A Type Ib Crustin from Deep-Sea Shrimp Possesses Antimicrobial and Immunomodulatory Activity.

Crustins are small antimicrobial proteins produced by crustaceans. Of the many reported crustins, very few are from deep sea environments. Crustins are categorized into several types. Recently, the Type I crustin has been further classified into three subtypes, one of which is Type Ib, whose function is unknown. Here, we studied the function of a Type Ib crustin (designated Crus2) identified from a deep-sea crustacean. Crus2 has a whey acidic protein (WAP) domain and a long C-terminal region (named P58). Recombinant Crus2 bound to peptidoglycan (PGN), lipoteichoic acid (LTA), and lipopolysaccharide (LPS), and killed Gram-positive and Gram-negative bacteria by permeabilizing the bacterial cytomembrane. Consistently, Crus2 dramatically attenuated the inflammatory response induced by LPS and LTA. Disruption of the disulfide bonds in the WAP domain abolished the bactericidal ability of Crus2, but had no effect on the bacterial binding ability of Crus2. Deletion of the C-terminal P58 region moderately affected the antimicrobial activity of Crus2 against some bacteria. P58 as a synthesized peptide could bind bacteria and inhibit the bactericidal activity of Crus2. Taken together, these results revealed different roles played by the WAP domain and the P58 region in Type Ib crustin, and provided new insights into the antimicrobial and immunomodulatory functions of crustins.

Induction and Monitoring of DNA Phase Separation in Living Cells by a Light-Switching Ruthenium Complex.

Phase separation of DNA is involved in chromatin packing for the regulation of gene transcription. Visualization and manipulation of DNA phase separation in living cells present great challenges. Herein, we present a Ru(II) complex (Ru1) with high DNA binding affinity and DNA "light-switch" behavior that can induce and monitor DNA phase separation both in vitro and in living cells. Molecular dynamics simulations indicate that the two phen-PPh3 ligands with positively charged lipophilic triphenylphosphine substituents and flexible long alkyl chains in Ru1 play essential roles in the formation of multivalent binding forces between DNA molecules to induce DNA phase separation. Importantly, the unique environmental sensitive emission property of Ru1 enables direct visualization of the dynamic process of DNA phase separation in living cells by two-photon phosphorescent lifetime imaging. Moreover, Ru1 can change the gene expression pattern by modulating chromatin accessibility as demonstrated by integrating RNA-sequencing and transposase-accessible chromatin with high-throughput sequencing. In all, we present here the first small-molecule-based tracer and modulator of DNA phase separation in living cells and elucidate its impact on the chromatin state and transcriptome.

Structure and plasticity of silent synapses in developing hippocampal neurons visualized by super-resolution imaging.

Excitatory synapses in the mammalian brain exhibit diverse functional properties in transmission and plasticity. Directly visualizing the structural correlates of such functional heterogeneity is often hindered by the diffraction-limited resolution of conventional optical imaging techniques. Here, we used super-resolution stochastic optical reconstruction microscopy (STORM) to resolve structurally distinct excitatory synapses formed on dendritic shafts and spines. The majority of these shaft synapses contained N-methyl-d-aspartate receptors (NMDARs) but not α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), suggesting that they were functionally silent. During development, as more spine synapses formed with increasing sizes and expression of AMPARs and NMDARs, shaft synapses exhibited moderate reduction in density with largely unchanged sizes and receptor expression. Furthermore, upon glycine stimulation to induce chemical long-term potentiation (cLTP), the previously silent shaft synapses became functional shaft synapses by recruiting more AMPARs than did spine synapses. Thus, silent shaft synapse may represent a synaptic state in developing neurons with enhanced capacity of activity-dependent potentiation.

Si-Bridged Ladder-Type Small-Molecule Acceptors for High-Performance Organic Photovoltaics.

In this study, we synthesized 5,11-dihexyl-4,4,10,10-tetraoctylbenzo[1,2- b:4,5- b']bisthieno[4″,5″- b″:4‴,5‴- b‴]silolo[2″,3″- d:2‴,3‴- d']thiophene (ArSi) as a ladder-type electron-rich core for the preparation of three acceptor-donor-acceptor-type nonfullerene acceptors (NFAs)-ArSiID, ArSiID-F, and ArSiID-Cl-featuring (3-oxo-2,3-dihydro-1 H-inden-1-ylidene)malononitrile (ID), 2-(5,6-difluoro-3-oxo-2,3-dihydro-1 H-inden-1-ylidene)malononitrile (ID-F), and 2-(5,6-dichloro-3-oxo-2,3-dihydro-1 H-inden-1-ylidene)malononitrile (ID-Cl) as peripheral electron-poor units, respectively. These molecules exhibit strong absorption covering the region of 600-850 nm. The incorporation of the halogen atoms onto the terminal units adjusted the energy levels and light-harvesting ability of these materials. We employed the conjugated polymers J51 and PBDB-T, having middle optical energy gaps as donor together with these ArSi derivatives as acceptor to study the blend film morphology and the corresponding organic photovoltaic (OPV) performances. After optimization with device engineering works, a PBDB-T:ArSiID-F-based device with a power conversion efficiency up to 9.4% was achieved. This study is the first case to examine the effects of various halogen modifications on the performance of ArSi derivatives that serve as NFAs for OPVs. Our findings should encourage further investigations on this rarely studied core structure for optoelectronic applications.

Y chromosome interstitial deletion induced Y-STR allele dropout in AMELY-negative individuals.

Short tandem repeat (STR) multiplexes with the amelogenin (AMEL) gene as a gender marker have been used as a routine tool of forensic DNA analysis. It has been reported that AMEL-based gender detection could misidentify a known male as a female due to the dropout of amelogenin Y (AMELY) allele. Other gender markers, such as Y-chromosomal short tandem repeat (Y-STR), may be a substitution of AMEL and help the sex determination. In current study, employing AmpFlSTR® Sinofiler and AmpFlSTR® Y-filer™ PCR Amplification kit, 18 AMELY-negative males were identified. Accordingly, the incidence of the AMELY dropout was 0.227 ‰ (18/79,304) in Chinese population. Sequencing of AMELY allele and analyzing of azoospermia factors region suggested that 3 out of 18 misidentifications were induced by mutations in the primer-binding region of the AMELY, while other 15 sex misidentifications were results of Y chromosome microdeletions with variant lengths. Moreover, variant combination patterns of AMELY dropout and Y-STRs deletions were also observed. Our data suggested that Y-STR locus dropout may indicate more problems, especially in the mixed sample's interpretation. Results of haplogroup prediction showed that seven AMELY dropouts combined with variant Y-STR deletions can be classified as the J2 subdivision, suggesting that some of these Y chromosomes might descend from a common ancestor.

A Y-chromosomal haplotype with two short tandem repeat mutations.

The male-specific Y-chromosomal short tandem repeat (STR) is a useful tool in forensic casework. The Y haplotype comprised of 16 loci, which is amplified simultaneously by AmpFlSTR(®) Yfiler(TM) PCR kit and provides strong exculpatory evidence in individual identification. We reported a rare Y-STR profile with a null allele at the DYS448 locus and an off-ladder allele at the DYS456 locus, when genotyping material from a vaginal swab in an alleged rape case. Sequence analysis revealed that the DYS448 null allele was a true type of null allele because of a total deletion of 11 upstream repeats and 9bp of the N(42) region, and there were numerous primer binding site mutations as well. The amplicon of the DYS456 locus was a small 92-bp fragment that was off-ladder, and sequencing analysis showed that there were only 10 repeats (AGAT)(10). This Y chromosome haplotype that was comprised of two variations provided helpful evidence for personal identification.

[Study on immobilization of Acidithiobacillus ferrooxidans using PVA-Ca(NO3)2 method].

A new cell immobilization technique utilizing the complex of PVA solution and sodium alginate solution as entrapment medium is reported. The mixture of Acidithiobacillus ferrooxidans suspension and the entrapment complex were extruded into the solution of Ca(NO3)2 (1% - 5%) to form beads, then the beads were frozen at -20 degrees C for 1d and thawed at room temperature. This method can simultaneously eliminate the agglomeration of PVA beads and the biological toxicity of H3 BO31. A maximum oxidation rate of 2.45g Fe2+ /(L x h) was achieved in batch cultures by this immobilized cells. In addition, the operation of this new technique is very simple, and the gelation solution (calcium nitrate) used is of low toxicity and very cheap. Moreover, the mechanical strength and the oxidation activity of the beads obtained by this technique are better than those obtained by the other methods. So its application on an industrial scale would be more practicable.