Baseline susceptibility of Asian corn borer (Ostrinia furnacalis (Guenée)) populations in Vietnam to Cry1Ab insecticidal protein

Susceptibility of Asian corn borer (ACB), Ostrinia furnacalis (Guenée) to Bacillus thuringiensis (Bt) Cry1Ab protein was studied between 2015 and 2016 with 11 ACB populations, collected from various geographical regions in Vietnam. A concentration range of Cry1Ab from 0.20 to 26.10 ng/cm² of diet was evaluated against F₁ ACB neonates using diet surface-overlay bioassays. Mortality data was recorded daily until seven days after infestation. Growth inhibition was recorded at the end of seven days. The median lethal concentration (LC₅₀) varied ≈3-fold among the different populations, ranging from 0.58 to 1.83 ng/cm² of diet with an overall mean of 0.86 ng/cm² of diet. Even the lowest concentration of 0.20 ng/cm² caused 73.53% growth inhibition. >90% growth inhibition was achieved at 0.82 ng/cm² or higher concentrations. The results reflect natural variation in Bt susceptibility among ACB populations rather than variation caused by prior exposure to selection pressures. LC₉₉ value (17.26 ng/cm²) was generated by pooling mortality data across different populations. The upper fiducial limit of LC₉₉ (24.38 ng/cm²) could be a potential diagnostic dose for future resistance monitoring programs. The findings from this study suggest that ACB populations in Vietnam are highly susceptible to Cry1Ab protein. This is the first report of Cry1Ab susceptibility of different ACB populations in Vietnam and will serve as a baseline for future resistance monitoring work.     

Hepatoprotective Activity of Betulin and Dipterocarpol Derivatives

Russian Journal of Bioorganic Chemistry - The regioselective synthesis of betulin 3,28-bis- and 28-monoacylates (nicotinate and isonicotinates) as well as of 3β-hemisuccinyl dipterocarpol was...     

Evaluation of the MODS culture technique for the diagnosis of tuberculous meningitis

Background

Tuberculous meningitis (TBM) is a devastating condition. The rapid instigation of appropraite chemotherapy is vital to reduce morbidity and mortality. However rapid diagnosis remains elusive; smear microscopy has extremely low sensitivity on cerebrospinal fluid (CSF) in most laboratories and PCR requires expertise with advanced infrastructure and has sensitivity of only around 60% under optimal conditions. Neither technique allows for the microbiological isolation of M. tuberculosis and subsequent drug susceptibility testing. We evaluated the recently developed microscopic observation drug susceptibility (MODS) assay format for speed and accuracy in diagnosing TBM.

Methodology/Principal Findings

Two hundred and thirty consecutive CSF samples collected from 156 patients clinically suspected of TBM on presentation at a tertiary referal hospital in Vietnam were enrolled into the study over a five month period and tested by Ziehl-Neelsen (ZN) smear, MODS, Mycobacterial growth Indicator tube (MGIT) and Lowenstein-Jensen (LJ) culture. Sixty-one samples were from patients already on TB therapy for >1day and 19 samples were excluded due to untraceable patient records. One hundred and fifty samples from 137 newly presenting patients remained. Forty-two percent (n = 57/137) of patients were deemed to have TBM by clinical diagnostic and microbiological criteria (excluding MODS). Sensitivity by patient against clinical gold standard for ZN smear, MODS MGIT and LJ were 52.6%, 64.9%, 70.2% and 70.2%, respectively. Specificity of all microbiological techniques was 100%. Positive and negative predictive values for MODS were 100% and 78.7%, respectively for HIV infected patients and 100% and 82.1% for HIV negative patients. The median time to positive was 6 days (interquartile range 5–7), significantly faster than MGIT at 15.5 days (interquartile range 12–24), and LJ at 24 days (interquartile range 18–35 days) (P<0.01).

Conclusions

We have shown MODS to be a sensitive, rapid technique for the diagnosis of TBM with high sensitivity, ease of performance and low cost (0.53 USD/sample).     

Simultaneous quantification of voriconazole and posaconazole in human plasma by high-performance liquid chromatography with ultra-violet detection

A sensitive and selective high-performance liquid chromatographic (HPLC) method with ultra-violet detection has been developed and validated for the simultaneous determination of posaconazole and voriconazole, two systemic anti-fungal agents. An internal standard diazepam was added to 100 microL of human plasma followed by 3 mL of hexane-methylene chloride (70:30, v/v). The organic layer was evaporated to dryness and the residue was reconstituted with 100 microL of mobile phase before being injected in the chromatographic system. The compounds were separated on a C8 column using sodium potassium phosphate buffer (0.04 M, pH 6.0): acetonitrile:ultrapure water (45:52.5:2.5, v/v/v) as mobile phase. All compounds were detected at a wavelength of 255 nm. The assay was linear and validated over the range 0.2-10.0 mg/L for voriconazole and 0.05-10.0 mg/L for posaconazole. The biases were comprised between -3 and 5% for voriconazole and -2 and 8% for posaconazole. The intra- and inter-day precisions of the method were lower than 8% for the routine quality control (QC). The mean recovery was 98% for voriconazole and 108% for posaconazole. This method provides a useful tool for therapeutic drug monitoring.     

Syntenin-1-mediated small extracellular vesicles promotes cell growth,migration, and angiogenesis by increasing onco-miRNAs secretion in lung cancer cells

Small extracellular vesicles (sEVs) play a pivotal role in tumor progression by mediating intercellular communication in the tumor microenvironment (TME). Syntenin-1 induces malignant tumor progression in various types of human cancers, including human lung cancer and regulates biogenesis of sEVs. However, the function of syntenin-1-regulated sEVs and miRNAs in sEVs remains to be elucidated. In the present study, we aimed to demonstrate the role of oncogenic Ras/syntenin-1 axis in the release of sEVs and elucidate the function of syntenin-1-mediated miRNAs in sEVs in lung cancer progression. The results revealed that oncogenic Ras promoted the release of sEVs by inducing syntenin-1 expression; disruption of syntenin-1 expression impaired the release of sEVs as well as sEV-mediated cancer cell migration and angiogenesis. Moreover, we identified three miRNAs, namely miR-181a, miR-425-5p, and miR-494-3p, as onco-miRNAs loaded into syntenin-1-dependent sEVs. Remarkably, miR-494-3p was highly abundant in sEVs and its release was triggered by syntenin-1 expression and oncogenic Ras. Ectopic expression of the miR-494-3p mimic enhanced the migration and proliferation of lung cancer cells as well as tube formation in endothelial cells; however, the miR-494-3p inhibitor blocked sEV-mediated effects by targeting tyrosine-protein phosphatase nonreceptor type 12 (PTPN12), a tumor suppressor. sEVs promoted tumor growth and angiogenesis by downregulating PTPN12 expression; however, the miR-494-3p inhibitor significantly suppressed these effects in vivo, confirming that miR-494-3p acts as a major onco-miRNA loaded into lung cancer cell-derived sEVs. Eventually, the oncogenic Ras/syntenin-1 axis may induce cancer progression by increasing miR-494-3p loading into sEVs in lung cancer cells in the TME.Subject terms: Cancer microenvironment, Non-small-cell lung cancer, Oncogenesis     

Buffers for the reconstitution of aspartate aminotransferase

The cofactor activation of the apoenzyme of pig heart cytosolic aspartate aminotransferase was studied in various buffers. Cationic buffers are shown to allow maximal reconstitution in the pH range of 5.0 to 9.0. Anionic buffers made up of mono- and dicarboxylates are found to affect reconstitution in a pH-dependent manner. At low pH, the carboxylates strongly inhibit reconstitution, but at high pH, they show less effect. In contrast, the more potent inhibitor Pi shows the opposite pH profile. Dicarboxylates are considerably more inhibitory than monocarboxylates. Substantial protection against inhibition by a number of carboxylates may be achieved by the addition of sodium chloride.     

Analysis of a Major Phenolic Glucoside and Biochemistry Compounds from Curculigo Orchioides Gaertn

Background:Orcinol-β-D-glucoside, which is also known as orcinol glucoside, is a major phenolic glucoside compound in the rhizome of the Curculigo orchioides Gaertn. This compound has many medicinal properties such as being antioxidant, immunomodulatory, antiosteoporosis, stress relief, antidepressant, etc.Methods:Determination of reducing sugar content by Bertrand’s method, determination of lipid content by Soxhlet method, determination of vitamin C content by iodine titration, determination of enzyme activity catalase by titration with KMnO4. Quantification of Orcinol-β-D-glucoside was conducted by HPLC analysis.Results:The Orcinol-β-D-glucoside of C. orchioides in Thuy Bang mountain was highest. Besides, the content of reducing sugars, vitamin C, enzyme catalase, and lipids of C. orchioides differed significantly among sites. In which, the reducing sugar and vitamin C of C. orchioides in Ngu Binh mountain was highest. Whereas, enzyme catalase was also highest in Thuy Bang mountain. However, the lipid content of C. orchioides was also highest in Huong Tho mountain.Conclusion:The result will contribute to providing the scientific basis for the selection of breeding, planting, development of C. orchioides in Thua Thien Hue province, as well as other provinces in Vietnam and opening new research directions for applications in the future.Key Words: Antioxidants, Hypoxidaceae, Medicinal Plants, Vietnam     

Homoisoflavonoids from Ophiopogon japonicus Ker-Gawler

From the ethyl acetate extract of the tuberous roots of Ophiopogon japonicus (Liliaceae) eight known and five new homoisoflavonoidal compounds were isolated. The new compounds are 5,7-dihydroxy-8-methoxy-6-methyl-3-(2'-hydroxy-4'-methoxybenzyl)chroman-4-one (1), 7-hydroxy-5,8-dimethoxy-6-methyl-3-(2'-hydroxy-4'-methoxybenzyl)chroman-4-one (2), 5,7-dihydroxy-6,8-dimethyl-3-(4'-hydroxy-3'-methoxybenzyl)chroman-4-one (3), 2,5,7-trihydroxy-6,8-dimethyl-3-(3',4'-methylenedioxybenzyl)chroman-4-one (4) and 2,5,7-trihydroxy-6,8-dimethyl-3-(4'-methoxybenzyl)chroman-4-one (5). Their structures have been elucidated by mass and NMR spectroscopy. Compounds 4 and 5 are the first isolated homoisoflavonoids with a hemiacetal function at position 2.     

Effects of acylation on the structure,lipid binding,and transfer activity of wheat lipid transfer protein

Study of the effect of protein chemical acylation on their functional properties or activity often brings valuable information regarding structure-function relationships. We performed such work on wheat lipid transfer protein, LTP1, to investigate the role of grafted acyl chains on the lipid binding and transfer properties. LTP1 was acylated by using anhydride derivatives of various chain lengths from C2 to C6. Only the chemical modifications with hexanoic acid yielded a marked effect on the tertiary structure and a slight change in the secondary structure. The affinity of the modified proteins for myristoyl-lysophosphatidylcholine was similar to that of the native protein accompanied by a slight decrease in stoichiometry. Interestingly, the acylation of LTP1 enhanced the lipid transfer activity by at least a factor of 10 for hexanoic chain length. Finally, the grafting of acyl chains was investigated by means of molecular modelling, and an attempt is made to correlate with our experimental data.