3 research outputs found
Human Fetal Exposure to Triclosan and Triclocarban in an Urban Population from Brooklyn, New York
Triclosan
(TCS) and triclocarban (TCC) are antimicrobial agents
formulated in a wide variety of consumer products (including soaps,
toothpaste, medical devices, plastics, and fabrics) that are regulated
by the U.S. Food and Drug Administration (FDA) and U.S. Environmental
Protection Agency. In late 2014, the FDA will consider regulating
the use of both chemicals, which are under scrutiny regarding lack
of effectiveness, potential for endocrine disruption, and potential
contribution to bacterial resistance to antibiotics. Here, we report
on body burdens of TCS and TCC resulting from real-world exposures
during pregnancy. Using liquid chromatography tandem mass spectrometry,
we determined the concentrations of TCS, TCC, and its human metabolites
(2′-hydroxy-TCC and 3′-hydroxy-TCC) as well as the manufacturing
byproduct (3′-chloro-TCC) as total concentrations (Σ−)
after conjugate hydrolysis in maternal urine and cord blood plasma
from a cohort of 181 expecting mother/infant pairs in an urban multiethnic
population from Brooklyn, NY recruited in 2007–09. TCS was
detected in 100% of urine and 51% of cord blood samples after conjugate
hydrolysis. The interquartile range (IQR) of detected TCS concentrations
in urine was highly similar to the IQR reported previously for the
age-matched population of the National Health and Nutrition Examination
Survey (NHANES) from 2003 to 2004, but typically higher than the IQR
reported previously for the general population (detection frequency
= 74.6%). Urinary levels of TCC are reported here for the first time
from real-world exposures during pregnancy, showing a median concentration
of 0.21 μg/L. Urinary concentrations of TCC correlated well
with its phase-I metabolite ∑-2′-hydroxy-TCC (<i>r</i> = 0.49) and the manufacturing byproduct ∑-3′-chloro-TCC
C (<i>r</i> = 0.79), and ∑-2′-hydroxy-TCC
correlated strongly with ∑-3′-hydroxy-TCC (<i>r</i> = 0.99). This human biomonitoring study presents the first body
burden data for TCC from exposures occurring during pregnancy and
provides additional data on composite exposure to TCS (i.e., from
both consumer-product use and environmental sources) in the maternal–fetal
unit for an urban population in the United States
Responses of Nannochloropsis oceanica IMET1 to Long-Term Nitrogen Starvation and Recovery
National Basic Research Program of China (973 Program) [2010CB428702]; National Natural Science Foundation of China [41206126]; University of Maryland Center for Environmental Sciences [4755]; Institute of Marine and Environmental Technology [13106]The Nannochloropsis genus contains oleaginous microalgae that have served as model systems for developing renewable biodiesel. Recent genomic and transcriptomic studies on Nannochloropsis species have provided insights into the regulation of lipid production in response to nitrogen stress. Previous studies have focused on the responses of Nannochloropsis species to short-term nitrogen stress, but the effect of long-term nitrogen deprivation remains largely unknown. In this study, physiological and proteomic approaches were combined to understand the mechanisms by which Nannochloropsis oceanica IMET1 is able to endure long-term nitrate deprivation and its ability to recover homeostasis when nitrogen is amended. Changes of the proteome during chronic nitrogen starvation espoused the physiological changes observed, and there was a general trend toward recycling nitrogen and storage of lipids. This was evidenced by a global down-regulation of protein expression, a retained expression of proteins involved in glycolysis and the synthesis of fatty acids, as well as an up-regulation of enzymes used in nitrogen scavenging and protein turnover. Also, lipid accumulation and autophagy of plastids may play a key role in maintaining cell vitality. Following the addition of nitrogen, there were proteomic changes and metabolic changes observed within 24 h, which resulted in a return of the culture to steady state within 4 d. These results demonstrate the ability of N. oceanica IMET1 to recover from long periods of nitrate deprivation without apparent detriment to the culture and provide proteomic markers for genetic modification