptide (PACAP) has been shown to influence nervous system development. The aim of the present study was to investigate the effects of in ovo treatment with the PACAP antagonist PACAP6-38 during embryonic life (E8 and E16) on motor activity and social behavior in chicken. Our results showed that a single injection of PACAP6-38 during the first half of embryonic life caused subtle transient changes in general behavior and motor control when compared to saline-treated controls. Increased activity and reduced anxiety were observed also in a novel environment at 2 days after hatching. However, most of these behavioral differences disappeared by 2 weeks. PACAP6-38-treatment during the first half of embryonic life resulted in markedly reduced social behavior, which was still present at 2 weeks of age. Treatment during the second half of embryonic life resulted in no behavioral differences between control and PACAP6-38-treated chicken. PACAP content in different brain areas was not different between control and PACAP6-38-treated chicken at 5 days or 3 weeks of age, but it decreased significantly with age in both groups. In summary, our results show that PACAP6-38 treatment at E8 caused transient changes in motor behavior, and long-lasting reduction in social behavior.     

Comparative mapping between<Emphasis Type="Italic"> Medicago sativa</Emphasis> and<Emphasis Type="Italic"> Pisum sativum</Emphasis>

Comparative genome analysis has been performed between alfalfa ( Medicago sativa) and pea ( Pisum sativum), species which represent two closely related tribes of the subfamily Papilionoideae with different basic chromosome numbers. The positions of genes on the most recent linkage map of diploid alfalfa were compared to those of homologous loci on the combined genetic map of pea to analyze the degree of co-linearity between their linkage groups. In addition to using unique genes, analysis of the map positions of multicopy (homologous) genes identified syntenic homologs (characterized by similar positions on the maps) and pinpointed the positions of non-syntenic homologs. The comparison revealed extensive conservation of gene order between alfalfa and pea. However, genetic rearrangements (due to breakage and reunion) were localized which can account for the difference in chromosome number (8 for alfalfa and 7 for pea). Based on these genetic events and our increasing knowledge of the genomic structure of pea, it was concluded that the difference in genome size between the two species (the pea genome is 5- to 10-fold larger than that of alfalfa) is not a consequence of genome duplication in pea. The high degree of synteny observed between pea and Medicago loci makes further map-based cloning of pea genes based on the genome resources now available for M. truncatula a promising strategy.Electronic Supplementary Material Supplementary material is available in the online version of this article at Communicated by W. R. McCombie