The acute effect of propanil on reproductive hormones, ovarian gene expression and splenic cells in C57Bl/6 female mice

Earlier evidence indicates exposure to propanil, a post-emergent herbicide used on rice and wheat fields, increases the number of antibody-secreting cells (ASC) in the spleen of mice after immunization with heat-killed Streptococcus pneumoniae (HKSP, 2x108 CFU). Interestingly, an intact hypothalamic-pituitary-gonadal (HPG) axis is required for this immune response assessed on day 7-10 after immunization in female mice. Hence, an overarching premise is that propanil arbitrates the connection between the reproductive and immune system by altering the concentration of hormones involved in the HPG axis, which may then affect the populations of splenic cells. Hypotheses were tested with C57Bl/6 female mice vaccinated with HKSP and assigned among four treatment groups (6 mice each) in a 2x2 factorial arrangement. The first factor represented propanil treatment (propanil, control), and the second factor represented two periods (24h, 72h) of collection for blood, spleen, ovaries, and oviducts after immunization. At 24h, propanil decreased the number of splenocytes contrary to increased cell populations at day 7-10 observed in earlier experiments. Also, propanil increased serum concentrations of prolactin and progesterone but decreased estradiol, corroborated by corresponding changes in mRNA for steroid synthesis in ovaries. To determine if these effects depend on gonadotropin-releasing hormone (GnRH) receptor binding, we utilized the GnRH antagonist (antide; 60 µg s.q.), given to C57Bl/6 female mice before the same immunization with HKSP. In ovaries, antide increased gene expression of inflammatory and anti-inflammatory cytokines and markers (Csf1, Cxcl1, Cxcl10, Il-10, Irf-1, Tlr2), interacted with propanil effect in HKSP-challenged mice on the expression of serum amyloid A by reducing propanil’s effects. In the spleen, antide decreased the number of T-cells, and in the presence of HKSP decreased the number of B-cells and the percentage of monocytes and macrophages. Thus, GnRH receptors may be necessary for the acute responses (24 hours) to propanil and support a hypothesis that immune and reproductive systems interact in female mice challenged with the bacterial vaccine

A Window On The Earliest Star Formation: Extreme Photoionization Conditions of a High-Ionization, Low-Metallicity Lensed Galaxy at z~2

We report new observations of SL2SJ021737-051329, a lens system consisting of a bright arc at z=1.84435, magnified ~17x by a massive galaxy at z=0.65. SL2SJ0217 is a low-mass (M <10^9 M*), low-metallicity (Z~1/20 Z*) galaxy, with extreme star-forming conditions that produce strong nebular UV emission lines in the absence of any apparent outflows. Here we present several notable features from rest-frame UV Keck/LRIS spectroscopy: (1) Very strong narrow emission lines are measured for CIV 1548,1550, HeII 1640, OIII] 1661,1666, SiIII] 1883,1892, and CIII] 1907,1909. (2) Double-peaked LyA emission is observed with a dominant blue peak and centered near the systemic velocity. (3) The low- and high-ionization absorption features indicate very little or no outflowing gas along the sightline to the lensed galaxy. The relative emission line strengths can be reproduced with a very high-ionization, low-metallicity starburst with binaries, with the exception of He \ii, which indicates an additional ionization source is needed. We rule out large contributions from AGN and shocks to the photoionization budget, suggesting that the emission features requiring the hardest radiation field likely result from extreme stellar populations that are beyond the capabilities of current models. Therefore, SL2S0217 serves as a template for the extreme conditions that are important for reionization and thought to be more common in the early Universe.Comment: 28 pages, 16 figures, 8 tables, re-submitted to ApJ, comments welcom