Background. Trypanosoma is a genus of unicellular parasitic flagellate protozoa. Trypanosoma brucei species and Trypanosoma cruzi are the major agents of human trypanosomiasis; other Trypanosoma ...species can cause human disease, but are rare. In March 2015, a 38-year-old woman presented to a healthcare facility in southern Vietnam with fever, headache, and arthralgia. Microscopic examination of blood revealed infection with Trypanosoma. Methods. Microscopic observation, polymerase chain reaction (PCR) amplification of blood samples, and serological testing were performed to identify the infecting species. The patient's blood was screened for the trypanocidal protein apolipoprotein L1 (APOL1), and a field investigation was performed to identify the zoonotic source. Results. PCR amplification and serological testing identified the infecting species as Trypanosoma evansi. Despite relapsing 6 weeks after completing amphotericin B therapy, the patient made a complete recovery after 5 weeks of suramin. The patient was found to have 2 wild-type APOL1 alleles and a normal serum APOL1 concentration. After responsive animal sampling in the presumed location of exposure, cattle and/or buffalo were determined to be the most likely source of the infection, with 14 of 30 (47%) animal blood samples testing PCR positive for T. evansi. Conclusions. We report the first laboratory-confirmed case of T. evansi in a previously healthy individual without APOL1 deficiency, potentially contracted via a wound while butchering raw beef, and successfully treated with suramin. A linked epidemiological investigation revealed widespread and previously unidentified burden of T. evansi in local cattle, highlighting the need for surveillance of this infection in animals and the possibility of further human cases.
We used stochastic frontier analysis (SFA) to investigate the cost efficiency and productivity of the manufacturing sector in Vietnam from 2010 to 2016 to determine the sources of their performance. ...Our findings suggest that it is important for the country and its regions to create a competitive environment for the development of their local manufacturing firms. We also found that larger firms, those with a longer history and those that are more export-oriented tend to outperform their counterparts. We suggest that the sampled firms should focus more on research and development and technological implementation to shift towards a capital-intensive state and thus enhance their productivity.
The goal of the present study was to formulate and evaluate a topical gel of nanoparticulate andrographolide for the anti-bacterial and inflammation effect that would attenuate the first-pass ...metabolism following oral administration. Nanoparticulate andrographolide was fabricated by the solvent evaporation method and optimized using size, polydispersity index, and physical stability properties. The dispersion was converted into a dermal gel using three gelling agents. The optimal gel formulation based on Carbopol 934 at 0.25% concentration showed four-fold higher drug release through a mouse skin model and 26-fold higher drug retention in the skin compared to the gel formulation containing saturated suspension. The anti-inflammation activity of andrographolide suggests also that the topical gel as a promising dosage form for dermal delivery of poorly water-soluble and extensively metabolized andrographolide.
The use of copper nanoparticles for the inhibition of plant pathogens
, which causes wilt disease, and
, which causes citrus canker, was investigated in this study. To avoid the inhibiting effect of ...Cu
ions on the bacterial cells, the copper nanoparticles were synthesized in the cathode chamber of a non-external circuit bioelectrochemical system (nec_BES) inoculated with
sp. HN-41 at the anode. The electrons produced by the oxidation of lactate by
sp. HN-41 were directly transferred to the anolyte in the cathode
a graphite electrode connecting the anode and cathode chambers. SEM images of the produced particles revealed that the copper nanoparticles were aggregated into spherical shapes with an average size of 2.9 μm from smaller particles with a size range from 30 nm to approximately 190 nm. X-ray diffraction demonstrated that the copper nanoparticles were mainly in the form of a single-phase crystal mixture of atacamite (Cu
Cl(OH)
) and paracatamite (Cu
Cl(OH)
). Finally, for the application of synthesized nanoparticles, an agar diffusion test was applied to assess the antibacterial activity of the formed copper nanoparticles in propylene glycol solvent against
and
. The results showed that the nanoparticles damaged the cells of
, with a half maximum inhibition (IC
) value of 42 ppm, but did not damage
cells.
Phytopathogenic fungi and bacteria pose a threat to plant health and cause large losses in crop quality and production. Currently, green methods for controlling phytopathogenic fungi and bacteria ...have been paid attention to. In this study, in vitro and in vivo antimicrobial activities of Desmodium styracifolium and its metabolites against phytopathogenic fungi and bacteria were investigated to find a new solution for the green method. The result showed the crude extract of D. styracifolium exerts a potent suppression against fungal plant diseases in vivo. At 3000 µg/mL, n-hexane and dichloromethane-soluble extracts of D. styracifolium effectively controlled rice blast (84.6% and 53.8%) and tomato late blight (67.7% and 61.3%), respectively. Using in vitro antifungal bioassay-guided fractionation, sixteen compounds were isolated and identified. The occurrence of isoflavanones 5 and 7 in D. styracifolium, as well as pyrrole lactone alkaloid 14 in the genus Desmodium was firstly reported. Compound 9, a new isoflavone isolated from nature, displayed potent antifungal and antibacterial activities in vitro. The two remarkable bioactive groups of isoflavanones (5–7) and isoflavones (8–10) were determined as antifungal constituents from D. styracifolium with a wide-spectrum antifungal activity. Magnaporthe oryzae and Phytophthora species were susceptible to the isoflavonoid groups. Especially, in a range of 125–500 µg/mL, isoflavonoids 5 and 10 effectively inhibited M. oryzae in both in vitro and in vivo experiments. Compounds 5, 6, 8–11 significantly suppressed the bacterial growth of Acidovorax avenae subsp. cattlyae in vitro. Among them, 5 (IC50 = 33.1 µg/mL) and 9 (IC50 = 42.2 µg/mL) were the best inhibitors against A. avenae subsp. cattlyae. Our findings indicate that the isoflavanones and isoflavones of D. styracifolium are worthy of further consideration as lead molecules to develop a new class of inhibitors against phytopathogenic fungi and bacteria.
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•The extracts of Desmodium styracifolium effectively suppressed various fungal plant pathogens in vitro and in vivo.•A new antimicrobial isoflavone 5,7,3′-trihydroxy-4′,5′-dimethoxyisoflavone (9) was isolated from nature.•Isoflavonoids of D. styracifolium inhibited Magnaporthe oryzae and oomycetes and bacterium Acidovorax avenae subsp. cattlyae.•Isoflavonoids 5 and 10 suppressed M. oryzae in both in vitro and in vivo bioassays.•Compounds 5 and 9 were potent inhibitors against A. avenae subsp. cattlyae.
The synthesis of CdS nanoparticles was developed based on the unconventional design of bioelectrochemical system (BES) inoculated with Shewanella sp. HN-41. The BES configuration included two bottle ...chambers separated by silicon membrane but directly connected by a graphite electrode perforating through silicon membrane, namely, non-external circuit bioelectrochemical system (nec_BES). Shewanella sp. HN-41 in the anode of nec_BES consumed lactate and transferred electrons to the graphite electrode end in the anode and, in its turn, the graphite electrode end in the cathode reduced directly thiosulfate to sulphide, forming CdS nanoparticles after 21 days. CdS nanoparticles with the average size of approximately 17 nm were synthesized in the cathode solution. The hollow, spherical, and void structure of particles was observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images. The energy dispersive X-ray spectroscopy (EDS) study confirmed the nanoparticles contained Cd and S elements, and X-ray diffraction (XRD) data showed a strong crystalline phase and mixed crystallites of CdS nanoparticles. The UV-Vis absorption spectra of CdS nanoparticles revealed the blue shift in excitonic transition with respect to CdS bulk material, suggesting its potential application in optical studies. The bioelectrochemical system can be applied for the removal and preparation of other sulphide heavy metals.
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Synthesis of selenium nanoparticles from selenite by Shewanella sp. HN-41 demonstrated that particle size depended on the reaction time and biomass of cells. The slow reaction and low ...biomass tended to form small particles. In this study, Shewanella sp. HN-41 was introduced into the anode of a nonexternal circuit bioelectrochemical system (nec_BES) to convert chemical energy from lactate to low electron current to the cathode, where selenite was reduced.
Our experiment with two systems, one bioelectrochemical system with a cathode flushed with nitrogen and the other with a no-nitrogen-flushing cathode, showed that the former could not produce Se nanoparticles after 21 d, but the latter formed them with an average size of 37.7 nm. The SEM and TEM images demonstrated that the particle size of 10 nm occupied over 10% and most of the particles were in the range of 30–60 nm. The XRD result and SAED image demonstrated no clear peaks of crystal and proved that the Se nanoparticles are amorphous.
The clean Se nanoparticles were synthesized and completely separated from bacterial cells in the bioelectrochemical system. This study opened a new approach for the biological synthesis of metal nanoparticles. Finally, the Se products in the range of 30–60 nm can be tested for antimicrobial activities in medical applications.
How to cite: Ho CT, Nguyen T-H, Lam T-T, et al. Biogenic synthesis of selenium nanoparticles by Shewanella sp. HN-41 using a modified bioelectrochemical system. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.07.004
Vietnam has a high thalassemia burden. We collected blood samples from 5880 pregnant Vietnamese women during prenatal health checks to assess thalassemia carrier frequency using combined ...gap-polymerase chain reaction (gap-PCR) and targeted next-generation sequencing (NGS). Thalassemia carriers were identified with prevalence of 13.13% (772), including 7.82% (460) carriers of α-thalassemia (α-thal), 5.31% (312) carriers of β-thalassemia (β-thal), and 0.63% (37) concurrent α-/β-thal carriers. Deletional mutations (368) accounted for 80.0% of α-thal carriers, of which, --
SEA
(Southeast Asian) (n = 254; 55.0%) was most prevalent, followed by the -α
3.7
(rightward) (n = 66; 14.0%) and -α
4.2
(leftward) (n = 45; 9.8%) deletions. Hb Westmead (HBA2: c.369C>G) (n = 53) and Hb Constant Spring (Hb CS or HBA2: c.427T>C) (in 28) are the two most common nondeletional α-globin variants, accounting for 11.5 and 6.0% of α-thal carriers. We detected 11 different β-thal genotypes. Hb E (HBB: c.79G>A) (in 211) accounted for 67.6% of β-thal carriers. The most common β-thal genotypes were associated with mutations at codon 17 (A>T) (HBB: c.52A>T), codons 41/42 (-TTCT) (HBB: c.126_129delCTTT), and codon 71/72 (+A) (HBB: c.217_218insA) (prevalence 0.70%, 0.68%, and 0.2%, respectively). Based on mutation frequencies calculated in this study, estimates of 5021 babies in Vietnam are affected with clinically severe thalassemia annually. Our data suggest a higher thalassemia carrier frequency in Vietnam than previously reported. We established that combining NGS with gap-PCR creates an effective large-scale thalassemia screening method that can detect a broad range of mutations.
Avocado is a significant cash crop in Vietnam, while little is known about its genetic diversification. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers were ...performed to investigate the genetic diversity of twenty-eight imported and domestic avocado cultivars being maintained at Western Highlands Agriculture and Forestry Science Institute, Dak Lak, Vietnam. 18 RAPD and 15 ISSR primers produced 3183 and 2807 scorable bands, of which 83.92% and 71.72% were polymorphic, respectively. The RAPD markers exhibited an average PIC of 0.27 and Rp index of 12.63 whereas the mean PIC and Rp values of ISSR primers were 0.21 and 13.37, respectively. The correlation between RAPD and ISSR markers was low (r = 0.338), suggesting that the ability to resolve genetic variation among varieties may relate to the number of detected polymorphisms rather than the marker employed. Nevertheless, the correlation between ISSR and combined data was high (r = 0.791) and the correlation between RAPD and combined matrices was even higher (r = 0.897). This indicates that RAPD markers have slightly higher efficiency over ISSR to resolve genetic variation among 28 avocado cultivars. High genetic diversity among 28 avocado cultivars was revealed with the Jaccard's similarity coefficient ranging from 0.623 to 0.913 based on combined data analysis. The UPGMA dendrogram generated from combined RAPD and ISSR data grouped Vietnamese domestic and imported avocado cultivars into three different groups at 72% similarity. These results could be applied to the avocado conservation and breeding programs.
We study the problem of evaluating the goodness of a kernel matrix for a classification task. As kernel matrix evaluation is usually used in other expensive procedures like feature and model ...selections, the goodness measure must be calculated efficiently. Most previous approaches are not efficient except for kernel target alignment (KTA) that can be calculated in
O
(
n
2
)
time complexity. Although KTA is widely used, we show that it has some serious drawbacks. We propose an efficient surrogate measure to evaluate the goodness of a kernel matrix based on the data distributions of classes in the feature space. The measure not only overcomes the limitations of KTA but also possesses other properties like invariance, efficiency and an error bound guarantee. Comparative experiments show that the measure is a good indication of the goodness of a kernel matrix.
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