海洋微生物抗菌脂肽及新生物农药研发

近年来,微生物脂肽作为生物农药的研究与应用,在国内外得到了广泛重视,成为今后生物农药发展的一个重要方向。从不同生境分离获得多批海洋微生物,通过筛选抗植物病原真菌活性强的菌株,发酵、分离、纯化及鉴定其代谢产物,从3种芽胞杆菌中发现了6个新的抗菌脂肽,属于iturins和fengycin类化合物。芽胞杆菌的芽胞及脂肽可研发防治植物真菌病害新生物农药。     

高等动物细胞核膜和核纤层结构、功能及动态变化调控机制

细胞核是真核细胞中最大的细胞器．高等动物细胞核主要由双层核膜、核孔复合体、核纤层、染色质和核仁等组成．在细胞有丝分裂期,细胞核呈现去装配和再装配等动态变化．在细胞分裂间期,核膜、核孔复合体和核纤层构成细胞核的外周结构,为遗传物质在染色质和核仁中的代谢提供了一个相对稳定的环境,同时调控细胞核内外的物质转运,在细胞增殖、分化、个体发育和细胞衰老等许多方面发挥着重要作用．本文主要对高等动物细胞核膜和核纤层结构、功能及动态变化调控机制等方面的研究进展进行简要综述．     

Newly discovered insect RNA viruses in China

Insects are a group of arthropods and the largest group of animals on Earth,with over one million species described to date.Like other life forms,insects suffer from viruses that cause disease and death.Viruses that are pathogenic to beneficial insects cause dramatic economic losses on agriculture.In contrast,viruses that are pathogenic to insect pests can be exploited as attractive biological control agents.All of these factors have led to an explosion in the amount of research into insect viruses in recent years,generating impressive quantities of information on the molecular and cellular biology of these viruses.Due to the wide variety of insect viruses,a better understanding of these viruses will expand our overall knowledge of their virology.Here,we review studies of several newly discovered RNA insect viruses in China.     

Reducing AsA Leads to Leaf Lesion and Defence Response in Knock-Down of the AsA Biosynthetic Enzyme GDP-D-Mannose Pyrophosphorylase Gene in Tomato Plant

As a vital antioxidant, L-ascorbic acid (AsA) affects diverse biological processes in higher plants. Lack of AsA in cell impairs plant development. In the present study, we manipulated a gene of GDP-mannose pyrophosphorylase which catalyzes the conversion of D-mannose-1-P to GDP-D-mannose in AsA biosynthetic pathway and found out the phenotype alteration of tomato. In the tomato genome, there are four members of GMP gene family and they constitutively expressed in various tissues in distinct expression patterns. As expected, over-expression of SlGMP3 increased total AsA contents and enhanced the tolerance to oxidative stress in tomato. On the contrary, knock-down of SlGMP3 significantly decreased AsA contents below the threshold level and altered the phenotype of tomato plants with lesions and further senescence. Further analysis indicated the causes for this symptom could result from failing to instantly deplete the reactive oxygen species (ROS) as decline of free radical scavenging activity. More ROS accumulated in the leaves and then triggered expressions of defence-related genes and mimic symptom occurred on the leaves similar to hypersensitive responses against pathogens. Consequently, the photosynthesis of leaves was dramatically fallen. These results suggested the vital roles of AsA as an antioxidant in leaf function and defence response of tomato.     

Cancer Incidence and Mortality in Patients with Type 2 Diabetes Treated with Human Insulin: A Cohort Study in Shanghai

Aim

The aim was to investigate the association between human insulin and cancer incidence and mortality in Chinese patients with type 2 diabetes.

Methods

We recruited 8,774 insulin-naïve diabetes patients from the Shanghai Diabetes Registry (SDR). The follow-up rate was 85.4%. All subjects were divided into the insulin use cohort (n = 3,639) and the non-insulin use cohort (n = 5,135). The primary outcome was the first diagnosis of any cancer. The secondary outcome was all-cause mortality. Cox proportional hazards model was used to estimate the relative risk (RR) of cancer and mortality.

Results

We observed 98 cancer events in the insulin use cohort and 170 in the non-insulin use cohort. Cancer incidence rates were 78.6 and 74.3 per 10,000 patients per year in the insulin users and the non-insulin users, respectively. No significant difference in cancer risk was observed between the two cohorts (adjusted RR = 1.20, 95% CI 0.89–1.62, P = 0.228). Regarding site-specific cancers, only the risk of liver cancer was significantly higher in the insulin users compared to that in the non-insulin users (adjusted RR = 2.84, 95% CI 1.12–7.17, P = 0.028). The risks of overall mortality (adjusted RR = 1.89, 95% CI 1.47–2.43, P<0.0001) and death from cancer (adjusted RR = 2.16, 95% CI 1.39–3.35, P = 0.001) were all significantly higher in the insulin users than in the non-insulin users.

Conclusion

There was no excess risk of overall cancer in patients with type 2 diabetes who were treated with human insulin. However, a significantly higher risk of liver cancer was found in these patients. Moreover, insulin users showed higher risks of overall and cancer mortality. Considering that individuals treated with insulin were more likely to be advanced diabetic patients, caution should be used in interpreting these results.     

The Significance of Notch1 Compared with Notch3 in High Metastasis and Poor Overall Survival in Hepatocellular Carcinoma

Background

The prognosis for patients with hepatocellular carcinoma (HCC) is poor, and the mechanisms underlying the development of HCC remain unclear. Notch1 and Notch3 may be involved in malignant transformation, although their roles remain unknown.

Materials and Methods

HCC tissues were stained with anti-Notch1 or -Notch3 antibody. The migration and invasion capacities of the cells were measured with transwell cell culture chambers. RT-PCR was used to measure the expression of Notch1 and Notch3 mRNA. Additionally, western blot analysis was used to assess the protein expression of Notch1, Notch3, CD44v6, E-cadherin, matrix metalloproteinase-2 (MMP-2), MMP-9, and urokinase-type plasminogen activator (uPA). RNA interference was used to down-regulate the expression of Notch1 and Notch3. Cell viability was assessed using MTT.

Results

Based on immunohistochemistry, high Notch1 expression was correlated with tumor size, tumor grade, metastasis, venous invasion and AJCC TNM stage. High Notch3 expression was only strongly correlated with metastasis, venous invasion and satellite lesions. Kaplan-Meier curves demonstrated that patients with high Notch1 or Notch3 expression were at a significantly increased risk for shortened survival time. In vitro, the down-regulation of Notch1 decreased the migration and invasion capacities of HCC cells by regulating CD44v6, E-cadherin, MMP-2, MMP-9, and uPA via the COX-2 and ERK1/2 pathways. Down-regulation of Notch3 only decreased the invasion capacity of HCC cells by regulating MMP-2 and MMP-9 via the ERK1/2 pathway.

Conclusions

Based on the migration and invasion of HCC, we hypothesize that targeting Notch1 may be more useful than Notch3 for designing novel preventive and therapeutic strategies for HCC in the near future.     

A retrospective analysis of 140 patients with giant cell tumor in the extremity: A multicenter study based on four hospitals in South China

Background: Update reports are rarely available regarding the bone giant cell tumors (GCTs) in the extremity in Chinese people. The aim of this study was to review the epidemiological characteristics of bone GCT in the extremity based on the clinical data from four hospitals in South China. Methods: We searched medical electronic records from January 2001 to December 2011 in four hospitals in South China to identify patients with definite diagnosis of extremity GCT. Epidemiological data including gender, tumor site, age at the time of first diagnosis, local recurrence and pulmonary metastasis were collected and analyzed statistically. Differences between-genders were particularly analyzed regarding first diagnosis age, tumor site, local recurrence and pulmonary metastasis. T-test and Chi-square test were used for continuous and dichotomous variables, respectively. Results: A total of 140 GCT patients (87 males and 53 females) were identified. The gender ratio was 1.64 for a male predominance. GCTs were mostly located around the knee (67 cases). 92 patients were in their 20s to 40s upon first diagnosis. The average age at the time of first diagnosis for all was 30.49 years, 30.76 years for males and 30.06 years for females (P = 0.757). GCT recurred locally in 50 patients (26 males and 24 females) with no gender difference (P = 0.065). The average interval from first surgery to local recurrence was 21.42 months. Pulmonary metastasis was found in 11 patients (8 males and 3 females) also with no gender difference (P = 0.667). The average interval from first diagnosis to metastasis was 36.45 months. Conclusions: Extremity GCT may have a male predominance in Chinese population and mostly occur at 20–40 years of age and around the knee. Follow-ups for GCT patients should be carried on for at least 3 years after primary surgery according to the average intervals for possible local recurrence and pulmonary metastasis.     

Synergistic Effects of GhSOD1 and GhCAT1 Overexpression in Cotton Chloroplasts on Enhancing Tolerance to Methyl Viologen and Salt Stresses

In plants, CuZn superoxide dismutase (CuZnSOD, EC l.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), and catalase (CAT, EC l.11.1.6) are important scavengers of reactive oxygen species (ROS) to protect the cell from damage. In the present study, we isolated three homologous genes (GhSOD1, GhAPX1, and GhCAT1) from Gossypium hirsutum. Overexpressing cassettes containing chimeric GhSOD1, GhAPX1, or GhCAT1 were introduced into cotton plants by Agrobacterium transformation, and overexpressed products of these genes were transported into the chloroplasts by transit peptide, as expected. The five types of transgenic cotton plants that overexpressed GhSOD1, GhAPX1, GhCAT1, GhSOD1 and GhAPX1 stack (SAT), and GhSOD1 and GhCAT1 stack (SCT) were developed. Analyses in the greenhouse showed that the transgenic plants had higher tolerance to methyl viologen (MV) and salinity than WT plants. Interestingly, SCT plants suffered no damage under stress conditions. Based on analyses of enzyme activities, electrolyte leakage, chlorophyll content, photochemical yield (Fv/Fm), and biomass accumulation under stresses, the SCT plants that simultaneously overexpressed GhSOD1 and GhCAT1 appeared to benefit from synergistic effects of two genes and exhibited the highest tolerance to MV and salt stress among the transgenic lines, while the SAT plants simultaneously overexpressing GhSOD1 and GhAPX1 did not. In addition, transgenic plants overexpressing antioxidant enzymes in their chloroplasts had higher tolerance to salt stress than those expressing the genes in their cytoplasms, although overall enzyme activities were almost the same. Therefore, the synergistic effects of GhSOD1 and GhCAT1 in chloroplasts provide a new strategy for enhancing stress tolerance to avoid yield loss.