Asymmetric reduction of prochiral ketones to chiral alcohols catalyzed by plants tissue

As an important organic compound, chiral alcohols are the key chiral building blocks to many single enantiomer pharmaceuticals. Asymmetric reduction of the corresponding prochiral ketones to produce the chiral alcohols by biocatalysis is one of the most promising routes. Asymmetric reduction of different kinds of non-natural prochiral ketones catalyzed by various plants tissue was studied in this work. Acetophenone, 4'-chloroacetophenone and ethyl 4-chloroacetoacetate were chosen as the model substrates for simple ketone, halogen-containing aromatic ketone and beta-ketoesters, respectively. Apple (Malus pumila), carrot (Daucus carota), cucumber (Cucumis sativus), onion (Allium cepa), potato (Soanum tuberosum), radish (Raphanus sativus) and sweet potato (Ipomoea batatas) were chosen as the biocatalysts. It was found that these kinds of prochiral ketoness could be reduced by these plants tissue with high enantioselectivity. Both R- and S-form configuration chiral alcohols could be obtained. The e.e. and chemical yield could reach about 98 and 80% respectively for acetophenone and 4'-chloroacetophenone reduction reaction with favorable plant tissue. And the e.e. and yield for ethyl 4-chloroacetoacetate reduction reaction was about 91 and 45% respectively.     

ABA may affect the dormancy in triticale caryopses by inhibition of embryo class I RNases,enzymes involved in P<Subscript>i</Subscript> release

The main objective of this study was to analyze the differences in profiles of RNase activities from triticale embryos (Triticosecale, cv. Ugo) between dormant and non-dormant caryopses and to determine the influence of exogenous abscisic acid (ABA) on the activities of these enzymes. The major RNase from the examined tissue was detected following SDS-PAGE, with substrate-based gel assay, described by Yen and Green (Plant Physiol 97:1487–1493, 1991). The activities of enzymes were characterized according to their pH optima, ion dependence, EDTA sensitivity and DNase activity. In embryos with arrested growth (in a natural way by dormancy or artificially by ABA treatment), the activity of two enzymes—24 and 27 kDa—belonging to class I RNases was completely inhibited, whereas that of two other RNases of this family—23 and 25 kDa—was detectable. However, the activity of the class I ribonucleases (enzymes responsible for cellular P_i release) was very low. Moreover, in contrast with non-dormant caryopses, imbibing embryos of dormant or ABA-treated seeds contained 13- and 14-kDa enzymes. These enzymes have not been classified so far, and their specific properties are different from the generally accepted properties of ribonucleolytic enzymes. In addition to the above results, the P_i content in the analyzed samples was determined by the Ames (Methods Enzymol 8:115–118, 1966) method. The results suggest a very low and constant level of inorganic phosphate in dormant samples as well as an evidently decreasing P_i content in embryos under the influence of ABA treatment. The inhibition of the class I RNases activity induced by abscisic acid implies that one of the roles of ABA in seed dormancy may consist in arresting the catabolic release of P_i, which results in retarding the embryo’s growth.     

Experience with using Ellenberg’s <Emphasis Type=Italic>R</Emphasis> indicator values in Slovakia: Oligotrophic and mesotrophic submontane broad-leaved forests

Ellenberg’s indicator values have been suggested as useful method of estimating site conditions using plants. We examined whether Ellenberg’s R values are suitable for indicating soil reaction and if calibration to physical pH measurements can improve bioindication in oligotrophic and mesotrophic submontane broad-leaved forests in Slovakia. Vegetation relevés and pH-H₂O and pH-CaCl₂ soil reaction were recorded for this purpose. Ellenberg’s R values (R _e) were compared to Jurko’s indicator values (R _j) and a set of species R values and tolerances (T), which were calibrated with physical pH data using the weighted averaging (R _w, T _w) and Huisman-Olff-Fresco modelling (R _h, T _h). Original R _e values were then recalibrated with measured pH data to establish new, adjusted set of scores (R _c, T _c) at Ellenberg’s scale. The Re values are significantly correlated with the other R values, and they demonstrate similar frequency distribution to R _j and R _w values for the studied species pool. The frequency distribution becomes similar across all the R values when indifferent species were excluded. The performance of all the indicator values in terms of bioindication was tested. Relevé means of the R values were regressed on the field pH measurements. The performance of bioindication varied from 36% to 49% of the explained variance for pH-CaCl₂, with the R _e and R _c values yielding 46% and 49% respectively. The bioindication slightly improved for all calibrated methods (R _w, R _h and R _c) when species were weighted inversely with their tolerances — the performance varied from 42% to 51%, and the R _c values performed most effectively. We concluded that Ellenberg’s R values represent a powerful system for bioindicating soil acidity when compared to the other alternatives, with pH-CaCl₂ showing better results than pH-H₂O. Recalibration of Ellenberg’s values to the measured data improved the indicator system.     

Sexual incompatibility in Rosaceae fruit tree species: molecular interactions and evolutionary dynamics

Fruit crops have a growing economic importance worldwide and molecular genetics might be useful in solving many problems that arise during commercial production. One of the fields that have attracted intense attention is the molecular basis of self-incompatibility that may result in low fruit set. In tree fruits of the Rosaceae family, the incompatibility reactions take place between the pistil S-ribonuclease (S-RNase) and the pollen-expressed S-haplotype specific F-box (SFB) proteins. In most cases, the loss of self-incompatibility was associated with mutations in the S-RNase or SFB genes. A total of 27 non-functional S-haplotypes have been identified and characterized, most (24) of which emerged as a consequence of natural mutations. In the Prunoideae, most haplotypes are pollen-part mutants (50 %), while 8 are stylar-part mutants (36 %), one haplotype shows both pollen- and stylar-part mutations, and molecular changes for two haplotypes still have not been clarified. In contrast, non-functional natural haplotypes in the Maloideae are all stylar-part mutants. The analysis of such mutants may shed light on underlying molecular mechanisms as was the case with the establishment of the general inhibitor model that describes interactions between pollen and pistil S-proteins. However, several other molecules were supposed to contribute to the molecular interactions, at least in Solanaceae, a family with a similar self-incompatibility system. This review also endeavours to delineate the evolutionary implications of the S-locus mutations and collect limited data on non-S-locus molecular interactions and signaling events after self- and cross-pollination of fruit tree species.     

<Emphasis Type=Italic>Lockhartia viruensis</Emphasis> (Orchidaceae-Oncidiinae), a new species from Roraima state,Brazilian Amazonia region

A new species, Lockhartia viruensis, is described and illustrated from the state of Roraima, in the Brazilian Amazon, and its affinities are discussed. The new species is similar to L. imbricata, but differs by having an entire lip with an obtuse to rounded apex, a callus on the disk of the lip with a longitudinal row of papillae with a rounded apex, and the margin of the column wings entire.     

Biased Sex Ratios in Plants: Theory and Trends

This paper examines the history of sex ratio theory and the effects of multiple variables on individual and population sex ratios. It also provides examples where plants have been used to test major predictions of sex ratio theory. Then, using over 200 studies from the literature, dioecious plant species are categorized based on their life form, pollination agent, fruit dispersal agent, and sex ratio. A loglinear analysis is used to look at possible correlations between the sex ratio of a population and other life history characteristics. These data are used to examine the predictions made by De Jong et al. (Journal of Evolutionary Biology 15:7, 2002), that relative pollen and seed dispersal distances can be used to predict sex ratio bias. Despite the limited sample size, strong relationships are still observed. 93% of insect pollinated dioecious vines that have biotically dispersed fruit have male-biased sex ratios. Conversely, 61% of shrubs that are wind pollinated and have abiotic fruit dispersal have female-biased sex ratios.     

Sesame Utilization in China: New Archaeobotanical Evidence from Xinjiang

Sesame Utilization in China: New Archaeobotanical Evidence from Xinjiang. A cache of sesame (Sesamum indicum L.) seeds, discovered in the Thousand Buddha Grottoes at Boziklik, Turpan, China, dating to ca. 700 years before present (BP), is hard evidence of their use in China since that time. Morphological and anatomical features suggest a white sesame cultivar. The sizeable quantity unearthed implies that sesame was a valued commodity that could provision the monks and enrich the diet of ancient inhabitants as an oil source.     

Pliocene coastal palaeomorphology and ostracod faunas of the Bass Strait hinterland,southeast Australia

Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, southeastern Australia yield extensive fossil proxy data relevant to the interpretation of high sea level coastal palaeomorphology. Within the Pliocene Whalers Bluff Formation exposed in coastal cliffs near the township of Portland, Victoria, marine microfossil faunas delineate two broad cycles of deposition. Both these sedimentary cycles are bound below by unconformity surfaces. Within the lower sedimentary cycle, a basal stress-tolerant (low diversity) marginal marine microfossil fauna devoid of ostracods and suggestive of bottom-water hypoxia, is succeeded by a diverse shallow marine ostracod fauna dominated by stenohaline species indicative of a sheltered (but open) oceanic embayment. This lower sedimentary cycle has an early Pliocene (Zanclean) age. Equivalent shallow marine (e.g. coastal embayment) deposits occur broadly across the coastal hinterland of southeastern Australia—reflecting the generally higher global sea levels of this time. The upper cycle in the cliff exposures at Portland is late Pliocene (Piacenzian) in age. Equivalent deposits across the Bass Strait hinterland are restricted to former incised river valley settings. Euryhaline estuarine/coastal lagoon Ostracoda are present throughout the upper cycle in the Portland cliffs. These are associated with a low diversity microfauna at the base of the upper cycle and a high diversity microfauna towards the top of the cycle. Early Pliocene coastal marine deposits can be distinguished from late Pliocene coastal marine deposits across the northern Bass Strait hinterland on the basis of the presence or absence of certain open marine (‘stenohaline’) ostracod species.