The EGL-13 SOX domain transcription factor affects the uterine pi cell lineages in Caenorhabditis elegans

We isolated egl-13 mutants in which the pi cells of the Caenorhabditis elegans uterus initially appeared to develop normally but then underwent an extra round of cell division. The data suggest that egl-13 is required for maintenance of the pi cell fate.     

Structure-based prediction of potential binding and nonbinding peptides to HIV-1 protease

HIV-1 protease is a major drug target against AIDS as it permits viral maturation by processing the gag and pol polyproteins of the virus. The cleavage sites in these polyproteins do not have obvious sequence homology or a binding motif and the specificity of the protease is not easily determined. We used various threading approaches, together with the crystal structures of substrate complexes which served as template structures, to study the substrate specificity of HIV-1 protease with the aim of obtaining a better differentiation between binding and nonbinding sequences. The predictions from threading improved when distance-dependent interaction energy functions were used instead of contact matrices. To rank the peptides and properly account for the peptide's conformation in the total energy, the results from using short-range potentials on multiple template structures were averaged. Finally, a dynamic threading approach is introduced which is potentially useful for cases when there is only one template structure available. The conformational energy of the peptide-especially the term accounting for the side chains-was found to be important in differentiating between binding and nonbinding sequences. Hence, the substrate specificity, and thus the ability of the virus to mature, is affected by the compatibility of the substrate peptide to fit within the limited conformational space of the active site groove.     

Fertility in barley flowers depends on Jekyll functions in male and female sporophytes

? Owing to its evolutional plasticity and adaptability, barley (Hordeum vulgare) is one of the most widespread crops in the world. Despite this evolutionary success, sexual reproduction of small grain cereals is poorly investigated, making discovery of novel genes and functions a challenging priority. Barley gene Jekyll appears to be a key player in grain development; however, its role in flowers has remained unknown. ? Here, we studied RNAi lines of barley, where Jekyll expression was repressed to different extents. The impact of Jekyll on flower development was evaluated based on differential gene expression analysis applied to anthers and gynoecia of wildtype and transgenic plants, as well as using isotope labeling experiments, hormone analysis, immunogold- and TUNEL-assays and in situ hybridization. ? Jekyll is expressed in nurse tissues mediating gametophyte-sporophyte interaction in anthers and gynoecia, where JEKYLL was found within the intracellular membranes. The repression of Jekyll impaired pollen maturation, anther dehiscence and induced a significant loss of fertility. The presence of JEKYLL on the pollen surface also hints at possible involvement in the fertilization process. ? We conclude that the role of Jekyll in cereal sexual reproduction is clearly much broader than has been hitherto realized.     

Investigation and analysis of a human orf outbreak among people living on the same farm

Human orf is a viral zoonotic infection caused by Parapoxvirus. The skin lesions of human orf can be misdiagnosed as cutaneous anthrax leading to overtreatment and also fear. This study was conducted to analyze an outbreak which led to deaths among kids and lambs in the same flock, and skin lesions in some persons who were living on the same farm that were initially diagnosed as cutaneous anthrax by a practitioner. Eight patients with skin lesions and eleven persons who had no skin lesion were considered as patients and control groups, respectively. The cultures obtained from the lesions of all patients were negative for Bacillus anthracis. The diagnosis of skin lesions was done by clinical findings, histopathological examination and PCR as human orf. To be under 20 years of age, direct contact with the animals, and contact with flayed skin of sick animals were the risk factors for human orf (Odds Ratio 7.5; 95% Confidence Interval 1.02-54.54, OR 12.25; 95% CI:1.3-100.9, OR 16.67; 95% CI:1.65-148.20, respectively). Orf should be kept in mind in the differential diagnosis of skin lesions resembling anthrax. For control and prevention of orf, transmission routes should be known; good hand hygiene and other personal protective measures have to be implemented.     

microRNAs – kleine Moleküle ganz groß

microRNAs, regulators of complex phenotypes microRNAs (miRNAs) are small, non‐coding RNAs that regulate a number of biological processes, including development. Due to their mode of action some miRNAs are also causally involved in diseases like cancer. miRNAs bind base‐complementary mRNAs and lead to either degradation of the bound mRNAs or translational repression. Both result in decreased protein levels of the particular target. miRNA selectivity is governed via a very short, just six to seven nucleotides long, ”seed" sequence which is likely to exist in many mRNAs. miRNAs are, therefore, believed to target a larger number of mRNAs, each, leading to the concerted regulation of functionally connected proteins and to thus substantially contribute to phenotypes. We have performed several screenings which suggest that, indeed, many miRNAs regulate a larger number of proteins. However, we also showed that the proteins we tested were regulated by a larger number of miRNAs each. The complexity of miRNA regulation opens new avenues towards reaching a molecular understanding of disease phenotypes via the integrated consideration of coordinated regulations.     

The Complete Mitochondrial Genome of the Foodborne Parasitic Pathogen Cyclospora cayetanensis

Cyclospora cayetanensis is a human-specific coccidian parasite responsible for several food and water-related outbreaks around the world, including the most recent ones involving over 900 persons in 2013 and 2014 outbreaks in the USA. Multicopy organellar DNA such as mitochondrion genomes have been particularly informative for detection and genetic traceback analysis in other parasites. We sequenced the C. cayetanensis genomic DNA obtained from stool samples from patients infected with Cyclospora in Nepal using the Illumina MiSeq platform. By bioinformatically filtering out the metagenomic reads of non-coccidian origin sequences and concentrating the reads by targeted alignment, we were able to obtain contigs containing Eimeria-like mitochondrial, apicoplastic and some chromosomal genomic fragments. A mitochondrial genomic sequence was assembled and confirmed by cloning and sequencing targeted PCR products amplified from Cyclospora DNA using primers based on our draft assembly sequence. The results show that the C. cayetanensis mitochondrion genome is 6274 bp in length, with 33% GC content, and likely exists in concatemeric arrays as in Eimeria mitochondrial genomes. Phylogenetic analysis of the C. cayetanensis mitochondrial genome places this organism in a tight cluster with Eimeria species. The mitochondrial genome of C. cayetanensis contains three protein coding genes, cytochrome (cytb), cytochrome C oxidase subunit 1 (cox1), and cytochrome C oxidase subunit 3 (cox3), in addition to 14 large subunit (LSU) and nine small subunit (SSU) fragmented rRNA genes.     

Construction of P-glycoprotein incorporated tethered lipid bilayer membranes

To investigate drug–membrane protein interactions, an artificial tethered lipid bilayer system was constructed for the functional integration of membrane proteins with large extra-membrane domains such as multi-drug resistance protein 1 (MDR1). In this study, a modified lipid (i.e., 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino (polyethylene glycol)-2000] (DSPE-PEG)) was utilized as a spacer molecule to elevate lipid membrane from the sensor surface and generate a reservoir underneath. Concentration of DSPE-PEG molecule significantly affected the liposome binding/spreading and lipid bilayer formation, and 0.03 mg/mL of DSPE-PEG provided optimum conditions for membrane protein integration. Further, the incorporation of MDR1 increased the local rigidity on the platform. Antibody binding studies showed the functional integration of MDR1 protein into lipid bilayer platform. The platform allowed to follow MDR!-statin-based drug interactions in vitro. Each binding event and lipid bilayer formation was monitored in real-time using Surface Plasmon Resonance and Quartz Crystal Microbalance–Dissipation systems, and Atomic Force Microscopy was used for visualization experiments.