Maternal oral exposure to low-dose BPA accelerates the onset of puberty by promoting prepubertal Kiss1 expression in the AVPV nucleus of female offspring.

As the incidence of precocious puberty has risen in recent years and the age at puberty onset is younger, children may be at increased risk for health consequences associated with the early onset of puberty. Bisphenol A (BPA) is recognized as an endocrine disruptor chemical that is reported to induce precocious puberty. The effect of BPA exposure modes, times, and doses (especially low dose) were controversial. In the present study, we evaluated the potential effects of maternal exposure to low-dose BPA on the hypothalamus, particularly on the arcuate (ARC) nucleus and anteroventral periventricular (AVPV) nucleus during peri-puberty in offspring of BPA-treated rats. Pregnant rats were exposed to corn oil vehicle, 0.05 mg·kg-1·day-1 BPA, or 5 mg·kg-1·day-1 from gestation day 1 (GD1) to postnatal day 21 (PND21) by daily gavage. Body weight (BW), vaginal opening (VO), ovarian follicular luteinization, and relevant hormone concentrations were measured; hypothalamic Kiss1 and GnRH1 levels by western immunoblot analysis were also assessed as indices of puberty onset. During or after exposure, low-dose BPA restricted BW after birth (at PND1 and PND5), and subsequently accelerated puberty onset by promoting the expression of prepubertal Kiss1 and GnRH1 in the AVPV nucleus on PND30, leading to advanced VO, an elevation in LH and FSH concentrations (on PND30). We also noted increased BW on PND30 and PND35. Maternal oral exposure to low-dose BPA altered the BW curve during the neonatal and peripubertal periods, and subsequently accelerated puberty onset by promoting prepubertal Kiss1 expression in the AVPV nucleus.

Auxin alleviates cadmium toxicity by increasing vacuolar compartmentalization and decreasing long-distance translocation of cadmium in Poa pratensis.

Kentucky bluegrass (Poa pratensis L.) hyperaccumulates cadmium (Cd) and exhibits a hypertolerance. Thus, it has potential for the phytoremediation of Cd-containing soil. Auxin signaling is involved in the response to Cd stress. However, the mechanisms of auxin-mediated detoxification and Cd translocation in plants remain unclear. This study aimed to investigate the effects of exogenous application of indole-3-acetic acid (IAA) on the Cd translocation, subcellular Cd distribution, chemical forms of Cd, and transcriptional regulation of Kentucky bluegrass. The results showed that the exogenous application of IAA increased the amount of organelle-bound Cd and vacuole-compartmentalized Cd in root cells, reduced the Cd concentration in the leaf tissues (epidermis, mesophyll, and vascular bundle) and root tissues (rhizodermis and cortex) but increased in the stele, and alleviate Cd-induced leaf chlorosis and growth inhibition. The expression of genes associated with Cd transporters (ABCs, ZIPs, NASs, OPTs, and YSLs), phosphatases, oxalate decarboxylases and lignin biosynthesis were significantly regulated by exogenous IAA under Cd stress. A positive regulation of phosphatases and oxalate decarboxylases genes related to an increase in phosphate- and oxalate-bound Cd, as well as a decrease in pectate- and protein-bound Cd and inorganic Cd, thereby contributing to a decrease in Cd phytotoxicity. The significant regulation of Cd transporters associated with decreasing the long-distance translocation of Cd, and the activation of lignin biosynthesis may contribute to the development of root endodermal barriers and increase the deposition of undissolved Cd phosphates and oxalate-bound Cd in the stele. These results revealed the important role of auxin in Cd detoxification and translocation in Kentucky bluegrass and they provide a theoretical basis for the phytoremediation of Cd-containing soil.

Comparative transcriptome analysis of resistant and susceptible Kentucky bluegrass varieties in response to powdery mildew infection.

BACKGROUND: Poa pratensis is one of the most common cold-season turfgrasses used for urban turf building, and it is also widely used in ecological environment management worldwide. Powdery mildew is a common disease of P. pratensis. To scientifically and ecologically control lawn powdery mildew, the molecular mechanism underlying the response of P. pratensis to powdery mildew infection must better understood. RESULTS: To explore molecular mechanism underlying the response of P. pratensis to powdery mildew infection, this study compared physiological changes and transcriptomic level differences between the highly resistant variety 'BlackJack' and the extremely susceptible variety 'EverGlade' under powdery mildew infection conditions. We analyzed DEGs using reference canonical pathways in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and the results showed that "starch and sucrose metabolism", "photosynthesis" and "fatty acid metabolism"pathways were only enriched in 'BlackJack', and the expression of DEGs such as HXK, INV, GS, SS, AGpase and ß-amylase in "starch and sucrose metabolism" pathway of 'BlackJack' were closely related to powdery mildew resistance. Meanwhile, compared with 'EverGlade', powdery mildew infection promoted synthesis of sucrose, expression of photosynthesis parameters and photosynthesis-related enzymes in leaves of 'BlackJack' and decreased accumulation of monosaccharides such as glucose and fructose. CONCLUSIONS: This study identified the key metabolic pathways of a P. pratensis variety with high resistance to powdery mildew infection and explored the differences in physiological characteristics and key genes related to sugar metabolism pathways under powdery mildew stress. These findings provide important insights for studying underlying molecular response mechanism.

Bisphenol A exposure advances puberty onset by changing Kiss1 expression firstly in arcuate nucleus at juvenile period in female rats.

Bisphenol A (BPA) is ubiquitous in the environment and its adverse effects on precocious puberty have been reported. But its mechanism is not clear. In the present study, the potential effects of BPA on endocrine functions of hypothalamus, especially in the arcuate (ARC) nucleus and anteroventral periventricular (AVPe) nucleus, were studied from postnatal day 15 (PND15) to PND35 in female Sprague-Dawley (SD) rats. Neonatal rats were exposed to 0.5 mg·kg-1·day-1 BPA or corn oil vehicle from PND1 to PND14 via intramuscular injection. From PND20 to PND 25, BPA caused enrichment of H3K4me2 and H3K4me3 at Kiss1 promoter, concurrent with elevated gene expressions of Kiss1 and GnRH1 in ARC and strikingly increased serum E2 levels in BPA group on PND25. Until PND30, BPA induced obviously overexpression of Kiss1 and GnRH1 in AVPe nucleus. Subsequently, the vagina opening and first ovulation had occurred earlier in rats with BPA exposure in respect to vehicle by PND35. In this study, it is suggested that the effects of BPA on precocious puberty may be due to its action to activate Kiss1 gene in ARC during the juvenile period (from PND20 to PND25) firstly, subsequently to evoke the AVPe neurons, resulting in precocious puberty in the end.

Enantioselective Cobalt-Catalyzed Hydroboration of Ketone-Derived Silyl Enol Ethers.

Catalytic asymmetric hydroboration of alkenes is a powerful tool for the synthesis of natural products, agrochemicals, and pharmaceuticals via the versatile transformations of chiral alkyl boronic esters. However, the scope of available alkenes is limited to styrenes, activated alkenes, and compounds with directing groups. The catalytic enantioselective hydroboration of heteroatom-substituted alkenes is rarely explored and those catalyzed by earth-abundant metals are yet to be reported. Herein, we report a cobalt-catalyzed asymmetric hydroboration of ketone-derived silyl enol ethers and provide a convenient approach to access valuable enantiopure ß-hydroxy boronic esters. This protocol features mild reaction conditions, a broad substrate scope, and excellent enantioselectivities (up to 99 % ee). This approach was applied in the successful synthesis of salmeterol and albuterol, demonstrating its potential to streamline complex molecule synthesis.

Enantioselective Rh-Catalyzed Hydroboration of Silyl Enol Ethers.

The asymmetric hydroboration of alkenes has proven to be among the most powerful methods for the synthesis of chiral boron compounds. This protocol is well suitable for activated alkenes such as vinylarenes and alkenes bearing directing groups. However, the catalytic enantioselective hydroboration of O-substituted alkenes has remained unprecedented. Here we report a Rh-catalyzed enantioselective hydroboration of silyl enol ethers (SEEs) that utilizes two new chiral phosphine ligands we developed. This approach features mild reaction conditions and a broad substrate scope as well as excellent functional group tolerance, and enables highly efficient preparation of synthetically valuable chiral borylethers.

Physiological and transcriptome analysis of Poa pratensis var. anceps cv. Qinghai in response to cold stress.

BACKGROUND: Low temperature limits the growth and development and geographical distribution of plants. Poa pratensis is a cool-season turfgrass mainly grown in urban areas. However, low winter temperature or cold events in spring and autumn may cause P.pratensis mortality, affecting the appearance of lawns. P.pratensis var. anceps cv. Qinghai (PQ) is widely distributed in the Qinghai-Tibet Plateau above 3000 m. PQ has greater cold tolerance than the commercially cultivated P.pratensis varieties. However, existing studies on the response mechanism of PQ to low temperatures have mainly focused on physiological and biochemical perspectives, while changes in the PQ transcriptome during the response to cold stress have not been reported. RESULTS: To investigate the molecular mechanism of the PQ cold response and identify genes to improve the low-temperature tolerance of P.pratensis, we analyzed and compared the transcriptomes of PQ and the cold-sensitive P.pratensis cv. 'Baron' (PB) under cold stress using RNA sequencing. We identified 5996 and 3285 differentially expressed genes (DEGs) between the treatment vs control comparison of PQ and PB, respectively, with 5612 DEGs specific to PQ. Based on the DEGs, important Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, such as "starch and sucrose metabolism", "protein processing in endoplasmic reticulum", "phenylalanine metabolism" and "glycolysis/gluconeogenesis" were significantly enriched in PQ, and "starch and sucrose metabolism", "phenylpropanoid biosynthesis", "galactose metabolism" and "glutathione metabolism" were significantly enriched in PB. In addition, the "glycolysis" and "citrate cycle (TCA cycle)" pathways were identified as involved in cold tolerance of P.pratensis. CONCLUSIONS: As we know, this is the first study to explore the transcriptome of P.pratensis var. anceps cv. Qinghai. Our study not noly provides important insights into the molecular mechanisms of P.pratensis var. anceps cv. Qinghai responds to cold stress, but also systematically reveals the changes of key genes and products of glycolysis and TCA cycle in response to cold stress, which is conductive to the breeding of cold-tolerance P.pratensis genotype.

Rhodium-Catalyzed Remote Isomerization of Alkenyl Alcohols to Ketones.

We develop herein an efficient rhodium-catalyzed remote isomerization of aromatic and aliphatic alkenyl alcohols into ketones. This catalytic process, with a commercially available catalyst and ligand ([RhCl(cod)]2 and Xantphos), features high efficiency, low catalyst loading, good functional group tolerance, a broad substrate scope, and no (sub)stoichiometric additive. Preliminary mechanistic studies suggest that this transformation involves an iterative dissociative ß-hydride elimination-migration insertion process.

Nucleophilic Amination and Etherification of Aryl Alkyl Thioethers.

A transition-metal-free protocol capable of synthesizing diarylated aniline derivatives is reported. This method could be further employed to prepare aryl alkyl ethers. A wide range of thioethers, anilines, as well as alcohols were tolerated thanks to the mild reaction conditions. The strength of our method was demonstrated by performing a gram-scale reaction (20 mmol) followed by conversion of the nitrile group into synthetically useful aldehyde, ketone, and carboxylic acid.

[Clinical observation on cervical spondylosis of neck type treated with acupuncture at original and terminal points of trapezius].

OBJECTIVE: To compare the differences of therapeutic effect of cervical spondylosis of neck type treated with acupuncture at starting and ending points of trapezius and the Jiaji (EX-B 2) points. METHODS: Sixty cases of cervical spondylosis of neck type were randomly divided into an observation group and a control group, 30 cases in each group. In observation group, the acupoints related with starting and ending points of trapezius, such as Tianzhu (BL 10), Fengchi (GB 20), Quyuan (SI 13), Jugu (LI 16) and Ashi were punctured; in control group, Jiaji (EX-B 2) points of neck were punctured. The treatments were applied 5 times a week and 2 weeks made one course. The international simplified McGill scale was adoped to assess the scores of Pain Rating Index (PRI), Visual Analogue Scale (VAS) and Present Pain Intensity (PPI) before treatment and after one course treatment, and the therapeutic effects were measured. RESULTS: After treatment, all the scores were obviously reduced in both groups: (all P < 0.01), and the PRI-sensory subscore, PRI-affective subscore and total score in observation group reduced more obviously than those in control group, and there were statistically significant differences between groups (all P < 0.01). There were no statistically significant differences between groups in VAS and PPI score (both P > 0.05). The total effective rate of 96.7% (29/30) in observation group was superior to that of 70.0% (21/30) in control group (P < 0.01). CONCLUSION: The therapeutic effect of cervical spondylosis of neck type treated with acupuncture at the starting and ending points of trapezius is positive, which is better than that of acupuncture at the Jiaji (EX-B 2) points.