Pseudomonas mosselii: a potential alternative for managing pyrethroid-resistant Aedes aegypti.

BACKGROUND: Aedes aegypti is a widespread mosquito in tropical and subtropical regions that causes significant mortality and morbidity in humans by transmitting diseases, such as dengue fever and Zika virus disease. Synthetic insecticides, such as pyrethroids, have been used to control Ae. aegypti, but these insecticides can also affect nontarget organisms and contaminate soil and water. This study aimed to investigate the mosquitocidal activity of Pseudomonas mosselii isolated from pond sludge against larvae of Ae. aegypti. RESULTS: Based on the initial results, similar time-course profiles were obtained for the mosquitocidal activity of the bacterial culture and its supernatant, and the pellet resuspended in Luria-Bertani (LB) medium also showed delayed toxicity. These results imply that the toxic component can be released into the medium from live bacteria. Further research indicated that the toxic component appeared in the supernatant approximately 4 h after a 3-mL stock was cultured in 200 mL of LB medium. The stabilities of the P. mosselii culture and supernatant stored at different temperatures were also evaluated, and the best culture stability was obtained at 28 °C and supernatant stability at 4 °C. The bacterial culture and supernatant were toxic to larvae and pupae of not only susceptible Ae. aegypti but also pyrethroid-resistant strains. CONCLUSION: This study highlights the value of the mosquitocidal activity of P. mosselii, which has potential as an alternative insecticide to control pyrethroid-resistant Ae. aegypti in the field. © 2024 Society of Chemical Industry.

Quantification of Salivary Arecoline, Arecaidine and N-Methylnipecotic Acid Levels in Volunteers by Liquid Chromatography-Tandem Mass Spectrometry.

Relatively little is known about the metabolism of areca nut in human saliva. We here describe the simultaneous quantification of areca nut metabolites: arecoline, arecaidine and N-methylnipecotic acid in saliva samples after chewing one 5 g areca nut by using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Time courses of salivary areca nut metabolites in five adult male areca nut chewer volunteers were investigated. The limits of quantification were all 1.25 ng/mL for arecoline, arecaidine and N-methylnipecotic acid. Intra- and interday imprecisions were <4.2 and 13.6%, respectively. The within-day accuracy ranged from 82.2 to 116.7%, and the between-day accuracy ranged from 78.3 to 115.6%. Through areca nut chewing time course study, we found that salivary arecoline, arecaidine and N-methylnipecotic acid concentrations varied greatly over time between experiment individuals. Our findings suggest that arecoline might be metabolized slightly to arecaidine at 30 min after areca nut chewing and arecoline might be metabolized slightly to N-methylnipecotic acid at 25 min after areca nut chewing in the mouth. We first provide simultaneous quantification of human salivary arecoline, arecaidine and N-methylnipecotic acid levels using LC-MS-MS. This method may facilitate future research design in the pathogenic effects of areca nut exposure.

Enhanced expression of plasminogen activator inhibitor may prevent cardiac rupture in female and castrated mice after myocardial infarction.

OBJECTIVE: The objective of this study was to test the hypothesis that gender has a significant impact on cardiac inflammation, fibrosis, and survival after myocardial infarction (MI) in a murine model of left coronary artery ligation (CAL) by investigating the underlying cellular-molecular mechanisms. METHODS: Age-matched male and female mice were randomly assigned into 6 groups: sham-operated males, sham-operated females, intact males with CAL, intact females with CAL, castrated males with CAL, and oophorectomized females with CAL. The animals were sacrificed 14 days postoperatively. The hearts from each group were harvested for morphologic studies (n = 6) (infarct and fibrotic area, inflammatory cell markers CD40 and CD68) and mRNA expression analyses (n = 6) of pro- and antiinflammatory molecules, including matrix metalloproteinase (MMP)-9, plasminogen activator inhibitor (PAI)-1, interleukin (IL)-10, transforming growth factor (TGF)-ß, and endothelial nitric oxide synthase (eNOS). RESULTS: Intact males with CAL had significantly lower 14-day survival compared with intact females with CAL. Similarly, the infarct areas in intact males with CAL were largest compared with other CAL animals. The fibrotic area was also larger in intact males with CAL than in intact females with CAL. Numbers of CD40(+)/CD68(+) cells and MMP-9 expression were higher in intact males with CAL than in intact females with CAL and castrated males with CAL. IL-10, eNOS, and TGF-ß were significantly suppressed in oophorectomized females with CAL compared with intact females with CAL. Intact females with CAL and castrated males with CAL exhibited notably enhanced post-MI PAI-1 expression. CONCLUSIONS: Male gender (compared with female) may be an unfavorable prognostic factor after MI in terms of enhanced inflammation and fibrosis in a murine model. Although castration seemed to be significantly antiinflammatory and antifibrotic after MI, oophorectomy had no significant impact on survival, suggesting that factors other than estrogen may account for favorable outcome after MI in the female gender. Furthermore, enhanced postinfarct PAI-1 expression in castrated and female mice may contribute to suppressed MMP-9 expression and survival advantage.

[Diagnosis and surgical treatment of carcinoid tumors of the appendix in 64 patients].

OBJECTIVE: To summarize the experience in the diagnosis and surgical treatment of carcinoid tumors of the appendix. METHODS: From 1972 to 2006, 64 patients with carcinoid tumors of the appendix received surgical treatment in our hospitals. The clinical data of those patients were retrospectively analyzed. RESULTS: Of the 64 cases, only 6 cases (9.4%) were correctly diagnosed preoperatively, while 58 (90.6%) not confirmed, with a misdiagnosis rate of 90.6%. All patients underwent surgical treatment, including appendectomy in 54, ileocecectomy in 4, right hemicolectomy in 2 and right hemicolectomy with regional lymph node dissection in 4 cases. The operation modes were determined according to the doctor's judgments based on the age of the patients, the nature, size, location, infiltration depth and lymph node metastasis of the tumors. Of the 64 patients, 58 were followed up with a longest follow-up period of 13 years, while 6 lost follow-up. Fifty-seven of those were still surviving, only one died of liver metastasis at 13 years after operation. CONCLUSION: Carcinoid tumor of the appendix is rare with a high rate of misdiagnosis before operation. Surgical resection is the only effective treatment for this disease and proper operation mode is the key to achieve good survival.

[Effects of different calcium salts on freezing resistance of satsuma mandarin].

The study on the effects of foliar spraying 20 mmol x L(-1) of CaCl2, Ca (NO3)2 and CaAc2 on the freezing resistance of satsuma mandarin (Citrus unshiu Marc. cv. Guoqing No. 1) showed that after treated with these Ca salts, the leaves of test plant had a lower half lethal temperature (LT50) than the control (sprayed with distilled water). The LT50 after treated with CaCl2 was 0.54 degrees C lower, whereas that after treated with CaAc2 and Ca (NO3)2 was 1.34 degrees C and 1.35 degrees C lower, respectively, implying that the latter two Ca salts were more effective in enhancing the freezing resistance of satsuma mandarin. Moreover, foliar spraying Ca salts increased the superoxidase (SOD) and peroxidase (POD) activities and the contents of soluble proteins, soluble sugars and praline in leaves, and decreased the leaf MDA content.

Characterization of an LQT5-related mutation in KCNE1, Y81C: implications for a role of KCNE1 cytoplasmic domain in IKs channel function.

BACKGROUND: Y81C is a new long QT-5 (LQT5)-related KCNE1 mutation, which is located in the post-transmembrane domain (post-TMD) region in close proximity to three other LQT5 mutations (S74L, D76N, and W87R). OBJECTIVE: We examine the effects of Y81C on the function and drug sensitivity of the slow delayed rectifier channel (I(Ks)) formed by KCNE1 with pore-forming KCNQ1 subunits. We also infer a structural basis for the detrimental effects of Y81C on I(Ks) function. METHODS: Wild-type (WT) and mutant (harboring Y81C) I(Ks) channels are expressed in oocytes or COS-7 cells. Channel function and KCNQ1 protein expression/subcellular distribution are studied by techniques of electrophysiology, biochemistry, and immunocytochemistry. Ab initio structure predictions of KCNE1 cytoplasmic domain are performed by the Robetta server. RESULTS: Relative to WT KCNE1, Y81C reduces I(Ks) current amplitude and shifts the voltage range of activation to a more positive range. Y81C does not reduce whole-cell KCNQ1 protein level or interfere with KCNQ1 trafficking to cell surface. Thus, its effects are mediated by altered KCNQ1/KCNE1 interactions in cell surface channels. Importantly, Y81C potentiates the effects of an I(Ks) activator. Preserving the aromatic or hydroxyl side chain at position 81 (Y81F or Y81T) does not prevent the detrimental effects of Y81C. Structure predictions suggest that the post-TMD region of KCNE1 may adopt a helical secondary structure. CONCLUSION: We propose that the post-TMD region of KCNE1 interacts with the KCNQ1 channel to modulate I(Ks) current amplitude and gating kinetics. Other LQT5 mutations in this region share the Y81C phenotype and probably affect the I(Ks) channel function by a similar mechanism.