Engineering lysine‐rich caleosins as carrier proteins to render biotin as a hapten on artificial oil bodies for antibody production

It has been demonstrated that caleosin alone is sufficient to stabilize artificial oil bodies. A series of recombinant caleosins, mutated with 3, 5, 8, 11, 13, 15, and 17 extra Lys residues and over‐expressed in Escherichia coli, were used as carrier proteins to render biotin as a hapten on the surface of artificial oil bodies for antibody production. Biotinylation levels of the recombinant caleosins were step‐wisely elevated as the number of extra Lys residues increased, and the biotinylated Lys residues were identified by mass spectrometric analysis. Polyclonal antibodies against biotin were successfully generated in rats injected with artificial oil bodies constituted with each of the biotinylated caleosins. Moreover, those generated via the biotinylated caleosins with eight or more extra Lys residues no longer recognized caleosin. It appears that engineered Lys‐rich caleosins are suitable carrier proteins for the production of antibodies against small molecules. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011     

Propagation of Geotrichum candidum in Acid Brine

Geotrichum candidum completely neutralized the acid brine and reduced its biochemical oxygen demand (BOD) by 88%. Yield of dry mycelium was 62 g per 100 g of BOD utilized.     

Grape pomace: A novel substrate for microbial production of citric acid

Summary Grape pomace was used as substrate for microbial production of citric acid. Of the five cultures examined,Aspergillus niger NRRL 567 was found to produce the greatest amount of citric acid from grape pomace in the presence of methanol at a concentration of 3% (vol/wt). The yield was 60% based on the amount of fermentable sugar consumed.     

In vitro growth and differentiation of human kidney tubular cells on a basement membrane substrate

Summary Kidney cortical tubular cells, mainly proximal tubular cells, isolated from human kidney and grown either on a basement membrane substrate in chemically defined medium or on plastic in serum-supplemented medium, had substantial proliferative potential and could be propagated for more than 10 generations or 8 passages before senescence. Basement membrane produced on a plastic substrate by the HR-9 endodermal cell line could replace serum supplementation in promoting tubular cell growth. Tubular cells grown on an HR-9 basement membrane substrate exhibited stable epithelial morphology over an extended period of time; in the presence of 5% serum they differentiated into organized structures such as hemicysts and cell cords. Cells grown on plastic failed to differentiate and gradually degenerated. Tubular cells on HR-9 basement membrane were characterized by densely packed microvilli, abundant rough endoplasmic reticulum and free polysomes, basal cell membrane interdigitations, a well-developed endocytotic apparatus, and conspicuous junctional complexes—all features of the proximal tubular cell. Compared with cells on plastic substrate, there were higher levels of the brush border enzymes γ-glutamyl transpeptidase,l-leucine aminopeptidase, and alkaline phosphatase in cells maintained on an HR-9 basement membrane substrate, further supporting the conclusion that a basement membrane substrate promoted differentiation of tubular cells. These data and morphological observations indicate that a basement membrane substrate can promote growth and both functional and morphologic differentiation of human kidney tubular cells. This work was supported by the Veterans Administration.     

宁夏同心中新世铲齿象化石

本文记述了宁夏同心地区中中新世哺乳动物群中铲齿象化石——同心铲齿象 (Platybelodon tongxinensis) (原定为同心嵌齿象 (Gomphotherium tongxinensis). 通过与国内外已现的有关铲齿象对比,确认其与国内已发现的葛氏种关系最近,可能属同一枝系.同心种与葛氏种相比,是性质相对原始分布层位较低的我国第二个铲齿象种.文章初步讨论了其 M_3 的某些变异性状.并结合现有的其它标本初步阐述了铲齿象类下门齿的两种结构类型,原始型的同心层状结构和衍生型的齿质柱状结构.建议根据这两种结构仍将铲齿象类划分为 Platybelodontinae 和 Amebelodontinae.     

Production of citric acid by immobilized dried reactivatedAspergillus niger

Summary Immobilization followed by drying was fried as a new technique for obtaining small beads which might be more suitable for industrial fermentations and for the storage of the immobilized microorganisms.Aspergillus niger NRRL 2270 was used to produce citric acid in free, immobilized, and immobilized dried reactivated (IDR) forms. The productivity based on the bead volume used increased several folds with the use of IDR cells although the absolute level of citric acid did not increase.     

A process for leaching citric acid from apple pomace fermented withAspergillus niger in solid-state culture

Summary A multiple contact countercurrent process was developed for leaching citric acid from apple pomace fermented withAspergillus niger in solid-state culture. Acetone was found to be the most efficient among the different solvents examined as it yielded the greatest amount of citric acid in the leachate and gave an extraction efficiency of 90%.

---

Un procédé pour lixivier l'acide citrique de la purée de pommes fermentée par Aspergillus niger en milieu solide

Résumé On développe un procédé à contacts multiples par contrecourant pour lixivier l'acide citrique de la purée de pommes fermentée parAspergillus niger en milieu solide. L'acétone se révèle être le solvent le plus efficace parmi différents solvents examinés car il donne les quantités les plus élevées d'acide citrique dans le lixiviat et une efficacité d'extraction de 90%.

     

Strain improvement of Rhizopus oryzae for production of l(+)-lactic acid and glucoamylase

Thirty-eight l(+)-lactic acid-overproducing mutants were isolated by mutagenizing a parent strain of Rhizopus oryzae NRRL 395 with u.v. and/or N -methyl- N '-nitro- N -nitrosoguanidine. Three mutants, 1N1, 3N4 and 3N6, were found to yield significantly more l(+)-lactic acid in a rice medium than the parent strain. Of the mutants examined, only mutant 3N4 produced more glucoamylase than the parent strain.