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The mechanism of coffee eliciting erosion on teeth is unclear as few studies have investigated the direct effect of coffee on enamel and dentin structures. The present study identified how coffee, the most popular beverage worldwide, induces staining and erosion on teeth. We show the grade of erosion of molars and incisors in Sprague Dawley rats from two different age groups, young (four weeks) and old (six months). We quantified the concentration of metals contained in coffee by mass spectrometry (ICP-MS). To determine elemental content in enamel (i.e. superficial) and dentin (i.e. substructure), we used Laser-induced Breakdown Spectroscopy (LIBS) and X-ray fluorescence (XRF) spectroscopy, respectively. For LIBS, a significant decrease of Ca, P, and Na was observed in the young coffee group relative to age-matched controls, whereas a significant increase in Mn, Fe, and K was observed. In the old coffee group, a significant increase of Mg, Fe, and K was observed along with a decrease of Mg, Ca, P, Na, Sr and Zn. For XRF, a significant decrease of the Ca/P ratio in the coffee group was observed. Spectroscopy results were correlated with scanning electron microscopy (SEM) and histological analysis. The SEM analysis showed pores and open spaces between young and old coffee groups, respectively. Thinning of enamel layers, loss of continuity in the enamel-dentin-junction, and wide spaces in dentin tubules with coffee use was found histologically. Coffee induces decalcification of teeth that corresponds to erosion, exposing the dentin structure by reducing enamel. Coffee immersion demonstrated an intrinsic staining in dentin by metal deposition., (Copyright © 2018 Elsevier B.V. All rights reserved.)

On grounds of the especially limited numbers of identified gonad-specific or gonad-related genes of large yellow croaker Larimichthys crocea which may represent a major obstacle for the study of gonad development and sex differentiation, we initiated a sequencing program of Expressed Sequence Tags (ESTs) in large yellow croaker. In this study, we firstly constructed a normalized gonad cDNA library using the combination of SMART technique and DSN treatment. The titer of amplified cDNA library was 4.8x10(11) and the percentage of unique cDNA sequences of the library was 82.49%. 2916 unique cDNAs were clustered from the 3535 high quality ESTs. Among the 1785 ESTs which had significant homology with known genes in the NCBI database, about 64 significant gonad-related genes were found, accounting for 3.59% of the total unique cDNAs. Specifically, the testis-specific LRR gene and testis-specific chromodomain Y-like protein gene were identified from fish for the first time. Six gonad-related microsatellite-containing ESTs were identified from the 129 ESTs containing 149 microsatellites. Expression patterns of 10 of these gonad-related gene homologues in ovaries and testes were examined by qRT-PCR. The results will be powerful resources for our further investigation to establish the molecular mechanisms of gonad development and sex differentiation in large yellow croaker., (2010 Elsevier Inc. All rights reserved.)