Nomenclature of the Proteins of Cows’ Milk—Sixth Revision

Regulated exocytosis of secretory granules or dense-core granules has been examined in many well-characterized cell types including neurons, neuroendocrine, endocrine, exocrine, and hemopoietic cells and also in other less well-studied cell types. Secretory granule exocytosis occurs through mechanisms with many aspects in common with synaptic vesicle exocytosis and most likely uses the same basic protein components. Despite the widespread expression and conservation of a core exocytotic machinery, many variations occur in the control of secretory granule exocytosis that are related to the specialized physiological role of particular cell types. In this review we describe the wide range of cell types in which regulated secretory granule exocytosis occurs and assess the evidence for the expression of the conserved fusion machinery in these cells. The signals that trigger and regulate exocytosis are reviewed. Aspects of the control of exocytosis that are specific for secretory granules compared with synaptic vesicles or for particular cell types are described and compared to define the range of accessory control mechanisms that exert their effects on the core exocytotic machinery.

Secretory Granule Exocytosis

Nomenclature of Proteins of Cow's Milk: Fifth Revision

Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal calf health Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunoglobulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption The practice of colostrum pooling, the breed and presence of the dam, and the presence of respiratory acidosis in the calf also may affect passive transfer Various tests have been reported to accurately measure passive transfer status in neonatal calves The radial immunodiffusion and the enzyme-linked immunosorbent assay (ELISA) are the only tests that directly measure serum IgG concentration All other available tests including serum total solids by refractometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum gamma-glutamyl transferase activity, and whole blood glutaraldehyde gelation estimate serum IgG concentration based on concentration of total globulins or other proteins whose passive transfer is statistically associated with that of IgG This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transfer status, testing modalities, effects of failure of passive transfer on baseline mortality, consequences of failure of passive transfer, and some treatment options Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1939-1676.2000.tb02278.x

Passive transfer of colostral immunoglobulins in calves.

Dissociated normal mammary epithelial cells from prelactating mice were plated on different substrates in various medium-serum-hormone combinations to find conditions that would permit maintenance of morphological differentiation. Cells cultured on floating collagen membranes in medium containing insulin, hydrocortisone and prolactin maintain differentiation through 1 month in culture. The surface cells form a continuous epithelial pavement. Some epithelial cells below the surface layer rearrange themselves to form alveolus-like structures. Cells at both sites display surface polarization; microvilli and tight junctions are present at their medium-facing or luminal surface and a basal lamina separates the epithelial components from the gel and stromal cells. Occasinal myoepithelial cells, characterized by myofilaments and plasmalemmal vesicles, are identified at the basal surface of the secretory epithelium. In contrast, cells cultured on plastic, glass or collagen gels attached to Petri dishes form a confluent epithelial sheet showing surface polarization, but lose secretory and myoepithelial specializations. If these dedifferentiated cells are subsequently maintained on floating collagen membranes, they redifferentiate. There is little DNA synthesis in cells on collagen gels, in contrast to Petri-dish controls. Protein synthesis in cells on floating collagen membranes increases over T0 values and remains constant through 7 days in culture whereas it decreases on attached gels; however, if the gels are freed to float, protein synthesis increases sharply and parallels that seen on floating membranes.

Bruce L. Larson

Papers

Immunoglobulin production and transport by the mammary gland.

Heat Denaturation of the Specific Serum Proteins in Milk

Amperometric Method for Determining Sorption of Iodine by Starch

Age and previous lactations as factors in the amount of bovine colostral immunoglobulins.

Production and turnover of IgG1 and IgG2 immunoglobulins in the bovine around parturition.