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1.
The 9,10-dihydrophenanthrene phenolic compound juncusol, from the marsh plant Juncusroemerianus, has been shown to be inhibitory to four species of naturally occurring Bacillus and to two ATCC species Bacillussubtilis and Staphylococcusaureus. Juncusol may regulate populations of bacillus bacteria in the marsh and has potential as an antimicrobial agent particularly to gram positive microorganisms.  相似文献   

2.
The chlorophyll composition and Hill activity of the leaf, developing seed parts and pod have been studied in three species of legumes, Lathyrus latifolius, Pisum sativum and Vicia faba. The studies indicate that in all the species, the level of chlorophyll, on mg/g fresh weight basis, is maximum in the leaf. However, Hill activity studies show that the cotyledonary chloroplasts in all the cases have a higher Hill activity than the leaf chloroplasts. Thus, the Hill activities of the cotyledonary chloroplasts are 340% of the leaf chloroplasts in Lathyruslatifolius, 144% of the leaf chloroplasts in Pisumsativum and 200% of the leaf chloroplasts in Viciafaba.  相似文献   

3.
Twenty-one individuals each of the species great tits (Parus major), blue tits (Parus caeruleus), marsh tits (Parus palustris), blackbirds (Turdus merula), songthrushes (Turdus philomelos), tree sparrows (Passer montanus) and house sparrows (Passer domesticus) were conditioned to a keypeck response by means of food reinforcement. The site where the reward was given was then changed. The number of reinforcements were then counted until the keypeck response followed immediately (within 10 seconds) on three successive occasions, and a comparison was made between species. Of the species studied the blackbird needed significantly fewer instances of reinforcement in order to re-establish an immediate keypeck response. A significant difference was also seen between the performance of the great tit and marsh tit, as well as between the blue tit and the marsh tit. No significant difference was found between the performance of the house sparrow and the tree sparrow.  相似文献   

4.
Extracts of 40 hr Artemiasalina nauplii can convert a heavy form of elongation factor 1 (EF-1H) to a light species (EF-1L). The data indicate that a protease in the extracts is responsible for this reaction, and these findings may explain the observation that extracts from Artemiasalina nauplii have only EF-1L whereas before hatching of the Artemiasalina embryos EF-1H is the predominant species (Slobin and M?ller [1975] Nature 258, 452–454).  相似文献   

5.
The squirrel monkey (Saimiri,sciureus), a New World primate, contains multiple copies of endogenous type D retroviral gene sequences in the cellular DNA of all its tissues. Gene sequences partially homologous to these type D virus genes are also found in the cellular DNA of normal tissues of the New World carnivore, the skunk (Mephitis,mephitis and Spilogale,putorius). We there-fore conclude that this class of viruses has, under natural conditions, been transmitted between the germ lines of these evolutionarily distant species. The example of interspecies transmission described here is the first that has been described among New World species and also the first that has been demonstrated for retroviruses other than type C viruses.  相似文献   

6.
Primary leaves of 7-to-9 day-old etiolated bean seedlings contain a species of protochlorophyllide which is not transformed to chlorophyllide by light; this pigment species exhibits an absorption peak at 631nm invivo at ?196° and a fluorescence emission peak at 639nm invivo at room temperature. Heat-treatment of etiolated leaves converts the phototransformable protochlorophyllide holochrome to a pigment species with invivo absorption and fluorescence peaks identical to those of endogenous nontransformable protochlorophyllide. Administration of δ-amino-levulinic acid to etiolated leaves causes the synthesis of non-transformable protochlorophyllide with an absorption peak also at 631nm invivo at ?196° but with a fluorescence emission peak at 643nm invivo at room temperature. Heat-treatment of such leaves does not affect the position of these bands. The results indicate that protochlorophyllide which is derived from exogenous δ-amino-levulinic acid is in a physically different state from other forms of protochlorophyllide in the leaf.  相似文献   

7.
8.
Cytoplasmic factors in the gonads of Culex pipiens complex mosquitoes   总被引:1,自引:0,他引:1  
R J Irving-Bell 《Life sciences》1974,14(6):1149-1151
Electron microscopic examination of the gonads of six species of the Culex pipiens complex revealed rickettsia-like, intracellular symbionts in C.pipiens, C.molestus, C.pallens and C.fatigans.1 In the two endemic Australian members, C.aC.globocoxitus, no rickettsia-like symbionts were found, but virus-like particles were seen in the cytoplasm of the ovaries and certain associated tissues.  相似文献   

9.
Coccidioidesimmits has been isolated from the guano of bats obtained beneath bat roosting places deep within deserted mine tunnels. Certain species of bats have been demonstrated to be susceptible to experimental infection by C.immitis. There is, however, a difference in the laboratory susceptibility between the species studied (Antrozouspallidus and Macrotuscalifornicus). Antrozouspallidus requires 8 times more arthrospores (400 as compared to 50) than does Macrotuscalifornicus to produce a defineable infection. Our cultures for C.immitis in the tissue of Antrozous produced colonies of the bacterium Serratiamarcescens. Because these tissues were handled under sterile conditions the presence of this red pigment (prodigiosin) producing bacterium was thought not the result of contamination. Prodigiosin suggests a possible mechanism for the apparent greatly reduced susceptibility to C. immitis found in the laboratory population of Antrozous. Skin and serological tests on bats were negative as were cultures of guano from experimentally infected bats and mice. It is speculated that infected dying bats that fall to the floor beneath their roosting sites may contaminate the guano. We of course realize that other animals (we have found Neotoma and Bassariscus rarely in these tunnels) may have tracked the fungus into these deep tunnel sites.  相似文献   

10.
Chemically formylated Met-tRNAmMet and Met-tRNAfMet species from E.coli and yeast were tested for their capacity to serve as chain-initiators in a cell-free system from E.coli. In the presence of R 17 mRNA, initiation factors and E.coli ribosomes, all four Met-tRNAs could form functional initiation complexes as measured by ribosomal binding kinetics, fMet-puromycin formation and synthesis of a dipeptide fMet-Ala. Unformylated Met-tRNAfMet from E.coli displayed significantly less activity as a peptide chain-initiator than the formylated Met-tRNAmMet species from E.coli and yeast. Although the latter tRNAs were less effective initiators than the “physiological” initiator tRNAs, the data seem to indicate that a blocked α-amino group represents the major token of identification by which Met-tRNA is admitted to function in E.coli peptide chain initiation.  相似文献   

11.
Rabbit peritoneal neutrophils incorporated [14C]arachidonic acid into seven molecular species of choline-containing phosphoglycerides. These 2-[14C]arachidonoyl species differed with respect to the alkyl ether or acyl residue bound at the sn-1 position; four of the seven were ether-linked. Stimulation with calcium ionophore A23187 induced a proportionate release of arachidonate from all seven molecular species: 40% of the released arachidonate came from alkyl ether species. Thus, 1-O-alkyl-2-arachidonoyl-sn-glycero-3-phosphocholine (GPC) is a significant source of metabolizable arachidonic acid. Since 1-O-alkyl-2-lyso-GPC is the metabolic precussor of platelet activating factor, these results further interrelate pathways forming arachidonate metabolites and platelet activating factor; they also supply a rationale for the observation that both classes of stimuli form concomitantly during cell activation.  相似文献   

12.
The goldsinny, Ctenolabrusrupestris, on the Swedish west-coast has been shown to be a facultative cleaner with the ballan wrasse, Labrusberggylta, as the cleanee. Twenty-four cleanings were observed during 1975 to 1981. The cleaning pattern of the symbiosis is described and the low rate of cleaners within the species is discussed.  相似文献   

13.
The cleavage of the kDNA minicircles of Trypanosoma equiperdum by the restriction endonucleases Hinf I, Bgl II, Mbo I, Tag I and Mbo II revealed that this kDNA is homogeneous in base sequence. This is in contrast with the kDNA of minicircles of the other species of trypanosomes so far studied. The 10 cleavage sites, obtained with these endonucleases, were ordered and a restriction cleavage map of the minicircles was thus drawn.  相似文献   

14.
P Licht  S W Farmer  H Papkoff 《Life sciences》1975,17(7):1049-1054
Gonadotropic hormones were fractionated from pituitaries of the urodele amphibian Ambystomatigrinum (tiger salamander) by methods previously employed to separate these hormones in other species of tetrapod vertebrates. These procedures yielded two distinct fractions that resembled the FSH and LH from other species in regard to their biological profiles in several nonmammalian bioassays and by their chromatographic behavior. The Ambystoma-FSH was free of LH activity (< 0.1%). The major Ambystoma-LH was highly potent in ovulation assays for LH; it also had a high activity in the Anolis lizard assay, but it is not clear whether this reflects high intrinsic activity or incomplete separation of FSH.In vitro studies with these and other (frog, turtle, mammalian) gonadotropins indicate that the induction of ovulation in Ambystoma, as in anurans, is highly specific for LH, independent of the source of the gonadotropins. These data support the view that two separate gonadotropins existed early in tetrapod evolution.  相似文献   

15.
Solid phase peptide synthesis of alpha-factor, a yeast mating pheromone.   总被引:5,自引:0,他引:5  
Based on analysis of highly purified preparations of natural α-factor and on the sequence recently reported by others, oligopeptides of the following structures were chemically synthesized by the solid phase method of Merrifield: N-Trp-His-Trp-Leu-Lys-Pro-Gly-G1N-Pro-Met-Tyr-C N-His-Trp-Leu-Lys-Pro-Gly-G1N-Pro-Met-Tyr-C Both synthetic species arrested a cells in G1, inhibited their DNA synthesis, caused them to elongate markedly, and induced an increase in their adhesivity toward α cells. Neither synthetic material caused any of these effects in α cells or in aα diploids.  相似文献   

16.
The preen gland secretions from eight species of the genera Acrocephalus and Sylvia (Sylviidae, Passeriformes) mainly consist of monoester waxes. The fatty acids and alcohols are methyl-substituted at even numbered positions only. One of the methyl groups of the fatty acids is always located in the 2-position. Two patterns of methyl substitution are found for the alkanols: 2-mono-, 2,6-di-, and 2,6,x-trimethyl on the one hand, and 4-mono-, 4,8-di-, and 4,8,y-trimethyl on the other. There is, however, no doubt in the uniformity of the family Sylviidae from the chemotaxonomical point of view; the waxes of the species investigated can be arranged in a gradual succession of substitution patterns. The monoester waxes of Sylviidae are similar to those found for the closely related family Turdidae.  相似文献   

17.
U E Brady 《Life sciences》1973,13(3):227-235
Cis-9-tetradecen-l-ol acetate was isolated from both extracts of female abdominal tips and of filter paper exposed to female Cadracautella (Walker). It is the second sex stimulant isolated from this species and, in stimulatory bioassays, it is ca. 1/100, 000 as active as the stimulant isolated previously, cis-9, trans-12-tetradecadien-l-ol acetate. According to attractancy tests, the natural sex pheromone system of complex contains other components in addition to these 2 stimulants.  相似文献   

18.
Behavioral comparisons of the stereoisomers of tetrahydrocannabinols   总被引:1,自引:0,他引:1  
The potencies of (?)-trans9-THC, (+)-trans9-THC, (+)-cis9-THC, (?)-trans8-THC and (+)-trans8-THC were compared in several different species. (?)-trans9-THC was 100 times more potent than (+)-trans9-THC in depressing schedule-controlled responding in monkeys. The (+)-trans isomers were less effective than their corresponding (?)-trans isomers in the dog static-ataxia test, but potency ratios could not be determined due to a lack of dose-responsiveness of the (+)-trans isomers. However, it appeared that their potency differed by at least ten fold. The potency of (+)-cis9-THC in the dog static-ataxia test was comparable to that of (+)-trans9-THC. The hypothermia in mice produced by the (?) isomers of trans9-THC and trans8-THC were 9.1 and 30.4 times greater than that produced by their respective (+)-isomers. Also, the potency ratio of the (+)- and (?)-trans9-THC was 5.6 as measured by depression of spontaneous activity in mice. The magnitude of the potency ratios of the THC stereo-isomers is dependent upon the species and the pharmacological test used.  相似文献   

19.
Affinity chromatographic systems are described for the purification of neutral metalloendopeptidases on columns of acetyl-D-phenylalanine or succinyl-D-leucine covalently linked to Sepharose by spacers of various lengths. The neutral proteases of B. subtilis are separated in a single chromatographic procedure from all other proteins of the culture filtrates and subfractionated into two active species. An analogous chromatographic system is effective in the purification of thermolysin of B. thermoproteolyticus.  相似文献   

20.
A survey of flavonoids in the leaves of 81 species of the Zingiberales showed that, while most of the major classes of flavonoid are represented in the order, only two families, the Zingiberaceae and Marantaceae are rich in these constituents. In the Musaceae (in 9 species), Strelitziaceae (in 8 species) and Cannaceae (1 of 2 species) flavonol glycosides were detected in small amount and in the Lowiaceae no flavonoids were fully identified. In the Zingiberaceae kaempferol (in 22%), quercetin (72%) and proanthocyanidins (71%) are distributed throughout the family. The two subfamilies of the Zingiberaceae may be distinguished by the presence of myricetin (in 26%), isorhamnetin (10%) and syringetin (3%) in the Zingiberoideae and of flavone C-glycosides (in 86% of taxa) in the Costoideae. A number of genera have distinctive flavonol profiles: e.g. Hedychium species have myricetin and quercetin. Roscoea species isorhamnetin and quercetin and Alpinia species kaempferol and quercetin glycosides. A new glycoside, syringetin 3-rhamnoside was identified in Hedychium stenopetalum. In the Zingiberoideae flavonols were found in glycosidic combination with glucuronic acid, rhamnose and glucose but glucuronides were not detected in the Costoideae or elsewhere in the Zingiberales. The Marantaceae is chemically the most diverse group and may be distinguished from other members of the Zingiberales by the occurrence of both flavone O- and C-glycosides and the absence of kaempferol and isorhamnetin glycosides. The distribution of flavonoid constituents within the Marantaceae does not closely follow the existing tribai or generic limits. Flavonols (in 50% of species). flavones (20%) and flavone C-glycosides (40%) are found with similar frequency in the two tribes and in the genera Calathea and Maranta both flavone and flavonol glycosides occur. Apigenin- and luteolin-7-sulphates and luteolin-7,3′-disulphate were identified in Maranta bicolor and M. leuconeura var. kerchoveana and several flavone C-glycosides sulphates in Stromanthe sanguinea. Anthocyanins were identified in those species with pigmented leaves or stems and a common pattern based on cyanidin-and delphinidin-3-rutinosides was observed throughout the group. Finally the possible relationship of the Zingiberales to the Commelinales, Liliales, Bromeliales and Fluviales is discussed.  相似文献   

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