Attentional bias for high-calorie food cues by the level of hunger and satiety in individuals with binge eating behaviors

Introduction

The abnormal hyperreactivity to food cues in individuals with binge eating behaviors could be regulated by hedonic or reward-based system, overriding the homeostatic system. The aim of the present study was to investigate whether attentional bias for food cues is affected by the level of hunger, maintaining the normal homeostatic system in individuals with binge eating behaviors.

Methods

A total of 116 female participants were recruited and divided into four groups: hungry-binge eating group (BE) (n = 29), satiated BE (n = 29), hungry-control (n = 29), satiated control (n = 29). While participants completed a free-viewing task on high or low-calorie food cues, visual attentional processes were recorded using an eye tracker.

Results

The results revealed that BE group showed longer initial fixation duration toward high-calorie food cues in both hunger and satiety condition in the early stage, whereas the control group showed longer initial fixation duration toward high-calorie food cues only in hunger conditions. Moreover, in the late stage, the BE group stared more at the high-calorie food cue, compared to control group regardless of hunger and satiety.

Discussion

The findings suggest that automatic attentional bias for food cues in individuals with binge eating behaviors occurred without purpose or awareness is not affected by the homeostatic system, while strategic attention is focused on high-calorie food. Therefore, the attentional processing of food cues in binge eating group is regulated by hedonic system rather than homeostatic system, leading to vulnerability to binge eating.

Endocytosing Escherichia coli as a Whole-Cell Biocatalyst of Fatty Acids

Whole cell biocatalysts can be used to convert fatty acids into various value-added products. However, fatty acid transport across cellular membranes into the cytosol of microbial cells limits substrate availability and impairs membrane integrity, which in turn decreases cell viability and bioconversion activity. Because these problems are associated with the mechanism of fatty acid transport through membranes, a whole-cell biocatalyst that can form caveolae-like structures was generated to promote substrate endocytosis. Caveolin-1 ( CAV1) expression in Escherichia coli increased both the fatty acid transport rate and intracellular fatty acid concentrations via endocytosis of the supplemented substrate. Furthermore, fatty-acid endocytosis alleviated substrate cytotoxicity in E. coli. These traits attributed to bacterial endocytosis resulted in dramatically elevated biotransformation efficiencies in fed-batch and cell-recycle reaction systems when caveolae-forming E. coli was used for the bioconversion of ricinoleic acid (12-hydroxyoctadec-9-enoic acid) to ( Z)-11-(heptanoyloxy) undec-9-enoic acid. We propose that CAV1-mediated endocytosing E. coli represents a versatile tool for the biotransformation of hydrophobic substrates.

Activation of the Glutamic Acid-Dependent Acid Resistance System in Escherichia coli BL21(DE3) Leads to Increase of the Fatty Acid Biotransformation Activity

The biosynthesis of carboxylic acids including fatty acids from biomass is central in envisaged biorefinery concepts. The productivities are often, however, low due to product toxicity that hamper whole-cell biocatalyst performance. Here, we have investigated factors that influence the tolerance of Escherichia coli to medium chain carboxylic acid (i.e., n-heptanoic acid)-induced stress. The metabolic and genomic responses of E. coli BL21(DE3) and MG1655 grown in the presence of n-heptanoic acid indicated that the GadA/B-based glutamic acid-dependent acid resistance (GDAR) system might be critical for cellular tolerance. The GDAR system, which is responsible for scavenging intracellular protons by catalyzing decarboxylation of glutamic acid, was inactive in E. coli BL21(DE3). Activation of the GDAR system in this strain by overexpressing the rcsB and dsrA genes, of which the gene products are involved in the activation of GadE and RpoS, respectively, resulted in acid tolerance not only to HCl but also to n-heptanoic acid. Furthermore, activation of the GDAR system allowed the recombinant E. coli BL21(DE3) expressing the alcohol dehydrogenase of Micrococcus luteus and the Baeyer-Villiger monooxygenase of Pseudomonas putida to reach 60% greater product concentration in the biotransformation of ricinoleic acid (i.e., 12-hydroxyoctadec-9-enoic acid (1)) into n-heptanoic acid (5) and 11-hydroxyundec-9-enoic acid (4). This study may contribute to engineering E. coli-based biocatalysts for the production of carboxylic acids from renewable biomass.

High temperature stimulates acetic acid accumulation and enhances the growth inhibition and ethanol production by Saccharomyces cerevisiae under fermenting conditions

Cellular responses of Saccharomyces cerevisiae to high temperatures of up to 42 °C during ethanol fermentation at a high glucose concentration (i.e., 100 g/L) were investigated. Increased temperature correlated with stimulated glucose uptake to produce not only the thermal protectant glycerol but also ethanol and acetic acid. Carbon flux into the tricarboxylic acid (TCA) cycle correlated positively with cultivation temperature. These results indicate that the increased demand for energy (in the form of ATP), most likely caused by multiple stressors, including heat, acetic acid, and ethanol, was matched by both the fermentation and respiration pathways. Notably, acetic acid production was substantially stimulated compared to that of other metabolites during growth at increased temperature. The acetic acid produced in addition to ethanol seemed to subsequently result in adverse effects, leading to increased production of reactive oxygen species. This, in turn, appeared to cause the specific growth rate, and glucose uptake rate reduced leading to a decrease of the specific ethanol production rate far before glucose depletion. These results suggest that adverse effects from heat, acetic acid, ethanol, and oxidative stressors are synergistic, resulting in a decrease of the specific growth rate and ethanol production rate and, hence, are major determinants of cell stability and ethanol fermentation performance of S. cerevisiae at high temperatures. The results are discussed in the context of possible applications.

Ethanol reduces mitochondrial membrane integrity and thereby impacts carbon metabolism of Saccharomyces cerevisiae

Saccharomyces cerevisiae is an excellent ethanol producer, but is rather sensitive to high concentration of ethanol. Here, influences of ethanol on cellular membrane integrity and carbon metabolism of S. cerevisiae were investigated to rationalize mechanism involved in ethanol toxicity. Addition of 5% (v/v) ethanol did neither significantly change the permeability of the cytoplasmic membrane of the reference strain S. cerevisiae BY4741 nor of the ethanol-tolerant strain iETS3. However, the addition of ethanol resulted in a marked decrease in the mitochondrial membrane potential and in increased concentrations of intracellular reactive oxygen species (ROS). The carbon flux was redistributed under these conditions from mainly ethanol production to the TCA cycle. This redistribution was possibly a result of increased energy demand for cell maintenance that increased from about zero to 20-40 mmol ATP (g(CDW)  h)(-1) . This increase in maintenance energy might be explained by the ethanol-induced reduction of the proton motive force and the required removal of ROS. Thus, the stability of the mitochondrial membrane and subsequently the capacity to keep ROS levels low could be important factors to improve tolerance of S. cerevisiae against ethanol.

APOBEC3H haplotypes and HIV-1 pro-viral vif DNA sequence diversity in early untreated human immunodeficiency virus-1 infection

We examined single nucleotide polymorphisms (SNP) in the APOBEC3 locus on chromosome 22, paired with population sequences of pro-viral human immunodeficiency virus-1 (HIV-1) vif from peripheral blood mononuclear cells, from 96 recently HIV-1-infected treatment-naive adults. We found evidence for the existence of an APOBEC3H linkage disequilibrium (LD) block associated with variation in GA → AA, or APOBEC3F/H signature, sequence changes in pro-viral HIV-1 vif sequence (top 10 significant SNPs with a significant p = 4.8 × 10(-3)). We identified a common five position risk haplotype distal to APOBEC3H (A3Hrh). These markers were in high LD (D' = 1; r(2) = 0.98) to a previously described A3H "RED" haplotype containing a variant (E121) with enhanced susceptibility to HIV-1 Vif. This association was confirmed by a haplotype analysis. Homozygote carriers of the A3Hrh had lower GA->AA (A3F/H) sequence editing upon pro-viral HIV-1 vif sequence (p = 0.01), and lower HIV-1 RNA levels over time during early, untreated HIV-1 infection, (p = 0.015 mixed effects model). This effect may be due to enhanced susceptibility of A3H forms to HIV-1 Vif mediated viral suppression of sequence editing activity, slowing viral diversification and escape from immune responses.

Recurrent unilateral frosted branch angiitis

In the left eye of a 27-year-old man we found perivascular creamy sheathing of retinal veins with retinal hemorrhages and, on fluorescein angiography, delayed filling of veins with late leakage. Dramatic recovery of visual acuity and healing of retinal lesions followed intravenous corticosteroid therapy. However, the condition recurred several times within a few months. Fluorescein angiography showed delayed filling of arteries and veins and arteriovenous anastomoses with a widespread capillary nonperfusion area. Eventually, neovascular glaucoma resulted. It is suggested that frosted branch angiitis is related to vascular occlusion. Systemic corticosteroid therapy seems to affect the course of this disease.

Intravitreal cysticercosis

Examination of a 36-year-old man with naked visual acuity of 20/20 revealed a floating, conspicuous cyst of Cysticercus cellulosae in the vitreous cavity of the right eye. A vitreous traction band from the vitreous base and the optic disc was connected to the lodging bulb of the cyst. In the superonasal area, an ovoid retinal break surrounded by a white retinal lesion with two elliptical retinal hemorrhages was found, and this seems to be the previous lodging site of the cyst. A pars plana vitrectomy was performed to remove the parasite, and laser photocoagulation was carried out around the retinal break. Four months after the operation, the patient was satisfied with naked visual acuity of 25/20 without any complication in the affected eye.

Partner notification and the control of human immunodeficiency virus infection. Two years of experience in San Francisco

To evaluate partner notification of opposite-sex sexual partners of AIDS patients as a means of limiting sexual and vertical transmission of human immunodeficiency virus (HIV), the authors examined the first 27 months of their experience with partner notification. Overall, of 145 AIDS patients eligible to participate, 51 (35%) were interviewed and identified 135 opposite-sex sexual partners. Of the 135 partners, 59 (44%) were interviewed and 34 (25%) were tested, resulting in the diagnosis of 7 (5%) HIV-infected partners. Refusal rates for index patients and partners were low (9% and 12%, respectively). Costs for the program were $454 per partner interviewed and $2,203 per seropositive partners identified. The authors conclude that although partner notification is more expensive than more widely targeted AIDS prevention and education efforts, its ability to target case finding, education, and counseling to women at highest risk of infection makes it potentially cost-effective for prevention of vertically transmitted HIV infection.

The epidemiology of AIDS in Asian and Pacific Islander populations in San Francisco

To evaluate the epidemiology of HIV infection in Asian and Pacific Islander populations in San Francisco, we compared cases of AIDS reported in Asians and Pacific Islanders with those reported in other racial and ethnic groups. The incidence of AIDS in Asians and Pacific Islanders was significantly lower than in Whites, Blacks, Latinos and American Indians and Alaska natives. AIDS cases among Asians and Pacific Islanders have increased 177% since 1985 compared with 54% in other racial and ethnic groups, with the greatest increase in homosexual and bisexual men and transfusion recipients. Among Asian and Pacific Islander ethnic groups, the incidence of AIDS was 168 cases per 100,000 in Polynesians, 141 per 100,000 in Japanese, 92 per 100,000 in 100 Filipinos, 72 per 100,000 in southeast Asians, and 21 per 100,000 in Chinese. We conclude that AIDS cases are disproportionately increasing in Asians and Pacific Islanders in San Francisco.