Severe fever with thrombocytopenia syndrome is a tick-borne viral disease, with a high mortality rate that was first reported in China in 2009. Scrub typhus is an acute febrile illness caused by
, a ...bacterium transmitted to humans through chigger mite bites. Severe fever with thrombocytopenia syndrome and scrub typhus are endemic to South Korea. To investigate evidence of severe fever with thrombocytopenia syndrome virus (SFTSV) infection or mixed infection with scrub typhus in South Korea, we examined 2,329 sera samples collected from patients presenting from November 1, 2000, to November 1, 2003, for the diagnosis of rickettisal diseases at Seoul National University, Seoul, South Korea. We found retrospective evidence of SFTSV infection or mixed infection with scrub typhus in South Korea in 2000-2003. Severe fever with thrombocytopenia syndrome virus infections in South Korea occurred before previously reported cases and were more concurrent with those in China. It is important to consider SFTSV infection in patients with scrub typhus.
Sediment bioelectrochemical systems (SBESs) can be integrated into brackish aquaculture ponds for
bioremediation of the pond water and sediment. Such an
system offers advantages including reduced ...treatment cost, reusability and simple handling. In order to realize such an application potential of the SBES, in this laboratory-scale study we investigated the effect of several controllable and uncontrollable operational factors on the
bioremediation performance of a tank model of a brackish aquaculture pond, into which a SBES was integrated, in comparison with a natural degradation control model. The performance was evaluated in terms of electricity generation by the SBES, Chemical oxygen demand (COD) removal and nitrogen removal of both the tank water and the tank sediment. Real-life conditions of the operational parameters were also experimented to understand the most close-to-practice responses of the system to their changes. Predictable effects of controllable parameters including external resistance and electrode spacing, similar to those reported previously for the BESs, were shown by the results but exceptions were observed. Accordingly, while increasing the electrode spacing reduced the current densities but generally improved COD and nitrogen removal, increasing the external resistance could result in decreased COD removal but also increased nitrogen removal and decreased current densities. However, maximum electricity generation and COD removal efficiency difference of the SBES (versus the control) could be reached with an external resistance of 100 Ω, not with the lowest one of 10 Ω. The effects of uncontrollable parameters such as ambient temperature, salinity and pH of the pond (tank) water were rather unpredictable. Temperatures higher than 35°C seemed to have more accelaration effect on natural degradation than on bioelectrochemical processes. Changing salinity seriously changed the electricity generation but did not clearly affect the bioremediation performance of the SBES, although at 2.5% salinity the SBES displayed a significantly more efficient removal of nitrogen in the water, compared to the control. Variation of pH to practically extreme levels (5.5 and 8.8) led to increased electricity generations but poorer performances of the SBES (vs. the control) in removing COD and nitrogen. Altogether, the results suggest some distinct responses of the SBES under brackish conditions and imply that COD removal and nitrogen removal in the system are not completely linked to bioelectrochemical processes but electrochemically enriched bacteria can still perform nonbioelectrochemical COD and nitrogen removals more efficiently than natural ones. The results confirm the application potential of the SBES in brackish aquaculture bioremediation and help propose efficient practices to warrant the success of such application in real-life scenarios.
Iron-oxidizing bacterial consortia can be enriched in microbial fuel cells (MFCs) operated with ferrous iron as the sole electron donor. In this study, we investigated the possibility of using such ...lithotrophic iron-oxidizing MFC (LIO-MFC) systems as biosensors to monitor iron and manganese in water samples. When operated with anolytes containing only ferrous iron as the sole electron donor, the experimented LIO-MFCs generated electrical currents in response to the presence of Fe(2+) in the anolytes. For the concentrations of Fe(2+) in the range of 3-20 mM, a linear correlation between the current and the concentration of Fe(2+) could be achieved (r(2) = 0.98). The LIO-MFCs also responded to the presence of Mn(2+) in the anolytes but only when the Mn(2+) concentration was less than 3 mM. The presence of other metal ions such as Ni(2+) or Pb(2+) in the anolytes reduced the Fe(2+)-associated electricity generation of the LIO-MFCs at various levels. Organic compounds, when present at a non-excessive level together with Fe(2+) in the anolytes, did not affect the generation of electricity, although the compounds might serve as alternative electron donors for the anode bacteria. The performance of the LIO-MFCs was also affected to different degrees by operational parameters, including surrounding temperature, pH of the sample, buffer strength and external resistance. The results proved the potential of LIO-MFCs as biosensors sensing Fe(2+) in water samples with a significant specificity. However, the operation of the system should be in compliance with an optimal procedure to ensure reliable performance.
Yen NTN, Chung DD, Hong NTK, Cham NP, Nhan VT, Linh DTL, Ngoc NLB, Thai NM, Nga ND, Anh NT. 2023. Isolation, phylogenetic analysis and bioprospection of myxobacteria from Vietnam. Biodiversitas 24: ...5653-5663. Myxobacteria have been considered microbial factories for producing secondary metabolites that have a variety of potential biological actions for discovering and isolating new biological molecules. Myxobacteria were isolated from soil samples collected in some provinces/cities in Vietnam. The purified isolates were identified based on morphology, biochemical test and phylogenetic analysis inferred from 16S rRNA gene. High-throughput screening assays including 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DDPH) for antioxidant properties and microdilution for antimicrobial activity were performed with myxobacterial extracts. Compounds from potential strain were predicted using liquid chromatography coupled with mass spectrometry. Forty-three myxobacterial strains were isolated and classified into seven genera of Angiococcus, Archangium, Chondromyces, Corallococcus, Cystobacter, Melittangium, and Myxococcus. The extract from CT21 strain had the highest total antioxidant activity (IC50 = 52.34 ± 1.47 and 30.28 ± 0.74 ?g/mL for the DPPH and ABTS, respectively). It is worth noting that all strains isolated myxobacterial strains show inhibitory activity against at least one of the tested microorganisms. The most potent antimicrobial strain was Myxococcus stipitatus GL41, which inhibited all tested microorganisms, and the minimal inhibitory concentration (MIC) values were 1 ?g/mL against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive Staphylococcus aureus (MSSA), Streptococcus faecalis, Candida albicans, and Aspergillus niger. Mass spectrometry analysis revealed the presence of althiomycin - the polyketide antibiotic from ethyl acetate fraction. In the present study, myxobacteria were isolated from soil sample collected from Vietnam, analyzed phylogenetically, and screened for biological activities.
Co-sensitizers and co-adsorbents are promising materials to enhance the light harvesting efficiency and reduce the un-expected back transfer reaction (recombination) of dye-sensitized solar cells ...(DSSCs). In this study, three sensitizers with triphenylamine as an electron donor, thiophene as a bridge and various numbers of acceptors/anchors cyanoacetic acid (TPA3T1A, TPA3T2A and TPA3T3A) were synthesized, and TPA3T1A and TPA3T2A were used as co-adsorbents with TPA3T3A. The results showed that co-adsorption on the TiO2 surface at the following percentages, TPA3T3A 73%, TPA3T1A 17% and TPA3T2A 10%, resulted in an increase in the photovoltaic performance of the DSSCs from 5.27% to 5.83% compared to that of a single TPA3T3A sensitizer due to the increasing JSC and VOC. This enhancement might be due to improved light absorption and decreasing recombination by the co-sensitizers, TPA3T1A and TPA3T2A, occupying all the empty plases on the TPA3T3A-adsorbed TiO2 surface.
Three sensitizers with triphenylamine as an electron donor, thiophene as a bridge and various numbers of acceptors/anchors cyanoacetic acid (TPA3T1A, TPA3T2A and TPA3T3A) are synthesized and TPA3T1A, TPA3T2A were used as co-adsorbents with TPA3T3A. The results show that, with co-adsorption ratio on TiO2 surface with TPA3T3A 73%, TPA3T1A 17% and TPA3T2A 10%, the photovoltaic performance of DSSCs increased from 5.27% to 5.83% compared with a single TPA3T3A sensitizer due to the increasing both of JSC and VOC. This enhancement may attribute to improved light absorption, diffusion length, and decreased recombination by fulfilling all of empty place on TPA3T3A-adsorbed TiO2. Display omitted
•TPA dyes with different number of anchors were studied for co-sensitized solar cells.•The high efficiency achieved with a ratio of 1:1:5 (TPA3T3A: TPA3T1A: TPA3T2A).•Charge recombination suppressed and e− lifetime prolonged with this cosensitizer.•Light harvesting and diffusion length also improved with this cosensitizer.
Autotransporter proteins are widely present in Gram-negative bacteria. They play a pivotal role in processes related to bacterial pathogenesis, including adhesion, invasion, colonization, biofilm ...formation, and cellular toxicity. Bioinformatics analysis revealed that
, the causative agent of scrub typhus, encodes six different autotransporter genes (
-
). Although four of these genes (
,
,
, and
) are present in diverse strains,
and
have been detected in only a limited number of strains. Previous studies have demonstrated that ScaA and ScaC are involved in the adherence of host cells. However, the putative function of other
Sca proteins has not been studied yet. In this study, we show that
is transcribed and expressed on the surface of
Boryong strain. Using a heterologous
expression system, we demonstrated that ScaB-expressing
can successfully mediate adherence to and invasion into non-phagocytic cells, including epithelial and endothelial cells. In addition, pretreatment with a recombinant ScaB polypeptide inhibits the entry of
into cultured mammalian cells. Finally, we also identified the
gene in the Kuroki and TA686 strains and observed high levels of sequence variation in the passenger domains. Here, we propose that the ScaB protein of
can mediate both adhesion to and invasion into host cells in the absence of other
genes and may play important roles in bacterial pathogenesis.
Medicago truncatula seeds were cultured and developed in Thua Thien Hue province, Vietnam, and they were used as materials for cloning a DHDPS gene with the encoding of the isozyme ...dihydrodipicolinate synthase (DHDPS) as well as optimizing the culture conditions for having the highest DHDPS gene expression in Escherichia coli BL21 StarTM (DE3) cells. The results revealed that the coding region of the DHDPS gene from M. truncatula was 100% similar with M. truncatula 4-hydroxy-tetrahydrodipicolinate synthase 2 (DHDPS2) submitted in NCBI (accession number: XM_013589555.2), coding for a long polypeptide of 307 amino acid with the molecular mass of about 33495 Da (Protein ID: XP_013445009.1). The DHDPS gene was successfully expressed in the Escherichia coli BL21 StarTM (DE3) cells with a pET200 / D-TOPO vector, and this produced the DHDPS2 protein with molecular masses of approximately 33.87 kDa (»33.5 kDa of DHDPS2 and 3.7 kDa of fusion fragment of pET 200/D-TOPO vector). The effects of the six different culture mediums of LB, SOB, SOC, YJ, HSG and TB, the induction times of 2h, 4h, 6h, 8h, 10h and 12h, and the inducer concentrations of 0.2 mM; 0.5 mM; 0.7 mM; 1.0 mM; 1.2 mM and 1.5 mM IPTG (Isopropyl â-D-1-thiogalactopyranoside) were also investigated for the purpose of optimising the expression of DHDPS2 in E. coli cells, and it was found that strong expression of recombinant DHDPS2 protein in E. coli. BL21 (DE3) cells occurred on the TB, HSG and YJ culture mediums after 8 hours with 0.2 mM inducible IPTG (BioRad).
Arbovirus infections are a serious concern in tropical countries due to their high levels of transmission and morbidity. With the outbreaks of chikungunya (CHIKV) in surrounding regions in recent ...years and the fact that the environment in Vietnam is suitable for the vectors of CHIKV, the possibility of transmission of CHIKV in Vietnam is of great interest. However, information about CHIKV activity in Vietnam remains limited.
In order to address this question, we performed a systematic review of CHIKV in Vietnam and a CHIKV seroprevalence survey. The seroprevalence survey tested for CHIKV IgG in population serum samples from individuals of all ages in 2015 from four locations in Vietnam.
The four locations were An Giang province (n = 137), Ho Chi Minh City (n = 136), Dak Lak province (n = 137), and Hue City (n = 136). The findings give us evidence of some CHIKV activity: 73/546 of overall samples were seropositive (13.4%). The age-adjusted seroprevalences were 12.30% (6.58-18.02), 13.42% (7.16-19.68), 7.97% (3.56-12.38), and 3.72% (1.75-5.69) in An Giang province, Ho Chi Minh City, Dak Lak province, and Hue City respectively. However, the age-stratified seroprevalence suggests that the last transmission ended around 30 years ago, consistent with results from the systematic review. We see no evidence for on-going transmission in three of the locations, though with some evidence of recent exposure in Dak Lak, most likely due to transmission in neighbouring countries. Before the 1980s, when transmission was occurring, we estimate on average 2-4% of the population were infected each year in HCMC and An Giang and Hue (though transmision ended earlier in Hue). We estimate lower transmission in Dak Lak, with around 1% of the population infected each year.
In conclusion, we find evidence of past CHIKV transmission in central and southern Vietnam, but no evidence of recent sustained transmission. When transmission of CHIKV did occur, it appeared to be widespread and affect a geographically diverse population. The estimated susceptibility of the population to chikungunya is continually increasing, therefore the possibility of future CHIKV transmission in Vietnam remains.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Recent developments in addressing dental aesthetic concerns, encompassing issues like teeth discoloration and halitosis, underscore the demand for safer alternative solutions.
This study aims to ...confirm the effects of lactic acid bacteria (LAB) from kimchi on artificial teeth bleaching and their potential impact in terms of preventing halitosis-related bacteria.
To evaluate the antimicrobial effects against oral pathogens, disc diffusion tests and broth microdilution methods were used. Additionally, crystal violet analysis was performed to confirm the biofilm inhibition effect. The bleaching effects on stained artificial teeth were analyzed using the CIEDE2000 colorimetric method. Statistical analyses were performed using GraphPad Prism 9 with one-way and two-way ANOVA, with the significance level set at α < 0.05.
The strain THK-30, isolated from kimchi, exhibited antibacterial activity against
,
, and
, and was identified as
. Moreover, THK-30 showed a synergistic antibacterial effect against Gram-negative oral pathogens with 8% sodium hexametaphosphate (SHMP). In the stained artificial teeth bleaching test and artificial teeth biofilm inhibition test, the cell-free supernatant of THK-30 displayed significant teeth bleaching effects and caused the inhibition of biofilm formation, both independently and in combination with SHMP 8%.
This study has demonstrated the potential applicability of LAB in teeth discoloration and halitosis. These findings are poised to provide a foundation for the development of research pertaining to the control of oral bacteria.
A biohybrid material based on poly(lactic acid)(PLA) incorporated with low contents of polyethylene glycol (PEG) functionalized graphene oxide (GO) was prepared via melting process and their ...structure, morphology, mechanical performance, and thermal properties were studied in detail. SEM and TEM characterizations confirmed that the functionalization of GO with PEG (PEGmGO) promoted its exfoliation into thin exfoliated nanosheets, thereby improving the interactions between PEGmGO filler and PLA matrix at interface. FT-IR spectra showed the presence of strong polar and hydrogen bonding interactions between components in the biohybrid. Mechanical and thermal tests indicated that there was the significant improvement of the stiffness, strength, and thermal stability of such biohybrid material with the addition of 0.3 phr PEGmGO, as compared to pure PLA, PEG-plasticized PLA, PEG-plasticized PLA/GO, and other surveyed PEG-plasticized PLA/PEGmGO biohybrids. This behavior was attributed to the homogeneous dispersion of the PEGmGO nanofillers within PLA matrix along with their strong interfacial interaction. The as-obtained biohybrids show highly potential to be useful in the bioengineering applications.
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