Testing uniformity of mutants of the <Emphasis Type=Italic>Lathyrus Sativus</Emphasis> L. (grasspea) using Bennet’s method

In this paper interest is focused on uniformity of individual mutants. Because before the registration of a new variety the criteria for DUS (distinctness, uniformity and stability) are checked, so you should also check whether the mutant meets them. The aim of created mutants, in many genetic experiments, is to expand variation of the initial material. This is achieved through use of the mutagen or combination of mutagens on different stages of plants growth. The experimenter should choose some of obtained mutants (for example these which showed better property as regards the same trait). Calculations were done on the basis of results of test with variety Krab of the Lathyrus sativus L. (grasspea) species and 17 mutants getting from this variety. Uniformity was checked with the use of the Bennett’s method which is based on testing of equality of coefficients of variation. After analysis the mutants with codes K3, K37, K63, and K64 were detected as uniform at the same level as variety Krab.     

Diminished mesenteric vaso- and venoconstriction and elevated plasma ANP and BNP with simulated microgravity.

Diminished constriction of arteries and veins following exposure to microgravity or bed rest is associated with a reduced ability to augment peripheral vascular resistance (PVR) and stroke volume during orthostasis. We tested the hypothesis that small mesenteric arteries and veins, which are not exposed to large pressure shifts during simulated microgravity via head-down tail suspension (HDT), will exhibit decrements in adrenergic constriction after HDT in rats. Small mesenteric arteries and veins from control (Con; n = 41) and HDT (n = 35) male Sprague-Dawley rats were studied in vitro. Vasoactive responsiveness to norepinephrine (NE) in arteries (10(-9) to 10(-4) M) and veins (pressure-diameter responses from 2 to 12 cmH(2)O after incubation in 10(-6) or 10(-4) M NE) were evaluated. Plasma concentrations of atrial (ANP) and NH(2)-terminal prohormone brain (NT-proBNP) natriuretic peptides were also measured. In mesenteric arteries, sensitivity and maximal responsiveness to NE were reduced with HDT. In mesenteric veins there was a diminished venoconstriction to NE at any given pressure in HDT. Plasma concentrations of both ANP and NT-proBNP were increased with HDT, and maximal arterial and venous constrictor responses to NE after incubation with 10(-7) M ANP or brain natriuretic peptide (BNP) were diminished. These data demonstrate that, in a vascular bed not subjected to large hydrodynamic differences with HDT, both small arteries and veins have a reduced responsiveness to adrenergic stimulation. Elevated levels of circulating ANP or NT-proBNP could adversely affect the ability of these vascular beds to constrict in vivo and conceivably could alter the intrinsic constrictor properties of these vessels with long-term exposure.     

Inhibition of active lymph pump by simulated microgravity in rats

During spaceflight the normal head-to-foot hydrostatic pressure gradients are eliminated and body fluids shift toward the head, resulting in a diminished fluid volume in the legs and an increased fluid volume in the head, neck, and upper extremities. Lymphatic function is important in the maintenance of normal tissue fluid volume, but it is not clear how microgravity influences lymphatic pumping. We performed a detailed evaluation of the influence of simulated microgravity on lymphatic diameter, wall thickness, elastance, tone, and other measures of phasic contractility in isolated lymphatics. Head-down tail suspension (HDT) rats were used to simulate the effects of microgravity. Animals were exposed to HDT for 2 wk, after which data were collected and compared with the control non-HDT group. Lymphatics from four regional lymphatic beds (thoracic duct, cervical, mesenteric, and femoral lymphatics) were isolated, cannulated, and pressurized. Input and output pressures were adjusted to apply a range of transmural pressures and flows to the lymphatics. Simulated microgravity caused a potent inhibition of pressure/stretch-stimulated pumping in all four groups of lymphatics. The greatest inhibition was found in cervical lymphatics. These findings presumably are correlated to the cephalic fluid shifts that occur in HDT rats as well as those observed during spaceflight. Flow-dependent pump inhibition was increased after HDT, especially in the thoracic duct. Mesenteric lymphatics were less strongly influenced by HDT, which may support the idea that lymph hydrodynamic conditions in the mesenteric lymphatic during HDT are not dramatically altered.