Effects and Mechanism of Two Nanoparticles (Titanium Dioxide and Silver) to Moina mongolica Daday (Crustacea, Cladocera)

The nearshore and estuary are the main gathering areas of nanoparticles (NPs), and salinity change is a crucial characteristic in these marine areas. Moina mongolica Daday is an important open-ended bait in the nearshore aquaculture environment. Investigating the toxicity mechanism of NPs to M. mongolica under different salinity conditions is crucial to exploring the biological impact of NPs in the nearshore environment. Two typical metal oxide and metal NPs of TiO2 and Ag were used in this study to test the acute, chronic, and reproductive toxicities of M. mongolica (Cladocera) in marine environments of different salinity gradients. The toxic effects and mechanisms of the two NPs on M. mongolica were discussed by ecotoxicology and transcriptional analysis, respectively. A total of 27,274 genes were assembled, and 11,056 genes were successfully compared. Results suggested that TiO2 and Ag NPs showed particle toxicity with oxidation generation and immune emergencies on M. mongolica. Compared with TiO2, Ag NPs showed strong toxicity with reproductive toxicity due to the release of Ag+, resulting in a reduction in reproduction, which is a decrease in the number of offspring and the rm. Critical DEGs involved in carapace showed carapace damage of M. mongolica, due to adhesion and accumulation (approximately 40%–60% of all accumulation) on carapace, which was one of the toxic mechanisms of the two NPs. The salinity factor caused the aggregation of both NPs, and Ag+ release of Ag NPs. The toxicity of TiO2 NPs to M. mongolica increases with salinity, but that of Ag NPs decreases

Kisspeptin Signalling in the Hypothalamic Arcuate Nucleus Regulates GnRH Pulse Generator Frequency in the Rat

Kisspeptin and its G protein-coupled receptor (GPR) 54 are essential for activation of the hypothalamo-pituitary-gonadal axis. In the rat, the kisspeptin neurons critical for gonadotropin secretion are located in the hypothalamic arcuate (ARC) and anteroventral periventricular (AVPV) nuclei. As the ARC is known to be the site of the gonadotropin-releasing hormone (GnRH) pulse generator we explored whether kisspeptin-GPR54 signalling in the ARC regulates GnRH pulses.We examined the effects of kisspeptin-10 or a selective kisspeptin antagonist administration intra-ARC or intra-medial preoptic area (mPOA), (which includes the AVPV), on pulsatile luteinizing hormone (LH) secretion in the rat. Ovariectomized rats with subcutaneous 17β-estradiol capsules were chronically implanted with bilateral intra-ARC or intra-mPOA cannulae, or intra-cerebroventricular (icv) cannulae and intravenous catheters. Blood samples were collected every 5 min for 5–8 h for LH measurement. After 2 h of control blood sampling, kisspeptin-10 or kisspeptin antagonist was administered via pre-implanted cannulae. Intranuclear administration of kisspeptin-10 resulted in a dose-dependent increase in circulating levels of LH lasting approximately 1 h, before recovering to a normal pulsatile pattern of circulating LH. Both icv and intra-ARC administration of kisspeptin antagonist suppressed LH pulse frequency profoundly. However, intra-mPOA administration of kisspeptin antagonist did not affect pulsatile LH secretion.These data are the first to identify the arcuate nucleus as a key site for kisspeptin modulation of LH pulse frequency, supporting the notion that kisspeptin-GPR54 signalling in this region of the mediobasal hypothalamus is a critical neural component of the hypothalamic GnRH pulse generator

Aequorea taiwanensis n. sp. (Hydrozoa,Leptomedusae) and mtCOI sequence analysis for the genus Aequorea

【中文摘要】 Aequorea taiwanensis,a new hydrozoan species from the Taiwan Strait was described using morphological and molecular characteristics.Both morphological and mitochondrial cytochrome oxidase subunit I(mtCOI) data supported A.taiwanensis n.sp.as a valid species.Sequence divergence and genetic distance of A.taiwanensis n.sp.,A.papillata and A.conica were analysed based on the mtCOI gene sequences.The mtCOI sequences from these three species of the genus Aequorea showed high variation frequency,with sequence dive... 【英文摘要】 Aequorea taiwanensis,a new hydrozoan species from the Taiwan Strait was described using morphological and molecular characteristics.Both morphological and mitochondrial cytochrome oxidase subunit I(mtCOI) data supported A.taiwanensis n.sp.as a valid species.Sequence divergence and genetic distance of A.taiwanensis n.sp.,A.papillata and A.conica were analysed based on the mtCOI gene sequences.The mtCOI sequences from these three species of the genus Aequorea showed high variation frequency,with sequence dive..

sp.1 (Cnidaria, Scyphozoa)

The genus Aurelia is one of the major contributors to jellyfish blooms in coastal waters, possibly due in part to hydroclimatic and anthropogenic causes, as well as their highly adaptive reproductive traits. Despite the wide plasticity of cnidarian life cycles, especially those recognized in certain Hydroza species, the known modifications of Aurelia life history were mostly restricted to its polyp stage. In this study, we document the formation of polyps directly from the ectoderm of degenerating juvenile medusae, cell masses from medusa tissue fragments, and subumbrella of living medusae. This is the first evidence for back-transformation of sexually mature medusae into polyps in Aurelia sp.1. The resulting reconstruction of the schematic life cycle of Aurelia reveals the underestimated potential of life cycle reversal in scyphozoan medusae, with possible implications for biological and ecological studies

Stress-induced inhibition of LH pulses in female rats:role of GABA in arcuate nucleus

Stress exerts profound inhibitory effects on reproductive function by suppression of the pulsatile release of GnRH and therefore LH. Besides the corticotrophin-releasing factor (CRF), this effect also might be mediated via GABAergic signaling within the arcuate nucleus (ARC) since its inhibitory effects on LH pulses and increased activity during stress. In the present study, we investigated the role of endogenous GABAergic signaling within the ARC in stress-induced suppression of LH pulses. Ovariectomised oestradiol-replaced rats were implanted with bilateral and unilateral cannulae targeting toward the ARC and lateral cerebral ventricle respectively. Blood samples (25 μl) were taken via chronically implanted cardiac catheters every 5 min for 6 h for measurement of LH pulses. Intra-ARC infusion of GABAAreceptor antagonist, bicuculline (0.2 pmol in 200 nl artificial cerebrospinal fluid (aCSF) each side, three times at 20-min intervals) markedly attenuated the inhibitory effect of lipopolysaccharide (LPS; 25 μg/kg i.v.) but not restraint (1 h) stress on pulsatile LH secretion. In contrast, restraint but not LPS stress-induced suppression of LH pulse frequency was reversed by intra-ARC administration of GABABR antagonist, CGP-35348 (1.5 nmol in 200 nl aCSF each side, three times at 20-min intervals). Moreover, intra-ARC application of either bicuculline or CGP-35348 attenuated the inhibitory effect of CRF (1 nmol in 4 μl aCSF, i.c.v.) on the LH pulses. These data indicate a pivotal and differential role of endogenous GABAAand GABABsignaling mechanisms in the ARC with respect to mediating immunological and psychological stress-induced suppression of the GnRH pulse generator respectively.</jats:p

Species information of <i>Aurelia</i> sp.1 in Xiamen Bay, East China Sea.

<p>A: sampling location for <i>Aurelia</i> sp.1 from Xiamen Bay, which was indicated as the red dot in the map. B and C: Neighbor-Joining cladogram of <i>Aurelia</i> based on mitochondrial COI (B) and nuclear ITS (C) sequences, bootstrap values higher than 70 were shown close to each branch node, number of sequences belonging to the same species were indicated in the bracket following the species name, and sequences of <i>Aurelia</i> sp.1 obtained in this study were highlighted.</p

Schematic life cycle of <i>Aurelia</i>.

<p>Normal development traits and stages were presented with black illustrates and arrows, whereas modifications of the typical life cycle were drawn with colored objects (Red: process described in this study; others: process published with references herein). I: direct development of planula; II: production of elongated stolons, podocysts, and free-swimming propagules from scyphistoma; III: reverse development of ephyra; IV: direct polyp formation from degenerating juvenile medusa and medusa tissue fragments; V: direct polyp formation from living medusa; VI: polyp colony release from medusa-polyp complex.</p

Direct polyp formation from degenerating juvenile <i>Aurelia</i> sp.1 medusae.

<p>A-D: normal development from ephyrae to juvenile medusae, showing individuals of newly released (A), 5-day (B), 10-day (C) and 20-day (D) old, respectively. E, F: aboral (E) and oral (F) view of a 25-day old medusa after 5 days post settlement. G-L: juvenile medusae during reverse transformation. Scale bars = 0.2 mm (A, B); 0.5 mm (C-L). Arrows showed degeneration of medusa tentacles (E), occurrence of polyp stolon (G), development of polyp tentacles (H), and remains of medusa rhopalia (I and J).</p

Direct polyp formation from living <i>Aurelia</i> sp.1 medusae.

<p>A, D: 3-month old medusae. B, C: the same individual as (A) after 75 days, showing the thickened layers and projecting pointed ends at different scales. E-G: the same individual as (D) after 75 days, showing the derived colonies (E and F) and thickened layers (G) at different scales. H-L: proportions of living medusae at different stages of direct polyp formation. Scale bars = 1 cm (A, B, D, E); 5 mm (C, F, G-L). Arrows showed transformation process at different stages.</p

Direct polyp formation from <i>Aurelia</i> sp.1 medusae tissue fragments.

<p>A: a 25-day old medusa. B: juvenile medusae 5 days after settlement. C: oral arms 1 month after settlement. D-G: tissue fragments from juvenile medusae. H-K: polyps arose from juvenile medusae fragments. L: a 1-year old male medusa (collected from the field). M: settled broken or fragmented adult medusae. N: oral arms 3 months after settlement. O-R: tissue fragments from adult medusae. S-V: polyps arose from adult medusae fragments. Scale bars = 1 mm (A, B, C); 0.2 mm (D-G); 0.1 mm (H-K, O-V); 1 cm (L-N). Arrows showed newly developed polyps.</p