SQV-7, a protein involved in Caenorhabditis elegans epithelial invagination and early embryogenesis, transports UDP-glucuronic acid, UDP-N- acetylgalactosamine, and UDP-galactose

Caenorhabditis elegans sqv mutants are defective in vulval epithelial invagination and have a severe reduction in hermaphrodite fertility. The gene sqv-7 encodes a multitransmembrane hydrophobic protein resembling nucleotide sugar transporters of the Golgi membrane. A Golgi vesicle enriched fraction of Saccharomyces cerevisiae expressing SQV-7 transported UDP-glucuronic acid, UDP-N-acetylgalactosamine, and UDP-galactose (Gal) in a temperature-dependent and saturable manner. These nucleotide sugars are competitive, alternate, noncooperative substrates. The two mutant sqv-7 missense alleles resulted in a severe reduction of these three transport activities. SQV-7 did not transport CMP-sialic acid, GDP-fucose, UDP-N-acetylglucosamine, UDP-glucose, or GDP-mannose. SQV-7 is able to transport UDP-Gal in vivo, as shown by its ability to complement the phenotype of Madin-Darby canine kidney ricin resistant cells, a mammalian cell line deficient in UDP-Gal transport into the Golgi. These results demonstrate that unlike most nucleotide sugar transporters, SQV-7 can transport multiple distinct nucleotide sugars. We propose that SQV-7 translocates multiple nucleotide sugars into the Golgi lumen for the biosynthesis of glycoconjugates that play a pivotal role in development.

Distribution of the sand-ascidian Seriocarpa rhizoides in surface sediments of Josephine-Bank, North Atlantic (Table 4)

Seriocarpa rhizoides Diehl 1969 was collected in abundance from the calcareous sand of the Josephine Bank (between Portugal and Madeira) during the "Meteor" seamount cruises in 1967. Attachment in this loose soft substratum is effected by fine anchoring strands of the tests. Two irregular series of small polycarp-like hermaphrodite bodies which are embedded in a connective tissue lie directly below the endostyle, forming a tubular compound gonad, but without common ducts. The intermediate nature of the reproductive system with respect to arrangement and structure increases our knowledge about the polygenetic relations of the stylid-genera. Some of the hitherto known ecological facts point to the presumed "seamounts effect" on this species.

El hermafrodito: a propósito de la monstruosidad en la obra de Cristóbal de Castillejo

En la polifacética y satírica obra de Cristóbal de Castillejo es posible encontrar, entre los numerosos temas, el de la monstruosidad del hermafrodito. El tema, abordado en uno de sus poemas, permite conocer los conceptos y tratados de la época, así como la tradición desde la que se trazan una serie de elementos propios de la literatura, cultura y estética del siglo xvi.

Effect of temperature, food availability, and estradiol injection on gametogenesis and gender in the pearl oyster Pinctada margaritifera

The black-lip pearl oyster Pinctada margaritifera is a protandrous hermaphrodite species. Its economic value has led to the development of controlled hatchery reproduction techniques, although many aspects remain to be optimized. In order to understand reproductive mechanisms and their controlling factors, two independent experiments were designed to test hypotheses of gametogenesis and sex ratio control by environmental and hormonal factors. In one, pearl oysters were exposed under controlled conditions at different combinations of temperature (24 and 28°C) and food level (10,000 and 40,000 cells mL−1); whereas in the other, pearl oysters were conditioned under natural conditions into the lagoon and subjected to successive 17β-estradiol injections (100 μg per injection). Gametogenesis and sex ratio were assessed by histology for each treatment. In parallel, mRNA expressions of nine marker genes of the sexual pathway (pmarg-foxl2, pmarg-c43476, pmarg-c45042, pmarg-c19309, pmarg-c54338, pmarg-vit6, pmarg-zglp1, pmarg-dmrt, and pmarg-fem1-like) were investigated. Maximum maturation was observed in the treatment combining the highest temperature (28°C) and the highest microalgae concentration (40,000 cells mL−1), where the female sex tended to be maintained. Injection of 17β-estradiol induced a significant increase of undetermined stage proportion 2 weeks after the final injection. These results suggest that gametogenesis and gender in adult pearl oysters can be controlled by environmental factors and estrogens. While there were no significant effects on relative gene expression, the 3-gene-pair expression ratio model of the sexual pathway of P. margaritifera, suggest a probable dominance of genetic sex determinism without excluding a mixed sex determination mode (genetic + environmental)

Age, growth and reproduction of the Axilary Seabream, "Pagellus acarne" (Risso, 1827), from the South coast of Portugal

Axillary seabream, Pagellus acarne, caught by longlines in the Algarve (Southern Portugal), were sampled between August 1995 and August 1996. Age was studied by counting growth increments on otoliths and the estimated von Bertalanffy parameters were Linf = 28.82 cm, K = 0.29 year-1 and t0 = -1.47 year for males and Linf = 32.30 cm, K = 0.18 year-1 and t0 = -2.56 year for females. Evidence of the annual periodicity of the deposition of increments was found by marginal increment analyses. Macroscopic analysis of the gonads and the gonad somatic index showed that reproduction occurred over an extensive period of time, from May to November. Lengths at first maturity were 18.10 and 17.60 cm for males and females, respectively. This species was characterized as being a protandric hermaphrodite.

Evaluation of floral characteristics of melon hybrids (Cucumis melo l.) in pollinator attractiveness.

Floral morphology and biology are important characteristics for plant-pollinator interactions and may influence the behavior of these agents. This study aimed to determine which floral attributes of different melon hybrids influence this interaction and, consequently, their attractiveness in simultaneous crops. The study was conducted in the region of Petrolina, State of Pernambuco (PE)/Juazeiro, State of Bahia (BA) and Mossoró, State of Rio Grande do Norte (RN), in areas with the following melon hybrids: Yellow type, Piel de Sapo, Cantaloupe and Galia. For studies on floral morphology and biology, hermaphrodites and male flowers of each hybrid were analyzed for their size and nectar chamber size, pollen and nectar production, anthesis time and flower lifespan. Floral visitors were observed simultaneously in hybrids of three types of melon, from 5:00 a.m. to 6:00 p.m., in the two study sites. Evaluations of the corolla diameter and flower height indicated that the hermaphrodite flowers were larger in size than male flowers in all types of melon investigated, in both study sites. As for nectar chamber, male flowers are larger in width, but smaller in height, compared to hermaphrodite flowers. Regarding the volume of nectar, differences were found between floral types for the hybrids evaluated, in the two study sites; the hermaphrodite flowers produced 2-7 times more nectar than male flowers in all studied hybrids. Observations of visits of Apis mellifera to areas with simultaneous flowering of the three types of melon demonstrated differences in the frequency of visits between hybrids, floral type and foraged resource. Flowers of the hybrids Piel de Sapo and Cantaloupe exhibited larger corolla diameter, larger dimensions of the nectar chamber and greater supply of resources for foraging, which could explain the higher number of visits of bees to their flowers in the sites studied.