Primary cilia disappear in rat podocytes during glomerular development

Most tubular epithelial cell types express primary cilia, and mutations of primary-cilium-associated proteins are well known to cause several kinds of cystic renal disease. However, until now, it has been unclear whether mammalian podocytes express primary cilia in vivo. In this study, we determined whether primary cilia are present in the podocytes of rat immature and mature glomeruli by means of transmission electron microscopy of serial ultrathin sections. In immature glomeruli of fetal rats, podocytes express the primary cilia with high percentages at the S-shaped body (88 ± 5%, n = 3), capillary loop (95 ± 4%, n =  4), and maturing glomerulus (76 ± 13%, n = 5) stages. The percentage of ciliated podocytes was significantly lower at the maturing glomerulus stage than at the former two stages. In mature glomeruli of adult rats, ciliated podocytes were not found at all (0 ± 0%, n = 11). These findings indicate that the primary cilia gradually disappear in rat podocytes during glomerular development. Since glomerular filtration rate increases during development, the primary cilia on the podocytes are subjected to a stronger bending force. Thus, the disappearance of the primary cilia presumably prevents the entry of excessive calcium-ions via the cilium-associated polycystin complexes and the disturbance of intracellular signaling cascades in mature podocytes

Ultrastructural and biochemical analysis of epidermal xanthophores and dermal chromatophores of the teleost Sparus aurata

We have studied the pigmentary system of the teleost Sparus aurata skin by electron microscopy and chromatographic analysis. Under electron microscopy, we found the dermis to contain the three major types of recognized chromatophores: melanophores, xanthophores and iridophores. Melanophores were more abundant in the dorsal region, whereas the iridophores were more abundant in the ventral region. The most important discovery was that of epidermal xanthophores. Epidermal xanthophores were the only chromatophores in the epidermis, something only found in S. azirara and in a teleost species living in the Antartic sea. In contrast, the biochemical analysis did not establish any special characteristics: we found pteridine and flavin pigments located mostly in the pigmented dorsal region. Riboflavin and pterin were two of the most abundant coloured pigment types, but other colourless pigments such as xanthopterin and isoxanthopterin were also detected

Melanization stimulating factors in the integument of the Mugil cephalus and Dicertranchus labrax

The pigment pattern expression resides in the chromatoblasts of the embryonic skin. The differentiation of these chromatoblasts is influenced by specific local factors such a melanization inhibiting factor (MIF) and a melanization-stimulating factor (MSF). We reveal the presence of these factors by means of a series of experiments on the skin of the marine species of fish Dicertranchus labrax and Mugil cephalus, each with different pigment pattern, the former having a light skin and the latter a darker one. Media conditioned by exposure to dorsal andtor ventral skin, stimulates the melanization of Xenopus laevis neural crest cells throughout a 3 day assay period. Similarly conditioned culture media tested on B16-F10 murine malignant melanocytes, revealed a considerable influence in enzymatic activities: dopachrome tautomerase (DCT), tyrosine hydroxylase and dopa oxidase. The use of media in a dose response basis suggests that the conditioned media may contain both melanophore stimulating and inhibiting factors. The results obtained may actually reflect the resultant activity of the two factors present

Evaluation of a vaccine's DNA against Photobacterium damselae subsp.. piscicida. Study of immune response in the Senegal sole (Solea senegalensis kaup)

Photobacterium damselae subsp. piscicida is the aetiological agent of pasteurellosis, a bacterial disease that affects seriously soles grown in captivity provoking significant mortalities. Until moment, long-term effective and oral protective vaccines to prevent pasteurellosis in sole are not commercially available. In this work, the HSP60 gene from P. d. piscicida was used to prepare a DNA vaccine (pPDPHSP60) that was employed to determine the antibacterial immune response elicited by DNA vaccination in sole. Expression of pPDPHSP60 was confirmed both in transfected cells and in vivo using gut of orally vaccinated sole by RT-PCR analysis. Expression profiles of genes involved in the innate immune system were determined in spleen from orally vaccinated sole using an OpenArray real time PCR approach. Results revealed that oral vaccination induced coordinately the expression of genes involved in the response against bacterial infection. This study has been co-funded by project AQUAGENET (SOE2/P1/ E287) program INTERREG IVB SUDOE, and by project RTA2009-00066-00-00 from the Instituto Nacional de Investigaci&oacute;n y Tecnolog&iacute;a Agraria y Alimentaria (INIA, Spain), and FEDER (EU).www.juntadeandalucia.es/agriculturaypesca/ifapa/aquagenetPhotobacterium damselae subsp. piscicida es el agente etiol&oacute;gico de la pasteurelosis, una enfermedad bacteriana que afecta gravemente a los lenguados criados en cautividad produciendo importantes mortalidades. Hasta el momento, no existen vacunas efectivas comercialmente disponibles con una larga protecci&oacute;n y por v&iacute;a oral para prevenir la pasteurelosis. En este trabajo, el gen HSP60 de P. d. piscicida se utiliz&oacute; para construir una vacuna de ADN (pPDPHSP60) y se us&oacute; para determinar la respuesta inmune antibacteriana provocada por la vacunaci&oacute;n en lenguado. La expresi&oacute;n in vitro e in vivo de pPDPHSP60 fue confirmada mediante RT-PCR, tanto en c&eacute;lulas transfectadas como en intestino de los individuos vacunados oralmente. Los perfiles de expresi&oacute;n de los genes implicados en el sistema inmune se determinaron en bazo de los lenguados vacunados oralmente mediante la t&eacute;cnica de OpenArray PCR en tiempo real. Los resultados demostraron que la expresi&oacute;n de los genes implicados en la respuesta contra infecciones bacterianas aumentaba significativamente de forma coordinada. Este estudio ha sido cofinanciado por el proyecto AQUAGENET (SOE2/P1/ E287) programa INTERREG IVB SUDOE, y por el proyecto RTA2009-00066-00-00 para el Instituto Nacional de Investigaci&oacute;n y Tecnolog&iacute;a Agraria y Alimentaria (INIA, Spain), and FEDER (EU). www.juntadeandalucia.es/agriculturaypesca/ifapa/aquagenet</p

Ultrastructure of the tubular nephron of Testudo graeca (Chelonia). A comparison between hibernating and non-hibernating animals

The tubular nephron of hibernating and nonhibernating specimens of Testudo graeca (Chelonia) was studied by means of conventional light and electron microscopy and histochemistry. The tubular nephron was composed of proximal, intermediate, distal and collecting tubules in both hibernating and nonhibernating animals. The cells of the proximal tubule showed long microvilli, cytoplasmic vacuoles, a developed endoplasmic reticulum and abundant mitochondria. Fat droplets were also observed. The intermediate segment was lined by ciliated and nonciliated cells. The lining cells of the distal tubule presented few microvilli, abundant dense mitochondria and clear vesicles of mucous appearance in the terminal portion. Collecting ducts are composed of mucous and non-mucous cells. Mucous cells presented strong reaction to the histochemical techniques detecting sialoand sulpho-mucins. During hibernation, a progressive vacuolar degeneration of the endoplasmic reticulum was observed in al1 the segments of tubular nephron, which may be caused by a massive intake of extracellular water into the cell

Involution of seminiferous tubules in aged hamsters: an ultrastructural, immunohistochemical and quantitative morphological study

In this study, we examined the age-related changes on morphometric parameters and ultrastructure of seminiferous tubules, and on the expression of extracellular matrix proteins in lamina propria of Syrian hamsters. A significant decrease in the percentage of normal tubules and an increase in the percentage of hypospermatogenic and arrested maturation tubules was observed with aging. Aged animals showed a decrease in tubular diameter, tubular lumen, seminiferous epithelium volume and total tubular volume. However, the total length of seminiferous tubules was significantly increased with aging. The most important ultrastructural changes with aging were the thickening of the lamina propria, the presence of diverse abnormalities in the spermiogenesis process, degeneration of germ cells, and vacuolization and flattening of Sertoli cells showing abundant lipofucsin droplets and residual bodies. Laminin immunoreactivity was found along the lamina propria of seminiferous tubules both in young and aged animals. Fibronectin immunoreactivity was found along the lamina propria and blood vessels. Both laminin and fibronectin total volume of immunostaining per testis was increased in aged hamsters. In conclusion, the agerelated changes in seminiferous tubules of hamster include: a decrease in tubular width and an increase in tubular length; widening of the lamina propria caused by a more extensive connective matrix between the peritubular cells and the basal membrane; and a strong disarrangement of the seminiferous epithelium, including germ cell degeneration and important alterations in both spermiogenesis and Sertoli cell structure