Mutations in SLC34A2 cause pulmonary alveolar microlithiasis and are possibly associated with testicular microlithiasis

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by the deposition of calcium phosphate microliths throughout the lungs. We first identified a PAM locus by homozygosity mapping to 4p15, then identified, by a candidate-gene approach, the gene responsible for the disease as SLC34A2 (the type IIb sodium-phosphate cotransporter gene), which is involved in phosphate homeostasis in several organs. We identified six homozygous exonic mutations in the seven unrelated patients with PAM we studied. Three of the mutations were frameshifts, one was a chain termination, one was an amino acid substitution, and one was a deletion spanning the minimal promoter and the first exon. Absence of functional protein product of the gene is compatible with calcium phosphate deposition in alveolar airspaces. We show that impaired activity of the phosphate transporter is presumably responsible for the microliths and that PAM is a recessive monogenic disease with full penetrance. Testicular microlithiasis (TM) is a disease that is more common than PAM. It is often associated with cancer and infertility. Since the gene we identified is also expressed in testis, we searched for mutations in subjects with TM. In 2 of the 15 subjects with TM we studied, we identified two rare variants, one synonymous and the other noncoding, that are possibly associated with the condition.     

Molecular phylogeny of relict-endemic <Emphasis Type="Italic">Liquidambar orientalis</Emphasis> Mill based on sequence diversity of the chloroplast-encoded <Emphasis Type="Italic">mat</Emphasis>K gene

The genetic diversity and evolutionary divergence in Liquidambar species and Liquidambar orientalis varieties were compared with respect to the matK gene. A total of 66 genotypes from 18 different populations were sampled in southwestern Turkey. The matK region, which is about 1,512 bp in length, was sequenced and studied. L. orientalis, L. styraciflua, and L. formosana had similar magnitude of nucleotide diversity, while L. styraciflua and L. acalycina possessed higher evolutionary divergence. The highest evolutionary divergence was found between L. styraciflua and eastern Asian Liquidambar species (0.0102). However, the evolutionary divergence between L. orientalis and other species was of a similar magnitude. The maximum-parsimony phylogenetic tree showed that L. styraciflua and L. orientalis formed a closer clade while East Asian species were in a separate clade. This suggests that the North Atlantic Land Bridge through southern Greenland may have facilitated continuous distribution of Liquidambar species from southeastern Europe to eastern North America in early Tertiary period. The maximum-parsimony tree with only 18 Oriental sweetgum populations indicated that there were two main clusters: one with mainly L. orientalis var. integriloba and the other with var. orientalis and undetermined populations. High nucleotide diversity (0.0028) and divergence (0.00072) were found in L. orientalis var. integriloba populations and Muğla-1 geographical region. This region could be considered as the major refugium and genetic diversity center for the species. The low genetic diversity and divergence at intraspecies level suggest that L. orientalis populations in Turkey share an ancestral polymorphism from which two varieties may have evolved.     

A brain-derived metric for preferred kinetic stimuli

We here address the question of whether there is any correlation between subjective preference for simple configurations within a specific visual domain such as motion and strength of activity in visual areas in which that domain is emphasized. We prepared several distinctive patterns of dots in motion with various characteristics and asked humans to rate them according to their preference, before and while scanning the activity in their brains with functional magnetic resonance imaging. For simplicity, we restricted ourselves to motion in the fronto-parallel plane. Moving patterns produced activity in areas V1, V2, the V3 complex (V3, V3A, V3B) and V5, but only in areas V5, V3A/B and parietal cortex did the preferred kinetic patterns produce stronger activity when compared with the non-preferred ones. In addition, preferred patterns produced activity within field A1 of medial orbito-frontal cortex (mOFC), which is not otherwise activated by kinetic stimuli. Hence, for these areas, stronger neural activity correlated with subjective preference. We conclude that configurations of kinetic stimuli that are subjectively preferred correlate with stronger activity within early visual areas and within mOFC. This opens up the possibility of more detailed studies to relate subjective preferences to strength of activity in early visual areas and to relate activity in them to areas whose activity correlates with the subjective experience of beauty.     

Chromosome Numbers and Karyotypes of Species of Vernonia sect. Lepidaploa (Asteraceae: Vernonieae)

Vernonia is the largest genus of the tribe Vernonieae (Asteraceae) and comprises more than 1,000 species. In the present study we explore chromosome number and karyotype variation of eight species treated within different subsections of the section Vernonia sect. Lepidaploa. We aimed to explore if these data support the recognition of a single large genus (sensu Baker) or favor its splitting into 22 small genera (sensu Robinson). The species were collected in ??cerrado??, rupicolous and disturbed areas in the states of S?o Paulo and Minas Gerais, Brazil. Chromosome numbers varied from 2n?=?32 to 60. Most chromosomes were small, and the karyotype analysis revealed a predominance of metacentric and some submetacentric chromosomes. The karyotype symmetry in Vernonia was moderate (TF% 32.2 to 45.9), with the most symmetrical karyotype observed in V. rubriramea. The results obtained here did not conclusively support any of the taxonomic proposals for Vernonia due to the absence of distinctive or characteristic karyotype patterns for any of the taxonomic groupings, i.e., sections and subsections (sensu Baker) or new genera (sensu Robinson). Nevertheless, a tenuous relationship was observed between the chromosome numbers reported in the literature, those recorded here, and the taxonomic alterations suggested by Robinson for the genera Lessingianthus, Chrysolaena, and Vernonanthura that were originally part of Vernonia sensu Baker.     

Pollinator Specificity and Convergence in Fly-pollinated Pleurothallis(Orchidaceae) Species: A Multiple Population Approach

We studied the floral biology of 12 populations of five rupicolousPleurothallis(Orchidaceae) species occurring in campo rupestre vegetationat nine localities in Brazil. All of these species are pollinatedby flies belonging to the families Chloropidae and Phoridae.In the five Pleurothallis species studied, all conspecific populationsattracted the same pollinator species. All pollinators werefemales; they laid eggs in flowers of the two nectarless species,but never in the flowers of nectar-presenting species. The twopairs ofPleurothallis species with similar flower morphologiesand odours attracted the same pollinators: P. johannensis -P. fabiobarrosii, pollinated by Tricimba sp. (Chloropidae) andP. teres - P. ochreata pollinated by Megaselia spp. (Phoridae).There was no overlap in the distribution of thePleurothallisspecies that shared pollinators. Despite similarities in floralmorphology and odour, genetic data show that these species pairsare not each other's closest relatives. We hypothesize thatthese similarities are due to convergence in allopatric speciesthat evolved similar pollination mechanisms. Conversely, thereare reasons to believe that adaptation to different pollinationmechanisms occurred in the closely related species P. johannensisand P. teres.Copyright 2001 Annals of Botany Company Pleurothallis, Orchidaceae, floral biology, fly-pollination, Chloropidae, Phoridae, pollinator specificity, campo rupestre     

Introduction to the Philosophical Transactions B Millennium issue. A special Millennium issue edited by S. Zeki

Introduction to the Philosophical Transactions B Millennium issue. A special Millennium issue edited by S. Zeki     

The clinical and functional measurement of cortical (in)activity in the visual brain, with special reference to the two subdivisions (V4 and V4 alpha) of the human colour centre.

We argue below that, at least in studying the visual brain, the old and simple methods of detailed clinical assessment and perimetric measurement still yield important insights into the organization of the visual brain as a whole, as well as the organization of the individual areas within it. To demonstrate our point, we rely especially on the motion and colour systems, emphasizing in particular how clinical observations predicted an important feature of the organization of the colour centre in the human brain. With the use of data from functional magnetic resonance imaging analysed by statistical parametric mapping and independent component analysis, we show that the colour centre is composed of two subdivisions, V4 and V4 alpha the two together constituting the V4 complex of the human brain. These two subdivisions are intimately linked anatomically and act cooperatively. The new evidence about the architecture of the colour centre might help to explain why the syndrome, cerebral achromatopsia, produced by lesions in it is so variable.     

Structure, development and evolution of the androecium in Adansonieae (core Bombacoideae, Malvaceae s.l.)

Androecium development and vasculature were studied in nine species of the Adansonieae clade (core Bombacoideae, Malvaceae s.l.). In early androecium development either distinct pentagonal androecial ring walls or five common petal/androecium primordia are present. Ring walls give rise to five antepetalous and five alternipetalous primary androecial primordia. Common primordia divide into peripheral petal primordia and antepetalous primary androecial primordia. Antepetalous primary androecial primordia split anticlinally into ten primordia-halves, on which secondary androecial primordia are initiated in a centrifugal succession. Androecial lobes are formed by fusion of an alternipetalous primary androecial primordium and its two neighbouring antepetalous primary primordia-halves, a pattern that also occurs in other Malvatheca. Later, tertiary androecial primordia are formed by the subdivision of secondary androecial primordia (except in Adansonia and Ceiba). Each tertiary primordium differentiates into a two-locular androecial unit. At anthesis these two-locular androecial units are often present in pairs, corresponding to the two halves of the same secondary androecial primordium. Androecium development and vasculature imply that the alternipetalous androecial sectors have been reduced in Bombacoideae, a tendency that is shared with other subfamilies of Malvaceae.