Long-term effects of chronic light pollution on seasonal functions of European blackbirds (turdus merula)

Light pollution is known to affect important biological functions of wild animals, including daily and annual cycles. However, knowledge about long-term effects of chronic exposure to artificial light at night is still very limited. Here we present data on reproductive physiology, molt and locomotor activity during two-year cycles of European blackbirds (Turdus merula) exposed to either dark nights or 0.3 lux at night. As expected, control birds kept under dark nights exhibited two regular testicular and testosterone cycles during the two-year experiment. Control urban birds developed testes faster than their control rural conspecifics. Conversely, while in the first year blackbirds exposed to light at night showed a normal but earlier gonadal cycle compared to control birds, during the second year the reproductive system did not develop at all: both testicular size and testosterone concentration were at baseline levels in all birds. In addition, molt sequence in light-treated birds was more irregular than in control birds in both years. Analysis of locomotor activity showed that birds were still synchronized to the underlying light-dark cycle. We suggest that the lack of reproductive activity and irregular molt progression were possibly the results of i) birds being stuck in a photorefractory state and/or ii) chronic stress. Our data show that chronic low intensities of light at night can dramatically affect the reproductive system. Future studies are needed in order to investigate if and how urban animals avoid such negative impact and to elucidate the physiological mechanisms behind these profound long-term effects of artificial light at night. Finally we call for collaboration between scientists and policy makers to limit the impact of light pollution on animals and ecosystems

Semejanzas y diferencias entre los códices de Huichapan y de Jilotepec. Dimensión Antropológica Vols. 9-10 Año 4 (1997) enero-agosto

Alvarado Guinchard, Manuel, El Códice de Huichapan. Relato otomí del México prehispánico y colonial, México, INAH (Científica, 48), 1976.Caso, Alfonso, "Comentario de 1928, 1955 y 1967", en Códice Huichapan, México, Telecomunicaciones, 1992.Mendieta, fray Gerónimo de, Historia eclesiástica indiana, Salvador Chávez Hayde (ed.), México, 1945.Reyes Retana, Óscar, Códice de Jilotepec, México, Ayuntamiento de Jilotepec, 1990.____________, El Códice de Huichapan, México, Telecomunicaciones, 1992.Sahagún, fray Bernardino de, Historia general de las cosas de la Nueva España, México, Porrúa, 1977.Torquemada, fray Juan de, Monarquía indiana, México, UNAM, 1975.Sostener que los códices de Jilotepec y de Huichapan son los documentos escritos más antiguos de la cultura otomí no tiene más sustento que los propios códices y la carencia o desconocimiento de algún documento fechado con anterioridad. De ahí que sea importante estudiarlos, y que sus semejanzas y diferencias sean analizadas y puestas a discusión. Justamente las semejanzas permiten suponer que se tuvo como referencia un solo documento original, y sus diferencias hacen pensar que este original era más parecido al Códice de Huichapan que al de Jilotepec. Aquí, sin embargo, se plantea la primera contradicción: el Códice de Jilotepec es anterior al de Huichapan. En efecto, el de Jilotepec se escribió, aparentemente a finales del siglo XVI. Por lo que se refiere al de Huichapan, Alfonso Caso demostró que está pintado en papel europeo que se importó a mediados del siglo XVII

Desarrollo de los verticilos sexuales de Vanroyenella plumosa Novelo & Philbrick (Podostemaceae)

The vegetative body of Vanroyenella plumosa Novelo & Philbrick (subfamily Podostemoideae) is composed of roots, leaves and a dorsiventrally flattened thalloid stem which, in the reproductive stage of the life cycle, develops cavities containing fascicles of flowers. In this work the embryology of this species was studied. Floral development depends on the flower position in the vegetative body of the plant, the plant position on the rock and the water level in the river. Vanroyenella plumosa possesses two stamens with tetrasporangiate anthers; the anther wall formation is of the basic type. Tetrads are tetrahedral, and the pollen is bicellular. The gynoecium is bicarpelar and bilocular with axial placentation and has two stigmas with idioblasts whose vacuoles contain proteins and carbohydrates. The ovules are anatropous, bitegmic and tenuinucellate. The embryo sac is monosporic in its origin and tetracellular of the Apinagia type. In Vanroyenella floral development occurs in the interior of the stem while the plant is submerged, and it is during this very early stage that the male and female gametes are formed. When the water level recedes, the pedicels elongate and anthesis occurs above water. The ovary wall supports the seed development after the rest of the vegetative tissue has died.El cuerpo vegetativo de Vanroyenella plumosa Novelo & Philbrick (subfamilia Podostemoideae) posee raíz, hojas y un tallo taloide dorsiventralmente aplanado que, durante la etapa reproductora, desarrolla cavidades ocupadas por fascículos florales. En este trabajo se estudió la embriología de esta especie y se relacionó el desarrollo floral con la posición de las flores en el cuerpo vegetativo de la planta, la posición de la planta sobre la roca y de la planta con el nivel del agua. Vanroyenella plumosa presenta dos estambres cuyas anteras son tetrasporangiadas, con un desarrollo de la pared de tipo Básico, tétradas tetraédricas y polen bicelular. El gineceo es bicarpelar y bilocular con placentación axial y presenta dos estigmas con idioblastos cuya vacuola contiene proteínas y carbohidratos. Los óvulos son anátropos, bitégmicos y tenuinucelados. El saco embrionario es monospórico y tetracelular, del tipo Apinagia. En Vanroyenella el desarrollo floral ocurre en el interior del tallo mientras la planta está sumergida, allí se forman los gametos en etapas muy tempranas. Cuando el nivel del agua baja, los pedicelos se alargan y sobreviene la antesis, en el ambiente aéreo. La pared del ovario sostiene el desarrollo de las semillas una vez que el resto del tejido vegetativo ha muerto

An efficiency comparison of different in vitro fertilization methods: IVF, ICSI, and PICSI for embryo development to the blastocyst stage from vitrified porcine immature oocytes

Abstract Background Most studies carried out to evaluate recovery and development after porcine oocyte vitrification, reported better rates when cryopreserved in embryonic development stages or zygotes, but not in immature oocytes. For this reason, many studies are performed to improve immature oocyte vitrification protocols testing the use of different cryoprotectant concentrations, cooling devices, incubation times; but only a few of them have evaluated which fertilization procedure enhances blastocyst rates in vitrified oocytes. Therefore, this study was aimed to evaluate: 1) if the sperm selection with hyaluronic acid (HA) or polyvinylpyrrolidone (PVP) before injection could play a key role in increasing fertilization and blastocyst formation and 2) the embryo developmental ability and blastocyst production of porcine immature oocytes retrieved after vitrification-warming and co-cultured with granulosa cells during IVM, using different fertilization techniques: in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and conventional ICSI with hyaluronic acid (HA) sperm selection, known as physiological intracytoplasmic sperm injection (PICSI) and. Results Sperm selected with HA-PICSI displayed a higher percentage of live/acrosome reacted status compared to those in control and exposed to PVP. Higher dead/acrosome reacted rates were obtained after PVP exposure compared to control and HA. In oocytes, viability significantly decreased after IVM in vitrified oocytes. Besides, IVM rates were not different between control denuded oocytes cultured with granulosa cells (DO-GC) and vitrified oocytes. Regarding fertilization parameters, IVF showed higher percentages of total fertilization rate than those obtained by ICSI and PICSI. However, results demonstrate that PICSI fertilization increased the blastocysts formation rate in control DO-GC and vitrified oocytes compared to IVF and ICSI. Conclusions To achieve high blastocyst formation rates from vitrified GV oocytes, it is recommended that sperm should be selected with HA instead of PVP before injection since high viability and acrosome reaction rates were obtained. Also, PICSI fertilization was the best method to produce higher blastocyst rates compared to the IVF and ICSI procedures

Prenatal Stress Reduces Learning and Memory in Pre-pubertal, Young, and Adult Rats of Both Sexes

Prenatal stress (PS) induced by immobilization produces defi ciencies in spatial learning and information retrieval. These defi ciencies seem to be larger in males than in females, and have been explained as an effect of fetal exposure to high concentrations of maternal corticosterone during stress response. However, the effects of PS have only been assessed at a single time point and/or sex. In this work, the effect of PS on spatial learning and memory induced by immersion in cold water was evaluated in young and adult rats of both sexes. PS was induced during gestational days 15 through 21. Corticosterone in dams, body weight, corticosterone, learning and memory were assessed in male and female offspring at one, two, and three months of postnatal life. Results showed that escape latencies of PS rats of both sexes were longer as compared to those of control groups and that the number of platformsite crossovers and time spent in the platform quadrant were lower in the PS animals as compared to the control groups. Corticosterone levels were higher in PS females and males compared with controls. The body weight was decreased only in PS males of one month of age. These results show that PS by immersion in cold water alters learning and memory processes in the offspring, regardless of sex or age, since the effects are similar in females and males during youth and adulthood. These behavioral effects are related to high serum corticosterone.</p

Fifteen minutes of daily contact with sexually active male induces ovulation, but delays it’s timing in seasonally anestrous goats

Remerciements : Inra, UMR 0085, plateforme de Phénotypage - Endocrinologie, 37380 Nouzilly, Centre Val de LoireThe present experiment was conducted to determine i) whether the sexually active bucks are able to stimulate the ovulatory activity of seasonal anestrous goats when the daily contact is reduced to 15 min per day during 15 days; and ii) the exact ovulatory activity in anestrous goats exposed to bucks for 2 h or less than 2 h per day during 15 days. One group of goats (n=15) was isolated from bucks. The other six groups (n= 15 each) were exposed to sexually active bucks (n= 1 each) for 15 min, 30 min, 1 h, 2 h, 4 h, or 24 h during 15 days. Goats with plasma concentrations of progesterone &gt; 0.5 ng/mL were considered to have ovulated. More than 93% of females exposed to bucks ovulated throughout the experiment regardless the duration of contact with males, whereas none of them ovulated in the isolated group (P &lt; 0.0001). The proportions of females that ovulated at least once did not differ among groups, as well as the proportions of goats that displayed normal or short ovulatory cycles. The interval between the introduction of males and the first ovulation did not differ among groups of goats in contact with bucks for 15 min, 30 min, 1 h or 2 h. However, in these groups, this ovulation occurred about 2 days later than in females in contact with males during 4 h or 24 h (6.3 vs. 4.4 days; P &lt; 0.05). We conclude that 15 min of daily contact with sexually active bucks is sufficient to stimulate the ovulatory activity in seasonally anestrous goats, but the first ovulation is delayed in goats exposed to males for 2 h per day or less during 15 days in comparison with those in contact with males for 4 h or 24 h per day