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This study investigated the anti-estrogenic effects of chronic exposure to a new marine pollutant, semicarbazide (SMC; 1, 10, and 100 μg/L), in female Paralichthys olivaceus , as well as the associated mechanism. After 130 days of exposure, plasma 17β-estradiol and testosterone concentrations, and hepatic estrogen receptors, vitellogenin, and choriogenin mRNA levels decreased significantly in SMC-exposed groups. Moreover, down-regulation of genes in the hypothalamic-pituitary-gonadal axis, including gonadotropin-releasing hormone, gonadotropic hormones and their receptors, the steroidogenic acute regulatory protein, 17α-hydroxylase, 17β-hydroxysteroid dehydrogenase, and cytochrome P450 19A, was observed after SMC exposure. Furthermore, the kisspeptin/g protein-coupled receptor 54 (kiss/gpr54) system and gamma-aminobutyric acid-ergic (GABAergic) system were also affected by SMC: SMC significantly down-regulated mRNA expression of kiss2 , gpr54 , and the GABA synthesis enzyme gad67 . Our results demonstrated for the first time that environmentally relevant concentrations of SMC exerted anti-estrogenicity in female flounders, providing theoretical support for ecological risk assessments of SMC in marine environments. [ABSTRACT FROM AUTHOR]

Semicarbazide (SMC) is a carcinogenic and genotoxic substance that has been found in aquatic systems. SMC may also cause thyroid follicular epithelial cell injury in rats, but the thyroid-disrupting properties of SMC and its potential mechanisms remain unclear. In this study, we exposed fertilized eggs of Japanese flounder ( Paralichthys olivaceus ) to 1, 10, 100, and 1000 μg/L SMC for 55 d to assess the impact of SMC exposure on the thyroid system. The number of larvae in each metamorphic stage was counted, the concentrations of whole-body thyroid hormones (THs) 3,5,3′-triiodothyronine (T3) and thyroxine (T4) were measured, and the transcription levels of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis and gamma-aminobutyric acid (GABA) synthesis were quantified. The results showed that 10 μg/L SMC significantly increased whole-body T3 levels, and 100 and 1000 μg/L SMC markedly enhanced whole-body T4 and T3 levels. Furthermore, 100 μg/L SMC exposure shortened the time it took for flounder larvae to complete metamorphosis by 2 d as compared to the control group. Thus, this study demonstrated that SMC exerted thyroid-disrupting effects on Japanese flounder. SMC-mediated stimulation of TH levels was primarily related to transcriptional alterations of pituitary-derived thyroid stimulating hormone β-subunit ( tshβ ) and hepatic deiodinase ( id ). In the 10 and 100 μg/L SMC exposure groups, the increased TH levels may have resulted from inhibition of TH metabolism caused by down-regulation of id3 mRNA expression, while at 1000 μg/L SMC-exposed group, up-regulation of tshβ and id1 transcripts was expected to enhance the synthesis of T4 and the conversion of T4 to T3 and, consequently, result in higher T4 and T3 levels. In addition, 1000 μg/L SMC-induced down-regulation in glutamic acid decarboxylase gad65 and gad67 transcription may have also contributed to the increased TH levels. The thyroid-disrupting effects of 10 and 100 μg/L SMC indicated that environmentally relevant concentrations of SMC posed potential environmental risks to aquatic organisms. Overall, our results demonstrated for the first time that SMC exhibited thyroid-disrupting properties by affecting the HPT axis and GABA synthesis, providing theoretical support for environmental risk assessment. [ABSTRACT FROM AUTHOR]

Semicarbazide (SEM), an industrial raw material and the marker residue of nitrofurazone as a veterinary drug, has become a new type of marine pollutant. A standard method (ultra-performance liquid chromatography–tandem mass spectrometry, UPLC–MS/MS) was used to analyze SEM in seawater, sediment, and shellfish. A series of sections and stations were set up in radical distribution in western Laizhou Bay, with six voyages and 150 monitoring samples. The concentrations of SEM in seawater and shellfish were 10 − 11 and 10 − 10 kg/L, respectively, and no SEM was detected in the sediment. Distribution characteristics at each state, temporal and spatial trends, multivariate analyses, and the causes were analyzed to assess the pollution level, which aimed to offer a database for drafting the national baseline values of SEM in seawater and sediment in future. The data obtained could be used for integrated watershed management of marine environment and economic activities for constructing a blue economic zone of Shandong Peninsula in China. [ABSTRACT FROM AUTHOR]

Malaria and lymphatic filariasis are two of the most common identifiable mosquito-borne parasitic diseases worldwide. Mosquito-borne disease is believed to be responsible for approximately 1 million deaths per year. Such diseases are controlled by use of insecticides; however, these may have undesired effects on non-target organisms. We therefore sought a suitable larvicidal compound that could replace insecticides by evaluating copper(II) complexes for larvicidal activity against Anopheles subpictus and Culex quinquefasciatus . Larvicidal bioassays were performed with five batches of 20 mosquito larvae in 249 mL water and 1.0 mL of complexes of the precursor [Cu(phen)( l -Thr)(H 2 O)](ClO 4 ) with semicarbazide, thiosemicarbazide, urea or thiourea; the control was dechlorinated tap water. The number of dead larvae was counted after 24 h of exposure. Dose–response assays were performed at concentrations ranging from 10.0 to 0.625 mg/L of the complexes. The complex with urea had the best larvicidal activity against C. quinquefasciatus and A. subpictus at all concentrations. Copper(II) complexes have potential larvicidal activity, and that with urea had dose-dependent activity. [ABSTRACT FROM AUTHOR]

A series of 1-(substitutedbenzylidene)-4-(4-(2-(methyl/phenyl)-4-oxoquinazolin-3(4 H )-yl) phenyl)semicarbazide derivatives were synthesized with the aim of developing potential antimicrobials. It was characterized by FT-IR, 1 H NMR, Mass spectroscopy and elemental analysis. In addition, the in vitro antibacterial and antifungal properties were tested against some human pathogenic microorganisms by employing the disc diffusion technique and agar streak dilution method. All title compounds showed activity against the entire strain of microorganisms. The relationship between the functional group variation and the biological activity of the evaluated compounds were well discussed. Based on the results obtained, compound 5j was found to be very active compared to the rest of the compounds which were subjected to antimicrobial assay. [ABSTRACT FROM AUTHOR]

The article evaluates the effects of semicarbazide on the testicular morphology of rats. Results of the study showed normal testicular architecture in rats not treated with semicarbazide. However, rats treated with the agent showed testicular atrophy accompanied by the degeneration of the seminiferous tubules with shrunken and greatly depleted germ cells.

Schiff bases are considered as privileged ligand in coordination chemistry as they easily form stable complexes with most transition metal complexes. In this paper, a novel Schiff-base ligand derived from Curcumin and Semicarbazide (HMHC) and its transition metal [Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)] complexes were synthesized. FT-IR, UV–Vis, NMR, Mass, TG-DTA and ESR spectral techniques were used to confirm the structures of the metal chelates and ligand. The Schiff base behaves as a tridentate ligand with O and N donors and coordinates to metal ion via phenolic oxygens and azomethine nitrogen. The compositions of the ligand and its metal complexes have been established by elemental analysis. Spectral investigations suggested octahedral geometrical arrangement for all the metal(II) complexes, having 2:1 (L:M) stoichiometric ratio of the type [M(HMHC) 2 ]H 2 O. The Schiff base ligand and its metal complexes have been screened for antimicrobial evaluation towards some clinically important microorganisms. Result found that the metal complexes were more active than the ligand. Also anti-inflammatory activity of Schiff base complexes were studied by protein denaturation method and result reveals that Zn(II) complex shows more activity. [ABSTRACT FROM AUTHOR]