Doxorubicin Affects Testicular Lipids with Long-Chain (C18-C22) and Very Long-Chain (C24-C32) Polyunsaturated Fatty Acids

Doxorubicin disrupts spermatogenesis by causing apoptosis of spermatogonia and primary spermatocytes. The aim of this study was to examine the effect of this agent on adult rat testicular lipids and their fatty acids. A single dose (7.5 mg/kg) and a multidose regime (3 mg/kg once a week for 4 weeks) were evaluated. Both treatments resulted in the gradual loss of spermatogenic cells and determined a marked reduction in testicular size and weight 9 weeks after their start. Germ cell loss was accompanied by a decrease in phospholipids, including glycerophospholipids and sphingomyelin. Concomitantly, glycerophospholipids lost selectively their major polyunsaturated fatty acid (PUFA), 22:5n-6, and sphingomyelin lost its major very long-chain PUFA (VLCPUFA), 28:4n-6 and 30:5n-6. The molecular species from which the lost polyenes originated were thus a trait of germ cells. A transient peak of 16:0-ceramide was observed 48 h after the single dose. In both doxorubicin regimes, sphingomyelin and ceramide with reduced amounts of VLCPUFA after about 4 weeks and with no VLCPUFA after 9 weeks resulted. By contrast, triglycerides and especially cholesterol esters (CE) tended to accumulate in the testes undergoing germ cell death, probably in the surviving Sertoli cells, their fatty acid patterns suggesting that initially, these lipids retained part of the PUFA coming from, or no longer used for, the synthesis of germ cell glycerophospholipids. As the latter decreased, CE accumulated massively 9 weeks after starting doxorubicin treatment, 20:4n-6 becoming their major PUFA. Part of these CEs may derive from surviving steroidogenic cells.Fil: Zanetti, Samanta Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Maldonado, Eduardo N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Aveldaño, Marta Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

Long-term biopermanence of ceramides, cholesteryl esters, and ether-linked triglycerides with very-long-chain PUFA in the cadmium-damaged testis

Cadmium is known to harm rat testis by causing the dose-dependent apoptotic or necrotic death of seminiferous epithelium cells. Here we investigated how this affects the lipids with long-chain (C18-C22) and very-long-chain (C24-C32) polyunsaturated fatty acids (VLCPUFA) typical of spermatogenic and Sertoli cells. A severe acute inflammatory reaction resulted from the massive necrotic death of these cells two days after a single high (4 mg/kg) dose of CdCl2. This led to the conversion of most testicular glycerophospholipids to diradylglycerols (DRG) and free fatty acids (FFA) and of most sphingomyelins to ceramides (Cer). By day 30 the testis weight had decreased three fold. The DRG and FFA had been metabolized but, unexpectedly, ceramides persisted. Also slow to disappear were VLCPUFA-containing triacylglycerols from former germ cells and ether-linked triglycerides and cholesteryl esters (CE) from former Sertoli cells. Similar results were observed 30 and 45 days after administering repeated small non proinflammatory CdCl2doses (1 mg/kg). At day 30 after both treatments, an amorphous material replaced the original seminiferous tubules and testicular macrophages populated the interstitium. Species of CE and etherlinked triglycerides containing fatty acids other than VLCPUFA steadily accumulated in the irreversibly damaged testis, a manifestation of the activity of phagocytic cells. The long-term permanence of original VLCPUFA-containing neutral lipids, especially ceramides, indicates that these cells were slow to clear out the acellular material contained in seminiferous tubules, pointing to a form of silent chronic inflammation as an additional outcome of the multifactorial commotion caused in the testis by experimentally administered cadmium.Fil: Zanetti, Samanta Romina. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET Bahía Blanca. Instituto de Investigaciones Bioquímicas Bahía Blanca (i); ArgentinaFil: Aveldaño, Marta I.. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico CONICET Bahía Blanca. Instituto de Investigaciones Bioquímicas Bahía Blanca (i); Argentin

Diferencias en la fisuración por corrosión de las armaduras comprimidas o traccionadas en vigas de hormigón

En este trabajo, se presentan los resultados de investigaciones realizadas en vigas de hormigón armado, cuyas armaduras estaban en proceso corrosivo y se encontraban comprimidas o traccionadas, con distintos valores de tensión. Se efectuó el seguimiento de la fisuración, originada por la corrosión de las armaduras, a fin de determinar si existía un comportamiento diferente en elementos sometidos a tracción o a compresión. Se realizó la gravimetría de las barras corroídas, para determinar la pérdida de peso generada por la corrosión, en ambos casos. Paralelamente, en probetas de hormigón, realizadas con la misma dosificación, sometidas a esfuerzo de compresión, se realizaron ensayos de Capacidad de Succión Capilar, para determinar la influencia de la compresión, en la posibilidad del desplazamiento de fluidos dentro del hormigón. En edificios de hormigón del patrimonio moderno, las conclusiones obtenidas de estos ensayos, permiten detectar la necesidad de intervención y reparación de los elementos afectados por corrosión, con mayor o menor celeridad, de acuerdo a la magnitud y forma de la fisuración, según que el elemento esté comprimido o traccionado.Tópico 6: Patrimonio Moderno, incluye obras de ingeniería. Construcciones en Hormigón Armado. Problemáticas de durabilidad y corrosión de armaduras

Lipids and spermatogenesis : very long story

Our story of lipids containing PUFA with very long chains (VLCPUFA) started three decades ago with the finding, in the membranes of retinal rod outer segments, of phosphatidylcholine species that contained 22:6n-3 at sn-2 and a series of fatty acids that were elongated versions (up to C36) of common C20 and C22 PUFA (20:4n-6, 20:5n-3, 22:5n-6, and 22:6n-3) at sn-1 . Other authors found similar VLCPUFA, amide-bound to sphingosne in sphingomyelin (SM), in mammalian testis and spermatozoa.Fil: Aveldaño , Marta. Consejo Nacional de Investigaciones Científicas y Técnica

Differentiation-linked changes in the biosynthesis and turnover of sphingomyelins in rat male germ cells: genes involved and effects of testosterone

In rodents, sphingomyelins (SMs) species with very-long-chain polyunsaturated fatty acid (VLCPUFA) are required for normal spermatogenesis. Data on the expression of enzymes with roles in their biosynthesis and turnover during germ cell differentiation and on possible effects on such expression of testosterone (Tes), known to promote this biological process, were lacking. Here we quantified, in isolated pachytene spermatocytes (PtS), round spermatids (RS), and later spermatids (LS), the mRNA levels from genes encoding ceramide (Cer), glucosylceramide (GlcCer), and SM synthases (Cers3, Gcs, Sms1, and Sms2) and sphingomyelinases (aSmase, nSmase) and assessed products of their activity in cells in culture using nitrobenzoxadiazole (NBD)-labeled substrates and [3H]palmitate as precursor. Transcript levels from Cers3 and Gcs were maximal in PtS. While mRNA levels from Sms1 increased with differentiation in the direction PtS→RS→LS, those from Sms2 increased between PtS and RS but decreased in LS. In turn, the nSmase transcript increased in the PtS→RS→LS order. During incubations with NBD-Cer, spermatocytes produced more GlcCer and SM than did spermatids. In total germ cells cultured for up to 25 h with NBD-SM, not only abundant NBD-Cer but also NBD-GlcCer were formed, demonstrating SM→Cer turnover and Cer recycling. After 20 h with [3H]palmitate, PtS produced [3H]SM and RS formed [3H]SM and [3H]Cer, all containing VLCPUFA, and Tes increased their labeling. In total germ cells, Tes augmented in 5 h the expression of genes with roles in VLCPUFA synthesis, decreased the mRNA from Sms2, and increased that from nSmase. Thus, Tes enhanced or accelerated the metabolic changes occurring to VLCPUFA-SM during germ cell differentiation.Fil: Santiago Valtierra, Florencia Ximena. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Aveldaño, Marta Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Oresti, Gerardo Martin. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin

Enzymes involved in the biosynthesis of sphingolipids with very-long-chain PUFA concur with male germ cell differentiation

The sphingolipids sphingomyelin (SM) and ceramide (Cer), of male rodent germ cells (spermatocytes, spermatids) and spermatozoa contain very-long-chain (C28-C32) polyenoic fatty acids (VLCPUFA) in nonhydroxy (n-V) and 2-hydroxy forms (h-V) not present in Sertoli cells. During postnatal development, SM and Cer species with n-V appear in testes concomitantly with pachytene spermatocytes and those with h-V with spermatids. Both are able to biosynthesize their own sphingolipids, the former more actively than the latter. The biosynthesis of n-V requires elongation of PUFA (20:4n-6, 22:5n-6) by elongation of very-long-chain fatty acid (Elovl) proteins, while that of h-V requires a fatty acid 2-hydroxylase (Fa2h). Elovl5 and Elovl2, coding for enzymes responsible for PUFA biosynthesis, and Elovl4, in turn responsible for the formation of PUFA longer than C26, are actively expressed in germ cells. The Elovl4 protein is exclusively expressed in germ cells in a stage-dependent manner, spermatocytes displaying the highest Elovl4 protein levels and enzymatic activity. Along with high proportion of h-V Cer and h-V SM species, the Fa2h protein is mainly concentrated in late spermatids, in the step of spermiogenesis in which they elongate and their heads change shape. Consistently, spermatocytes express the highest levels of ceramide synthase 3, required for the N-acylation of sphingosine with a VLCPUFA, while spermatids express the highest levels of SM synthase 2. Irrespective of the maturation stage, the small raftlike domains of the germ cell plasma membrane contain species of SM and Cer with saturated fatty acids, while those containing n-V and h-V abound in the large non-raft areas. These species, with unique physico-chemical properties, could play a structural role facilitating the germ cell shape changes associated with the progress of spermatogenesis. If released from such species, free n-V and h-V could be involved in germ cell differentiation as potential precursors of uncommon elovanoid-like bioactive derivatives.Fil: Oresti, Gerardo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Santiago Valtierra, Florencia Ximena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Reyes, Juan. Pontificia Universidad Católica de Valparaíso; ChileFil: Aveldaño, Marta Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaCongreso Latinoamericano Conjunto de ReproducciónSantiagoChileSociedad Chilena de Reproducción y Desarroll

Unique thermal behavior of sphingomyelin species with nonhydroxy and 2-hydroxy very-long-chain (C28-C32) PUFAs

In rat germ cells and spermatozoa, sphingomyelin (SM) contains molecular species with nonhydroxy (n) and 2-hydroxy (h) very-long-chain polyunsaturated fatty acids (V), the most abundant being SMs with (n- and h-) 28:4n-6, 30:5n-6, and 32:5n-6 as acyl chains. The aim of this study was to gain information about their thermotropic behavior and interactions with other lipids. After isolation from rat testis, multilamellar and giant unilamellar vesicles from these SMs were examined using fluorescent probes. Only n-32:5 SM and h-32:5 SM displayed a gel-liquid transition temperature (Tt ≈ 21?22°C), the rest remaining in the liquid state in the 5°C?45°C range. The degree of order was larger in bilayers of any of the h-V SMs than in those of their chain-matched n-V SMs. Both, but n-V SM relatively more than h-V SM, decreased the Tt of dimyristoylphosphatidylcholine as their proportion increased in binary phosphatidylcholine:SM liposomes. In contrast to the established ability of 16:0 SM to form lateral cholesterol/SM-rich ordered domains in ternary dioleoylphosphatidylcholine:cholesterol:SM bilayers, neither n-V SM nor h-V SM showed a tendency to do so. Thus, these SMs are in the fluid state and are not involved in this type of domains in spermatozoa at physiological temperatures. However, this state could be altered at the very low temperatures at which these gametes are usually preserved.Fil: Peñalva, Daniel Alejandro. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Furland, Natalia Edith. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Lopez, Gustavo H.. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; ArgentinaFil: Aveldaño, Marta Isabel. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Antollini, Silvia Susana. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); Argentin

Atypical surface behavior of ceramides with nonhydroxy and 2-hydroxy very long-chain (C28-C32) PUFAs

Unique species of ceramide (Cer) with very-long-chain polyunsaturated fatty acid (VLCPUFA), mainly 28?32 carbon atoms, 4?5 double bonds, in nonhydroxy and 2-hydroxy forms (n-V Cer and h-V Cer, respectively), are generated in rat spermatozoa from the corresponding sphingomyelins during the acrosomal reaction. The aim of this study was to determine the properties of these sperm-distinctive ceramides in Langmuir monolayers. Individual Cer species were isolated by HPLC and subjected to analysis of surface pressure, surface potential, and Brewster angle microscopy (BAM) as a function of molecular packing. In comparison with known species of Cer, n-V Cer and h-V Cer species showed much larger mean molecular areas and increased molecular dipole moments in liquid expanded phases, which suggest bending and partial hydration of the double bonded portion of the VLCPUFA. The presence of the 2-hydoxyl group induced a closer molecular packing in h-V Cer than in their chain-matched n-V Cer. In addition, all these Cer species showed liquid-expanded to liquid-condensed transitions at room temperature. Existence of domain segregation was confirmed by BAM. Additionally, thermodynamic analysis suggests a phase transition close to the physiological temperature for VLCPUFA-Cers if organized as bulk dispersions.Fil: Peñalva, Daniel Alejandro. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Oresti, Gerardo Martin. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Dupuy, Fernando Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Antollini, Silvia Susana. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Maggio, Bruno. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Aveldaño, Marta Isabel. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Fanani, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); Argentin

Incorporación de aditivos en hormigones reciclados para modificar sus propiedades

Para realizar construcciones más sustentables, se utilizan hormigones donde un porcentaje del agregado grueso se reemplaza por hormigón triturado proveniente de la demolición de estructuras cuya vida útil ha finalizado. Por ello, la evaluación de las propiedades de estos hormigones resulta importante. En este trabajo, se estudiaron propiedades mecánicas (resistencia a compresión y tracción indirecta) y físicas relacionadas con la estructura de poros (absorción capilar) de hormigones elaborados con agregado grueso reciclado. Para ello, se moldearon probetas de hormigón con distinta relación agua/cemento y diferentes aditivos: Incorporador de Aire, Superfluidificante e Incorporador de Aire junto con Superfluidificante. Se analizaron las propiedades antes mencionadas para determinar las posibilidades y limitaciones de aplicación de las distintas mezclas ensayadas