Interactions of Divalent Cations in Their Action on ATPases from Cucumber Roots

A microsomal fraction (10,000–30.000 g) was prepared from roots of Cucumis satirus L. (cv. Bestseller Fl) grown in solution culture. The ATPase activity was stimulated by Mg and Mn with optima between pH 6 and 7. Stimulation by Ca was obtained only above pH 7. Activations by Mg and Mn were inhibited by Ca, Mn and Mg interacted, so that Mn appeared strongly inhibitory for activation by Mg and Mg weakly inhibitory for activation by Mn: the simplest interpretation for this would be two separate enzymes. Cucumber accumulates and deposits Ca contrary to wheat and oat, which contain Ca-activated ATPase in the pH region 6 to 7. The Ca data for cucumber are compared with earlier findings from wheat and oat and are tentatively related to known physiological differences.     

Physiological effects of the lunar cycle on the spawning of a coral reef fish,Abudefduf Vaigiensis: in vivo and in vitro trait

The aim of the present study was to investigate the lunar cycle effects of the spawning of Audefduf vaigiensis through in vivo and in vitro analysis. For this purpose, the indices of GSI, serum levels of sex steroids, including testosterone (T), 17α-hydroxyprogesterone (OHP), 17α, 20β-dihydroxyprogesterone (DHP), and 11-keto-testosterone (11-KT) as well as the germinal vesicle breakdown (GVBD) were measured. The sampling pattern was weekly, based on the moon cycles as the new moon (NM), the first quarter (FQ), the full moon (FM), and the last quarter (LQ). In females, the highest in vivo values of the GSI index were obtained in FQ and LQ, and in males, this value was significantly higher in LQ than NM. The highest in vivo level of OHP in females was observed in FQ, whereas in males was obtained in FM. In both sexes, the in vivo serum levels of DHP were obtained in LQ. In males, the level of 11-KT were at the peak in NM. In vitro analysis showed the highest rate of GVBD in LQ. Moreover, the in vitro levels of T, OHP, and DHP were significantly higher in LQ compare to NM in both sexes. However, in males, the in vitro levels of 11-KT was significantly higher in NM than LQ. These cyclical changes obtained from in vivo plasma steroid hormones and in vitro data on GVBD suggested that lunar periodicity is a major external regulator that synchronized ovarian and testicular activity of A. vaigiensis with emphasis on spawning phenomenon.

     

Leucanthemum Vulgare Lam. Germination,Growth and Mycorrhizal Symbiosis Under Crude Oil Contamination

Oil contamination of soil limits plants’ access to water and nutrients. Leucanthemum vulgare colonized by mycorrhizae could provide an effective tool in remedying oil contamination. Seeds of L. vulgare were planted in pots containing soil mixed with petroleum at 0, 2.5, 5, 7.5, and 10% w/w and propagules of mycorrhizal fungi. Plants were grown under ambient conditions for 16 weeks. Seed germination data were collected weekly for three weeks. Mycorrhizal percentage, spore counts, length and weight of roots and shoots were determined after harvesting. Results showed significant differences in seed germination rates between oil-treated, mycorrhizal and non-mycorrhizal plants. The overall germination rate was greater at 7.5% w/w crude oil contamination (ρ = 0.05) in mycorrhizal and non-mycorrhizal pots with significant differences between their respective Root:Shoot ratios (both length and weight). Results of this research showed L. vulgare could be germinated and grown in crude oil contaminated soils and could be used to augment plant establishment as part of phytoremediation practices.     

The impact of a 6-year comprehensive community trial on the awareness, treatment and control rates of hypertension in Iran: experiences from the Isfahan healthy heart program

Background

Acute mental stress may contribute to the cardiovascular disease progression via autonomic nervous system controlled negative effects on the endothelium. The joint effects of stress-induced sympathetic or parasympathetic activity and endothelial function on atherosclerosis development have not been investigated. The present study aims to examine the interactive effect of acute mental stress-induced cardiac reactivity/recovery and endothelial function on the prevalence of carotid atherosclerosis.

Methods

Participants were 81 healthy young adults aged 24-39 years. Preclinical atherosclerosis was assessed by carotid intima-media thickness (IMT) and endothelial function was measured as flow-mediated dilatation (FMD) using ultrasound techniques. We also measured heart rate, respiratory sinus arrhythmia (RSA), and pre-ejection period (PEP) in response to the mental arithmetic and speech tasks.

Results

We found a significant interaction of FMD and cardiac RSA recovery for IMT (p = 0.037), and a significant interaction of FMD and PEP recovery for IMT (p = 0.006). Among participants with low FMD, slower PEP recovery was related to higher IMT. Among individuals with high FMD, slow RSA recovery predicted higher IMT. No significant interactions of FMD and cardiac reactivity for IMT were found.

Conclusions

Cardiac recovery plays a role in atherosclerosis development in persons with high and low FMD. The role of sympathetically mediated cardiac activity seems to be more important in those with impaired FMD, and parasympathetically mediated in those with relatively high FMD. The development of endothelial dysfunction may be one possible mechanism linking slow cardiac recovery and atherosclerosis via autonomic nervous system mediated effect.     

Brittle stars (Echinodermata: Ophiuroidea) from La Réunion and the systematic position of Ophiocanops Koehler, 1922

The ophiuroid fauna of La Réunion, Indian Ocean, is still incompletely known. We report 13 different species from coral reefs, including five new records and a probably undescribed species of Amphioplus , which increases the number of ophiuroids known from La Réunion to 25. The most important find consists of three individuals of a previously unknown representative of the genus Ophiocanops . Originally placed in Ophiomyxidae, its systematic position has long been debated, with some authors advocating a placement with the otherwise extinct Palaeozoic Oegophiurida, based on the absence of several skeletal characters. The new species, O. multispina sp. nov. , shows intermediate characters between its previously only known congener, O. fugiens , and the ophiomyxid Renetheo felli . The three species appear to represent a line of taxa with progressively reduced skeleton instead of an ancient condition. We propose to transfer Ophiocanops back to the Ophiomyxidae, to synonymize Renetheo with Ophiocanops , and to invalidate the Ophiocanopidae, for which there is no autapomorphy-based support. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 153 , 545–560.     

Immunity to Babesia bigemina in Experimentally Infected Cattle

Two groups of 5 and 6 Babesia bigemina“vaccine donor” animals of which 8 had been splenectomized were challenged 6 and 12 months respectively after they had lost their carrier state. All animals of the former, and 3 of the latter group survived; the remaining 3 animals succumbed to the challenge and died. It was concluded that premunity to B. bigemina is followed by sterile immunity which lasts for at least 6 months. Thereafter it fades gradually with time, depending on the immune response of the host, but can last for at least 12 months. Six splenectomized animals, which had lost their infectivity after treatment of their initial B. bigemina parasitemia at the rapidly rising phase with 1 mg/kg Berenil, died on challenge. It was concluded that a minimum period of contact between host and parasite is required for the acquisition of immunity to B. bigemina. Capillary tube agglutination titers were generally higher in the protected than in the unprotected animals. They remained fairly high for a long period after animals had lost their carrier state, which indicated the sensitivity of the CA test but rendered it unreliable for the detection of carrier animals.     

Research in general practice: a survey of incentives and disincentives for research participation

Background Recruitment rates of general practitioners (GPs) to do research vary widely. This may be related to the ability of a study to incorporate incentives for GPs and minimise barriers to participation.Method A convenience sample of 30 GPs, ten each from the Sydney intervention and control groups Ageing in General Practice ‘Detection and Management of Dementia’ project (GP project) and 10 GPs who had refused participation, were recruited to determine incentives and barriers to participating in research. GPs completed the 11-item ‘Meeting the challenges of research in general practice: general practitioner questionnaire’ (GP survey) between months 15 and 24 of the GP project, and received brief qualitative interviews from a research GP to clarify responses where possible.Results The most important incentives the 30 GPs gave for participating in the project were a desire to update knowledge (endorsed by 70%), to help patients (70%), and altruism (60%). Lack of time (43%) was the main barrier. GPs also commented on excessive paperwork and an inadequate explanation of research.Conclusions While a desire to update knowledge and help patients as well as altruism were incentives, time burden was the primary barrier and was likely related to extensive paperwork. Future recruitment may be improved by minimising time burden, making studies simpler with online data entry, offering remuneration and using a GP recruiter.