Do broiler chicks have a cognitive representation of food quality?. Appetitive, behavioural and ingestive responses to a change in diet quality

It has been observed that when a new diet formulation, or a new batch of the same diet formulation, is presented to poultry, there is a transitory suppression of feeding. It appears that the birds do not recognise the food as being edible, or classify it as being 'unknown'. In order to understand more about food recognition and rejection, the aim of this experiment was to determine whether cognitive processes are involved. Sixteen groups of four broiler chicks were used, and were fed a low quality diet in their home pens. The groups of chicks were trained to run a winding maze to gain access to a high quality diet in a test trough for 15min per day. When training was completed, the feed in the test trough for eight of the groups was changed to that which they received in the home pen, while the other eight groups received no change as a control. Time to traverse the runway did not show an immediate decrease on the day after the change (P>0.05) as would be expected if the birds used a cognitive comparison to determine speed of approach to the test trough. However, the experimental groups were significantly slower compared to the control groups after 4 days (P<0.05). The behaviour observed on the day of the change was indicative of frustration with more scratching and hurried movements shown (P<0.05), and less pecking at feed (P<0.01). Food consumption was lower for experimental groups compared to control groups on all days from the day of change onward (P<0.001). It was concluded that although there was no definitive evidence for the presence of a cognitive representation of food, this may have been due in part to the testing of groups of birds rather than individuals, and the way in which food quality is perceived. The occurrence of behaviours indicative of frustration suggest that a cognitive expectation may have been present.     

Performance of established native seedlings in relation to invasive Lantana camara, rainfall and species’ habitat preferences in a seasonally dry tropical forest

Native species’ response to the presence of invasive species is context specific. This response cannot be studied in isolation from the prevailing environmental stresses in invaded habitats such as seasonal drought. We investigated the combined effects of an invasive shrub Lantana camara L. (lantana), seasonal rainfall and species’ microsite preferences on the growth and survival of 1,105 naturally established seedlings of native trees and shrubs in a seasonally dry tropical forest. Individuals were followed from April 2008 to February 2010, and growth and survival measured in relation to lantana density, seasonality of rainfall and species characteristics in a 50-ha permanent forest plot located in Mudumalai, southern India. We used a mixed effects modelling approach to examine seedling growth and generalized linear models to examine seedling survival. The overall relative height growth rate of established seedlings was found to be very low irrespective of the presence or absence of dense lantana. 22-month growth rate of dry forest species was lower under dense lantana while moist forest species were not affected by the presence of lantana thickets. 4-month growth rates of all species increased with increasing inter-census rainfall. Community results may be influenced by responses of the most abundant species, Catunaregam spinosa, whose growth rates were always lower under dense lantana. Overall seedling survival was high, increased with increasing rainfall and was higher for species with dry forest preference than for species with moist forest preference. The high survival rates of naturally established seedlings combined with their basal sprouting ability in this forest could enable the persistence of woody species in the face of invasive species.     

Infestation by a Nalepella species induces emissions of α- and β-farnesenes, (−)-linalool and aromatic compounds in Norway spruce clones of different susceptibility to the large pine weevil

The emissions of spruce grafts (Picea abies), caused by infestation of an acarid species of the genus Nalepella were investigated. Volatiles of three clones, both healthy and infested, with different susceptibility to the large pine weevil Hylobius abietis were collected by solid phase micro extraction (SPME) and analyzed by gas chromatograph coupled to mass-spectrometry (GC-MS). In addition, enantiomers of the main chiral compounds were separated by a two dimensional-gas chromatograph (2D-GC). In the characteristic flower-like fragrances emitted by the infested grafts large amounts of E-β-farnesene, E,E-α-farnesene, (−)-linalool, methyl salicylate and minute amounts of benzyl alcohol, E-anethole, methyl benzoate, neral and geranial were found. All together, these compounds could explain the characteristic scent emitted by the infested seedlings. Large differences in the emissions of E-β-farnesene, E,E-α-farnesene and methyl salicylate were found between but not within the clones. Handling editor: Heikki Hokkanen.     

Glycation <Emphasis Type="Italic">vs</Emphasis>. glycosylation: a tale of two different chemistries and biology in Alzheimer’s disease

In our previous studies, we reported that the activity of an anti-oxidant enzyme, Cu,Zn-superoxide dismutase (Cu,Zn-SOD) became decreased as the result of glycation in vitro and in vivo. Glycated Cu,Zn-SOD produces hydroxyl radicals in the presence of transition metals due to the formation of a Schiff base adduct and a subsequent Amadori product. This results in the site-specific cleavage of the molecule, followed by random fragmentation. The glycation of other anti-oxidant enzymes such as glutathione peroxidase and thioredoxin reductase results in a loss or decrease in enzyme activity under pathological conditions, resulting in oxidative stress. The inactivation of anti-oxidant enzymes induces oxidative stress in aging, diabetes and neurodegenerative disorders. It is well known that the levels of Amadori products and N^e-(carboxylmethyl)lysine (CML) and other carbonyl compounds are increased in diabetes, a situation that will be discussed by the other authors in this special issue. We and others, reported that the glycation products accumulate in the brains of patients with Alzheimer’s disease (AD) patients as well as in cerebrospinal fluid (CSF), suggesting that glycation plays a pivotal role in the development of AD. We also showed that enzymatic glycosylation is implicated in the pathogenesis of AD and that oxidative stress is also important in this process. Specific types of glycosylation reactions were found to be up- or downregulated in AD patients, and key AD-related molecules including the amyloid-precursor protein (APP), tau, and APP-cleaving enzymes were shown to be functionally modified as the result of glycosylation. These results suggest that glycation as well as glycosylation are involved in oxidative stress that is associated with aging, diabetes and neurodegenerative diseases such as AD.     

Defense response in non-genomic model species: methyl jasmonate exposure reveals the passion fruit leaves’ ability to assemble a cocktail of functionally diversified Kunitz-type trypsin inhibitors and recruit two of them against papain

Main conclusion

Multiplicity of protease inhibitors induced by predators may increase the understanding of a plant’s intelligent behavior toward environmental challenges. Information about defense mechanisms of non-genomic model plant passion fruit (Passiflora edulis Sims) in response to predator attack is still limited. Here, via biochemical approaches, we showed its flexibility to build-up a broad repertoire of potent Kunitz-type trypsin inhibitors (KTIs) in response to methyl jasmonate. Seven inhibitors (20–25 kDa) were purified from exposed leaves by chromatographic techniques. Interestingly, the KTIs possessed truncated Kunitz motif in their N-terminus and some of them also presented non-consensus residues. Gelatin-Native-PAGE established multiple isoforms for each inhibitor. Significant differences regarding inhibitors’ activity toward trypsin and chymotrypsin were observed, indicating functional polymorphism. Despite its rarity, two of them also inhibited papain, and such bifunctionality suggests a recruiting process onto another mechanistic class of target protease (cysteine-type). All inhibitors acted strongly on midgut proteases from sugarcane borer, Diatraea saccharalis (a lepidopteran insect) while in vivo assays supported their insecticide properties. Moreover, the bifunctional inhibitors displayed activity toward midgut proteases from cowpea weevil, Callosobruchus maculatus (a coleopteran insect). Unexpectedly, all inhibitors were highly effective against midgut proteases from Aedes aegypti a dipteran insect (vector of neglected tropical diseases) opening new avenues for plant-derived PIs for vector control-oriented research. Our results reflect the KTIs’ complexities in passion fruit which could be wisely exploited by influencing plant defense conditions. Therefore, the potential of passion fruit as source of bioactive compounds with diversified biotechnological application was strengthened.     

Leaf functional response to increasing atmospheric CO(2) concentrations over the last century in two northern Amazonian tree species: a historical δ(13) C and δ(18) O approach using herbarium samples

We assessed the extent of recent environmental changes on leaf morphological (stomatal density, stomatal surface, leaf mass per unit area) and physiological traits (carbon isotope composition, δ(13)C(leaf) , and discrimination, Δ(13)C(leaf) , oxygen isotope composition, δ(18)O(leaf) ) of two tropical rainforest species (Dicorynia guianensis; Humiria balsamifera) that are abundant in the Guiana shield (Northern Amazonia). Leaf samples were collected in different international herbariums to cover a 200 year time-period (1790-2004) and the whole Guiana shield. Using models describing carbon and oxygen isotope fractionations during photosynthesis, different scenarios of change in intercellular CO(2) concentrations inside the leaf (C(i)), stomatal conductance (g), and photosynthesis (A) were tested in order to understand leaf physiological response to increasing air CO(2) concentrations (C(a)). Our results confirmed that both species displayed physiological response to changing C(a) . For both species, we observed a decrease of about 1.7‰ in δ(13)C(leaf) since 1950, without significant change in Δ(13)C(leaf) and leaf morphological traits. Furthermore, there was no clear change in δ(18)O(leaf) for Humiria over this period. Our simulation approach revealed that an increase in A, rather than a decrease in g, explained the observed trends for these tropical rainforest species, allowing them to maintain a constant ratio of C(i)/C(a) .