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1.
Romuald Czerpak Alicja Piotrowska Paweł Dobrzyń Andrzej Tatur Monika Marczuk 《Acta Physiologiae Plantarum》2003,25(3):271-278
The present study was undertaken to determine the influence of biochanin A, isoflavone characterised by estrogenic activity,
upon the content of chlorophylls and carotenoids in the cells of green alga Chlorella vulgaris Beijerinck (Chlorophyceae). On the 6th day of cultivation under the influence of 10−6 M biochanin A exerted the greatest biological activity and the most stimulating effect on the analysed parameters: growth
of the alga expressed by the cells number and the content of photosynthetic pigments in them. The total content of carotenoids
was stimulated on the 6th day of experiment in the range of 197 % but during the 9th day only in 179 % in comparision with the control group (100 %). At the same time content of carotenes increased to the level
of 123 – 119 % and xanthophylls to 208 – 178 %. Among the carotenes, β-carotene was characterised with the 3.7 times higher
content in regard to the content of α-carotene on the 6th day of cultivation and during the 9th day — the 5.7 times domination. The content of xanthophylls that contain two atoms of oxygene in molecule (oxygen — poor
xanthophylls) was intensively stimulated in the range of 224 %. Moreover, the oxygen — rich xanthophylls content reached the
value 179 % when compared to the control. The greatest stimulation of the content of chlorophylls and its isomers was observed
during the 3rd day of cultivation of Chlorella vulgaris when it rose up to 166 % and to 156 % on the 6th day. The content of chlorophyll b and its isomers was stimulated in 181 % on the 6th day of culture and 155 % during the 9th day of algal culture. The evidence on the stimulating effect of biochanin A as the main representative of isoflavones on
the growth and content photosynthetic pigments in eucaryotic alga C. vulgaris was demonstrated in these studies. 相似文献
2.
The development of Gryllus argentinus Sauss. was studied under stable laboratory conditions: the temperature of 26°C, the air humidity of 60%, and the photoperiod
of 12h light: 12 h dark. The life cycle of Gryllus argentinus includes four stages: egg, pronymph, nymph, and adult. The duration of embryonic development is 18 days. The depth of egg
bedding in the peat is 9.63 ± 0.12 mm (n =145), the clutch containing 2–4 eggs. A female can lay over 1100 viable eggs during the entire oviposition period. Nymphal
development includes 9 instars and lasts 97 days. The duration of nymphal instars (days) is: I—5; II—6; III—6; IV—6; V—8;
VI—10; VII—13; VIII—14; IX—29. The duration of the adult life is 51 days in males and 69 days, in females. In the imaginal
ontogenesis of males and females, three periods can be distinguished: pre-reproductive, reproductive, and postreproductive.
Males start to emit the aggressive signal on the 6th (5–8th) day (the pre-reproductive period). They enter the reproductive
period (start to emit the calling song) on the 9th (8–13th) day. Females enter the reproductive period (become capable of
responding to the calling song and of copulation) on the 9th (8–10th) day. Oviposition starts on the day after the first copulation.
The reproductive period lasts about 40 (15–59) days in males and 58 (21–70) days in females. The post-reproductive period
starts in females at the moment of finishing the egg laying period and in males, with disappearance of reproductive behavior.
The period ends in the animal’s death. 相似文献
3.
Dmitriev LF 《Neurochemical research》2007,32(8):1278-1291
Polyunsaturated fatty acids (PUFA) and α-tocopherol (α-TOH) are the most oxygen-sensitive constituents of cells. α-TOH is
a member of the vitamin E family that is considered the most important lipophilic antioxidant in cell membranes. Its importance
is emphasized by the involvement of oxidative stress in injury to the central nervous system and neurodegenerative diseases.
Currently, α-TOH transfer protein (TTP), is believed to play a significant role in maintaining the vitamin status but the
presence of α-TOH in membranes is required but not sufficient to protect the membranes against lipid hydroperoxides (LOOH)
formation. The lipid-radical theory presented in this review considers the role of two membrane factors—α-tocopherol and cytochrome
b5; these factors secure the functioning of lipid-radical cycles and the participation of lipid-radical reactions in the key
membrane processes. The prominent intermembrane reaction realized via a protein–lipid interaction, during which electron transport
from cytochrome b5—located in the outer membrane—to peroxyl radical (LOO·)—located in inner membrane—causes reduction of the peroxyl radical: cyt.b5red + LOO· → cyt.b5ox + LOO−. This secures an interaction of α-TOH with other intermediate, LOO− excepting the LOOH formation. The discussion will be focused on the consequences of ineffective electron transfer to LOO· and excessive oxidative pathway of metabolism of the PUFA (LOO· → LOOH). Assuming the operation of cytochrome b5/α-tocopherol-controlled lipid-radical cycles and considering the role of the cycles in membrane bioenergetics we arrive
at a model for effective function of adenine nucleotide translocator and ATP synthesis in mitochondria. This paper summarizes
our experimental evidence that the oxidative and non-oxidative pathways of metabolism of PUFA via their respective intermediates
occur in the cells. While this fact is not widely appreciated it may be relevant to elucidation of new mechanisms of neurodegenerative
diseases. 相似文献
4.
Competition between granulosis virus (GV) and the larval parasite,Sturmiopsis inferens Tns. (Tachinidae: Diptera), was studied in 3rd — and 4th — instar larvae of the sugarcane shoot borer,Chilo infuscatellus Snellen (Crambidae: Lepidoptera), under laboratory conditions. Mortality due to GV infection and parasitization was 76.8 and 47.6 per cent, respectively,
when they were tested separately. But when hosts were infected simultaneously with microfeeding of GV and larval parasite,
a significantly low parasitism (5.5%) was obtained compared to 74.8 per cent mortality by GV infection. When the larvae were
microfed with the GV 6 days after inoculation with parasitic maggots, mortality due to the virus was reduced significantly
to 20.5 per cent, but when the maggot inoculation was preceded by virus microfeeding 6 days before, parasitization was unsuccessful,
while 75% of larvae died of virus. Results obtained from field — collected larvae also showed that significantly more parasite
puparia were recovered from healthy larvae than from virus — infected larvae. Similar differences in parasitization were not
obtained in the case of healthy or virus — infected pupae.
相似文献
5.
The parathyroid hormone type 1 receptor (PTHR1) mediates the actions of parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHRP). Interacting with this receptor, PTHRP contributes to skeletal development through the regulation of chondrocyte proliferation and differentiation. Recently, a tetranucleotide repeat—(AAAG)
n
—in the P3 promoter of the PTHR1 gene has been shown to have functional activity in vitro, and homozygosity for (AAAG)6, or the 6/6 genotype, has been associated with greater adult height compared to the 5/5 genotype. In this study, we evaluated the association of (AAAG)
n
with height and bone mineral density (BMD) measured at lumbar spine (LS) and femoral neck (FN) in a cohort of 677 young caucasian women 18–35 years of age. Genomic DNA was amplified and genotyped by comparison with sequenced controls following electrophoretic separation through high-resolution polyacrylamide gels. Allele frequencies for (AAAG)
n
were: 76.8% (n=5); 20.9% (n=6); 1.8% (n=7); 0.18% (n=8); 0.27% (n=9); 0.08% (n=2), and there was no evidence for Hardy–Weinberg disequilibrium. Analysis of variance showed that subjects bearing one or two (AAAG)6 alleles (6/X & 6/6) were significantly taller (165.7±0.5 cm) than the others (X/X, 164.5±0.3 cm; P=0.034). This association was significant after adjusting for multiple covariates—current age, age at menarche, physical activity, smoking status, and intakes of caffeine and calcium. Comparison of genotype groups for BMD was not significant at LS, but BMD was significantly higher at FN in the group with at least one (AAAG)6 allele (adjusted means: 1.021±0.008 vs. 0.999±0.006 g/cm2, P=0.032). In conclusion, our data show that subjects bearing one or two (AAAG)6 alleles are taller than subjects without, reinforcing the notion that in vivo variation in promoter activity of the PTHR1 gene may be a relevant genetic influence on final adult height and BMD. 相似文献
6.
The murine CC chemokine, 6C-kine, inhibits tumor growth and angiogenesis in a human lung cancer SCID mouse model 总被引:5,自引:0,他引:5
Arenberg DA Zlotnick A Strom SR Burdick MD Strieter RM 《Cancer immunology, immunotherapy : CII》2001,49(11):587-592
The recently described CC chemokine, 6C-kine, is unique in that it contains -six rather than the usual four conserved cysteines
typical of this family. Furthermore, murine 6C-kine binds to one of the CXC chemokine receptors CXCR3, in addition to its
other known receptor CCR7. We have shown that two other ligands of CXCR3, IP-10 and MIG, are potent inhibitors of tumor growth
in severe combined immunodeficiency (SCID) mice. We postulated that murine 6C-kine may also inhibit tumor growth via inhibition
of angiogenesis in this model. SCID mice (n=6 per group) inoculated with A549 human lung cancer cells were treated with either 6C-kine (100 ng intra-tumor injection
every other day) or control protein for 8 weeks. Tumors from murine 6C-kine-treated mice (288 ± 26 mm3) were significantly smaller than tumors from control treated mice (788 ± 156 mm3, P=0.005). Additionally, murine 6C-kine reduced metastases compared with controls (0.5 ± 0.3 vs 3.0 ± 1.2 metastases per animal,
P=0.05). Tumor vascularity (as assessed by vessel density counting) was reduced in murine 6C-kine-treated mice compared with
controls. Murine 6C-kine had no direct effect on proliferation of A549 cells, and there were no differences in the infiltration
of leukocyte sub-populations, assessed by flow cytometry, in the treatment groups. Interestingly, human 6C-kine, unlike murine
6C-kine, does not bind CXCR3 and had no anti-tumor effect in the same model. These data suggest that murine 6C-kine has anti-tumor
effects independent of its leukocyte-recruiting activity. Furthermore, while not confirmatory, these data lend further support
to the fact that CXCR3 may be the receptor for angiostatic CXC chemokines.
Received: 15 June 2000 / Accepted: 18 August 2000 相似文献
7.
Tatiana Kugelmeier Rodrigo del Rio do Valle Marcelo Alcindo de Barros Vaz Guimarães José Augusto Pereira Carneiro Muniz Frederico Ozanan Barros Monteiro Cláudio Alvarenga de Oliveira 《International journal of primatology》2011,32(3):605-615
A better understanding of a species’ reproductive physiology can help conservation programs to manage primates in the wild
and develop assisted reproductive technologies in captivity. We investigated whether measurements of fecal progestin and estrogen
metabolites obtained by a radioimmunoassay could be used to monitor the ovarian cycle of Alouatta caraya. We also compared the occurrence of vaginal bleeding with the hormone profiles. We collected fecal samples from 3 adult and
1 subadult captive female over 5 mo and performed vaginal cytology for the adults. The interval between fecal progestin surges
in the adult females was 19.11 ± 2.14 d (n = 18 cycles). Fecal progestin concentrations remained at basal values for 9.83 ± 2.21 d (n = 18) and rose to elevated values for 9.47 ± 0.72 d (n = 19). The subadult female showed basal levels of fecal estrogen and progestin concentrations throughout the study, suggesting
that our hormone measurements are valid to monitor the ovarian cycle. Bleeding periods coincided with basal levels of fecal
estrogens and progestin at intervals of 19.8 ± 0.9 d and lasted for 4.1 ± 1.0 d. Although we obtained these data from only
3 individuals, the results indicate that this species likely has a menstrual-type ovarian cycle. These data provide the first
endocrine profile for the Alouatta caraya ovarian cycle and are similar to results obtained for other howler species. This similarity is important for comparative
studies of howlers, allowing for a better understanding of their reproductive physiology and contributing to a critical information
base for managing Alouatta species. 相似文献
8.
DNA amounts have been determined in the micronuclei and macronuclei of 8 strains ofParamecium aurelia and 6 strains ofTetrahymena pyriformis. In the case ofTetrahymena a distribution of values for the amount of DNA in the macronuclei of all the strains was observed but the lowest values were
approximately the same, viz. 1.17×10−11
g. There are two groups of strains in relation to micronuclear DNA values ofTetrahymena, one giving an average of 0.36×10−12 g and the other 0.815×10−12 g. The ratio of MIC/MAC DNA varies in the two groups.Paramecium again has a range of macronuclear values within each stock—lowest value 2.51×10−10 g—and the micronuclear values are similar in all stocks—approximately 0.613×10−12 g. The ratio of MIC/MAC DNA is similar in each stock.—The haploid genome values calculated from these data show excellent
agreement with the values obtained by DNA renaturation studies.
Supported by a Research Grant B/SR/8276 from the Science Research Council. The Vickers densitometer was purchased with a grant
from the Medical Research Council. 相似文献
9.
Saniova B Drobny M Lehotsky J Sulaj M Schudichova J 《Cellular and molecular neurobiology》2006,26(7-8):1473-1480
1. The main idea of the open clinical trial was to compare the income and outcome clinical picture and the evolution of the biochemical markers in the defined intervals in closed head injury group patients.2. In the group of 32 patients, mean age 40.78±15.36 years suffering from closed traumatic brain injury the following markers were measured: glycaemia, malondialdehyde (MDA) as marker of lipid peroxidation, beta-caroten, total SH groups as marker of protein oxidation in the following intervals: between the 1st and the 3rd, between the 3rd and the 7th, between the 1st and the 7th day respectively.3. Glycaemia significantly decreased since the 1st day till the 3rd day (p < 0.05) and since the 1st day till the 7th day (p < 0.05) but it was not significantly changed since the 3rd day till the 7th day (p > 0.05).4. MDA 1st × MDA 3rd p > 0.05 insignificant change, MDA 1st × MDA 7th p < 0.001—high significant decrease, MDA 3rd × MDA 7th—p < 0.0001—very high significant decrease.5. Beta-caroten the 1st × beta-caroten the 3rd day was insignificantly changed—p > 0.05, the 3rd × the 7th day beta-caroten increased significantly—p < 0.0002, the 1st day × 7th day beta-caroten significantly increased—p < 0.0001.6. We examined the SH groups only in nine patients, due to technical problems and SH groups decrease on the 3rd day (p < 0.005).7. In 18 amantadine sulphate subgroups (randomly selected), there was 5.5% lethality and mean outcome GCS (outGCS) 9.83±3.8, while lethality of the control subgroup (n=14) was 42.9%, mean outGCS 6.28±3.5. 相似文献
10.
α-Amylase isozymes were detected via electrophoretic separation in a Tris-glycine polyacrylamide gel system (pH 8.4). Three
chromosome 6B loci controlling the α-amylase isozyme composition were identified by studying the grain α-amylase patterns
in an F→∞ self-pollinating population of winter common wheat (Donskoi Mayak). The loci were found to take the following order in the
long arm of chromosome 6B: cen. cen.—α-Amy-B3—α-Amy-B6—α-Amy-B1 相似文献
11.
D. I. Bashmakov N. A. Pynenkova K. A. Sazanova A. S. Lukatkin 《Russian Journal of Plant Physiology》2012,59(1):59-64
We studied the influence of a synthetic cytokinin-like growth regulator (Cytodef) and heavy metal ions—Pb2+, Sr2+, Zn2+, and Ni2+—on generation of superoxide anion (O2⊙−), lipid peroxidation, and carotenoids content in leaves of 7-day-old cucumber plants (Cucumis sativus L., cv. Izyashchnyi). In some instances Cytodef reduced the toxicity of heavy metals: it mitigated the negative effect of
metals on oxidative processes and elevated the concentration of antioxidants (carotenoids). 相似文献
12.
Rob Uche Onyenwoke R. Geyer Juergen Wiegel 《Extremophiles : life under extreme conditions》2009,13(4):687-693
An NAD(P)H-dependent oxidoreductase has been purified approximately 40-fold from the soluble protein fraction of the dissimilatory
iron-reducing, anaerobic, thermophilic bacterium Carboxydothermus ferrireducens. The enzyme, a flavoprotein, has broad-substrate specificity—reducing Fe3+, Cr6+, and AQDS with rates of 0.31, 0.33, and 3.3 U mg−1 protein and calculated NADH oxidation turnover numbers of 0.25, 0.25, and 2.5 s−1, respectively. Numerous quinones are reduced via a two-electron transfer from NAD(P)H to quinone, thus participating in managing
oxidative stress by avoiding the formation of semiquinone radicals. 相似文献
13.
Kaname Isozaki Hidehiko Fukahori Takeshi Honda Naoto Shirasu Kazushi Okada Takeru Nose Kazuyasu Sakaguchi Yasuyuki Shimohigashi 《International journal of peptide research and therapeutics》2003,10(5-6):511-522
The S-3-nitro-2-pyridinesulfenyl (SNpys) group in an affinity ligand can bind to a free thiol group of a cysteine residue in a
target receptor molecule, forming a disulfide bond via the thiol-disulfide exchange reaction. SNpys-containing Leu-enkephalin
analogues of [-Ala2, Leu5]-enkephalyl-Cys(Npys)6 and [-Ala2,Leu(CH2SNpys)5]enkephalin, and dynorphin A analogues of [-Ala2,Cys(Npys)12]dynorphin A-(1-13) amide and [-Ala2,Cys(Npys)8]dynorphin A-(1-9) amide have been found to affinity-label all of the δ, μ (rat brain), and κ (guinea pig brain) opioid receptor subtypes. In this study, using these chemically synthesized SNpys-containing analogues,
we attempted to identify the analogues that affinity-label the cysteine residue at position 60 of the δ opioid receptor. We first established the assay procedure, principally based on the receptor binding assay to use COS-7 cells
expressing the δ opioid receptor. Then, using a mutant δ receptor with the Cys60→Ala substitution, we assayed the SNpys-containing analogues for their specific affinity-labeling. [-Ala2,Cys(Npys)12]dynorphin A-(1-13) amide was found to have drastically reduced labeling activity for this mutant receptor as compared to
its activity for the wild-type δ receptor. Other analogues exhibited almost the same activity for both the wild-type and mutant δ receptors. These results indicate that the δ-Cys60 residue has a free thiol group, which is labeled by [-Ala2,Cys(Npys)12]dynorphin A-(1-13) amide. 相似文献
14.
D. V. Klochkov P. A. Eryuchenkov 《Journal of Evolutionary Biochemistry and Physiology》2000,36(2):170-177
The responsess of the mink reproductive systems in October to a single intramuscular injection of chorionic gonadotropin (CG,
Profasi R, Italy) at doses of 10, 20, 50, and 100 IU was studied. The estrous cycle state, folliculogenesis, and reproductive
parameters of the female minks were estimated. To evaluate functional polymorphism in the reproductive system of the females
in response to the CG injection, a dose of 20 IU was chosen. On the sixth day after administration of this dose of CG, the
females (n = 185) were distributed according to the stages of the estrous cycle as follows: anestrus—71 animals (38.4%), anestrus-proestrus—37
(20.0%), proestrus—30 (16.2%), proestrus-estrus—14 (7.6%), estrus—33 (17.8%). In the females of the “anestrus-proestrus” and
“proestrus” groups as compared with the other groups as well as with control, a statistically significantly higher fertility
was revealed. The study of folliculogenesis in the females with different parameters of the estrous cycle in November demonstrated
the high level of fertility to be due to ability of these females to produce, under influence of the CG injection, the maximal
number of mature follicles. A high heritable responsiveness of the reproductive system of the females to the CG injection
(coefficient of realized heritabilityh = 0.64; the calculation made on the data for the sisters) indicates that this method may be an additional criterion in the
selection of females for fertility. 相似文献
15.
Two-step concerted mechanism for alkane hydroxylation on the ferryl active site of methane monooxygenase 总被引:1,自引:0,他引:1
Kazunari Yoshizawa 《Journal of biological inorganic chemistry》1998,3(3):318-324
A two-step concerted mechanism for the conversion of methane to methanol catalyzed by soluble methane monooxygenase (sMMO)
is discussed. We propose that the enzymatic reaction mechanism is essentially the same as that of the gas-phase methane-methanol
conversion by the bare FeO+ complex. In the initial stage of our mechanism, the ferryl (Fe—O) "iron" active site of intermediate Q and substrate methane come into contact to form the initial Q (CH4) complex with an OFe—CH4 bond. The C—H bonds of methane are significantly weakened by the formation of a five-coordinate carbon species, through orbital
interactions between a C
3v
- or D
2d
-distorted methane and the Fe—O active site. The important transition state for an H atom abstraction exhibits a four-centered
structure. The generated intermediate involves an HO—Fe—CH3 moiety, and it is then converted into the final product complex including methanol as a ligand through a methyl migration
that occurs via a three-centered transition state. The two-step concerted mechanism is consistent with recent experiments
on regioselectivity of enzyme-catalyzed alkane hydroxylations.
Received: 15 September 1997 / Accepted: 20 December 1997 相似文献
16.
Clostridium aminobutyricum ferments 4-aminobutyrate (γ-aminobutyrate, GABA) to ammonia, acetate and butyrate via 4-hydroxybutyrate that is activated
to the CoA-thioester catalyzed by 4-hydroxybutyrate CoA-transferase. Then, 4-hydroxybutyryl-CoA is dehydrated to crotonyl-CoA,
which disproportionates to butyryl-CoA and acetyl-CoA. Cocrystallization of the CoA-transferase with the alternate substrate
butyryl-CoA yielded crystals with non-covalently bound CoA and two water molecules at the active site. Most likely, butyryl-CoA
reacted with the active site Glu238 to CoA and the mixed anhydride, which slowly hydrolyzed during crystallization. The structure
of the CoA is similar but less stretched than that of the CoA-moiety of the covalent enzyme-CoA-thioester in 4-hydroxybutyrate
CoA-transferase from Shewanella oneidensis. In contrast to the structures of the apo-enzyme and enzyme-CoA-thioester, the structure described here has a closed conformation,
probably caused by a flip of the active site loop (residues 215–219). During turnover, the closed conformation may protect
the anhydride intermediate from hydrolysis and CoA from dissociation from the enzyme. Hence, one catalytic cycle changes conformation
of the enzyme four times: free enzyme—open conformation, CoA+ anhydride 1—closed, enzyme-CoA-thioester—open, CoA + anhydride-2—closed,
free enzyme—open. 相似文献
17.
Inhibition of galectin-3 mediated cellular interactions by pectic polysaccharides from dietary sources 总被引:1,自引:0,他引:1
Pectic polysaccharides from dietary sources such as Decalepis hamiltonii—swallow root (SRPP), Hemidesmus indicus (HPP), Nigella sativa—black cumin (BCPP), Andrographis serpyllifolia—(APP), Zingiber officinale—ginger (GRPP) and, citrus pectin (CPP) were examined for galectin inhibitory activity. Inhibition of (a) galectin-3 of MDA-MB-231
cells induced hemagglutination of red blood cells; (b) galectin-3 mediated interaction between normal/metastatic human buccal
cells (NBC)/(MBC) and; (c) invasion of MDA-MB-231 and MBC in the invasive chamber was assessed. Results indicated that SRPP
inhibited hemagglutination at Minimum Inhibitory Concentration (MIC) of 1.86 μg ml−1 equivalent of carbohydrate as apposed to those of BCPP (130 μg ml−1), APP (40 μg ml−1), HPP (40 μg ml−1) and CPP (25 μg ml−1). GRPP even at concentration >1–6 mg ml−1 did not inhibit agglutination. Also SRPP showed ∼15 and 2 fold potent anti hemagglutination activity relative to that of
galectin-3 specific sugars—galactose (MIC-27.1 μg ml−1) and lactose (MIC-4.16 μg ml−1) respectively. Further, SRPP at 10 μg ml−1 inhibited agglutination of NBC by galectin-3 of MDA-MB-231 cells. Modified swallow root pectic polysaccharide (MSRPP) of
50 kDa retained anti hemagglutination activity (MIC of 1.03 μg ml−1) and inhibited MDA-MB-231 and MBC invasion by 73 and 50% with an IC50 of 136 and 200 μg ml−1 respectively. Both SRPP and MSRPP induced apoptosis up to 80% at 100 μg ml−1 concentration by activating ∼2 and 8 folds of Caspase-3 activity. Sugar composition analysis and its correlation with the
galectin inhibitory property indicated that pectic polysaccharides with higher arabinose and galactose content—arabinogalactan
inhibited hemagglutination significantly. 相似文献
18.
Anna Janeczko Maciej Kocurek Izabela Marcińska 《Central European Journal of Biology》2012,7(5):902-909
The aim of the present studies was to assess the possibility of compensating the negative effects of drought stress on gaseous exchange and efficiency of photosystem II in soybean seedlings by application of the androgen — androstenedione. Androstenedione (0.25 mg dm−3) was applied via presowing seed soaking (12 h). Control seeds were untreated with steroid. Plants were cultured in pots. On the 12th day of growth, the plants were watered for the last time. Drought symptoms occurred during the next 10 days. On the 22nd day of growth, leaf gaseous exchange and PSII measurements were taken. Afterwards the plants were watered. Two days later measurements were taken again. Androstenedione improved the intensity of leaf net photosynthesis. The effect of androstenedione was manifested during the rehydration of plants that have undergone a period of drought. An increase in net photosynthesis intensity was accompanied by higher transpiration. Possible mechanisms of androstenedione action — effect on aquaporin functionality and membrane stability — are discussed. The significance of ethanol and DMSO (solvents of steroid) in experiments on the physiological activity of androstenedione is also considered. 相似文献
19.
Ely Zayova Ira Stancheva Maria Geneva Maria Petrova Rumiana Vasilevska-Ivanova 《Central European Journal of Biology》2012,7(4):698-707
An effective in vitro protocol for rapid clonal propagation of Echinacea purpurea (L.) Moench through tissue culture was described. The in vitro propagation procedure consisted of four stages: 1) an initial stage - obtaining seedlings on Murashige and Skoog (MS) basal
medium with 0.1 mg L−1 6-benzylaminopurine, 0.1 mg L−1 α-naphthalene acetic acid and 0.2 mg L−1 gibberellic acid; 2) a propagation stage — shoot formation on MS medium supplemented with 1 mg L−1 6-benzylaminopurine alone resulted in 9.8 shoots per explant and in combination with 0.1 mg L−1 α-naphthalene acetic acid resulted in 16.2 shoots per explant; 3) rooting stage — shoot rooting on half strength MS medium
with 0.1 mg L−1 indole-3-butyric acid resulted in 90% rooted microplants; 4) ex vitro acclimatization of plants. The mix of peat and perlite was the most suitable planting substrate for hardening and ensured
high survival frequency of propagated plants. Significant higher levels were observed regarding water-soluble and lipid-soluble
antioxidant capacities (expressed as equivalents of ascorbate and α-tocopherol) and total pnenols content in extracts of Echinaceae flowers derived from in vitro propagated plants and adapted to field conditions in comparison with traditionally cultivated plants. 相似文献
20.
The impact of population dynamics on Y-chromosome microsatellite polymorphism. Mathematical modeling
In this article, we use mathematical modeling to study the impact of population dynamics on Y-chromosome STR-polymorphism accumulation in two independently evolving populations, namely, on the changes in genetic distance between the populations. Comparative analysis using two definitions of genetic distance—(δμ)2 and ASD—shows that, in contrast to (δμ)2, ASD is almost linearly dependent on time (except for sparse stationary populations, where deviations are observed). When the population numbers undergo oscillations, ASD proves to be smaller than that for stationary populations. 相似文献