Inactivated Yeast Research Articles

Removal of Alternaria mycotoxins from aqueous solution by inactivated yeast powder.

Alternariol (AOH) and alternariol monomethyl ether (AME), produced by Alternaria spp., are the two mycotoxins with the highest outbreak rates in food systems. The purpose of this study was to investigate the removal of AOH and AME from aqueous solutions by inactivated yeast cells. The effects of strains, yeast powder amount, temperature, and pH were evaluated. The kinetics of AOH and AME adsorption on inactivated yeast cells was fitted with four models and a release assay was carried out. All three tested yeasts could remove AOH and AME. GIM 2.119 was the most effective strain. The reduction rate of both AOH and AME could be as much as 100% with 40 g‧L-1 of yeast powder. For both mycotoxins, pH = 9 was the best environment for toxin removal. The pseudo-second-order kinetic model was the best model, with R2 ranging from 0.989 to 0.999. However, the R2 of the pseudo-first-order and Elovich models was also relatively high. Alternariol and AME could be partially eluted by methanol and acetonitrile. The inactivated yeast cells could effectively remove AOH and AME. This was best fitted by the pseudo-second-order model. The release assay suggested that the adsorption of Alternaria mycotoxins was partially reversible. The results of this study provide a theoretical basis for the removal of Alternaria mycotoxins from food systems and are useful for the investigation of the mechanisms involved in mycotoxin adsorption by inactivated yeast cells. © 2020 Society of Chemical Industry.

How Pre-Harvest Inactivated Yeast Treatment May Influence the Norisoprenoid Aroma Potential in Wine Grapes

Carotenoids are important secondary metabolites in wine grapes and play a key role as potential precursors of aroma compounds (i.e., C13-norisoprenoids), which have a high sensorial impact in wines. There is scarce information about the influence of pre-harvest inactivated yeast treatment on the norisoprenoid aroma potential of grapes. Thus, this work aimed to study the effect of the foliar application of yeast extracts (YE) to Negro Amaro and Primitivo grapevines on the carotenoid content during grape ripening and the difference between the resulting véraison and maturity (ΔC). The results showed that β-carotene and (allE)-lutein were the most abundant carotenoids in all samples, ranging from 60% to 70% of total compounds. Their levels, as well as those of violaxanthin, (9′Z)-neoxanthin, and 5,6-epoxylutein, decreased during ripening. This was especially observed in treated grapes, with ΔC values from 2.6 to 4.2-fold higher than in untreated grapes. Besides this, a principal components analysis (PCA) demonstrated that lutein, β-carotene, and violaxanthin and (9′Z)-neoxanthin derivatives principally characterized Negro Amaro and Primitivo, respectively. Thereby, the YE treatment has proved to be effective in improving the C13-norisoprenoid aroma potentiality of Negro Amaro and Primitivo, which are fundamental cultivars in the context of Italian wine production.

Cyberlindnera jadinii yeast as a protein source for broiler chickens: effects on growth performance and digestive function from hatching to 30 days of age

Europe is heavily dependent on imported feed protein sources such as soybean meal (SBM); thus, investigating local sustainable alternatives is crucial to increase self-sufficiency. This study evaluated the effects of the inactivated yeast Cyberlindnera jadinii grown on local lignocellulosic sugars on the growth performance and digestive function of Ross 308 broiler chickens. A total of 1,000 male chicks were allocated to 20 pens. There were 5 replicate pens with 50 birds each, from 1 to 30 D after hatch. The birds were offered one conventional wheat–oat–SBM–based control diet and 3 diets with increasing levels of C. jadinii replacing 10, 20, and 30% of dietary crude protein (CP), whereas SBM levels were gradually decreased. The feed intake and weight gain of the birds decreased linearly, and feed conversion ratio increased linearly (P < 0.01) with increasing dietary levels of C. jadinii. Nevertheless, growth performance and feed intake were similar between the birds fed with control diets and diets containing 10% CP from C. jadinii in the starter and grower periods. The apparent ileal digestibility (AID) of dry matter, crude fat, organic matter, and carbohydrates was higher in control diets than in diets with 30% C. jadinii CP (P < 0.05) and decreased (P < 0.01) with incremental levels of dietary C. jadinii. Regardless, the AID of CP, starch, ash, and phosphorus was unaffected. Ileal villus height on day 10 was maintained in birds fed with diets containing 30% C. jadinii CP compared with the birds fed with control diets but was lower for birds fed with diets containing 10 and 20% C. jadinii protein (P < 0.05). To conclude, up to 10% C. jadinii CP can replace SBM CP in broiler chicken diets, maintaining growth performance and digestive function, whereas higher levels of C. jadinii may decrease bird performance. Altogether, this suggests the potential of C. jadinii as a local-based protein source in broiler chicken diets, contributing to a more sustainable feed.

Characterization of an adulticidal and larvicidal interfering RNA pesticide that targets a conserved sequence in mosquito G protein-coupled dopamine 1 receptor genes

G protein-coupled receptors (GPCRs), key regulators of a variety of critical biological processes, are attractive targets for insecticide development. Given the importance of these receptors in many organisms, including humans, it is critical that novel pesticides directed against GPCRs are designed to be species-specific. Here, we present characterization of an interfering RNA pesticide (IRP) targeting the mosquito GPCR-encoding dopamine 1 receptor (dop1) genes. A small interfering RNA corresponding to dop1 was identified in a screen for IRPs that kill Aedes aegypti during both the adult and larval stages. The 25 bp sequence targeted by this IRP is conserved in the dop1 genes of multiple mosquito species, but not in non-target organisms, indicating that it could function as a biorational mosquito insecticide. Aedes aegypti adults treated through microinjection or attractive toxic sugar bait delivery of small interfering RNA corresponding to the target site exhibited severe neural and behavioral defects and high levels of adult mortality. Likewise, A. aegypti larval consumption of dried inactivated yeast tablets prepared from a Saccharomyces cerevisiae strain engineered to express short hairpin RNA corresponding to the dop1 target site resulted in severe neural defects and larval mortality. Aedes albopictus and Anopheles gambiae adult and larval mortality was also observed following treatment with dop1 IRPs, which were not toxic to non-target arthropods. The results of this investigation indicate that dop1 IRPs can be used for species-specific targeting of dop1 GPCRs and may represent a new biorational strategy for control of both adult and larval mosquitoes.

Regulation of oxidative-restorative processes in secondary fermentation of wine materials in sparkling wine technology

The expediency of using preparations of dry inactivated (cell walls) yeast - glutaroma, salcline, bioproject, elivite and activite in the technology of sparkling wines produced by classical and reservoir methods has been studied. Decreased activity of redox potential is found when using said preparations irrespective of method of secondary fermentation. The greatest effect is noted in the combined use of cell wall preparations and bentonite suspension. The use of glutaroma and elivite, as well as mixtures thereof with bentonite, provided the highest amount of antioxidant activity of sparkling wine in both secondary fermentation methods. During the secondary fermentation of the control sample, an increase in glutathione content was observed in the first 2 weeks, after which its concentration remained virtually unchanged for 90 days of observation. The introduction into circulation of glutaroma, activite, bioproject, salcline, activated the fermentation process, and the concentration of reduced glutathione increased. A marked increase in glutathione concentration was found in the combined use of bentonite suspension with glutaroma, elivite and bioprotect. The increase in glutathione content was observed during the whole period of observation. On the basis of the obtained data, the mechanisms of oxidation-reduction process in production of sparkling wines by classical and reservoir methods are justified.

Thiol-functionalized inactivated yeast embedded in agar aerogel for highly efficient adsorption of patulin in apple juice

The issue of patulin (PAT) contamination in apple juice has attracted widespread concern. Recently, inactivated yeast based biosorbents have shown great advantages in the removal of toxic contaminants. However, the traditional yeast adsorbents have disadvantages of a limited adsorption capacity in juice and separation difficulty. In the present work, five chemical thiol-functionalization methods were used to increase the PAT adsorption efficiency of yeast cells in apple juice. Thereinto, glutaraldehyde cross-linking increased the thiol (-SH) content of yeast cells to 1.26 mmol g−1 and improved the PAT adsorption capacity of inactivated yeast in apple juice by 150 times. The covalent bonding of -SH and PAT played an important role in the improvement of adsorption capacity. The as-prepared thiol-modification yeast (Y-SH(Gl)) was then embedded in the agar aerogel to obtain Y-SH(Gl)@Agar free of separation. PAT adsorption of Y-SH(Gl)@Agar was consistent with the Freundlich model and the pseudo-second-order kinetic model. Moreover, Y-SH(Gl)@Agar was competent for PAT removal in apple juice and manifested negligible effects on juice quality. Cytotoxicity investigation indicated its good biocompatibility and ignorable food safety risk, thereby demonstrating that Y-SH(Gl)@Agar may be a promising adsorbent material for the control of PAT contaminant in juice.

Investigation of Active and Inactivated Yeast Cells by Scanning Electrochemical Impedance Microscopy

AbstractScanning electrochemical microscopy (SECM), electrochemical impedance spectroscopy (EIS) and scanning electrochemical impedance microscopy (SEIM) were used to investigate electrochemical activity of active and inactivated yeast Saccharomyces cerevisiae cells. SEIM experiment was performed using a unique electrochemical impedance spectrometer with a fast Fourier transform (FFT‐EIS) function, which enabled simultaneously perturb/evaluate electrochemical system at 50 frequencies. This allowed very quick observing the differences between impedance spectra, which were taken every few seconds. Therefore, we were able to apply SEIM for relatively fast determination of electrochemical impedance dependence on the distance between ultramicroelectrode (UME) and surface modified by immobilized yeast cells. It was determined that electrochemical activity and ‘breathing’ (a consumption of dissolved oxygen) of yeast can be electrochemically observed when the distance between UME and surface of yeast cells is in the range from 0 μm to 25 μm. Therefore, 25 μm is the maximum distance suitable for efficient investigation of yeast cell activity when experiments are performed in FFT‐SEIM mode. Charge transfer resistance of active and inactivated yeast cells was determined using EIS. It was calculated that charge transfer resistance of active yeast cells is 1.5 times lower than that of inactivated yeast cells. Lipophilic vitamin K3 (Vit‐K3) and hydrophilic vitamin K1 (Vit‐K1) were mixtured and used as redox mediators for charge transfer from yeast cells.

Growth performance and hemobiochemical parameters in South African dusky kob (Argyrosomus japonicus, Sciaenidae) offered brewer's yeast (Saccharomyces cerevisiae) as a feed additive

AbstractThere is some evidence that single‐cell proteins such as yeast have the potential to improve feed utilization in aquaculture fish, but this has not been investigated in the economically important dusky kob, Argyrosomus japonicus. This study was, therefore, designed to determine the effect of graded levels of dietary inactivated brewer's yeast, Saccharomyces cerevisiae, on the growth performance and hemobiochemical parameters of dusky kob in a 6‐week feeding period. Five isonitrogenous and isoenergetic diets—consisting of three brewer's yeast‐containing diets at rates of 50,150, and 300 g/kg dry matter (BY5P0, BY15P0, and BY30P0, respectively); a commercial dusky kob diet containing 10% probiotic mix but no brewer's yeast (BY0P1, positive control); and a commercial dusky kob diet with neither the probiotic mix nor the yeast (BY0P0, negative control)—were formulated. A total of 65 fish, weighing an average of 7.02 ± 0.10 g, were randomly distributed to each of 20 replicate tanks. Each dietary treatment was randomly allocated to four tanks and offered to fish at a rate of 2.8% fish body weight per day. A total of 10 fish from each tank were randomly sampled once a week for length and weight measurements. Blood was drawn from five fish per tank (20 fish per treatment) for hematology and serum biochemical analyses at the end of the 6 weeks. Fish on the BY0P0 diet achieved the highest weight gain of 18.53 ± 0.69 g after 6 weeks. Growth rate was significantly reduced in the groups fed BY15P0 and BY30P0 diets compared to the BY0P0, BY0P1, and BY5P0 groups. Fish fed the BY0P0 diet recorded the highest average feed conversion efficiency (FCE) of 0.22, while the BY30P0‐fed group recorded the lowest FCE of 0.15. Hematocrit and alanine transaminase levels declined with increasing levels of yeast. It can be concluded that the maximum inclusion level of brewer's yeast that does not impair growth performance and health of dusky kob is 50 g/kg.

Metabolic diversity conveyed by the process leading to glutathione accumulation in inactivated dry yeast: A synthetic media study.

Glutathione-rich inactivated dry yeasts (GSH-IDY) are purported to accumulate glutathione intracellularly and then released into the must. Glutathione is beneficial for wine quality, but research has highlighted that GSH-IDYs have a synergic antioxidant effect similar to that of molecular GSH. Combination of negative mode ultra-high-resolution Fourrier-Transform Ion-Cyclotron-Resonance Mass Spectrometry ((-)FT-ICR-MS), ultra-high-performance liquid chromatography coupled to a Quadrupole-Time of Flight mass spectrometer (UHPLC-Q-ToF-MS) and HPLC/Diode Detector Array (DAD)-Fluorescence spectroscopy was applied to three inactivated dry yeasts soluble fractions, with increasing intracellular glutathione concentration, in order to explore the chemical diversity released in different synthetic media. Using the mean of size exclusion chromatography/DAD and fluorescence detection we report than most of the signals detected were below the 5-75 kDa-calibrated region of the chromatogram, indicating that most of the soluble protein fraction is composed of low molecular weight soluble peptides. In light of these results, high-resolution mass spectrometry was used to scan and annotate the low molecular weight compounds from 50 to 1500 Da and showed that GSH level of enrichment in IDYs was correlated to a discriminant chemical diversity of the corresponding soluble fractions. Our results clearly show an impact of the GSH accumulation process not only visible on the glutathione itself, but also on the global diversity of compounds. Within the 1674 ions detected by (-)FT-ICR-MS, the ratio of annotated elemental formulas containing carbon, hydrogen, oxygen, nitrogen and sulfur (CHONS) to annotated elemental formulas containing carbon, hydrogen, oxygen (CHO) increased from 0.2 to 2.1 with the increasing levels of IDYs GSH content and 36 unique CHONS annotated formulas were unique to the IDY with the highest concentration of GSH. Amongst the 1674 detected ions 193 were annotated as potential peptides (from 2 to 5 residues), 61 ions were annotated as unique amino acid combinations and 46% of which being significantly more intense in GSH-rich IDY. Thus, the process leading to the accumulation of glutathione also involves other metabolic pathways which contribute to an increase in CHONS containing compounds potentially released in wine, notably peptides.

CBLB Constrains Inactivated Vaccine-Induced CD8+ T Cell Responses and Immunity against Lethal Fungal Pneumonia

Abstract Fungal infections in CD4+ T cell immunocompromised patients have risen sharply in recent years. Although vaccines offer a rational avenue to prevent infections, there are no licensed fungal vaccines available. Inactivated vaccines are safer but less efficacious and require adjuvants that may undesirably bias toward poor protective immune responses. We hypothesized that reducing the TCR signaling threshold could potentiate antifungal CD8+ T cell responses and immunity to inactivated vaccine in the absence of CD4+ T cells. In this study, we show that CBLB, a negative regulator of TCR signaling, suppresses CD8+ T cells in response to inactivated fungal vaccination in a mouse model of CD4+ T cell lymphopenia. Conversely, Cblb deficiency enhanced both the type 1 (e.g., IFN-γ) and type 17 (IL-17A) CD8+ T cell responses to inactivated fungal vaccines and augmented vaccine immunity to lethal fungal pneumonia. Furthermore, we show that immunization with live or inactivated vaccine yeast did not cause detectable pathologic condition in Cblb−/− mice. Augmented CD8+ T cell responses in the absence of CBLB also did not lead to terminal differentiation or adversely affect the expression of transcription factors T-bet, Eomes, and RORγt. Additionally, our adoptive transfer experiments showed that CBLB impedes the effector CD8+ T cell responses in a cell-intrinsic manner. Finally, we showed that ablation of Cblb overcomes the requirement of HIF-1α for expansion of CD8+ T cells upon vaccination. Thus, adjuvants that target CBLB may augment inactivated vaccines and immunity against systemic fungal infections in vulnerable patients.

Influence of supplementation with two specific inactivated dry yeast and grape-skin extract on the color and composition of red wine

Wines from grapes of Cabernet Sauvignon of the AOC Tarragona were elaborated with supplementation or not of two specific inactivated dry yeasts (Optired®and Optimum Red®; Lallemand Inc.) or with an experimental grape-skin extract. All the wines treated were significantly less astringent than the control wine because both inactivated dry yeast and the skin extract released polysaccharides which probably inhibit interactions between salivary proteins and tannins, and because their presence decrease the proportion of seed tannins and increase the proportion of skin tannins in the final wines.

Evaluation of inactivated yeast product to obtain quality grapes of Nanasaheb Purple Seedless

Grape growing under tropical conditions of India faces several biotic and abiotic challenges. Peculiar grape growing system where bunches face high temperature during maturity and ripening create hurdles in uniform colour development in coloured grapes. For even colour development, application of growth regulators especially ethephon, is adopted practice, but it reduces fruit firmness and increases berry shattering during the subsequent postharvest period. A formulation based on inactivated yeast (Saccharomyces cerevisiae) known as Lal-Vigne Mature (LVM) was applied for colour development on nanasaheb Purple Seedless during 2017 and 2018 to compare with ethrel, ethrel combined with LVM and control. Berries from control were recorded with higher TSS, lower acidity and higher pH in comparison to other treatments during both the years. Colour contributing compounds especially anthocyanins were minimum in berry skin of control. Thick skinned berries were obtained from treated than control. Physical loss in weight (PLW) values were higher in control during storage at ambient conditions compared to other treatments. Treatment with LVM (T2) was found effective in extended shelf life of grapes. On the basis of data obtained from present study it is observed that the application of LVM is found better for even colour development and longer shelf life of nanasaheb Purple Seedless.

Biochemical and molecular effects of yeast extract applications on anthocyanin accumulation in cv. Sangiovese.

The effect of biotic and abiotic elicitors on the secondary metabolism in grapevine is gaining a lot of interest, as it has been shown that they can increase the accumulation of phenolic compounds and anthocyanins in particular. The aim of this research was to verify the biochemical and molecular effects of the application of LalVigne™ MATURE (Lallemand, St. Simon, France), 100% inactivated natural yeast (Saccharomyces cerevisiae) on the anthocyanin accumulation in potted plants of Sangiovese. In both years, LVM plants did not differ from C in technological ripening at harvest. A significant increase in anthocyanin concentration and the expression of genes involved in their biosynthesis was found in 2016 in LVM grapes compared to C, while in 2017, a year with extremely warm temperatures, the anthocyanins of C and LVM were comparable, despite a slight increase in LVM after the second treatment.

Влияние низших грибов на биосинтез такролимуса (FK-506) штаммом Streptomyces tsukubensis BKM Ас-2618Д

The effect of inactivated yeast cells, cell components of yeast cells, and inactivated biomass of the lower fungi of various taxonomic positions on the immunosuppressant tacrolimus (FK-506) biosynthesis by Streptomyces tsukubensis VKM Ac-2618D has been studied. The fractions of soluble and insoluble components of yeast cells positively influenced the tacrolimus biosynthesis with its concentrations reaching 447.1±22.4 mg/L and 514.3±25.7 mg/L, respectively. Wherein, the insoluble cell components including cell walls and cytoplasmic membranes had a greater effect. The presence of the baker's yeast whole cells and filamentous fungus Aspergillus ochraceus biomass in the complex nutrient medium stimulated the tacrolimus production by S. tsukubensis VKM Ac-2618D (667.5±33.4 mg/L and 633.5±31.7 mg/L, respectively). The biomass of deuteromycete Curvularia lunata had no effect on the FK-506 biosynthesis (288.4±14.4 mg/L). Conversely, the biomass of fungus Gongronella butleri fully inhibited the growth and tacrolimus production by S. tsukubensis. The increase in the FK-506 production in media containing cells of the lower fungi is mainly related to the polysaccharide composition of their cell walls rather than the ergosterol content. The results extend the knowledge on the S. tsukubensis physiology and could be useful for the development of the tacrolimus biotechnological production. tacrolimus, biosynthesis, Streptomyces tsukubensis, yeasts, fungi, ergosterol The study was supported by the FASIE program UMNIK 16-12 (Project no. 12081GU/2017).

Different application dosages of a specific inactivated dry yeast (SIDY): effect on the polysaccharides, phenolic and volatile contents and color of Sauvignon blanc wines

Aim: The aims of this study were to (i) study the effect of different application dosages of a commercial specific inactivated dry yeast (SIDY) on several compounds (polysaccharides, phenolic and volatile compounds) and attributes (color parameters) related to the quality of white wines, and (ii) acquire better knowledge about the use of different dosages of SIDY in white wines with the objective to improve their quality.Methods and results: Three different dosages were applied (10, 20 and 40 g hL-1). Treated wines were followed after a contact time period of two months and after a bottle aging period of three months. Total phenolic content, color intensity, CIELab coordinates, polysaccharides, low molecular weight phenolic compounds and volatile compounds were evaluated.Conclusions: Higher dosages of this SIDY resulted in a greater release of polysaccharides into the wine. In parallel, a positive effect on the reduction or prevention of wine oxidation was observed due to the interaction with certain phenolic compounds. The application of the highest dosage seems to lead to an adsorption or retention effect of the major identified volatile compounds. This effect seems to be more evident after the contact time period than after the bottle storage period.Significance and impact of the study: This study can contribute to improve our knowledge on how applying different dosages of SIDY affects the physical and chemical quality of white wines.

CBLB Constrains Inactivated Vaccine–Induced CD8+ T Cell Responses and Immunity against Lethal Fungal Pneumonia

Fungal infections in CD4+ T cell immunocompromised patients have risen sharply in recent years. Although vaccines offer a rational avenue to prevent infections, there are no licensed fungal vaccines available. Inactivated vaccines are safer but less efficacious and require adjuvants that may undesirably bias toward poor protective immune responses. We hypothesized that reducing the TCR signaling threshold could potentiate antifungal CD8+ T cell responses and immunity to inactivated vaccine in the absence of CD4+ T cells. In this study, we show that CBLB, a negative regulator of TCR signaling, suppresses CD8+ T cells in response to inactivated fungal vaccination in a mouse model of CD4+ T cell lymphopenia. Conversely, Cblb deficiency enhanced both the type 1 (e.g., IFN-γ) and type 17 (IL-17A) CD8+ T cell responses to inactivated fungal vaccines and augmented vaccine immunity to lethal fungal pneumonia. Furthermore, we show that immunization with live or inactivated vaccine yeast did not cause detectable pathologic condition in Cblb-/- mice. Augmented CD8+ T cell responses in the absence of CBLB also did not lead to terminal differentiation or adversely affect the expression of transcription factors T-bet, Eomes, and RORγt. Additionally, our adoptive transfer experiments showed that CBLB impedes the effector CD8+ T cell responses in a cell-intrinsic manner. Finally, we showed that ablation of Cblb overcomes the requirement of HIF-1α for expansion of CD8+ T cells upon vaccination. Thus, adjuvants that target CBLB may augment inactivated vaccines and immunity against systemic fungal infections in vulnerable patients.

Effect of Yeast (saccharomyces cerevisiae) Supplementation on Haematological Parameters in Surti Buffalo Calves

The present study was conducted to evaluate the effect of dietary supplementation of yeast (Saccharomyces cerevisiae) on haematological parameter in 21 Surti young female buffalo calves (aged 6-12 months). They were divided equally into 3 groups (7 calves in each group) viz. Group I (control), II (supplementation of rumen specific yeast Saccharomyces cerevisiae CNCM I-1077 @ 4x109 cfu/animal/day) and III (supplementation of product of inactivated whole cell yeast Saccharomyces cerevisiae containing elevated levels of L (+) selenomethionine @ selenium inclusion rate in feed at 0.3 ppm). Whole blood was collected at day 0, 45 and 90 and haematological parameters were studied. Except in Group II which showed significant decrease in TEC, all haematological parameters were found within normal physiological range. Thus it was concluded that in female Surti buffalo calves supplementation of yeast and selenized yeast did not cause any significant change in haematological parameters.

Fate of anthocyanins in the presence of inactivated yeasts and yeast cell walls during simulation of wine aging

In the present research, two inactivated yeast strains (W13 and BM45) and a commercial yeast cell wall preparation (YCW) already tested for their ability to removal ochratoxin A were used to simulate the wine aging. During the simulated aging, the concentrations of the main 4 anthocyanins decreased in both the control wine and the wines added with yeasts, although at rates depending on the type of yeast and on the nature of anthocyanins. Peonidin-3-O-glucoside decreased by about 20% in the control wine and by ~ 50% in the wines added with yeast strains or the commercial yeast preparation. Malvidin-3-O-glucoside decreased by about 80% in the control wine and in the wine added with YCW and by about 96% in the wines added with W13 and BM45 strains. Cyanidin-3-O-glucoside decreased by 47% in the control wine, by 65-66% in the wines added with W13 and BM45 strains, and by 73% in the wine added with YCW. Delphinidin-3-O-glucoside decreased by 100% already after 21-28days of aging in all the wines.

Cellulase enhances endophytism of encapsulated Metarhizium brunneum in potato plants

The recent discovery that entomopathogenic fungi can grow endophytically in plant tissues has spurred research into novel plant protection measures. However, current applications of fungi aiming at endophytism mostly lack targeted formulation strategies resulting in low efficacy. Here, we aimed at enhancing Metarhizium brunneum CB15 endophytism in potato plants by (i) improvement of fungal growth from beads and (ii) cellulase formation or addition to encapsulated mycelium. We found that beads supplemented with cellulose alone or in addition with inactivated baker's yeast exhibited cellulase activity and increased mycelial growth by 12.6 % and 13.6 %, respectively. Higher enzymatic activity achieved by cellulase co-encapsulation promoted a shift from mycelial growth to spore formation with maximum numbers of 2.5 × 108 ± 6.1 × 107 per bead. This correlated with improved endophytism in potato plants by 61.2 % compared to non-supplemented beads. Our study provides first evidence that customized formulations of fungal entomopathogens with enzymes can improve endophytism and this may increase efficacy in plant protection strategies against herbivorous pests.

Yeast interfering RNA larvicides targeting neural genes induce high rates of Anopheles larval mortality

BackgroundAlthough larviciding can reduce the number of outdoor biting malaria vector mosquitoes, which may help to prevent residual malaria transmission, the current larvicide repertoire is faced with great challenges to sustainability. The identification of new effective, economical, and biorational larvicides could facilitate maintenance and expansion of the practice of larviciding in integrated malaria vector mosquito control programmes. Interfering RNA molecules represent a novel class of larvicides with untapped potential for sustainable mosquito control. This investigation tested the hypothesis that short interfering RNA molecules can be used as mosquito larvicides.ResultsA small interfering RNA (siRNA) screen for larval lethal genes identified siRNAs corresponding to the Anopheles gambiae suppressor of actin (Sac1), leukocyte receptor complex member (lrc), and offtrack (otk) genes. Saccharomyces cerevisiae (baker’s yeast) was engineered to produce short hairpin RNAs (shRNAs) for silencing of these genes. Feeding larvae with the engineered yeasts resulted in silenced target gene expression, a severe loss of neural synapses in the larval brain, and high levels of larval mortality. The larvicidal activities of yeast interfering RNA larvicides were retained following heat inactivation and drying of the yeast into user-friendly tablet formulations that induced up to 100% larval mortality in laboratory trials.ConclusionsReady-to-use dried inactivated yeast interfering RNA larvicide tablets may someday be an effective and inexpensive addition to malaria mosquito control programmes and a valuable, biorational tool for addressing residual malaria transmission.