Sucrose Medium Research Articles

A dual mechanism of cellulose deficiency in shv3svl1

ABSTRACTSHAVEN3 (SHV3) and its homolog SHAVEN3-like 1 (SVL1) encode glycosylphosphatidylinositol (GPI)-anchored proteins (GAPs) that are involved in cellulose biosynthesis and hypocotyl elongation in Arabidopsis thaliana. In a recent report, we showed that the cellulose and hypocotyl elongation defects of the shv3svl1 double mutant are greatly enhanced by exogenous sucrose in the growth medium. Further investigation of this phenomenon showed that shv3svl1 exhibits a hyperpolarized plasma membrane (PM) proton gradient that is coupled with enhanced accumulation of sucrose via the PM sucrose/proton symporter SUC1. The resulting high intracellular sucrose concentration appears to favor starch synthesis at the expense of cellulose synthesis. Here, we describe our interpretation of these results in terms of 2 potential regulators of cellulose synthesis: intracellular sucrose concentration and a putative signaling pathway that involves SHV3-like proteins.

Optimization of Seed Surface Sterilization Method and <i>in vitro</i> Seed Germination in <i>Althaea officinalis</i> (L.) - An Important Medicinal Herb

Objectives: The species Althaea officinalis is belong to Malvaceae family; its common name is Marshmallow. In this study an efficient technique has been optimized for sterilization of seed surface and also in vitro germination of seeds. Methods: Effect of different sterilizing agents with various concentrations and duration times as well as different media with various concentrations of sucrose on MGT (mean of germination time), GP (germination percentage), GR (germination rate), NDFG (number of days to first germination), CP (contamination percentage) and length of root and shoot of seedlings were recorded. For each experiment 25 seeds were treated and it was repeated at least three times. Findings: The maximum GP (80.0%) was recorded in sterilized-distilled water for 20 min (control), whereas minimum GP (44.0%) was recorded in experiment using 0.3% mercuric chloride (HgCl2) for 7 min. Between seed surface sterilization techniques used, maximum CP was achieved in control (85.33%) and minimum was found in 4% NaOCl (Sodium Hypochlorite), 10 min (13.33%), 0.3% HgCl2 for 7 min (14.66%) and 4% NaOCl for 5 min (17.33%). We compared the measured seed germination values (NDFG, MGT, GR, GP and CP) and among seed surface sterilization methods tested, NaOCl, 5 min has been found to be the best in A. officinalis. In addition, presence of sucrose in germination medium has shown negative effect on seed germination measured values as well seedling development. The effect of different surface sterilization techniques have no significant effect (p ≤ 0.05) on number of days to first germination (NDFG) but these techniques significantly affected (p ≤ 0.05) the other characteristics of seed sterilization. According to ANOVA results we report for the first time the best sterilization method and medium for in vitro seed germination and seedling development in A. officinalis.

Polyols, not sugars, determine the structural diversity of anti-streptococcal liamocins produced by Aureobasidium pullulans strain NRRL 50380.

Liamocins are polyol lipids produced by the fungus Aureobasidium pullulans, and have selective antibacterial activity against Streptococcus species. Liamocins produced by A. pullulans strain NRRL 50380 on sucrose medium have a d-mannitol head group ester-linked to 3,5-dihydroxydecanoate acyl chains, three or four of which are joined together by 1,5-polyester bonds (liamocins Man-A1 and Man-B1), and similar 3'-O-acetylated analogs (Man-A2 and Man-B2). However, other types of liamocins are produced depending on the choice of strain and growth conditions. In the current study, growth on different polyols, but not sugars, resulted in considerable structural variation, including liamocins with d-galactitol (dulcitol), d-sorbitol (glucitol), d- and l-arabitol, d-xylitol, l-threitol and glycerol head groups. The head groups of liamocins produced on arabitol were shown to be entirely composed of d-arabitol. These liamocin variants were structurally characterized by NMR and MS, and tested for antibacterial activity. The new liamocin variants also had selective activity against Streptococcus. Liamocin structural variants are novel antibacterials against Streptococcus sp. that merit further investigation.

Phenotypic homogeneity with minor deviance in osmotic fragility of Sahel goat erythrocytes in non-ionic sucrose media during various physiologic states.

Erythrocyte swelling in non-ionic sucrose media and the subsequent osmotic lysis are influenced by mechanisms of regulatory volume adjustment and osmotic water permeability. Kinetics of transmembrane water and ion fluxes in varied physiologic states may determine the phenotype of erythrocyte osmotic fragility (EOF) and affect estimates of EOF. Effects of sex, age, late pregnancy (third trimester) and lactation on the haemolysis of Sahel goat erythrocytes incubated in a series of hyposmotic non-ionic sucrose media were investigated. The fragiligram was sigmoidal in 72 (97%) out of 74 goats. Two male (3%) goats with low and high extreme median erythrocyte fragilities (MEF), had non-sigmoidal curves. The mean fragilities at osmolarities of 30-300 mosmol/L of sucrose and the mean osmolarities responsible for 10%-90% haemolysis (CH10-CH90) were not significantly different between males and non-pregnant dry (NPD) females, amongst the age groups and between pregnant or lactating and NPD female goats. The MEF (CH50) of the goats were at osmolarities of 126-252 mosmol/L (median of data: 171 mosmol/L) with a mean of 175.24±16.20 mosmol/L. Therefore, phenotypic homogeneity of EOF occurred with minor deviance, since EOF variables were not differentiated by sex, age, late pregnancy or lactation. Physiologic states of the goat did not affect EOF phenotype in non-ionic sucrose media. Sigmoidal fragility phenotype seemed to be homogeneously conserved by osmoregulatory mechanisms not partitioned by sex, age, late pregnancy or lactation, but a minor non-sigmoidal curve might have occurred due to altered erythrocyte osmotic behaviour that would require further investigation.

UJI VIABILITAS POLEN PADA DUA SPESIES BELIMBING HUTAN ( Averrhoa dolichocarpa dan A. leucopetala )

Wild starfruit Averrhoa dolichocarpa and A. leucopetala are new species reported. The aims of the research were to testing pollen viability at a day before anthesis (H -1 ) and at anthesis (H 0 ) stadia with germination in Brewbaker and Kwack (BK) and 10% sucrose media and staining test with 1% anilin blue and 1% I 2 KI. The optimum time for germination was 16 hours. Pollen viability in staining test results were higher than in germination test ie. 64.80% in BK medium, 54.60% in sukrosa, 88.60% in aniline blue dye and 88.50% in I 2 KI. BK medium showed a better result for germination test than 10% sucrose. In vitro viability germination test obtained the result that pollen viability value of wild starfruit at H 0 stadia was higher than pollen viability at H -1 stadia. While the result of staining test obtained that H -1 stadia was higher than at H 0 stadia. Long filament of Averrhoa dolichocarpa located on the slope had higher pollen viability than short filament. Filament factor in staining test was not significant. Pollen viability both in 10% sucrose to 1% aniline dye and 10% sucrose to 1% I 2 KI were negatively correlated. The correlation of pollen viability was not found either in BK medium and aniline dye blue or in BK medium and I 2 KI.

Impact of combined CO2 laser irradiation and fluoride on enamel and dentin biofilm-induced mineral loss.

The caries-protective effects of CO2 laser irradiation on dental enamel have been demonstrated using chemical demineralization models. We compared the effect of CO2 laser irradiation, sodium fluoride, or both on biofilm-induced mineral loss (∆Z) and Streptococcus mutans adhesion to enamel and dentin in vitro. Ground, polished bovine enamel, and dentin samples were allocated to four groups (n=12/group): no treatment (C); single 22,600-ppm fluoride (F) varnish (5% NaF) application; single CO2 laser treatment (L) with short pulses (5μs/λ=10.6μm); and laser and subsequent fluoride treatment (LF). Samples were sterilized and submitted to an automated mono-species S. mutans biofilm model. Brain heart infusion plus 5% sucrose medium was provided eight times daily, followed by rinses with artificial saliva. After 10days, bacterial numbers in biofilms were enumerated as colony-forming units/ml (CFU/ml) (n=7/group). ∆Z was assessed using transversal microradiography (n=12/group). Univariate ANOVA with post hoc Tukey honestly-significant-difference test was used for statistical analysis. Bacterial numbers were significantly higher on dentin than enamel (p<0.01/ANOVA). On dentin, LF yielded significantly lower CFUs than other groups (p=0.03/Tukey), while no differences between groups were found for enamel. The lowest ∆Z in enamel was observed for L (mean/SD 2036/1353vol%×μm), which was not only significantly lower than C (9642/2452vol%×μm) and F (7713/1489vol%×μm) (p<0.05) but also not significantly different from LF (3135/2628vol%×μm) (p>0.05). In dentin, only LF (163/227) significantly reduced ∆Z (p<0.05). CO2 laser irradiation did not increase adhesion of S. mutans in vitro. Laser treatment alone protected enamel against biofilm-induced demineralization, while a combined laser-fluoride application was required to protect dentin.

Regulation of in vitro morphogenesis in maize inbreds of the Lancaster group

The aim of this work is the comparative evaluation of the influence of physiologically active substances (PAS) on the ratio of morphogenesis types in vitro and plant regeneration in callus tissues of maize inbreds of the Lancaster heterotic group. Lancaster inbreds of Ukrainian selection DК267, DК6080 and DК298 and lines PLS61, A188 and Chi31 of foreign selection which represented eponymous heterotic groups were selected for into the research. For callusogenesis induction immature embryos of 1.0–1.5 mm in length were planted on a modified N6 medium with 30 g/l sucrose. For regeneration the 30-day callus tissue was transplanted to a modified MS medium containing 20 g/l sucrose and various PAS: 6-benzylaminopurine (BAP) (0.1 mg/l) or indolylbutyric acid (IBA) (1.0 mg/l), or cefotaxime (CT) (150 mg/l). Morphogenesis and plant regeneration were obtained in callus tissue by organogenesis through the formation of leaf-like structures or shoots only without roots (hemmogenesis) and by embryogenesis through the development of embryos with the cooperative laying of the apexes of the shoot and the root. The predominant type of in vitro morphogenesis in both groups of genotypes was organogenesis. A tendency to increasing the embryogenesis level among Lancaster inbreds in comparison with the other investigated groups was observed. A certain tendency to increase the level of embryogenesis on a medium for regeneration with IBA, compared to other PAS, was marked. So, for the Lancaster group the embryogenesis level on the medium with IBA was 33.3%, while for the other investigated genotypes it was about 10.3%. Regeneration frequency was 45.8 plantlets/100 calli for Lancaster inbred DК298, 42.2 plantlets/100 calli for DК267 and 5.6 plantlets/100 calli for DК6080. Regeneration frequency of inbred PLS61 was 204.0 plantlets/100 calli, 100.0 plantlets/100 calli for Chi31 and 11.1 plantlets/100 calli for А188. Observed reductions in capacityfor plant regeneration of Lancaster inbreds may have been due to their pedigree. These inbreds belong to the commercial heterotic group that was not specially selected for increased regenerative ability, unlike the model inbreds of other heterotic groups. Overall, the level of regeneration frequency in the Lancaster group was 44.8 plantlets/100 calli on the medium under BAP, 41.4 plantlets/100 calli under IBA, and 20.7 plantlets/100 calli with CT. In general, the level of regeneration frequency for non-Lancaster heterotic groups reached 89.7 plantlets/100 calli on the medium with BAP, 96.7 plantlets/100 calli under IBA, and 93.1 plantlets/100 calli under CT. To enhance embryogenesis and frequency of regeneration for maize inbreds of the Lancaster group 30 g/l sucrose in the callusogenesis medium and physiologically active substance indolylbutyric acid (1.0 mg/l) in the medium for regeneration can be recommended.

Improved production of chlorogenic acid from cell suspension cultures of &lt;i&gt;Lonicera macranthoids&lt;/i&gt;

Purpose: To evaluate the potential of Lonicera macranthoides Hand. -Mazz. Yulei1 suspension culture system for enhanced production of the main secondary metabolite, chlorogenic acid.Methods: The callus of L. macranthoides Hand.-Mazz. “Yulei1” was suspension cultured in B5 liquid medium supplemented with different plant growth regulators. Biomass accumulation was calculated by weight method and chlorogenic acid production was measured using high performance liquid chromatography (HPLC). HPLC was carried out on C18 analytical column at 35 °C and the detection wavelength was set at 324 nm.Results: The results showed that maximum accumulation of biomass and chlorogenic acid were achieved 15 days after culture growth. The optimized conditions for biomass accumulation and chlorogenic acid production were 50 g/L of inoculum on fresh weight basis, B5 medium supplemented with plant growth regulators, 30 - 40 g/L sucrose and initial medium pH of 5.5. Maximum accumulation of chlorogenic acid and biomass were observed when the culture medium was supplemented with 2.0 mg/L6-BA. Optimal accumulation of chlorogenic acid was observed using combination of hormones 2.0 mg/L 6-Benzyladenine (BA) + 0.5 mg/L2, 4-Dichlorophenoxyacetic acid (2,4-D), while optimal accumulation of biomass was observed with 2.0 mg/L 6-BA + 2.0 mg/L2, 4-D. In addition, phenylalanine also contributed to the synthesis of chlorogenic acid at a concentration &gt; 50 mg/L.Conclusion: Cell suspension cultures of L. macranthoides Hand.-Mazz. “Yulei1” have successfully been established. The findings provide a potential basis for large scale production of chlorogenic acid using cell suspension cultures of L. macranthoides.Keywords: Lonicera macranthoides, Cell suspension culture, Chlorogenic acid, Phenylalanine, Optimization

The influence of sucrose and maltose on Saccharomyces cerevisiae yeast multiplication

The data on the influence of fermentable carbohydrates concentration on yeast multiplication are widely represented in the literature. This study presents the results of experiments showing an influence of sucrose and maltose concentration on Saccharomyces cerevisiae yeast multiplication. The objects of this research are bakery, beer, wine and alcohol yeast that are widely used in fermentation industry. Beet molasses and malt wort were chosen as nutrient medium for yeast breeding. Their basic sugars are mainly represented by sucrose and maltose. The concentration of sugars was 9, 12, 16 and 20%. The intensity of yeast multiplication was evaluated based on yeast cells concentration during their cultivation and the specific growth rate. Sugar concentrations causing an intensive accumulation of examined yeast strains were determined. This paper presents the experimental data that were received describing the influence of sucrose and maltose concentration on the duration of a lag phase period for different yeast strains. Specific growth rates of researched strains were determined for nutrient mediums with different glucose and maltose concentrations. It was found that the Crabtree effect, that is caused by high carbohydrates concentration in culture medium, is most pronounced when yeast cells grow on a sucrose medium. Brewer’s and baker's yeast are more adapted to high concentrations of carbohydrates. The obtained experimental data could be utilized to develop flow charts of growing a pure culture of Saccharomyces cerevisiae yeast to use at fermentation plants, including low power ones.

The influence of methyl jasmonate, cholesterol and l‐arginine on solasodine production in hairy root culture of Solanum mammosum

The increasing demand of diosgenin for high‐revenue synthesis of steroid hormones by the pharmaceutical industries has driven researchers to look for other alternatives. Solasodine which was reported to be present in Solanum mammosum is known to be a potential source. The present study highlighted that added methyl jasmonate, cholesterol and l‐arginine into the modified liquid full‐strength Murashige and Skoog (MS) medium (with ammonium to nitrate ratio 10.3 mM: 39.4 mM, and 4% (w/v) sucrose) could influence the solasodine production in the hairy roots of S. mammosum. The findings showed that both hairy root line‐ATCC31798 and line‐A4 (which were separately induced by Agrobacterium rhizogenes strain ATCC31798 and A4) acquired solasodine productivity of 4.5 mg/g dry weight roots with average dry biomass of 190 mg after 32 days culture, when using 50 mg fresh weight roots as initial inoculum size, with 100 mM cholesterol, 1000 μM l‐arginine and 300 μM methyl jasmonate added simultaneously into the culture medium on day 20 of culture. The amount of solasodine obtained was five times higher than those without both the elicitor and precursor treatment. The improved solasodine production with a high‐biomass growth could reduce the production cost of steroid synthesis in the long run.

The efficiency of synthesis of β-fructofuranosidase by Debaryomyces hansenii yeast when cultured on a nutrient medium from molasses

Distribution D. hansenii in different substrates can be explained sufficiently high hydrolytic activity, which is a prerequisite for their use in biotechnology to produce various biological products, in particular lytic enzymes. The paper is picked productivity and efficiency of synthesis of extracellular enzyme β-fructofuranosidase D. hansenii yeast nutrient medium from molasses. The efficiency of D. hansenii yeast culture in a nutrient medium of molasses depends primarily on the strain. It was found that the most productive and efficient synthesizing extracellular enzyme β-fructofuranosidase is yeast strain D. hansenii H4651. Maximum productivity and efficiency of the synthesis of the extracellular enzyme β-fructofuranosidase D. hansenii yeast strain H4651 seen when cultured in a nutrient medium from molasses without additional nutrients at a temperature of 20 oC. It was found that the consumption of reducing substances is not an adequate amount of yeast biomass synthesized D. hansenii. The content of reducing substances after 50 hours of cultivation D. hansenii yeast H4651 Uwe-creases. The resulting pattern PB increase in liquid culture may explain synthesis drozh-Jamie D. hansenii β – fructofuranosidase extracellular enzyme which hydrolyzes sucrose medium. The highest specific growth rate observed in yeast D. hansenii H4651 at temperatures cultivated-tion 15 and 20 ° C. Out D. hansenii yeast biomass H4651 exceeds the yield of biomass when cultured yeast D. hansenii strains H433 and H18–3.

ECTOPARASITES AND VIBRIOS ASSOCIATED WITH FATTENING CULTURED MUD CRABS [Scylla serrata (Forsskal, 1775)] FROM PEMALANG COAST, INDONESIA

Infectious of ectoparasites and vibrios were found as a problem in fattening mud crab. The aims of this study were to determine the clinical sign of infected mud crabs and to identify the ectoparasites and generic vibrio in the fattening mud crabs from Pemalang Coast, Indonesia. Ectoparasites were collected by smear method. Whereas, 20 isolates were collected from hepatopancreas, gills, hemolymph and injured carapace of the mud crabs. Thiosulphate Citrate Bile Salt Sucrose (TCBS) medium was used to isolate suspected vibrios. The clinical signs of mud crabs infected by ectoparasites were shown through the damaged gills and the attachment of other organisms on the gills, whereas the clinical signs of mud crabs infected by vibriosis were shown through red spot on carapace and wound in carapace, claw and abdomen, followed by weak condition. It also indicated that seven ectoparasites were Ichthyobodo sp., Epistylis sp., Carchesium sp., Vorticela sp., Octolasmis sp., Lepeophtherius sp, and Copepodit sp., whilst five Vibrios were V. harveyi, V. Cholerae, V. parahaemolyticus, V. alginolyticus and V. fischeri.

Mutation of AN39-1 for production and characterization of constitutive, thermostable and pH-resistant dextransucrase / Konstitutif, sıcaklığa ve pH’ya dayanıklı dekstransukrazların üretimi ve karakterizasyonu için AN39-1’in mutasyonu

Abstract Objective: Leuconostoc mesenteroides AN39-1 has recently been isolated from Crataegus orientalis var. Orientalis. It produces inducible extracellular dextransucrase (EC 2.4.1.5) forming dextran from sucrose. The aim of this study was (1) to obtain constitutive, pH-resistant and thermostable dextransucrase, (2) to characterization of these dextransucrase. Methods: Mutagenesis was carried out on the parent strain (AN39-1) using UV, ethyl methane sulfonate, and N- methyl- N´-nitro-N-nitrosoguanidine. Dextransucrases from wild type (AN39-1) and the mutant strain (A26-2/11) were purified by polyethylene glycol (PEG) precipitation and characterized. Results: Mutants (A26, A26-2, and A26-2/11) hyper producing and constitutive for dextransucrase were isolated. The mutants (A26, A26-2, A26-2/11) produced 7.2, 8.1, and 2.0 times more dextransucrase activity as compared to parent strain on sucrose medium, respectively. In addition, the mutants produced dextransucrase on glucose medium with higher activities (3.0-5.8 times) than what the parental strain produced on sucrose medium. The mutant enzyme (A26-2/11) was much more thermostable than the native enzyme and resistant to pH more than dextransucrase of AN39-1. The dextransucrase from mutant strain was stable up to 35°C and pH of 7.5 for 3 hr. Conclusion: The structures of dextrans produced by wild type and mutant enzymes were similar to commercially produced B-512 F dextran. Thus, the newly dextransucrases produced by mutant strain could find industrial applications at higher temperature and pH.

Cellulose Deficiency Is Enhanced on Hyper Accumulation of Sucrose by a H+-Coupled Sucrose Symporter.

In order to understand factors controlling the synthesis and deposition of cellulose, we have studied the Arabidopsis (Arabidopsis thaliana) double mutant shaven3 shaven3-like1 (shv3svl1), which was shown previously to exhibit a marked cellulose deficiency. We discovered that exogenous sucrose (Suc) in growth medium greatly enhances the reduction in hypocotyl elongation and cellulose content of shv3svl1 This effect was specific to Suc and was not observed with other sugars or osmoticum. Live-cell imaging of fluorescently labeled cellulose synthase complexes revealed a slowing of cellulose synthase complexes in shv3svl1 compared with the wild type that is enhanced in a Suc-conditional manner. Solid-state nuclear magnetic resonance confirmed a cellulose deficiency of shv3svl1 but indicated that cellulose crystallinity was unaffected in the mutant. A genetic suppressor screen identified mutants of the plasma membrane Suc/H(+) symporter SUC1, indicating that the accumulation of Suc underlies the Suc-dependent enhancement of shv3svl1 phenotypes. While other cellulose-deficient mutants were not specifically sensitive to exogenous Suc, the feronia (fer) receptor kinase mutant partially phenocopied shv3svl1 and exhibited a similar Suc-conditional cellulose defect. We demonstrate that shv3svl1, like fer, exhibits a hyperpolarized plasma membrane H(+) gradient that likely underlies the enhanced accumulation of Suc via Suc/H(+) symporters. Enhanced intracellular Suc abundance appears to favor the partitioning of carbon to starch rather than cellulose in both mutants. We conclude that SHV3-like proteins may be involved in signaling during cell expansion that coordinates proton pumping and cellulose synthesis.

Mitochondrial gamma carbonic anhydrases are required for complex I assembly and plant reproductive development.

Complex I of the mitochondrial electron transport chain (mETC) in plants contains an extra domain that is made up from proteins homologous to prokaryotic gamma-carbonic anhydrases (γCA). This domain has been suggested to participate in complex I assembly or to support transport of mitochondrial CO2 to the chloroplast. Here, we generated mutants lacking CA1 and CA2 - two out of three CA proteins in Arabidopsis thaliana. Double mutants were characterized at the developmental and physiological levels. Furthermore, the composition and activity of the mETC were determined, and mutated CA versions were used for complementation assays. Embryo development of double mutants was strongly delayed and seed development stopped before maturation. Mutant plants could only be rescued on sucrose media, showed severe stress symptoms and never produced viable seeds. By contrast, callus cultures were only slightly affected in growth. Complex I was undetectable in the double mutants, but complex II and complex IV were upregulated concomitant with increased oxygen consumption in mitochondrial respiration. Ectopic expression of inactive CA variants was sufficient to complement the mutant phenotype. Data indicate that CA proteins are structurally required for complex I assembly and that reproductive development is dependent on the presence of complex I.

English

Thermotolerant yeasts, which are expected to be applicable for high-temperature fermentation as an economical process, were isolated from four provinces in Laos. Of these yeasts, five isolates exhibited stronger fermentation abilities in a 16% sugars-containing medium of glucose, sucrose, sugarcane or molasses at 40°C than that of Kluyveromyces marxianus DMKU 3-1042, one of the most thermotolerant and efficient yeasts isolated previously in Thailand. One of the five strains, BUNL-17, exhibited the highest ethanol fermentation performance at 45°C. Yeast identification was achieved by whole-cell matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) analysis as well as by nucleotide sequencing of the D1/D2 domain of the large subunit rRNA gene, revealing that the isolated strains can be categorized into Pichia kudriavzevii, Cyberlindnera rhodanensis and K. marxianus and that all of the five strains are K. marxianus. The results of this study showed that the former analysis is much faster than the latter and reliable and equivalent to the latter. Key words: Ethanol fermentation, thermotolerant yeast, Kluyveromyces marxianus.

Effects of abscisic acid and an osmoticum on the maturation, starch accumulation and germination of Picea spp. somatic embryos

The aim of this study was to investigate whether ABA, sucrose or Phytagel applied to the maturation medium at different concentrations affected the growth, development and starch content of somatic embryos of Picea abies and Picea omorika. Embryogenic tissues of both spruce species were placed on maturation medium supplemented with various doses of ABA (10, 20, 40 and 80 µM), sucrose (17, 34 and 68 g/L) or Phytagel (4, 6 and 8 g/L). Our results showed that ABA and the osmoticum had a significant effect on the production and maturation of somatic embryos of both spruce species. Supplementing the medium with low concentrations of ABA (10 µM) or sucrose (17 g/L) resulted in the precocious germination of embryos. Adding sucrose to the maturation medium at the highest tested concentration (68 g/L) improved the growth of the radicles of the embryos of both spruce species during the germination stage. Moreover, the intensity of the growth of the hypocotyls and radicles of P. omorika germinating embryos depended on the Phytagel concentration applied to the maturation medium. The starch content and the starch accumulation pattern of Picea abies and P. omorika somatic embryos were dependent on the concentration of ABA, sucrose or Phytagel in the maturation medium. In general, during development, the P. abies somatic embryos accumulated a much greater amount of starch than P. omorika embryos did. The effects of ABA and osmoticum on the starch accumulation pattern of Picea abies and P. omorika somatic embryos are first reported in this paper.

Membrane roughness as a sensitive parameter reflecting the status of neuronal cells in response to chemical and nanoparticle treatments.

BackgroundCell membranes exhibit abundant types of responses to external stimulations. Intuitively, membrane topography should be sensitive to changes of physical or chemical factors in the microenvironment. We employed the non-interferometric wide-field optical profilometry (NIWOP) technique to quantify the membrane roughness of living neuroblastoma cells under various treatments that could change the mechanical properties of the cells.ResultsThe membrane roughness was reduced as the neuroblastoma cell was treated with paclitaxel, which increases cellular stiffness by translocating microtubules toward the cell membranes. The treatment of positively charged gold nanoparticles (AuNPs) showed a similar effect. In contrast, the negatively charged AuNPs did not cause significant changes of the membrane roughness. We also checked the membrane roughness of fixed cells by using scanning electron microscopy (SEM) and confirmed that the membrane roughness could be regarded as a parameter reflecting cellular mechanical properties. Finally, we monitored the temporal variations of the membrane roughness under the treatment with a hypertonic solution (75 mM sucrose in the culture medium). The membrane roughness was increased within 1 h but returned to the original level after 2 h.ConclusionsThe results in the present study suggest that the optical measurement on membrane roughness can be regarded as a label-free method to monitor the changes in cell mechanical properties or binding properties of nanoparticles on cell surface. Because the cells were left untouched during the measurement, further tests about cell viability or drug efficacy can be done on the same specimen. Membrane roughness could thus provide a quick screening for new chemical or physical treatments on neuronal cells.

Vodka production from potato (Solanum tuberosum L.) using threeSaccharomyces cerevisiaeisolates

The efficacy of three strains of Saccharomyces cerevisiae in the production of vodka from potato hydrolysate was evaluated. For each isolate, two treatments were performed: one containing potato hydrolysate (11% w/w of soluble solids) and the other containing potato hydrolysate supplemented with sucrose (17% w/w) in the fermentation medium. The best results were obtained using a baker's yeast in the second treatment, which showed higher substrate-to-product conversion (0.47 g ethanol g−1 total reducing sugars), higher fermentation yield (91.4%) and a higher ethanol content (6.05% v/v). Following fermentation, the medium was clarified using centrifugation, and two successive distillations and filtrations were conducted. The results were examined by referring to the standards for vodka, as established by Brazilian legislation. The ethanol concentration (39.7% v/v) fell within the legally stipulated range, and the levels of copper and furfural remained undetectable. However, the methanol (35.04 mg 100 mL−1 of anhydrous alcohol) content and the levels of some secondary compounds (148.33 mg 100 mL−1) were both higher than the guidelines (20 and ≤50 mg 100 mL−1, respectively). Copyright © 2016 The Institute of Brewing & Distilling

Surface plasmon resonance sensor based on a new opto-mechanical scanning mechanism

Surface plasmon resonance (SPR) is employed as one of the key phenomena in biological, chemical and gas sensors. In this paper, we report development of a Kretschmann configuration based SPR sensing instrument by adopting a unique opto-mechanical scanning mechanism. The new scanning mechanism ensures portable, very low-cost and sensitive SPR sensor. In contrary to the traditional scanning mechanism, we utilized a rotating mirror for changing angle of incidence, and a quadrant photodiode (QPD) for recording reflected intensity. In order to achieve constant spot measurement on the sensing area (gold surface) for a fixed referencing, the prism-sensor assembly is translated vertically in a highly controlled manner governed by a feedback mechanism. In the feedback mechanism, the deflection of reflected beam is quantified by the QPD, and the prism-sensor assembly is translated vertically so as to regain the original set point. The SPR spectra of different materials deposited onto the gold surface using different techniques were collected and studied. Using the developed SPR instrument with pure gold sensing surface, the lowest detectable concentration of the sucrose in aqueous medium was found to be 100femto-molar. The sensitivity of the instrument was estimated using the different concentration of aqueous solutions of sucrose with known refractive indices, and it was found to be around 52.6°/RIU. These studies indicate a high resolution and good sensitivity of the instrument.