The work aims to study the removal of crystal violet (CV) using laterite soil with surface modification by surfactant (SML). Surface modification of laterite soil was conducted by pre-adsorption of ...sodium dodecyl sulfate (SDS) at pH 4 and low ionic strength to enhance removal of CV. The effective conditions for CV removal through adsorption technique using SML were optimized and found to be contact time 60 min, pH 6, adsorbent dosage 5 mg/mL, and 5 mM NaCl as background electrolyte. The highest removal of CV using SML reached to 86.5% under optimum conditions. We used Fourier transform infrared spectroscopy (FT-IR) to evaluate the change of surface vibrational groups of laterite after SDS pre-adsorption and after CV adsorption while the different charged surface was determined by ζ potential measurements. The CV adsorption onto SML increased when increasing ionic strength from 1 to 10 mM. Nevertheless, at high ionic strength, this trend is reversal due to desorption of SDS from laterite surfaces. Adsorption isotherms of CV onto SML at different NaCl concentrations were tried to fit by Langmuir, Freundlich, and a two-step adsorption models. The adsorption kinetics were in good agreement with pseudo-second-order model. The removal efficiency of CV after four regenerations still reached higher than 85%. On the basis of adsorption isotherms, charged surface change by ζ potential and surface modification by FT-IR, we suggest that CV adsorption onto SML was induced by both non-electrostatic and electrostatic interactions. We also demonstrate that SML is a novel, reusable, and low-cost adsorbent for cationic dye removal from aqueous solution.
In HIV type 1 (HIV-1) infection, virus-specific B-cell and neutralizing antibody (NAb) responses are impaired but exert selective pressure on target viral Envelope (Env) resulting in prominent ...sequence diversification among geographical areas. The basal induction patterns of HIV Env-specific B cells and their interaction with HIV Env awaits clarification.
We investigated the relationship of Env polymorphisms and Env-specific B-cell responses in treatment-naive HIV-1 CRF01_AE-infected Vietnamese.
Samples of 43 HIV-1 CRF01_AE infection-identified individuals were divided into acute-phase ( n = 12) and chronic-phase ( n = 31) by combined criteria of serological recent-infection assay and clinical parameters. We quantified subcloning-based polymorphic residue site numbers in plasma-derived Env variable region 1-5 (V1-V5)-coding regions within each individual, designating their summation within each region as variant index. Peripheral blood Env gp 140-specific B-cell responses and plasma neutralizing activity of Env pseudoviruses were examined to analyze their relationship with variant index.
HIV-1 CRF01_AE Env gp140-specific total B-cell and plasma cell (CD19 + IgD - CD27 + CD38 + CD138 + ) responses were determined. In chronic-phase samples, significant correlation of variant index in all Env V1-V5 regions with Env-specific plasma cell responses was shown, and V1-V5 total variant index correlated stronger with Env-specific plasma cell as compared with total Env-specific B-cell responses. Env V5 variant index was significantly higher in chronic-phase cross-neutralizers of V5-polymorphic/VRC01-insensitive CRF01_AE Env.
Results revealed the association between circulating Env-specific plasma cell responses and Env polymorphisms, implicating selective pressure on Env by plasma cell-derived antibodies and conversely suggests that Env-specific B-cell induction alone is insufficient for exerting Env selective pressure in HIV infection.
Acute‐phase neutralizing antibody (NAb) passive immunization in simian immunodeficiency virus (SIV)‐infected rhesus macaques (Macaca mulatta) can confer stringent viremia control with T‐cell ...augmentation. In one NAb‐infused SIV partial controller, we identify chronic‐phase Nef‐specific CD107a+ CD4+ T‐cell response maintenance, implicating that NAb infusion modulates long‐term T‐cell responses even within viremic control.
Food and beverage poisoning is detrimental to people's health since it can lead to fever, stomachaches, and even death. To rapidly detect the presence of foodborne pathogens, conventional PCR assays ...are currently widely employed. Meanwhile, isothermal PCR methods, in which the amplification reactions take place at a low and constant temperature, have lately emerged as effective and alternative means for quickly identifying pathogens in low-resource settings.
Staphylococcus aureus
and
Pseudomonas aeruginosa
are two of the most concerning foodborne bacterial infections. In this work, an isothermal PCR assay based on the Recombinase Polymerase Amplification (RPA) method was developed to simultaneously detect
S. aureus
and
P. aeruginosa
with high sensitivity and specificity. The limit of detection for multiplex RPA was 10 and 30 fg/reaction of
S. aureus
and
P. aeruginosa
genomic DNA, respectively. Furthermore, the reaction time was reduced to only 25 minutes, with a low incubation temperature of 39°C. Multiplex RPA reactions, in particular, were successful in directly identifying as low as 1 and 5 CFU/reaction of
S. aureus
and
P. aeruginosa
cells, respectively, without the need for DNA genome extraction. Moreover, the multiplex RPA reliably detected the two foodborne bacteria in milk, fruit juice, and bottled water samples. In conclusion, the direct multiplex RPA reported in this work offers a quick, easy, sensitive, and effective alternative approach for detecting the presence of
S. aureus
and
P. aeruginosa
without the requirement of a pricey instrument or highly-trained personnel.
In human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections, host major histocompatibility complex class I (MHC-I) genotypes have a great impact on viral replication and ...MHC-I-associated viral genome mutations are selected under CD8+ T-cell pressure. Association of MHC-I genotypes with HIV/SIV control has been investigated at MHC-I allele levels but not fully at haplotype levels. We previously established groups of rhesus macaques sharing individual MHC-I haplotypes. In the present study, we compared viral genome diversification after SIV infection in macaques possessing a protective MHC-I haplotype, 90-010-Id, with those possessing a non-protective MHC-I haplotype, 90-010-Ie. These two MHC-I haplotypes are associated with immunodominant CD8+ T-cell responses targeting similar regions of viral Nef antigen. Analyses of viral genome sequences and antigen-specific T-cell responses showed four and two candidates of viral CD8+ T-cell targets associated with 90-010-Id and 90-010-Ie, respectively, in addition to the Nef targets. In these CD8+ T-cell target regions, higher numbers of mutations were detected at the setpoint after SIV infection in macaques possessing 90-010-Id than those possessing 90-010-Ie. These results indicate higher selective pressure on overall CD8+ T-cell targets associated with the protective MHC-I haplotype, suggesting a pattern of HIV/SIV control by multiple target-specific CD8+ T-cell responses.
•Impact of MHC-I haplotypes on HIV/SIV replication was not fully examined.•We examined SIV mutations associated with a protective MHC-I haplotype.•Higher overall protective MHC-I haplotype-associated selective pressure was shown.•Study contributes to understanding of a CD8+ T cell-based HIV control mechanism.
SARS-CoV-2 infection presents clinical manifestations ranging from asymptomatic to fatal respiratory failure. Despite the induction of functional SARS-CoV-2-specific CD8
+
T-cell responses in ...convalescent individuals, the role of virus-specific CD8
+
T-cell responses in the control of SARS-CoV-2 replication remains unknown. In the present study, we show that subacute SARS-CoV-2 replication can be controlled in the absence of CD8
+
T cells in cynomolgus macaques. Eight macaques were intranasally inoculated with 10
5
or 10
6
TCID
50
of SARS-CoV-2, and three of the eight macaques were treated with a monoclonal anti-CD8 antibody on days 5 and 7 post-infection. In these three macaques, CD8
+
T cells were undetectable on day 7 and thereafter, while virus-specific CD8
+
T-cell responses were induced in the remaining five untreated animals. Viral RNA was detected in nasopharyngeal swabs for 10–17 days post-infection in all macaques, and the kinetics of viral RNA levels in pharyngeal swabs and plasma neutralizing antibody titers were comparable between the anti-CD8 antibody treated and untreated animals. SARS-CoV-2 RNA was detected in the pharyngeal mucosa and/or retropharyngeal lymph node obtained at necropsy on day 21 in two of the untreated group but undetectable in all macaques treated with anti-CD8 antibody. CD8
+
T-cell responses may contribute to viral control in SARS-CoV-2 infection, but our results indicate possible containment of subacute viral replication in the absence of CD8
+
T cells, implying that CD8
+
T-cell dysfunction may not solely lead to viral control failure.
Despite their classification as low pathogenicity avian influenza viruses (LPAIV), A/H9N2 viruses cause significant losses in poultry in many countries throughout Asia, the Middle East and North ...Africa. To date, poultry surveillance in Vietnam has focused on detection of influenza H5 viruses, and there is limited understanding of influenza H9 epidemiology and transmission dynamics. We determined prevalence and diversity of influenza A viruses in chickens from live bird markets (LBM) of 7 northern Vietnamese provinces, using pooled oropharyngeal swabs collected from October to December 2014. Screening by real time RT-PCR revealed 1207/4900 (24.6%) of pooled swabs to be influenza A virus positive; overall prevalence estimates after accounting for pooling (5 swabs/pools) were 5.8% (CI 5.4–6.0). Subtyping was performed on 468 pooled swabs with M gene Ct<26. No influenza H7 was detected; 422 (90.1%) were H9 positive; and 22 (4.7%) were H5 positive. There was no evidence was of interaction between H9 and H5 virus detection rates. We sequenced 17 whole genomes of A/H9N2, 2 of A/H5N6, and 11 partial genomes. All H9N2 viruses had internal genes that clustered with genotype 57 and were closely related to Chinese human isolates of A/H7N9 and A/H10N8. Using a nucleotide divergence cutoff of 98%, we identified 9 distinct H9 genotypes. Phylogenetic analysis suggested multiple introductions of H9 viruses to northern Vietnam rather than in-situ transmission. Further investigations of H9 prevalence and diversity in other regions of Vietnam are warranted to assess H9 endemicity elsewhere in the country.
•We report detection of highly pathogenic avian influenza (HPAI) from healthy chickens in Live Bird Markets of Vietnam. Because all breeds of domestic chickens are extremely susceptible to HPAI, we speculate that HPAI detections from market chickens may reflect infections that occur after arrival in the market. Alternatively, shedding of HPAI from healthy birds may reflect vaccine-induced protective immunity that mitigates disease but does not block viral infection.•As many as 49% of all pooled surveillance swabs were positive for influenza A virus, corresponding to an overall Influenza A prevalence of 5.45% (95% Confidence Interval 5.4-6.0%).•Low pathogenicity avian influenza (LPAI) H9N2 accounted for the vast majority of all influenza A detections in market chickens sampled from 9 northern provinces.•To date there is no evidence to suggest an interaction effect between circulation of H5 and H9 viruses; however sampling strategies that involve pooling of surveillance swabs from multiple birds greatly complicates the assessment of co-infection rates or evaluation of epidemiological associations.
An estimated 73% of emerging infections are zoonotic in origin, with animal contact and encroachment on their habitats increasing the risk of spill-over events. In Vietnam, close exposure to a wide ...range of animals and animal products can lead to acquisition of zoonotic pathogens, a number of which cause central nervous system (CNS) infections. However, studies show the aetiology of CNS infections remains unknown in around half of cases. We used samples and data from hospitalised patients with CNS infections, enrolled into the Vietnam Initiative on Zoonotic Infections multicentre study, to determine the association between aetiology and animal contact including those in whom the cause was unknown. Among 933 patients, a pathogen or an antibody response to it was identified in 291 (31.2%, 95% CI 28.3–34.3%). The most common pathogens were
Streptococcus suis
(
n
= 91 (9.8%, 8.0–11.9%)) and Japanese encephalitis virus (JEV) (
n
= 72 (7.7%, 6.1–9.7%)). Commonly reported animal contact included keeping, raising or handling (
n
= 364 (39.0%, 35.9–42.2%)) and handling, cooking or consuming raw meat, blood or viscera in the 2 weeks prior to symptom onset (
n
= 371 (39.8%, 36.6–43.0%)), with the latter most commonly from pigs (
n
= 343 (36.9%, 33.8–40.1%). There was no association between an unknown aetiology and exposure to animals in a multivariate logistic regression. Further testing for unknown or undetected pathogens may increase diagnostic yield, however, given the high proportion of zoonotic pathogens and the presence of risk factors, increasing public awareness about zoonoses and preventive measures can be considered.
This work focuses on the formation of Ir3+ dopants in the host TiO2 matrix to decrease the band gap energy and a built-in electric field at the interface between Ir0 and TiO2. X-ray diffraction ...results show that the anatase percentage is increased from 70 to 90% with increasing Ir doping concentration using the hydrothermal procedures at 200 °C for 24 h. X-ray photoelectron spectroscopy results demonstrate that the binding energies of Ti4+ (Ti 2p1/2 and Ti 2p3/2) shift slightly positively after Ir doping. The influence of Ir doping on the photoelectrochemical and optical properties of anatase/rutile TiO2 is characterized by linear sweep voltammetry and photoluminescence spectroscopy. These results suggest that the photoinduced electron–hole pair recombination rate is decreased in the presence of the Ir dopant. Outstanding H2 evolution reaction efficiencies of 48 and 23.5 μmol·h–1·g–1 with apparent quantum efficiency values of approximately 15.7 and 4.5% determined at 365 and 420 nm, respectively, are achieved with the 1.0% Ir/TiO2 specimen in photocatalytic systems to enhance hydrogen evolution.
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