Neurophysiological and Behavioral Changes in Non-Target Wildlife Exposed to Organophosphate and Carbamate Pesticides: Thermoregulation, Food Consumption, and Reproduction

Originally utilized or developed as human poisons, anticholinesterasecompounds are among the most widely used pesticides in the worldand non-target wildlife are frequently exposed. Because thesecompounds primarily act by inhibiting acetylcholinesterase atsynapses within the central and peripheral nervous systems,the potential for altering physiological and behavioral responsesessential for survival and reproduction in exposed animals isgreat. We review the effects of acute but sublethal exposureto organophosphates and carbamates on thermoregulation (hypothermia),food consumption (anorexia and altered foraging behavior), andreproduction (altered hormone levels, reductions in clutch andlitter size, and alterations in reproductive behavior), andthe mechanisms believed to cause them. We believe these arethe direct toxic effects most likely to reduce populations offree-living birds and mammals within treated areas. Data fromstudies of captive birds and laboratory mammals and free-livingindividuals given controlled dosages are included with an emphasison information published within the last 5 years. The limitationsof existing data for determining the biological and regulatorysignificance of these effects are discussed.     

Pigmented Human Skin Equivalent: New Method of Reconstitution by Grafting an Epithelial Sheet Onto a Non-Contractile Dermal Equivalent

We have established a new protocol for reconstituting a pigmented human skin equivalent (PSE) and have evaluated its functional responses to environmental stimulus, UVB. The PSE is reconstituted by grafting an epithelial sheet consisting of keratinocytes and melanocytes onto a porous non-contractile dermal equivalent populated with mitotically and metabolically active fibroblasts. i) The PSE has a multilayered, well-differentiated epidermis with cuboidal basal cells and highly organised dermis with newly synthesised extracellular matrix components. ii) Ki67-positive proliferating keratinocytes (18.1 ± 7.4%) were detected on the basal layer of the epidermis. iii) Melanocytes located exclusively within the basal layer were detected by monoclonal antibody against tyrosinase-related protein (TRP-1). iv) After exposure to UVB (100 mJ/cm² per day) for 7 consecutive days, the intensity of TRP-1 staining was increased in the PSE, showing their functional state, whereas the number of melanocytes was not changed. This non-contractile and functioning new PSE is potentially useful as a model for studying the role of melanocyte-keratinocyte-fibroblast interactions in photoprotection of the skin in more complex cutaneous microenvironment than monolayer culture, and for developing in vitro disease models and therapeutic protocols with genetically altered cells both in epidermis and dermis.     

Monoterpenes emitted by the large pine weevil, Hylobius abietis (L.) feeding on Scots pine, Pinus sylvestris L.

Abstract. Attraction of the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae) to pine logs was enhanced by the presence of weevils already on the logs. We investigated the volatiles emitted by insects feeding on host trees to determine the mechanism of the attraction. Chemical analyses of the collected volatiles showed large amounts of monoterpenes. There were no qualitative differences in the collections, between Scots pine alone and pine plus feeding weevils, nor between males and females, mated or virgin. Strong quantitative differences in monoterpenes existed that were correlated to the surface of cut bark. Electroantennograms (EAGs) were recorded on male and female antennae stimulated by increasing doses of collected volatiles. EAGs for pine alone and pine plus weevils at the same stimulus loading in (a + P)-pinene gave superimposable curves. EAGs of male and female volatiles were also identical. These results suggest an attraction mediated by host plant allelochemicals rather than by an aggregation pheromone.     

Garden Warbler Sylvia borin migration in sub-Saharan West Africa: phenology and body mass changes

The Garden Warbler is a classic subject for the study of Palaearctic–African bird migration strategies. Most studies have considered the situation close to the breeding areas, while the African and especially the sub‐Saharan part of the species’ migration have received comparatively little attention. Here we use autumn and spring ringing data from Nigeria and The Gambia to study the movements and energetics of the species in West Africa during the non‐breeding season. The first Garden Warblers arrive south of the desert around the beginning of September, roughly at the same time as the median date for their passage through the Baltic Sea region and c. 3 weeks before their median passage date through southern Italy. In the Nigerian Sahel savannahs, where, owing to the rainy season and its associated increase in food availability, many more Garden Warblers stop over in autumn than in the dry spring, the median date of passage is 1 October. The body mass on arrival south of the desert is normally only a few grams more than the lean body mass (LBM; 15 g) – with a mean of 16.6 g (sd = ±1.8 g) in The Gambia and 17.4 g (sd = ±1.8 g) in the Nigerian Sahel. After resting and refuelling in the Sahel, Sudan and Guinea‐type savannahs the Garden Warblers depart during November–December for wintering areas further south. Before leaving, they again increase their body mass, with an average fuel load of c. 20%, and often more than 50% relative to LBM. Some of the birds passing through Nigeria probably spend midwinter around the Congo Basin. During spring they return northwards to the Guinea savannah zone in April and fuel‐up there for the trans‐Sahara passage. At this time they normally increase their body reserves to around 50% of the LBM, but c. 10% of the birds gain 100%, thus doubling their mass. The passage there peaks around 20 April and continues well into May. That the main take‐off northwards is directly from the Guinea savannahs is indicated by the very low numbers trapped in the Sahel during spring.     

Assembly of the Particle of Tobacco Mosaic Virus from RNA and Disks of Protein

The reconstitution of TMV does not proceed by the stepwise addition of single protein subunits, but by the addition of preformed disks to the growing rod. The assembly is initiated by the interaction of a disk with a special sequence of about fifty nucleotides at the 5′ end of the TMV RNA. This is the basis of the selectivity for viral over other RNAs.     

Quantification and characterization of sedimenting particulate organic matter in a shallow hypereutrophic lake*

SUMMARY. Sedimenting seston was collected in May-November 1976 and 1977 in sedimentation traps anchored 0.5 m above the pelagic sediments of hypereutrophic Wintergreen Lake. Sedimentation rates differed greatly in the two years studied, ranging from 2.7 to 19.3 g m^?2 day^?1 in 1976 and from 2.6 to 9.5 g m^?2 day^?1 in 1977. Because of the shallowness of the lake (maximum depth 6.5 m), the quantity and quality of sedimenting particulate organic matter (POM) was closely linked to the production dynamics of the phytoplankton. Chemical analyses indicated that the sedimenting POM was planktonic in origin and, in contrast to that of many deeper lakes, was dominated by protein. Short sedimentation distances coupled with the close proximity of the anaerobic hypolimnion to the photic zone ensured that the majority of sedimenting POM reached the sediments in a relatively undegraded form.