Estradiol-induced protection against ischemia-induced heart mitochondrial damage and caspase activation is mediated by protein kinase G

We have previously reported that estradiol can protect heart mitochondria from the ischemia-induced mitochondrial permeability transition pore-related release of cytochrome c and subsequent apoptosis. In this study we investigated whether the effect of 17-beta-estradiol on ischemia-induced mitochondrial dysfunctions and apoptosis is mediated by activation of signaling protein kinases in a Langendorff-perfused rat heart model of stop-flow ischemia. We found that pre-perfusion of non-ischemic hearts with 100 nM estradiol increased the resistance of subsequently isolated mitochondria to the calcium-induced opening of mitochondrial permeability transition pore and this was mediated by protein kinase G. Loading of the hearts with estradiol prevented ischemia-induced loss of cytochrome c from mitochondria and respiratory inhibition and these effects were reversed in the presence of the inhibitor of Akt kinase, NO synthase inhibitor L-NAME, guanylyl cyclase inhibitor ODQ and protein kinase G inhibitor KT5823. Estradiol prevented ischemia-induced activation of caspases and this was also reversed by KT5823. These findings suggest that estradiol may protect the heart against ischemia-induced injury activating the signaling cascade which involves Akt kinase, NO synthase, guanylyl cyclase and protein kinase G, and results in blockage of mitochondrial permeability transition pore-induced release of cytochrome c from mitochondria, respiratory inhibition and activation of caspases.     

Relationships between Brucella ovis semen culture and various semen and serology parameters

Semen and blood samples from 154 rams from two Montana range flocks (Flock A, vaccinated for Brucella ovis ; Flock B, nonvaccinated) were evaluated to determine the relationship between Brucella ovis (B. ovis ) semen culture results and various semen and blood parameters. All rams utilized in this study exhibited no palpable ram epididymitis lesions. Thirteen and 25.6% of the rams tested in Flocks A and B, respectively, had positive B. ovis semen cultures. Only age of ram and ram condition scores differed (P<0.05) between flocks. No flock by semen culture interactions were detected (P>0.05) for any of the parameters evaluated. Age of ram, ram condition score, and spermatozoa rate from forward movement were unrelated (P>0.05) to B. ovis culture results. Rams with positive B. ovis semen cultures had lower sperm motility (P<0.05), higher percentage of abnormal spermatozoa cells (P<0.05), higher percentage of spermatozoa head abnormalities (P<0.01), lower percentage of live-normal cells (P<0.05), higher incidence of white blood cells in semen (P<0.01) and higher complement fixation (CF) titers (P<0.01).     

Photoperiod and pinealectomy do not affect cold-induced deposition of brown adipose tissue in the long-evans rat

Brown adipose tissue is a major thermogenic effector of cold-induced nonshivering thermogenesis. Previous studies indicate that melatonin and/or short photo-period are involved in the increase in brown fat deposition seen in certain cold-acclimated rodents. The present study was undertaken, in part, to determine whether the pineal is a necessary component in the cold-induced increase in thermogenic capacity characteristic of the cold-acclimated laboratory rat. Under a 12L:12D light cycle, pinealectomized rats did not differ from sham-operated rats in their ability to increase brown fat deposition in the cold (5 °C). Moreover, in a subsequent set of experiments performed at 9 °C, intact rats maintained at a short photoperiod (9L:15D) exhibited the same degree of brown fat hypertrophy/hyperplasia as did those kept at a long photoperiod (15L:9D). These data thus indicate that: (a) the intact pineal is not necessary for the cold-induced increase in brown adipose tissue occurring in the cold-acclimated rat; and (b) photoperiod does not significantly modulate the magnitude of this increase.     

Enhanced plant regeneration from microspore-derived embryos of Brassica napus by chilling,partial desiccation and age selection

Germination was readily induced in recalcitrant microspore-derived embryos of Brassica napus Topas when they were exposed to a period of chilling (9–12 days at 4°C) or partial desiccation (rapid or slow air drying) prior to germination. In general, embryos thirty-five days old had the highest germination rates as compared to younger or older ones. Populations of embryos were induced to germinate at a rate of over 90% under specific temperature, desiccation and age conditions. Comparisons to an embryogenic B. napus winter line, F346, are made.     

A simple, rapid and sensitive presence/absence detection test for bacteriophage in drinking water

R. ARMON AND Y. KOTT. 1993. A rapid, simple and sensitive direct bacteriophage presence detection method for 500 ml drinking water samples has been developed. The method includes a glass device consisting of a jar containing the water sample and an immersible probe filled with solidified soft agar containing bacterial host cells. Host bacteria in logarithmic phase were added to the experimental volume and the probe was submerged. The entire device was incubated in a water bath at 36C.
Plaques of somatic bacteriophage infecting Escherichia coli strain CN₁₃, could be detected within 3 h. Male-specific bacteriophages infecting E. coli F+ amp were detected within 6 h. Bacteriophage infecting the anaerobe Bacteroides fragilis subsp. fragilis HSP40 were detected after 8 h. Application of this device and the associated technique, enabled a one-step detection of 1 pfu of E. coli or Bact. fragilis specific bacteriophage in 500 ml drinking water samples.     

Sidestream smoke exposure enhances rapidly adapting receptor responses to substance P in young guinea pigs

Bonham, A. C., K. S. Kott, and J. P. Joad. Sidestreamsmoke exposure enhances rapidly adapting receptor responses to substance P in young guinea pigs. J. Appl.Physiol. 81(4): 1715-1722, 1996.We determinedthe effect of sidestream tobacco smoke (SS) exposure on responses oflung rapidly adapting receptors (RARs), peak tracheal pressure (Ptr),and arterial blood pressure (ABP) to substance P in young guinea pigs.Guinea pigs were exposed to SS or filtered air fromday 8 to days41-45 of life. They were then anesthetized andgiven three doses of intravenous substance P (1.56-4.94 nmol/kg).SS exposure augmented substance P-evoked increases in RAR activity(P = 0.029 by analysis of variance) but not substance P-evoked increases in peak Ptr or decreases in ABP.Neurokinin 1-receptor blockade (CP-96345, 400 nmol/kg) attenuatedsubstance P-evoked increases in RAR activity(P = 0.001) and ABP(P = 0.009) but not in peak Ptr(P = 0.06). Thus chronic exposure toSS in young guinea pigs exaggerates RAR responsiveness to substance P. The findings may help explain the increased incidence of airwayhyperresponsiveness and cough in children chronically exposed toenvironmental tobacco smoke.

     

Development of haploid cell lines from immature barley,Hordeum vulgare,embryos

Callus and suspension cell lines were derived from haploid barley embryos produced by the Bulbosum method. Embryos 1 to 2 mm long callused on medium containing a low concentration of 2,4-dichlorophenoxyacetic acid (2,4-D). Fast-growing nodular, beige callus (Type 1), slow-growing, light brown, watery callus (Type 2) and a dense, light yellow, nodular callus (Type 3) were recovered. Type 3 callus was embryogenic and was produced on embryos 1 to 2 mm in length. Although callus cultures gradually became polyploid, a small proportion of haploid cells was retained and the majority of regenerated plantlets were haploid. The organogenic potential of long-term (Type 1) callus cultures was generally low and decreased with time. Attempts to inducede novo shoot formation in Type 1 cultures were not successful.     

Preferential feeding behaviour of Daphnia magna

Preferential feeding behaviour by Daphnia magna was shown when Daphnia were fed on a mixture of ¹⁴C-labelled algae (Chlorella vulgaris or Scenedesmus quadricauda) and ³H-labelled bacteria (Escherichia coli). Daphnia consumption of bacteria was equal or higher in the presence of algae. On the other hand, in the presence of bacteria, algal consumption decreased by 40–70% compared to algal consumption in the absence of bacteria. ¹⁴C radioactive uptake was in good agreement with the chlorophyll content and demonstrates the preferential feeding behaviour of Daphnia.     

Resuspension studies in cylindrical microcosms: Effects of stirring velocity on the dynamics of redox sensitive elements in a coastal sediment

Effects of resuspension on the release of dissolved, redox sensitive elements (Fe, Mn) was studied in cylindrical microcosms. Effects from changing water stirring velocity in sediment pools were evaluated through measurements of pore water profiles of dissolved Mn, Fe and redox potential. Mn was a good natural marker to follow such effects. At current velocities below the threshold velocity for resuspension (37 cm s-1), Mn release rates to overlying water were 100 times higher compared to steady-state values. Pulse increases in Mn concentration were the result of convective currents inside flow chambers. These results were strongly supported by measurements of Eh profiles in the sediment pore water. Furthermore, impacts from increasing stirring velocity were found down to 1.9 cm depth below the resuspended layer of sediment.