Hydrolysis of Butteroil by Immobilized Lipase Using a Hollow-Fiber Reactor: Part VI. Multiresponse Analyses of Temperature and pH Effects

A lipase from Aspergillus niger, immobilized by physical adsorption on hydrophobic hollow fibers made of microporous polypropylene, was used to effect the hydrolysis of the glycerides of melted butterfat at 40, 50, 55, and 60°C (pH 7.0), and at pH 3.0, 4.0, 5.0, 7.0, 8.0, and 9.0 (40°C). McIlvane buffer and melted butterfat were pumped cocurrently through the hollow fiber reactor. The concentrations of ten different free fatty acids in the effluent oil stream were measured by HPLC. Multiresponse nonlinear regression methods were employed to fit the data to multisubstrate rate expressions derived from a Ping Pong Bi Bi mechanism in which the rate controlling step is deacylation of the enzyme. Thermal deactivation of the immobilized lipase was also included in the mathematical model of reactor performance. A postulated normal distribution of v_max with respect to the number of carbon atoms of the fatty acid residue (with an additive correction for the number of double bonds) was found to provide the best statistical fit of the data. The models developed can be used to independently predict the effects of either the pH or the temperature, as well as the reactor space time and the time elapsed after immobilization, on the free fatty acid profile of the lipolyzed butteroil product.     

Influence of ovule perforation,plant growth regulators,andl-glutamine on in vitro growth of immature peach embryos

Summary Ovule perforation technique and media components (plant growth regulators andl-glutamine) were tested on in vitro growth of immature (<3 mm) embryos of “Springcrest” and “Earligrande” peaches. Ovule perforation was 2 to 4 times more effective in promoting embryo growth than leaving ovules intact.l-Glutamine (400 mg·liter⁻¹) promoted an increase in growth but could not be used with indole-acetic acid plus kinetin because an antagonistic effect on embryo growth occurred. The use of these exogenous plant growth regulators did not increase embryo growth over in vivo growth.     

Specific induction of self-discrimination by follicle cells in Ciona intestinalis oocytes

Self-incompatibility, a mechanism that prevents self-fertilization in ascidians, is based on the ability of the oocyte vitelline coat to distinguish and accept only heterologous spermatozoa. In Ciona intestinalis self-discrimination is established during late oogenesis and is contributed or controlled by products of the overlying follicle cells. In this study we have further investigated the role of the follicle cells in the onset of self-discrimination by using in vitro maturation of ovarian oocytes deprived of the follicle cells and incubated with either autologous or heterologous follicle cells. Fertilization assays demonstrate that the action of the follicle cells is exerted even when they are detached from the vitelline coat and that only autologous follicle cells can promote the induction of self-sterility on the egg coat. Electron microscopy of the oocytes during maturation reveals that the switch from self-fertility to self-sterility is accompanied by the appearance of a thin electron-dense layer on the outer surface of the vitelline coat. We suggest that the formation of this layer is the result of the interaction between products of the follicle cells and the autologous vitelline coat.     

Cyclooxygenase and lipoxygenase metabolite generation in nasal polyps

A role of prostaglandins (PGs) and leukotrienes (LTs) in the pathogenesis of nasal polyps has been recently suggested. Cyclooxygenase (CO) products (thromboxane B₂, PGE₂ and 6-keto PGF₁ alpha) and lipoxygenase (LO) products (LTB₄ and LTC₄) were investigated by radioimmunoassay in polyps, hypertrophic turbinates and nasal mucosa from 14 patients with non-allergic (n = 6), allergic chronic rhinitis (n = 6) and aspirin-sensitive asthma (ASA) (n = 2), who underwent polypectomy. In all tissues CO metabolite levels were found higher than LO products (P < 0.01). Nasal polyps showed a significantly lower (P < 0.05) arachidonic acid (AA) metabolism in comparison to nasal mucosa. In polyps of allergic patients significantly higher LTB₄ levels (P < 0.001) and a tendency to produce higher amounts of CO products in comparison to non-allergic subjects were observed, whereas in turbinates of non-allergic patients LT levels were significantly higher in comparison to those of allergic ones (P < 0.01). In ASA patients a decreased ratio was found supporting the hypothesis of an imbalance of AA metabolism in this syndrome. These findings seem to indicate that the occurrence of nasal polyps may represent the result of different chronic inflammatory stimuli, regulated in part by AA metabolites.     

Anti-Hepatitis A Virus Antibody Response Elicited in Mice by Different Forms of a Synthetic VP1 Peptide

Peptide VP1 (11-25) of the capsid of hepatitis A virus was synthesized by the Fmoc-polyamide solid phase method, and administered to mice in different forms: (1) free, (2) encapsulated in multilamellar liposomes, (3) coupled to keyhole limpet hemocyanin (KHL), and (4) incorporated into a tetrameric branched lysine core. The highest anti-VP1 peptide responses were generated by synthetic peptides entrapped into liposomes and coupled to KLH. No anti-HAV response was generated with the free peptide, while all the other forms induced both anti-HAV and HAV-neutralizing antibodies. Maximum neutralization indices were observed in ascites from mice treated with liposome-entrapped and KLH peptides.     

Composition and properties of Albizia lebbeck gum exudate

An analytical study has been made of six gum specimens from Albizia lebbeck, Leguminosae. Galactose, mannose, arabinose, glucuronic acid and its 4-O--metyl analogue are present in all the specimens studied. Rhamnose was not detected according to sugar analysis and spectral data. The absence of this sugar, the high acidity and the relatively low limit viscosity number contrast with the values reported previously for one African sample of A. lebbeck. The lead content is much higher than that recorded for other Albizia gums. ¹³C-NMR spectrum of this gum, in deuterium oxide, shows good resolution.     

Transferable clastogenic activity in plasma from patients with Fanconi anemia

The present study was conducted on 13 patients with Fanconi anemia, 25 parents and 12 siblings. The chromosomal instability characteristic of this congenital breakage syndrome was associated with the presence of transferable clastogenic material in the plasma, as also reported previously for ataxia telangiectasia and Bloom's syndrome. While all plasma ultrafiltrates from homozygotes had chromosome damaging properties, the clastogenic material had to be concentrated in most heterozygotes to reach detectable levels. The clastogenic effect was exerted via the intermediacy of superoxide radicals, since it was regularly inhibited by superoxide dismutase (SOD). This adds further evidence for a prooxidant state in this hereditary disease. The autosustained clastogenic activity possibly plays a role in the progressive impairment of blood cell-producing bone marrow and may predispose patients to develop cancer and leukemia. Prophylactic use of antioxidants may be recommended, using clastogenic plasma activity as a guide.     

Nodular pulmonary amyloidosis.

An elderly man had a 10-year history of multiple pulmonary nodules that he had refused to have investigated. He died of a ruptured abdominal aortic aneurysm. At autopsy the nodules were shown to consist of amyloid. There was no evidence of systemic amyloidosis.