Systematic position of Streptomyces luteofluorescens]

On the basis of the cell wall composition (the presence of meso-diaminopimelic acid and madurose sugar) and according to the morphological structure, Streptomyces luteofluorescens (type culture 719, ISP 5398) is transferred to Actinomadura genus. The organism is considered to be a new species of the Actinomadura genus -- Actinomadura luteofluorescens (Shinobu, 1962) Preobrazhenskaya et Lavrova, 1974, comb. nov.     

Isoosmotic type of regulation in the sturgeon, Acipenser güldenstaedti, in the marine period of its life]

Concentration of osmotically active substances in the blood serum of the sturgeon A. guldenstaedti and sevruga A. stellatus from the central part of the Caspian Sea is practically equal to that in the sea water. In the blood serum of the sturgeon and the sevruga, concentration of Na is higher, whereas concentration of K and Mg is lower than in the sea water. Excretion of the urine with relatively low Mg concentration presumably indicated that being isoosmotic to the medium, the fishes studied in the Caspian Sea do not swallow the sea water. Electronmicroscopic studies indicate that with respect to poor development of membranous structures at the base of cells in the proximal tubuli, the kidney of the sturgeon and sevruga stands closer to freshwater than marine teleosts. These data show specific pattern of the osmotic and ionic regulation in the sturgeon, i.e. its isoosmotic type during migration to the Caspian Sea.     

The temperature hysteresis of water-salt metabolism in the frog Rana temporaria]

Frogs acclimated to 4 degrees C were transported to a medium with temperature 20 degrees C, which caused polyuria; recovery of normal diuresis took about 24 h. During this period, hypernatremia was observed together with the increase in natriuresis, the rate of renal excretion of potassium ions with urea remaining constant. Water content of skeletal muscles decreased. Transportation of frogs acclimated to 20 degrees C into a medium with a temperature 4 degrees C decreased their diuresis. Renal excretion of sodium, calcium and magnesium ions remained unchanged, whereas that of potassium ions significantly decreased. The content of potassium and magnesium in the blood serum increased, that of sodium--decreased. Hydratation of muscled and kidneys was accompanied by the decrease of calcium, potassium and magnesium ions calculated per wet weight of the tissues, the level of sodium remaining unaffected. The data obtained indicate significant changes in the pattern of water and salt metabolism in frogs during temperature hysteresis.     

Peripheral hyaline blebs (podosomes) of macrophages

The plasmalemma and hyaline ectoplasm together constitute the sensory and motor organ of macrophages. The purpose of this study was to isolate this cell fraction in order to analyze it biochemically and functionally. Brief sonification of warmed rabbit lung macrophages caused release of heterodisperse hyaline blebs and filopodia, which were easily collected by differential centrifugation. Viewed in the electron microscope, these structures consisted of membrane-bounded sacs principally containing actin filaments. Some contained secondary lysosomes. They were enriched threefold over whole cell homogenates in specific adenylate cyclase activity and in trichloroacetic-acid-precipitable (125)I when derived from cells labeled with 125(I) by means of a lactoperoxidase-catalyzed reaction. These markers were found to have identical isopycnic densitites when macrophage homogenates were subjected to sedimentation in a focusing sucrose density gradient system, and these markers had densities distinct from those of other cytoplasmic organelles. These markers were therefore assumed to be associated with macrophage plasma membranes. The specific β- glucuronidase activity of the bleb fraction was similar to that of homogenates, but the blebs had considerably lower specific succinic dehydrogenase activity and RNA content, and DNA was undetectable. Electrophoresis of blebs solubilized in sodium dodecyl sulfate on polyacrylamide gels revealed polypeptides co-migrating with macrophage actin-binding protein, myosin, and actin; blebs also had EDTA-activated adenosine triphosphatase activity characteristic of myosin. The concentrations of actin-binding protein and myosin were higher in blebs than in cells or cytoplasmic extracts, whereas actin concentrations were similar (relative to extracts) or only slightly greater (than in cells). Blebs and intact cells had high lactate dehydrogenase activities in the presence but not the absence of Triton X-100. Blebs and cells oxidased 1-[(14)C]glucose, and the rate of glucose oxidation was increased substantially in the presence of latex beads. We conclude that intact sacs of plasmalemma encasing contractile proteins and cytoplasmic enzymes can be isolated from macrophages. They are enriched in myosin and actin-binding protein, indicating that the contractile apparatus is regulated in the cell periphery. These structures have the capacity to respond to environmental signals. We suggest the name "podosomes" for them because of their resemblance to macrophage pseudopodia. We propose that podosome formation results from rapid dissolution of the cortical gel when the membrane is in an actively extended configuration.     

A Novel Fluorescent Analog of the Dopamine Reuptake Inhibitor GBR12909

Russian Journal of Bioorganic Chemistry - Dopamine transporter is a transmembrane protein associated with regulation of dopaminergic signal transmission by dopamine reuptake from the synaptic cleft...     

Neurogenesis in the Hippocampus of Mice Exposed to Short-Term Hindlimb Unloading

Journal of Evolutionary Biochemistry and Physiology - Long-term spaceflights and simulated microgravity negatively affect the number of cognitive functions, including memory, learning, spatial...     

Salivary alpha amylase and salivary cortisol response to fluid consumption in exercising athletes

The objective of the study was to examine salivary biomarker response to fluid consumption in exercising athletes. Exercise induces stress on the body and salivary alpha amylase (sAA) and salivary cortisol are useful biomarkers for activity in the sympathoadrenal medullary system and the hypothalamic pituitary adrenal axis which are involved in the stress response. Fifteen college students were given 150 ml and 500 ml of water on different days and blinded to fluid condition. The exercise protocol was identical for both fluid conditions using absolute exercise intensities ranging from moderate to high. Saliva was collected prior to exercise, post moderate and post high intensities and analyzed by Salimetrics assays. Exercise was significant for sAA with values different between pre-exercise (85 ± 10 U · ml⁻¹) and high intensity (284 ± 30 U · ml⁻¹) as well as between moderate intensity (204 ± 32 U · ml⁻¹) and high intensity. There was no difference in sAA values between fluid conditions at either intensity. Exercise intensity and fluid condition were each significant for cortisol. Cortisol values were different between pre-exercise (0.30 ± 0.03 ug · dL⁻¹) and high intensity (0.45 ± 0.05 ug · dL⁻¹) as well as between moderate intensity (0.33 ± 0.04 ug · dL⁻¹) and high intensity. Moderate exercise intensity cortisol was lower in the 500 ml condition (0.33 ± 0.03 ug · dL⁻¹) compared with the 150 ml condition (0.38 ± 0.03 ug · dL⁻¹). This altered physiological response due to fluid consumption could influence sport performance and should be considered. In addition, future sport and exercise studies should control for fluid consumption.     

Functional features of the nucleolar organizer in developing oocytes of juvenile birds

The genes of rRNA in the nucleolar organizer region (NOR) are inactivated in the oocytes of adult birds despite the functioning of lampbrush chromosomes. The nucleolus is not formed during all stages of the oocyte development. On the other hand, two morphological forms of oocytes differing by the presence of nucleolus in the germinal vesicle are described in the ovaries of juvenile birds. The activation and function of the ribosomal genes in avian oogenesis is still vague. In this work, the NOR activation in chicken (Gallus gallus domesticus) oocytes is confirmed with the help of fluorescence immunohistochemistry (antibodies against nucleophosmin, fibrillarin, and UBF1) and in situ nucleic acid hybridization (FISH with the probe to ITS1 in pre-rRNA). It is demonstrated that the nucleolus in the oocytes at the lampbrush stage in the chicken ovaries is fragmented after complete inactivation of the ribosome genes: the nucleolar fragments contain fibrillarin but do not contain pre-rRNA molecule. The utility of the ovary 3D reconstruction using serial histological sections for quantification of sex cell population heterogeneity in the ovaries of juvenile birds is demonstrated. The obtained results improve the current insight into the functional NOR state in the oocytes of juvenile female birds and contribute to the concept of diversity in the scenarios of gametogenesis.