The ventricles of the brain in the N. American mink (Mustela vison (Brisson, 1756))

Using anatomical as well as radiographic and tomographic methods, sixty brains of the N. American mink were examined. It was found that the brain consists of four ventricles. Also, it was noted that the posterior horn was missing and that there was the olfactory recess present in the lateral ventricle, a large-size interthalamic connection present in the third ventricle, and a flat, necklace-like bottom in the fourth ventricle. Only recently, the ins and outs of the mink's anatomical structure have begun to absorb anatomists. Apparently, it is related to the fact that furry animals, among them the mink, are being domesticated as if "before our eyes". For this reason and because of the easy access to material, examining of the brain ventricles in the mink was taken up.     

Phylogenetic characterization of rabies virus isolates from Carnivora in Brazil

The incidence of canine rabies has been widely reported in Brazil, and new rabies virus (RV) variants, genetically similar to canine RV, have recently been isolated from foxes. In order to derive the epidemiological characteristics of Brazilian Carnivora RV, Brazilian RVs isolated from dogs, cats, and foxes were genetically analyzed. Brazilian Carnivora RV isolates were divided into 2 main lineages. The predominant lineage was found in dogs and cats, which included the Argentinean and Bolivian Carnivora RV isolates, and was extensively distributed throughout Brazil and surrounding countries. The other lineage consisted of three sublineages containing Brazilian dog and fox RV isolates, with the dog sublineages located on an internal branch of 2 fox sublineages, suggesting that RV transmission events might have occurred between foxes and dogs in the past. These results suggest that contact between dogs and wildlife has the potential to generate new rabies variants and that it is important to control RV infection cycles in both dogs and wildlife to prevent spread of rabies infection.     

Ripening-related defense proteins in Annona fruit

In order to obtain a better understanding of the active defense strategy of cherimoya (Annona cherimola Mill.) fruit, hydrolytic and antifungal activity, as well as expression of proteins functionally and immunogenically related to the pathogenesis-related proteins chitinase (PR-Q) and 1,3-β-glucanase (PR-2), were estimated in fruit at different ripening stages. Increase in expression of the 27 kDa constitutive chitinase and the induction of two new proteins, a 26 kDa chitinase and a 51 kDa 1,3-β-glucanase were associated with enhanced in vitro hydrolytic and antifungal activity of the acidic protein extract in ripe fruit. Ripening modified the expression of constitutive basic isoenzymes, with a sharp decrease in both relative accumulation and hydrolytic activity. Likewise, a new basic 33 kDa chitinase was induced in the over-ripe fruit, concomitant with accumulation of a basic constitutive 76 kDa 1,3-β-glucanase. At this stage, the basic protein extract modified in vitro growth inhibition of Botrytis cinerea. Short-term high CO₂ treatment delayed fruit ripening and maintained a similar distribution of activity and isoenzymatic pattern in both protein fractions to that in unripe fruit. These results indicate that the changes in the pattern of defense proteins and hydrolytic activity in cherimoyas appear to be associated with ripening. Moreover, unlike the constitutively expressed isoenzymes, only the transitorily induced chitinases and 1,3-β-glucanases were associated with an active defense-related response.     

Untersuchungen zum endophytischen Befall von Fusarium proliferatum (Matsushima) Nirenberg in geernteten Stangen von Spargel (Asparagus officinalis L.)

Zusammenfassung Erstmalig wurden mit den vorliegenden Untersuchungen Spargelstangen zur Haupterntezeit auf endophytischen Pilzbefall untersucht. Sie zeigen, dass im Ernteprodukt zwar Fusarium proliferatum als potenzieller Mykotoxinbildner zu finden ist. Eine mögliche natürliche Kontamination mit Fumonisinen bestätigte sich nicht. Von den mit F. proliferatum infizierten Stangen wies nur eine Stange mit grau-rosa-orange farbenen Gewebeveränderungen an der Basis sichtbare Symptome auf. Allgemeine Rückschlüsse auf eine mögliche Gefährdung oder Nichtgefährdung des Verbrauchers beim Verzehr von mit F. proliferatum kontaminierten, symptomlosen Stangen können aus der Analyse nicht gezogen werden. Hierzu müssen weitergehende Untersuchungen zur Wirt-Pathogen-Interaktion erfolgen und die phänotypischen und genotypischen Einflussfaktoren in diesem Prozess noch näher untersucht werden.     

Artenspektrum und Befallshäufigkeit von Fusarium spp. in Bt- und konventionellem Mais im Maiszünsler-Befallsgebiet Oderbruch

The European corn borer (Ostrinia nubilalis) is one of the most important pests of maize (Zea mays). Injuries to the plants caused by the larvae of the European corn borer may represent entrance gates for fungal-spores. The cultivation of Bacillus thuringiensis maize (Bt-maize) is one possibility to reduce infestation by the European corn borer. The aim of the present project was to determine and to compare the number of species and the frequency of Fusarium spp. infestation in Bt-maize (cry1Ab) and conventional maize. In 2003, we analysed the Fusarium spp. infestation of samples of chaffed Bt-maize and its isogenic variety on two experimental fields in the Oderbruch region (Germany), an European corn borer infested area. The conventional variety on the first of the experimental fields (previous crop wheat and forking cultivation) showed a small infestation (16%) of Ostrinia nubilalis while in the conventional variety on the second field (previous crop maize and not forking cultivation) the infestation of the European corn borer was almost three times higher (47%). In the conventional variety on both of the experimental fields we found a high Fusarium spp. infestation (70%). Especially species of the section Liseola dominates, among them: F. subglutinans, F. proliferatum und F. verticillioides. The Fusarium infestation in the samples of Bt-maize from the field with previous crop wheat and forking cultivation was just as high as in the conventional variety (70%). The infestation of Fusarium spp. in the samples of Bt-maize from the field with previous crop maize and forking cultivation was more than 20?% lower.     

The effects of Douglas-fir on tree-specific arthropod communities in mixed species stands with European beech and Norway spruce

The ecological effects of planting exotic Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] in Central Europe are still poorly understood. The aim of this study was to answer the question of whether Douglas-fir affects tree specific arthropod communities in different mature forest types (Douglas-fir, spruce and beech dominated) in Southern Germany. Therefore, arthropod communities of stem and tree crown strata of Douglas-fir and spruce (Picea abies L.) were sampled in the years 1999–2001 using arboreal photo-eclectors and flight interception traps. Statistical analysis was conducted for all species and focused on conifer specialists at three levels: (1) species diversity, (2) guild structure and (3) community structure. Within the stem stratum, species diversity was significantly higher on spruce than on Douglas-fir independent of year and stand composition. This could not be explained by a single feeding guild, rather by species changing strata during the vegetation period. In contrast, species diversity in tree crowns was approximately the same for both conifer species. However, communities in Douglas-fir crowns were conspicuously different from those in spruce crowns, especially in the Douglas-fir dominated stand type. While zoophagous insects exhibited higher activity on Douglas-fir in 2000, xylophagous beetles were more abundant on spruce in 2001. In European beech stands with widely spaced Douglas-fir trees, the site specific and broad-leaved tree related fauna might be maintained. In addition, Douglas-fir with its resource of Adelges cooleyi and crowns that overtop the broad-leaved tree canopy, offer additional resources for several aphidophagous and thermophile species.     

Fruit load and canopy shading affect leaf characteristics and net gas exchange of 'Spring' navel orange trees

Five-year-old 'Spring' navel (Citrus sinensis (L.) Osbeck) orange trees were completely defruited, 50% defruited or left fully laden to study effects of fruit load on concentrations of nitrogen (N) and carbohydrate, net assimilation of CO2 (Ac) and stomatal conductance (gs) of mature leaves on clear winter days just before fruit harvest. Leaves on defruited trees were larger, had higher starch concentrations and greater leaf dry mass per area (LDMa) than leaves on fruited trees. Both Ac and gs were more than 40% lower in sunlit leaves on defruited trees than in sunlit leaves on trees with fruit. Leaves immediately adjacent to fruit were smaller, had lower leaf nitrogen and carbohydrate concentrations, lower LDMa and lower Ac than leaves on non-fruiting branches of the same trees. Removing half the crop increased individual fruit mass, but reduced fruit color development. Half the trees were shaded with 50% shade cloth for 4 months before harvest to determine the effects of lower leaf temperature (Tl) and leaf-to-air vapor pressure difference on leaf responses. On relatively warm days when sunlit Tl > 25 degrees C, shade increased Ac and gs, but had no effect on the ratio of internal to ambient CO2 (Ci/Ca) concentration in leaves, implying that high mesophyll temperatures in sunlit leaves were more important than gs in limiting Ac. Sunlit leaves were more photoinhibited than shaded leaves on cooler days when Tl < 25 degrees C. Shade decreased total soluble sugar concentrations in leaves, but had no effect on leaf starch concentrations. Shading had no effects on canopy volume, yield or fruit size, but shaded fruit developed better external color than sun-exposed fruit. Overall, the presence of a normal fruit crop resulted in lower foliar carbohydrate concentrations and higher Ac compared with defruited trees, except on warm days when Ac was reduced by high leaf temperatures.     

Effects of selection felling and gap felling on forest arthropod communities: a case study in a spruce-beech stand of southern Bavaria

The effects of selection felling and gap felling on arthropod communities were studied over 3 years in a spruce-beech stand in southern Bavaria, Germany. The arthropods were sampled in three strata, using pitfall traps on the forest floor as well as flight-interception traps near the forest floor and in the tree crowns. Coleoptera, Araneae, Opiliones, Heteroptera, Isopoda, Diplopoda and Neuropterida were determined to species level and assigned to ecological guilds. In general, the effects of both treatments on arthropod communities were small. An increase of eurytopic species and species of open woodland as well as of indwellers of deadwood was observed, mainly in the first year after felling. However, forest species dominated the communities in all plots, strata and years. In contrast to selection fellings, gap fellings might favour potential pest species. Nevertheless, in the studied managed spruce-dominated forest site out of the natural growth range of spruce, negative ecological effects such as the repression of forest arthropod species are not expected by small scale fellings.     

Evaluation of laryngeal function under the influence of various head and neck positions during exercise in 58 performance horses

The objective of this study was to examine laryngeal function at rest and during ridden exercise and to further analyse the impact of different head and neck positions on the laryngeal function in ridden sport horses. Fifty‐eight Warmblood horses were examined endoscopically during ridden exercise as well as during quiet breathing at rest before and after sedation. Four different head‐neck positions (unrestrained, reference, elevation and hyperflexion) were assessed during the exercise test. Laryngeal function was graded at rest and for every combination of gait and head and neck position during exercise. There was a significant correlation between the grade of laryngeal function during exercise and at rest both before (correlation coefficient = 0.794) and after (correlation coefficient = 0.741) sedation (P<0.01). No significant association was found between the grade of laryngeal function during exercise and the different head and neck positions.