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Brazil's Movimento de Trabalhadores Sem Teto (MTST, Homeless Workers' Movement) has grown dramatically in recent years. This growth was partly provided for by the use of a large government housing programme, Minha Casa Minha Vida (MCMV, My House My Life), which allowed the MTST to construct housing for its members and swell its ranks with thousands of new members. Yet some have argued that the MCMV programme used by the MTST may compromise the autonomy of civil society organisations. This article, by contrast, argues that while the MCMV programme encouraged bureaucratic practices, it also helped to promote the cultural politics of the MTST. [ABSTRACT FROM AUTHOR]

The pseudanthial inflorescences of the sunflower family, Asteraceae, mimic a solitary flower but are composed of multiple flowers. Our studies in Gerbera hybrida indicate functional diversification for SEPALLATA ( SEP)-like MADS box genes that often function redundantly in other core eudicots., We conducted phylogenetic and expression analysis for eight SEP-like GERBERA REGULATOR OF CAPITULUM DEVELOPMENT ( GRCD) genes, including previously unstudied gene family members. Transgenic gerbera plants were used to infer gene functions., Adding to the previously identified stamen and carpel functions for GRCD1 and GRCD2, two partially redundant genes, GRCD4 and GRCD5, were found to be indispensable for petal development. Stepwise conversion of floral organs into leaves in the most severe RNA interference lines suggest redundant and additive GRCD activities in organ identity regulation. We show conserved and redundant functions for several GRCD genes in regulation of flower meristem maintenance, while functional diversification for three SEP1/2/4 clade genes in regulation of inflorescence meristem patterning was observed., GRCD genes show both specialized and pleiotropic functions contributing to organ differentiation and flower meristem fate, and uniquely, to patterning of the inflorescence meristem. Altogether, we provide an example of how plant reproductive evolution has used conserved genetic modules for regulating the elaborate inflorescence architecture in Asteraceae. [ABSTRACT FROM AUTHOR]

The complex inflorescences (capitula) of Asteraceae consist of different types of flowers. In Gerbera hybrida (gerbera), the peripheral ray flowers are bilaterally symmetrical and lack functional stamens while the central disc flowers are more radially symmetrical and hermaphroditic. Proteins of the CYC2 subclade of the CYC/ TB1-like TCP domain transcription factors have been recruited several times independently for parallel evolution of bilaterally symmetrical flowers in various angiosperm plant lineages, and have also been shown to regulate flower-type identity in Asteraceae. The CYC2 subclade genes in gerbera show largely overlapping gene expression patterns. At the level of single flowers, their expression domain in petals shows a spatial shift from the dorsal pattern known so far in species with bilaterally symmetrical flowers, suggesting that this change in expression may have evolved after the origin of Asteraceae. Functional analysis indicates that Gh CYC2, Gh CYC3 and Gh CYC4 mediate positional information at the proximal-distal axis of the inflorescence, leading to differentiation of ray flowers, but that they also regulate ray flower petal growth by affecting cell proliferation until the final size and shape of the petals is reached. Moreover, our data show functional diversification for the Gh CYC5 gene. Ectopic activation of Gh CYC5 increases flower density in the inflorescence, suggesting that Gh CYC5 may promote the flower initiation rate during expansion of the capitulum. Our data thus indicate that modification of the ancestral network of TCP factors has, through gene duplications, led to the establishment of new expression domains and to functional diversification. [ABSTRACT FROM AUTHOR]

Chalcone synthase ( CHS) is the key enzyme in the first committed step of the flavonoid biosynthetic pathway and catalyzes the stepwise condensation of 4-coumaroyl-CoA and malonyl-CoA to naringenin chalcone. In plants, CHS is often encoded by a small family of genes that are temporally and spatially regulated. Our earlier studies have shown that GCHS4 is highly activated by ectopic expression of an MYB-type regulator GMYB10 in gerbera ( Gerbera hybrida)., The tissue- and development-specific expression patterns of three gerbera CHS genes were examined. Virus-induced gene silencing ( VIGS) was used to knock down GCHS1 and GCHS4 separately in gerbera inflorescences., Our data show that GCHS4 is the only CHS encoding gene that is expressed in the cyanidin-pigmented vegetative tissues of gerbera cv Terraregina. GCHS3 expression is pronounced in the pappus bristles of the flowers. Expression of both GCHS1 and GCHS4 is high in the epidermal cells of gerbera petals, but only GCHS1 is contributing to flavonoid biosynthesis., Gerbera contains a family of three CHS encoding genes showing different spatial and temporal regulation. GCHS4 expression in gerbera petals is regulated post-transcriptionally, at the level of either translation elongation or protein stability. [ABSTRACT FROM AUTHOR]

Compact, but relatively accurate wavefunctions for the ground state of the Li atom were obtained through the use of a limited basis of exponentially correlated functions with optimized nonlinear parameters. In contrast to our earlier work, the basis contains pre-exponential factors that improve the rate of convergence of the basis-set expansion. The matrix elements needed in the present work were evaluated analytically using recursive methods reported recently by one of us; a check on the programming was provided by comparison with numerical evaluations carried out by Turbiner and Guevara. The rate of convergence of the expansion is compared with those of Hylleraas-basis computations, and a comparison is also made with exponentially correlated studies of He-like systems. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [ABSTRACT FROM AUTHOR]

Parsimony-based phylogenetic analyses of the neotropical tribe Helieae (Gentianaceae) are presented, including 22 of the 23 genera and 60 species. This study is based on data from morphology, palynology, and seed micromorphology (127 structural characters), and DNA sequences (matK, trnL intron, ITS). Phylogenetic reconstructions based on ITS and morphology provided the greatest resolution, morphological data further helping to tentatively place several taxa for which DNA was not available (Celianiha, Lagenanthus, Rogersonanthus, Roraimaea, Senaea, Sipapoantha, Zonan thus). Celiantha, Prepusa and Senaea together appear as the sister clade to the rest of Helieae. The remainder of Helieae is largely divided into two large subclades, the Macrocarpaea subclade and the Symbolanthus subclade. The first subclade includes Macrocarpaea, sister to Chorisepalum, Tachia, and Zonanthus. Iribachia and Neblinantha are placed as sisters to the Symbolanthus subclade, which includes Aripuana, Calolisianthus, Chelonanthus, Helia, Lagenanthus, Lehmanniella, Purdieanthus, Rogersonanthus, Roraimaea, Sipapoantha, and Symbolanthus. Generic-level polyphyly is detected in Chelonanthus and Iribachia. Evolution of morphological characters is discussed, and new pollen and seed characters are evaluated for the first time in a combined morphological-molecular phylogenetic analysis. [ABSTRACT FROM AUTHOR]

Polyploidy has long been recognized as a major force in angiosperm evolution. Recent genomic investigations not only indicate that polyploidy is ubiquitous among angiosperms, but also suggest several ancient genome-doubling events. These include ancient whole genome duplication (WGD) events in basal angiosperm lineages, as well as a proposed paleohexaploid event that may have occurred close to the eudicot divergence. However, there is currently no evidence for WGD in Amborella, the putative sister species to other extant angiosperms. The question is no longer "What proportion of angiosperms are polyploid?", but "How many episodes of polyploidy characterize any given lineage?" New algorithms provide promise that ancestral genomes can be reconstructed for deep divergences (e.g., it may be possible to reconstruct the ancestral eudicot or even the ancestral angiosperm genome). Comparisons of diversification rates suggest that genome doubling may have led to a dramatic increase in species richness in several angiosperm lineages, including Poaceae, Solanaceae, Fabaceae, and Brassicaceae. However, additional genomic studies are needed to pinpoint the exact phylogenetic placement of the ancient polyploidy events within these lineages and to determine when novel genes resulting from polyploidy have enabled adaptive radiations. [ABSTRACT FROM AUTHOR]

Collisions between Xe@C60 and sheets of graphite of various dimensions were simulated. A Tersoff many-body potential modeled the interactions between carbon atoms and a Lennard-Jones potential simulated the xenon-carbon interactions. The simulations were compared to experiment and with simulations which implemented other potentials. The results indicate that a relatively small graphite film can be an accurate approximation for a nearly infinite sheet of graphite. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [ABSTRACT FROM AUTHOR]

The five mint genera Brazoria, Macbridea, Physostegia, Synandra and Warnockia (Lamioideae: Lamiaceae) are all North American endemics. Together with the monotypic European genus Melittis and the Asian genus Chelonopsis, these taxa have been classified as subtribe Melittidinae. Previous morphological studies have failed to uncover synapomorphic characters for this group. We sequenced the plastid trnL-trnF region and trnS-trnG spacer and the nuclear ribosomal 5S non-transcribed spacer ( 5S-NTS) to assess phylogenetic relationships within Melittidinae. Standard parsimony and direct optimization (POY) analyses show Melittis, the type genus of the subtribe, as sister to Stachys. Thus, the monophyly of subtribe Melittidinae is not supported either by molecular or morphological data. However, the North American endemics form a monophyletic group that can be recognized as the recircumscribed tribe Synandreae . The molecular relationships among these genera are corroborated by both morphological and cytological data. The expected close relationship between the south-central endemics Warnockia and Brazoria and their sister relationship to the widespread genus Physostegia is confirmed. Nevertheless, most of the North American endemics are restricted to the south-east of the continent. Dispersal westwards and northwards is correlated with an increase in chromosome numbers. No specific Eurasian origin (i.e., transatlantic or transpacific) can be determined, but Synandreae are clearly distinct from the large Stachys clade, and therefore represent a separate migration into North America. © The Willi Hennig Society 2007. [ABSTRACT FROM AUTHOR]

The article explores the botanical significance of avocado (Persea americana), one of the major fruit crops worldwide. The authors present summaries of existing genetic and genomic resources as well as molecular research avenues for this fruit crop. They also discuss the possibility of using avocado as a model for functional genetics in basal angiosperms and other related genomics studies.

Classical molecular dynamics simulations were run for noble gas atoms confined within a buckminsterfullerene cage. The simulations indicated that all the endohedral complexes X@C60 (X = He, Ne, Ar, Kr, Xe) were stable relative to C60 + X, with the Ar complex being the most stable. Except for the He complex, the minimum-energy configuration was with the endoatom at the geometric center of the cage. The minimum-energy position of the He atom in He@C60 was off-center in a high-symmetry direction, but the energy lowering relative to a centered He atom was found to be small relative to the zero-point energy of the He atom within the cage. The simulations were checked by comparison of static energy computations with the fullerene fixed in its equilibrium geometry as determined alternatively from experimental data and from empty-fullerene calculations. The small differences between the alternative geometries were sufficient to cause significant quantitative changes in the computed binding energies but, except for predicting Xe@C60 to be unstable, did not fundamentally alter our qualitative description of the results. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [ABSTRACT FROM AUTHOR]

Like most aquatic plants, the pondweeds (Potamogetonaceae) are among the most phenotypically reduced and plastic of all angiosperms. As such, hypotheses of structural homology present difficulties for morphological phylogenetic reconstruction. We used non-coding nuclear and plastid DNA data to address Potamogetonaceae relationships and accompanying issues in character evolution and biogeography. Genera currently assigned to Potamogetonaceae, plus Zannichellia, formed a strongly supported monophyletic group. Potamogeton and Stuckenia ( Potamogeton subg. Coleogeton) were both resolved as monophyletic. Within Potamogeton proper, two major clades followed the traditional split between broad- and narrow-leaved species, with the latter condition optimized as basal. Heterophylly (submerged plus floating leaves) has evolved several times, and the ancestral distribution for Potamogeton appears to be Northern Hemispheric. Our phylogenetic results have provided a useful genetic framework from which to interpret morphological, cytological and biogeographical evolution. © The Willi Hennig Society 2006. [ABSTRACT FROM AUTHOR]

The article discusses the use of Gerbera hybrida plant variety as a model system for plant developmental and biosynthetic study. Gerbera offers great potential for comparative developmental study within a single genotype. In addition, the plant variety shows an impressive spectrum of color patterns, displaying responses to developmental cues at all important morphological levels.

B-function MADS-box genes play crucial roles in floral development in model angiosperms. We reconstructed the structural and functional implications of B-function gene phylogeny in the earliest extant flowering plants based on analyses that include 25 new AP3 and P1 sequences representing critical lineages of the basalmost angiosperms: Amborella, Nuphar (Nymphaeaceae), and Illicium (Austrobaileyales). The ancestral size of exon 5 in P1-homologues is 42 bp, typical of exon 5 in other plant MADS-box genes. This 42-bp length is found in P1-homologues from Amborella and Nymphaeaceae, successive sisters to all other angiosperms. Following these basalmost branches, a deletion occurred in exon 5, yielding a length of 30 bp, a condition that unites all other angiosperms. Several shared amino acid strings, including a prominent "DEAER" motif, are present in the AP3- and PI-homologues of Amborella. These may be ancestral motifs that were present before the duplication that yielded the AP3 and P1 lineages and subsequently were modified after the divergence of Amborella. Other structural features were identified, including a motif that unites the previously described TM6 dade and a deletion in AP3-homologues that unites all Magnoliales. Phylogenetic analyses of AP3- and PI-homologues yielded gene trees that generally track organismal phylogeny as inferred by multigene data sets. With both AP3 and P1 amino acid sequences, Amborella and Nymphaeaceae are sister to all other angiosperms. Using nonparametric rate smoothing (NPRS), we estimated that the duplication that produced the AP3 and P1 lineages occurred approximately 260 mya (231-290). This places the duplication after the split between extant gymnosperms and angiosperms, but well before the oldest angiosperm fossils. A striking similarity in the multimer-signalling C domains of the Amborella proteins suggests the potential for the formation of unique transcription-factor complexes. The earliest angiosperms may have been biochemically flexible in their B function and "tinkered" with floral organ identity. [ABSTRACT FROM AUTHOR]

Phylogenetic relationships and biogeography of the genus Cerastium were studied using sequences of three noncoding plastid DNA regions (trnL intron, trnL-trnF spacer, and psbA-trnH spacer). A total of 57 Cerastium taxa was analyzed using two species of the putative sister genus Stellaria as outgroups. Maximum parsimony analyses identified four clades that largely corresponded to previously recognized infrageneric groups. The results suggest an Old World origin and at least two migration events into North America from the Old World. The first event possibly took place across the Bering land bridge during the Miocene. Subsequent colonization of South America occurred after the North and South American continents joined during the Pliocene. A more recent migration event into North America probably across the northern Atlantic took place during the Quaternary, resulting in the current circumpolar distribution of the Arctic species. Molecular clock dating of major biogeographic events was internally consistent on the phylogenetic trees. The arctic high-polyploid species form a polytomy together with some boreal and temperate species of the C. tomentosum group and the C. arvense group. Lack of genetic variation among the arctic species probably indicates a recent origin. The annual life form is shown to be of polyphyletic origin. [ABSTRACT FROM AUTHOR]

The Hawaiian endemic mints, which comprise 58 species of dry-fruited Haplostachys and fleshy-fruited Phyllostegia and Stenogyne, represent a major island radiation that likely originated from polyploid hybrid ancestors in the temperate North American Stachys lineage. In contrast with considerable morphological and ecological diversity among taxa, sequence variation in the nrDNA 5S non-transcribed spacer was found to be remarkably low, which when analyzed using standard parsimony resulted in a lack of phylogenetic resolution among accessions of insect-pollinated Phyllostegia and bird-pollinated Stenogyne. However, many within-individual nucleotide polymorphisms were observed, and under the assumption that they could contain phylogenetic information, these ambiguities were recoded as new character states. Substantially more phylogenetic structure was obtained with these data, including the resolution of most Stenogyne species into a monophyletic group with an apparent recent origin on O’ahu (⩽3.0 My) or the Maui Nui island complex (⩽2.2 My). Subsequent diversification appears to have involved multiple inter-island dispersal events. Intergeneric placements for a few morphotypes, seemingly misplaced within either Phyllostegia or Stenogyne, may indicate reticulation as one polymorphism-generating force. For a finer scale exploration of hybridization, preliminary AFLP fragment data were examined among putative hybrids of Stenogyne microphylla and S. rugosa from Mauna Kea, Hawai’i, that had been identified based on morphology. Cladistic analysis (corroborated by multivariate correspondence analysis) showed the morphologically intermediate individuals to group in a strongly supported monophyletic clade with S. microphylla. Therefore, reticulation could be both historic and active in Stenogyne, and perhaps a force of general importance in the evolution of the Hawaiian mints. The relatively greater extent of lineage-sorted polymorphisms in Stenogyne may indicate selective differentiation from other fleshy-fruited taxa, perhaps through the agency of highly specialized bird pollinators that restricted gene flow with other Hawaiian mint morphotypes. [Copyright &y& Elsevier]

The Hawaiian endemic mints constitute a major island radiation, displaying a remarkable diversity of floral, fruit, and vegetative features. Haplostachys and Phyllostegia have flowers associated with insect pollination, whereas Stenogyne has flowers typical of bird pollination. The three genera had been thought to be closely related to East Asian members of Lamioideae tribe Prasieae because of the fleshy nutlets borne by Phyllostegia and Stenogyne. We evaluated the origins of the Hawaiian mints using phylogenetic analyses of DNA sequence data from the plastid rbcL and trnL intron loci and the nuclear ribosomal 5S nontranscribed spacer. The Hawaiian genera were found to be monophyletic but deeply nested inside another lamioid genus, Stachys. In particular, they were found to be most closely related to a group of temperate North American Stachys from the Pacific coast, suggesting that the Hawaiian mints derived from a single colonization event from western North America to the Hawaiian Islands. Furthermore, Stachys, which contains amphiatlantic and transberingian clades, was found to be polyphyletic, with some species more closely related to Gomphostemma, Phlomidoschema, Prasium, and Sideritis than to other species of Stachys. Based on chromosomal evidence and our phylogenetic analyses, we hypothesize that the Hawaiian mints may be polyploid hybrids whose reticulate genomes predate the Hawaiian dispersal event and are derived from Stachys lineages with flowers exhibiting insect- vs. bird-pollination characteristics. Thus, the Hawaiian endemic mints may provide yet another insular system for the combined study of polyploidy, hybrid cladogenesis, and adaptive radiation. [ABSTRACT FROM AUTHOR]

In the carnivorous plant family Lentibulariaceae, the bladderwort lineage (Utricularia and Genlisea) is substantially more species-rich and morphologically divergent than its sister lineage, the butterworts (Pinguicula). Bladderworts have a relaxed body plan that has permitted the evolution of terrestrial, epiphytic, and aquatic forms that capture prey in intricately designed suction bladders or corkscrew-shaped lobster-pot traps. In contrast, the flypaper-trapping butterworts maintain vegetative structures typical of angiosperms. We found that bladderwort genomes evolve significantly faster across seven loci (the trnL intron, the second trnL exon, the trnL–F intergenic spacer, the rps16 intron, rbcL, coxI, and 5.8S rDNA) representing all three genomic compartments. Generation time differences did not show a significant association. We relate these findings to the contested speciation rate hypothesis, which postulates a relationship between increased nucleotide substitution and increased cladogenesis. [Copyright &y& Elsevier]

Presents a study that analyzed DNA sequences from the chloroplast trnL-F region of 154 Rubiaceae and 11 outgroup taxa. Details on the process of extraction, amplification and sequencing of DNA; Discussion on alignment and gap coding; Information on the Gentianales and subfamilies of Rubiceae.

Deals with a study which assessed phylogenic relationships among species of Oleaceae by a cladistic analysis of DNA sequences from two noncoding chloroplast loci. Characteristics of the plant specie Oleaceae; Methods used in the study; Results and discussion.

Investigates the molecular basis of flower development in Asteraceae using the Gerbera hybrida. Isolation and classification of gerbera MADS box cDNAs; Expression patterns in different floret types; Identification of flower organs of wild-type and transgenic gerbera plants.