2-Ketogluconate Reductase Inhibition by Oxalate

The active site of α-glucosidase from Mucor javanicus IFO 4570 was investigated by kinetic studies. Competition between maltose and soluble starch, and linearity of Lineweaver-Burk plots for the mixed substrates were observed. The dependence of the apparent maximum velocities agreed with those predicted for a single active site mechanism. These results suggest that the enzyme hydrolyzes maltose and soluble starch at a single active site.     

ELF MAGNETIC FIELD EFFECTS ON FATTY ACID COMPOSITION OF PHOSPHOLIPID FRACTION AND REPRODUCTION OF RATS' TESTES

In this study, we investigated how rat reproductive cells, testosterone, and the fatty acid composition of the phospholipid fraction of rats' testis cells are affected by extremely low frequency magnetic field (ELFMF). The change in fatty acid composition of the membrane phospholipid fraction can be the mechanism for this effect. We used a total of 26 male Wistar Albino rats, 14 experimental, and 12 controls. The experimental group rats were exposed to a magnetic field (0.8 mT) for 5 weeks, 3 hr per day. The control group rats were kept between inactive coils. After 5 weeks, the testis tissues and sperm cells of all rats were histopathologically investigated and sperm counts determined. Epididymal sperm count did not change compared to the control group (p>.05). Besides this, amorphous head, banana-like head, hammer head, coiled tail, abnormal mid-piece and tail, multiple, and cytoplasmic-droplet type cell numbers did not change in either group (p>.05). However, a statistical difference was found between the control and experimental groups with respect to head with lack of hook and isolated head type sperm (p<.05). In addition, testosterone levels were also found to be altered (p<.05). In the histopathologic investigation of testis tissue, decreased spermatogenesis in some seminiferous tubules, congestion in blood vessels of the interstitium, and increases in interstitial edema and Sertoli cells were observed. Leydig cells were found to be normal in appearance. The fatty acid of the testis cell membrane phospholipids was decreased in the experimental group with respect to the control group.     

Cytokinin-like active principle associated with rice necrosis mosaic virus induced growth promotion in jute (Corchorus olitorius L.)

Rice necrosis mosaic virus-inoculated jute plants looked more juvenile with enhanced leaf size than control ones. Such enlarged leaves and those from control ones were collected separately and extracted in chilled methanol. The crude tissue extract in case of inoculated ones showed three times higher activity in bioassay for cytokinin over control. Biological assay with fractions of crude extract separated by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) was ascertained, and one fraction from inoculated sample showing higher activity in terms of growth over respective control was selected. Ultraviolet/visible absorbance spectra of TLC-separated fractions revealed the presence of different quantities of similar kind of compounds in both control and inoculated samples. A major compound with same m/z value of 217.1 was found in both cases as revealed through electrospray ionisation mass spectrophotometry analysis along with some other minor compounds. Different proton–proton coupling and a molecular structure of the highly substituted aliphatic groups were found in the material from inoculated sample having higher cytokinin-like activity than the control one, which was noticed through ¹H one-dimensional nuclear magnetic resonance analysis.     

Field observations of the effect of Metarhizium anisopliae var. acridum on the saxaul locust,Dericorys albidula Serville (Orthoptera: Dericorythidae)

Dericorys albidula Serville (Orthoptera: Dericorythidae) is a major pest of Haloxylon ammodendron and other saxaul plant species in the Qom province, Iran. Using fungal insecticides can be an alternative method for chemical insecticides. Effect of insecticide fungi, Metarhizium anisopliae var. acridum, on the various nymphs of D. albidula was studied in the field through 2005 and 2006. Fixed concentrations of fungi (10⁶, 10⁷, 10⁸, 10⁹, 10¹⁰ and 10¹³ spore mL^?1) were prepared as gasoline formulation and were sprayed on the locusts on H. ammodendron trees, and mortality percentage was recorded 15 days after treatment. The results showed that various concentrations significantly affected on the second, third, fourth and fifth nymphal instars of D. albidula compared to control in 2006, although this effect was lower in 2005 on nymphs. Mortality of the highest concentration (10¹³ spore mL^?1) was higher (17.6–24%) than other concentrations in all tests, but these values were not notable. The results of this study showed that using M. anisopliae var. acridum diluted in gasoline can be effective on nymphal instars of locust, D. albidula, in two continuous years.     

Planarian activity differences when maintained in water pre-treated with magnetic fields: a nonlinear effect

There have been multiple claims that exposing water to a static magnetic field affects its properties which influence living systems. To test this hypothesis, planarian subsequent to dissection were maintained in spring water that had been previously exposed for only one day to one of three (16, 160, or 1,600 G) intensity static magnetic fields or to a reference condition. Although there was no significant difference in regeneration rates over the subsequent seven-day period, there was a statistically significant nonlinear effect for planarian mobility and diffusion rates. Both mobility rates and diffusion velocity of a liquid within the water that had been exposed to the 16 G field was about twice that for water exposed to the other intensities. These results imply that nonlinear biophysical effects may emerge under specific conditions of intensity ranges for particular volumes of water.     

Attachment styles impact on pet visitation effectiveness

Abstract

This paper describes a field study on the effects of attachment styles on the subjective well-being of institutionalized older persons after participating in a pet visitation program. We compared how attachment style (i.e., secure, anxious ambivalent, dismissive avoidant, and fearful avoidant) moderated the impact of a dog visitation program in 52 elderly residents of an assisted-living facility. Controlling for pre-visitation mood, the results revealed that the secure style related to increases in positive mood after interacting with the dogs. The anxious ambivalent style related to increases in positive mood and decreases in ratings of depression. Most importantly, the fearful avoidant style related to increases in depression after interacting with the dogs. The results highlight the notion that not all participants benefit from taking part in pet visitation programs. Theoretically, this study presents preliminary evidence for the relevance of attachment styles in understanding human–pet interactions.     

MEMBRANE POTENTIAL AND ENDOGENOUS ION CURRENT OF PHYCOMYCES SPORANGIOPHORES

Glass microelectrodes were inserted into the growing zone of sporangiophores of Phycomyces blakesleeanus that had been submersed in artificial pond water. The membrane potential (inside negative) increased with increasing pH of the bathing solution from an average of ?98 mV at pH 5 up to ?131 mV at pH 7. Removal of Ca²⁺ from the medium hyperpolarized the membrane potential in the wild type, but caused a significant depolarization in the blue-light-insensitive madC mutant. KCN, diethylstilbestrol, and N,N′-dicyclohexylcarbodiimide depolarized the membrane potential in both the wild type and the madC mutant, while fusicoccin had no effect. Endogenous ion current of up to 2 μA cm^?2 was measured in the growing zone of sporangiophores with an extracellular vibrating electrode. The current density and current pattern varied with the pH of the medium. At pH 5 most sporangiophores had weak inward current along the growing zone, whereas at pH 7 most sporangiophores had strong outward current. The response of the membrane potential to specific inhibitors and the presence of an endogenous ion current indicate an electrogenic H⁺-ATPase in the plasma membrane. The results show a negative correlation between growth rate of sporangiophores growing in buffered aqueous medium and magnitude of membrane potential, as well as density of outward current. They also indicate an important role of protons in controlling the growth of Phycomyces sporangiophores.     

Analysis of DNA fragmentation in mouse embryos exposed to an extremely low-frequency electromagnetic field

Effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on DNA damage in biological systems are still a matter of dispute. The aim of the present study was to investigate the possible effect of electromagnetic field exposure on DNA fragmentation in cells (blastomers) of mouse blastocysts.

Eighty female NMRI mice were randomly divided into 2 groups of 40 animals each. The control group was left unexposed whereas the animals in the EMF-group were exposed to a 50-Hz EMF at 0.5 mT 4 h per day, 6 days a week for a duration of 2 weeks. After the 8^th day of exposure, the female mice in both groups were superovulated (with injections of pregnant mare serum gonadotropin and human chorionic gonadotropin) and then mated overnight. At approximately 4 days after mating (102 h after the human chorionic gonadotropin treatment), blastocysts were obtained by flushing the uterus horns. The mean numbers of pregnant mice, blastocysts after flushing, blastomers within the blastocysts, and the DNA fragmentation index following staining in both groups were compared using statistical methods (SPSS, the Chi-square test, the Student's t-test and the Mann-Whitney U-test, P < 0.05). The results showed that the mean number of blastocysts after flushing was significantly decreased in the EMF-group compared to that of the control group (P < 0.03). The DNA fragmentation index was significantly increased in the EMF-group compared to control (10.53% vs. 7.14%; P < 0.001). However, there was no significant difference in the mean numbers of blastomers and numbers of pregnant mice between the EMF-exposed and control group. Our findings indicate that the EMF exposure in preimplantation stage could have detrimental effects on female mouse fertility and embryo development by decreasing the number of blastocysts and increasing the blastocysts DNA fragmentation.     

Selective destabilization of tumor cells with pulsed electric and magnetic sequences: a preliminary report

Background: Various studies in vitro suggest that low electric and magnetic fields may modify cancer cell growth and recent studies in vivo have revealed anti-tumoral effects. After screening different tumor cell lines, we identified specific sequences of localized magnetic and electric fields (MESQ) that reduce cancer cell survival in vitro. This finding led us to design an experiment to determine the actual efficacy of above sequences in selectively destabilizing tumor cells and their effect on healthy cells.

Materials and Methods: We exposed the MCF7 cancer cell line and normal fibroblasts to MESQ for 1, 2, 3 and 6 hours, evaluating cell survival and induction of apoptosis.

Results: Exposure to MESQ reduced MCF7 survival, inducing apoptosis in a timedependent way, whereas fibroblasts were completely unaffected.

Conclusion: These results have promising implications for the treatment of cancer and warrant further research.     

Determination of field output correction factors of radiophotoluminescence glass dosimeter and CC01 ionization chamber and validation against IAEA-AAPM TRS-483 code of practice

PurposeTo determine the field output correction factors of the radiophotoluminescence glass dosimeter (RPLGD) in parallel and perpendicular orientations with reference to CC01, the ionization chamber.MethodsThe dose to a small water volume and the sensitive volume of the RPLGD and the IBA-CC01 were determined for 6-MV, 100-cm SAD, 10-cm depth using egs_chamber user-code. The RPLGD in perpendicular and parallel orientations to the beam axis were studied. The field output correction factors of each detector for 0.5 × 0.5 to 10 × 10 cm² field sizes were determined. These field output correction factors were validated by comparing field output factors against data determined from IAEA-AAPM TRS-483 code of practice.ResultsThe field output correction factors of all detectors were within 5% for field sizes down to 0.8 × 0.8 cm². For 0.5 × 0.5 cm², the field output correction factors of CC01, RPLGD in perpendicular and parallel orientations differed from unity by 14%, 19%, and 5%, respectively. The percentage difference between field output factors determined using RPLGD and CC01 data, corrected using the field output correction factors determined in this work and measurements with CC01 data corrected using TRS-483, was less than 3% for all field sizes, except for the smallest field size of RPLGD in perpendicular orientation and the CC01.ConclusionsThe field output correction factors of RPLGD and CC01 are reported. The validation proves that RPLGD in parallel orientation combined with the field output correction factors is the most suitable for determining the field output factors for the smallest field used in this study.