Development of a fructose based medium for biosynthesis of cyclosporin-A byBeauveria nivea

Summary A new fructose based medium was developed to growBeauveria nivea ATCC 34921 for the production of Cyclosporin A (CyA). Two different sugars and three different nitrogen sources were used for CyA production. Different pH levels in the broth revealed that the best pH for CyA production was 5.5. Maximum concentration of 170 mg CyA/L of broth was obtained with the new medium in 8 days corresponding to yields of 14.8 mg CyA/g dry weight biomass and 5.67 mg CyA/g fructose supplied.     

The eggshell of the cherry fly Rhagoletis cerasi

One of the major pests in Greek cherry orchards is the cherry fly Rhagoletis cerasi (Diptera: Tephritidae). In order to complete our comparative work on the chorion assembly of other representatives of the fruit flies (e.g. Ceratitis capitata and Dacus oleae) we studied eggshell morphogenesis in the cherry fly. The oocyte is surrounded by several distinct layers which are produced during choriogenesis. The eggshell consists of the vitelline membrane, a fibrous layer of possible water-proofing function, an innermost chorionic layer, endochorionic and exochorionic layers. The endochorion shows a branched configuration with irregular cavities, and the exochorion consists of inner and outer layers for better embryo protection. At the anterior region of the follicle, the hexagonal borders of the follicle cells are created by endochorionic material, covered by both inner and outer exochorion. This area resembles the D. melanogaster chorionic appendages and therefore can serve for plastron respiration. The structural results support the phylogenetic relationships among the tephritids (Rhagoletis is closer to Ceratitis than Dacus). The presence of peroxidase in the endochorion, detected by diaminobenzidine, is consistent with the eggshell hardening at the end of choriogenesis, following the same pattern with the other fruit flies studied so far. Two major chorionic proteins are found both in R. cerasi and in C. capitata and therefore general conclusions can be drawn from this study, concerning the pattern of choriogenesis, which all dipteran insects follow, in order to create a resistant and functional eggshell, and the high conservation of the proteinaceous components of the chorion among species in the order.     

Effect of temperature and pH on immobilized Zymomonas mobilis for continuous production of ethanol

The effects of temperature and inlet pH of the medium on the ethanol productivity and activity of the immobilized Z. mobilis cells during continuous fermentation of glucose have been studied at various temperatures and pH. On changing the temperature from one steady state level to a new one, 6-8 h were required in order to fully experience the effect of a change in temperature; whereas 8-20 h were required on changing the pH. The optimum temperature of 37 degrees C and a broad pH range of 4.4-6.0 were observed for maximum ethanol productivity and ethanol yield.     

Improvement of inulinase stability of calcium alginate immobilized Kluyveromyces marxianus cells by treatment with hardening agents

To improve the inulinase (2,1-β-d-fructan fructanohydrolase, EC 3.2.1.7) stability of calcium alginate-immobilized Kluyveromyces marxianus cells, treatment with hardening agents has been investigated. Treatment of immobilized cells with some polycationic polymers resulted in little decrease in volumetric reactor productivity, but was most effective in increasing the inulinase stability of the immobilized cells. Inulinase stability of glutaraldehyde-hardened immobilized cells increased two-fold, and for hexamethylenediamine + glutaraldehyde and polyethyleneimine + glutaraldehyde-hardened cells increased six-fold compared with that of the unhardened cells.     

Isolation and Characterization of Sex-Linked Female-Sterile Mutants in DROSOPHILA MELANOGASTER with Special Attention to Eggshell Mutants

To study genes that function mainly or exclusively during oogenesis, we have isolated and analyzed female-sterile mutations, with special emphasis on those that affect eggshell formation. Following treatment that induced 61 to 66% lethals, 8.1% of the 1071 X chromosomes tested carried recessive female sterility mutations (87 isolates), and 8.0% carried partial female-sterile mutations (86 isolates), respectively. In addition, three dominant female steriles were recovered. Some of the mutants had very low fecundity, and others laid morphologically normal eggs that failed to develop. A third category included 29 mutants that laid eggs with morphological abnormalities: 26 were female steriles, two were partial female steriles and one was fertile. Mutants of this third category were characterized in some detail and compared with 40 previously isolated mutants that laid similarly abnormal eggs. Approximately 28–31 complementation groups with morphological abnormalities were detected, some of which were large allelic series (11, 9, 7, 6 and 5 alleles). Twenty-four groups were mapped genetically or cytogenetically, and 21 were partially characterized by ultrastructural and biochemical procedures. Of the latter, one group showed clear deficiency of yolk proteins, and nine showed prominent ultrastructural defects in the chorion (at least eight accompanied by deficiencies in characterized chorion proteins). At least six groups with clear-cut effects were found at loci not previously identified with known chorion structural genes.     

High ethanol productivities using small Ca-alginate beads of immobilized cells of Zymomonas mobilis

Summary Zymomonas mobilis cells were immobilized into small 1 mm diameter beads of Ca-alginate in order to minimize mass transfer limitations and maximize immobilized cell activity. A combination of small bead size with a high cell concentration of 58 g dry wt. cell per lit. bead volume resulted in high ethanol productivities using a newly designed packed bed bioreactor system. Steady-state dilution rates ranging from 0.4 h^-1 to 3.9 h^-1 were run resulting in a maximum productivity of 102 g ethanol/l/h for an inlet substrate concentration of 100 g glu/l and 87% conversion. The bioreactor was run continuously at a fixed dilution rate for 384 h and short intermittent treatment of the beads with CaCl₂ temporarily increased ethanol productivity to a maximum of 116 g ethanol/l/h.     

Fine structure of the chorion of Manduca sexta and Sesamía nonagrioides as revealed by scanning electron microscopy and freeze-fracturing

The fine structure of Manduca sexta and Sesamia nonagrioides chorion was investigated by scanning electron microscopy and freeze-fracturing. In both species the mature chorion exhibits a complex ultrastructure on its outer surface, with a large number of aeropyles forming polygonal arrays. The micropyle is surrounded by a rosette of approximately 80 follicular cell imprints. Scanning electron microscopy of vertically ripped sections reveals that both chorions consist of two main layers: a trabecular layer closest to the oocyte and a lamellar layer. The technique of freeze-fracturing, utilizing single-sided and rotary shadowing, clearly shows that fibrils, approximately 3-4 nm in diameter, constitute chorionic lamellae in both species. The fibrils appear to have a 'beaded' structure, with a 2-3 nm axial periodicity. Freeze-fracturing also provides a direct visualization of the helicoidal arrangement of these fibrils for the formation of chorion supramolecular architecture.     

In vitro development of theDrosophila chorion in a chemically defined organ culture medium

Summary TheDrosophila chorion is produced normally in isolated follicles in Robb's chemically defined culture medium. The complex architecture of the shell developed in vitro from follicles as young as early stage 10 is completely normal morphologically. In addition, the time required for in vitro development closely approximates that observed for in vivo development. Comparisons of insect culture media developed by Robb, Grace, Schneider, and Echalier show large variations in their ability to supportDrosophila chorion development.     

Quantitative changes and ultrastructural alterations of the cornea in response to ultraviolet light II. Effects on amphibia; elucidation of desmosomal structure and basement membrane synthesis

The cornea of the urodele amphibian Triturus c. cristatus was studied ultrastructurally in order to provide the basis for a comparison among corneas throughout the vertebrate phylum. The cornea of this salamander consists of relatively thick epithelium and basement membrane and thin Descemet's membrane, unlike the mammalian corneas. The outermost epithelial cells contain Ruthenium Red stainable extracellular filaments and intracellular vesicles which are thought to play a role in the process of lubricating the corneal surface. Occluding junctions have been observed in the apical region of the superficial epithelial cells and are considered as barriers to the intercellular passage of material. A thin substantia propria (stroma) consists of about 40 collagenous highly organized lamellae. The thicknesses of the basement membrane, Descemet's membrane and the epithelium are believed to represent the primitive situation in the process of corneal evolution.