44 research outputs found
Molecular phylogeny of Annonaceae species from Binh Chau-Phuoc Buu Nature Reserve based on two chloroplast gene regions
In this study, based on molecular biology techniques, the matK and trnL-F regions of ten Annonaceae species grown in Binh Chau-Phuoc Buu Nature Reserve, Vietnam were successfully amplified and sequenced for the first time. Along with other highly homologous DNA sequences from the GenBank database, the molecular phylogeny of ten studied species was also established. By using the alignment tool of NCBI database, the percentage of identity among sequences of studied species was also presented. The study aims to partially contribute to the further understanding of the evolutionary relationships among Annonaceae species
Molecular identification of three Habenaria species from Binh Chau-Phuoc Buu Nature Reserve, Vietnam
The present provides molecular data for species of Habenaria diphylla (Nimmo) Dalzell, H. khasiana Hook.f. and H. rostellifera Rchb.f. collected from Binh Chau-Phuoc Buu Nature Reserve, Vietnam for the first time. Along with other DNA sequences from GenBank database, the phylogenetic trees for Habenaria species from Vietnam have been established
Habenaria diphylla (Nimmo) Dalzell (Orchidaceae), new record for the flora of Vietnam
Habenaria diphylla (Nimmo) Dalzell is reported for the first time as a new discovery for the flora of Vietnam based on the specimens collected in Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province. The present study provided the detailed characteristics of the species including detailed photographs of the morphological characteristics, the cross section of the leaf, inflorescence axis and root. Furthermore, the information about the species, including distribution, habitat, ecology and conservation status were also provided
Chemical profiles and biological activities of acetone extracts of nine Annonaceae plants
This study investigated the chemical components and bioactivities of acetone leaf extracts of nine Annonaceae plants collected in the Binh Chau-Phuoc Buu Nature Reserve, Vietnam. A total of 182 constituents were identified, with linolenic acid, diaeudesmin, germacrene D, 1-octadecenoic acid, 8-(3-octyl-2-oxiranyl)-1-octanol, oleic acid, and phenylmethyl ester being the major compounds. The antimicrobial activity of the extracts was evaluated using a disc diffusion assay. Eight of the nine extracts, except for the Mitrephora thorelii extract, showed an inhibition effect against Bacillus cereus and Staphylococcus aureus. The antioxidant activity of the extracts was determined using DPPH assay, and the cytotoxic activity was deter mined using SRB assay. The results showed that the acetone extracts of Artabotrys hexapetalus, Uvularia grandiflora, Polyalthia luensis, Xylopia pierrei, Sphaerocoryne affinis, Desmos cochinchinensis, Uvaria littoralis, Mitrephora thorelii, and Goniothalamus touranensis had significant activity with IC50 for the DPPH radical scavenging activity ranging from 18.56 to 702.33 μg/mL, and the IC50 for the cytotoxic effects ranged from 5.39 to 251.77 μg/mL. Overall, the results obtained provide experimental evidence for the potential use of these plants in medicine and other related fields
Chemical Components of Essential Oils From the Leaves of Seven Species Belonging to Rutaceae Family from Binh Chau-Phuoc Buu Nature Reserve, Vietnam
Several plant species of the Rutaceae family are medicinal plants, oil bearing and food crops. To provide more information for utilization of some species of this family in Binh Chau-Phuoc Buu Nature Reserve, we extracted essential oils from the leaves of seven species of the Rutaceae family: Acronychia pedunculata (L.) Miq., Atalantia citroides Pierre ex Guillaumin, Clausena excavata Burm.f., Glycosmis pentaphylla (Retz.) DC., Luvunga scandens (Roxb.) Buch.-Ham. ex Wight & Arn, Melicope pteleifolia (Champ. ex Benth.) T.G. Hartley, and Micromelum sp., via hydrodistillation, and identified their components using GC/MS analysis. A total of 60 compounds were identified from essential oils of seven species. The main components of the essential oils isolated from five species, including A. pedunculata, C. excavata, M. pteleifolia, G. pentaphylla, and Micromelum sp., were caryophyllene (57.63% and 55.41% in A. pedunculata and C. excavata, respectively), 1,9-decadiyne (32.59%, M. pteleifolia), β-ocimene (23.10%, G. pentaphylla), and 3-carene (58.03%, Micromelum sp.). Additionally, this study revealed the chemical composition of essential oils of L. scandens and A. citroides for the first time. The main constituent of A. citroides was 7-oxabicyclo[4.1.0] heptane, 3-oxiranyl- (53.91%) and that of L. scandens was caryophyllene (34.66%). These findings provide the basis for further application of these species in medicine
Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021
We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions
Лексические средства связности в речи телеведущего в жанре интерактивной белорусскоязычной телебеседы
Материалы XII Междунар. науч. конф. студентов, магистрантов, аспирантов и молодых ученых, Гомель, 16–17 мая 2019 г
Expansion of KPC-producing Enterobacterales in four large hospitals in Hanoi, Vietnam
Objectives
: The incidence of carbapenem resistance among nosocomial Gram-negative bacteria in Vietnam is high and increasing, including among Enterobacterales. In this study, we assessed the presence of one of the main carbapenemase genes, blaKPC, among carbapenem-resistant Enterobacterales (CRE) from four large hospitals in Hanoi, Vietnam, between 2010 and 2015, and described their key molecular characteristics.
Methods
: KPC-producing Enterobacterales were detected using conventional PCR and were further analysed using S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), Southern blotting and whole-genome sequencing (WGS) for sequence typing and genetic characterisation.
Results
: blaKPC genes were detected in 122 (20.4%) of 599 CRE isolates. blaKPC-carrying plasmids were diverse in size. Klebsiella pneumoniae harbouring blaKPC genes belonged to ST15 and ST11, whereas KPC-producing Escherichia coli showed more diverse sequence types including ST3580, ST448, ST709 and ST405. Genotypic relationships supported the hypothesis of circulation of a population of ‘resident’ resistant bacteria in one hospital through the years and of transmission among these hospitals via patient transfer. WGS results revealed co-carriage of several other antimicrobial resistance genes and three different genetic contexts of blaKPC-2. Among these, the combination of ISEcp1–blaCTX-M and ISKpn27–blaKPC–ΔISKpn6 on the same plasmid is reported for the first time.
Conclusion
: We describe the dissemination of blaKPC-expressing Enterobacterales in four large hospitals in Hanoi, Vietnam, since 2010, which may have started earlier, along with their resistance patterns, sequence types, genotypic relationship, plasmid sizes and genetic context, thereby contributing to the overall picture of the antimicrobial resistance situation in Enterobacterales in Vietnam
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
Histamine Derived from Probiotic Lactobacillus reuteri Suppresses TNF via Modulation of PKA and ERK Signaling
Beneficial microbes and probiotic species, such as Lactobacillus reuteri, produce biologically active compounds that can modulate host mucosal immunity. Previously, immunomodulatory factors secreted by L. reuteri ATCC PTA 6475 were unknown. A combined metabolomics and bacterial genetics strategy was utilized to identify small compound(s) produced by L. reuteri that were TNF-inhibitory. Hydrophilic interaction liquid chromatography-high performance liquid chromatography (HILIC-HPLC) separation isolated TNF-inhibitory compounds, and HILIC-HPLC fraction composition was determined by NMR and mass spectrometry analyses. Histamine was identified and quantified in TNF-inhibitory HILIC-HPLC fractions. Histamine is produced from L-histidine via histidine decarboxylase by some fermentative bacteria including lactobacilli. Targeted mutagenesis of each gene present in the histidine decarboxylase gene cluster in L. reuteri 6475 demonstrated the involvement of histidine decarboxylase pyruvoyl type A (hdcA), histidine/histamine antiporter (hdcP), and hdcB in production of the TNF-inhibitory factor. The mechanism of TNF inhibition by L. reuteri-derived histamine was investigated using Toll-like receptor 2 (TLR2)-activated human monocytoid cells. Bacterial histamine suppressed TNF production via activation of the H2 receptor. Histamine from L. reuteri 6475 stimulated increased levels of cAMP, which inhibited downstream MEK/ERK MAPK signaling via protein kinase A (PKA) and resulted in suppression of TNF production by transcriptional regulation. In summary, a component of the gut microbiome, L. reuteri, is able to convert a dietary component, L-histidine, into an immunoregulatory signal, histamine, which suppresses pro-inflammatory TNF production. The identification of bacterial bioactive metabolites and their corresponding mechanisms of action with respect to immunomodulation may lead to improved anti-inflammatory strategies for chronic immune-mediated diseases