Interpopulation Variation in Contour Feather Structure Is Environmentally Determined in Great Tits

Background: The plumage of birds is important for flying, insulation and social communication. Contour feathers cover most of the avian body and among other functions they provide a critical insulation layer against heat loss. Feather structure and composition are known to vary among individuals, which in turn determines variation in the insulation properties of the feather. However, the extent and the proximate mechanisms underlying this variation remain unexplored. Methodology/Principal Findings: We analyzed contour feather structure from two different great tit populations adapted to different winter regimes, one northern population in Oulu (Finland) and one southern population in Lund (Sweden). Great tits from the two populations differed significantly in feather structure. Birds from the northern population had a denser plumage but consisting of shorter feathers with a smaller proportion containing plumulaceous barbs, compared with conspecifics from the southern population. However, differences disappeared when birds originating from the two populations were raised and moulted in identical conditions in a common-garden experiment located in Oulu, under ad libitum nutritional conditions. All birds raised in the aviaries, including adult foster parents moulting in the same captive conditions, developed a similar feather structure. These feathers were different from that of wild birds in Oulu but similar to wild birds in Lund, the latter moulting in more benign conditions than those of Oulu. Conclusions/Significance: Wild populations exposed to different conditions develop contour feather differences either due to plastic responses or constraints. Environmental conditions, such as nutrient availability during feather growth play a crucial role in determining such differences in plumage structure among populations

Retromer and Its Role in Regulating Signaling at Endosomes.

The retromer complex is a key element of the endosomal protein sorting machinery being involved in trafficking of proteins from endosomes to the Golgi and also endosomes to the cell surface. There is now accumulating evidence that retromer also has a prominent role in regulating the activity of many diverse signaling proteins that traffic through endosomes and this activity has profound implications for the functioning of many different cell and tissue types from neuronal cells to cells of the immune system to specialized polarized epithelial cells of the retina. In this review, the protein composition of the retromer complex will be described along with many of the accessory factors that facilitate retromer-mediated endosomal protein sorting to detail how retromer activity contributes to the regulation of several distinct signaling pathways

The Peripheral Binding of 14-3-3γ to Membranes Involves Isoform-Specific Histidine Residues

Mammalian 14-3-3 protein scaffolds include seven conserved isoforms that bind numerous phosphorylated protein partners and regulate many cellular processes. Some 14-3-3-isoforms, notably γ, have elevated affinity for membranes, which might contribute to modulate the subcellular localization of the partners and substantiate the importance of investigating molecular mechanisms of membrane interaction. By applying surface plasmon resonance we here show that the binding to phospholipid bilayers is stimulated when 14-3-3γ is complexed with its partner, a peptide corresponding to the Ser19-phosphorylated N-terminal region of tyrosine hydroxylase. Moreover, membrane interaction is dependent on salts of kosmotropic ions, which also stabilize 14-3-3γ. Electrostatic analysis of available crystal structures of γ and of the non-membrane-binding ζ-isoform, complemented with molecular dynamics simulations, indicate that the electrostatic potential distribution of phosphopeptide-bound 14-3-3γ is optimal for interaction with the membrane through amphipathic helices at the N-terminal dimerization region. In addition, His158, and especially His195, both specific to 14-3-3γ and located at the convex lateral side, appeared to be pivotal for the ligand induced membrane interaction, as corroborated by site-directed mutagenesis. The participation of these histidine residues might be associated to their increased protonation upon membrane binding. Overall, these results reveal membrane-targeting motifs and give insights on mechanisms that furnish the 14-3-3γ scaffold with the capacity for tuned shuffling from soluble to membrane-bound states.This work was supported by grants from the Norwegian Cancer Society (to ØH), Junta de Andalucía, grant CVI-02483 (to JMSR), The Research Council of Norway (grant 185181 to A.M.), the Western Norway Health Authorities (grant 911618 to A.M.) and The Kristian Gerhard Jebsen Foundation (to AM)

SNX3 controls Wingless/Wnt secretion through regulating retromer-dependent recycling of Wntless

Drosophila Wingless (Wg) acts as a morphogen during development. Wg secretion is controlled by a seven-pass transmembrane cargo Wntless (Wls). We have recently identified retromer as a key regulator involved in Wls trafficking. As sorting nexin (SNX) molecules are essential components of the retromer complex, we hypothesized that specific SNX(s) is required for retromer-mediated Wnt secretion. Here, we generated Drosophila mutants for all of the eight snx members, and identified Drosophila SNX3 (DSNX3) as an essential molecule required for Wg secretion. We show that Wg secretion and its signaling activity are defective in Dsnx3 mutant clones in wing discs. Wg levels in the culture medium of Dsnx3-depleted S2 cells are also markedly reduced. Importantly, Wls levels are strikingly reduced in Dsnx3 mutant cells, and overexpression of Wls can rescue the Wg secretion defect observed in Dsnx3 mutant cells. Moreover, DSNX3 can interact with the retromer component Vps35, and co-localize with Vps35 in early endosomes. These data indicate that DSNX3 regulates Wg secretion via retromer-dependent Wls recycling. In contrast, we found that Wg secretion is not defective in cells mutant for Drosophila snx1 and snx6, two components of the classical retromer complex. Ectopic expression of DSNX1 or DSNX6 fails to rescue the Wg secretion defect in Dsnx3 mutant wing discs and in Dsnx3 dsRNA-treated S2 cells. These data demonstrate the specificity of the DSNX3-retromer complex in Wls recycling. Together, our findings suggest that DSNX3 acts as a cargo-specific component of retromer, which is required for endocytic recycling of Wls and Wg/Wnt secretion

Limited implementation of California’s Healthy Default Beverage law for children’s meals sold online

ObjectiveTo reduce children's sugar-sweetened beverage intake, California's Healthy-By-Default Beverage law (SB1192) mandates only unflavoured dairy/non-dairy milk or water be the default drinks with restaurant children's meals. The objective of this study is to examine consistency with this law for meals sold through online platforms from restaurants in low-income California neighbourhoods.DesignThis observational, cross-sectional study examines beverage availability, upcharges (additional cost) and presentation of beverage options consistent with SB1192 (using four increasingly restrictive criteria) within a random sample of quick-service restaurants (QSR) in Supplemental Nutrition Assistance Program Education eligible census tracts selling children's meals online from November 2020 to April 2021.SettingLow-income California neighbourhoods (n 226 census tracts).ParticipantsQSR that sold children's meals online via a restaurant-specific platform, DoorDash, GrubHub and/or UberEats (n 631 observations from 254 QSR).ResultsSeventy percent of observations offered water; 63 % offered unflavoured milk. Among all beverages, water was most likely to have an upcharge; among observations offering water (n 445), 41 % had an upcharge (average $0·51). Among observations offering unflavoured milk (n 396), 11$0·38). No observations upcharged for soda (regular or diet). Implementation consistency with SB1192 ranged from 40·5 % (using the least restrictive criteria) to 5·6 % (most restrictive) of observations.ConclusionsBased on observations from restaurant websites and three of the most popular online ordering platforms, most California QSR located in low-income neighbourhoods are not offering children's meal beverages consistent with the state's Healthy-By-Default Beverage law. As the popularity of online ordering increases, further work to ensure restaurants offering healthy default beverages with children's meals sold online is necessary

Feasibility and Response to the San Diego County, California, Supplemental Nutrition Assistance Program (SNAP) Agency Sending Food and Nutrition Text Messages to All Participants: Quasi-Experimental Web-Based Survey Pilot Study

BackgroundThe Supplemental Nutrition Assistance Program (SNAP) provides over 40 million Americans with money for food without typically providing participants with food or nutrition information. Educational SMS text messages can reach large numbers of people, and studies suggest SNAP participants appreciate nutrition education and have access to mobile phones. ObjectiveUsing a pre-post intervention design, we assessed the feasibility of, and program satisfaction and outcomes resulting from, the San Diego County, California SNAP agency sending monthly food and nutrition education SMS text messages to all SNAP participants to increase fruit and vegetable purchasing and consumption. MethodsWe developed and sent 5 behavioral science–informed SMS text messages with links to a project website in English and Spanish with information about selecting, storing, and preparing seasonal fruits and vegetables. The San Diego County SNAP agency sent monthly texts to ~170,000 SNAP households from October 2020 to February 2021. SNAP participants completed web-based surveys in response to a text invitation from the SNAP agency in September 2020 (baseline, n=12,036) and April 2021 (follow-up, n=4927). Descriptive frequencies were generated, and adjusted multiple linear mixed models were run on a matched data set of participants that completed both baseline and follow-up surveys (n=875) assessing pre- or postattitudes, behaviors, knowledge, and self-efficacy. We used adjusted logistic regression models to assess differences between the matched (n=875) and nonmatched (n=4052) participants related to experiences with the intervention (questions asked only at follow-up). ResultsAfter the intervention, matched participants reported significant increase in knowing where to get information about selecting, storing, and preparing fruits and vegetables (3.76 vs 4.02 on a 5-point Likert scale with 5=strongly agree, P<.001); feeling good about participating in SNAP (4.35 vs 4.43, P=.03); and thinking the CalFresh program helps them eat healthy (4.38 vs 4.48, P=.006). No significant pre- or postdifferences were found in fruit or vegetable consumption, though most participants at follow-up (n=1556, 64%) reported their consumption had increased. Among the sample that completed the follow-up survey only (n=4052, not including 875 participants who completed follow-up and baseline), 1583 (65%) and 1556 (64%) reported purchasing and eating more California-grown fruits and vegetables, respectively. Nearly all respondents appreciated the intervention (n=2203, 90%) and wanted it to continue (n=2037, 83%). ConclusionsSNAP can feasibly provide food and nutrition messages via text to participants. A monthly text campaign was well received by responding participants and improved some measures of their self-reported knowledge, self-efficacy, produce consumption, and perceptions of SNAP participation. Participants expressed interest in continuing to receive texts. While educational messages will not solve the complex food and nutrition challenges confronting SNAP participants, further work should employ rigorous methods to expand and test this intervention in other SNAP programs before considering to implement it at scale

Corticosterone mediated costs of reproduction link current to future breeding

Life-history theory predicts that costs are associated with reproduction. One possible mediator of costs involves the secretion of glucocorticoid hormones, which in birds can be measured in feathers grown during the breeding period. Glucocorticoids mediate physiological responses to unpredictable environmental or other stressors, but they can also function as metabolic regulators during more predictable events such as reproduction. Here we show that corticosterone (“Cort”) in feathers grown during the breeding season reflects reproductive effort in two Antarctic seabird species (giant petrels, Macronectes spp.). In females of both species, but not males, feather Cort (“fCort”) was nearly 1.5 fold higher in successful than failed breeders (those that lost their eggs/chicks), suggesting a cost of successful reproduction, i.e. high fCort levels in females reflect the elevated plasma Cort levels required to support high metabolic demands of chick-rearing. Successful breeding also led to delayed moult prior to winter migration. The fCort levels and pre-migration moult score that we measured at the end of current breeding were predictive of subsequent reproductive effort in the following year. Birds with high fCort and a delayed initiation of moult were much more likely to defer breeding in the following year. Cort levels and the timing of moult thus provide a potential mechanism for the tradeoff between current and future reproduction