Effect of the 1990 die-off in the northern Italian seas on the developmental stability of the striped dolphin Stenella coeruleoalba (Meyen, 1833)

Developmental stability of the community of striped dolphins, Stenella coeruleoalba (Meyen, 1833), that died during the Mediterranean epizootic of 1990 was compared with that of the population prior to and after the epizootic, to assess whether animals that died were the developmentally less stable individuals in the population. Significantly higher levels of fluctuating asymmetry (FA) were found in those individuals that died. Tissue levels of organochlorine pesticide residues and PCBs were determined and the correlation between contaminant concentration and FA was tested. No correlations were found between the contaminant level and FA.     

Cytogenetic Follow-Up in a Case With a Primary Cutaneous Melanoma and Five Metastatic Lesions

Cytogenetic analyses conducted on several cases of melanoma have contributed to the identification of the chromosomal regions where the sequences responsible for malignant transformation and the evolution of this tumor are probably located. With regard to these problems, it is very important to have the possibility to analyze, through the use of cytogenetics, both the primary melanoma and the metastatic lesions from the same patient. We present a case in which the primary melanoma and five different metastases were studied by using cytogenetics. The primary tumor showed an inversion of chromosome 1 where the p36 region, often proposed in literature as the location of a melanoma susceptibility gene, was involved. Three cutaneous and one lymphonodal metastases presented the same nine clonal chromosomal aberrations. In particular, one is a further rearrangement of the marker present in the primary tumor; another is a deletion of the 9p21pter region in which the p16 gene is located. Our results can provide a contribution to the hypothesis of the location of a candidate gene for melanoma in the 1p36 region and can also underscore the role of the 9p21 region in the progression of melanoma.     

Vimentin in the Central Nervous System

Intermediate filament proteins were identified by two-dimensional gel electrophoresis in urea extracts of rat optic nerves undergoing Wallerian degeneration and in cytoskeletal preparations of rat brain and spinal cord during postnatal development. The glial fibrillary acidic (GFA) protein and vimentin were the major optic nerve proteins following Wallerian degeneration. Vimentin was a major cytoskeletal component of newborn central nervous system (CNS) and then progressively decreased until it became barely identifiable in mature brain and spinal cord. The decrease of vimentin occurred concomitantly with an increase in GFA protein. A protein with the apparent molecular weight of 61,000 and isoelectric point of 5.6 was identified in both cytoskeletal preparations of brain and spinal cord, and in urea extracts of normal optic nerves. The protein disappeared together with the polypeptides forming the neurofilament triplet in degenerated optic nerves.     

Increase of Brain Tryptophan caused by Drugs which stimulate Serotonin Synthesis

THE concentrations of tryptophan normally present in the mammalian brain are below the Michaelis constant (K_m) of tryptophan hydroxylase^1,2, suggesting that the rate of serotonin synthesis depends more on the concentration of brain tryptophan than on the amount of enzyme. We wish to report that various treatments which have been shown to increase brain serotonin synthesis also increase the concentration of tryptophan in brain. Conversely, p-chlorophenylalanine (PCPA), which inhibits serotonin synthesis³, decreases tryptophan in brain.     

The ‘truck‐driver’ effect in leaf‐cutting ants: how individual load influences the walking speed of nest‐mates

The foraging behaviour of social insects is highly flexible because it depends on the interplay between individual and collective decisions. In ants that use foraging trails, high ant flow may entail traffic problems if different workers vary widely in their walking speed. Slow ants carrying extra‐large loads in the leaf‐cutting ant Atta cephalotes L. (Hymenoptera: Formicidae) are characterized as ‘highly‐laden’ ants, and their effect on delaying other laden ants is analyzed. Highly‐laden ants carry loads that are 100% larger and show a 50% greater load‐carrying capacity (i.e. load size/body size) than ‘ordinary‐laden’ ants. Field manipulations reveal that these slow ants carrying extra‐large loads can reduce the walking speed of the laden ants behind them by up to 50%. Moreover, the percentage of highly‐laden ants decreases at high ant flow. Because the delaying effect of highly‐laden ants on nest‐mates is enhanced at high traffic levels, these results suggest that load size might be adjusted to reduce the negative effect on the rate of foraging input to the colony. Several causes have been proposed to explain why leaf‐cutting ants cut and carry leaf fragments of sizes below their individual capacities. The avoidance of delay in laden nest‐mates is suggested as another novel factor related to traffic flow that also might affect load size selection The results of the presennt study illustrate how leaf‐cutting ants are able to reduce their individual carrying performance to maximize the overall colony performance.     

Effects of the maternal and pre‐adult host plant on adult performance and preference in the pea aphid,Acyrthosiphon pisum

Abstract 1. The taxon known as the pea aphid, Acyrthosiphon pisum, is composed of a series of host plant associated populations and is widely used as a model system to explore ecological speciation and the evolution of specialisation. It is thus important to know how maternal and pre‐adult experience influences host plant utilisation in this species. 2. The relative importance of the maternal and pre‐adult host plant for adult fecundity and host preference was investigated using three aphid clones collected from Lathyrus pratensis and maintained on Lathyrus or Vicia faba. 3. No significant effects of the maternal host plant on offspring fecundity were detected. 4. The host plant on which the aphid grew up influenced adult fecundity, although in a complex way that depended on both the adult host plant species and when after transfer to the test plant fecundity was assessed. 5. All three clones preferred to colonise Lathyrus over Vicia, and this preference was stronger for aphids raised on Lathyrus. 6. The significance of the results for studies of the evolution of specialisation and speciation that employ A. pisum is discussed.     

Total evidence phylogenetic analysis and reclassification of Euschistus Dallas within Carpocorini (Hemiptera: Pentatomidae: Pentatominae)

Robust phylogenetic hypotheses have become key for studies addressing the evolutionary biology and ecology of various groups of organisms. In the species‐rich heteropteran superfamily Pentatomoidea, phylogenies at lower taxonomic levels are still scarce and mostly employ exclusively morphological data. In this study, we conducted a total evidence phylogeny focusing on the tribe Carpocorini (Pentatomidae), using morphological data and four DNA markers (COI, Cytb, 16S and 28S rDNA; ～2330 bp; 32 taxa) in order to investigate the relationships within Euschistus Dallas, one of the most speciose pentatomid genera, and between Euschistus and related genera. Our hypotheses generated by maximum likelihood and Bayesian inference show that the current taxonomic composition and classification of Euschistus and allied genera are in need of revision. Euschistus was recovered as nonmonophyletic, with the subgenera forming four independent lineages: Euschistus (Euschistus) and Euschistus (Lycipta) Stål are sister groups; Euschistus (Euschistomorphus) Jensen‐Haarup is more closely related to Dichelops Spinola and Agroecus Dallas; and Mitripus Rolston is divided into two clades closely related to Sibaria Stål and Ladeaschistus Rolston. We chose not to change the classification of E. (Euschistomorphus) until further data become available, and propose to split Euschistus into three genera with the exclusion of Euschistus (Mitripus) and all of its species. Here we elevate Mitripus to genus rank to include M. acutus comb.n. , M. convergens comb.n. and M. legionarius comb.n. , and propose Adustonotus Bianchi gen.n. to include A. anticus comb.n. , A. latus comb.n. , A. tauricornis comb.n. , A. grandis comb.n. , A. hansi comb.n. , A. paranticus comb.n. , A. irroratus comb.n. and A. saramagoi comb.n. We also provide identification keys to the genera Adustonotus gen.n. , Ladeaschistus, Mitripus n. rank and Sibaria, here defined as the Mitripus genus group, and to the species of Mitripus and Adustonotus gen.n. Our results provide insights into the current status of the classification of the Pentatomidae, suggesting the need for phylogenetic analyses at different taxonomic levels within stink bugs. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:E09D2675‐0F2B‐4AAE‐9837‐257E0B18BC52 .     

Water economy and photosynthesis of the CAM plant Senecio medley-woodii during increasing drought

Abstract CO₂ gas exchange, transpiration and water uptake of the succulent Senecio medley-woodii were monitored simultaneously during a 10 day period of increasing drought. The measurements were performed with a combination of a CO₂ gas exchange chamber and a potometer system. Further, leaf water relations and CO₂ gas exchange of a branched potted plant were measured during 15 days of water shortage. The enhancement of CO₂ dark fixation at the beginning of drought modifies the leaf water relations according to the increased malate accumulation during the dark period. The enhancement of water uptake from dusk to dawn corresponds to the increase of Ψ_leaf during the same period. Therefore at the beginning of drought a short time improvement of plant water status through the increased CO₂ dark fixation and malate accumulation can be maintained.