Evolution of Pinnipedia lactation strategies: a potential role for α-lactalbumin?

Despite the considerable variation in milk composition found among mammals, a constituent common across all groups is lactose, the main sugar and osmole in most eutherians milk. Exceptions to this are the families Otariidae (fur seals and sea lions) and Odobenidae (walruses), where lactose has not been detected. We investigated the molecular basis for this by cloning α-lactalbumin, the modifier protein of the lactose synthase complex. A mutation was observed which, in addition to preventing lactose production, may enable otariids to maintain lactation despite the extremely long inter-suckling intervals during the mother's time at sea foraging (more than 23 days in some species).

[1]  S. Orrenius,et al.  HAMLET, protein folding, and tumor cell death. , 2007, Biochemical and biophysical research communications.

[2]  N. Lehman,et al.  Pinniped phylogeny and a new hypothesis for their origin and dispersal. , 2006, Molecular phylogenetics and evolution.

[3]  W. Bowen,et al.  Individual variation in milk composition over lactation in harbour seals (Phoca vitulina) and the potential consequences of intermittent attendance , 2005 .

[4]  J. Arnould,et al.  The lactation cycle of the fur seal , 2005, Journal of Dairy Research.

[5]  Meiyu Xu,et al.  IEC-6 Intestinal Cell Death Induced by Bovine Milk α-Lactalbumin , 2005 .

[6]  C. Streuli,et al.  Apoptosis regulation in the mammary gland , 2004, Cellular and Molecular Life Sciences.

[7]  D. Raleigh,et al.  A protein dissection study demonstrates that two specific hydrophobic clusters play a key role in stabilizing the core structure of the molten globule state of human α‐lactalbumin , 2001, Proteins.

[8]  T. Saito,et al.  Chemical characterisation of the oligosaccharides in hooded seal (Cystophora cristata) and Australian fur seal (Arctocephalus pusillus doriferus) milk. , 2001, Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology.

[9]  C. Guinet,et al.  MATERNAL CARE IN THE SUBANTARCTIC FUR SEALS ON AMSTERDAM ISLAND , 2000 .

[10]  A. Pellegrini,et al.  Isolation and identification of three bactericidal domains in the bovine α-lactalbumin molecule , 1999 .

[11]  W. Strauss.  Preparation of Genomic DNA from Mammalian Tissue , 1998, Current protocols in molecular biology.

[12]  I. Boyd,et al.  Temporal patterns of milk production in Antarctic fur seals (Arctocephalus gazella) , 1995 .

[13]  B. Zhivotovsky,et al.  Apoptosis induced by a human milk protein. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[14]  S. Bergström,et al.  Isolation of mRNA and genomic DNA from epithelial cells in human milk and amplification by PCR. , 1994, BioTechniques.

[15]  J. Vilotte,et al.  Creation and phenotypic analysis of alpha-lactalbumin-deficient mice. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[16]  W. Strauss.  Preparation of Genomic DNA from Mammalian Tissue , 1993, Current protocols in immunology.

[17]  N. Kretchmer,et al.  Lactose synthetase in mammary gland of the California sea lion. , 1972, Biochemical and biophysical research communications.

[18]  Meiyu Xu,et al.  IEC-6 intestinal cell death induced by bovine milk alpha-lactalbumin. , 2005, Bioscience, biotechnology, and biochemistry.

[19]  Ryoichi Nakata.  [Alpha lactalbumin]. , 2004, Nihon rinsho. Japanese journal of clinical medicine.

[20]  I. Boyd,et al.  Reproduction in marine mammals , 1999 .

[21]  D. Boness,et al.  The Behavior, Physiology, and Anatomy of Lactation in the Pinnipedia , 1987 .

[22]  F. H. Fay.  Ecology and Biology of the Pacific Walrus, Odobenus Rosmarus Divergens Illiger , 1982 .

[23]  T. Oka,et al.  Purification and characterization of mouse alpha-lactalbumin and preparation of its antibody. , 1980, The Biochemical journal.

[24]  F. Hytten.  The physiology of lactation. , 1976, Journal of human nutrition.