Hormonally regulated programmed cell death in barley aleurone cells

Cell death was studied in barley (cv Himalaya) aleurone cells treated with abscisic acid and gibberellin. Aleurone protoplasts incubated in abscisic acid remained viable in culture for at least 3 weeks, but exposure to gibberellin initiated a series of events that resulted in death. Between 4 and 8 days after incubation in gibberellin, >70% of all protoplasts died. Death, which occurred after cells became highly vacuolated, was manifest by an abrupt loss of plasma membrane integrity followed by rapid shrinkage of the cell corpse. Hydrolysis of DNA began before death and occurred as protoplasts ceased production of alpha-amylase. DNA degradation did not result in the accumulation of discrete low molecular weight fragments. DNA degradation and cell death were prevented by LY83583, an inhibitor of gibberellin signaling in barley aleurone. We conclude that cell death in aleurone cells is hormonally regulated and is the final step of a developmental program that promotes successful seedling establishment.     

Bioactive sutures

With the first wave of bioactive sutures already in the marketplace, research is ongoing in the development of future products. Such sutures could potentially have not only antimicrobial activity but also anesthetic and antineoplastic functions. Some clinical trials have already been completed in Russia. This technology is likely to become commonplace. This article reviews the progress made to date in the development of this technology.     

Assessment of microsphere technique for measurement of capillary blood flow in random skin flaps in pigs

In this technical paper, we reviewed the theory and methodology of the radioactive microsphere technique for determination of cardiac output and regional blood flow. Furthermore, we described two experiments conducted to assess this technique for measurement of capillary blood flow in skin-flap research. Our experimental data thus far indicated that the radioactive microsphere technique provided highly reproducible measurements for determination of capillary blood flow in 4 X 10 cm acute and delayed random skin flaps constructed in pigs. The advantages and disadvantages of this laboratory technique were also discussed.     

Exercise induction of gut microbiota modifications in obese,non-obese and hypertensive rats

Background

Obesity is a multifactor disease associated with cardiovascular disorders such as hypertension. Recently, gut microbiota was linked to obesity pathogenesisand shown to influence the host metabolism. Moreover, several factors such as host-genotype and life-style have been shown to modulate gut microbiota composition. Exercise is a well-known agent used for the treatment of numerous pathologies, such as obesity and hypertension; it has recently been demonstrated to shape gut microbiota consortia. Since exercise-altered microbiota could possibly improve the treatment of diseases related to dysfunctional microbiota, this study aimed to examine the effect of controlled exercise training on gut microbial composition in Obese rats (n = 3), non-obese Wistar rats (n = 3) and Spontaneously Hypertensive rats (n = 3). Pyrosequencing of 16S rRNA genes from fecal samples collected before and after exercise training was used for this purpose.

Results

Exercise altered the composition and diversity of gut bacteria at genus level in all rat lineages. Allobaculum (Hypertensive rats), Pseudomonas and Lactobacillus (Obese rats) were shown to be enriched after exercise, while Streptococcus (Wistar rats), Aggregatibacter and Sutturella (Hypertensive rats) were more enhanced before exercise. A significant correlation was seen in the Clostridiaceae and Bacteroidaceae families and Oscillospira and Ruminococcus genera with blood lactate accumulation. Moreover, Wistar and Hypertensive rats were shown to share a similar microbiota composition, as opposed to Obese rats. Finally, Streptococcus alactolyticus, Bifidobacterium animalis, Ruminococcus gnavus, Aggregatibacter pneumotropica and Bifidobacterium pseudolongum were enriched in Obese rats.

Conclusions

These data indicate that non-obese and hypertensive rats harbor a different gut microbiota from obese rats and that exercise training alters gut microbiota from an obese and hypertensive genotype background.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-511) contains supplementary material, which is available to authorized users.     

Charge effect on the photoinactivation of Gram-negative and Gram-positive bacteria by cationic meso-substituted porphyrins

Background  

In recent times photodynamic antimicrobial therapy has been used to efficiently destroy Gram (+) and Gram (-) bacteria using cationic porphyrins as photosensitizers. There is an increasing interest in this approach, namely in the search of photosensitizers with adequate structural features for an efficient photoinactivation process. In this study we propose to compare the efficiency of seven cationic porphyrins differing in meso-substituent groups, charge number and charge distribution, on the photodynamic inactivation of a Gram (+) bacterium (Enterococcus faecalis) and of a Gram (-) bacterium (Escherichia coli). The present study complements our previous work on the search for photosensitizers that might be considered good candidates for the photoinactivation of a large spectrum of environmental microorganisms.     

Mitochondrial KATP channels in hindlimb remote ischemic preconditioning of skeletal muscle against infarction

We previously demonstrated in the pig that instigation of three cycles of 10 min of occlusion and reperfusion in a hindlimb by tourniquet application (approximately 300 mmHg) elicited protection against ischemia-reperfusion injury (infarction) in multiple distant skeletal muscles subsequently subjected to 4 h of ischemia and 48 h of reperfusion, but the mechanism was not studied. The aim of this project was to test our hypothesis that mitochondrial ATP-sensitive potassium (KATP) (mKATP) channels play a central role in the trigger and mediator mechanisms of hindlimb remote ischemic preconditioning (IPC) of skeletal muscle against infarction in the pig. We observed in the pig that hindlimb remote IPC reduced the infarct size of latissimus dorsi (LD) muscle flaps (8 x 13 cm) from 45 +/- 2% to 22 +/- 3% (n = 10; P < 0.05). The nonselective KATP channel inhibitor glibenclamide (0.3 mg/kg) or the selective mKATP channel inhibitor 5-hydroxydecanoate (5-HD, 5 mg/kg), but not the selective sarcolemmal KATP (sKATP) channel inhibitor HMR-1098 (3 mg/kg), abolished the infarct-protective effect of hindlimb remote IPC in LD muscle flaps (n = 10, P < 0.05) when these drugs were injected intravenously at 10 min before remote IPC. In addition, intravenous bolus injection of glibenclamide (1 mg/kg) or 5-HD (10 mg/kg) at the end of hindlimb remote IPC also abolished the infarct protection in LD muscle flaps (n = 10; P < 0.05). Furthermore, intravenous injection of the specific mKATPchannel opener BMS-191095 (2 mg/kg) at 10 min before 4 h of ischemia protected the LD muscle flap against infarction to a similar extent as hindlimb remote IPC, and this infarct-protective effect of BMS-191095 was abolished by intravenous bolus injection of 5-HD (5 mg/kg) at 10 min before or after intravenous injection of BMS-191095 (n = 10; P < 0.05). The infarct protective effect of BMS-191095 was associated with a higher muscle content of ATP at the end of 4 h of ischemia and a decrease in muscle neutrophilic myeloperoxidase activity at the end of 1.5 h of reperfusion compared with the time-matched control (n = 10, P < 0.05). These observations led us to conclude that mKATP channels play a central role in the trigger and mediator mechanisms of hindlimb remote IPC of skeletal muscle against infarction in the pig, and the opening of mKATP channels in ischemic skeletal muscle is associated with an ATP-sparing effect during sustained ischemia and attenuation of neutrophil accumulation during reperfusion.     

Vasodilator effect and mechanism of action of vascular endothelial growth factor in skin vasculature

Various laboratories have reported that local subcutaneous or subdermal injection of VEGF(165) at the time of surgery effectively attenuated ischemic necrosis in rat skin flaps, but the mechanism was not studied and enhanced angiogenesis was implicated. In the present study, we used the clinically relevant isolated perfused 6 x 16-cm pig buttock skin flap model to 1) test our hypothesis that VEGF(165) is a potent vasodilator and acute VEGF(165) treatment increases skin perfusion; and 2) investigate the mechanism of VEGF(165)-induced skin vasorelaxation. We observed that VEGF(165) (5 x 10(-16)-5 x 10(-11) M) elicited a concentration-dependent decrease in perfusion pressure (i.e., vasorelaxation) in skin flaps preconstricted with a submaximal concentration of norepinephrine (NE), endothelin-1, or U-46619. The VEGF(165)-induced skin vasorelaxation was confirmed using a dermofluorometry technique for assessment of skin perfusion. The vasorelaxation potency of VEGF(165) in NE-preconstricted skin flaps (pD(2) = 13.57 +/- 0.31) was higher (P < 0.05) than that of acetylcholine (pD(2) = 7.08 +/- 0.24). Human placental factor, a specific VEGF receptor-1 agonist, did not elicit any vasorelaxation effect. However, a specific antibody to VEGF receptor-2 (1 microg/ml) or a specific VEGF receptor-2 inhibitor (5 x 10(-6) M SU-1498) blocked the vasorelaxation effect of VEGF(165) in NE-preconstricted skin flaps. These observations indicate that the potent vasorelaxation effect of VEGF(165) in the skin vasculature is initiated by the activation of VEGF receptor-2. Furthermore, using pharmacological probes, we observed that the postreceptor signaling pathways of VEGF(165)-induced skin vasorelaxation involved activation of phospholipase C and protein kinase C, an increase in inositol 1,4,5-trisphosphate activity, release of the intra-cellular Ca(2+) store, and synthesis/release of endothelial nitric oxide, which predominantly triggered the effector mechanism of VEGF(165)-induced vasorelaxation. This information provides, for the first time, an important insight into the mechanism of VEGF(165) protein or gene therapy in the prevention/treatment of ischemia in skin flap surgery and skin ischemic diseases.