Biochemische Untersuchungen über Vernalisation und Blütenbildung der Gerste

Ohne ZusammenfassungMit 15 TextabbildungenAuszug aus einer Dissertation der Naturwissenschaftlich-Philosophischen Fakultät der Justus Liebig-Universität, Gießen.     

Zur Genetik vonPetunia hybrida

Ohne ZusammenfassungTeil einer Dissertation, die bei der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Köln eingereicht wurde.     

Time-Wise Change in Neck Pain in Response to Rehabilitation with Specific Resistance Training: Implications for Exercise Prescription

Purpose

To determine the time-wise effect of specific resistance training on neck pain among industrial technicians with frequent neck pain symptoms.

Methods

Secondary analysis of a parallel-group cluster randomized controlled trial of 20 weeks performed at two large industrial production units in Copenhagen, Denmark. Women with neck pain >30 mm VAS (N = 131) were included in the present analysis. The training group (N = 77) performed specific resistance training for the neck/shoulder muscles three times a week, and the control group (N = 54) received advice to stay active. Participants of both groups registered neck pain intensity (0–100 mm VAS) once a week.

Results

Neck pain intensity was 55 mm (SD 23) at baseline. There was a significant group by time interaction for neck pain (F-value 2.61, P<0.001, DF = 19). Between-group differences in neck pain reached significance after 4 weeks (11 mm, 95% CI 2 to 20). The time-wise change in pain showed three phases; a rapid decrease in the training group compared with the control group during the initial 7 weeks, a slower decrease in pain during the following weeks (week 8–15), and a plateau during the last weeks (week 16–20). Adherence to training followed a two-phase pattern, i.e. weekly participation rate was between 70–86% during the initial 7 weeks, dropping towards 55–63% during the latter half of the training period.

Conclusion

Four weeks of specific resistance training reduced neck pain significantly, but 15 weeks is required to achieve maximal pain reduction. The time-wise change in pain followed a three-phase pattern with a rapid effect during the initial 7 weeks followed by a slower but still positive effect, and finally a plateau from week 15 and onwards. Decreased participation rate may explain the decreased efficacy during the latter phase of the intervention.     

Zn induces hyperpolarization by activation of a K channel and increases intracellular Ca and pH in sea urchin spermatozoa

Zinc (Zn²⁺) has been recently recognized as a crucial element for male gamete function in many species although its detailed mechanism of action is poorly understood. In sea urchin spermatozoa, Zn²⁺ was reported as an essential trace ion for efficient sperm motility initiation and the acrosome reaction by modulating intracellular pH (pH_i). In this study we found that submicromolar concentrations of free Zn²⁺ change membrane potential (Em) and increase the concentration of intracellular Ca²⁺ ([Ca²⁺]_i) and cAMP in Lytechinus pictus sperm. Our results indicate that the Zn²⁺ response in sperm of this species mainly involves an Em hyperpolarization caused by K⁺ channel activation. The pharmacological profile of the Zn²⁺-induced hyperpolarization indicates that the cGMP-gated K⁺ selective channel (tetraKCNG/CNGK), which is crucial for speract signaling, is likely a main target for Zn²⁺. Considering that Zn²⁺ also induces [Ca²⁺]_i fluctuations, our observations suggest that Zn²⁺ activates the signaling cascade of speract, except for an increase in cGMP, and facilitates sperm motility initiation upon spawning. These findings provide new insights about the role of Zn²⁺ in male gamete function.     

Modern Acinetobacter baumannii clinical isolates replicate inside spacious vacuoles and egress from macrophages

Multidrug-resistant Acinetobacter baumannii infections are increasing at alarming rates. Therefore, novel antibiotic-sparing treatments to combat these A. baumannii infections are urgently needed. The development of these interventions would benefit from a better understanding of this bacterium’s pathobiology, which remains poorly understood. A. baumannii is regarded as an extracellular opportunistic pathogen. However, research on Acinetobacter has largely focused on common lab strains, such as ATCC 19606, that have been isolated several decades ago. These strains exhibit reduced virulence when compared to recently isolated clinical strains. In this work, we demonstrate that, unlike ATCC 19606, several modern A. baumannii clinical isolates, including the recent clinical urinary isolate UPAB1, persist and replicate inside macrophages within spacious vacuoles. We show that intracellular replication of UPAB1 is dependent on a functional type I secretion system (T1SS) and pAB5, a large conjugative plasmid that controls the expression of several chromosomally-encoded genes. Finally, we show that UPAB1 escapes from the infected macrophages by a lytic process. To our knowledge, this is the first report of intracellular growth and replication of A. baumannii. We suggest that intracellular replication within macrophages may contribute to evasion of the immune response, dissemination, and antibiotic tolerance of A. baumannii.     

Photoperiod Regulates Lean Mass Accretion,but Not Adiposity,in Growing F344 Rats Fed a High Fat Diet

In this study the effects of photoperiod and diet, and their interaction, were examined for their effects on growth and body composition in juvenile F344 rats over a 4-week period. On long (16L:8D), relative to short (8L:16D), photoperiod food intake and growth rate were increased, but percentage adiposity remained constant (ca 3-4%). On a high fat diet (HFD), containing 22.8% fat (45% energy as fat), food intake was reduced, but energy intake increased on both photoperiods. This led to a small increase in adiposity (up to 10%) without overt change in body weight. These changes were also reflected in plasma leptin and lipid levels. Importantly while both lean and adipose tissue were strongly regulated by photoperiod on a chow diet, this regulation was lost for adipose, but not lean tissue, on HFD. This implies that a primary effect of photoperiod is the regulation of growth and lean mass accretion. Consistent with this both hypothalamic GHRH gene expression and serum IGF-1 levels were photoperiod dependent. As for other animals and humans, there was evidence of central hyposomatotropism in response to obesity, as GHRH gene expression was suppressed by the HFD. Gene expression of hypothalamic AgRP and CRH, but not NPY nor POMC, accorded with the energy balance status on long and short photoperiod. However, there was a general dissociation between plasma leptin levels and expression of these hypothalamic energy balance genes. Similarly there was no interaction between the HFD and photoperiod at the level of the genes involved in thyroid hormone metabolism (Dio2, Dio3, TSHβ or NMU), which are important mediators of the photoperiodic response. These data suggest that photoperiod and HFD influence body weight and body composition through independent mechanisms but in each case the role of the hypothalamic energy balance genes is not predictable based on their known function.     

In MMTV-Her-2/neu transgenic mammary tumors the absence of caveolin-1−/− alters PTEN and NHERF1 but not β-catenin expression

In a recent study, we have shown that in mammary tumors from mice lacking the Cav-1 gene, there are alterations in specific heat shock proteins as well as in tumor development. With this in mind, we have now investigated other proteins in the same mammary mouse tumor model (Her-2/neu expressing mammary tumors from Cav-1 wild type and Cav-1 null mice), to further comprehend the complex tumor-stroma mechanisms involved in regulating stress responses during tumor development. In this tumor model the cancer cells always lacked of Cav-1, so the KO influenced the Cav-1 in the stroma. By immunohistochemistry, we have found a striking co-expression of β-catenin and Her-2/neu in the tumor cells. The absence of Cav-1 in the tumor stroma had no effect on expression or localization of β-catenin and Her-2/neu. Both proteins appeared co-localized at the cell surface during tumor development and progression. Since Her-2/neu activation induces MTA1, we next evaluated MTA1 in the mouse tumors. Although this protein was found in numerous nuclei, the absence of Cav-1 did not alter its expression level. In contrast, significantly more PTEN protein was noted in the tumors lacking Cav-1 in the stroma, with the protein localized mainly in the nuclei. P-Akt levels were relatively low in tumors from both Cav-1 WT and Cav-1 KO mice. There was also an increase in nuclear NHERF1 expression levels in the tumors arising from Cav-1 KO mice. The data obtained in the MMTV-neu model are consistent with a role for Cav-1 in adjacent breast cancer stromal cells in modulating the expression and localization of important proteins implicated in tumor cell behavior.     

Effects of Ca- and Na-lignosulfonate on starch gelatinization and network formation

The interaction of lignosulfonates with starches was examined by microscopy and viscosity measurements. 8% starch dispersions with Ca- or Na-lignosulfonate, or with only Ca²⁺ or Na⁺, were heated to 97 °C and cooled to 50 °C in a Brabender Viscograph, the gelatinization was followed by light microscopy and image analysis, and the gel network formed after cooling to 4 °C was studied under the transmission electron microscope.

The lignosulfonates (2%) delayed the initial granule swelling in all starches (native maize, waxy maize and waxy barley). The presence of ions enhanced amylose leakage resulting in lower peak viscosity. The viscosity during cooling increased more with Ca-LS than with Na-LS. With a low lignosulfonate concentration the network formed after cooling was homogeneous with fine strands. With Na-lignosulfonate, as well as with Na⁺, the network connectivity deteriorated and spherical aggregates formed. Ca-lignosulfonate induced a network with thick strands, but with Ca²⁺ the strands became thinner.