The TRIM-NHL protein LIN-41 controls the onset of developmental plasticity in Caenorhabditis elegans.

The mechanisms controlling cell fate determination and reprogramming are fundamental for development. A profound reprogramming, allowing the production of pluripotent cells in early embryos, takes place during the oocyte-to-embryo transition. To understand how the oocyte reprogramming potential is controlled, we sought Caenorhabditis elegans mutants in which embryonic transcription is initiated precociously in germ cells. This screen identified LIN-41, a TRIM-NHL protein and a component of the somatic heterochronic pathway, as a temporal regulator of pluripotency in the germline. We found that LIN-41 is expressed in the cytoplasm of developing oocytes, which, in lin-41 mutants, acquire pluripotent characteristics of embryonic cells and form teratomas. To understand LIN-41 function in the germline, we conducted structure-function studies. In contrast to other TRIM-NHL proteins, we found that LIN-41 is unlikely to function as an E3 ubiquitin ligase. Similar to other TRIM-NHL proteins, the somatic function of LIN-41 is thought to involve mRNA regulation. Surprisingly, we found that mutations predicted to disrupt the association of LIN-41 with mRNA, which otherwise compromise LIN-41 function in the heterochronic pathway in the soma, have only minor effects in the germline. Similarly, LIN-41-mediated repression of a key somatic mRNA target is dispensable for the germline function. Thus, LIN-41 appears to function in the germline and the soma via different molecular mechanisms. These studies provide the first insight into the mechanism inhibiting the onset of embryonic differentiation in developing oocytes, which is required to ensure a successful transition between generations.

SAS-1 is a C2 domain protein critical for centriole integrity in C. elegans.

Centrioles are microtubule-based organelles important for the formation of cilia, flagella and centrosomes. Despite progress in understanding the underlying assembly mechanisms, how centriole integrity is ensured is incompletely understood, including in sperm cells, where such integrity is particularly critical. We identified C. elegans sas-1 in a genetic screen as a locus required for bipolar spindle assembly in the early embryo. Our analysis reveals that sperm-derived sas-1 mutant centrioles lose their integrity shortly after fertilization, and that a related defect occurs when maternal sas-1 function is lacking. We establish that sas-1 encodes a C2 domain containing protein that localizes to centrioles in C. elegans, and which can bind and stabilize microtubules when expressed in human cells. Moreover, we uncover that SAS-1 is related to C2CD3, a protein required for complete centriole formation in human cells and affected in a type of oral-facial-digital (OFD) syndrome.

Cytocompatibility testing of cyclodextrin-functionalized antimicrobial textiles-a comprehensive approach.

Functionalized textiles can be used in wound management to reduce the microbial burden in the wound area, to prevent wound infections, and to avoid cross-contamination between patients. In the present study, a comprehensive in vitro approach to enable the assessment of antibacterial activity of functionalized textiles and cytotoxicity of cyclodextrin (CD)-complexes with chlorhexidine diacetate (CHX), iodine (IOD), and polihexanide (PHMB) is suggested to evaluate their properties for supporting optimal conditions for wound healing. For all ß-CD-antiseptic functionalized cotton samples a strong antibacterial effect on the Gram-positive bacteria Staphylococcus aureus and Staphylococcus epidermidis as well as on the Gram-negative bacteria Klebsiella pneumoniae and Escherichia coli was proven. In addition, ß-CD-CHX and ß-CD-PHMB were effective against the yeast Candida albicans. The growth of Pseudomonas aeruginosa could be reduced significantly by ß-CD-IOD and ß-CD-PHMB. The established comprehensive testing system for determination of biocompatibility on human HaCaT keratinocytes is suitable for obtaining robust data on cell viability, cytotoxicity and mode of cell death of the ß-CD-antiseptic-complexes. The promising results of the high antimicrobial activity of these functionalized textiles show the high potential of such materials in medical applications.

6-Deoxy-6-aminoethyleneamino cellulose: synthesis and study of hemocompatibility.

Hemocompatibility of aqueous solutions of antimicrobial 6-deoxy-6-aminoethyleneamino (AEA) cellulose with different degrees of substitution (DS, 0.54-0.92) was investigated in vitro. The AEA cellulose derivatives were synthesized by tosylation of cellulose and subsequent nucleophilic substitution with 1,2-diaminoethane. The structure was confirmed by elemental analysis as well as by FTIR and NMR spectroscopies. Markers for coagulation (thrombin generation, aPTT, PT, blood clotting, thrombocyte activation) and membrane integrity (hemolysis) were measured in human whole blood, human platelet-rich plasma, human pooled plasma, and erythrocytes suspension. AEA cellulose with a low DS of 0.54 showed the highest hemocompatibility in vitro, suggesting the possibility of biomedical applications.

Antibacterial properties of cyclodextrin-antiseptics-complexes determined by microplate laser nephelometry and ATP bioluminescence assay.

Cyclodextrins (CDs) are able to form inclusion complexes with other molecules, thereby, protecting these guest molecules from degradation, enhancing their biocompatibility or influencing their physiological distribution while retaining their activity. Here, antibacterial effects of CD-complexes with the antiseptics chlorhexidine diacetate (CHX), iodine (IOD) and polihexanide (PHMB) were determined using two different in vitro methods, microplate laser nephelometry and an ATP bioluminescence assay. Laser nephelometry is a direct method for monitoring and evaluating growth of micro-organisms by measurement of the turbidity of the solution. In contrast, the ATP bioluminescence assay determines specifically the amount of metabolic active bacterial cells. The antibacterial effects of CD-antiseptics-complexes were examined for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis and the results of both methods were compared in respect of calculated means of half maximal inhibitory concentrations (IC50) and statistical evaluated Pearson's correlation coefficients (r). It could be demonstrated that both methods showed a high comparability although they differ in the parameters tested. This study revealed that CD-complexes with CHX and PHMB were most effective against E. coli and the tested staphylococci. While CD-IOD-complexes obtained high activity against K. pneumoniae, P. aeruginosa was distinctly more resistant compared to the other bacteria.

Antimicrobial properties of cyclodextrin-antiseptics-complexes determined by microplate laser nephelometry and ATP bioluminescence assay.

Antimicrobial effects of substances can be determined with different methods that measure distinct parameters. Thus, a comparison of the results obtained can be difficult. In this study, two in vitro methods were employed to determine concentration and time dependent effects of cyclodextrin (CD)-complexes with the antiseptics chlorhexidine diacetate (CHX), iodine (IOD) and polihexanide (PHMB) on Candida albicans and Malassezia pachydermatis. Using both, microplate laser nephelometry and the ATP bioluminescence assay, it could be shown that CD-antiseptics-complexes tested exhibited significant antifungal effects with the exception of γ-CD-CHX in the case of C. albicans. Microplate laser nephelometry (MLN) is an optical method and enables a quantitative determination of particle concentrations in solution. By means of this method, microbial growth under influence of potential antimicrobial substances can be monitored over a prolonged time period. In addition, the antimicrobial activity was analyzed by measurement of the microbial adenosine triphosphate (ATP) content with a bioluminescent assay. The luminescent signal is directly proportional to the amount of ATP, and thus, a linear function of the number of living microbial cells present. Both methods were compared according to the half maximal inhibitory concentration (IC(50)) calculated and the statistical evaluation of Pearson's correlation coefficient (r). In summary, it could be demonstrated that both methods yield similar results although they differ in the parameter.