Abstract:

Linoleic acid (LA) is a polyunsaturated fatty acid present in high concentrations in bovine follicular fluid; when added to maturation culture media, it affects oocyte competence (depending on the type and concentration of LA used). To date, little is known about the effective level of incorporation of LA and there is apparently no information regarding its esterification into various lipid fractions of the oocyte and its effect on neutral lipid storage. Therefore, the objective was to assess the uptake and subcellular lipid distribution of LA by analyzing incorporation of radiolabeled LA into oocyte polar and neutral lipid classes. The effects of various concentrations of LA on the nuclear status and cytoplasmic lipid content of bovine oocytes matured in vitro was also analyzed, with particular emphasis on intermediate concentrations of LA. Neutral lipids stored in lipid droplets were quantified with a fluorescence approach. Linoleic acid at 9 and 43 μM did not affect the nuclear status of oocytes matured in vitro, and 100 μM LA inhibited germinal vesicle breakdown, resulting in a higher percentage of oocytes arrested at the germinal state (43.5 vs. 3.0 in controls; P < 0.05). Bovine oocytes actively incorporated LA from the maturation medium (83.4 pmol LA per 100 oocytes at 22 hours of incubation; P < 0.05) and metabolized it mainly into major lipid classes, e.g., triacylglycerols and phospholipids (61.1% and 29.3%, respectively). Supplementation of the maturation medium with LA increased triacylglycerol accumulation in cytoplasmic lipid droplets at all concentrations assayed (P < 0.05). In conclusion, LA added to a defined maturation medium at concentrations that did not alter the nuclear status of bovine oocytes matured in vitro (9 and 43 μM) improved their quality by increasing the content of neutral lipids stored in lipid droplets. By directing the free fatty acid (LA) to triacylglycerol synthesis pathways and increasing the degree of unsaturation of membrane phospholipids, the oocyte was protected from lipotoxic effects (with an expectation of improved cryotolerance).

EEA Balcarce

Author affiliation: Carro, María De Las Mercedes. INTA. Estación Experimental Agropecuaria Balcarce. Departamento de Producción Animal. Biotecnología de la Reproducción; Argentina

Author affiliation: Buschiazzo, Jorgelina. INTA. Estación Experimental Agropecuaria Balcarce. Departamento de Producción Animal. Biotecnología de la Reproducción; Argentina. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca; Argentina

Author affiliation: Rios, Glenda Laura. INTA. Estación Experimental Agropecuaria Balcarce. Departamento de Producción Animal. Biotecnología de la Reproducción; Argentina

Author affiliation: Oresti, Gerardo Martin. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca; Argentina

Author affiliation: Alberio, Ricardo. INTA. Estación Experimental Agropecuaria Balcarce. Departamento de Producción Animal. Biotecnología de la Reproducción; Argentina

Abstract:

From seven of the eight studied coalified ovules (Trigonocarpus grandis: Sydney Coalfield, Canada) sufficient material could be macerated (Schulze's process) for histochemical investigation. This encompasses histological identification of the ovular structure/tissue components by methods of Nomarski phase-contrast microscopy, and determination of the chemical make-up by Fourier transform infrared (FTIR) spectroscopy. The generated data are then input for principal component analysis (PCA), based on the chemometric approach. Not included in PCA, but complementary to it, are data from pyrolysis gas chromatography/mass spectrometry (Py-GC/MS), powder X-ray diffraction, carbon 13 magnetic resonance analyses (13CNMR), and introducing mass spectrometric data of selected epidermal/nucellar and vitrain samples. Addressed amongst other questions are evolution of ovular chemical grouping which includes vitrain and cutin; if coalified ovules reflect optimally original Carboniferous seeds, and why; and can chemotaxonomy/systematics of medullosalean ovules be advanced through histochemistry? Demonstrably preserved in T. grandis are outer and inner integumentary epidermises, a double-walled nucellus with nucellar cuticles, and endospermous tissue. These structures are protected by tecta or nucellar cuticles. Molecular structures for epidermises and nucellii are probably not the same which is suggested by initial mass-spectrometric experiments. These “hard” parts are most resistant to diagenetic influences, correlating with aliphatic (lipid) composition, but facies changes influenced fossilization as in ovular molds/casts vitrain lost all its otherwise preserved tissues. This collectively suggests a narrow window of fossilizing conditions by coalification. Inferred from PCA are transitional changes, rather than sharp delineation, where the nucellus occupies a chemical composition intermediate between epidermis/cutin and the vitrain. Integumentary fibers, tectum, inorganic replacement of an epidermis, and some nucellar specimens are difficult to group by PCA. Nucellar material is probably suited for chemotaxonomic/systematic research because of the lipid chemistry.

Author affiliation: Zodrow, Erwin L.. Cape Breton University. Carboniferous Palaeobiology Laboratory; Canadá

Author affiliation: D`angelo, José Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Cape Breton University. Carboniferous Palaeobiology Laboratory; Canadá

Author affiliation: Al-Shraah, Ahmad. Memorial University Of Newfoundland. Department of Chemistry; Canadá

Abstract:

The nucellar beak is a proboscis-like outgrowth of the nucellus at the micropylar end, being the obliged path for the pollen tube entering the ovule. Among the few angiosperm families with nucellar beak, Cucurbitaceae is remarkable because the pollen tube may develop at least two types of growth within the nucelar beak: tubular, and ampulliform. Wondering about the possibility that Cucurbitaceae ovules may express some histological variation that could be related to pollen tube growth within the nucellar beak, we performed a compared anatomical, histochemical study of the nucellar beak and pollen tube growth of ten species of Cucurbitaceae. Results show that Cucurbitaceae ovules are diverse in size and proportions (of integuments, nucellar body, and nucellar beak), and they have at least four types of nucellar beak histology: pectic-tracked, secretory-like, amylaceous, and mixed. Amylaceous and mixed nucellar beaks are related to the ampulliform growth of the pollen tube, which could have appeared independently in most derived tribes of Cucurbitaceae, although information about nucellar beak structure in the basal tribes is still needed. In addition, the understanding of the relation between amylaceous nucellar beaks and the ampulliform growth of the pollen tube, whose function is still to be discovered, might open the possibility of a unique model of pollen tube - ovule co-evolution in angiosperms.

Author affiliation: Lizarazu, Mabel Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Author affiliation: Pozner, Raúl Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Abstract:

Nymphaeaceae occupies an important phylogenetic position because of their placement as one of the basal angiosperms. From this perspective, morphological studies in the family are of great value to understanding plant phylogeny and evolution. Ovule development and female gametophyte in Nymphaea amazonum, N. gardneriana (subgenus Hydrocallis) and in Victoria cruziana were analyzed in order to provide further progress in characters of potential evolutionary interest. The ovules of all species are anatropous, bitegmic, distomic, weakly crasinucellate, and present an epistase. The female gametophyte is four-celled and corresponds to the Schisandra type, distinctive of the Nymphaeales. Comparisons among ovules of the subgenera of Nymphaea and others allied genera show differences with respect to micropyle conformation, thickness of nucellus and outer integument, and its degree of development on the raphal side. The studied species of Nymphaea share an annular outer integument and linear triad of megaspores. These results fill gaps in the current incomplete knowledge of character states especially within Nymphaea. In subgenus Hydrocallis, the ovules have an outer integument not markedly cup-shaped in contrast to subgenus Nymphaea, since the micropyle is closer to the funiculus as in Nuphar. The present observations suggest that the ovule morphology has diversified in Nymphaea and the characters studied clearly show no evidences to support the hypothesis of a monophyletic genus.

Author affiliation: Zini, Lucia Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

Author affiliation: Galati, Beatriz Gloria. Universidad de Buenos Aires. Facultad de Agronomia; Argentina

Author affiliation: Ferrucci, Maria Silvia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina

Abstract:

La síntesis del óxido nítrico (NO) ha sido descripta en diferentes órganos de mamíferos. Esta molécula ha sido involucrada en procesos fisiológicos tales como la relajación de la musculatura lisa, inhibición de plaquetas, neurotransmisión y regulación del sistema inmune. En el sistema reproductor de la hembra el NO está involucrado en la ovulación, fertilización, luteólisis y mantenimiento de la preñez. Sin embargo, hasta ahora no ha sido descripto la participación de esta molécula en el transporte de los ovocitos/embriones hacia la cavidad uterina. Trabajos previos realizados en nuestro laboratorio habían demostrado la participación del NO en la relajación de la musculatura lisa en útero de ratas estrogenizadas. En este trabajo hemos demostrado, mediante diferentes estrategias metodológicas, ya sea enzimáticas o inmunológicas, la presencia de tres isoformas de NO sintasa en el oviducto de la rata, las cuales parecen estar reguladas fisológicamente, en ciclo y preñez temprana. La evaluación del transporte ovular y transferencia de microesferas de dextrano al oviducto en presencia de diferentes inhibidores de la NO sintasa, revelaron que el NO participa en los mecanismos moleculares que controlan el proceso de transporte atenuando la actividad de dos efectores mecánicos: la musculatura lisa del órgano y el batido ciliar de las células epiteliales. En conjunto, los resultados obtenidos en el presente trabajo, sugieren que el óxido nítrico podría actuar como una señal paracrina o autocrina entre las diferentes capas de la pared oviductal, promoviendo un sistema de regulación inhibítoria y de esta manera contribuir al mantenimiento de la quiescencia oviductal en el transcurso del pasaje de los huevos hacia la cavidad uterina. En la regulación de este proceso estarían involucradas moléculas contráctiles tales como PGF2α u ocitocina y las hormonas ováricas.

The synthesis of nitric oxide (NO) has been found in different mammalian organs. NO actions have been previously described in the vascular, the nervous and the immune systems. In the female reproductive organs, it was found that NO is involved in ovulation, fertilization, luteolysis and pregnancy. Nevertheless, the role of nitric oxide in ovum transport in mammals has not been studied. In the present work we demonstrated the prescence of three isoforms of NO synthase in rat oviducts, using differents methodologies. These isoenzimes showed a differential synthesis rate in oestral cycle or in pregnancy. The assessment of ova transport and dextran blue microspheres transfer inside the oviduct, after NO synthase inhibitors administration, revealed that the endogenous NO is involved in the molecular mechanisms that regulate the ovum passage towards the uterus, by decreasing the oviductal smooth muscle contractions and the epithelial ciliar beat. Our results provide new evidence that nitric oxide could act as a paracrine or autocrine signal between different layers of the oviductal wall, providing a regulatory system that inhibits ovum transport allowing the oviductal quiescence. The control of these signal pathways could involve molecules such as PGF2α or oxytocin and ovarian hormones.

Author affiliation: Perez Martinez, Silvina L.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.

Abstract:

Pollen limitation occurs frequently in plant populations and, as result, many ovules are wasted. One possible adaptive explanation posits that ovule overproduction represents a 'bet-hedging' strategy against pollination inefficiency. This hypothesis is supported by comparative evidence showing that unpredictability in pollen receipt is positively associated with an increasing number of ovules per flower across species. Yet, this proposition has not been tested at the intraspecific level, where natural selection operates. Here, we evaluated the relationship between pollination unpredictability, considering both pollination quantity and quality, and number of ovules per flower, across 16 populations of the south-Andean generalist treelet Embothrium coccineum J.R.Forster and G.Forst from north-western Patagonia, which occurs along a west-east gradient of decreasing rainfall. Despite sizable variation in mean number of ovules per flower, we found no increase in ovule production with increasing pollination unpredictability across populations. Instead, we found that mean number of ovules per flower decreased with decreasing rainfall. Therefore, in this species, there was no support for the proposal that ovule overproduction represents a bet-hedging strategy against unpredictable pollen receipt. Rather, the number of ovules per flower seems to be conditioned primarily by resource availability.

Author affiliation: Chalcoff, Vanina Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Author affiliation: Aizen, Marcelo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina

Abstract:

Five coalified ovules of the type Trigonocarpus grandis are investigated four of which co-occur with tree-fern foliage Alethopteris pseudograndinioides in the medullosalean forest (basal Cantabrian), and the fifth occurs in top Asturian D (Sydney Coalfield, Canada). Addressed are questions of variability (what is a coalified ovule?), comparison with petrified ovules, pyrolysates and the original make-up of the grandis seeds, and can similar chemistry proxy for organic connection between ovule and foliage? The results demonstrate variable preservation quality despite similar thermal-maturity levels in the geological interval in which the ovules were collected. Nevertheless, the proposed T. grandis model is based on evidence from epidermises associated with inner and outer integuments, and a two-layered nucellus with granulose exine that is covered by a diaphanous layer (tectum?) and nucellar cuticle. The latter separates the inner cuticle of the inner integumentary surface from the megaspore membrane. Parenchymatous and sclerenchymatous cell structures are rare, whereas evidence for integuments, vasculature, and sclerotesta is equivocal. Overall, these features compare with petrified seeds. 13C nuclear-magnetic resonance analysis suggests that the A. pseudograndinioides tree fern bore T. grandis seeds. Pyrolysates from low and high molecular weights can almost exclusively be grouped with alkenes and aromatics; phenolics, furan and branched alkenes; and with n-alkene/n-alkane homologous series (~ 3 to 1) for cuticles from the inner integumentary surface which suggests a cutin-based, aliphatic-rich biomacromolecule. More generally, preservation is presumed correlative with aliphatic content, but not exclusively, and organ–organ linkage by spectrochemical means certainly has potential as a new research vector in palaeobotany.

Author affiliation: Zodrow, Erwin L.. Cape Breton Universit. Palaeobotanical Laboratory; Canadá

Author affiliation: Helleur, Robert. Memorial University of Newfoundland. Department of Chemistry; Canadá

Author affiliation: Werner-Zwanziger, Ulrike. Dalhousie Universit. Department of Chemistry; Canadá

Author affiliation: Chen, Banghao. Dalhousie Universit. Department of Chemistry; Canadá

Author affiliation: D` Angelo, José Alejandro. Cape Breton Universit. Palaeobotanical Laboratory; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina

Abstract:

This is the first report of the ultrastructure of the stigma and style during and after anthesis in Helianthus annuus L. using light and transmission electron microscopy. The stigma is bifid with unicellular papillae. There is no secretion of lipids, carbohydrates or proteins at anthesis. The style is semisolid in the upper portion, closer to the stigma, and becomes solid below. Ultrastructural changes on cells of the stigma and the style are described. The transmitting tissue of the ovule is first evident 40 minutes after pollination and persists during the first stages of embryogenesis. Only one pollen tube per micropyle was observed growing through this tissue.

Author affiliation: Gotelli, Marina María. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Galati, B. G.. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina

Author affiliation: Medan, Diego. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina