Probiotic Effect of <Emphasis Type="Italic">Bacillus licheniformis fb11</Emphasis> on the Digestive Efficiency and Growth Performance in Juvenile <Emphasis Type="Italic">Chitala chitala</Emphasis> (Hamilton, 1822)

Five isocaloric (430 kcal 100 g^?1), isonitrogenous (40% CP) experimental diets were formulated with different concentrations of Bacillus licheniformis fb11 probionts (isolated from the gut of Chitala chitala) viz. Control (without probionts), 5 × 10⁴ CFU g^?1 (D₁), 5 × 10⁵ CFU g^?1 (D₂), 5 × 10⁶ CFU g^?1 (D₃), 5 × 10⁷ CFU g^?1 (D₄), 5 × 10⁸ CFU g^?1 (D₅) to evaluate its efficiency in C. chitala juvenile. The best growth performance, feed utilisation, specific α-amylase, total protease and lipase activity were observed with the diet D₃ (P < 0.05). The lowest Presumptive Pseudomonas Count, Motile Aeromonad Count, Total Coliform Count was observed for D₃ (P < 0.05) on 90th day of trial. Two uppermost values were achieved in case of crude protein for D₃ and D₂ (P > 0.05). The highest lipid content (12.12 ± 0.4 g 100 g^?1) was found for D₅ (P < 0.05). The highest gross energy (18.75 ± 0.21 MJ 100 g^?1) of carcass was recorded for D₃. Thus B. licheniformis fb11 at the concentration 5 × 10⁶ CFU g^?1 as probiotic supplement promoted growth, digestion in C. chitala juvenile significantly by modulating intestinal microflora.     

Colonization of sorghum and wheat by seed inoculation with <Emphasis Type="Italic">Gluconacetobacter diazotrophicus</Emphasis>

Colonization of sorghum and wheat after seed inoculation with Gluconacetobacter diazotrophicus strains PAL 5 and UAP 5541/pRGS561 (containing the marker gene gusA) was studied by colony counting and microscopic observation of plant tissues. Inoculum levels as low as 10² CFU per seed were enough for root colonization and further spreading in aerial tissues. Rhizoplane colonization was around 7 log CFU g^?1 (fresh weight). G. diazotrophicus was found inside sorghum and wheat roots with populations higher than 5 log CFU g^?1 (fresh weight). Stem colonization remained stable for 30 days post inoculation with endophyte concentrations from 4 to 5 log CFU g^?1 (fresh weight) (in both plants). Population in leaves decreased continuously being undetectable after 17 days post inoculation.     

Formulation of the biocontrol agent <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis> CPA-8 using different approaches: liquid,freeze-drying and fluid-bed spray-drying

The present work focuses on the assessment and comparison of three different formulation technologies and the effect of protectants on cell viability, storage stability and antagonistic activity of the biocontrol agent Bacillus amyloliquefaciens CPA-8. Cultures were concentrated with different protective substances such as MgSO₄, sucrose and skimmed milk (SM) and subjected to liquid formulation, freeze-drying and fluid-bed spray-drying. Results showed that CPA-8 freeze-dried cells without protectants or amended with SM suffered the highest losses in cell viability (0.41?0.48 log). Moreover, the cell viability of the tested freeze-dried products decreased after four months of storage at both tested temperatures (4 and 22 °C). Otherwise, liquid and fluid-bed spray-dried products were stable for four months at 4 °C and for 12 months at 22, 4 and ?20 °C, respectively, and no effect of the protectants was observed. The most suitable CPA-8 products were then tested against Monilinia laxa and M. fructicola in artificially wounded nectarines and in all cases the antagonistic activity was maintained similar to fresh cells. The efficacy results revealed that the formulation process did not affect the biocontrol potential of CPA-8. This work led us to conclude that effective formulations with final concentrations ranging from 1.93 × 10⁹–2.98 × 10⁹ CFU ml^?1 and from 4.76 × 10⁹–1.03 × 10¹⁰ CFU g^?1 were obtained for liquid and dried products, respectively. Additionally, the suitability of the fluid-bed spray drying technology should be taken into account to develop a stable and effective CPA-8 product for practical applications to control brown rot in stone fruit.     

Dietary Administration of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> Enhanced Growth Performance and Innate Immune Response of Siberian Sturgeon, <Emphasis Type="Italic">Acipenser baerii</Emphasis>

We investigated the effects of Lactobacillus plantarum used as a dietary supplement on the growth performance and innate immune response in juvenile Siberian sturgeon Acipenser baerii. Juvenile fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ colony-forming units (cfu) g^?1] and a control (non-supplemented basal) diet for 8 weeks. Growth performance indices were increased in fish fed the 1 × 10⁸ cfu g^?1 L. plantarum diet compared to the other groups. There was an increased innate immune response in fish fed the experimental diets. The highest levels of lysozyme activity, total immunoglobulin (IgM) and complement component 3 (C3) were observed in fish fed the diet containing L. plantarum at a concentration of 1 × 10⁸ cfu g^?1, but there was no significant difference in the level of complement component 4 (C4) in fish fed the experimental diets or the control diet. The present study underlying some positive effects (growth performance and immune indices) of dietary administration of L. plantarum at a concentration of 1 × 10⁸ cfu g^?1 in the Siberian sturgeon.     

Changes in Immunity,Expression of some Immune-Related Genes of Shabot Fish, <Emphasis Type="Italic">Tor grypus</Emphasis>, Following Experimental Infection with <Emphasis Type="Italic">Aeromonas hydrophila</Emphasis>: Effects of Autochthonous Probiotics

In this study, the effects of orally administrated two native probiotics (Lactobacillus plantarum and Lactobacillus delbrueckii ssp. bulguricus), isolated from the intestine of Shabot fish, Tor grypus, on some immune response parameters and immune-related genes expression against Aeromonas hydrophila in T. grypus were evaluated. Four hundred and eighty juveniles weighing 45?±?10 g were randomly divided into four groups (with three replications) and fed with the experimental diet containing 5?×?10⁷ cfu g^?1 of L. plantarum (G1), Lactobacillus bulgaricus (G2), Lactobacillus casei (G3), and a control diet (without probiotics) for 60 continuous days. At the end of the dietary treatments, fish were challenged with a lethal concentration of A. hydrophila (5?×?10⁸ CFU ml^?1) via intra peritoneal (i.p) injection. Blood and head kidney samples were taken from six fish in each treatment before challenging and 6, 12, 24, and 48 h and also 7 days after injection. The results showed that lysozyme, complement, bactericidal, and NBT activity of probiotic-treated groups were significantly elevated (P?<?0.05). The IL-8, IL-1β, and TNF-α gene expressions were significantly higher in all probiotic-treated groups (P?<?0.05). Meanwhile, a high direct correlation was observed between serum immune parameters and expression of immune-related genes (P?<?0.0001); furthermore, the highest correlation (R ²?=?0.634, P?<?0.0001) was recorded between IL-1β expression and NBT activity. It can be concluded that not only two native probiotics strains stimulate serum immune responses parameters and immune-related gene expression in T. grypus, but also a high correlation was seen among these indices. The study suggests that gastrointestinal colonization is preferred for host specificity as the strain previously derived from shabot fish displayed better colonization than the non-indigenous bacteria strain such as L. casei. Therefore, these native probiotics bacteria can be accounted as suitable candidates to immune stimulation in fish.     

Viability and Stress Response of Putative Probiotic <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> Strains in Honey Environment

Due to problem of preservation of dairy products which serve as a matrix for probiotics, it is challenging to use these probiotics as food supplements in many developing countries. To determine the suitability of the Lactobacillus strains for exploitation as probiotics in honey, we investigated the effect of their storage on the viability, functionality, and the mechanism associated with their protective effect. Three isolates obtained from our laboratory collection were identified through amplification of the 16S rRNA gene. The viability of the strains in honey at different storage conditions was studied. Three genes (hdc, gtf, and clpL) responsible for the resistance of bacteria in acidic environments were screened. SDS-PAGE analysis of total protein was performed to observe protein profile changes of the strains after exposure to honey. All the three isolates, namely, GGU, GLA51, and GLP56, were identified as Lactobacillus plantarum strains. After 28 days of storage in honey at 4 °C, viable cell concentrations of the three strains were higher than 2.04?×?10⁶ CFU/ml. During the same period at room temperature, only the Lactobacillus plantarum GLP56 strain remained viable with a cell concentration of 1.86?×?10⁴ CFU/ml. The clpL gene coding for ATPase was detected in all the three strains. The protein of molecular weight ~?50 kDa was absent in the protein profile of Lactobacillus plantarum GGU after 60 days of storage in honey at 4 °C. The Lactobacillus plantarum GLP56, Lactobacillus plantarum GLA51, and Lactobacillus plantarum GGU strains exposed to honey can withstand acidic environmental stress but their viability declines over time.     

Occurrence and distribution of multiple antibiotic-resistant <Emphasis Type="Italic">Enterococcus</Emphasis> and <Emphasis Type="Italic">Lactobacillus</Emphasis> spp. from Indian poultry: in vivo transferability of their erythromycin,tetracycline and vancomycin resistance

The objective of this study was to determine the occurrence and distribution of antibiotic resistant (AR) lactic acid bacteria (LAB) in Indian poultry. LAB from poultry farm feces (n = 21) and samples from slaughter houses comprising chicken intestine (n = 46), raw meat (n = 23), and sanitary water (n = 4) were evaluated and compared with those from organic chicken (OC) collected from nearby villages. Screening studies showed 5–7 log units higher erythromycin (ER), tetracycline (TC) and vancomycin (VAN) resistant LAB from conventional poultry chicken (CC) compared to OC. Molecular characterization of isolated cultures (n = 32) with repetitive-PCR profiling and 16S rRNA gene sequencing revealed their taxonomical status as Enterococcus faecium (n = 16), Enterococcus durans (n = 2), Lactobacillus plantarum (n = 10), Lactobacillus pentosus (n = 1) and Lactobacillus salivarius (n = 3). The isolates were found to harbor erm(B), msr(C), msr(A/B), tet(M), tet(L) and tet(K) genes associated with Tn916 and Tn917 family transposons. Expression studies through real-time PCR revealed antibiotic-induced expression of the identified AR genes. In vitro and in vivo conjugational studies revealed transfer of ER and TC resistant (ER^R and TC^R) genes with transfer frequencies of 10^?7 and 10^?4 transconjugants recipient^?1, respectively. Although no known VAN resistance (VAN^R) genes were detected, high phenotypic resistance was observed and was transferable to the recipient. From a public health point of view, this study reports Indian poultry as a major source of high levels of AR bacteria contaminating the food chain and the environment. Thus, urgent and determined strategies are needed to control the spread of multiple AR bacteria.     

Comparison of dichloran rose bengal chloramphenicol and Sabouraud dextrose agar with cycloheximide and chloramphenicol for airborne mold sampling

The more the mold species isolated on a culture medium, the more the sampling environment is represented accurately. According to the sampling purpose, it is crucial to use the best culture medium for mold. However, no study is available regarding the comparison of dichloran rose bengal chloramphenicol (DRBC) and Sabouraud dextrose agar with cycloheximide and chloramphenicol (SDA-CHX-CHL) culture media in terms of their application for airborne sampling, isolation, and identification of fungi. Airborne mold samples were impacted onto both DRBC and SDA-CHX-CHL, simultaneously using single-stage Andersen sampler. The limit of detection (LOD) value for airborne mold count was 7 CFU m^?3 (1 colony growth on the Petri dish). The total mold counts (TMC) ranged between <7 and 504 CFU m^?3 (med 56 CFU m^?3) and <7 and 1218 CFU m^?3 (med 259 CFU m^?3), collected on SDA-CHX-CHL and DRBC, respectively. Significantly higher TMC were observed on DRBC than on SDA regardless of the sampling environment (i.e, indoor or outdoor) (p < 0.05). Among the most predominant mold genera, observation frequencies of Penicillium spp. and Aspergillus spp. on both culture media were found to be more than 70%. Observation frequencies of Cladosporium spp., Alternaria spp., and yeast were found to be higher in samples collected on DRBC than those on SDA-CHX-CHL. Finally, DRBC was found to be superior to SDA in terms of both number of colonies and number of genera isolated from the air.     

Precise feeding of probiotics in the treatment of edwardsiellosis by accurate estimation of <Emphasis Type="Italic">Edwardsiella tarda</Emphasis>

Edwardsiella tarda is one of the leading fish pathogens for the aquaculture industry. To realize efficient disease control of edwardsiellosis, a predictive model for E. tarda in seawater was developed. The modified logistic model was used to regress the growth curves of E. tarda JN at five different temperatures (range from 10 to 30 °C) and four organic nutrient concentrations (range from 5 to 40 mg l^?1 measured by chemical oxygen demand (COD)). The modeling effects of temperature and COD on the specific growth rate (μ) were developed by square-root model and saturation-growth rate model, respectively. The growth model was validated in turbot aquaculture tanks by estimating the dynamics of inoculated E. tarda. The accurate feeding of probiotic Bacillus pumilus strain H2 was calculated based on the estimation of E. tarda. Results showed that the logistic model produced a good fit to the growth curves of E. tarda JN (average R²?=?0.962). The overall predictions based on above models agreed well with the growth curve of E. tarda JN observed by plate counting in the validation tests (average Af?=?1.16; average Bf?=?1.32). The use of predicted amount of B. pumilus (5.66 log CFU ml^?1) successfully prevent the deterioration of disease for turbot with 13.3% mortality rate in a recirculating aquaculture system (RAS), while the feeding of 0 and 3.0 log CFU ml^?1 of B. pumilus resulted in 53.7 and 75.3% of turbot mortality rate, respectively. In conclusion, accurate estimation of E. tarda realized the precise feeding of probiotics, which successfully prevent the rapid progression of the edwardsiellosis.     

Screening and molecular identification of potential probiotic lactic acid bacteria in effluents generated during ogi production

Screening and molecular identification of probiotic lactic acid bacteria (LAB) in effluents generated during the production of ogi, a fermented cereal (maize, millet, and sorghum) were done. LAB were isolated from effluents generated during the first and second fermentation stages in ogi production. Bacterial strains isolated were identified microscopically and phenotypically using standard methods. Probiotic potential properties of the isolated LAB were investigated in terms of their resistance to pH 1.5 and 0.3% bile salt concentration for 4 h. The potential LAB isolates ability to inhibit the growth of pathogenic organisms (Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium) was evaluated in vitro. The pH and LAB count in the effluents ranged from 3.31 to 4.49 and 3.67 to 4.72 log cfu/ml, respectively. A total of 88 LAB isolates were obtained from the effluents and only 10 LAB isolates remained viable at pH 1.5 and 0.3% bile salt. The zones of inhibition of the LAB isolates with probiotic potential ranged from 7.00 to 24.70 mm against test organsisms. Probiotic potential LAB isolates were molecularly identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus reuteri, Enterococcus faecium, Pediococcus acidilactici, Pediococcus pentosaceus, Enterococcus faecalis, and Lactobacillus brevis. Survival and proliferation of LAB isolates at low pH, 0.3% bile salt condition, and their inhibition against some test pathogens showed that these LAB isolates could be a potential probiotics for research and commercial purposes.     

Hemato-Immunological Responses and Disease Resistance in Siberian Sturgeon <Emphasis Type="Italic">Acipenser baerii</Emphasis> Fed on a Supplemented Diet of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis>

A feeding trial was conducted to investigate the effects of different levels of dietary Lactobacillus plantarum on hemato-immunological parameters and resistance against Streptococcus iniae infection in juvenile Siberian sturgeon Acipenser baerii. Fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ colony-forming units (cfu) g^?1] and a control (non-supplemented basal) diet for 8 weeks. Innate immune responses (immunoglobulin (Ig), alternative complement activity (ACH50) and lysozyme activity) were significantly higher in fish fed the 1 × 10⁸ and 1 × 10⁹ cfu g^?1 L. plantarum diet compared to the other groups (P < 0.05). Furthermore, fish fed on various levels of L. plantarum significantly showed higher red blood cell (RBC), hemoglobin (Hb), white blood cell (WBC) and monocyte compared to those of the control group (P < 0.05). At the end of the feeding experiment, some fish were challenged with S. iniae to quantify the level of disease resistance. The mortality after S. iniae challenge was decreased in fish fed a probiotic. These results indicated that dietary supplementation of L. plantarum improved immune response and disease resistance of Siberian sturgeon juvenile.     

Promotion of shoot regeneration of <Emphasis Type="Italic">Swertia chirata</Emphasis> by biosynthesized silver nanoparticles and their involvement in ethylene interceptions and activation of antioxidant activity

A complete protocol for the in vitro induction of Eclipta alba tetraploids has been optimized to enhance the wedelolactone content, an anti-cancerous compound. The effects of different concentrations of colchicine (0, 0.01, 0.05, 0.1, 0.2 and 0.3%; w/v) along with treatment durations (12, 24, 36 and 48 h) were investigated on shoot tip (ST) and nodal segment (NS). The treated explants were then incubated on Murashige and Skoog (MS) medium having 1.5 mg L^?1 N⁶-benzylaminopurine and 0.5 mg L^?1 α-napthalene acetic acid for shoot regeneration and afterward root was induced on 1.0 mg L^?1 indole-3-acetic acid enriched ½MS medium. The tetraploids of E. alba were proficiently induced by the treatment of 0.1% colchicine for 24 h. The highest tetraploid induction efficiency was obtained from ST (30.56%) in comparison to the NS (22.22%). Analysis by spectrophotometry and flow cytometry showed that colchicine treated plants contained higher quantity of DNA than diploid plants. Cytological studies demonstrated doubled the chromosome number in tetraploids (2n?=?4x?=?44) than diploids (2n?=?2x?=?22). The ploidy level enhancement lead to alteration of other traits, like increased plant height, stem diameter, leaf size, stomatal size and chlorophyll content. As determined through high performance thin-layer chromatography, the ultimate achievement of this technique is the higher accumulation of wedelolactone in tetraploid plants (300.32 µg g^?1 dry weight) in evaluation to in vitro diploid (131.31 µg g^?1 dry weight) and in vivo diploid mother plants (93.26 µg g^?1 dry weight), thus improving the pharmaceutical value of E. alba.     

Desiccation-induced ROS accumulation and lipid catabolism in recalcitrant <Emphasis Type="Italic">Madhuca latifolia</Emphasis> seeds

Loss of viability in desiccation-sensitive seeds of Madhuca latifolia (Roxb.) J. F. Macbr., an important multipurpose tropical tree, was correlated with seed water content (WC). WC declined from 0.59 to 0.19 g g^?1 fresh mass, 35 days after harvest from mother plant, at ambient conditions (temperature 25 ± 2 °C, relative humidity 50 ± 2%). The desiccation-induced reduction in viability was related with an accumulation of reactive oxygen species (ROS) that promoted lipid peroxidation associated loss of membrane integrity. Conducted study revealed 1.6–19 folds rise in lipid peroxidized products in desiccated M. latifolia seeds, and was found to be linked inversely with WC and germination percentage. Additionally, increased activities (7 and 13 folds) of lipid hydrolyzing enzymes; lipase (EC 3.1.1.3) and lipoxygenase (EC 1.13.11.12) respectively, were discernible in desiccating M. latifolia seeds. In summary, increased ROS, lipid oxidation, lipase and lipoxygenase were strongly correlated with viability loss in desiccating M. latifolia seeds.     

Immobilization of <Emphasis Type="Italic">Pseudomonas putida</Emphasis> PT in resistant matrices to environmental stresses: a strategy for continuous removal of heavy metals under extreme conditions

The purpose of this study was to investigate the potential of immobilized lead- and cadmium-resistant Pseudomonas putida strain PT to remove heavy metals from aqueous medium under extreme conditions. The tolerance and accumulation of cadmium and lead ions by strain PT were investigated by minimal inhibitory concentration (MIC) determination and polymerase chain reaction (PCR) of cadA gene, respectively. The surface chemical functional groups of P. putida PT involved in the metal biosorption were identified by Fourier transform infrared (FTIR). Pseudomonas putida PT was immobilized in three matrices include carboxy-methyl cellulose (CMC), rice bran, and a new composite made of alginate, polyvinyl alcohol (PVA), and CaCO₃ to prepare heavy metal adsorbent. The biosorbents were analyzed by SEM, and their metal removal capability was assayed in two consecutive cycles by atomic absorption spectroscopy. The viability of immobilized bacterial cells was determined by flow cytometry during storage at 4 °C and exposure to the environmental stresses (pH and temperature). The results showed that PT strain was resistant up to 10 mM Pb²⁺ and 8 mM Cd²⁺. FTIR analysis revealed that alcohol, sulfur, phosphate, esters, and amide groups played important roles in metal biosorption process and, also change in metabolic reactions like hydration and polyesters accumulation was observed after metal biosorption. The presence of cadA gene, a heavy metal translocating pump-coding gene, indicated the ability of metals bioaccumulation by the PT strain. Immobilized cells in alginate–PVA–CaCO₃ and rice bran showed the highest metal removal efficiency for Pb²⁺ as 75% and Cd²⁺ as 96.7%, respectively. Metal adsorbents were reusable, and the highest removal efficiency in the second cycle was observed in inoculated alginate–PVA–CaCO₃ (79.5% Pb²⁺ and 45% Cd²⁺). Flow cytometric analysis represented that the immobilized cell viability was retained (<?97%) after 4 weeks storage at 4 °C. Viability under two environmental stresses in all matrices was as follows: <?96% at 25 °C, <?87% at 45 °C, <?85% at pH 4,?<?96% at pH 7, and?<?89% at pH 11. The results signify that these metal adsorbents are efficient technological tools for bioremediation even in harsh environmental conditions.     

Cryopreservation of <Emphasis Type="Italic">Citrus</Emphasis> anthers in the National Crop Genebank of China

Genebank conservation of pollen is valuable because it makes genetic resources immediately available for use in breeding programs. In the case of Citrus species, conserved anthers or pollen can be easily transported and used to develop new varieties with pathogen resistance and desirable quality and yield traits. The aim of this study was to develop and improve air-desiccation cryopreservation protocols for Citrus cavaleriei and Citrus maxima anthers in genebanks. In the current study, warming, rehydration, and in vitro germination conditions were optimized to achieve high levels of in vitro germination in Citrus pollen for ten cultivars after liquid nitrogen (LN) exposure. The optimal warming, rehydration, and in vitro germination medium formulations affected the germination levels after pollen cryopreservation, with species- and cultivar-dependent effects. The Citrus anthers were dehydrated to the moisture content of 5–14% before LN exposure and warmed at 25 (cryopreserved Citrus anthers with a moisture content of lower than 10%) or 37°C (a moisture content of 10% or higher), then rehydrated, and cultured on medium with 150-g L^?1 sucrose, 0.1-g L^?1 boric acid, 1.0-g L^?1 calcium nitrate, 0.1-g L^?1 potassium nitrate, 0.3-g L^?1 magnesium sulfate, and 10-g L^?1 agar. After 2 yr of storage, in vitro germination levels of Citrus pollen after cryopreservation were significantly higher (> 22% for all ten cultivars) than those of samples that were stored at 4°C (0%). In vitro germination levels of pollen from six of ten cultivars after cryopreservation remained relatively high after 2 yr of storage (38–93%). The highest viability of 93% was obtained for C. cavaleriei ‘2–3’. The methods identified in the current study could be used to cryopreserve C. cavaleriei and C. maxima anthers.     

Abscisic Acid-Induced Starch Accumulation in Bioenergy Crop Duckweed <Emphasis Type="Italic">Spirodela polyrrhiza</Emphasis>

Spirodela polyrrhiza, a fast-growing duckweed with high starch and low lignin content, shows promise as a feedstock for bioenergy. Abscisic acid (ABA) is a biological hormone that controls plant growth and stress response. The effects of different ABA concentrations (0, 1.0 × 10^?5, 1.0 × 10^?4, 1.0 × 10^?3, 1.0 × 10^?2, and 1.0 × 10^?1 mg/L) on duckweed biomass growth, carbon dioxide fixation, formation of photosynthetic pigments (Chlorophyll a (Chla), Chlorophyll b (Chlb), and carotenoids), the activities of soluble starch synthase (SSS) and starch branching enzyme (SBE), and the starch content of biomass were investigated in this study. ABA at concentrations lower than 1.0 × 10^?3 mg/L promoted carbon dioxide fixation, whereas it inhibited carbon dioxide fixation at concentrations over 1.0 × 10^?3 mg/L. ABA enhanced SSS and SBE activities at concentrations lower than 1.0 × 10^?2 mg/L. ABA treatment increased the content of Chla, Chlb, and carotenoids and resulted in the enhancement of starch content. Chla content gradually increased with the increasing concentration of ABA (1.0 × 10^?5 to 1.0 × 10^?2 mg/L). After culturing for 10 days, starch content in 1.0 × 10^?2 mg/L ABA medium reached 35.3% of dry weight (DW), which was the highest level in this study. This suggests that there is a great potential to develop a technology to increase starch accumulation in duckweed which can be used as an alternative to corn, sugarcane, or other food crops as a starch source.     

Characterization of a new multifunctional beta-glucosidase from <Emphasis Type="Italic">Musca domestica</Emphasis>

Objective

To engineer Pichia pastoris for heterologous production of cellulase from Musca domestica and explore its potential for industrial applications.

Results

A new beta-glucosidase gene (bg), encoding 562 amino acids, was cloned from M. domestica by using rapid amplification of cDNA ends. The gene bg was linked to pPICZαA and expressed in P. pastoris with a yield of 500 mg l^?1. The enzyme has the maximum activity with 27.6 U mg^?1 towards cellulose. The beta-glucosidase has stable activity from 20 to 70 °C and can tolerate one-mole glucose. It has the maximum activities for salicin (25.9 ± 1.8 U mg^?1), cellobiose (40.1 ± 2.3 U mg^?1) and cellulose (27.6 ± 3.5 U mg^?1). The wide-range substrate activities of the beta-glucosidase were further verified by matrix-assisted laser desorption/ionization mass spectra. Structural analysis shows that the beta-glucosidase belongs to glycoside hydrolase family Ι and possesses O-glycosylation sites.

Conclusions

Thus, a multifunctional beta-glucosidase was expressed from M. domestica and provides a potential tool for industrial application of cellulose.

     

Inhibition of <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> in Hot Dogs by Surface Application of Freeze-Dried Bacteriocin-Containing Powders from Lactic Acid Bacteria

Six lactic acid bacteria (LAB) strains, Lactococcus lactis BFE 920, L. lactis subsp. lactis ATCC 11454, L. lactis subsp. cremoris ATCC 14365, Lactobacillus curvatus L442, Lact. curvatus LTH 1174, and Lact. bavaricus MN, were grown in cheddar cheese whey supplemented with complex nutrient sources. Cell-free culture supernatants were freeze-dried, and the resulting bacteriocin-containing powders were applied on the surface of hot dogs that were inoculated (~4 log cfu/hot dog) with a five-strain Listeria monocytogenes cocktail. Hot dogs were vacuum-sealed and stored at 4 °C for 4 weeks. L. monocytogenes was enumerated, using both tryptic soy agar (TSA) and oxford listeria agar (OXA), on day 0 and at 1, 2, 3, and 4 weeks of the refrigerated storage. In hot dogs containing only the L. monocytogenes inoculum, L. monocytogenes counts increased from 4 up to 7 log cfu/hot dog. All samples containing freeze-dried bacteriocin-containing powders exhibited significantly lowered (P < 0.05) L. monocytogenes populations on the surface of hot dogs throughout the 4-week study except for bavaricin MN powder. Bacterial counts on hot dogs packed without any powder were statistically equal on day 0 when enumerated on OXA. Freeze-dried bacteriocin-containing powders from Lact. curvatus L442 and L. lactis subsp. cremoris ATCC 14365 decreased L. monocytogenes populations on the surface of hot dogs by greater than 2 log cfu/hot dog throughout the 4-week study. For the powdered bacteriocin preparations from L. lactis BFE 920, L. lactis subsp. lactis ATCC 11454, and Lact. curvatus LTH 1174, L. monocytogenes populations were determined to be approximately 3-log cfu/hot dog after 4 weeks of storage.     

Simultaneous production of intracellular triacylglycerols and extracellular polyol esters of fatty acids by <Emphasis Type="Italic">Rhodotorula babjevae</Emphasis> and <Emphasis Type="Italic">Rhodotorula</Emphasis> aff. <Emphasis Type="Italic">paludigena</Emphasis>

Microbial oils have been analyzed as alternatives to petroleum. However, just a handful of microbes have been successfully adapted to produce chemicals that can compete with their petroleum counterparts. One of the reasons behind the low success rate is the overall economic inefficiency of valorizing a single product. This study presents a lab-scale analysis of two yeast species that simultaneously produce multiple high-value bioproducts: intracellular triacylglycerols (TG) and extracellular polyol esters of fatty acids (PEFA), two lipid classes with immediate applications in the biofuels and surfactant industries. At harvest, the yeast strain Rhodotorula aff. paludigena UCDFST 81-84 secreted 20.9 ± 0.2 g L^?1 PEFA and produced 8.8 ± 1.0 g L^?1 TG, while the yeast strain Rhodotorula babjevae UCDFST 04-877 secreted 11.2 ± 1.6 g L^?1 PEFA and 18.5 ± 1.7 g L^?1 TG. The overall glucose conversion was 0.24 and 0.22 g_{(total lipid)} g _(glucose) ^?1 , respectively. The results present a stable and scalable microbial growth platform yielding multiple co-products.     

Effect of Temperature on Development and Reproduction of <Emphasis Type="Italic">Epilachna dodecastigma</Emphasis> (Wied.) (Coleoptera: Coccinellidae)

The effect of five constant temperatures of 21, 24, 27, 30 and 33 °C on adult life span, reproduction, oviposition behavior and larval developmental time of a bitter gourd inhabited coleopteran insect Epilachna dodecastigma (Wied.) (Coccinellidae) was determined in laboratory conditions under 70 ± 5 % relative humidity and a photoperiod of 12 L : 12 D. Larval developmental time of E. dodecastigma decreased as temperature increased from 21 to 33 °C. Life table data revealed that overall mortality was lowest at 27 °C and highest at 21 °C. Females lived longer than males at all temperatures; but longevity decreased with increase in temperature. Pre-oviposition period decreased significantly with increase in temperature up to 27 °C and thereafter increased at a slower rate; whereas oviposition period decreased significantly with increase in temperature. Fecundity and egg viability increased significantly with an increase in temperature up to 27 °C and thereafter decreased at a slower rate. The intrinsic rate of increase (r _m ) was 0.1703, 0.1984, 0.2235, 0.2227 and 0.2181 day^?1 at 21, 24, 27, 30 and 33 °C, respectively. The net reproductive rate and finite rate of increase was highest at 27 °C (R _o  = 112.05; λ = 1.4233) and lowest at 21 °C (R _o  = 51.23; λ = 1.2581).