Solid Growth Media Research Articles

Maximum likelihood estimators for colony-forming units.

Measuring the abundance of microbes in a sample is a common procedure with a long history, but best practices are not well-conserved across microbiological fields. Serial dilution methods are commonly used to dilute bacterial cultures to produce countable numbers of colonies, and from these counts, to infer bacterial concentrations measured in colony-forming units (CFUs). The most common methods to generate data for CFU point estimates involve plating bacteria on (or in) a solid growth medium and counting their resulting colonies or counting the number of tubes at a given dilution that have growth. Traditionally, these types of data have been analyzed separately using different analytic methods. Here, we build a direct correspondence between these approaches, which allows one to extend the use of the most probable number method from the liquid tubes experiments, for which it was developed, to the growth plates by viewing colony-sized patches of a plate as equivalent to individual tubes. We also discuss how to combine measurements taken at different dilutions, and we review several ways of analyzing colony counts, including the Poisson and truncated Poisson methods. We test all point estimate methods computationally using simulated data. For all methods, we discuss their relevant error bounds, assumptions, strengths, and weaknesses. We provide an online calculator for these estimators.Estimation of the number of microbes in a sample is an important problem with a long history. Yet common practices, such as combining results from different measurements, remain sub-optimal. We provide a comparison of methods for estimating abundance of microbes and detail a mapping between different methods, which allows to extend their range of applicability. This mapping enables higher precision estimates of colony-forming units (CFUs) using the same data already collected for traditional CFU estimation methods. Furthermore, we provide recommendations for how to combine measurements of colony counts taken across dilutions, correcting several misconceptions in the literature.

Quantifying massively parallel microbial growth with spatially mediated interactions.

Quantitative understanding of microbial growth is an essential prerequisite for successful control of pathogens as well as various biotechnology applications. Even though the growth of cell populations has been extensively studied, microbial growth remains poorly characterised at the spatial level. Indeed, even isogenic populations growing at different locations on solid growth medium typically show significant location-dependent variability in growth. Here we show that this variability can be attributed to the initial physiological states of the populations, the interplay between populations interacting with their local environment and the diffusion of nutrients and energy sources coupling the environments. We further show how the causes of this variability change throughout the growth of a population. We use a dual approach, first applying machine learning regression models to discover that location dominates growth variability at specific times, and, in parallel, developing explicit population growth models to describe this spatial effect. In particular, treating nutrient and energy source concentration as a latent variable allows us to develop a mechanistic resource consumer model that captures growth variability across the shared environment. As a consequence, we are able to determine intrinsic growth parameters for each local population, removing confounders common to location-dependent variability in growth. Importantly, our explicit low-parametric model for the environment paves the way for massively parallel experimentation with configurable spatial niches for testing specific eco-evolutionary hypotheses.

Growth and no-growth boundary of Clostridium perfringens in cooked cured meats – A logistic analysis and development of critical control surfaces using a solid growth medium

This study was conducted to evaluate the effect of sodium nitrite (NaNO2, 100–200 ppm), sodium erythorbate (SE, 0–547 ppm), sodium tripolyphosphate (STPP, 0–0.5 %), and sodium chloride (NaCl, 2–3 %) on growth of C. perfringens using a solid growth medium and to develop a growth/no-growth boundary (critical control surface, or CCS) to prevent its growth in cooked cured meat under the optimal temperature condition. Melted Shahidi Ferguson Perfringens (SFP) agar, inoculated with a 3-strain spore cocktail and mixed with NaNO2, SE, STPP, and NaCl according to a Box-Behnken response surface experimental design, was dispersed in 96-well microplates and incubated anaerobically in an incubator programmed to remain at 4 °C for 24 h, heat to 80 °C in 1.75 h, quickly (0.5 h) cool to 46 °C (optimum temperature), and then maintain at 46 °C overnight. The plates were examined optically and visually for colony formation. Any well free of growth was designated as no-growth. Logistic regression was used to analyze the growth probability (P) as affected by NaNO2, SE, STPP, and NaCl and define a CSS as meeting the criterion of P < 1/96. The results showed that STPP and the interactions of SE with NaNO2 and NaCl could reduce the growth probability of C. perfringens in SFP agar. The validation of CCS with ground beef showed an accuracy of 96.3 % for no growth of C. perfringens in the inoculated samples. The results of this study proved that cured meat can be formulated with proper combinations of NaNO2, SE, STPP, and NaCl to prevent the growth of C. perfringens even under the optimum temperature condition, thus preventing food poisoning caused by the growth of this microorganism.

Characterization, Comparative Assessment and Antibacterial Potential of Copper(II) Soya Complexes against Staphylococcus Aureus

Copper(II) soap complexes have been proven their activity against bacteria very effectively. Herein, the influence of biophysical and biomechanical parameters on the activity of Copper(II) soya thiourea complex was evaluated. To this aim, liquid as well as solid growth media were developed by Kirby-Bauer disc diffusion method. The antibacterial activity of Copper(II) soya thiourea complex against the Gram-positive bacterium Staphylococcus aureus was assessed in various concentration of Copper(II) Soya complexes. Copper (II) Soya complexes also resist bacterial growth at higher concentration. This review provides a board overview of Staphylococcus aureus with an emphasis on the Copper(II) soya thiourea complex

Are high-throughput root phenotyping platforms suitable for informing root system architecture models with genotype-specific parameters? An evaluation based on the root model ArchiSimple and a small panel of wheat cultivars.

Given the difficulties in accessing plant roots in situ, high-throughput root phenotyping (HTRP) platforms under controlled conditions have been developed to meet the growing demand for characterizing root system architecture (RSA) for genetic analyses. However, a proper evaluation of their capacity to provide the same estimates for strictly identical root traits across platforms has never been achieved. In this study, we performed such an evaluation based on six major parameters of the RSA model ArchiSimple, using a diversity panel of 14 bread wheat cultivars in two HTRP platforms that had different growth media and non-destructive imaging systems together with a conventional set-up that had a solid growth medium and destructive sampling. Significant effects of the experimental set-up were found for all the parameters and no significant correlations across the diversity panel among the three set-ups could be detected. Differences in temperature, irradiance, and/or the medium in which the plants were growing might partly explain both the differences in the parameter values across the experiments as well as the genotype × set-up interactions. Furthermore, the values and the rankings across genotypes of only a subset of parameters were conserved between contrasting growth stages. As the parameters chosen for our analysis are root traits that have strong impacts on RSA and are close to parameters used in a majority of RSA models, our results highlight the need to carefully consider both developmental and environmental drivers in root phenomics studies.

Analysis of CenKR essentiality in Sinorhizobium meliloti and its activity at a target gene promoter in vivo.

The two-component regulatory system CenK-CenR has recently emerged as a regulator of cell envelope and cell division processes in the alpha-proteobacteria. In Sinorhizobium meliloti, CenK-CenR regulates the expression of SrlA, a thioredoxin-domain protein of unknown function. Deletion of srlA causes sensitivity to salt and oxidizing agents on solid growth medium. In this work, we report that the response regulator CenR, but not the histidine kinase CenK, is essential for cell viability in S. meliloti. We also demonstrate that phosphorylation of the target residue D55 is not required for viability, suggesting that the unphosphorylated transcription factor sufficiently regulates expression of one or more essential genes in the genome. Using transcription assays and phenotype testing we examine CenK-CenR-dependent activation of the srlA promoter and demonstrate its absolute dependence on phosphoryl-CenR for activity and that the CenR substitution D55E acts as a phosphomimetic that partially restores activity at the srlA promoter in the absence of phosphorylation by CenK. Finally, we report a mutational analysis of the CenR binding site in the srlA promoter required for transcriptional activation.

Polyethylene glycol as an improved barrier to prevent fleeing in C. elegans.

Caenorhabditis elegans studies can be constrained by worms escaping standard solid nematode growth medium (NGM) plates. When worms are in search of food or are avoiding pathogens, chemicals, and environmental stressors, they often exhibit a behavior known as "fleeing". Palmitic acid (PA) is sometimes used as a barrier "fence" to reduce fleeing under limited food and oxygen conditions. Here, we evaluate the efficacy of palmitic acid, polyethylene glycol (PEG) and copper as potential barriers to reduce fleeing under various environmental conditions. Our results indicate that PA and PEG each reduce fasted flee rate and do not obviously alter overall health and lifespan of the worms, while copper blunts worm growth and development. We also find that PEG is a more optimal tool than PA since it is more effective in fasted conditions, reduces flee rate in a pathogenic environment, and does not alter worm size.

Modern opportunities of etiologic diagnosis of tuberculous spondylitis (Pott’s disease) in patients with combined viral infections

Purpose. Improvement of algorithms of etiologic diagnostics of tuberculous spondylitis in modern realities of mycobacteria drug resistance and combined viral infections.Materials and methods. Laboratory results of diagnostic materials obtained from 300 patients diagnosed with tuberculous spondylitis were analyzed; patients were divided into groups according to the presence of HIV and hepatitis C virus (HCV): 20% of patients had no viral infections, 8% of patients were infected with HCV only, 6% were infected with HIV only; 66% of patients were infected with both HIV and HCV. The surgical bone material was examined by the classical triad of etiologic diagnostics of tuberculosis – microscopy, culture on solid growth media and molecular genetic methods (PCR).Results. Molecular genetic methods are the most informative methods for diagnosing tuberculous spondylitis – the detection rate of MBT is 83%(p&lt; 0.001). Thesemethodsshouldbethemainonesinthestudyofbiologicalmaterialfrompatientsdiagnosedwithtuberculousspondylitis, while bacteriological methods should be used to verify the diagnosis. MBTs isolated from patients with co-infections are characterized by a wide spectrum of drug resistance: the presence of HIV in patients with tuberculous spondylitis 4.16 times (95% CI 2.11-7.67) increased the chance that mycobacteria in the focus of lesions are resistant to at least rifampicin and isoniazid, and the presence of HCV – 2.29 times (95% CI 1.364.86). Therefore, if viral infections are present in a patient with TC, he/she should be considered as a patient at risk of MDR/XDR TB and an appropriate chemotherapy regimen should be administered even in the absence of bacteriologic results.

Decolorization potential of malachite green by Ralstonia mannitolilytica isolated from Indonesian cassava-based fermentedfoodtapai.

Pollution due to textile dye effluent mishandling is hazardous to ecosystems and to the living beings inhabiting them. This can cause retarded photosynthesis, disrupted fish day/night cycles, unbalanced bacterial populations, and decreased oxygen concentration in contaminated water, leading to low habitability. In this study, we aimed to isolate and characterize the microorganisms found in Indonesian cassava-based fermented food tapai starter cultures as a source of potential microbes for the biological remediation of textile dye pollutants. Microorganisms in the tapai starter culture were screened for their decolorization activity via spread-culture inoculation on a solid growth medium supplemented with textile dyes. Isolated microorganisms were selected based on their ability to secrete textile dye-decolorizing extracellular enzymes via increased light penetration after incubation of the cell-free supernatant (CFS) containing extracellular enzymes in textile dye solutions. Isolate JSP1 was the only bacterium capable of producing malachite green (MG)-decolorizing extracellular enzymes, which enabled it to survive and decolorize MG up to 375ppm. Moreover, isolate JSP1 CFS was able to optimally decolorize 75% of MG at 100ppm, but its activity was diminished at concentrations > 350ppm. Colony and cellular morphology, biochemistry, and 16S rRNA tests revealed that the isolate was of Ralstonia mannitolilytica. Therefore, R. mannitolilytica isolate JSP1 may be a potential bioremediation agent for MG.

A study on twitching motility dynamics in Ralstonia solanacearum microcolonies by live imaging.

Ralstonia solanacearum is a rod-shaped phytopathogenic bacterium that causes lethal wilt disease in many plants. On solid agar growth medium, in the early hour of the growth of the bacterial colony, the type IV pili-mediated twitching motility, which is important for its virulence and biofilm formation, is prominently observed under the microscope. In this study, we have done a detailed observation of twitching motility in R. solanacearum colony. In the beginning, twitching motility in the microcolonies was observed as a density-dependent phenomenon that influences the shape of the microcolonies. No such phenomenon was observed in Escherichia coli, where twitching motility is absent. In the early phase of colony growth, twitching motility exhibited by the cells at the peripheral region of the colony was more prominent than the cells toward the center of the colony. Using time-lapse photography and merging the obtained photomicrographs into a video, twitching motility was observed as an intermittent phenomenon that progresses in layers in all directions as finger-like projections at the peripheral region of a bacterial colony. Each layer of bacteria twitches on top of the other and produces a multilayered film-like appearance. We found that the duration between the emergence of each layer diminishes progressively as the colony becomes older. This study on twitching motility demonstrates distinctly heterogeneity among the cells within a colony regarding their dynamics and the influence of microcolonies on each other regarding their morphology.

Polysaccharides of &lt;i&gt;Crotalaria alata&lt;/i&gt; and &lt;i&gt;Gleditsia triacanthos&lt;/i&gt; as Components of a Growth Medium for Cultivation of Microfungi

Abstract—The study explores the possibility of using the seeds of Crotalaria alata L. and Gleditsia triacanthos L. (Fabaceae) as a growth medium stabilizer for cultivation of microfungi. A synergistic effect was achieved when agar-agar was combined with galactomannans from Crotalaria alata and Gleditsia triacanthos, in a ratio of 1.5 : 4 : 1. Such a composition made it possible to obtain a solid growth medium, similar in consistency and color to 2% agar-agar medium. To establish biological parameters of the developed medium, the spores of microfungi Stachybotrys alternans Bonord. (Stachybotrys Cordа) и Fusarium oxysporum Schr f. vasinfectum Bilai (Fusarium), were plated on the surface of the growth media using inoculation needle and incubated in a thermostat at 25–26 °C. It was shown that partial substitution of agar-agar with galactomannans contributes to the active growth of the microorganisms. The growth of the Stachybotrys alternans and Fusarium oxysporum fungal colonies on the galactomannans growth medium surpassed the control on the fifth day by 37.2 and 31.5%, and on the seventh day – by 8.7 and 11.1% respectively.

An extended catalogue of ncRNAs in Streptomyces coelicolor reporting abundant tmRNA, RNase-P RNA and RNA fragments derived from pre-ribosomal RNA leader sequences

Streptomyces coelicolor is a model organism for studying streptomycetes. This genus possesses relevant medical and economical roles, because it produces many biologically active metabolites of pharmaceutical interest, including the majority of commercialized antibiotics. In this bioinformatic study, the transcriptome of S. coelicolor has been analyzed to identify novel RNA species and quantify the expression of both annotated and novel transcripts in solid and liquid growth medium cultures at different times. The major characteristics disclosed in this study are: (i) the diffuse antisense transcription; (ii) the great abundance of transfer-messenger RNAs (tmRNA); (iii) the abundance of rnpB transcripts, paramount for the RNase-P complex; and (iv) the presence of abundant fragments derived from pre-ribosomal RNA leader sequences of unknown biological function. Overall, this study extends the catalogue of ncRNAs in S. coelicolor and suggests an important role of non-coding transcription in the regulation of biologically active molecule production.

Generation of miniploid cells and improved natural transformation procedure for a model cyanobacterium Synechococcus elongatus PCC 7942.

The biotechnologically important and naturally transformable cyanobacterium, Synechococcus elongatus PCC 7942, possesses multiple genome copies irrespective of its growth rate or condition. Hence, segregating mutations across all genome copies typically takes several weeks. In this study, Synechococcus 7942 cultivation on a solid growth medium was optimised using different concentrations of agar, the addition of antioxidants, and overexpression of the catalase gene to facilitate the rapid acquisition of colonies and fully segregated lines. Synechococcus 7942 was grown at different temperatures and nutritional conditions. The miniploid cells were identified using flow cytometry and fluorimetry. The natural transformation was carried out using miniploid cells and validated with PCR and high performance liquid chromatography (HPLC). We identified that 0.35% agar concentration and 200 IU of catalase could improve the growth of Synechococcus 7942 on a solid growth medium. Furthermore, overexpression of a catalase gene enhanced the growth rate and supported diluted culture to grow on a solid medium. Our results reveal that high temperature and phosphate-depleted cells contain the lowest genome copies (2.4 ± 0.3 and 1.9 ± 0.2) and showed the potential to rapidly produce fully segregated mutants. In addition, higher antibiotic concentrations improve the selection of homozygous transformants while maintaining similar genome copies at a constant temperature. Based on our observation, we have an improved cultivation and natural transformation protocol for Synechococcus 7942 by optimising solid media culturing, generating low-ploidy cells that ultimately reduced the time required for the complete segregation of engineered lines.

High-throughput Method for Novel Medium Development for Culture of Anaerobic Gut Bacteria.

Gut microbiota play important roles in the health of their host and detailed investigation of these organisms requires in vitro culture. Culturing strictly anaerobic bacteria can be a challenge as the gut environment they inhabit is nutritionally complex. Use of complex media containing nutritionally rich but undefined gut fluid reduces the accuracy of physiological and metabolomic studies. Here we present a high-throughput protocol for comparing growth rates of fastidiously anaerobic bacteria on different media. These protocols can be used to develop a solid medium made up of commercially sourced ingredients, providing replicable growth conditions for previously uncultured anaerobic bacteria. As many fastidious bacteria grow poorly in a liquid broth, these protocols measure bacterial growth rate on solid media. These protocols speed up and simplify the growth rate measurement process by using a multiwell format and equations in place of physical McFarland standards to calculate approximate cell density. Bacterial strains belonging to the families Erysipelotrichaceae and Lachnospiraceae (phylum Firmicutes) isolated from the hindgut of Kyphosus sydneyanus were used to demonstrate the efficacy of these protocols. Bacterial growth rates were compared between a nutritionally rich medium with gut fluid versus a novel replicable medium with mannitol. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Preparation of solid YCFA growth medium Basic Protocol 2: Collection of fish gut samples and plating to single isolates Basic Protocol 3: Genetic identification of single isolates with colony PCR and 16S rRNA gene sequencing Basic Protocol 4: Measurement of bacterial growth rates on solid media.

Development and Study of Bacteriophage-containing Dosage Form for the Treatment of the Outer Ear Infections

Introduction. Infectious otitis externa and middle ear can cause hearing loss, which significantly reduces the quality of life of patients. The main causative agents of acute bacterial otitis media are Pseudomonas aeruginosa and Staphylococcus aureus. This article is devoted to the development and study of a novel dosage form for treatment of infectious diseases of the external ear containing bacteriophages that lyse bacterial strains of Pseudomonas aeruginosa. Ear drops were considered as a promising dosage form for instillation into the ear canal.Aim. The aim of the work is to develop a dosage form of Pseudomonas aeruginosa bacteriophages for the local treatment of infectious otitis media.Materials and Methods. The active substances of the developed drug are bacteriophages that lyse bacterial strains of Pseudomonas aeruginosa: PA5 and PA10, which were obtained by growing on a solid growth medium in mattress flasks with subsequent sterilizing filtration through a membrane filter (0,22 µm) and elimination of endotoxins on a chromatographic column. To obtain experimental compositions, excipients that do not cause a drop in the titer of bacteriophages were used – purified water as the solvent, viscosity modifiers: glycerol (CHIMMED, Russia) and a mix of macrogol 6 and glyceryl caprilocaprate brand Softigen 767 (Cremer, Germany), antioxidant Ethylenediaminetetraacetic acid (EDTA), preservatives nipagin and nipazole. The obtained samples were standardized according to pharmacopoeial indicators, recommended for the dosage form "drops" – density, pH, viscosity. For all experimental compositions, the stability of the titer of bacteriophages was studied by the Gratia method for 6 months. The local irritation and systemic effects were also studied on five chinchilla male rabbits.Results and discussion. As a result of the conducted research, four experimental compositions of ear drops with a cocktail of bacteriophages PA5 and PA10 were obtained. The optimal technological characteristics were observed in the composition containing glycerol as a viscosity modifier at a concentration of 10,0 %. For optimal composition, the stability of the bacteriophages cocktail titer, local irritating and systemic effects were analyzed. The study revealed stability of the bacteriophages PA5 and PA10 titers in the composition of dosage form, and absence of local irritating and systemic effects of ear drops.Conclusion. The dosage form can be recommended for preclinical studies.

Rapid printing of a Bacterial array for a Solid-Phase Assay (BacSPA) of heavy metal ions

Bacterial whole-cell biosensors have been used to detect numerous pollutants for decades. In this work, a rapid sensing method using patterned bacterial arrays on solidified agar media was reported. A printing system, which quickly patterns 384-spot bacterial arrays via inertial impact, was developed in this study. The droplet formation was observed by a high-speed camera and simulated in COMSOL software to investigate the printing conditions. We found that the droplet volume and speed were influenced by the accelerations of the impact. Following adjustment, the printer could eject discrete droplets and pattern arrays with high accuracy. The printed bacteria were incubated, and images acquired by a commercial digital camera were analyzed by the Python program. The areas of 384 spots in a single array were similar, with a high roundness and low deviations. We found that the printer plate quality influenced the printing results more than the printing conditions. Finally, the printing system was applied to determine heavy metals concentrations in solid growth media by bioluminescent sensor bacteria. The luminescence intensity patterns varied between heavy metals. We propose the printing system as a useful tool for rapid patterning of bacterial whole cell sensor arrays on solid agar.

Infrared thermography can detect previsual bacterial growth in a laboratory setting via metabolic heat detection.

AimsDetection of bacterial contamination in healthcare and industry takes many hours if not days. Thermal imaging, the measurement of heat by an infrared camera, was investigated as a potential noninvasive method of detecting bacterial growth.Methods and ResultsInfrared thermography can detect the presence of Escherichia coli and Staphylococcus aureus on solid growth media by an increase in temperature before they are visually observable. A heat decrease is observed after treatment with ultraviolet light and heat increased after incubation with dinitrophenol.ConclusionsInfrared thermography can detect early growth of bacteria before they are detectable by other microbiology‐based method. The heat observed is due to the cells being viable and metabolically active, as cells killed with ultraviolet light exhibit reduced increase in temperature and treatment with dinitrophenol increases heat detected.Significance and Impact of the StudyInfrared thermography detects bacterial growth without the need for specialized temperature control facilities. The method is statistically robust and can be undertaken in situ, thus is highly versatile. These data support the application of infrared thermography in a laboratory, clinical and industrial setting for vegetative bacteria, thus may become into an important methodology for the timely and straightforward detection of early‐stage bacterial growth.

Differentiation of Saccharomyces species by lipid and metabolome profiles from a single colony

Yeast metabolism depends on growing conditions, which include the chemical composition of the medium, temperature and growth time. Historically, fatty acid profiles have been used to differentiate yeasts growing in liquid media. The present study determined the fatty acids of Saccharomyces species in colonies. Using the same method, the effect of that the number of colonies and growth time had on solid media allowed us to determine the metabolomic profiles of the cells. Our results showed that the lipid and metabolomic profiles of the cells evolved as the colony grew. Interestingly, some strains of Saccharomyces cerevisiae have been were differentiated using the fatty acid profile of a colony; concretely indeed EC1118 and QA23 strains were separated from ICV-K1 and BM4x4. The synthesis of saturated fatty acids was greater than that of unsaturated fatty acids during the first two days of cell growth on a solid medium compared to a liquid medium. Unsaturated fatty acids subsequently became predominant. Finally, this methodology could be useful for carrying out physiological studies in a complete or defined solid growth medium allowing the supplementation of compounds, which inhibit or activate the growth of yeasts.

Comparing Bactericidal Effect of Pulsed Flash Lamp and Continuous Sterilization UV Lamps with a Cold Atmospheric Pressure Plasma Jet on E. Coli Solid Growth Medium

Comparing Bactericidal Effect of Pulsed Flash Lamp and Continuous Sterilization UV Lamps with a Cold Atmospheric Pressure Plasma Jet on E. Coli Solid Growth Medium

Deer antler extracts reduce amyloid-beta toxicity in a Caenorhabditis elegans model of Alzheimer's disease

Ethnopharmacological relevanceVelvet antler extracts (VAE) are composed of a variety of active substances and growth factors, and have been reported to improve sleep quality and memory. Aim of the studyWe aimed to explore the protective effects and mechanism of action for VAE on Alzheimer's disease (AD) using a transgenic Caenorhabditis elegans model. Materials and methodsC. elegans were cultivated at 40% relative humidity on solid nematode growth medium (NGM) containing live E. coli (OP50) as the food source, with Strain N2 (normal) held at 20 °C and the CL4176s (transgenic) held at 16 °C. AD-like aggregation of Aβ peptide in the CL4176s strain is induced by lifting the temperature to 25 °C. Nematodes were treated with three types of VAEs and Resveratrol (positive control). Analyses included qRT-PCR for quantification of gene transcripts of interest; ELISA for measuring levels of amyloid-β protein; Thioflavin T fluorescent staining for localizing Aβ depositions; assays for reactive oxygen species (ROS) and superoxide dismutase activity (SOD). ResultsVAEs reduced β-amyloid peptide (Aβ) toxicity in the transgenic C. elegans model. An enzymatically-digested VAE (EDVAE) was superior to both a cold-water VAE (CWVAE) and a hot-water VAE (HWVAE) from the same velvet antler. EDVAE treatment reduced the severity of the Aβ-induced paralysis phenotype and decreased the amount of Aβ deposits in the AD model nematodes, and these effects were found to be significantly better than that of the positive control Resveratrol. In addition, EDVAE treatment reduced production of ROS (induced by Aβ), enhanced SOD activity, and elevated expression levels of antioxidant-related transcription factors, although it is not known whether these effects were achieved directly or indirectly. ConclusionEDVAE had a protective role in Aβ-induced toxicity in the transgenic AD nematodes, possibly through reducing accumulation of toxic Aβ and enhancing the ability of nematodes to resist oxidative stress. Thus, EDVAE has potential to be an effective treatment to relieve the symptoms of AD.