ABSTRACT
Natural products continue to be a useful source of new leads for the pharmaceutical industry. Actinomycetes are prolific producers of natural products and one strategy to increase the possibility of discovering novel chemical entities is to screen actinomycetes considered 'rare' in the environment and previously under-represented in natural product screening collections. We describe a method using bacteriophage as a marker to detect these actinomycetes in environmental samples. This method allows samples to be pre-screened for the presence of target actinomycetes before lengthy isolation programmes are undertaken.
Subject(s)
Actinobacteria/isolation & purification , Actinobacteria/virology , Bacteriophages/isolation & purification , Environmental Monitoring/methods , Soil Microbiology , Actinobacteria/classification , Bacteriophages/classificationABSTRACT
To study transmission patterns of human herpesvirus-8 (HHV-8) (Kaposi's sarcoma-associated herpesvirus) in families in Malawi, nucleotide sequences derived from two hypervariable loci of the HHV-8 genome, the V1 and V2 regions of open reading frame K1 (K1/V1 and K1/V2, respectively), were amplified from blood and mouth rinse samples of 22 patients with treated and untreated Kaposi's sarcoma (KS) and their first-degree relatives (n=67). In patients with KS, vincristine therapy was significantly associated with non-detectability of circulating, but not oral, K1/V1 DNA. Intra-familial K1/V1 phylogenetic comparisons of eight families were possible. Both identical and non-identical sequences were observed between family members, suggesting transmission of HHV-8 along both intra- and extra-familial transmission routes.
Subject(s)
Disease Transmission, Infectious , Herpesvirus 8, Human/genetics , Sarcoma, Kaposi/epidemiology , Adolescent , Adult , Amino Acid Sequence , Antineoplastic Agents, Phytogenic/therapeutic use , Child , Child, Preschool , Cloning, Molecular , Consensus Sequence , DNA, Viral/genetics , Female , Humans , Infant , Malawi/epidemiology , Male , Molecular Epidemiology , Molecular Sequence Data , Open Reading Frames , Sarcoma, Kaposi/drug therapy , Sequence Alignment , Vincristine/therapeutic useABSTRACT
A plethora of human pathogens are now resistant to all clinically significant antibiotics causing a crisis, in the treatment and management of infectious diseases, but also presenting a clear danger to future public health. If drug resistance is going to be tackled successfully, new antibiotics must be continually developed to counteract the processes of evolution and natural selection in these populations of pathogens. Despite the introduction of powerful new technologies such as high throughput screening platforms and combinatorial chemistry, natural products still offer structural diversity worthy of screening for biological activity. Functional genomics can revolutionise rational drug design providing new targets for antimicrobial drug discovery. The clusters of genes, encoding enzymes that form bio-synthetic pathways leading to the synthesis of many natural products including polyketides and non-ribosomal peptides, are amenable to modern genetic engineering. Repositioning, deleting and replacing genes in these biosynthetic clusters has resulted in the synthesis of many 'un-natural' natural products. This review examines the engineering of proteins involved in chain initiation on polyketide synthases culminating in the production at high yield of a biologically active erythromycin derivative.