Training improves endothelium-dependent vasodilation in resistance vessels of patients with heart failure

Katz, Stuart D., Jeannette Yuen, Rachel Bijou, and ThierryH. LeJemtel. Training improves endothelium-dependent vasodilation in resistance vessels of patients with heart failure.J. Appl. Physiol. 82(5):1488-1492, 1997.The effects of physical training onendothelium-dependent vasodilation in skeletal muscle resistance vessels were investigated in patients with heart failure. Forearm bloodflows(ml · min¹ · 100 ml¹) in response tobrachial arterial administration of acetylcholine (5 × 10⁵ and 5 × 10⁴ M at 1 ml/min) andnitroglycerin (5 × 10⁶ and 5 × 10⁵ M at 1 ml/min) weredetermined by strain-gauge venous occlusion plethysmography before andafter 8 wk of daily handgrip exercise in 12 patients with chronic heartfailure. After 8 wk of daily handgrip exercise, the vasodilatoryresponses to acetylcholine significantly increased from pretrainingvalues, i.e., 16.6 ± 2.0 vs. 8.6 ± 1.3 ml · min¹ · 100 ml¹(P < 0.05) and 27.5 ± 1.5 vs. 14.6 ± 1.7 ml · min¹ · 100 ml¹(P < 0.05), respect- ively,whereas the vasodilatory responses to nitroglycerin did notchange. Handgrip exercise training appears to specificallyenhance endothelium-dependent vasodilation in the forearm skeletalmuscle circulation of patients with heart failure.

     

Homology-based double-strand break-induced genome engineering in plants

Key message

This review summarises the recent progress in DSB-induced gene targeting by homologous recombination in plants. We are getting closer to efficiently inserting genes or precisely exchanging single amino acids.

Abstract

Although the basic features of double-strand break (DSB)-induced genome engineering were established more than 20 years ago, only in recent years has the technique come into the focus of plant biologists. Today, most scientists apply the recently discovered CRISPR/Cas system for inducing site-specific DSBs in genes of interest to obtain mutations by non-homologous end joining (NHEJ), which is the prevailing and often imprecise mechanism of DSB repair in somatic plant cells. However, predefined changes like the site-specific insertion of foreign genes or an exchange of single amino acids can be achieved by DSB-induced homologous recombination (HR). Although DSB induction drastically enhances the efficiency of HR, the efficiency is still about two orders of magnitude lower than that of NHEJ. Therefore, significant effort have been put forth to improve DSB-induced HR based technologies. This review summarises the previous studies as well as discusses the most recent developments in using the CRISPR/Cas system to improve these processes for plants.

     

Physiological Concentration of Exogenous Lactate Reduces Antimycin A Triggered Oxidative Stress in Intestinal Epithelial Cell Line IPEC-1 and IPEC-J2 In Vitro

Weaning triggers an adaptation of the gut function including luminal lactate generation by lactobacilli, depending on gastrointestinal site. We hypothesized that both lactobacilli and lactate influence porcine intestinal epithelial cells. In vivo experiments showed that concentration of lactate was significantly higher in gastric, duodenal and jejunal chyme of suckling piglets compared to their weaned counterparts. In an in vitro study we investigated the impact of physiological lactate concentration as derived from the in vivo study on the porcine intestinal epithelial cells IPEC-1 and IPEC-J2. We detected direct adherence of lactobacilli on the apical epithelial surface and a modulated F-actin structure. Application of lactobacilli culture supernatant alone or lactate (25 mM) at low pH (pH 4) changed the F-actin structure in a similar manner. Treatment of IPEC cultures with lactate at near neutral pH resulted in a significantly reduced superoxide-generation in Antimycin A-challenged cells. This protective effect was nearly completely reversed by inhibition of cellular lactate uptake via monocarboxylate transporter. Lactate treatment enhanced NADH autofluorescence ratio (F_cytosol/F_nucleus) in non-challenged cells, indicating an increased availability of reduced nucleotides, but did not change the overall ATP content of the cells. Lactobacilli-derived physiological lactate concentration in intestine is relevant for alleviation of redox stress in intestinal epithelial cells.     

Attack of the clones: reproductive interference between sexuals and asexuals in the Crepis agamic complex

Negative reproductive interactions are likely to be strongest between close relatives and may be important in limiting local coexistence. In plants, interspecific pollen flow is common between co‐occurring close relatives and may serve as the key mechanism of reproductive interference. Agamic complexes, systems in which some populations reproduce through asexual seeds (apomixis), while others reproduce sexually, provide an opportunity to examine effects of reproductive interference in limiting coexistence. Apomictic populations experience little or no reproductive interference, because apomictic ovules cannot receive pollen from nearby sexuals. Oppositely, apomicts produce some viable pollen and can exert reproductive interference on sexuals by siring hybrids. In the Crepis agamic complex, sexuals co‐occur less often with other members of the complex, but apomicts appear to freely co‐occur with one another. We identified a mixed population and conducted a crossing experiment between sexual diploid C. atribarba and apomictic polyploid C. barbigera using pollen from sexual diploids and apomictic polyploids. Seed set was high for all treatments, and as predicted, diploid–diploid crosses produced all diploid offspring. Diploid–polyploid crosses, however, produced mainly polyploidy offspring, suggesting that non‐diploid hybrids can be formed when the two taxa meet. Furthermore, a small proportion of seeds produced in open‐pollinated flowers was also polyploid, indicating that polyploid hybrids are produced under natural conditions. Our results provide evidence for asymmetric reproductive interference, with pollen from polyploid apomicts contributing to reduce the recruitment of sexual diploids in subsequent generations. Existing models suggest that these mixed sexual–asexual populations are likely to be transient, eventually leading to eradication of sexual individuals from the population.     

Population Differences in Postural Response Strategy Associated with Exposure to a Novel Continuous Perturbation Stimuli: Would Dancers Have Better Balance on a Boat?

Central or postural set theory suggests that the central nervous system uses short term, trial to trial adaptation associated with repeated exposure to a perturbation in order to improve postural responses and stability. It is not known if longer-term prior experiences requiring challenging balance control carryover as long-term adaptations that influence ability to react in response to novel stimuli. The purpose of this study was to determine if individuals who had long-term exposure to balance instability, such as those who train on specific skills that demand balance control, will have improved ability to adapt to complex continuous multidirectional perturbations. Healthy adults from three groups: 1) experienced maritime workers (n = 14), 2) novice individuals with no experience working in maritime environments (n = 12) and 3) individuals with training in dance (n = 13) participated in the study. All participants performed a stationary standing task while being exposed to five 6 degree of freedom motions designed to mimic the motions of a ship at sea. The balance reactions (change-in-support (CS) event occurrences and characteristics) were compared between groups. Results indicate dancers demonstrated significantly fewer CS events than novices during the first trial, but did not perform as well as those with offshore experience. Linear trend analyses revealed that short-term adaptation across all five trials was dependent on the nature of participant experience, with dancers achieving postural stability earlier than novices, but later than those with offshore experience. These results suggest that long term previous experiences also have a significant influence on the neural control of posture and balance in the development of compensatory responses.     

Assessing the In Situ Fertilization Status of Two Marine Copepod Species,Temora longicornis and Eurytemora herdmani; How Common Are Unfertilized Eggs in Nature?

We utilized an egg staining technique to measure the in situ fertilization success of two marine copepod species, Temora longicornis and Eurytemora herdmani from May to October 2008 in coastal Maine and correlated fertilization success with environmental conditions in their habitat. T. longicornis is a free spawning species that releases eggs into the ambient seawater after mating. In contrast, E. herdmani carries eggs in an egg sac until they hatch. The proportion of fertilized eggs within E. herdmani egg sacs was significantly higher than the freely spawned clutches of T. longicornis. This may be a result of the asymmetrical costs associated with carrying vs. spawning unfertilized eggs. T. longicornis frequently laid both fertilized and unfertilized eggs within their clutch. T. longicornis fertilization was negatively associated with chlorophyll concentration and positively associated with population density in their local habitat. The fertilization status of E. herdmani egg sacs was high throughout the season, but the proportion of ovigerous females was negatively associated with an interaction between predators and the proportion of females in the population. This study emphasizes that, in addition to population level processes, community and ecosystem level processes strongly influence the fertilization success and subsequent productivity of copepods.     

The Reconfiguring Self

This essay presents a theory about cultural systems of self. It counters disclaimers as to the possibility of building cross-culturally valid theory, often taken to be the intellectual outcome of postmodernism. Nonetheless, such theory is a logical descendant of the postmodern project, predicating multiple selves and multiple constructions of social reality. It offers an explanatory framework for conceptions of personhood that are loosely interconnected and only partially and problematically shared between culture members.     

A fluorescent substrate for the assay of phosphatidylinositol-specific phospholipase C: 4-(1-pyreno)butylphosphoryl-1-myo-inositol

Racemic 4-(1-pyreno)butylphosphoryl-1-myo-inositol was synthesized from a pentaprotected inositol-1-dimethylphosphite by phosphite coupling with 4-(1-pyreno)butanol. It is a good substrate for a very sensitive assay of phosphatidylinositol-specific phospholipase C.