Die Siedlungsdipterologie im Rahmen der modernen Umweltforschung

Zusammenfassung In der vorliegenden Arbeit wird der zahlenmäßige Dipteren-Artenbestand verschiedener Teilbezirke des ländlichen und städtischen Siedlungsbereiches besprochen und ganz allgemein auf die Bedeutung dort in der unmittelbaren Umgebung des Menschen und seiner Nutztiere vorkommender heimischer Dipteren als Gesundheits- und sonstige Schädlinge hingewiesen, woraus sich die Notwendigkeit siedlungsdipterologischer Untersuchungen im Rahmen der modernen Umweltforschung ergibt.

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Summary The present publication reflects on the species of Diptera in different divisions of the rural and municipal sphere of settlements. The importance of native Diptera to insanitary and other noxious is described.

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Der hier aus praktischen Gründen geprägte Begriff Siedlungsdipterologie soll auf die ausschließliche Siedlungsbezogenheit der Untersuchungen hinweisen. Das bei diesen Untersuchungen berücksichtigte Dipteren-Material wurde in Räumen und an Substratlagerplätzen mit dem Netz, Saugrohr oder auch mit Köderfallen gefangen.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Land cover,riparian zones and instream habitat influence stream fish assemblages in the eastern Amazon

The Amazon rainforest has experienced rapid land‐use changes over the last few decades, including extensive deforestation that can affect riparian habitats and streams. The aim of this study was to assess responses of stream fish assemblages to deforestation and land cover change in the eastern Amazon. We expected that percentage of forest in the catchment is correlated with local habitat complexity, which in turn determines fish assemblage composition and structure. We sampled 71 streams in areas with different land uses and tested for relationships between stream fish assemblages and local habitat and landscape variables while controlling for the effect of intersite distance. Fish assemblage composition and structure were correlated with forest coverage, but local habitat variables explained more of the variation in both assemblage composition and structure than landscape variables. Intersite distance contributed to variance explained by local habitat and landscape variables, and the percentage of variance explained by the unique contribution of local habitat was approximately equivalent to the shared variance explained by all three factors in the model. In these streams of the eastern Amazon, fish assemblages were most strongly influenced by features of instream and riparian habitats, yet indirect effects of deforestation on fish assemblage composition and structure were observed even though intact riparian zones were present at most sites. Long‐term monitoring of the hydrographic basin, instream habitat and aquatic fauna is needed to test for potential legacy effects and time lags, as well as assess species responses to continuing deforestation and land‐use changes in the Amazon.     

In vitro gastrointestinal digestion study of two wheat cultivars and evaluation of xylanase supplementation

Background

The filamentous fungus Talaromyces versatilis is known to improve the metabolizable energy of wheat-based poultry diets thanks to its ability to produce a pool of CAZymes and particularly endo-β(1,4)-xylanases. In order to appreciate their in vivo mode of action, the supplementation effect of two of its xylanases, XynD and XynB from families GH10 and GH11 respectively, have been evaluated on two different wheat cultivars Caphorn and Isengrain, which were chosen amongst 6 varieties for their difference in non starch polysaccharides content and arabinoxylan composition.

Results

Polysaccharides digestion was followed during 6 h along the digestive tract using the TNO gastrointestinal model-1, to mimic monogastric metabolism. Polysaccharide degradation appeared to occur mainly at the jejunal level and was higher with Isengrain than with Caphorn. For both cultivars, XynD and XynB supplementation increased notably the amount of reducing end sugars into the jejuno-ileal dialysates, which has been confirmed by a valuable increase of the soluble glucose into the jejunal dialysates.

Conclusions

The amounts of arabinose and xylose into the dialysates and ileal deliveries increased consequently mainly for Caphorn, suggesting that XynD and XynB supplementation in wheat-based diet could alleviate the anti-nutritional effects of arabinoxylans by limiting the physical entrapment of starch and could increase the available metabolizable energy.     

A radiographic stress technique for evaluation of coxofemoral joint laxity in dogs

OBJECTIVE: To develop a radiographic stress technique to quantify hip joint laxity in dogs. STUDY DESIGN: Prospective study on client-owned dogs presented for hip dysplasia screening. ANIMAL POPULATION: 302 nonselected dogs (63 breeds). METHODS: Dogs were sedated and placed in dorsal recumbency. During pelvic radiography, the femoral heads were displaced manually in a craniodorsal direction. On these stress radiographs, the degree of lateral displacement of the femoral heads was assessed in terms of a subluxation index (SI) and compared with the degree of femoral head subluxation and the severity of hip dysplasia found on conventional extended hindlimb radiographs. RESULTS: The degree of subluxation on stress radiographs was significantly greater than on conventional radiographs. Correlation between the severity of canine hip dysplasia (CHD), graded according to conventional techniques, and the degree of subluxation, induced by radiographic stress technique, was positive (r = .57; P<.0001). Two critical SI values were noted. Of the dogs with an SI value of 0.3 or less, 99% were classified as CHD grade normal, borderline, or mildly dysplastic. In dogs with an SI value between 0.3 and 0.5, CHD grading ranged from normal to severely dysplastic. Of the dogs with an SI value greater than 0.5, 95% had dysplastic hip joints. CONCLUSIONS: Hip joint laxity cannot be quantified precisely on standard position radiographs. The proposed stress technique yields significantly higher degrees of femoral head subluxation than the standard position.     

Teat canal closure in non-lactating heifers and its association with udder health in the consecutive lactation

Prevention of heifer mastitis is a key element in preventing mastitis. Since pathogenesis of heifer mastitis is not fully understood yet, combating it is arduous. The goal of this study was to examine whether the premature loss of the keratin plug of the teat canal represents an important risk factor for the development of heifer mastitis. 84 dairy heifers (German Holstein) from six high-yielding dairy herds in Northern Germany were examined between March 2005 and June 2006. Each quarter was examined clinically at least three times before calving. If the teat canal of a quarter was open, secretion samples were collected for bacteriological analysis. After calving, four quarter samples were collected during the first lactation. A rapid increase of the proportion of open teat canals was detected in the preparturition period. No teat canals were open till 80 days before parturition, while 60% of the teat canals were open at 60 days before parturition. A time-scheduled infection pattern was observed: during the days 90-61, 60-31, and 30-0 before calving, skin inhabitants (coagulase-negative staphylococci, coryneform bacteria), cow-related, and environment-related microorganisms prevailed, respectively. A total of 77% of intramammary infections encountered at parturition had established previously. No significant association between the duration of open teat canals before calving and the udder health post partum was found. However, the incidence of clinical mastitis during first lactation was influenced largely by the duration of infection ante partum and the mastitis pathogen involved. This study shows that a high proportion of teat canals already opens several months before calving and that opening of the teat canal before calving is an important factor in the aetiology of heifer mastitis.     

Mutationsversuche an Kulturpflanzen IV. Über den züchterischen Wert zweier röntgeninduzierter nacktkörniger Gerstenmutanten

Zusammenfassung Anschließend an Bemerkungen zur allgemeinen Bedeutung der Nacktgerste, zu Fragen ihrer Züchtung u. dgl. werden die Ergebnisse mehrjähriger Untersuchungen und Beobachtungen an zwei röntgeninduzierten nacktkörnigen Sommergerstenmutanten mitgeteilt.Feld- und brautechnische Bonitierungsdaten sowie andere Beobachtungen ergeben weitgehende Übereinstimmung aller erfaßten Merkmale und Eigenschaften zwischen den Mutanten und ihren Ausgangssorten, mit Ausnahme des nackten bzw. bespelzten Korns. Drei- bzw. zweijährig durchgeführte Leistungsprüfungen erweisen unter Berücksichtigung des Spelzenanteils etwa die gleiche quantitative Leistung bei Mutanten und Ausgangssorten. Nach früheren und neuesten Fütterungsversuchen anderer Autoren mit Nacktgerste sind für die Mutanten gegenüber den Ausgangssorten höhere Nährstofferträge je Flächeneinheit zu erwarten. Die Mutanten dürften ein höheres Leistungsvermögen besitzen als andere Nacktgersten.Kreuzungen der Mutanten mit Nacktgersten des Weltsortiments, u. a. auch solchen aus Abessinien, sowie mit ihren Ausgangssorten zeigen, daß für beide Mutationen ein monomer rezessiver Erbgang und für alle in den Kreuzungen verwendeten nackten Formen Identität des Nacktfaktors vorliegt.Die Untersuchungen lassen keine Rückschlüsse auf eine das Ertragsvermögen reduzierende pleiotrope Wirkung des mutativ entstandenen Allels für Nacktkörnigkeit zu. Unter der Voraussetzung, daß neben der Identität der Loci auch eine solche der Allele bei Mutanten und natürlichen Nacktgersten besteht, kann das bisher nur allmähliche Fortschreiten der Nacktgerstenzüchtung nicht durch eine derartige Pleiotropie des Nacktfaktors bedingt sein. Die Nacktgerstenzüchtung dürfte daher durchaus nicht aussichtslos sein, jedoch deuten ihre Schwierigkeiten auf Koppelung des Nacktfaktors mit ungünstigen Genen.Für derartige Fälle, in denen die Einkreuzung bestimmter Faktoren aus Primitivformen in Zuchtsorten mit Schwierigkeiten verbunden ist, wird die experimentelle Mutationsauslösung als besonders aussichtsreiche Methode angesehen.