Morpho-Physiological Responses of Two Multipurpose Species from the Tropical Dry Forest to Contrasting Light Levels: Implications for Their Nursery and Field Management.

Understanding the responses that some plants exhibit to acclimatize and thrive in different light environments can serve as a guideline to optimize their production or establishment. Morpho-physiological changes in Crescentia alata and Enterolobium cyclocarpum were examined in response to varying light levels: 25%, 35%, 55% and 70% of photosynthetic photon flux density (PPFD) of total solar radiation. One-month-old seedlings were subjected to the light treatments; subsequently, the effects on morphology, photosynthetic capacity, nutrient status, non-structural carbohydrate reserves (NSC) and growth were evaluated in three-month-old seedlings. Light levels affected several morpho-physiological parameters. C. alata responded better to higher light levels and E. cyclocarpum to lower levels. Particularly, C. alata with 70% PPFD increased its size in height and diameter, and accumulated more biomass in leaves, stems, and roots; it also exhibited higher net assimilation rates, improved nitrogen and phosphorus status and growth. In contrast, E. cyclocarpum with 25% PPFD increased aboveground biomass, nitrogen levels and NSC in leaves. Both species show morpho-physiological changes that determine their ability to acclimatize to different light conditions. This serves as a basis for designing better management strategies in the nursery or field by defining the light environments conducive to a proper functioning.

An efficient synthetic route to O-(2-O-benzyl-3,4-di-O-acetyl-α/ß-l-fucopyranosyl)-trichloroacetimidate.

An efficient synthetic route to prepare O-(2-O-benzyl-3,4-di-O-acetyl-α/ß-l-fucopyranosyl)-trichloroacetimidate from l-fucose was developed by introducing the thiophenyl group at the anomeric center and the benzylidene functional group to protect the 3 and 4 positions. Although three approaches were considered, the best result was obtained when, after the 2-hydroxyl benzylation, both protective groups were simultaneously removed by using acetic anhydride and perchloric acid supported on silica as catalyst. Selective deacetylation of the obtained tri-O-acetate followed by the reaction of the resultant hemiacetal with trichloroacetonitrile and DBU afforded the trichloroacetimidate with an overall yield of 56% from the l-fucose.

Actividad antibacteriana de extractos de frutos de nanchi (Byrsonima crassifolia (L.) Kunth), arrayán (Psidium sartorianum (O. Berg) Nied.) y ayale (Crescentia alata Kunth) / Antibacterial activity of extracts obtained from the nanchi (Byrsonima crassifolia (L.) Kunth), arrayan (Psidium sartorianum (O. Berg) Nied.) and ayale (Crescentia alata Kunth) fruits

Nanchi (Byrsonima crassifolia), arrayan (Psidium sartorianum) and ayale (Crescentia alata) are wild and under-utilized plants from Mexico; their fruits have been used as food and as Mexican traditional remedies against human bacterial infections (e.g. bacillary dysentery). However, scientific reports which support such uses or promote their consumption are scarce. In this work, the antibacterial activities of fruit extracts (i.e. hexanic, HE; chloroformic, CE; and methanolic, ME) were determined by the micro-dilution assay, establishing the Minimum Inhibitory Concentration (MIC) and Minimum Bactericide Concentration (MBC) against 21 human pathogenic bacteria. The HE of arrayan and ayale showed the highest activity against enterobacteria (E. coli, Salmonella spp. and Shigella spp.) (MIC 0.25-2 mg/mL; MBC 0.5-16 mg/mL). The arrayan ME was the most active against the Gram-positive bacteria, showing Staphylococcus aureus the highest sensitivity (MIC 2 mg/mL; MBC 2-4 mg/mL). The presented results support the traditional uses of these plant materials for treating bacterial infectious diseases.

Nanchi (Byrsonima crassifolia), arrayán (Psidium sartorianum) y ayale (Crescentia alata) son plantas silvestres subutilizadas de México; sus frutos son comestibles y usados como medicamentos tradicionales contra infecciones bacterianas humanas (e.g. disentería bacilar). Sin embargo, los reportes científicos que avalen los usos y promuevan su consumo son escasos. En este trabajo se determinó, ensayo de micro-dilución en caldo, la Concentración Mínima Inhibitoria (CMI) y Concentración Mínima Bactericida (CMB), de los extractos de frutos (hexánico, EH; clorofórmico, EC; y metanólico, EM) contra 21 bacterias patógenas humanas. Los EH de arrayán y ayale mostraron la mayor actividad (CMI 0.25-2 mg/mL; CMB 0.5-16 mg/mL) contra enterobacterias (Escherichia coli, Salmonella spp. y Shigella spp.). El EM de arrayán fue el más activo contra bacterias Gram positivas, presentando Staphylococcus aureus la mayor sensibilidad (CMI 2 mg/mL; CMB 2-4 mg/mL). Estos resultados apoyan el uso tradicional de estos materiales en padecimientos asociados al tratamiento de infecciones bacterianas.

Candida rugosa lipase-catalyzed intramolecular O- to N- transacylation of butyryl propranolol in the presence of cyclodextrins.

In the present paper, a novel enzymatic reaction between (R,S)-O-butyryl propranolol (O-BP) and lipase from Candida rugosa in the presence of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) is described. Under the used condition, lipase catalyzed the intramolecular transacylation of O-BP into N-butyryl propranolol (N-BP). Propranolol, the product of the expected hydrolysis reaction, was not detected in the reaction medium. A chiral analysis of the reaction product indicated that lipase showed a preference for (R)-O-butyryl propranolol since it first transformed the (R)-enantiomer and then the corresponding (S)-enantiomer. The influence of different reaction conditions on the initial rate is also studied.