Mammillaria Xaltianguensis (Cactaceae) in Jalisco [Mammillaria xaltianguensis (cactaceae) en Jalisco]

[No abstract available

Mammillaria Xaltianguensis (Cactaceae) in Jalisco [Mammillaria xaltianguensis (cactaceae) en Jalisco]

[No abstract available

Echeveria munizii (Crassulaceae) a new species of epiphyte from tropical Volcán de Colima, Mexico

Echeveria munizii, a new species from the southwestern slopes of Volcán de Colima on the Colima-Jalisco border in western Mexico is described and illustrated. This species belongs to series Gibbiflorae and is most similar to E. fulgens from which it differs in having adaxially sulcate leaves with straight and hyaline margins, olive green to brownish green surface, a fewer flowered inflorescence with fewer flowers per branch, a pink/orange bicolored corolla with the inner surface pale pink to orange, the base of the carpels white, and longer pedicels. A species conservation assessment, undertaken using IUCN criteria, determines Echeveria munizii to be Critically Endangered (CR). © 2014 Magnolia Press

Descripción morfogénica de gametófitos y esporófitos jóvenes de Pleopeltis astrolepis (Liebm.) Fournier (Polypodiaceae-Polypodiidae)

Abstract: We analyzed and described the morphogenetic development of gametophyte and sporophyte of Pleopeltis astrolepis (Liebm.) Fourn. It is an epiphyte species that is distributed from Mexico to Brazil, the specimen was collected in a cloud forest at San Bartolo Tutotepec in the state of Hidalgo, at an altitude of 1,000 meters. The spores were sown in glass franks with natural substrates, some with maquique (fibers of the stem of Cyathea sp.) and another in plant litter (bought in Xochimilco for garden plants). The germination takes place within the sporangia. The gametophyte development was Drynaria type in both substrates, a lot of sporophytes were obtained. The gametophytes were chordate to chordate-lobed shaped and prothallus bisexual. The gametangia were developed in 240 days in maquique and 330 days in plant litter. Ecological aspects of the differences in development are discussed.Resumen: Se analiza y describe el desarrollo morfogénico de los gametófitos y esporófitos de Pleopeltis astrolepis (Liebm.) Fourn. Es una especie epífita que se distribuye desde México hasta Brasil, el ejemplar se recolectó en San Bartolo Tutotepec, en el estado de Hidalgo, a una altitud de 1,000 m. en un bosque mesófilo de montaña. Las esporas se sembraron en frascos de vidrio con sustratos naturales, uno de ellos en maquique (fibras del tallo de Cyathea sp.) y otro en tierra de hoja (comprada en Xochimilco para plantas de jardín). Se elaboraron frascos germinadores para la siembra de las esporas, al tomar las muestras se apreció que la germinación de las mismas se realizó dentro de los esporangios, el desarrollo del gametófito fue tipo Drynaria; en ambos sustratos se obtuvieron gran cantidad de esporófitos. Los prótalos tuvieron forma cordada a cordada-lobulada y fueron bisexuados. Los gametangios se desarrollaron a los 240 días en maquique y a los 330 días en tierra de hoja. Se discuten aspectos ecológicos de las diferencias en el desarrollo

General properties of quantum optical systems in a strong-field limit

We present a re-evaluation of the taxonomic status of Agave gypsophila, for which a narrower circumscription is proposed, and four new species from western Mexico are described and illustrated: Agave abisaii, A. andreae, A. kristenii and A. pablocarrilloi . All four species are narrow endemics occurring on a variety of limestone outcrops and belong to the subgenus Agave and to the Marmoratae species group sensu Berger. They are morphologically related to A. gypsophila s. s. from Guerrero, Mexico, but clearly differ from it in various qualitative and quantitative morphological and ecological characteristics. " Copyright 2013 by the American Society of Plant Taxonomists.",,,,,,"10.1600/036364413X666642",,,"http://hdl.handle.net/20.500.12104/41586","http://www.scopus.com/inward/record.url?eid=2-s2.0-84879308920&partnerID=40&md5=33cbe84643fc8a6aca2c05ffb18bd3c

Rhodomyrtone decreases Staphylococcus aureus SigB activity during exponentially growing phase and inhibits haemolytic activity within membrane vesicles

REIPI/GEIH Study Group.Sigma factor B (SigB) controls the expression of Staphylococcus aureus genes including virulence factors and plays a role in the bacterial secretion system through membrane vesicle production. Inhibition of SigB could attenuate SigB dependent virulence and secretion system. The objective of this study was to determine the effects of rhodomyrtone on SigB and virulence factors related to SigB. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of rhodomyrtone against 67 clinical methicillin-resistant S. aureus isolates were 0.25–8 μg/ml, which were similar to those of vancomycin. Using luciferase gene fused to SigB dependent promoters of asp23, five time reduction in SigB activity was observed when the bacteria were treated with rhodomyrtone for 3 h. Rhodomyrtone significantly reduced SigB activity in a concentration dependent manner in exponentially growing cells (P < 0.05). In addition, sigB mutant was more sensitive towards increasing concentrations of rhodomyrtone than the wild type and yabJ-spoVG mutant. Rhodomyrtone at 0.625 μg/ml reduced the growth of sigB mutant by approximately 99%, compared with the yabJ-spoVG mutant and the wild type. Membrane vesicles were significantly reduced in the bacterial cells when treated with 0.5 × MIC rhodomyrtone (P < 0.05). Decreased haemolytic activity was detected within rhodomyrtone-treated membrane vesicles. The results indicated that rhodomyrtone inhibited S. aureus SigB activity during exponentially growing phase and inhibited haemolytic activity within membrane vesicles.This work was financially supported by The Royal Golden Jubilee Ph.D. Program (Grant No. PHD/0033/2553) and TRF Senior Research Scholar (Grant No. RTA 6180006), the Thailand Research Fund. M.J.R.O. was funded by the 'XXII Programa Propio de Fomento de la Investigación', University of Córdoba