Effects of mixed housing of birds from two genetic lines of laying hens on open field and manual restraint responses

Birds from Rhode Island Red (RIR) origin show a lower fear response and less feather pecking than birds from White Leghorn (WL) origin. This study investigated whether responses in fear eliciting tests were affected if RIR and WL birds were housed together. Experimental groups contained either birds from one line only ('pure' groups) or an equal number of RIR and WL birds ('mixed' groups). These arrangements were maintained from hatch onwards, throughout the rearing and laying period. Birds were subjected to open field tests at 5-6 weeks and 17-18 weeks of age and to manual restraint tests at 7-8 weeks and 24 weeks of age. RIR birds were more active in both open field tests and in the manual restraint test at 24 weeks of age as compared with WL birds. RIR birds from pure groups were more active in the open field test at 17-18 weeks and in the manual restraint test at 24 weeks of age than RIR birds from mixed groups. These results suggest that otherwise low fearful RIR birds may adopt a higher fear response if they are housed together with more fearful conspecifics. These effects do not emerge until after 8 weeks of age.     

Potential use of seaweeds in the laying hen ration to improve the quality of n-3 fatty acid enriched eggs

An association between dietary fish oil and decreased yolk weight and reduced sensory quality of eggs has been reported when eggs are enriched with n-3 FA from fish oil. Seaweeds are an important source of compounds that seem to increase egg weight when included in the laying hen diet. The objectives of this study were to determine the influence of the dietary seaweeds Macrocystis pyrifera, Sargassum sinicola and Enteromorpha sp. on the physical quality, lipid composition and consumer acceptability of n-3 FA enriched eggs. One-hundred and forty-four 35-week-old Leghorn hens were randomly distributed in four treatments that consisted of the inclusion of 2% of sardine oil (SO) and 10% of each marine alga (MA) in laying hens' diets; a control diet (C) was also prepared. The study lasted 8 weeks and egg physical quality, egg lipids and sensory attributes were evaluated. The results showed that incorporation of 10% M. pyrifera in the diets is an effective way of increasing the n-3 FA content, the albumen height and yolk color, but not the egg weight, when these are enriched with n-3 FA from fish oil. The egg flavor was also not affected.     

Effect of the combined supplementation of diets with increasing levels of fish and linseed oils on yolk fat composition and sensorial quality of eggs in laying hens

Yolk fatty acid (FA) concentrations and egg quality were evaluated with respect to the inclusion of different levels of marine fish oil (MFO) and linseed oil (LO) in a basal diet. Ten diets were arranged factorially with two levels of MFO addition (15 and 17 g/kg) and five levels of linseed oil (1, 2, 3, 4 and 5 g/kg). Two commercial feeds with no n-3 FA sources added, or containing 15 g MFO/kg served as controls for egg sensorial quality traits. Type of diet did not affect egg production traits, nor total fat content in yolk or saturated and monounsaturated FA concentration in yolk fat. An increase in the inclusion of MFO from 15 to 17 g/kg increased (P<0.05) egg yolk content of total n-3 FA, C_20:5 n-3 and C_22:6 n-3 by 3.3, 9.8 and 3.5%, respectively. Linseed oil addition increased linearly (P<0.001) the level of total n-3 FA and the proportion of C_18:3 n-3, C_20:5 n-3, C_22:5 n-3 and C_22:6 n-3 retained in yolk fat by respectively 131, 12.0, 6.9 and 20.7% between extreme diets. Efficiency of retention of n-3 FA decreased (P<0.001) with dietary level of n-3 FA, and with the dietary ratio of MFO to LO. Both MFO and LO addition decreased (P<0.001) C_20:4 n-6 to C_18:2 n-6 ratio in yolk. Sensorial quality of eggs was not affected by treatments and did not differ with respect of that obtained in commercial n-3 FA enriched eggs. No interaction was found between LO and MFO addition for any of the traits studied. Regression equations have been calculated in order to predict efficiency of retention and yolk fat content of LC n-3 and n-6 FA from dietary characteristics.     

A direct approach to the measurement of genetic variation in fish populations: applications of the polymerase chain reaction to studies of Atlantic cod, Gadus morhua L.

We used the polymerase chain reaction (PCR) and direct DNA sequencing to study genetic variation within and among populations of Atlantic cod, Gadus morhua , in the western North Atlantic. In a 307 bp region of the mitochondrial cytochrome b gene, 24 variable nucleotide positions define 24 genotypes, which differ by from one to six nucleotide substitutions. Greenland cod ( G. ogac ) differs from the most similar G. morhua genotype by an additional 12 nucleotide substitutions. Silent transitions dominate both intra- and interspecific comparisons, however four nucleotide substitutions within morhua result in amino acid replacements. Direct sequencing of DNA reveals substantially more of the genetic variation that exists within and between species than do previous indirect methods based on restriction fragment length polymorphisms, and thus has far greater potential to quantify such differences as may exist among fish stocks. Preliminary experiments also indicate that automation of DNA sequencing provides an efficient, rapid, and accurate means for detection of genetic variation in natural populations offish.     

Transgenic rice as a system to study the stability of transgene expression: multiple heterologous transgenes show similar behaviour in diverse genetic backgrounds

The success of contemporary breeding programmes involving genetic engineering depends on the stability of transgene expression over many generations. We studied the stability of transgene expression in 40 independent rice plant lines representing 11 diverse cultivated varieties. Each line contained three or four different transgenes delivered by particle bombardment, either by cotransformation or in the form of a cointegrate vector. Approximately 75% of the lines (29/40) demonstrated Mendelian inheritance of all transgenes, suggesting integration at a single locus. We found that levels of transgene expression varied among different lines, but primary transformants showing high-level expression of the gna, gusA, hpt and bar transgenes faithfully transmitted these traits to progeny. Furthermore, we found that cry1Ac and cry2A transgene expression was stably inherited when primary transformants showed moderate or low-level expression. Our results show that six transgenes (three markers and three insect-resistance genes) were stably expressed over four generations of transgenic rice plants. We showed that transgene expression was stable in lines of all the rice genotypes we analysed. Our data represent a step forward in the transfer of rice genetic engineering technology from model varieties to elite breeding lines grown in different parts of the world. Received: 22 March 1999 / Accepted: 6 December 1999     

Effect of pepstatin A on the virulence factors of Candida albicans strains isolated from vaginal environment of patients in three different clinical conditions

The aspartate proteinase inhibitor pepstatin A was used to study a possible correlation among proteinase activity and other virulence factors of Candida albicans strains isolated from the vaginal environment of patients in three different clinical conditions: asympthomatic, vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC). The addition of 1.0 μM pepstatin A did not have any significant effect on hyphae formation, biofilm production and in the cell surface hydrofobicity of isolates in the three different clinical conditions. However, pepstatin A reduced the adherence of C. albicans to vaginal mucosa epithelial cells (53.1, 48.7 and 59.9%, respectively to isolates from asymptomatic, VVC and RVVC patients). This result suggests that the secreted aspartate proteinases (Saps) of this fungal pathogen may have auxiliary roles in cellular adhesion.     

Influence of solubility-enhancing fusion proteins and organic solvents on the in vitro biocatalytic performance of the carotenoid cleavage dioxygenase AtCCD1 in a micellar reaction system

The influence of the solubility-enhancing fusion proteins glutathione-S-transferase (GST) and NusA on the heterologous expression and in vitro biocatalytic performance of the carotenoid cleavage dioxygenase AtCCD1 from Arabidopsis thaliana was investigated. A micellar dispersion of the water-insoluble model substrate β-apo-8′-carotenal in combination with Triton X-100 was used for the spectrophotometric in vitro assays. Specific activity in the cellular extract was twofold increased by the use of GST as a carrier protein, whereas it was decreased by 70% when fused with NusA. Reduced molar activity of the purified fusion proteins was observed, which could not be regained by proteolytic removal of the carrier protein. The addition of organic solvents in the form of short-chain aliphatic alcohols positively influenced the enzyme activity. Optimization of the reaction medium led to an 18-fold activation, and a clear correlation could be found between the organic solvent concentration required for maximum activation and the log P of the solvent. The results provide a foundation for the development towards the application of carotenoid cleavage dioxygenases as in vitro biocatalysts for the production of norisoprenoids and apocarotenals from carotenoids.     

A new species and three new combinations in Cyphellophora, with a note on the taxonomic affinities of the genus, and its relation to Kumbhamaya and Pseudomicrodochium.

Cyphellophora guyanensis sp. nov., isolated from leaf litter in French Guyana, is described and illustrated. This fungus is characterized by ampulliform to flask-shaped phialides, with a conspicuous, funnel-shaped collarette, and nearly straight to falcate or slightly sigmoid, (2−)3–6 septate conidia. Cyphellophora guyanensis is compared to the other Cyphellophora species, and the latter genus is compared to Kumbhamaya and Pseudomicrodochium. Kumbhamaya indica, P. fusarioides, and P. suttonii are transferred to Cyphellophora. The phylogenetic relationships of Cyphellophora with other genera of ascomycetes and related mitosporic fungi were inferred from the analysis of the partial nuclear ribosomal DNA SSU sequences data. The analysis supports a placement of Cyphellophora in Chaetothyriales, and probably in the Herpotrichiellaceae This revised version was published online in August 2006 with corrections to the Cover Date.     

Kinetic studies on the Rhizomucor miehei lipase catalyzed esterification reaction of oleic acid with 1-butanol in a biphasic system

The kinetics of the esterification of oleic acid with 1-butanol catalyzed by free Rhizomucor miehei lipase in a biphasic system was studied in a batch reactor. The reaction appeared to proceed via a Ping Pong bi–bi mechanism with 1-butanol inhibition. The kinetic constants of the model were determined from experiments at 30 °C with initial concentrations of oleic acid and 1-butanol in the organic phase and 0.05–0.2 g L⁻¹ enzyme in the aqueous phase. The model was used to simulate the batch concentration profiles of the product as well as the initial reaction rates. Agreement of the model with both the batch concentration profiles (average error of 7.2%) and the initial reaction rate per experiment (average error of 16.0%) was good.     

Interspecific interactions in a tri-trophic arthropod system: effects of a spider on the survival of larvae of three predatory ladybirds in relation to aphids

The effects of the crab spider, Misumenops tricuspidatus (Fabricius), on the larval survival of three ladybird species, Harmonia axyridis Pallas, Coccinella septempunctata L., and Propylea japonica L., in relation to aphids were investigated in the laboratory. Predation by the spider on the three ladybird species differed. All the larvae of C. septempunctata, none of H. axyridis, and an intermediate number of P. japonica were attacked and eaten by the spider. All the larvae of H. axyridis suffered mortality due to cannibalism or starvation in the treatments with and without a spider. In case of C. septempunctata, however, mortality in the early instars was significantly greater in the treatment with a spider than without a spider and no larvae developed into pupae due to predation. In the treatment without a spider, the majority of the larvae in the former treatment suffered mortality due to cannibalism or starvation, and only 13.3% of larvae developed into the adult stage. In the case of P. japonica, mortality was mainly attributed to predation in the treatment with a spider and only 26.7% became adult. In comparison, 86.7% of larvae survived to the adult stage in the treatment without a spider. In addition, in both H. axyridis and C. septempunctata, the development of young larvae was significantly slower in the presence of a spider, but this was not the case with the older larvae of H. axyridis, which indicates that the effect of the spider on larval development changed with the developmental stage of the larvae in this species. However, the spider had no significant effect on the developmental time of P. japonica larvae. Although both the spider and the ladybirds significantly affected the number of aphids, they did not have an additive effect on aphid abundance. The interactions between the spider and the ladybirds, such as intraguild predation or competition, caused them to reduce aphid population density less than the ladybirds did on their own. The effect of the spider on the larval performance of three predatory ladybirds was found to be unequal in terms of their vulnerability to predation and rate of larval development and it depended on the species and developmental stage of the ladybird.     

A comparative immunohistochemical study on a galanin‐like peptide in the neuroendocrine system of the alimentary canal of three species of siluriform catfishes

Immunohistochemical examination of the galaninergic and the diffuse endocrine systems of the alimentary canal of three catfish species, Ameiurus melas, Silurus glanis and Clarias gariepinus showed the presence of galanin‐like immunoreactive endocrine cells in the stomachs and the proximal intestines and a galanin‐like immunoreactivity within the enteric intramural neurons. The three species differed notably in the relative abundance of galaninergic neurons of the digestive system. A galanin‐like peptide was detected in a high number of nerve bundles and nerve fibres running through the exocrine parenchyma and the endocrine islets of the pancreas of all three species. It is conceivable that the galaninergic system in these species plays a role in regulating gut muscle activity, in modulating mucosal secretive and absorptive processes, and in controlling pancreatic hormone secretion.