Use of bone mesenchymal stem cells to treat rats with acute liver failure

This study aimed to isolate mesenchymal stem cells from bone mesenchymal stem cells (BMSCs), determine their therapeutic potential for treating rats with acute liver failure (ALF), further explore the factors that induce liver failure mechanisms, and elucidate the role of bone marrow stem cell therapy and BMSCs on liver homing. We found that differentiation potential was present in BMSCs expressing high levels of CD29 and CD90. These cells improved liver functioning in vivo after transplantation into rat livers with D-galactosamine damage, as evidenced by the levels of alanine aminotransferase and aspartate aminotransferase returning to normal (low levels) in recipient ALF rats. A significant improvement in the liver functional test and histological findings was observed in the transplantation group after 120 and 168 h of transplantation (P < 0.05). Histological data revealed that hepatocyte cell apoptosis was lower in the transplantation group compared to the control groups (P < 0.05), and that the transplantation of BMSCs reduced liver inflammation, decreased hepatic denaturation and necrosis, and promoted liver regeneration. These ameliorations were not recorded in the control groups. The results of in situ hybridization, immunofluorescence staining, and Western blot confirmed the presence of transplanted BMSCs in recipient rat livers. Stromal cell derived factor-1 alpha and vascular endothelial growth factor were significantly upregulated after the intraportal transplantation of BMSCs, with significantly higher levels being found in the portal vein and the tail vein groups (P < 0.05). In conclusion, BMSCs have a therapeutic effect against ALF rats, evoke endogenous repair mechanisms in the liver, and may represent a novel form of therapeutic intervention for the disease. Furthermore, intraportal transplantation serves as a more effective pathway compared to tail vein transplantation.

Clinical characteristics and predictors of the duration of SARS-CoV-2 viral shedding in 140 healthcare workers

BACKGROUND

Epidemiological and clinical features of patients with COVID-19 have been reported, but none of them focused on medical staff, and few predictors of the duration of viral shedding have been reported. It is urgent to help healthcare workers prevent and recover quickly from the coronavirus disease 2019 (COVID-19).

METHODS

We enrolled 140 medical workers with COVID-19 in Wuhan. Epidemiological, demographic, clinical, laboratory, radiological treatment and clinical outcome data were collected, and predictors of the duration of viral shedding were explored through multivariable linear regression analysis.

RESULTS

The medical staff with COVID-19 presented mild clinical symptoms and showed a low frequency of abnormal laboratory indicators. All the medical staff were cured and discharged, of whom 96 (68.6%) were female, 39 (27.9%) had underlying diseases, the median age was 36.0 years, and 104 (74.3%) were infected whilst working in hospital. The median duration of viral shedding was 25.0 days (IQR:20.0-30.0). Multivariable linear regression analysis showed reducing viral shedding duration was associated with receiving recombinant human interferon alpha (rIFN-α) treatment, whilst the prolonged duration of viral shedding correlated with the use of glucocorticoid treatment, the durations from the first symptom to hospital admission and the improvement in chest computed tomography (CT) evidence. Moreover, infected healthcare workers with lymphocytes less than 1.1 × 10⁹ /L on admission had prolonged viral shedding.

CONCLUSION

Medical staff with timely medical interventions show milder clinical features. Glucocorticoid treatment and lymphocytes less than 1.1 × 109/L are associated with prolonged viral shedding. Early admission and rIFN-α treatment help shorten the duration of viral shedding.

GADD45A is a mediator of CD437 induced apoptosis in ovarian carcinoma cells

Ovarian cancer is one of the leading causes of cancer death in women. A number of studies have suggested that synthetic retinoids may play an important role as an ovarian cancer chemotherapeutic agent. The synthetic retinoid CD 437 induces apoptosis in ovarian tumor cells by a mechanism that is not completely understood. In this study we demonstrate that CD437 treatment leads to an increase in GADD45A and GADD45B mRNA expression in CA-OV3 cells but not in CA-CD437R cells, a cell line which is resistant to CD437. This induction is specific to CD437 since no change in expression of either GADD45A or GADD45B was observed with either all-trans-RA or 4-HPR treatment. Western blot analysis demonstrated that the induction of GADD45A mRNA in the CA-OV3 cell line by CD437 was accompanied by an increase in GADD45A protein. Upregulation of GADD45A by CD437 is regulated at least in part at the post-transcriptional level. In contrast, CD437 regulates GADD45B expression by different mechanisms. The importance of GADD45A induction in mediating apoptosis was demonstrated in CA-OV3 cells overexpressing GADD45A antisense RNA (GADD45A-AS cells). Our results suggest that induction of GADD45A expression might play a role in mediating the apoptotic response of ovarian cancer cells to the synthetic retinoid CD437.

Increased long noncoding RNA LINC00511 is correlated with poor prognosis and contributes to cell proliferation and metastasis by modulating miR-424 in hepatocellular carcinoma

OBJECTIVE

Long noncoding RNAs (lncRNAs) have been reported to be abnormally expressed in human hepatocellular carcinoma (HCC) and associated with the progression of HCC. LncRNA LINC00511 (LINC00511) has been confirmed to act as a tumor promoter in several tumors. However, as a novel lncRNA, the specific effect of LINC00511 is still largely obscure. In this study, we aimed to evaluate the effect of LINC00511 in HCC behaviors and to elucidate the mechanism by which this occurs.

PATIENTS AND METHODS

The expressions of LINC00511 in HCC tissues and cell lines were evaluated by qRT-PCR. The correlations between LINC00511 expression and the clinicopathological parameters and prognosis of HCC patients were determined using several statistical methods. CCK-8 assay, colony formation assay, flow cytometry cell cycle, apoptosis assay, EdU assay, wound healing assay, and transwell assay were used to investigate the role of LINC00511 on the malignant phenotypes in vitro. Insights into the potential mechanisms of ceRNAs were determined by bioinformatics analysis, dual-luciferase reporter assays and RT-PCR.

RESULTS

LINC00511 expression was significantly up-regulated in HCC tissues and cell lines, and its high expression was distinctly associated with nodal metastasis, vascular invasion, and clinical stage. Furthermore, statistical assays revealed that HCC patients with higher LINC00511 expression levels had worse overall survival rates. Importantly, the multivariate analysis confirmed that LINC00511 expression was an independent prognostic factor of the overall survival in patients with HCC. Functionally, the inhibition of LINC00511 significantly suppressed the capability of proliferation, migration, and invasion in HCC cell lines. Bioinformatic tools predicted that miR-424 both targeted the 3'-UTR of LINC00511, which was confirmed using the luciferase reporter assay and RT-PCR.

CONCLUSIONS

LINC00511 plays an important role in the malignant progression of HCC via modulation of miR-424.

Some properties of receptive fields of olfactory mitral/tufted cells in the frog

1. Different regions of the frog's olfactory epithelium were stimulated with nine glass micropipettes either individually or simultaneously in different combinations. The stimulus was a positive electrical pulse (4 s) consisting of a progressive increase, a plateau, and a progressive decrease in current intensity. Extra- and intracellular recordings were made from olfactory bulb mitral/tufted cells. Some of these cells were identified by intracellular injection of Lucifer yellow. 2. The action potential response patterns of mitral/tufted cells during the different phases of the stimulation were coded according to whether the activity was increased or decreased compared with its spontaneous level just before stimulation. Neural responses were classified into 11 types: individual neurons responded with different response types to stimuli delivered at different epithelial sites. On the basis of these response types, it was found that neurons could be classified into two groups. All response types in one group included an initial phase of increased discharge (excitation), whereas all types in the other group included an initial phase of decreased activity (suppression). Neurons that displayed response types belonging to one group never displayed those of the other group. It was thus concluded that a given neuron responded either always with an increased activity or always with a decreased activity, whatever the location of the stimulus. 3. The receptive field of a mitral/tufted cell appeared to be homogenous and not divided into areas of different properties, at least under the present experimental conditions. The extent of a receptive field was estimated by determining the number of effective epithelial sites (where an electrical stimulus evoked a response from a bulbar neuron).(ABSTRACT TRUNCATED AT 400 WORDS)

Functional consequences of acute collagen degradation studied in crystalloid perfused rat hearts

OBJECTIVES

The impact of acute collagen disruption by the disulfide donor, 5,5'-dithio-2-nitrobenzoic acid (DTNB) on ventricular properties was tested in rat hearts.

METHODS

Collagen was degraded acutely in 13 isolated, isovolumically contracting rat hearts by perfusion with 1 mM DTNB added to Krebs-Henseleit solution for 1 hour followed by 2-hour perfusion with normal solution. Another 13 hearts were perfused with normal solution for 3 hours (Control).

RESULTS

Collagen content was 3.5 +/- 0.5% of ventricular dry weight in control group compared with 2.1 +/- 0.4% in DTNB group (decrease by 40%, p < 0.01). Scanning electron micrographs revealed loss of the delicate collagen network surrounding muscle fibers in DTNB treated hearts. Developed pressure at a fixed volume decreased to 86 +/- 17% of the baseline value after 3-hour perfusion in the control group, whereas in DTNB treated hearts developed pressure fell to 68 +/- 13% (p < 0.01). End-diastolic pressure was set at 5 mmHg at the beginning of the experiment and rose to 15 +/- 8 mmHg in control and 30 +/- 13 mmHg (p < 0.01) in the treated hearts. Concomitantly, wet-to-dry weight ratio increased from 5.63 +/- 0.26 in control to 6.07 +/- 0.11 (p < 0.05) in the DTNB treated hearts. A separate set of experiments on isolated myocytes excluded the possibility of a direct effect of DTNB on myocyte contractile function.

CONCLUSIONS

These data suggested that with 40% collagen disruption by DTNB there is a significant increase in tissue edema that results in a decrease in chamber capacitance; in addition, there is a significant decrease in systolic performance which reflects the combined effect of edema and loss of collagen.

Clinical characteristics and treatments of patients with alpha-fetoprotein producing gastric carcinoma

Alpha-fetoprotein (AFP) is a well-known tumor marker of hepatic carcinoma and yolk sac tumor. Alpha-fetoprotein producing gastric carcinoma (AFPGC) is a rare type of gastric cancer with high malignancy and poor prognosis, which make it different from other types of gastric cancer. This rare gastric cancer patient subgroup is likely frequently misdiagnosed which may be related to lack of knowledge of the disease. The purpose of this article is to summarize the mechanism of AFP positive gastric cancer, classification, biological behavior and treatment, in order to assist clinical practitioners to detect AFPGC earlier and treat it better. Previous studies have showed that AFPGC has a complex pathophysiology mechanism. AFPGC is more aggressive and characterized by stronger proliferation, neovascularization, lymphatic invasion and distant metastasis. Furthermore, so far there has been no standard treatment for patients with AFPGC. Nevertheless, our present study summarizes some effective treatments based on previous research outcome. In conclusion, the present study demonstrates that the importance of detecting AFP routinely in serum and tissues in gastric cancer cases, which will greatly improve the diagnosis rate of AFPGC, and in regards to treatment, surgery, chemotherapy, targeted therapy and interventional treatment may have positive impacts on AFPGC treatment outcome. However, further study with a larger sample is required to confirm the reliability and validity of these methods.

Proton migration in hydrocarbons induced by slow highly charged ion impact

Different from most of the previous studies using light or photons, we use highly charged ions as projectiles to activate proton migration in the smallest saturated and unsaturated hydrocarbon molecules, i.e., CH₄ and C₂H₂. The H₃ ⁺ formation channel (H₃ ⁺ + CH⁺) and isomerization channel (C⁺ + CH₂ ⁺), serving as indicators of proton migration, are observed in the fragmentation of CH₄ and C₂H₂ dications. Corresponding kinematical information, i.e., kinetic energy release, is for the first time obtained in the collisions with highly charged ions. In particular, for the C⁺ + CH₂ ⁺ channel, a new pathway is identified, which is tentatively attributed to the isomerization on high-lying states of acetylene dication. The kinetic energy release spectra for other two-body breakup channels are also determined and precursor dication states could thus be identified.

Morphological variations among output neurons of the olfactory bulb in the frog (Rana ridibunda)

Morphological properties of putative output cells have been studied in detail in the olfactory bulb of frogs (Rana ridibunda). Intracellular injection of Lucifer Yellow was used to reconstruct individual neurons. Ten different anatomical features related to cell shape and position were studied quantitatively. The results show that output cells, generally considered to be a homogeneous group in the olfactory bulb of amphibians, are, in fact, quite different in their morphology. Using multidimensional analysis to examine differences among the output neurons, we found that they might be divided into at least two groups. In one group, the cell somata were located near the glomerular layer and the dendrites lay at large angles with respect to each other. In the other group, the cell somata were farther from the glomerular layer and their dendrites lay at smaller angles. From their morphology, these two cell groups appear to be homologous, respectively, to the superficial/middle tufted cells and deep tufted/mitral cells of mammals.

Effect of hyperoxia on pulmonary SIgA and its components, IgA and SC

Purpose

Oxygen therapy (hyperoxia) is essential for the treatment of some neonatal critical care conditions. The lung is the primary target for the changes induced by hyperoxia. Secretory immunoglobulin A (SIgA), IgA and secretory component (SC) reflect the local immunity in the respiratory tract induced by hyperoxia.

Methods

The enzyme-linked immunosorbent assay, immunohistochemistry staining, Western blot and Real-time PCR were used to detect the levels of cytokines, IgA and SIgA in bronchoalveolar lavage as well as IgA and SC/pIgR in pulmonary tissue.

Results

The levels of IgA and SIgA in BAL fluid were gradually increased following neonatal rat development. Compared with air-inhaling group, in the hyperoxia group IgA, SIgA and other cytokines except IL-1 in BAL fluid were significantly elevated on the 3rd, 5th and 7th days, but on the 10th day TNF-α, SIgA and IgA rapidly decreased. In the hyperoxia group, both the protein expression of SC/pIgR and the mRNA expression of SC/pIgR were remarkably increased on the 3rd, 5th and 7th days, but were significantly decreased on the 10th day, respectively. Conclusion: The large amount of SIgA, IgA and SC in the early period of hyperoxia might protect the lungs of the neonatal rats against acute pulmonary injury, however, in the late period of hyperoxia, the abruptly drop of SIgA and its component might lead to pulmonary immunity abnormality. In hyperoxia, the increased expression of cytokines might contribute to the expression of IgA and SC.

Surveillance for polio eradication in the People's Republic of China

A case-based virus surveillance system for wild poliovirus in China was developed. By 1993, all 30 provincial immunization units and, by 1994, all 29 provincial laboratories were sending computerized data to the national level. In 1993, a county-level, computerized map was operationalized that permitted visual monitoring of the progress of the polio eradication program every month by county. In 1993, wild poliovirus type 1 was detected in 8 provinces. Wild poliovirus mainly caused clusters of polio cases identified by a surveillance system that detected primarily clinical polio in children <5 years old (1 stool sample was collected on approximately 50% of reported cases). By 1995, the surveillance system had reached certification-like levels (80% of acute flaccid paralysis [AFP] patients with 2 stool specimens and AFP case rate of 1/100,000 children <15 years old). No indigenous wild poliovirus was detected in 1995. This general case-based model can be applied to measles and other important diseases, and may then lead to a more rapid decrease in adverse health outcomes.

Correlations between molecular profile and tumor location in Chinese patients with oligodendroglial tumors

OBJECTIVE

To investigate possible correlations between molecular alterations and tumor location in Chinese patients with oligodendroglial tumors.

METHODS

A series of 105 gliomas, including 42 oligoastrocytomas, and two control groups of 28 oligodendrogliomas and 35 astrocytomas, were retrospectively reviewed. In each case, the radiologic picture and loss of heterozygosity (LOH) on chromosome 1p and 19q detected by denaturing high-performance liquid chromatography (DHPLC) were analyzed. Correlations between molecular profile and tumor location were made by chi-square and Fisher's exact tests.

RESULTS

Oligodendroglial tumors located in the nontemporal lobes were significantly more likely to have combination of LOH 1p and LOH 19q than tumors arising in the insula, temporal lobe, and temporal with another lobe (p=0.001). Subgroup analysis confirmed this finding in oligodendrogliomas (p=0.006), but the difference did not reach significance in the oligoastrocytoma group, although the trend was similar (p=0.067). In contrast to the oligodendroglial tumors, we detected no association between molecular alterations and location for diffuse astrocytomas.

CONCLUSION

We conclude that molecular subsets of oligodendroglial tumors may arise preferentially in certain lobes of the brain, with tumors having LOH 1p and LOH 19q occurring most frequently in the nontemporal lobes. These findings suggest that molecular subsets of oligodendroglial tumors may arise from site-specific precursor cells, which has provided some information for the current management of these neoplasms in China.

Distinguishing between cellular and vasogenic edema in head injured patients with focal lesions using magnetic resonance imaging

Having determined that edema and not vascular engorgement is the major factor leading to traumatic brain swelling, the objective of this study was to determine which type of edema, cellular or vasogenic, is responsible for increased tissue water in patients with focal lesions. Severely head injured patients (GCS 8 or less) were transported to imaging suites for measurement of brain water and apparent diffusion coefficient (ADC) using magnetic resonance technique. Cerebral blood flow by stable Xenon method was also measured in the regions of interest. Brain water was increased significantly in the hemisphere with lesion. The increase in water was associated with reduced ADC signifying a predominant cellular edema. The ADC in the contralateral hemisphere was near normal value. Cerebral blood flow values in the regions of interest were above ischemic levels suggesting that factors other than ischemia are responsible for the cytotoxic swelling in patients with focal injury.

Association of prenatal renal ultrasound abnormalities with pathogenic copy number variants in a large Chinese cohort

OBJECTIVES

To assess the clinical utility of prenatal chromosomal microarray analysis (CMA) in fetuses with abnormal renal sonographic findings, and to evaluate the association of pathogenic or likely pathogenic copy number variants (P/LP CNVs) with different types of renal abnormality.

METHODS

This was a retrospective study of fetuses at 14-36 weeks screened routinely for renal and other structural abnormalities at the Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region. We retrieved and analyzed data from fetuses with abnormal renal sonographic findings, examined between January 2013 and November 2019, which underwent CMA analysis using tissue obtained from chorionic villus sampling (CVS), amniocentesis or cordocentesis. We evaluated the CMA findings according to type of renal ultrasound anomaly and according to whether renal anomalies were isolated or non-isolated.

RESULTS

Ten types of renal anomaly were reported on prenatal ultrasound screening, at a mean ± SD gestational age of 24.9 ± 4.8 weeks. The anomalies were diagnosed relatively late in this series, as 64% of cases with an isolated renal anomaly underwent cordocentesis rather than CVS. Fetal pyelectasis was the most common renal ultrasound finding, affecting around one-third (34.32%, 301/877) of fetuses with a renal anomaly, but only 3.65% (n = 11) of these harbored a P/LP CNV (comprising: isolated cases, 2.37% (4/169); non-isolated cases, 5.30% (7/132)). Hyperechogenic kidney was found in 5.47% (n = 48) of fetuses with a renal anomaly, of which 39.58% (n = 19) had a P/LP CNV finding (comprising: isolated cases, 44.44% (16/36); non-isolated cases, 25.00% (3/12)), the highest diagnostic yield among the different types of renal anomaly. Renal agenesis, which accounted for 9.92% (n = 87) of all abnormal renal cases, had a CMA diagnostic yield of 12.64% (n = 11) (comprising: isolated cases, 11.54% (9/78); non-isolated cases, 22.22% (2/9); unilateral cases, 11.39% (9/79); bilateral cases, 25.00% (2/8)), while multicystic dysplastic kidney (n = 110), renal cyst (n = 34), renal dysplasia (n = 27), crossed fused renal ectopia (n = 31), hydronephrosis (n = 98), renal duplication (n = 42) and ectopic kidney (n = 99) had overall diagnostic rates of 11.82%, 11.76%, 7.41%, 6.45%, 6.12%, 4.76% and 3.03%, respectively. Compared with the combined group of CMA-negative fetuses with any other type of renal anomaly, the rate of infant being alive and well at birth was significantly higher in CMA-negative fetuses with isolated fetal pyelectasis or ectopic kidney, whereas the rate was significantly lower in fetuses with isolated renal agenesis, multicystic dysplastic kidney or severe hydronephrosis. The most common pathogenic CNV was 17q12 deletion, which accounted for 30.14% (22/73) of all positive CMA findings, with a rate of 2.51% (22/877) among fetuses with an abnormal renal finding. Fetuses with 17q12 deletion exhibited a wide range of renal phenotypes. Other P/LP CNVs in the recurrent region that were associated with prenatal renal ultrasound abnormalities included 22q11.2, Xp21.1, Xp22.3, 2q13, 16p11.2 and 1q21, which, collectively, accounted for 2.17% (19/877) of the fetuses with prenatal renal anomalies.

CONCLUSIONS

In this retrospective review of CMA findings in a large cohort of fetuses with different types of renal ultrasound abnormality, the P/LP CNV detection rate varied significantly (3.03-39.58%) among the different types of kidney anomaly. Our data may help in the decision regarding whether to perform prenatal genetic testing in fetuses with renal ultrasound findings. Specifically, prenatal CMA testing should be performed in cases of hyperechogenic kidney, regardless of whether or not the anomaly is isolated, while it should be performed postnatally rather than prenatally in cases of fetal pyelectasis. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Analysis of differentially co-expressed genes based on microarray data of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer related death worldwide. Although great progress in diagnosis and management of HCC have been made, the exact molecular mechanisms remain poorly understood. The study aims to identify potential biomarkers for HCC progression, mainly at transcription level. In this study, chip data GSE 29721 was utilized, which contains 10 HCC samples and 10 normal adjacent tissue samples. Differentially expressed genes (DEGs) between two sample types were selected by t-test method. Following, the differentially co-expressed genes (DCGs) and differentially co-expressed Links (DCLs) were identified by DCGL package in R with the threshold of q < 0.25. Afterwards, pathway enrichment analysis of the DCGs was carried out by DAVID. Then, DCLs were mapped to TRANSFAC database to reveal associations between relevant transcriptional factors (TFs) and their target genes. Quantitative real-time RT-PCR was performed for TFs or genes of interest. As a result, a total of 388 DCGs and 35,771 DCLs were obtained. The predominant pathways enriched by these genes were Cytokine-cytokine receptor interaction, ECM-receptor interaction and TGF-β signaling pathway. Three TF-target interactions, LEF1-NCAM1, EGR1-FN1 and FOS-MT2A were predicted. Compared with control, expressions of the TF genes EGR1, FOS and ETS2 were all up-regulated in the HCC cell line, HepG2; while LEF1 was down-regulated. Except NCAM1, all the target genes were up-regulated in HepG2. Our findings suggest these TFs and genes might play important roles in the pathogenesis of HCC and may be used as therapeutic targets for HCC management.

Adsorption of Pb and Zn from binary metal solutions and in the presence of dissolved organic carbon by DTPA-functionalised, silica-coated magnetic nanoparticles

The ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated magnetic nanoparticles to adsorb Pb and Zn from single and bi-metallic metal solutions and from solutions containing dissolved organic carbon was assessed. In all experiments 10 mL solutions containing 10 mg of nanoparticles were used. For single metal solutions (10 mg L^-1 Pb or Zn) at pH 2 to 8, extraction efficiencies were typically >70%. In bi-metallic experiments, examining the effect of a background of either Zn or Pb (0.025 mmol L^-1) on the adsorption of variable concentrations (0-0.045 mmol L^-1) of the other metal (Pb or Zn, respectively) adsorption was well modelled by linear isotherms (R² > 0.60; p ≤ 0.001) and Pb was preferentially adsorbed relative to Zn. In dissolved organic carbon experiments, the presence of fulvic acid (0, 2.1 and 21 mg DOC L^-1) reduced Pb and Zn adsorption from 0.01, 0.1 and 1.0 mmol L^-1 solutions. However, even at 21 mg DOC L^-1 fulvic acid, extraction efficiencies from 0.01 to 0.1 mmol L^-1 solutions remained >80% (Pb) and >50% (Zn). Decreases in extraction efficiency were significant between initial metal concentrations of 0.1 and 1.0 mmol L^-1 indicating that at metal loadings between c. 100 mg kg^-1 and 300 mg kg^-1 occupancy of adsorption sites began to limit further adsorption. The nanoparticles have the potential to perform effectively as metal adsorbents in systems containing more than one metal and dissolved organic carbon at a range of pH values.

Insertion and deletion mutations in the repA4 region of the IncFII plasmid NR1 cause unstable inheritance

Mutants of IncFII plasmid NR1 that have transposons inserted in the repA4 open reading frame (ORF) are not inherited stably. The repA4 ORF is located immediately downstream from the replication origin (ori). The repA4 coding region contains inverted-repeat sequences that are homologous to the terC inverted repeats located in the replication terminus of the Escherichia coli chromosome. The site of initiation of leading-strand synthesis for replication of NR1 is also located in repA4 near its 3' end. Transposon insertions between ori and the right-hand terC repeat resulted in plasmid instability, whereas transposon insertions farther downstream did not. Derivatives that contained a 35-bp frameshift insertion in the repA4 ORF were all stable, even when the frameshift was located very near the 5' end of the coding region. This finding indicates that repA4 does not specify a protein product that is essential for plasmid stability. Examination of mutants having a nest of deletions with endpoints in or near repA4 indicated that the 3' end of the repA4 coding region and the site of leading-strand initiation could be deleted without appreciable effect on plasmid stability. Deletion of the pemI and pemK genes, located farther downstream from repA4 and reported to affect plasmid stability, also had no detectable effect. In contrast, mutants from which the right-hand terC repeat, or both right- and left-hand repeats, had been deleted were unstable. None of the insertion or deletion mutations in or near repA4 affected plasmid copy number. Alteration of the terC repeats by site-directed mutagenesis had little effect on plasmid stability. Plasmid stability was not affected by a fus mutation known to inactivate the termination function. Therefore, it appears that the overall integrity of the repA4 region is more important for stable maintenance of plasmid NR1 than are any of the individual known features found in this region.

Therapeutic effects of dengue 2 virus capsid protein and staphylococcal nuclease fusion protein on dengue-infected cell cultures

Dengue infection poses a serious public health problem in most tropical and subtropical areas. No effective antiviral drugs or vaccines are currently available against dengue infection. To explore the feasibility of using capsid-targeted viral inactivation (CTVI) as an antiviral strategy against dengue infection, we constructed a plasmid expressing a fusion protein consisting of staphylococcal nuclease (SN) fused to dengue 2 virus capsid protein (D2C), and investigated its effects on the production of infectious virions when introduced into BHK cells infected with dengue virus. The results indicated that D2C-SN can be expressed and tolerated in this mammalian cell culture. The enzymatically active SN moiety was incorporated into nascent virions during the process of viral assembly. By comparing the effects of incorporated SN and SN*, an enzymatically inactive missense mutant form of wild-type SN, on the infectivity of progeny virions, we clearly demonstrated that nucleolytic activity was the major antiviral mechanism. Expression of D2C-SN fusion protein as a therapeutic agent resulted in a reduction in infectious titers of 12- to 60-fold. Therefore, dengue virus may be particularly vulnerable to a CTVI therapeutic approach.

Genome-wide compound heterozygosity analysis highlighted 4 novel susceptibility loci for congenital heart disease in Chinese population

Genome-wide association studies (GWASs) have achieved great success in deciphering the genetic cause of congenital heart disease (CHD). However, the heritability of CHD remains to be clarified, and numerous genetic factors responsible for occurrence of CHD are yet unclear. In this study, we performed a genome-wide search for relaxed forms of compound heterozygosity (CH) in association with CHD using our existing GWAS data including 2265 individuals (957 CHD cases and 1308 controls). CollapsABEL was used to iteratively test the association between the CH genotype and the CHD phenotype in a sliding window manner. We highlighted 17 genetic loci showing suggestive CH-like associations with CHD (P < 5 × 10^-8 ), among which 4 genetic loci had expression quantitative trait loci (eQTL) effects in blood (P_eQTL  < 0.01). After conditional association analysis, each loci had only 1 independently effective signal reaching the significance threshold (rs2071477/rs3129299 at 6p21.32, P = 2.47 × 10^-10 ; rs10773097/rs2880921 at 12q24.31, P = 3.30 × 10^-8 ; rs73032040/rs7259476 at 19q13.11, P = 1.14 × 10^-8 ; rs10416386/rs4239517 at 19q13.31, P = 1.15 × 10^-9 ), together explained 7.83% of the CHD variance. Among these 4 associated loci, outstanding candidates for CHD-associated genes included UBC, CFM2, ZNF302, LYPD3 and CADM4. Although replication studies with larger sample size are warranted, the first CH GWAS of CHD may extend our current knowledge of the genetic contributions to CHD in the Han Chinese population.

Biotype status and distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) in Shandong province of China based on mitochondrial DNA markers

Bemisia tabaci has caused significant crop losses in China during the last decade. Recent research has shown that two potentially invasive variants, biotypes B and Q, have been found in several regions of China. Our objective was to determine the biotype status and the distribution of B. tabaci in Shandong province, an important agricultural region of China. Based on mitochondrial DNA markers, both biotypes B and Q were detected, with B being the predominant biotype. The results indicate that the more recently introduced biotype Q has not only been located in China but also has established and spread in some regions.