Kilo-Scale GMP Synthesis of Renewable Semisynthetic Vaccine-Grade Squalene.

Emulsions of the triterpene squalene ((6E,10E,14E,18E)-2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaene, CAS 111-02-4) have been used as adjuvants in influenza vaccines since the 1990s. Traditionally sourced from shark liver oil, the overfishing of sharks and concomitant reduction in the oceanic shark population raises sustainability issues for vaccine adjuvant grade squalene. We report a semisynthetic route to squalene meeting current pharmacopeial specifications for use in vaccines that leverages the ready availability of trans-ß-farnesene ((6E)-7,11-dimethyl-3-methylene-1,6,10-dodecatriene, CAS 18794-84-8), manufactured from sustainable sugarcane via a yeast fermentation process. The scalability of the proposed route was verified by a kilo-scale GMP synthesis. We also report data demonstrating the synthesized semi-synthetic squalene's physical stability and biological activity when used in a vaccine adjuvant formulation.

Sporolides A and B: structurally unprecedented halogenated macrolides from the marine actinomycete Salinispora tropica.

[structure: see text] Analysis of the fermentation broth of a strain of the marine actinomycete Salinispora tropica has led to the isolation of two unprecedented macrolides, sporolides A (1) and B (2). The structures and absolute stereochemistries of both metabolites were elucidated using a combination of NMR spectroscopy and X-ray crystallography.

Engineered biosynthesis of geldanamycin analogs for Hsp90 inhibition.

Geldanamycin, a polyketide natural product, is of significant interest for development of new anticancer drugs that target the protein chaperone Hsp90. While the chemically reactive groups of geldanamycin have been exploited to make a number of synthetic analogs, including 17-allylamino-17-demethoxy geldanamycin (17-AAG), currently in clinical evaluation, the "inert" groups of the molecule remain unexplored for structure-activity relationships. We have used genetic engineering of the geldanamycin polyketide synthase (GdmPKS) gene cluster in Streptomyces hygroscopicus to modify geldanamycin at such positions. Substitutions of acyltransferase domains were made in six of the seven GdmPKS modules. Four of these led to production of 2-desmethyl, 6-desmethoxy, 8-desmethyl, and 14-desmethyl derivatives, including one analog with a four-fold enhanced affinity for Hsp90. The genetic tools developed for geldanamycin gene manipulation will be useful for engineering additional analogs that aid the development of this chemotherapeutic agent.

An individualized psychosocial approach for "treatment resistant" behavioral symptoms of dementia among aged care residents.

BACKGROUND: Behavioral symptoms of dementia are common among residents in mainstream aged care settings, and have a substantial impact on residents and professional caregivers. This study evaluated the impact of individualized psychosocial interventions for behavioral symptoms through a small preliminary study. METHOD: Interventions were delivered to a patient group of 31 psychogeriatric aged care residents who presented with behavioral symptoms of dementia that had failed to respond to pharmacological treatment approaches. Outcome data on severity of behaviors, health service utilization and staff burden of care were collected. RESULTS: A modest but significant reduction in staff ratings of the severity of aggressive and verbally agitated behavioral symptoms was found, with an associated reduction in their perceptions of the burden of caring for these patients. Reduced behavioral disturbance was associated with a reduction in the requirement for primary care consultations, and all participants were able to continue to reside in mainstream aged care facilities, despite an increase in the severity of dementia. CONCLUSIONS: This study supported the use of individualized psychological strategies for behavioral symptoms at all stages of dementia. Methodological limitations of this preliminary study are discussed.

Controlled trial of dementia training with a peer support group for aged care staff.

OBJECTIVE: This study evaluated the impact of an eight-session training program for aged care staff in managing dementia-related challenging behaviours. Participation in the training program with an additional five-session peer support group was compared with both participation in training only and a wait-list control condition. METHODS: Outcomes were evaluated for 90 participating staff members and 113 residents with challenging behaviours from six aged care facilities. Measures of staff attitudes and the behaviours of staff and residents were collected pre- and post-intervention, and at six month follow-up. RESULTS: Staff members in both dementia training groups reported improved attitudes regarding their knowledge and skills in managing residents with challenging behaviours, immediately after the training and six months later. Facility supervisors rated the nursing performance of trained staff more positively, particularly those who participated in a peer support group. The dementia training programs, whether with or without the inclusion of peer support, did not impact on levels of staff burnout or substantially reduce the level of challenging behaviours among aged care residents. CONCLUSIONS: While training programs may impact positively on staff performance, organisational characteristics of aged care facilities, including low levels of management support for staff training initiatives, limit the potential outcomes. Methodological limitations are discussed.

Insights into the biosynthesis of the benzoquinone ansamycins geldanamycin and herbimycin, obtained by gene sequencing and disruption.

Geldanamycin and the closely related herbimycins A, B, and C were the first benzoquinone ansamycins to be extensively studied for their antitumor properties as small-molecule inhibitors of the Hsp90 protein chaperone complex. These compounds are produced by two different Streptomyces hygroscopicus strains and have the same modular polyketide synthase (PKS)-derived carbon skeleton but different substitution patterns at C-11, C-15, and C-17. To set the stage for structural modification by genetic engineering, we previously identified the gene cluster responsible for geldanamycin biosynthesis. We have now cloned and sequenced a 115-kb segment of the herbimycin biosynthetic gene cluster from S. hygroscopicus AM 3672, including the genes for the PKS and most of the post-PKS tailoring enzymes. The similarities and differences between the gene clusters and biosynthetic pathways for these closely related ansamycins are interpreted with support from the results of gene inactivation experiments. In addition, the organization and functions of genes involved in the biosynthesis of the 3-amino-5-hydroxybenzoic acid (AHBA) starter unit and the post-PKS modifications of progeldanamycin were assessed by inactivating the subclusters of AHBA biosynthetic genes and two oxygenase genes (gdmM and gdmL) that were proposed to be involved in formation of the geldanamycin benzoquinoid system. A resulting novel geldanamycin analog, KOS-1806, was isolated and characterized.

New cytotoxic salinosporamides from the marine Actinomycete Salinispora tropica.

An extensive study of the secondary metabolites produced by the obligate marine actinomycete Salinispora tropica (strain CNB-392), the producing microbe of the potent proteasome inhibitor salinosporamide A (1), has led to the isolation of seven related gamma-lactams. The most important of these compounds were salinosporamide B (3), which is the deschloro-analogue of 1, and salinosporamide C (4), which is a decarboxylated pyrrole analogue. New SAR data for all eight compounds, derived from extensive testing against the human colon carcinoma HCT-116 and the 60-cell-line panel at the NCI, indicate that the chloroethyl moiety plays a major role in the enhanced activity of 1.

Production of 8-demethylgeldanamycin and 4,5-epoxy-8-demethylgeldanamycin from a recombinant strain of Streptomyces hygroscopicus.

Two new geldanamycin derivatives produced by genetic engineering of Streptomyces hygroscopicus strain K309-27-1 were isolated and characterized. Removal of the 8-methyl group of geldanamycin was achieved by replacing the AT4 domain of the polyketide synthase with a malonyl AT domain. The resulting strain produced 8-demethyl geldanamycin (2) and 4,5-epoxy-8-demethylgeldanamycin (3). The structures of both molecules were elucidated through interpretation of 1D and 2D NMR data as well as comparison with authentic geldanamycin derivatives. Compounds 2 and 3 displayed moderate cytotoxicity against the human breast cancer cell line SK-BR-3.