Direct Measurements of Collisional Dynamics in Cold Atom Triads.

The introduction of optical tweezers for trapping atoms has opened remarkable opportunities for manipulating few-body systems. Here, we present the first bottom-up assembly of atom triads. We directly observe atom loss through inelastic collisions at the single event level, overcoming the substantial challenge in many-atom experiments of distinguishing one-, two-, and three-particle processes. We measure a strong suppression of three-body loss, which is not fully explained by the presently availably theory for three-body processes. The suppression of losses could indicate the presence of local anticorrelations due to the interplay of attractive short range interactions and low dimensional confinement. Our methodology opens a promising pathway in experimental few-body dynamics.

Asymptomatic Intestinal Colonization with Protist Blastocystis Is Strongly Associated with Distinct Microbiome Ecological Patterns.

Blastocystis is the most prevalent protist of the human intestine, colonizing approximately 20% of the North American population and up to 100% in some nonindustrialized settings. Blastocystis is associated with gastrointestinal and systemic disease but can also be an asymptomatic colonizer in large populations. While recent findings in humans have shown bacterial microbiota changes associated with this protist, it is unknown whether these occur due to the presence of Blastocystis or as a result of inflammation. To explore this, we evaluated the fecal bacterial and eukaryotic microbiota in 156 asymptomatic adult subjects from a rural population in Xoxocotla, Mexico. Colonization with Blastocystis was strongly associated with an increase in bacterial alpha diversity and broad changes in beta diversity and with more discrete changes to the microbial eukaryome. More than 230 operational taxonomic units (OTUs), including those of dominant species Prevotella copri and Ruminococcus bromii, were differentially abundant in Blastocystis-colonized individuals. Large functional changes accompanied these observations, with differential abundances of 202 (out of 266) predicted metabolic pathways (PICRUSt), as well as lower fecal concentrations of acetate, butyrate, and propionate in colonized individuals. Fecal calprotectin was markedly decreased in association with Blastocystis colonization, suggesting that this ecological shift induces subclinical immune consequences to the asymptomatic host. This work is the first to show a direct association between the presence of Blastocystis and shifts in the gut bacterial and eukaryotic microbiome in the absence of gastrointestinal disease or inflammation. These results prompt further investigation of the role Blastocystis and other eukaryotes play within the human microbiome. IMPORTANCE Given the results of our study and other reports of the effects of the most common human gut protist on the diversity and composition of the bacterial microbiome, Blastocystis and, possibly, other gut protists should be studied as ecosystem engineers that drive community diversity and composition.

Microbiome-driven allergic lung inflammation is ameliorated by short-chain fatty acids.

The mammalian gastrointestinal tract harbors a microbial community with metabolic activity critical for host health, including metabolites that can modulate effector functions of immune cells. Mice treated with vancomycin have an altered microbiome and metabolite profile, exhibit exacerbated T helper type 2 cell (Th2) responses, and are more susceptible to allergic lung inflammation. Here we show that dietary supplementation with short-chain fatty acids (SCFAs) ameliorates this enhanced asthma susceptibility by modulating the activity of T cells and dendritic cells (DCs). Dysbiotic mice treated with SCFAs have fewer interleukin-4 (IL4)-producing CD4+ T cells and decreased levels of circulating immunoglobulin E (IgE). In addition, DCs exposed to SCFAs activate T cells less robustly, are less motile in response to CCL19 in vitro, and exhibit a dampened ability to transport inhaled allergens to lung draining nodes. Our data thus demonstrate that gut dysbiosis can exacerbate allergic lung inflammation through both T cell- and DC-dependent mechanisms that are inhibited by SCFAs.

Low-level regulatory T-cell activity is essential for functional type-2 effector immunity to expel gastrointestinal helminths.

Helminth infection is frequently associated with the expansion of regulatory T cells (Tregs) and suppression of immune responses to bystander antigens. We show that infection of mice with the chronic gastrointestinal helminth Heligmosomoides polygyrus drives rapid polyclonal expansion of Foxp3(+)Helios(+)CD4(+) thymic (t)Tregs in the lamina propria and mesenteric lymph nodes while Foxp3(+)Helios(-)CD4(+) peripheral (p)Treg expand more slowly. Notably, in partially resistant BALB/c mice parasite survival positively correlates with Foxp3(+)Helios(+)CD4(+) tTreg numbers. Boosting of Foxp3(+)Helios(+)CD4(+) tTreg populations by administration of recombinant interleukin-2 (rIL-2):anti-IL-2 (IL-2C) complex increased worm persistence by diminishing type-2 responsiveness in vivo, including suppression of alternatively activated macrophage and granulomatous responses at the sites of infection. IL-2C also increased innate lymphoid cell (ILC) numbers, indicating that Treg functions dominate over ILC effects in this setting. Surprisingly, complete removal of Tregs in transgenic Foxp3-DTR mice also resulted in increased worm burdens, with "immunological chaos" evident in high levels of the pro-inflammatory cytokines IL-6 and interferon-γ. In contrast, worm clearance could be induced by anti-CD25 antibody-mediated partial depletion of early Treg, alongside increased T helper type 2 responses and without incurring pathology. These findings highlight the overarching importance of the early Treg response to infection and the non-linear association between inflammation and the prevailing Treg frequency.

The DNA-binding domain of the gene regulatory protein AreA extends beyond the minimal zinc-finger region conserved between GATA proteins.

The AreA protein of Aspergillus nidulans regulates the activity of over 100 genes involved in the utilisation of nitrogen, and has a limited region of homology with the vertebrate family of GATA proteins around a zinc finger (Zf) motif. A 66 amino acid (a.a.) residue fragment (Zf(66)) corresponding to the zinc finger, a 91 a.a fragment (Zf(91)) containing an additional 25 a.a. at the C-terminus, and a much larger 728 a.a. sequence (3'EX) corresponding to the 3'exon have been over-expressed as fusion proteins in E. coli and purified. The DNA-protein complexes formed by these proteins have been examined by gel retardation analysis. The 91 a.a. protein forms a discrete shifted species with a GATA-containing DNA fragment with high affinity (K(d)=0.15 nM), whereas the 66 a.a. protein has very low ( approximately microM) affinity for the same sequence. The results show that the region of AreA required for high affinity DNA binding extends beyond the zinc finger motif that is homologous to GATA-1, requiring in addition a region within the 25 a.a. sequence C-terminal to the zinc finger. Using hydroxyl radical and ethylation interference footprinting, the minimal Zinc finger protein (Zf(66)) shows no appreciable interference effects whereas Zf(91) shows much stronger interference effects, identical to those of the larger protein. These effects extend over sequences up to two nucleotides either side of the GATA site, and indicate contacts additional to those observed in the three-dimensional structure of the complex of the minimal zinc-finger protein with DNA. We suggest that these additional contacts are responsible for the enhanced DNA binding affinity of the extended zinc-finger protein Zf(91).

A pilot HIV prevention program for adolescents in a psychiatric hospital.

In a pilot HIV prevention program for 35 adolescents in a psychiatric hospital, patients completed assessments of their HIV-related knowledge, attitudes, and behaviors before entering the program, at discharge, and three months after discharge. At discharge they showed significant increases in knowledge, tolerance of people with AIDS, and self-efficacy (or perceived ability to engage in safe-sex behaviors), although those who had been sexually abused showed significantly less change in self-efficacy than others. At three-month follow-up, scores had returned to baseline, but there was a trend toward increased condom use. Findings confirm the need for HIV-AIDS interventions for adolescents in psychiatric settings despite barriers to implementation.

DNA binding and subunit interactions in the type I methyltransferase M.EcoR124I.

The type I DNA methyltransferase M.EcoR124I consists of two methylation subunits (HsdM) and one DNA recognition subunit (HsdS). When expressed independently, HsdS is insoluble, but this subunit can be obtained in soluble form as a GST fusion protein. We show that the HsdS subunit, even as a fusion protein, is unable to form a discrete complex with its DNA recognition sequence. When HsdM is added to the HsdS fusion protein, discrete complexes are formed but these are unable to methylate DNA. The two complexes formed correspond to species with one or two copies of the HsdM subunit, indicating that blocking the N-terminus of HsdS affects one of the HsdM binding sites. However, removal of the GST moiety from such complexes results in tight and specific DNA binding and restores full methylation activity. The results clearly demonstrate the importance of the HsdM subunit for DNA binding, in addition to its catalytic role in the methyltransferase reaction.

Basic ocular pharmacotherapy.

1. There are certain unique features of pharmacotherapy as it relates to the eye. One is that we have the ability to apply a drug directly to the surface of the eye in the form of eyedrops. This has important ramifications in terms of pharmacokinetics, the distribution of drug throughout the ocular tissues. 2. Ocular pharmacokinetics is the study of the distribution of a drug over time. One of the principles of pharmacotherapy is that we want to maximize the amount of drug that reaches the site of action in a sufficient concentration to cause a beneficial therapeutic effect. 3. Ophthalmic nurses play an important role in patient education, because they spend time talking to patients about the proper way to use drugs.

Adolescent coping behavior when confronted with a friend with AIDS.

The coping strategies employed by adolescents (n = 871) when presented with a hypothetical situation of a friend with AIDS were examined. Adolescents reported a wide range of imagined responses that were generally adaptive. Girls more than boys and distressed students more than nondistressed students were likely to endorse adaptive coping items. Comparison of the students with a separate sample (n = 472) that responded to a hypothetical situation of a suicidal peer revealed more distress in girls for the AIDS problem and more distress in boys for the suicide problem, contrary to expectations. Adolescents were more distressed and endorsed a wider variety of coping strategies in response to the AIDS scenario than to the suicide problem. Implications for care of adolescents dealing with these significant issues are discussed.

HIV prevention for adolescents: utility of the Health Belief Model.

The Health Belief Model (HBM) has been applied to diverse sets of health behaviors. Research that suggests difficulties of the HBM in predicting future behaviors, especially HIV-related, is reviewed. Prominent features of adolescence that influence HIV-related risk behaviors are discussed including: cognitive immaturity, struggle for psychological autonomy, peer influences, and physical development. It is suggested that a model is needed to guide prevention efforts, and that these adolescent-specific factors need to be incorporated into any such model.

Assessing daily diabetes management by 24-hour recall interview: the validity of children's reports.

The current investigation examined the accuracy of diabetic children's 24-hr recall data by comparing the 7- to 12-year-old children's reports to direct observations of their behavior. Observers' data evidenced sufficient reliability to serve as an acceptable standard to which the children's 24-hr recall data could be compared. The children exhibited excellent agreement with the observers' data on all measures of the occurrence/nonoccurrence of events, including insulin injections, exercise periods, glucose tests, meal, type and amount of insulin injected. Although somewhat poorer reporters on some behaviors, differences were small. Children underreported most dietary behaviors and some exercise behaviors.