Molecular basis for PICS-mediated piRNA biogenesis and cell division

By incorporating two mutually exclusive factors, PID-1 and TOST-1, C. elegans PICS complex plays important roles in piRNA biogenesis, chromosome segregation and cell division. We firstly map the interaction network between PICS subunits, then uncover the mechanisms underlying the interactions between PICS subunits by solving several complex structures, including those of TOFU-6/PICS-1, ERH-2/PICS-1, and ERH-2/TOST-1. Our biochemical experiment also demonstrates that PICS exists as an octamer consisting of two copies of each subunit. Combining structural analyses with mutagenesis experiments, we identify interfacial residues of PICS subunits that are critical for maintaining intact PICS complex in vitro. Furthermore, using genetics, cell biology and imaging experiments, we find that those mutants impairing the in vitro interaction network within PICS, also lead to dysfunction of PICS in vivo, including mislocalization of PICS, and reduced levels of piRNAs or aberrant chromosome segregation and cell division. Therefore, our work provides structural insights into understanding the PICS-mediated piRNA biogenesis and cell division.

Molecular Logic Gate Based on DNA Strand Displacement Reaction

In this paper, I construct an XOR logic gate based on DNA strand displacement reaction, and verify our design through corresponding biochemical experiment. I designed several different DNA strands. Based on two basic DNA strand displacement reaction mechanisms, by adding different input strands and taking the signal of FAM fluorescent group as the output, the XOR logic gate is realized. The result shows that DNA strand displacement technology has important application value in DNA computing, especially in the construction of DNA molecular logic gates.

Molecular basis for PICS-mediated piRNA biogenesis and cell division

By incorporating two mutually exclusive factors, PID-1 and TOST-1, C. elegans PICS complex plays important roles in piRNA biogenesis, chromosome segregation and cell division, respectively. We firstly mapped the interaction network between PICS subunits. By solving the several complex structures, including those of TOFU-6/PICS-1, ERH-2/PICS-1, and ERH-2/TOST-1, we uncover the mechanisms underlying the interactions between PICS subunits. Our biochemical experiment demonstrates that PICS exists as an octamer consisting of two copies of each subunits. Combining structural analyses with mutagenesis experiments, we identified residues of PICS subunits that are critical for maintaining intact PICS complex in vitro. Furthermore, using genetics, cell biology and imaging experiments, we found that those mutants impairing the in vitro interaction network within PICS, also lead to abnormal dysfunction PICS in vivo, including mislocalization of PICS, and reduced levels of piRNAs or abnormal chromosome segregation and cell division. Therefore, our work provides structural insights into understanding the PICS-mediated piRNA biogenesis and cell division.

Study on Screening Microorganisms with Resistance to Parathion-Methyl and Degradation Characteristics

Toxicity of organophosphorus pesticide and the use of non-standard, which was the main factor of soil pesticides pollution, directly or indirectly harm human health. This study screened three wild species of bacteria, from the soil contaminated by pesticides in long-term, and respectively name as A1, A2 and A3. According to the bacterial 16S rDNA gene sequence analysis, combining with bacterial morphology, physiological and biochemical experiment results, and referring to "Berger bacterial identification manuals (eighth edition)", identified the three strains as Bacillus Branch, Clostridium microorganisms. A1, A2 and A3 were respectively Bacillus pasteurii, Clostridium butyricum and Clostridium acetobutylicum. Through the strain’s degradation and tolerability experiment to parathion-methyl, it turned out that the three strains reached the highest degradation rate in 12h, which was 73.04%, 78.05% and 85.51%, respectively.

AUTOMATIC SELECTION OF TWO-DIMENSIONAL ELECTROPHORESIS GEL WITH LEAST GEOMETRIC DISTORTIONS

The paper presents an algorithm for automated selection of the highest quality two-dimensional gel electrophoresis image. The quality criterion is the amount of vertical geometric distortions of the gel. The aim is to select the least distorted gel from the group received during the same biochemical experiment. Vertical geometric distortions displace proteins of the same molecular mass from the horizontal line and have a greater impact on the determination of protein characteristics than horizontal distortions. After presenting algorithm for evaluation of distortions and selection of base gel results are compared to expert's made selections. If necessary, algorithm may be adapted for horizontal distortion evaluation.