Osmotischer Druck und Ionengleichgewicht beim Blutegelmuskel

Zusammenfassung Es wurde das Verhalten des Blutegelrückenmuskels in Lösungen von verschiedenem osmotischen Druck und verschiedenem Ionengehalt untersucht. In reinen Zuckerlösungen sowie in reinen Kochsalzlösungen zeigt der Muskel einen von der Größe des osmotischen Druckes abhängigen Längszustand oder Tonus. Die Druck-Längenkurve zeigt in beiden Fällen einen Wendepunkt. Der in n/10-NaCl im Gleichgewicht befindliche Muskel erschlafft bei Herabsetzung des osmotischen Druckes bis zu einer Konzentration von n/20–n/30 und beginnt von da ab sich zu kontrahieren. In Na-freier Zuckerlösung liegt der Wendepunkt bei etwa molarer Konzentration, also bei etwa zehnmal so hohem osmotischen Druck. Erhöhung der Zuckerkonzentration führt zu Erschlaffung, Verminderung zu Kontraktion.Zusatz von Kalium zur NaCl-Lösung in einer die Isotonie nicht störenden Menge bewirkt eine wiederum von der Konzentration abhängige Längen- oder Tonusänderung, die gleichfalls einen Wendepunkt zeigt. Dieser liegt bei einer Konzentration von etwa n/250–n/200. Schwächere Konzentrationen bewirken eine Erschlaffung, stärkere eine Erhöhung des Muskeltonus. Kalzium wirkt in allen Konzentrationen erschlaffend. Es erscheint als Antagonist des Kaliums, wenn dieses kontrahierend wirkt, aber als Synergist, bei Kaliumkonzentrationen, die erschlaffend wirken.In O₂-reichem Medium bleibt die elektrische Reizbarkeit über 30 Stunden erhalten. Der Muskel zeigt ein großes Summationsvermögen, auch für einzeln unwirksame Reize. Die Erschlaffungsgeschwindigkeit steigt mit der Steilheit der Kontraktion. O₂-Mangel wirkt tonusvermindernd und erschlaffungsbeschleunigend. Hypotonie erhöht, Hypertonie vermindert die elektrische Reizbarkeit. Kalium hat wenig Einfluß, Kalzium erzeugt eine starke Herabsetzung der Reizbarkeit. Tonus und Reizkontraktion sind mithin von einander völlig unabhängige Erscheinungen.

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Summary The behaviour of the dorsal muscle of leech in solutions of different osmotic pressure and different ions has been investigated. In pure sugar solutions as well as in pure solutions of sodium chloride the permanent state of length (tonus) of the muscle depends on the osmotic pressure of the solution. The curve representing the relation between pressure and length reveals in both cases a turning point. The muscle beeing in equilibrium in n/10-NaCl solution relaxes with diminishing osmotic pressure untill a concentration of n/20–n/30 is reached. With further diminution starts a contraction.In sodium free sugar solutions the turning point lies at approximatly molar concentrations that is at osmotic pressure ten times higher. Increase of sugar concentration leads to relaxation and its diminution to a contraction.Addition of potassium to the NaCl solution without disturbing the isotonic condition produces also a change of the state of length or the tonus. This change too depends on the concentration and shows a turning point at a K-concentration of about n/250–n/200. Lower concentrations produce a relaxation and higher ones a contraction. Calcium has a relaxing effect in all concentrations. It is an antagonist of potassium as far as the latter one produces a contraction, but acts as its Synergist in K-concentrations leading to a relaxation.In a medium rich in oxygen the electrical excitability of the muscle may be preserved for more than 30 hours. The muscle shows a great power of summation even for single shocks not effective by itself. The velocity of relaxation increases with the steepness of the contraction. Lack of oxygen diminishes the tonus and accelerates the relaxation. Hypotonic solutions increase while hypertonic ones diminish the electrical excitability. Potassium has little influence whereas calcium produces a strong diminution of excitability.Therefore tonus and contractions by stimulation are entirely independent phenomena.

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Karl von Frisch zum 60. Geburtstag gewidmet.     

Polyploids and aneuploids of crepis capillaris produced by treatment with nitrous oxide

Summary When plants ofCrepis capillaris are treated with nitrous oxide of ten atmospheres pressure for four to six hours, at the time when the first or second zygotic divisions are passing in their pollinated flowers, a fair yield of polyploid and aneuploid plants is obtained in their progeny.     

Biotization of Arabidopsis thaliana with Pseudomonas putida and assessment of its positive effect on in vitro growth

Determination of the optimal inoculation method and concentration to use for plant-bacteria interaction studies is important in many cases, such as the phytoremediation of heavy metals and other toxic compounds in contaminated areas. The aim of this study was to compare different concentrations and times of inoculation of Pseudomonas putida with various growth stages of Arabidopsis thaliana in 14-d in vitro cultures. A significant beneficial impact of the bacterium was detected in the shoot length and root weight of seedlings. The highest shoot length and root fresh and dry weights were detected in 14-d and 2 × 10³ cfu mL⁻¹ inoculated samples. In addition, the increase in root weight could be visualized with crystal violet staining, as relatively more root hair and lateral root formation occurred in seedlings inoculated with moderate concentrations of bacteria, possibly due to the ability of P. putida to produce indole-acetic acid. Moreover, the highest photosynthetic pigment accumulation was obtained with the highest bacterial inoculum (2 × 10⁶ cfu mL⁻¹), which was tested in 0- or 3-d-old seedlings. Rhizospheric bacterial colonization was also visualized with GFP-labeled bacteria by confocal microscopy. These results showed that biotization of A. thaliana with P. putida KT2440 did not cause severe oxidative stress in seedlings, because H₂O₂ accumulation levels together with CAT and POX activities were not significantly induced. Therefore, this strain could be used for several applications based on plant-bacteria interactions.

     

Identification of copy number variants in children and adolescents with autism spectrum disorder: a study from Turkey

Molecular Biology Reports - Copy number variants (CNVs) play a key role in the etiology of autism spectrum disorder (ASD). Therefore, recent guidelines recommend chromosomal microarrays (CMAs) as...     

Debio-0932, a second generation oral Hsp90 inhibitor,induces apoptosis in MCF-7 and MDA-MB-231 cell lines

Molecular Biology Reports - Heat shock protein 90 (Hsp90) is a key chaperone that is abnormally expressed in cancer cells, and therefore, designing novel compounds to inhibit chaperone activities...     

Effects of caffeic acid phenethyl ester (CAPE) on angiogenesis,apoptosis and oxidatıve stress ın various cancer cell lines

ABSTRACT

Cancer is a common cause of death worldwide. Approximately 80% of cancer patients use complementary or alternative medicines for treatment. Caffeic acid phenethyl ester (CAPE), the main active component of propolis, exhibits cytotoxic, antiproliferative and anti-cancer effects. Despite its anticancer effects CAPE exhibits no known harmful effects toward normal cells. We investigated the effects of CAPE on angiogenesis, apoptosis and oxidative stress using MDA MB-231, N2a and COLO 320 cell lines and CAPE treatments at 24 and 48 h. A two dimensional cell culture system was used and the findings were evaluated by an indirect immunohistochemical method and H-scores were calculated. CAPE was effective for all three cancer cell lines. After 24 and 48 h, we found a significant decrease in live cells and increased stress in the cells based on e-NOS and i-NOS levels.     

The effects of aflatoxin B1 on growth hormone regulated gene-1 and interaction between DNA and aflatoxin B1 in broiler chickens during hatching

Many types of aflatoxin cause problems for both public and animal health. Aflatoxin B₁ (AFB₁) is the most toxic and commonly encountered fungal toxin that appears in poultry feed and in feeds stored under unsuitable conditions. AFB₁ decreases feed quality, egg production and fertility of hatching eggs. Also, AFB₁ alters the development of embryos by infecting eggs. We investigated using sequence analysis the changes caused by different concentrations of AFB₁ on the promoter sequences of the growth hormone regulated gene-1 (GHRG-1) in chick embryo at 13, 17, 19 and 21 days incubation. DNA isolated from the liver of chick embryos treated with different concentrations of AFB₁ was separated using agarose gel electrophoresis to detect apoptosis, and DNA interaction with AFB₁ was investigated using plasmids to detect changes in electrophoretic mobility and their effects on DNA. Base changes of the promoter sequences of GHRG-1 in 5 ng/egg, 15 ng/egg and 40 ng/egg doses of AFB₁ were increased on day 19 compared to base changes of the same AFB₁ doses on day 13. We also found that AFB at different concentrations changed the mobility of DNA by binding to it, and that high doses of AFB1 destroyed DNA. The DNA interaction study using plasmid demonstrated that AFB₁ at high doses was bound to plasmid DNA, slowed its mobility and inhibited restriction cuts.     

Association between Gene Polymorphism of Manganese Superoxide Dismutase and Prostate Cancer Risk

Manganese superoxide dismutase (MnSOD) is the most effective antioxidant enzyme in mitochondria and protects cells from reactive oxygen species‐induced oxidative damage. The aim of this study was to investigate the association between MnSOD Ala‐9Val gene polymorphism and prostate cancer (PCa) risk in Turkish men with prostate cancer. 33 patients with PCa and 81 control individuals were included in the study. We observed an association between MnSOD Ala/Ala frequency and a higher PCa risk. In addition, we found that the increased risk of early‐onset PCa (under age of 65) in the men homozygous for Ala allele was higher than the men homozygous for Val allele. However, we determined that MnSOD Ala‐9Val genotype was not associated with the aggressiveness of the disease. The results of our study suggest that MnSOD Ala/Ala genotype may influence on early‐onset of PCa patients, but no effect on subsequent development of the disease in Turkish men. However, our study has a limitation that is small numbers of individuals for cases and controls. Therefore, the presented study limited our statistical power to fully investigate the gene polymorphism on cancer risk. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:213‐218, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21472     

Resveratrol treatment protects against doxorubicin-induced cardiotoxicity by alleviating oxidative damage

The possible protective effects of resveratrol (RVT) against cardiotoxicity were investigated in Wistar albino rats treated with saline, saline+doxorubicin (DOX; 20 mg/kg) or RVT (10 mg/kg)+DOX. Blood pressure and heart rate were recorded on the 1^st week and on the 7^th week, while cardiomyopathy was assessed using transthoracic echocardiography before the rats were decapitated. DOX-induced cardiotoxicity resulted in decreased blood pressure and heart rate, but lactate dehydrogenase, creatine phosphokinase, total cholesterol, triglyceride, aspartate aminotransferase and 8-OHdG levels were increased in plasma. Moreover, DOX caused a significant decrease in plasma total antioxidant capacity along with a reduction in cardiac superoxide dismutase, catalase and Na⁺,K⁺-ATPase activities and glutathione contents, while malondialdehyde, myelopreoxidase activity and the generation of reactive oxygen species were increased in the cardiac tissue. On the other hand, RVT markedly ameliorated the severity of cardiac dysfunction, while all oxidant responses were prevented; implicating that RVT may be of therapeutic use in preventing oxidative stress due to DOX toxicity.