Lignification of developing maize (Zea mays L.) endosperm transfer cells and starchy endosperm cells

Science.gov (United States)

Rocha, Sara; Monjardino, Paulo; Mendonça, Duarte; da Câmara Machado, Artur; Fernandes, Rui; Sampaio, Paula; Salema, Roberto

2014-01-01

Endosperm transfer cells in maize have extensive cell wall ingrowths that play a key role in kernel development. Although the incorporation of lignin would support this process, its presence in these structures has not been reported in previous studies. We used potassium permanganate staining combined with transmission electron microscopy – energy dispersive X-ray spectrometry as well as acriflavine staining combined with confocal laser scanning microscopy to determine whether the most basal endosperm transfer cells (MBETCs) contain lignified cell walls, using starchy endosperm cells for comparison. We investigated the lignin content of ultrathin sections of MBETCs treated with hydrogen peroxide. The lignin content of transfer and starchy cell walls was also determined by the acetyl bromide method. Finally, the relationship between cell wall lignification and MBETC growth/flange ingrowth orientation was evaluated. MBETC walls and ingrowths contained lignin throughout the period of cell growth we monitored. The same was true of the starchy cells, but those underwent an even more extensive growth period than the transfer cells. Both the reticulate and flange ingrowths were also lignified early in development. The significance of the lignification of maize endosperm cell walls is discussed in terms of its impact on cell growth and flange ingrowth orientation. PMID:24688487

Advances in Maize Transformation Technologies and Development of Transgenic Maize.

Science.gov (United States)

Yadava, Pranjal; Abhishek, Alok; Singh, Reeva; Singh, Ishwar; Kaul, Tanushri; Pattanayak, Arunava; Agrawal, Pawan K

2016-01-01

Maize is the principal grain crop of the world. It is also the crop where genetic engineering has been employed to a great extent to improve its various traits. The ability to transform maize is a crucial step for application of gene technology in maize improvement. There have been constant improvements in the maize transformation technologies over past several years. The choice of genotype and the explant material to initiate transformation and the different types of media to be used in various stages of tissue culture can have significant impact on the outcomes of the transformation efforts. Various methods of gene transfer, like the particle bombardment, protoplast transformation, Agrobacterium -mediated, in planta transformation, etc., have been tried and improved over years. Similarly, various selection systems for retrieval of the transformants have been attempted. The commercial success of maize transformation and transgenic development is unmatched by any other crop so far. Maize transformation with newer gene editing technologies is opening up a fresh dimension in transformation protocols and work-flows. This review captures the various past and recent facets in improvement in maize transformation technologies and attempts to present a comprehensive updated picture of the current state of the art in this area.

Regeneration of Sudanese maize inbred lines and open pollinated ...

African Journals Online (AJOL)

STORAGESEVER

2008-06-03

Jun 3, 2008 ... Callus induction capacity was highest in inbred lines IL3, IL15 and IL1. The. Varieties Hudiba-2 and ... Maize plant regeneration can take place through two avenues, that is ..... regenerants were tussel ear formation and dwarfism. These abnormalities are typical of tissue-cultured cells, plants derived from ...

Maize EMBRYO SAC family peptides interact differentially with pollen tubes and fungal cells.

Science.gov (United States)

Woriedh, Mayada; Merkl, Rainer; Dresselhaus, Thomas

2015-08-01

EMBRYO SAC1-4 (ES1-4) peptides belong to the defensin subgroup of cysteine-rich peptides known to mediate pollen tube burst in Zea mays (maize). ES1-4 are reported here to also be capable of inhibiting germination and growth of the maize fungal pathogens Fusarium graminearum and Ustilago maydis at higher concentrations. Dividing the peptides into smaller pieces showed that a 15-amino-acid peptide located in a highly variable loop region lacking similarity to other defensins or defensin-like peptides binds to maize pollen tube surfaces, causing swelling prior to burst. This peptide fragment and a second conserved neighbouring fragment showed suppression of fungal germination and growth. The two peptides caused swelling of fungal cells, production of reactive oxygen species, and finally the formation of big vacuoles prior to burst at high peptide concentration. Furthermore, peptide fragments were found to bind differently to fungal cells. In necrotrophic F. graminearum, a peptide fragment named ES-d bound only at cell surfaces whereas the peptide ES-c bound at cell surfaces and also accumulated inside cells. Conversely, in biotrophic U. maydis, both peptide fragments accumulated inside cells, but, if applied at higher concentration, ES-c but not ES-d accumulated mainly in vacuoles. Mapping of peptide interaction sites identified amino acids differing in pollen tube burst and fungal response reactions. In summary, these findings indicate that residues targeting pollen tube burst in maize are specific to the ES family, while residues targeting fungal growth are conserved within defensins and defensin-like peptides. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Sequencing, assembly, and annotation of Maize B104 : A maize transformation resource

Science.gov (United States)

Maize transformation is complicated. Most lines are not readily cultured and transformed, making the germplasm available for genome engineering extremely limited. Developing a better understanding of the genomic regions responsible for differences in culturability and transformability would be a goo...

In-vitro mutation breeding technology in maize

International Nuclear Information System (INIS)

Nesticky, M.

1988-08-01

Gamma-irradiation and in-vitro culture, separately or combined, as a tool for inducing mutation in maize were evaluated. This type of research has been hampered in maize because (i) maize is a cross pollinating crop and highly heterozygous and (ii) embryogenesis and plant regeneration of plants from in-vitro culture have been difficult. In the present study, carefully designed and elaborated experiments were conducted using an inbred line CH1 31 which is capable of somatic embryogenesis for the subject of mutagenesis and another line Bu 8Ro 2 for the test cross partner. Results showed: 1) Both the regeneration of plants from in-vitro culture and gamma-irradiation induced a similar spectrum of morphological variation. Although the variation with somaclones was more frequent that radiation induced mutations under the conditions used, combination of explant irradiation and in-vitro culture gave the highest frequencies of genetic variation. 2) Some of the mutations in quantitative characters can be recogned in heterozygous state. 3) Mutation can cause variation in combining ability (extent of heterosis). 4) Efficiency at embryogenesis differs with genotypes of maize. 3 refs, 11 figs, 4 tabs

Cytoplasmic pH dynamics in maize pulvinal cells induced by gravity vector changes

Science.gov (United States)

Johannes, E.; Collings, D. A.; Rink, J. C.; Allen, N. S.; Brown, C. S. (Principal Investigator)

2001-01-01

In maize (Zea mays) and other grasses, changes in orientation of stems are perceived by pulvinal tissue, which responds to the stimulus by differential growth resulting in upward bending of the stem. The amyloplast-containing bundle sheath cells are the sites of gravity perception, although the initial steps of gravity perception and transmission remain unclear. In columella cells of Arabidopsis roots, we previously found that cytoplasmic pH (pH(c)) is a mediator in early gravitropic signaling (A.C. Scott, N.S. Allen [1999] Plant Physiol 121: 1291-1298). The question arises whether pH(c) has a more general role in signaling gravity vector changes. Using confocal ratiometric imaging and the fluorescent pH indicator carboxy seminaphtorhodafluor acetoxymethyl ester acetate, we measured pH(c) in the cells composing the maize pulvinus. When stem slices were gravistimulated and imaged on a horizontally mounted confocal microscope, pH(c) changes were only apparent within the bundle sheath cells, and not in the parenchyma cells. After turning, cytoplasmic acidification was observed at the sides of the cells, whereas the cytoplasm at the base of the cells where plastids slowly accumulated became more basic. These changes were most apparent in cells exhibiting net amyloplast sedimentation. Parenchyma cells and isolated bundle sheath cells did not show any gravity-induced pH(c) changes although all cell types responded to external stimuli in the predicted way: Propionic acid and auxin treatments induced acidification, whereas raising the external pH caused alkalinization. The results suggest that pH(c) has an important role in the early signaling pathways of maize stem gravitropism.

The Efficiency of Noni (Morinda citrifolia L.) Essential Oil on the Control of Leaf Spot Caused by Exserohilum turcicum in Maize Culture.

Science.gov (United States)

Silva, Janaina Costa E; Mourão, Dalmarcia de Sousa Carlos; Lima, Fabia Silva de Oliveira; Sarmento, Renato de Almeida; Dalcin, Mateus Sunti; Aguiar, Raimundo Wagner de Souza; Santos, Gil Rodrigues Dos

2017-08-14

The objective of this work was to evaluate the efficiency of noni essential oil on the control of Exserohilum turcicum , a causative agent of Exserohilum spot in maize culture. In the sanitary test 400 seeds were incubated using the blotter test method. For the transmissibility test, the fragments of damaged leaves of seedlings were removed and put into a potato, dextrose and agar (PDA) culture environment. To verify the pathogenicity, Koch´s postulates were performed. In the phytotoxicity test different concentrations of noni oil were applied in maize seedlings. E. turcicum conidia were submitted to different concentrations of noni oil. In the preventive and curative tests noni essential oils were applied before and after the conidia inoculation, respectively. The results revealed the presence of fungi of the genres Aspergillus , Penicillium , Rhizopus , Fusarium , and Exserohilum in the maize seeds. The pathogenicity of E. turcicum and also the transmission of this fungus from the seeds to the maize seedlings was confirmed. The inhibition of conidia germination was proportional to the concentration increase. The preventive application of noni essential oil was the most efficient on the control of Exserohilum spot.

Maize variety and method of production

Science.gov (United States)

Pauly, Markus; Hake, Sarah; Kraemer, Florian J

2014-05-27

The disclosure relates to a maize plant, seed, variety, and hybrid. More specifically, the disclosure relates to a maize plant containing a Cal-1 allele, whose expression results in increased cell wall-derived glucan content in the maize plant. The disclosure also relates to crossing inbreds, varieties, and hybrids containing the Cal-1 allele to produce novel types and varieties of maize plants.

Transient foreign gene expression in chloroplasts of cultured tobacco cells after biolistic delivery of chloroplast vectors.

Science.gov (United States)

Daniell, H; Vivekananda, J; Nielsen, B L; Ye, G N; Tewari, K K; Sanford, J C

1990-01-01

Expression of chloramphenicol acetyltransferase (cat) by suitable vectors in chloroplasts of cultured tobacco cells, delivered by high-velocity microprojectiles, is reported here. Several chloroplast expression vectors containing bacterial cat genes, placed under the control of either psbA promoter region from pea (pHD series) or rbcL promoter region from maize (pAC series) have been used in this study. In addition, chloroplast expression vectors containing replicon fragments from pea, tobacco, or maize chloroplast DNA have also been tested for efficiency and duration of cat expression in chloroplasts of tobacco cells. Cultured NT1 tobacco cells collected on filter papers were bombarded with tungsten particles coated with pUC118 (negative control), 35S-CAT (nuclear expression vector), pHD312 (repliconless chloroplast expression vector), and pHD407, pACp18, and pACp19 (chloroplast expression vectors with replicon). Sonic extracts of cells bombarded with pUC118 showed no detectable cat activity in the autoradiograms. Nuclear expression of cat reached two-thirds of the maximal 48 hr after bombardment and the maximal at 72 hr. Cells bombarded with chloroplast expression vectors showed a low level of expression until 48 hr of incubation. A dramatic increase in the expression of cat was observed 24 hr after the addition of fresh medium to cultured cells in samples bombarded with pHD407; the repliconless vector pHD312 showed about 50% of this maximal activity. The expression of nuclear cat and the repliconless chloroplast vector decreased after 72 hr, but a high level of chloroplast cat expression was maintained in cells bombarded with pHD407. Organelle-specific expression of cat in appropriate compartments was checked by introducing various plasmid constructions into tobacco protoplasts by electroporation. Although the nuclear expression vector 35S-CAT showed expression of cat, no activity was observed with any chloroplast vectors.

Estimation of N2-fixation in cowpea grown in monoculture or in mixture with maize using 15 N

International Nuclear Information System (INIS)

Shammaa, Mouhammad; Kurd Ali, Fawaz

1994-01-01

A pot experiment was carried out under natural climatic conditions to determine the proportion of different nitrogen sources (air, soil, fertilizer) in cowpea and maize grown alone or in mixture using 15 N isotope dilution technique. On average, the proportion of N derived from fixation by cowpea grown in mixed culture was 55% lower than that derived by the sole cropped cowpea (77%). Dry matter produced by one plant of maize grown in mixed culture was twice as much as that produced by a plant grown in mono culture. Moreover, total nitrogen content in one maize plant grown in mixed culture was 213 mg higher than that determined by two plant of maize grown in mono culture (171 mg). However, the amount of nitrogen derived from soil by maize grown in mixed culture was equal or even higher than that taken up by two plants of maize grown in mono culture. This indicates a better utilization of soil N by the maize in mixed culture. This data emphasize the crucial role of interspecific competition in soil N uptake. Data from this study do not support the hypothesis of N transfer from the legume to the cereal because no significant differences were found between mixed and pure maize in terms of 15 N in excess content. (author). 9 refs., 1 tab

Mixing of maize and wheat genomic DNA by somatic hybridization in regenerated sterile maize plants.

Science.gov (United States)

Szarka, B.; Göntér, I.; Molnár-Láng, M.; Mórocz, S.; Dudits, D.

2002-07-01

Intergeneric somatic hybridization was performed between albino maize ( Zea mays L.) protoplasts and mesophyll protoplasts of wheat ( Triticum aestivum L.) by polyethylene glycol (PEG) treatments. None of the parental protoplasts were able to produce green plants without fusion. The maize cells regenerated only rudimentary albino plantlets of limited viability, and the wheat mesophyll protoplasts were unable to divide. PEG-mediated fusion treatments resulted in hybrid cells with mixed cytoplasm. Six months after fusion green embryogenic calli were selected as putative hybrids. The first-regenerates were discovered as aborted embryos. Regeneration of intact, green, maize-like plants needed 6 months of further subcultures on hormone-free medium. These plants were sterile, although had both male and female flowers. The cytological analysis of cells from callus tissues and root tips revealed 56 chromosomes, but intact wheat chromosomes were not observed. Using total DNA from hybrid plants, three RAPD primer combinations produced bands resembling the wheat profile. Genomic in situ hybridization (GISH) using total wheat DNA as a probe revealed the presence of wheat DNA islands in the maize chromosomal background. The increased viability and the restored green color were the most-significant new traits as compared to the original maize parent. Other intermediate morphological traits of plants with hybrid origin were not found.

Study on the in vitro culture of cut plants in wheat haploid embryo induction by a wheat × maize cross

Institute of Scientific and Technical Information of China (English)

Jian GU; Kun LIU; Shaoxiang LI; Yuxian TIAN; Hexian YANG; Mujun YANG

2008-01-01

The wheat × maize system is one of the most effective ways to produce haploids in wheat. Whether and how it could be successfully applied in practical breeding mostly depends upon the efficiency of haploid embryo pro-duction. To perfect the protocols of haploid embryo induc-tion, the efficiency of haploid embryo production between in vitro culture of cut plant and intact plant growth for hybrid spikes with two F1 wheat hybrids and two maize varieties was compared. Effects of different cutting plant times and formulas of nutrient solutions for cut plant cul-ture on haploid embryo formation were also studied. Results indicated that the embryo rate of in vitro culture was 3.29 times that of intact plant growth, with the figures of 31.6% vs 9.6%, respectively. The optimal time for cut plant culture was 24 h after pollination. Formulas of nutri-ent solutions significantly affected the efficiency of haploid embryo induction. With an embryo rate of 0-35.5%, add-could raise the caryopsis and embryo rates. According to this study, the best medium for cut plant culture was: phate, with which a caryopsis rate of 95% and an embryo rate of about 30% could be obtained.

Occurrence of toxigenic fungi in maize and maize-gluten meal from Pakistan

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Muhammad Kashif SALEEMI

2012-05-01

Full Text Available The present study was designed to isolate and identify toxigenic mycoflora of maize and maize-gluten meal. A total of 82 samples of maize and 8 samples of maize-gluten meal were collected from Faisalabad district of Pakistan over a period of two years. These samples were inoculated on different culture media. Fungal contamination of maize and maize-gluten was 56% and 75% of samples, respectively. Isolation frequencies of different genera isolated from maize were Aspergillus 33%; Penicillium 28%; Fusarium 10%; and Alternaria 1%. Isolation frequency among species was maximum for P. verrucosum, followed by A. niger aggregates, A. ochraceous, A. flavus, P. chrysogenum, A. parasiticus, A. carbonarius, Fusarium spp. and Alternaria spp. Relative density of Aspergillus isolates was maximum for A. niger aggregates and A. ochraceous (30% each followed by A. flavus (26%, A. parasiticus (11% and A. carbonarius (3%. Percentage of toxigenic fungi among Aspergillus isolates was 52%. Aflatoxigenic isolates of A. flavus and A. parasiticus were 43 and 67% and ochratoxigenic isolates of A. carbonarius, A. ochraceous and A. niger aggregates were 100, 63 and 38%, respectively. Aspergillus parasiticus produced higher concentrations of AFB1 (maximum 1374.23 ng g-1 than A. flavus (maximum 635.50 ng g-1. Ochratoxin A production potential of A. ochraceous ranged from 1.81 to 9523.1 ng g-1, while in A. niger aggregates it was 1.30 to 1758.6 ng g-1. Isolation frequencies of fungal genera from maize-gluten meal were Aspergillus (63% and Penicillium (50%. A. flavus was the most frequently isolated species. Percentage of toxigenic fungi among Aspergillus isolates was 40%. Aflatoxigenic isolates of A. flavus were 33% and ochratoxigenic isolates of A. ochraceous were 100%.

Sugar transport by maize endosperm suspension cultures

International Nuclear Information System (INIS)

Felker, F.C.; Goodwin, J.C.

1987-01-01

To determine the mechanism of sugar uptake by suspension cultures derived from developing maize (Zea mays L.) endosperm, incorporation of radioactivity from 14 C-sugars by the tissue in the mid-log phase of growth was examined. Among the sugars tested was l'-deoxy-l'-fluorosucrose (FS), a derivative not hydrolyzed by invertase but recognized by sucrose carriers in other systems. At 40 mM, uptake of label from FS was 23% of that from sucrose, while uptake of label from L-glucose (used as a control for medium carry-over and adsorption) was 16% of that from sucrose. Uptake of label from sucrose did not increase at concentrations above 50 mM, possibly due to a rate-limiting requirement for extracellular hydrolysis. Kinetic analysis revealed both saturable and linear components of uptake for glucose and fructose. The rate of fructose uptake exceeded that of glucose at all concentrations. Fructose uptake at 20 mM was inhibited by NaN 3 , HgCl 2 , dinitrophenol, carbonyl cyanide m-chlorophenylhydrazone, and p-chloromercuribenzenesulfonic acid. Results suggest that sucrose is hydrolyzed prior to uptake, and that fructose is transported preferentially by a carrier sensitive to an external sulfhydryl group inhibitor. Metabolic activity is required for sugar uptake. The specificity of the hexose transporter is currently being investigated

SEED INOCULATION WITH Azospirillum brasilense, ASSOCIATED WITH THE USE OF BIOREGULATORS IN MAIZE

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ALESSANDRO DE LUCCA E BRACCINI

2012-01-01

Full Text Available The inoculation of seeds with the bacterium Azospirillum has been carried out in maize culture and other grasses. The application of growth bio-regulators is another technology whose results in maize culture have yet to become more widespread. Current study evaluates the agronomic effectiveness of seed inoculation with Azospirillum brasilense in maize, associated with the use of the growth regulator Stimulate ®. Triple hybrid maize CD 304 underwent the following treatments: 1 - control without nitrogen and without Azospirillum brasilense; 2 - Treatment without nitrogen but with Azospirillum brasilense; 3 - Treatment without nitrogen but with Azospirillum brasilense + Stimulate ®; 4 - Treatment with 50% of nitrogen dose recommended for maize culture; 5 - Treatment with 50% of nitrogen dose and inoculation with Azospirillum brasilense; 6 - Same as 5 but with Stimulate ®; 7 - Total N recommended; 8 - Total N recommended + Azospirillum brasilense ; 9 - Total N recommended + Azospirillum brasilense + Stimulate ®. The inoculation of maize seeds with Azospirillum brasilense increases plant height and grain yield when compared with rates in control. The use of 50% of N dose in sowing, associated with the inoculation of maize seeds with Azospirillum brasilense at 200 mL ha-1 (mixed to the seeds and associated with Stimulate ® (in foliar application, is viable.

Participation of cob tissue in the transport of medium components into maize kernels cultured in vitro

International Nuclear Information System (INIS)

Felker, F.C.

1990-01-01

Maize (Zea mays L.) kernels cultured in vitro while still attached to cob pieces have been used as a model system to study the physiology of kernel development. In this study, the role of the cob tissue in uptake of medium components into kernels was examined. Cob tissue was essential for in vitro kernel growth, and better growth occurred with larger cob/kernel ratios. A symplastically transported fluorescent dye readily permeated the endosperm when supplied in the medium, while an apoplastic dye did not. Slicing the cob tissue to disrupt vascular connections, but not apoplastic continuity, greatly reduced [ 14 C]sucrose uptake into kernels. [ 14 C]Sucrose uptake by cob and kernel tissue was reduced 31% and 68%, respectively, by 5 mM PCMBS. L-[ 14 C]glucose was absorbed much more slowly than D-[ 14 C]glucose. These and other results indicate that phloem loading of sugars occurs in the cob tissue. Passage of medium components through the symplast cob tissue may be a prerequisite for uptake into the kernel. Simple diffusion from the medium to the kernels is unlikely. Therefore, the ability of substances to be transported into cob tissue cells should be considered in formulating culture medium

Transient foreign gene expression in chloroplasts of cultured tobacco cells after biolistic delivery of chloroplast vectors.

OpenAIRE

Daniell, H; Vivekananda, J; Nielsen, B L; Ye, G N; Tewari, K K; Sanford, J C

1990-01-01

Expression of chloramphenicol acetyltransferase (cat) by suitable vectors in chloroplasts of cultured tobacco cells, delivered by high-velocity microprojectiles, is reported here. Several chloroplast expression vectors containing bacterial cat genes, placed under the control of either psbA promoter region from pea (pHD series) or rbcL promoter region from maize (pAC series) have been used in this study. In addition, chloroplast expression vectors containing replicon fragments from pea, tobacc...

Clonal analysis of the cell lineages in the male flower of maize

International Nuclear Information System (INIS)

Dawe, R.K.; Freeling, M.

1990-01-01

The cell lineages in the male flower of maize were characterized using X-rays and transposable elements to produce clonal sectors differing in anthocyanin pigmentation. Less than 50% of the somatic tassel mutations (caused by reversion of unstable color mutations) that were visible on the anther wall were sexually transmitted by the male gametes, unless the sectors were larger than half the tassel circumference. This result is explained by showing that: (a) both the outer (LI) and inner (LII) lineages of the shoot apical meristem form a cell layer in the bilayered anther wall, and that anther pigmentation can be derived from either cell layer; and that (b) the male germ cells are derived almost exclusively from the LII. Therefore, while reversion events in either the LI or LII are visible on the anther, only the LII events are heritable. Reversion events that occur prior to the organization of the shoot apical meristem however, produce large (usually more than one-half tassel) sectors that include both the outer and inner lineages. In contrast to the high level of cell layer invasion previously reported during leaf development, during anther development less than 10(-3) cells in the LI invade the LII to form male gametes. The strong correlation between cell lineage and cell fate in the maize anther has implications for studies on plant evolution and the genetic improvement of cereals by DNA transformation

Onset of cell division in maize germination: action of auxins

International Nuclear Information System (INIS)

de Jimenez, E.S.; Baiza, A.; Aguilar, R.

1987-01-01

Seed germination implies metabolic reactivation, synthesis of macromolecules and onset of cell division. During maize germination, meristematic tissues of embryos re-initiate cell division asynchronically. Since auxins are known to stimulate cell division, they asked how auxins might regulate cell cycle re-initiation. Embryonic tissues were incubated with and without auxins. A pulse of either 3 H-thymidine or 32 P-ortophosphate was given to the tissues. Mitotic indexes were determined and % of labeled mitotic cells recorded. Results indicated that meristematic cells re-initiate cell division either from G 1 or G 2 phases. Auxin stimulated differentially the cell division process of these cells. 32 P incorporation into cytoplasmic or nucleic histones was measured. Auxins stimulated this incorporation. Active turnover of histone phosphorylation occurred simultaneously to the cell division process. It is suggested that auxins might regulate the cell cycle by phosphorylation-dephosphorylation of histones

Genetic Factors Involved in Fumonisin Accumulation in Maize Kernels and Their Implications in Maize Agronomic Management and Breeding.

Science.gov (United States)

Santiago, Rogelio; Cao, Ana; Butrón, Ana

2015-08-20

Contamination of maize with fumonisins depends on the environmental conditions; the maize resistance to contamination and the interaction between both factors. Although the effect of environmental factors is a determinant for establishing the risk of kernel contamination in a region, there is sufficient genetic variability among maize to develop resistance to fumonisin contamination and to breed varieties with contamination at safe levels. In addition, ascertaining which environmental factors are the most important in a region will allow the implementation of risk monitoring programs and suitable cultural practices to reduce the impact of such environmental variables. The current paper reviews all works done to address the influence of environmental variables on fumonisin accumulation, the genetics of maize resistance to fumonisin accumulation, and the search for the biochemical and/or structural mechanisms of the maize plant that could be involved in resistance to fumonisin contamination. We also explore the outcomes of breeding programs and risk monitoring of undertaken projects.

Fermentation characteristics of polysaccharide fractions extracted from the cell walls of maize endosperm

NARCIS (Netherlands)

Laar, van H.; Tamminga, S.; Williams, B.A.; Verstegen, M.W.A.; Schols, H.A.

2002-01-01

Cell walls were extracted from maize endosperm and separated into different polysaccharide fractions by sequential extraction with solutions of saturated Ba(OH)2, demineralised water and 1 and 4 M KOH. Solubilised polysaccharides were collected after each extraction. Residues were collected

Dissolution of different zinc salts and zn uptake by Sedum alfredii and maize in mono- and co-cropping under hydroponic culture.

Science.gov (United States)

Jiang, Cheng'ai; Wu, Qitang; Zeng, Shucai; Chen, Xian; Wei, Zebin; Long, Xinxian

2013-09-01

Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono- and co-cropped (without a root barrier) in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3(PO4)2 and 5ZnO x 2CO3-4H2O (represented as ZnCO3) at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210-2603 mg/kg for maize shoots and 6445-12476 mg/kg for S. alfredii in the same order: ZnCO3 > ZnO > Zn3(PO4)2 > ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2+ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids (LMWOA) and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii.

Complete disintegration of the microtubular cytoskeleton precedes its auxin-mediated reconstruction in postmitotic maize root cells

Science.gov (United States)

Baluska, F.; Barlow, P. W.; Volkmann, D.

1996-01-01

The inhibitory action of 0.1 microM auxin (IAA) on maize root growth was closely associated with a rapid and complete disintegration of the microtubular (MT) cytoskeleton, as visualized by indirect immunofluorescence of tubulin, throughout the growth region. After 30 min of this treatment, only fluorescent spots were present in root cells, accumulating either around nuclei or along cell walls. Six h later, in addition to some background fluorescence, dense but partially oriented oblique or longitudinal arrays of cortical MTs (CMTs) were found in most growing cells of the root apex. After 24 h of treatment, maize roots had adapted to the auxin, as inferred from the slowly recovering elongation rate and from the reassembly of a dense and well-ordered MT cytoskeleton which showed only slight deviations from that of the control root cells. Taxol pretreatment (100 microM, 24 h) prevented not only the rapid auxin-mediated disintegration of the MT cytoskeleton but also a reorientation of the CMT arrays, from transversal to longitudinal. The only tissue to show MTs in their cells throughout the auxin treatment was the epidermis. Significant resistance of transverse CMT arrays in these cells towards auxin was confirmed using a higher auxin concentration (100 microM, 24 h). The latter auxin dose also revealed inter-tissue-specific responses to auxin: outer cortical cell files reoriented their CMTs from the transversal to longitudinal orientation, whereas inner cortical cell files lost their MTs. This high auxin-mediated response, associated with the swelling of root apices, was abolished with the pretreatment of maize root with taxol.

Maize Inoculation with Azospirillum brasilense Ab-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input

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André L. M. Oliveira

2017-09-01

Full Text Available Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS and polyhydroxybutirate (PHB was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in

Maize Inoculation with Azospirillum brasilense Ab-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input

Science.gov (United States)

Oliveira, André L. M.; Santos, Odair J. A. P.; Marcelino, Paulo R. F.; Milani, Karina M. L.; Zuluaga, Mónica Y. A.; Zucareli, Claudemir; Gonçalves, Leandro S. A.

2017-01-01

Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS) and polyhydroxybutirate (PHB) was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in N fertilizer

Control of cell proliferation, endoreduplication, cell size, and cell death by the retinoblastoma-related pathway in maize endosperm

KAUST Repository

Sabelli, Paolo A.

2013-04-22

The endospermof cereal grains is one of the most valuable products of modern agriculture. Cereal endosperm development comprises different phases characterized by mitotic cell proliferation, endoreduplication, the accumulation of storage compounds, and programmed cell death. Although manipulation of these processes could maximize grain yield, how they are regulated and integrated is poorly understood. We show that the Retinoblastoma-related (RBR) pathway controls key aspects of endosperm development in maize. Down-regulation of RBR1 by RNAi resulted in up-regulation of RBR3-type genes, as well as the MINICHROMOSOME MAINTENANCE 2-7 gene family and PROLIFERATING CELL NUCLEAR ANTIGEN, which encode essential DNA replication factors. Both the mitotic and endoreduplication cell cycles were stimulated. Developing transgenic endosperm contained 42-58% more cells and ~70% more DNA than wild type, whereas there was a reduction in cell and nuclear sizes. In addition, cell death was enhanced. The DNA content of mature endosperm increased 43% upon RBR1 downregulation, whereas storage protein content and kernel weight were essentially not affected. Down-regulation of both RBR1 and CYCLIN DEPENDENT KINASE A (CDKA);1 indicated that CDKA;1 is epistatic to RBR1 and controls endoreduplication through an RBR1- dependent pathway. However, the repressive activity of RBR1 on downstream targets was independent from CDKA;1, suggesting diversification of RBR1 activities. Furthermore, RBR1 negatively regulated CDK activity, suggesting the presence of a feedback loop. These results indicate that the RBR1 pathway plays a major role in regulation of different processes during maize endosperm development and suggest the presence of tissue/organlevel regulation of endosperm/seed homeostasis.

Regeneration of Sudanese maize inbred lines and open pollinated ...

African Journals Online (AJOL)

STORAGESEVER

2008-06-03

Jun 3, 2008 ... Keywords: Sudanese maize genotypes, embryogenic callus, regeneration, and tissue culture. INTRODUCTION. Maize is an important food and forage crop in the North- ern and Southern regions of ... Skoog, 1965) containing 60 g l-1 sucrose and lacking 2,4-D (referred to as maturation or RI medium) and ...

Regeneration of tropical maize lines ( Zea mays l .) from mature ...

African Journals Online (AJOL)

The use of immature zygotic embryos as an explant for maize regeneration has been hampered by the strictly limited suitable duration of immature embryos for culture. In contrast, mature zygotic embryos harvested from dry seeds are ubiquitous. However, generally mature embryos and especially tropical maize genotypes ...

Auxins differentially regulate root system architecture and cell cycle protein levels in maize seedlings.

Science.gov (United States)

Martínez-de la Cruz, Enrique; García-Ramírez, Elpidio; Vázquez-Ramos, Jorge M; Reyes de la Cruz, Homero; López-Bucio, José

2015-03-15

Maize (Zea mays) root system architecture has a complex organization, with adventitious and lateral roots determining its overall absorptive capacity. To generate basic information about the earlier stages of root development, we compared the post-embryonic growth of maize seedlings germinated in water-embedded cotton beds with that of plants obtained from embryonic axes cultivated in liquid medium. In addition, the effect of four different auxins, namely indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and 2,4-dichlorophenoxyacetic acid (2,4-D) on root architecture and levels of the heat shock protein HSP101 and the cell cycle proteins CKS1, CYCA1 and CDKA1 were analyzed. Our data show that during the first days after germination, maize seedlings develop several root types with a simultaneous and/or continuous growth. The post-embryonic root development started with the formation of the primary root (PR) and seminal scutellar roots (SSR) and then continued with the formation of adventitious crown roots (CR), brace roots (BR) and lateral roots (LR). Auxins affected root architecture in a dose-response fashion; whereas NAA and IBA mostly stimulated crown root formation, 2,4-D showed a strong repressing effect on growth. The levels of HSP101, CKS1, CYCA1 and CDKA in root and leaf tissues were differentially affected by auxins and interestingly, HSP101 registered an auxin-inducible and root specific expression pattern. Taken together, our results show the timing of early branching patterns of maize and indicate that auxins regulate root development likely through modulation of the HSP101 and cell cycle proteins. Copyright © 2014 Elsevier GmbH. All rights reserved.

Using the filter paper bridge technique for initiation of vitrocultures at maize

Directory of Open Access Journals (Sweden)

Cristian Felix BLIDAR

2012-05-01

Full Text Available Alongside wheat, maize is one of the most important species of cereals used for food and feed as well as in the bioethanol industry. As a result of this fact, maize is today the spotlight of many researchers, constantly trying to increase the productivity of this species, particularly important i from the economic point of view. The main aim of this article is to investigate the efficiency of the Blidar type filter-paper bridges (BFPB in initiating the maize in vitro cultures for liquid culture media, in comparison with the conventional agarized culture media – solid culture media. In these experiments a modified Murashige-Skoog culture media (1962 (free of AIA and amino acids supplemented or not with agar, were used. The inocula consisted in caryopsis of Zea mays L. (hybrid Kiskun 4255 and based on the results of these experiments it can be underlined that growth increases for the cultivated vitroplants on liquid culture media provided with filter-paper bridges compared with those conventianlly cultivated on an agarized culture media, as following 5.34% for dry weight and 356.09% for leafs length.

Insect Cell Culture

NARCIS (Netherlands)

Oers, van M.M.; Lynn, D.E.

2010-01-01

Insect cell cultures are widely used in studies on insect cell physiology, developmental biology and microbial pathology. In particular, insect cell culture is an indispensable tool for the study of insect viruses. The first continuously growing insect cell cultures were established from

Evidence for an evolutionarily conserved interaction between cell wall biosynthesis and flowering in maize and sorghum

Directory of Open Access Journals (Sweden)

Thompson Karen J

2002-01-01

Full Text Available Abstract Background Factors that affect flowering vary among different plant species, and in the grasses in particular the exact mechanism behind this transition is not fully understood. The brown midrib (bm mutants of maize (Zea mays L., which have altered cell wall composition, have different flowering dynamics compared to their wild-type counterparts. This is indicative of a link between cell wall biogenesis and flowering. In order to test whether this relationship also exists in other grasses, the flowering dynamics in sorghum (Sorghum bicolor (L. Moench were investigated. Sorghum is evolutionarily closely related to maize, and a set of brown midrib (bmr mutants similar to the maize bm mutants is available, making sorghum a suitable choice for study in this context. Results We compared the flowering time (time to half-bloom of several different bmr sorghum lines and their wild-type counterparts. This revealed that the relationship between cell wall composition and flowering was conserved in sorghum. Specifically, the mutant bmr7 flowered significantly earlier than the corresponding wild-type control, whereas the mutants bmr2, bmr4, bmr6, bmr12, and bmr19 flowered later than their wild-type controls. Conclusion The change in flowering dynamics in several of the brown midrib sorghum lines provides evidence for an evolutionarily conserved mechanism that links cell wall biosynthesis to flowering dynamics. The availability of the sorghum bmr mutants expands the germplasm available to investigate this relationship in further detail.

Behavior of some micro-organisms cultivated in the presence of extracts of irradiated maize starch

International Nuclear Information System (INIS)

Mucchielli, Alain; Fretton, Robert; Saint-Lebe, Louis

1977-01-01

The bactericidal effect of water soluble radiolysis products of Maize starch on Escherichia coli cultures declines when the initial population grows. This toxicity varies with the culture environment and the bacterial species: Bacillus subtilis, Lactobacillus plantarum, Streptococcus faecalis, Enterobacter sp. Moreover, for the eucaryote cell Saccharomyces cerevisiae, wild strain or muting 'small colonies', only the generating time is altered by the active parts of radiolysis products. The results are analysed with regard to the hypothesis that the hydrogen peroxide is responsible for this toxicity [fr

Metabolism of 14C-bentazone in wheat, oat, and maize

International Nuclear Information System (INIS)

Mueller, F.; Sanad, A.

1975-01-01

The uptake, distribution, and catabolism of Bentazon (3-isopropyl-2,1,3-benzo-thiadiazinon-(4)-2,2-dioxide) in winter wheat (variety Jubilar), maize (variety Inra 258), and several varieties of oat was investigated in the hothouse and under outside conditions in large culture vessels. Bentazon is decomposed fairly rapidly in wheat, maize, and oat. In the experiments with cultures in vessels under outside conditions, the metabolic fate of the 14 C-labelled pesticide was investigated in three varieties of oat after a vegetation period. (GSE/AK) [de

Exploring the Bacterial Microbiota of Colombian Fermented Maize Dough "Masa Agria" (Maiz Añejo).

Science.gov (United States)

Chaves-Lopez, Clemencia; Serio, Annalisa; Delgado-Ospina, Johannes; Rossi, Chiara; Grande-Tovar, Carlos D; Paparella, Antonello

2016-01-01

Masa Agria is a naturally fermented maize dough produced in Colombia, very common in the traditional gastronomy. In this study we used culture-dependent and RNA-based pyrosequencing to investigate the bacterial community structure of Masa Agria samples produced in the south west of Colombia. The mean value of cell density was 7.6 log CFU/g of presumptive lactic acid bacteria, 5.4 log cfu/g for presumptive acetic bacteria and 5.6 og CFU/g for yeasts. The abundance of these microorganisms is also responsible for the low pH (3.1-3.7) registered. Although the 16S rRNA pyrosequencing revealed that the analyzed samples were different in bacteria richness and diversity, the genera Lactobacillus, Weissella, and Acetobacter were predominant. In particular, the most common species were Lactobacillus plantarum and Acetobacter fabarum, followed by L. fermentum, L. vaccinostercus, and Pediococcus argentinicus. Several microorganisms of environmental origin, such as Dechloromonas and most of all Sphingobium spp., revealed in each sample, were detected, and also bacteria related to maize, such as Phytoplasma. In conclusion, our results elucidated for the first time the structures of the bacterial communities of Masa Agria samples obtained from different producers, identifying the specific dominant species and revealing a complete picture of the bacterial consortium in this specific niche. The selective pressure of tropical environments may favor microbial biodiversity characterized by a useful technological potential.

Soya beans and maize : the effect of chemical and physical structure of cell wall polysaccharides on fermentation kinetics

NARCIS (Netherlands)

Laar, van H.

2000-01-01

The analysis of the relationship between cell wall composition and fermentation of endosperm cell walls of soya beans and maize was approached from three different angles. Firstly, the fermentation (rate and extent of fermentation, the sugar degradation pattern, and volatile fatty acid

Post-Transcriptional Regulation Prevents Accumulation of Glutathione Reductase Protein and Activity in the Bundle Sheath Cells of Maize1

Science.gov (United States)

Pastori, Gabriela M.; Mullineaux, Philip M.; Foyer, Christine H.

2000-01-01

Glutathione reductase (GR; EC 1.6.4.2) activity was assayed in bundle sheath and mesophyll cells of maize (Zea mays L. var H99) from plants grown at 20°C, 18°C, and 15°C. The purity of each fraction was determined by measuring the associated activity of the compartment-specific marker enzymes, Rubisco and phosphoenolpyruvate carboxylase, respectively. GR activity and the abundance of GR protein and mRNA increased in plants grown at 15°C and 18°C compared with those grown at 20°C. In all cases GR activity was found only in mesophyll fractions of the leaves, with no GR activity being detectable in bundle sheath extracts. Immunogold labeling with GR-specific antibodies showed that the GR protein was exclusively localized in the mesophyll cells of leaves at all growth temperatures, whereas GR transcripts (as determined by in situ hybridization techniques) were observed in both cell types. These results indicate that post-transcriptional regulation prevents GR accumulation in the bundle sheath cells of maize leaves. The resulting limitation on the capacity for regeneration of reduced glutathione in this compartment may contribute to the extreme chilling sensitivity of maize leaves. PMID:10712529

Aflatoxins and fumonisin contamination of marketed maize, maize ...

African Journals Online (AJOL)

Aflatoxins and fumonisin contamination of marketed maize, maize bran and maize used as animal feed in northern ... PROMOTING ACCESS TO AFRICAN RESEARCH ... African Journal of Food, Agriculture, Nutrition and Development.

Tracking maize pollen development by the Leaf Collar Method.

Science.gov (United States)

Begcy, Kevin; Dresselhaus, Thomas

2017-12-01

An easy and highly reproducible nondestructive method named the Leaf Collar Method is described to identify and characterize the different stages of pollen development in maize. In plants, many cellular events such as meiosis, asymmetric cell division, cell cycle regulation, cell fate determination, nucleus movement, vacuole formation, chromatin condensation and epigenetic modifications take place during pollen development. In maize, pollen development occurs in tassels that are confined within the internal stalk of the plant. Hence, identification of the different pollen developmental stages as a tool to investigate above biological processes is impossible without dissecting the entire plant. Therefore, an efficient and reproducible method is necessary to isolate homogeneous cell populations at individual stages throughout pollen development without destroying the plant. Here, we describe a method to identify the various stages of pollen development in maize. Using the Leaf Collar Method in the maize inbreed line B73, we have determined the duration of each stage from pollen mother cells before meiosis to mature tricellular pollen. Anther and tassel size as well as percentage of pollen stages were correlated with vegetative stages, which are easily recognized. The identification of stage-specific genes indicates the reproducibility of the method. In summary, we present an easy and highly reproducible nondestructive method to identify and characterize the different stages of pollen development in maize. This method now opens the way for many subsequent physiological, morphological and molecular analyses to study, for instance, transcriptomics, metabolomics, DNA methylation and chromatin patterns during normal and stressful conditions throughout pollen development in one of the economically most important grass species.

Chemical and nutritional values of maize and maize products ...

African Journals Online (AJOL)

Maize and maize products in selected grain markets within Kaduna, Nigeria, were obtained and investigated for proximate and mineral composition analysis using Atomic Absorption Spectrophotometer (AAS) and flame photometer. Proximate composition of maize and maize products were in the range of 11.6- 20 .0% ...

Pathogen Trojan Horse Delivers Bioactive Host Protein to Alter Maize Anther Cell Behavior in Situ.

Science.gov (United States)

van der Linde, Karina; Timofejeva, Ljudmilla; Egger, Rachel L; Ilau, Birger; Hammond, Reza; Teng, Chong; Meyers, Blake C; Doehlemann, Gunther; Walbot, Virginia

2018-03-01

Small proteins are crucial signals during development, host defense, and physiology. The highly spatiotemporal restricted functions of signaling proteins remain challenging to study in planta. The several month span required to assess transgene expression, particularly in flowers, combined with the uncertainties from transgene position effects and ubiquitous or overexpression, makes monitoring of spatiotemporally restricted signaling proteins lengthy and difficult. This situation could be rectified with a transient assay in which protein deployment is tightly controlled spatially and temporally in planta to assess protein functions, timing, and cellular targets as well as to facilitate rapid mutagenesis to define functional protein domains. In maize ( Zea mays ), secreted ZmMAC1 (MULTIPLE ARCHESPORIAL CELLS1) was proposed to trigger somatic niche formation during anther development by participating in a ligand-receptor module. Inspired by Homer's Trojan horse myth, we engineered a protein delivery system that exploits the secretory capabilities of the maize smut fungus Ustilago maydis , to allow protein delivery to individual cells in certain cell layers at precise time points. Pathogen-supplied ZmMAC1 cell-autonomously corrected both somatic cell division and differentiation defects in mutant Zm mac1-1 anthers. These results suggest that exploiting host-pathogen interactions may become a generally useful method for targeting host proteins to cell and tissue types to clarify cellular autonomy and to analyze steps in cell responses. © 2018 American Society of Plant Biologists. All rights reserved.

The effect of gamma radiation and N-ethyl-N-nitrosourea on cultured maize callus growth and plant regeneration

International Nuclear Information System (INIS)

Moustafa, R.A.K.; Duncan, D.R.; Widholm, J.M.

1989-01-01

Regenerable maize calli of two inbred lines were exposed to 0 to 100 Gy of gamma rays or treated with 0 to 30 mM of N-ethyl-N-nitrosourea (ENU) to determine their effect on growth and plant regeneration capability. Both growth and plant regeneration capacity decreased with increasing levels of either gamma radiation or ENU; however, plant regeneration capacity was more sensitive to either agent than growth. The 50% inhibition dose (I 50 ) for callus growth (fresh-weight gain) was approximately 100 Gy of gamma radiation and 30 mM ENU. The I 50 for plant regeneration capacity of treated callus was approximately 25 Gy of gamma radiation and 2.5 mM ENU. The decrease in plant regeneration capacity correlated with a change in tissue composition of the treated callus from a hard, yellow and opaque tissue to a soft, grayish-yellow and translucent tissue. This change was quantified by measuring the reduction of MnO 4 - to MnO 2 (PR assay) by the callus. These results suggest that the effect of gamma radiation or ENU on plant regeneration capacity must be taken into consideration if these potentially mutagenic agents are to be used on maize callus cultures, for the purpose of producing useful mutations at a whole plant level. The data also suggest that the PR assay may be useful for predicting the actual plant regeneration capacity of maize callus. (author)

The Maize MID-COMPLEMENTING ACTIVITY homolog CELL NUMBER REGULATOR13/NARROW ODD DWARF, coordinates organ growth and tissue patterning

Science.gov (United States)

Organogenesis occurs from cell division, expansion and differentiation. How these cellular processes are coordinated remains elusive. The maize leaf provides an excellent system to study cellular differentiation because it has several different tissues and cell types. The narrow odd dwarf (nod) mut...

Increasing cell culture population doublings for long-term growth of finite life span human cell cultures

Science.gov (United States)

Stampfer, Martha R; Garbe, James C

2015-02-24

Cell culture media formulations for culturing human epithelial cells are herein described. Also described are methods of increasing population doublings in a cell culture of finite life span human epithelial cells and prolonging the life span of human cell cultures. Using the cell culture media disclosed alone and in combination with addition to the cell culture of a compound associated with anti-stress activity achieves extended growth of pre-stasis cells and increased population doublings and life span in human epithelial cell cultures.

Proteomics of Maize Root Development.

Science.gov (United States)

Hochholdinger, Frank; Marcon, Caroline; Baldauf, Jutta A; Yu, Peng; Frey, Felix P

2018-01-01

Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.

Proteomics of Maize Root Development

Directory of Open Access Journals (Sweden)

Frank Hochholdinger

2018-03-01

Full Text Available Maize forms a complex root system with structurally and functionally diverse root types that are formed at different developmental stages to extract water and mineral nutrients from soil. In recent years proteomics has been intensively applied to identify proteins involved in shaping the three-dimensional architecture and regulating the function of the maize root system. With the help of developmental mutants, proteomic changes during the initiation and emergence of shoot-borne, lateral and seminal roots have been examined. Furthermore, root hairs were surveyed to understand the proteomic changes during the elongation of these single cell type structures. In addition, primary roots have been used to study developmental changes of the proteome but also to investigate the proteomes of distinct tissues such as the meristematic zone, the elongation zone as well as stele and cortex of the differentiation zone. Moreover, subcellular fractions of the primary root including cell walls, plasma membranes and secreted mucilage have been analyzed. Finally, the superior vigor of hybrid seedling roots compared to their parental inbred lines was studied on the proteome level. In summary, these studies provide novel insights into the complex proteomic interactions of the elaborate maize root system during development.

Resistance of maize varieties to the maize weevil Sitophilus zeamais

African Journals Online (AJOL)

This study aimed at evaluating commonly used maize varieties, collected from Melkasa and Bako Agricultural Research Centers and Haramaya University, Ethiopia, against the maize weevil Sitophilus zeamais Motsch., one of the most important cosmopolitan stored product pests in maize. A total of 13 improved maize ...

Intercropping Maize With Legumes for Sustainable Highland Maize Production

Directory of Open Access Journals (Sweden)

Adirek Punyalue

2018-02-01

Full Text Available Residue burning to prepare soil for maize growing deprives the soil of both protective cover and organic matter, and it exacerbates environmental issues such as Southeast Asia's haze problem. This paper reports on a study that evaluated the effectiveness of maize/legume intercropping as an alternative to maize cultivation with residue burning. Cowpea (Vigna unguiculata, mung bean (V. radiata, rice bean (V. umbellata, and lablab (Lablab purpureus were sown into a standing maize crop 30 days before harvest, and the results were compared with a maize crop grown using residue burning as the method for land preparation at Pang Da Agricultural Station in Chiang Mai, Thailand, in a replicated trial conducted over 3 growing seasons from 2012 to 2014. Intercropping increased maize grain yield by 31–53% and left 70–170% more residue containing 113–230% more nitrogen than the maize sown after residue burning, depending on the legume, and decreased weed dry weight by two-thirds after 2 seasons. Soil biodiversity was enriched by the intercrops, with a doubling in the spore density of arbuscular mycorrhizal fungi in the root-zone soil and increased abundance, diversity (Shannon index, and richness of the soil macrofauna. The abundance of soil animals increased with crop residue dry weight (r = 0.90, P < 0.05 and nitrogen content (r = 0.98, P < 0.01. The effect of intercropping on maize grain yield and accumulation of residue and nitrogen were then confirmed in a participatory experiment involving farmers in 2 highland villages in the Phrao and Chiang Dao districts of Chiang Mai Province with maize and rice bean in 2015. The effects of maize/legume intercropping—increased nitrogen accumulation and crop residue, enhanced soil biodiversity, suppression of weeds, and protection of the soil surface, which enabled the maize to be sown without land clearing with fire—should all contribute to sustainable highland maize production.

Phylloplane bacteria of Jatropha curcas: diversity, metabolic characteristics, and growth-promoting attributes towards vigor of maize seedling.

Science.gov (United States)

Dubey, Garima; Kollah, Bharati; Ahirwar, Usha; Mandal, Asit; Thakur, Jyoti Kumar; Patra, Ashok Kumar; Mohanty, Santosh Ranjan

2017-10-01

The complex role of phylloplane microorganisms is less understood than that of rhizospheric microorganisms in lieu of their pivotal role in plant's sustainability. This experiment aims to study the diversity of the culturable phylloplane bacteria of Jatropha curcas and evaluate their growth-promoting activities towards maize seedling vigor. Heterotrophic bacteria were isolated from the phylloplane of J. curcas and their 16S rRNA genes were sequenced. Sequences of the 16S rRNA gene were very similar to those of species belonging to the classes Bacillales (50%), Gammaproteobacteria (21.8%), Betaproteobacteria (15.6%), and Alphaproteobacteria (12.5%). The phylloplane bacteria preferred to utilize alcohol rather than monosaccharides and polysaccharides as a carbon source. Isolates exhibited ACC (1-aminocyclopropane-1-carboxylic acid) deaminase, phosphatase, potassium solubilization, and indole acetic acid (IAA) production activities. The phosphate-solubilizing capacity (mg of PO 4 solubilized by 10 8 cells) varied from 0.04 to 0.21. The IAA production potential (μg IAA produced by 10 8 cells in 48 h) of the isolates varied from 0.41 to 9.29. Inoculation of the isolates to maize seed significantly increased shoot and root lengths of maize seedlings. A linear regression model of the plant-growth-promoting activities significantly correlated (p < 0.01) with the growth parameters. Similarly, a correspondence analysis categorized ACC deaminase and IAA production as the major factors contributing 41% and 13.8% variation, respectively, to the growth of maize seedlings.

Stable transformation of Hi-II maize using the particle inflow gun

CSIR Research Space (South Africa)

O'Kennedy, MM

1998-04-01

Full Text Available Focuses on the transformation of the embryogenic type II callus, initiated from cultured immature zygotic embryos of the maize line Hi-II, by microprojectile bombardment using a particle inflow gun. Use of the plasmid pAHC25; Tissue culture...

Exploring the Bacterial Microbiota of Colombian Fermented Maize Dough “Masa Agria” (Maiz Añejo)

Science.gov (United States)

Chaves-Lopez, Clemencia; Serio, Annalisa; Delgado-Ospina, Johannes; Rossi, Chiara; Grande-Tovar, Carlos D.; Paparella, Antonello

2016-01-01

Masa Agria is a naturally fermented maize dough produced in Colombia, very common in the traditional gastronomy. In this study we used culture-dependent and RNA-based pyrosequencing to investigate the bacterial community structure of Masa Agria samples produced in the south west of Colombia. The mean value of cell density was 7.6 log CFU/g of presumptive lactic acid bacteria, 5.4 log cfu/g for presumptive acetic bacteria and 5.6 og CFU/g for yeasts. The abundance of these microorganisms is also responsible for the low pH (3.1–3.7) registered. Although the 16S rRNA pyrosequencing revealed that the analyzed samples were different in bacteria richness and diversity, the genera Lactobacillus, Weissella, and Acetobacter were predominant. In particular, the most common species were Lactobacillus plantarum and Acetobacter fabarum, followed by L. fermentum, L. vaccinostercus, and Pediococcus argentinicus. Several microorganisms of environmental origin, such as Dechloromonas and most of all Sphingobium spp., revealed in each sample, were detected, and also bacteria related to maize, such as Phytoplasma. In conclusion, our results elucidated for the first time the structures of the bacterial communities of Masa Agria samples obtained from different producers, identifying the specific dominant species and revealing a complete picture of the bacterial consortium in this specific niche. The selective pressure of tropical environments may favor microbial biodiversity characterized by a useful technological potential. PMID:27524979

Exploring the bacterial microbiota of Colombian fermented maize dough “Masa Agria” (Maiz Añejo

Directory of Open Access Journals (Sweden)

Clemencia Chaves

2016-07-01

Full Text Available Masa Agria is a naturally fermented maize dough produced in Colombia, very common in the traditional gastronomy. In this study we used culture-dependent and RNA-based pyrosequencing to investigate the bacterial community structure of Masa Agria samples produced in the south west of Colombia. The mean value of cell density was 7.6 Log CFU/g of presumptive lactic acid bacteria (LAB, 5.4 Log cfu/g for presumptive acetic bacteria and 5.6 Log CFU/g for yeasts. The abundance of these microorganisms is also responsible for the low pH (3.1-3.7 registered. Although the 16S rRNA pyrosequencing revealed that the analyzed samples were different in bacteria richness and diversity, the genera Lactobacillus, Weissella and Acetobacter were predominant. In particular, the most common species were Lactobacillus plantarum and Acetobacter fabarum, followed by Lb. fermentum, Lb. vaccinostercus and Pediococcus argentinicus. Several microorganisms of environmental origin, such as Dechloromonas and most of all Sphingobium spp., revealed in each sample, were detected, and also bacteria related to maize, such as Phytoplasma. In conclusion, our results elucidated for the first time the structures of the bacterial communities of Masa Agria samples obtained from different producers, identifying the specific dominant species and revealing a complete picture of the bacterial consortium in this specific niche. The selective pressure of tropical environments may favour microbial biodiversity characterized by a useful technological potential.

Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

Directory of Open Access Journals (Sweden)

Pajić Zorica

2007-01-01

Full Text Available Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a certain trait, the following specific procedures in evaluation of the trait are necessary: the estimation of a popping volume and flake quality in popping maize; the determination of sugars and harvest maturity in sweet maize; the determination of oil in selected samples of high-oil maize types, and so forth. Breeding programmes for speciality maize, except high-amylose maize, have been implemented at the Maize Research Institute, Zemun Polje, Belgrade, for the last 45 years. A great number of high-yielding sweet maize hybrids, popping maize, high-oil and high-lysine, flint and white-seeded maize hybrids were developed during this 45-year period. Auspicious selection and breeding for these traits is facilitated by the abundant genetic variability and technical and technological possibilities necessary for successful selection.

Contexts of offerings and ritual maize in the pictographic record in Central Mexico

Directory of Open Access Journals (Sweden)

Natalia Moragas Segura

2015-01-01

Full Text Available The objective of this article is an initial enquiry into the evidence and classification of the offerings of maize in Central Mexico from the Classic period to early colonial times. In order to achieve this goal, we will analyse the presence of maize in Central Mexico according to the evidence found in mural paintings and some pictographic codices. Two Mesoamerican cultures will be considered to achieve our analysis: the Teotihuacan and Mexico-Tenochtitlan. Maize was instrumental in the performance of daily rituals and in the diet of these ancient Mesoamerican cultures and the cereal also had sacred connotations in pre-Hispanic, colonial and contemporary narratives. We suggest this by reading the iconographic and symbolic representations of corn in the form of seeds and pods, or as an ingredient in cooked foods which are represented in the mural paintings of Teotihuacan as well as some codices of the post-Classic Nahua tradition. These methodological enquiries reveal evidence of a cultural continuity in Central Mexico as a contrasting perspective on the archaeological and ethno-historical period.

C4 photosynthetic machinery: insights from maize chloroplast proteomics

Directory of Open Access Journals (Sweden)

Qi eZhao

2013-04-01

Full Text Available C4 plants exhibit much higher CO2 assimilation rates than C3 plants. The specialized differentiation of mesophyll cell (M and bundle sheath cell (BS type chloroplasts is unique to C4 plants and improves photosynthesis efficiency. Maize (Zea mays is an important crop and model with C4 photosynthetic machinery. Current high-throughput quantitative proteomics approaches (e.g., 2DE, iTRAQ, and shotgun proteomics have been employed to investigate maize chloroplast structure and function. These proteomic studies have provided valuable information on C4 chloroplast protein components, photosynthesis, and other metabolic mechanisms underlying chloroplast biogenesis, stromal and membrane differentiation, as well as response to salinity, high/low temperature, and light stress. This review presents an overview of proteomics advances in maize chloroplast biology.

The iojap gene in maize

Energy Technology Data Exchange (ETDEWEB)

Martienssen, Robert

2001-12-01

The classical maize mutant iojap (Iodent japonica) has variegated green and white leaves. Green sectors have cells with normal chloroplasts whereas white sectors have cells where plastids fail to differentiate. These mutant plastids, when transmitted through the female gametophyte, do not recover in the presence of wild type Iojap. We cloned the Ij locus, and we have investigated the mechanism of epigenetic inheritance and phenotypic expression. More recently, a modifier of this type of variegation, ''Inhibitor of striate'', has also been cloned. Both the iojap and inhibitor of striate proteins have homologs in bacteria and are members of ancient conserved families found in multiple species. These tools can be used to address fundamental questions of inheritance and variegation associated with this classical conundrum of maize genetics. Since the work of Rhoades there has been considerable speculation concerning the nature of the Iojap gene product, the origin of leaf variegation and the mechanism behind the material inheritance of defective plastids. This has made Iojap a textbook paradigm for cytoplasmic inheritance and nuclear-organellar interaction for almost 50 years. Cloning of the Iojap gene in maize, and homologs in other plants and bacteria, provides a new means to address the origin of heteroplastidity, variegation and cytoplasmic inheritance in higher plants.

Uptake, translocation, and debromination of polybrominated diphenyl ethers in maize

Institute of Scientific and Technical Information of China (English)

Moming Zhao; Shuzhen Zhang; Sen Wang; Honglin Huang

2012-01-01

Uptake,translocation and debromination of three polybrominated diphenyl ethers(PBDEs),BDE-28,-47 and-99,in maize were studied in a hydroponic experiment.Roots took up most of the PBDEs in the culture solutions and more highly brominated PBDEs had a stronger uptake capability.PBDEs were detected in the stems and leaves of maize after exposure but rarely detected in the blank control plants.Furthermore,PBDE concentrations decreased from roots to stems and then to leaves,and a very clear decreasing gradient was found in segments upwards along the stem.These altogether provide substantiating evidence for the acropetal translocation of PBDEs in maize.More highly brominated PBDEs were translocated with more difficulty.Radial translocation of PBDEs from nodes to sheath inside maize was also observed.Both acropetal and radial translocations were enhanced at higher transpiration rates,suggesting that PBDE transport was probably driven by the transpiration stream.Debromination of PBDEs occurred in all parts of the maize,and debromination patterns of different parent PBDEs and in different parts of a plant were similar but with some differences.This study for the first time provides direct evidence for the acropetal translocation of PBDEs within plants,elucidates the process of PBDE transport and clarifies the debromination products of PBDEs in maize.

Biosynthesis of DIMBOA in maize using deuterium oxide as a tracer

International Nuclear Information System (INIS)

Peng, S.; Chilton, W.S.

1994-01-01

Growth of root cultures and of shoot cultures of maize (Zea mays) was noticeably inhibited by 30% D2O in liquid medium. Increasing the concentration of D2O in the medium decreased the concentration of DIMBOA [2,4-dihydroxy-7-methoxy 2H-1,4-benzoxazin-3(4H)-one] and the biomass of roots and shoots. DIMBOA was converted to MBOA [6-methoxy-2(3H)-benzoxazolone] and analysed by mass spectroscopy. Both root cultures and shoot cultures grown on 30% D2O incorporated deuterium at non-exchangeable sites of MBOA (15.6% and 16.1%, respectively), indicating that maize roots and shoots are independently capable of synthesizing DIMBOA from carbohydrate precursors. EI-MS and H-1 NMR showed that there was little selectivity in deuterium labelling between hydrogens at aromatic position 4, 5 or 7, consistent with the major amount of deuterium incorporation occurring prior to synthesis of shikimic acid

Biotechnological characteristics of callusogenesis in maize immature embryo culture under the influence of abscisic acid and 6-benzylaminopurine

Directory of Open Access Journals (Sweden)

O. E. Abraimova

2010-02-01

Full Text Available The effect of abscisic acid and 6-benzylaminopurine on the induction of callus tissue in maize immature embryo culture was studied. For the majority of investigated genotypes abscisic acid stimulated, but 6-benzylaminopurine inhibited the formation of morphogenic calli in induction medium. It was noted that genotype appeared to be an important factor that determined the character of the influence of phytohormonal composition of the medium on the induction of the specific types of calli. Using of 0.04-0.10 mg/l abscisic acid is recommended for biotechnological production of morphogenic callus tissue in dependence of donor plant genotype.

Breeding of maize types with specific traits at the Maize Research Institute, Zemun Polje

OpenAIRE

Pajić Zorica

2007-01-01

Maize is primarily grown as an energy crop, but the use of different specific versions, such as high-oil maize, high-lysine maize, waxy maize, white-seeded maize, popping maize and sweet maize, is quite extensive. Speciality maize, due to its traits and genetic control of these traits, requires a particular attention in handling breeding material during the processes of breeding. It is especially related to prevention of uncontrolled pollination. In order to provide successful selection for a...

Polymorphisms in O-methyltransferase genes are associated with stover cell wall digestibility in European maize (Zea mays L.)

DEFF Research Database (Denmark)

Brenner, Everton A; Zein, Imad; Chen, Yongsheng

2010-01-01

Background OMT (O-methyltransferase) genes are involved in lignin biosynthesis, which relates to stover cell wall digestibility. Reduced lignin content is an important determinant of both forage quality and ethanol conversion efficiency of maize stover. Results Variation in genomic sequences codi...

Ethylene Synthesis and Auxin Augmentation in Pistil Tissues are Important for Egg Cell Differentiation after Pollination in Maize

Czech Academy of Sciences Publication Activity Database

Mól, R.; Filek, M.; Macháčková, Ivana; Rochon, E.

2004-01-01

Roč. 45, č. 10 (2004), s. 1396-1405 ISSN 0032-0781 R&D Projects: GA AV ČR KSK5052113 Keywords : egg cell maturation * growth regulators * Maize Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.258, year: 2004

Transition zone cells reach G2 phase before initiating elongation in maize root apex

Directory of Open Access Journals (Sweden)

M. Victoria Alarcón

2017-06-01

Full Text Available Root elongation requires cell divisions in the meristematic zone and cell elongation in the elongation zone. The boundary between dividing and elongating cells is called the transition zone. In the meristem zone, initial cells are continuously dividing, but on the basal side of the meristem cells exit the meristem through the transition zone and enter in the elongation zone, where they stop division and rapidly elongate. Throughout this journey cells are accompanied by changes in cell cycle progression. Flow cytometry analysis showed that meristematic cells are in cycle, but exit when they enter the elongation zone. In addition, the percentage of cells in G2 phase (4C strongly increased from the meristem to the elongation zone. However, we did not observe remarkable changes in the percentage of cells in cell cycle phases along the entire elongation zone. These results suggest that meristematic cells in maize root apex stop the cell cycle in G2 phase after leaving the meristem.

The proteome and phosphoproteome of maize pollen uncovers fertility candidate proteins.

Science.gov (United States)

Chao, Qing; Gao, Zhi-Fang; Wang, Yue-Feng; Li, Zhe; Huang, Xia-He; Wang, Ying-Chun; Mei, Ying-Chang; Zhao, Biligen-Gaowa; Li, Liang; Jiang, Yu-Bo; Wang, Bai-Chen

2016-06-01

Maize is unique since it is both monoecious and diclinous (separate male and female flowers on the same plant). We investigated the proteome and phosphoproteome of maize pollen containing modified proteins and here we provide a comprehensive pollen proteome and phosphoproteome which contain 100,990 peptides from 6750 proteins and 5292 phosphorylated sites corresponding to 2257 maize phosphoproteins, respectively. Interestingly, among the total 27 overrepresented phosphosite motifs we identified here, 11 were novel motifs, which suggested different modification mechanisms in plants compared to those of animals. Enrichment analysis of pollen phosphoproteins showed that pathways including DNA synthesis/chromatin structure, regulation of RNA transcription, protein modification, cell organization, signal transduction, cell cycle, vesicle transport, transport of ions and metabolisms, which were involved in pollen development, the following germination and pollen tube growth, were regulated by phosphorylation. In this study, we also found 430 kinases and 105 phosphatases in the maize pollen phosphoproteome, among which calcium dependent protein kinases (CDPKs), leucine rich repeat kinase, SNF1 related protein kinases and MAPK family proteins were heavily enriched and further analyzed. From our research, we also uncovered hundreds of male sterility-associated proteins and phosphoproteins that might influence maize productivity and serve as targets for hybrid maize seed production. At last, a putative complex signaling pathway involving CDPKs, MAPKs, ubiquitin ligases and multiple fertility proteins was constructed. Overall, our data provides new insight for further investigation of protein phosphorylation status in mature maize pollen and construction of maize male sterile mutants in the future.

Hormonal responses during early embryogenesis in maize.

Science.gov (United States)

Chen, Junyi; Lausser, Andreas; Dresselhaus, Thomas

2014-04-01

Plant hormones have been shown to regulate key processes during embryogenesis in the model plant Arabidopsis thaliana, but the mechanisms that determine the peculiar embryo pattern formation of monocots are largely unknown. Using the auxin and cytokinin response markers DR5 and TCSv2 (two-component system, cytokinin-responsive promoter version #2), as well as the auxin efflux carrier protein PIN1a (PINFORMED1a), we have studied the hormonal response during early embryogenesis (zygote towards transition stage) in the model and crop plant maize. Compared with the hormonal response in Arabidopsis, we found that detectable hormone activities inside the developing maize embryo appeared much later. Our observations indicate further an important role of auxin, PIN1a and cytokinin in endosperm formation shortly after fertilization. Apparent auxin signals within adaxial endosperm cells and cytokinin responses in the basal endosperm transfer layer as well as chalazal endosperm are characteristic for early seed development in maize. Moreover, auxin signalling in endosperm cells is likely to be involved in exogenous embryo patterning as auxin responses in the endosperm located around the embryo proper correlate with adaxial embryo differentiation and outgrowth. Overall, the comparison between Arabidopsis and maize hormone response and flux suggests intriguing mechanisms in monocots that are used to direct their embryo patterning, which is significantly different from that of eudicots.

Application of Fungicides and Microalgal Phenolic Extracts for the Direct Control of Fumonisin Contamination in Maize.

Science.gov (United States)

Scaglioni, Priscila Tessmer; Blandino, Massimo; Scarpino, Valentina; Giordano, Debora; Testa, Giulio; Badiale-Furlong, Eliana

2018-05-16

Fungicides and, for the first time, microalgal phenolic extracts (MPE) from Spirulina sp. and Nannochloropsis sp. were applied on maize culture media under field conditions to evaluate their ability to minimize Fusarium species development and fumonisin production. An in vitro assay against F. verticillioides was carried out using maize grains as the culture medium. An open-field experiment was carried out in Northwest Italy under natural infection conditions. The compared treatments were factorial combinations of two insecticide treatments (an untreated control and pyrethroid, used against European Corn Borer), four antifungal treatments (an untreated control, MPE from Spirulina sp., MPE from Nannochloropsis sp., and a synthetic fungicide), and two timings of the application of the antifungal compounds (at maize flowering and at the milk stage). The MPE compounds were capable of inhibiting fumonisin production in vitro more efficiently than tebuconazole. Insecticide application reduced the infection by Fusarium species and subsequent fumonisin contamination. However, fumonisins in maize fields were not significantly controlled by either fungicide or MPE application.

Decomposition and fertilizing effects of maize stover and chromolaena odorata on maize yield

International Nuclear Information System (INIS)

Tetteh, F.M.; Safo, E.Y.; Quansah, C.

2008-01-01

The quality, rates of decomposition and the fertilizing effect of chromolaena odorata, and maize stover were determined in field experiments as surface application or buried in litter bags. Studies on the effect of plant materials of contrasting qualities (maize stover and C. odorata) applied sole (10 Mg ha -1 ) and mixed, on maize grain and biomass yield were also conducted on the Asuansi (Ferric Acrisol) soil series. Total nitrogen content of the residues ranged from 0.85% in maize stover to 3.50% in C. odorata. Organic carbon ranged from 34.90% in C. odorata to 48.50% in maize stover. Phosphorus ranged from 0.10% in maize stover to 0.76% in C. odorata. In the wet season, the decomposition rate constants (k) were 0.0319 day -1 for C. odorata, and 0.0081 for maize stover. In the dry season, the k values were 0.0083 for C. odorata, and 0.0072 day -1 for maize stover. Burying of the plant materials reduced the half-life (t 50 ) periods from 18 to 10 days for C. odorata, and 45 to 20 days for maize stover. Maize grain yield of 2556 kg ha -1 was obtained in sole C. odorata (10 Mg ha -1 ) compared with 2167 kg ha -1 for maize stover. Mixing of maize stover and C. odorata residues improved the nutrient content as well as nutrient release by the mixtures resulting in greater maize grain yields in the mixtures than the sole maize stover treatment. It is recommended that C. odorata be used as green manure, mulching or composting material to improve fertility. (au)

[Effect of reduced N application on soil N residue and N loss in maize-soybean relay strip intercropping system].

Science.gov (United States)

Liu, Xiao-Ming; Yong, Tai-Wen; Liu, Wen-Yu; Su, Ben-Ying; Song, Chun; Yang, Feng; Wang, Xiao-Chun; Yang, Wen-Yu

2014-08-01

A field experiment was conducted in 2012, including three planting pattern (maize-soybean relay strip intercropping, mono-cultured maize and soybean) and three nitrogen application level [0 kg N x hm(-2), 180 kg N x hm(-2) (reduced N) and 240 kg N x hm(-2) (normal N)]. Fields were assigned to different treatments in a randomized block design with three replicates. The objective of this work was to analyze the effects of planting patterns and nitrogen application rates on plant N uptake, soil N residue and N loss. After fertilization applications, NH4(+)-N and NO3(-)-N levels increased in the soil of intercropped maize but decreased in the soil of intercropped soybean. Compared with mono-crops, the soil N residue and loss of intercropped soybean were reduced, while those of intercropped maize were increased and decreased, respectively. With the reduced rate of N application, N residue rate, N loss rate and ammonia volatilization loss rate of the maize-soybean intercropping relay strip system were decreased by 17.7%, 21.5% and 0.4% compared to mono-cultured maize, but increased by 2.0%, 19.8% and 0.1% compared to mono-cultured soybean, respectively. Likewise, the reduced N application resulted in reductions in N residue, N loss, and the N loss via ammonia volatilization in the maize-soybean relay strip intercropping system compared with the conventional rate of N application adopted by local farmers, and the N residue rate, N loss rate and ammonia volatilization loss rate reduced by 12.0%, 15.4% and 1.2%, respectively.

Perfusion based cell culture chips

DEFF Research Database (Denmark)

Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

2010-01-01

Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures...... and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers....

Decontamination of Fumonisin B1 in maize grain by Pleurotus eryngii and antioxidant enzymes

Directory of Open Access Journals (Sweden)

Miriam HAIDUKOWSKI

2017-05-01

Full Text Available Fumonisin B1 (FB1 is among the most common mycotoxins found in maize kernels and maize products worldwide. The microbiological process of detoxification and transformation of toxic organic pollutants is a promising method for foodstuffs decontamination. Some basidiomycetes, such as the Pleurotus eryngii species complex, include several important commercial edible varieties that can detoxify polycyclic organic compounds and a range of wastes and pollutants. We investigated the potential role of P. eryngii, one of the most consumed mushrooms, in the decontamination of FB1 in maize. In addition, selected antioxidant enzymes, (soluble peroxidase (POD, catalase (CAT and ascorbate peroxidase, primarily involved in control of cell hydrogen peroxide levels, and lignin degradation, were analyzed, to evaluate their contributions to the molecular mechanisms of FB1 by P. eryngii. FB1 decontamination by P. eryngii and involvement of CAT and POD enzymes in the control of toxic decontamination levels of H2O2 were demonstrated. A consistent reduction of FB1 was observed at different incubation times. The average decrease levels of FB1, with respect to the control cultures, ranged from 45 to 61% (RSD < 15%. This study is a possible eco-friendly approach to reducing this mycotoxin in the feed supply chains.

Cell Culture Made Easy.

Science.gov (United States)

Dye, Frank J.

1985-01-01

Outlines steps to generate cell samples for observation and experimentation. The procedures (which use ordinary laboratory equipment) will establish a short-term primary culture of normal mammalian cells. Information on culture vessels and cell division and a list of questions to generate student interest and involvement in the topics are…

A biocompatible micro cell culture chamber (mu CCC) for the culturing and on-line monitoring of eukaryote cells

DEFF Research Database (Denmark)

Stangegaard, Michael; Petronis, Sarunas; Jørgensen, Anders Michael

2006-01-01

culture chip compared to cell culture flasks. The cell culture chip could without further modification support cell growth of two other cell lines. Light coming from the microscope lamp during optical recordings of the cells was the only external factor identified, that could have a negative effect...... on cell survival. Low grade light exposure was however compatible with optical recordings as well as cell viability. These results strongly indicate that a cell culture chip could be constructed that allowed for on-line optical recording of cellular events without affecting the cell culturing condition...

A biocompatible micro cell culture chamber (microCCC) for the culturing and on-line monitoring of eukaryote cells

DEFF Research Database (Denmark)

Stangegaard, Michael; Petronis, Sarunas; Jørgensen, A M

2006-01-01

culture chip compared to cell culture flasks. The cell culture chip could without further modification support cell growth of two other cell lines. Light coming from the microscope lamp during optical recordings of the cells was the only external factor identified, that could have a negative effect...... on cell survival. Low grade light exposure was however compatible with optical recordings as well as cell viability. These results strongly indicate that a cell culture chip could be constructed that allowed for on-line optical recording of cellular events without affecting the cell culturing condition...

MaizeGDB: The Maize Genetics and Genomics Database.

Science.gov (United States)

Harper, Lisa; Gardiner, Jack; Andorf, Carson; Lawrence, Carolyn J

2016-01-01

MaizeGDB is the community database for biological information about the crop plant Zea mays. Genomic, genetic, sequence, gene product, functional characterization, literature reference, and person/organization contact information are among the datatypes stored at MaizeGDB. At the project's website ( http://www.maizegdb.org ) are custom interfaces enabling researchers to browse data and to seek out specific information matching explicit search criteria. In addition, pre-compiled reports are made available for particular types of data and bulletin boards are provided to facilitate communication and coordination among members of the community of maize geneticists.

Maize kernel evolution:From teosinte to maize

Science.gov (United States)

Maize is the most productive and highest value commodity in the US and around the world: over 1 billion tons were produced each year in 2013 and 2014. Together, maize, rice and wheat comprise over 60% of the world’s caloric intake, with wide regional variability in the importance of each crop. The i...

A novel beta-glucosidase from the cell wall of maize (Zea mays L.): rapid purification and partial characterization

Science.gov (United States)

Nematollahi, W. P.; Roux, S. J.

1999-01-01

Plants have a variety of glycosidic conjugates of hormones, defense compounds, and other molecules that are hydrolyzed by beta-glucosidases (beta-D-glucoside glucohydrolases, E.C. 3.2.1.21). Workers have reported several beta-glucosidases from maize (Zea mays L.; Poaceae), but have localized them mostly by indirect means. We have purified and partly characterized a 58-Ku beta-glucosidase from maize, which we conclude from a partial sequence analysis, from kinetic data, and from its localization is not identical to any of those already reported. A monoclonal antibody, mWP 19, binds this enzyme, and localizes it in the cell walls of maize coleoptiles. An earlier report showed that mWP19 inhibits peroxidase activity in crude cell wall extracts and can immunoprecipitate peroxidase activity from these extracts, yet purified preparations of the 58 Ku protein had little or no peroxidase activity. The level of sequence similarity between beta-glucosidases and peroxidases makes it unlikely that these enzymes share epitopes in common. Contrary to a previous conclusion, these results suggest that the enzyme recognized by mWP19 is not a peroxidase, but there is a wall peroxidase closely associated with the 58 Ku beta-glucosidase in crude preparations. Other workers also have co-purified distinct proteins with beta-glucosidases. We found no significant charge in the level of immunodetectable beta-glucosidase in mesocotyls or coleoptiles that precedes the red light-induced changes in the growth rate of these tissues.

Harnessing maize biodiversity

Science.gov (United States)

Maize is a remarkably diverse species, adapted to a wide range of climatic conditions and farming practices. The latitudinal range of maize is immense, ranging from 54°N in Alberta, Canada, to 45°S in the province of Chubut, Argentina. In terms of altitude, maize is cultivated from sea level to 4000...

Cell Culturing of Cytoskeleton

Science.gov (United States)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc., has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc., is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

9 CFR 101.6 - Cell cultures.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Cell cultures. 101.6 Section 101.6..., SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS DEFINITIONS § 101.6 Cell cultures. When used in conjunction with or in reference to cell cultures, which may be referred to as tissue cultures...

Preceramic maize from Paredones and Huaca Prieta, Peru.

Science.gov (United States)

Grobman, Alexander; Bonavia, Duccio; Dillehay, Tom D; Piperno, Dolores R; Iriarte, José; Holst, Irene

2012-01-31

Maize (Zea mays ssp. mays) is among the world's most important and ancient domesticated crops. Although the chronology of its domestication and initial dispersals out of Mexico into Central and South America has become more clear due to molecular and multiproxy archaeobotanical research, important problems remain. Among them is the paucity of information on maize's early morphological evolution and racial diversification brought about in part by the poor preservation of macrofossils dating to the pre-5000 calibrated years before the present period from obligate dispersal routes located in the tropical forest. We report newly discovered macrobotanical and microbotanical remains of maize that shed significant light on the chronology, land race evolution, and cultural contexts associated with the crop's early movements into South America and adaptation to new environments. The evidence comes from the coastal Peruvian sites of Paredones and Huaca Prieta, Peru; dates from the middle and late preceramic and early ceramic periods (between ca. 6700 and 3000 calibrated years before the present); and constitutes some of the earliest known cobs, husks, stalks, and tassels. The macrobotanical record indicates that a diversity of racial complexes characteristic of the Andean region emerged during the preceramic era. In addition, accelerator mass spectrometry radiocarbon determinations carried out directly on different structures of preserved maize plants strongly suggest that assays on burned cobs are more reliable than those on unburned cobs. Our findings contribute to knowledge of the early diffusion of maize and agriculture and have broader implications for understanding the development of early preindustrial human societies.

Control of Fusarium verticillioides, cause of ear rot of maize, by Pseudomonas fluorescens.

Science.gov (United States)

Nayaka, Siddaiah Chandra; Shankar, Arakere C Udaya; Reddy, Munagala S; Niranjana, Siddapura R; Prakash, Harishchandra S; Shetty, Hunthrike S; Mortensen, Carmen N

2009-07-01

Maize is one of the staple food crops grown in India. Fusarium verticillioides (Sacc.) Nirenberg is the most important fungal pathogen of maize, associated with diseases such as ear rot and kernel rot. Apart from the disease, it is capable of producing fumonisins, which have elicited considerable attention over the past decade owing to their association with animal disease syndromes. Hence, the present study was conducted to evaluate ecofriendly approaches by using a maize rhizosphere isolate of Pseudomonas fluorescens (Trev.) Mig. and its formulation to control ear rot disease and fumonisin accumulation, and also to study the capacity to promote growth and yield of maize. In vitro assays were conducted to test the efficacy of P. fluorescens as a seed treatment on seed germination, seedling vigour and also the incidence of F. verticillioides in different maize cultivars. The field trials included both seed treatment and foliar spray. For all the experiments, P. fluorescens was formulated using corn starch, wheat bran and talc powder. In each case there were three different treatments of P. fluorescens, a non-treated control and chemical control. Pure culture and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F. verticillioides and the level of fumonisins to a maximum extent compared with the other treatments. The study demonstrates the potential role of P. fluorescens and its formulations in ear rot disease management. The biocontrol potential of this isolate is more suited for fumonisin reduction in maize kernels intended for human and animal feed. (c) 2009 Society of Chemical Industry.

Screening for salt tolerance in maize (zea mays l.) hybrids at an early seedling stage

International Nuclear Information System (INIS)

Akram, M.; Mohsan; Ashraf, M.Y.; Ahmad, R.; Waraich, E.A.

2010-01-01

An efficient and simple mass screening technique for selection of maize hybrids for salt tolerance has been developed. Genetic variation for salt tolerance was assessed in hybrid maize (Zea mays L.) using solution-culture technique. The study was conducted in solution culture exposed to four salinity levels (control, 40, 80 and 120 mM NaCl). Seven days old maize seedlings were transplanted in themopol sheet in iron tubs containing one half strength Hoagland nutrient solutions and salinized with common salt (NaCl). The experiment was conducted in the rain protected wire house of Stress Physiology Laboratory of NIAB, Faisalabad, Pakistan. Ten maize hybrids were used for screening against four salinity levels. Seedling of each hybrid was compared for their growth under saline conditions as a percentage of the control values. Considerable variations were observed in the root, shoot length and biomass of different hybrids at different salinity levels. The leaf sample analyzed for inorganic osmolytes (sodium, potassium and calcium) showed that hybrid Pioneer 32B33 and Pioneer 30Y87 have high biomass, root shoot fresh weight and high ratio and showed best salt tolerance performance at all salinity levels on overall basis. (author)

ProFITS of maize: a database of protein families involved in the transduction of signalling in the maize genome

Directory of Open Access Journals (Sweden)

Zhang Zhenhai

2010-10-01

Full Text Available Abstract Background Maize (Zea mays ssp. mays L. is an important model for plant basic and applied research. In 2009, the B73 maize genome sequencing made a great step forward, using clone by clone strategy; however, functional annotation and gene classification of the maize genome are still limited. Thus, a well-annotated datasets and informative database will be important for further research discoveries. Signal transduction is a fundamental biological process in living cells, and many protein families participate in this process in sensing, amplifying and responding to various extracellular or internal stimuli. Therefore, it is a good starting point to integrate information on the maize functional genes involved in signal transduction. Results Here we introduce a comprehensive database 'ProFITS' (Protein Families Involved in the Transduction of Signalling, which endeavours to identify and classify protein kinases/phosphatases, transcription factors and ubiquitin-proteasome-system related genes in the B73 maize genome. Users can explore gene models, corresponding transcripts and FLcDNAs using the three abovementioned protein hierarchical categories, and visualize them using an AJAX-based genome browser (JBrowse or Generic Genome Browser (GBrowse. Functional annotations such as GO annotation, protein signatures, protein best-hits in the Arabidopsis and rice genome are provided. In addition, pre-calculated transcription factor binding sites of each gene are generated and mutant information is incorporated into ProFITS. In short, ProFITS provides a user-friendly web interface for studies in signal transduction process in maize. Conclusion ProFITS, which utilizes both the B73 maize genome and full length cDNA (FLcDNA datasets, provides users a comprehensive platform of maize annotation with specific focus on the categorization of families involved in the signal transduction process. ProFITS is designed as a user-friendly web interface and it is

Histone acetylation associated up-regulation of the cell wall related genes is involved in salt stress induced maize root swelling

OpenAIRE

Li, Hui; Yan, Shihan; Zhao, Lin; Tan, Junjun; Zhang, Qi; Gao, Fei; Wang, Pu; Hou, Haoli; Li, Lijia

2014-01-01

Background Salt stress usually causes crop growth inhibition and yield decrease. Epigenetic regulation is involved in plant responses to environmental stimuli. The epigenetic regulation of the cell wall related genes associated with the salt-induced cellular response is still little known. This study aimed to analyze cell morphological alterations in maize roots as a consequence of excess salinity in relation to the transcriptional and epigenetic regulation of the cell wall related protein ge...

The effect of feeding Bt MON810 maize to pigs for 110 days on intestinal microbiota.

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Stefan G Buzoianu

Full Text Available OBJECTIVE: To assess the effects of feeding Bt MON810 maize to pigs for 110 days on the intestinal microbiota. METHODOLOGY/PRINCIPAL FINDINGS: Forty male pigs (∼40 days old were blocked by weight and litter ancestry and assigned to one of four treatments; 1 Isogenic maize-based diet for 110 days (Isogenic; 2 Bt maize-based diet (MON810 for 110 days (Bt; 3 Isogenic maize-based diet for 30 days followed by a Bt maize-based diet for 80 days (Isogenic/Bt; 4 Bt maize-based diet for 30 days followed by an isogenic maize-based diet for 80 days (Bt/Isogenic. Enterobacteriaceae, Lactobacillus and total anaerobes were enumerated in the feces using culture-based methods on days 0, 30, 60 and 100 of the study and in ileal and cecal digesta on day 110. No differences were found between treatments for any of these counts at any time point. The relative abundance of cecal bacteria was also determined using high-throughput 16 S rRNA gene sequencing. No differences were observed in any bacterial taxa between treatments, with the exception of the genus Holdemania which was more abundant in the cecum of pigs fed the isogenic/Bt treatment compared to pigs fed the Bt treatment (0.012 vs 0.003%; P≤0.05. CONCLUSIONS/SIGNIFICANCE: Feeding pigs a Bt maize-based diet for 110 days did not affect counts of any of the culturable bacteria enumerated in the feces, ileum or cecum. Neither did it influence the composition of the cecal microbiota, with the exception of a minor increase in the genus Holdemania. As the role of Holdemania in the intestine is still under investigation and no health abnormalities were observed, this change is not likely to be of clinical significance. These results indicate that feeding Bt maize to pigs in the context of its influence on the porcine intestinal microbiota is safe.

Transfer of 65Zn in maize -mycorrhizal systems: a potential mechanism to alleviate Zn deficiency in maize

International Nuclear Information System (INIS)

Subramanian, K.S.; Tenshia, Virgin

2017-01-01

Mycorrhizas are root associated fungi and obligate symbionts known to improve the nutritional status of the host plant as a direct consequence of transfer of slowly diffusing nutrients such as zinc. The Zn use efficiency by crops hardly exceeds 2-5 per cent and major portion of the Zn gets accumulated in soil in various pools which are not available to plants. Further, mycorrhizal symbiosis alters the chemical and biochemical properties of rhizosphere that affect the isotopic parameters such as A value, E value and L value. These parameters were measured for both mycorrhizal and non-mycorrhizal maize plants. A pot culture experiment was conducted to determine the availability of Zn using isotopic dilution techniques. Maize plants were grown in pots inoculated with (M+) or without (M-) mycorrhizal fungus Glomus intraradices. Tagged 65 ZnSO 4 was applied to soil at the time of sowing

Cyst(e)ine Is the Transport Metabolite of Assimilated Sulfur from Bundle-Sheath to Mesophyll Cells in Maize Leaves1

Science.gov (United States)

Burgener, Marta; Suter, Marianne; Jones, Stephanie; Brunold, Christian

1998-01-01

The intercellular distribution of the enzymes and metabolites of assimilatory sulfate reduction and glutathione synthesis was analyzed in maize (Zea mays L. cv LG 9) leaves. Mesophyll cells and strands of bundle-sheath cells from second leaves of 11-d-old maize seedlings were obtained by two different mechanical-isolation methods. Cross-contamination of cell preparations was determined using ribulose bisphosphate carboxylase (EC 4.1.1.39) and nitrate reductase (EC 1.6.6.1) as marker enzymes for bundle-sheath and mesophyll cells, respectively. ATP sulfurylase (EC 2.7.7.4) and adenosine 5′-phosphosulfate sulfotransferase activities were detected almost exclusively in the bundle-sheath cells, whereas GSH synthetase (EC 6.3.2.3) and cyst(e)ine, γ-glutamylcysteine, and glutathione were located predominantly in the mesophyll cells. Feeding experiments using [35S]sulfate with intact leaves indicated that cyst(e)ine was the transport metabolite of reduced sulfur from bundle-sheath to mesophyll cells. This result was corroborated by tracer experiments, which showed that isolated bundle-sheath strands fed with [35S]sulfate secreted radioactive cyst(e)ine as the sole thiol into the resuspending medium. The results presented in this paper show that assimilatory sulfate reduction is restricted to the bundle-sheath cells, whereas the formation of glutathione takes place predominantly in the mesophyll cells, with cyst(e)ine functioning as a transport metabolite between the two cell types. PMID:9536048

Fate of Transgenic DNA from Orally Administered Bt MON810 Maize and Effects on Immune Response and Growth in Pigs

Science.gov (United States)

Walsh, Maria C.; Buzoianu, Stefan G.; Gardiner, Gillian E.; Rea, Mary C.; Gelencsér, Eva; Jánosi, Anna; Epstein, Michelle M.; Ross, R. Paul; Lawlor, Peadar G.

2011-01-01

We assessed the effect of short-term feeding of genetically modified (GM: Bt MON810) maize on immune responses and growth in weanling pigs and determined the fate of the transgenic DNA and protein in-vivo. Pigs were fed a diet containing 38.9% GM or non-GM isogenic parent line maize for 31 days. We observed that IL-12 and IFNγ production from mitogenic stimulated peripheral blood mononuclear cells decreased (PGM maize exposure. While Cry1Ab-specific IgG and IgA were not detected in the plasma of GM maize-fed pigs, the detection of the cry1Ab gene and protein was limited to the gastrointestinal digesta and was not found in the kidneys, liver, spleen, muscle, heart or blood. Feeding GM maize to weanling pigs had no effect on growth performance or body weight. IL-6 and IL-4 production from isolated splenocytes were increased (PGM maize while the proportion of CD4+ T cells in the spleen decreased. In the ileum, the proportion of B cells and macrophages decreased while the proportion of CD4+ T cells increased in GM maize-fed pigs. IL-8 and IL-4 production from isolated intraepithelial and lamina propria lymphocytes were also increased (PGM maize. In conclusion, there was no evidence of cry1Ab gene or protein translocation to the organs and blood of weaning pigs. The growth of pigs was not affected by feeding GM maize. Alterations in immune responses were detected; however, their biologic relevance is questionable. PMID:22132091

Simplified and representative bacterial community of maize roots.

Science.gov (United States)

Niu, Ben; Paulson, Joseph Nathaniel; Zheng, Xiaoqi; Kolter, Roberto

2017-03-21

Plant-associated microbes are important for the growth and health of their hosts. As a result of numerous prior studies, we know that host genotypes and abiotic factors influence the composition of plant microbiomes. However, the high complexity of these communities challenges detailed studies to define experimentally the mechanisms underlying the dynamics of community assembly and the beneficial effects of such microbiomes on plant hosts. In this work, from the distinctive microbiota assembled by maize roots, through host-mediated selection, we obtained a greatly simplified synthetic bacterial community consisting of seven strains ( Enterobacter cloacae , Stenotrophomonas maltophilia, Ochrobactrum pituitosum, Herbaspirillum frisingense, Pseudomonas putida, Curtobacterium pusillum , and Chryseobacterium indologenes ) representing three of the four most dominant phyla found in maize roots. By using a selective culture-dependent method to track the abundance of each strain, we investigated the role that each plays in community assembly on roots of axenic maize seedlings. Only the removal of E. cloacae led to the complete loss of the community, and C. pusillum took over. This result suggests that E. cloacae plays the role of keystone species in this model ecosystem. In planta and in vitro, this model community inhibited the phytopathogenic fungus Fusarium verticillioides , indicating a clear benefit to the host. Thus, combined with the selective culture-dependent quantification method, our synthetic seven-species community representing the root microbiome has the potential to serve as a useful system to explore how bacterial interspecies interactions affect root microbiome assembly and to dissect the beneficial effects of the root microbiota on hosts under laboratory conditions in the future.

Microfluidic cell culture systems for drug research.

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Wu, Min-Hsien; Huang, Song-Bin; Lee, Gwo-Bin

2010-04-21

In pharmaceutical research, an adequate cell-based assay scheme to efficiently screen and to validate potential drug candidates in the initial stage of drug discovery is crucial. In order to better predict the clinical response to drug compounds, a cell culture model that is faithful to in vivo behavior is required. With the recent advances in microfluidic technology, the utilization of a microfluidic-based cell culture has several advantages, making it a promising alternative to the conventional cell culture methods. This review starts with a comprehensive discussion on the general process for drug discovery and development, the role of cell culture in drug research, and the characteristics of the cell culture formats commonly used in current microfluidic-based, cell-culture practices. Due to the significant differences in several physical phenomena between microscale and macroscale devices, microfluidic technology provides unique functionality, which is not previously possible by using traditional techniques. In a subsequent section, the niches for using microfluidic-based cell culture systems for drug research are discussed. Moreover, some critical issues such as cell immobilization, medium pumping or gradient generation in microfluidic-based, cell-culture systems are also reviewed. Finally, some practical applications of microfluidic-based, cell-culture systems in drug research particularly those pertaining to drug toxicity testing and those with a high-throughput capability are highlighted.

Use of an adaptable cell culture kit for performing lymphocyte and monocyte cell cultures in microgravity

Science.gov (United States)

Hatton, J. P.; Lewis, M. L.; Roquefeuil, S. B.; Chaput, D.; Cazenave, J. P.; Schmitt, D. A.

1998-01-01

The results of experiments performed in recent years on board facilities such as the Space Shuttle/Spacelab have demonstrated that many cell systems, ranging from simple bacteria to mammalian cells, are sensitive to the microgravity environment, suggesting gravity affects fundamental cellular processes. However, performing well-controlled experiments aboard spacecraft offers unique challenges to the cell biologist. Although systems such as the European 'Biorack' provide generic experiment facilities including an incubator, on-board 1-g reference centrifuge, and contained area for manipulations, the experimenter must still establish a system for performing cell culture experiments that is compatible with the constraints of spaceflight. Two different cell culture kits developed by the French Space Agency, CNES, were recently used to perform a series of experiments during four flights of the 'Biorack' facility aboard the Space Shuttle. The first unit, Generic Cell Activation Kit 1 (GCAK-1), contains six separate culture units per cassette, each consisting of a culture chamber, activator chamber, filtration system (permitting separation of cells from supernatant in-flight), injection port, and supernatant collection chamber. The second unit (GCAK-2) also contains six separate culture units, including a culture, activator, and fixation chambers. Both hardware units permit relatively complex cell culture manipulations without extensive use of spacecraft resources (crew time, volume, mass, power), or the need for excessive safety measures. Possible operations include stimulation of cultures with activators, separation of cells from supernatant, fixation/lysis, manipulation of radiolabelled reagents, and medium exchange. Investigations performed aboard the Space Shuttle in six different experiments used Jurkat, purified T-cells or U937 cells, the results of which are reported separately. We report here the behaviour of Jurkat and U937 cells in the GCAK hardware in ground

EFFECT OF MAIZE INTERCROP PLANT DENSITIES ON YIELD ...

African Journals Online (AJOL)

ACSS

protein maize (Zea mays L.) in combating vitamin A and protein malnutrition, small land holdings by rural poor farmers still ... A cet effet, l'association des cultures doublée d'une densité optimale des plants dans les systems ..... their foliar area to lessen water loss. Also ..... Valenzuela, H.R., O'Hair, S.K. and Schaffer, B. 1991 ...

Whole transcriptome profiling of maize during early somatic embryogenesis reveals altered expression of stress factors and embryogenesis-related genes.

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Stella A G D Salvo

Full Text Available Embryogenic tissue culture systems are utilized in propagation and genetic engineering of crop plants, but applications are limited by genotype-dependent culture response. To date, few genes necessary for embryogenic callus formation have been identified or characterized. The goal of this research was to enhance our understanding of gene expression during maize embryogenic tissue culture initiation. In this study, we highlight the expression of candidate genes that have been previously regarded in the literature as having important roles in somatic embryogenesis. We utilized RNA based sequencing (RNA-seq to characterize the transcriptome of immature embryo explants of the highly embryogenic and regenerable maize genotype A188 at 0, 24, 36, 48, and 72 hours after placement of explants on tissue culture initiation medium. Genes annotated as functioning in stress response, such as glutathione-S-transferases and germin-like proteins, and genes involved with hormone transport, such as PINFORMED, increased in expression over 8-fold in the study. Maize genes with high sequence similarity to genes previously described in the initiation of embryogenic cultures, such as transcription factors BABY BOOM, LEAFY COTYLEDON, and AGAMOUS, and important receptor-like kinases such as SOMATIC EMBRYOGENESIS RECEPTOR LIKE KINASES and CLAVATA, were also expressed in this time course study. By combining results from whole genome transcriptome analysis with an in depth review of key genes that play a role in the onset of embryogenesis, we propose a model of coordinated expression of somatic embryogenesis-related genes, providing an improved understanding of genomic factors involved in the early steps of embryogenic culture initiation in maize and other plant species.

Comparison of Selenium Toxicity in Sunflower and Maize Seedlings Grown in Hydroponic Cultures.

Science.gov (United States)

Garousi, Farzaneh; Veres, Szilvia; Kovács, Béla

2016-11-01

Several studies have demonstrated that selenium (Se) at low concentrations is beneficial, whereas high Se concentrations can induce toxicity. Controlling Se uptake, metabolism, translocation and accumulation in plants is important to decrease potential health risks and helping to select proper biofortification methods to improve the nutritional content of plant-based foods. The uptake and distribution of Se, changes in Se content, and effects of various concentrations of Se in two forms (sodium selenite and sodium selenate) on sunflower and maize plants were measured in nutrient solution experiments. Results revealed the Se content in shoots and roots of both sunflower and maize plants significantly increased as the Se level increased. In this study, the highest exposure concentrations (30 and 90 mg/L, respectively) caused toxicity in both sunflower and maize. While both Se forms damaged and inhibited plant growth, each behaved differently, as toxicity due to selenite was observed more than in the selenate treatments. Sunflower demonstrated a high Se accumulation capacity, with higher translocation of selenate from roots to shoots compared with selenite. Since in seleniferous soils, a high change in plants' capability exists to uptake Se from these soils and also most of the cultivated crop plants have a bit tolerance to high Se levels, distinction of plants with different Se tolerance is important. This study has tried to discuss about it.

Assessment of Climate Suitability of Maize in South Korea

Science.gov (United States)

Hyun, S.; Choi, D.; Seo, B.

2017-12-01

Assessing suitable areas for crops would be useful to design alternate cropping systems as an adaptation option to climate change adaptation. Although suitable areas could be identified by using a crop growth model, it would require a number of input parameters including cultivar and soil. Instead, a simple climate suitability model, e.g., EcoCrop model, could be used for an assessment of climate suitability for a major grain crop. The objective of this study was to assess of climate suitability for maize using the EcoCrop model under climate change conditions in Korea. A long term climate data from 2000 - 2100 were compiled from weather data source. The EcoCrop model implemented in R was used to determine climate suitability index at each grid cell. Overall, the EcoCrop model tended to identify suitable areas for maize production near the coastal areas whereas the actual major production areas located in inland areas. It is likely that the discrepancy between assessed and actual crop production areas would result from the socioeconomic aspects of maize production. Because the price of maize is considerably low, maize has been grown in an area where moisture and temperature conditions would be less than optimum. In part, a simple algorithm to predict climate suitability for maize would caused a relatively large error in climate suitability assessment under the present climate conditions. In 2050s, the climate suitability for maize increased in a large areas in southern and western part of Korea. In particular, the plain areas near the coastal region had considerably greater suitability index in the future compared with mountainous areas. The expansion of suitable areas for maize would help crop production policy making such as the allocation of rice production area for other crops due to considerably less demand for the rice in Korea.

Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

OpenAIRE

Buddhi Bahadur Achhami; Santa Bahadur BK; Ghana Shyam Bhandari

2015-01-01

Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage per...

Risk Adjusted Production Efficiency of Maize Farmers in Ethiopia: Implication for Improved Maize Varieties Adoption

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Sisay Diriba Lemessa

2017-09-01

Full Text Available This study analyzes the technical efficiency and production risk of 862 maize farmers in major maize producing regions of Ethiopia. It employs the stochastic frontier approach (SFA to estimate the level of technical efficiencies of stallholder farmers. The stochastic frontier approach (SFA uses flexible risk properties to account for production risk. Thus, maize production variability is assessed from two perspectives, the production risk and the technical efficiency. The study also attempts to determine the socio-economic and farm characteristics that influence technical efficiency of maize production in the study area. The findings of the study showed the existence of both production risk and technical inefficiency in maize production process. Input variables (amounts per hectare such as fertilizer and labor positively influence maize output. The findings also show that farms in the study area exhibit decreasing returns to scale. Fertilizer and ox plough days reduce output risk while labor and improved seed increase output risk. The mean technical efficiency for maize farms is 48 percent. This study concludes that production risk and technical inefficiency prevents the maize farmers from realizing their frontier output. The best factors that improve the efficiency of the maize farmers in the study area include: frequency of extension contact, access to credit and use of intercropping. It was also realized that altitude and terracing in maize farms had influence on farmer efficiency.

Principles of cancer cell culture.

Science.gov (United States)

Cree, Ian A

2011-01-01

The basics of cell culture are now relatively common, though it was not always so. The pioneers of cell culture would envy our simple access to manufactured plastics, media and equipment for such studies. The prerequisites for cell culture are a well lit and suitably ventilated laboratory with a laminar flow hood (Class II), CO(2) incubator, benchtop centrifuge, microscope, plasticware (flasks and plates) and a supply of media with or without serum supplements. Not only can all of this be ordered easily over the internet, but large numbers of well-characterised cell lines are available from libraries maintained to a very high standard allowing the researcher to commence experiments rapidly and economically. Attention to safety and disposal is important, and maintenance of equipment remains essential. This chapter should enable researchers with little prior knowledge to set up a suitable laboratory to do basic cell culture, but there is still no substitute for experience within an existing well-run laboratory.

Bacterial cell culture

OpenAIRE

sprotocols

2014-01-01

### Materials 1. Glass culture tubes with metal caps and labels - Growth medium, from media room or customized - Glass pipette tubes - Parafilm ### Equipment 1. Vortexer - Fireboy or Bunsen burner - Motorized pipette - Micropipettes and sterile tips ### Procedure For a typical liquid culture, use 5 ml of appropriate medium. The amount in each tube does not have to be exact if you are just trying to culture cells for their precious DNA. 1. Streak an a...

Replication of cultured lung epithelial cells

International Nuclear Information System (INIS)

Guzowski, D.; Bienkowski, R.

1986-01-01

The authors have investigated the conditions necessary to support replication of lung type 2 epithelial cells in culture. Cells were isolated from mature fetal rabbit lungs (29d gestation) and cultured on feeder layers of mitotically inactivated 3T3 fibroblasts. The epithelial nature of the cells was demonstrated by indirect immunofluorescent staining for keratin and by polyacid dichrome stain. Ultrastructural examination during the first week showed that the cells contained myofilaments, microvilli and lamellar bodies (markers for type 2 cells). The following changes were observed after the first week: increase in cell size; loss of lamellar bodies and appearance of multivesicular bodies; increase in rough endoplasmic reticulum and golgi; increase in tonafilaments and well-defined junctions. General cell morphology was good for up to 10 wk. Cells cultured on plastic surface degenerated after 1 wk. Cell replication was assayed by autoradiography of cultures exposed to ( 3 H)-thymidine and by direct cell counts. The cells did not replicate during the first week; however, between 2-10 wk the cells incorporated the label and went through approximately 6 population doublings. They have demonstrated that lung alveolar epithelial cells can replicate in culture if they are maintained on an appropriate substrate. The coincidence of ability to replicate and loss of markers for differentiation may reflect the dichotomy between growth and differentiation commonly observed in developing systems

Reversible gelling culture media for in-vitro cell culture in three-dimensional matrices

Science.gov (United States)

An, Yuehuei H.; Mironov, Vladimir A.; Gutowska, Anna

2000-01-01

A gelling cell culture medium useful for forming a three dimensional matrix for cell culture in vitro is prepared by copolymerizing an acrylamide derivative with a hydrophilic comonomer to form a reversible (preferably thermally reversible) gelling linear random copolymer in the form of a plurality of linear chains having a plurality of molecular weights greater than or equal to a minimum gelling molecular weight cutoff, mixing the copolymer with an aqueous solvent to form a reversible gelling solution and adding a cell culture medium to the gelling solution to form the gelling cell culture medium. Cells such as chondrocytes or hepatocytes are added to the culture medium to form a seeded culture medium, and temperature of the medium is raised to gel the seeded culture medium and form a three dimensional matrix containing the cells. After propagating the cells in the matrix, the cells may be recovered by lowering the temperature to dissolve the matrix and centrifuging.

Crystallization and preliminary X-ray diffraction analysis of maize aldose reductase

Energy Technology Data Exchange (ETDEWEB)

Kiyota, Eduardo [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil); Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas-SP (Brazil); Sousa, Sylvia Morais de [Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas-SP (Brazil); Santos, Marcelo Leite dos; Costa Lima, Aline da [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil); Menossi, Marcelo [Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas-SP (Brazil); Yunes, José Andrés [Laboratório de Biologia Molecular, Centro Infantil Boldrini, Campinas-SP (Brazil); Aparicio, Ricardo, E-mail: aparicio@iqm.unicamp.br [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil)

2007-11-01

Preliminary X-ray diffraction studies of apo maize aldose reductase at 2.0 Å resolution are reported. Maize aldose reductase (AR) is a member of the aldo-keto reductase superfamily. In contrast to human AR, maize AR seems to prefer the conversion of sorbitol into glucose. The apoenzyme was crystallized in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 47.2, b = 54.5, c = 100.6 Å and one molecule in the asymmetric unit. Synchrotron X-ray diffraction data were collected and a final resolution limit of 2.0 Å was obtained after data reduction. Phasing was carried out by an automated molecular-replacement procedure and structural refinement is currently in progress. The refined structure is expected to shed light on the functional/enzymatic mechanism and the unusual activities of maize AR.

Crystallization and preliminary X-ray diffraction analysis of maize aldose reductase

International Nuclear Information System (INIS)

Kiyota, Eduardo; Sousa, Sylvia Morais de; Santos, Marcelo Leite dos; Costa Lima, Aline da; Menossi, Marcelo; Yunes, José Andrés; Aparicio, Ricardo

2007-01-01

Preliminary X-ray diffraction studies of apo maize aldose reductase at 2.0 Å resolution are reported. Maize aldose reductase (AR) is a member of the aldo-keto reductase superfamily. In contrast to human AR, maize AR seems to prefer the conversion of sorbitol into glucose. The apoenzyme was crystallized in space group P2 1 2 1 2 1 , with unit-cell parameters a = 47.2, b = 54.5, c = 100.6 Å and one molecule in the asymmetric unit. Synchrotron X-ray diffraction data were collected and a final resolution limit of 2.0 Å was obtained after data reduction. Phasing was carried out by an automated molecular-replacement procedure and structural refinement is currently in progress. The refined structure is expected to shed light on the functional/enzymatic mechanism and the unusual activities of maize AR

Traditional and Modern Cell Culture in Virus Diagnosis.

Science.gov (United States)

Hematian, Ali; Sadeghifard, Nourkhoda; Mohebi, Reza; Taherikalani, Morovat; Nasrolahi, Abbas; Amraei, Mansour; Ghafourian, Sobhan

2016-04-01

Cell cultures are developed from tissue samples and then disaggregated by mechanical, chemical, and enzymatic methods to extract cells suitable for isolation of viruses. With the recent advances in technology, cell culture is considered a gold standard for virus isolation. This paper reviews the evolution of cell culture methods and demonstrates why cell culture is a preferred method for identification of viruses. In addition, the advantages and disadvantages of both traditional and modern cell culture methods for diagnosis of each type of virus are discussed. Detection of viruses by the novel cell culture methods is considered more accurate and sensitive. However, there is a need to include some more accurate methods such as molecular methods in cell culture for precise identification of viruses.

Application of cell co-culture system to study fat and muscle cells.

Science.gov (United States)

Pandurangan, Muthuraman; Hwang, Inho

2014-09-01

Animal cell culture is a highly complex process, in which cells are grown under specific conditions. The growth and development of these cells is a highly unnatural process in vitro condition. Cells are removed from animal tissues and artificially cultured in various culture vessels. Vitamins, minerals, and serum growth factors are supplied to maintain cell viability. Obtaining result homogeneity of in vitro and in vivo experiments is rare, because their structure and function are different. Living tissues have highly ordered complex architecture and are three-dimensional (3D) in structure. The interaction between adjacent cell types is quite distinct from the in vitro cell culture, which is usually two-dimensional (2D). Co-culture systems are studied to analyze the interactions between the two different cell types. The muscle and fat co-culture system is useful in addressing several questions related to muscle modeling, muscle degeneration, apoptosis, and muscle regeneration. Co-culture of C2C12 and 3T3-L1 cells could be a useful diagnostic tool to understand the muscle and fat formation in animals. Even though, co-culture systems have certain limitations, they provide a more realistic 3D view and information than the individual cell culture system. It is suggested that co-culture systems are useful in evaluating the intercellular communication and composition of two different cell types.

Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky) in storage condition

OpenAIRE

Ram B Paneru; Resham B Thapa

2017-01-01

The maize weevil (Sitophilus zeamais Motschulsky) is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD) with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C). The fin...

Exploring karyotype diversity of Argentinian Guaraní maize landraces: Relationship among South American maize.

Directory of Open Access Journals (Sweden)

María Florencia Realini

Full Text Available In Argentina there are two different centers of maize diversity, the Northeastern (NEA and the Northwestern (NWA regions of the country. In NEA, morphological studies identified 15 landraces cultivated by the Guaraní communities in Misiones Province. In the present study we analyzed the karyotype diversity of 20 populations of Guaraní maize landraces through classical and molecular cytogenetic analyses. Our results demonstrate significant intra and inter-populational variation in the percentage, number, size, chromosome position and frequencies of the heterochromatic blocks, which are called knobs. Knob sequence analysis (180-bp and TR-1 did not show significant differences among Guaraní populations. B chromosomes were not detected, and abnormal 10 (AB10 chromosomes were found with low frequency (0.1≥f ≤0.40 in six populations. Our results allowed karyotypic characterization of each analyzed population, defining for the first time the chromosomal constitution of maize germplasm from NEA. The multivariate analysis (PCoA and UPGMA of karyotype parameters allowed the distinction between two populations groups: the Popcorn and the Floury maize populations. These results are in agreement with previously published microsatellite and morphological/phenological studies. Finally, we compared our karyotype results with those previously reported for NWA and Central Region of South America maize. Our data suggest that there are important differences between maize from NEA and NWA at the karyotype level, supporting the hypothesis that there are two pathways of input of South America maize. Our results also confirm the existence of two centers of diversification of Argentinian native maize, NWA and NEA. This work contributes new knowledge about maize diversity, which is relevant for future plans to improve commercial maize, and for conservation of agrobiodiversity.

Differentiation of mammalian skeletal muscle cells cultured on microcarrier beads in a rotating cell culture system

Science.gov (United States)

Torgan, C. E.; Burge, S. S.; Collinsworth, A. M.; Truskey, G. A.; Kraus, W. E.

2000-01-01

The growth and repair of adult skeletal muscle are due in part to activation of muscle precursor cells, commonly known as satellite cells or myoblasts. These cells are responsive to a variety of environmental cues, including mechanical stimuli. The overall goal of the research is to examine the role of mechanical signalling mechanisms in muscle growth and plasticity through utilisation of cell culture systems where other potential signalling pathways (i.e. chemical and electrical stimuli) are controlled. To explore the effects of decreased mechanical loading on muscle differentiation, mammalian myoblasts are cultured in a bioreactor (rotating cell culture system), a model that has been utilised to simulate microgravity. C2C12 murine myoblasts are cultured on microcarrier beads in a bioreactor and followed throughout differentiation as they form a network of multinucleated myotubes. In comparison with three-dimensional control cultures that consist of myoblasts cultured on microcarrier beads in teflon bags, myoblasts cultured in the bioreactor exhibit an attenuation in differentiation. This is demonstrated by reduced immunohistochemical staining for myogenin and alpha-actinin. Western analysis shows a decrease, in bioreactor cultures compared with control cultures, in levels of the contractile proteins myosin (47% decrease, p < 0.01) and tropomyosin (63% decrease, p < 0.01). Hydrodynamic measurements indicate that the decrease in differentiation may be due, at least in part, to fluid stresses acting on the myotubes. In addition, constraints on aggregate size imposed by the action of fluid forces in the bioreactor affect differentiation. These results may have implications for muscle growth and repair during spaceflight.

Global maize production, utilization, and consumption.

Science.gov (United States)

Ranum, Peter; Peña-Rosas, Juan Pablo; Garcia-Casal, Maria Nieves

2014-04-01

Maize (Zea mays), also called corn, is believed to have originated in central Mexico 7000 years ago from a wild grass, and Native Americans transformed maize into a better source of food. Maize contains approximately 72% starch, 10% protein, and 4% fat, supplying an energy density of 365 Kcal/100 g and is grown throughout the world, with the United States, China, and Brazil being the top three maize-producing countries in the world, producing approximately 563 of the 717 million metric tons/year. Maize can be processed into a variety of food and industrial products, including starch, sweeteners, oil, beverages, glue, industrial alcohol, and fuel ethanol. In the last 10 years, the use of maize for fuel production significantly increased, accounting for approximately 40% of the maize production in the United States. As the ethanol industry absorbs a larger share of the maize crop, higher prices for maize will intensify demand competition and could affect maize prices for animal and human consumption. Low production costs, along with the high consumption of maize flour and cornmeal, especially where micronutrient deficiencies are common public health problems, make this food staple an ideal food vehicle for fortification. © 2014 New York Academy of Sciences. The World Health Organization retains copyright and all other rights in the manuscript of this article as submitted for publication.

Breeding of speciality maize for industrial purposes

OpenAIRE

Pajić Zorica; Radosavljević Milica; Filipović Milomir; Todorović Goran; Srdić Jelena; Pavlov Milovan

2010-01-01

The breeding programme on speciality maize with specific traits was established at the Maize Research Institute, Zemun Polje, several decades ago. The initial material was collected, new methods applying to breeding of speciality maize, i.e. popping maize, sweet maize and white-seeded maize, were introduced. The aim was to enhance and improve variability of the initial material for breeding these three types of maize. Then, inbred lines of good combining abilities were developed and used as c...

Assimilate unloading from maize (Zea mays L.) pedicel tissues

International Nuclear Information System (INIS)

Porter, G.A.; Knievel, D.P.; Shannon, J.C.

1987-01-01

Sugar and 14 C-assimilate release from the pedicel tissue of attached maize (Zea mays L.) kernels was studied following treatment with solute concentrations of up to 800 millimolal. Exposure and collection times ranged from 3 to 6 hours. Sugar and 14 C-assimilate unloading and collection in agar traps was reduced by 25 and 43%, respectively, following exposure to 800 millimolal mannitol. Inhibition of unloading was not specific to mannitol, since similar concentrations of glucose, fructose, or equimolar glucose plus fructose resulted in comparable inhibition. Ethylene glycol, a rapidly permeating solute which should not greatly influence cell turgor, did not inhibit 14 C-assimilate unloading. Based on these results, they suggest that inhibition of unloading by high concentrations of sugar or mannitol was due to reduced pedicel cell turgor. Changes in pedicel cell turgor may play a role in the regulation of assimilate transfer within the maize kernel

Aflatoxin levels in maize and maize products during the 2004 food ...

African Journals Online (AJOL)

Aflatoxin levels in maize and maize products during the 2004 food poisoning ... district were received at the National Public Health Laboratory Services (NPHLS). On analysis, they were found to be highly contaminated with aflatoxin B1.

Bioaccessibility of pro-vitamin A carotenoids is minimally affected by non pro-vitamin a xanthophylls in maize (Zea mays sp.).

Science.gov (United States)

Thakkar, Sagar K; Failla, Mark L

2008-12-10

The absorption of some carotenoids has been reported to be decreased by coingestion of relatively high concentrations of other carotenoids. It is unclear if such interactions occur among carotenoids during the digestion of plant foods. Current varieties of maize contain limited amounts of the pro-vitamin A (pro-VA) carotenoids beta-carotene (BC) and beta-cryptoxanthin (BCX) and relatively higher levels of their oxygenated metabolites lutein (LUT) and zeaxanthin (ZEA). Here, we examined if LUT and ZEA attenuate the bioaccessibility of pro-VA carotenoids at amounts and ratios present in maize. BC incorporation into bile salt mixed micelles during chemical preparation and during simulated small intestinal digestion of carotenoid-enriched oil was slightly increased when the concentration of LUT was sixfold or more greater than BC. Likewise, the efficiency of BC micellarization was slightly increased during simulated small intestinal digestion of white maize porridge supplemented with oil containing ninefold molar excess of LUT to BC. Mean efficiencies of micellarization of BC, BCX, LUT, and ZEA were 16.7, 27.7, 30.3, and 27.9%, respectively, and independent of the ratio of LUT plus ZEA to pro-VA carotenoids during simulated digestion of maize porridge prepared from flours containing 0.4-11.3 microg/g endogenous pro-VA carotenoids. LUT attenuated uptake of BC by differentiated cultures of Caco-2 human cells from medium-containing micelles in a dose-dependent manner with inhibition reaching 35% when the molar ratio of LUT to BC was 13. Taken together, these results suggest that the bioaccessibility of pro-VA carotenoids in maize is likely to be minimally affected by the relative levels of xanthophylls lacking pro-VA activity present in cultivars of maize.

Oscillating Cell Culture Bioreactor

Science.gov (United States)

Freed, Lisa E.; Cheng, Mingyu; Moretti, Matteo G.

2010-01-01

To better exploit the principles of gas transport and mass transport during the processes of cell seeding of 3D scaffolds and in vitro culture of 3D tissue engineered constructs, the oscillatory cell culture bioreactor provides a flow of cell suspensions and culture media directly through a porous 3D scaffold (during cell seeding) and a 3D construct (during subsequent cultivation) within a highly gas-permeable closed-loop tube. This design is simple, modular, and flexible, and its component parts are easy to assemble and operate, and are inexpensive. Chamber volume can be very low, but can be easily scaled up. This innovation is well suited to work with different biological specimens, particularly with cells having high oxygen requirements and/or shear sensitivity, and different scaffold structures and dimensions. The closed-loop changer is highly gas permeable to allow efficient gas exchange during the cell seeding/culturing process. A porous scaffold, which may be seeded with cells, is fixed by means of a scaffold holder to the chamber wall with scaffold/construct orientation with respect to the chamber determined by the geometry of the scaffold holder. A fluid, with/without biological specimens, is added to the chamber such that all, or most, of the air is displaced (i.e., with or without an enclosed air bubble). Motion is applied to the chamber within a controlled environment (e.g., oscillatory motion within a humidified 37 C incubator). Movement of the chamber induces relative motion of the scaffold/construct with respect to the fluid. In case the fluid is a cell suspension, cells will come into contact with the scaffold and eventually adhere to it. Alternatively, cells can be seeded on scaffolds by gel entrapment prior to bioreactor cultivation. Subsequently, the oscillatory cell culture bioreactor will provide efficient gas exchange (i.e., of oxygen and carbon dioxide, as required for viability of metabolically active cells) and controlled levels of fluid

High bioavailablilty iron maize (Zea mays L.) developed through molecular breeding provides more absorbable iron in vitro (Caco-2 model) and in vivo (Gallus gallus)

Science.gov (United States)

2013-01-01

Background Iron (Fe) deficiency is the most common micronutrient deficiency worldwide. Iron biofortification is a preventative strategy that alleviates Fe deficiency by improving the amount of absorbable Fe in crops. In the present study, we used an in vitro digestion/Caco 2 cell culture model as the guiding tool for breeding and development of two maize (Zea mays L.) lines with contrasting Fe bioavailability (ie. Low and High). Our objective was to confirm and validate the in vitro results and approach. Also, to compare the capacities of our two maize hybrid varieties to deliver Fe for hemoglobin (Hb) synthesis and to improve the Fe status of Fe deficient broiler chickens. Methods We compared the Fe-bioavailability between these two maize varieties with the presence or absence of added Fe in the maize based-diets. Diets were made with 75% (w/w) maize of either low or high Fe-bioavailability maize, with or without Fe (ferric citrate). Chicks (Gallus gallus) were fed the diets for 6 wk. Hb, liver ferritin and Fe related transporter/enzyme gene-expression were measured. Hemoglobin maintenance efficiency (HME) and total body Hb Fe values were used to estimate Fe bioavailability from the diets. Results DMT-1, DcytB and ferroportin expressions were higher (P < 0.05) in the "Low Fe" group than in the "High Fe" group (no added Fe), indicating lower Fe status and adaptation to less Fe-bioavailability. At times, Hb concentrations (d 21,28,35), HME (d 21), Hb-Fe (as from d 14) and liver ferritin were higher in the "High Fe" than in the "Low Fe" groups (P < 0.05), indicating greater Fe absorption from the diet and improved Fe status. Conclusions We conclude that the High Fe-bioavailability maize contains more bioavailable Fe than the Low Fe-bioavailability maize, presumably due to a more favorable matrix for absorption. Maize shows promise for Fe biofortification; therefore, human trials should be conducted to determine the efficacy of consuming the high bioavailable

Yield evaluation of maize-bean intercropping in a semi-arid region ...

African Journals Online (AJOL)

Treatments included three cropping systems (sole maize, sole bean, and the intercrop) and two cultural practices, namely, row orientation (north-south row vs east-west row) and sowing date (November/December and January). Intercropping showed a higher yield advantage in terms of LER and EV compared to sole ...

Testicular Sertoli cells influence the proliferation and immunogenicity of co-cultured endothelial cells

International Nuclear Information System (INIS)

Fan, Ping; He, Lan; Pu, Dan; Lv, Xiaohong; Zhou, Wenxu; Sun, Yining; Hu, Nan

2011-01-01

Research highlights: → The proliferation of dramatic increased by co-cultured with Sertoli cells. → VEGF receptor-2 expression of ECs was up-regulated by co-cultured with Sertoli cells. → The MHC expression of ECs induced by INF-γ and IL-6, IL-8 and sICAM induced by TNF-α decreased respectively after co-cultured with Sertoli cells. → ECs co-cultured with Sertoli cells also didn't increase the stimulation index of spleen lymphocytes. -- Abstract: The major problem of the application of endothelial cells (ECs) in transplantation is the lack of proliferation and their immunogenicity. In this study, we co-cultured ECs with Sertoli cells to monitor whether Sertoli cells can influence the proliferation and immunogenicity of co-cultured ECs. Sertoli cells were isolated from adult testicular tissue. ECs were divided into the control group and the experimental group, which included three sub-groups co-cultured with 1 x 10 3 , 1 x 10 4 or 1 x 10 5 cell/ml of Sertoli cells. The growth and proliferation of ECs were observed microscopically, and the expression of vascular endothelial growth factor (VEGF) receptor-2 (KDR) was examined by Western blotting. In another experiment, ECs were divided into the control group, the single culture group and the co-culture group with the optimal concentration of Sertoli cells. After INF-γ and TNF-α were added to the culture medium, MHC II antigen expression was detected by immunofluorescence staining and western blotting; interleukin (IL)-6, IL-8 and soluble intercellular adhesion molecule (sICAM) were measured in the culture medium by ELISA. We demonstrated that 1 x 10 4 cell/ml Sertoli cells promoted the proliferation of co-cultured ECs more dramatically than that in other groups (P 4 cell/ml of the Sertoli cells was most effective in the up-regulation of KDR expression in the co-cultured ECs (P < 0.05). Sertoli cells can effectively suppress INF-γ-induced MHC II antigen expression in co-cultured ECs compared with single

In vitro digestibility of processed and fermented soya bean, cowpea and maize

NARCIS (Netherlands)

Kiers, J.L.; Nout, M.J.R.; Rombouts, F.M.

2000-01-01

Tropical legumes, ie soya bean and cowpea, were pre-treated and subsequently fermented using pure cultures of Rhizopus spp. Impact of soaking, cooking and fermentation of the legumes on their digestibility was determined using an in vitro digestion method. Processing of white maize included, amongst

Morphological Characterization and Determination of Aflatoxin-Production Potentials of Aspergillus flavus Isolated from Maize and Soil in Kenya

OpenAIRE

Matome Gabriel Thathana; Hunja Murage; Akebe Luther King Abia; Michael Pillay

2017-01-01

This study aimed at morphologically identifying Aspergillus flavus in soil and maize and at determining their aflatoxin-producing potentials. Five hundred and fourteen isolates obtained from maize and soil in Kenya were cultivated on Czapeck Dox Agar, Malt Extract Agar, Sabouraud Dextrose Agar, Potato Dextrose Agar, and Rose-Bengal Chloramphenicol Agar. Isolates were identified using macro-morphological characteristics. Micromorphological characteristics were determined using slide cultures. ...

Long-term culture and differentiation of porcine red bone marrow hematopoietic cells co-cultured with immortalized mesenchymal cells.

Science.gov (United States)

Garba, Abubakar; Acar, Delphine D; Roukaerts, Inge D M; Desmarets, Lowiese M B; Devriendt, Bert; Nauwynck, Hans J

2017-09-01

Mesenchymal cells are multipotent stromal cells with self-renewal, differentiation and immunomodulatory capabilities. We aimed to develop a co-culture model for differentiating hematopoietic cells on top of immortalized mesenchymal cells for studying interactions between hematopoietic and mesenchymal cells, useful for adequately exploring the therapeutic potential of mesenchymal cells. In this study, we investigated the survival, proliferation and differentiation of porcine red bone marrow hematopoietic cells co-cultured with immortalized porcine bone marrow mesenchymal cells for a period of five weeks. Directly after collection, primary porcine bone marrow mesenchymal cells adhered firmly to the bottom of the culture plates and showed a fibroblast-like appearance, one week after isolation. Upon immortalization, porcine bone marrow mesenchymal cells were continuously proliferating. They were positive for simian virus 40 (SV40) large T antigen and the mesenchymal cell markers CD44 and CD55. Isolated red bone marrow cells were added to these immortalized mesenchymal cells. Five weeks post-seeding, 92±6% of the red bone marrow hematopoietic cells were still alive and their number increased 3-fold during five weekly subpassages on top of the immortalized mesenchymal cells. The red bone marrow hematopoietic cells were originally small and round; later, the cells increased in size. Some of them became elongated, while others remained round. Tiny dendrites appeared attaching hematopoietic cells to the underlying immortalized mesenchymal cells. Furthermore, weekly differential-quick staining of the cells indicated the presence of monoblasts, monocytes, macrophages and lymphocytes in the co-cultures. At three weeks of co-culture, flow cytometry analysis showed an increased surface expression of CD172a, CD14, CD163, CD169, CD4 and CD8 up to 37±0.8%, 40±8%, 41±4%, 23±3% and 19±5% of the hematopoietic cells, respectively. In conclusion, continuous mesenchymal cell

Effects of juglone and lawsone on oxidative stress in maize coleoptile cells treated with IAA.

Science.gov (United States)

Kurtyka, Renata; Pokora, Wojciech; Tukaj, Zbigniew; Karcz, Waldemar

2016-01-01

Naphthoquinones are secondary metabolites widely distributed in nature and produced by bacteria, fungi and higher plants. Their biological activity may result from induction of oxidative stress, caused by redox cycling or direct interaction with cellular macromolecules, in which quinones act as electrophiles. The redox homeostasis is known as one of factors involved in auxin-mediated plant growth regulation. To date, however, little is known about the crosstalk between reactive oxygen species (ROS) produced by quinones and the plant growth hormone auxin (IAA). In this study, redox cycling properties of two naphthoquinones, juglone (5-hydroxy-1,4-naphthoquinone) and lawsone (2-hydroxy-1,4-naphthoquinone), were compared in experiments performed on maize coleoptile segments incubated with or without the addition of IAA. It was found that lawsone was much more effective than juglone in increasing both H 2 O 2 production and the activity of antioxidative enzymes (SOD, POX and CAT) in coleoptile cells, regardless of the presence of IAA. An increase in the activity of Cu/Zn-SOD isoenzymes induced by both naphthoquinones suggests that juglone- and lawsone-generated H 2 O 2 was primarily produced in the cytosolic and cell wall spaces. The cell potential to neutralize hydrogen peroxide, determined by POX and CAT activity, pointed to activity of catalase as the main enzymatic mechanism responsible for degradation of H 2 O 2 Therefore, we assumed that generation of H 2 O 2 , induced more efficiently by LW than JG, was the major factor accounting for differences in the toxicity of naphthoquinones in maize coleoptiles. The role of auxin in the process appeared negligible. Moreover, the results suggested that oxidative stress imposed by JG and LW was one of mechanisms of allelopathic action of the studied quinones in plants. © The Authors 2016. Published by Oxford University Press on behalf of the Annals of Botany Company.

3D Cell Culture in Alginate Hydrogels

Directory of Open Access Journals (Sweden)

Therese Andersen

2015-03-01

Full Text Available This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent, and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.

Screening of promising maize genotypes against maize weevil (Sitophilus zeamais Motschulky in storage condition

Directory of Open Access Journals (Sweden)

Ram B Paneru

2017-12-01

Full Text Available The maize weevil (Sitophilus zeamais Motschulsky is a serious pest of economic importance in stored grains. It causes major damage to stored maize grain thereby reducing its weight, quality and germination. An experiment was conducted in randomized complete block design (RCBD with 3 replications to screen 32 maize genotypes against maize weevil in no-choice and free-choice conditions at Entomology Division, Khumaltar, Lalitpur (Room temperature: Maximum 24-32°C and Minimum 18-27°C. The findings showed that the maize genotypes had different response to maize weevil damage ranging from susceptible to tolerance. The genotypes Manakamana-3, Lumle White POP Corn and Ganesh-2 showed their tolerance to S. zeamais as evidenced by lower number of weevil emerged/attracted, lower amount of grain debris release and lower proportion of bored grains, while the genotype ZM-627 was the most susceptible to weevil damage in both tests. The other remaining genotypes were intermediate types. This information is useful to improve grain protection in storage and varietal improvement/release program.

Aflatoxigenic Aspergillus flavus and Aspergillus parasiticus strains in Hungarian maize fields.

Science.gov (United States)

Sebők, Flóra; Dobolyi, Csaba; Zágoni, Dóra; Risa, Anita; Krifaton, Csilla; Hartman, Mátyás; Cserháti, Mátyás; Szoboszlay, Sándor; Kriszt, Balázs

2016-12-01

Due to the climate change, aflatoxigenic Aspergillus species and strains have appeared in several European countries, contaminating different agricultural commodities with aflatoxin. Our aim was to screen the presence of aflatoxigenic fungi in maize fields throughout the seven geographic regions of Hungary. Fungi belonging to Aspergillus section Flavi were isolated in the ratio of 26.9% and 42.3% from soil and maize samples in 2013, and these ratios decreased to 16.1% and 34.7% in 2014. Based on morphological characteristics and the sequence analysis of the partial calmodulin gene, all isolates proved to be Aspergillus flavus, except four strains, which were identified as Aspergillus parasiticus. About half of the A. flavus strains and all the A. parasiticus strains were able to synthesize aflatoxins. Aflatoxigenic Aspergillus strains were isolated from all the seven regions of Hungary. A. parasiticus strains were found in the soil of the regions Southern Great Plain and Southern Transdanubia and in a maize sample of the region Western Transdanubia. In spite of the fact that aflatoxins have rarely been detected in feeds and foods in Hungary, aflatoxigenic A. flavus and A. parasiticus strains are present in the maize culture throughout Hungary posing a potential threat to food safety.

Coordination of the maize transcriptome by a conserved circadian clock

Directory of Open Access Journals (Sweden)

Harmon Frank G

2010-06-01

Full Text Available Abstract Background The plant circadian clock orchestrates 24-hour rhythms in internal physiological processes to coordinate these activities with daily and seasonal changes in the environment. The circadian clock has a profound impact on many aspects of plant growth and development, including biomass accumulation and flowering time. Despite recent advances in understanding the circadian system of the model plant Arabidopsis thaliana, the contribution of the circadian oscillator to important agronomic traits in Zea mays and other cereals remains poorly defined. To address this deficit, this study investigated the transcriptional landscape of the maize circadian system. Results Since transcriptional regulation is a fundamental aspect of circadian systems, genes exhibiting circadian expression were identified in the sequenced maize inbred B73. Of the over 13,000 transcripts examined, approximately 10 percent displayed circadian expression patterns. The majority of cycling genes had peak expression at subjective dawn and dusk, similar to other plant circadian systems. The maize circadian clock organized co-regulation of genes participating in fundamental physiological processes, including photosynthesis, carbohydrate metabolism, cell wall biogenesis, and phytohormone biosynthesis pathways. Conclusions Circadian regulation of the maize genome was widespread and key genes in several major metabolic pathways had circadian expression waveforms. The maize circadian clock coordinated transcription to be coincident with oncoming day or night, which was consistent with the circadian oscillator acting to prepare the plant for these major recurring environmental changes. These findings highlighted the multiple processes in maize plants under circadian regulation and, as a result, provided insight into the important contribution this regulatory system makes to agronomic traits in maize and potentially other C4 plant species.

Effect of x-ray irradiation on maize inbred line B73 tissue cultures and regenerated plants

International Nuclear Information System (INIS)

Wang, A.S.; Cheng, D.S.K.; Milcic, J.B.; Yang, T.C.

1988-01-01

In order to enhance variation induced by the tissue culture process and to obtain agronomically desirable mutants, friable embryogenic tissue cultures of maize (Zea mays L.) inbred line B73 were x-ray irradiated with 11 doses [0-8.4 kilorads (kR)]. Reductions in callus growth rate and embryogenic callus formation occurred with increasing x-ray doses 20 d and 3 months after irradiation. Callus irradiated with 0.8 kR showed a significant increase in growth rate and a 20% increase in embryogenic callus 9 months after irradiation. A total of 230 R 0 plants were regenerated for evaluation. Pollen fertility and seed set of R 0 plants decreased with increasing x-ray dosage. Days to anthesis and plant height of R 0 plants varied among x-ray treatments but were generally reduced with higher dosages. The number of chromosomal aberrations increased with x-ray dosage. The R 1 seeds taken from R 0 plants were also grown and tested for mutant segregation. Plants regenerated from irradiated calli had a two- to 10-fold increase in mutations over plants regenerated from unirradiated control callus. Germination frequency of seeds from R 0 plants decreased with increasing x-ray dosage. Although chlorophyll mutants were most frequently observed, a number of vigorous plants with earlier anthesis date were also recovered

Cell culture experiments planned for the space bioreactor

Science.gov (United States)

Morrison, Dennis R.; Cross, John H.

1987-01-01

Culturing of cells in a pilot-scale bioreactor remains to be done in microgravity. An approach is presented based on several studies of cell culture systems. Previous and current cell culture research in microgravity which is specifically directed towards development of a space bioprocess is described. Cell culture experiments planned for a microgravity sciences mission are described in abstract form.

Advances in cell culture: anchorage dependence

Science.gov (United States)

Merten, Otto-Wilhelm

2015-01-01

Anchorage-dependent cells are of great interest for various biotechnological applications. (i) They represent a formidable production means of viruses for vaccination purposes at very large scales (in 1000–6000 l reactors) using microcarriers, and in the last decade many more novel viral vaccines have been developed using this production technology. (ii) With the advent of stem cells and their use/potential use in clinics for cell therapy and regenerative medicine purposes, the development of novel culture devices and technologies for adherent cells has accelerated greatly with a view to the large-scale expansion of these cells. Presently, the really scalable systems—microcarrier/microcarrier-clump cultures using stirred-tank reactors—for the expansion of stem cells are still in their infancy. Only laboratory scale reactors of maximally 2.5 l working volume have been evaluated because thorough knowledge and basic understanding of critical issues with respect to cell expansion while retaining pluripotency and differentiation potential, and the impact of the culture environment on stem cell fate, etc., are still lacking and require further studies. This article gives an overview on critical issues common to all cell culture systems for adherent cells as well as specifics for different types of stem cells in view of small- and large-scale cell expansion and production processes. PMID:25533097

Effects of gamma radiation on maize samples contaminated with Fusarium verticillioides

International Nuclear Information System (INIS)

Ferreira-Castro, F.L.; Aquino, S.; Greiner, R.; Ribeiro, D.H.B.; Reis, T.A.; Correa, B.

2007-01-01

The efficacy of γ-irradiation as a method of decontamination of maize containing Fusarium verticillioides under controlled conditions of relative humidity (RH) (97.5%) and water activity has been studied. Maize grains inoculated with a spore suspension of F. verticillioides were irradiated to 2, 5, and 10 kGy. Thereafter, the irradiated and control samples were analyzed for the presence of fumonisins, their viable cells were counted, and their morphology was investigated by electronic microscopy. It was found possible to decrease the risk of exposure to fumonisins by irradiating maize to 5 or 10 kGy. However, at the dose of 2 kGy, the survived fungi (36%) can produce more fumonisins than the fungi in the control unirradiated samples under the same conditions

Study in situ of the water potential under a maize culture with a system of automatic measurement by a micropsychrometer with Peltier effect

International Nuclear Information System (INIS)

Valancogne, C.; Daudet, F.A.

1977-01-01

The use of micropsychrometers with Peltier effect and tensiometers made possible the study of the variations in soil matrix potential under a maize culture in space and time. The simultaneous measurement of the voluminal humidity through the neutron method enabled to observe the relatonship of the potential and the humidity. No significant hysteresis effect could be stated, but it appears that the extrapolation of the relationships of potential and humidity stated on soil samples under laboratory conditions to the field must be cautiously undertaken, which stresses the interest of knowing techniques for measuring directly matrix potential and humidity [fr

Absence of detectable transgenes in local landraces of maize in Oaxaca, Mexico (2003–2004)

Science.gov (United States)

Ortiz-García, S.; Ezcurra, E.; Schoel, B.; Acevedo, F.; Soberón, J.; Snow, A. A.

2005-01-01

In 2000, transgenes were detected in local maize varieties (landraces) in the mountains of Oaxaca, Mexico [Quist, D. & Chapela, I. H. (2001) Nature 414, 541–543]. This region is part of the Mesoamerican center of origin for maize (Zea mays L.), and the genetic diversity that is maintained in open-pollinated landraces is recognized as an important genetic resource of great cultural value. The presence of transgenes in landraces was significant because transgenic maize has never been approved for cultivation in Mexico. Here we provide a systematic survey of the frequency of transgenes in currently grown landraces. We sampled maize seeds from 870 plants in 125 fields and 18 localities in the state of Oaxaca during 2003 and 2004. We then screened 153,746 sampled seeds for the presence of two transgene elements from the 35S promoter of the cauliflower mosaic virus and the nopaline synthase gene (nopaline synthase terminator) from Agrobacterium tumefaciens. One or both of these transgene elements are present in all transgenic commercial varieties of maize. No transgenic sequences were detected with highly sensitive PCR-based markers, appropriate positive and negative controls, and duplicate samples for DNA extraction. We conclude that transgenic maize seeds were absent or extremely rare in the sampled fields. This study provides a much-needed preliminary baseline for understanding the biological, socioeconomic, and ethical implications of the inadvertent dispersal of transgenes from the United States and elsewhere to local landraces of maize in Mexico. PMID:16093316

Consumer preferences for maize products in urban Kenya.

Science.gov (United States)

De Groote, Hugo; Kimenju, Simon Chege

2012-06-01

New maize varieties have been biofortified with provitamin A, mainly a-carotene, which renders the grain yellow or orange. Unfortunately, many African consumers prefer white maize. The maize consumption patterns in Africa are, however, not known. To determine which maize products African consumers prefer to purchase and which maize preparations they prefer to eat. A survey of 600 consumers was conducted in Nairobi, Kenya, at three types of maize outlets: posho mills (small hammer mills), kiosks, and supermarkets. Clients of posho mills had lower incomes and less education than those of kiosks and supermarkets. The preferred maize product of the posho-mill clients was artisanal maize meal; the preferred product of the others was industrial maize meal. Maize is the preferred staple for lunch and dinner, eaten as a stiff porridge (ugali), followed by boiled maize and beans (githeri), regardless of socioeconomic background. For breakfast, only half the consumers prefer maize, mostly as a soft porridge (uji). This proportion is higher in low-income groups. Consumers show a strong preference for white maize over yellow, mostly for its organoleptic characteristics, and show less interest in biofortified maize. Maize is the major food staple in Nairobi, mostly eaten in a few distinct preparations. For biofortified yellow maize to be accepted, a strong public awareness campaign to inform consumers is needed, based on a sensory evaluation and the mass media, in particular on radio in the local language.

Suspension culture of pluripotent stem cells: effect of shear on stem cell fate.

Science.gov (United States)

Keller, Kevin C; Rodrigues, Beatriz; zur Nieden, Nicole I

2014-01-01

Despite significant promise, the routine usage of suspension cell culture to manufacture stem cell-derived differentiated cells has progressed slowly. Suspension culture is an innovative way of either expanding or differentiating cells and sometimes both are combined into a single bioprocess. Its advantages over static 2D culturing include a homogeneous and controllable culture environment and producing a large quantity of cells in a fraction of time. This feature makes suspension cell culture ideal for use in stem cell research and eventually ideal in the large-scale production of differentiated cells for regenerative medicine. Because of their tremendous differentiation capacities and unlimited growth properties, pluripotent stem cells (PSCs) in particular are considered potential sources for future cell-replacement therapies. Currently, expansion of PSCs is accomplished in 2D, which only permits a limited amount of cell growth per culture flask before cells need to be passaged. However, before stem cells can be applied clinically, several aspects of their expansion, such as directed growth, but also differentiation, need to be better controlled. This review will summarize recent advantages in suspension culture of PSCs, while at the same time highlighting current challenges.

Controlling the diversity of cell populations in a stem cell culture

NARCIS (Netherlands)

Heo, Inha; Clevers, Hans

2015-01-01

Culturing intestinal stem cells into 3D organoids results in heterogeneous cell populations, reflecting the in vivo cell type diversity. In a recent paper published in Nature, Wang et al. established a culture condition for a highly homogeneous population of intestinal stem cells.

The evolution of chicken stem cell culture methods.

Science.gov (United States)

Farzaneh, M; Attari, F; Mozdziak, P E; Khoshnam, S E

2017-12-01

1. The avian embryo is an excellent model for studying embryology and the production of pharmaceutical proteins in transgenic chickens. Furthermore, chicken stem cells have the potential for proliferation and differentiation and emerged as an attractive tool for various cell-based technologies. 2. The objective of these studies is the derivation and culture of these stem cells is the production of transgenic birds for recombinant biomaterials and vaccine manufacture, drug and cytotoxicity testing, as well as to gain insight into basic science, including cell tracking. 3. Despite similarities among the established chicken stem cell lines, fundamental differences have been reported between their culture conditions and applications. Recent conventional protocols used for expansion and culture of chicken stem cells mostly depend on feeder cells, serum-containing media and static culture. 4. Utilising chicken stem cells for generation of cell-based transgenic birds and a variety of vaccines requires large-scale cell production. However, scaling up the conventional adherent chicken stem cells is challenging and labour intensive. Development of a suspension cell culture process for chicken embryonic stem cells (cESCs), chicken primordial germ cells (PGCs) and chicken induced pluripotent stem cells (ciPSCs) will be an important advance for increasing the growth kinetics of these cells. 6. This review describes various approaches and suggestions to achieve optimal cell growth for defined chicken stem cells cultures and use in future manufacturing applications.

Transcriptome Analysis of Maize Immature Embryos Reveals the Roles of Cysteine in Improving Agrobacterium Infection Efficiency

Science.gov (United States)

Liu, Yan; Zhang, Zhiqiang; Fu, Junjie; Wang, Guoying; Wang, Jianhua; Liu, Yunjun

2017-01-01

Maize Agrobacterium-mediated transformation efficiency has been greatly improved in recent years. Antioxidants, such as, cysteine, can significantly improve maize transformation frequency through improving the Agrobacterium infection efficiency. However, the mechanism underlying the transformation improvement after cysteine exposure has not been elucidated. In this study, we showed that the addition of cysteine to the co-cultivation medium significantly increased the Agrobacterium infection efficiency of hybrid HiII and inbred line Z31 maize embryos. Reactive oxygen species contents were higher in embryos treated with cysteine than that without cysteine. We further investigated the mechanism behind cysteine-related infection efficiency increase using transcriptome analysis. The results showed that the cysteine treatment up-regulated 939 genes and down-regulated 549 genes in both Z31 and HiII. Additionally, more differentially expressed genes were found in HiII embryos than those in Z31 embryos, suggesting that HiII was more sensitive to the cysteine treatment than Z31. GO analysis showed that the up-regulated genes were mainly involved in the oxidation reduction process. The up-regulation of these genes could help maize embryos to cope with the oxidative stress stimulated by Agrobacterium infection. The down-regulated genes were mainly involved in the cell wall and membrane metabolism, such as, aquaporin and expansin genes. Decreased expression of these cell wall integrity genes could loosen the cell wall, thereby improving the entry of Agrobacterium into plant cells. This study offers insight into the role of cysteine in improving Agrobacterium-mediated transformation of maize immature embryos. PMID:29089955

Mammalian Cell Culture Simplified.

Science.gov (United States)

Moss, Robert; Solomon, Sondra

1991-01-01

A tissue culture experiment that does not require elaborate equipment and that can be used to teach sterile technique, the principles of animal cell line maintenance, and the concept of cell growth curves is described. The differences between cancerous and normal cells can be highlighted. The procedure is included. (KR)

Rabbit uterine epithelial cells: Co-culture with spermatozoa

International Nuclear Information System (INIS)

Boice, M.L.

1988-01-01

A primary culture of rabbit uterine epithelial cells was established and their effects on sperm function were examined in vitro. Epithelial cells were isolated from uteri of estrous rabbits and cultured on floating collagen gels in phenol red-free medium supplemented with 5% fetal bovine serum. Light microscopy and keratin staining showed that the epithelial cell population established in culture had morphological characteristics similar to that seen in the intact endometrium. Cells were cultured with 3 H-leucine and uptake of label by cells and its incorporation into cellular and secretory proteins determined. When compared to cells cultured for 24-48 h, incorporation of label into cellular protein was lower at 72-96 h, but secretion increased. Estradiol 17-β did not affect label uptake or incorporation, but did enhance proliferation of cells as judged by total DNA content of the cell population. Analysis of proteins in media by sodium dodecyl sulfate polyacrylamide gel electrophoresis and fluorography suggested that epithelial and stromal cells synthesis proteins that may be secretory in nature during 72-96 h culture. Twenty-nine to thirty-one h after initiation of epithelial cultures, 1-2 x 10 6 sperm were co-incubated with cells and sperm viability, motility, loss of acrosome and fertilizing ability determined

Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

Directory of Open Access Journals (Sweden)

Buddhi Bahadur Achhami

2015-12-01

Full Text Available Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage percentage by stem borer was up to 18.11%. Length of the feeding tunnel in maize stem was significantly higher in January than July. In case of exit holes made by borer counted more than four holes per plant that were planted in the month of January. All in all, except the tunnel length measurement per plant, we observed similar pattern in other borer damage parameters such as exit whole counts and plant damage percentage within the tested varieties. Stem borer damage was not significantly affect on grain yield.

X-ray microanalysis of single and cultured cells

International Nuclear Information System (INIS)

Wroblewski, J.; Roomans, G.M.

1984-01-01

X-ray microanalysis of single or cultured cells is often a useful alternative or complement to the analysis of the corresponding tissue. It also allows the analysis of individual cells in a cell population. Preparation for X-ray microanalysis poses a number of typical problems. Suspensions of single cells can be prepared by either of two pathways: (1) washing - mounting - drying, or (2) centrifugation - freezing or fixation - sectioning. The washing step in the preparation of single or cultured cells presents the most severe problems. Cultured cells are generally grown on a substrate that is compatible with both the analysis and the culture, washed and dried. In some cases, sectioning of cultured cell monolayers has been performed. Special problems in quantitative analysis occur in those cases where the cells are analyzed on a thick substrate, since the substrate contributes to the spectral background

Maize cob losses and their effects on the poverty status of maize

African Journals Online (AJOL)

This study analysed fresh maize cob losses and its effect on the poverty status of maize farmers in Edo State,. Nigeria. The specific .... is the poverty gap for ... Total cost. 162,367.48. 100.00. Returns. Total expected yield (N). 327,966.63. _.

MaizeGDB: The Maize Model Organism Database for Basic, Translational, and Applied Research

OpenAIRE

Lawrence, Carolyn J.; Harper, Lisa C.; Schaeffer, Mary L.; Sen, Taner Z.; Seigfried, Trent E.; Campbell, Darwin A.

2008-01-01

In 2001 maize became the number one production crop in the world with the Food and Agriculture Organization of the United Nations reporting over 614 million tonnes produced. Its success is due to the high productivity per acre in tandem with a wide variety of commercial uses. Not only is maize an excellent source of food, feed, and fuel, but also its by-products are used in the production of various commercial products. Maize's unparalleled success in agriculture stems from basic research, th...

Genetic resources in maize breeding

Directory of Open Access Journals (Sweden)

Anđelković Violeta

2017-01-01

Full Text Available Maize, wheat and rice are the most important cereals grown in the world. It is predicted that by 2025 maize is likely to become the crop with the greatest production globally. Conservation of maize germplasm provides the main resources for increased food and feed production. Conservation in gene banks (ex-situ is dominant strategy for maize conservation. More than 130 000 maize accessions, e.g. about 40% of total number, are stored in ten largest gene banks worldwide and Maize Research Institute Zemun Polje (MRIZP gene bank, with about 6000 accessions, is among them. Organized collecting missions started in 1961. in the former Yugoslavian territory, and up today, more than 2000 local maize landraces were stored. Pre-breeding activities that refer to identification of desirable traits from unadapted germplasm within genebank, result in materials expected to be included in breeding programs. Successful examples are LAMP, GEM and GENRES projects. At the end of XX century, at MRIZP genebank two pre-breeding activities were undertaken: eco-core and elite-core collections were created and landraces fulfilled particular criteria were chosen. In the last decade, MRIZP genebank collection was used for identification of sources for drought tolerance and improved grain quality. According to agronomic traits and general combining ability, two mini-core collections were created and included in commercial breeding programs.

Particle Trajectories in Rotating Wall Cell Culture Devices

Science.gov (United States)

Ramachandran N.; Downey, J. P.

1999-01-01

Cell cultures are extremely important to the medical community since such cultures provide an opportunity to perform research on human tissue without the concerns inherent in experiments on individual humans. Development of cells in cultures has been found to be greatly influenced by the conditions of the culture. Much work has focused on the effect of the motions of cells in the culture relative to the solution. Recently rotating wall vessels have been used with success in achieving improved cellular cultures. Speculation and limited research have focused on the low shear environment and the ability of rotating vessels to keep cells suspended in solution rather than floating or sedimenting as the primary reasons for the improved cellular cultures using these devices. It is widely believed that the cultures obtained using a rotating wall vessel simulates to some degree the effect of microgravity on cultures. It has also been speculated that the microgravity environment may provide the ideal acceleration environment for culturing of cellular tissues due to the nearly negligible levels of sedimentation and shear possible. This work predicts particle trajectories of cells in rotating wall vessels of cylindrical and annular design consistent with the estimated properties of typical cellular cultures. Estimates of the shear encountered by cells in solution and the interactions with walls are studied. Comparisons of potential experiments in ground and microgravity environments are performed.

Maize lethal necrosis (MLN), an emerging threat to maize-based food security in sub-Saharan Africa

Science.gov (United States)

In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on...

Usability and Applicability of Microfluidic Cell Culture Systems

DEFF Research Database (Denmark)

Hemmingsen, Mette

possibilities for, for example, precise control of the chemical environment, 3D cultures, controlled co-culture of different cell types or automated, individual control of up to 96 cell culture chambers in one integrated system. Despite the great new opportunities to perform novel experimental designs......Microfluidic cell culture has been a research area with great attention the last decade due to its potential to mimic the in vivo cellular environment more closely compared to what is possible by conventional cell culture methods. Many exciting and complex devices have been presented providing......, these devices still lack general implementation into biological research laboratories. In this project, the usability and applicability of microfluidic cell culture systems have been investigated. The tested systems display good properties regarding optics and compatibility with standard laboratory equipment...

Putting the Function in Maize Genomics

Directory of Open Access Journals (Sweden)

Stephen P. Moose

2009-07-01

Full Text Available The 51st Maize Genetics Conference was held March 12–15, 2009 at Pheasant Run Resort in St. Charles, Illinois. Nearly 500 attendees participated in a scientific program (available at covering a wide range of topics which integrate the rich biology of maize with recent discoveries in our understanding of the highly dynamic maize genome. Among the many research themes highlighted at the conference, the historical emphasis on studying the tremendous phenotypic diversity of maize now serves as the foundation for maize as a leading experimental system to characterize the mechanisms that generate variation in complex plant genomes and associate evolutionary change with phenotypes of interest.

Good Cell Culture Practice for stem cells and stem-cell-derived models.

Science.gov (United States)

Pamies, David; Bal-Price, Anna; Simeonov, Anton; Tagle, Danilo; Allen, Dave; Gerhold, David; Yin, Dezhong; Pistollato, Francesca; Inutsuka, Takashi; Sullivan, Kristie; Stacey, Glyn; Salem, Harry; Leist, Marcel; Daneshian, Mardas; Vemuri, Mohan C; McFarland, Richard; Coecke, Sandra; Fitzpatrick, Suzanne C; Lakshmipathy, Uma; Mack, Amanda; Wang, Wen Bo; Yamazaki, Daiju; Sekino, Yuko; Kanda, Yasunari; Smirnova, Lena; Hartung, Thomas

2017-01-01

The first guidance on Good Cell Culture Practice (GCCP) dates back to 2005. This document expands this to include aspects of quality assurance for in vitro cell culture focusing on the increasingly diverse cell types and culture formats used in research, product development, testing and manufacture of biotechnology products and cell-based medicines. It provides a set of basic principles of best practice that can be used in training new personnel, reviewing and improving local procedures, and helping to assure standard practices and conditions for the comparison of data between laboratories and experimentation performed at different times. This includes recommendations for the documentation and reporting of culture conditions. It is intended as guidance to facilitate the generation of reliable data from cell culture systems, and is not intended to conflict with local or higher level legislation or regulatory requirements. It may not be possible to meet all recommendations in this guidance for practical, legal or other reasons. However, when it is necessary to divert from the principles of GCCP, the risk of decreasing the quality of work and the safety of laboratory staff should be addressed and any conclusions or alternative approaches justified. This workshop report is considered a first step toward a revised GCCP 2.0.

Long-term maintenance of human induced pluripotent stem cells by automated cell culture system.

Science.gov (United States)

Konagaya, Shuhei; Ando, Takeshi; Yamauchi, Toshiaki; Suemori, Hirofumi; Iwata, Hiroo

2015-11-17

Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem (iPS) cells, are regarded as new sources for cell replacement therapy. These cells can unlimitedly expand under undifferentiated conditions and be differentiated into multiple cell types. Automated culture systems enable the large-scale production of cells. In addition to reducing the time and effort of researchers, an automated culture system improves the reproducibility of cell cultures. In the present study, we newly designed a fully automated cell culture system for human iPS maintenance. Using an automated culture system, hiPS cells maintained their undifferentiated state for 60 days. Automatically prepared hiPS cells had a potency of differentiation into three germ layer cells including dopaminergic neurons and pancreatic cells.

High-Throughput Cancer Cell Sphere Formation for 3D Cell Culture.

Science.gov (United States)

Chen, Yu-Chih; Yoon, Euisik

2017-01-01

Three-dimensional (3D) cell culture is critical in studying cancer pathology and drug response. Though 3D cancer sphere culture can be performed in low-adherent dishes or well plates, the unregulated cell aggregation may skew the results. On contrary, microfluidic 3D culture can allow precise control of cell microenvironments, and provide higher throughput by orders of magnitude. In this chapter, we will look into engineering innovations in a microfluidic platform for high-throughput cancer cell sphere formation and review the implementation methods in detail.

Liver Cell Culture Devices

NARCIS (Netherlands)

Andria, B.; Bracco, A.; Cirino, G.; Chamuleau, R. A. F. M.

2010-01-01

In the last 15 years many different liver cell culture devices, consisting of functional liver cells and artificial materials, have been developed. They have been devised for numerous different applications, such as temporary organ replacement (a bridge to liver transplantation or native liver

Characterization of glucocerebrosidase in peripheral blood cells and cultured blastoid cells

NARCIS (Netherlands)

Aerts, J. M.; Heikoop, J.; van Weely, S.; Donker-Koopman, W. E.; Barranger, J. A.; Tager, J. M.; Schram, A. W.

1988-01-01

We have characterized glucocerebrosidase in various cell types of peripheral blood of control subjects and in cultured human blastoid cells. The intracellular level of glucocerebrosidase in cultured blastoid cells (10-30 nmol substrate hydrolyzed/h.mg protein) resembles closely values observed for

Biosynthesis of 14C-phytoene from tomato cell suspension cultures (Lycopersicon esculentum) for utilization in prostate cancer cell culture studies.

Science.gov (United States)

Campbell, Jessica K; Rogers, Randy B; Lila, Mary Ann; Erdman, John W

2006-02-08

This work describes the development and utilization of a plant cell culture production approach to biosynthesize and radiolabel phytoene and phytofluene for prostate cancer cell culture studies. The herbicide norflurazon was added to established cell suspension cultures of tomato (Lycopersicon esculentum cv. VFNT cherry), to induce the biosynthesis and accumulation of the lycopene precursors, phytoene and phytofluene, in their natural isomeric forms (15-cis-phytoene and two cis-phytofluene isomers). Norflurazon concentrations, solvent carrier type and concentration, and duration of culture exposure to norflurazon were screened to optimize phytoene and phytofluene synthesis. Maximum yields of both phytoene and phytofluene were achieved after 7 days of treatment with 0.03 mg norflurazon/40 mL fresh medium, provided in 0.07% solvent carrier. Introduction of 14C-sucrose to the tomato cell culture medium enabled the production of 14C-labeled phytoene for subsequent prostate tumor cell uptake studies. In DU 145 prostate tumor cells, it was determined that 15-cis-phytoene and an oxidized product of phytoene were taken up and partially metabolized by the cells. The ability to biosynthesize, radiolabel, and isolate these carotenoids from tomato cell cultures is a novel, valuable methodology for further in vitro and in vivo investigations into the roles of phytoene and phytofluene in cancer chemoprevention.

Advantages and challenges of microfluidic cell culture in polydimethylsiloxane devices.

Science.gov (United States)

Halldorsson, Skarphedinn; Lucumi, Edinson; Gómez-Sjöberg, Rafael; Fleming, Ronan M T

2015-01-15

Culture of cells using various microfluidic devices is becoming more common within experimental cell biology. At the same time, a technological radiation of microfluidic cell culture device designs is currently in progress. Ultimately, the utility of microfluidic cell culture will be determined by its capacity to permit new insights into cellular function. Especially insights that would otherwise be difficult or impossible to obtain with macroscopic cell culture in traditional polystyrene dishes, flasks or well-plates. Many decades of heuristic optimization have gone into perfecting conventional cell culture devices and protocols. In comparison, even for the most commonly used microfluidic cell culture devices, such as those fabricated from polydimethylsiloxane (PDMS), collective understanding of the differences in cellular behavior between microfluidic and macroscopic culture is still developing. Moving in vitro culture from macroscopic culture to PDMS based devices can come with unforeseen challenges. Changes in device material, surface coating, cell number per unit surface area or per unit media volume may all affect the outcome of otherwise standard protocols. In this review, we outline some of the advantages and challenges that may accompany a transition from macroscopic to microfluidic cell culture. We focus on decisive factors that distinguish macroscopic from microfluidic cell culture to encourage a reconsideration of how macroscopic cell culture principles might apply to microfluidic cell culture. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Isolation and culture of larval cells from C. elegans.

Directory of Open Access Journals (Sweden)

Sihui Zhang

Full Text Available Cell culture is an essential tool to study cell function. In C. elegans the ability to isolate and culture cells has been limited to embryonically derived cells. However, cells or blastomeres isolated from mixed stage embryos terminally differentiate within 24 hours of culture, thus precluding post-embryonic stage cell culture. We have developed an efficient and technically simple method for large-scale isolation and primary culture of larval-stage cells. We have optimized the treatment to maximize cell number and minimize cell death for each of the four larval stages. We obtained up to 7.8×10(4 cells per microliter of packed larvae, and up to 97% of adherent cells isolated by this method were viable for at least 16 hours. Cultured larval cells showed stage-specific increases in both cell size and multinuclearity and expressed lineage- and cell type-specific reporters. The majority (81% of larval cells isolated by our method were muscle cells that exhibited stage-specific phenotypes. L1 muscle cells developed 1 to 2 wide cytoplasmic processes, while L4 muscle cells developed 4 to 14 processes of various thicknesses. L4 muscle cells developed bands of myosin heavy chain A thick filaments at the cell center and spontaneously contracted ex vivo. Neurons constituted less than 10% of the isolated cells and the majority of neurons developed one or more long, microtubule-rich protrusions that terminated in actin-rich growth cones. In addition to cells such as muscle and neuron that are high abundance in vivo, we were also able to isolate M-lineage cells that constitute less than 0.2% of cells in vivo. Our novel method of cell isolation extends C. elegans cell culture to larval developmental stages, and allows use of the wealth of cell culture tools, such as cell sorting, electrophysiology, co-culture, and high-resolution imaging of subcellular dynamics, in investigation of post-embryonic development and physiology.

ISOLATION AND IDENTIFICATION OF MICROORGANISMS DURING SPONTANEOUS FERMENTATION OF MAIZE [Isolasi dan Identifikasi Mikroorganisme pada Fermentasi Spontan Jagung

Directory of Open Access Journals (Sweden)

Rahmawati1,2

2013-06-01

Full Text Available Maize was traditionally the second most common staple food in Indonesia. Conversion to maize flour has been accomplished to improve its convenience. Traditionally, maize flour is produced by soaking the kernels in water followed by grinding. It was reported that final physicochemical characteristics of the maize flour were influenced by spontaneous fermentation which occurred during soaking. This research aimed to isolate and identify important microorganisms that grew during fermentation thus a standardized starter culture can be developed for a more controlled fermentation process. Soaking of maize grits was conducted in sterile water (grits:water=1:2, w/v in a closed container at room temperature (±28ºC for 72 hours. After 0, 4, 12, 24, 36, 48, 72 hours, water and maize grits were sampled and tested for the presence of mold, yeast, and lactic acid bacteria (LAB. Isolates obtained from the spontaneous fermentation were reinoculated into the appropriate media containing starch to observe their amylolytic activity. Individual isolate was then identified; mold by slide culture method, while yeast and LAB by biochemical rapid kits, i.e. API 20C AUX and API CH50, respectively. The number of each microorganism was plotted against time to obtain the growth curve of the microorganisms during spontaneous fermentation. The microorganisms were identified as Penicillium chrysogenum, P. citrinum, A. flavus, A. niger, Rhizopus stolonifer, R.oryzae, Fusarium oxysporum, Acremonium strictum, Candida famata, Kodamaea ohmeri, Candida krusei/incospicua, Lactobacillus plantarum 1a, Pediococcus pentosaceus, L. brevis 1, L. plantarum 1b, and L. paracasei ssp paracasei 3. Four molds and one yeast were amylolytic while none of the LAB was capable of starch hydrolysis. The growth curve suggested that the amylolitic mold and yeast grew to hydrolyze starch during the course of fermentation, while the LABs benefited from the hydrolyzed products and dominated the later

Identification of resistance to Maize rayado fino virus in maize inbred lines

Science.gov (United States)

Maize rayado fino virus (MRFV) is one of the most important virus diseases of maize in America. Severe yield losses, ranging from 10 to 50% in landraces to nearly 100% in contemporary cultivars, have been reported. Resistance has been reported in populations, but few inbred lines have been identifie...

Introducing Mammalian Cell Culture and Cell Viability Techniques in the Undergraduate Biology Laboratory.

Science.gov (United States)

Bowey-Dellinger, Kristen; Dixon, Luke; Ackerman, Kristin; Vigueira, Cynthia; Suh, Yewseok K; Lyda, Todd; Sapp, Kelli; Grider, Michael; Crater, Dinene; Russell, Travis; Elias, Michael; Coffield, V McNeil; Segarra, Verónica A

2017-01-01

Undergraduate students learn about mammalian cell culture applications in introductory biology courses. However, laboratory modules are rarely designed to provide hands-on experience with mammalian cells or teach cell culture techniques, such as trypsinization and cell counting. Students are more likely to learn about cell culture using bacteria or yeast, as they are typically easier to grow, culture, and manipulate given the equipment, tools, and environment of most undergraduate biology laboratories. In contrast, the utilization of mammalian cells requires a dedicated biological safety cabinet and rigorous antiseptic techniques. For this reason, we have devised a laboratory module and method herein that familiarizes students with common cell culture procedures, without the use of a sterile hood or large cell culture facility. Students design and perform a time-efficient inquiry-based cell viability experiment using HeLa cells and tools that are readily available in an undergraduate biology laboratory. Students will become familiar with common techniques such as trypsinizing cells, cell counting with a hemocytometer, performing serial dilutions, and determining cell viability using trypan blue dye. Additionally, students will work with graphing software to analyze their data and think critically about the mechanism of death on a cellular level. Two different adaptations of this inquiry-based lab are presented-one for non-biology majors and one for biology majors. Overall, these laboratories aim to expose students to mammalian cell culture and basic techniques and help them to conceptualize their application in scientific research.

Multizone Paper Platform for 3D Cell Cultures

Science.gov (United States)

Derda, Ratmir; Hong, Estrella; Mwangi, Martin; Mammoto, Akiko; Ingber, Donald E.; Whitesides, George M.

2011-01-01

In vitro 3D culture is an important model for tissues in vivo. Cells in different locations of 3D tissues are physiologically different, because they are exposed to different concentrations of oxygen, nutrients, and signaling molecules, and to other environmental factors (temperature, mechanical stress, etc). The majority of high-throughput assays based on 3D cultures, however, can only detect the average behavior of cells in the whole 3D construct. Isolation of cells from specific regions of 3D cultures is possible, but relies on low-throughput techniques such as tissue sectioning and micromanipulation. Based on a procedure reported previously (“cells-in-gels-in-paper” or CiGiP), this paper describes a simple method for culture of arrays of thin planar sections of tissues, either alone or stacked to create more complex 3D tissue structures. This procedure starts with sheets of paper patterned with hydrophobic regions that form 96 hydrophilic zones. Serial spotting of cells suspended in extracellular matrix (ECM) gel onto the patterned paper creates an array of 200 micron-thick slabs of ECM gel (supported mechanically by cellulose fibers) containing cells. Stacking the sheets with zones aligned on top of one another assembles 96 3D multilayer constructs. De-stacking the layers of the 3D culture, by peeling apart the sheets of paper, “sections” all 96 cultures at once. It is, thus, simple to isolate 200-micron-thick cell-containing slabs from each 3D culture in the 96-zone array. Because the 3D cultures are assembled from multiple layers, the number of cells plated initially in each layer determines the spatial distribution of cells in the stacked 3D cultures. This capability made it possible to compare the growth of 3D tumor models of different spatial composition, and to examine the migration of cells in these structures. PMID:21573103

Morphology of primary human venous endothelial cell cultures before and after culture medium exchange.

Science.gov (United States)

Krüger-Genge, A; Fuhrmann, R; Jung, F; Franke, R P

2015-01-01

The evaluation of the interaction of human, venous endothelial cells (HUVEC) with body foreign materials on the cellular level cannot be performed in vivo, but is investigated in vitro under standard culture conditions. To maintain the vitality, proliferation and morphology of HUVEC seeded on body foreign substrates over days, the cell culture medium is usually exchanged every second day. It is well known, that alterations in the microenvironment of cells bear the risk of influencing cell morphology and function. In the current study the influence of cell culture medium exchange on HUVEC cytoskeletal microfilament structure and function was investigated. HUVEC in the third passage were seeded on extracellular matrix (ECM) - which was secreted from bovine corneal endothelial cells on glass- until functional confluence was reached. The experiment started 11 days after HUVEC seeding with an exchange of the cell culture medium followed by a staining of the actin microfilaments with phalloidin-rhodamin 1.5 and 5 minutes after medium exchange. The microfilaments were documented by use of an Olympus microscope (IMT-2) equipped with a UV lamp and online connected to a TV chain (Sony XC 50 ST/monochrome) implying an OPTIMAS - Image analysis system. Prostacyclin was analysed in the cell culture supernatant. 1.5 min after culture medium exchange in the functionally confluent cultures a slight disturbance of the actin microfilament structure with a broadening of the marginal filament band, a partial disconnection of cell-cell contacts and the appearance of intercellular fenestrations were observed. 5 minutes after medium exchange a redevelopment of the slightly disturbed microfilament structure with a condensation and narrowing of the marginal filament band was seen. 12 h later a further consolidation of the microfilament structure occurred. In addition, a perturbation of the cultured HUVEC occurred after cell culture medium exchange. The prostacyclin concentration in the

Assessment of ptxD gene as an alternative selectable marker for Agrobacterium-mediated maize transformation.

Science.gov (United States)

Nahampun, Hartinio N; López-Arredondo, Damar; Xu, Xing; Herrera-Estrella, Luis; Wang, Kan

2016-05-01

Bacterial phosphite oxidoreductase gene and chemical phosphite can be used as a selection system for Agrobacterium -mediated maize transformation. Application of phosphite (Phi) on plants can interfere the plant metabolic system leading to stunted growth and lethality. On the other hand, ectopic expression of the ptxD gene in tobacco and Arabidopsis allowed plants to grow in media with Phi as the sole phosphorous source. The phosphite oxidoreductase (PTXD) enzyme catalyzes the conversion of Phi into phosphate (Pi) that can then be metabolized by plants and utilized as their essential phosphorous source. Here we assess an alternative selectable marker based on a bacterial ptxD gene for Agrobacterium-mediated maize transformation. We compared the transformation frequencies of maize using either the ptxD/Phi selection system or a standard herbicide bar/bialaphos selection system. Two maize genotypes, a transformation amenable hybrid Hi II and an inbred B104, were tested. Transgene presence, insertion copy numbers, and ptxD transcript levels were analyzed and compared. This work demonstrates that the ptxD/Phi selection system can be used for Agrobacterium-mediated maize transformation of both type I and type II callus culture and achieve a comparable frequency as that of the herbicide bar/bialaphos selection system.

PNL1 and PNL2 : Arabidopsis homologs of maize PAN1

OpenAIRE

Clark, Lauren Gail

2010-01-01

PNL1 and PNL2 are the closest Arabidopsis relatives of maize pan1. pan1 and the PNL family of 11 genes encode leucine-rich repeat, receptor-like kinases, however none of these putative kinases is predicted to have actual kinase function, due to one or more amino acid substitutions in residues necessary for kinase function. Because PAN1 plays a role in subsidiary cell formation in maize, it is hypothesized that PNL1 and PNL2 are involved in stomatal formation in Arabidopsis. YFP fusions of the...

Mutation in cultured mammalian cells

International Nuclear Information System (INIS)

Nakamura, N.; Okada, S.

1982-01-01

Mammalian cell cultures were exposed to gamma-rays at various dose rates. Dose-rate effects were observed in cultured somatic cells of the mouse for cell killing and mutations resistant to 6-thioguanine (TGsup(r)) and to methotrexate (MTXsup(r)). Linear quadratic model may be applied to cell killing and TGsup(r) mutations in some cases but can not explain the whole data. Results at low doses with far low dose-rate were not predictable from data at high doses with acute or chronic irradiation. Radioprotective effects of dimethyl sulfoxide were seen only after acute exposure but not after chronic one, suggesting that damages by indirect action of radiations may be potentially reparable by cells. TGsup(r) mutations seem to contain gross structural changes whereas MTXsup(r) ones may have smaller alterations. (Namekawa, K.)

Cell-free DNA in a three-dimensional spheroid cell culture model

DEFF Research Database (Denmark)

Aucamp, Janine; Calitz, Carlemi; Bronkhorst, Abel J.

2017-01-01

Background Investigating the biological functions of cell-free DNA (cfDNA) is limited by the interference of vast numbers of putative sources and causes of DNA release into circulation. Utilization of three-dimensional (3D) spheroid cell cultures, models with characteristics closer to the in vivo...... cultures can serve as effective, simplified in vivo-simulating “closed-circuit” models since putative sources of cfDNA are limited to only the targeted cells. In addition, cfDNA can also serve as an alternative or auxiliary marker for tracking spheroid growth, development and culture stability. Biological...... significance 3D cell cultures can be used to translate “closed-circuit” in vitro model research into data that is relevant for in vivo studies and clinical applications. In turn, the utilization of cfDNA during 3D culture research can optimize sample collection without affecting the stability of the growth...

Comparative diversity of arthropods on Bt maize and non-Bt maize in two different cropping systems in South Africa.

Science.gov (United States)

Truter, J; Van Hamburg, H; Van Den Berg, J

2014-02-01

The biodiversity of an agroecosystem is not only important for its intrinsic value but also because it influences ecological functions that are vital for crop production in sustainable agricultural systems and the surrounding environment. A concern about genetically modified (GM) crops is the potential negative impact that such crops could have on diversity and abundance of nontarget organisms, and subsequently on ecosystem functions. Therefore, it is essential to assess the potential environmental risk of the release of a GM crop and to study its effect on species assemblages within that ecosystem. Assessment of the impact of Bt maize on the environment is hampered by the lack of basic checklists of species present in maize agroecosystems. The aims of the study were to compile a checklist of arthropods that occur on maize in South Africa and to compare the diversity and abundance of arthropods and functional groups on Bt maize and non-Bt maize. Collections of arthropods were carried out during two growing seasons on Bt maize and non-Bt maize plants at two localities. Three maize fields were sampled per locality during each season. Twenty plants, each of Bt maize and non-Bt maize, were randomly selected from the fields at each site. The arthropods collected during this study were classified to morphospecies level and grouped into the following functional groups: detritivores, herbivores, predators, and parasitoids. Based on feeding strategy, herbivores and predators were further divided into sucking herbivores or predators (piercing-sucking mouthparts) and chewing herbivores or predators (chewing mouthparts). A total of 8,771 arthropod individuals, comprising 288 morphospecies and presenting 20 orders, were collected. Results from this short-term study indicated that abundance and diversity of arthropods in maize and the different functional guilds were not significantly affected by Bt maize, either in terms of diversity or abundance.

Effects of maize maturity at harvest and dietary proportion of maize silage on intake and performance of growing/finishing bulls

DEFF Research Database (Denmark)

Zaralis, K.; Nørgaard, P.; Helander, C.

2014-01-01

Whole-crop maize silage as forage in diets of finishing cattle can promote high intakes and thus, enhances animal performance. In the present study we evaluated the effect of whole-crop maize maturity at harvest and the proportion of maize-silage in diets of finishing bulls, on feed intake...... of treatments, involving two maturity stages of maize at harvest (i.e. dough stage or dent stage) and two maize silage proportions (i.e. 100% maize silage or 50% maize and 50% grass silage). The diets were offered ad libitum as total mixed rations (TMRs) with inclusion of concentrates (i.e. rolled barley; dried...... distillers’ grain plus soluble; cold-pressed rapeseed cake) in a 40% proportion on DM basis. All animals were slaughtered at a target body weight of 630 kg. Bulls fed on diets containing maize silage as sole forage achieved higher live-weight gain (P

Incidence of Fusarium spp. and Levels of Fumonisin B1 in Maize in Western Kenya

Science.gov (United States)

Kedera, C. J.; Plattner, R. D.; Desjardins, A. E.

1999-01-01

Maize kernel samples were collected in 1996 from smallholder farm storages in the districts of Bomet, Bungoma, Kakamega, Kericho, Kisii, Nandi, Siaya, Trans Nzoia, and Vihiga in the tropical highlands of western Kenya. Two-thirds of the samples were good-quality maize, and one-third were poor-quality maize with a high incidence of visibly diseased kernels. One hundred fifty-three maize samples were assessed for Fusarium infection by culturing kernels on a selective medium. The isolates obtained were identified to the species level based on morphology and on formation of the sexual stage in Gibberella fujikuroi mating population tests. Fusarium moniliforme (G. fujikuroi mating population A) was isolated most frequently, but F. subglutinans (G. fujikuroi mating population E), F. graminearum, F. oxysporum, F. solani, and other Fusarium species were also isolated. The high incidence of kernel infection with the fumonisin-producing species F. moniliforme indicated a potential for fumonisin contamination of Kenyan maize. However, analysis of 197 maize kernel samples by high-performance liquid chromatography found little fumonisin B1 in most of the samples. Forty-seven percent of the samples contained fumonisin B1 at levels above the detection limit (100 ng/g), but only 5% were above 1,000 ng/g, a proposed level of concern for human consumption. The four most-contaminated samples, with fumonisin B1 levels ranging from 3,600 to 11,600 ng/g, were from poor-quality maize collected in the Kisii district. Many samples with a high incidence of visibly diseased kernels contained little or no fumonisin B1, despite the presence of F. moniliforme. This result may be attributable to the inability of F. moniliforme isolates present in Kenyan maize to produce fumonisins, to the presence of other ear rot fungi, and/or to environmental conditions unfavorable for fumonisin production. PMID:9872757

Cell culture techniques in honey bee research

Science.gov (United States)

Cell culture techniques are indispensable in most if not all life science disciplines to date. Wherever cell culture models are lacking scientific development is hampered. Unfortunately this has been and still is the case in honey bee research because permanent honey bee cell lines have not yet been...

MEMS-based dynamic cell-to-cell culture platforms using electrochemical surface modifications

International Nuclear Information System (INIS)

Chang, Jiyoung; Lin, Liwei; Yoon, Sang-Hee; Mofrad, Mohammad R K

2011-01-01

MEMS-based biological platforms with the capability of both spatial placements and time releases of living cells for cell-to-cell culture experiments have been designed and demonstrated utilizing electrochemical surface modification effects. The spatial placement is accomplished by electrochemical surface modification of substrate surfaces to be either adhesive or non-adhesive for living cells. The time control is achieved by the electrical activation of the selective indium tin oxide co-culture electrode to allow the migration of living cells onto the electrode to start the cell-to-cell culture studies. Prototype devices have a three-electrode design with an electrode size of 50 × 50 µm 2 and the separation gaps of 2 µm between them. An electrical voltage of −1.5 V has been used to activate the electrodes independently and sequentially to demonstrate the dynamic cell-to-cell culture experiments of NIH 3T3 fibroblast and Madin Darby canine kidney cells. As such, this MEMS platform could be a basic yet versatile tool to characterize transient cell-to-cell interactions

Microfluidic engineered high cell density three-dimensional neural cultures

Science.gov (United States)

Cullen, D. Kacy; Vukasinovic, Jelena; Glezer, Ari; La Placa, Michelle C.

2007-06-01

Three-dimensional (3D) neural cultures with cells distributed throughout a thick, bioactive protein scaffold may better represent neurobiological phenomena than planar correlates lacking matrix support. Neural cells in vivo interact within a complex, multicellular environment with tightly coupled 3D cell-cell/cell-matrix interactions; however, thick 3D neural cultures at cell densities approaching that of brain rapidly decay, presumably due to diffusion limited interstitial mass transport. To address this issue, we have developed a novel perfusion platform that utilizes forced intercellular convection to enhance mass transport. First, we demonstrated that in thick (>500 µm) 3D neural cultures supported by passive diffusion, cell densities =104 cells mm-3), continuous medium perfusion at 2.0-11.0 µL min-1 improved viability compared to non-perfused cultures (p death and matrix degradation. In perfused cultures, survival was dependent on proximity to the perfusion source at 2.00-6.25 µL min-1 (p 90% viability in both neuronal cultures and neuronal-astrocytic co-cultures. This work demonstrates the utility of forced interstitial convection in improving the survival of high cell density 3D engineered neural constructs and may aid in the development of novel tissue-engineered systems reconstituting 3D cell-cell/cell-matrix interactions.

The effect and fate of water-soluble carbon nanodots in maize (Zea mays L.).

Science.gov (United States)

Chen, Jing; Dou, Runzhi; Yang, Zhongzhou; Wang, Xiaoping; Mao, Chuanbin; Gao, Xiang; Wang, Li

2016-08-01

In this study, the toxicity of water-soluble carbon nanodots (C-dots) to maize (Zea mays L.) and their uptake and transport in plants were investigated. After exposed in sand matrix amended with 0-2000 mg/L C-dots for 4 weeks, we found that the phytotoxicity of C-dots was concentration-dependent. C-dots at 250 and 500 mg/L showed no toxicity to maize. However, 1000 and 2000 mg/L C-dots significantly reduced the fresh weight of root by 57% and 68%, and decreased the shoot fresh weight by 38% and 72%, respectively. Moreover, in maize roots, the exposure of C-dots at 2000 mg/L significantly increased the H2O2 content and lipid peroxidation (6.5 and 1.65 times higher, respectively), as well as, the antioxidant enzymes activities, up to 2, 1.5, 1.9 and 1.9 times higher for catalase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase, respectively. On the other hand, C-dots were observed in detached root-cap cells, cortex and vascular bundle of roots and mesophyll cells of leaves through fluorescence microscopy analysis, suggesting that C-dots were absorbed and translocated systemically in maize. Remarkably, a certain amount of C-dots were excreted out from leaf blade. To our knowledge, this is the first study combined phenotypic observation with physiologic responses and bioaccumulation and translocation analysis of C-dots to investigate their effect and fate in maize.

Bacterial endophytes from wild maize suppress Fusarium graminearum in modern maize and inhibit mycotoxin accumulation

Directory of Open Access Journals (Sweden)

Walaa Kamel Mousa

2015-10-01

Full Text Available Wild maize (teosinte has been reported to be less susceptible to pests than their modern maize (corn relatives. Endophytes, defined as microbes that inhabit plants without causing disease, are known for their ability to antagonize plant pests and pathogens. We hypothesized that the wild relatives of modern maize may host endophytes that combat pathogens. Fusarium graminearum is the fungus that causes Gibberella Ear Rot (GER in modern maize and produces the mycotoxin, deoxynivalenol (DON. In this study, 215 bacterial endophytes, previously isolated from diverse maize genotypes including wild teosintes, traditional landraces and modern varieties, were tested for their ability to antagonize F. graminearum in vitro. Candidate endophytes were then tested for their ability to suppress GER in modern maize in independent greenhouse trials. The results revealed that three candidate endophytes derived from wild teosintes were most potent in suppressing F. graminearum in vitro and GER in a modern maize hybrid. These wild teosinte endophytes could suppress a broad spectrum of fungal pathogens of modern crops in vitro. The teosinte endophytes also suppressed DON mycotoxin during storage to below acceptable safety threshold levels. A fourth, less robust anti-fungal strain was isolated from a modern maize hybrid. Three of the anti-fungal endophytes were predicted to be Paenibacillus polymyxa, along with one strain of Citrobacter. Microscopy studies suggested a fungicidal mode of action by all four strains. Molecular and biochemical studies showed that the P. polymyxa strains produced the previously characterized anti-Fusarium compound, fusaricidin. Our results suggest that the wild relatives of modern crops may serve as a valuable reservoir for endophytes in the ongoing fight against serious threats to modern agriculture. We discuss the possible impact of crop evolution and domestication on endophytes in the context of plant defense.

Cell sources for in vitro human liver cell culture models

Science.gov (United States)

Freyer, Nora; Damm, Georg; Seehofer, Daniel; Knöspel, Fanny

2016-01-01

In vitro liver cell culture models are gaining increasing importance in pharmacological and toxicological research. The source of cells used is critical for the relevance and the predictive value of such models. Primary human hepatocytes (PHH) are currently considered to be the gold standard for hepatic in vitro culture models, since they directly reflect the specific metabolism and functionality of the human liver; however, the scarcity and difficult logistics of PHH have driven researchers to explore alternative cell sources, including liver cell lines and pluripotent stem cells. Liver cell lines generated from hepatomas or by genetic manipulation are widely used due to their good availability, but they are generally altered in certain metabolic functions. For the past few years, adult and pluripotent stem cells have been attracting increasing attention, due their ability to proliferate and to differentiate into hepatocyte-like cells in vitro. However, controlling the differentiation of these cells is still a challenge. This review gives an overview of the major human cell sources under investigation for in vitro liver cell culture models, including primary human liver cells, liver cell lines, and stem cells. The promises and challenges of different cell types are discussed with a focus on the complex 2D and 3D culture approaches under investigation for improving liver cell functionality in vitro. Finally, the specific application options of individual cell sources in pharmacological research or disease modeling are described. PMID:27385595

Growth of melanocytes in human epidermal cell cultures

International Nuclear Information System (INIS)

Staiano-Coico, L.; Hefton, J.M.; Amadeo, C.; Pagan-Charry, I.; Madden, M.R.; Cardon-Cardo, C.

1990-01-01

Epidermal cell cultures were grown in keratinocyte-conditioned medium for use as burn wound grafts; the melanocyte composition of the grafts was studied under a variety of conditions. Melanocytes were identified by immunohistochemistry based on a monoclonal antibody (MEL-5) that has previously been shown to react specifically with melanocytes. During the first 7 days of growth in primary culture, the total number of melanocytes in the epidermal cultures decreased to 10% of the number present in normal skin. Beginning on day 2 of culture, bipolar melanocytes were present at a mean cell density of 116 +/- 2/mm2; the keratinocyte to melanocyte ratio was preserved during further primary culture and through three subpassages. Moreover, exposure of cultures to mild UVB irradiation stimulated the melanocytes to proliferate, suggesting that the melanocytes growing in culture maintained their responsiveness to external stimuli. When the sheets of cultured cells were enzymatically detached from the plastic culture flasks before grafting, melanocytes remained in the basal layer of cells as part of the graft applied to the patient

Cell Culture as an Alternative in Education.

Science.gov (United States)

Nardone, Roland M.

1990-01-01

Programs that are intended to inform and provide "hands-on" experience for students and to facilitate the introduction of cell culture-based laboratory exercises into the high school and college laboratory are examined. The components of the CellServ Program and the Cell Culture Toxicology Training Programs are described. (KR)

The usefulness of three-dimensional cell culture in induction of cancer stem cells from esophageal squamous cell carcinoma cell lines

International Nuclear Information System (INIS)

Fujiwara, Daisuke; Kato, Kazunori; Nohara, Shigeo; Iwanuma, Yoshimi; Kajiyama, Yoshiaki

2013-01-01

Highlights: •Spheroids were created from esophageal carcinoma cells using NanoCulture® Plates. •The proportion of strongly ALDH-positive cells increased in 3-D culture. •Expression of cancer stem cell-related genes was enhanced in 3-D culture. •CA-9 expression was enhanced, suggesting hypoxia had been induced in 3-D culture. •Drug resistance was increased. 3-D culture is useful for inducing cancer stem cells. -- Abstract: In recent years, research on resistance to chemotherapy and radiotherapy in cancer treatment has come under the spotlight, and researchers have also begun investigating the relationship between resistance and cancer stem cells. Cancer stem cells are assumed to be present in esophageal cancer, but experimental methods for identification and culture of these cells have not yet been established. To solve this problem, we created spheroids using a NanoCulture® Plate (NCP) for 3-dimensional (3-D) cell culture, which was designed as a means for experimentally reproducing the 3-D structures found in the body. We investigated the potential for induction of cancer stem cells from esophageal cancer cells. Using flow cytometry we analyzed the expression of surface antigen markers CD44, CD133, CD338 (ABCG2), CD318 (CDCP1), and CD326 (EpCAM), which are known cancer stem cell markers. None of these surface antigen markers showed enhanced expression in 3-D cultured cells. We then analyzed aldehyde dehydrogenase (ALDH) enzymatic activity using the ALDEFLUOR reagent, which can identify immature cells such as stem cells and precursor cells. 3-D-cultured cells were strongly positive for ALDH enzyme activity. We also analyzed the expression of the stem cell-related genes Sox-2, Nanog, Oct3/4, and Lin28 using RT-PCR. Expression of Sox-2, Nanog, and Lin28 was enhanced. Analysis of expression of the hypoxic surface antigen marker carbonic anhydrase-9 (CA-9), which is an indicator of cancer stem cell induction and maintenance, revealed that CA-9 expression

Distribution of azotobacter in rhizosphere of maize

International Nuclear Information System (INIS)

Tahir, M.B.; Baig, M.B.

1998-01-01

Azotobacter distribution and species composition were studied under maize rhizosphere at four growth stages and in the uncropped soil (control). The study was conducted in the glazed pots with 10 kg soil in each pot. Soil in the pots was enriched with 20 mg N/kg and 15 mg/P/kg in the form of urea and single super phosphate, respectively. Six plants of maize variety Akbar were grown in 32 pots. Four pots were used as control (check). Sampling was done at four growth stages of 20, 40, 60 and 80 days after the germination of the crop. Results indicated that Azotobacter population increased as the plant growth progressed, reached maximum (1320) cells g/sup -1/ of soil at flowering stage and then declined. A chroococcum was found to be the dominant species in the main rhizosphere. (author)

PECULIARITIES OF SECONDARY METABOLITES BIOSYNTHESIS IN PLANT CELL CULTURES

Directory of Open Access Journals (Sweden)

A.M. NOSOV

2014-06-01

Full Text Available metabolites formation in plant cell cultures of Panax spp., (ginsenosides; Dioscorea deltoidea (steroid glycosides; Ajuga reptans, Serratula coronata, Rhaponticum carthamoides (ecdisteroids; Polyscias spp., (triterpene glycosides, Taxus spp. (taxoids, Stevia rebaudiana (diterpene steviol-glycosides, Stephania glabra (alkaloids. They are some regular trends of secondary metabolites synthesis in the plant cell culture:It can be noted the stable synthesis of the compound promoting cell proliferation. Indeed, cell cultures of Dioscorea deltoidea were demonstrated to accumulate only furostanol glycosides, which promoted cell division. Furostanol glycoside content of Dioscorea strain DM-0.5 was up to 6 - 12% by dry biomass.Panax ginseng and P. japonicus plant cell cultures synthesize as minimum seven triterpene glycosides (ginsenosides, the productivity of these compounds was up to 6.0 - 8.0% on dry biomass.By contrast, the detectable synthesis of diterpene steviol-glycosides in cultivated cells of Stevia rebaudiana initiated in the mixotrophic cultures during chloroplast formation only.Despite these differences, or mainly due to them, plant cell cultures have become an attractive source of phytochemicals in alternative to collecting wild plants. It provides a guideline to bioreactor-based production of isoprenoids using undifferentiated plant cell cultures. 

Substrate utilisation by plant-cell cultures

Energy Technology Data Exchange (ETDEWEB)

Fowler, M W

1982-01-01

Plant cell cultures have been grown on a wide range of carbon sources in addition to the traditional ones of sucrose and glucose. Biomass yields and growth rates vary greatly between the different carbon sources and there is a variation in response between different cell cultures to individual carbon sources. Some attempts have been made to grow cell cultures on 'waste' and related carbon sources, such as lactose, maltose, starch, molasses and milk whey. Only maltose was found to support growth to anything near the levels observed with glucose and sucrose. In the case of molasses carbon source cell growth was either non-existent or only just measurable. All the data point to glucose as being the most suitable carbon source, principally on the grounds of biomass yield and growth rate. It should be noted, however, that other carbon sources do appear to have a major (positive) influence on natural product synthesis. Uptake into the cell is an important aspect of carbohydrate utilisation. There is strong evidence that from disaccharides upwards, major degradation to smaller units occurs before uptake. In some cases the necessary enzymes appear to be excreted into the culture broth, in others they may be located within the cell wall; invertase that hydrolyses sucrose is a good example. Once the products of carbohydrate degradation and mobilisation enter the cell they may suffer one of two fates, oxidation or utilisation for biosynthesis. The precise split between these two varies depending on such factors as cell growth rate, cell size, nutrient broth composition and carbohydrate status of the cells. In general rapidly growing cells have a high rate of oxidation, whereas cells growing more slowly tend to be more directed towards biosynthesis. Carbohydrate utilisation is a key area of study, underpinning as it does both biomass yield and natural product synthesis. (Refs. 13).

Modification of antioxidant systems in cell walls of maize roots by different nitrogen sources

International Nuclear Information System (INIS)

Hadži-Tašković Šukalović V; Vuletić, M.; Marković, K.; Željko, Vučinić; Kravić, N.

2016-01-01

Antioxidant systems of maize root cell walls grown on different nitrogen sources were evaluated. Plants were grown on a medium containing only NO3- or the mixture of NO3-+NH4+, in a 2:1 ratio. Eleven-day old plants, two days after the initiation of lateral roots, were used for the experiments. Cell walls were isolated from lateral roots and primary root segments, 2-7 cm from tip to base, representing zones of intense or decreased growth rates, respectively. Protein content and the activity of enzymes peroxidase, malate dehydrogenase and ascorbate oxidase ionically or covalently bound to the walls, as well as cell wall phenolic content and antioxidant capacity, were determined. Cell walls of plants grown on mixed N possess more developed enzymatic antioxidant systems and lower non-enzymatic antioxidant defenses than cell walls grown on NO3-. Irrespective of N treatment, the activities of all studied enzymes and protein content were higher in cell walls of lateral compared to primary roots. Phenolic content of cell walls isolated from lateral roots was higher in NO3--grown than in mixed N grown plants. No significant differences could be observed in the isozyme patterns of cell wall peroxidases isolated from plants grown on different nutrient solution. Our results indicate that different N treatments modify the antioxidant systems of root cell walls. Treatment with NO3- resulted in an increase of constitutive phenolic content, while the combination of NO3-+NH4+ elevated the redox enzyme activities in root cell walls.

Modification of antioxidant systems in cell walls of maize roots by different nitrogen sources

Energy Technology Data Exchange (ETDEWEB)

Hadži-Tašković Šukalović V; Vuletić, M.; Marković, K.; Željko, Vučinić; Kravić, N.

2016-07-01

Antioxidant systems of maize root cell walls grown on different nitrogen sources were evaluated. Plants were grown on a medium containing only NO3- or the mixture of NO3-+NH4+, in a 2:1 ratio. Eleven-day old plants, two days after the initiation of lateral roots, were used for the experiments. Cell walls were isolated from lateral roots and primary root segments, 2-7 cm from tip to base, representing zones of intense or decreased growth rates, respectively. Protein content and the activity of enzymes peroxidase, malate dehydrogenase and ascorbate oxidase ionically or covalently bound to the walls, as well as cell wall phenolic content and antioxidant capacity, were determined. Cell walls of plants grown on mixed N possess more developed enzymatic antioxidant systems and lower non-enzymatic antioxidant defenses than cell walls grown on NO3-. Irrespective of N treatment, the activities of all studied enzymes and protein content were higher in cell walls of lateral compared to primary roots. Phenolic content of cell walls isolated from lateral roots was higher in NO3--grown than in mixed N grown plants. No significant differences could be observed in the isozyme patterns of cell wall peroxidases isolated from plants grown on different nutrient solution. Our results indicate that different N treatments modify the antioxidant systems of root cell walls. Treatment with NO3- resulted in an increase of constitutive phenolic content, while the combination of NO3-+NH4+ elevated the redox enzyme activities in root cell walls.

Genetic fallout in biocultural landscapes: molecular imperialism and the cultural politics of (not) seeing transgenes in Mexico.

Science.gov (United States)

Christophe Bonneuil; Foyer, Jean; Wynne, Brian

2014-12-01

This article explores the trajectory of the global controversy over the introgression (or not) of transgenes from genetically modified maize into Mexican indigenous maize landraces. While a plurality of knowledge-making processes were deployed to render transgenes visible or invisible, we analyze how a particular in vitro based DNA-centered knowledge came to marginalize other forms of knowledge, thus obscuring other bio-cultural dimensions key to the understanding of gene flow and maize diversity. We show that dominant molecular norms of proof and standards of detection, which co-developed with the world of industrial monocropping and gene patenting, discarded and externalized non-compliant actors (i.e. complex maize genomes, human dimensions of gene flow). Operating in the name of high science, they hence obscured the complex biological and cultural processes that maintain crop diversity and enacted a cultural-political domination over the world of Mexican landraces and indigenous communities.

Biona-C Cell Culture pH Monitoring System

Science.gov (United States)

Friedericks, C.

1999-01-01

Sensors 2000! is developing a system to demonstrate the ability to perform accurate, real-time measurements of pH and CO2 in a cell culture media in Space. The BIONA-C Cell Culture pH Monitoring System consists of S2K! developed ion selective sensors and control electronics integrated with the fluidics of a cell culture system. The integrated system comprises a "rail" in the Cell Culture Module (CCM) of WRAIR (Space Biosciences of Walter Read Army Institute of Research). The CCM is a Space Shuttle mid-deck locker experiment payload. The BIONA-C is displayed along with associated graphics and text explanations. The presentation will stimulate interest in development of sensor technology for real-time cell culture measurements. The transfer of this technology to other applications will also be of interest. Additional information is contained in the original document.

"Achieving Mexico’s Maize Potential"

OpenAIRE

Antonio Turrent Fernández; Timothy A. Wise; Elise Garvey

2012-01-01

Rising agricultural prices, combined with growing import dependence, have driven Mexico’s food import bill over $20 billion per year and increased its agricultural trade deficit. Mexico imports one-third of its maize, overwhelmingly from the United States, but three million producers grow most of the country’s white maize, which is used primarily for tortillas and many other pluricultural products for human consumption. Yield gaps are large among the country’s small to medium-scale maize farm...

Rotary orbital suspension culture of embryonic stem cell-derived neural stem/progenitor cells: impact of hydrodynamic culture on aggregate yield, morphology and cell phenotype.

Science.gov (United States)

Laundos, Tiago L; Silva, Joana; Assunção, Marisa; Quelhas, Pedro; Monteiro, Cátia; Oliveira, Carla; Oliveira, Maria J; Pêgo, Ana P; Amaral, Isabel F

2017-08-01

Embryonic stem (ES)-derived neural stem/progenitor cells (ES-NSPCs) constitute a promising cell source for application in cell therapies for the treatment of central nervous system disorders. In this study, a rotary orbital hydrodynamic culture system was applied to single-cell suspensions of ES-NSPCs, to obtain homogeneously-sized ES-NSPC cellular aggregates (neurospheres). Hydrodynamic culture allowed the formation of ES-NSPC neurospheres with a narrower size distribution than statically cultured neurospheres, increasing orbital speeds leading to smaller-sized neurospheres and higher neurosphere yield. Neurospheres formed under hydrodynamic conditions (72 h at 55 rpm) showed higher cell compaction and comparable percentages of viable, dead, apoptotic and proliferative cells. Further characterization of cellular aggregates provided new insights into the effect of hydrodynamic shear on ES-NSPC behaviour. Rotary neurospheres exhibited reduced protein levels of N-cadherin and β-catenin, and higher deposition of laminin (without impacting fibronectin deposition), matrix metalloproteinase-2 (MMP-2) activity and percentage of neuronal cells. In line with the increased MMP-2 activity levels found, hydrodynamically-cultured neurospheres showed higher outward migration on laminin. Moreover, when cultured in a 3D fibrin hydrogel, rotary neurospheres generated an increased percentage of neuronal cells. In conclusion, the application of a constant orbital speed to single-cell suspensions of ES-NSPCs, besides allowing the formation of homogeneously-sized neurospheres, promoted ES-NSPC differentiation and outward migration, possibly by influencing the expression of cell-cell adhesion molecules and the secretion of proteases/extracellular matrix proteins. These findings are important when establishing the culture conditions needed to obtain uniformly-sized ES-NSPC aggregates, either for use in regenerative therapies or in in vitro platforms for biomaterial development or

Protein biosynthesis in cultured human hair follicle cells.

Science.gov (United States)

Weterings, P J; Vermorken, A J; Bloemendal, H

1980-10-31

A new technique has been used for culturing human keratinocytes. The cells grow on the basement membrane-like capsules of bovine lenses. Lens cells were removed from the capsules by rigid trypsinization. In order to exclude any contamination with remaining living cells the isolated capsules were irradiated with X-rays at a dose of 10,000 rad. In this way human epithelial cells can be brought in culture from individual hair follicles. Since feeder cells are not used in this culture technique, the biosynthesis of keratinocyte proteins can be studied in these cultures. The newly synthesized proteins can be separated into a water-soluble, a urea-soluble, and a urea-insoluble fraction. Product analysis has been performed on the first two fractions revealing protein patterns identical to those of intact hair follicles. Product analysis of the urea-soluble fractions of microdissected hair follicles shows that the protein pattern of the cultured keratinocytes resembles the protein pattern of the hair follicle sheath. Studies on the metabolism of benzo(a)pyrene revealed that the enzyme aryl hydrocarbon hydroxylase (AHH) is present in cultured hair follicle cells. A possible use of our culture system for eventual detection of inherited predisposition for smoking-dependent lung cancer is discussed.

Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.

Science.gov (United States)

Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka

2014-05-01

Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses. Copyright © 2014. Published by Elsevier GmbH.

Nitrogen-15 uptake by whole plants and root callus cultures of inbred maize lines and their F1 hybrids

International Nuclear Information System (INIS)

Mladenova, Y.; Karadimova, M.

1981-01-01

The uptake of nitrogen-15 by 3 maize genotypes was investigated. Comparative analysis of N15 assimilation and distribution in the organs of intact plants of two self-pollinated lines and their F1 hybrid and also in a callus tissue of roots of the same genotypes was made. From the results the conclusion is drawn that the N-use efficiency of the female line is higher than that of the male line both in intact plants and callus tissues from roots. This fact indicates that the N-use efficiency is determined not only by the functions of the cells in the shoots, suggesting the participation of the photosynthetic carboxylases but also by the functions of cells without a photosynthesizing apparatus. The N-use efficiency in the F1 hybrid manifests ''heterosis'', in spite of the intact plants or root callus tissues are being studied. (author)

Exploring maize-legume intercropping systems in Southwest Mexico

NARCIS (Netherlands)

Flores-Sanchez, D.; Pastor, A.V.; Lantinga, E.A.; Rossing, W.A.H.; Kropff, M.J.

2013-01-01

Maize yields in continuous maize production systems of smallholders in the Costa Chica, a region in Southwest Mexico, are low despite consistent inputs of fertilizers and herbicides. This study was aimed at investigating the prospects of intercropping maize (Zea mays L.) and maize-roselle (Hibiscus

Enhanced water stress tolerance of transgenic maize plants over-expressing LEA Rab28 gene.

Science.gov (United States)

Amara, Imen; Capellades, Montserrat; Ludevid, M Dolors; Pagès, Montserrat; Goday, Adela

2013-06-15

Late Embryogenesis Abundant (LEA) proteins participate in plant stress responses and contribute to the acquisition of desiccation tolerance. In this report Rab28 LEA gene has been over-expressed in maize plants under a constitutive maize promoter. The expression of Rab28 transcripts led to the accumulation and stability of Rab28 protein in the transgenic plants. Native Rab28 protein is localized to nucleoli in wild type maize embryo cells; here we find by whole-mount immunocytochemistry that in root cells of Rab28 transgenic and wild-type plants the protein is also associated to nucleolar structures. Transgenic plants were tested for stress tolerance and resulted in sustained growth under polyethyleneglycol (PEG)-mediated dehydration compared to wild-type controls. Under osmotic stress transgenic seedlings showed increased leaf and root areas, higher relative water content (RWC), reduced chlorophyll loss and lower Malondialdehyde (MDA) production in relation to wild-type plants. Moreover, transgenic seeds exhibited higher germination rates than wild-type seeds under water deficit. Overall, our results highlight the presence of transgenic Rab28 protein in nucleolar structures and point to the potential of group 5 LEA Rab28 gene as candidate to enhance stress tolerance in maize plants. Copyright © 2013 Elsevier GmbH. All rights reserved.

Climatic and non-climatic drivers of spatiotemporal maize-area dynamics across the northern limit for maize production

DEFF Research Database (Denmark)

Odgaard, Mette Vestergaard; Bøcher, Peder Klith; Dalgaard, Tommy

2011-01-01

It is expected that the ongoing anthropogenic climate change will drive changes in agricultural production and its geographic distribution. Here, we assess the extent to which climate change is already driving spatiotemporal dynamics in maize production in Denmark. We use advanced spatial...... regression modeling with multi-model averaging to assess the extent to which the recent spatiotemporal dynamics of the maize area in Denmark are driven by climate (temperature as represented by maize heating units [MHU] and growing-season precipitation), climate change and non-climatic factors (cattle...... cultivation and cattle farming, probably reflecting a change to a more favorable climate for maize cultivation: in the beginning of the study period, northern areas were mostly too cold for maize cultivation, irrespective of cattle density, but this limitation has been diminishing as climate has warmed...

21 CFR 864.2280 - Cultured animal and human cells.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cultured animal and human cells. 864.2280 Section... Cultured animal and human cells. (a) Identification. Cultured animal and human cells are in vitro cultivated cell lines from the tissue of humans or other animals which are used in various diagnostic...

Culture of human mesenchymal stem cells using a candidate pharmaceutical grade xeno-free cell culture supplement derived from industrial human plasma pools.

Science.gov (United States)

Díez, José M; Bauman, Ewa; Gajardo, Rodrigo; Jorquera, Juan I

2015-03-13

Fetal bovine serum (FBS) is an animal product used as a medium supplement. The animal origin of FBS is a concern if cultured stem cells are to be utilized for human cell therapy. Therefore, a substitute for FBS is desirable. In this study, an industrial, xeno-free, pharmaceutical-grade supplement for cell culture (SCC) under development at Grifols was tested for growth of human mesenchymal stem cells (hMSCs), cell characterization, and differentiation capacity. SCC is a freeze-dried product obtained through cold-ethanol fractionation of industrial human plasma pools from healthy donors. Bone marrow-derived hMSC cell lines were obtained from two commercial suppliers. Cell growth was evaluated by culturing hMSCs with commercial media or media supplemented with SCC or FBS. Cell viability and cell yield were assessed with an automated cell counter. Cell surface markers were studied by indirect immunofluorescence assay. Cells were cultured then differentiated into adipocytes, chondrocytes, osteoblasts, and neurons, as assessed by specific staining and microscopy observation. SCC supported the growth of commercial hMSCs. Starting from the same number of seeded cells in two consecutive passages of culture with medium supplemented with SCC, hMSC yield and cell population doubling time were equivalent to the values obtained with the commercial medium and was consistent among lots. The viability of hMSCs was higher than 90%, while maintaining the characteristic phenotype of undifferentiated hMSCs (positive for CD29, CD44, CD90, CD105, CD146, CD166 and Stro-1; negative for CD14 and CD19). Cultured hMSCs maintained the potential for differentiation into adipocytes, chondrocytes, osteoblasts, and neurons. The tested human plasma-derived SCC sustains the adequate growth of hMSCs, while preserving their differentiation capacity. SCC can be a potential candidate for cell culture supplement in advanced cell therapies.

Differential marker expression by cultures rich in mesenchymal stem cells

Science.gov (United States)

2013-01-01

Background Mesenchymal stem cells have properties that make them amenable to therapeutic use. However, the acceptance of mesenchymal stem cells in clinical practice requires standardized techniques for their specific isolation. To date, there are no conclusive marker (s) for the exclusive isolation of mesenchymal stem cells. Our aim was to identify markers differentially expressed between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. We compared and contrasted the phenotype of tissue cultures in which mesenchymal stem cells are rich and rare. By initially assessing mesenchymal stem cell differentiation, we established that bone marrow and breast adipose cultures are rich in mesenchymal stem cells while, in our hands, foreskin fibroblast and olfactory tissue cultures contain rare mesenchymal stem cells. In particular, olfactory tissue cells represent non-stem cell mesenchymal cells. Subsequently, the phenotype of the tissue cultures were thoroughly assessed using immuno-fluorescence, flow-cytometry, proteomics, antibody arrays and qPCR. Results Our analysis revealed that all tissue cultures, regardless of differentiation potential, demonstrated remarkably similar phenotypes. Importantly, it was also observed that common mesenchymal stem cell markers, and fibroblast-associated markers, do not discriminate between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. Examination and comparison of the phenotypes of mesenchymal stem cell and non-stem cell mesenchymal cell cultures revealed three differentially expressed markers – CD24, CD108 and CD40. Conclusion We indicate the importance of establishing differential marker expression between mesenchymal stem cells and non-stem cell mesenchymal cells in order to determine stem cell specific markers. PMID:24304471

Chromosomal instability and telomere shortening in long-term culture of hematopoietic stem cells: insights from a cell culture model of RPS14 haploinsufficiency.

Science.gov (United States)

Thomay, K; Schienke, A; Vajen, B; Modlich, U; Schambach, A; Hofmann, W; Schlegelberger, B; Göhring, G

2014-01-01

The fate of cultivated primary hematopoietic stem cells (HSCs) with respect to genetic instability and telomere attrition has not yet been described in great detail. Thus, knowledge of the genetic constitution of HSCs is important when interpreting results of HSCs in culture. While establishing a cell culture model for myelodysplastic syndrome with a deletion in 5q by performing RPS14 knockdown, we found surprising data that may be of importance for any CD34+ cell culture experiments. We performed cytogenetic analyses and telomere length measurement on transduced CD34+ cells and untransduced control cells to observe the effects of long-term culturing. Initially, CD34+ cells had a normal median telomere length of about 12 kb and showed no signs of chromosomal instability. During follow-up, the median telomere length seemed to decrease and, simultaneously, increased chromosomal instability could be observed - in modified and control cells. One culture showed a clonal monosomy 7 - independent of prior RPS14 knockdown. During further culturing, it seemed that the telomeres re-elongated, and chromosomes stabilized, while TERT expression was not elevated. In summary, irrespective of our results of RPS14 knockdown in the long-term culture of CD34+ cells, it becomes clear that cell culture artefacts inducing telomere shortening and chromosomal instability have to be taken into account and regular cytogenetic analyses should always be performed. © 2013 S. Karger AG, Basel.

Stem characteristics of two forage maize (Zea mays L.) cultivars varying in whole plant digestibility. I. Relevant morphological parameters

NARCIS (Netherlands)

Boon, E.J.M.C.; Engels, F.M.; Struik, P.C.; Cone, J.W.

2005-01-01

The morphology and rumen fermentation kinetics of the maize cultivars (Zea mays L.) Vitaro and Volens were investigated in detail throughout their growing period as a first step towards understanding the relation between plant characteristics and cell wall fermentability of forage maize. Vitaro is

A single-cell and feeder-free culture system for monkey embryonic stem cells.

Science.gov (United States)

Ono, Takashi; Suzuki, Yutaka; Kato, Yosuke; Fujita, Risako; Araki, Toshihiro; Yamashita, Tomoko; Kato, Hidemasa; Torii, Ryuzo; Sato, Naoya

2014-01-01

Primate pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), hold great potential for research and application in regenerative medicine and drug discovery. To maximize primate PSC potential, a practical system is required for generating desired functional cells and reproducible differentiation techniques. Much progress regarding their culture systems has been reported to date; however, better methods would still be required for their practical use, particularly in industrial and clinical fields. Here we report a new single-cell and feeder-free culture system for primate PSCs, the key feature of which is an originally formulated serum-free medium containing FGF and activin. In this culture system, cynomolgus monkey ESCs can be passaged many times by single-cell dissociation with traditional trypsin treatment and can be propagated with a high proliferation rate as a monolayer without any feeder cells; further, typical PSC properties and genomic stability can be retained. In addition, it has been demonstrated that monkey ESCs maintained in the culture system can be used for various experiments such as in vitro differentiation and gene manipulation. Thus, compared with the conventional culture system, monkey ESCs grown in the aforementioned culture system can serve as a cell source with the following practical advantages: simple, stable, and easy cell maintenance; gene manipulation; cryopreservation; and desired differentiation. We propose that this culture system can serve as a reliable platform to prepare primate PSCs useful for future research and application.

Stimulation of the proliferation of hemopoietic stem cells in irradiated bone marrow cell culture

International Nuclear Information System (INIS)

Mori, K.J.; Izumi, H.; Seto, A.

1981-01-01

Long-term hemopoiesis was established in bone marrow cell culture in vitro. This culture was shown to support the recovery proliferation of hemopoietic stem cells completely in vitro after irradiation. Hemopoietic stem cells were stimulated into proliferation in culture when normal bone marrow cells were overlayed on top of the irradiated adherent cell colonies. These results indicate that proliferation and differentiation of hemopoietic stem cells in vitro are also supported by stromahemopoietic cell interactions

Status of maize stalk rot complex in western belts of Nepal and its integrated management

Directory of Open Access Journals (Sweden)

Subash Subedi

2016-12-01

Full Text Available Maize stalk rot complex is becoming a serious threat for maize growing areas of Nepal. A field monitoring for maize stalk rot complex was done during crop season (August, 2016 covering 10 farmers field each of Surkhet, Banke, Dang, Chitwan and Nawalparasi districts. Maize crop showed highly susceptible reaction to the disease at western belts of Dang and susceptible reaction was marked in Chitwan and Nawalparasi districts while the disease effect was mild at Banke and Surkhet district. Most of the plant diseases managed successfully through the application of bio-control agents, host resistance, chemicals and other different cultural control methods. The result of field experiment conducted at Dang showed that all the treatments had significant (P≤0.05 effect on percent disease index (PDI and crop yield over farmers practice to control maize stalk rot. The higher percent disease control (52.36% and yield increase (40.29% were recorded from the plot sprayed with streptocyclin @ 2 g L-1 and insecticide (cypermethrin + chloropyrifos @ 2.5 ml L-1 of water during knee height and subsequent spray after 15 days interval as compared to farmers practice. Out of 30 genotypes, Rampur composit, Arun 2, Rampur 34, RamS03F08, TLBRS07F16 and Rampur 24 were found resistant against stalk rot complex with higher yield at Rampur Chitwan.

Nucleotide diversity of the ZmPox3 maize peroxidase gene: Relationships between a MITE insertion in exon 2 and variation in forage maize digestibility

Directory of Open Access Journals (Sweden)

Rigau Joan

2004-07-01

Full Text Available Abstract Background Polymorphisms were investigated within the ZmPox3 maize peroxidase gene, possibly involved in lignin biosynthesis because of its colocalization with a cluster of QTL related to lignin content and cell wall digestibility. The purpose of this study was to identify, on the basis of 37 maize lines chosen for their varying degrees of cell wall digestibility and representative of temperate regions germplasm, ZmPox3 haplotypes or individual polymorphisms possibly associated with digestibility. Results Numerous haplotypes with high diversity were identified. Frequency of nucleotide changes was high with on average one SNP every 57 bp. Nucleotide diversity was not equally distributed among site categories: the estimated π was on average eight times higher for silent sites than for non-synonymous sites. Numerous sites were in linkage disequilibrium that decayed with increasing physical distance. A zmPox3 mutant allele, carrying an insertion of a transposable element in the second exon, was found in lines derived from the early flint inbred line, F7. This element possesses many structural features of miniature inverted-repeat transposable elements (MITE. The mutant allele encodes a truncated protein lacking important functional sites. An ANOVA performed with a subset of 31 maize lines indicated that the transposable element was significantly associated with cell wall digestibility. This association was confirmed using an additional set of 25 flint lines related to F7. Moreover, RT-PCR experiments revealed a decreased amount of corresponding mRNA in plants with the MITE insertion. Conclusion These results showed that ZmPox3 could possibly be involved in monolignol polymerisation, and that a deficiency in ZmPox3 peroxidase activity seemingly has a negative effect on cell wall digestibility. Also, genetic diversity analyses of ZmPox3 indicated that this peroxidase could be a relevant target for grass digestibility improvement using

Cell Culture in Microgravity: Opening the Door to Space Cell Biology

Science.gov (United States)

Pellis, Neal R.; Dawson, David L. (Technical Monitor)

1999-01-01

Adaptational response of human cell populations to microgravity is investigated using simulation, short-term Shuttle experiments, and long-term microgravity. Simulation consists of a clinostatically-rotated cell culture system. The system is a horizontally-rotated cylinder completely filled with culture medium. Low speed rotation results in continuous-fall of the cells through the fluid medium. In this setting, cells: 1) aggregate, 2) propagate in three dimensions, 3) synthesize matrix, 4) differentiate, and 5) form sinusoids that facilitate mass transfer. Space cell culture is conducted in flight bioreactors and in static incubators. Cells grown in microgravity are: bovine cartilage, promyelocytic leukemia, kidney proximal tubule cells, adrenal medulla, breast and colon cancer, and endothelium. Cells were cultured in space to test specific hypotheses. Cartilage cells were used to determine structural differences in cartilage grown in space compared to ground-based bioreactors. Results from a 130-day experiment on Mir revealed that cartilage grown in space was substantially more compressible due to insufficient glycosaminoglycan in the matrix. Interestingly, earth-grown cartilage conformed better to the dimensions of the scaffolding material, while the Mir specimens were spherical. The other cell populations are currently being analyzed for cell surface properties, gene expression, and differentiation. Results suggest that some cells spontaneously differentiate in microgravity. Additionally, vast changes in gene expression may occur in response to microgravity. In conclusion, the transition to microgravity may constitute a physical perturbation in cells resulting in unique gene expressions, the consequences of which may be useful in tissue engineering, disease modeling, and space cell biology.

How do culture media influence in vitro perivascular cell behavior?

Science.gov (United States)

Huber, Birgit; Volz, Ann-Cathrin; Kluger, Petra Juliane

2015-12-01

Perivascular cells are multilineage cells located around the vessel wall and important for wall stabilization. In this study, we evaluated a stem cell media and a perivascular cell-specific media for the culture of primary perivascular cells regarding their cell morphology, doubling time, stem cell properties, and expression of cell type-specific markers. When the two cell culture media were compared to each other, perivascular cells cultured in the stem cell medium had a more elongated morphology and a faster doubling rate and cells cultured in the pericyte medium had a more typical morphology, with several filopodia, and a slower doubling rate. To evaluate stem cell properties, perivascular cells, CD146(-) cells, and mesenchymal stem cells (MSCs) were differentiated into the adipogenic, osteogenic, and chondrogenic lineages. It was seen that perivascular cells, as well as CD146(-) cells and MSCs, cultured in stem cell medium showed greater differentiation than cells cultured in pericyte-specific medium. The expression of pericyte-specific markers CD146, neural/glial antigen 2 (NG2), platelet-derived growth factor receptor-β (PDGFR-β), myosin, and α-smooth muscle actin (α-SMA) could be found in both pericyte cultures, as well as to varying amounts in CD146(-) cells, MSCs, and endothelial cells. The here presented work shows that perivascular cells can adapt to their in vitro environment and cell culture conditions influence cell functionality, such as doubling rate or differentiation behavior. Pericyte-specific markers were shown to be expressed also from cells other than perivascular cells. We can further conclude that CD146(+) perivascular cells are inhomogeneous cell population probably containing stem cell subpopulations, which are located perivascular around capillaries. © 2015 International Federation for Cell Biology.

Biogelx: Cell Culture on Self-Assembling Peptide Gels.

Science.gov (United States)

Harper, Mhairi M; Connolly, Michael L; Goldie, Laura; Irvine, Eleanore J; Shaw, Joshua E; Jayawarna, Vineetha; Richardson, Stephen M; Dalby, Matthew J; Lightbody, David; Ulijn, Rein V

2018-01-01

Aromatic peptide amphiphiles can form self-supporting nanostructured hydrogels with tunable mechanical properties and chemical compositions. These hydrogels are increasingly applied in two-dimensional (2D) and three-dimensional (3D) cell culture, where there is a rapidly growing need to store, grow, proliferate, and manipulate naturally derived cells within a hydrated, 3D matrix. Biogelx Limited is a biomaterials company, created to commercialize these bio-inspired hydrogels to cell biologists for a range of cell culture applications. This chapter describes methods of various characterization and cell culture techniques specifically optimized for compatibility with Biogelx products.

Influence of Kernel Age on Fumonisin B1 Production in Maize by Fusarium moniliforme

Science.gov (United States)

Warfield, Colleen Y.; Gilchrist, David G.

1999-01-01

Production of fumonisins by Fusarium moniliforme on naturally infected maize ears is an important food safety concern due to the toxic nature of this class of mycotoxins. Assessing the potential risk of fumonisin production in developing maize ears prior to harvest requires an understanding of the regulation of toxin biosynthesis during kernel maturation. We investigated the developmental-stage-dependent relationship between maize kernels and fumonisin B1 production by using kernels collected at the blister (R2), milk (R3), dough (R4), and dent (R5) stages following inoculation in culture at their respective field moisture contents with F. moniliforme. Highly significant differences (P ≤ 0.001) in fumonisin B1 production were found among kernels at the different developmental stages. The highest levels of fumonisin B1 were produced on the dent stage kernels, and the lowest levels were produced on the blister stage kernels. The differences in fumonisin B1 production among kernels at the different developmental stages remained significant (P ≤ 0.001) when the moisture contents of the kernels were adjusted to the same level prior to inoculation. We concluded that toxin production is affected by substrate composition as well as by moisture content. Our study also demonstrated that fumonisin B1 biosynthesis on maize kernels is influenced by factors which vary with the developmental age of the tissue. The risk of fumonisin contamination may begin early in maize ear development and increases as the kernels reach physiological maturity. PMID:10388675

Importance of NDF digestibility of whole crop maize silage for dry matter intake and milk production in dairy cows

DEFF Research Database (Denmark)

Krämer, Monika; Lund, Peter; Weisbjerg, Martin Riis

2016-01-01

The importance of maize silage as a feed component in cattle rations and for biogas production has substantially increased. Whole crop maize silage is a forage with a high starch concentration, but also the cell wall fraction, commonly analysed as neutral detergent fibre (aNDFom) is a major energ...... silage aNDFom digestibility improved daily milk yield with 82 g (P = 0.04) and daily weight gain with 12 g (P = 0.03). Therefore, aNDFom digestibility is an important trait in maize used as whole crop silage for dairy cows.......The importance of maize silage as a feed component in cattle rations and for biogas production has substantially increased. Whole crop maize silage is a forage with a high starch concentration, but also the cell wall fraction, commonly analysed as neutral detergent fibre (aNDFom) is a major energy...... source for use in ruminant nutrition. Even though ruminants require forage fibre to maintain rumen function and maximize productivity, excess fibre limits feed intake due to its contribution to physical fill in the rumen. As feed intake is the most important factor for milk production, both a...

Transformation of elite white maize using the particle inflow gun and detailed analysis of a low-copy integration event

CSIR Research Space (South Africa)

O'Kennedy, MM

2001-12-01

Full Text Available of these transformation events was demonstrat- ed by Southern blot analysis and by transgene expres- sion. In this event, the transgenes bar and uidA were in- serted in tandem. Keywords Elite white maize transformation ? Cereals ? Immature embryos ? Biolistics ? Fertile... study, only embryogenic white, compact structured calli, desig- nated type-I calli, were produced when immature zygotic embryos of the selected elite maize lines were cultured. The type-I calli regenerated to produce fertile plants. Although 40...

Effect of Thorium on Growth and Uptake of Some Elements by Maize Plant

International Nuclear Information System (INIS)

Al-Shobaki, M.E.E.

2012-01-01

A pot experiment (sand culture) was carried out to investigate the effect of thorium on maize dry matter yield, contents and uptake of N,P ,K, Na and Fe and thorium accumulation in maize plant.The pots were contaminated by thorium as Thorium Nitrate(Th (NO 3 ) 4 ,H 2 O)at concentrations 0,5,10,11,12,13,14,15 and 50 ppm. Pots irrigated by 1/10 Hogland solution for 15 days, increased tol/4 Hogland solution after that.The results show that the dry matter (shoot, root and whole plant)decreased with increasing thorium concentration in soil up to 12 ppm and slightly increased with increasing Th to 13 ppm . The Nitrogen content and its uptake decreased with increasing thorium concentration in media growth up to 11 ppm .They were slightly increased at Th concentration between 11-14 ppm in maize shoot and root. The shoots always contained N-content and uptake more than that found in roots . P- uptake decreased in both shoots and roots with increasing in thorium concentration in media growth.

Computing the biomass potentials for maize and two alternative energy crops, triticale and cup plant (Silphium perfoliatum L.), with the crop model BioSTAR in the region of Hannover (Germany).

Science.gov (United States)

Bauböck, Roland; Karpenstein-Machan, Marianne; Kappas, Martin

2014-01-01

Lower Saxony (Germany) has the highest installed electric capacity from biogas in Germany. Most of this electricity is generated with maize. Reasons for this are the high yields and the economic incentive. In parts of Lower Saxony, an expansion of maize cultivation has led to ecological problems and a negative image of bioenergy as such. Winter triticale and cup plant have both shown their suitability as alternative energy crops for biogas production and could help to reduce maize cultivation. The model Biomass Simulation Tool for Agricultural Resources (BioSTAR) has been validated with observed yield data from the region of Hannover for the cultures maize and winter wheat. Predicted yields for the cultures show satisfactory error values of 9.36% (maize) and 11.5% (winter wheat). Correlations with observed data are significant ( P  alternative to maize in the region of Hanover and other places in Lower Saxony. The model BioSTAR simulated yields for maize and winter wheat in the region of Hannover at a good overall level of accuracy (combined error 10.4%). Due to input data aggregation, individual years show high errors though (up to 30%). Nevertheless, the BioSTAR crop model has proven to be a functioning tool for the prediction of agricultural biomass potentials under varying environmental and crop management frame conditions.

Development of a microfluidic perfusion 3D cell culture system

Science.gov (United States)

Park, D. H.; Jeon, H. J.; Kim, M. J.; Nguyen, X. D.; Morten, K.; Go, J. S.

2018-04-01

Recently, 3-dimensional in vitro cell cultures have gained much attention in biomedical sciences because of the closer relevance between in vitro cell cultures and in vivo environments. This paper presents a microfluidic perfusion 3D cell culture system with consistent control of long-term culture conditions to mimic an in vivo microenvironment. It consists of two sudden expansion reservoirs to trap incoming air bubbles, gradient generators to provide a linear concentration, and microchannel mixers. Specifically, the air bubbles disturb a flow in the microfluidic channel resulting in the instability of the perfusion cell culture conditions. For long-term stable operation, the sudden expansion reservoir is designed to trap air bubbles by using buoyancy before they enter the culture system. The performance of the developed microfluidic perfusion 3D cell culture system was examined experimentally and compared with analytical results. Finally, it was applied to test the cytotoxicity of cells infected with Ewing’s sarcoma. Cell death was observed for different concentrations of H2O2. For future work, the developed microfluidic perfusion 3D cell culture system can be used to examine the behavior of cells treated with various drugs and concentrations for high-throughput drug screening.

Cardiac Cells Beating in Culture: A Laboratory Exercise

Science.gov (United States)

Weaver, Debora

2007-01-01

This article describes how to establish a primary tissue culture, where cells are taken directly from an organ of a living animal. Cardiac cells are taken from chick embryos and transferred to culture dishes. These cells are not transformed and therefore have a limited life span. However, the unique characteristics of cardiac cells are maintained…

Pollen-Mediated Gene Flow in Maize: Implications for Isolation Requirements and Coexistence in Mexico, the Center of Origin of Maize.

Science.gov (United States)

Baltazar, Baltazar M; Castro Espinoza, Luciano; Espinoza Banda, Armando; de la Fuente Martínez, Juan Manuel; Garzón Tiznado, José Antonio; González García, Juvencio; Gutiérrez, Marco Antonio; Guzmán Rodríguez, José Luis; Heredia Díaz, Oscar; Horak, Michael J; Madueño Martínez, Jesús Ignacio; Schapaugh, Adam W; Stojšin, Duška; Uribe Montes, Hugo Raúl; Zavala García, Francisco

2015-01-01

Mexico, the center of origin of maize (Zea mays L.), has taken actions to preserve the identity and diversity of maize landraces and wild relatives. Historically, spatial isolation has been used in seed production to maintain seed purity. Spatial isolation can also be a key component for a strategy to minimize pollen-mediated gene flow in Mexico between transgenic maize and sexually compatible plants of maize conventional hybrids, landraces, and wild relatives. The objective of this research was to generate field maize-to-maize outcrossing data to help guide coexistence discussions in Mexico. In this study, outcrossing rates were determined and modeled from eight locations in six northern states, which represent the most economically important areas for the cultivation of hybrid maize in Mexico. At each site, pollen source plots were planted with a yellow-kernel maize hybrid and surrounded by plots with a white-kernel conventional maize hybrid (pollen recipient) of the same maturity. Outcrossing rates were then quantified by assessing the number of yellow kernels harvested from white-kernel hybrid plots. The highest outcrossing values were observed near the pollen source (12.9% at 1 m distance). The outcrossing levels declined sharply to 4.6, 2.7, 1.4, 1.0, 0.9, 0.5, and 0.5% as the distance from the pollen source increased to 2, 4, 8, 12, 16, 20, and 25 m, respectively. At distances beyond 20 m outcrossing values at all locations were below 1%. These trends are consistent with studies conducted in other world regions. The results suggest that coexistence measures that have been implemented in other geographies, such as spatial isolation, would be successful in Mexico to minimize transgenic maize pollen flow to conventional maize hybrids, landraces and wild relatives.

Improved endothelial cell seeding with cultured cells and fibronectin-coated grafts

International Nuclear Information System (INIS)

Seeger, J.M.; Klingman, N.

1985-01-01

A possible approach to the low seeding efficiency of endothelial cells into prosthetic grafts is to increase the number of cells to be seeded in cell culture and improve seeding efficiency by graft precoating with fibronectin. The effect of cell culture on cell adhesion is unknown, however, and fibronectin also binds fibrin, which may increase the thrombogenicity of the graft luminal surface. To investigate these questions, freshly harvested canine jugular vein endothelial cells from six animals and similar cells harvested from six primary and eight secondary cell cultures were labeled with 111 Indium and seeded into 5 cm, 4 mm PTFE grafts coated with fibronectin, using similar uncoated PTFE grafts as controls. Platelet accumulation and distribution on six similar coated and uncoated grafts placed in canine carotid, external jugular arterial venous shunts for 2 hr were also determined using autogenous 111 Indium-labeled platelets. Significant differences between group means were determined using the paired Student's t test. Results reveal that seeding efficiency is significantly better in all groups of coated grafts compared to uncoated grafts (P less than 0.01). Cells derived from cell culture also had significantly higher seeding efficiencies than freshly harvested cells when seeded into coated grafts (P less than 0.05) and tended to have higher seeding efficiencies than harvested cells when seeded into uncoated grafts (P = 0.53). Fibronectin coating increased mean platelet accumulation on the entire graft luminal surface, but not to a statistically significant degree (P greater than 0.1). Whether this increased seeding efficiency will improve graft endothelialization remains to be investigated

Dynamic cell culture system: a new cell cultivation instrument for biological experiments in space

Science.gov (United States)

Gmunder, F. K.; Nordau, C. G.; Tschopp, A.; Huber, B.; Cogoli, A.

1988-01-01

The prototype of a miniaturized cell cultivation instrument for animal cell culture experiments aboard Spacelab is presented (Dynamic cell culture system: DCCS). The cell chamber is completely filled and has a working volume of 200 microliters. Medium exchange is achieved with a self-powered osmotic pump (flowrate 1 microliter h-1). The reservoir volume of culture medium is 230 microliters. The system is neither mechanically stirred nor equipped with sensors. Hamster kidney (Hak) cells growing on Cytodex 3 microcarriers were used to test the biological performance of the DCCS. Growth characteristics in the DCCS, as judged by maximal cell density, glucose consumption, lactic acid secretion and pH, were similar to those in cell culture tubes.

Quantitative volumetric Raman imaging of three dimensional cell cultures

KAUST Repository

Kallepitis, Charalambos; Bergholt, Mads S.; Mazo, Manuel M.; Leonardo, Vincent; Skaalure, Stacey C.; Maynard, Stephanie A.; Stevens, Molly M.

2017-01-01

in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies

Benzoxazinoids in root exudates of maize attract Pseudomonas putida to the rhizosphere.

Directory of Open Access Journals (Sweden)

Andrew L Neal

Full Text Available Benzoxazinoids, such as 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H-one (DIMBOA, are secondary metabolites in grasses. In addition to their function in plant defence against pests and diseases above-ground, benzoxazinoids (BXs have also been implicated in defence below-ground, where they can exert allelochemical or antimicrobial activities. We have studied the impact of BXs on the interaction between maize and Pseudomonas putida KT2440, a competitive coloniser of the maize rhizosphere with plant-beneficial traits. Chromatographic analyses revealed that DIMBOA is the main BX compound in root exudates of maize. In vitro analysis of DIMBOA stability indicated that KT2440 tolerance of DIMBOA is based on metabolism-dependent breakdown of this BX compound. Transcriptome analysis of DIMBOA-exposed P. putida identified increased transcription of genes controlling benzoate catabolism and chemotaxis. Chemotaxis assays confirmed motility of P. putida towards DIMBOA. Moreover, colonisation essays in soil with Green Fluorescent Protein (GFP-expressing P. putida showed that DIMBOA-producing roots of wild-type maize attract significantly higher numbers of P. putida cells than roots of the DIMBOA-deficient bx1 mutant. Our results demonstrate a central role for DIMBOA as a below-ground semiochemical for recruitment of plant-beneficial rhizobacteria during the relatively young and vulnerable growth stages of maize.

System-level modeling and simulation of the cell culture microfluidic biochip ProCell

DEFF Research Database (Denmark)

Minhass, Wajid Hassan; Pop, Paul; Madsen, Jan

2010-01-01

Microfluidic biochips offer a promising alternative to a conventional biochemical laboratory. There are two technologies for the microfluidic biochips: droplet-based and flow-based. In this paper we are interested in flow-based microfluidic biochips, where the liquid flows continuously through pre......-defined micro-channels using valves and pumps. We present an approach to the system-level modeling and simulation of a cell culture microfluidic biochip called ProCell, Programmable Cell Culture Chip. ProCell contains a cell culture chamber, which is envisioned to run 256 simultaneous experiments (viewed...

Culturing of PC12 Cells, Neuronal Cells, Astrocytes Cultures and Brain Slices in an Open Microfluidic System

DEFF Research Database (Denmark)

Al Atraktchi, Fatima Al-Zahraa; Bakmand, Tanya; Rømer Sørensen, Ane

The brain is the center of the nervous system, where serious neurodegenerative diseases such as Parkinson’s, Alzheimer’s and Huntington’s are products of functional loss in the neural cells (1). Typical techniques used to investigate these diseases lack precise control of the cellular surroundings......, in addition to isolating the neural tissue from nutrient delivery and to creating unwanted gradients (2). This means that typical techniques used to investigate neurodegenerative diseases cannot mimic in vivo conditions, as closely as desired. We have developed a novel microfluidic system for culturing PC12...... cells, neuronal cells, astrocytes cultures and brain slices. The microfluidic system provides efficient nutrient delivery, waste removal, access to oxygen, fine control over the neurochemical environment and access to modern microscopy. Additionally, the setup consists of an in vitro culturing...

Maintenance of mesenchymal stem cells culture due to the cells with reduced attachment rate

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Shuvalova N. S.

2013-01-01

Full Text Available Aim. The classic detachment techniques lead to changes in cells properties. We offer a simple method of cultivating the population of cells that avoided an influence on the surface structures. Methods. Mesenchymal stem cells (MSC from human umbilical cord matrix were obtained and cultivated in standard conditions. While substituting the culture media by a fresh portion, the conditioned culture medium, where the cells were maintained for three days, was transferred to other culture flacks with addition of serum and growth factors. Results. In the flacks, one day after medium transfer, we observed attached cells with typical MSC morphology. The cultures originated from these cells had the same rate of surface markers expression and clonogenic potential as those replated by standard methods. Conclusions. MSC culture, derived by preserving the cells with reduced attachment ability, actually has the properties of «parent» passage. Using this method with accepted techniques of cells reseeding would allow maintaining the cells that avoided an impact on the cell surface proteins.

Evaluation of the osteogenic differentiation of gingiva-derived stem cells grown on culture plates or in stem cell spheroids: Comparison of two- and three-dimensional cultures.

Science.gov (United States)

Lee, Sung-Il; Ko, Youngkyung; Park, Jun-Beom

2017-09-01

Three-dimensional cell culture systems provide a convenient in vitro model for the study of complex cell-cell and cell-matrix interactions in the absence of exogenous substrates. The current study aimed to evaluate the osteogenic differentiation potential of gingiva-derived stem cells cultured in two-dimensional or three-dimensional systems. To the best of our knowledge, the present study is the first to compare the growth of gingiva-derived stem cells in monolayer culture to a three-dimensional culture system with microwells. For three-dimensional culture, gingiva-derived stem cells were isolated and seeded into polydimethylsiloxane-based concave micromolds. Alkaline phosphatase activity and alizarin red S staining assays were then performed to evaluate osteogenesis and the degree of mineralization, respectively. Stem cell spheroids had a significantly increased level of alkaline phosphatase activity and mineralization compared with cells from the two-dimensional culture. In addition, an increase in mineralized deposits was observed with an increase in the loading cell number. The results of present study indicate that gingiva-derived stem cell spheroids exhibit an increased osteogenic potential compared with stem cells from two-dimensional culture. This highlights the potential of three-dimensional culture systems using gingiva-derived stem cells for regenerative medicine applications requiring stem cells with osteogenic potential.

A novel three-dimensional cell culture method enhances antiviral drug screening in primary human cells.

Science.gov (United States)

Koban, Robert; Neumann, Markus; Daugs, Aila; Bloch, Oliver; Nitsche, Andreas; Langhammer, Stefan; Ellerbrok, Heinz

2018-02-01

Gefitinib is a specific inhibitor of the epidermal growth factor receptor (EGFR) and FDA approved for treatment of non-small cell lung cancer. In a previous study we could show the in vitro efficacy of gefitinib for treatment of poxvirus infections in monolayer (2D) cultivated cell lines. Permanent cell lines and 2D cultures, however, are known to be rather unphysiological; therefore it is difficult to predict whether determined effective concentrations or the drug efficacy per se are transferable to the in vivo situation. 3D cell cultures, which meanwhile are widely distributed across all fields of research, are a promising tool for more predictive in vitro investigations of antiviral compounds. In this study the spreading of cowpox virus and the antiviral efficacy of gefitinib were analyzed in primary human keratinocytes (NHEK) grown in a novel 3D extracellular matrix-based cell culture model and compared to the respective monolayer culture. 3D-cultivated NHEK grew in a polarized and thus a more physiological manner with altered morphology and close cell-cell contact. Infected cultures showed a strongly elevated sensitivity towards gefitinib. EGFR phosphorylation, cell proliferation, and virus replication were significantly reduced in 3D cultures at gefitinib concentrations which were at least 100-fold lower than those in monolayer cultures and well below the level of cytotoxicity. Our newly established 3D cell culture model with primary human cells is an easy-to-handle alternative to conventional monolayer cell cultures and previously described more complex 3D cell culture systems. It can easily be adapted to other cell types and a broad spectrum of viruses for antiviral drug screening and many other aspects of virus research under more in vivo-like conditions. In consequence, it may contribute to a more targeted realization of necessary in vivo experiments. Copyright © 2017 Elsevier B.V. All rights reserved.

Mesenchymal stem cells enhance the metastasis of 3D-cultured hepatocellular carcinoma cells

International Nuclear Information System (INIS)

Liu, Chang; Liu, Yang; Xu, Xiao-xi; Guo, Xin; Sun, Guang-wei; Ma, Xiao-jun

2016-01-01

Accumulating evidences have demonstrated that mesenchymal stem cells (MSC) could be recruited to the tumor microenvironment. Umbilical cord mesenchymal stem cells (UCMSC) were attractive vehicles for delivering therapeutic agents against cancer. Nevertheless, the safety of UCMSC in the treatment of tumors including hepatocellular carcinoma (HCC) was still undetermined. In this study, an in vitro co-culture system was established to evaluate the effect of UCMSC on the cell growth, cancer stem cell (CSC) characteristics, drug resistance, metastasis of 3D-cultured HCC cells, and the underlying mechanism was also investigated. It was found that after co-cultured with UCMSC, the metastatic ability of 3D-cultured HCC cells was significantly enhanced as indicated by up-regulation of matrix metalloproteinase (MMP), epithelial-mesenchymal transition (EMT)-related genes, and migration ability. However, cell growth, drug resistance and CSC-related gene expression of HCC cells were not affected by UCMSC. Moreover, EMT was reversed, MMP-2 expression was down-regulated, and migration ability of HCC cell was significantly inhibited when TGF-β receptor inhibitor SB431542 was added into the co-culture system. Therefore, these data indicated that UCMSC could significantly enhance the tumor cell metastasis, which was due to the EMT of HCC cells induced by TGF-β. The online version of this article (doi:10.1186/s12885-016-2595-4) contains supplementary material, which is available to authorized users

Sugar uptake and starch biosynthesis by slices of developing maize endosperm

International Nuclear Information System (INIS)

Felker, F.C.; Liu, Kangchien; Shannon, J.C.

1990-01-01

14 C-Sugar uptake and incorporation into starch by slices of developing maize (Zea mays L.) endosperm were examined and compared with sugar uptake by maize endosperm-derived suspension cultures. Rates of sucrose, fructose, and D- and L-glucose uptake by slices were similar, whereas uptake rates for these sugars differed greatly in suspension cultures. Concentration dependence of sucrose, fructose, and D-glucose uptake was biphasic (consisting of linear plus saturable components) with suspension cultures but linear with slices. These and other differences suggest that endosperm slices are freely permeable to sugars. After diffusion into the slices, sugars were metabolized and incorporated into starch. Starch synthesis, but not sugar accumulation, was greatly reduced by 2.5 millimolar p-chloromercuribenzenesulfonic acid and 0.1 millimolar carbonyl cyanide m-chlorophenylhydrazone. Starch synthesis was dependent on kernel age and incubation temperature, but not on external pH (5 through 8). Competing sugars generally did not affect the distribution of 14 C among the soluble sugars extracted from endosperm slices incubated in 14 C-sugars. Competing hexoses reduced the incorporation of 14 C into starch, but competing sucrose did not, suggesting that sucrose is not a necessary intermediate in starch biosynthesis. The bidirectional permeability of endosperm slices to sugars makes the characterization of sugar transport into endosperm slices impossible, however the model system is useful for experiments dealing with starch biosynthesis which occurs in the metabolically active tissue

Primary Human Uterine Leiomyoma Cell Culture Quality Control: Some Properties of Myometrial Cells Cultured under Serum Deprivation Conditions in the Presence of Ovarian Steroids.

Science.gov (United States)

Bonazza, Camila; Andrade, Sheila Siqueira; Sumikawa, Joana Tomomi; Batista, Fabrício Pereira; Paredes-Gamero, Edgar J; Girão, Manoel J B C; Oliva, Maria Luiza V; Castro, Rodrigo Aquino

2016-01-01

Cell culture is considered the standard media used in research to emulate the in vivo cell environment. Crucial in vivo experiments cannot be conducted in humans and depend on in vitro methodologies such as cell culture systems. However, some procedures involving the quality control of cells in culture have been gradually neglected by failing to acknowledge that primary cells and cell lines change over time in culture. Thus, we report methods based on our experience for monitoring primary cell culture of human myometrial cells derived from uterine leiomyoma. We standardized the best procedure of tissue dissociation required for the study of multiple genetic marker systems that include species-specific antigens, expression of myofibroblast or myoblast markers, growth curve, serum deprivation, starvation by cell cycle synchronization, culture on collagen coated plates, and 17 β-estradiol (E2) and progesterone (P4) effects. The results showed that primary myometrial cells from patients with uterine leiomyoma displayed myoblast phenotypes before and after in vitro cultivation, and leiomyoma cells differentiated into mature myocyte cells under the appropriate differentiation-inducing conditions (serum deprivation). These cells grew well on collagen coated plates and responded to E2 and P4, which may drive myometrial and leiomyoma cells to proliferate and adhere into a focal adhesion complex involvement in a paracrine manner. The establishment of these techniques as routine procedures will improve the understanding of the myometrial physiology and pathogenesis of myometrium-derived diseases such as leiomyoma. Mimicking the in vivo environment of fibrotic conditions can prevent false results and enhance results that are based on cell culture integrity.

Maize kernel antioxidants and their potential involvement in Fusarium ear rot resistance.

Science.gov (United States)

Picot, Adeline; Atanasova-Pénichon, Vessela; Pons, Sebastien; Marchegay, Gisèle; Barreau, Christian; Pinson-Gadais, Laëtitia; Roucolle, Joël; Daveau, Florie; Caron, Daniel; Richard-Forget, Florence

2013-04-10

The potential involvement of antioxidants (α-tocopherol, lutein, zeaxanthin, β-carotene, and ferulic acid) in the resistance of maize varieties to Fusarium ear rot was the focus of this study. These antioxidants were present in all maize kernel stages, indicating that the fumonisin-producing fungi (mainly Fusarium verticillioides and Fusarium proliferatum ) are likely to face them during ear colonization. The effect of these compounds on fumonisin biosynthesis was studied in F. verticillioides liquid cultures. In carotenoid-treated cultures, no inhibitory effect of fumonisin accumulation was observed while a potent inhibitory activity was obtained for sublethal doses of α-tocopherol (0.1 mM) and ferulic acid (1 mM). Using a set of genotypes with moderate to high susceptibility to Fusarium ear rot, ferulic acid was significantly lower in immature kernels of the very susceptible group. Such a relation was nonexistent for tocopherols and carotenoids. Also, ferulic acid in immature kernels ranged from 3 to 8.5 mg/g, i.e., at levels consistent with the in vitro inhibitory concentration. Overall, our data support the fact that ferulic acid may contribute to resistance to Fusarium ear rot and/or fumonisin accumulation.

Radiosensitivity of normal human epidermal cells in culture

International Nuclear Information System (INIS)

Dover, R.; Potten, C.S.

1983-01-01

Using an in vitro culture system the authors have derived #betta#-radiation survival curves over a dose range 0-8 Gy for the clonogenic cells of normal human epidermis. The culture system used allows the epidermal cells to stratify and form a multi-layered sheet of keratinizing cells. The cultures appear to be a very good model for epidermis in vivo. The survival curves show a population which is apparently more sensitive than murine epidermis in vivo. It remains unclear whether this is an intrinsic difference between the species or is a consequence of the in vitro cultivation of the human cells. (author)

Differentiation of oligodendrocyte progenitor cells from dissociated monolayer and feeder-free cultured pluripotent stem cells.

Science.gov (United States)

Yamashita, Tomoko; Miyamoto, Yuki; Bando, Yoshio; Ono, Takashi; Kobayashi, Sakurako; Doi, Ayano; Araki, Toshihiro; Kato, Yosuke; Shirakawa, Takayuki; Suzuki, Yutaka; Yamauchi, Junji; Yoshida, Shigetaka; Sato, Naoya

2017-01-01

Oligodendrocytes myelinate axons and form myelin sheaths in the central nervous system. The development of therapies for demyelinating diseases, including multiple sclerosis and leukodystrophies, is a challenge because the pathogenic mechanisms of disease remain poorly understood. Primate pluripotent stem cell-derived oligodendrocytes are expected to help elucidate the molecular pathogenesis of these diseases. Oligodendrocytes have been successfully differentiated from human pluripotent stem cells. However, it is challenging to prepare large amounts of oligodendrocytes over a short amount of time because of manipulation difficulties under conventional primate pluripotent stem cell culture methods. We developed a proprietary dissociated monolayer and feeder-free culture system to handle pluripotent stem cell cultures. Because the dissociated monolayer and feeder-free culture system improves the quality and growth of primate pluripotent stem cells, these cells could potentially be differentiated into any desired functional cells and consistently cultured in large-scale conditions. In the current study, oligodendrocyte progenitor cells and mature oligodendrocytes were generated within three months from monkey embryonic stem cells. The embryonic stem cell-derived oligodendrocytes exhibited in vitro myelinogenic potency with rat dorsal root ganglion neurons. Additionally, the transplanted oligodendrocyte progenitor cells differentiated into myelin basic protein-positive mature oligodendrocytes in the mouse corpus callosum. This preparative method was used for human induced pluripotent stem cells, which were also successfully differentiated into oligodendrocyte progenitor cells and mature oligodendrocytes that were capable of myelinating rat dorsal root ganglion neurons. Moreover, it was possible to freeze, thaw, and successfully re-culture the differentiating cells. These results showed that embryonic stem cells and human induced pluripotent stem cells maintained in a

Culture and Characterization of Circulating Endothelial Progenitor Cells in Patients with Renal Cell Carcinoma.

Science.gov (United States)

Gu, Wenyu; Sun, Wei; Guo, Changcheng; Yan, Yang; Liu, Min; Yao, Xudong; Yang, Bin; Zheng, Junhua

2015-07-01

Although emerging evidence demonstrates increased circulating endothelial progenitor cells in patients with solid tumors, to our knowledge it is still unknown whether such cells can be cultured from patients with highly angiogenic renal cell carcinoma. We cultured and characterized circulating endothelial progenitor cells from patients with renal cell carcinoma. The circulating endothelial progenitor cell level (percent of CD45(-)CD34(+) VEGF-R2(+) cells in total peripheral blood mononuclear cells) was quantified in 47 patients with renal cell carcinoma and 40 healthy controls. Peripheral blood mononuclear cells were then isolated from 33 patients with renal cell carcinoma and 30 healthy controls to culture and characterize circulating endothelial progenitor cells. The circulating endothelial progenitor cell level was significantly higher in patients with renal cell carcinoma than in healthy controls (0.276% vs 0.086%, p cells first emerged significantly earlier in patient than in control preparations (6.72 vs 14.67 days, p culture success rate (87.8% vs 40.0% of participants) and the number of colonies (10.06 vs 1.83) were significantly greater for patients than for controls (each p cell level correlated positively with the number of patient colonies (r = 0.762, p Cells cultured from patients and controls showed a similar growth pattern, immunophenotype, ability to uptake Ac-LDL and bind lectin, and form capillary tubes in vitro. However, significantly more VEGF-R2(+) circulating endothelial progenitor cells were found in preparations from patients with renal cell carcinoma than from healthy controls (21.1% vs 13.4%, p cell colonies, a higher cell culture success rate and more colonies were found for patients with renal cell carcinoma than for healthy controls. Results indicate the important significance of VEGF-R2(+) circulating endothelial progenitors in patients with renal cell carcinoma. Copyright © 2015 American Urological Association Education and Research

The impact of cell culture equipment on energy loss.

Science.gov (United States)

Davies, Lleucu B; Kiernan, Michael N; Bishop, Joanna C; Thornton, Catherine A; Morgan, Gareth

2014-01-01

Light energy of discrete wavelengths supplied via lasers and broadband intense pulsed light have been used therapeutically for many years. In vitro models complement clinical studies, especially for the elucidation of underlying mechanisms of action. Clarification that light energy reaches the cells is necessary when developing protocols for the treatment of cells using in vitro models. Few studies report on energy loss in cell culture equipment. The ability of energy from light with therapeutic potential to reach cells in culture needs to be determined; this includes determining the proportion of light energy lost within standard cell culture media and cell culture vessels. The energy absorption of cell culture media, with/without the pH indicator dye phenol red, and the loss of energy within different plastics and glassware used typically for in vitro cell culture were investigated using intense pulsed light and a yellow pulsed dye laser. Media containing phenol red have a distinctive absorption peak (560 nm) absent in phenol red-free media and restored by the addition of phenol red. For both light sources, energy loss was lowest in standard polystyrene tissue culture flasks or multi-well plates and highest in polypropylene vessels or glass tubes. The effects of phenol red-free media on the absorption of energy varied with the light source used. Phenol red-free media are the media of choice; polystyrene vessels with flat surfaces such as culture flasks or multi-well plates should be used in preference to polypropylene or glass vessels.

Surface modified alginate microcapsules for 3D cell culture

Science.gov (United States)

Chen, Yi-Wen; Kuo, Chiung Wen; Chueh, Di-Yen; Chen, Peilin

2016-06-01

Culture as three dimensional cell aggregates or spheroids can offer an ideal platform for tissue engineering applications and for pharmaceutical screening. Such 3D culture models, however, may suffer from the problems such as immune response and ineffective and cumbersome culture. This paper describes a simple method for producing microcapsules with alginate cores and a thin shell of poly(L-lysine)-graft-poly(ethylene glycol) (PLL-g-PEG) to encapsulate mouse induced pluripotent stem (miPS) cells, generating a non-fouling surface as an effective immunoisolation barrier. We demonstrated the trapping of the alginate microcapsules in a microwell array for the continuous observation and culture of a large number of encapsulated miPS cells in parallel. miPS cells cultured in the microcapsules survived well and proliferated to form a single cell aggregate. Droplet formation of monodisperse microcapsules with controlled size combined with flow cytometry provided an efficient way to quantitatively analyze the growth of encapsulated cells in a high-throughput manner. The simple and cost-effective coating technique employed to produce the core-shell microcapsules could be used in the emerging field of cell therapy. The microwell array would provide a convenient, user friendly and high-throughput platform for long-term cell culture and monitoring.

A Simple Hydrophilic Treatment of SU-8 Surfaces for Cell Culturing and Cell Patterning

DEFF Research Database (Denmark)

Wang, Zhenyu; Stangegaard, Michael; Dufva, Hans Martin

2005-01-01

SU-8, an epoxy-based photoresist, widely used in constitution different mTAS systems, is incompatible with mammalian cell adhesion and culture in its native form. Here, we demonstrate a simple, cheap and robust two-step method to render a SU-8 surface hydrophilic and compatible with cell culture........ The contact angle of SU-8 surface was significantly reduced from 90° to 25° after the surface modification. The treated SU-8 surfaces provided a cell culture environment that was comparable with cell culture flask surface in terms of generation time and morphology....

Identification of differences in gene expression in primary cell cultures of human endometrial epithelial cells and trophoblast cells following their interaction

DEFF Research Database (Denmark)

Høgh, Mette; Islin, Henrik; Møller, Charlotte

2006-01-01

The interaction between the cell types was simulated in vitro by growing primary cell cultures of human endometrial epithelial cells and trophoblast cells together (co-culture) and separately (control cultures). Gene expression in the cell cultures was compared using the Differential Display method and confirmed...

Establishment of automated culture system for murine induced pluripotent stem cells

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Koike Hiroyuki

2012-11-01

Full Text Available Abstract Background Induced pluripotent stem (iPS cells can differentiate into any cell type, which makes them an attractive resource in fields such as regenerative medicine, drug screening, or in vitro toxicology. The most important prerequisite for these industrial applications is stable supply and uniform quality of iPS cells. Variation in quality largely results from differences in handling skills between operators in laboratories. To minimize these differences, establishment of an automated iPS cell culture system is necessary. Results We developed a standardized mouse iPS cell maintenance culture, using an automated cell culture system housed in a CO2 incubator commonly used in many laboratories. The iPS cells propagated in a chamber uniquely designed for automated culture and showed specific colony morphology, as for manual culture. A cell detachment device in the system passaged iPS cells automatically by dispersing colonies to single cells. In addition, iPS cells were passaged without any change in colony morphology or expression of undifferentiated stem cell markers during the 4 weeks of automated culture. Conclusions Our results show that use of this compact, automated cell culture system facilitates stable iPS cell culture without obvious effects on iPS cell pluripotency or colony-forming ability. The feasibility of iPS cell culture automation may greatly facilitate the use of this versatile cell source for a variety of biomedical applications.

Effect of Bambara nut and cowpea intercropped with maize at different times on nutritive quality of maize for ruminant feeding

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Olanite, J. A.

2017-06-01

Full Text Available Effects of Bambara nut and cowpea planted with maize at different times on nutritive quality of maize forage were investigated. The study was laid out in a Completely Randomized Design and the treatments were combination of crop types (Bambara nut-maize (MB and Cowpea-maize (MC and planting times of legumes (2 wks before planting maize, 2WBPM and 2 wks after planting maize, 2WAPM, and sole maize (as control. An experimental field measuring 19 m � 11 m was divided into 3 replicates; each replicate was sub-divided into 5 plots of dimension 3 m2 each, with 1 m and 2 m inter-plots and inter-blocks spacing respectively. Maize forage samples were harvested on each plot at 10 wks after planting, oven-dried, milled and analyzed to evaluate the chemical composition, mineral composition, in vitro gas production and post-incubation characteristics. Results revealed significant differences (P<0.05 among treatments with the highest (95.00% and least DM (92.12% values were recorded for MB 2WBPM and MC 2WAPM, respectively. CP values ranged from 10.36% in MB 2WBPM to 15.67% in MC 2WBPM but not significantly different from 14.19 % recorded for sole maize. Ash ranged from 7.00% in MB 2WAPM to 10.00% in sole maize. MC 2WBPM and sole maize had the highest (50.63% and least (38.40% in ADF content (P<0.05. ADL value (7.25% observed in MB 2WBPM was the highest, compared to the least (5.00% in sole maize. Sole maize recorded the least (40.40% and highest (25.91% cellulose and hemicellulose contents, respectively while MC 2WAPM had the highest (50.88% and lowest (15.80% values for cellulose and hemicellulose, respectively. Ca content (4.55g/kg of MB 2WAPM was lower than the other treatments. P content ranged from 3.54 g/kg in MB 2WAPM to 12.02 g/kg in MC 2WAPM. Gas production rates only varied (P<0.05 at the 3rd, 6th, 24th and 48th hours of incubation. MB 2WBPM yielded highest values of short chain fatty acids (0.09 �mol and metabolizable energy (3.08 MJ/kg while MB

Youth Culture and Cell Phone

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mohammad saeed zokaei

2009-11-01

Full Text Available Iranian youth’s leisure culture has been immediately affected by the digital media culture. As a communicative media, cell phone has crossed borders of youth norms and identity; and in addition to facilitating their communication, has changed its patterns. Applying Bourdieu’s concepts of habitus and field, and relied on the qualitative and quantitative data gathered from the mobile youth users, the present study argues that mobile has produced a new field in which youth’s opportunities for leisure, entertainment, communication, and independence have extended. In addition, cell phone has facilitated and compensated for some defects in public sphere, and therefore empowered youth agency, individuality, and power. Despite this strengthening, cell phone does not cross borders of gender and class differences, or the levels of social capital.

Modulation of energy homeostasis in maize and Arabidopsis to develop lines tolerant to drought, genotoxic and oxidative stresses

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Elizabeth Njuguna

2018-02-01

Full Text Available Abiotic stresses cause crop losses worldwide that reduce the average yield by more than 50%. Due to the high energy consumed to enhance the respiration rates, the excessive reactive oxygen species release provokes cell death and, ultimately, whole plant decay. A metabolic engineering approach in maize (Zea mays altered the expression of two poly(ADP-ribosylation metabolic pathway proteins, poly(ADP-ribose polymerase (PARP and ADP-ribose-specifIc Nudix hydrolase (NUDX genes that play a role in the maintenance of the energy homeostasis during stresses. By means of RNAi hairpin silencing and CRISPR/Cas9 gene editing strategies, the PARP expression in maize was downregulated or knocked down. The Arabidopsis NUDX7 gene and its two maize homologs, ZmNUDX2 and ZmNUDX8, were overexpressed in maize and Arabidopsis. Novel phenotypes were observed, such as significant tolerance to oxidative stress and improved yield in Arabidopsis and a trend of tolerance to mild drought stress in maize and in Arabidopsis. Key words: poly(ADP-ribose polymerase, Nudix hydrolase, CRISPR/Cas9, maize, oxidative stress, drought stress

Characterization of Indian and exotic quality protein maize (QPM ...

African Journals Online (AJOL)

Polymorphism analysis and genetic diversity of normal maize and quality protein maize (QPM) inbreds among locally well adapted germplasm is a prerequisite for hybrid maize breeding program. The diversity analyses of 48 maize accessions including Indian and exotic germplasm using 75 simple sequence repeat (SSR) ...

Primary Human Uterine Leiomyoma Cell Culture Quality Control: Some Properties of Myometrial Cells Cultured under Serum Deprivation Conditions in the Presence of Ovarian Steroids.

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Camila Bonazza

Full Text Available Cell culture is considered the standard media used in research to emulate the in vivo cell environment. Crucial in vivo experiments cannot be conducted in humans and depend on in vitro methodologies such as cell culture systems. However, some procedures involving the quality control of cells in culture have been gradually neglected by failing to acknowledge that primary cells and cell lines change over time in culture. Thus, we report methods based on our experience for monitoring primary cell culture of human myometrial cells derived from uterine leiomyoma. We standardized the best procedure of tissue dissociation required for the study of multiple genetic marker systems that include species-specific antigens, expression of myofibroblast or myoblast markers, growth curve, serum deprivation, starvation by cell cycle synchronization, culture on collagen coated plates, and 17 β-estradiol (E2 and progesterone (P4 effects. The results showed that primary myometrial cells from patients with uterine leiomyoma displayed myoblast phenotypes before and after in vitro cultivation, and leiomyoma cells differentiated into mature myocyte cells under the appropriate differentiation-inducing conditions (serum deprivation. These cells grew well on collagen coated plates and responded to E2 and P4, which may drive myometrial and leiomyoma cells to proliferate and adhere into a focal adhesion complex involvement in a paracrine manner. The establishment of these techniques as routine procedures will improve the understanding of the myometrial physiology and pathogenesis of myometrium-derived diseases such as leiomyoma. Mimicking the in vivo environment of fibrotic conditions can prevent false results and enhance results that are based on cell culture integrity.

Screening of different insecticides against maize shoot fly atherigona soccata (Rond.) and maize borer. chilo partellus (swinh.)

International Nuclear Information System (INIS)

Shahid, M.A.; Rana, Z.A.; Haq, I.; Tariq, H.

2010-01-01

Field studies were carried out in the research area of the Ayub Agricultural Research Institute, Faisalabad to determine the most effective maize seed treatment against maize shoot fly Atherigona soccata (Rond.) and insecticide against maize borer Chilo partellus (Swinh.) Trials were conducted following RCBD and replicated three times during 2005-2006. Two seed treatments Confider (imidacloprid) 70 WS and pensidor 72% WP (5 and 7 mg/kg seed) along with Confider (imidaclorid) 200 SC at the rate 40 ml/acre in the trial against maize shoot fly whereas, flubendiamide 48%, emamection 1.9 EC, spinosad 240 EC. carbofuran 3 G, indoxacarb 150 SC, alphacypermethrine 20 EC, monomehypo 5 G, bifenthrin 10 EC, cartap 4G, cyhalothrine 2.5 EC, cypermethrin 10 EC at the rate 20 ml, 150 ml, 40 ml, 8 kg, 150 ml, 200 ml, 5 kg, 150 ml, 6 kg. 250 ml and 300 ml per acre against maize borer were treated keeping one plo ast untreated check. Treatments were repeated as borer infestation reached above 5% level. All the seed treatments showed significant control of maize shoot fly in spite of dose 5 or 7 mg/kg seed along with foliar spray of confider 200 SC. The insecticides viz. flubendiamide 48% SC. emamectin 1.9 EC, spinosad 240 EC and carbofuran 3 G. indoxacarb 150 SC. alpha cypermethrin 20 EC, not only responded highest yield 5765, 5294, 5289, 5215, 5168 and 5025 kg/ha respectively but also manage the maize borer below ETL. (author)

A(maize)ing attraction: gravid Anopheles arabiensis are attracted and oviposit in response to maize pollen odours.

Science.gov (United States)

Wondwosen, Betelehem; Hill, Sharon R; Birgersson, Göran; Seyoum, Emiru; Tekie, Habte; Ignell, Rickard

2017-01-23

Maize cultivation contributes to the prevalence of malaria mosquitoes and exacerbates malaria transmission in sub-Saharan Africa. The pollen from maize serves as an important larval food source for Anopheles mosquitoes, and females that are able to detect breeding sites where maize pollen is abundant may provide their offspring with selective advantages. Anopheles mosquitoes are hypothesized to locate, discriminate among, and select such sites using olfactory cues, and that synthetic volatile blends can mimic these olfactory-guided behaviours. Two-port olfactometer and two-choice oviposition assays were used to assess the attraction and oviposition preference of gravid Anopheles arabiensis to the headspace of the pollen from two maize cultivars (BH-660 and ZM-521). Bioactive compounds were identified using combined gas chromatography and electroantennographic detection from the headspace of the cultivar found to be most attractive (BH-660). Synthetic blends of the volatile compounds were then assessed for attraction and oviposition preference of gravid An. arabiensis, as above. Here the collected headspace volatiles from the pollen of two maize cultivars was shown to differentially attract and stimulate oviposition in gravid An. arabiensis. Furthermore, a five-component synthetic maize pollen odour blend was identified, which elicited the full oviposition behavioural repertoire of the gravid mosquitoes. The cues identified from maize pollen provide important substrates for the development of novel control measures that modulate gravid female behaviour. Such measures are irrespective of indoor or outdoor feeding and resting patterns, thus providing a much-needed addition to the arsenal of tools that currently target indoor biting mosquitoes.

Applying CSM-CERES-Maize to define a sowing window for irrigated maize crop - The Riacho´s Farm case study

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Denise Freitas Silva

2011-08-01

Full Text Available Irrigation use constitutes an alternative to improve maize production in Central Minas Gerais State, Brazil. However, even under adequate water supply conditions, other environmental factors may influence maize crop growth and development and may, ultimately, affect grain yield. This study aimed to establish a sowing window for irrigated maize crop, based on simulation results obtained with the decision support model CSM-CERES-Maize. Simulations were made for crop management conditions of Riacho´s Farm, located in Matozinhos, Minas Gerais State, Brazil. It was employed the model´s seasonal tool, along with a data set containing 46 years of weather data records, to simulate maize yield for weekly sowing scenarios, starting on August 1st and ending on July 24th of each year. One defined an irrigated maize sowing window, taking into account the yield break risk that a farmer would be willing to take. The model proved to be an interesting tool to assist in decision making, regarding crop and irrigation management, for an irrigated maize production system. Assuming a 10% yield break in the expected average maximum maize yield, it was defined as sowing window, the period from January 23rd to March 6th, with February 20th as the best sowing date. Other sowing windows may be established according to the risk that the farmer would be willing to take.

Status and prospects of maize research in Nepal

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Govind KC

2015-12-01

Full Text Available Food and nutritional securities are the major threats coupled with declining factor productivity and climate change effects in Nepal. Maize being the principal food crops of the majority of the hill people and source of animal feed for ever growing livestock industries in Terai of Nepal. Despite the many efforts made to increase the maize productivity in the country, the results are not much encouraging. Many of the maize based technologies developed and recommended for the farmers to date are not fully adopted. Therefore, problem is either on technology development or on dissemination or on both. Considering the above facts, some of the innovative and modern approaches of plant breeding and crop management technologies to increase the maize yield need to be developed and disseminated. There is a need for location-specific maize production technologies, especially for lowland winter maize, marginal upland maize production system, and resource poor farmers. Research efforts can be targeted to address both yield potential and on-farm yields by reducing the impacts of abiotic and biotic constraints. Therefore, in order to streamline the future direction of maize research in Nepal, an attempt has been made in this article to highlight the present status and future prospects with few key pathways.

Effect of Different Arbuscular Mycorrhizal Fungi on Growth and Physiology of Maize at Ambient and Low Temperature Regimes

Directory of Open Access Journals (Sweden)

Xiaoying Chen

2014-01-01

Full Text Available The effect of four different arbuscular mycorrhizal fungi (AMF on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress.

Comparative study of the radionuclide uptake and distribution within plants for barley and maize varieties

International Nuclear Information System (INIS)

Kostyuk, O.

1998-01-01

Differences in the Cs-134 and Sr-85 uptake by three barley and two maize varieties were investigated in a water culture experiment. In barley, the maximum differences were about 30% for cesium and 50% for strontium. The differences between the maize varieties were negligible. The maximum difference between the varieties of the two species of crops was approximately 30% for cesium and 1 70% for strontium with higher radionuclide uptake by maize. All barley varieties accumulated cesium nearly 3.5 times more effectively than strontium, whereas for the maize varieties, cesium was accumulated about 2 times more effectively. There is a large difference in the radionuclide distribution within the plants: the amount of radiocesium in the green part of plants of both species was approximately 30% of the total, while for radiostrontium it was about 80%. As a result, approximately the same amount of the radionuclides were present in the green part of plants, despite the large difference in the uptake of the radionuclides by the whole plants. It is concluded that crop selection as a provision to reduce radionuclide contamination of the food chain should only be applied taking into account the different radionuclide distributions within the plants

Zygotic Genome Activation Occurs Shortly after Fertilization in Maize.

Science.gov (United States)

Chen, Junyi; Strieder, Nicholas; Krohn, Nadia G; Cyprys, Philipp; Sprunck, Stefanie; Engelmann, Julia C; Dresselhaus, Thomas

2017-09-01

The formation of a zygote via the fusion of an egg and sperm cell and its subsequent asymmetric division herald the start of the plant's life cycle. Zygotic genome activation (ZGA) is thought to occur gradually, with the initial steps of zygote and embryo development being primarily maternally controlled, and subsequent steps being governed by the zygotic genome. Here, using maize ( Zea mays ) as a model plant system, we determined the timing of zygote development and generated RNA-seq transcriptome profiles of gametes, zygotes, and apical and basal daughter cells. ZGA occurs shortly after fertilization and involves ∼10% of the genome being activated in a highly dynamic pattern. In particular, genes encoding transcriptional regulators of various families are activated shortly after fertilization. Further analyses suggested that chromatin assembly is strongly modified after fertilization, that the egg cell is primed to activate the translational machinery, and that hormones likely play a minor role in the initial steps of early embryo development in maize. Our findings provide important insights into gamete and zygote activity in plants, and our RNA-seq transcriptome profiles represent a comprehensive, unique RNA-seq data set that can be used by the research community. © 2017 American Society of Plant Biologists. All rights reserved.

Cell culture density affects the proliferation activity of human adipose tissue stem cells.

Science.gov (United States)

Kim, Dae Seong; Lee, Myoung Woo; Ko, Young Jong; Chun, Yong Hoon; Kim, Hyung Joon; Sung, Ki Woong; Koo, Hong Hoe; Yoo, Keon Hee

2016-01-01

In this study, we investigated the effect of cell density on the proliferation activity of human mesenchymal stem cells (MSCs) derived from adipose tissue (AT-MSCs) over time in culture. Passage #4 (P4) and #12 (P12) AT-MSCs from two donors were plated at a density of 200 (culture condition 1, CC1) or 5000 (culture condition 2, CC2) cells cm(-2) . After 7 days of incubation, P4 and P12 AT-MSCs cultured in CC1 were thin and spindle-shaped, whereas those cultured in CC2 had extensive cell-to-cell contacts and an expanded cell volume. In addition, P4 and P12 AT-MSCs in CC1 divided more than three times, while those in CC2 divided less than once on average. Flow cytometric analysis using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester dye showed that the fluorescence intensity of AT-MSCs was lower in CC1 than in CC2. Furthermore, expression of proliferation-associated genes, such as CDC45L, CDC20A and KIF20A, in P4 AT-MSCs was higher in CC1 than in CC2, and this difference was also observed in P12 AT-MSCs. These data demonstrated that cell culture density affects the proliferation activity of MSCs, suggesting that it is feasible to design a strategy to prepare suitable MSCs using specific culture conditions. Copyright © 2016 John Wiley & Sons, Ltd.

Nanotechnology, Cell Culture and Tissue Engineering

Directory of Open Access Journals (Sweden)

Kazutoshi Haraguchi

2011-01-01

Full Text Available We have fabricated new types of polymer hydrogels and polymer nanocomposites, i.e., nanocomposite gels (NC gels and soft, polymer nanocomposites (M-NCs: solid, with novel organic/inorganic network structures. Both NC gels and M-NCs were synthesized by in-situ free-radical polymerization in the presence of exfoliated clay platelets in aqueous systems and were obtained in various forms such as film, sheet, tube, coating, etc. and sizes with a wide range of clay contents. Here, disk-like inorganic clay nanoparticles act as multi-functional crosslinkers to form new types of network systems. Both NC gels and M-NCs have extraordinary optical and mechanical properties including ultra-high reversible extensibility, as well as a number of new characteristics relating to optical anisotropy, polymer/clay morphology, biocompatibility, stimuli-sensitive surfaces, micro-patterning, etc. For examples, the biological testing of medical devices, comprised of a sensitization test, an irritation test, an intracutaneous test and an in vitro cytotoxicity test,was carried out for NC gels and M-NCs. The safety of NC gels and M-NCs was confirmed in all tests. Also, the interaction of living tissue with NC gel was investigated in vivo by implantation in live goats; neither inflammation nor concrescence occurred around the NC gels. Furthermore, it was found that both N-NC gels consisting of poly(N-isopropylacrylamide(PNIPA/clay network and M-NCs consisting of poly(2-methoxyethyacrylate(PMEA/clay network show characteristic cell culture and subsequent cell detachment on their surfaces, although it was almost impossible to culture cells on conventional, chemically-crosslinked PNIPA hydrogels and chemically crossslinked PMEA, regardless of their crosslinker concentration. Various kinds of cells, such ashumanhepatoma cells (HepG2, normal human dermal fibroblast (NHDF, and human umbilical vein endothelial cells (HUVEC, could be cultured to be confluent on the surfaces of N

The mechanisms of root exudates of maize in improvement of iron nutrition of peanut in peanut/maize intercropping system by 14C tracer technique

International Nuclear Information System (INIS)

Zuo Yuanmei; Chen Qing; Zhang Fusuo

2004-01-01

The related mechanisms of root exudates of maize in improvement iron nutrition of peanut intercropped with maize was investigated by 14 C tracer technique. Neighboring roots between maize and peanut were separated by a 30 μm nylon net, the iron nutrition of peanut was also improved just like normal intercropping of maize and peanut. The results proved that root exudates of maize played an important role in improvement iron nutrition of peanut. The photosynthesis carbohydrate of maize could exuded into the rhizosphere of peanut and transfer into shoot and root of peanut in intercropping system. Root exudates of maize could increased efficiency of iron in soil and improved iron utilization of peanut

Selection for drought tolerance in two tropical maize populations ...

African Journals Online (AJOL)

Drought is a major factor limiting maize (Zea mays L.) yield in much of the world. The need to breed maize cultivars with improved drought tolerance is apparent. This study compared two maize populations, ZM601 and ZM607 for drought tolerance during flowering, the most drought-vulnerable period for the maize plant.

Recombinant Protein Production and Insect Cell Culture and Process

Science.gov (United States)

Spaulding, Glenn F. (Inventor); Goodwin, Thomas J. (Inventor); OConnor, Kim C. (Inventor); Francis, Karen M. (Inventor); Andrews, Angela D. (Inventor); Prewett, Tracey L. (Inventor)

1997-01-01

A process has been developed for recombinant production of selected polypeptides using transformed insect cells cultured in a horizontally rotating culture vessel modulated to create low shear conditions. A metabolically transformed insect cell line is produced using the culture procedure regardless of genetic transformation. The recombinant polypeptide can be produced by an alternative process using virtually infected or stably transformed insect cells containing a gene encoding the described polypeptide. The insect cells can also be a host for viral production.

Effects of maize planting patterns on the performance of cassava ...

African Journals Online (AJOL)

sola

The design was a split-plot arrangement, laid out in a randomized ... significant differences (P<0.05) between the treatments in the growth and yield parameters of maize. The mean effects of companion crops on maize leaf area were 0.61, 0.60, 0.60 and 0.52 m2/plant for sole maize, maize / melon, maize / cassava and.

Metabolite profiling of microfluidic cell culture conditions for droplet based screening

DEFF Research Database (Denmark)

Björk, Sara M.; Sjoström, Staffan L.; Svahn, Helene Andersson

2015-01-01

We investigate the impact of droplet culture conditions on cell metabolic state by determining key metabolite concentrations in S. cerevisiae cultures in different microfluidic droplet culture formats. Control of culture conditions is critical for single cell/clone screening in droplets......, such as directed evolution of yeast, as cell metabolic state directly affects production yields from cell factories. Here, we analyze glucose, pyruvate, ethanol, and glycerol, central metabolites in yeast glucose dissimilation to establish culture formats for screening of respiring as well as fermenting yeast...... limited cultures, whereas the metabolite profiles of cells cultured in the alternative wide tube droplet incubation format resemble those from aerobic culture. Furthermore, we demonstrate retained droplet stability and size in the new better oxygenated droplet incubation format....

Developing Inset Resistant Maize Varieties for Food Security in Kenya

International Nuclear Information System (INIS)

Mugo, S.

2002-01-01

The Insect Resistant Maize for Africa (IRMA) project aims at increasing maize production and food security through development and deployment of stem borer resistant maize germplasm developed using conventional and through biotechnology methods such as Bt maize. Bt maize offers farmers an effective and practical option for controlling stem borers. It was recognized that the development and routine use of Bt maize will require addressing relevant bio-safety, environmental, and community concerns and research and information gathering activities are in place to address these concerns and research and information gathering activities are in place to address these concerns. Suitable Bt gene have been acquired or synthesized and back-crossed into elite maize germplasm at CIMMYT-Mexico, and the effective Cry-proteins against the major maize stem borers in Kenya were identified to better target pests. Stem borer resistant maize germplasm is being developed through conventional breeding, using locally adapted and exotic germplasm. for safe and effective deployment of Bt maize,studies on its impacts on target and non-target arthropods as well as studies on the effects of Bt maize on key non-target arthropods as well as studies on gene flow are underway. Insect resistance management strategies are being developed through quantifying the effectiveness, ???. Socioeconomic impact studies are revealing factors in the society that may influence the adoption of Bt maize in Kenya. Also, baseline data, essential for the monitoring and evaluation of the Bt maize technology in Kenya, has been established. Technology transfer and capacity building, creating awareness and communications have received attention in the project. This paper describes the major research activities as they relate to development of the stem bore resistant maize germplasm

A Cell Culture Approach to Optimized Human Corneal Endothelial Cell Function

Science.gov (United States)

Bartakova, Alena; Kuzmenko, Olga; Alvarez-Delfin, Karen; Kunzevitzky, Noelia J.; Goldberg, Jeffrey L.

2018-01-01

Purpose Cell-based therapies to replace corneal endothelium depend on culture methods to optimize human corneal endothelial cell (HCEC) function and minimize endothelial-mesenchymal transition (EnMT). Here we explore contribution of low-mitogenic media on stabilization of phenotypes in vitro that mimic those of HCECs in vivo. Methods HCECs were isolated from cadaveric donor corneas and expanded in vitro, comparing continuous presence of exogenous growth factors (“proliferative media”) to media without those factors (“stabilizing media”). Identity based on canonical morphology and expression of surface marker CD56, and function based on formation of tight junction barriers measured by trans-endothelial electrical resistance assays (TEER) were assessed. Results Primary HCECs cultured in proliferative media underwent EnMT after three to four passages, becoming increasingly fibroblastic. Stabilizing the cells before each passage by switching them to a media low in mitogenic growth factors and serum preserved canonical morphology and yielded a higher number of cells. HCECs cultured in stabilizing media increased both expression of the identity marker CD56 and also tight junction monolayer integrity compared to cells cultured without stabilization. Conclusions HCECs isolated from donor corneas and expanded in vitro with a low-mitogenic media stabilizing step before each passage demonstrate more canonical structural and functional features and defer EnMT, increasing the number of passages and total canonical cell yield. This approach may facilitate development of HCEC-based cell therapies. PMID:29625488

RESPONSIVENESS OF SPATIAL PRICE VOLATILITY TO INCREASED GOVERNMENT PARTICIPATION IN MAIZE GRAIN AND MAIZE MEAL MARKETING IN ZAMBIA

OpenAIRE

Syampaku, E.M; Mafimisebi, Taiwo Ejiola

2014-01-01

The study analyzed the responsiveness of maize grain and maize meal spatial price volatilities to increased government participation in maize grain marketing in Zambia using descriptive statistics and vector auto-regression (VAR). This was achieved by comparing spatial price volatility means and spatial price means for the period under increased government participation with respective means for periods under limited government participation. Also, spatial price volatilities were regressed ag...

Sponge cell culture? A molecular identification method for sponge cells

NARCIS (Netherlands)

Sipkema, D.; Heilig, G.H.J.; Akkermans, A.D.L.; Osinga, R.; Tramper, J.; Wijffels, R.H.

2003-01-01

Dissociated sponge cells are easily confused with unicellular organisms. This has been an obstacle in the development of sponge-cell lines. We developed a molecular detection method to identify cells of the sponge Dysidea avara in dissociated cell cultures. The 18S ribosomal RNA gene from a Dysidea

Culturing bone marrow cells with dexamethasone and ascorbic acid improves osteogenic cell sheet structure.

Science.gov (United States)

Akahane, M; Shimizu, T; Kira, T; Onishi, T; Uchihara, Y; Imamura, T; Tanaka, Y

2016-11-01

To assess the structure and extracellular matrix molecule expression of osteogenic cell sheets created via culture in medium with both dexamethasone (Dex) and ascorbic acid phosphate (AscP) compared either Dex or AscP alone. Osteogenic cell sheets were prepared by culturing rat bone marrow stromal cells in a minimal essential medium (MEM), MEM with AscP, MEM with Dex, and MEM with Dex and AscP (Dex/AscP). The cell number and messenger (m)RNA expression were assessed in vitro, and the appearance of the cell sheets was observed after mechanical retrieval using a scraper. β-tricalcium phosphate (β-TCP) was then wrapped with the cell sheets from the four different groups and subcutaneously implanted into rats. After mechanical retrieval, the osteogenic cell sheets from the MEM, MEM with AscP, and MEM with Dex groups appeared to be fragmented or incomplete structures. The cell sheets cultured with Dex/AscP remained intact after mechanical retrieval, without any identifiable tears. Culture with Dex/AscP increased the mRNA and protein expression of extracellular matrix proteins and cell number compared with those of the other three groups. More bridging bone formation was observed after transplantation of the β-TCP scaffold wrapped with cell sheets cultured with Dex/AscP, than in the other groups. These results suggest that culture with Dex/AscP improves the mechanical integrity of the osteogenic cell sheets, allowing retrieval of the confluent cells in a single cell sheet structure. This method may be beneficial when applied in cases of difficult tissue reconstruction, such as nonunion, bone defects, and osteonecrosis.Cite this article: M. Akahane, T. Shimizu, T. Kira, T. Onishi, Y. Uchihara, T. Imamura, Y. Tanaka. Culturing bone marrow cells with dexamethasone and ascorbic acid improves osteogenic cell sheet structure. Bone Joint Res 2016;5:569-576. DOI: 10.1302/2046-3758.511.BJR-2016-0013.R1. © 2016 Akahane et al.

Biotechnology in maize breeding

Directory of Open Access Journals (Sweden)

Mladenović-Drinić Snežana

2004-01-01

Full Text Available Maize is one of the most important economic crops and the best studied and most tractable genetic system among monocots. The development of biotechnology has led to a great increase in our knowledge of maize genetics and understanding of the structure and behaviour of maize genomes. Conventional breeding practices can now be complemented by a number of new and powerful techniques. Some of these often referred to as molecular methods, enable scientists to see the layout of the entire genome of any organism and to select plants with preferred characteristics by "reading" at the molecular level, saving precious time and resources. DNA markers have provided valuable tools in various analyses ranging from phylogenetic analysis to the positional cloning of genes. Application of molecular markers for genetic studies of maize include: assessment of genetic variability and characterization of germ plasm, identification and fingerprinting of genotypes, estimation of genetic distance, detection of monogamic and quantitative trait loci, marker assisted selection, identification of sequence of useful candidate genes, etc. The development of high-density molecular maps which has been facilitated by PCR-based markers, have made the mapping and tagging of almost any trait possible and serve as bases for marker assisted selection. Sequencing of maize genomes would help to elucidate gene function, gene regulation and their expression. Modern biotechnology also includes an array of tools for introducing or deieting a particular gene or genes to produce plants with novel traits. Development of informatics and biotechnology are resulted in bioinformatic as well as in expansion of microarrey technique. Modern biotechnologies could complement and improve the efficiency of traditional selection and breeding techniques to enhance agricultural productivity.

21st Century Cell Culture for 21st Century Toxicology.

Science.gov (United States)

Pamies, David; Hartung, Thomas

2017-01-17

There is no good science in bad models. Cell culture is especially prone to artifacts. A number of novel cell culture technologies have become more broadly available in the 21st century, which allow overcoming limitations of traditional culture and are more physiologically relevant. These include the use of stem-cell derived human cells, cocultures of different cell types, scaffolds and extracellular matrices, perfusion platforms (such as microfluidics), 3D culture, organ-on-chip technologies, tissue architecture, and organ functionality. The physiological relevance of such models is further enhanced by the measurement of biomarkers (e.g., key events of pathways), organ specific functionality, and more comprehensive assessment cell responses by high-content methods. These approaches are still rarely combined to create microphysiological systems. The complexity of the combination of these technologies can generate results closer to the in vivo situation but increases the number of parameters to control, bringing some new challenges. In fact, we do not argue that all cell culture needs to be that sophisticated. The efforts taken are determined by the purpose of our experiments and tests. If only a very specific molecular target to cell response is of interest, a very simple model, which reflects this, might be much more suited to allow standardization and high-throughput. However, the less defined the end point of interest and cellular response are, the better we should approximate organ- or tissue-like culture conditions to make physiological responses more probable. Besides these technologic advances, important progress in the quality assurance and reporting on cell cultures as well as the validation of cellular test systems brings the utility of cell cultures to a new level. The advancement and broader implementation of Good Cell Culture Practice (GCCP) is key here. In toxicology, this is a major prerequisite for meaningful and reliable results, ultimately

Microfluidic perfusion culture of human induced pluripotent stem cells under fully defined culture conditions.

Science.gov (United States)

Yoshimitsu, Ryosuke; Hattori, Koji; Sugiura, Shinji; Kondo, Yuki; Yamada, Rotaro; Tachikawa, Saoko; Satoh, Taku; Kurisaki, Akira; Ohnuma, Kiyoshi; Asashima, Makoto; Kanamori, Toshiyuki

2014-05-01

Human induced pluripotent stem cells (hiPSCs) are a promising cell source for drug screening. For this application, self-renewal or differentiation of the cells is required, and undefined factors in the culture conditions are not desirable. Microfluidic perfusion culture allows the production of small volume cultures with precisely controlled microenvironments, and is applicable to high-throughput cellular environment screening. Here, we developed a microfluidic perfusion culture system for hiPSCs that uses a microchamber array chip under defined extracellular matrix (ECM) and culture medium conditions. By screening various ECMs we determined that fibronectin and laminin are appropriate for microfluidic devices made out of the most popular material, polydimethylsiloxane (PDMS). We found that the growth rate of hiPSCs under pressure-driven perfusion culture conditions was higher than under static culture conditions in the microchamber array. We applied our new system to self-renewal and differentiation cultures of hiPSCs, and immunocytochemical analysis showed that the state of the hiPSCs was successfully controlled. The effects of three antitumor drugs on hiPSCs were comparable between microchamber array and 96-well plates. We believe that our system will be a platform technology for future large-scale screening of fully defined conditions for differentiation cultures on integrated microfluidic devices. © 2013 Wiley Periodicals, Inc.

Quantitative volumetric Raman imaging of three dimensional cell cultures

Science.gov (United States)

Kallepitis, Charalambos; Bergholt, Mads S.; Mazo, Manuel M.; Leonardo, Vincent; Skaalure, Stacey C.; Maynard, Stephanie A.; Stevens, Molly M.

2017-03-01

The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell-material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy.

Genomic-based-breeding tools for tropical maize improvement.

Science.gov (United States)

Chakradhar, Thammineni; Hindu, Vemuri; Reddy, Palakolanu Sudhakar

2017-12-01

Maize has traditionally been the main staple diet in the Southern Asia and Sub-Saharan Africa and widely grown by millions of resource poor small scale farmers. Approximately, 35.4 million hectares are sown to tropical maize, constituting around 59% of the developing worlds. Tropical maize encounters tremendous challenges besides poor agro-climatic situations with average yields recorded <3 tones/hectare that is far less than the average of developed countries. On the contrary to poor yields, the demand for maize as food, feed, and fuel is continuously increasing in these regions. Heterosis breeding introduced in early 90 s improved maize yields significantly, but genetic gains is still a mirage, particularly for crop growing under marginal environments. Application of molecular markers has accelerated the pace of maize breeding to some extent. The availability of array of sequencing and genotyping technologies offers unrivalled service to improve precision in maize-breeding programs through modern approaches such as genomic selection, genome-wide association studies, bulk segregant analysis-based sequencing approaches, etc. Superior alleles underlying complex traits can easily be identified and introgressed efficiently using these sequence-based approaches. Integration of genomic tools and techniques with advanced genetic resources such as nested association mapping and backcross nested association mapping could certainly address the genetic issues in maize improvement programs in developing countries. Huge diversity in tropical maize and its inherent capacity for doubled haploid technology offers advantage to apply the next generation genomic tools for accelerating production in marginal environments of tropical and subtropical world. Precision in phenotyping is the key for success of any molecular-breeding approach. This article reviews genomic technologies and their application to improve agronomic traits in tropical maize breeding has been reviewed in

[Effects of light intensities after anthesis on the photosynthetic characteristics and chloroplast ultrastructure in mesophyll cell of summer maize (Zea mays L. )].

Science.gov (United States)

Gao, Jia; Cui, Hai Yan; Shi, Jian Guo; Dong, Shu Ting; Liu, Peng; Zhao, Bin; Zhang, Ji Wang

2018-03-01

We examined the changes of photosynthetic characteristics and chloroplast ultrastructure in mesophyll cell of summer maize in response to different light intensities in the field, with the summer maize hybrid Denghai 605 as experimental material. Two treatments of both shading (S) and increasing light (L) from flowering to physiological maturity stage were designed, with the ambient sunlight treatment as control (CK). Under shading treatment, poorly developed thylakoid structure, blurry lamellar structure, loose granum, large gap between slices and warping granum were the major characteristics in chloroplast. Meanwhile, photosynthetic rate (P n ), transpiration rate, stomatal conductance, chlorophyll content, and actual photo-chemical efficiency (Φ PSII ) decreased, whereas the maximal photochemical efficiency and non-photochemical quenching increased, which resulted in decreases in grain yield under shading treatment. However, a better development was observed in chloroplasts for L treatment, with the number of grana and lamellae increased and lamellae arranged compactly. In addition, P n and Φ PSII increased under L treatment, which increased grain yield. The chloroplast arrangement dispersed in mesophyll cells and chloroplast ultrastructure was destroyed after shading, and then chlorophyll synthesis per unit leaf area and photosynthetic capacity decreased. In contrast, the number of grana and lamellae increased and lamellae arranged compactly after increasing light, which are beneficial for corn yield.

The Effect of Primary Cancer Cell Culture Models on the Results of Drug Chemosensitivity Assays: The Application of Perfusion Microbioreactor System as Cell Culture Vessel

Science.gov (United States)

Chen, Yi-Dao; Huang, Shiang-Fu; Wang, Hung-Ming

2015-01-01

To precisely and faithfully perform cell-based drug chemosensitivity assays, a well-defined and biologically relevant culture condition is required. For the former, a perfusion microbioreactor system capable of providing a stable culture condition was adopted. For the latter, however, little is known about the impact of culture models on the physiology and chemosensitivity assay results of primary oral cavity cancer cells. To address the issues, experiments were performed. Results showed that minor environmental pH change could significantly affect the metabolic activity of cells, demonstrating the importance of stable culture condition for such assays. Moreover, the culture models could also significantly influence the metabolic activity and proliferation of cells. Furthermore, the choice of culture models might lead to different outcomes of chemosensitivity assays. Compared with the similar test based on tumor-level assays, the spheroid model could overestimate the drug resistance of cells to cisplatin, whereas the 2D and 3D culture models might overestimate the chemosensitivity of cells to such anticancer drug. In this study, the 3D culture models with same cell density as that in tumor samples showed comparable chemosensitivity assay results as the tumor-level assays. Overall, this study has provided some fundamental information for establishing a precise and faithful drug chemosensitivity assay. PMID:25654105

Bags versus flasks: a comparison of cell culture systems for the production of dendritic cell-based immunotherapies.

Science.gov (United States)

Fekete, Natalie; Béland, Ariane V; Campbell, Katie; Clark, Sarah L; Hoesli, Corinne A

2018-04-19

In recent years, cell-based therapies targeting the immune system have emerged as promising strategies for cancer treatment. This review summarizes manufacturing challenges related to production of antigen presenting cells as a patient-tailored cancer therapy. Understanding cell-material interactions is essential because in vitro cell culture manipulations to obtain mature antigen-producing cells can significantly alter their in vivo performance. Traditional antigen-producing cell culture protocols often rely on cell adhesion to surface-treated hydrophilic polystyrene flasks. More recent commercial and investigational cancer immunotherapy products were manufactured using suspension cell culture in closed hydrophobic fluoropolymer bags. The shift to closed cell culture systems can decrease risks of contamination by individual operators, as well as facilitate scale-up and automation. Selecting closed cell culture bags over traditional open culture systems entails different handling procedures and processing controls, which can affect product quality. Changes in culture vessels also entail changes in vessel materials and geometry, which may alter the cell microenvironment and resulting cell fate decisions. Strategically designed culture systems will pave the way for the generation of more sophisticated and highly potent cell-based cancer vaccines. As an increasing number of cell-based therapies enter the clinic, the selection of appropriate cell culture vessels and materials becomes a critical consideration that can impact the therapeutic efficacy of the product, and hence clinical outcomes and patient quality of life. © 2018 The Authors Transfusion published by Wiley Periodicals, Inc. on behalf of AABB.

Maize (Zea mays L.).

Science.gov (United States)

Frame, Bronwyn; Warnberg, Katey; Main, Marcy; Wang, Kan

2015-01-01

Agrobacterium tumefaciens-mediated transformation is an effective method for introducing genes into maize. In this chapter, we describe a detailed protocol for genetic transformation of the maize genotype Hi II. Our starting plant material is immature embryos cocultivated with an Agrobacterium strain carrying a standard binary vector. In addition to step-by-step laboratory transformation procedures, we include extensive details in growing donor plants and caring for transgenic plants in the greenhouse.

Studies on the secretion of maize root-cap slime. Pt. 3

International Nuclear Information System (INIS)

Paull, R.E.; Jones, R.L.

1975-01-01

Autoradiography was used to localize the sites of incorporation of L-[ 3 H]fucose into root tips of maize (Zea mays L. cv. S.X. 17). By light microscopy, accumulation of label from [ 3 H]fucose could be seen in the peripheral cells of the root cap. Extraction of sections prepared by freeze-substitution showed that most of the label in the cytoplasm of peripheral root-cap cells is water-soluble whereas label associated with the wall is sodium-hydroxide-soluble. In the electron microscope, glutaraldehyde-fixed peripheral cells of maize root caps are characterized by the presence of numerous dictyosomes and vesicles. The distended dictyosome cisternae and vesicles have large deposits of silver after staining with periodic acid-silver methanamine. An accumulation of material similar to that found in dictyosomes and vesicles is observed between the cell membrane and wall in glutaraldehyde-formaldehyde-fixed tissue. At the electron-microscope level label in peripheral root cap cells incubated in [ 3 H]fucose for periods from 10 to 120 min was found primarily over dictyosomes and vesicles. In pulse-chase experiments label was chased from the diclyosomes and vesicles to the exterior of the cell in 20-30 min. Less than 19% of the label in pulse-chase experiments was associated with organelles other than dictyosomes vesicles. (orig.) [de

IMAZAPYR-RESISTANT MAIZE TECHNOLOGY ADOPTION FOR ...

African Journals Online (AJOL)

Prof. Adipala Ekwamu

decisions by protecting maize (Zea mays L.) crop in western Kenya from Striga. Key Words: Adopters, Zea ... Africa, efficient and profitable production of maize is severely constrained by ..... gap by understanding its source. African. Journal of ...

Growth performance and carcass characteristics of Tanzania Shorthorn Zebu cattle finished on molasses or maize grain with rice or maize by-products

DEFF Research Database (Denmark)

Asimwe, I.; Kimambo, A. E.; Laswai, G. H.

2015-01-01

Forty five steers (2.5–3.0 years of age and 200±5 (SEM) kg body weight) were allotted randomly into five diets to assess the effects of finishing Tanzania Shorthorn Zebu (TSZ) cattle in feedlot using diets based on either molasses or maize grain combined with maize or rice by-products. The diets...... were hay and concentrate mixtures of hominy feed with molasses (HFMO), rice polishing with molasses (RPMO), hominy feed with maize meal (HFMM), rice polishing with maize meal (RPMM) and a control of maize meal with molasses (MMMO). All concentrate mixtures contained cotton seed cake, mineral mixture.......35 for HFMO) than in maize grain based diets (6.94, 6.73 and 6.19 for RPMM, MMMO and HFMM, respectively). Energy intake was highest (P

Three-dimensional hydrogel cell culture systems for modeling neural tissue

Science.gov (United States)

Frampton, John

Two-dimensional (2-D) neural cell culture systems have served as physiological models for understanding the cellular and molecular events that underlie responses to physical and chemical stimuli, control sensory and motor function, and lead to the development of neurological diseases. However, the development of three-dimensional (3-D) cell culture systems will be essential for the advancement of experimental research in a variety of fields including tissue engineering, chemical transport and delivery, cell growth, and cell-cell communication. In 3-D cell culture, cells are provided with an environment similar to tissue, in which they are surrounded on all sides by other cells, structural molecules and adhesion ligands. Cells grown in 3-D culture systems display morphologies and functions more similar to those observed in vivo, and can be cultured in such a way as to recapitulate the structural organization and biological properties of tissue. This thesis describes a hydrogel-based culture system, capable of supporting the growth and function of several neural cell types in 3-D. Alginate hydrogels were characterized in terms of their biomechanical and biochemical properties and were functionalized by covalent attachment of whole proteins and peptide epitopes. Methods were developed for rapid cross-linking of alginate hydrogels, thus permitting the incorporation of cells into 3-D scaffolds without adversely affecting cell viability or function. A variety of neural cell types were tested including astrocytes, microglia, and neurons. Cells remained viable and functional for longer than two weeks in culture and displayed process outgrowth in 3-D. Cell constructs were created that varied in cell density, type and organization, providing experimental flexibility for studying cell interactions and behavior. In one set of experiments, 3-D glial-endothelial cell co-cultures were used to model blood-brain barrier (BBB) structure and function. This co-culture system was

A review on threat of gray leaf spot disease of maize in Asia

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Narayan Bahadur Dhami

2015-12-01

Full Text Available Biotic and biotic constraints are yield limiting factors in maize producing regions. Among these gray leaf spot is a yield limiting foliar disease of maize in high land regions of Asia. This review is done from related different national and international journals, thesis, books, research papers etc. The objectives of this review are to become familiar with genetics and inheritance, epidemiology, symptoms and disease management strategies etc. High relative humidity, temperature, minimum tillage and maize monoculture are important factors responsible for disease development. The sibling species of Cercospora zeae-maydis (Tehon and Daniels, 1925 Group I and Group II and Cercospora sorghai var. maydis (Chupp, 1954 are associated with this disease. Pathogens colonize in maize debris. Conidia are the source of inoculums for disease spread. Severe blighting of leaves reduces sugars, stalk lodging and causes premature death of plants resulting in yield losses of up to 100%. Disease management through cultural practices is provisional. The use of fungicides for emergencies is effective however; their prohibitive cost and detrimental effects on the environment are negative consequences. The inheritance of tolerance is quantitative with small additive effects. The introgression of resistant genes among the crosses of resistant germplasm enhances the resistance. The crosses of resistant and susceptible germplasm possess greater stability than the crosses of susceptible and resistant germplasm. The development of gray leaf spot tolerant populations through tolerance breeding principle is an economical and sustainable approach to manage the disease.

Cell-cycle distributions and radiation responses of Chinese hamster cells cultured continuously under hypoxic conditions

International Nuclear Information System (INIS)

Tokita, N.; Carpenter, S.G.; Raju, M.R.

1984-01-01

Cell-cycle distributions were measured by flow cytometry for Chinese hamster (CHO) cells cultured continuously under hypoxic conditions. DNA histograms showed an accumulation of cells in the early S phase followed by a traverse delay through the S phase, and a G 2 block. During hypoxic culturing, cell viability decreased rapidly to less than 0.1% at 120 h. Radiation responses for cells cultured under these conditions showed an extreme radioresistance at 72 h. Results suggest that hypoxia induces a condition similar to cell synchrony which itself changes the radioresistance of hypoxic cells. (author)

The initiation of lateral roots in the primary roots of maize (Zea mays L.) implies a reactivation of cell proliferation in a group of founder pericycle cells.

Science.gov (United States)

Alarcón, M Victoria; Lloret, Pedro G; Martín-Partido, Gervasio; Salguero, Julio

2016-03-15

The initiation of lateral roots (LRs) has generally been viewed as a reactivation of proliferative activity in pericycle cells that are committed to initiate primordia. However, it is also possible that pericycle founder cells that initiate LRs never cease proliferative activity but rather are displaced to the most distal root zones while undertaking successive stages of LR initiation. In this study, we tested these two alternative hypotheses by examining the incorporation of 5-bromo-2'-deoxyuridine (BrdU) into the DNA of meristematic root cells of Zea mays. According to the values for the length of the cell cycle and values for cell displacement along the maize root, our results strongly suggest that pericycle cells that initiate LR primordia ceased proliferative activity upon exiting the meristematic zone. This finding is supported by the existence of a root zone between 4 and 20mm from the root cap junction, in which neither mitotic cells nor labelled nuclei were observed in phloem pericycle cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

Engineering systems for the generation of patterned co-cultures for controlling cell-cell interactions.

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Kaji, Hirokazu; Camci-Unal, Gulden; Langer, Robert; Khademhosseini, Ali

2011-03-01

Inside the body, cells lie in direct contact or in close proximity to other cell types in a tightly controlled architecture that often regulates the resulting tissue function. Therefore, tissue engineering constructs that aim to reproduce the architecture and the geometry of tissues will benefit from methods of controlling cell-cell interactions with microscale resolution. We discuss the use of microfabrication technologies for generating patterned co-cultures. In addition, we categorize patterned co-culture systems by cell type and discuss the implications of regulating cell-cell interactions in the resulting biological function of the tissues. Patterned co-cultures are a useful tool for fabricating tissue engineered constructs and for studying cell-cell interactions in vitro, because they can be used to control the degree of homotypic and heterotypic cell-cell contact. In addition, this approach can be manipulated to elucidate important factors involved in cell-matrix interactions. Patterned co-culture strategies hold significant potential to develop biomimetic structures for tissue engineering. It is expected that they would create opportunities to develop artificial tissues in the future. This article is part of a Special Issue entitled Nanotechnologies - Emerging Applications in Biomedicine. 2010 Elsevier B.V. All rights reserved.

Studying mixing in Non-Newtonian blue maize flour suspensions using color analysis.

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Grissel Trujillo-de Santiago

Full Text Available BACKGROUND: Non-Newtonian fluids occur in many relevant flow and mixing scenarios at the lab and industrial scale. The addition of acid or basic solutions to a non-Newtonian fluid is not an infrequent operation, particularly in Biotechnology applications where the pH of Non-Newtonian culture broths is usually regulated using this strategy. METHODOLOGY AND FINDINGS: We conducted mixing experiments in agitated vessels using Non-Newtonian blue maize flour suspensions. Acid or basic pulses were injected to reveal mixing patterns and flow structures and to follow their time evolution. No foreign pH indicator was used as blue maize flours naturally contain anthocyanins that act as a native, wide spectrum, pH indicator. We describe a novel method to quantitate mixedness and mixing evolution through Dynamic Color Analysis (DCA in this system. Color readings corresponding to different times and locations within the mixing vessel were taken with a digital camera (or a colorimeter and translated to the CIELab scale of colors. We use distances in the Lab space, a 3D color space, between a particular mixing state and the final mixing point to characterize segregation/mixing in the system. CONCLUSION AND RELEVANCE: Blue maize suspensions represent an adequate and flexible model to study mixing (and fluid mechanics in general in Non-Newtonian suspensions using acid/base tracer injections. Simple strategies based on the evaluation of color distances in the CIELab space (or other scales such as HSB can be adapted to characterize mixedness and mixing evolution in experiments using blue maize suspensions.

Morphological and Immunohistochemical Characterization of Canine Osteosarcoma Spheroid Cell Cultures.

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Gebhard, C; Gabriel, C; Walter, I

2016-06-01

Spheroid cell culture emerges as powerful in vitro tool for experimental tumour research. In this study, we established a scaffold-free three-dimensional spheroid system built from canine osteosarcoma (OS) cells (D17). Spheroids (7, 14 and 19 days of cultivation) and monolayer cultures (2 and 7 days of cultivation) were evaluated and compared on light and electron microscopy. Monolayer and spheroid cultures were tested for vimentin, cytokeratin, alkaline phosphatase, osteocalcin and collagen I by means of immunohistochemistry. The spheroid cell culture exhibited a distinct network of collagen I in particular after 19-day cultivation, whereas in monolayer cultures, collagen I was arranged as a lamellar basal structure. Necrotic centres of large spheroids, as observed in 14- and 19-day cultures, were characterized by significant amounts of osteocalcin. Proliferative activity as determined by Ki-67 immunoreactivity showed an even distribution in two-dimensional cultures. In spheroids, proliferation was predominating in the peripheral areas. Metastasis-associated markers ezrin and S100A4 were shown to be continuously expressed in monolayer and spheroid cultures. We conclude that the scaffold-free spheroid system from canine OS cells has the ability to mimic the architecture of the in vivo tumour, in particular cell-cell and cell-matrix interactions. © 2015 The Authors. Anatomia, Histologia, Embryologia Published by Blackwell Verlag GmbH.

A microwell cell culture platform for the aggregation of pancreatic β-cells.

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Bernard, Abigail B; Lin, Chien-Chi; Anseth, Kristi S

2012-08-01

Cell-cell contact between pancreatic β-cells is important for maintaining survival and normal insulin secretion. Various techniques have been developed to promote cell-cell contact between β-cells, but a simple yet robust method that affords precise control over three-dimensional (3D) β-cell cluster size has not been demonstrated. To address this need, we developed a poly(ethylene glycol) (PEG) hydrogel microwell platform using photolithography. This microwell cell-culture platform promotes the formation of 3D β-cell aggregates of defined sizes from 25 to 210 μm in diameter. Using this platform, mouse insulinoma 6 (MIN6) β-cells formed aggregates with cell-cell adherin junctions. These naturally formed cell aggregates with controllable sizes can be removed from the microwells for macroencapsulation, implantation, or other biological assays. When removed and subsequently encapsulated in PEG hydrogels, the aggregated cell clusters demonstrated improved cellular viability (>90%) over 7 days in culture, while the β-cells encapsulated as single cells maintained only 20% viability. Aggregated MIN6 cells also exhibited more than fourfold higher insulin secretion in response to a glucose challenge compared with encapsulated single β-cells. Further, the cell aggregates stained positively for E-cadherin, indicative of the formation of cell junctions. Using this hydrogel microwell cell-culture method, viable and functional β-cell aggregates of specific sizes were created, providing a platform from which other biologically relevant questions may be answered.

CERES-Maize model-based simulation of climate change impacts on maize yields and potential adaptive measures in Heilongjiang Province, China.

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Lin, Yumei; Wu, Wenxiang; Ge, Quansheng

2015-11-01

Climate change would cause negative impacts on future agricultural production and food security. Adaptive measures should be taken to mitigate the adverse effects. The objectives of this study were to simulate the potential effects of climate change on maize yields in Heilongjiang Province and to evaluate two selected typical household-level autonomous adaptive measures (cultivar changes and planting time adjustments) for mitigating the risks of climate change based on the CERES-Maize model. The results showed that flowering duration and maturity duration of maize would be shortened in the future climate and thus maize yield would reduce by 11-46% during 2011-2099 relative to 1981-2010. Increased CO2 concentration would not benefit maize production significantly. However, substituting local cultivars with later-maturing ones and delaying the planting date could increase yields as the climate changes. The results provide insight regarding the likely impacts of climate change on maize yields and the efficacy of selected adaptive measures by presenting evidence-based implications and mitigation strategies for the potential negative impacts of future climate change. © 2014 Society of Chemical Industry.

Quantitative volumetric Raman imaging of three dimensional cell cultures

KAUST Repository

Kallepitis, Charalambos

2017-03-22

The ability to simultaneously image multiple biomolecules in biologically relevant three-dimensional (3D) cell culture environments would contribute greatly to the understanding of complex cellular mechanisms and cell–material interactions. Here, we present a computational framework for label-free quantitative volumetric Raman imaging (qVRI). We apply qVRI to a selection of biological systems: human pluripotent stem cells with their cardiac derivatives, monocytes and monocyte-derived macrophages in conventional cell culture systems and mesenchymal stem cells inside biomimetic hydrogels that supplied a 3D cell culture environment. We demonstrate visualization and quantification of fine details in cell shape, cytoplasm, nucleus, lipid bodies and cytoskeletal structures in 3D with unprecedented biomolecular specificity for vibrational microspectroscopy.

Cell division requirement for activation of murine leukemia virus in cell culture by irradiation

International Nuclear Information System (INIS)

Otten, J.A.; Quarles, J.M.; Tennant, R.W.

1976-01-01

Actively dividing cultures of AKR mouse cells were exposed to relatively low dose-rates of γ radiation and tested for activation of endogenous leukemia viruses. Efficient and reproducible induction of virus was obtained with actively dividing cells, but cultures deprived of serum to inhibit cell division before and during γ irradiation were not activated, even when medium with serum was added immediately after irradiation. These results show that cell division was required for virus induction but that a stable intermediate similar to the state induced by halogenated pyrimidines was not formed. In actively dividing AKR cell cultures, virus activation appeared to be proportional to the dose of γ radiation; the estimated frequency of activation was 1-8 x 10 - 5 per exposed cell and the efficiency of activation was approximately 0.012 inductions per cell per rad. Other normal primary and established mouse cell cultures tested were not activated by γ radiation. The requirement of cell division for radiation and chemical activation may reflect some common mechanism for initiation of virus expression

T cell resistance to activation by dendritic cells requires long-term culture in simulated microgravity

Science.gov (United States)

Bradley, Jillian H.; Stein, Rachel; Randolph, Brad; Molina, Emily; Arnold, Jennifer P.; Gregg, Randal K.

2017-11-01

Immune impairment mediated by microgravity threatens the success of space exploration requiring long-duration spaceflight. The cells of most concern, T lymphocytes, coordinate the host response against microbial and cancerous challenges leading to elimination and long-term protection. T cells are activated upon recognition of specific microbial peptides bound on the surface of antigen presenting cells, such as dendritic cells (DC). Subsequently, this engagement results in T cell proliferation and differentiation into effector T cells driven by autocrine interleukin-2 (IL-2) and other cytokines. Finally, the effector T cells acquire the weaponry needed to destroy microbial invaders and tumors. Studies conducted on T cells during spaceflight, or using Earth-based culture systems, have shown reduced production of cytokines, proliferation and effector functions as compared to controls. This may account for the cases of viral reactivation events and opportunistic infections associated with astronauts of numerous missions. This work has largely been based upon the outcome of T cell activation by stimulatory factors that target select T cell signaling pathways rather than the complex, signaling events related to the natural process of antigen presentation by DC. This study tested the response of an ovalbumin peptide-specific T cell line, OT-II TCH, to activation by DC when the T cells were cultured 24-120 h in a simulated microgravity (SMG) environment generated by a rotary cell culture system. Following 72 h culture of T cells in SMG (SMG-T) or control static (Static-T) conditions, IL-2 production by the T cells was reduced in SMG-T cells compared to Static-T cells upon stimulation by phorbol 12-myristate 13-acetate (PMA) and ionomycin. However, when the SMG-T cells were stimulated with DC and peptide, IL-2 was significantly increased compared to Static-T cells. Such enhanced IL-2 production by SMG-T cells peaked at 72 h SMG culture time and decreased thereafter. When

Tumor necrosis factor (cachetin) decreases adipose cell differentiation in primary cell culture

International Nuclear Information System (INIS)

Martin, R.J.; Jones, D.D.; Jewell, D.E.; Hausman, G.J.

1986-01-01

Cachetin has been shown to effect gene product expression in the established adipose cell line 3T3-L1. Expression of messenger RNA for lipoprotein lipase is suppressed in cultured adipocytes. The purpose of this study was to determine the effect of Cachetin on adipose cell differentiation in primary cell culture. Stromalvascular cells obtained from the inguinal fat pad of 4-5 week old Sprague-Dawley rats were grown in culture for two weeks. During the proliferative growth phase all cells were grown on the same medium and labelled with 3 H-thymidine. Cachetin treatment (10 -6 to 10 -10 M) was initiated on day 5, the initial phase of preadipocyte differentiation. Adipocytes and stromal cells were separated using density gradient, and 3 H-thymidine was determined for both cell types. Thymidine incorporation into adipose cells was decreased maximally (∼ 50%) at 10 -10 M. Stromalvascular cells were not influenced at any of the doses tested. Adipose cell lipid content as indicated by oil red-O staining was decreased by Cachetin. Esterase staining by adipose cells treated with Cachetin was increased indicating an increase in intracellular lipase. These studies show that Cachetin has specific effects on primary adipose cell differentiation

Feeding Frequency Affects Cultured Rat Pituitary Cells in Low Gravity

Science.gov (United States)

Hymer, W. C.; Grindeland, R. E.; Salada, T.; Cenci, R.; Krishnan, K.; Mukai, C.; Nagaoka, S.

1996-01-01

In this report, we describe the results of a rat pituitary cell culture experiment done on STS-65 in which the effect of cell feeding on the release of the six anterior pituitary hormones was studied. We found complex microgravity related interactions between the frequency of cell feeding and the quantity and quality (i.e. biological activity) of some of the six hormones released in flight. Analyses of growth hormone (GH) released from cells into culture media on different mission days using gel filtration and ion exchange chromatography yielded qualitatively similar results between ground and flight samples. Lack of cell feeding resulted in extensive cell clumping in flight (but not ground) cultures. Vigorous fibroblast growth occurred in both ground and flight cultures fed 4 times. These results are interpreted within the context of autocrine and or paracrine feedback interactions. Finally the payload specialist successfully prepared a fresh trypsin solution in microgravity, detached the cells from their surface and reinserted them back into the culture chamber. These cells reattached and continued to release hormone in microgravity. In summary, this experiment shows that pituitary cells are microgravity sensitive and that coupled operations routinely associated with laboratory cel1 culture can also be accomplished in low gravity.

Mixture design of rice flour, maize starch and wheat starch for optimization of gluten free bread quality.

Science.gov (United States)

Mancebo, Camino M; Merino, Cristina; Martínez, Mario M; Gómez, Manuel

2015-10-01

Gluten-free bread production requires gluten-free flours or starches. Rice flour and maize starch are two of the most commonly used raw materials. Over recent years, gluten-free wheat starch is available on the market. The aim of this research was to optimize mixtures of rice flour, maize starch and wheat starch using an experimental mixture design. For this purpose, dough rheology and its fermentation behaviour were studied. Quality bread parameters such as specific volume, texture, cell structure, colour and acceptability were also analysed. Generally, starch incorporation reduced G* and increased the bread specific volume and cell density, but the breads obtained were paler than the rice flour breads. Comparing the starches, wheat starch breads had better overall acceptability and had a greater volume than maize-starch bread. The highest value for sensorial acceptability corresponded to the bread produced with a mixture of rice flour (59 g/100 g) and wheat starch (41 g/100 g).

Meiotic transmission of an in vitro-assembled autonomous maize minichromosome.

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Shawn R Carlson

2007-10-01

Full Text Available Autonomous chromosomes are generated in yeast (yeast artificial chromosomes and human fibrosarcoma cells (human artificial chromosomes by introducing purified DNA fragments that nucleate a kinetochore, replicate, and segregate to daughter cells. These autonomous minichromosomes are convenient for manipulating and delivering DNA segments containing multiple genes. In contrast, commercial production of transgenic crops relies on methods that integrate one or a few genes into host chromosomes; extensive screening to identify insertions with the desired expression level, copy number, structure, and genomic location; and long breeding programs to produce varieties that carry multiple transgenes. As a step toward improving transgenic crop production, we report the development of autonomous maize minichromosomes (MMCs. We constructed circular MMCs by combining DsRed and nptII marker genes with 7-190 kb of genomic maize DNA fragments containing satellites, retroelements, and/or other repeats commonly found in centromeres and using particle bombardment to deliver these constructs into embryogenic maize tissue. We selected transformed cells, regenerated plants, and propagated their progeny for multiple generations in the absence of selection. Fluorescent in situ hybridization and segregation analysis demonstrated that autonomous MMCs can be mitotically and meiotically maintained. The MMC described here showed meiotic segregation ratios approaching Mendelian inheritance: 93% transmission as a disome (100% expected, 39% transmission as a monosome crossed to wild type (50% expected, and 59% transmission in self crosses (75% expected. The fluorescent DsRed reporter gene on the MMC was expressed through four generations, and Southern blot analysis indicated the encoded genes were intact. This novel approach for plant transformation can facilitate crop biotechnology by (i combining several trait genes on a single DNA fragment, (ii arranging genes in a defined

Characterization of rhizobacteria associated to maize crop in IAA, siderophores and salicylic acid metabolite production

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Annia Hernández

2004-01-01

Full Text Available It has been demonstrated that rhizobacteria are able to produce metabolites having agricultural interest, including salicylic acid, the siderophores and phytohormones. Indol acetic acid (IAA is the most well-known and studied auxin, playing a governing role in culture growth. The object of this work was to characterise rhizobacteria associated with the maize crop in terms of producing IAA, siderophores and salicylic acid metabolites. Burkholderia cepacia and Pseudomonas fluorescens strains previously isolated from maize Francisco variety rhizosphere were used. Colorimetric and chromatographic techniques for detecting these metabolites were studied; multi-variable analysis of hierarchic conglomerate and complete ligament were used for selecting the best strains for producing metabolites of interest. These results demonstrated that all rhizobacteria strains studied produced IAA, siderophores and salicylic acid metabolites. Burkholderia cepacia MBf21, MBp1, MBp2, MBf22, MBp3, MBf20, MBf 15 and Pseudomonas fluorescens MPp4strains have presented the greatest production of these metabolites, showing that these strains could be used in promoting vegetal growth in economically important cultures. Key words: Pseudomonas fluorescens, Burkholderia cepacia, IAA, siderophore, salicylic acid.

Transcriptional analyses of natural leaf senescence in maize.

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Wei Yang Zhang

Full Text Available Leaf senescence is an important biological process that contributes to grain yield in crops. To study the molecular mechanisms underlying natural leaf senescence, we harvested three different developmental ear leaves of maize, mature leaves (ML, early senescent leaves (ESL, and later senescent leaves (LSL, and analyzed transcriptional changes using RNA-sequencing. Three sets of data, ESL vs. ML, LSL vs. ML, and LSL vs. ESL, were compared, respectively. In total, 4,552 genes were identified as differentially expressed. Functional classification placed these genes into 18 categories including protein metabolism, transporters, and signal transduction. At the early stage of leaf senescence, genes involved in aromatic amino acids (AAAs biosynthetic process and transport, cellular polysaccharide biosynthetic process, and the cell wall macromolecule catabolic process, were up-regulated. Whereas, genes involved in amino acid metabolism, transport, apoptosis, and response to stimulus were up-regulated at the late stage of leaf senescence. Further analyses reveals that the transport-related genes at the early stage of leaf senescence potentially take part in enzyme and amino acid transport and the genes upregulated at the late stage are involved in sugar transport, indicating nutrient recycling mainly takes place at the late stage of leaf senescence. Comparison between the data of natural leaf senescence in this study and previously reported data for Arabidopsis implies that the mechanisms of leaf senescence in maize are basically similar to those in Arabidopsis. A comparison of natural and induced leaf senescence in maize was performed. Athough many basic biological processes involved in senescence occur in both types of leaf senescence, 78.07% of differentially expressed genes in natural leaf senescence were not identifiable in induced leaf senescence, suggesting that differences in gene regulatory network may exist between these two leaf senescence

Characterization of primary human mammary epithelial cells isolated and propagated by conditional reprogrammed cell culture.

Science.gov (United States)

Jin, Liting; Qu, Ying; Gomez, Liliana J; Chung, Stacey; Han, Bingchen; Gao, Bowen; Yue, Yong; Gong, Yiping; Liu, Xuefeng; Amersi, Farin; Dang, Catherine; Giuliano, Armando E; Cui, Xiaojiang

2018-02-20

Conditional reprogramming methods allow for the inexhaustible in vitro proliferation of primary epithelial cells from human tissue specimens. This methodology has the potential to enhance the utility of primary cell culture as a model for mammary gland research. However, few studies have systematically characterized this method in generating in vitro normal human mammary epithelial cell models. We show that cells derived from fresh normal breast tissues can be propagated and exhibit heterogeneous morphologic features. The cultures are composed of CK18, desmoglein 3, and CK19-positive luminal cells and vimentin, p63, and CK14-positive myoepithelial cells, suggesting the maintenance of in vivo heterogeneity. In addition, the cultures contain subpopulations with different CD49f and EpCAM expression profiles. When grown in 3D conditions, cells self-organize into distinct structures that express either luminal or basal cell markers. Among these structures, CK8-positive cells enclosing a lumen are capable of differentiation into milk-producing cells in the presence of lactogenic stimulus. Furthermore, our short-term cultures retain the expression of ERα, as well as its ability to respond to estrogen stimulation. We have investigated conditionally reprogrammed normal epithelial cells in terms of cell type heterogeneity, cellular marker expression, and structural arrangement in two-dimensional (2D) and three-dimensional (3D) systems. The conditional reprogramming methodology allows generation of a heterogeneous culture from normal human mammary tissue in vitro . We believe that this cell culture model will provide a valuable tool to study mammary cell function and malignant transformation.

quixotic coupling between irrigation system and maize-cowpea

African Journals Online (AJOL)

ACSS

number row-1 and maize grain yield, respectively. The ridge ... Key Words: Furrow irrigation, water use efficiency, Zea mays. RÉSUMÉ ... important in arid and semi-arid regions, with ... as maize) canopy is not able to intercept all the solar radiation during the growth period. ... Intercropping maize and legumes considerably ...

Antitumor Activity of Rat Mesenchymal Stem Cells during Direct or Indirect Co-Culturing with C6 Glioma Cells.

Science.gov (United States)

Gabashvili, A N; Baklaushev, V P; Grinenko, N F; Mel'nikov, P A; Cherepanov, S A; Levinsky, A B; Chehonin, V P

2016-02-01

The tumor-suppressive effect of rat mesenchymal stem cells against low-differentiated rat C6 glioma cells during their direct and indirect co-culturing and during culturing of C6 glioma cells in the medium conditioned by mesenchymal stem cells was studied in an in vitro experiment. The most pronounced antitumor activity of mesenchymal stem cells was observed during direct co-culturing with C6 glioma cells. The number of live C6 glioma cells during indirect co-culturing and during culturing in conditioned medium was slightly higher than during direct co-culturing, but significantly differed from the control (C6 glioma cells cultured in medium conditioned by C6 glioma cells). The cytotoxic effect of medium conditioned by mesenchymal stem cells was not related to medium depletion by glioma cells during their growth. The medium conditioned by other "non-stem" cells (rat astrocytes and fibroblasts) produced no tumor-suppressive effect. Rat mesenchymal stem cells, similar to rat C6 glioma cells express connexin 43, the main astroglial gap junction protein. During co-culturing, mesenchymal stem cells and glioma C6 cells formed functionally active gap junctions. Gap junction blockade with connexon inhibitor carbenoxolone attenuated the antitumor effect observed during direct co-culturing of C6 glioma cells and mesenchymal stem cells to the level produced by conditioned medium. Cell-cell signaling mediated by gap junctions can be a mechanism of the tumor-suppressive effect of mesenchymal stem cells against C6 glioma cells. This phenomenon can be used for the development of new methods of cell therapy for high-grade malignant gliomas.

Advances in tissue engineering through stem cell-based co-culture.

Science.gov (United States)

Paschos, Nikolaos K; Brown, Wendy E; Eswaramoorthy, Rajalakshmanan; Hu, Jerry C; Athanasiou, Kyriacos A

2015-05-01

Stem cells are the future in tissue engineering and regeneration. In a co-culture, stem cells not only provide a target cell source with multipotent differentiation capacity, but can also act as assisting cells that promote tissue homeostasis, metabolism, growth and repair. Their incorporation into co-culture systems seems to be important in the creation of complex tissues or organs. In this review, critical aspects of stem cell use in co-culture systems are discussed. Direct and indirect co-culture methodologies used in tissue engineering are described, along with various characteristics of cellular interactions in these systems. Direct cell-cell contact, cell-extracellular matrix interaction and signalling via soluble factors are presented. The advantages of stem cell co-culture strategies and their applications in tissue engineering and regenerative medicine are portrayed through specific examples for several tissues, including orthopaedic soft tissues, bone, heart, vasculature, lung, kidney, liver and nerve. A concise review of the progress and the lessons learned are provided, with a focus on recent developments and their implications. It is hoped that knowledge developed from one tissue can be translated to other tissues. Finally, we address challenges in tissue engineering and regenerative medicine that can potentially be overcome via employing strategies for stem cell co-culture use. Copyright © 2014 John Wiley & Sons, Ltd.

Systemic virus-induced gene silencing allows functional characterization of maize genes during biotrophic interaction with Ustilago maydis.

Science.gov (United States)

van der Linde, Karina; Kastner, Christine; Kumlehn, Jochen; Kahmann, Regine; Doehlemann, Gunther

2011-01-01

Infection of maize (Zea mays) plants with the corn smut fungus Ustilago maydis leads to the formation of large tumors on the stem, leaves and inflorescences. In this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed massive and stage-specific changes in host gene expression during disease progression. To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a virus-induced gene silencing (VIGS) system based on the brome mosaic virus (BMV) for maize. Conditions were established that allowed successful U. maydis infection of BMV-preinfected maize plants. This set-up enabled quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (qRT-PCR)-based readout. In proof-of-principle experiments, an U. maydis-induced terpene synthase was shown to negatively regulate disease development while a protein involved in cell death inhibition was required for full virulence of U. maydis. The results suggest that this system is a versatile tool for the rapid identification of maize genes that determine compatibility with U. maydis. © (2010) Max Planck Society. Journal compilation © New Phytologist Trust (2010).

Stimulation of DNA synthesis in cultured rat alveolar type II cells

International Nuclear Information System (INIS)

Leslie, C.C.; McCormick-Shannon, K.; Robinson, P.C.; Mason, R.J.

1985-01-01

Restoration of the alveolar epithelium after injury is thought to be dependent on the proliferation of alveolar type II cells. To understand the factors that may be involved in promoting type II cell proliferation in vivo, we determined the effect of potential mitogens and culture substrata on DNA synthesis in rat alveolar type II cells in primary culture. Type II cells cultured in basal medium containing 10% fetal bovine serum (FBS) exhibited essentially no DNA synthesis. Factors that stimulated 3 H-thymidine incorporation included cholera toxin, epidermal growth factor, and rat serum. The greatest degree of stimulation was achieved by plating type II cells on an extracellular matrix prepared from bovine corneal endothelial cells and then by culturing the pneumocytes in medium containing rat serum, cholera toxin, insulin, and epidermal growth factor. Under conditions of stimulation of 3 H-thymidine incorporation there was an increased DNA content per culture dish but no increase in cell number. The ability of various culture conditions to promote DNA synthesis in type II cells was verified by autoradiography. Type II cells were identified by the presence of cytoplasmic inclusions, which were visualized by tannic acid staining before autoradiography. These results demonstrate the importance of soluble factors and culture substratum in stimulating DNA synthesis in rat alveolar type II cells in primary culture

Propanol in maize silage at Danish dairy farms

DEFF Research Database (Denmark)

Raun, Birgitte Marie Løvendahl; Kristensen, Niels Bastian

2010-01-01

The objective of the present study was to investigate the prevalence maize silage containing propanol, the seasonal variation in propanol content of maize silage, and correlations between propanol and other fermentation products in maize silage collected from 20 randomly selected Danish dairy farms...... farms, the maize silage had ≥5 g propanol/kg DM. The present study indicates that dairy cows in Denmark are commonly exposed to propanol and that approximately 20% of the dairy cows will have an intake in the range of 75-100 g propanol/d under common feeding conditions....

Water transfer in an alfalfa/maize association

International Nuclear Information System (INIS)

Corak, S.J.; Blevins, D.G.; Pallardy, S.G.

1987-01-01

The authors investigated the possibility of interspecific water transfer in an alfalfa (Medicago sativa L.) and maize (Zea mays L.) association. An alfalfa plant was grown through two vertically stacked plastic tubes. A 5 centimeter air gap between tubes was bridged by alfalfa roots. Five-week old maize plants with roots confined to the top tube were not watered, while associated alfalfa roots had free access to water in the bottom tube (the -/+ treatment). Additional treatments included: top and bottom tubes watered (+/+), top and bottom tubes droughted (-/-), and top tube droughted after removal of alfalfa root bridges and routine removal of alfalfa tillers (-*). Predawn leaf water potential of maize in the -/+ treatment fell to -1.5 megapascals 13 days after the start of drought; thereafter, predawn and midday potentials were maintained near -1.9 megapascals. Leaf water potentials of maize in the -/- and -* treatments declined steadily; all plants in these treatments were completely desiccated before day 50. High levels of tritium activity were detected in water extracted from both alfalfa and maize leaves after 3 H 2 O was injected into the bottom -/+ tube at day 70 or later. Maize in the -/+ treatment was able to survive an otherwise lethal period of drought by utilizing water lost by alfalfa roots

Sub-Saharan African maize-based foods

NARCIS (Netherlands)

Ekpa, Onu; Palacios-Rojas, Natalia; Kruseman, Gideon; Fogliano, Vincenzo; Linnemann, Anita R.

2018-01-01

The demand for maize in Sub-Saharan Africa will triple by 2050 due to rapid population growth, while challenges from climate change will threaten agricultural productivity. Most maize breeding programmes have focused on improving agronomic properties and have paid relatively little attention to

Lack of detectable allergenicity in genetically modified maize containing "Cry" proteins as compared to native maize based on in silico & in vitro analysis.

Directory of Open Access Journals (Sweden)

Chandni Mathur

Full Text Available Genetically modified, (GM crops with potential allergens must be evaluated for safety and endogenous IgE binding pattern compared to native variety, prior to market release.To compare endogenous IgE binding proteins of three GM maize seeds containing Cry 1Ab,1Ac,1C transgenic proteins with non GM maize.An integrated approach of in silico & in vitro methods was employed. Cry proteins were tested for presence of allergen sequence by FASTA in allergen databases. Biochemical assays for maize extracts were performed. Specific IgE (sIgE and Immunoblot using food sensitized patients sera (n = 39 to non GM and GM maize antigens was performed.In silico approaches, confirmed for non sequence similarity of stated transgenic proteins in allergen databases. An insignificant (p> 0.05 variation in protein content between GM and non GM maize was observed. Simulated Gastric Fluid (SGF revealed reduced number of stable protein fractions in GM then non GM maize which might be due to shift of constituent protein expression. Specific IgE values from patients showed insignificant difference in non GM and GM maize extracts. Five maize sensitized cases, recognized same 7 protein fractions of 88-28 kD as IgE bindng in both GM and non-GM maize, signifying absence of variation. Four of the reported IgE binding proteins were also found to be stable by SGF.Cry proteins did not indicate any significant similarity of >35% in allergen databases. Immunoassays also did not identify appreciable differences in endogenous IgE binding in GM and non GM maize.

Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective

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Olga Pechanova

2015-11-01

Full Text Available Maize (Zea mays L. is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus.

Maize-Pathogen Interactions: An Ongoing Combat from a Proteomics Perspective.

Science.gov (United States)

Pechanova, Olga; Pechan, Tibor

2015-11-30

Maize (Zea mays L.) is a host to numerous pathogenic species that impose serious diseases to its ear and foliage, negatively affecting the yield and the quality of the maize crop. A considerable amount of research has been carried out to elucidate mechanisms of maize-pathogen interactions with a major goal to identify defense-associated proteins. In this review, we summarize interactions of maize with its agriculturally important pathogens that were assessed at the proteome level. Employing differential analyses, such as the comparison of pathogen-resistant and susceptible maize varieties, as well as changes in maize proteomes after pathogen challenge, numerous proteins were identified as possible candidates in maize resistance. We describe findings of various research groups that used mainly mass spectrometry-based, high through-put proteomic tools to investigate maize interactions with fungal pathogens Aspergillus flavus, Fusarium spp., and Curvularia lunata, and viral agents Rice Black-streaked Dwarf Virus and Sugarcane Mosaic Virus.

EXPLANTATION OF MESANGIAL CELL HILLOCKS - A METHOD FOR OBTAINING HUMAN MESANGIAL CELLS IN CULTURE

NARCIS (Netherlands)

MULLER, EW; KIM, Y; MICHAEL, AF; VERNIER, RL; VANDERHEM, GK; VANDERWOUDE, FJ

A simple method is presented for selective cell culture of human mesangial cells using explanatation of mesangial cell hillocks. Glomeruli which had been incubated with collagenase were explanted on plastic tissue culture flasks. Three to 6 weeks after explantation, a rapidly growing multilayer of

Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells in irradiated bone marrow cell culture in vitro

International Nuclear Information System (INIS)

Fujitake, Hideki; Okamoto, Yuruko; Okubo, Hiroshi; Miyanomae, Takeshi; Kumagai, Keiko; Mori, K.J.

1981-01-01

Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells after irradiation were studied in the long-term culture of mouse bone marrow cells in vitro. No difference was observed in the survival of the stem cells among cultures in which 0 - 10 7 cells were re-inoculated on the adherent cell colonies in the culture flask. Stem cells showed a significant proliferation within 1 week and the number of the stem cells exceeded the control in 3 weeks after irradiation in the cultures with less than 10 6 re-inoculated cells per flask. In contrast, there was a considerable delay in the onset of stem cell proliferation after irradiation in the culture with 10 7 cells per flask. Based on these results, a possibility that a stimulator of stem cell proliferation, released from irradiated stromal cells, is cancelled by an inhibitory factor produced by irradiated or unirradiated haemopoietic cells is postulated. (author)

Differential resistance reaction of maize genotypes to maize stem borer (Chilo partellus Swinhoe at Chitwan, Nepal

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Ghanashyam Bhandari

2016-12-01

Full Text Available Maize stem borer (MSB, Chilo partellus Swinhoe, Lepidoptera: Pyralidae is one of the most important insect pest of maize in Nepal. Host plant resistance is the cost-effective, ecologically sound and stable approach to reduce damage by stem borers. Forty four maize genotypes were screened for resistance to maize stem borer at the research field of National Maize Research Program, Rampur during spring seasons (March to June of two consecutive years 2013 and 2014. The maize genotypes were evaluated in randomized complete block design with three replications and data were collected on foliar damage rating, tunnel length and number of exit holes made by the borer. The foliar damage and tunnel length damage were significant for genotypes for both the years. The exit holes were not significant in 2013 but significant in 2014 ranging from 2-6 scale. The foliar rating ranged from 2 to 5.5 in 2013 and 1.1 to 4.5 in 2014 on a 1-9 rating scale. The highly resistant genotypes (10 cm scale. The least susceptible genotypes (<5 cm were RampurSO3F8, RampurSO3FQ02 and RampurS10F18. The genotypes having least exit holes (2.0 in 2014 were RampurSO3F8, RampurSO3FQ02, RampurS10F18. Thus less damage parameters were observed in R-POP-2, RML-5/RML-8, RampurSO3F8, RampurSO3FQ02 and RampurS10F18 and therefore they can be used as parents or as sources of resistance in breeding program.

Transcriptomic and anatomical complexity of primary, seminal, and crown roots highlight root type-specific functional diversity in maize (Zea mays L.).

Science.gov (United States)

Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank

2016-02-01

Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

21 CFR 876.5885 - Tissue culture media for human ex vivo tissue and cell culture processing applications.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tissue culture media for human ex vivo tissue and cell culture processing applications. 876.5885 Section 876.5885 Food and Drugs FOOD AND DRUG... DEVICES Therapeutic Devices § 876.5885 Tissue culture media for human ex vivo tissue and cell culture...

Retinal pigment epithelium culture;a potential source of retinal stem cells.

Science.gov (United States)

Akrami, Hassan; Soheili, Zahra-Soheila; Khalooghi, Keynoush; Ahmadieh, Hamid; Rezaie-Kanavi, Mojgan; Samiei, Shahram; Davari, Malihe; Ghaderi, Shima; Sanie-Jahromi, Fatemeh

2009-07-01

To establish human retinal pigment epithelial (RPE) cell culture as a source for cell replacement therapy in ocular diseases. Human cadaver globes were used to isolate RPE cells. Each globe was cut into several pieces of a few millimeters in size. After removing the sclera and choroid, remaining tissues were washed in phosphate buffer saline and RPE cells were isolated using dispase enzyme solution and cultured in Dulbecco's Modified Eagle's Medium: Nutrient Mixture F-12 supplemented with 10% fetal calf serum. Primary cultures of RPE cells were established and spheroid colonies related to progenitor/stem cells developed in a number of cultures. The colonies included purely pigmented or mixed pigmented and non-pigmented cells. After multiple cellular passages, several types of photoreceptors and neural-like cells were detected morphologically. Cellular plasticity in RPE cell cultures revealed promising results in terms of generation of stem/progenitor cells from human RPE cells. Whether the spheroids and neural-like retinal cells were directly derived from retinal stem cells or offspring of trans-differentiating or de-differentiating RPE cells remains to be answered.

Enhanced infectivity of bluetongue virus in cell culture by centrifugation.

OpenAIRE

Sundin, D R; Mecham, J O

1989-01-01

The effects of centrifugation of the infection of cell culture with bluetongue virus (BTV) were investigated. Baby hamster kidney cells were infected with BTV with or without centrifugation. Viral antigen was detected by immunofluorescence at 24 h in both centrifuged and noncentrifuged cultures. However, after 24 h of infection, the production of PFU in centrifuged cell cultures was 10- to 20-fold greater than that seen in cultures not centrifuged. In addition, centrifugation enhanced the dir...

Fungal Diversity of Maize (Zea Mays L. Grains

Directory of Open Access Journals (Sweden)

Gulbis Kaspars

2016-06-01

Full Text Available Maize is becoming more and more important crop for dairy farming as forage and as substrate for biogas production. The mycotoxin producing fungi can spoil feed, reduce cattle productivity and cause health problems. The aim of this research was to study the mycoflora of maize grains in order to clarify the fungal composition and verify the presence of potential mycotoxin producing fungi. The grain samples were collected from different maize hybrid performance trial in Research and Study farm “Vecauce” of Latvia University of Agriculture in 2014. The fungi from 14 genera were isolated from surface sterilized grains. The most abundant were Alternaria, Fusarium and Penicillium spp. Mycotoxin producing fungi are present in maize grain mycoflora, and there is a risk that maize production can contain mycotoxins.

Enrichment of skin-derived neural precursor cells from dermal cell populations by altering culture conditions.

Science.gov (United States)

Bayati, Vahid; Gazor, Rohoullah; Nejatbakhsh, Reza; Negad Dehbashi, Fereshteh

2016-01-01

As stem cells play a critical role in tissue repair, their manipulation for being applied in regenerative medicine is of great importance. Skin-derived precursors (SKPs) may be good candidates for use in cell-based therapy as the only neural stem cells which can be isolated from an accessible tissue, skin. Herein, we presented a simple protocol to enrich neural SKPs by monolayer adherent cultivation to prove the efficacy of this method. To enrich neural SKPs from dermal cell populations, we have found that a monolayer adherent cultivation helps to increase the numbers of neural precursor cells. Indeed, we have cultured dermal cells as monolayer under serum-supplemented (control) and serum-supplemented culture, followed by serum free cultivation (test) and compared. Finally, protein markers of SKPs were assessed and compared in both experimental groups and differentiation potential was evaluated in enriched culture. The cells of enriched culture concurrently expressed fibronectin, vimentin and nestin, an intermediate filament protein expressed in neural and skeletal muscle precursors as compared to control culture. In addition, they possessed a multipotential capacity to differentiate into neurogenic, glial, adipogenic, osteogenic and skeletal myogenic cell lineages. It was concluded that serum-free adherent culture reinforced by growth factors have been shown to be effective on proliferation of skin-derived neural precursor cells (skin-NPCs) and drive their selective and rapid expansion.

T cell resistance to activation by dendritic cells requires long-term culture in simulated microgravity.

Science.gov (United States)

Bradley, Jillian H; Stein, Rachel; Randolph, Brad; Molina, Emily; Arnold, Jennifer P; Gregg, Randal K

2017-11-01

Immune impairment mediated by microgravity threatens the success of space exploration requiring long-duration spaceflight. The cells of most concern, T lymphocytes, coordinate the host response against microbial and cancerous challenges leading to elimination and long-term protection. T cells are activated upon recognition of specific microbial peptides bound on the surface of antigen presenting cells, such as dendritic cells (DC). Subsequently, this engagement results in T cell proliferation and differentiation into effector T cells driven by autocrine interleukin-2 (IL-2) and other cytokines. Finally, the effector T cells acquire the weaponry needed to destroy microbial invaders and tumors. Studies conducted on T cells during spaceflight, or using Earth-based culture systems, have shown reduced production of cytokines, proliferation and effector functions as compared to controls. This may account for the cases of viral reactivation events and opportunistic infections associated with astronauts of numerous missions. This work has largely been based upon the outcome of T cell activation by stimulatory factors that target select T cell signaling pathways rather than the complex, signaling events related to the natural process of antigen presentation by DC. This study tested the response of an ovalbumin peptide-specific T cell line, OT-II TCH, to activation by DC when the T cells were cultured 24-120 h in a simulated microgravity (SMG) environment generated by a rotary cell culture system. Following 72 h culture of T cells in SMG (SMG-T) or control static (Static-T) conditions, IL-2 production by the T cells was reduced in SMG-T cells compared to Static-T cells upon stimulation by phorbol 12-myristate 13-acetate (PMA) and ionomycin. However, when the SMG-T cells were stimulated with DC and peptide, IL-2 was significantly increased compared to Static-T cells. Such enhanced IL-2 production by SMG-T cells peaked at 72 h SMG culture time and decreased thereafter

Maize Bioactive Peptides against Cancer

Science.gov (United States)

Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

2017-06-01

Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

Interaction effect on nitrogen and sulfur on growth and nutrient uptake by maize

International Nuclear Information System (INIS)

Jaggi, R.C.; Aulakh, M.S.; Dev, G.

1977-01-01

A pot culture experiment was conducted in the greenhouse on an arid brown loamy sand deficient in both available N and S with maize (Ganga-5) as the test corp. Three levels of N (0, 30, 60 ppm) as NH 4 Cl in factorial combination with three levels of S (0, 10, 20 ppm) as Na 2 35 SO 4 were replicated thrice. Application of N upto 60 ppm S significantly increased dry matter yield and uptake of N and S by maize (stem + levels) and their combined application showed sinergistic effect for both yield and uptake of these nutrients. Maximum yield of dry matter and uptake of the nutrients were obtained with the application of 60 ppm N and 20 ppm S. The radioassay data corroborated the beneficial effect of N on the efficiency of applied S. (author)

Identification of a population of cells with hematopoietic stem cell properties in mouse aorta-gonad-mesonephros cultures

International Nuclear Information System (INIS)

Nobuhisa, Ikuo; Ohtsu, Naoki; Okada, Seiji; Nakagata, Naomi; Taga, Tetsuya

2007-01-01

The aorta-gonad-mesonephros (AGM) region is a primary source of definitive hematopoietic cells in the midgestation mouse embryo. In cultures of dispersed AGM regions, adherent cells containing endothelial cells are observed first, and then non-adherent hematopoietic cells are produced. Here we report on the characterization of hematopoietic cells that emerge in the AGM culture. Based on the expression profiles of CD45 and c-Kit, we defined three cell populations: CD45 low c-Kit + cells that had the ability to form hematopoietic cell colonies in methylcellulose media and in co-cultures with stromal cells; CD45 low c-Kit - cells that showed a granulocyte morphology; CD45 high c-Kit low/- that exhibited a macrophage morphology. In co-cultures of OP9 stromal cells and freshly prepared AGM cultures, CD45 low c-Kit + cells from the AGM culture had the abilities to reproduce CD45 low c-Kit + cells and differentiate into CD45 low c-Kit - and CD45 high c-Kit low/- cells, whereas CD45 low c-Kit - and CD45 high c-Kit low/- did not produce CD45 low c-Kit + cells. Furthermore, CD45 low c-Kit + cells displayed a long-term repopulating activity in adult hematopoietic tissue when transplanted into the liver of irradiated newborn mice. These results indicate that CD45 low c-Kit + cells from the AGM culture have the potential to reconstitute multi-lineage hematopoietic cells

Cell fiber-based three-dimensional culture system for highly efficient expansion of human induced pluripotent stem cells.

Science.gov (United States)

Ikeda, Kazuhiro; Nagata, Shogo; Okitsu, Teru; Takeuchi, Shoji

2017-06-06

Human pluripotent stem cells are a potentially powerful cellular resource for application in regenerative medicine. Because such applications require large numbers of human pluripotent stem cell-derived cells, a scalable culture system of human pluripotent stem cell needs to be developed. Several suspension culture systems for human pluripotent stem cell expansion exist; however, it is difficult to control the thickness of cell aggregations in these systems, leading to increased cell death likely caused by limited diffusion of gases and nutrients into the aggregations. Here, we describe a scalable culture system using the cell fiber technology for the expansion of human induced pluripotent stem (iPS) cells. The cells were encapsulated and cultured within the core region of core-shell hydrogel microfibers, resulting in the formation of rod-shaped or fiber-shaped cell aggregations with sustained thickness and high viability. By encapsulating the cells with type I collagen, we demonstrated a long-term culture of the cells by serial passaging at a high expansion rate (14-fold in four days) while retaining its pluripotency. Therefore, our culture system could be used for large-scale expansion of human pluripotent stem cells for use in regenerative medicine.

Cystine uptake by cultured cells originating from dog proximal tubule segments

International Nuclear Information System (INIS)

States, B.; Reynolds, R.; Lee, J.; Segal, S.

1990-01-01

Large numbers of kidney epithelial cells were cultured successfully from isolated dog proximal tubule segments. Cells in primary culture and in first passage retained the cystine-dibasic amino acid co-transporter system which is found in vivo and in freshly isolated proximal tubule segments. In contrast to other cultured cells, the cystine-glutamate anti-porter was absent in primary cultures. However, this anti-porter system seemed to be developing in cells in first passage. The intracellular ratio of cysteine:reduced glutathione (CSH:GSH) was maintained at 1:36 in both primary cultures and in low passage cells. Incubation of cells in primary culture for 5 min at 37 degrees C with 0.025 mM [ 35 S]L-cystine resulted in incorporation of approximately 36 and 8.5% of the label into intracellular CSH and GSH, respectively. These cultured cells, therefore, seem to be an excellent model system for the eventual elucidation of (a) the inticacies of cystine metabolism and (b) regulation of (1) the cystine-dibasic amino acid co-transporter system and (2) the development of the cysteine-glutamate anti-porter system

Maize root culture as a model system for studying azoxystrobin biotransformation in plants

DEFF Research Database (Denmark)

Gautam, Maheswor; Elhiti, Mohamed Abdelsamad A; Fomsgaard, Inge S.

2018-01-01

Hairy roots induced by Agrobacterium rhizogenes are well established models to study the metabolism of xenobiotics in plants for phytoremediation purposes. However, the model requires special skills and resources for growing and is a time-consuming process. The roots induction process alters...... the genetic construct of a plant and is known to express genes that are normally absent from the non-transgenic plants. In this study, we propose and establish a non-transgenic maize root model to study xenobiotic metabolism in plants for phytoremediation purpose using azoxystrobin as a xenobiotic compound...

Inhibition of apoptosis using exosomes in Chinese hamster ovary cell culture.

Science.gov (United States)

Han, Seora; Rhee, Won Jong

2018-05-01

Animal cell culture technology for therapeutic protein production has shown significant improvement over the last few decades. Chinese hamster ovary (CHO) cells have been widely adapted for the production of biopharmaceutical drugs. In the biopharmaceutical industry, it is crucial to develop cell culture media and culturing conditions to achieve the highest productivity and quality. However, CHO cells are significantly affected by apoptosis in the bioreactors, resulting in a substantial decrease in product quantity and quality. Thus, to overcome the obstacle of apoptosis in CHO cell culture, it is critical to develop a novel method that does not have minimal concern of safety or cost. Herein, we showed for the first time that exosomes, which are nano-sized extracellular vesicles, derived from CHO cells inhibited apoptosis in CHO cell culture when supplemented to the culture medium. Flow cytometric and microscopic analyses revealed that substantial amounts of exosomes were delivered to CHO cells. Higher cell viability after staurosporine treatment was observed by exosome supplementation (67.3%) as compared to control (41.1%). Furthermore, exosomes prevented the mitochondrial membrane potential loss and caspase-3 activation, meaning that the exosomes enhanced cellular activities under pro-apoptotic condition. As the exosomes supplements are derived from CHO cells themselves, it is not only beneficial for the biopharmaceutical productivity of CHO cell culture to inhibit apoptosis, but also from a regulatory standpoint to diminish any safety concerns. Thus, we conclude that the method developed in this research may contribute to the biopharmaceutical industry where minimizing apoptosis in CHO cell culture is beneficial. © 2018 Wiley Periodicals, Inc.

Isolation and Characterization of Poliovirus in Cell Culture Systems.

Science.gov (United States)

Thorley, Bruce R; Roberts, Jason A

2016-01-01

The isolation and characterization of enteroviruses by cell culture was accepted as the "gold standard" by clinical virology laboratories. Methods for the direct detection of all enteroviruses by reverse transcription polymerase chain reaction, targeting a conserved region of the genome, have largely supplanted cell culture as the principal diagnostic procedure. However, the World Health Organization's Global Polio Eradication Initiative continues to rely upon cell culture to isolate poliovirus due to the lack of a reliable sensitive genetic test for direct typing of enteroviruses from clinical specimens. Poliovirus is able to infect a wide range of mammalian cell lines, with CD155 identified as the primary human receptor for all three seroytpes, and virus replication leads to an observable cytopathic effect. Inoculation of cell lines with extracts of clinical specimens and subsequent passaging of the cells leads to an increased virus titre. Cultured isolates of poliovirus are suitable for testing by a variety of methods and remain viable for years when stored at low temperature.This chapter describes general procedures for establishing a cell bank and routine passaging of cell lines. While the sections on specimen preparation and virus isolation focus on poliovirus, the protocols are suitable for other enteroviruses.

Genomic variation in recently collected maize landraces from Mexico

Directory of Open Access Journals (Sweden)

María Clara Arteaga

2016-03-01

Full Text Available The present dataset comprises 36,931 SNPs genotyped in 46 maize landraces native to Mexico as well as the teosinte subspecies Zea maiz ssp. parviglumis and ssp. mexicana. These landraces were collected directly from farmers mostly between 2006 and 2010. We accompany these data with a short description of the variation within each landrace, as well as maps, principal component analyses and neighbor joining trees showing the distribution of the genetic diversity relative to landrace, geographical features and maize biogeography. High levels of genetic variation were detected for the maize landraces (HE = 0.234 to 0.318 (mean 0.311, while slightly lower levels were detected in Zea m. mexicana and Zea m. parviglumis (HE = 0.262 and 0.234, respectively. The distribution of genetic variation was better explained by environmental variables given by the interaction of altitude and latitude than by landrace identity. This dataset is a follow up product of the Global Native Maize Project, an initiative to update the data on Mexican maize landraces and their wild relatives, and to generate information that is necessary for implementing the Mexican Biosafety Law. Keywords: Maize, Teosinte, Maize SNP50K BeadChip, Mexican landraces, Proyecto Global de Maíces Nativos

SAHA-induced TRAIL-sensitisation of Multiple Myeloma cells is enhanced in 3D cell culture.

Science.gov (United States)

Arhoma, A; Chantry, A D; Haywood-Small, S L; Cross, N A

2017-11-15

Multiple Myeloma (MM) is currently incurable despite many novel therapies. Tumour Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) is a potential anti-tumour agent although effects as a single agent are limited. In this study, we investigated whether the Histone Deacetylase (HDAC) inhibitor SAHA can enhance TRAIL-induced apoptosis and target TRAIL resistance in both suspension culture, and 3D cell culture as a model of disseminated MM lesions that form in bone. The effects of SAHA and/or TRAIL in 6 Multiple Myeloma cell lines were assessed in both suspension cultures and in an Alginate-based 3D cell culture model. The effect of SAHA and/or TRAIL was assessed on apoptosis by assessment of nuclear morphology using Hoechst 33342/Propidium Iodide staining. Viable cell number was assessed by CellTiter-Glo luminescence assay, Caspase-8 and -9 activities were measured by Caspase-Glo™ assay kit. TRAIL-resistant cells were generated by culture of RPMI 8226 and NCI-H929 by acute exposure to TRAIL followed by selection of TRAIL-resistant cells. TRAIL significantly induced apoptosis in a dose-dependent manner in OPM-2, RPMI 8226, NCI-H929, U266, JJN-3 MM cell lines and ADC-1 plasma cell leukaemia cells. SAHA amplified TRAIL responses in all lines except OPM-2, and enhanced TRAIL responses were both via Caspase-8 and -9. SAHA treatment induced growth inhibition that further increased in the combination treatment with TRAIL in MM cells. The co-treatment of TRAIL and SAHA reduced viable cell numbers all cell lines. TRAIL responses were further potentiated by SAHA in 3D cell culture in NCI-H929, RPMI 8226 and U266 at lower TRAIL + SAHA doses than in suspension culture. However TRAIL responses in cells that had been selected for TRAIL resistance were not further enhanced by SAHA treatment. SAHA is a potent sensitizer of TRAIL responses in both TRAIL sensitive and resistant cell lines, in both suspension and 3D culture, however SAHA did not sensitise TRAIL-sensitive cell

Flux analysis of mammalian cell culture

NARCIS (Netherlands)

Martens, D.E.; Tramper, J.

2010-01-01

Animal cells are used for the production of vaccines and pharmaceutical proteins. The increase in demand for these products requires an increase in volumetric productivity of animal cell culture processes, which can be attained through an increase in biomass concentration and/or specific

Strategic Marketing Problems in the Uganda Maize Seed Industry

OpenAIRE

Larson, Donald W.; Mbowa, Swaibu

2004-01-01

Strategic marketing issues and challenges face maize seed marketing firms as farmers increasingly adopt hybrid varieties in a modernizing third world country such as Uganda. The maize seed industry of Uganda has changed dramatically from a government owned, controlled, and operated industry to a competitive market oriented industry with substantial private firm investment and participation. The new maize seed industry is young, dynamic, growing and very competitive. The small maize seed marke...

Chemopreventive effects of free and bound phenolics associated to steep waters (nejayote) obtained after nixtamalization of different maize types.

Science.gov (United States)

Rojas-García, Carlos; García-Lara, Silverio; Serna-Saldivar, Sergio O; Gutiérrez-Uribe, Janet A

2012-03-01

Free and bound phenolics extracts from nejayote solids were obtained after optimally lime-cooking blue, normal white, red, normal yellow, high-carotenoid and quality protein maize types. The extraction yield ranged from 4.47 to 10.05%. Bound phenolics extracts had higher content of total phenolics, antioxidant activity and ferulic acid compared to the free phenolics extracts. In general, free phenolics extracts were less cytotoxic than the bound phenolics counterparts. Bound phenolics extracts had higher induction of quinone reductase (QR) and particularly the normal yellow nejayote exerted the highest chemopreventive index tested in Hepa1c1c7 cells. When tested for monofunctional phase 2 induction capacity in BPrc1 cells, the bound phenolics extracts of blue, normal white and quality protein nejayotes were better inducers than the normal yellow counterpart. Particularly, the free phenolics extract of the white maize nejayote induced BPrc1 cells QR and exerted a higher chemopreventive index compared to the bound phenolics extract. Therefore, the nejayote of the normal white maize was the best source of monofunctional phase 2 enzyme inducers.

Plant cell culture initiation

NARCIS (Netherlands)

Hall, R.D.

2000-01-01

The use of cultured plant cells in either organized or unorganized form has increased vey considerably in the last 10-15 yr. Many new technologies have been developed and applications in both fundamental and applied research have led to the development of some powerful tools for improving our

Differentiation of Human Pluripotent Stem Cells into Functional Endothelial Cells in Scalable Suspension Culture

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Ruth Olmer

2018-05-01

Full Text Available Summary: Endothelial cells (ECs are involved in a variety of cellular responses. As multifunctional components of vascular structures, endothelial (progenitor cells have been utilized in cellular therapies and are required as an important cellular component of engineered tissue constructs and in vitro disease models. Although primary ECs from different sources are readily isolated and expanded, cell quantity and quality in terms of functionality and karyotype stability is limited. ECs derived from human induced pluripotent stem cells (hiPSCs represent an alternative and potentially superior cell source, but traditional culture approaches and 2D differentiation protocols hardly allow for production of large cell numbers. Aiming at the production of ECs, we have developed a robust approach for efficient endothelial differentiation of hiPSCs in scalable suspension culture. The established protocol results in relevant numbers of ECs for regenerative approaches and industrial applications that show in vitro proliferation capacity and a high degree of chromosomal stability. : In this article, U. Martin and colleagues show the generation of hiPSC endothelial cells in scalable cultures in up to 100 mL culture volume. The generated ECs show in vitro proliferation capacity and a high degree of chromosomal stability after in vitro expansion. The established protocol allows to generate hiPSC-derived ECs in relevant numbers for regenerative approaches. Keywords: hiPSC differentiation, endothelial cells, scalable culture

Electrospinning PCL Scaffolds Manufacture for Three-Dimensional Breast Cancer Cell Culture

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Marc Rabionet

2017-08-01

Full Text Available In vitro cell culture is traditionally performed within two-dimensional (2D environments, providing a quick and cheap way to study cell properties in a laboratory. However, 2D systems differ from the in vivo environment and may not mimic the physiological cell behavior realistically. For instance, 2D culture models are thought to induce cancer stem cells (CSCs differentiation, a rare cancer cell subpopulation responsible for tumor initiation and relapse. This fact hinders the development of therapeutic strategies for tumors with a high relapse percentage, such as triple negative breast cancer (TNBC. Thus, three-dimensional (3D scaffolds have emerged as an attractive alternative to monolayer culture, simulating the extracellular matrix structure and maintaining the differentiation state of cells. In this work, scaffolds were fabricated through electrospinning different poly(ε-caprolactone-acetone solutions. Poly(ε-caprolactone (PCL meshes were seeded with triple negative breast cancer (TNBC cells and 15% PCL scaffolds displayed significantly (p < 0.05 higher cell proliferation and elongation than the other culture systems. Moreover, cells cultured on PCL scaffolds exhibited higher mammosphere forming capacity and aldehyde dehydrogenase activity than 2D-cultured cells, indicating a breast CSCs enrichment. These results prove the powerful capability of electrospinning technology in terms of poly(ε-caprolactone nanofibers fabrication. In addition, this study has demonstrated that electrospun 15% PCL scaffolds are suitable tools to culture breast cancer cells in a more physiological way and to expand the niche of breast CSCs. In conclusion, three-dimensional cell culture using PCL scaffolds could be useful to study cancer stem cell behavior and may also trigger the development of new specific targets against such malignant subpopulation.

Development of an automated chip culture system with integrated on-line monitoring for maturation culture of retinal pigment epithelial cells

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Mee-Hae Kim

2017-10-01

Full Text Available In cell manufacturing, the establishment of a fully automated, microfluidic, cell culture system that can be used for long-term cell cultures, as well as for process optimization is highly desirable. This study reports the development of a novel chip bioreactor system that can be used for automated long-term maturation cultures of retinal pigment epithelial (RPE cells. The system consists of an incubation unit, a medium supply unit, a culture observation unit, and a control unit. In the incubation unit, the chip contains a closed culture vessel (2.5 mm diameter, working volume 9.1 μL, which can be set to 37 °C and 5% CO2, and uses a gas-permeable resin (poly- dimethylsiloxane as the vessel wall. RPE cells were seeded at 5.0 × 104 cells/cm2 and the medium was changed every day by introducing fresh medium using the medium supply unit. Culture solutions were stored either in the refrigerator or the freezer, and fresh medium was prepared before any medium change by warming to 37 °C and mixing. Automated culture was allowed to continue for 30 days to allow maturation of the RPE cells. This chip culture system allows for the long-term, bubble-free, culture of RPE cells, while also being able to observe cells in order to elucidate their cell morphology or show the presence of tight junctions. This culture system, along with an integrated on-line monitoring system, can therefore be applied to long-term cultures of RPE cells, and should contribute to process control in RPE cell manufacturing.

[Biological characteristics of mesenchymal stem cell and hematopoietic stem cell in the co-culture system].

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Wei, Wei; Xu, Chao; Ye, Zhi-Yong; Huang, Xiao-Jun; Yuan, Jia-En; Ma, Tian-Bao; Lin, Han-Biao; Chen, Xiu-Qiong

2016-10-25

The aim of the present study was to obtain the qualified hematopoietic stem/progenitor cells (HSC/HPC) and human umbilical cord-mesenchymal stem cells (MSC) in vitro in the co-culture system. Cord blood mononuclear cells were separated from umbilical cord blood by Ficoll lymphocyte separation medium, and then CD34 + HSC was collected by MACS immunomagnetic beads. The selected CD34 + HSC/HPC and MSC were transferred into culture flask. IMDM culture medium with 15% AB-type cord plasma supplemented with interleukin-3 (IL-3), IL-6, thrombopoietin (TPO), stem cell factor (SCF) and FMS-like tyrosine kinase 3 ligand (Flt-3L) factors were used as the co-culture system for the amplification of HSC/HPC and MSC. The cellular growth status and proliferation on day 6 and 10 after co-culture were observed by using inverted microscope. The percentage of positive expression of CD34 in HSC/HPC, as well as the percentages of positive expressions of CD105, CD90, CD73, CD45, CD34 and HLA-DR in the 4 th generation MSC, was tested by flow cytometry. Semisolid colony culture was used to test the HSC/HPC colony forming ability. The osteogenic, chondrogenesis and adipogenic ability of the 4 th generation MSC were assessed. The karyotype analysis of MSC was conducted by colchicines. The results demonstrated that the HSC/HPC of co-culture group showed higher ability of amplification, CFU-GM and higher CD34 + percentage compared with the control group. The co-cultured MSC maintained the ability to differentiate into bone cells, fat cells and chondrocytes. And the karyotype stability of MSC remained normal. These results reveal that the appropriate co-culture system for MSC and HSC is developed, and via this co-culture system we could gain both two kinds of these cells. The MSCs under the co-culture system maintain the biological characteristics. The CFU-GM ability, cell counting and the flow cytometry results of HSC/HPC under the co-culture system are conform to the criterion, showing that

Production of betalaines by Myrtillocactus cell cultures. Passage from heterotrophic state to autotrophic state with Asparagus cell cultures

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Bulard, C; Mary, J; Chaumont, D; Gudin, C

1982-11-01

Myrtillocactus tissue cultures are grown from the epicotyl of young plantlets. With an appropriate growing medium it is possible, after transfer of fragments of these cultures to a liquid environment, to obtain dissociation and proliferation of cells. The production of betalaic pigments is induced in solid surroundings by adjustement of the growing medium composition and can be maintained in a liquid environment. The multiplication of pigmented cells in suspension may thus be obtained. The conversion of Asparagus cell suspensions from the heterotrophic state (use of lactose as source of carbon) to the autotrophic state (carbon supplied by CO/sub 2/) is obtained by a gradual reduction in the sugar concentration of the medium combined with a rise in the CO/sub 2/ content of the gas mixture atmosphere injected into the cultivator. The passage to the autotrophic state of a Myrtillocactus suspension would enable the production conditions of a metabolite (Betalaine) to be studied by micro-algae culture techniques.

Maize production in mid hills of Nepal: from food to feed security

OpenAIRE

Krishna Prasad Timsina; Yuga Nath Ghimire; Jeevan Lamichhane

2016-01-01

This study was undertaken in 2016 to analyze the production and utilization of maize in Nepal. Sixty maize growers from Kavre and Lamjung districts were selected using purposive, cluster and simple random sampling techniques. Similarly, six feed industries and five maize experts from Chitwan district were also interviewed. Study shows 56% of the total areas were used for maize production and 50% of the maize areas were covered by hybrid maize. There was no practice of contract maize productio...

Hypoxic contraction of cultured pulmonary vascular smooth muscle cells

International Nuclear Information System (INIS)

Murray, T.R.; Chen, L.; Marshall, B.E.; Macarak, E.J.

1990-01-01

The cellular events involved in generating the hypoxic pulmonary vasoconstriction response are not clearly understood, in part because of the multitude of factors that alter pulmonary vascular tone. The goal of the present studies was to determine if a cell culture preparation containing vascular smooth muscle (VSM) cells could be made to contract when exposed to a hypoxic atmosphere. Cultures containing only fetal bovine pulmonary artery VSM cells were assessed for contractile responses to hypoxic stimuli by two methods. In the first, tension forces generated by cells grown on a flexible growth surface (polymerized polydimethyl siloxane) were manifested as wrinkles and distortions of the surface under the cells. Wrinkling of the surface was noted to progressively increase with time as the culture medium bathing the cells was made hypoxic (PO2 approximately 25 mmHg). The changes were sometimes reversible upon return to normoxic conditions and appeared to be enhanced in cells already exhibiting evidence of some baseline tone. Repeated passage in culture did not diminish the hypoxic response. Evidence for contractile responses to hypoxia was also obtained from measurements of myosin light chain (MLC) phosphorylation. Conversion of MLC to the phosphorylated species is an early step in the activation of smooth muscle contraction. Lowering the PO2 in the culture medium to 59 mmHg caused a 45% increase in the proportion of MLC in the phosphorylated form as determined by two-dimensional gel electrophoresis. Similarly, cultures preincubated for 4 h with 32P and then exposed to normoxia or hypoxia for a 5-min experimental period showed more than twice as much of the label in MLCs of the hypoxic cells

Selection of diazotrophic bacteria isolated from wastewater treatment plant sludge at a poultry slaughterhouse for their effect on maize plants

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Jorge Avelino Rodriguez Lozada

Full Text Available ABSTRACT The economic and environmental costs of nitrogen fertilization have intensified the search for technologies that reduce mineral fertilization, for example atmospheric nitrogen-fixing (diazotrophic bacteria inoculation. In this context, the present study addressed the isolation and quantification of diazotrophic bacteria in the sludge from treated wastewater of a poultry slaughterhouse; a description of the bacteria, based on cell and colony morphology; and an assessment of growth and N content of maize plants in response to inoculation. Sixteen morphotypes of bacteria were isolated in six N-free culture media (JMV, JMVL, NFb, JNFb, LGI, and LGI-P. The bacteria stained gram-positive, with 10 rod- and six coccoid-shaped isolates. To evaluate the potential of bacteria to promote plant growth, maize seeds were inoculated. The experiment consisted of 17 treatments (control plus 16 bacterial isolates and was carried out in a completely randomized design with six replicates. The experimental units consisted of one pot containing two maize plants in a greenhouse. Forty-five days after planting, the variables plant height, leaf number, stem diameter, root and shoot fresh and dry weight, and N content were measured. The highest values were obtained with isolate UFV L-162, which produced 0.68 g total dry matter per plant and increased N content to 22.14 mg/plant, representing increments of 74 and 133%, respectively, compared with the control. Diazotrophs inhabit sludge from treated wastewater of poultry slaughterhouses and can potentially be used to stimulate plant development and enrich inoculants.

Analysis of B chromosome nondisjunction induced by the r-X1 deficiency in maize.

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Tseng, Shih-Hsuan; Peng, Shu-Fen; Cheng, Ya-Ming

2017-11-20

The maize B chromosome typically undergoes nondisjunction during the second microspore division. For normal A chromosomes, the r-X1 deficiency in maize can induce nondisjunction during the second megaspore and first microspore divisions. However, it is not known whether the r-X1 deficiency also induces nondisjunction of the maize B chromosome during these cell divisions. To answer this question, chromosome numbers were determined in the progeny of r-X1/R-r female parents carrying two B chromosomes. Some of the r-X1-lacking progeny (21.2%) contained zero or two B chromosomes. However, a much higher percentage of the r-X1-containing progeny (43.4%) exhibited zero or two B chromosomes, but none displayed more than two B chromosomes. Thus, the results indicated that the r-X1 deficiency could also induce nondisjunction of the B chromosome during the second megaspore division; moreover, the B chromosome in itself could undergo nondisjunction during the same division. In addition, pollen grains from plants with two B chromosomes lacking or exhibiting the r-X1 deficiency were compared via pollen fluorescence in situ hybridization (FISH) using a B chromosome-specific probe. The results revealed that the r-X1 deficiency could induce the occurrence of B chromosome nondisjunction during the first microspore division and that the B chromosome in itself could undergo nondisjunction during the same division at a lower frequency. Our data shed more light on the behavior of the maize B chromosome during cell division.

Contributions of 3D Cell Cultures for Cancer Research.

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