Fertility life table of Trichogramma pretiosum and Trichogramma acacioi on eggs of Anagasta kuehniella at different temperatures

Species of the Trichogramma genus are among the most important ones for biological control. The objective of this research was to evaluate parasitism potential of two species of Trichogramma on eggs of Anagasta kuheniella through life fertility table, at temperatures between 15ºC and 35ºC. These species were collected in the State of Espírito Santo parasitising eggs of the avocado defoliator Nipteria panacea. Trichogramma pretiosum and T. acacioi showed adequate reproductive potential between 15ºC and 35ºC which indicates possibilities of using them in biological control programs in avocado plantations.

Eumelanin- and pheomelanin-based colour advertise resistance to oxidative stress in opposite ways.

The control mechanisms and information content of melanin-based colourations are still debated among evolutionary biologists. Recent hypotheses contend that molecules involved in melanogenesis alter other physiological processes, thereby generating covariation between melanin-based colouration and other phenotypic attributes. Interestingly, several molecules such as agouti and glutathione that trigger the production of reddish-brown pheomelanin have an inhibitory effect on the production of black/grey eumelanin, whereas other hormones, such as melanocortins, have the opposite effect. We therefore propose the hypothesis that phenotypic traits positively correlated with the degree of eumelanin-based colouration may be negatively correlated with the degree of pheomelanin-based colouration, or vice versa. Given the role played by the melanocortin system and glutathione on melanogenesis and resistance to oxidative stress, we examined the prediction that resistance to oxidative stress is positively correlated with the degree of black colouration but negatively with the degree of reddish colouration. Using the barn owl (Tyto alba) as a model organism, we swapped eggs between randomly chosen nests to allocate genotypes randomly among environments and then we measured resistance to oxidative stress using the KRL assay in nestlings raised by foster parents. As predicted, the degree of black and reddish pigmentations was positively and negatively correlated, respectively, with resistance to oxidative stress. Our results reveal that eumelanin- and pheomelanin-based colourations can be redundant signals of resistance to oxidative stress.

Predation on common tern eggs by the yellow-legged gull at the Ebro Delta

The Ebro Delta holds a large seabird community, including a common tern (Sterna hirundo) local population of 3,085 pairs in 2000 which breeds scattered in several colonies. At El Canalot colony, 1,178 (1999) and 1,156 pairs (2000) of this species bred distributed in 32 and 38 sub-colonies respectively. These sub-colonies varied in size from 1 to 223 pairs and were placed near the main breeding colonies of yellow-legged gulls (Larus cachinnans) and Audouin´s gulls (L. audouinii), which are potential egg-predators of terns. We studied egg predation during 1999 (6 sub-colonies) and 2000 (27 sub-colonies). Overall, we found that 10.6% of the nests in 1999 and 16.7% in 2000 suffered partial or total egg predation, being total in 81.1% of the predatory events. Predation was significantly higher in small sub-colonies (< 11 pairs): 49.4% in 1999 and 75.5% in 2000. Only attacks from yellow-legged gulls were observed, and defence behaviour of terns was significantly more frequent against this gull species (40.5 hours of observation), suggesting that in most cases the egg predation recorded was due to this species. Probability of egg predation was significantly and negatively correlated with distance to the nearest yellow-legged gull sub-colony, although this relationship was no more significant after adjustment for sub-colony size. On the other hand, distance to the nearest Audouin´s gull sub-colony did not show any effect. Our results suggest that the impact of large gulls (at least yellow-legged gulls) upon smaller seabirds breeding in the area might be important, especially when they are breeding in small sub-colonies. Further studies are needed to analyse the general impact of large gulls upon the breeding populations of other colonial bird species in the area.

Comparison of methods by TLC and HPTLC for determination of aflatoxin M1 in milk and B1 in eggs

Milk and egg matrixes were assayed for aflatoxin M1 (AFM1) and B1 (AFB1) respectively, by AOAC official and modified methods with detection and quantification by thin layer chromatography (TLC) and high performance thin layer chromatography (HPTLC). The modified methods: Blanc followed by Romer, showed to be most appropriate for AFM1 analysis in milk. Both methods reduced emulsion formation, produced cleaner extracts, no streaking spots, precision and accuracy improved, especially when quantification was performed by HPTLC. The use of ternary mixture in the Blanc Method was advantageous as the solvent could extract AFM1 directly from the first stage (extraction), leaving other compounds in the binary mixture layer, avoiding emulsion formation, thus reducing toxin loss. The relative standard deviation (RSD%) values were low, 16 and 7% when TLC and HPTLC were used, with a mean recovery of 94 and 97%, respectively. As far as egg matrix and final extract are concerned, both methods evaluated for AFB1 need further studies. Although that matrix leads to emulsion with consequent loss of toxin, the Romer modified presented a reasonable clean extract (mean recovery of 92 and 96% for TLC and HPTLC, respectively). Most of the methods studied did not performed as expected mainly due to the matrixes high content of triglicerides (rich on saturated fatty acids), cholesterol, carotene and proteins. Although nowadays most methodology for AFM1 is based on HPLC, TLC determination (Blanc and Romer modified) for AFM1 and AFB1 is particularly recommended to those, inexperienced in food and feed mycotoxins analysis and especially who cannot afford to purchase sophisticated (HPLC,HPTLC) instrumentation.

Elimination of Salmonella enterica serovar Typhimurium in artificially contaminated eggs through correct cooking and frying procedures

Salmonellosis is a serious foodborne disease associated with the presence of bacteria in eggs or foods containing raw eggs. However, the use of appropriate procedures of cooking and frying can eliminate this contamination. There are few studies on the elimination of contamination of Salmonella in hens' eggs through typical frying procedures, especially for Salmonella enterica serovar Typhimurium (or S. typhimurium). The aim of this study was to determine the appropriate conditions for cooking and frying hens' eggs artificially contaminated with S. typhimurium, making them free of bacterial contamination. Hens' eggs were artificially contaminated with S. typhimurium and subjected to various processes of cooking, frying and food preparation. It was observed that the minimum time necessary to eliminate contamination through cooking procedures is 5 minutes after the water starts boiling, and also that, cooking in the microwave oven complete eliminates the bacterial contamination. When the eggs were fried on both sides, keeping the yolk hard, a complete bacterial elimination was observed. Mayonnaise prepared with vinegar presented a decrease in bacterial colonies when compared mayonese prepared with lemon.

Quality of eggs sold in different commercial establishments and the study of the conditions of storage

The objective of this study was to investigate the influence of storage conditions on the physicochemical (mass, albumen height, pH, and Haugh unit) and microbiological (Salmonella spp., determination of the Total and Thermotolerant Coliforms, and Counting of the Mesophilic Aerobic Bacteria) quality of eggs. In the first experiment, a questionnaire was applied, and 33 samples of eggs were collected for the Salmonella spp analysis. In the second experiment, the eggs were collected from supermarkets, open markets, and distributors for physicochemical analysis. In the third experiment, 175 eggs were collected from the distributor, packaged in cardboard boxes lined with plastic wrapping, stored at 5 °C and 28 °C, and the physicochemical and microbiological analyses were performed at 7, 14, and 21 days of storage. In the first experiment, 100% of the samples analyzed showed no Salmonella spp. In the second experiment, it was found that the values of physicochemical parameters were in agreement with those in the literature. However, in the third experiment, the physicochemical parameter results showed statistical difference during storage and temperatures studied. Salmonella spp. were found in the samples stored at room temperature and in the refrigerated samples. Mesophilic microorganisms with values ranging from <10 CFU g- 1 (estimated) to 8.0 × 10³ CFU g- 1 and coliforms to 4 NMP.g- 1 were also found, but the presence of E. coli was not confirmed.

Midge and the eggs.

Pertenece a un amplio programa infantil de lectura que abarca distintos niveles de edad y, por tanto, de conocimientos. Se abordan las necesidades de lectura en los niños y la amplia variedad de habilidades que necesitan adquirir para su aprendizaje y, se destaca, también, la importancia de la narración en las historias y el orden recomendado para su lectura. Trata la cómica historia de la compra de unos huevos para llevarlos a casa.

Effects of schistosoma mansoni worms and eggs on circulating cholesterol and liver lipids in mice

It has previously been shown that experimental infections of the parasitic trematode Schistosoma mansoni, the adult worms of which reside in the blood stream of the mammalian host, significantly reduced atherogenesis in apolipoprotein E gene knockout (apoE(-/-)) mice. These effects occurred in tandem with a lowering of serum total cholesterol levels in both apoE(-/-) and random-bred laboratory mice and a beneficial increase in the proportion of HDL to LDL cholesterol. To better understand how the parasitic infections induce these effects we have here investigated the involvement of adult worms and their eggs on lipids in the host. Our results indicate that the serum cholesterol-lowering effect is mediated by factors released from S. mansoni eggs, while the presence of adult worms seemed to have had little or no effect. It was also observed that high levels of lipids, particularly triacylglycerols and cholesteryl esters, present in the uninfected livers of both random-bred and apoE(-/-) mice fed a high-fat diet were not present in livers of the schistosome-infected mice. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Lethality of essential oil constituents towards the human louse, Pediculus humanus, and its eggs

Essential oils have been widely used in traditional medicine for the eradication of lice, including head lice, but due to the variability of their constitution the effects may not be reproducible. In an attempt to assess the contribution of their component monoterpenoids, a range of common individual compounds were tested in in vitro toxicity model against both human lice (Pediculus humanus, an accepted model of head lice lethality) and their eggs, at different concentrations. No detailed study into the relative potencies of their constituent terpenoids has so far been published. Adult lice were observed for lack of response to stimuli over 3 h and the LT50 calculated, and the percentage of eggs failing to hatch was used to generate ovicidal activity data. A ranking was compiled for adult lice and partially for eggs, enabling structure-activity relationships to be assessed for lethality to both, and showed that, for activity in both life-cycle stages, different structural criteria were required. (+)-Terpinen-4-ol was the most effective compound against adult lice, followed by other mono-oxygenated monocyclic compounds, whereas nerolidol was particularly lethal to eggs, but ineffective against adult lice. (c) 2006 Elsevier B.V. All rights reserved.

Growth of Salmonella enteritidis in artificially contaminated eggs: the effects of inoculum size and suspending media

Growth profiles of two isolates of Salmonella enteritidis phage type (PT) 4 inoculated into either the albumen of whole shell eggs or into separated albumen were found to be markedly affected by the size of the inoculum and the composition of the medium used to suspend the cells prior to inoculation. Using our model with an inoculum of two cells, multiplication of the Salmonella was not seen in 93% of eggs held at 20 degreesC for 8 days. In approximately 7% of eggs, however, growth occurred during the 8 days of storage. If the inoculum equaled or exceeded 25 cells per egg when eggs were subsequently stored at 20 degreesC, or 250 cells per egg when eggs were stored at 30 degreesC, high levels of growth of Salmonella in the egg occurred significantly more frequently than when the inoculum was two cells. High levels of growth were also seen more frequently if the inoculum was suspended in buffered peptone water or maximal recovery diluent rather than in phosphate buffered saline. Growth of Salmonella in separated albumen occurred very infrequently (1.1% of samples) at low inoculum levels and did not become significant until the inoculum was 250 cells or greater. Growth in the albumen was unaffected by the composition of the suspending medium. Provided that the inoculum was approximately 2 cells per egg and the bacteria were suspended in PBS, observed growth profiles of S. enteritidis inoculated into the albumen of whole eggs resembled those in naturally contaminated eggs. (C) 2001 Elsevier Science B.V. All rights reserved.

Analysis of wave phenomena in a morphogenetic mechanochemical model and an application to post-fertilization waves on eggs

Wave solutions to a mechanochemical model for cytoskeletal activity are studied and the results applied to the waves of chemical and mechanical activity that sweep over an egg shortly after fertilization. The model takes into account the calcium-controlled presence of actively contractile units in the cytoplasm, and consists of a viscoelastic force equilibrium equation and a conservation equation for calcium. Using piecewise linear caricatures, we obtain analytic solutions for travelling waves on a strip and demonstrate uiat the full nonlinear system behaves as predicted by the analytic solutions. The equations are solved on a sphere and the numerical results are similar to the analytic solutions. We indicate how the speed of the waves can be used as a diagnostic tool with which the chemical reactivity of the egg surface can be measured.

Increase of Cholesterol Oxidation and Decrease of PUFA as a Result of Thermal Processing and Storage in Eggs Enriched with n-3 Fatty Acids

In this work, cholesterol oxide formation and alteration of fatty acid composition were analyzed in n-3 enriched eggs under different storage periods and two temperatures. The eggs enriched with n-3 fatty acids were stored at 5 or 25 degrees C for 45 days and subsequently boiled or fried. For each treatment, 12 yolks were analyzed every 15 days including time zero. The concentrations of the cholesterol oxides 7-ketocholesterol, 7 beta-hydroxycholesterol, and 7 alpha-hydroxycholesterol increased during the storage period and were higher in fried eggs. Only the 7-ketocholesterol was affected by the storage temperature, and its concentration was highest in eggs stored at 25 degrees C. There was no significant difference in the contents of cholesterol and vitamin E at the different storage periods; however, the concentration of vitamin E decreased with thermal treatment. In addition, the n-3 polyunsaturated fatty acids, especially 18:3, 20:5, and 22:6, were reduced throughout the storage at 5 and 25 degrees C.

Colony dehydration and water collection by specialized caste in the leaf-cutting ant Atta sexdens rubropilosa

Social organization enables leaf-cutting ants to keep appropriate micro-ecological nest conditions for the fungus garden (their main food), eggs, larvae and adults. To maintain stability while facing changing conditions, individual ants must perceive destabilising factors and produce a proper behavioral response. We investigated behavioral responses to experimental dehydration in leaf-cutting ants to verify if task specialization exists, and to quantify the ability of ant sub-colonies for water management. Our setup consisted of fourteen sub-colonies, ten of which were randomly assigned to different levels of experimental dehydration with silica gel, whereas the remaining four were controls. The ten experimental sub-colonies were split into two groups, so that five of them had access to water. Diverse ant morphs searched for water in dehydrated colonies, but mainly a caste of small ants collected water after sources had been discovered. Size specialization for water collection was replicable in shorter experiments with three additional colonies. Ants of dehydrated colonies accumulated leaf-fragments on the nest entrance, and covering the fungus garden. Behaviors that may enhance humidity within the nests were common to all dehydration treatments. Water availability increased the life span of dehydrated colonies.