Analysis of stomach contents from the black-browed albatross, <Emphasis Type="Italic">Thalassarche melanophris</Emphasis>, on the Coast of Rio Grande do Sul,Southern Brazil

The black-browed albatross, Thalassarche melanophris, travels along the southern coast of Brazil during migration. Their numbers appear to have decreased in recent years. From July 1997 to 1998, we carried out monthly surveys on the coast of Rio Grande do Sul, Southern Brazil, to count albatrosses in the area and identify ingested items. We found 85 dead specimens of T. melanophris, from which 35 stomachs were collected and the contents analyzed. Nearly 6% of the stomachs contained fish, 32% contained cephalopods and 9% contained crustaceans. About 69% of the stomachs contained nematodes and nematomorphs. The highest abundance values found per stomach was 182 nematode individuals and 223 nematomorph individuals. Synthetic materials were present in 29% of the stomachs analyzed, comprising thermoplastic, nylon, rubber and metal wire.     

Chemotaxonomic significance of flavonoids and phenolic acids in the Hieracium rohacsense group (Hieracium sect. Alpina; Lactuceae, Compositae)

Five apomictic taxa from the Hieracium rohacsense group were studied for their phenolic constituent composition. The following substances represent dominant compounds in the leaves: chlorogenic acid, 3,5-dicaffeoylquinic acid, luteolin 7-O-β- -glucopyranoside, luteolin 4′-O-β- -glucuronopyranoside and apigenin 4′-O-β- -glucuronopyranoside. Within the group only quantitative differences were found, luteolin 7-O-glucoside being the most important chemotaxonomic marker. Each taxon has its own specific quantitative pattern, invariable within the taxon. Based on these characteristic profiles, H. rohacsense can be distinguished from a closely related and still undescribed taxon from Mt. Pip Ivan. The proportion of luteolin 7-O-glucoside to apigenin 4′-O-glucuronoside also clearly separates the individuals of two morphologically close species—H. ratezaticum and H. pseudocaesium, which corresponds to a few slight but recognisable morphological and phenological characteristics. The ontogenetic stage of leaf development and seasonal variation are also important factors, which must be taken into consideration, as the quantity of the substances changes during leaf ontogeny and with season.     

Non-Hemagglutinating Flaviviruses: Molecular Mechanisms for the Emergence of New Strains via Adaptation to European Ticks

Tick-borne encephalitis virus (TBEV) causes human epidemics across Eurasia. Clinical manifestations range from inapparent infections and fevers to fatal encephalitis but the factors that determine disease severity are currently undefined. TBEV is characteristically a hemagglutinating (HA) virus; the ability to agglutinate erythrocytes tentatively reflects virion receptor/fusion activity. However, for the past few years many atypical HA-deficient strains have been isolated from patients and also from the natural European host tick, Ixodes persulcatus. By analysing the sequences of HA-deficient strains we have identified 3 unique amino acid substitutions (D67G, E122G or D277A) in the envelope protein, each of which increases the net charge and hydrophobicity of the virion surface. Therefore, we genetically engineered virus mutants each containing one of these 3 substitutions; they all exhibited HA-deficiency. Unexpectedly, each genetically modified non-HA virus demonstrated increased TBEV reproduction in feeding Ixodes ricinus, not the recognised tick host for these strains. Moreover, virus transmission efficiency between infected and uninfected ticks co-feeding on mice was also intensified by each substitution. Retrospectively, the mutation D67G was identified in viruses isolated from patients with encephalitis. We propose that the emergence of atypical Siberian HA-deficient TBEV strains in Europe is linked to their molecular adaptation to local ticks. This process appears to be driven by the selection of single mutations that change the virion surface thus enhancing receptor/fusion function essential for TBEV entry into the unfamiliar tick species. As the consequence of this adaptive mutagenesis, some of these mutations also appear to enhance the ability of TBEV to cross the human blood-brain barrier, a likely explanation for fatal encephalitis. Future research will reveal if these emerging Siberian TBEV strains continue to disperse westwards across Europe by adaptation to the indigenous tick species and if they are associated with severe forms of TBE.     

Phytodetoxification of the environmental pollutant and explosive 2,4,6-trinitrotoluene

Our recent study highlights the role of 2 glutathione transferases (GSTs) in the detoxification of the environmental pollutant, 2,4,6-trinitrotoluene (TNT) in Arabidopsis thaliana. TNT is toxic and highly resistant to biodegradation in the environment, raising both health and environmental concerns. Two GSTs, GST-U24 and GST-U25, are upregulated in response to TNT treatment, and expressed predominantly in the root tissues; the site of TNT location following uptake. Plants overexpressing GST-U24 and GST-U25 exhibited significantly enhanced ability to withstand and detoxify TNT, and remove TNT from contaminated soil. Analysis of the catalytic activities of these 2 enzymes revealed that they form 3 TNT-glutathionyl products. Of particular interest is 2-glutathionyl-4,6-dinitrotoluene as this represents a potentially favorable step toward subsequent degradation and mineralization of TNT. We demonstrate how GSTs fit into what is already known about pathways for TNT detoxification, and discuss the short and longer-term fate of TNT conjugates in planta.     

Evidence of food items used by <Emphasis Type="Italic">Fulmarus glacialoides</Emphasis> (Smith 1840) (Procellariiformes: Procellariidae) in Southern Brazil

Monitoring trips were conducted along the coast of the state of Rio Grande do Sul, Brazil from July 1997 to July 1998 to contribute toward knowledge on the feeding habits of Fulmarus glacialoides during migration. Five hundred and sixty two carcasses of F. glacialoides were found, 42 of which were in adequate conditions for collection and subsequent stomach content analysis. All stomach revealed the remains of cephalopods. The following were identified from the 60 lower beaks of cephalopods found: Sepidae, Histioteuthis sp., Discoteuthis sp., Chiroteuthis sp., Mesonychoteuthis hamiltoni, Lycoteuthis sp., Lycoteuthis lorigera, Ancistrocheirus lesueuri, Alluroteuthis antarctica, Loligo plei and Argonauta nodosa. Histioteuthis sp. was found in 70% of stomachs analyzed, with a mean biomass of 53 g. Fish were identified through otoliths and were found in the stomach contents of two specimens. Elytra from insects were found in the contents of eight stomachs, at least 20 of which were coleopterans. A Belostomatidae was found in the contents of one stomach.     

Augmentative biological control of arthropods in Latin America

Augmentative forms of biological control, wherenatural enemies are periodically introduced,are applied over large areas in variouscropping systems in Latin America. About 25%of the world area under augmentative control issituated in this region. Well-known examplesare the use of species of the egg parasitoidTrichogramma for management ofLepidoptera in various crops. In Mexico, forexample, about 1.5 million hectares are treatedwith Trichogramma spp. Application ofTrichogramma also occurs on large areasin Colombia and Cuba, but use is limited inother Latin American countries for economicreasons, the generally low level of educationof farmers, and, more importantly, because ofthe intensive use of pesticides that preventsuse of natural enemies. Of the other eggparasitoids, the main species used incommercial releases are Trissolcusbasalis (Wollaston) against the heteropteranNezara viridula (L.) in soybean inBrazil, and Telenomus remus Nixon againstSpodoptera frugiperda (J.E. Smith) incorn in Venezuela. Natural enemies attackinglarval and pupal stages are not used to a largeextent in augmentative biological control infield crops, with the exception of the use ofCotesia parasitoids against sugarcaneborers in Brazil and several other LatinAmerican countries. In addition to the use ofparasitoids and predators, Latin America isapplying microbial control agents on a largescale, such as viruses for control ofcaterpillars in soybean, fungi for control ofpests in coffee, cotton and sugar cane, andnematodes for control of soil pests. A recentdevelopment in biological control in LatinAmerica is the use of natural enemies andantagonists for disease and pest control inprotected cultivation, for example, inColombia, Brazil and Peru. Up to date, reliablefigures on current use of inundative andseasonal inoculative biological controlappeared hard to obtain, but it is clear thatLatin America currently is a main player in thefield of augmentative releases.     

Does predator abundance influence species diversity of equilibrium macroinvertebrate assemblages in spring fens?

1. Predation may significantly control number and density of coexisting species. The effects of predation on species diversity have traditionally been tested in experiments and theoretical models of simple trophic systems. In complex natural ecosystems, however, disentangling multiple sources of variation is difficult. In groundwater-fed environments, a significant effect of predation can be expected due to the relatively stable environmental conditions; however, it has never been properly examined.
2. We analysed species diversity and total abundance of macroinvertebrate assemblages in 48 Western Carpathian spring fens, separately for whole sites and mesohabitat/season, and partitioned the effects of predation intensity from those of environmental variables in robust models using a bootstrapping technique. We verified our results by accounting for taxa resistant to predation.
3. The assumption that predation-mediated coexistence of species is the main mechanism responsible for the relatively species-rich assemblages in the Western Carpathian spring fens was not supported. However, predation may significantly influence abundance of non-predatory species and, under some conditions, it may contribute to explaining patterns in species diversity.
4. The effect of predation did not differ between the mesohabitats with different stability. However, we found higher environmental control in spring and a stronger effect of predators in autumn, which suggests that different mechanisms influence fen assemblages in different seasons.
5. Our study provides a new robust approach how to test the effect of predation on natural macroinvertebrate assemblages. The importance of predation was lower than expected in equilibrium assemblages but it may vary in time.

     

The Stability of Solubilized Mammalian Muscle Acetylcholine Receptors During Purification by Monoclonal Immunoadsorption

The stability of nicotinic acetylcholine receptors (AChR) solubilized from mammalian skeletal muscle in nonionic detergent was investigated under various conditions of pH, chaotropic ions, and unfolding reagents in order to allow its purification in high yield by immunoadsorption to monoclonal antibodies. Preservation of the antigenicity and/or binding sites for alpha-bungarotoxin was used as an indicator of the receptor protein's integrity. Both were preserved in the pH range 6.5-8.0, but when exposed for 1 h at 4 degrees C to a pH outside this range, greater than 50% activity was lost. Of the chaotropic ions studied (NaSCN, NaI, NaNO3, NaCl), only NaCl was tolerated. Most of the AChR's toxin-binding activity was preserved after exposure to 2 M NaCl, which was suitable for dissociating AChR when a monoclonal antibody with relatively low binding affinity was selected as the immunoadsorbent. Yields of purified AChR were optimal (30%) when a low amount of monoclonal antibody was coupled to cyanogen bromide-activated agarose (1 mg protein/ml gel).