Purification of secretory immunoglobulin A from milk of the brushtail possum (Trichosurus vulpecula)

AIM: To identify and purify secretory immunoglobulin A (sIgA), a key effecter molecule in mucosal immune responses, from milk of the brushtail possum (Trichosurus vulpecula).

METHODS: Milk samples were collected from female possums with pouch young, and clarified by centrifugation and precipitation methods. The clarified fraction was purified by gel filtration and affinity chromatography to yield sIgA. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting techniques were used to assess the purity of the final product, and to identify the heavy (H) chain, light (L) chain and secretory component (SC) of possum sIgA.

RESULTS: Immunoblotting, using antibodies raised against cloned possum sIgA SC and H-chain, and a synthetic peptide fragment of the H-chain, confirmed the identity of the purified protein. The N-terminal amino acid sequence of purified possum sIgA showed strong homology to reported sequences of H-chain variable regions of marsupial immunoglobulins.

CONCLUSIONS: Milk was shown to be a convenient source of mucosal secretion containing sIgA, and a process involving 2 precipitation and 2 chromatography steps produced purified sIgA. This IgA preparation will prove useful for the generation of sIgA-specific immunological reagents for measurement of immune responses in the development of mucosal-based vaccines for biological control of possums.     

Listeria monocytogenes gastroenteritis in sheep

Extract

Listeria monocytogenes is widely distributed in the environment of farm animals. It is found in soil, faeces and nasal secretions of healthy animals, water troughs and animal feeds. Under certain conditions it becomes pathogenic, causing serious disease in cattle and sheep. Most commonly it causes meningoencephalitis but, on occasion, septicaemic listeriosis results in abortion, and more recently it has been associated with gastroenteritis.     

The structure of the upper atmosphere of mars: In situ accelerometer measurements from mars global surveyor

The Mars Global Surveyor (MGS) z-axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared to only three previous such vertical structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large thermospheric response at mid-northern latitudes, increasing the altitude of thermospheric pressure surfaces there by as much as 8 kilometers and indicating a strong global thermospheric response to a regional dust storm. Throughout the MGS mission, thermospheric density bulges have been detected on opposite sides of the planet near 90 degreesE and 90 degreesW, in the vicinity of maximum terrain heights. This wave 2 pattern may be caused by topographically-forced planetary waves propagating up from the lower atmosphere.     

Mass spectrometric techniques as aids in the diagnosis of gangrene in potatoes caused by Phoma exigua var. foveata

Current diagnosis of gangrene in potato tubers, caused byPhoma exigua var.foveata, is based on isolation and identification of the causal organism or on thin-layer chromatographic (TLC) detection of the anthraquinone pigment pachybasin (1-hydroxy-3-methylanthraquinone). In this paper alternative diagnostic approaches are described based on detection of specific ions by pyrolysis mass spectrometry (Py-MS), direct probe mass spectrometry (DIP-MS) and gas chromatography-mass spectrometry (GC-MS). The advantages and disadvantages of these methods are discussed in comparison with the TLC approach. GC-MS is a promising technique because of its high specificity, sensitivity and suitability for automation. Moreover, the MS approaches may lead to a reduction of total expertise time.Samenvatting De huidige diagnostiek van gangreen in aardappelknollen, veroorzaakt doorPhoma exigua var.foveata, is gebasserd op de isolatie en identifikatie van de schimmel of op de dunnelaag-chromatografische (TLC) bepaling van het pigment pachybasine (1-hydroxy-3-methylanthrachinon).In dit artikel worden nieuwe diagnostische benaderingen beschreven die gebaseerd zijn op de detectie van specifieke ionen door middel van pyrolyse-massaspectrometrie (Py-MS), direct-probe-massaspectrometrie (DIP-MS) en gaschromatografie-massaspectrometrie (GC-MS). De voor- en nadelen van deze methoden worden behandeld en vergeleken met de dunnelaag-chromatografische methode.GC-MS is een veelbelovende methode vanwege de grote specificiteit, gevoeligheid en geschiktheid voor automatisering. Op den duur kunnen de MS-methoden leiden tot een verkorting van de totale expertisetijd.