Three-millimeter-long shoot tips of strawberry 'Senga Sengana' and raspberry 'Norna' encapsulated in calcium alginate were stored in vitro at 4 °C in the dark. The cultures which were donors for the shoot tips were grown before encapsulation on shoot multiplication media (Boxus medium with 2.2 µM BAP and 2.46 µM IBA for strawberry, and MS medium with NH4NO3 and KNO3 reduced by 50%, and with 3.55 µM BAP and 0.49 µM IBA for raspberry) as well as on these media supplemented with 10 g l–1 mannitol or paclobutrazol (1.7 µM for strawberry and 3.4 µM for raspberry). Sodium alginate was dissolved in water, water with sugar or in a culture medium without growth regulators. Regrowth ability of the stored explants and in vitro multiplication in three successive subcultures were evaluated. The encapsulated shoot tips could be stored for 9 months in beads containing sugar or a culture medium. The pre-conditioning of the donor cultures on a mannitol containing medium was beneficial for regrowth ability. The multiplication rate of strawberry and raspberry shoots in the first subculture after storage was lower than that of non-stored cultures. Particularly low multiplication was obtained for strawberry which had been stored for 9 months and for raspberry stored for 3 and 6 months, in combinations where the beads were prepared by dissolving sodium alginate in water. Multiplication of strawberry in the second subculture was generally higher than in non-stored cultures, but multiplication of raspberry was lower also in the second subculture, with the exception of the combination stored for 9 months and pre-cultured on mannitol. In the third subculture, shoot multiplication in both species was similar to that in non-stored cultures. 相似文献
Rhodobacter capsulatus strain BK5 possesses a membrane bound respiratory nitrate reductase rather than the periplasmic enzyme found in other strains. The enzyme in strain BK5 is shown to be both functionally and structurally related to the nitrate reductase of Paracoccus denitrificans and Escherichia coli.Abbreviation TMAO
trimethylamine-N-oxide 相似文献
The distribution of predators is widely recognized to be intimately linked to the distribution of their prey. Foraging theory
suggests that predators will modify their behaviors, including movements, to optimize net energy intake when faced with variation
in prey attributes or abundance. While many studies have documented changes in movement patterns of animals in response to
temporal changes in food, very few have contrasted movements of a single predator species naturally occurring in dramatically
different prey landscapes. We documented variation in the winter movements, foraging range size, site fidelity, and distribution
patterns of a molluscivorous sea duck, the surf scoter (Melanitta perspicillata), in two areas of coastal British Columbia with very different shellfish prey features. Baynes Sound has extensive tidal
flats with abundant clams, which are high-quality and temporally stable prey for scoters. Malaspina Inlet is a rocky fjord-like
inlet where scoters consume mussels that are superabundant and easily accessible in some patches but are heavily depleted
over the course of winter. We used radio telemetry to track surf scoter movements in both areas and found that in the clam
habitats of Baynes Sound, surf scoters exhibited limited movement, small winter ranges, strong foraging site fidelity, and
very consistent distribution patterns. By contrast, in mussel habitats in the Malaspina Inlet, surf scoters displayed more
movement, larger ranges, little fidelity to specific foraging sites, and more variable distribution patterns. We conclude
that features associated with the different prey types, particularly the higher depletion rates of mussels, strongly influenced
seasonal space use patterns. These findings are consistent with foraging theory and confirm that predator behavior, specifically
movements, is environmentally mediated. 相似文献
Governmental and research agencies worldwide have strongly advocated sun avoidance strategies in an attempt to counter marked increases in skin cancer incidence. Concurrently, there are reports describing widespread Vitamin D3 deficiency. Because 1,25-dihydroxyvitamin D3, through interaction with the Vitamin D receptor, exerts pleiotrophic effects, such deficiency might be expected to have clinical consequences. Indeed, various reports indicate that exposure to ultraviolet radiation (UVR) exerts a protective effect on development of some common diseases including internal cancers and multiple sclerosis. We describe studies indicating that modest exposure reduces risk of prostate cancer. The effect of UVR is mediated by skin type; at lower levels of exposure a relative inability to effect skin pigmentation is protective presumably because it allows more efficient Vitamin D3 synthesis. Polymorphic variants in genes associated with pigmentation including melanocyte stimulating hormone receptor and tyrosinase are also associated with prostate cancer risk. Overall, though preliminary and requiring cautious interpretation, these data indicate that moderate UVR exposure together with characteristics linked with less effective tanning confer reduced prostate cancer risk. Clearly, it is important to define safe levels of UVR that do not result in increased risk of skin cancers such as malignant melanoma. 相似文献
The purpose of these investigations was to evaluate the influence of limited nutrient availability in the culture medium on
Proteus vulgaris biofilm formation on surfaces of stainless steel. The relationship between the P. vulgaris adhesion to the abiotic surfaces, the cellular ATP levels, cell surface hydrophobicity and changes in the profiles of extracellular
proteins and lipopolysaccharides was examined. In all experimental variants the starvation conditions induced the bacterial
cells to adhere to the surfaces of stainless steel. Higher ATP content and lower cell surface hydrophobicity of P. vulgaris cells was observed upon nutrient-limited conditions. Under starvation conditions a reduction in the levels of extracellular
low molecular weight proteins was noticed. High molecular weight proteins formed the conditioning layer on stainless steel
plates, making the bacteria adhesion process more favorable. The production of low molecular weight carbohydrates promoted
more advanced stages of P. vulgaris biofilm formation process on the surfaces of stainless steel upon starvation. 相似文献
A profile of free fatty acid (FFA) specificity in Acanthamoeba castellanii mitochondrial uncoupling is described. The FFA uncoupling specificity was observed as different abilities to stimulate resting
respiration, to decrease resting membrane potential, and to decrease oxidative phosphorylation efficiency. Tested unsaturated
FFA (C18–20) were more effective as uncouplers and protonophores when compared to tested saturated FFA (C8–18), with palmitic
acid (C16:0) as the most active. As FFA efficiency in mitochondrial uncoupling is related to physiological changes of fatty
acid composition (and thereby FFA availability) during growth of amoeba cells, it could be a way to regulate the activity
of an uncoupling protein and thereby the efficiency of oxidative phosphorylation during a cell life of this unicellular organism.
Aleksandra Swida and Małgorzata Czarna contributed equally to this work. 相似文献
A simple and efficient method is described for isolating high quality RNA from bilberry fruit. The procedure is based on the
use of hexadecyltrimethyl ammonium bromide (CTAB), polyvinylpyrrolidone (PVP), and β-mercaptoethanol in an extraction buffer
in order to eliminate the polysaccharides and prevent the oxidation of phenolic compounds. This method is a modification of
the one described for pine trees, and yields high-quality RNA suitable for cDNA based methodologies. This method is applicable
for a variety of plant tissues. 相似文献
(1) The ATPase inhibitor protein has been isolated from rat liver mitochondria in purified form. The molecular weight determined by sodium dodecyl sulfate gel electrophoresis is approximately 9500, and the isoelectric point is 8.9.
(2) The protein inhibits both the soluble ATPase and the particle-bound ATPase from rat liver mitochondria. It also inhibits ATPase activities of soluble F1, and inhibitor-depleted submitochondrial particles derived from bovine heart mitochondria.
(3) On particle-bound ATPase the inhibitor has its maximal effect if incubated in the presence of Mg2+. ATP at slightly acidic pH.
(4) The inhibitor has a minimal effect on Pi-ATP exchange activity in sonicated submitochondrial particles. However, unexpectedly the inhibitor greatly stimulates Pi-ATP exchange activity in whole mitochondria while the low ATPase activity of the mitochondria is not affected. The possible mechanism of action of the inhibitor on intact mitochondria is offered. 相似文献