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Two Stages of Increased IgA Transfer During Lactation in the Marsupial, Trichosurus vulpecula (Brushtail Possum). What is going on?. Collection of mammary glands from trapped possums Snap freeze mammary glands next day
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Two Stages of Increased IgA Transfer During Lactation in the Marsupial, Trichosurus vulpecula (Brushtail Possum)
What is going on? • Collection of mammary glands from trapped possums • Snap freeze mammary glands next day • Extract RNA fragments corresponding to J protein, C-alpha and pIgR (polymeric Ig receptor) AMPLIFY IT USING PCR!
What they found... • mRNAs for C-alpha, J proteins and pIgR were expressed throughout lactation • Meaning IgA is transferred to milk throughout lactation • But – 2 main periods of increased expression of these genes • 1. At beginning of lactation • 2. At end of switch period (when young grows fur and is about to leave pouch). This is around 106-115 days.
Why? • At both these times, young is about to be exposed to new pathogens • So, it needs protection in form of more IgA.
What's good about it? • Mammary glands frozen as soon as possible, I.e. morning after trapping • Random selection of possums as they have been trapped • The mammary glands collected ranged from day 1 to day 190 of lactation • Testing for presence of these genes is a good way of monitoring IgA transfer into milk
What's bad about it? • There may have been only a few captured possums from a certain lactation period giving us weak evidence. • Only 35 possums were captured – is the sample large enough? • Trapping method may favour certain individuals e.g. those in need of food. • No direct measurement of IgA taken • Unclear aim
Conclusion • Main queries were with sample size and composition i.e. were there enough of each lactation period to get a good valid results? • Overall study had a good conclusion however its difficult to know if they fulfilled the aim of the experiment.