Evolution of the Adh locus in the Drosophila willistoni group: the loss of an intron, and shift in codon usage

We report here the DNA sequence of the alcohol dehydrogenase gene (Adh) cloned from Drosophila willistoni. The three major findings are as follows: (1) Relative to all other Adh genes known from Drosophila, D. willistoni Adh has the last intron precisely deleted; PCR directly from total genomic DNA indicates that the deletion exists in all members of the willistoni group but not in any other group, including the closely related saltans group. Otherwise the structure and predicted protein are very similar to those of other species. (2) There is a significant shift in codon usage, especially compared with that in D. melanogaster Adh. The most striking shift is from C to U in the wobble position (both third and first position). Unlike the codon-usage-bias pattern typical of highly biased genes in D. melanogaster, including Adh, D. willistoni has nearly 50% G + C in the third position. (3) The phylogenetic information provided by this new sequence is in agreement with almost all other molecular and morphological data, in placing the obscura group closer to the melanogaster group, with the willistoni group farther distant but still clearly within the subgenus Sophophora.      

Physicochemical properties of etherified maize starches

The changes in starch properties due to etherification with allyl glycidyl ether (AGE) have been investigated. After etherification of three different starches (containing 0.9%, 27% and 70% amylose), no appreciable differences in granular appearance were observed, but the granule crystallinity of these starches was changed. Furthermore, the incorporation of AGE in the starch significantly affects its physicochemical properties: the gelatinization temperatures were decreased and the pasting properties were altered. Both the swelling power and the solubility index increased as the degree of substitution (DS) increased. The rheology behaviour of the droplets of swollen granules suspension was studied under shear flow conditions.     

Marine Sponges as Pharmacy

Marine sponges have been considered as a gold mine during the past 50 years, with respect to the diversity of their secondary metabolites. The biological effects of new metabolites from sponges have been reported in hundreds of scientific papers, and they are reviewed here. Sponges have the potential to provide future drugs against important diseases, such as cancer, a range of viral diseases, malaria, and inflammations. Although the molecular mode of action of most metabolites is still unclear, for a substantial number of compounds the mechanisms by which they interfere with the pathogenesis of a wide range of diseases have been reported. This knowledge is one of the key factors necessary to transform bioactive compounds into medicines. Sponges produce a plethora of chemical compounds with widely varying carbon skeletons, which have been found to interfere with pathogenesis at many different points. The fact that a particular disease can be fought at different points increases the chance of developing selective drugs for specific targets.     

Reduction of cell size induced by enod40 in Arabidopsis thaliana

An extensive analysis of organ and cell size was performed in three different Arabidopsis lines transformed with the early nodulin gene enod40 under control of the CaMV35S promoter. All three transgenic lines presented a significant decrease in the mean size of both epidermal internode and leaf mesophyll cells. Flow cytometric and image analysis of enod40-transfected protoplasts prepared from wild-type Arabidopsis cell suspensions showed that transient expression of the gene resulted in reduced forward light scattering (a factor correlated with particle size) and cell size. The direct administration of ENOD40 peptide to fresh protoplasts also resulted in reduced forward scattering with respect to the control and to the administration of unrelated peptides. As far as is known this is the first report documenting a biological effect of enod40 at the cellular level in non-legume plants.     

How trematodes cause limb deformities in amphibians

We used trematode cyst infestation to induce limb deformities in two species of frogs of the genus Rana and compared them to deformities induced by surgical limb bud rotations. The specific deformities produced by both treatments closely resemble those of wild-caught deformed amphibians and are consistent with a known developmental response to disruption of the spatial organization of cells in developing limb buds. Histological analysis showed that trematode cysts cause massive disruption and abnormal cellular growth involving the limb buds of infected individuals. Our results indicate that trematode cyst infestation causes deformities in frogs by perturbation of the positional relationships of cells in developing limb buds. The crippling effects of cyst-infection on frogs may reflect complex co-evolutionary interactions among trematodes, frogs, and other hosts in the trematode's life cycle.     

Biosynthesis of costunolide,dihydrocostunolide, and leucodin. Demonstration of cytochrome p450-catalyzed formation of the lactone ring present in sesquiterpene lactones of chicory

Chicory (Cichorium intybus) is known to contain guaianolides, eudesmanolides, and germacranolides. These sesquiterpene lactones are postulated to originate from a common germacranolide, namely (+)-costunolide. Whereas a pathway for the formation of germacra-1(10),4,11(13)-trien-12-oic acid from farnesyl diphosphate had previously been established, we now report the isolation of an enzyme activity from chicory roots that converts the germacrene acid into (+)-costunolide. This (+)-costunolide synthase catalyzes the last step in the formation of the lactone ring present in sesquiterpene lactones and is dependent on NADPH and molecular oxygen. Incubation of the germacrene acid in the presence of 18O2 resulted in the incorporation of one atom of 18O into (+)-costunolide. The label was situated at the ring oxygen atom. Hence, formation of the lactone ring most likely occurs via C6-hydroxylation of the germacrene acid and subsequent attack of this hydroxyl group at the C12-atom of the carboxyl group. Blue light-reversible CO inhibition and experiments with cytochrome P450 inhibitors demonstrated that the (+)-costunolide synthase is a cytochrome P450 enzyme. In addition, enzymatic conversion of (+)-costunolide into 11(S),13-dihydrocostunolide and leucodin, a guaianolide, was detected. The first-mentioned reaction involves an enoate reductase, whereas the formation of leucodin from (+)-costunolide probably involves more than one enzyme, including a cytochrome P450 enzyme.     

Bud abortion in tulip bulbs studied by magnetic resonance imaging

After storage and subsequent planting of flower bulbs, the flower bud frequently appears to be aborted. This physiological aberration is probably caused by a change in the water status of the bulb and may be initiated during storage. The development of bud abortion in tulip bulbs was studied during long-term dry storage of the bulbs at 5 degrees C. The anatomy of individual tulip bulbs was followed non-invasively with T2-weighted NMR imaging, which allowed the monitoring of the growth of the shoot and daughter bulbs. Quantitative maps of T1 and T2 relaxation times of individual bulbs were used to assess regional changes in the water status of different tissues. Parallel to the NMR measurements, bulbs were planted to assess the ultimate flower quality. Moreover, water content, osmolality of tissue sap and ion leakage of excised shoot and scale tissues were determined to obtain information about the water status and viability of the bulbs. Significant decreases during long-term storage were found in T1 and T2 relaxation times in the shoot and particularly in the stamens. An increase in the osmolality of tissue sap and the decrease in relaxation times in the shoot below a certain threshold value attained after 24 weeks of storage, could be indicative for the emergence of bud abortion in tulips.     

Redefining the role of psr in beta-lactam resistance and cell autolysis of Enterococcus hirae

The contribution of penicillin-binding protein 5 (PBP5) and the PBP5 synthesis repressor (Psr) to the beta-lactam resistance, growth, and cell autolysis of wild-type strain ATCC 9790 and resistant strain R40 of Enterococcus hirae was investigated by disruption or substitution of the corresponding pbp5 and psr genes by Campbell-type recombination. The resulting modifications were confirmed by hybridization and PCR. The low susceptibility of E. hirae to beta-lactams was confirmed to be largely dependent on the presence of PBP5. However, against all expectations, inactivation of psr in ATCC 9790 or complementation of R40 cells with psr did not modify the susceptibility to benzylpenicillin or the growth and cell autolysis rates. These results indicated that the psr gene does not seem to be involved in the regulation of PBP5 synthesis and consequently in beta-lactam resistance or in the regulation of cell autolysis in E. hirae.