Modifications in DARPP‐32 phosphorylation pattern after repeated palatable food consumption undergo rapid habituation in the nucleus accumbens shell of non‐food‐deprived rats

In non‐food‐deprived rats a palatable meal induces a transient increase in dopamine output in the prefrontal cortex and nucleus accumbens shell and core; habituation to this response develops with a second palatable meal, selectively in the shell, unless animals are food‐deprived. A palatable meal also induces time‐dependent modifications in the dopamine and cAMP‐regulated phosphoprotein of Mr 32 000 (DARPP‐32) phosphorylation pattern that are prevented when SCH 23390, a selective dopamine D₁ receptor antagonist, is administered shortly after the meal. This study investigated whether dopaminergic habituation in the shell had a counterpart in DARPP‐32 phosphorylation changes. In non‐food‐deprived rats, two consecutive palatable meals were followed by similar sequences of modifications in DARPP‐32 phosphorylation levels in the prefrontal cortex and nucleus accumbens core, while changes after the second meal were blunted in the shell. In food‐deprived rats two consecutive meals also induced similar phosphorylation changes in the shell. Finally, SCH 23390 administered shortly after the first palatable meal in non‐food‐deprived rats inhibited DARPP‐32 phosphorylation changes in response to the first meal, and prevented the habituation to a second meal in terms of dopaminergic response and DARPP‐32 phosphorylation changes. Thus, dopamine D₁ receptor stimulation plays a role in the development of habituation.     

New Elements To Consider When Modeling the Hazards Associated with Botulinum Neurotoxin in Food

Botulinum neurotoxins (BoNTs) produced by the anaerobic bacterium Clostridium botulinum are the most potent biological substances known to mankind. BoNTs are the agents responsible for botulism, a rare condition affecting the neuromuscular junction and causing a spectrum of diseases ranging from mild cranial nerve palsies to acute respiratory failure and death. BoNTs are a potential biowarfare threat and a public health hazard, since outbreaks of foodborne botulism are caused by the ingestion of preformed BoNTs in food. Currently, mathematical models relating to the hazards associated with C. botulinum, which are largely empirical, make major contributions to botulinum risk assessment. Evaluated using statistical techniques, these models simulate the response of the bacterium to environmental conditions. Though empirical models have been successfully incorporated into risk assessments to support food safety decision making, this process includes significant uncertainties so that relevant decision making is frequently conservative and inflexible. Progression involves encoding into the models cellular processes at a molecular level, especially the details of the genetic and molecular machinery. This addition drives the connection between biological mechanisms and botulism risk assessment and hazard management strategies. This review brings together elements currently described in the literature that will be useful in building quantitative models of C. botulinum neurotoxin production. Subsequently, it outlines how the established form of modeling could be extended to include these new elements. Ultimately, this can offer further contributions to risk assessments to support food safety decision making.     

Biochemical (fatty acid profile) diversity in anostracan species of the genus Chirocephalus Prévost

Wild populations of five Chirocephalus species from Italy were tested for their fatty acid profiles, particularly essential fatty acids (EFA) in order to obtain information on species differences. Chirocephalus diaphanus, C. kerkyrensis and C. salinus were from temporary plain pools, whereas C. ruffoi and C. marchesonii came from a mountain pool and an astatic high altitude lake. Statistical comparisons of the results obtained revealed significant (P < 0.05) qualitative and quantitative differences among the species studied. Besides genetic make-up, other factors are presumably involved in these differences. Among these, environmental stability, and hence food quality and quantity, may play a major role, an hypothesis supported by previous findings regarding the possibility of manipulating fairy shrimp fatty acid patterns by using different diets. Further investigation is needed, however, on the fatty acid composition of the food resources from different habitats in relation to the fairy shrimp inhabitants. This revised version was published online in August 2006 with corrections to the Cover Date.     

On the occurrence of Streptocephalus torvicornis Waga 1842 (Crustacea,Anostraca) on a coastal island off Italy

The presence of Streptocephalus torvicornis on one coastal island off Italy (Cottarelli & Mura, 1995) is confirmed. Two years of sampling revealed an erratic pattern of occurrence, however, likely related to the unstable nature of the environmental characteristics. Such an unpredictability might be alternatively explained by a colonization-extinction process, or by adaptation to variations in annual weather (Donald, 1983). This revised version was published online in July 2006 with corrections to the Cover Date.