The molecular basis of mutations at the Waxy locus from Amaranthus caudatus L.: evolution of the waxy phenotype in three species of grain amaranth

Polymorphisms at the Waxy locus of Amaranthus caudatus L. collected from a wide range of regions were used to investigate genetic diversity and mutation sites. A comparison of the Waxy locus revealed a very high level of sequence conservation. This result clearly showed low environmental and evolutionary variability in the Waxy gene. We also performed screening to confirm the mutation sites in the coding sequences of all accessions. The results indicate that one insertion in the coding region of Waxy genes was responsible for the change in perisperm starch leading to the waxy phenotype in all accessions of this species, and thus that a single mutation event altered the regulation of the Waxy gene during the domestication of this crop. In addition, phylogenetic analysis showed that waxy phenotypes within each of three species, A. caudatus, A. cruentus and A. hypochondriacus, originated separately or differentiated from nonwaxy phenotypes of each species through a single mutational event (i.e., a frame shift or base substitution). We also compared obvious structural features of the coding sequence of waxy and nonwaxy phenotypes with those of low-amylose phenotypes in A. caudatus. The Waxy coding sequences of low-amylose phenotypes do not show polymorphisms and are identical with those of waxy phenotypes. This could mean that there is another gene that encodes a key enzyme responsible for amylose synthesis as the elementary quantity in tissues other than perisperm in A. caudatus.     

Determinants of Slow Walking Speed in Ambulatory Patients Undergoing Maintenance Hemodialysis

Walking ability is significantly lower in hemodialysis patients compared to healthy people. Decreased walking ability characterized by slow walking speed is associated with adverse clinical events, but determinants of decreased walking speed in hemodialysis patients are unknown. The purpose of this study was to identify factors associated with slow walking speed in ambulatory hemodialysis patients. Subjects were 122 outpatients (64 men, 58 women; mean age, 68 years) undergoing hemodialysis. Clinical characteristics including comorbidities, motor function (strength, flexibility, and balance), and maximum walking speed (MWS) were measured and compared across sex-specific tertiles of MWS. Univariate and multivariate logistic regression analyses were performed to examine whether clinical characteristics and motor function could discriminate between the lowest, middle, and highest tertiles of MWS. Significant and common factors that discriminated the lowest and highest tertiles of MWS from other categories were presence of cardiac disease (lowest: odds ratio [OR] = 3.33, 95% confidence interval [CI] = 1.26–8.83, P<0.05; highest: OR = 2.84, 95% CI = 1.18–6.84, P<0.05), leg strength (OR = 0.62, 95% CI = 0.40–0.95, P<0.05; OR = 0.57, 95% CI = 0.39–0.82, P<0.01), and standing balance (OR = 0.76, 95% CI = 0.63–0.92, P<0.01; OR = 0.81, 95% CI = 0.68–0.97, P<0.05). History of fracture (OR = 3.35, 95% CI = 1.08–10.38; P<0.05) was a significant factor only in the lowest tertile. Cardiac disease, history of fracture, decreased leg strength, and poor standing balance were independently associated with slow walking speed in ambulatory hemodialysis patients. These findings provide useful data for planning effective therapeutic regimens to prevent decreases in walking ability in ambulatory hemodialysis patients.     

Analysis of water in Autonomous Biological Systems (ABS) samples.

Several soluble components, peptidase and amino acids, and carbon isotopic ratio in the water retrieved from flight experiments of Autonomous Biological Systems (ABS) as well as ground control samples are analyzed to interpret the condition, dynamics, material balance of the ABS ecosystems. Organic carbons in flight samples were found to be more abundant compared with the control ones, which suggested the uniform ecosystems in low gravity might easily dissolve more soluble components. The Mir-1997 flight sample showed higher C/N ratio probably because of the dissolution of carbon-rich plant materials.     

Chemical, physicochemical and spectrophotometric properties of crystalline chlorophyll-protein complexes from Lepidium virginicum L

Two kinds of water-soluble chlorophyll-protein complexes were prepared from leaves of Lepidium virginicum L., one (CP661) from the plant cultivated in a green house from seeds collected near Mono Lake, CA, and the other (CP-663) from a plant collected at Narashino, Chiba, Japan, by ammonium sulfate fractionation followed by column chromatography on DEAE-cellulose and Sephacryl S-200. The chlorophyll . proteins were further purified by crystallization. CP661 has absorption peaks at 661, 468, 439, 419, 380, 339 and 272 nm. CP663 had absorption peaks at 663, 469, 438, 419, 379, 338 and 272 nm. Estimated molecular weights were 78 000 for CP661 and 80 000 for CP663 by gel filtration chromatography and 83 000 for CP661 and 107 000 for CP663 by an equilibrium sedimentation method. 1 mol chlorophyll . protein contained 4 mol chlorophyll a and b with ratios of 1.0 in CP661 and 1.6 to 1.9 in CP663, but no carotenoids. These characters are different from those of chlorophyll-protein complexes which are prepared from the thylakoid membranes of chloroplasts with detergents.     

Precise identification of gene products in hearts after in vivo gene transfection, using Sendai virus-coated proteoliposomes.

Both efficient gene transfer and the exact identification of gene product are required for gene therapy. Gene transfection of green fluorescence protein (GFP) might be useful for the reporter. After in vivo cotransfection of GFP and beta-galactosidase (beta-Gal) genes in Sendai virus-coated proteoliposomes to rat hearts, we compared the sensitivity and specificity of three methods: GFP detection, histochemical staining (HC) of beta-Gal activity, and immunostaining (IS) of the beta-Gal protein. Fluorescence microscopy and double staining of HC and IS revealed that both GFP and IS were equally sensitive and fourfold superior to HC at the peak of gene expression. However, different from skeletal muscle, the GFP of transfected cardiomyocytes showed two demerits: the fluorescence quenching due to the intense staining of beta-Gal activity, and nonspecific autofluorescence from myocardium. Thus, specific IS would be so far the most reliable to identify the gene product in heart.     

Effects of epinephrine and oxytocin on the release of prostaglandin F from the rat uterus in vitro

Isolated uteri from rats with regular 4-day cycles were incubated in Krebs-Ringer bicarbonate buffer and the release of PGF into the medium was measured by radioimmunoassay after extraction of the incubation medium with ethyl acetate at pH 3.0-3.5. PGF was produced from endogenous precursors and accumulated in equal amounts in the medium during two successive 60 min periods on each day of cycle, but the magnitude of the production varied significantly during the cycle, being greatest in estrus. Oxytocin in doses up to 500 mU/ml had no effect on PGF accumulation in the incubation period at any stage of the cycle, while epinephrine (10(-3)) greatly stimulated PGF release from the estrous uterus but had no effect on PGF release from the diestrous uterus. Phentolamine, an alpha-blocking agent, had no effect on the epinephrine-induced release of PGF, while propranolol, a beta-blocking agent, not only prevented in increase in PGF production induced by epinephrine but also reduced the basal release of PGF by the estrous uterus. Since oxytocin contracts and epinephrine relaxes the nonpregnant rat uterus both in vivo and in vitro, it is unlikely that the effects of these two compounds on uterine contractility are mediated by the release of PGF2alpha.     

Records ofApristurus herklotsi (Lamniformes,Scyliorhinidae) and discussion of its taxonomic relationships

Additional specimens of the rareApristurus herklotsi are reported, and the characteristic features of this species are discussed.A. herklotsi is concluded to be a distinct species, having a very long snout, a narrow distance between the nostrils, a long caudal fin, a short abdomen, numerous teeth on both jaws, and a low number of monospondylous vertebrae.A. herklotsi appears to be mature at about 44 cm in total length.     

Wiring diagrams of MAPK regulation by MEKK1, 2, and 3.

Mitogen-activated protein kinase (MAPK) pathways are activated by a plethora of stimuli. The literature is filled with papers describing the activation of different MAPKs by almost any stimulus or insult imaginable to cells. In this review, we use signal transduction wiring diagrams to illustrate putative upstream regulators for the MAPK kinase kinases, MEKK1, 2, and 3. Targeted gene disruption of MEKK1, 2, or 3 defined phenotypes for each MEKK associated with loss of specific MAPK regulation. Genetic analysis of MEKK function clearly defines specific components of the wiring diagram that require MEKK1, 2, or 3 for physiological responses. We propose that signal transduction network wiring diagrams are valuable tools for hypothesis building and filtering physiologically relevant phenotypic responses from less connected protein relations in the regulation of MAPK pathways.     

Chromosomal mapping of 18S-28S rRNA genes and 10 cDNA clones of human chromosome 1 in the musk shrew (Suncus murinus).

The direct R-banding fluorescence in situ hybridization (FISH) method was used to map 18S-28S ribosomal RNA genes and 10 human cDNA clones on the chromosomes of the musk shrew (Suncus murinus). The chromosomal locations of 18S-28S ribosomal RNA genes were examined in the five laboratory lines and wild animals captured in the Philippines and Vietnam, and the genes were found on chromosomes 5, 6, 9, and 13 with geographic variation. The comparative mapping of 10 cDNA clones of human chromosome 1 demonstrated that human chromosome 1 consisted of at least three segments homologous to Suncus chromosomes (chromosomes 7, 10, and 14). This approach with the direct R-banding FISH method is useful for constructing comparative maps between human and insectivore species and for explicating the process of chromosomal rearrangements during the evolution of mammals.     

Oxygen transfer properties and dimensions of red blood cells in high-altitude camelids,dromedary camel and goat

Summary To estimate the advantage of the small red blood cells (RBC) of high-altitude camelids for O₂ transfer, the kinetics of O₂ uptake into and release from the RBC obtained from llama, vicuña and alpaca were investigated at 37°C with a stopped-flow technique. O₂ transfer conductance of RBC (G) was estimated from the rate of O₂ saturation change and the corresponding O₂ pressure difference between medium and hemoglobin. For comparison, O₂ kinetics for the RBC of a lowaltitude camelid (dromedary camel) and the pygmy goat were determined and previously measured values for human RBC were used. O₂ transfer of RBC was found to be strongly influenced by extracellular diffusion, except with O₂ release into dithionite solutions of sufficiently high concentration (>30 mM). TheG values measured in these standard conditions,G _st (in mmol · min^–1 · Torr^–1 · (ml RBC)^–1) were: high-altitude camelids, 0.58 (averaged for llama, alpaca and vicuña since there were no significant interspecific differences); camel 0.42; goat, 0.42; man, 0.39. The differences can in part be attributed to expected effects of the size and shape of the RBC (volume, surface area, mean thickness), as well as to the intracellular O₂ diffusivity which depends on the concentration of cellular hemoglobin. The highG _st of RBC of highaltitude camelids may be considered to enhance O₂ transfer in lungs and tissues. But the O₂ transfer conductance of blood, , equal toG _st multiplied by hematocrit (in mmol · min^–1 · Torr^–1 · (ml blood)^–1), was only slightly higher as compared to other species: 0.20 (llama, alpaca, vicuña), 0.14 (camel), 0.18 (goat), 0.17 (man).Abbreviations DPG 2,3-diphosphoglycerate - G conductance - Hb hemoglobin - RBC red blood cells - percent saturation of hemoglobin