Improved embryoid induction and green shoot regeneration from wheat anthers cultured in medium with maltose

Summary Anthers from spring wheat (Triticum aestivum L.) genotypes, including six F₁ hybrids, were cultured in a modified liquid N6 medium containing either sucrose or maltose. In every case, use of maltose resulted in greater microspore callus induction and green shoot regeneration than culture in sucrose-containing medium. Induction in maltose medium also allowed green shoots to be recovered from crosses that showed only a poor response in other media and from two genotypes that did not respond to modified N6 medium with sucrose. Replacement of sucrose with maltose generally resulted in microspores having a more embryogenic mode of development in which distinct embryoids often formed. The most responsive genotype produced over 200 green shoots/100 anthers when cultured in medium with maltose.NRCC publication no. 31494     

Carbohydrate and osmotic requirements for high-frequency plant regeneration from protoplast-derived colonies of indica and japonica rice varieties

The effects were studied of various carbohydrates and osmoticstress, created by high agarose or carbohydrate concentrations,on the regeneration of fertile plants from protoplast-denvedcolonies of several indica (IR43, Jaya, Pusa Basmati 1) andjaponica (Taipei 309) rice varieties. Observations of the culturesdeveloped on media containing one of these carbohydrates (cellobiose,fructose, glucose, lactose, maltose, mannitol, sorbitol or sucrose),each at 88 mM, indicated that maltose was the preferential carbonsource for the proliferation of embryogenic callus and shootregeneration. Maltose-containing medium induced shoot formationin 24–66% of the protoplast-derived tissues, dependingupon the rice variety, compared to shoot regeneration from 4–32%of the tissues in sucrose-supplemented medium. Media containing288 mM maltose or an equimolar combination of 88 mM maltoseand 200 mM mannitol, caused water loss from calli and promotedthe growth of embryogenic calli. These calli formed shoots withgreater frequencies when subsequently transferred to shoot regenerationmedium with 88 mM maltose. A medium containing 88 mM maltoseand semi-solidified with 1.0% (w/v) instead of 0.5% (w/v) agarosehad a similar beneficial effect on the growth of embryogeniccalli and simultaneously supported high-frequency (48–55%)shoot formation. The optimum shoot regeneration frequencies(60–78%) were obtained when protoplast-derived colonieswere serially cultured on to shoot regeneration medium containing1.0% (w/v) agarose for 4 weeks, followed by a 2-week cultureperiod on the same medium with 0.5% (w/v) agarose. Plants regeneratedon medium containing maltose and/or 1.0% (w/v) agarose werephenotypically normal and fertile. Key words: Carbohydrates, Oryza sativa L, indica and japonica rice, osmotic stress, plant regeneration, protoplast-derived colonies     

Ethanol addition on inactivation of Saccharomyces pastorianus by a two‐stage system with low‐pressure carbon dioxide microbubbles can accelerate the cell membrane injury

The effect of ethanol on the inactivation of Saccharomyces pastorianus by a two‐stage system with low‐pressure carbon dioxide microbubbles (two‐stage MBCO₂) was investigated. Zero and >5 log reductions of S. pastorianus populations suspended in physiological saline (PS) containing 0% and 10% ethanol, respectively, occurred by the two‐stage MBCO₂ at a mixing vessel pressure of 1 MPa and a heating coil temperature of 40°C. Conversely, the detected number of surviving S. pastorianus cells in PS containing 5% ethanol was higher in yeast and mold agar (YMA, an optimum agar) than YMA with 2.5% sodium chloride, followed by yeast nitrogen base agar (YNBA, a minimum agar). The fluorescence polarization of S. pastorianus in PS containing 5% and 10% ethanol increased similarly with exposure time in the heating coil of two‐stage MBCO₂ and was correlated with the surviving cell number measured in YNBA. The intracellular pH (pH_in) of S. pastorianus in PS containing 5% ethanol decreased linearly with exposure time in the heating coil of two‐stage MBCO₂. Also, the pH_in‐lowering of S. pastorianus in PS containing 10% ethanol was drastically caused by two‐stage MBCO₂ at 1 min exposure time in the heating coil but then stayed constant until 5 min, agreeing with the inactivation efficiency. Therefore, ethanol in S. pastorianus suspension was suggested to accelerate the cell membrane injury caused by two‐stage MBCO₂. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:282–286, 2018     

Influence of sugars and light on rhizosecretion of α-glucosidase and acid phosphatase during micropropagation of potato

The effects of carbohydrate supply and light on rhizosecretion during micropropagation of potato plantlets (Solanum tuberosum L., cv. ‘Iwa’) in liquid medium were investigated. Soluble protein content was higher in the spent medium for plantlets grown under light conditions than in the dark. For those plantlets grown under light conditions and on different sugar-supplemented media, they rhizosecreted the highest amount of soluble protein when grown in the presence of maltose, while they rhizosecreted the lowest amount of soluble protein when grown on medium containing glucose. Moreover, plantlets grown under light and on a medium containing sucrose were the most vigorous, and exhibited the highest levels of rhizosecreted acid phosphatase activity. However, there was no direct relationship between plantlet growth and rhizosecretion. When plantlets were grown in the dark and on medium containing maltose, a higher α-glucosidase activity was detected than those grown on medium containing sucrose. These results suggested that rhizosecretion of certain proteins from plantlets grown in vitro might not require exposure to light conditions.     

Utilisation of maltose and glucose by lactobacilli isolated from sourdough

Abstract The utilisation of glucose and maltose was investigated with Lactobacillus strains isolated from sourdough starters. These preparations have been in continuous use for a long period to produce sourdough from rye, wheat and sorghum. The major metabolic products formed by resting cells from glucose or maltose were lactate, ethanol and acetate. Upon fermentation of maltose, resting cells of Lactobacillus sanfrancisco, L. reuteri, L. fermentum and Lactobacillus ep. released up to 13.8 mM glucose after 8 h. The ratio of released glucose per mol of utilised maltose was up to 1:1. Glucose formation was high when starved cells of L. sanfrancisco and Lactobacillus sp. were used. This is consistent with maltose utilisation via maltose phosphorylase which phosphorylates maltose without the expenditure of ATP and thus allows the cell to waste glucose in the presence of abundant maltose. The glucose formed may be utilised by the lactobacilli or other microorganisms, e.g. yeasts. However, the release of glucose into the medium by sourdough lactobacilli prevents competitors from utilising the abundant maltose by glucose repression. In strains of L. sanfrancisco , maltose utilisation was very effective and not subject to glucose repression. Therefore, they overgrow other microorganisms sharing this habitat. Wild isolates of L. sanfrancisco were initially unable to grow on glucose. Upon growth on maltose such strains required adaptation times of up to 150 h to grow on glucose. After subsequent transfer of glucose-grown cells to fresh medium the strains resumed growth both on glucose or maltose. They readily lost their ability to grow on glucose upon exposure to maltose. L. sanfrancisco exhibited biphasic growth characteristics on media containing glucose, maltose or both carbon sources. Evidence is provided that biphasic growth and metabolite formation are dependent on the redox potential.     

Butanol production by hypersolvent-producing mutant Clostridium beijerinckii BA101 in corn steep water medium containing maltodextrin

Clostridium beijerinckii NCIMB 8052 parent strain and BA101, a hypersolvent-producing mutant, fermented 6% (w/v) glucose, maltodextrin, maltose or xylose in a medium containing corn steep water (CSW) to produce butanol. Batch fermentation in an unoptimized 6% (w/v) maltodextrin plus 1.6% solids CSW medium demonstrated that C. beijerinckii NCIMB 8052 and BA101 produced 10.7 g butanol/L and 14.5 g butanol/L, respectively.     

Taxonomic note "Lactobacillus pastorianus" (Van Laer, 1892) a former synonym for Lactobacillus paracollinoides

"Lactobacillus pastorianus" (Van Laer, 1892) is not a validly described species and is not included in the Approved List of Bacterial Names. The strain is available in multiple culture collections as Lactobacillus sp. DSM 20197, L. brevis ATCC 8291, "L. pastorianus" CECT 5926, L. brevis JCM 1113, and "L. pastorianus" LMG 11990. Nearly identical 16S rRNA sequences and protein encoding genes for 6-phosphogluconate dehydrogenase (99.9%) revealed this strain as L. paracollinoides. A 16S-23S rRNA intergenic spacer region-based PCR assay did not differentiate "L. pastorianus" DSM 20197 from L. paracollinoides DSM 15502(T). Highly similar RAPD profiles differentiated both strains below species level.     

Repetitive somatic embryogenesis and plant recovery in white clover

Summary Breeding and selection was used to generate a population of white clover (Trifolium repens L.) from cultivar Osceola with a high embryogenic capacity. Somatic embryos were obtained from immature cotyledons of white clover placed onto EC6 basal medium containing 40 mg L^–1 of 2,4-D and 6% sucrose. The effects of 2,4-D at 20 and 40 mg L^–1 and of the carbohydrates, sucrose and maltose, were evaluated for their influence in the establishment of repetitive somatic embryogenesis. To determine the optimal protocol for plant recovery from somatic embryos, the effects of MS vs. EC6 basal salts, sucrose vs. maltose, B5 vitamins vs. yeast extract, and inclusion or exclusion of activated charcoal were evaluated. Repeated subculture of white clover somatic embryos on EC6 basal medium containing 6% sucrose with 2,4-D at 20 or 40 mg L^–1 effectively maintains repetitive embryogenesis. Medium containing MS salts with 6% maltose as the carbohydrate source was the most efficient for plant recovery.     

Intracellular superoxide dismutase,catalase, and glutathione peroxidase activities and membrane lipid peroxide levels in Fusarium acuminatum upon environmental changes in a defined medium

The variations of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities and lipid peroxide (LPO) levels in Fusarium acuminatum, an aerobic filamentous fungus, were investigated depending on the carbon and nitrogen sources during the incubation period. Fungus was cultivated in growing medium containing either maltose or saccharose in 5-25 g/L concentration range as a carbon source and either glycine or peptone in 5-35 g/L concentration range as a nitrogen source at 28 degrees C and 100 rpm. The observed highest SOD, CAT, and GSH-Px activities were 31.2+/-0.655, 62.5+/-5.23, and 1.52+/-0.0122 IU/mg in the presence of 20 g/L maltose and 73.96+/-1.48, 74.46+/-2.94, 3.48+/-0.083 IU/mg in the 15 g/L glycine-containing medium at 16 days, respectively. At the same time, the minimum LPO level was observed at 20 g/L maltose and 15 g/L glycine compared with the other carbon and nitrogen sources. The results showed a negative correlation between antioxidant enzyme activities and membrane LPO levels in F. acuminatum cells.     

A MUCILAGE-FORMING LACTOBACILLUS SPECIES ISOLATED FROM CIDER. PART II. POLYSACCHARIDE FORMATION

SUMMARY: Cultures grown at 25° under an atmosphere of CO₂ in a medium containing maltose, inorganic salts and ethanolic extracts of peptone and yeast autolysate produced a polysaccharide, which was isolated and purified. Examination by a variety of chemical and biological methods indicated that it was a dextran of low molecular weight.     

Improvement of green plant regeneration by manipulation of anther culture induction medium of hexaploid wheat

Anthers of three hexaploid wheat (Triticum aestivum L.) genotypes with high frequencies of albino regenerants in anther culture were compared to DH after inoculation on medium supplemented with ficoll, colchicine or maltose separately, pair-wise or combined, in an attempt to increase green plant regeneration. Maltose treatment produced more green regenerated plants than sucrose for all of the genotypes. The three chemicals combined in anther medium either reduced green plant regeneration or did not yield significantly different numbers of green regenerated plants compared to the maltose treatment. With DH fewer embryo-like structures (ELS) were obtained per 100 cultured anthers on all medium containing colchicine but greater frequencies of green plants per 100 ELS were obtained. It appeared that the increase in green regenerated plants per 100 ELS was due to a better quality of embryos that were capable of regenerating into green rather than albino plantlets. Smaller increases in green plants per 100 ELS were observed in ICR 4 and V-15 on colchicine containing medium compared to DH. Genotypic differences in anther culture response were observed for ELS per 100 cultured anthers (increased for V-37, decreased for DH and approx. the same for ICR 4 and V-15 in medium with all three chemicals compared to the sucrose control).     

Variants of soybean cells which can grow in suspension with maltose as a carbon-energy source

Suspension cultures of soybean line SB-1 have been grown using maltose as an carbon-energy source. The very slow growth in medium containing maltose has been used to select rapidly growing variants. These appear to arise as a series of sequential genetic changes (mutations?). These variant strains are stable when grown in sucrose medium for 100 generations and appear to be able to transport maltose actively into the cell.     

甘蓝型油菜花粉离体培养

通过对甘蓝型油菜花粉发育阶段和活力的检测确定花粉发育的时期,分离出单核晚期花粉进行离体培养.结果表明,(1)筛选出适合油菜小孢子花粉离体培养的液体培养基为T_1+怀特维生素(White's vitamins)+2%椰子汁+0.5 mol/L麦芽糖,在此培养基上花粉的成熟率可达25.1%,萌发率达6.3%.(2)筛选出适合成熟花粉离体萌发液体培养基为0.6 mol/L麦芽糖+1.6 mmol/L硼酸+2.9 mmol/L硝酸钙+29.6 μmol/L VB_1,在此培养基上,自然成熟花粉的萌发率可达75.2%.将离体培养成熟的花粉培养在萌发培养基,萌发的花粉占成熟花粉的66.3%.     

Somatic embryogenesis in Citrus SPP.: Carbohydrate stimulation and histodifferentiation

Summary Somatic embryogenesis from nucellus-derived callus cultures of five cultivars, including three (Caipira, Seleta Vermelha, and Valencia) of sweet oranges (C. sinesis L. Osbeck), Rangpur lime (C. limonia L. Osbeck), and Cleopatra mandarin (C. reticulata Blanco) (lines I and II), were studied. Callus lines maintained on MT medium supplemented with 50 g l⁻¹ sucrose were transferred to MT medium supplemented with different carbohydrate sources: galactose, glucose, lactose, maltose, or sucrose at 18, 37, 75, 110, or 150 mM, or glycerol at 6, 12, 24, 36, or 50 mM. Globular embryos were observed after approximately 4 wk, in several treatments. Cultures of Valencia and Caipira sweet oranges and Cleopatra mandarin (line I) showed high numbers of embryos on medium containing galactose, lactose, and maltose. Histological studies showed somatic embryos in all developmental stages with a normal histodiffeentiation pattern. The other two cultivars (Rangpur lime and Cleopatra mandarin, line II) formed very few embryos, which did not develop further following the globular stage. Some of the abnormalities observed were lack or dedifferentiation of protoderm and absence of apical meristems and procambial strands. Embryos that followed the normal sequence of development were easily converted into plants. Non-embryogenic cultures continued as proliferating callus cultures, eventually forming a few embryos which did not convert into plants. Statistical analyses of the callus response to carbohydrate treatments was done using an overdispersion Poisson model.     

Relative importance of maltose and sucrose supplied during a 2-step potato microtuberization process

A 2-stage in vitro tuberization process comprising first micropropagation via nodal explants and then tuber induction in the resultant in vitro plantlets was studied using 2 cultivars of potato, Iwa and Daeji. In particular, the effects on both plantlet growth and subsequent in vitro tuberization of Murashige and Skoog (1962) basal medium containing either sucrose or maltose, each at 3 % (w/v), used for micropropagation were investigated. Sucrose and maltose were found to be equally effective in supporting development of vigorous plantlets from the nodal explants of both potato cultivars. Upon transfer to a medium with an optimised level of sucrose (i.e. 8 %, w/v) for in vitro tuberization, only the plantlets previously grown in the sucrose-containing medium were capable of forming more microtubers of the larger size category (greater than 0.5 g). The relative importance of sucrose supply at the mircropropagation stage was further confirmed when the resultant plantlets grown in the 3 % sucrose-containing medium were transferred to an in vitro tuberization medium containing either sucrose or maltose, each at 8 % (w/v). In this experiment, maltose and sucrose had indistingushable effects on in vitro tuberization.     

Mechanism of maltose uptake and glucose excretion in Lactobacillus sanfrancisco.

Lactobacillus sanfrancisco LTH 2581 can use only glucose and maltose as sources of metabolic energy. In maltose-metabolizing cells of L. sanfrancisco, approximately half of the internally generated glucose appears in the medium. The mechanisms of maltose (and glucose) uptake and glucose excretion have been investigated in cells and in membrane vesicles of L. sanfrancisco in which beef heart cytochrome c oxidase had been incorporated as a proton-motive-force-generating system. In the presence of ascorbate, N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), and cytochrome c, the hybrid membranes facilitated maltose uptake against a concentration gradient, but accumulation of glucose could not be detected. Similarly, in intact cells of L. sanfrancisco, the nonmetabolizable glucose analog alpha-methylglucoside was taken up only to the equilibration level. Selective dissipation of the components of the proton and sodium motive force in the hybrid membranes indicated that maltose is transported by a proton symport mechanism. Internal [14C]maltose could be chased with external unlabeled maltose (homologous exchange), but heterologous maltose/glucose exchange could not be detected. Membrane vesicles of L. sanfrancisco also catalyzed glucose efflux and homologous glucose exchange. These activities could not be detected in membrane vesicles of glucose-grown cells. The results indicate that maltose-grown cells of L. sanfrancisco express a maltose-H+ symport and glucose uniport system. When maltose is the substrate, the formation of intracellular glucose can be more rapid than the subsequent metabolism, which leads to excretion of glucose via the uniport system.     

Improved formation of regenerable callus in isolated microspore culture of maize: impact of carbohydrates, plating density and time of transfer

 Pure fractions of maize (Zea mays L.) microspores at various densities were exposed to defined media containing different concentrations of maltose and sucrose. In general, lower carbohydrate concentrations (60, 90 g/l) yielded higher frequencies of embryo-like structures than a high concentration (120 g/l). Optimum cell density seemed to depend on the genotype, but densities above 80,000 microspores/ml led to reduced embryogenesis in all genotypes tested. Direct comparison of maltose and sucrose as carbohydrate source in the induction medium clearly demonstrated the superiority of maltose with regard to the regeneration frequency. For two out of three genotypes tested, maltose also enhanced the formation of embryo-like structures. The time of embryo transfer to callus induction media had a significant effect on regeneration frequency. Received: 26 September 1997 / Revision received: 5 November 1998 / Accepted 24 March 1999     

Improvement of somatic embryogenesis in wild cherry (Prunus avium). Effect of maltose and ABA supplements

Three different types of morphogenesis were identified in embryogenic cultures of Prunus avium grown on a proliferation medium containing 0.54 μM NAA, 0.46 μM kinetin and 0.44 μM BA: a friable hyperhydric callus, repetitive embryogenesis and an embryogenic tissue. Translucent and white somatic embryos were produced from the three types of morphogenesis but mainly from the embryogenic tissue. These somatic embryos showed histological and cytological teratological features such as highly differentiated cells with shrunken cytoplasm and destructured nuclei. For the four lines studied, somatic embryo production was improved by transferring the embryogenic tissue to developmental media without auxin and cytokinin but supplemented with maltose alone or maltose and 10 μM ABA. Three weeks after transfer, the line showing the most embryogenesis produced 1404 somatic embryos per gram of embryogenic tissue. A concentration of 263 mM maltose significantly increased the number of white somatic embryos for L 10 line, while translucent somatic embryo production was improved by 88 mM maltose for L 16 line. The combination of maltose and ABA produced different effects with each line. When used with 88 mM maltose, 10 μM ABA significantly increased white somatic embryo production for two lines but decreased the production for one line. When combined with 263 mM maltose, ABA had no effect on white somatic embryo production but significantly decreased the number of translucent somatic embryos. Cells of white somatic embryos contained protein storage reserves and numerous lipid bodies, while those of translucent embryos did not contain storage reserves or lipid bodies. After a two-month cold treatment conversion rate of white and translucent somatic embryos reached 8.5% and 35.2% respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

碳源对早花百子莲愈伤组织诱导及其增殖的生理特性影响

为揭示碳源对早花百子莲愈伤组织诱导与增殖的影响机理,该研究以早花百子莲的小花梗为外植体,比较分析30.0 g/L蔗糖、葡萄糖、麦芽糖在愈伤组织诱导、增殖中的效果,测定不同碳源种类处理下愈伤组织增殖相关生理特性,并根据细胞增殖效果、生理指标相关性进行优化验证。结果表明:(1)蔗糖、葡萄糖和麦芽糖碳源处理下,愈伤组织诱导率分别为86.00%、72.00%和59.67%,蔗糖碳源的愈伤组织诱导率比葡萄糖和麦芽糖分别显著提高19.44%和44.13%(P<0.05),蔗糖碳源较葡萄糖和麦芽糖碳源的愈伤组织大小分别显著增加22.44%和90.09%(P<0.05);愈伤组织增殖阶段,蔗糖碳源能够同时维持良好的细胞增殖效率及活性,而葡萄糖碳源的愈伤组织增殖快、状态差,麦芽糖处理增殖慢、状态佳;蔗糖转换葡萄糖碳源后愈伤组织细胞团大小、细胞活性明显下降;蔗糖转换蔗糖、蔗糖转换麦芽糖的效果较好。(2)培养基碳源显著调节愈伤组织增殖阶段的糖代谢、内源激素代谢和氧化胁迫平衡。(3)愈伤组织的主要糖组分为淀粉、葡萄糖;淀粉、麦芽糖含量与细胞团大小相关性高,以蔗糖为碳源的培养基中添加麦芽糖,愈伤组织...     

Studies on Osmophilic Yeasts

Assimilation of galactose and maltose by Saccharomyces rouxii, which is a typical salt-tolerant yeast playing an important role in soy-brewing, was negligible or extremely poor in the medium containing 18% NaCl, although the assimilation in the ordinary medium was vigorous. The yeasts which were able to assimilate and ferment galactose, maltose and/or saccharose in the high-saline medium were limited to a few strains. From the studies on balances of fermentation products, it was revealed that ethanol yield based on sugar consumed in the 18% NaCl-medium was lower than that in the ordinary medium, suggesting that other fermentation products than ethanol should be accumulated. Analytical results of the fermented broths showed much polyalcohol production in the high-saline medium.