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Introduction: Emerging evidence suggesting diabetes -protective effects of dietary fiber intake. However, the underlying mechanisms are not fully understood. Hypothesis: We hypothesize that higher dietary fiber intake can alter gut microbial composition /functional capacity and host circulating metabolomic profile, which may contribute to lower risk of diabetes. Methods: We evaluated the associations of dietary fiber intake with gut microbiome (measured by shotgun metagenomic sequencing, n=2959) and serum metabolome (639 metabolites measured by untargeted metabolomic approach, n=6198) in the HCHS/SOL cohort. We further examined prospective associations of baseline fiber/microbial-associated metabolites with incident diabetes over 6-years follow-up. Results: We identified 39 bacterial genera associated with fiber intake, after adjustment for sociodemographic, behavioral, and clinical factors. 12 of these fiber-associated genera were related with diabetes (e.g. the fiber-associated Roseburia was inversely associated with diabetes, Fig.1A ). We identified 83 fiber-associated metabolites which were clustered into 13 modules in network, 7 of which were significantly associated with risk of diabetes ( Fig.1B ). Some of these diabetes-associated metabolite modules were also associated with fiber/diabetes-associated bacterial taxa ( Fig.1C ). In particular, indolepropionate module, and another module comprised of the pro-vitamins such as beta-cryptoxanthin, were positively associated with fiber (all PButyrivibrio (P Conclusion: Among US Hispanics/Latinos, higher fiber intake was associated with favorable profiles of gut microbiota and circulating metabolites for diabetes, suggesting a potential role of gut microbiota and related metabolites in the link between dietary fiber intake and risk of diabetes.

Sodium chloride, NaCl, is commonly used as a proxy for sea spray aerosols. However, field work has demonstrated that sea spray aerosols also often contain a significant organic component. In this work, we examine the effect of amino acids on the hygroscopic properties of NaCl aerosols using a Fourier transform infrared spectrometer coupled to a flow-cell apparatus. It is found that the effect can be drastically different depending on the nature of the amino acid. More hydrophilic amino acids such as glycine lead to continuous hygroscopic growth of internally mixed NaCl-amino acid aerosols generated from an equimolar precursor solution. However, more hydrophobic amino acids such as alanine do not significantly alter the hygroscopicity of NaCl aerosols. The hydropathy scale is found to be a good qualitative diagnostic for the effect that an amino acid will have on the hygroscopicity of NaCl.

Aluminum is a neurotoxic metal with known health effects in animals and humans. Glutathione-S-transferase (GST) genes and enzymes play a major role in detoxification of several heavy metals. Besides a direct relationship with oxidative stress; aluminum decreases GST enzyme activities. Using data from 116 Jamaican children; age 2–8 years; with Autism Spectrum Disorder (ASD) and 116 sex- and age-matched typically developing (TD) children; we investigated the association of polymorphisms in three GST genes (GSTP1; GSTM1; and GSTT1) with mean blood aluminum concentrations in children with and without ASD. Using log-transformed blood aluminum concentration as the dependent variable in a linear regression model; we assessed the additive and interactive effects of ASD status and polymorphisms in the three aforementioned GST genes in relation to blood aluminum concentrations. Although none of the additive effects were statistically significant (all p > 0.16); we observed a marginally significant interaction between GSTP1 Ile105Val (rs1695) and ASD status (p = 0.07); even after controlling for parental education level and consumption of avocado; root vegetables; and tuna (canned fish). Our findings indicate a significantly lower (p < 0.03) adjusted geometric mean blood aluminum concentration for TD children who had the Val/Val genotype (14.57 µg/L); compared with those with Ile/Ile or Ile/Val genotypes who had an adjusted geometric mean of 23.75 µg/L. However; this difference was not statistically significant among the ASD cases (p = 0.76). Our findings indicate that ASD status may be a potential effect modifier when assessing the association between GSTP1 rs1695 and blood aluminum concentrations among Jamaican children. These findings require replication in other populations.

Central adiposity, assessed by waist-to-hip ratio (WHR), has been associated with increased risk for cardiovascular disease. Both genetic and lifestyle factors, including physical inactivity, have been independently associated with WHR adjusted for BMI (WHRadjBMI). Physical activity (PA) is an important component of interventions for reducing or preventing central adiposity and has been shown to attenuate genetic influences on adiposity. However, the influence of PA on loci associated with central fat, independent of total body fat, is unknown. Our objective was to identify genetic variants whose effects on WHRadjBMI are modified by PA. To this end, we performed a meta-analysis of 36 genome-wide association studies, including 94,779 individuals of European ancestry. PA was standardized within each study (physically active and inactive) with the lowest quintile being defined as inactive. WHR was adjusted for BMI, age, and age 2 in men and women separately. Each study tested the SNP x PA interaction alone, and also tested the joint effects of both the interaction and SNP main effect using a two degree of freedom (2df) test. We pooled the results from individual studies using fixed-effects inverse variance weighted meta-analysis in men and women combined and separately. The 2df joint test reached genome-wide significance (p-8 ) for 23 loci, which included 11 novel loci for WHRadjBMI. Of these 11 loci, 7 were identified in women only, and one in men only. For each of the 23 loci, the association of the joint test was primarily driven by the SNP main effect on WHRadjBMI, rather than its interaction with PA. When we examined the interaction effects of the 23 loci, separately from main effect, the interaction reached nominal significance for 11 loci (5 of these were novel): e.g. established loci in/near LYPLAL1 (p=1.0e -7 ), VEGFA (p=3.8e -4 ), TBX15 (p=2.1e -5 in women), and RSPO3 (p=5.5e -3 ), and novel (in women only), in/near TMEM131 (p =3.2e -4 ), FAM186A (p=4.1e -4 ), and FLJ45974 (p=1.9e -3 ). In each case, the effect of the WHRadjBMI-increasing allele was smaller in the active group than in the inactive group; e.g. for the SNP near LYPLAL1 , in the active versus inactive: β[SE] = 0.024(0.036) vs 0.215(0.084), respectively. For the interaction term alone, no loci reached genome-wide significance, but a search at P-6 revealed 3 additional novel loci; 2 in men and women combined (in/near MYO18B and COX11P ) and 1 in men only (in SNW1 ). Our findings suggest that joint tests of main and interaction effects help elucidate the genetic basis of abdominal obesity and that genetic effects are larger in physically inactive compared to active individuals. To follow-up our initial findings, we are currently collecting data from 25 additional studies with genome-wide or Metabochip data.