Optoelectronic properties of diathiafulvalene-functionalized diketopyrrolopyrrole-fullerene molecular dyad.

Single component molecular dyad donor-acceptor junction is an important type of organic solar cells. Understanding the optoelectronic properties of molecular dyad plays the critical role to develop active layer materials for such kind of solar cells. Here, diathiafulvalene-functionalized diketopyrrolopyrrole-fullerene (DFDPP-Ful) was selected as the representative system, and the geometries, electronic structures and excitation properties of DFDPP-Ful monomer and dimer were systematically investigated based on extensive quantum chemistry calculations. The transition configurations and molecular orbitals show that the effective electron donor and acceptor are DFDPP and fullerene moieties, respectively. It also found the light harvesting is dominated by local excitation in DFDPP moiety. Meanwhile, the hybridization and quasi-degeneration between charge transfer (CT) and local excitation exist. The dimer data suggest that the increased excited states contribute to the expanding of absorption spectra, and the excitations exhibit both the intermolecular and intra-molecular CTs. Also, the remarkable CT energy differences among the different dimer models for the lowest CT excited states support the strong interface and energy disorder in such system. Therefore, the suggestions for developing molecular dyad of single component organic solar cells would be the combination of increasing light absorption, enhancing CT and local excitation hybridization, as well as suppressing energy and interface disorder by the aid of molecular design.

Gut mucosal virome alterations in ulcerative colitis.

OBJECTIVE: The pathogenesis of UC relates to gut microbiota dysbiosis. We postulate that alterations in the viral community populating the intestinal mucosa play an important role in UC pathogenesis. This study aims to characterise the mucosal virome and their functions in health and UC. DESIGN: Deep metagenomics sequencing of virus-like particle preparations and bacterial 16S rRNA sequencing were performed on the rectal mucosa of 167 subjects from three different geographical regions in China (UC=91; healthy controls=76). Virome and bacteriome alterations in UC mucosa were assessed and correlated with patient metadata. We applied partition around medoids clustering algorithm and classified mucosa viral communities into two clusters, referred to as mucosal virome metacommunities 1 and 2. RESULTS: In UC, there was an expansion of mucosa viruses, particularly Caudovirales bacteriophages, and a decrease in mucosa Caudovirales diversity, richness and evenness compared with healthy controls. Altered mucosal virome correlated with intestinal inflammation. Interindividual dissimilarity between mucosal viromes was higher in UC than controls. Escherichia phage and Enterobacteria phage were more abundant in the mucosa of UC than controls. Compared with metacommunity 1, metacommunity 2 was predominated by UC subjects and displayed a significant loss of various viral species. Patients with UC showed substantial abrogation of diverse viral functions, whereas multiple viral functions, particularly functions of bacteriophages associated with host bacteria fitness and pathogenicity, were markedly enriched in UC mucosa. Intensive transkingdom correlations between mucosa viruses and bacteria were significantly depleted in UC. CONCLUSION: We demonstrated for the first time that UC is characterised by substantial alterations of the mucosa virobiota with functional distortion. Enrichment of Caudovirales bacteriophages, increased phage/bacteria virulence functions and loss of viral-bacterial correlations in the UC mucosa highlight that mucosal virome may play an important role in UC pathogenesis.

Protective effects of tacalcitol against oxidative damage in human epidermal melanocytes.

BACKGROUND: Oxidative damage may lead to the dysfunction of melanocytes (MCs) and is one of the causative mechanisms involved in the pathogenesis of vitiligo. OBJECTIVES: This study was designed to investigate the protective effects of the vitamin D3 analog tacalcitol on oxidative damage induced by hydrogen peroxide (H2 O2 ) in human epidermal MCs. METHODS: Human epidermal MCs were cultured and identified by l-DOPA staining and HMB-45 immunohistochemical staining. The model of oxidative damage induced by H2 O2 was established, and the cells were treated with tacalcitol. The viability of MCs was determined using an MTS assay. Morphological changes in cell dendrites were observed by microscopy, and the rate of change of dendrites was calculated. The reactive oxygen species (ROS) level in MCs was determined using immunofluorescence microscopy. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in MCs were determined using the WST-1 and TBA methods, respectively. RESULTS: In comparison with the control group, the viability of MCs and SOD activity were significantly decreased in the H2 O2 group (P < 0.05) and significantly increased in the tacalcitol group (P < 0.05). In comparison with the control group, the rate of change of cell dendrites and levels of ROS and MDA were significantly increased in the H2 O2 group (P < 0.05) and significantly decreased in the tacalcitol group (P < 0.05). CONCLUSIONS: Tacalcitol can reduce oxidative damage induced by H2 O2 in MCs by inhibiting intracellular ROS overproduction, increasing SOD activity, and decreasing the level of MDA, thereby reducing cell apoptosis.

[Effect of estrogen on mismatch repair gene expression in colon cancer cells].

AIM: To investigate the effect of estrogen on MMR gene expression in colon cancer cells COLO205. METHODS: By employing semi-quantitative RT-PCR and Western blotting techniques, changes in the expression of MMR genes (hMLH1 and hMSH2) induced by different levels of estradiol (E2) and ICI182.780, an estrogen receptor inhibitor, was investigated in cultured COLO205 cells. The effect was then verified by real time RT-PCR. RESULTS: E2 enhanced the expression of hMLH1 in COLO205 cells at transcriptional level, and a dose-response relationship was established when the concentration of E2 was between 10(-12);-10(-8); mol/L. The enhancement was suppressed by the estrogen receptor inhibitor ICI182.780. On the other hand, there was no significant effect of E2 on hMSH2 expression in COLO205 cells. CONCLUSION: E2 can increase the expression of hMLH1 in colon cancer cells COLO205, and this finding sheds new light on the mechanism of estrogen protecting against colon cancer by regulating MMR system.

[Expression of green fluorescent protein using an infectious cDNA clone of infectious bronchitis virus].

An infectious cDNA clone of H120 vaccine strain of infectious bronchitis virus (IBV) was constructed to demonstrate its potential as a gene transfer vector. Primers were designed according to the published genome sequence of H120 strain, and ten cDNA fragments covering the entire genome of H120 strain was amplified by RT-PCR. All the PCR products were ligated into pMD19-T vector and sequenced, and the ORF5a open reading frame in the pMDTM9 plasmid was replaced by an enhanced green fluorescent protein (EGFP) gene. Recombinant plasmids were digested by the restriction enzyme Bsa I, and all the cDNA fragments were recovered. By using appropriate ligation strategy, the genomic cDNA of H120 strain were reconstituted. Then genome RNA was synthesized in vitro by T7 RNA polymerase and transfected into BHK-21 cells. Recombinant virus expressing the green fluorescent protein was rescued and identified by RT-PCR and sequencing. The characteristics of recombinant virus were evaluated by passage in embryonated chicken eggs. This study showed that the 5a ORF is a good candidate for an insertion site of recombinant genes for the development of IBV infectious cDNA clone as a gene transfer vector.

Estrogen stimulates the expression of mismatch repair gene hMLH1 in colonic epithelial cells.

Estrogen is reported to have a protective effect on colon cancer; however, the underlying mechanism is unclear. Impaired mismatch repair plays an important role in colonic carcinogenesis. The purpose of this study was to investigate the association of estrogen on regulating mismatch repair expression in colonic epithelial cells. In cultured COLO205 cells, the effect of estradiol (E2) and antagonist ICI182.780 on the expression of hMLH1 and hMSH2 was studied using reverse transcription-PCR and Western blotting. The correlation between serum level E2 and the expression of hMLH1 and hMSH2 in colonic mucosal tissue of 42 healthy individuals was also examined using reverse transcription-PCR and immunohistochemical staining. E2 increased the expression of hMLH1 in COLO205 cells, which was suppressed by ICI182.780. However, the effect of E2 on hMSH2 expression was not significant in COLO205 cells. In healthy individuals, a strong positive correlation of E2 level with hMLH1 expression in normal colonic epithelial cell was observed when serum E2 level was >45 pg/mL, but no correlation was seen between E2 and hMSH2 expression. E2 affects the expression of hMLH1 but not hMSH2 in vitro, and high serum E2 level correlates with hMLH1 expression in vivo. These findings suggest that the anticolonic cancer effect of estrogen may be related to hMLH1 regulation.

[Construction of a retroviral vector carrying HBX gene and its expression in LO2 human hepatocytes].

OBJECTIVE: To construct a retroviral vector carrying HBX gene and investigate its expression in LO2 human hepatocytes. METHODS: HBX gene was amplified by PCR and subcloned into the retroviral vector pSEB-Flag to construct a retroviral plasmid (pSEB-Flag-HBX) expressing HBX. The HBX gene insert was confirmed by restriction enzyme digestion, PCR and DNA sequencing. The recombinant retroviruses carrying HBX gene were generated in 293T cells co-transfected with pSEB-Flag-HBX and the packaging plasmids pAmpho, and used to infect LO2 human hepatocyte. After selection with blasticidin, the mRNA and protein expressions of HBx were determined by the reverse transcription-PCR and Western blotting, respectively. RESULTS: The retroviral plasmid (pSEB-Flag-HBX) carrying HBX was constructed successfully. The recombinant retrovirus efficiently delivered HBX gene into LO2 human hepatocyte, resulting in stable expression of HBX mRNA and HBx protein as shown by RT-PCR and Western blotting, respectively. CONCLUSION: The recombinant retrovirus pSEB-Flag-HBX has been successfully constructed, which is capable of delivering the target gene HBX into LO2 human hepatocytes and results in stable expression of HBx to serve as an ideal model to study the effect of HBx on the development of hepatocellular carcinoma.

[Effect of vascular endothelial growth factor on pre-eclampsia in pregnant rats].

OBJECTIVE: To investigate relationship between the vascular endothelial growth factor (VEGF) and the pathogenesis of pre-eclampsia in pregnant rats. METHODS: Pregnant rats were divided into two groups randomly. Saline solution or L-nitro arginine methyl ester (L-NAME) 125 mg/d was given subcutaneously from day 7 of gestation till establishing pre-eclampsia. Systolic blood pressure, urine protein, platelet count, and weight of pups and placenta were determined. The levels of VEGF in pregnant rats venous serum, placenta and decidual tissue from normal pregnancy and pre-eclampsia rats were detected by ELISA and immunohistochemistry, respectively. RESULT: Pregnant rats which were given L-NAME produced physical signs similar to those of pre-eclampsia, such as increase in systolic blood pressure [(145.3 +/-4.6)mmHg] and urine protein [(814.3 +/-57.5)mg/L], and decrease in platelet count [(467.1 +/-76.3) x 10(9)/L] and weight of pups and placenta. Compared with controls, the intensity of VEGF immunostaining in trophoblast or decidual cells were significantly reduced. The serum levels of VEGF were significantly lower in pre-eclampsia group than in normal pregnancy. CONCLUSION: Decreased serum levels of VEGF and reduced expression of VEGF in placental tissues might in part explain the pathogenesis of pre-eclampsia in pregnant rats.