A colostrum trypsin inhibitor gene expressed in the Cape fur seal mammary gland during lactation

Trypsin-Inhibitor-Aktivität im Kolostrum – eine Übersicht

Die wichtige Rolle von Kolostrum für das Immunsystem des Neonaten ist lange bekannt. Proteine und vor allem Immunglobuline müssen nach der Aufnahme den Verdauungstrakt mit seinen proteolytischen Enzymen intakt passieren, um in den neonatalen Kreislauf aufgenommen werden zu können. Aus diesem Grund weist Kolostrum eine trypsininhibitorische Aktivität auf. Die Anti-Trypsin-Aktivität wird dabei nicht nur von einem einzigen Molekül getragen, sondern ist eine generelle Eigenschaft des Erstkolostrums. Bei Paarhufern lässt sich eine hohe Trypsin-Inhibition nachweisen, die in den ersten Tagen der Laktation stark abfällt. Auch beim Pferd ist eine Trypsin-Inhibition im Kolostrum festzustellen. Die Bedeutung wird in der Literatur kontrovers diskutiert, weil die Anti-Trypsin-Aktivität im Vergleich zu den Klauentieren geringer ausgeprägt ist und weniger Stabilität im sauren Milieu zeigt. Im Kolostrum von Fleischfressern findet sich ebenfalls eine Anti-Trypsin-Aktivität, die jedoch weniger stark ausgeprägt ist als bei den Huftieren. Diese Literaturübersicht hat zum Ziel, das bekannte Wissen zur Anti-Trypsin-Aktivität im Kolostrum verschiedener Spezies zusammenzufassen.

Marsupial milk: a fluid source of nutrition and immune factors for the developing pouch young

Marsupials have a very different reproductive strategy to eutherians. An Australian marsupial, the tammar wallaby (Macropus eugenii) has a very short pregnancy of about 26.5 days, with a comparatively long lactation of 300-350 days. The tammar mother gives birth to an altricial, approximately 400 mg young that spends the first 200 days postpartum (p.p.) in its mother's pouch, permanently (0-100 days p.p.; Phase 2A) and then intermittently (100-200 days p.p.; Phase 2B) attached to the teat. The beginning of Phase 3 marks the first exit from the pouch (akin to the birth of a precocious eutherian neonate) and the supplementation of milk with herbage. The marsupial mother progressively alters milk composition (proteins, fats and carbohydrates) and individual milk constituents throughout the lactation cycle to provide nutrients and immunological factors that are appropriate for the considerable physiological development and growth of her pouch young. This review explores the changes in tammar milk components that occur during the lactation cycle in conjunction with the development of the young.

Rapid changes in Atlantic grey seal milk from birth to weaning - immune factors and indicators of metabolic strain

True seals have the shortest lactation periods of any group of placental mammal. Most are capital breeders that undergo short, intense lactations, during which they fast while transferring substantial proportions of their body reserves to their pups, which they then abruptly wean. Milk was collected from Atlantic grey seals (Halichoerus grypus) periodically from birth until near weaning. Milk protein profiles matured within 24 hours or less, indicating the most rapid transition from colostrum to mature phase lactation yet observed. There was an unexpected persistence of immunoglobulin G almost until weaning, potentially indicating prolonged trans-intestinal transfer of IgG. Among components of innate immune protection were found fucosyllactose and siallylactose that are thought to impede colonisation by pathogens and encourage an appropriate milk-digestive and protective gut microbiome. These oligosaccharides decreased from early lactation to almost undetectable levels by weaning. Taurine levels were initially high, then fell, possibly indicative of taurine dependency in seals, and progressive depletion of maternal reserves. Metabolites that signal changes in the mother’s metabolism of fats, such as nicotinamide and derivatives, rose from virtual absence, and acetylcarnitines fell. It is therefore possible that indicators of maternal metabolic strain exist that signal the imminence of weaning.

Mammary cell-activating factor regulates the hormone-independent transcription of the early lactation protein (ELP) gene in a marsupial

The regulation of the tammar wallaby (Macropus eugenii) early lactation protein (ELP) gene is complex. ELP is responsive to the lactogenic hormones; insulin (I), hydrocortisone (HC) and prolactin (PRL) in mammary gland explants but could not be induced with lactogenic hormones in tammar primary mammary gland cells, nor in KIM-2 conditionally immortalised murine mammary epithelial cells. Similarly, ELP promoter constructs transiently-transfected into human embryonic kidney (HEK293T) cells constitutively expressing the prolactin receptor (PRLR) and Signal Transducer and Activator of Transcription (STAT)5A were unresponsive to prolactin, unlike the rat and mouse β-casein (CSN2) promoter constructs. Identification of the minimal promoter required for the hormone-independent transcription of tammar ELP in HEK293Ts and comparative analysis of the proximal promoters of marsupial ELP and the orthologous eutherian colostrum trypsin inhibitor (CTI) gene suggests that mammary cell-activating factor (MAF), an E26 transformation-specific (ETS) factor, may bind to an AGGAAG motif and activate tammar ELP.