Molecular models of NS3 protease variants of the Hepatitis C virus

Background  

Hepatitis C virus (HCV) currently infects approximately three percent of the world population. In view of the lack of vaccines against HCV, there is an urgent need for an efficient treatment of the disease by an effective antiviral drug. Rational drug design has not been the primary way for discovering major therapeutics. Nevertheless, there are reports of success in the development of inhibitor using a structure-based approach. One of the possible targets for drug development against HCV is the NS3 protease variants. Based on the three-dimensional structure of these variants we expect to identify new NS3 protease inhibitors. In order to speed up the modeling process all NS3 protease variant models were generated in a Beowulf cluster. The potential of the structural bioinformatics for development of new antiviral drugs is discussed.     

Study of response of Swiss Webster mice to light subunit of mushroom tyrosinase

The light subunit of mushroom, Agaricus bisporus, tyrosinase (LSMT), has been identified as an extrinsic component of the enzyme. Its function is unknown, but it can cross an epithelial cell layer, which suggests that it can be absorbed by the intestine. A similar capability has been demonstrated for the HA-33 component of the progenitor toxin from Clostridium botulinum, which is the closest structural homolog of LSMT. Unlike HA-33, LSMT appears to be non-immunogenic as shown by preliminary tests in Swiss Webster mice. We investigated the immunogenicity and histopathology of LSMT in mice to determine its safety in vivo. LSMT did not evoke generation of antibodies after prolonged periods of intraperitoneal administration. Histopathological observations confirmed the absence of responses in organs after twelve weekly administrations of LSMT. We found that LSMT is not toxic and is less immunogenic than the C. botulinum HA-33 protein, which supports further research and development for pharmaceutical application.     

Evidence for concerted movement of nuclear and mitochondrial clines in a lizard hybrid zone

Moving hybrid zones provide compelling examples of evolution in action, yet long‐term studies that test the assumptions of hybrid zone stability are rare. Using replicated transect samples collected over a 10‐year interval from 2002 to 2012, we find evidence for concerted movement of genetic clines in a plateau fence lizard hybrid zone (Sceloporus tristichus) in Arizona. Cline‐fitting analyses of SNP and mtDNA data both provide evidence that the hybrid zone shifted northward by approximately 2 km during the 10‐year interval. For each sampling period, the mtDNA cline centre is displaced from the SNP cline centre and maintaining an introgression distance of approximately 3 km. The northward expansion of juniper trees into the Little Colorado River Basin in the early 1900s provides a plausible mechanism for hybrid zone formation and movement, and a broadscale quantification of recent land cover change provides support for increased woody species encroachment at the southern end of the hybrid zone. However, population processes can also contribute to hybrid zone movement, and the current stability of the ecotone habitats in the centre of the hybrid zone suggests that movement could decelerate in the future.     

A Dutch guideline for the treatment of scoliosis in neuromuscular disorders

Background

Children with neuromuscular disorders with a progressive muscle weakness such as Duchenne Muscular Dystrophy and Spinal Muscular Atrophy frequently develop a progressive scoliosis. A severe scoliosis compromises respiratory function and makes sitting more difficult. Spinal surgery is considered the primary treatment option for correcting severe scoliosis in neuromuscular disorders. Surgery in this population requires a multidisciplinary approach, careful planning, dedicated surgical procedures, and specialized after care.

Methods

The guideline is based on scientific evidence and expert opinions. A multidisciplinary working group representing experts from all relevant specialties performed the research. A literature search was conducted to collect scientific evidence in answer to specific questions posed by the working group. Literature was classified according to the level of evidence.

Results

For most aspects of the treatment scientific evidence is scarce and only low level cohort studies were found. Nevertheless, a high degree of consensus was reached about the management of patients with scoliosis in neuromuscular disorders. This was translated into a set of recommendations, which are now officially accepted as a general guideline in the Netherlands.

Conclusion

In order to optimize the treatment for scoliosis in neuromuscular disorders a Dutch guideline has been composed. This evidence-based, multidisciplinary guideline addresses conservative treatment, the preoperative, perioperative, and postoperative care of scoliosis in neuromuscular disorders.     

Differences in activity of hepatic microsomal triglyceride transfer protein among species

Five sows, five cows, five hens, six guinea pigs, six rabbits, and six rats were used in a study to determine if hepatic microsomal triglyceride transfer protein activity differed among species that varied in site of fatty acid synthesis and rate of hepatic triglyceride export. No differences in plasma nonesterified fatty acids were seen among species. Plasma concentrations of glucose were highest in the hen, intermediate in the rat, guinea pig, and rabbit and lowest in the sow and cow. Liver triglyceride was low in all species with the only significant difference being between the hen and the guinea pig (4.7 and 1.1%, DM basis, respectively). No microsomal triglyceride transfer protein activity was found in muscle. The cow, rat, and guinea pig had the lowest levels and the hen and rabbit the highest levels of duodenal microsomal triglyceride transfer protein activity. Hepatic microsomal triglyceride transfer protein activity was significantly higher in the sow than the other species. Hepatic microsomal triglyceride transfer protein activity was 1.51, 1.63, 2.36, 2.72, 2.95, and 6.70 nmole triolein transferred/h/mg microsomal protein for the guinea pig, rabbit, cow, rat, hen, and sow, respectively. Microsomal triglyceride transfer protein activity in duodenal tissue was 18.0, 18.6, 19.2, 33.4, 113, and 161% of hepatic microsomal triglyceride transfer protein activity for the sow, cow, rat, guinea pig, hen, and rabbit, respectively. Hepatic microsomal triglyceride transfer protein activity scaled to liver weight and metabolic body size was 2.69, 3.36, 4.58, 5.83, 7.49, and 22.3 nmole triolein transferred in the liver/min/kg body weight0.75 for the rabbit, guinea pig, rat, hen, cow, and sow, respectively. There was little relationship between previously published rates for triglyceride export and hepatic microsomal triglyceride transfer protein activity measured in this experiment.     

Strategies to improve fertility of high yielding dairy farms: Management of the dry period

Reproductive performance of dairy cattle has been related to a wide variety of indicators of energy status, e.g., extent of negative energy balance, time of energy balance nadir, body weight loss, body condition score, and body condition score loss. Energy balance begins to decrease during the last few weeks prior to calving primarily due to a 30-35% reduction in feed intake. Cows typically remain in negative energy balance for five to seven weeks postpartum. Nutritional strategies to improve energy balance during the transition period include fat supplementation and feeding additional nonfiber carbohydrate. Unfortunately, neither approach is likely to markedly enhance energy status, although fat supplementation may increase reproductive efficiency independent of any effect on energy balance. Alternative management strategies may be required to improve fertility of dairy cows. Shortening or eliminating the dry period may improve energy status of dairy cows and increase reproductive efficiency. Shortening or eliminating the dry period may enhance dry matter intake during the transition period, decrease milk energy output, or both. A preliminary study using small animal numbers indicated that reducing dry period length to 28 or 0 days may decreases days to first ovulation, increase first service conception rate, and decrease days open. A follow-up study employing large animal numbers confirmed that reducing dry period length from 55 to 34 days can decrease days to first ovulation and decrease the percentage of anovular cows. The reduction in days open was greater for older cows than second parity cows. The reduction in days open was not related to effects of treatment on milk yield. Shortening or eliminating the dry period may be a more successful approach to improving reproductive efficiency than diet manipulation.     

Mesencephalic dopaminergic neurons express a repertoire of olfactory receptors and respond to odorant-like molecules

Background

The mesencephalic dopaminergic (mDA) cell system is composed of two major groups of projecting cells in the Substantia Nigra (SN) (A9 neurons) and the Ventral Tegmental Area (VTA) (A10 cells). Selective degeneration of A9 neurons occurs in Parkinson’s disease (PD) while abnormal function of A10 cells has been linked to schizophrenia, attention deficit and addiction. The molecular basis that underlies selective vulnerability of A9 and A10 neurons is presently unknown.

Results

By taking advantage of transgenic labeling, laser capture microdissection coupled to nano Cap-Analysis of Gene Expression (nanoCAGE) technology on isolated A9 and A10 cells, we found that a subset of Olfactory Receptors (OR)s is expressed in mDA neurons. Gene expression analysis was integrated with the FANTOM5 Helicos CAGE sequencing datasets, showing the presence of these ORs in selected tissues and brain areas outside of the olfactory epithelium. OR expression in the mesencephalon was validated by RT-PCR and in situ hybridization. By screening 16 potential ligands on 5 mDA ORs recombinantly expressed in an heterologous in vitro system, we identified carvone enantiomers as agonists at Olfr287 and able to evoke an intracellular Ca²⁺ increase in solitary mDA neurons. ORs were found expressed in human SN and down-regulated in PD post mortem brains.

Conclusions

Our study indicates that mDA neurons express ORs and respond to odor-like molecules providing new opportunities for pharmacological intervention in disease.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-729) contains supplementary material, which is available to authorized users.     

In vitro assessment of some sperm function following exposure to levonorgestrel in human fallopian tubes

Background  

The mechanism of action of levonorgestrel (LNG) as emergency contraception (EC) remains a subject of debate and its effect on sperm function has been only partially explained. The aim of this study was to assess whether LNG at a similar dose to those found in serum following oral intake for EC could affect spermatozoa when exposed to human fallopian tubes in vitro.