Using a GnRH agonist to obtain an index of testosterone secretory capacity in the cockatiel (Nymphicus hollandicus) and sulphur-crested cockatoo (Cacatua galerita)

Objective   Validation of a stimulation test for determining the steroidogenic capacity of the parrot testis. The major aim was to characterise testosterone secretion after injection of a gonadotropin-releasing hormone agonist (GnRHa), then use the test to investigate seasonal reproduction in the male cockatiel.
Procedure   A synthetic GnRHa (buserelin; 8.0 µg of peptide/kg bodyweight) was injected IM into male cockatiels (n = 7) and sulphur-crested cockatoos (n = 3) and serial blood samples collected at 0, 30, 60, 90 and 120 min after administration. Once validated, the technique was subsequently used to examine seasonal changes (23 months) in the testosterone profile of a captive cockatiel population.
Results   Injection of buserelin resulted in a significant increase in the testosterone concentration of cockatiel plasma, with maximal concentrations occurring at approximately 60 (1.33 ± 0.08 ng/mL) to 90 min (1.22 ± 0.08 ng/mL) after injection. Although no clear pattern of seasonal variation in testosterone secretion was detected in cockatiel plasma, samples taken 60 and 90 min after administration showed a significant increase in all seasons. Injection of buserelin in the sulphur-crested cockatoo also resulted in increased testosterone secretion, with maximal concentrations obtained after 90 min.
Conclusion   Buserelin can be used to obtain a reliable index of the prevailing testosterone capacity of the cockatiel and cockatoo testis. With further studies, this test may be incorporated into clinical assessment of reproductive status.     

Untersuchungen zum Auftreten von Pathogenen beiIps typographus L. (Coleoptera,Scolytidae) aus einem Naturschutzgebiet im Schwarzwald (Baden-Württemberg)

Zusammenfassung Die permanenten Probleme mit dem großen achtzähnigen Fichtenborkenkäfer,Ips typographus L., in mittel- und nordeuroäischen Fichtenwäldern waren der Anlaß für qualitative und quantitative Erhebungen zum Pathogen-Komplex bei dieser Borkenkäfer-Art von einem außeralpinen Standort in SW-Deutschland. Zu diesem Zweck wurden erwachsene Käfer in Einzelsektionen im Lichtmikroskop untersucht. Zusätzlich wurde das Käfer-Geschlecht bestimmt. Bei der Auswertung wurden drei Untersuchungsgruppen unterschieden: 1. Käfer, vor dem Schlüpfen (aus den Rinden herausgelöst), 2. Käfer, die in der ersten Schlüpfwoche- und 3. Käfer, die in der zweiten Schlüpfwoche selbsttätig geschlüpft waren.Bei den Untersuchungen konnten neben den bereits bekannten Pathogen-Arten, demI. typographus-Entomopoxvirus, den MicrosporidienChytridiopsis typographis, Nosema typographi undGregarina typographi auch ovale Sporen gefunden werden, bei denen es sich vermutlich um Neogregarinen handelt. An Parasiten konnten die NematodenContortylenchus diplogaster undCryptaphelenchus macrogaster macrogaster sowie in einem Fall Hymenoptern-Larven der ArtTomicobia seitneri gefunden werden. Bei den drei Untersuchungsgrappen konnten zum Til beträchtliche Unterschiede in der Häufigkeit der einzelnen Pathogen-Arten beobachtet werden. So war die Anzahl der Pathogene, bei den selbsttätig geschlüpften Käfern erheblich höher als bei jenen, die aus den Rinden herausgelöst worden waren. Darüber hinaus war die Anzahl infizierter Käfer in der zweiten Schlüpfwoche nochmals deutlch höher als in der ersten. Ebenso war die Anzahl infizierter männlicher Käfer meist größer als die der weiblichen Käfer.Die Ergebnisse werden mit früheren Untersuchungen beiI. typographus von Standorten aus den Kern- und Randgebieten der Ostalpen in Österreich sowie solchen aus der tschechischen Republik verglichen. Die Verbreitung und Häufigkeit der Pathogene wird aus der Sicht ihrer möglichen Wirkung diskutiert.

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Occurrence of pathogen species was qualitatively and quantitatively investigated inIps typographus L. from a nature reserve in the Schwarzwald (Germany). Adult beetles were dissected and examined in a light microscope. Beetles were differentiated by their sex, pathogen frequency was determined seperately in beetles that had been cut out of the bark (before their emergence) or in beetles that emerged normally from the bark. The study revealed the evidence of theI. typographus-Entomopoxvirus and the microsporidiaChytridiopsis typograpbik, Nosema typographi andGregarina typographi. Furthermore, unknown spores could be found which are presumed to belong to the Neogregarine group. Parasitic nematodes (Contortylenchus diphogaster andCryptaphelenchus macrogaster macrogaster) and larvae of the parasitic HymenopteraTomicobia seitneri could be found too.Frequency of pathogens was highest in the late emerging beetles in comparison with the early emerging beetles and especially in comparison with the beetles cut out of the bark. Male beetles showed higher infection rates than female beetles in most cases. Results are discussed with regard to former studies in Austria and in the Czech Republic. Prevalence and frequency of pathogens are explained by the possible efficacy of the distinct pathogen species.

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Mit 3 Tabellen     

Detection of Lyman agr Emission from the Saturnian Disk and from the Ring System

A rocket-borne spectrograph detected H I Lyman alpha emission from the disk of Saturn and from the vicinity of the planet. The signal is consistent with an emission brightness of 700 rayleighs for the disk and 200 rayleighs for the vicinity of Saturn. The emission from the vicinity of the planet may be due to a hydrogen atmosphere associated with the saturnian ring system.     

Immune-mediated hemolytic anemia and thrombocytopenia in a foal

A one-month-old Quarter Horse filly had unilateral epistaxis, hyphema, icterus, petechial hemorrhages in the oral, nasal, conjunctival, and vulvar mucous membranes, anemia, thrombocytopenia, negative antinuclear test result, and a positive direct Coombs' test result. Megakaryocytes or cell-associated IgG (fluorescent antibody and immunoperoxidase stains) were not found in bone marrow biopsy specimens. Treatment consisted of glucocorticoids, antibiotics, and a single whole blood transfusion. The foal responded well to treatment, did not develop relapses of the disease, and was clinically normal one year after treatment.     

Erythrocyte macrocytosis in feline leukemia virus associated anemia

Using erythrocyte volume distribution histograms (erythrograms), erythrocyte macrocytosis and anisocytosis were quantitated in 139 cats tested for feline leukemia virus group-specific antigen. Feline leukemia virus-negative cats with non-regenerative anemia or normal packed cell volumes had normal mean corpuscular volume values. Uninfected cats with regenerative anemia had prominent significantly increased macrocytosis and anisocytosis (p less than 0.01). Ninety percent of 62 feline leukemia virus-positive cats had altered erythrograms. Thirty-three feline leukemia virus-positive cats with non-regenerative anemia had marked macrocytosis. Their mean corpuscular volume values (mean 60 fl +/- 2 fl standard error, reference range of 37-49 fl) were significantly greater than those of feline leukemia virus-negative cats except for those with regenerative anemia. Feline leukemia virus-positive, non-anemic cats had significantly increased mean corpuscular volume values of intermediate magnitude. Nine adult cats experimentally infected with feline leukemia virus developed non-regenerative anemia with significant increases in mean corpuscular volume and anisocytosis. However, the macrocytosis observed in these cats was considerably less than in naturally occurring feline leukemia virus-positive cats with non-regenerative anemia. These observations indicate there are events in the pathogenesis of feline leukemia virus-associated anemia other than simple erythroid hypoplasia. We suggest that hemolysis and erythrocyte regeneration occur before erythroid hypoplasia and may partially account for macrocytosis observed in the face of non-regenerative anemia.     

Segmental axonopathy of Merino sheep in New Zealand

AIM: To investigate an axonopathy of Merino sheep that caused progressive hindlimb ataxia and slight to moderate paresis, with the purpose of understanding its pathogenesis.

METHODS: Tissues were fixed in buffered paraformaldehyde or paraformaldehyde and glutaraldehyde, processed into wax and epoxy resin, respectively, and examined by light and electron microscopy. Fresh frozen spinal cord and trigeminal nerve roots were subjected to homogenisation, centrifugation and two-dimensional electrophoresis. Selected protein spots were identified using matrix-assisted laser desorption ionisation (MALDI) mass spectrometry.

RESULTS. By light microscopy, there were large pale foamy spheroidal axonal swellings affecting peripheral as well as central axons. By electron microscopy, these were shown to contain many membrane-bound vesicles. The main abnormalities in expressed proteins involved cytoskeletal elements and myosin heavy chain, the latter interpreted as associated with the molecular motor myosin Va.

CONCLUSIONS: The disorder is the same as that described in Merinos in Australia as segmental axonopathy, and believed to have an inherited aetiology. The lesions and protein changes indicate abnormalities of the cytoskeleton, its relationship with the myelin sheath, and myosin Va molecular motor. The consequence appears to be abnormal axonal transport and inability to maintain the integrity of axons and their myelin sheaths.     

The theropod ancestry of birds: new evidence from the late cretaceous of madagascar

A partial skeleton of a primitive bird, Rahona ostromi, gen. et sp. nov., has been discovered from the Late Cretaceous of Madagascar. This specimen, although exhibiting avian features such as a reversed hallux and ulnar papillae, retains characteristics that indicate a theropod ancestry, including a pubic foot and hyposphene-hypantra vertebral articulations. Rahona has a robust, hyperextendible second digit on the hind foot that terminates in a sicklelike claw, a unique characteristic of the theropod groups Troodontidae and Dromaeosauridae. A phylogenetic analysis places Rahona with Archaeopteryx, making Rahona one of the most primitive birds yet discovered.     

Gut sugar analysis in field-caught parasitoids: Adapting methods originally developed for biting flies

The ability to determine the presence and identity of sugars in the guts of adult parasitoids in the field would aid researchers in addressing long-standing problems in parasitoid ecology. Until very recently, however, gut sugar analyses have not been carried out on parasitoids. This is despite the development and use of methodologies for gut sugar analyses in biting flies (mosquitoes, sand-flies, black-flies, horse- and deer-flies, and biting midges) for decades. Methods used have been the cold anthrone test for the detection of gut sugars, and various forms of chromatography for the identification of gut sugars. We review the use of these methods in biting fly research and then describe the nascent field of gut sugar analyses in parasitoids. Both cold anthrone and chromatography tests have begun to be used on field-caught parasitoids, and we describe progress from our own work. We used cold anthrone on the aphid parasitoid Aphelinus albipodus (Hymenoptera: Aphelinidae), and results from one field study show that approximately one-fifth of individuals tested were positive for gut sugars. The characteristics of the field site point to the primary source of these gut sugars as being aphid honeydew. We also analysed the gut contents of Diadegma insulare (Hymenoptera: Ichneumonidae), a parasitoid of diamondback moth. In this case, HPLC analyses showed that over 85% of field-captured individuals had fed upon sugars. These same analyses suggested that honeydew may have been a major source of the gut sugars in this case also, but the sugar profiles suggest some nectar feeding. Understanding the importance of various sugar sources on parasitoid activity and effectiveness will facilitate the incorporation of sugar sources in habitat manipulation programmes as a part of IPM.