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1.
A number of cytokinin analogs containing modifications in the heterocyclic moiety were prepared. These compounds were tested for activity as cytokinins and anticytokinins in the tabacco bioassay and the results were used to determine whether any position(s) of the heterocyclic nucleus of cytokinins may require derivatization as part of an over-all "activation" process. 3-substituted 4-alkylaminopyrazolo [3,4-d]pyrimidines and 4-alkylaminopyrrolo[2,3-d]pyrimidines, for example, have (substituted) carbon rather than nitrogen atoms at positions 3 and 5, respectively (analogous to position 7 in purines) and would be predicted to be metabolically stable at these positions. The finding that these compounds had cytokinin activity suggested that modification at the metabolically stable positions. The finding that these compounds had cytokinin activity suggested that modification at the metabolically stable position, and by extension at position 7 in cytokinin analogues which are purines, is not a prerequisite for the expression of cytokinin activity. Similar consideration of other heterocyclic analogs which have cytokinin activity suggests that the active form of a cytokinin can be the exogenous compound itself. Certain structural analogs of cytokinins were found to inhibit the growth of tobacco callus promoted by 6-(3-methyl-2-butenylamino)purine. These compounds were studied as potential cytokinin antagonists, i.e. having activity analogous to the 7-alkylamino-3-methylpyrazolo[4,3-d]pyrimidines (Hecht, S. M., 2068-2610; Skoog, F., Schmitz, R.Y., Hecht, S.M., and Bock, R. M. (1973) Phytochemistry 12, 25-37). The activity of these compounds is discussed and criteria are proposed to distinguish between those species which are specific anticytokinins and those which otherwise inhibit growth.  相似文献   

2.
In the Ross Sea and Amundsen Sea, four representatives of the genus Paralepidapedon—Paralepidapedon cf. dubium Prudhoe et Bray 1973 sensu Sokolov et Gordeev 2013, P. lepidum (Gaevskaya et Rodyuk 1988), Paralepidapedon sp., and P. variabile sp. n.—were found in demersal fishes Muraenolepis marmorata and Macrourus whitsoni. Paralepidapedon variabile sp. n. is described from Muraenolepis marmorata in the Amundsen Sea. Paralepidapedon variabile sp. n. differs from other species of the genus Paralepidapedon by the position of the anterior border of the vitellarium at the level of the anterior edge of the ventral sucker or genital pore and by the highly variable shape of the testes: from roundish with a smooth edge to sinuate–lobate. Paralepidapedon lepidum was found for the first time in the Antarctic.  相似文献   

3.
Paul Bernier 《Geobios》1978,11(1):141-147
New Dasyclad Alga belonging to the genus MontenegrellaSOKAC & NIKLER, 1973, named M. florifera nov.sp. It is the first species of this genus described before the Cretaceous, in the Portlandian limestones of the southern french Jura mountains.  相似文献   

4.
A bioacoustic analysis is conducted on the defensive sounds produced by 21 species of snakes. The "typical" snake hiss is described as having a broad-frequency span (from roughly 3,000 to 13,000 Hertz) and a dominant frequency near 7,500 Hertz. The "growl" of the king cobra (Ophiophagus hannah) differs from the "typical" snake hiss in consisting solely of frequencies below 2,500 Hertz, with a dominant frequency near 600 Hertz. Structural analysis of the upper respiratory tract of O. hannah suggests that the "growl" is produced by tracheal diverticula functioning as low-frequency resonating chambers. This hypothesis is supported in several ways. An acoustic analysis of a mechanical model of the trachea demonstrates the potential for these diverticula to produce resonance effects. A "growl" also occurs in the mangrove ratsnake (Gonyosoma oxycephalum), a species that also has tracheal diverticula. Flushing the respiratory tract of G. oxycephalum with helium produces a shift of over 1,000 Hertz in the "growl," a shift that is indicative of a resonance effect.  相似文献   

5.
The results of DNA-DNA hybridization and chemotaxonomic studies indicated that the glutamic acid producers Brevibacterium divaricatum DSM 20297T (T=type strain), "Brevibacterium flavum" DSM 20411, "Brevibacterium lactofermentum" DSM 1412 and DSM 20412, Corynebacterium lilium DSM 20137T, and Corynebacterium glutamicum DSM 20300T and DSM 20163 are members of the same species. It is proposed that all of these strains should be classified in the species Corynebacterium glutamicum. Another glutamic acid-producing strain, Corynebacterium callunae DSM 20147T, was not related at the species level to C. glutamicum and should retain its separate species status. A restriction fragment length polymorphism analysis in which oligonucleotides targeted against conserved regions of 16S and 23S rRNA genes were used as hybridizing probes distinguished the individual strains. This method may be a helpful tool for strain identification.  相似文献   

6.
蕲州地区的蕲艾、青蒿、黄花蒿与茵陈的考订   总被引:3,自引:0,他引:3  
林有润  黄奏球   《广西植物》1983,(1):25-31
<正> 蕲州是我国中药材主要产地之一,是湖北省蕲春县的一个集镇,,是我国中医药大师李时珍的家乡。该地区生长的菊科蒿属植物Artemisia Linn。颇多,其中入药的有十余种,并在李时珍《本草纲目》中曾有记载。这里仅对该地区常见入药的蕲艾、青蒿、黄花蒿与茵陈结合《本草纲目》记载的材料作初步的考订。  相似文献   

7.
8.
西双版纳野芭蕉先锋群落优势种群的生态位动态   总被引:11,自引:0,他引:11  
运用Levins(1968)和Pianka(1973)提出的方法研究西双版纳小果野芭蕉先锋群落优势种群的生态位动态特征。结果表明,该群落中生态位宽度值列前五位的种群是:小果野芭蕉(1.6157),木奶果,榕树,接骨木和苎麻;小果野芭蕉的生态位宽度值随着演替进行逐渐增大;群落中降小果野芭焦与其余物种间生态位重叠值普遍较大外,接骨木,木奶果、苎麻和榕树和它种植物之间具有较大幅度的生态位重叠;在三个演替  相似文献   

9.
Two samples of "refusal factor" corn, one stored frozen in Minnesota and one stored dry in Indiana since 1972 or 1973, were analyzed for the presence of Fusarium spp. and Fusarium toxins. Both samples were from corn refused by swine in Indiana from 1972 to 1973. Sample FS 808 (stored in Indiana) contained 20 ppm of deoxynivalenol (20 micrograms/g), 16 ppm of 15-acetyl-deoxynivalenol, 5 ppm of zearalenone, and 0.2 ppm of alpha-zearalenol. Sample FS 362 (stored in Minnesota) contained 3 ppm of deoxynivalenol, 1 ppm of 15-acetyldeoxynivalenol, and 0.3 ppm of zearalenone. The presence of 15-acetyl-deoxynivalenol is significant because it is the first report of it occurring naturally in refusal factor corn, and it may account in part for the refusal that could not be solely attributed to deoxynivalenol.  相似文献   

10.
Hepatotoxic studies of xylidines differ with regard to the animal species and type of isomer. The aim of the present paper is to correlate electronic structure data and physical-chemical properties, studied by the authors during a few previous papers (Sahini & Weinberg, 1973; Sahini, Weinberg & Vasilescu 1976, Weinberg & Sahini, to be published; Weinberg & Sahini, 1980), with the hepatotoxic activity of xylidines. Two possible biochemical mechanisms are advanced by help of correlation equations.  相似文献   

11.
In order to better understand the epidemiology of Human and Animal trypanosomiasis that occur together in sleeping sickness foci, a study of prevalences of animal parasites (Trypanosoma vivax, T. congolense "forest type", and T. simiae) infections was conducted on domestic animals to complete the previous work carried on T. brucei gambiense prevalence using the same animal sample. 875 domestic animals, including 307 pigs, 264 goats, 267 sheep and 37 dogs were sampled in the sleeping sickness foci of Bipindi, Campo, Doumé and Fontem in Cameroon. The polymerase chain reaction (PCR) based method was used to identify these trypanosome species. A total of 237 (27.08%) domestic animals were infected by at least one trypanosome species. The prevalence of T. vivax, T. congolense "forest type" and T. simiae were 20.91%, 11.42% and 0.34% respectively. The prevalences of 7 vivax and T. congolense "forest type" differed significantly between the animal species and between the foci (p < 0.0001); however, these two trypanosomes were found in all animal species as well as in all the foci subjected to the study. The high prevalences of 7 vivax and T congolense "forest type" in Bipindi and Fontem-Center indicate their intense transmission in these foci.  相似文献   

12.
The genomic relatedness between Listeria grayi and Listeria murrayi was reevaluated by using DNA-DNA hybridization, multilocus enzyme electrophoresis, and rRNA restriction fragment length polymorphism techniques. The high levels of similarity observed between the strains of these two species confirmed the data published since 1973 and indicated that they should be considered members of a single species. On grounds of priority, the species should be named L. grayi.  相似文献   

13.
Two monorchiid species are reported from the freckled goatfish, Upeneus tragula Richardson, from Moreton Bay, Queensland, Australia. Specimens of a species new to science were most morphologically similar to species of the genus Timonia Bartoli & Prevot, 1966, but significant differences in the arrangement of the testes (symmetrical vs oblique) and morphology of the terminal organ (bipartite vs unipartite) necessitate the proposal of a new genus; Madhavia n. g. is proposed for M. fellaminutus n. sp. Specimens of the second species are identified as Parachrisomon delicatus (Manter & Pritchard, 1964) Madhavi, 2008, extending its known range from Hawaii to Australia. Complete ITS2 and partial 28S rDNA sequence data were generated for both species and analysed with those for other monorchiids available on GenBank. Phylogenetic analyses of the 28S rDNA dataset showed that both genera are distinct from other sequenced monorchiids, but overall the resolution between genera is poor and more sequence data are required to elucidate relationships within the family. We propose to transfer Timonia stunkardi (Ahmad, 1985) and Timonia vinodae (Ahmad, 1987) to the genus Neotimonia Madhavi, 2008, as Neotimonia stunkardi (Ahmad, 1985) n. comb. and Neotimonia vinodae (Ahmad, 1987) n. comb. Additionally, we were unable to locate any literature on Parachrisomon brotulidorum (Toman, 1973) Madhavi, 2008 and consider this species as nomen nudum.  相似文献   

14.
The African forest dwelling Hemiacridine grasshopper genus Kassongia I. Bolivar, 1908, is revised. Keys are provided to the males of the species and subspecies. Three new species, maculifemur sp.n., rufogeniculata sp.n., subfuscata sp.n., and one subspecies, flavovittata microptera subsp.n., are described.
Labidioloryma gen.n., with type-species Labidioloryma strictoforcepts sp.n. from Malawi, is described and allocated to the Loryma genus-group ( sensu Brown, 1959, 1973).  相似文献   

15.
Imanishi's "mental" (cerebral) view of speciation is presented, in Mizuhata's revision. The key concept here is the "ethological partition" of the species. Members of each species=society (etho-species) share the same mental (brain) software, irrespective of their genetic structure. Cerebral animals perform active programmed selection, not to be confused with passive, non-programmed "natural selection" as in Neo-Darwinism. The program includes mating-choice of peculiar characters, distinct from the Neo-Darwinian sexual selection supposed due to the specific choosy genes. Speciation can occur, as a "partition of species=society", with bifurcation of mate-choosing program in the parent species. A main promoter for this bifurcation is species-specific "passion" for especially significant characters: long necks, ornamental antlers, ocelli feathers, bright nuptial colors etc. The cichlids in Lake Victoria achieved explosive speciation, while retaining their genetic homogeneity completely. Therefore it is illogical to attribute this divergence to extraordinary mutations in "action controlling genes". The origin of species=society (etho-species) can trace along to the Cambrian Period.  相似文献   

16.
gamma-Glutamylcysteine synthetase was purified from rat liver by an improved method involving chromatography on Sepharose-aminohexyl-ATP to a specific activity of about 1600 units/mg, or approximately twice that previously obtained; it is thus the most active preparation of this enzyme thus far isolated. The earlier preparation, which is homogeneous on polyacrylamide gel electrophoresis, exhibits "half of the sites" reactivity in that it binds a maximum of 0.5 mol of the inhibitor L-methionine-S-sulfoximine phosphate per mol of enzyme. In contrast, the present enzyme preparation binds 1 mol of methionine sulfoximine phosphate per mol of enzyme; it also differs from the enzyme obtained earlier in exhibiting much less ATPase activity and less activity in catalyzing ATP-dependent cyclization of glutamate. gamma-Glutamylcysteine synthetase dissociates in sodium dodecyl sulfate into two nonidentical subunits of apparent molecular weights 74,000 and 24,000; after cross-linking with dimethyl-suberimidate, a species having a molecular weight of about 100,000 was found on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. New information has been obtained about the interaction of the enzyme with glutamate analogs; thus, the enzyme is active with such glutamate analogs as beta-glutamate, N-methyl-L-glutamate, and threo-beta-hydroxy-L-glutanate, and it is effectively inhibited by cis-1-amino-1,3-dicarboxycyclonexane, 2-amino-4-phosphonobutyrate, and gamma-methylglutamate.  相似文献   

17.
Mechanisms that mediate limb development are regarded as highly conserved among vertebrates, especially tetrapods. Yet, this assumption is based on the study of relatively few species, and virtually none of those that display any of a large number of specialized life-history or reproductive modes, which might be expected to affect developmental pattern or process. Direct development is an alternative life history found in many anuran amphibians. Many adult features that form after hatching in metamorphic frogs, such as limbs, appear during embryogenesis in direct-developing species. Limb development in the direct-developing frog Eleutherodactylus coqui presents a mosaic of apparently conserved and novel features. The former include the basic sequence and pattern of limb chondrogenesis, which are typical of anurans generally and appear largely unaffected by the gross shift in developmental timing; expression of Distal-less protein (Dlx) in the distal ectoderm; expression of the gene Sonic hedgehog (Shh) in the zone of polarizing activity (ZPA); and the ability of the ZPA to induce supernumerary digits when transplanted to the anterior region of an early host limb bud. Novel features include the absence of a morphologically distinct apical ectodermal ridge, the ability of the limb to continue distal outgrowth and differentiation following removal of the distal ectoderm, and earlier cessation of the inductive ability of the ZPA. Attempts to represent tetrapod limb development as a developmental "module" must allow for this kind of evolutionary variation among species.  相似文献   

18.
Summary We confirm the hypothesis of Low (1973) that many E. coli K 12 strains contain a prophage (the Rac prophage) located a few minutes clockwise of the trp operon on the genetic map. We have used restriction endonucleases and 32P-labelled probes to construct a physical map of this prophage. Some E. coli K 12 strains, including AB1157, have lost the entire prophage, apparently by a specific deletion. This is consistent with prophage excision by site-specific recombination. reverse (rev) phages (Zissler et al., 1971) are recombination proficient derivatives of phage in which the phage recombination functions have been replaced by analogous functions (RecE) derived from the host chromosome (Gottesman et al., 1974; Gillen et al., 1977). Our data support the origin of rev phages by recombination between and the Rac prophage following excision of the Rac prophage from the E. coli chromosome.Important experimental data are included in the Figure legends.  相似文献   

19.
Based on examination of the type material, the following new synonymy is established: A. granarius (L., 1767) = A. tomskianus Balthasar, 1973, syn. n., A. granarius (L., 1767) = A. pecirkai Balthasar, 1932, syn. n.  相似文献   

20.
广西大苗山“打鸟坳”趋光性鸟类调查   总被引:6,自引:1,他引:5  
2000年9月、2001年5月和10月2、002年5月和10月、2003年10月、2005年9月,通过实地调查和访问当地群众的方法,对广西大苗山“打鸟坳”的趋光性鸟类进行了调查,在大苗山发现了规模较大的“打鸟坳”共5个,并记录趋光性鸟类58种,隶属于10目14科。其中留鸟16种,夏候鸟15种,冬候鸟17种,旅鸟10种。趋光性鸟类主要以鹭科(Ardeidae)、三趾鹑科(Turnicidae)、秧鸡科(Rallidae)等涉禽为主。鹭科鸟类数量较多的有白鹭(Egretta garzetta)和池鹭(Ardeola bacchus);三趾鹑科数量最多的为黄脚三趾鹑(Turnix tanki);秧鸡科以白胸苦恶鸟(Amaurornis phoenicurus)最多。文中还对“打鸟坳”的形成以及部分留鸟被捕获的现象进行了讨论,并对大苗山“打鸟坳”鸟类的保护提出了建议。  相似文献   

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