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At least 343 records · Page 19Linked to original sources
PubMed2005

An antarctic psychrotrophic bacterium Halomonas sp. ANT-3b, growing on n-hexadecane, produces a new emulsyfying glycolipid.

A bacterial strain ANT-3b was isolated at the sea-ice seawater interface from Terra Nova Bay station, Ross Sea, Antarctica. It was isolated on mineral medium supplemented with 2% diesel fuel as a sole carbon and energy source and grown routinely on 2% n-hexadecane. Analysis of 16S rRNA gene sequence indicates that the strain has 99.8% sequence similarity with Halomonas neptunia. The strain ANT-3b was grown in mineral medium supplemented with n-hexadecane between 4 and 20 degrees C, but not at 30 degrees C. The maximum degradation rate of the n-alkane was measured at 15 degrees C, with 5.6+/-1.7 mg O2 microg(-1) protein d(-1). The strain ANT-3b produced emulsifying compounds when grown on n-hexadecane, but not on mineral medium supplemented with D-fructose. A preliminary characterisation of the emulsifier was carried out. The lipid moiety contained a mixture of fatty acids with a following composition in molar ratio: caprylic acid 18.85, myristic acid 1.0, palmitic acid 9.68, palmitoleic acid 5.69 and oleic acid 1.26. The polysaccharide moiety also contained a mixture of sugars with the following molar ratio: mannose 1.71, galactose 1.00 and glucose 2.96. The molecular weight of the glycolipid component determined by gel permeation chromatography was in the 18 kDa range and contained smaller fragments, possibly oligomeric contaminants. Transmission electron microscopy showed contact between the glycolipid secreted by the strain and n-hexadecane broken down to nanodroplets at the water interface, to form a material with mesophase (liquid crystal) organisation.

Alkanes↗
PubMed2004

A novel thermostable esterase from the thermoacidophilic archaeon Sulfolobus tokodaii strain 7.

We have characterized an esterase expressed from the putative esterase gene (ST0071) selected from the total genome analysis from the thermoacidophilic archaeon Sulfolobus tokodaii strain 7. The ORF was cloned and expressed as a fusion protein in Escherichia coli. The protein was purified with heat treatment, affinity column chromatography, and size exclusion filtration. The optimum activity for ester cleavage against p-nitrophenyl esters was observed at around 70 degrees C and pH 7.5-8.0. The enzyme exhibited high thermostability and also showed activity in a mixture of a buffer and water-miscible organic solvents, such as acetonitrile and dimethyl sulfoxide. From the kinetic analysis, p-nitrophenyl butyrate was found to be a better substrate than caproate and caprylate.

Cloning, Molecular↗
PubMed2003

Juvenile hormone (JH) esterase: why are you so JH specific?

Juvenile hormone esterases (JHEs) from six insects belonging to three orders (Lepidoptera, Coleoptera, and Diptera) were compared in terms of their deduced amino acid sequence and biochemical properties. The four lepidopteran JHEs showed from 52% to 59% identity to each other and about 30% identity to the coleopteran and dipteran JHEs. The JHE of Manduca sexta was remarkably resistant to the addition of organic co-solvents and detergent; in some cases, it demonstrated significant activation of activity. Trifluoromethylketone (TFK) inhibitors with chain lengths of 8, 10 or 12 carbons were highly effective against both lepidopteran and coleopteran JHEs. The coleopteran JHE remained sensitive to TFK inhibitors with a chain length of 6 carbons, whereas the lepidopteran JHEs were significantly less sensitive. When the chain was altered to a phenethyl moiety, the coleopteran JHE remained moderately sensitive, while the lepidopteran JHEs were much less sensitive. The lepidopteran and coleopteran JHEs did not show dramatic differences in specificity to alpha-naphthyl and rho-nitrophenyl substrates. However, as the chain length of the alpha-naphthyl substrates increased from propionate to caprylate, there was a trend towards reduced activity. The JHE of M. sexta was crystallized and the properties of the crystal suggest a high-resolution structure will follow.

Amino Acid Sequence↗
PubMed2005

IGIV: contents, properties, and methods of industrial production--evolving closer to a more physiologic product.

Is the process the product? Immune globulin intravenous (IGIV) is not manufactured, but is purified (fractionated) from human plasma. Machines can only damage what Mother Nature makes; they cannot improve it. Therefore, fractionators of biologic molecules must strive to ensure what is taken from a human body is exactly the same when it is returned to the human body for optimal tolerability and safety. The processes of purification have the potential to adversely affect the product. Four primary purification processes exist for commercial IGIV. The Cohn-Oncley process is 1940s technology, which has been modified through the decades, but the basic process remains unchanged. The Kistler-Nitschmann process was developed in the 1950s by the Central Laboratory of the Swiss Red Cross (ZLB, today known as ZLB-Behring, a subsidiary of CSL Limited). Various attempts have been made to utilize chromatography as the sole separation technology without much success. Most recently, Bayer HealthCare (Talecris Biotherapeutics acquired the contributed assets of the worldwide plasma business of Bayer Biological Products and became operational April 1, 2005; all plasma-based products, including Gamunex, Prolastin, the hyperimmune line (Fraction II), Plasbumin (Bayer Albumin), Koate DVI, and Thrombate III were included) introduced a new product into the United States and Canada that utilizes caprylate and chromatography for high purity, better yields, and integration of safety and efficacy. This is the first new IGIV purification technology in over 20 years.

Drug Industry↗
PubMed2006

Investigation of fatty acid esters to replace isopropyl myristate in the sterility test for ophthalmic ointments.

Several pharmacopoeias recommend the membrane filtration method for the sterility test of ophthalmic ointments. Isopropyl myristate, a fatty acid ester that exhibits high toxicity mainly against Gram-negative microorganisms, is indicated as a solvent for ointments. In this study, six fatty acid esters (diethyl adipate, diisopropyl adipate, ethyl laurate, ethyl myristate, methyl caprylate and isopropyl palmitate) were evaluated as solvents to replace isopropyl myristate in the sterility test for ophthalmic ointments. The logarithm of the partition coefficient (logP) of the fatty acid esters was calculated from the sum of the substituent hydrophobicity constants (pi) of the functional groups present in their molecules. The ability of the solvents to dissolve an ophthalmic ointment base was investigated. The D-value method was used to assess the antimicrobial activity of isopropyl palmitate, ethyl myristate, ethyl laurate and isopropyl myristate against Pseudomonas aeruginosa. Isopropyl palmitate was the least toxic solvent to this microorganism, since it had the highest D-value (171.1 min). No significant difference was observed between the D-values of ethyl myristate (89.4 min) and isopropyl myristate (92.5 min). Ethyl laurate exhibited the lowest D-value (27.2 min). Using gas chromatography coupled to mass spectrometry, other fatty acid esters were detected as the predominant impurities in the solvents, as well as acid contaminants in low or insignificant amounts.

Drug Compounding↗
PubMed2005

An anti-inflammatory and antioxidant nutritional supplement for hypoalbuminemic hemodialysis patients: a pilot/feasibility study.

BACKGROUND: A low serum albumin concentration < 3.8 g/dL, a marker of malnutrition-inflammation complex syndrome, is observed in approximately half of all maintenance hemodialysis (MHD) patients in the United States and is strongly associated with increased mortality. OBJECTIVES: We hypothesized that a novel oral nutritional intervention with anti-inflammatory and antioxidant properties taken during routine dialysis sessions is well tolerated and corrects hypoalbuminemia in MHD patients. DESIGN: Controlled clinical study. SETTING: An outpatient dialysis facility affiliated with a tertiary care community medical center with six equally distributed hemodialysis shifts and 163 MHD patients. PATIENTS: Among all MHD outpatients of three selected HD shifts (n = 81 patients), 21 subjects had a serum albumin level < 3.8 g/dL. One patient who was hospitalized before the intervention was excluded. The other three dialysis shifts, with 82 MHD outpatients including 20 hypoalbuminemic subjects, were observed as concurrent controls. INTERVENTION: The nutritional intervention included one can of Oxepa and one can of Nepro to be taken together orally during each routine hemodialysis session for 4 weeks. Each can contains 237 mL fluid. Oxepa provides 355 calories and 14.8 g protein per can, includes maltodextrin, medium-chain triglycerides, borage oil, and refined and deodorized fish oil, and is designed for critically ill patients with inflammation and oxidative stress. Each can of Oxepa includes 1,020 mg gamma-linolenic acid, 3,100 mg caprylic acid, 1,080 mg eicosapentaenoic acid, 75 mg taurine, 2,840 IU vitamin A activity, 75 IU vitamin E, and 200 mg vitamin C. Nepro provides 475 calories and 16.7 g protein per can; includes high-oleic safflower oil, corn syrup solids, and fructo-oligosaccharides; and is tailored for the nutritional needs of MHD patients. Oxepa and Nepro also contain L-carnitine, 43 mg and 62 mg, respectively. MAIN OUTCOME MEASURES: Serum albumin pretrial and posttrial. RESULTS: Studied outpatients (12 men and 8 women) were aged 60.4 +/- 13.0 (SD) years. Three patients had started MHD treatment between 1.5 and 3 months before the intervention. Nine patients were diabetic. Preintervention serum albumin, 3.44 +/- 0.34 g/dL (mean +/- SD) increased to 3.68 +/- 0.34 g/dL (P = .001) 4 weeks after the start of the intervention. In 16 patients, serum albumin level increased by 0.2 to 1.3 g/dL, whereas in 4 patients the serum albumin level decreased by 0.2 to 0.6 g/dL. Three patients reported diarrhea, and one diabetic patient had increased serum glucose values. No other side effects were noted. In 20 control outpatients not receiving nutritional intervention, serum albumin did not change from 3.46 +/- 0.20 to 3.47 +/- 10.44 g/dL (P = .47). CONCLUSIONS: In hypoalbuminemic MHD patients, a short-term in-center nutritional intervention with one can of Nepro and one can of Oxepa during HD is practical, convenient, well-tolerated, and associated with a significant increase in serum albumin level. Well-designed randomized placebo-controlled clinical trials are needed to verify the safety and effectiveness of this nutritional intervention and its impact on clinical outcome in hypoalbuminemic MHD patients.

Aged↗
PubMed2005

Efficient production, purification, and application of egg yolk antibodies against human HLA-A*0201 heavy chain and light chain (beta2m).

The importance of eggs as a source of specific antibodies is well recognized. Egg yolk contains 8--20mg immunoglobulins (IgY) per milliliter. However, the major problem in separating IgY is to remove the high concentrations of lipids in egg yolk. We first used water dilution method to get the supernatant containing IgY, then purified the antibody by caprylic acid-ammonium sulfate method, and obtained specific antibody with satisfactory purity and activity. By comparison of these several methods, each has its advantages, one can be chosen to purify IgY according to practical need. The purified IgY produced by the immunized chickens can stain the human peripheral blood mononuclear cell effectively when labeled with fluorescent FITC.

Animals↗
PubMed2005

Pharmacokinetics, toxicity of nasal cilia and immunomodulating effects in Sprague-Dawley rats following intranasal delivery of thymopentin with or without absorption enhancers.

Thymopentin (TP 5), a synthetic pentapeptide, has been used in clinic as a modulator for immnuodeficiencies through intramuscular administration. The objectives of this study was to investigate the pharmacokinetics using normal rats and toxicity of nasal cilia as well as immunomodulating effects using immunosuppression rats after intranasal delivery of thymopentin with or without an absorption enhancer. The absorption extent of fluorescein isothiocyanate (FITC) labeled TP 5 via nasal delivery at a single dose is significantly improved by incorporating sodium deoxycholate, Brij 35 and chitosan, respectively. FITC-TP 5 can also be absorbed to such an extent ranging from 15 to 28% after intranasal administration of FITC-TP 5 alone, FITC-TP 5 with sodium caprylate, or with bacitracin, respectively. After seven consecutive days multiple dosing, TP 5 formulation with sodium deoxycholate or Brij 35 caused apparently injury to nasal cilia, indicating these two enhancers would not be appropriate for nasal delivery. Results from superoxide dismutase activity, maleic dialdehyde, T-lymphocyte subsets (CD3+, CD4+, CD8+ and CD4+/CD8+ ratio) analyses suggest that all the selected enhancers improve the modulating effects of TP 5 in the immunosuppression rats. On an overall evaluation, intranasal TP 5 alone, TP 5 with chitosan, or TP 5 with bacitracin formulation may be suitable for the future clinical application.

Absorption↗
PubMed1997

Effects of varying the type of saturated fatty acid in the rat diet upon serum lipid levels and spleen lymphocyte functions.

To obtain further information about the effects of specific dietary saturated fatty acids, weanling male rats were fed for 6 weeks on low fat (7.7% by weight) or high fat (17.8% by weight) diets which differed according to the principal fatty acids present. The diets were rich in caprylic and capric acids (medium chain triacylglycerols; MCT), lauric acid, palmitic acid at the sn-1(3) position, palmitic acid at the sn-2 position or stearic acid. The total proportions of saturated (42-46%), monounsaturated (36%), n-6 polyunsaturated (15%) and n-3 polyunsaturated (2.2%) fatty acids were the same in all diets. Serum cholesterol concentrations were not different among rats fed the different diets, except that the concentration in the serum of rats fed the high fat diet with palmitic acid in the sn-2 position was high. This was reflected in higher HDL and LDL cholesterol concentrations in the serum of animals fed this diet. Triacylglycerol (TAG) concentrations tended to be higher in the serum of rats fed the low fat diets compared with those fed the high fat diets. They were lowest in the serum of MCT-fed rats irrespective of the level of fat in the diet and were highest in the serum of rats fed the low fat diet rich in stearic acid. These differences were due to lower chylomicron and VLDL TAG concentrations in the serum of MCT-fed rats and higher chylomicron and VLDL TAG concentrations in the serum of low fat, stearic acid-fed animals. The fatty acid compositions of the serum and of spleen lymphocytes were influenced by that of the diet fed. The ex vivo proliferation of lymphocytes from the spleens of rats fed the high fat diet rich in palmitic acid at the sn-2 position was greater than that of lymphocytes from animals fed the other diets. Natural killer (NK) cell activity tended to be lower for spleen lymphocytes from rats fed high fat diets than for those fed low fat diets irrespective of the principal saturated fatty acid present. NK cell activity was highest for spleen lymphocytes from animals fed the diets rich in palmitic acid and was lowest for those from animals fed the high fat diet rich in stearic acid. Spleen lymphocytes from the latter animals had the lowest proportion of CD16+ cells, a marker for NK cells. Thus, this study shows that the type of saturated fatty acid present in the diet not only has subtle effects upon blood lipid and lipoprotein levels but can significantly affect lymphocyte functions. Spleen lymphocyte NK cell activity is decreased as the fat content of the diet increases. NK cell number and activity are reduced by a high fat diet rich in stearic acid. Spleen lymphocyte proliferation is enhanced by palmitic acid-rich diets, particularly if palmitic acid is in the sn-2 position of dietary TAG.

Animals↗
PubMed1995

Interdigitation does not affect translational diffusion of lipids in liquid crystalline bilayers.

Asymmetric phosphatidylcholine molecules with one acyl chain twice as long as the other, below their phase transition temperature, from a mixed interdigitated phase in which the longer acyl chain spans the entire bilayer. Experimental evidence in the literature suggests that, above their phase transition temperature, these molecules may still exhibit partial interdigitation, with the longer acyl chain extending partially into the opposite leaflet, and are packed more tightly than equivalent symmetric phosphatidylcholines. Using the fluorescence recovery after photobleaching technique, we have investigated the translational diffusion in multilayers of a liquid crystalline phase, asymmetric phosphatidylcholine, 1-stearoyl-2-capryl-phosphatidylcholine (C18C10PC). We used as a fluorescent probe either a phospholipid analog of the same acyl chain composition, NBD-C18C10PE, or the symmetric equivalent of the same molecular weight, N-(7-nitrobenzoxa-2,3-diazol-4-yl)-dimyristoyl-phosphatidyle thanolamine (NBD-DMPE). Translational diffusion coefficients were also determined by using both probes in multilayers of dimyristoyl-phosphatidylcholine (DMPC) and in the eutectic mixture DMPC/C18C10PC (40/60 mol). We found that in a given host lipid, NBD-C18C10PE and NBD-DMPE diffuse at the same rate, which suggests that their bilayer free area is almost identical. This result can be explained by considering that in the liquid crystalline state, the increase in molecular packing is compensated by an increase in acyl chain dynamics. This view, which is supported by literature data, clearly suggests that the acyl chain interdigitation occurring in the liquid crystalline phase is highly dynamic.

4-Chloro-7-nitrobenzofurazan↗
PubMed2002

The antimicrobial properties of milkfat after partial hydrolysis by calf pregastric lipase.

Studies on the kinetic characteristics of calf pregastric lipase (EC 3.1.1.3) have shown that it preferentially releases short chain fatty acids (SCFAs) from bovine milkfat. The released fatty acids form mixed micelle structures. The aim of this investigation has been to test whether hydrolysed milkfat is antimicrobial, and how the state of the emulsion alters the bactericidal or bacteriostatic effects. Partial hydrolysis of milkfat by pregastric lipase was carried out in two types of emulsion systems, containing either Triton X-100 or casein/lecithin, plus milkfat in citrate/phosphate buffer (pH 5.0-6.0). The concentrations and compositions of fatty acids were determined by gas chromatography. The minimum percentages of hydrolysed milkfat which affected growth and survival of selected Gram-positive and Gram-negative bacteria were measured. The bacterial experiments were repeated using pure fatty acids at similar concentrations. Lauric acid (C12:0) was found to be the most potent bactericidal fatty acid against Enterococcae (Gram-positive), and caprylic acid (C8:0) was the most potent against coliforms (Gram-negative). Use of Triton X-100 for milkfat emulsification provided a more compatible medium for studying bacterial growth in the hydrolysed milkfat than did use of casein/lecithin. The results also show that the antimicrobial effects of individual fatty acids released from hydrolysed milkfat were at least additive and suggest that hydrolysis of milkfat may be a significant factor in controlling growth of organisms imbibed with food in pre-weaned animals. The amount of pregastric catalyzed triglyceride hydrolysis in the digestive tract is sufficient to produce an antibacterial concentration of fatty acids and monoglycerides.

Animals↗
PubMed1998

Making vitamin C lipophilic enhances its protective effect against free radical induced peroxidation of low density lipoprotein.

The peroxidation of human low density lipoprotein (LDL) was initiated by water-soluble initiator 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH) and copper and inhibited by vitamin C (VC) and its lipophillic derivatives ascorbyl-6-caprylate (VC-8), 6-laurate (VC-12) and 6-palmitate (VC-16), respectively. The peroxidation was monitored by oxygen uptake, by decay of alpha-tocopherol and by formation of lipid oxidation products. Kinetic analysis of the antioxidation process demonstrates that the VCs can work synergistically with endogenous antioxidants (vitamin E, ubiquinol-10, beta-carotene etc.) in LDL to suppress the peroxidation and that the synergistic effect of the lipophilic VCs is appreciably higher than that of their lipophobic parent molecule. It is also shown that VC and especially the lipophilic VCs, are much more effective in inhibition of copper-induced than AAPH-induced LDL peroxidation.

Amidines↗
PubMed2001

Application of zirconium-modified silica gel as a stationary phase in the ion-exclusion chromatography of carboxylic acids. II. Separation of aliphatic carboxylic acids with pyromellitic acid as eluent and with suppressed conductimetric detection.

The application of zirconium-modified silica gels (Zr-Silica) as stationary phases for ion-exclusion chromatography with conductimetric detection (IEC-CD) for C1-C8 aliphatic carboxylic acids (formic, acetic, propionic, butyric, valeric, caproic, heptanoic and caprylic acids) was carried out using pyromellitic acid as the eluent. Zr-Silicas were prepared by the reaction of the silanol group on the surface of silica gel with zirconium tetrabutoxide [Zr(OCH2CH2CH2CH3)4] in ethanol solution. An ASRS-Ultra anion self-regenerating suppressor in the K+ form was used for the enhancement of conductimetric detector response of these aliphatic carboxylic acids. A Zr-Silica adsorbed on 10 mg zirconium g(-1) silica gel was the most suitable stationary phase in IEC-CD for the separation of these aliphatic carboxylic acids. Excellent simultaneous separation and highly sensitive detection for these aliphatic carboxylic acids were achieved in 25 min by IEC-CD with the Zr-Silica column (250x4.6 mm I.D.) and a 0.2 mM pyromellitic acid containing 0.15% heptanol as the eluent.

Benzoates↗
PubMed2003

Effects of oral stimulation with fats on the cephalic phase of pancreatic enzyme secretion in esophagostomized rats.

Recent studies suggest that there is a chemical perception of dietary fat in the oral cavity. A much greater response in the cephalic phase of pancreatic secretion is obtained by palatable taste stimuli. To examine the perception of dietary fat in the oral cavity, we determined whether or not oral stimulation with fat alters the cephalic phase of pancreatic enzyme secretion. A cannula was inserted into the common bile duct of rats to collect bile-pancreatic juice, and the animals were esophagostomized to prevent stimulation of the gastrointestinal tract with the test substances. The cephalic phase of pancreatic enzyme secretion was enhanced by oral stimulation with the long chain fatty acids, oleic acid, linoleic acid and linolenic acid, but was unaffected by the middle chain fatty acid, caprylic acid, and long chain fatty acid derivatives, methyl oleate and methyl linoleate. This selectivity is consistent with our previous findings that, in a short term two-bottle preference test, rats prefer long chain fatty acids to triglycerides, middle chain fatty acids or long chain fatty acid derivatives. These results suggest that long chain fatty acids trigger chemical reception in the oral cavity, and the length of the fatty acid chain and the presence or absence of carboxylate groups are related to recognition of fat.

Animals↗
PubMed2003

Report of a WHO workshop on the standardization and control of antivenoms.

A workshop to discuss progress in the standardization and control of antivenoms, organized by the Quality Assurance and Safety of Biologicals Unit of WHO, was held at the National Institute for Biological Standards and Control, Potters Bar, England, 7-9 February 2001. This was the first meeting convened by the WHO on this subject since 1979 and it brought together experts from academic institutions, antivenom manufacturers and national regulatory authorities from 21 countries. The meeting reviewed antivenom production and quality control measures and special consideration was given to the current crisis in antivenom production and supply in sub-Saharan Africa. The importance of snake bite and scorpion stings as public health issues was re-emphasised. The majority of commercial antivenoms are raised against snake or scorpion venoms.The review of antivenom production methods indicated that the vast majority of commercial antivenoms were still produced by traditional technology in horses, although some antisera were raised in sheep and rabbits. Methods used for plasma fractionation included salt and heat coagulation, caprylic acid stabilization or ion exchange chromatography, as well as immunoglobulin digestion with pepsin to produce F(ab')(2) or with papain to produce Fab fragments. The meeting agreed that there was much room for improving the production, quality control and safety profile of these products and that lessons could be learnt from the experience gained with the preparation of human immunoglobulins. Many basic assumptions, such as the need to remove Fc fragments by enzyme digestion and to freeze-dry antivenom preparations, required critical re-examination and more attention should be given to clinical trials as a means of assessing efficacy and safety and of defining the average initial dose. The Workshop also discussed concerns about the risks of transmitting infectious agents to humans via animal blood products, especially those posed by viruses or prions and it was agreed that this aspect needed attention. However, there was no documented or even suspected example of this ever having occurred in the case of antivenom treatment. Current WHO Requirements for the production and control of antivenoms and for immune sera of animal origin date from the late 1960s. The Workshop recommended that these be updated to take account of the progress that had taken place in the production and quality control of biologicals in recent years. In addition, the Workshop discussed the need for better standardization of both the venoms and antivenoms, but concluded that international standards and reference materials were not appropriate in the antivenom field due to the considerable variation in venom characteristics from the same species from region to region. Instead, it was recommended that national or regional standards be prepared and used.

Animals↗
PubMed2000

Lysophosphatidylcholine synthesis with Candida antarctica lipase B (Novozym 435).

Immobilized lipase from Candida antarctica lipase B (Novozym 435) was effective in the synthesis of lysophosphatidylcholine (LPC). The transesterification of L-alpha-glycerophosphorylcholine (GPC) and vinyl laurate was carried out in a solvent free system or in the presence of 50% (v/v) t95%) were easily achieved. The lipase was selective for the sn10 times). High purity products could be produced by a decrease of the reaction temperature to induce precipitation of the product. The temperature needed depended on the fatty acid chain length. Thus, only lysophosphatidylcholine was produced with palmitic acid vinyl ester at 45 degrees C, whereas for the vinyl esters of lauric acid, capric acid, and caprylic acid, a lower reaction temperature (25 degrees C) was necessary to obtain solely the lysophospholipid products.

Journal Article↗
PubMed2000

Mycelium-bound carboxylesterase from Aspergillus oryzae: an efficient catalyst for acetylation in organic solvent.

Dry mycelium of a strain of Aspergillus oryzae efficiently catalyzed the esterification between free acetic acid and primary alcohols (geraniol and ethanol) in organic solvent. The growth conditions to obtain high activity of mycelium-bound enzymes were firstly evaluated. A medium containing Tween 80 as carbon source furnished mycelium with the highest activity in the hydrolysis of alpha-naphthyl esters (alpha-N-acetate, butyrate, caprylate). Dry mycelium was employed to select suited conditions for an efficient acetylation of ethanol and geraniol in heptane. Maximum productions were obtained using 30 g l(-)(1) of lyophilized cells: 12.4 g l(-)(1) of geranyl acetate were produced at 80 degrees C starting from 75 mM geraniol and acetic acid (84% molar conversion) and 4.1 g l(-)(1) of ethyl acetate at 50 degrees C from 50 mM ethanol and acetic acid (94% molar conversion) after 24 h. The stability of the mycelium-bound carboxylesterases are notable since only 10-30% loss of activity was observed after 14 days at temperatures between 30 and 50 degrees C.

Journal Article↗
PubMed2002

Measurement of serum immunoglobulin concentration in killer whales and sea otters by radial immunodiffusion.

Killer whales and sea otters maintained in captivity are the subjects of routine health monitoring programs, and interest in immunologic studies in sea otters has been rising recently in response to potential impacts from infectious disease and environmental pollution on the threatened southern sea otter population. Development of species-specific reagents for immunologic studies in these two marine mammals is currently in its infancy. In this study, killer whale and sea otter immunoglobulin-specific polyclonal antibodies were generated, and used to develop tests for serum Ig concentration in the killer whale (Orcinus orca) and the southern (Enhydra lutris nereis) and northern sea otter (Enhydra lutris lutris). Killer whale serum IgG was purified using caprylic acid/ammonium sulfate precipitation. Sea otter plasma IgG was purified using protein-A-agarose. Polyclonal anti-Ig antisera were produced in rabbits, and specificity confirmed by immunoelectrophoresis. Radial immunodiffusion was used to measure Ig concentration in serum or plasma samples derived from 21 captive killer whales, 18 wild and 4 captive southern sea otters and 15 wild and 4 captive northern sea otters grouped by age. Mean killer whale serum Ig concentration (+/-95% confidence interval) ranged from 15.04 +/- 3.97 g/l for animals aged 0-5 years to 26.65 +/- 9.8 g/l for animals aged >10 years. Mean sea otter serum Ig concentration (+/-95% confidence interval) ranged from 28.39 +/- 11.00 g/l for southern sub-adults to 32.76 +/- 11.58 g/l for southern adults. No significant difference in serum Ig concentration was found between southern and northern sea otters. Serum Ig concentrations in two northern sea otter pups were low compared to those of adult sea otters. The two serum Ig quantitation assays produced were highly specific and reproducible and will be useful additions to the limited number of tests available for immune function in these marine mammal species.

Animals↗