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1.
《Biomass》1988,15(3):133-142
Chrysothamnus nauseous (rubber rabbitbrush) is a desert shrub that grows in high density in large populations over a wide range of environmental conditions in the western United States and contains natural rubber that has potential commercial value. Individual plants of two sympatric subspecies (turbinatus and hololeucus) were analyzed to determine the distribution of rubber and resin within the plant. The highest rubber and the lowest resin contents were in the stems near the soil level whereas the highest resin and lowest rubber were in the top of the plants. Negative correlation between rubber and resin from top to bottom of the plants was significant (r2 = −0·64, p = 0·03) for ssp. turbinatus. During the growing season, the highest rubber and lowest resin contents occured during the summer for both subspecies. In contrast the highest resin and lowest rubber contents occured in the spring for both subspecies. Negative correlation between rubber and resin for one year old tissue in ssp. turbinatus was very significant (r2 = −0·76, p = 0·004). Rubber content was highest when soil moisture was lowest and temperatures were highest. Results suggest that rubber and resin contents are under environmental regulation and that it may be possible to influence rubber and resin content in rubber rabbitbrush by using stress treatments.  相似文献   

2.
The genetic differentiation among Turkish populations of the narrow-clawed crayfish was investigated using a partial sequence of cytochrome oxidase subunit I gene (585 bp) of 183 specimens from 17 different crayfish populations. Median joining network and all phylogenetic analyses disclosed a strong haplotype structure with three prominent clades diverged by a range between 20 and 50 mutations and substantial inter-group pairwise sequence divergence (5.19–6.95 %), suggesting the presence of three distinct clades within the Anatolian populations of Astacus leptodactylus. The divergence times among the three clades of Turkish A. leptodactylus are estimated to be 4.96–3.70 Mya using a molecular clock of 1.4 % sequence divergence per million years, pointing to a lower Pliocene separation. The high level of genetic variability (H d  = 95.8 %, π = 4.17 %) and numerous private haplotypes suggest the presence of refugial populations in Anatolia unaffected by Pleistocene habitat restrictions. The pattern of genetic variation among Turkish A. leptodactylus populations, therefore, suggests that the unrevealed intraspecific genetic structure is independent of geographic tendency and congruent with the previously reported geographic distribution and number of subspecies (A. l. leptodactylus and A. l. salinus) of A. leptodactylus.  相似文献   

3.
We examined population differentiation across a substantial portion of the range of the brown pelican (Pelecanus occidentalis) to assess (1) the genetic distinctness of the Galápagos subspecies (P. o. urinator) and (2) genetic differentiation between subspecies that inhabit the coasts of North and Central America (P. o. californicus and P. o. carolinensis). Birds were sampled from coastal California, coastal Florida, and the Galápagos Islands. Using a 957 bp (bp) fragment of the NADH dehydrogenase subunit 2 (ND2) gene, 661 bp of the mitochondrial control region, and eleven microsatellite loci we characterize population genetic differentiation among 158 brown pelicans. The Galápagos subspecies is genetically distinct from the sampled continental subspecies, possessing a unique ND2 haplotype and unique mitochondrial control region haplotypes. Samples from the two continental subspecies all possessed the same ND2 haplotype and shared four mitochondrial control region haplotypes. Bayesian clustering in STRUCTURE placed the Galápagos subspecies in a distinct genetic group with high probability, but could not differentiate the continental subspecies from one another. Estimates of migration rates from BayesAss indicated substantial migration between continental subspecies, but no migration between the Galápagos subspecies and either continental subspecies. There are clearly two Evolutionarily Significant Units within the range of the brown pelican, which warrants conservation attention. Further investigation should determine how the un-sampled subspecies (P. o. murphyi and P. o. occidentalis) fit into the broader picture.  相似文献   

4.

Aims

This work examines Zn accumulation in four Anthyllis vulneraria subspecies supplemented with mineral nitrogen or grown in the presence of their symbiotic bacteria.

Methods

Anthyllis vulneraria subspecies were grown hydroponically in the presence of high levels of ZnSO4. The plants were either grown in symbiosis with one of two non-metallicolous or metallicolous Mesorhizobium inoculants or in the presence of KNO3.

Results

When exposed to 1,000 μM Zn, shoot and root biomass of three out of our four Anthyllis subspecies cultivated with NO3 dropped significantly by about 24–28 %; carpatica, the fourth subspecies, was not affected. Subspecies carpatica Zn tolerance was confirmed when in symbiosis with the metallicolous strain. In the presence of 1,000 μM Zn, the different Anthyllis subspecies concentrated more Zn in their roots than in their shoots and only subsp. carpatica accumulated a significant amount of Zn in its shoots. The most remarkable feature was the drastic decrease in Zn concentration in both roots (up to 2.5–3 fold) and shoots (2.6-fold) of subsp. carpatica exposed to 1,000 μM Zn and nodulated whatever the Mesorhizobium strain used, compared to the N-grown plants.

Conclusions

Our results bring new perspectives as regards phytostabilization, with the potential use of a rhizobium-inoculated leguminous subspecies displaying unusual Zn tolerance.  相似文献   

5.
6.
The ranges of two earthworm subspecies, Eisenia nordenskioldi nordenskioldi (Eisen 1879) and E. n. pallida Malevi 1956, differ in area and partially overlap. E. n. nordenskioldi populates the entire Asian Russia and eastern regions of the Russian Plain, from the lower reaches of the Volga and Don rivers to the Arctic Ocean coasts, while E. n. pallida has not expanded to the Asian permafrost zone and does not occur in European Russia and in the Urals. These subspecies “hold the record” in cold hardiness: the worms and cocoons of the nominotypical subspecies withstand temperatures down to ?34 and ?40°C, and those of E. n. pallida, to ?28 and ?23°C, respectively. Hence, their distribution is independent of subzero temperatures, and their ability to overwinter at any phase of the life cycle makes them also independent of heat supply during the summer period. Differences in geographic range may also be due to biological features of the subspecies. The nominotypical subspecies feeds belongs to the epiendogeic morphoecological type (feeding on the ground surface), whereas E. n. pallida is a true endogeic earthworm. Both subspecies have similar requirements for soil acidity; however, conditions in coarse-humus organomineral horizons of frozen soils appear to be unfavorable for E. n. pallida, which accounts for the absence of this subspecies in the permafrost zone.  相似文献   

7.
We investigated the phylogeography and subspecies classification of the ostrich (Struthio camelus) by assessing patterns of variation in mitochondrial DNA control region (mtDNA-CR) sequence and across fourteen nuclear microsatellite loci. The current consensus taxonomy of S. camelus names five subspecies based on morphology, geographic range, mtDNA restriction fragment length polymorphism and mtDNA-CR sequence analysis: S. c. camelus, S. c. syriacus, S. c. molybdephanes, S. c. massaicus and S. c. australis. We expanded a previous mtDNA dataset from 18 individual mtDNA-CR sequences to 123 sequences, including sequences from all five subspecies. Importantly, these additional sequences included 43 novel sequences of the red-necked ostrich, S. c. camelus, obtained from birds from Niger. Phylogeographic reconstruction of these sequences matches previous results, with three well-supported clades containing S. c. camelus/syriacus, S. c. molybdophanes, and S. c. massaicus/australis, respectively. The 14 microsatellite loci assessed for 119 individuals of four subspecies (all but S. c. syriacus) showed considerable variation, with an average of 13.4 (±2.0) alleles per locus and a mean observed heterozygosity of 55.7 (±5.3)%. These data revealed high levels of variation within most subspecies, and a structure analysis revealed strong separation between each of the four subspecies. The level of divergence across both marker types suggests the consideration of separate species status for S. c. molybdophanes, and perhaps also for S. c. camelus/syriacus. Both the mtDNA-CR and microsatellite analyzes also suggest that there has been no recent hybridization between the subspecies. These findings are of importance for management of the highly endangered red-necked subspecies (S. c. camelus) and may warrant its placement onto the IUCN red list of threatened animals.  相似文献   

8.
9.
为了揭示中国岩羊不同地理种群的遗传差异,探讨岩羊亚种分化的分子机制,采用中国岩羊不同地理种群的细胞色素b(Cyt b)基因的全序列,分析了碱基变异情况、遗传距离以及核苷酸序列差异。用最大似然法和贝叶斯法构建分子系统树并对获得的拓扑结构进行分析。结果发现,西藏亚种与四川亚种Cyt b基因平均序列差异为4.2%(±0.007),处于偶蹄目亚种的序列差异范围内,支持了目前对岩羊西藏亚种的分类地位。四川亚种内部各地理种群之间的遗传距离(0.033±0.0 111)与它们分别到西藏种群的遗传距离(0.042±0.007)差异不显著(t=1.824,P=0.084),说明四川亚种内部各地理种群间已经发生较显著的遗传分化。其中,四川、甘肃和青海种群亲缘关系较近,并与四川亚种内部的其它种群已产生了显著的遗传分化。因此认为四川亚种内部各地理种群的种下分化需要深入研究。  相似文献   

10.
Mediterranean pine forests are often attacked by caterpillars of Thaumetopoea pityocampa (Lep., Thaumetopoidae), one of the most important defoliators in the Mediterranean region causing large economic losses and ecological effects. The needle terpene concentrations and emissions may play a key role in the defense of pines. We studied two subspecies of Pinus sylvestris, nevadensis (an endemic and relict subspecies) and iberica , with different levels of caterpillar attack in Sierra Nevada mountains (Spain). GC–MS analyses showed large total concentrations of terpenes (6 to 39 mg g?1 of dry weight) in the needles of both subspecies under field conditions. Concentrations were 25 % higher in “Non-Attacked Trees” (NATs) of the iberica than in the nevadensis subspecies. The branches of NATs had terpene concentrations 20 % higher than those of “Attacked Branches of attacked trees” (ABs). Within attacked trees, the “Non-Attacked Branches” (NABs) also had terpene concentrations 20 % higher than those of ABs. Mainly α-pinene and germacrene D had higher concentrations in NATs and NABs than in ABs. Some terpenes had higher concentrations in NABs than in NATs, indicating possible systemic reactions. In subsp. nevadensis, the percentage of monoterpenes relative to total terpenes was higher in ABs than in other attack states. The rates of emission in nevadensis (standardized to 30 °C) were ca. three times higher in ABs than in NABs and NATs. These results suggest that the lower terpene concentrations and high percentages of monoterpenes in ABs were produced by a combination of emission losses and terpene induction in response to herbivorous attack.  相似文献   

11.
Low-density groups of Allegheny woodrats (Neotoma floridana magister) confined in a 65-m2 cage exhibited despotic social organization in which one alpha rat killed or wounded all other group members within 14 days in each of five experiments. Five of seven high-density groups, consisting of six to fourteen rats in 9·5-m2 cages, were characterized by dominance hierarchies and high levels of social interaction. Two unisexual groups remained disorganized and all but one rat died in both cases. Allegheny woodrats utilized a different alarm signal and exhibited higher levels of agonistic and sexual interaction compared to similar groups of a california subspecies (N. fuscipes macrotus) which occupies a distinctly different habitat.  相似文献   

12.
New alleles of murine factor B (Bf) protein were demonstrated. When ethylenediaminetetraacetic acid (EDTA)-plasmas from inbred and wild mice were analyzed by isoelectro-focusing (IEF) and immunofixation, murine Bf proteins were visualized as distinct protein bands in all mice tested. Four variants of murine Bf could be demonstrated in a large number of tested mice: Bf 1 (isoelectro-focusing point (P.I.) range of 5.8–6.1) exemplified by B10 and B10.BR, Bf 2 (P.I. range of 5.8–6.0) exemplified by B10.MOL (OHM), Bf 3 (P.I. range of 5.6–5.9) exemplified by B10.MOL (TEN2) and Mus musculus (Mus m.) subspecies Chc, Bf4 (P.I. range of 6.0–6.3) exemplified by Mus m. subspecies Shh. The genetic linkage between S locus and Bf locus was studied with two backcross progenies — [B 10.BR × (B10.BR × Mus m. subspecies Chc)F1] and [B 10.BR × (B10.BR × Mus m. subspecies Shh)F1]. Totally, 256 backcross progenies were typed for Bf type and for Ss type (plasma level of the fourth complement protein regulated by S locus). The results indicated that murine Bf was controlled by a single codominant locus located close to the H-2 complex because no mouse showing recombination between Bf locus and S locus was found.  相似文献   

13.
Native DNA duplexes in fibers exist usually in one of three well-known (A, B and C) forms depending on relative humidity, type of cations and the amount of retained salt. To determine the precise influence of these factors and the effect of base composition, as well as base sequence, on DNA secondary structure, X-ray diffraction methods have been used to study all four synthetic DNA duplexes with repeated dinucleotide sequences, eight of the 12 with repeated trinucleotide sequences and seven analogues in which guanine was replaced with hypoxanthine. The results indicate that there are at least six additional allomorphs denoted by B′, C′, C″, D, E and S.The B′ form (h = 0.329 nm) observed for poly(dA) · poly(dT), poly(dI) · poly(dC) and poly[d(A-I)] · poly[d(C-T)] is a minor variant of the traditional B form (h = 0.338 nm) of native DNA. The two C-like forms C′ for poly[d(A-G-C)] · poly-[d(G-C-T)] and poly[d(G-G-T)] · poly[d(A-C-C)] and C″ for poly[d(A-G)] · poly-[d(C-T)] have, respectively, 91 and 92 symmetries which reflect repetition of trinucleotide and dinucleotide sequences, respectively. Although isocompositional with poly(dA) · poly(dT), the existence of the rather different D form (81) for poly[d(A-T)] · poly[d(A-T)] or for poly[d(A-A-T)] · poly[d(A-T-T)] is a clear demonstration of the sequence effect. The I · C pair generally mimics an A · T pair, but poly[d(I-I-T)] · poly[d(A-C-C)] provides a new (E) form with approximately 152 screw symmetry and with 〈h〉 = 0.325 nm and 〈t〉 = 48 dg per nucleotide. The S form (65) observed for poly[d(G-C)] · poly[d(G-C)] and poly[d(A-C)] · poly[d(G-T)] is an unusual left-handed polydinucleotide helix and is accessible to any alternating purine-pyrimidine sequence. In it the two nucleotides have quite different conformations and involve syn purine and anti pyrimidine nucleosides.  相似文献   

14.
A further quantitative analysis of the localization of the centromere on chromosomes was made using 16,817 individual chromosomes obtained from 723 mammalian species. Centromeric position was expressed quantitatively by the size of short arms as per cent weight (Sw) relative to the X-containing haploid set. When the class interval of Sw was 0·1 instead of the previous 0·2 (Imai, 1975), the frequency distribution of Sw showed an uneven (W-shaped) pattern with two distinct antimodes lying at Sw 0·6 (reconfirmation) and 0·1 (new finding). Two hypotheses, that are not mutually exclusive, are proposed to explain the non-random distribution of centromere position. One is that there are three structurally different short arms consisting of (1) centromere, (2) constitutive heterochromatin (as determined by C-banding), and (3) euchromatin, each arm-type being approximately characterized by the size of short arms (Sw) as Sw < 0·1, 0·1 ? Sw ? 0·6 and Sw > 0·6. The other possibility is concerned with an “orthogenetical” change of chromosome morphologies. When the chromosomes with Sw < 0·1, 0·1 ? Sw ? 0·6 and Sw > 0·6 are denoted as telocentric (T), acrocentric (A), and meta-, submeta- and subtelocentric (M, SM & ST), it was suggested that the chromosome morphologies tend to change orthogenetically (in a statistical sense) from T to M, SM & ST via A-chromosomes by rearrangements such as tandem growth of constitutive heterochromatic, pericentric inversions, and centric fusions.  相似文献   

15.
The defensive secretion of the tenebrionid beetle, Eleodes beameri, is quite unlike the benzoquinone and 1-alkene secretion of other species of Eleodes and Tenebrionidae. Twenty-three compounds were isolated from the secretion by gas-liquid chromatography (GLC) and 13 of these were identified by infrared, nuclear magnetic resonance, ultraviolet, and mass spectroscopy. Identified compounds were: 1-nonene (3·2%), 1-undecene (<0·5%), n-hexanal (15·6%), n-heptanal (0·9%), n-octanal (4·5%), trans-2-hexenal (2·0%), trans-2-heptenal (1·5%), trans-2-nonenal (28·6%), trans-2-decenal (3·4%), n-3-nonanone (0·5%), n-1-nonen-3-one (16·8%), methyl-1,4-benzoquinone (22·0%), and 1-hexanol (<0·5%). 1-Nonen-3-one is unique to E. beameri. A number of minor components remain unidentified. The morphology and ultrastructure of the glands were similar to other species of Eleodes. The gland reservoirs are a pair of strongly bilobed sacs with narrow exit ducts opening between abdominal sternites 7 and 8. There are two types of secretory cell units: Type 1 consisting of cells closely attached to the reservoir intima, with large, central vesicles drained by highly convoluted tubules. Type 2 units are composed of a pair of cells functioning together, the cuticular organelle from the microvilli-filled vesicle of the distal cell (2a) passing through the vesicle of the proximal one (2b) and then draining more or less directly into the reservoir via a cuticular tubule.  相似文献   

16.
Crystals of β-lactamase I from Bacillus cereus 569 are monoclinic, space group C2 with unit cell dimensions a = 143·0 (± 0·5), b = 35·8 (± 0·1), c = 52·7 (± 0·2) A?, β = 97·0 (± 0·1) °, and one molecule of molecular weight about 28,000 per asymmetric unit.  相似文献   

17.
Heat stress elicits the expression of heat shock proteins (HSPs) in honey bee subspecies. These highly conserved proteins have significant role in protecting cells from thermal-induced stresses. Honey bees in subtropical regions face extremely dry and hot environment. The expression of HSPs in the nurses and foragers of indigenous (Apis mellifera jemenitica) and imported European (Apis mellifera ligustica and Apis mellifera carnica) honey bee subspecies after heat shock treatment were compared using SDS-PAGE. Hsp70 and Hsp82 were equally expressed in the nurses of all tested bee subspecies when exposed to 40 °C and 45 °C for 4 h. The forager bees exhibited differential expression of HSPs after heat stress. No HSPs was expressed in the foragers of A. m. jemenitica, and Hsp70 was expressed only in the foragers of A. m. ligustica and A. m. carnica at 40 °C. A prominent diversity in HSPs expression was also exhibited in the foragers at 45 °C with one HSP (Hsp70) in A. m. jemenitica, two HSPs (Hsp40 and Hsp70) in A. m. carnica, and three HSPs (Hsp40, Hsp60 and Hsp70) in A. m. ligustica. No HSPs was expressed in the control nurse and forager bees at any of the tested temperatures. These findings illustrated the differences in HSP expression among nurse and forager bees. It is obvious that the native foragers are more heat tolerant with least HSPs expression than exotic bee races. Further investigations will help to understand the potential role of HSPs in the adaptability, survival, and performance of bee subspecies in harsh climate of the subtropical regions.  相似文献   

18.
The character of the cooperativity between the HOX···OH/SH halogen bond (XB) and the Y―H···(H)OX hydrogen bond (HB) in OH/SH···HOX···HY (X = Cl, Br; Y = F, Cl, Br) complexes has been investigated by means of second-order Møller?Plesset perturbation theory (MP2) calculations and “quantum theory of atoms in molecules” (QTAIM) studies. The geometries of the complexes have been determined from the most negative electrostatic potentials (V S,min) and the most positive electrostatic potentials (V S,max) on the electron density contours of the individual species. The greater the V S,max values of HY, the larger the interaction energies of halogen-bonded HOX···OH/SH in the termolecular complexes, indicating that the ability of cooperative effect of hydrogen bond on halogen bond are determined by V S,max of HY. The interaction energies, binding distances, infrared vibrational frequencies, and electron densities ρ at the BCPs of the hydrogen bonds and halogen bonds prove that there is positive cooperativity between these bonds. The potentiation of hydrogen bonds on halogen bonds is greater than that of halogen bonds on hydrogen bonds. QTAIM studies have shown that the halogen bonds and hydrogen bonds are closed-shell noncovalent interactions, and both have greater electrostatic character in the termolecular species compared with the bimolecular species.
Figure
The character of the cooperativity between the X···O/S halogen bond (XB) and the Y―H···O hydrogen bond (HB) in OH/SH···HOX···HY (X=Cl, Br; Y=F, Cl, Br) complexes has been investigated by means of second-order Møller—Plesset perturbation theory (MP2) calculations and “quantum theory of atoms in molecules” (QTAIM) studies.  相似文献   

19.
The bookK. Richter, Plantae europeae, Vol. 1, 1890, is analyzed from the viewpoint of nomenclature of subspecies names. 264 subspecies names interesting from the standpoint of contemporary taxonomy and nomenclature are selected from the total number of 840 subspecies names for a commented list. Seventeen important cases are dealt with separately in greater detail. Eleven new nomenclatural combinations (two for species, nine for subspecies) are proposed in the Appendix. Types for two generic names (Acorellus Palla andJuncellus C. B. Clarke) are proposed. A new term “parabasionym” is applied for names establishing the priority of infraspecific epithets in the rank in question. The need to respect the newly accepted principle of priority of autonymic subspecies names at proposing new nomenclatural combinations is stressed. Examples ofRichter’s subspecies names having priority, subspecies names with necessary changes in their authorship and names having a possible importance as parabasionyms are enumerated in separate lists.  相似文献   

20.
Numerous termite species have been introduced outside their native ranges by human transport, and some have become invasive. The dampwood termite Zootermopsis nevadensis (Hagen), which is native to western North America, has been introduced to and become established in Kawanishi City, Hyogo Prefecture, Japan. Zootermopsis nevadensis is subdivided into two subspecies based on cuticular hydrocarbon (CHC) phenotypes: Znevadensis nevadensis and Znevadensis nuttingi (Haverty and Thorne). Here, we identified Znevadensis in Japan as hybrids between the two subspecies. Chemical analysis showed the presence of 7,15-dimethylhenicosane and 5,17-dimethylhenicosane in the CHCs of Znevadensis in Japan, corresponding to the CHC phenotype of Znnevadensis. Conversely, all mitochondrial cytochrome c oxidase subunit I sequences of Znevadensis in Japan were identical to sequences from Znnuttingi and hybrids between the two subspecies from a native hybrid zone in California, USA. In addition, phylogenetic analysis showed that Znevadensis in Japan formed a clade with Znnuttingi and hybrids between the two subspecies. Our results show discordance between the chemical and genetic features of Znevadensis in Japan, indicating that individuals of Znevadensis in Japan are hybrids between the two subspecies.  相似文献   

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