Inhibition Test Research Articles

Facilitating Intracellular Electron Bifurcation by Mediating Flavin-Based Extracellular and Transmembrane Electron Transfer: A Novel Role of Pyrogenic Carbon in Dark Fermentation for Hydrogen Production.

Pyrogenic carbon is considered an enhancer to H2-yielding dark fermentation (DF), but little is known about how it regulates extracellular electron transfer (EET) and influences transmembrane respiratory chains and intracellular metabolisms. This study addressed these knowledge gaps and demonstrated that wood waste pyrogenic carbon (biochar) could significantly improve the DF performance; e.g., addition of pyrogenic carbon produced by pyrolysis at 800 °C (PC800) increased H2 yield by 369.7%. Biochemical quantification, electrochemical analysis, and electron respiratory chain inhibition tests revealed that PC800 promoted the extracellular flavin-based electron transfer process and further activated the acceleration of the transmembrane electron transfer. Comparative metagenome/metatranscriptome analyses indicated that the flavin-containing Rnf complex was the potential transmembrane respiratory enzyme associated with PC800-mediated EET. Based on NADH/NAD+ circulation, the promoted Rnf complex could stimulate the functions of the electron bifurcating Etf/Bcd complex and startup of glycolysis. The promoted Etf/Bcd could further contribute to balance the NADH/NAD+ level for glycolytic reactions and meanwhile provide reduced ferredoxin for group A1 [FeFe]-hydrogenases. This proton-energy-linked mechanism could achieve coupling production of ATP and H2. This study verified the important roles of pyrogenic carbon in mediating EET and transmembrane/intracellular pathways and revealed the crucial roles of electron bifurcation in DF for hydrogen production.

Биотестирование меламина с использованием многокомпонентной тест-системы

In recent decades, halogen-containing flame retardants have been gradually replaced by safer flame retardants, including nitrogen-containing compounds. However, their ecotoxicity is poorly studied. The ecotoxicity of melamine, a widely used nitrogen flame retardant, at concentrations equal to MPC in water (4 mg/L), 5 MPC (20 mg/L) and 10 MPC (40 mg/L) was assessed in this study using a complex of test organisms. The assessment of ecotoxicity using the dehydrogenase activity of Dietzia maris AM3 as a test microorganism revealed a stimulating effect of melamine at a concentration equivalent to the MPC; concentrations of 5 and 10 MPC inhibited the activity of dehydrogenases by 19.3% and 10.5%, respectively, indicating low toxicity. No toxic effects were observed on protococcal algae Chlorella vulgaris Beijer at any of the tested concentrations. The effect of melamine solutions on the mortality of crustaceans Daphnia magna Straus was noted only at a concentration of 10 MPC, and the mortality rate was 25%. Lemna growth inhibition test showed that melamine at concentrations equal to the MPC and 5 MPC had an inhibitory effect on the growth of Lemna minor L. It also caused a significant decrease (by 47–52%) in the total chlorophyll content in fronds when exposed to all studied concentrations of melamine.

Evaluation of citronella oil nanoemulsion formulation against the insect-stored pest Callosobruchus maculatus (Fab.) (Coleoptera: Bruchidae)

Citronella (Cymbopogon nardus) produces essential oil and has the potential to be developed as a botanical insecticide. However, in its development, botanical insecticides encountered several obstacles. Utilizing nanotechnology in nanoemulsion preparations is one method to overcome these challenges. This research aimed to determine the contents of the citronella oil nanoemulsion (CiONano) and citronella oil non-nano emulsion (CiONonNano) formulations and evaluate the toxicity, repellency, and prevention of oviposition against female adults of Callosobruchus maculatus. This was the first work to evaluate the nanoemulsion of citronella oil prepared from spontaneous emulsification against C. maculatus. Chemical content testing used the GCMS method. A toxicity test using the contact method (LC50), used a probit program, while testing for repellency and oviposition deterrence was carried out using the no-choice method. The highest chemical component of CiONonNano and CiONano was citronella (37.56 and 38.97%, respectively), followed by citronellol (17.71 and 18.99%, consecutively) and geraniol (14.78 and 15.38%, respectively). In general, the CiONano formulation showed higher repellency and toxicity than CiONonNano. The LC50 values of CiONano were 10.03%. These values were 4.49 times lower than the LC50 of CiONonNano. However, the results of the oviposition inhibition test showed different results, the CiONonNano formulation had a higher oviposition inhibition capacity for adult female C. maculatus than CiONano. As a result, it is necessary to optimize the CiONano formulation to obtain consistent results in controlling C. maculatus.

Anti-Coronavirus Activity of Chitosan-Stabilized Liposomal Nanocarriers Loaded with Natural Extracts from Bulgarian Flora.

Disease's severity, mortality rates, and common failures to achieve clinical improvement during the unprecedented COVID-19 pandemic exposed the emergency need for new antiviral therapeutics with higher efficacy and fewer adverse effects. This study explores the potential to encapsulate multi-component plant extracts in liposomes as optimized delivery systems and to verify if they exert inhibitory effects against human seasonal betacoronavirus OC43 (HCoV-OC43) in vitro. The selection of Sambucus nigra, Potentilla reptans, Allium sativum, Aesculus hippocastanum, and Glycyrrhiza glabra L. plant extracts was based on their established pharmacological and antiviral properties. The physicochemical characterization of extract-loaded liposomes was conducted by DLS and electrokinetics. Encapsulated amounts of the extract were evaluated based on the total flavonoid content (TFC) and total polyphenol content (TPC) by colorimetric methods. The BALB 3T3 neutral red uptake (NRU) phototoxicity/cytotoxicity assay was used to estimate compounds' safety. Photo irritation factors (PIFs) of the liposomes containing extracts were <2 which assigned them as non-phototoxic substances. The antiviral capacities of liposomes containing medicinal plant extracts against HCoV-OC43 were measured by the cytopathic effect inhibition test in susceptible HCT-8 cells. The antiviral activity increased by several times compared to "naked" extracts' activity reported previously. A. hippocastanum extract showed 16 times higher inhibitory properties reaching a selectivity index (SI) of 58.96. Virucidal and virus-adsorption effects were investigated using the endpoint dilution method and ∆lgs comparison with infected and untreated controls. The results confirmed that nanoparticles do not directly affect the viral surface or cell membrane, but only serve as carriers of the active substances and the observed protection is due solely to the intracellular action of the extracts.

DCC in the cerebral cortex is required for cognitive functions in mouse.

Schizophrenia (SZ) is a highly heritable mental disorder, and genome-wide association studies have identified the association between deleted in colorectal cancer (DCC) and SZ. Previous study has shown a lowered expression of DCC in the cerebral cortex of SZ patient. In this study, we identified novel single nucleotide polymorphisms (SNPs) of DCC statistically correlated with SZ. Based on these, we generated DCC conditional knockout (CKO) mice and explored behavioral phenotypes in these mice. We observed that deletion of DCC in cortical layer VI but not layer V led to deficits in fear and spatial memory, as well as defective sensorimotor gating revealed by the prepulse inhibition test (PPI). Critically, the defective sensorimotor gating could be restored by olanzapine, an antipsychotic drug. Furthermore, we found that the levels of p-AKT and p-GSK3α/β were decreased, which was responsible for impaired PPI in the DCC-deficient mice. Finally, the DCC-deficient mice also displayed reduced spine density of pyramidal neurons and disturbed delta-oscillations. Our data, for the first time, identified and explored downstream substrates and signaling pathway of DCC which supports the hypothesis that DCC is a SZ-related risky gene and when defective, may promote SZ-like pathogenesis and behavioral phenotypes in mice.

Use of “ARRIAH-AviFluVac” vaccine in turkeys, geese and ducks

“ARRIAH-AviFluVac” vaccine against H5 avian influenza was demonstrated to be effective for ducks, geese and turkeys both in the laboratory and production environment. When administered to ducks at 0.5; 1.0 and 1.5 cm3, the vaccine provided 100%-effective protection of birds against the disease and death after challenge with the relevant high pathogenicity avian influenza virus of subtype H5N1, clade 2.3.4.4b. Singular 0.5–1.5 cm3 inoculation induced formation of antibodies, which were detected in the hemagglutination inhibition test at the titres that ranged from 4.3 to 6.1 log2. The vaccine facilitated 9–26-fold decrease in the virulent virus shedding by the ducks. Protection of turkeys vaccinated at the dose of 1.0 cm3 was maintained at the level of 87.5% after challenge with high pathogenicity avian influenza virus of subtype H5N1, clade 2.3.4.4b. The vaccine induced formation of antibodies at the titres of 4.9 and 5.5 log2 in turkeys after singular and double vaccination at the dose of 1.0 cm3, respectively. It was demonstrated, that after double administration of 1.0 cm3 of “ARRIAH-AviFluVac” vaccine, the post-vaccinal avian influenza antibody level exceeded 5.0 log2 in 75.9–90.0% of the geese population. The most appropriate way of the vaccine use in turkeys, ducks and geese involves at least its double administration at the double commercial dose. Higher species resistance of ducks to the challenge with avian influenza virus of subtype H5, clade 2.3.4.4bas compared to turkeys was also demonstrated.

Time dependent anti-corrosion and anti-scaling efficiency of polyepoxysuccinic acid inhibitor in simulated hard water

In this study, the time-dependent performance of a phosphorus-free corrosion and scale inhibitor primarily composed of polyoxyuccinic acid (PESA) and zinc salts was investigated in a laboratory-simulated hard water environment. Long-term static scale inhibition tests and corrosion rotation coupon tests were conducted under two temperature conditions, 45 °C and 80 °C, following established literature standards. Changes in water quality, scale morphology, metal corrosion status, and electrochemical impedance were monitored using calcium ion concentration analysis, optical microscopy imaging, X-ray diffraction (XRD), and electrochemical testing. The study revealed a progressive decline in the corrosion and scale inhibition efficiency of the phosphorus-free inhibitor in simulated hard water with calcium carbonate hardness levels of 300, 400, and 500 mg/L over time. Moreover, higher water hardness accelerated corrosion onset, suggesting that calcium carbonate deposition promotes metal corrosion under the experimental conditions. Density functional theory (DFT) calculations indicated that PESA chemically adsorbs onto both metal and calcite surfaces, underscoring its dual role in corrosion and scale inhibition. These findings underscore the intrinsic corrosion and scale inhibition capabilities of PESA, complementing its synergistic film-forming properties with Zn2+.

INHIBITORY EFFECT OF BASE GEDE ETHANOL EXTRACT AGAINTS BACTERIAL GROWTH OF Escherichia coli

Foodborne disease is a condition in which food is contaminated by microorganisms or chemicals, causing disease. One of the microorganisms that most often causes this condition is Escherichia coli. There is an assumption which states that, base gede/base genep has antibacterial properties which inhibit the growth of bacteria in typical Balinese food such as lawar. Various studies have proven that the basic ingredients of base gede have antibacterial activity obtained from secondary metabolites. The purpose of this study was to determine the phytochemical compounds contained in the base gede and the inhibitory power of the base gede in inhibiting the growth of the Escherichia coli ATCC 25922. This study examined the content of secondary metabolites qualitatively and the experimental test was the true experimental posttest only control group design. The method used was the disk diffusion (Kirby Bauer) with variations in the concentration of ethanol extract base gede as many as four groups (25%, 50%, 75% and 100%) and the negative control group was 96% ethanol and the positive control group ciprofloxacin 5g. The results of the phytochemical test found that the base gede ethanol extract contained phenols, saponins, tannins, alkaloids, terpenoids, and flavonoids. Inhibition test results observed inhibition zones formed at concentrations of 50%, 75%, 100% and K+ with diameters respectively 5.65+/-0.65 mm ; 7.00+/-1.35mm ; 7.78+/-1.18 mm dan 34.52+/-1.49 mm. Kruskal wallis test showed a value of p = 0.001 (p &lt;0.05) which showed that the concentration group had an effect on the inhibition of E.coli ATCC 25922. There was a significant difference between the 50% and 100% concentrations obtained from the Mann-Whitney analysis with value of p = 0.043 (p&lt;0.05). Keywords : Inhibition test, base gede, Escherichia coli

Duckweed-based optical biosensor for herbicide toxicity assessment

In response to the pervasive issue of herbicide pollution in environmental water bodies, particularly from herbicides used extensively in agriculture, traditional chemical-based water quality analysis methods have proven costly and time-consuming, often failing to meet regulatory standards. To overcome these limitations, global environmental agencies have turned to rapidly-growing species like duckweed as bioindicators for herbicide and pesticide contamination. However, conventional biological assessment methods, such as the 168-h duckweed growth inhibition test, are slow and lack real-time monitoring capabilities. To address this challenge, we developed an innovative approach by integrating opto-mechanical technology with duckweed to create a cost-effective biosensor for herbicide detection, priced under $10 USD per system. This advancement allows for the rapid detection of herbicide impacts on duckweed growth within just 48 h, significantly improving upon traditional methods. Our biosensor achieves detection limits of 10 ppm (p < 0.05) for glyphosate and 1 ppm (p < 0.05) for glufosinate, both prominent herbicides globally. This mini-biosensing platform offers a practical alternative to the official method, which requires 168 h and higher thresholds (36.4 ppm for glyphosate and 34.0 ppm for glufosinate) for routine environmental analysis. Thus, these duckweed-based optical biosensors represent a promising advancement in environmental monitoring, enhancing accessibility and efficacy for widespread adoption globally.

Systematization of a toxicity screening method based on a combination of chemical analysis and the delayed fluorescence algal growth inhibition test for use in emergency environmental surveys.

In recent years, heavy rainfall disasters linked to climate change have become more frequent, raising concerns about the release of chemicals stored in factories. Assessing chemical contamination during such emergencies therefore necessitates the development of a quick and easy method for evaluating hazardous contaminants in combination with toxicity testing. This study proposes a "toxicity screening" method that combines biological response testing and chemical analysis to systematically evaluate hazardous contaminants in emergency situations. The toxicity screening method evaluates the water quality in three steps, including water quality measurements and a delayed fluorescence (DF) assay, metal content measurements and a DF assay, and targeted screening analysis and a DF assay. The efficacy of this method was tested using industrial wastewater from 14 locations. Seven of the samples were non-toxic, while the other seven samples were toxic, displaying no observed effect concentration (NOEC) values ranging from 0.625 to 20%. Two toxic samples in the first phase possessed high total chlorine concentrations (0.4mg L-1) and conductivities (2200 mS m-1), indicating that the main sources of toxicity were residual chlorine and a high salt concentration. In the second phase, metal content analysis identified metals as the toxicity cause in four samples. In the third phase, the organic contaminants were analyzed, and tri-n-octyl phosphate (TNOP) was detected at a concentration of 0.00027mg L-1. The results of solid-phase extraction experiments and exposure tests with TNOP alone indicated that the contribution of TNOP to the toxicity was negligible and that chemicals not adsorbed on the solid-phase extraction cartridges were the cause of toxicity. The proposed method can therefore be considered effective for disaster-related water quality assessment, delivering results within 12days.

Fraction Activities Rosella Flower (Hibiscus Sabdariffa L) as an Antibacterial and Antibiofilm Escherichia Coli ATCC 25922

Rosella flowers (Hibiscus sabdariffa L) contain alkaloid, flavonoid, saponin and tannin compounds. The compounds contained in rosella flowers have activity as antibacterial and antibiofilm. Biofilm is the ability of microorganisms that stick to the surface of objects and form a matrix. This study aims to antibacterial and biofilm activity in the form of inhibition of biofilm formation and biofilm degradation of E.coli bacteria. Rosella flowers were extracted using maceration method with 96% ethanol solvent. The thick extract was then fractionated with n-hexane, ethyl acetate and water solvents. Antibacterial activity test using diffusion and dilution methods followed by observation of cell wall and membrane damage using SEM and ion leakage with AAS. Biofilm activity test was conducted using a microplate device and readings were taken at a wavelength of 595 nm. The absorbance results of the inhibition percentage to determine the IC50 and EC50 values. The average IC50 values of biofilm formation inhibition test on extract, n-hexane fraction, ethyl acetate fraction and water fraction against E. coli bacteria are 1.059; 1.070; 0.921; 0.863. The EC50 values of biofilm degradation test on extract, n-hexane fraction, ethyl The minimum killing concentration value of rosella flower water fraction against E. coli is 25 mg/ml. the effect of the active fraction of rosella flower on E. coli bacteria is on the cell wall and cell membrane

EFFECT OF MORINGA (Moringa oleifera) LEAF EXTRACT ON IN VITRO INHIBITION OF Candida albicans BIOFILM

Background: Oral candidiasis is an opportunistic infection in the oral cavity. This infection is caused by the fungus Candida albicans. The most important virulent attribute of this fungus is its ability to form biofilms, which can adhere to mucosa, epithelial lining, organs, prostheses or dentures. The formed biofilm is resistant to antifungal drugs. Objectives: The purpose of this study was to determine the effect of Moringa (Moringa oleifera) leaf extract on the inhibition of Candida albicans biofilm formation in vitro. Methods: This type of research is experimental study using post tests with control group design. Fungus used in this study was Candida albicans ATCC 10231. Determination of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were conducted by microdilution method. Inhibition test of C. albicans biofilm formation was carried out using the polystyrene microplate assay method. Concentration of extracts used in this study were 12.5%, 6.25%, 3.13% and 1.57%. Inhibitory activity of biofilm was measured using a crystal violet (CV) assay. Results: The results showed that MIC of Moringa leaf extract against the fungus C. albicans was at a concentration of 6.25%. Moringa leaf extract starting at a concentration of 3.13% already has had ability to inhibit formation of C. albicans biofilm. Conclusion: It can be concluded that Moringa leaf extract can inhibit formation of Candida albicans biofilm, so it can be developed as an alternative herbal ingredient to prevent oral candidiasis.EFFECT OF MORINGA (Moringa oleifera) LEAF EXTRACT ON IN VITRO INHIBITION OF Candida albicans BIOFILM

Structural, morphological, optical, and antimicrobial study of Mikania micrantha (leaf) extract treated zinc doped cobalt ferrite nanoparticles and antibacterial clothing applications

To manage pathogenic diseases, different applications of nanotechnology have been harnessed to improve the antimicrobial and self-cleaning attributes of materials. The objective of this study is to examine the anti-microbial activity of silk thread; coated (ultra-sonication method) with Zn doped cobalt ferrite nanoparticles with future prospects of developing interlayer of surgical facemask or producing antibacterial wearing. The nanoparticles were synthesized following the co-precipitation method by using Mikania micrantha leaf extract. The potential antibacterial activity (against E. coli and S. aureus) of the thread as well as the nanoparticles was recorded using the Zone of Inhibition (ZOI) test result. XRD results showed the cubic crystal structure and the lattice parameter change due to Zn doping. SEM findings revealed particle agglomeration, though the particles retained an approximately spherical shape of around 52.498 nm for undoped and 32.13 nm for doped materials. FT-IR analysis confirmed that flavonoids from the leaf extract stabilized the nanoparticles. This research investigated the antibacterial capabilities of threads coated with nanoparticles; using the agar well diffusion method, the study established the robust antibacterial capabilities of the nanoparticles-coated thread. Notably, the CoFe2O4 NPs exhibited strong antimicrobial activity against specific bacterial strains, and Zn doping enhances this characteristic.

Executive functions in male and female older adults with aligned levels of VO2max.

Studies have shown a positive relationship between cardiorespiratory fitness (CRF) and executive functioning in older adults. Although this relationship has been well established, there seems to be a gap in the literature on the role of sex differences concerning CRF and executive functions. The current study aimed to assess the effect of sex in the relationship between CRF and cognition in older adults by stratifying the results to examine effects in males and females. Ninety-six older adults (61 females) gave their written, informed consent to participate in this cross-sectional study. All participants underwent a maximal continuous graded exercise test on a cycle ergometer to assess their maximal oxygen uptake (VO<inf>2max</inf>) and a computerized Stroop task (naming, inhibition, and switching) to assess their executive functions. According to VO<inf>2max</inf> test results and the American College of Sports Medicine's guidelines, females and males were classified into higher-fit and lower-fit groups. A general linear model and estimated marginal means analyses were applied. Results showed no significant differences in the naming, inhibition and switching performance tests between male and female older adults (P>0.05). Based on the observed positive relationship between CRF and executive functioning, the data of the current study supports the idea that aerobic exercise, which typically increases CRF, is well-situated to improve executive functioning in older adults, irrespective of sex.

Advancing Oil Production Efficiency with Next-Generation Nano emulsion Capsules: Harnessing Doped MgZnO2 for Superior Inhibition of Calcite Scale Formation

Abstract This work presents doped MgZnO2 nano emulsion capsules as a novel approach for reducing calcite scale formation in oil production. The nano emulsion capsules are synthesized via ultrasonication and precipitation methods, with morphology and size distribution analysed by scanning electron microscopy (SEM), transmission electron microscope [TEM] and dynamic light scattering (DLS).` with an average particle size of 50 nm. Static scale inhibition tests showed over 90% inhibition efficiency at a Nano emulsion concentration of 100 mg/L. Rigorous static and dynamic scale inhibition testing precipitation and showcases remarkable efficiency exceeding 80% in preventing calcite deposition under simulated conditions. Gravimetric validates cation and online pressure monitoring validate superior performance compared to conventional inhibitors, with up to 30% enhancement in mitigation. The controlled release properties of the Nano emulsion capsule allow for persistent scale inhibition even after 72 hours of continuous operation. Furthermore, ecotoxicity evaluations through bioassays affirm the eco-friendly characteristics of the Nano emulsion technology. As a whole, this research shows how highly promising doped MgZnO2 Nano emulsion capsules are as a long-term, high-performing solution to scale-related problems in the oil sector.

Cytotoxic, antioxidant, and enzyme inhibitory activities of Centaurea stapfiana extracts and their HPLC-ESI-QTOF-MS profiles: Insights into an unexplored Centaurea species

The members of the genus Centaurea have a great interest in pharmaceutical and nutraceutical fields due to their biological potential. Based on this information, we aimed to evaluate the biological properties (antioxidant, enzyme inhibition and cytotoxicity) and chemical profile of the extract of Centaurea stapfiana, an unstudied species. The highest total phenolic content was found in the ethanol/water extract with 32.17 mg GAE/g. A total of 102 of them were identified by HPLC-ESI-QTOF-MS analysis. These compounds were mainly hydroxybenzoic acid and hydroxycinnamic acid as well as flavonoids. In the antioxidant tests, the ethanol/water extract had the best free radical scavenging and reducing ability. However, in the enzyme inhibition test, the ethanol extract was the most active. The extracts were also tested on two tumour cell lines (RAW 264.7 and HepG2) and one non-tumour cell line (S17). The ethanol extract showed the promising effect on HepG2 (cell viability: 28.6 % at 50 g/ml). Furthermore, we examined the interactions between the compounds and enzymatic and cellular targets. A good interaction was found between quercetin-3-xylosyl-(1- > 6)-glucoside and iNOS. In summary, our results suggest that C. stapfiana can be considered as a versatile raw material for the development of health-promoting applications in the pharmaceutical and cosmeceutical fields.

Evaluation of Phytochemicals, Antioxidants, and Antidiabetic Activity of Nitophyllum marginale by Using Analytical Approaches

Background: Nitophyllum marginale holds potential for medical applications due to its bioactive compounds, making it promising for developing new therapeutic interventions. Our study aims to evaluate the bioactivity of Nitophyllum marginale extracts obtained using methanol and chloroform solvents. We focus on analyzing the phytochemical profile, antioxidant activity, and antidiabetic potential of seaweed extract in this study. By examining the medicinal properties of Nitophyllum marginale, we aim to explore the therapeutic bioactivity potentiality and its prime role in improvising and searching for potential alternatives for seizing Diabetes mellitus. Materials and Methods: The antioxidant activity of Nitophyllum marginale was evaluated using ABTS, DPPH, nitric oxide, lipid peroxidation, and hydrogen peroxide assays. Additionally, alphaglucosidase inhibition tests were conducted to evaluate the potential as an antidiabetic agent. Results: The study revealed that extracts from Nitophyllum marginale contain antioxidants that protect cells from oxidative stress. These extracts also contain bioactive compounds like alkaloids, flavonoids, phenols, saponins, and carbohydrates. These compounds work together to provide antioxidant benefits. Additionally, the extracts showed activity against alpha-glucosidase, which is vital for managing blood sugar levels. Conclusion:: These results emphasize the existence of bioactive metabolites exhibiting phytochemicals, antioxidants, and antidiabetic activities obtained from the extract using chloroform and methanol solvents. These findings suggest the potential of Nitophyllum marginale extracts as a natural reservoir of antioxidants and antidiabetic agents.

Evaluation of a qualified MDCK cell line for virus isolation to develop cell-based influenza vaccine viruses with appropriate antigenicity

We established a qualified Madin-Darby canine kidney cell line (qMDCK-Cs) and investigated its suitability for source virus isolation to develop cell-based seasonal influenza vaccine viruses using vaccine manufacturer cells (Manuf-Cs). When inoculated with 81 influenza-positive clinical specimens, the initial virus isolation efficiency of qMDCK-Cs was exceeded 70%. Among the qMDCK-C isolates, 100% of the A/H1N1pdm09, B/Victoria and B/Yamagata strains and >70% of the A/H3N2 strains showed antigenicity equivalent to that of the contemporary vaccine or relevant viruses in haemagglutination inhibition (HI) or virus neutralization (VN) tests using ferret antisera. These qMDCK-C isolates were propagated in Manuf-Cs (MDCK and Vero cells) (Manuf-C viruses) to develop vaccine viruses. In reciprocal antigenicity tests, ferret antisera raised against corresponding reference viruses and Manuf-C viruses recognized 29 of 31 Manuf-C viruses and corresponding reference viruses, respectively at HI or VN titres more than half of the homologous virus titres, which is the antigenicity criterion for cell culture seasonal influenza vaccine viruses specified by the World Health Organization. Furthermore, ferret antisera against these Manuf-C viruses recognized ≥95% of the viruses circulating during the relevant influenza season with HI or VN titres greater than one-quarter of the homologous virus titres. No cell line-specific amino acid substitutions were observed in the resulting viruses. However, polymorphisms at positions 158/160 of H3HA, 148/151 of N2NA and 197/199 of B/Victoria HA were occasionally detected in the qMDCK-C and Manuf-C viruses but barely affected the viral antigenicity. These results indicated that qMDCK-Cs are suitable for isolating influenza viruses that can serve as a source of antigenically appropriate vaccine viruses. The use of the qMDCK-C isolates will eliminates the need for clinical sample collection, virus isolation, and antigenicity analysis every season, and is expected to contribute to the promotion of vaccine virus development using manufacturer cells.

Accumulation of mitochondrial DNA with a point mutation in tRNALeu(UUR) gene induces brain dysfunction in mice

Brain functions are mediated via the complex interplay between several complex factors, and hence, identifying the underlying cause of an abnormality within a certain brain region can be challenging. In mitochondrial disease, abnormalities in brain function are thought to be attributed to accumulation of mitochondrial DNA (mtDNA) with pathogenic mutations; however, only few previous studies have directly demonstrated that accumulation of mutant mtDNA induced abnormalities in brain function. Herein, we examined the effects of mtDNA mutations on brain function via behavioral analyses using a mouse model with an A2748G point mutation in mtDNA tRNALeu(UUR). Our results revealed that mice with a high percentage of mutant mtDNA showed a characteristic trend toward reduced prepulse inhibition and memory-dependent test performance, similar to that observed in psychiatric disorders, such as schizophrenia; however, muscle strength and motor coordination were not markedly affected. Upon examining the hippocampus and frontal lobes of the brain, mitochondrial morphology was abnormal, and the brain weight was slightly reduced. These results indicate that the predominant accumulation of a point mutation in the tRNALeu(UUR) gene may affect brain functions, particularly the coordination of sensory and motor functions and memory processes. These abnormalities probably caused by both direct effects of accumulation of the mutant mtDNA in neuronal cells and indirect effects via changes of systemic extracellular environments. Overall, these findings will lead to a better understanding of the pathogenic mechanism underlying this complex disease and facilitate the development of optimal treatment methods.

Establishment of a Flow-Through System for the Macrophyte Growth Inhibition Test (OECD 239) Including Photosynthetic Activity Measurement to Determine Early Effects.

Maintaining constant exposure concentrations during ecotoxicological studies while testing rapidly degradable substances is a challenge. To achieve stable concentrations during exposure, flow-through systems are used. To assess the impact of substances on higher aquatic plants, the 14-day macrophyte water-sediment Myriophyllum spicatum growth inhibition test (Organisation for Economic Co-operation and Development [OECD, 2014a] test guideline 239) only includes a static or a semistatic test design. The main aim of our study was to investigate the applicability of a flow-through system for M. spicatum. The standard OECD test design was miniaturized, and a flow-through system with spill-over was developed to achieve stable exposure concentrations of a rapidly degrading substance. The main endpoints were total shoot length and fresh and dry weight. Photosynthetic activity was used as an endpoint for the identification of early effects using the noninvasive Image-Producing Pulse Amplitude Modulation (IMAGING-PAM) procedure. Atorvastatin (AV; fast degrading) and bentazone (BT; photosynthesis inhibitor) were used as model substances to observe differences of the effect concentration depending on the test design. At higher exposure levels of AV, stronger necrosis combined with lower effect concentrations was observed in the flow-through test compared with the semistatic test, indicating the applicability of the flow-through test for evaluating degradable substances. The test with BT demonstrated a concentration-dependent decrease in the photosynthetic yield (Y(II)) from day 3 onward even before macroscopically visible changes occurred. Our results show that the flow-through system in the macrophyte growth inhibition test (OECD test guideline 239; 2014a) is a suitable alternative when one is testing rapidly degradable substances such as AV. In addition, we showed that photosynthetic yield can serve as a supplementary endpoint, when one is testing substances with photosynthesis inhibition as a mode of action. Environ Toxicol Chem 2024;00:1-12. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.