Kidney of Minke Whale (Baleanoptera acutorostrata): Architecture and structure

Sarmento C. A. P., Ferreira A. O., Rodrigues E. A. F., Lesnau G. G., Rici R. E. G., Abreu D. K., Biasi C. & Miglino M. A. 2012. [Kidney of Minke Whale (Baleanoptera acutorostrata): Architecture and structure.] Rins de Baleia Minke (Baleanoptera acutorostrata): arquitetura e estrutura. Pesquisa Veterinaria Brasileira 32(8): 807-811. Departamento de Cirurgia, Setor de Anatomia dos Animais Domesticos e Silvestres, Universidade de Sao Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Sao Paulo, SP 05508-270, Brazil. E-mail: sarmento@usp.br Among marine mammals, whale is one of the most attention-arousing animals, especially concerning its urinary tract. This system follows the pattern of mammals with regard to its constitution, however, it differs in renal morphology and number of lobes, which, in turn, form complete reniculi, agglutinated in hundreds. This structure is supported by fibrous connective tissue, but highly capable of maintaining electrolyte balance. Six pairs of kidneys of Minke whale (Balaenoptera acutorostrata), collected in 1982, in Cabedelo, Paraiba, Brazil, in the last fishing allowed, were dissected. These kidneys were preserved in 10% formaldehyde and they presented a very large histologic layer of collagen surrounding the medullary wall. The urinary collecting duct form papillary glasses, that reach a single collecting center which discharges in the ureter. It was found that the kidney of Minke whale has a lobe characteristic, with, on average, 700 reniculi; each reniculus has anatomical and functional characteristics of a unipyramidal kidney, with an inner layer (medulla), and an outer layer (cortex), and independent irrigation, with formation of individually arcuate arteries, as observed in unipyramidal terrestrial mammals. However, the set gathering all these reniculi constitutes, in the end, a multilobular and polipyramidal kidney, contrary to the morphology of most terrestrial mammals. It was not possible to distinguish the renicular cortex structures of the Minke whale in the level of light microscopy. Through scanning electron microscopy, it was possible to visualize a cortical layer located between two fibrous capsules. This joint, in turn, consists of connective tissue, which, along with a layer of collagen and elastic fibers, separates the cortex from the medulla; the kidney glomeruli were visualized, completely taken by the glomerular vessels and arranged into several layers. One notices that the glomerular cavity is almost a virtual space into which the glomerular filtrate is drained, and it does not present a globular shape. Vascularization is increased in the medullary region. The difference between the kidneys of terrestrial and marine mammals consists in the arrangement of morphological components, favoring the organ's physiology.

Calcium Binding to Leptospira Outer Membrane Antigen LipL32 Is Not Necessary for Its Interaction with Plasma Fibronectin, Collagen Type IV, and Plasminogen

LipL32 is the most abundant outer membrane protein from pathogenic Leptospira and has been shown to bind extracellular matrix (ECM) proteins as well as Ca2+. Recent crystal structures have been obtained for the protein in the apo-and Ca2+-bound forms. In this work, we produced three LipL32 mutants (D163-168A, Q67A, and S247A) and evaluated their ability to interact with Ca2+ and with ECM glycoproteins and human plasminogen. The D163-168A mutant modifies aspartate residues involved in Ca2+ binding, whereas the other two modify residues in a cavity on the other side of the protein structure. Loss of calcium binding in the D163-D168A mutant was confirmed using intrinsic tryptophan fluorescence, circular dichroism, and thermal denaturation whereas the Q67A and S247A mutants presented the same Ca2+ affinity as the wild-type protein. We then evaluated if Ca2+ binding to LipL32 would be crucial for its interaction with collagen type IV and plasma proteins fibronectin and plasminogen. Surprisingly, the wild-type protein and all three mutants, including the D163-168A variant, bound to these ECM proteins with very similar affinities, both in the presence and absence of Ca2+ ions. In conclusion, calcium binding to LipL32 may be important to stabilize the protein, but is not necessary to mediate interaction with host extracellular matrix proteins.

Effect of dental tissue conditioners and matrix metalloproteinase inhibitors on type I collagen microstructure analyzed by Fourier transform infrared spectroscopy

This study aimed to evaluate the chemical interaction of collagen with some substances usually applied in dental treatments to increase the durability of adhesive restorations to dentin. Initially, the similarity between human dentin collagen and type I collagen obtained from commercial bovine membranes of Achilles deep tendon was compared by the Attenuated Total Reflectance technique of Fourier Transform Infrared (ATR-FTIR) spectroscopy. Finally, the effects of application of 35% phosphoric acid, 0.1M ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine, and 6.5% proanthocyanidin solution on microstructure of collagen and in the integrity of its triple helix were also evaluated by ATR-FTIR. It was observed that the commercial type I collagen can be used as an efficient substitute for demineralized human dentin in studies that use spectroscopy analysis. The 35% phosphoric acid significantly altered the organic content of amides, proline and hydroxyproline of type I collagen. The surface treatment with 0.1M EDTA, 2% chlorhexidine, or 6.5% proanthocyanidin did not promote deleterious structural changes to the collagen triple helix. The application of 6.5% proanthocyanidin on collagen promoted hydrogen bond formation. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.