Submerged fermentation of lentil protein isolate and its impact on protein functionality, nutrition, and volatile profiles.

Fermentation of pulses as a clean processing technique has been reported to have a favorable impact on the functional and nutritional quality of the starting materials. Compared to commonly fermented pulses such as peas and chickpeas, limited information is available on the effect of fermentation on lentils, especially when using a high protein isolate (>80% protein) as compared to seeds or flours. Therefore, in the present work, lentil protein isolate was used as a feedstock for submerged fermentation with Aspergillus niger, Aspergillus oryzae, or Lactobacillus plantarum. After 48 h, the samples showed increased protein content with enhanced solubility and oil-holding capacity. Controlled fermentation, as opposed to spontaneous fermentation, maintained the high foaming capacity; however, all fermented samples had lower foam and emulsion stabilizing properties and reduced water-holding capacity compared to the control. The fermented proteins were also less digestible, possibly due to an increase in phenolics and saponins. New volatile compounds were identified in fermented samples that show promise for improved sensory attributes. Significant differences were observed in specific quality attributes depending on the microbial strain used. Further research is required to better understand the fermentative metabolism of microbial communities when provided high-protein lentil ingredients as growth substrates. PRACTICAL APPLICATION: Fermented lentil protein isolate has promising flavor profiles that may improve its sensory properties for food application.

Sub-MIC antibiotics influence the microbiome, resistome and structure of riverine biofilm communities.

The effects of sub-minimum inhibitory concentrations (sub-MICs) of antibiotics on aquatic environments is not yet fully understood. Here, we explore these effects by employing a replicated microcosm system fed with river water where biofilm communities were continuously exposed over an eight-week period to sub-MIC exposure (1/10, 1/50, and 1/100 MIC) to a mix of common antibiotics (ciprofloxacin, streptomycin, and oxytetracycline). Biofilms were examined using a structure-function approach entailing microscopy and metagenomic techniques, revealing details on the microbiome, resistome, virulome, and functional prediction. A comparison of three commonly used microbiome and resistome databases was also performed. Differences in biofilm architecture were observed between sub-MIC antibiotic treatments, with an overall reduction of extracellular polymeric substances and autotroph (algal and cyanobacteria) and protozoan biomass, particularly at the 1/10 sub-MIC condition. While metagenomic analyses demonstrated that microbial diversity was lowest at the sub-MIC 1/10 antibiotic treatment, resistome diversity was highest at sub-MIC 1/50. This study also notes the importance of benchmarking analysis tools and careful selection of reference databases, given the disparity in detected antimicrobial resistance genes (ARGs) identity and abundance across methods. Ultimately, the most detected ARGs in sub-MICs exposed biofilms were those that conferred resistance to aminoglycosides, tetracyclines, ß-lactams, sulfonamides, and trimethoprim. Co-occurrence of microbiome and resistome features consistently showed a relationship between Proteobacteria genera and aminoglycoside ARGs. Our results support the hypothesis that constant exposure to sub-MICs antibiotics facilitate the transmission and promote prevalence of antibiotic resistance in riverine biofilms communities, and additionally shift overall microbial community metabolic function.

Impact of Raised without Antibiotics Measures on Antimicrobial Resistance and Prevalence of Pathogens in Sow Barns.

The growing concern over the emergence of antimicrobial resistance (AMR) in animal production as a result of extensive and inappropriate antibiotic use has prompted many swine farmers to raise their animals without antibiotics (RWA). In this study, the impact of implementing an RWA production approach in sow barns on actual on-farm antibiotic use, the emergence of AMR, and the abundance of pathogens was investigated. Over a 13-month period, fecal and nasopharynx samples were collected at 3-month intervals from sows raised in RWA barns and sows in conventional barns using antibiotics in accordance with the new regulations (non-RWA). Whole genome sequencing (WGS) was used to determine the prevalence of AMR and the presence of pathogens in those samples. Records of all drug use from the 13-month longitudinal study indicated a significant reduction in antimicrobial usage in sows from RWA barns compared to conventional non-RWA barns. Antifolates were commonly administered to non-RWA sows, whereas ß-lactams were widely used to treat sows in RWA barns. Metagenomic analyses demonstrated an increased abundance of pathogenic Actinobacteria, Firmicutes, and Proteobacteria in the nasopharynx microbiome of RWA sows relative to non-RWA sows. However, WGS analyses revealed that the nasal microbiome of sows raised under RWA production exhibited a significant increase in the frequency of resistance genes coding for ß-lactams, MDR, and tetracycline.

Huddling together to survive: Population density as a survival strategy of non-spore forming bacteria under nutrient starvation and desiccation at solid-air interfaces.

Acclimation and flexible response mechanisms are survival adaptations allowing prokaryotic cells to colonize diverse habitats and maintain viability in nature. Lack of water significantly impacts cellular response, which can be partially compensated for through community interactions and accessing survival means beyond the cell's boundaries. In the present study, higher numbers of cultivable Gram-positive Arthrobacter sp. and Gram-negative Pseudomonas stutzeri cells were found on surfaces when high population density was used after prolonged periods of desiccation and nutrient starvation. Total cell counts during desiccation periods decreased slower than culturable cell counts independently from initial population density. The presence of homogenate, prepared by filtering homogenized cultures through a 0.2 µm filter, extended culturability of Arthrobacter sp. cells, while intact heat-killed cells extended the culturability of Arthrobacter sp. and P. stutzeri. Our results suggest very slow cell membrane breakdown for desiccated bacterial cells at solid-air interfaces over extended time spans, which may serve as reservoirs of nutrients, and may potentially provide trace amounts of water for surviving cells. Higher initial population density and recycling of resources from "zombie"-like cells, may support growth in a similar fashion as access to cell lysates or the contents of heat-killed cells analogous to dead-phase cultures where some cells experience cryptic growth.

Draft Genome Sequence of Polaromonas eurypsychrophila AER18D-145, Isolated from a Uranium Tailings Management Facility in Northern Saskatchewan, Canada.

The 4.8-Mbp draft genome sequence of Polaromonas eurypsychrophila AER18D-145, isolated from a uranium tailings management facility, is reported. The sequence may provide insights into the mechanisms of the hypertolerance of this strain to extreme conditions and help determine its potential for bioremediation applications.

Multilayer photonic films based on interlocked chiral-nematic cellulose nanocrystals in starch/chitosan.

In this study, a new approach to employ and control cellulose nanocrystal (CNC) chiral nematic structure as a biodegradable, intelligent material was investigated. Tuned CNC self-assembled films were interlocked between two layers of citric acid, cross-linked starch/chitosan (1:1) films through the solvent casting process. This method increased the mechanical properties of produced films and created a selective reflection band from UV to near-IR depending on the helical pitch of the chiral nematic CNC layer. The features of these intelligent films have potential for different applications, from UV protective packaging to biomedical uses. The water vapor permeability (WVP) of the produced films decreased considerably by adding a CNC layer into the cross-linked starch/chitosan structure. Also, the WVP was different for the different helical pitches of the CNC layer. The starch/chitosan (outer layer) also showed a remarkable antibacterial property against E. coli, P. fluorescens, S. Enteritidis, and S. aureus which could be useful for biomedical applications or antibacterial packaging.

Environmental Biofilms as Reservoirs for Antimicrobial Resistance.

Characterizing the response of microbial communities to a range of antibiotic concentrations is one of the strategies used to understand the impact of antibiotic resistance. Many studies have described the occurrence and prevalence of antibiotic resistance in microbial communities from reservoirs such as hospitals, sewage, and farm feedlots, where bacteria are often exposed to high and/or constant concentrations of antibiotics. Outside of these sources, antibiotics generally occur at lower, sub-minimum inhibitory concentrations (sub-MICs). The constant exposure to low concentrations of antibiotics may serve as a chemical "cue" that drives development of antibiotic resistance. Low concentrations of antibiotics have not yet been broadly described in reservoirs outside of the aforementioned environments, nor is the transfer and dissemination of antibiotic resistant bacteria and genes within natural microbial communities fully understood. This review will thus focus on low antibiotic-concentration environmental reservoirs and mechanisms that are important in the dissemination of antibiotic resistance to help identify key knowledge gaps concerning the environmental resistome.

Piglet Gut and in-Barn Manure from Farms on a Raised without Antibiotics Program Display Reduced Antimicrobial Resistance but an Increased Prevalence of Pathogens.

In response to new stringent regulations in Canada regarding the use of antibiotics in animal production, many farms have implemented practices to produce animals that are raised without antibiotics (RWA) from birth to slaughter. This study aims to assess the impact of RWA production practices on reducing the actual total on-farm use of antibiotics, the occurrence of pathogens, and the prevalence of antimicrobial resistance (AMR). A 28-month longitudinal surveillance of farms that adopted the RWA program and conventional farms using antibiotics in accordance with the new regulations (non-RWA) was conducted by collecting fecal samples from 6-week-old pigs and composite manure from the barn over six time points and applying whole-genome sequencing (WGS) to assess the prevalence of AMR genes as well as the abundance of pathogens. Analysis of in-barn drug use records confirmed the decreased consumption of antibiotics in RWA barns compared to non-RWA barns. WGS analyses revealed that RWA barns had reduced the frequency of AMR genes in piglet feces and in-barn manure. However, metagenomic analyses showed that RWA barns had a significant increase in the frequency of pathogenic Firmicutes in fecal samples and pathogenic Proteobacteria in barn manure samples.

Prediction of bacterial functional diversity in clay microcosms.

Microorganisms in clay barriers could affect the long-term performance of waste containers in future deep geological repositories (DGR) for used nuclear fuel through production of corrosive metabolites (e.g., sulfide), which is why clay materials are highly compacted: to reduce both physical space and access to water for microorganisms to grow. However, the highly compacted nature of clays and the resulting low activity or dormancy of microorganisms complicate the extraction of biomarkers (i.e., PLFA, DNA etc.) from such barriers for predictive analysis of microbial risks. In order to overcome these challenges, we have combined culture- and 16S rRNA gene amplicon sequencing-based approaches to describe the functional diversity of microorganisms in several commercial clay products, including two different samples of Wyoming type MX-80 bentonite (Batch 1 and Batch 2), the reference clay for a future Canadian DGR, and Avonlea type Canaprill, a clay sample for comparison. Microorganisms from as-received bentonites were enriched in anoxic 10% w/v clay microcosms for three months at ambient temperature with addition of 10% hydrogen along with presumable indigenous organics and sulfate in the clay. High-throughput sequencing of 16S rRNA gene fragments indicated a high abundance of Gram-positive bacteria of the phylum Firmicutes (82%) in MX-80 Batch 1 incubations. Bacterial libraries from microcosms with MX-80 Batch 2 were enriched with Firmicutes (53%) and Chloroflexi (43%). Firmicutes also significantly contributed (<15%) to the bacterial community in Canaprill clay microcosm, which was dominated by Gram-negative Proteobacteria (>70%). Sequence analysis revealed presence of the bacterial families Peptostreptococcaceae, Clostridiaceae, Peptococcaceae, Bacillaceae, Enterobacteriaceae, Veillonellaceae, Tissierellaceae and Planococcaceae in MX-80 Batch 1 incubations; Bacillaceae, along with unidentified bacteria of the phylum Chloroflexi, in MX-80 Batch 2 clay microcosms, and Pseudomonadaceae, Hydrogenophilaceae, Bacillaceae, Desulfobacteraceae, Desulfobulbaceae, Peptococcaceae, Pelobacteraceae, Alcaligenaceae, Rhodospirillaceae in Canaprill microcosms. Exploration of potential metabolic pathways in the bacterial communities from the clay microcosms suggested variable patterns of sulfur cycling in the different clays with the possible prevalence of bacterial sulfate-reduction in MX-80 bentonite, and probably successive sulfate-reduction/sulfur-oxidation reactions in Canaprill microcosms. Furthermore, analysis of potential metabolic pathways in the bentonite enrichments suggested that bacteria with acid-producing capabilities (i.e., fermenters and acetogens) together with sulfide-producing prokaryotes might perhaps contribute to corrosion risks in clay systems. However, the low activity or dormancy of microorganisms in highly compacted bentonites as a result of severe environmental constraints (e.g., low water activity and high swelling pressure in the confined bentonite) in situ would be expected to largely inhibit bacterial activity in highly compacted clay-based barriers in a future DGR.

Antimicrobial Biodegradable Food Packaging Based on Chitosan and Metal/Metal-Oxide Bio-Nanocomposites: A Review.

Finding a practical alternative to decrease the use of conventional polymers in the plastic industry has become an acute concern since industrially-produced plastic waste, mainly conventional food packaging, has become an environmental crisis worldwide. Biodegradable polymers have attracted the attention of researchers as a possible alternative for fossil-based plastics. Chitosan-based packaging materials, in particular, have become a recent focus for the biodegradable food packaging sector due to their biodegradability, non-toxic nature, and antimicrobial properties. Chitosan, obtained from chitin, is the most abundant biopolymer in nature after cellulose. Chitosan is an ideal biomaterial for active packaging as it can be fabricated alone or combined with other polymers as well as metallic antimicrobial particles, either as layers or as coacervates for examination as functional components of active packaging systems. Chitosan-metal/metal oxide bio-nanocomposites have seen growing interest as antimicrobial packaging materials, with several different mechanisms of inhibition speculated to include direct physical interactions or chemical reactions (i.e., the production of reactive oxygen species as well as the increased dissolution of toxic metal cations). The use of chitosan and its metal/metal oxide (i.e., titanium dioxide, zinc oxide, and silver nanoparticles) bio-nanocomposites in packaging applications are the primary focus of discussion in this review.

Draft Genome Sequence of Arthrobacter sp. Strain 260, Isolated from a Uranium Tailings Management Facility in Northern Saskatchewan, Canada.

The 3.9-Mbp draft genome sequence of Arthrobacter sp. strain 260, which was isolated from a uranium tailings management facility, is reported. The sequence may help determine the bioremediation potential of this strain and facilitate further research aimed at a better understanding of the hypertolerance of this genus to extreme conditions.

Impact of sample collection on prokaryotic and eukaryotic diversity of niche environments of the oil-sand mining impacted Athabasca River.

Microbial communities are an important aspect of overall riverine ecology; however, appreciation of the effects of anthropogenic activities on unique riverine microbial niches, and how the collection of these samples affects the observed diversity and community profile is lacking. We analyzed prokaryotic and eukaryotic communities from surface water, biofilms, and suspended load niches along a gradient of oil sands-related contamination in the Athabasca River (Alberta, Canada), with suspended load or particle-associated communities collected either via Kenney Sampler or centrifugation manifold. At the phylum level, different niche communities were highly similar to each other and across locations. However, there were significant differences in the abundance of specific genera among the different niches and across sampling locations. A generalized linear model revealed that use of the Kenney Sampler resulted in more diverse bacterial and eukaryotic suspended load community than centrifugal collection, though suspended load communities collected by any means remained stably diverse across locations. Although there was an influence of water quality parameters on community composition, all sampled sites support diverse bacterial and eukaryotic communities regardless of the degree of contamination, highlighting the need to look beyond ecological diversity as a means of assessing ecological perturbations, and consider collecting samples from multiple niche environments.

A health metadata-based management approach for comparative analysis of high-throughput genetic sequences for quantifying antimicrobial resistance reduction in Canadian hog barns.

New Canadian regulations have required that all use of antibiotics in livestock animal production should be under veterinary prescription and oversight, while the prophylactic use and inclusion of these agents in animal feed as growth promoters are also banned. In response to this new rule, many Canadian animal producers have voluntarily implemented production practices aimed at producing animals effectively while avoiding the use of antibiotics. In the swine industry, one such program is the 'raised without antibiotics' (RWA) program. In this paper, we describe a comprehensive investigative methodology comparing the effect of the adoption of the RWA approach with non-RWA pig production operations where antibiotics may still be administered on animals as needed. Our experimental approach involves a multi-year longitudinal investigation of pig farming to determine the effects of antibiotic usage on the prevalence of antimicrobial resistance (AMR) and pathogen abundance in the context of the drug exposures recorded in the RWA versus non-RWA scenarios. Surveillance of AMR and pathogens was conducted using whole-genome sequencing (WGS) in conjunction with open source tools and data pipeline analyses, which inform on the resistome, virulome and bacterial diversity in animals and materials associated with the different types of barns. This information was combined and correlated with drug usage (types and amounts) over time, along with animal health metadata (stage of growth, reason for drug use, among others). The overarching goal was to develop a set of interconnected informatic tools and data management procedures wherein specific queries could be made and customized, to reveal statistically valid cause/effect relationships. Results demonstrating possible correlations between RWA and AMR would support the Canadian pig industry, as well as regulatory agencies in new efforts, focused on reducing overall antibiotics use and in curbing the development and spread of AMR related to animal agriculture.

Production of glycerol by Lactobacillus plantarum NRRL B-4496 and formation of hexamine during fermentation of pea protein enriched flour.

Suspensions of pea protein enriched flour (PP) inoculated with Lactobacillus plantarum NRRL B-4496 and uninoculated PP suspensions were incubated in vials covered with airtight caps. Organic compound compositions of fermented and unfermented PP suspensions (F-PP and U-PP, respectively) were analyzed using solid phase microextraction (SPME) coupled with gas chromatography - mass-spectrometry (GCMS). Acetic acid was detected in all samples; pH dropped from pH 6.5 to pH 4.1 in L. plantarum F-PP and to pH 5.3 in uninoculated F-PP. Abundance of acetic acid and minuscule presence of lactic acid in L. plantarum F-PP suggested that fermentation proceeded preferentially via the pyruvate formate lyase (PFL) pathway. Nonetheless, glycerol appeared to be the most abundant compound in L. plantarum F-PP samples; colorimetric analysis indicated that its average concentration in these samples was 1.05 g/L. A metabolic switch from the PFL pathway to glycerol production might occur due to acidity tolerance limitations of L. plantarum, glycerol production being associated with the release of phosphate, which can act as a buffer. Fermentation of PP by L. plantarum also led to formation of hexamine, which is a known food preservation agent. Presence of naturally formed hexamine and glycerol in food products may render using chemical additives needless.

Metatranscriptomic Insights Into the Response of River Biofilm Communities to Ionic and Nano-Zinc Oxide Exposures.

Manufactured Zn oxide nanoparticle (ZnO-NP) are extensively used world-wide in personal care and industrial products and are important contaminants of aquatic environments. To understand the overall impact of ZnO-NP contamination on aquatic ecosystems, investigation of their toxicity on aquatic biofilms is of particular consequence, given biofilms are known sinks for NP contaminants. In order to assess alterations in the functional activity of river microbial biofilm communities as a result of environmentally-relevant ZnO-NP exposure, biofilms were exposed to ionic zinc salt or ZnOPs that were uncoated (hydrophilic), coated with silane (hydrophobic) or stearic acid (lipophilic), at a total concentration of 188 µg l-1 Zn. ICP-MS analyses of biofilms indicated ZnO-NP concentrated in the biofilms, with hydrophilic, hydrophobic, and lipophilic treatments reaching 0.310, 0.250, and 0.220 µg Zn cm-2 of biofilm, respectively, while scanning transmission X-ray microspectroscopy (STXM) analyses of biofilms confirmed that Zn was extensively- and differentially-sorbed to biofilm material. Microbial community composition, based on taxonomic affiliation of mRNA sequences and enumeration of protozoa and micrometazoa, was not affected by these treatments, and the total transcriptional response of biofilms to all experimental exposures was not indicative of a global toxic-response, as cellular processes involved in general cell maintenance and housekeeping were abundantly transcribed. Transcripts related to major biological processes, including photosynthesis, energy metabolism, nitrogen metabolism, lipid metabolism, membrane transport, antibiotic resistance and xenobiotic degradation, were differentially expressed in Zn-exposures relative to controls. Notably, transcripts involved in nitrogen fixation and photosynthesis were decreased in abundance in response to Zn-exposure, while transcripts related to lipid degradation and motility-chemotaxis were increased, suggesting a potential role of Zn in biofilm dissolution. ZnO-NP and ionic Zn exposures elicited generally overlapping transcriptional responses, however hydrophilic and hydrophobic ZnO-NPs induced a more distinct effect than that of lipophilic ZnO-NPs, which had an effect similar to that of low ionic Zn exposure. While the physical coating of ZnO-NP may not induce specific toxicity observable at a community level, alteration of ecologically important processes of photosynthesis and nitrogen cycling are an important potential consequence of exposure to ionic Zn and Zn oxides.

Scientific Prospects for Cannabis-Microbiome Research to Ensure Quality and Safety of Products.

Cannabis legalization has occurred in several countries worldwide. Along with steadily growing research in Cannabis healthcare science, there is an increasing interest for scientific-based knowledge in plant microbiology and food science, with work connecting the plant microbiome and plant health to product quality across the value chain of cannabis. This review paper provides an overview of the state of knowledge and challenges in Cannabis science, and thereby identifies critical risk management and safety issues in order to capitalize on innovations while ensuring product quality control. It highlights scientific gap areas to steer future research, with an emphasis on plant-microbiome sciences committed to using cutting-edge technologies for more efficient Cannabis production and high-quality products intended for recreational, pharmaceutical, and medicinal use.

Microscale and molecular analyses of river biofilm communities treated with microgram levels of cerium oxide nanoparticles indicate limited but significant effects.

Cerium oxide (CeO2) nanoparticles are used as in-fuel catalysts and in manufacturing processes, creating a potential for release to aquatic environments. Exposures at 1 and 10 µg/L CeO2-nanoparticles were made to assess effects during the development of river biofilm communities. Scanning transmission x-ray microscopy (STXM) indicated extensive sorption of nanoparticles to the community and co-localization with lipid moieties. Following 8 weeks of development, polycarbonate coupons were removed from the reactors and used for molecular analyses, denaturing gradient gel electrophoresis analysis (DGGE-16S rRNA) and 16S rRNA amplicon sequencing. Microscopic imaging of the biofilm communities (bacterial, photosynthetic biomass, exopolymer composition, thickness, protozoan numbers), as well as carbon substrate utilization fingerprinting was performed. There was a trend toward reduced photosynthetic biomass, but no significant effects of CeO2 exposure were found on photosynthetic and bacterial biomass or biofilm thickness. Sole carbon source utilization analyses indicated increased utilization of 10 carbon sources in the carbohydrate, carboxylic acid and amino acids categories related to CeO2 exposures; however, predominantly, no significant effects (p < 0.05) were detected. Measures of microbial diversity, lectin binding affinities of exopolymeric substances and results of DGGE analyses, indicated significant changes to community composition (p < 0.05) with CeO2 exposure. Increased binding of the lectin Canavalia ensiformis was observed, consistent with changes in bacterial-associated polymers. Whereas, no significant changes were observed in binding to residues associated with algal and cyanobacterial exopolymers. 16S rRNA amplicon sequencing of community DNA indicated changes in diversity and shifts in community composition; however, these did not trend with increasing CeO2 exposure. Counting of protozoans in the biofilm communities indicated no significant effects on this trophic level. Thus, based on biomass and functional measures, CeO2 nanoparticles did not appear to have significant effects; however, there was evidence of selection pressure resulting in significant changes in microbial community composition.

Role of CpxR in Biofilm Development: Expression of Key Fimbrial, O-Antigen and Virulence Operons of Salmonella Enteritidis.

Salmonella Enteritidis is a non-typhoidal serovar of great public health significance worldwide. The RpoE sigma factor and CpxRA two-component system are the major regulators of the extracytoplasmic stress response. In this study, we found that the CpxR has highly significant, but opposite effects on the auto-aggregation and swarming motility of S. Enteritidis. Auto-aggregation was negatively affected in the ∆cpxR mutant, whereas the same mutant significantly out-performed its wild-type counterpart with respect to swarming motility, indicating that the CpxR plays a role in biofilm-associated phenotypes. Indeed, biofilm-related assays showed that the CpxR is of critical importance in biofilm development under both static (microtiter plate) and dynamic (flow cell) media flow conditions. In contrast, the RpoE sigma factor showed no significant role in biofilm development under dynamic conditions. Transcriptomic analysis revealed that the cpxR mutation negatively affected the constitutive expression of the operons critical for biosynthesis of O-antigen and adherence, but positively affected the expression of virulence genes critical for Salmonella-mediated endocytosis. Conversely, CpxR induced the expression of curli csgAB and fimbrial stdAC operons only during biofilm development and flagellar motAB and fliL operons exclusively during the planktonic phase, indicating a responsive biofilm-associated loop of the CpxR regulator.

N,N-Diethyl-m-Toluamide Exposure at an Environmentally Relevant Concentration Influences River Microbial Community Development.

Studies of the South Saskatchewan River confirmed that N,N-diethyl-m-toluamide (DEET) is ubiquitous at 10 to 20 ng/L, whereas in effluent-dominated Wascana Creek, levels of 100 to 450 ng/L were observed. Effects of DEET exposure were assessed in microbial communities using a wide variety of measures. Communities developed in rotating annular reactors with either 100 or 500 ng/L DEET, verified using gas chromatography-mass spectrometry analyses. Microscale analyses indicated that both DEET concentrations resulted in significant (p < 0.05) declines in photosynthetic biomass, whereas bacterial biomass was unaffected. There was no detectable effect of DEET on the levels of chlorophyll a. However, pigment analyses indicated substantial shifts in algal-cyanobacterial community structure, with reductions of green algae and some cyanobacterial groups at 500 ng/L DEET. Protozoan/micrometazoan grazers increased in communities exposed to 500 ng/L, but not 100 ng/L, DEET. Based on thymidine incorporation or utilization of carbon sources, DEET had no significant effects on metabolic activities. Fluorescent lectin-binding analyses showed significant (p < 0.05) changes in glycoconjugate composition at both DEET concentrations, consistent with altered community structure. Principal component cluster analyses of denaturing gradient gel electrophoresis indicated that DEET exposure at either concentration significantly changed the bacterial community (p < 0.05). Analyses based on 16S ribosomal RNA of community composition confirmed changes with DEET exposure, increasing detectable beta-proteobacteria, whereas actinobacteria and acidimicrobia became undetectable. Further, cyanobacteria in the subclass Oscillatoriophycideae were similarly not detected. Thus, DEET can alter microbial community structure and function, supporting the need for further evaluation of its effects in aquatic habitats. Environ Toxicol Chem 2019;38:2414-2425. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Effect of glycerol on the physicochemical properties of films based on legume protein concentrates: A comparative study.

The overall goal of this research was to examine the mechanical, water vapor barrier properties and opacity of films prepared using legume protein concentrates (faba bean, pea, lupin, lentil, and soy) as a function of glycerol concentration (50, 75, or 100% [wt/wt]-relative to the protein weight). Overall, tensile strength (TS) decreased with increasing glycerol concentration, whereas tensile elongation (TE) and water vapor permeability (WVP) increased with increasing glycerol concentration. Film opacity was independent of glycerol concentration. The effect of protein-type varied considerably depending on the functional property of the film being measured; TS was greatest with faba bean and lowest with lupin, whereas TE was highest for pea, and lowest for soy. Lentil protein films had considerably higher WVP, at the 100% glycerol concentration, as compared to the other protein concentrates. Findings from this study indicate that legume protein concentrates are capable of forming biodegradable, edible films. Overall, pea protein concentrate films showed the most promise for application in terms of strength, elongation, and moisture barrier properties.