Characterization of two D-beta-hydroxybutyrate dehydrogenase populations in heavy and light mitochondria from jerboa (Jaculus orientalis) liver

Mitochondrial membrane-bound and phospholipid-dependent D-beta-hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30), a ketone body converting enzyme in mitochondria, has been studied in two populations of mitochondria (heavy and light) of jerboa (Jaculus orientalis) liver. The results reveal significant differences between the BDH of the two mitochondrial populations in terms of protein expression, kinetic parameters and physico-chemical properties. These results suggest that the beta-hydroxybutyrate dehydrogenases from heavy and light mitochondria are isoform variants. These differences in BDH distribution could be the consequence of cell changes in the lipid composition of the inner mitochondrial membrane of heavy and light mitochondria. These changes could modify both BDH insertion and BDH lipid-dependent catalytic properties.     

Simulation of the cardiovascular system using equivalent electronic system

This paper describes simulation of the cardiovascular system using a complex electronic circuit. In this study we have taken a slightly different approach to the modeling of the system and tried to advance existing electrical models by increasing more segments and parameters. The model consists of 42 segments representing the arterial system. Anatomical and physiological data for circuit parameters have been extracted from medical articles and textbooks. The frequency of heart is 1 Hz and the system operates in steady state condition. Each artery is modeled by one capacitor, resistor and inductor. The left and right ventricles are modeled using AC power suppliers and diodes. The results of the simulation including pressure and volume graphs exhibit operation of the cardiovascular system under normal condition. The results of the simulation have been compared with the relevant experimental observation and are in good agreement with them.     

Conformational study of human serum albumin in pre-denaturation temperatures by differential scanning calorimetry, circular dichroism and UV spectroscopy

Thermal conformational changes of human serum albumin (HSA) in phosphate buffer, 10 mM at pH = 7 are investigated using differential scanning calorimetric (DSC), circular dichroism (CD) and UV spectroscopic methods. The results indicate that temperature increment from 25 degrees C to 55 degrees C induces reversible conformational changes in the structure of HSA. Conformational change of HSA are shown to be a three-step process. Interestingly, melting temperature of the last domain is equal to the maximum value of fever in pathological conditions, i.e. 42 degrees C. These conformational alterations are accompanied by a mild alteration of secondary structures. Study of HSA-SDS (sodium dodecyl sulphate) interaction at 45 degrees C and 35 degrees C reveals that SDS affects the HSA structure at least in three steps: the first two steps result in more stabilization and compactness of HSA structure, while the last one induces the unfolding of HSA. Since HSA has a more affinity for SDS at 45 degrees C compared to 35 degrees C, It is suggested that the net negative charge of HSA is decreased in fever, which results in the decrease of HSA-associated cations and plasma osmolarity, and consequently, heat removal via the increase in urine volume.     

Perforin mediated apoptosis of cerebral microvascular endothelial cells during experimental cerebral malaria

Cerebral malaria is a serious complication of Plasmodium falciparum infection. We have investigated the role of perforin in the pathogenesis of cerebral malaria in a murine model (Plasmodium berghei ANKA (PbA) infection). C57BL/6 mice demonstrated the typical neuropathological symptoms of experimental cerebral malaria infection from day 5p.i. and became moribund on day 6p.i. This pathology was not seen in PbA-infected, perforin-deficient (pfp-/-) mice. From days 5-6p.i. onwards there was a significant increase in mRNA for granzyme B and CD8, but not CD4, in brain tissue from PbA-infected C57BL/6 and pfp-/- mouse brains. Perforin mRNA was strongly increased in the brains of PbA-infected C57BL/6 mice on day 6p.i. Immunohistochemistry revealed increased perforin staining and elevated numbers of CD8(+) cells within the cerebral microvessels in PbA-infected C57BL/6 at days 5 and 6p.i. compared with uninfected animals. At day 6p.i., there were TUNEL-positive cells and activated caspase-3 positive cells of endothelial morphology in the CNS of PbA-infected C57BL/6 mice. The TUNEL-positive cells were greatly reduced in pfp-/- mice. These results suggest that CD8(+)T lymphocytes induce apoptosis of endothelial cells via a perforin-dependent process, contributing to the fatal pathogenic process in murine cerebral malaria.     

Seasonal variation of the ovarian follicular dynamics and luteal functions of sheep in the subtropics

This study was undertaken to describe the development of individual follicles and corpora lutea (CL) in Ossimi ewe lambs at different seasons of the year in the subtropics. Seven ewe lambs underwent daily ultrasonographic examination for 20 interovulatory periods (IOP) during spring, winter and autumn. Ovarian follicles >or=2 mm and corpora lutea were counted and measured. Blood samples were taken for progesterone (P(4)) analysis. All ewe lambs included, but one, were cyclic in all seasons studied. Three (65%) and two (35%) follicular waves were detected per estrous cycle. None of the characteristics of the large follicles was affected by season. Follicles >or=2 mm in diameter were significantly higher in winter. The CL developed slowly in autumn. Serum P(4) level was higher in autumn. Double ovulation was observed only in autumn. The data demonstrated that Ossimi sheep in the subtropics were cyclic in most seasons of the year. Season affected mainly the luteal functions with little influences on the follicular characteristics.     

Effects of insect growth regulators on the hairy rose beetle, Tropinota squalida (Col., Scarabeidae)

Abstract:  Saponin extract from alfalfa roots, azadirachtin from the neem seed oil, synthetic ecdysteroid agonist RH-2485, and the juvenoid hydroprene disturb the development and reproduction of Tropinota squalida . Feeding beetles on diets containing 750 p.p.m. saponins, 7.5 p.p.m. RH-2485, and 1.13 p.p.m. azadirachtin reduces their progeny from 51 second instar larvae per female to 24, 15, and 15 larvae, respectively. When the larvae of untreated adults are fed for 1 week on dung with 75 p.p.m. saponins, 50 p.p.m. RH-2485, and 0.45 p.p.m. azadirachtin, the rate of adult emergence drops from 80% (controls) to 20, 0 and 13%, respectively. No adults emerge when the treatment is continued through the second and third larval instars. Two topical treatments of larvae with 0.2  μ g hydroprene decrease the rate of adult emergence from 90 to 11%, and treatments with 2  μ g prevent adult development in all insects. The observed effects warrant testing of azadirachtin, RH-2485, and hydroprene in the field. Several types of their application for the control of T. squalida are suggested.     

Growth and fragmentation of silver nanoparticles in their synthesis with a fs laser and CW light by photo-sensitization with benzophenone.

The photo-sensitization synthetic technique of making silver nanoparticles using benzophenone is studied using both a laser and a mercury lamp as light sources. The power and irradiation time dependence of the synthesized nanoparticle absorption spectra and their size distribution [as determined by transmission electron microscopy (TEM)] are studied in each method and compared. In the laser synthesis, as either the laser power or the irradiation time increases, the intensity of the surface plasmon resonance absorption at 400 nm is found to increase linearly first, followed by a reduction of the red edge of the plasmon resonance absorption band. The TEM results showed that in the laser synthesis low powers and short irradiation times produce nanoparticles around 20 nm in diameter. Increasing the power or irradiation time produces a second population of nanoparticles with average size of 5 nm in diameter. These small particles are believed to be formed from the surface ablation of the large particles. The surface plasmon absorption band is found to be narrower when the nanoparticles are produced with laser irradiation. Throughout the exposure time with the CW lamp, the plasmon resonance absorption band of the particles formed first grows in intensity, then blue shifts and narrows, and finally red shifts while decreasing in intensity. The TEM results for lamp samples showed particle formation and growth, followed by small nanoparticle formation. The above results are discussed in terms of a mechanism in which, the excited benzophenone forms the ketal radical, which reduces Ag+ in solution and on the Ag nanoparticle surface. As the time of irradiation or the light energy increases the benzophenone is consumed, which is found to be the limiting reagent. This stops the formation of the normal large nanoparticles while their photo-ablation continues to make the small particles.     

Evidence for Aceticlastic Methanogenesis in the Presence of Sulfate in a Gas Condensate-Contaminated Aquifer

The anaerobic metabolism of acetate was studied in sediments and groundwater from a gas condensate-contaminated aquifer in an aquifer where geochemical evidence implicated sulfate reduction and methanogenesis as the predominant terminal electron-accepting processes. Most-probable-number tubes containing acetate and microcosms containing either [2-¹⁴C]acetate or [U-¹⁴C]acetate produced higher quantities of CH₄ compared to CO₂ in the presence or absence of sulfate.¹⁴CH₄ accounted for 70 to 100% of the total labeled gas in the [¹⁴C]acetate microcosms regardless of whether sulfate was present or not. Denaturing gradient gel electrophoresis of the acetate enrichments both with and without sulfate using Archaea-specific primers showed identical predominant bands that had 99% sequence similarity to members of Methanosaetaceae. Clone libraries containing archaeal 16S rRNA gene sequences amplified from sediment from the contaminated portion of the aquifer showed that 180 of the 190 clones sequenced belonged to the Methanosaetaceae. The production of methane and the high frequency of sequences from the Methanosaetaceae in acetate enrichments with and without sulfate indicate that aceticlastic methanogenesis was the predominant fate of acetate at this site even though sulfate-reducing bacteria would be expected to consume acetate in the presence of sulfate.     

Study on genetic coadaptability of wild quail populations in China

Genetic coadaptability, developed from the process of evolution, is one of the properties of gene pool as well as gene frequency of each locus. It was explained in detail by Nei[1] in 1973. He proposed that during evolutionary process, non-allelic genes o…     

Iodo bridged lead(II) compounds of azoimidazoles: Single crystal X-ray structures of [di-iodo-{1-methyl-2-(p-tolylazo)imidazole}lead(II)]n and {1-methyl-3-benzyl-2-(p-tolylazo)imidazolium}m-{tri-iodoplumbate(II)}m

PbI₂ forms iodo-bridged neutral polymer upon reaction with 1-alkyl-2-(arylazo)imidazoles (RaaiR′). The reaction of PbI₂ and dialkyl imidazolium iodides [RaaiR′R″]⁺I⁻ has synthesized {1,3-dialkyl-2-(arylazo)imidazolium}_m-{tri-iodoplumbate(II)}_m. The complexes are characterized by different spectroscopic studies. Iodobridged chelated polymer, [Pb(RaaiR′)I₂]_n, has been established by single crystal X-ray diffraction measurements in one case. Tri-iodoplumbates form iodo bridged anion polymer, which connects [RaaiR′R″]⁺ by hydrogen bonding and are placed in between the pillars of [Pb(μ-I)₆]_n motif.