共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
《Inorganica chimica acta》1988,146(2):249-254
Lawrencium (3-min 260Lr) together with other actinides, was produced in the bombardment of a 249Bk target with 18O ions. There was no sign of a reduction of Lr3+ in dilute hydrochloric acid by V2+ or Cr2+, although in the same experiments, Md3+ was reduced to Md2+ (E°=−0.2 V). The resulting limit for the reduction potential of the Lr3+/Lr1(2)+ couple is E° < −0.44 V. 相似文献
4.
5.
6.
7.
8.
Feeding of planktonic rotifers on ciliates: a method using natural ciliate assemblages labelled with fluorescent microparticles 总被引:1,自引:0,他引:1
Joaquim-Justo Celia; Detry Cedric; Caufman Fabrice; Thome Jean-Pierre 《Journal of plankton research》2004,26(11):1289-1299
A method was developed to allow direct measurements of predationexerted by metazooplankton on ciliates. The method relied onthe use of ciliates labelled with fluorescent microparticles(FMP). Optimal labelling conditions were determined with ciliatesfrom cultures (Tetrahymena pyriformis) and with natural ciliateassemblages sampled in a river. Labelled T. pyriformis wereused as tracer food to determine gut passage time (GPT) andingestion rates of the rotifer Brachionus calyciflorus in thelaboratory. Predation of metazooplankton from the lowland riverMeuse (Belgium) was determined by labelling natural assemblagesof ciliates and using them as tracer food for metazooplankterssampled in the river. Optimal labels of ciliates, i.e. sharpdistribution of FMP in cells, were obtained with short incubations(10 min) and low FMP concentrations (1 x 105 mL1). GPTvaried between 30 and 45 min for B. calyciflorus and from 25up to >35 min for rotifers from the river. The ingestionrate of B. calyciflorus fed with T. pyriformis was 3.3 ±0.6 ciliate rot1 h1, i.e. 1.4 ± 0.3 ngCrot1 h1. Metazooplankton species for which theingestion of ciliates could be measured were the rotifers Keratellacochlearis, Euchlanis dilatata and Synchaeta spp. Ingestionrates measured ranged from 0.4 to 12.5 ngC rot1 h1.The method proposed proved to be useful in estimating the predationof microplankton on ciliates in semi- in situ conditions; infurther developments, labelled natural assemblages of ciliatescould be used for in situ incubations with the Haney chamber. 相似文献
9.
Shinnosuke Ohmori Mayumi Kimizu Maiko Sugita Akio Miyao Hirohiko Hirochika Eiji Uchida Yasuo Nagato Hitoshi Yoshida 《The Plant cell》2009,21(10):3008-3025
Floral organ identity and meristem determinacy in plants are controlled by combinations of activities mediated by MADS box genes. AGAMOUS-LIKE6 (AGL6)-like genes are MADS box genes expressed in floral tissues, but their biological functions are mostly unknown. Here, we describe an AGL6-like gene in rice (Oryza sativa), MOSAIC FLORAL ORGANS1 (MFO1/MADS6), that regulates floral organ identity and floral meristem determinacy. In the flower of mfo1 mutants, the identities of palea and lodicule are disturbed, and mosaic organs were observed. Furthermore, the determinacy of the floral meristem was lost, and extra carpels or spikelets developed in mfo1 florets. The expression patterns of floral MADS box genes were disturbed in the mutant florets. Suppression of another rice AGL6-like gene, MADS17, caused no morphological abnormalities in the wild-type background, but it enhanced the phenotype in the mfo1 background, indicating that MADS17 has a minor but redundant function with that of MFO1. Whereas single mutants in either MFO1 or the SEPALLATA-like gene LHS1 showed moderate phenotypes, the mfo1 lhs1 double mutant showed a severe phenotype, including the loss of spikelet meristem determinacy. We propose that rice AGL6-like genes help to control floral organ identity and the establishment and determinacy of the floral meristem redundantly with LHS1. 相似文献
10.
Mass developments of rotifers of the genus Brachionus, and especiallyof B.quadridentatus, occur regularly in the largely hypertrophicchain of shallow waters (boddens) south of theDarss-Zingst peninsula (Southern Baltic). Interest in the autecologyof the species is, therefore, considerable. Various food sourceswere used in laboratory experiments to ascertain the food requirementsof B.quadridentatus, determine its filtration and ingestionrates, and assess its food particle size-selection ability.Growth experiments showed that the chlorophyceans Nannochlorissp. and Chlorella vulgaris possess considerable nutritionalvalue for the species, whereas abundances declined when Microcystisfirma, detritus from Enteromorpha sp. and only bacteria (Pseudomonas),respectively, were provided as food sources. Filtration ratesvaried between 0.02 and 1.73 µl ind.1 h1,and ingestion rates between 121 and 5560 cells ind.1h1, depending on the filtration rate and algal concentration.Investigations into food particle size selection using fluorescentlatex particles revealed that particle size influences foodparticle intake. When particles of different sizes were mixed,the animals showed a preference for the larger particles andingested the smaller ones with a diameter of 12 µmless efficiently. The brackish water species Brachionus plicatiliswas studied besides B.quadridentatus in all experiments. Theformer species proved to be superior both in its range of utilizableparticle sizes and its growth rate. The experiments with laboratorycultures were backed up by studies performed with various rotiferspecies taken from natural populations. 相似文献
11.
12.
13.
Oraguzie NC Iwanami H Soejima J Harada T Hall A 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,108(8):1526-1533
The 1-aminocyclopropane-1-carboxylic acid synthase (ACS) gene is a member of the ACS gene family that is involved in apple (Malus × domestica Borkh.) fruit ripening. Presence of an allele (Md-ACS1-2) of this gene is associated with low internal ethylene concentration in some apple cultivars. In this study, inheritance of Md-ACS1 was determined for 50 apple cultivars/advanced selections and 101 F1 seedlings from five populations. Following this, the softening pattern of apples stored at 20°C for up to 40 days was examined using 35 fruiting cultivars/selections of defined Md-ACS1 status. Md-ACS1 is inherited in a Mendelian fashion and was found to be linked to fruit softening. Maturity season of genotypes also significantly affected fruit softening. Late-season genotypes in the Md-ACS1-2/2 class had the slowest rate of softening, while early-season Md-ACS1-1/1 genotypes had the most rapid softening rate. The implications of these results are discussed in relation to parental selection and breeding for storage ability in apple.Communicated by H. Nybom 相似文献
14.
15.
Seok HY Park HY Park JI Lee YM Lee SY An G Moon YH 《Biochemical and biophysical research communications》2010,401(4):598-604
To investigate ternary MADS protein complexes involved in the regulation of floral organ development in rice, we identified MADS proteins interacting with the class B MADS heterodimers, OsMADS16-OsMADS4 and OsMADS16-OsMADS2, using yeast three-hybrid assay. The class B heterodimers interacted with OsMADS6, 7, 8, 14 and 17, which belong to AP1-like, SEP-like or AGL6-like MADS proteins, generating ternary complexes. The entire region of the K and C domains of OsMADS4 was required for the formation of the OsMADS16-OsMADS4-OsMADS6 and OsMADS16-OsMADS4-OsMADS7 ternary complexes. Analysis results of transgenic plants concomitantly suppressing OsMADS4 and OsMADS6, together with the results of previous studies, suggest that the OsMADS16-OsMADS4-OsMADS6 ternary complex plays an important role in floral development, especially lodicule development. 相似文献
16.
17.
18.
The Genetic Basis of Malathion Resistance in Housefly (Musca domestica L.) Strains From Turkey 总被引:1,自引:0,他引:1
Organophosphate insecticide (parathion/diazinon) resistance in housefly (Musca domestica L.) is associated with the change in carboxylesterase activity. The product of MdE7 gene is probably playing a role in detoxification of xenobiotic esters. In our research, we have isolated, cloned and sequenced the MdE7 gene from five different Turkish housefly strains. High doses of malathion (600 g/fly) were applied in a laboratory environment for one year to Ceyhan1, Ceyhan2, Adana, and Ankara strains while no insecticide treatment was performed in the laboratory to Kirazli strain. Trp251 Ser substitution was found in the product of MdE7 gene in all malathion-resistant and Kirazli stocks. In addition, we checked the malathion carboxylesterase (MCE), percent remaining activities in acetylcholinesterase (AChE), glutathion-S-transferase (GST), and general esterase activities in all five strains used in this study. In comparing with universal standard sensitive control WHO, a high level of MCE and GST activities were observed while lower level of general esterase activities was detected in the tested strains. In addition, a higher percent remaining activities in AChE than WHO susceptible strain were observed in all malathion-resistant strains. 相似文献
19.
Jongmin Nam Yoo Kyung Lee Jung Hyun Oak Gynheung An In Kyu Lee 《Journal of Plant Biology》1999,42(1):81-84
The conserved region of numerous MADS genes in gulfweed (Sargassum fulvellum) was cloned by PCR with degenerate primers. Analysis of seventy individual clones resulted in the identification of nineteen
types of nucleotide sequences. There sequences encode portions of the MADS domain in four distinctive groups. Six clones belong
to the AGAMOUS subfamily, ten to AGL2, and two to AGL12. The remaining one clone is distinctive and appears to be diverged
from an ancestor of the AGL2 and AP1 groups. There were no A or B class MADS genes. These results suggest that, as found in
land plants, MADS genes also play major roles in controlling the development of algae. 相似文献
20.
Plant development going MADS 总被引:10,自引:0,他引:10
Jack T 《Plant molecular biology》2001,46(5):515-520
It has been known for a decade that the plant MADS genesare important regulators of meristem and floral organ identity. The MADS family in Arabidopsis consists of more than 80 members and, until recently, the function of the majority of these genes was unknown. With the enhanced ability to generate loss-of-function mutants and over-expression lines, the function of the MADS gene family members is beginning to be elucidated. Recent progress demonstrates that MADS genes in Arabidopsis are important regulators not only of meristem and floral organ identity but also of flowering timing and cell-type specification in floral organs. 相似文献