Gut bacterium promotes host fitness in special ecological niche by affecting sugar metabolism in Drosophila suzukii.

As an important fruit pest of global significance, Drosophila suzukii occupies a special ecological niche, with the characteristics of high sugar and low protein contents. This niche differs from those occupied by other fruit-damaging Drosophila species. Gut bacteria substantially impact the physiology and ecology of insects. However, the contribution of gut microbes to the fitness of D. suzukii in their special ecological niche remains unclear. In this study, the effect of Klebsiella oxytoca on the development of D. suzukii was examined at physiological and molecular levels. The results showed that, after the removal of gut microbiota, the survival rate and longevity of axenic D. suzukii decreased significantly. Reintroduction of K. oxytoca to the midgut of D. suzukii advanced the development level of D. suzukii. The differentially expressed genes and metabolites between axenic and K. oxytoca-reintroduced D. suzukii were enriched in the pathways of carbohydrate metabolism. This advancement was achieved through an increased glycolysis rate and the regulation of the transcript level of key genes in the glycolysis/gluconeogenesis pathway. Klebsiella oxytoca is likely to play an important role in increasing host fitness in their high-sugar ecological niche by stimulating the glycolysis/gluconeogenesis pathway. As a protein source, bacteria can also provide direct nutrition for D. suzukii, which depends on the quantity or biomass of K. oxytoca. This result may provide a new target for controlling D. suzukii by inhibiting sugar metabolism through eliminating the effect of K. oxytoca and thus disrupting the balance of gut microbial communities.

Oviposition Suitability of Drosophila Suzukii (Diptera: Drosophilidae) for Nectarine Varieties and Its Correlation with the Physiological Indexes.

The nectarine is an important fruit, which is attacked by Drosophila suzukii in Europe and the United States but there are no reports of it attacking nectarines in China. Here, we determined the oviposition preference of D. suzukii six on intact and sliced nectarine varieties in China and how physical and physiological indexes of the fruit correlate with these preferences. D. suzukii were allowed to oviposit on two early-, two middle- and two late-maturing varieties of nectarine-Shuguang and Chunguang, Fengguang and Zhong you 4, Zhong you 7 and Zhong you 8, respectively and the number of larvae also followed the order. The firmness, soluble solids content and the nutritional components of the amino acid, protein, soluble sugar and pectin contents of each variety were measured. D. suzukii preferred the early Shuguang variety, followed by the early Chunguang variety and then the middle Zhong you 4 and Fengguang varieties. Taken together, results show that D. suzukii shows preferences for earlier rather than later varieties of nectarines in China and that these preferences are related to the fruit's physical and physiological traits. Results suggest that mixed cultivation of early-, middle- and late-maturing nectarine varieties should be avoided in order to prevent fly dispersal and infestation by D. suzukii.

In vitro arsenic trioxide induces apoptosis in T cells of asthmatic patients by a Bcl-2 related mechanism.

This study examined the effects of arsenic trioxide on apoptosis and interleukin-4 release in T cells of asthmatic patients in vitro and investigated the role of Bcl-2 in the active mechanism. T cells were isolated from asthmatic patients (n = 21) and healthy controls (n = 20), and then treated with arsenic trioxide and dexamethasone. Cell apoptosis was measured using fluorescence microscopy, flow cytometry and a cytochrome c ELISA kit. Interleukin-4 levels in the serum and in supernatants from T cells were quantified by ELISA. Flow cytometric analysis and immunofluorescence studies were performed to determine Bcl-2 expression. T cells of the asthmatic patients (i. e. without treatment) exhibited decelerated spontaneous apoptosis after 24 h incubation in vitro when compared to T cells of the healthy controls. With dexamethasone treatment, an increase in apoptosis of T cells was not significantly different between both groups, irrespective of the method used. Arsenic trioxide treatment, however, significantly increased the apoptosis of T cells of the asthmatic group and showed a slight effect on the control group. In asthmatic patients, elevated levels of interleukin-4 and up-regulated Bcl-2 expression were detected. Moreover, in vitro, T cells of asthmatic patients spontaneously released more interleukin-4 and exhibited more Bcl-2 expression than T cells from the control group. Arsenic trioxide treatment significantly decreased interleukin-4 release and down-regulated Bcl-2 expression in asthmatic patients, while it only slightly affected healthy controls. Dexamethasone treatment decreased interleukin-4 release in both groups examined. It did not significantly influence Bcl-2 expression. These results suggest that arsenic trioxide induces T cell apoptosis and decreases interleukin-4 release in T cells of asthmatic patients in vitro and that down-regulation of Bcl-2 expression may be an important mechanism.

[Clinical observation of teacher tablets in treatment of pharyngitis].

OBJECTIVE: To evaluate the efficacy of teacher tablets in the treatment of pharyngitis. METHOD: One hundred and thirty six patients with acute pharyngitis or chronic pharyngitis in attack were randamly divided into two groups: treated group (n=68), the patients were given teacher tablets for 7 days, control group (n=68), the patients were given Qinlian capsule for 7 days. Before and after the experimental medicine-taking test, general condition, clinical symptoms and features of examinations on laryngo-pharynx, throat swab bacterial culture were measured. RESULT: After 7 day medicine-taking experiment, teacher tablets can improve clinical symptoms (at an efficacy rate of more than 60%) and features (at an efficacy rate of more than 80%) of laryngopharynx, in treated group, the inhibition ratios of alpha streptococcus, neisseria and staphylococcus aureus are more than 50%. There are no significant difference between treated group and control groups in those detected index. CONCLUSION: Teacher tablets is effective for pharyagitis.

[Effects of arsenic trioxide on apoptosis of peripheral T-lymphocytes from asthmatic patients and normal subjects in vitro].

OBJECTIVE: To study the effects of arsenic trioxide on apoptosis of peripheral T-lymphocytes from asthmatic patients and normal subjects in vitro. METHODS: The T-lymphocytes were isolated from the blood of 21 asthmatic patients and 20 healthy controls and treated with arsenic trioxide and dexamethasone. Cell apoptosis was observed by fluorescence microscope and measured with flow cytometry and Cytochrome C ELISA kit. RESULTS: The T-lymphocytes from the asthmatic patients, when compared to those from of the healthy control, exhibited decelerated spontaneous apoptosis after a 24-hour incubation in vitro. Dexamethasone treatment significantly increased the percentage of apoptotic T-lymphocytes from both asthmatic patients and normal subjects in comparable magnitude. Arsenic trioxide treatment, in contrast, significantly increased the percentage of apoptotic T-lymphocytes from asthmatic patients, but slightly affected the cells from the control group. CONCLUSIONS: Spontaneous apoptosis of T-lymphocytes can be decelerated in asthmatic patients, whose T-lymphocytes are more sensitive to arsenic trioxide-induced apoptosis than those of normal subjects, but the T-lymphocytes from normal subjects and asthmatic patients are equally sensitive to dexamethasone.