DNA sequences of both 5′ and 3′ regions of the plastid ndhF gene were generated in order to study the position of Patrinia and Nardostachys, to check the potential paraphyletic nature of Patrinieae, and to evaluate the possible link between the tribe and Linnaeaceae.
Parsimony analysis showed very strong support for Patrinia as sister to all members of Valerianaceae (including Nardostachys) and indicated the paraphyletic nature of the tribe Patrinieae. Additionally, trees were constructed from available rbcL data separately and supplemented with ndhF sequences. Topologies of these combined cladograms are in agreement with the ndhF phylogeny, suggesting that the traditionally circumscribed Patrinieae can no longer be recognized but must be considered
as part of a basal grade in Valerianaceae. Parsimony analysis based on a morphological data set supported a monophyletic Patrinieae;
combination with the molecular data showed a paraphyletic Patrinieae. Furthermore, the possible link between Patrinieae and
Linnaeaceae is evaluated.
Received July 12, 2001 Accepted February 25, 2002 相似文献
Although numerous people grow up speaking more than one language, the impact of bilingualism on brain developing neuroanatomy is still poorly understood. This study aimed to determine whether the changes in the mean fractional-anisotropy (MFA) of language pathways are different between bilingual and monolingual children. Simultaneous-bilinguals, sequential-bilinguals and monolingual, male and female 10–13 years old children participated in this longitudinal study over a period of two years. We used diffusion tensor tractography to obtain mean fractional-anisotropy values of four language related pathways and one control bundle: 1-left-inferior-occipitofrontal fasciculus/lIFOF, 2-left-arcuate fasciculus/lAF/lSLF, 3-bundle arising from the anterior part of corpus-callosum and projecting to orbital lobe/AC-OL, 4-fibres emerging from anterior-midbody of corpus-callosum (CC) to motor cortices/AMB-PMC, 5- right-inferior-occipitofrontal fasciculus rIFOF as the control pathway unrelated to language. These values and their rate of change were compared between 3 groups. FA-values did not change significantly over two years for lAF/lSLF and AC-OL. Sequential-bilinguals had the highest degree of change in the MFA value of lIFOF, and AMB-PMC did not present significant group differences. The comparison of MFA of lIFOF yielded a significantly higher FA-value in simultaneous bilinguals compared to monolinguals. These findings acknowledge the existing difference of the development of the semantic processing specific pathway between children with different semantic processing procedure. These also support the hypothesis that age of second language acquisition affects the maturation and myelination of some language specific white-matter pathways. 相似文献
Cell-mediated immunity is important in maintaining the virus-host equilibrium in persistent human cytomegalovirus (HCMV) infection. The HCMV 72-kDa major immediate early 1 protein (IE1) is a target for CD8+ cytotoxic T cells in humans, as is the equivalent 89-kDa protein in mouse. Less is known about responses against this protein by CD4+ T cells, which may be important as direct effector cells or helper cells for antibody and CD8+ responses. Proliferative-T-cell responses to HCMV IE1 were studied in normal seropositive subjects. Peripheral blood mononuclear cells from 85% of seropositive subjects proliferated in response to HCMV from infected fibroblasts, and of these, 73% responded to recombinant baculovirus IE1. Responding cells were predominantly CD3+ CD4+. IE1 antigen preparations, including baculovirus recombinant protein, transfected rat cell nuclei, and synthetic peptides, induced IE1-specific T-cell lines which cross-reacted between the preparations. The fine specificity of these IE1-specific T-cell lines was studied by using overlapping synthetic peptides encompassing the entire sequence of the IE1 protein. The regions of the IE1 molecule recognized were identified and these varied between individuals, possibly reflecting differences in major histocompatibility complex (MHC) class II haplotype. In one subject, the peptide specificities of proliferative and MHC class I-restricted cytotoxic determinants on IE1 were spatially distinct. Thus, no single immunodominant T-cell determinant within HCMV IE1 was identified, suggesting that multiple peptides or a region of the 72-kDa IE1 protein would be required to induce specific T-cell responses in humans. 相似文献
More than 40 mostly minor Palaeozoic oolitic ironstones (OI) accumulated on low-latitude cratonic North America, almost entirely in USA. A few Middle Cambrian OI, among the oldest anywhere, were deposited on the western cratonic shelf of USA. Widely scattered Late Cambrian ones developed on the southwestern, southeastern and northeastern flanks of the Transcontinental Arch. Middle Ordovician OI were deposited on the cratonic interior and on the southern and southeastern cratonic margins. In latest Ordovician time Neda OI spread across north-central USA east of the Arch and south of the Laurentian upland. Minor ones developed in the southern part of the Taconian foreland basin after major orogeny. Early and Middle Silurian Clinton OI flourished throughout the foreland basin in eastern USA, producing the largest OI deposit on the North American craton. Minor early Late Silurian OI accumulated in the central part of the basin. Middle and Late Devonian OI in the Acadian foreland basin in northeastern cratonic USA developed progressively westward of the encroaching Catskill delta. An isolated Middle Devonian one accumulated in southwestern cratonic USA, and latest Devonian ones in north-central USA east of the Arch.
During this Palaeozoic episode sites of OI deposition shifted eastward across the craton. Most of the OI were deposited during a hiatus in normal sedimentation, accumulating in the upper part of shoaling-upward sequences. Some early Palaeozoic ones occur in glauconitic siliciclastic-carbonate facies and contain mostly spherical hematitic ooids. These suggest derivation from iron-rich soils developed on glauconitic deposits. OI in wholly siliciclastic facies, containing distorted chamositic ooids with cores of mud peloids, were common in later Palaeozoic time. These OI, like many other Phanerozoic ones, suggest a synsedimentary to early diagenetic origin. 相似文献
Corythalia canosa from Florida is an unusual salticid because it is known to eat ants. This species' specialized behaviour for catching ants is described in detail for the first time and compared to its behaviour for catching other insects. Pystira orbiculata from Queensland is shown to be another ant-eating salticid, although its behaviour for catching ants seems less specialized than that of C. canosa. Three different types of tests of prey preference were carried out. In each type of test C. canosa and P. orbiculata took ants in preference to other insects. Another species of salticid, Trite planiceps from New Zealand, failed to eat ants in these tests, although T. planiceps often attacked then released the ants. Corythalia canosa's and P. orbiculata's preference for ants, and their prey-specific predatory behaviour for catching ants, are shown not to depend on prior experience with ants. 相似文献