Beyond the beneficial effects of translocations as an effective tool for the genetic restoration of isolated populations

Translocations are becoming increasingly popular as appropriate management strategies for the genetic restoration of endangered species and populations. Although a few studies have shown that the introduction of novel alleles has reversed the detrimental effects of inbreeding over the short-term (i.e., genetic rescue), it is not clear how effective such translocations are for both maintaining neutral variation that may be adaptive in the future (i.e., genetic restoration) and increasing population viability over the long-term. In addition, scientists have expressed concerns regarding the potential genetic swamping of locally adapted populations, which may eliminate significant components of genetic diversity through the replacement of the target population by the source individuals used for translocations. Here we show that bird translocations into a wild population of greater prairie-chickens (Tympanuchus cupido pinnatus) in southeastern Illinois were effective in both removing detrimental variation associated with inbreeding depression as well as restoring neutral genetic variation to historical levels. Furthermore, we found that although translocations resulted in immediate increases in fitness, the demographic recovery and long-term viability of the population appears to be limited by the availability of suitable habitat. Our results demonstrate that although translocations can be effective management tools for the genetic restoration of wild populations on the verge of extinction, their long-term viability may not be guaranteed unless the initial conditions that led to most species declines (e.g., habitat loss) are reversed.     

Laminin-511 and integrin beta-1 in hair follicle development and basal cell carcinoma formation

Background  

Initiation of the hair follicle placode and its subsequent growth, maturation and cycling in post-natal skin requires signaling interactions between epithelial cells and adjacent dermal cells and involves Shh signaling via the primary cilium. Previous reports have implicated laminins in hair follicle epithelial invagination.     

Synthesis and SAR studies of very potent imidazopyridine antiprotozoal agents

Compounds 10a (IC50 110 pM) and 21 (IC50 40 pM) are the most potent inhibitors of Eimeria tenella cGMP-dependent protein kinase activity reported to date and are efficacious in the in vivo antiparasitic assay when administered to chickens at 12.5 and 6.25 ppm levels in the feed. However, both compounds are positive in the Ames microbial mutagenesis assay which precludes them from further development as antiprotozoal agents in the absence of negative lifetime rodent carcinogenicity studies.     

Synthesis and SAR of 2-(4-fluorophenyl)-3-pyrimidin-4-ylimidazo[1,2-a]pyridine derivatives as anticoccidial agents

Compounds 10a-10d and 10i are very potent inhibitors of Eimeria tenella cGMP-dependent protein kinase (0.081-0.32 nM) and are very efficacious antiparasitic agents in vivo when administered to chickens at 12.5-25 ppm levels in the feed.     

DNase expression allows the pathogen group A Streptococcus to escape killing in neutrophil extracellular traps

The innate immune response plays a crucial role in satisfactory host resolution of bacterial infection. In response to chemotactic signals, neutrophils are early responding cells that migrate in large numbers to sites of infection. The recent discovery of secreted neutrophil extracellular traps (NETs) composed of DNA and histones opened a novel dimension in our understanding of the microbial killing capacity of these specialized leukocytes. M1 serotype strains of the pathogen Group A Streptococcus (GAS) are associated with invasive infections including necrotizing fasciitis (NF) and express a potent DNase (Sda1). Here we apply a molecular genetic approach of allelic replacement mutagenesis, single gene complementation, and heterologous expression to demonstrate that DNase Sda1 is both necessary and sufficient to promote GAS neutrophil resistance and virulence in a murine model of NF. Live fluorescent microscopic cell imaging and histopathological analysis are used to establish for the first time a direct linkage between NET degradation and bacterial pathogenicity. Inhibition of GAS DNase activity with G-actin enhanced neutrophil clearance of the pathogen in vitro and reduced virulence in vivo. The results demonstrate a significant role for NETs in neutrophil-mediated innate immunity, and at the same time identify a novel therapeutic target against invasive GAS infection.     

Preparation of fluorescent tocopherols for use in protein binding and localization with the alpha-tocopherol transfer protein

Sixteen fluorescent analogues of the lipid-soluble antioxidant vitamin alpha-tocopherol were prepared incorporating fluorophores at the terminus of omega-functionalized 2-n-alkyl-substituted chromanols (1a-d and 4a-d) that match the methylation pattern of alpha-tocopherol, the most biologically active form of vitamin E. The fluorophores used include 9-anthroyloxy (AO), 7-nitrobenz-2-oxa-1,3-diazole (NBD), N-methyl anthranilamide (NMA), and dansyl (DAN). The compounds were designed to function as fluorescent reporter ligands for protein-binding and lipid transfer assays. The fluorophores were chosen to maximize the fluorescence changes observed upon moving from an aqueous environment (low fluorescence intensity) to an hydrophobic environment such as a protein's binding site (high fluorescence intensity). Compounds 9d (anthroyloxy) and 10d (nitrobenzoxadiazole), having a C9-carbon chain between the chromanol and the fluorophore, were shown to bind specifically and reversibly to recombinant human tocopherol transfer protein (alpha-TTP) with dissociation constants of approximately 280 and 60 nM, respectively, as compared to 25 nM for the natural ligand 2R,4'R,8'R-alpha-tocopherol. Thus, compounds have been prepared that allow the investigation of the rate of alpha-TTP-mediated inter-membrane transfer of alpha-tocopherol and to investigate the mechanism of alpha-TTP function at membranes of different composition.     

Identification of an achiral analogue of J-113397 as potent nociceptin/orphanin FQ receptor antagonist

To date, J-113397 represents the most potent and selective non peptide NOP receptor antagonist widely used in pharmacological studies. However, the synthesis, purification, and enantiomer separation of this molecule, which contains two chiral centers, is rather difficult and low-yielding. Here, we synthesized and tested a series of simplified J-113397 analogues to investigate the importance of the stereochemistry and the influence of the substituents at position 3 of the piperidine nucleus and on the nitrogen atom of the benzimidazolidinone nucleus. The compound coded as Trap-101, an achiral analogue of J-113397, combines a pharmacological profile similar to that of the parent compound with a practical, high-yielding preparation.     

Synthesis and in vivo evaluation of [11C]SN003 as a PET ligand for CRF1 receptors

Synthesis and evaluation of [O-methyl-11C](4-methoxy-2-methylphenyl)[1-(1-methoxymethylpropyl)-6-methyl-1H-[1,2,3]triazolo[4,5-c]pyridin-4-yl]amine or [11C]SN003 ([11C]6), as a PET imaging agent for CRF1 receptors, in baboons is described. 4-[1-(1-Methoxymethylpropyl)-6-methyl-1H-[1,2,3]triazolo[4,5-c]pyridin-4-ylamino]-3-methylphenol (5), the precursor molecule for the radiolabeling, was synthesized from 2,4-dichloro-6-methyl-3-nitropyridine in seven steps with 20% overall yield. The total time required for the synthesis of [11C]SN003 is 30 min from EOB using [11C]methyl triflate in the presence of NaOH in acetone. The yield of the synthesis is 22% (EOS) with >99% chemical and radiochemical purities and a specific activity of >2000 Ci/mmol. PET studies in baboon show that [11C]6 penetrates the BBB and accumulates in brain. No detectable specific binding was observed, likely due to the rapid metabolism or low density of CRF1 receptors in primate brain.