There is experimental evidence that the astaxanthin, betanin, and epigallocatechin-3-gallate (EGCG) compounds slow down the aggregation kinetics and the toxicity of the amyloid-β (Aβ) peptide. How ...these inhibitors affect the self-assembly at the atomic level remains elusive. To address this issue, we have performed for each ligand atomistic replica exchange molecular dynamic (REMD) simulations in an explicit solvent of the Aβ11–40 trimer from the U-shape conformation and MD simulations starting from Aβ1–40 dimer and tetramer structures characterized by different intra- and interpeptide conformations. We find that the three ligands have similar binding free energies on small Aβ40 oligomers but very distinct transient binding sites that will affect the aggregation of larger assemblies and fibril elongation of the Aβ40 peptide.
This study examines effects of three friction models: a steady-state friction model (SS model), the LuGre model (LG model), and the revised LuGre model (RLG model) on the motion simulation accuracy ...of a pneumatic cylinder. An experimental set-up of an electro-pneumatic servo system is built, and characteristics of the piston position, the pressures in the two-cylinder chambers and the friction force are measured and calculated under different control inputs to the proportional flow control valves. Mathematical model of the electro-pneumatic servo system is derived, and simulations are carried out under the same conditions as the experiments. Comparisons between measured characteristics and simulated ones show that the RLG model can give the best agreement among the three friction models while the LG model can only simulate partly the stick-slip motion of the piston at low velocities. The comparison results also show that the SS model used in this study is unable to simulate the stick-slip motion as well as creates much oscillations in the friction force characteristics at low velocities.
Herein, a novel fluorescent sensor has been developed for the detection of biothiols based on theoretical calculations of the stability constant of the complex between a Cu2+ ion and ...(E)-3-((2-(benzodthiazol-2-yl)hydrazono)methyl)-7-(diethylamino) coumarin (BDC) as a fluorescent ligand. In this study, on the basis of density functional theory method, the Gibbs free energy of ligand-exchange reaction and the solvation model were carried out using thermodynamic cycles. The obtained results are in good agreement with the experimental data. The BDC–Cu2+ complex can be used as a fluorescent sensor for the detection of biothiols in the presence of non-thiol containing amino acids, with a detection limit for cysteine at 0.3 μM. Moreover, theoretical calculations of excited states were used to elucidate variations in the fluorescence properties. The computed results show that the excited doublet states D2 and D1 are dark doublet states, which quench the fluorescence of the complex.
Five hundred strains of rhizobacteria were isolated from the rhizosphere of the Central Highlands of Vietnam, where black pepper is cultivated. Of these, seven potent rhizobacteria were evaluated for ...anti-
Phytophthora
activity and 16S rRNA gene sequencing and phylogenic analysis classified. Evaluation of their antifungal activity was performed both in vitro and in vivo. The results showed that almost all potent rhizobacteria possessed anti-
Phytophthora
activity. The rhizobacteria strains displayed over 60% inhibition of
Phytophthora
during the in vitro test, and six rhizobacteria inhibited
Phytophthora
by 77.50–98.75% during the in vivo test. Enzymatic activities were measured to determine the antifungal mechanisms; these were identified as protease, chitinase, and
β
-glucanase. The effects of the rhizobacteria on plant growth and antifungal activity were also investigated. Under greenhouse conditions, black pepper seedlings treated with rhizobacteria were stronger and had lower rates of disease and fatality compared to the control group. The results from the in vitro test also showed that the anti-
Phytophthora
activity of the rhizobacteria was not dependent on enzyme activity, but rather on their chemical compounds. GC–MS and LC–MS profiles of the culture broth from the promising rhizobacteria strain RBDS.29 revealed seven potent antifungal compounds. The data suggest that
Bacillus velezensis
RB.DS29 is a promising rhizobacterium that promotes plant growth and the biocontrol of black pepper.
Genetic factors play an important role in the development of type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). However, few genetic association studies related to these disorders have ...been performed with Vietnamese subjects. In this study, the potential associations of
single nucleotide polymorphisms (SNPs) with T2DM and MetS in a Kinh Vietnamese population were investigated.
A study with 768 subjects was conducted to examine the associations of four
SNPs (rs266729, rs1501299, rs3774261, and rs822393) primarily with T2DM and secondarily with MetS. The TaqMan SNP genotyping assay was used to determine genotypes from subjects' DNA samples.
After statistical adjustment for age, sex, and body mass index, the
SNP rs266729 was found to be associated with increased risk of T2DM under multiple inheritance models: codominant (OR = 2.30, 95% CI = 1.16-4.58), recessive (OR = 2.17, 95% CI = 1.11-4.26), and log-additive (OR = 1.32, 95% CI = 1.02-1.70). However, rs1501299, rs3774261, and rs822393 were not associated with risk for T2DM. Additionally, rs266729, rs3774261, and rs822393 were statistically associated with MetS, while rs1501299 was not. Haplotype analysis showed a strong linkage disequilibrium between the SNP pairs rs266729/rs822393 and rs1501299/rs3774261, and the haplotype rs266729(G)/rs822393(T) was not statistically associated with MetS.
The results show that rs266729 is a lead candidate SNP associated with increased risk of developing T2DM and MetS in a Kinh Vietnamese population, while rs3774261 is associated with MetS only. Further functional characterization is needed to uncover the mechanism underlying the potential genotype-phenotype associations.
We investigated a strategy of exome sequencing DNA from the unaffected parents and applied a set of filtering criteria to identify genes where both partners are heterozygous for a potentially ...pathogenic variant.
We report a non-consanguineous couple who had three daughters, all spontaneous preterm birth at 36 weeks gestation and died in the first period after birth, suspected inborn errors of metabolism. Two days after birth, the first daughter presented with difficulty breathing, cyanosis and died; the second died at 33 days old; the third daughter was isolated under special care and was taken to the mother's room, developed the same symptoms and died after 5 days. Dried blood spot testing screen of 55 congenital metabolic disorders was negative.
Heterogenous variant in SLC25A20 gene was found in both parents, contributing to the delineations of the neonatal phenotypes related to SLC25A20 mutation in CACTD.
We investigated whether ginsenoside Re (Re) modulates phencyclidine (PCP)-induced sociability deficits and recognition memory impairments to extend our recent finding. We examined the role of GPx-1 ...gene in the pharmacological activity of Re against mitochondrial dysfunction induced by PCP in the dorsolateral cortex of mice. Since mitochondrial oxidative stress activates NADPH oxidase (PHOX), we applied PHOX inhibitor apocynin for evaluating interactive modulation between GPx-1 and PHOX against PCP neurotoxicity. Sociability deficits and recognition memory impairments induced by PCP were more pronounced in GPx-1 knockout (KO) than in wild type (WT) mice. PCP-induced mitochondrial oxidative stress, mitochondrial dysfunction, and membrane translocation of p47phox were more evident in GPx-1 KO than in WT. Re treatment significantly attenuated PCP-induced neurotoxic changes. Re also significantly attenuated PCP-induced sociability deficits and recognition memory impairments. The attenuation by Re was comparable to that by apocynin. The attenuation was more obvious in GPx-1 KO than in WT. Importantly, apocynin did not show any additional positive effects on the neuroprotective activity of Re, indicating that PHOX is a molecular target for therapeutic activity of Re. Our results suggest that Re requires interactive modulation between GPx activity and PHOX (p47phox) to exhibit neuroprotective potentials against PCP insult.
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•Genetic depletion of GPx-1 facilitates PCP-induced mitochondrial dysfunction, oxidative parameters and PHOX activity.•Genetic depletion of GPx-1 facilitates sociability deficits and recognition memory impairments induced by PCP.•Re-mediated protective potentials against PCP required the interactive modulation between GPx-1 and PHOX (p47phox).
Aim
This study assessed the Streptococcus pneumoniae colonisation rate and susceptibility to antibiotics among preschool children in rural Vietnam.
Method
Nasopharyngeal samples were collected from ...546 preschool children aged 6–59 months living in 460 households in the rural BaVi District of Hanoi and their main caregivers completed questionnaires. The samples were cultured, and the Streptococcus pneumoniae colonisation rate and antibiotic susceptibility were investigated. Resistance data from this 2014 study were compared with studies in 1999 and 2007, to identify 15‐year trends, together with clinical isolates from a national surveillance system of 16 Vietnamese hospital laboratories established in 2013.
Results
We found that 221/546 (40%) of the cultures were positive for Streptococcus pneumoniae. The susceptibility rates were trimethoprim‐sulphamethoxazole (5%), erythromycin (8%), ciprofloxacin (12%), benzyl‐penicillin (35%), tetracycline (49%), cefotaxime (55%), moxifloxacin (99%) and vancomycin (99%). All the susceptibility rates were lower in 2014 than 1999 and 2007, except tetracycline. Multi‐drug resistance was 80% in 2014, compared to 60% in 2007 and 31% in 1999. Antibiotics was reported used by 191 (35%) within one month, mainly cephalosporins 86 (45%), amoxycillin/ampicillin 69 (36%) and macrolides 30 (16%).
Conclusion
Streptococcus pneumoniae showed remarkable high resistance to commonly used antibiotics, including cephalosporins. Multi‐drug resistance rose from 31% to 80% during the 15‐year study period.
Pathogenic variants in the
gene are associated with two distinct autosomal recessive neuromuscular disorders: spinal muscular atrophy with respiratory distress type 1 (SMARD1; OMIM #604320) and ...Charcot-Marie-Tooth type 2S (CMT2S; OMIM #616155). SMARD1 is a severe and fatal condition characterized by infantile-onset respiratory distress, diaphragmatic palsy, and distal muscular weakness, while CMT2S follows a milder clinical course, with slowly progressive distal muscle weakness and sensory loss, without manifestations of respiratory disorder.
Whole-exome sequencing of the
gene was performed for eight Vietnamese patients with
-related neuromuscular disorders including five patients with SMARD1 and the others with CMT2S.
We identified one novel
variant c.1574T > C (p.Leu525Pro) in a SMARD1 patient. Besides that, two patients shared the same pathogenic variants (c.1235 + 3A > G/c.1334A > C) but presented completely different clinical courses: one with SMARD1 who deceased at 8 months of age, the other with CMT2S was alive at 3 years old without any respiratory distress.
This study is the first to report
-related neuromuscular disorders in Vietnam. A novel
variant c.1574T > C (p.Leu525Pro) expressing SMARD1 phenotype was detected. The presence of three patients with the same genotype but distinct clinical outcomes suggested the interaction of variants and other factors including relating modified genes in the mechanism of various phenotypes.
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