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1.
2.
N. Y. Yalcin-Mendia M. Ipek H. Kacan S. Curuk N. Sari S. Cetiner V. Gaba 《Journal of plant biochemistry and biotechnology.》2003,12(2):147-150
The optimization of regeneration protocol for different genotypes increases the yield in transformation studies. Cotyledon explants of watermelon [Citrullus lanatus (Thunb) Matsum & Nakai] cv Crimson Sweet were cultured on MS medium containing combinations of benzyl adenine (BA) (0, 5, 10, 20 µM) and indole-3-acetic acid (IAA) (0, 0.5, 5 µM). Maximum shoot growth and subsequent rooting from explants on regeneration medium were obtained from the media containing 10 µM BA + 0.5 µM IAA and 20 µM BA (75 and 78%) by direct organogenesis, respectively. Histological analysis showed that cell division was observed in the epidermal and subepidermal layers. Protuberant structures were observed in tissues between 7 and 12 days in culture. Meristematic structures were observed after 12days in culture which later developed into buds. 相似文献
3.
High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans 总被引:1,自引:0,他引:1
We compared male-reproductive-tract polypeptides of Drosophila melanogaster
and D. simulans by using two-dimensional gel electrophoresis. Approximately
64% of male-reproductive-tract polypeptides were identical between two
randomly chosen isofemale lines from these two species, compared with 83%
identity for third-instar imaginal wing-disc polypeptides. Qualitatively
similar differences were found between reproductive tracts and imaginal
discs when D. sechellia was compared with D. melanogaster and with D.
simulans. When genic polymorphism was taken into account, approximately 10%
of male- reproductive-tract polypeptides were apparently fixed for
different alleles between D. melanogaster and D. simulans; this proportion
is the same as that found for soluble enzymes by one-dimensional gel
electrophoresis. Strikingly, approximately 20% of male-reproductive- tract
polypeptides of either D. melanogaster or D. simulans had no detectable
homologue in the other species. We propose that proteins of the Drosophila
male reproductive tract may have diverged more extensively between species
than have other types of proteins and that much of this divergence may
involve large changes in levels of polypeptide expression.
相似文献
4.
5.
Hanna Ebeling Tuulikki Porkka Varpu Penninkilampi-Kerola Eija Berg Sari J?rvi Irma Moilanen 《Twin research》2003,6(4):334-343
We evaluated dominance-submissiveness between co-twins and its relationship to mental health in a cohort study of 419 twins followed from pregnancy to 22-30 years of age. Dominance-submissiveness between co-twins was assessed from three separate perspectives: physical dominance, psychological dominance, and verbal dominance. Depressive, nervous, and psychosomatic symptoms were analyzed in different twin groups. In the physical domain, males were more commonly dominant than females at school age and in adulthood. Before and at school age, girls were more dominant than boys in the psychological and verbal domains, as well as in total dominance. These differences disappeared in adulthood, and 81% of adult twins felt themselves equal to their co-twin in total dominance. Submissiveness in the psychological domain seemed to be associated with increased depressiveness, nervous complaints and psychosomatic symptoms in males of male-female twin pairs. Verbally submissive males in same-sex twin pairs had more depression and psychosomatic symptoms. Among females of same-sex twin pairs, submissiveness in the psychological domain was most clearly associated with depressive symptoms, whereas psychological or verbal dominance-submissiveness among females from male-female twin pairs was not associated with symptoms. Psychologically dominant males and females of same-sex twin pairs expressed greater nervousness than did their co-twins. We conclude that being submissive, especially in the psychological domain, to a female twin partner seems to be stressful, whereas it is easier, especially for females, to be submissive to a male twin partner. 相似文献
6.
The effects of aluminium chloride (AICI3) treatments (50 and 150 mg/l) on 3-year-old Scots pine (Pinus sylvestris L.) seedlings were studied in a sand culture during 2 growing periods in an open field experiment. Even by the end of the
first growing period, a decline was observed in the concentrations of Ca, Mg and P within the needles, and of Ca and Mg in
the roots. After the second growing period, increased N and K concentrations were observed in the needles of Al-treated seedlings.
Both the needles and roots of Al-treated seedlings showed, after the second growing period, a decline in growth and increased
concentrations of AI as the amount of AICI3 in the nutrient solution increased. Al-induced changes in needle structure were
found to be symptomatic of a nutrient imbalance, particularly of Mg and P. Al-stress did not result in any observable changes
in root anatomy or in the number of mycorrhizas. Scots pine proved to be rather resistant to Al-stress, indicating that direct
Al-injuries are not likely in the field, though Al-stress may be a contributing factor in the formation of nutrient imbalances. 相似文献
7.
In the presence of acetyl phosphate, approximately 0.8 extra sulphydryl groups/105 g protein of sarcoplasmic reticulum membrane vesicles are exposed to reaction with -ethylmaleimide, whereas in the presence of ATP approximately 0.6 groups/105 g protein are protected. Dithiobis (nitrobenzoic acid) reacts with the membrane sulphydryl groups more slowly in the presence of ATP than in the presence of acetyl phosphate or in the absence of substrate. Sarcoplasmic reticulum membrane is degraded by trypsin at a faster rate than normal when acetyl phosphate is present as seen from changes in electrophoretic patterns, ATPase activity and Ca2+ uptake capacity, and at a slower rate when ATP is present as seen from the last two properties. These differences in reactivity are interpreted as being due to differences in membrane conformations induced by the two substrates. 相似文献
8.
Catalytic activities of human liver cytochrome P-450 IIIA4 expressed in Saccharomyces cerevisiae 总被引:2,自引:0,他引:2
W R Brian M A Sari M Iwasaki T Shimada L S Kaminsky F P Guengerich 《Biochemistry》1990,29(51):11280-11292
A human liver cytochrome P-450 (P-450) IIIA4 cDNA clone was inserted behind an alcohol dehydrogenase promoter in the plasmid vector pAAH5 and expressed in Saccharomyces cerevisiae (D12 and AH22 strains). A cytochrome P-450 with typical spectral properties was expressed at a level of approximately 8 x 10(5) molecules/cell in either strain of yeast. The expressed P-450 IIIA4 had the same apparent monomeric Mr as the corresponding protein in human liver microsomes (P-450NF) and could be isolated from yeast microsomes. Catalytic activity of the yeast microsomes toward putative P-450 IIIA4 substrates was seen in the reactions supported by cumene hydroperoxide but was often lower and variable when supported by the physiological donor NADPH. The catalytic activity of purified P-450 IIIA4 was also poor in some systems reconstituted with rabbit liver NADPH-P-450 reductase and best when both the detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate and a lipid extract (from liver or yeast microsomes) or L-alpha-1,2-dilauroyl-sn-glycero-3-phosphocholine were present. Under these conditions the expressed P-450 IIIA4 was an efficient catalyst for nifedipine oxidation, 6 beta-hydroxylation of testosterone and cortisol, 2-hydroxylation of 17 beta-estradiol and 17 alpha-ethynylestradiol, N-oxygenation and 3-hydroxylation of quinidine, 16 alpha-hydroxylation of dehydroepiandrosterone 3-sulfate, erythromycin N-demethylation, the 10-hydroxylation of (R)-warfarin, the formation of 9,10-dehydrowarfarin from (S)-warfarin, and the activation of aflatoxins B1 and G1, sterigmatocystin, 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (both + and - diastereomers), 3,4-dihydroxy-3,4-dihydrobenz[a]anthracene, 3,4-dihydroxy-3,4-dihydro-7, 12-dimethylbenz[a]anthracene, 9,10-dihydroxy-9,10-dihydrobenzo[b]fluoranthene, 6-aminochrysene, and tris(2,3-dibromopropyl) phosphate to products genotoxic in a Salmonella typhimurium TA1535/pSK1002 system where a chimeric umuC' 'lacZ plasmid is responsive to DNA alkylation. Reaction rates were stimulated by 7,8-benzoflavone and inhibited by rabbit anti-P-450 IIIA (anti-P-450NF), troleandomycin, gestodene, and cimetidine. Evidence was obtained that rates of reduction of ferric P-450 IIIA4 in yeast microsomes and the reconstituted systems are slow and at least partially responsible for the lower rates of catalysis seen in these systems (relative to liver microsomes). The results of these studies with a defined protein clearly demonstrate the ability of P-450 IIIA4 to catalyze regio- and stereoselective oxidations with a diverse group of substrates, and this enzyme appears to be one of the most versatile catalysts in the P-450 family. 相似文献
9.
Irradiation of the kinetochore region of PtK2 chromosomes by laser light of 532 nm was used to study the function of the kinetochore region in chromosome movement and
to create artificial micronuclei in cells. When the sister kinetochores of a chromosome were irradiated at prometaphase, the
affected chromosome detached from the spindle and exhibited no further directed movements for the duration of mitosis. The
chromatids of the chromosome remained attached to one another until anaphase, at which point they separated. No poleward movement
of the chromatids was observed, and at telophase they passively moved to one of the daughter cells and were enclosed in a
micronucleus. The daughter cell containing the micronucleus was then isolated by micromanipulation and followed through subsequent
mitoses. At the next mitosis, two chromosomes, each with two chromatids, condensed in the micronucleus. These chromosomes
did not attach to the spindle and showed chromatid separation, but no poleward movements at anaphase. They were again enclosed
in micronuclei at telophase. The third generation mitosis was similar to the second.
Occasionally, both the irradiation-produced and naturally occurring micronuclei exhibited no chromosome condensation at mitosis.
Feulgenstained monolayers of PtK2 cells with naturally occurring micronuclei showed that some micronuclei stain positive for DNA and others do not. This finding
raises questions about the fate of chromosomes in a micronucleus. 相似文献
10.
Ayaka Komatsu Izumi Iida Yusuke Nasu Genki Ito Fumiko Harada Sari Kishikawa Stephen J. Moss Takeyasu Maeda Miho Terunuma 《The Journal of biological chemistry》2022,298(5)
Hyperammonemia is known to cause various neurological dysfunctions such as seizures and cognitive impairment. Several studies have suggested that hyperammonemia may also be linked to the development of Alzheimer’s disease (AD). However, the direct evidence for a role of ammonia in the pathophysiology of AD remains to be discovered. Herein, we report that hyperammonemia increases the amount of mature amyloid precursor protein (mAPP) in astrocytes, the largest and most prevalent type of glial cells in the central nervous system that are capable of metabolizing glutamate and ammonia, and promotes amyloid beta (Aβ) production. We demonstrate the accumulation of mAPP in astrocytes was primarily due to enhanced endocytosis of mAPP from the plasma membrane. A large proportion of internalized mAPP was targeted not to the lysosome, but to the endoplasmic reticulum, where processing enzymes β-secretase BACE1 (beta-site APP cleaving enzyme 1) and γ-secretase presenilin-1 are expressed, and mAPP is cleaved to produce Aβ. Finally, we show the ammonia-induced production of Aβ in astrocytic endoplasmic reticulum was specific to Aβ42, a principal component of senile plaques in AD patients. Our studies uncover a novel mechanism of Aβ42 production in astrocytes and also provide the first evidence that ammonia induces the pathogenesis of AD by regulating astrocyte function. 相似文献