The avian thyroid gland.

There has been a considerable amount of research regarding the function of the avian thyroid gland, particularly in chickens. There is also more information on diseases of the avian thyroid gland, although it is usually in the form of case reports. This article covers a limited amount of material on the structure and function of the avian thyroid gland and its diseases.     

Recurrent spinal arachnoid cyst in a cat

Spinal arachnoid cysts (SACs) are uncommon expanding lesions in the spinal canal. They are rarely diagnosed in dogs, and there are only four published cases in cats. We report a case of a 12-year-old cat with recurrent signs of intermittent urinary incontinence and hind limb ataxia 2 years after surgical marsupialisation of a spinal arachnoid cyst at T11/12. Recurrence of a cyst was diagnosed by myelography. Repeated marsupialisation after laminectomy was successful and the cat recovered satisfactorily although intensive physical therapy was necessary. SACs are very rare in cats and seem to occur mainly as a secondary lesion to spinal and meningeal trauma or irritation due to bony changes of the vertebrae.     

Convergence Amid Divergence in a Region

The convergence hypothesis from neoclassical growth theory is examined for per capita incomes of counties within a large subnational region, the Great Plans. Convergence of the β and σ varieties are considered. The former describes the tendency for economies with low per capita incomes in an initial period to grow faster than those with higher incomes. The latter describes the tendency for the dispersion of incomes to fall over time and eventually stabilize. Total per capita incomes across the region show a β convergence speed over the past quarter century roughly equal to that found for activity measures in previous analyses of nation groups, continental regions, and states of the U.S. As concerns σ convergence, the dispersion of total per capita incomes in the region stabilized during the past decade. However, when transfer payments and dividends, interest, and rents are deducted from income, β convergence speeds drop markedly and the dispersion of incomes rises over the study period.     

Abundance of Iron-Oxidizing Thiobacilli and Biological Sulfur Oxidation Potential from Soil Impacted by Coal and Coal Refuse Piles

This study was conducted to assess the abundance of iron-oxidizing bacteria and biological sulfur oxidation potential from soil impacted by coal and coal refuse from two coal-burning electric power facilities located at the U.S. Department of Energy's Savannah River Site (Aiken, S.C.) and the South Carolina Electric and Gas Site at Beech Island, S. C. Significantly higher MPN counts of iron-oxidizing bacteria were obtained from samples collected at the confluence of a coal storage runoff containment basin, a coal reject (refuse) pile, and an adjacent wetland at the Savannah River Site. Significant differences in pH, sulfate-S, ferrous- and ferric-iron were also obtained between sampling locations. No significant differences in ferric/ferrous ratios were determined. These ratios however, exceeded a value of 2.0 when sample pH values were less than 4.5. Under optimal conditions, biological thiosulfate-S oxidation potentials (in vitro) showed a 4- to 7-day lag in the appearance of sulfate-S, and a final pH (after twenty-four days of perfusion) of 1.97 to 3.90. These results indicate that contamination of subsurface water by acidic leachate derived from thionic bacterial activity will occur if coal and coal refuse piles are not confined by an impermeable surface or containment facility.     

Variation in competitive abilities of plants and microbes for specific amino acids

 Microbes are assumed to possess strong competitive advantages over plants for uptake of nutrients from the soil. The finding that non-mycorrhizal plants can obtain a significant fraction of their N requirement from soil amino acids contradicts this assumption. The amino acid glycine (Gly) has been used as a model amino acid in many recent studies. Our preliminary studies showed that Gly was a poor substrate for microbial growth compared to other amino acids. We tested the hypothesis that the alpine sedge Kobresia myosuroides competes better for Gly than for other amino acids because of decreased microbial demand for this compound. Soil microbial populations that could grow using Gly as a sole carbon source were about 5 times lower than those that could grow on glutamate (Glu). Gly supported a significantly lower population than any of the ten other amino acids tested except serine. In contrast, K. myosuroides took up Gly from hydroponic solution at faster rates than Glu. In plant-soil microcosms, plants competed with soil microbes 3.25 times better for Gly than for Glu. We conclude that the low microbial demand and the rapid plant uptake of Gly relative to other amino acids allow Gly to be an especially important nitrogen source for K. myosuroides. Received: 9 February 1998     

Influence of the chemical environment on metolachlor conformations.

Metolachlor exists in multiple, different stable conformations in solution. Assignment of the NMR frequencies to chemical structure is a prerequisite to understanding the behavior of individual conformations. (1)H NMR experiments of metolachlor in different chemical environments identified the labile sites of metolachlor and environments that influence conformational/configurational changes. Within very specific chemical environments, metolachlor atropisomers aS,12S (aR,12R) and aR,12S (aS,12R) freely interchange, and consequently, the multiple conformations also interchange. The changes in chemical environments, which most alter the conformations and molecular dynamics of metolachlor, identify the most critical components affecting its environmental fate. These results enable a structural interpretation of conformational changes that can influence the environmental fate of metolachlor.     

Avian polyomavirus infection and disease in a green aracaris (Pteroglossus viridis).

Avian polyomavirus (APV) is one of the most significant pathogens of domestically raised psittacine birds (parrots). One or more APVs are suspected to infect nonpsittacine cage birds, but the relationship of these viruses to the APV infecting parrots remains unclear. In this report, for the first time, we fully document an APV infection in a nonpsittacine cage bird, a green aracaris (Pteroglossus viridis). Grossly, this bird evidenced generalized hemorrhage. Histologically, there was severe hepatic necrosis, splenic necrosis, and the presence of lightly basophilic to clear pannuclear inclusion bodies and karyomegaly in splenocytes and renal mesangeal cells, all characteristic lesions of APV infection in parrots. APV DNA was amplified directly from the liver by polymerase chain reaction and sequenced. The virus differed from the original APV sequence by only 24 base pairs (0.48% of the genome), demonstrating that it is a variant of the APV. A serologic survey of the remaining birds in the aviary demonstrated anti-APV antibody in two cockatoos, two cockatiels, a laughing kookaburra, a Lady Ross turaco, and five zebra finches. The remaining green aracaris was seronegative. The sequence and serologic data suggest that the APV that infected the green aracaris originated in a parrot and was capable of infecting birds from at least four orders.     

F?ngigkeit von differenziert bestückten Borkenk?ferpheromonfallen in einem nieders?chsischen Forstgebiet bei Hannover w?hrend der Jahre 1992 und 1993

In den Jahren 1992 und 1993 wurden 24 schwarzeTheysohn-Schlitzfallen mit Kombinationen von synthetischen Borkenk?ferlockstoffen, Pheroprax, Chalcoprax, Linoprax und Cembrax, auf ihre F?ngigkeit getestet. Zum Vergleich wurden Fallen mit Einzelbestückung und Zweifachkombinationen von Pheroprax+Cembrax und Linoprax+Cembrax sowie zwei Fallen ohne Lockstoff in einem 24 ha gro?en Forstgebiet aufgestellt. Mit den Fallen wurde die Flugaktivit?t der angelockten Scolytiden ermittelt. Die erhaltenen Fangzahlen vonIps typographus, Pityogenes chalcographys, Xyloterus lineatus undX. domesticus wurden w?chentlich registriert und in Verbindung mit der unterschiedlichen Pheromonbestückung der Fallen diskutiert. Von den drei letztgenannten Arten wurde der Fang von M?nnchen und Weibchen getrennt bewertet. In einzeln mit Pheroprax bestückten Fallen fanden sich die meisten Buchdrucker pro Falle. Ihr Anteil nahm 1993 um 9% gegenüber dem Vorjahr zu. Für den Kupferstecher waren die vierfach kombinierten Pheromonfallen etwas f?ngiger als die einzeln mit Chalcoprax bestückten Fallen. AuchXyloterus-Arten bevorzugten die vierfach kombinierten Pheromonfallen gegenüber solchen, die nur Linoprax enthielten. Die Anzahl der gefangenen Ambrosiak?fer wurde im Verlauf von 5 Jahren stark reduziert.