Stereoselective synthesis of (1-alkoxyalkyl) α- and β-d-glucopyranosiduronates (acetal-glucopyranosiduronates): A new approach to specific cytostatics for the treatment of cancer

The reaction of methyl 2,3,4,6-tetra-O-acetyl-1-O-trimethylsilyl-β- (5) and -α-d-glucopyranuronate (6) severally with the dimethyl or diethyl acetals of formaldehyde, bromoacetaldehyde, propionaldehyde, 3-benzyloxypropionaldehyde, 5-carboxypentanal, and 2-bromohexanal in the presence of catalytic amounts of trimethylsilyl trifluoromethanesulfonate at −78° gave the corresponding (1-alkoxyalkyl) α- and β-glycosides (acetal-glucopyranosiduronates) with retention of configuration at C-1 in yields of 41–91%. Instead of the dialkyl acetals, the corresponding aldehydes and alkyl trimethylsilyl ether can be used. Deacetylation gave the corresponding methyl (acetal-β- and -α-d-glucopyranosid)uronates in good yield. De-esterification of methyl [(1R)-1-methoxybutyl β-d-glucopyranosid]uronate with esterase gave the acetal-β-d-glucopyranosiduronic acid which was an excellent substrate for β-d-glucuronidase.     

Die Buche. Eine Kultur‐ und Wirtschaftsgeschichte

The Beech forests: A cultural and socio‐economic history The German strategy of maintaining biodiversity aims at an establishment of wilderness areas. Mainly beech forests shall serve as UNESCO world heritage. Here we ask, if there are any “natural” beech forests. This tree species is closely linked to human development, and at present this species is less endangered than the accompanying species of Acer, Fraxinus, Quercus and other broad leaved species.     

Comprehensive Approach to Improving Maternal Health and Achieving MDG 5: Report from the Mountains of Lesotho

Background

Although it is now widely recognized that reductions in maternal mortality and improvements in women''s health cannot be achieved through simple, vertical strategies, few programs have provided successful models for how to integrate services into a comprehensive program for maternal health. We report our experience in rural Lesotho, where Partners In Health (PIH) in partnership with the Ministry of Health and Social Welfare implemented a program that provides comprehensive care of pregnant women from the community to the clinic level.

Methods

Between May and July 2009, PIH trained 100 women, many of whom were former traditional birth attendants, to serve as clinic-affiliated maternal health workers. They received performance-based incentives for accompanying pregnant women during antenatal care (ANC) visits and facility-based delivery. A nurse-midwife provided ANC and delivery care and supervised the maternal health workers. To overcome geographic barriers to delivering at the clinic, women who lived far from the clinic stayed at a maternal lying-in house prior to their expected delivery dates. We analyzed data routinely collected from delivery and ANC registers to compare service utilization before and after implementation of the program.

Results

After the establishment of the program, the average number first ANC visits increased from 20 to 31 per month. The clinic recorded 178 deliveries in the first year of the program and 216 in the second year, compared to 46 in the year preceding the program. During the first two years of the program, 49 women with complications were successfully transported to the district hospital, and no maternal deaths occurred among the women served by the program.

Conclusions

Our results demonstrate that it is possible to achieve dramatic improvements in the utilization of maternal health services and facility-based delivery by strengthening human resource capacity, implementing active follow-up in the community, and de-incentivizing home births.     

F99 is Critical for Dimerization and Activation of South African HIV-1 Subtype C Protease

HIV-1 protease (PR) is an obligate homodimer which plays a pivotal role in the maturation and hence propagation of HIV. Although successful developments on PR active site inhibitors have been achieved, the major limiting factor has been the emergence of HIV drug-resistant strains. Disruption of the dimer interface serves as an alternative mechanism to inactivate the enzyme. The terminal residue, F99, was mutated to an alanine to investigate its contribution to dimer stability in the South African HIV-1 subtype C (C-SA) PR. The F99A PR and wild-type C-SA PR were overexpressed and purified. The activities of the PRs and their ability to bind an active site inhibitor, acetyl-pepstatin, were determined in vitro. The F99A PR showed no activity and the inability to bind to the inhibitor. Secondary and quaternary structure analysis were performed and revealed that the F99A PR is monomeric with reduced β-sheet content. The mutation of F99 to alanine disrupted the presumed ‘lock-and-key’ motif at the terminal dimer interface, in turn creating a cavity at the N- and C-terminal antiparallel β-sheet. These findings support the design of inhibitors targeting the C-terminus of the C-SA PR, centered on interactions with the bulky F99.     

Different facets of tree sapling diversity influence browsing intensity by deer dependent on spatial scale

Browsing of tree saplings by deer hampers forest regeneration in mixed forests across Europe and North America. It is well known that tree species are differentially affected by deer browsing, but little is known about how different facets of diversity, such as species richness, identity, and composition, affect browsing intensity at different spatial scales. Using forest inventory data from the Hainich National Park, a mixed deciduous forest in central Germany, we applied a hierarchical approach to model the browsing probability of patches (regional scale) as well as the species‐specific proportion of saplings browsed within patches (patch scale). We found that, at the regional scale, the probability that a patch was browsed increased with certain species composition, namely with low abundance of European beech (Fagus sylvatica L.) and high abundance of European ash (Fraxinus excelsior L.), whereas at the patch scale, the proportion of saplings browsed per species was mainly determined by the species’ identity, providing a “preference ranking” of the 11 tree species under study. Interestingly, at the regional scale, species‐rich patches were more likely to be browsed; however, at the patch scale, species‐rich patches showed a lower proportion of saplings per species browsed. Presumably, diverse patches attract deer, but satisfy nutritional needs faster, such that fewer saplings need to be browsed. Some forest stand parameters, such as more open canopies, increased the browsing intensity at either scale. By showing the effects that various facets of diversity, as well as environmental parameters, exerted on browsing intensity at the regional as well as patch scale, our study advances the understanding of mammalian herbivore–plant interactions across scales. Our results also indicate which regeneration patches and species are (least) prone to browsing and show the importance of different facets of diversity for the prediction and management of browsing intensity and regeneration dynamics.     

Identification and Characterization of IgdE,a Novel IgG-degrading Protease of Streptococcus suis with Unique Specificity for Porcine IgG

Streptococcus suis is a major endemic pathogen of pigs causing meningitis, arthritis, and other diseases. Zoonotic S. suis infections are emerging in humans causing similar pathologies as well as severe conditions such as toxic shock-like syndrome. Recently, we discovered an IdeS family protease of S. suis that exclusively cleaves porcine IgM and represents the first virulence factor described, linking S. suis to pigs as their natural host. Here we report the identification and characterization of a novel, unrelated protease of S. suis that exclusively targets porcine IgG. This enzyme, designated IgdE for immunoglobulin G-degrading enzyme of S. suis, is a cysteine protease distinct from previous characterized streptococcal immunoglobulin degrading proteases of the IdeS family and mediates efficient cleavage of the hinge region of porcine IgG with a high degree of specificity. The findings that all S. suis strains investigated possess the IgG proteolytic activity and that piglet serum samples contain specific antibodies against IgdE strongly indicate that the protease is expressed in vivo during infection and represents a novel and putative important bacterial virulence/colonization determinant, and a thus potential therapeutic target.     

Stereoselective synthesis of (1-alkoxyalkyl) alpha- and beta-D-glucopyranosiduronates (acetal-glucopyranosiduronates): a new approach to specific cytostatics for the treatment of cancer

The reaction of methyl 2,3,4,6-tetra-O-acetyl-1-O-trimethylsilyl-beta- and -alpha-D-glucopyranuronate severally with the dimethyl or diethyl acetals of formaldehyde, bromoacetaldehyde, propionaldehyde, 3-benzyloxypropionaldehyde, 5-carboxypentanal, and 2-bromohexanal in the presence of catalytic amounts of trimethylsilyl trifluoromethanesulfonate at -78 degrees gave the corresponding (1-alkoxyalkyl) alpha- and beta-glycosides (acetal-glucopyranosiduronates) with retention of configuration at C-1 in yields of 41-91%. Instead of the dialkyl acetals, the corresponding aldehydes and alkyl trimethylsilyl ether can be used. Deacetylation gave the corresponding methyl (acetal-beta- and -alpha-D-glucopyranosid)uronates in good yield. De-esterification of methyl [(1R)-1-methoxybutyl beta-D-glucopyranosid]uronate with esterase gave the acetal-beta-D-glucopyranosiduronic acid which was an excellent substrate for beta-D-glucuronidase.