Levels Of Acid Phosphatase Activity Research Articles

Acid phosphatase and cathepsin activity in cuttlefish (Sepia officinalis) eggs: the effects of Ag, Cd, and Cu exposure

AbstractLacoue-Labarthe, T., Le Bihan, E., Borg, D., Koueta, N., and Bustamante, P. 2010. Acid phosphatase and cathepsin activity in cuttlefish (Sepia officinalis) eggs: the effects of Ag, Cd, and Cu exposure. – ICES Journal of Marine Science, 67: 1517–1523. Changes in the activity levels of acid phosphatase (AcP) and cathepsin during cuttlefish embryo development are described, as are the effects of exposure to heavy metals. Enzyme activity kinetics appear to be linked to the developmental stage. The activities of both enzymes increased during the final days of development, suggesting de novo production by the maturing embryo in the digestive gland. The effects of selected heavy metals, Ag (0.06, 1.2, 60, 1200 ng l−1), Cd (31, 61, 305, 610 ng l−1), and Cu (0.23, 2.3, 23, 230 µg l−1), were assessed based on AcP and cathepsin activities at the end of embryonic development and on hatchling weight. Enzyme activities were not impacted by Ag but were significantly inhibited by Cd, at all four concentrations for AcP and at 610 ng l−1 for cathepsin. Cu (at 2.3 µg l−1) stimulated AcP activity. No cause–effect relationship was found between the effects of metals on the enzyme activities and hatchling weight, suggesting that heavy metals could affect other physiological functions during embryogenesis.

Molecular cloning and characterization of acid phosphatase in venom of the endoparasitoid wasp Pteromalus puparum (Hymenoptera: Pteromalidae)

The present study describes cDNA cloning, sequencing, enzyme activity determination and localization, and mRNA expression of acid phosphatase in the venom apparatus of an endoparasitoid, Pteromalus puparum. This is the first report of cloning a venom acid phosphatase gene which has been described in parasitoid wasps. The cDNA consisted of 1378 bp with 1215 bp open reading frame and encoded a sequence of 405 amino acids. A 23 residues N-terminal signal peptide was followed by a short 15 residues (25–39) histidine acid phosphatases phosphohistidine signature and a long 302 residues (24–325) acid phosphatase family domain. The deduced amino acid sequence shared 32–88% identity to its counterparts from other insects. Enzyme activity was measured by using p-nitrophenyl phosphate ( p-NPP) as substrate, and a high level of acid phosphatase activity in venom was detected. Optimal pH and temperature for this enzyme activity was 4.8 and 45 °C, respectively. Ultracytochemical analyses further revealed that strong enzyme activity was located in the nuclei and secretory vesicles of the venom gland secretory cells. Expression of the acid phosphatase gene was observed to be regulated at different developmental stages by RT-PCR analysis as it expressed immediately with low abundance after adult emergence, then increased to the high level at 2–4 days, followed by a drop to the low abundance after 4 days. Compared to the mRNA expression, a time-course-related enzyme activity in an individual venom apparatus was also found.

Assessment of Exfoliated Prostate Cells in Semen

The percentage of exfoliated prostate cells (EPCs) in 139 semen specimens was determined. A receiver operating characteristic curve showed a cutoff of 17% for EPCs, and specimens were distributed into 4 groups: EPCs 17% or fewer without (group 1; n=44) and with (group 2; n=31) leukocytospermia and EPCs more than 17% without (group 3; n=39) and with (group 4; n=25) leukocytospermia. Acid phosphatase, calcium, and zinc levels; volume and pH of ejaculate; and leukocyte count were assessed. Between groups 1 and 2, the only significant difference was in leukocyte count (P<.001). Between groups 3 and 4, differences were significant in zinc levels (P=.026) and leukocyte count (P<.001). Comparisons of groups 1 and 2 vs 3 and 4 showed lower levels of acid phosphatase activity (P=.017) and calcium (P=.019), and increased seminal volume (P=.019) between groups 1 and 3. Between groups 2 and 4, the difference was significant only in leukocyte count (P<.001). EPCs of 17% or fewer with and without leukocytospermia suggest normal prostate function; EPCs of more than 17% without leukocytospermia suggest abnormal function. EPCs of more than 17% with leukocytospermia were inconclusive.

Functional significance of dauciform roots: exudation of carboxylates and acid phosphatase under phosphorus deficiency in Caustis blakei (Cyperaceae)

Caustis blakei produces an intriguing morphological adaptation by inducing dauciform roots in response to phosphorus (P) deficiency. We tested the hypothesis that these hairy, swollen lateral roots play a similar role to cluster roots in the exudation of organic chelators and ectoenzymes known to aid the chemical mobilization of sparingly available soil nutrients, such as P. Dauciform-root development and exudate composition (carboxylates and acid phosphatase activity) were analysed in C. blakei plants grown in nutrient solution under P-starved conditions. The distribution of dauciform roots in the field was determined in relation to soil profile depth and matrix. The percentage of dauciform roots of the entire root mass was greatest at the lowest P concentration ([P]) in solution, and was suppressed with increasing solution [P], while in the field dauciform roots were predominantely located in the upper soil horizons, and decreased with increasing soil depth. Citrate was the major carboxylate released in an exudative burst from mature dauciform roots, which also produced elevated levels of acid phosphatase activity. Malonate was the dominant internal carboxylate present, with the highest concentration in young dauciform roots. The high concentration of carboxylates and phosphatases released from dauciform roots, combined with their prolific distribution in the organic surface layer of nutrient-impoverished soils, provides an ecophysiological advantage for enhancing nutrient acquisition.

Biochemical characteristics and sperm production of turkey semen in relation to strain and age of the males

The effect of turkey strain [BUT (Big-6), Hybrid Large White (HLW), and Nicholas (N-700)] on semen quantitative parameters (ejaculate volume, sperm concentration, and total number of sperm) and biochemical parameters (seminal plasma protein concentration, acid phosphatase activity in spermatozoa and seminal plasma, and antiproteinase activity of seminal plasma) was investigated over the reproductive period. The Big-6 strain had better quantitative parameters of semen compared with HLW and N-700 strains. Besides protein concentration, the Big-6 strain had the highest level of acid phosphatase activity in semen and antiproteinase activity in seminal plasma. The N-700 strain was characterized by reduced quantitative parameters and the lowest levels of all biochemical parameters in semen. While quantitative parameters of semen showed very little trend over the 21 wk of the reproductive season, the biochemical parameters increased several fold. Biochemical parameters of semen seemed to be more affected than quantitative parameters by age of the males. These changes may be related to decreasing semen quality with increasing age of male turkeys.

Hydrolase activity in the venom of the pupal endoparasitic wasp, Pimpla hypochondriaca

Venom from the pupal endoparasitoid, Pimpla hypochondriaca has previously been shown to contain a mixture of biologically active molecules. Currently, P. hypochondriaca venom was examined for the presence of hydrolase activity. Six hydrolases were consistently detected using the API ZYM semiquantitative colourimetric kit. The main hydrolases detected were; acid phosphatase, β-glucosidase, esterase, β-galactosidase, esterase lipase, and lipase. The most rapid and intense colour reaction was detected for acid phosphatase. The pH optimum and the specific activity of venom acid phosphatase was determined using p-nitrophenol phosphate as a substrate and were 4.8 and 0.47 nmol p-nitrophenol/min/μg of venom protein, respectively. The acid phosphatase activity was inhibited in a dose dependent manner by sodium fluoride (IC 50 4.2 × 10 − 4 M), and by cocktail inhibitor 2 (CI 2). P. hypochondriaca venom has previously been shown to display potent cytotoxic activity towards Lacanobia oleracea haemocytes maintained in vitro. The contribution of acid phosphatase in venom to this cytotoxic activity was investigated by titrating venom against CI 2 prior to the addition of L. oleracea haemocytes. The results suggest that, despite the relatively high levels of acid phosphatase activity in venom, venom acid phosphatase plays no role in the antihaemocytic activity of P. hypochondriaca venom in vitro.

Fosfatases na dinâmica do fósforo do solo sob culturas de cobertura com espécies micorrízicas e não micorrízicas

O objetivo deste trabalho foi avaliar, mediante a atividade de fosfatases no solo, o efeito de plantas de cobertura micorrízicas e não micorrízicas nos aspectos biológicos da dinâmica do fósforo em sistemas sob plantio direto. Solos sob espécies não micorrízicas apresentaram maior atividade de fosfatases ácidas e alcalinas no estádio de floração, e os níveis de atividade de fosfatases ácidas persistiram nos cultivos subseqüentes ao crescimento das culturas de cobertura. A maior atividade enzimática, relacionada à mineralização de fosfatos orgânicos, em solos com espécies não micorrízicas pode ser um mecanismo de aumento da mobilização do fósforo no solo, compensando a ausência de micorrizas.

Biomassa microbiana e atividade enzimática em solos sob vegetação nativa e sistemas agrícolas anuais e perenes na região de Primavera do Leste (MT)

Primavera do Leste é um dos pólos de produção de grãos e fibras do Mato Grosso, com lavouras altamente tecnificadas. Este estudo foi realizado num Latossolo Vermelho-Amarelo da região de Primavera, com objetivo de avaliar a biomassa e a atividade microbiana de solos sob vegetação nativa e sistemas agrícolas anuais e perenes. As amostras de solo foram coletadas em duas profundidades (0-5 e 5-20 cm), no início da estação chuvosa, em áreas sob cultivo de videira (Vitis vinifera), entrelinha e linha, cultivos anuais (soja) e em uma área de vegetação nativa de Cerradão. Foram avaliados o carbono da biomassa microbiana (CBM), carbono prontamente mineralizável e as atividades das enzimas beta-glucosidase, fosfatase ácida e arilsulfatase. Nas duas profundidades avaliadas, os sistemas de uso do solo com culturas perenes e anuais apresentaram reduções médias de 70 % no CBM, em relação à área sob vegetação nativa. O manejo diferenciado na entrelinha do parreiral e a utilização do capim-pé-de-galinha (Eleusine indica), como cobertura viva, proporcionaram aumentos no C mineralizável e na atividade das enzimas beta-glucosidase e arilsulfatase nas duas profundidades. Os níveis médios de P no solo sob Cerradão resultaram em valores de atividade da fosfatase ácida inferiores aos dos observados em outros locais do Cerrado. Mesmo assim, na profundidade de 0-5 cm, a atividade da fosfatase ácida no Cerradão foi superior à da entrelinha do parreiral (VE) e à da área com culturas anuais, demonstrando a sua importância na mineralização do fósforo orgânico em áreas sob vegetação nativa. Os resultados obtidos confirmaram a sensibilidade dos parâmetros microbiológicos e bioquímicos para identificar alterações no solo de acordo com os diferentes sistemas de uso da terra.

Effect of culture conditions on the biosynthesis of Aspergillus niger phytase and acid phosphatase

The reduction of phytate content in plant feeds is advisable for increasing of their nutritional values. The dephosphorylation of phytates is believed to be mainly effected by phytase. A strain of Aspergillus niger shows a high potential for phytase production. In this study the possibilities to increase the enzyme production by alteration of the growth conditions of Aspergillus niger 307 are investigated. The effect of the type, age and quantity of the inoculum was established. The strain showed maximal productivity when about 50-day-old spores were used as inoculum and the augmentation of phytase and acid phosphatase activities was 3.29-fold and 2.17-fold, respectively. Two-fold increase of the phytase activity was observed when the inorganic phosphorus concentration in the media was 10 mg%. The highest level of acid phosphatase activity was produced at 17.5 mg% P i. The unpurified phytase from Aspergillus niger 307 shows two pH optima—at 2.5 and 5.0 and temperature optimum ( T opt) is 56 and 58 °C, respectively. The pH optimum for acid phosphatase action is 2.1 and T opt is 73 °C.

Variations in levels of acid phosphatase present in chicken whole leg meat

Acid phosphatase (ACP) has been identified as a potential biomarker for endpoint temperature determination in further-processed poultry. Multiple analyses of the same sample for ACP have produced consistent results. The degree of variation in ACP levels present in different production lots has not been identified. This study was conducted utilizing a single flock of broilers. Birds were slaughtered on four separate days (replications), and whole leg, without skin, was homogenized. Proximate composition was analyzed for each replication. Water-soluble proteins were extracted from raw meat and assessed for initial ACP levels. Samples of meat were cooked to an internal temperature of 71.1 C. There were differences (P < 0.05) between replications for both moisture and fat content. When dry fat content was analyzed, no significant differences occurred between replicates. Initial ACP levels were different (P < 0.0001) between replicates (500.33 to 348.97 units of activity/kg). Levels of ACP activity after cooking were also different (P < 0.0001) between replicates (17.61 to 10.82 units of activity/kg). Percentage degradation of activity during cooking was similar (96.98 to 95.89%) between replicates. ACP levels were consistently measured within a replicate. Differences between replicates for both initial and cooked levels indicate a threshold level for determination of thermal endpoint would be difficult to establish. ACP may not be a sensitive measure to estimate the degree of doneness of meat samples in which initial ACP concentration is unknown. Identical raw sample required for such a comparison would be difficult for the processing industry to maintain.

Effect of section of yam (Dioscorea cayenensis) tuber used in minisett on the biochemical properties of the resultant tuber

AbstractThe effect of the section of yam (Dioscorea cayenensis) tuber used as planting material in minisett on the biochemical properties of the resultant tuber was studied. The biochemical parameters invertase (EC 3.2.1.26), acid phosphatase (EC 3.1.3.2), peroxidase (EC1.11.1.7), polyphenol oxidase (EC 1.10.3.1), total sugars and starch were evaluated in tubers resulting from field‐grown and tissue culture‐derived setts of the cultivars Roundleaf and Blackwiss yellow yams. No significant differences were observed between tubers resulting from field‐grown and tissue culture‐derived setts relative to the parameters studied. Invertase activity was found to be highest in tubers from middle‐derived setts, while tail‐derived setts had the lowest activity for both cultivars. Middle‐derived tubers were also found to have significantly higher levels of acid phosphatase activity and starch content. However, middle‐derived tubers had the lowest level of total sugars. Polyphenol oxidase and peroxidase were also found to be significantly higher in tubers from middle‐derived setts. These results suggest a higher rate of active starch formation in tubers from middle‐derived setts.© 2002 Society of Chemical Industry

Acid phosphatase activity in excretion/secretion products from Heligmosomoides polygyrus adults: an indicator of the physiological status of the worms.

Acid phosphatase (AP) activity was detected in 24 h culture media from adult Heligmosomoides polygyrus. Female and male excretion/secretion products showed similar specific activity. For both, the AP had a pH optimum of 4.0 and was inhibited by sodium fluoride, tartaric acid, and sodium orthovanadate. The release of AP by adult worms was significantly inhibited by adverse incubation conditions (temperatures of 20 degrees C and 4 degrees C), known physiological perturbers ( t-butylhydroperoxide and sodium azide), and broad spectrum anthelmintics (albendazole, levamisole, morantel, and ivermectin). These results indicate that the AP activity level in the culture medium may be an indicator of the physiological status of the worms.

Altered bone turnover in chlorpromazine-challenged rats and its effect on 1alpha-hydroxyvitamin D3 administration in vivo.

We reported previously that Ca and Pi levels are elevated and alkaline phosphatase (ALP) activity and 1alpha,25(OH)2D3 levels are reduced in chlorpromazine (CPZ)-challenged rats. In the present study, we determined the serum levels of interleukin (IL)-6 and acid phosphatase (ACP) in CPZ-challenged rats, in addition to levels of ALP protein. ALP mRNA and coccyx morphology were examined in CPZ-challenged rats as well as the effect of CPZ on 1alpha(OH)D3 production in vivo. Although Ca, Pi, IL-6, and ACP activity levels in CPZ-challenged rats were markedly increased on day 30, the elevated serum levels were restored to within normal ranges by the in vivo addition of 1alpha(OH)D3 to CPZ administration. The gain in body weight in CPZ-treated rats was significantly improved by the addition of 1alpha(OH)D3. Reduced levels of 1alpha,25(OH)2D3 in CPZ-treated rats were restored to normal levels by the administration of 1alpha(OH)D3. Moreover, the decreased ALP activity and ALP mRNA levels in the rat coccyx marrow in CPZ-treated rats were also restored by the administration of 1alpha(OH)D3 with CPZ. However, the molecular sizes of rat ALP molecules and ALP mRNA were the same for each group. Furthermore, bone morphometry showed that trabecular bone in the rat coccyx was decreased in CPZ-treated rats. However, the reduced volume of trabecular bone in CPZ-treated rats was restored by the addition of 1alpha(OH)D3 to CPZ administration. Taken together, altered bone metabolism in CPZ-treated rats can be improved by the addition of 1alpha(OH)D3.

Enzyme histochemical profile of immunohistochemically identified Renshaw cells in rat lumbar spinal cord

Activity levels of cytochrome oxidase, acid phosphatase, and NADPH diaphorase were examined in the perikarya of immunohistochemically identified Renshaw cells from sections of rat lumbar spinal cord. Renshaw cell profiles were identified on the basis of their characteristic anti-gephyrin-immunofluorescent labelling. Intrasomatic densities of enzyme histochemical reaction product were employed as indicators of relative mitochondrial activity (cytochrome oxidase), intracytoplasmic digestion (acid phosphatase), or putative nitrergic signalling (NAPDH-diaphorase). Approximately half of the Renshaw cell somata examined displayed moderate levels of cytochrome oxidase reaction product (142 of 262 Renshaw cells) or low levels of acid phosphatase activity (156 of 243 Renshaw cells). A majority (160 of 202 cells) of Renshaw cells contained low intrasomatic levels of NADPH-diaphorase activity but most of these cells were closely apposed by at least one NADPH-diaphorase reactive axonal varicosity. Our findings suggest that moderate levels of perikaryal oxidative metabolism and low levels of intracytoplasmic digestion are sufficient for, and support, the unique physiological capabilities of Renshaw cells. The presence of NADPH-diaphorase containing somatic close contacts indicate that nitric oxide may have at least a minor role in the regulation of Renshaw cell activity. These results are complementary and consistent with previous morphological and pharmacological demonstrations of Renshaw cell heterogeneity.

Correction of Defective Host Response to Mycobacterium Bovis BCG Infection in TNF-Deficient Mice by Bone Marrow Transplantation

Tumour necrosis factor-α (TNF) plays a central role in the recruitment and activation of mononuclear cells in mycobacterial infection. In the absence of type 1 TNF receptor, Mycobacterium bovis Bacillus Calmette–Guérin (BCG) infection of mice is not contained, leading to fatal disease. Because type 1 TNF receptor binds both TNF and lymphotoxin-α, we used TNF-deficient mice to determine the specific role of TNF in the host resistance to BCG infection. The bacterial burden of the lungs of TNF-deficient mice was substantially increased and the mice succumbed to pneumonia between 8 and 12 weeks with a defective granuloma response. Atypical granulomas developed by 4 weeks expressing low levels of MHC class II, intracellular adhesion molecule (ICAM-1), CD11b and CD11c. Macrophages showed little signs of activation and had low levels of acid phosphatase activity and inducible nitric oxide synthase (INOS) expression. Despite the defective cellular recruitment, the chemokines, monocyte chemoattractant protein–1 (MCP-1) and macrophage inflammatory protein–1 (MIP-1α), were increased in broncho-alveolar lavage fluid of TNF-deficient mice. The defective host response was corrected by the transplantation of normal bone marrow cells into irradiated TNF-deficient mice. These results demonstrate that TNF derived from hemopoietic cells rather than from mesenchymal origin are essential for a normal host response to BCG infection. Furthermore, TNF dependent expression of adhesion molecules may be essential for the recruitment of mononuclear cells for the formation of bactericidal BCG granulomas.

Efficacy of Trichoderma reesei phytase and acid phosphatase activity ratios in phytate phosphorus degradation in vitro and in pigs fed maize–soybean meal or barley–soybean meal diets

Efficacy of phytase together with different activity levels of acid phosphatase (AcPh) produced by transgenic strains of Trichoderma reesei in degrading phytates in maize, barley and soybean meal (SBM) was evaluated in vitro and in vivo with growing pigs. There was no interaction between the phytase (1000 PU g −1) and AcPh (7500 HFU g −1) dosage in the hydrolysing of phytates in any ingredients at pH 6.0. AcPh, however, complemented phytate dephosphorylation over that of phytase in barley and maize but not in SBM at pH 2.5, which is the pH optimum of the AcPh used. Barley–SBM and maize–SBM diets (800 : 200 g kg −1) without inorganic P (total P 4.1 g kg −1, available P 1.0 g kg −1) and supplemented with phytase 1100 PU kg −1 together with different activities of AcPh: 500, 4800, 7900 and 19 300 HFU g −1 were fed to growing pigs (36–69 kg live weight) in two 4 × 4 Latin square designed experiments. An increased AcPh level linearly improved ( p < 0.05) the ash digestibility of maize-diets while no effect on other nutrients was found. The gradual increase of the AcPh level linearly improved ( p < 0.05) the apparent absorption of P (3% to 7%-units) in both diets. The retained P in maize–SBM-diets with an increased level of AcPh was significantly improved ( p < 0.05) from 3.5 to 4.0 g day −1 while the response in the barley–SBM-diet was smaller and non-significant. Ca retention increased linearly ( p < 0.05) in maize–SBM-diets while no effect was noticed in barley diets due to the AcPh dosage. The results indicate that the synergistic interaction between microbial phytase and acid phosphatase activity levels is rather limited in degradation of phytates in barley, maize and SBM.

An Arabidopsis mutant missing one acid phosphatase isoform.

Plant response to phosphorus starvation includes the increased production and secretion of acid phosphatase. We have isolated a mutant of Arabidopsis thaliana (L.) Heynh., phosphatase-underproducer 1 (pup1), that has reduced histochemical staining for acid phosphatase activity in roots of plants grown under phosphorus-starvation conditions. Although pup1 is defective in the production of one inducible acid phosphatase isoform, the most abundant inducible isoform is present. The pup1 mutants are able to respond to phosphorus-deficient conditions by an increase in overall levels of acid phosphatase activity, accumulation of anthocyanins, an increase of the root-to-shoot ratio, and changes in the partitioning of phosphorus between roots and shoots. The gross morphology of the mutants appears normal, except that a small difference in the root to shoot ratio was observed in plants grown under nonstressed conditions. The pup1 gene is incompletely dominant and it is located between 40.2 (+/- 6.2) and 44.9 (+/- 9.9) cM on chromosome 2. This mutant will be useful for determining the role of this acid phosphatase isoform in plant response to phosphorus starvation.

Host nuclear abnormalities and depletion of nuclear antigens induced in Trichinella spiralis-infected muscle cells by the anthelmintic mebendazole

Infection by the parasitic nematode Trichinella spiralis induces cell cycle repositioning (chronic suspension in apparent G 2/M) and genetic reprogramming in differentiated mammalian skeletal muscle cells. These changes occur in association with dramatic enlargement of infected host cell nuclei (as large as 17 μm in diameter) and nucleoli. Nuclear antigens (NA) that colocalize with host chromatin have been detected by antibodies to T. spiralis antigens, but the functions of these NA are unresolved. Mebendazole (MBZ) preferentially binds parasite versus host β-tubulins, is implicated in inhibiting secretion in nematodes and induces cytoplasmic changes in muscle cells infected with T. spiralis. These infected cell changes might be indirect via MBZ inhibition of parasite secretions. This effect would have implications for host/parasite interactions and was evaluated here. MBZ treatment of chronically infected mice caused: (1) a significant deformation of host nuclei and diminution of nucleoli by 4 and 6 days of treatment (dot), respectively; (2) a reduction of nuclear lamins A/C in infected cell nuclei that was concomitant with nuclear deformation; and (3) significant reductions in total RNA, general protein and acid phosphatase activity levels. These changes were associated with the depletion of NA from host nuclei detected by 4 dot. However, DNA content of infected cell nuclei was not detectably reduced and muscle gene expression was not reactivated. The cellular changes documented are likely to account for previously described cytoplasmic alterations induced by MBZ. Concomitant depletion of NA from infected cell nuclei suggests a role of these products in regulating nuclear functions of host cells.

Fluorometric Determination of Acid Phosphatase in Cooked, Boneless, Nonbreaded Broiler Breast and Thigh Meat

This method is applicable for determining activity of acid phosphatase (ACP), a heat-labile enzyme, in cooked, boneless, nonbreaded broiler marinated (83.65% meat) and nonmarinated (100% meat) breast and thigh and in a 50:50 blend of breast and thigh meat. The assay uses a self-indicating substrate that, when acted upon by ACP, loses a phosphate radical and becomes a highly fluorescent compound. Cooked meat is added to deionized distilled water in a 1:3 ratio, blended with a hand-held homogenizer, and then centrifuged at 2500 relative centrifugal force for 5 min. ACP activity in the filtrate is measured after shaking on a Vortex mixer 75 microL of the extract with a pH 5.00 acetate buffer containing a nonfluorescent aromatic monophosphoric ester substrate. The rate of fluorophore formation is monitored during a 3 min incubation period (38 degrees C) in a fluorometer, and ACP enzyme activity (mU/kg sample) is calculated. Three laboratories analyzed 6 cooked poultry products (marinated and nonmarinated breast, thigh, and 50:50 breast/thigh blend). Five cooking temperatures were used to generate different ACP activity levels, which were replicated twice with duplicate samples and duplicate sample tests representing 720 data points. Log10 ACP activity (mU/kg sample) performance repeatability and reproducibility standard deviations (sr and sR) and relative standard deviations (RSDr and RSDR) over 5 cooking treatments for 6 products were as follows: marinated breast: sr = 0.02, sR = 0.08, RSDr = 0.60%, RSDR = 2.12%; nonmarinated breast: sr = 0.02, sR = 0.04, RSDr = 0.66%, RSDR = 1.29%; marinated thigh: sr = 0.01, = 0.01, RSDr = 0.37%, RSDR = 0.37%; nonmarinated thigh: sr = 0.02, sR = 0.05, RSDr = 0.53%, RSDR = 1.43%; marinated 50:50 breast/thigh blend: sr = 0.01, sR = 0.05, RSDr = 0.36%, RSDR = 1.31%; nonmarinated 50:50 breast/thigh blend: sr = 0.01, sR = 0.04, RSDr = 0.32%, RSDR = 1.12%.

Isolation, cultivation and characterization of head kidney macrophages from Atlantic cod, Gadus morhua L.

Head kidney macrophages from Atlantic cod, Gadus morhua L., were isolated by density sedimentation and maintained under serum‐free conditions for up to one week. The cells adhered and spread well on glass and plastic, were highly phagocytic, and had typical macrophage morphology as shown by phase contrast and scanning and transmission electron microscopy. Histochemical studies with the light microscope showed that the macrophages were acid phosphatase and non‐specific esterase positive, and alkaline phosphatase and peroxidase negative. Compared with unstimulated control cells, LPS‐treated cells showed enhanced superoxide anion formation, as measured by the reduction of nitroblue tetrazolium, and increased levels of acid phosphatase activity.