LEAP2 changes with body mass and food intake in humans and mice

Acyl-ghrelin administration increases food intake, body weight, and blood glucose. In contrast, mice lacking ghrelin or ghrelin receptors (GHSRs) exhibit life-threatening hypoglycemia during starvation-like conditions but do not consistently exhibit overt metabolic phenotypes when given ad libitum food access. These results, and findings of ghrelin resistance in obese states, imply nutritional state-dependence of ghrelin’s metabolic actions. Here, we hypothesized that LEAP2 (liver enriched antimicrobial peptide-2), a recently-characterized endogenous GHSR antagonist, blunts ghrelin action during obese states and post-prandially. To test this hypothesis, we determined changes in plasma LEAP2 and acyl-ghrelin due to fasting, eating, obesity, Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), oral glucose administration, and type 1 diabetes mellitus (T1DM) using humans and/or mice. Our results suggest that plasma LEAP2 is regulated by metabolic status: its levels increase with body mass and blood glucose, and decrease with fasting, RYGB, and in post-prandial states following VSG. These changes were mostly opposite to those of acyl-ghrelin. Furthermore, using electrophysiology, we showed that LEAP2 both hyperpolarizes and prevents acyl-ghrelin from activating arcuate NPY neurons. We predict that the plasma LEAP2:acyl-ghrelin molar ratio may be a key determinant modulating acyl-ghrelin activity in response to body mass, feeding status, and blood glucose

Dust Devil Tracks

Dust devils that leave dark- or light-toned tracks are common on Mars and they can also be found on the Earth’s surface. Dust devil tracks (hereinafter DDTs) are ephemeral surface features with mostly sub-annual lifetimes. Regarding their size, DDT widths can range between ∼1 m and ∼1 km, depending on the diameter of dust devil that created the track, and DDT lengths range from a few tens of meters to several kilometers, limited by the duration and horizontal ground speed of dust devils. DDTs can be classified into three main types based on their morphology and albedo in contrast to their surroundings; all are found on both planets: (a) dark continuous DDTs, (b) dark cycloidal DDTs, and (c) bright DDTs. Dark continuous DDTs are the most common type on Mars. They are characterized by their relatively homogenous and continuous low albedo surface tracks. Based on terrestrial and martian in situ studies, these DDTs most likely form when surficial dust layers are removed to expose larger-grained substrate material (coarse sands of ≥500 μm in diameter). The exposure of larger-grained materials changes the photometric properties of the surface; hence leading to lower albedo tracks because grain size is photometrically inversely proportional to the surface reflectance. However, although not observed so far, compositional differences (i.e., color differences) might also lead to albedo contrasts when dust is removed to expose substrate materials with mineralogical differences. For dark continuous DDTs, albedo drop measurements are around 2.5 % in the wavelength range of 550–850 nm on Mars and around 0.5 % in the wavelength range from 300–1100 nm on Earth. The removal of an equivalent layer thickness around 1 μm is sufficient for the formation of visible dark continuous DDTs on Mars and Earth. The next type of DDTs, dark cycloidal DDTs, are characterized by their low albedo pattern of overlapping scallops. Terrestrial in situ studies imply that they are formed when sand-sized material that is eroded from the outer vortex area of a dust devil is redeposited in annular patterns in the central vortex region. This type of DDT can also be found in on Mars in orbital image data, and although in situ studies are lacking, terrestrial analog studies, laboratory work, and numerical modeling suggest they have the same formation mechanism as those on Earth. Finally, bright DDTs are characterized by their continuous track pattern and high albedo compared to their undisturbed surroundings. They are found on both planets, but to date they have only been analyzed in situ on Earth. Here, the destruction of aggregates of dust, silt and sand by dust devils leads to smooth surfaces in contrast to the undisturbed rough surfaces surrounding the track. The resulting change in photometric properties occurs because the smoother surfaces have a higher reflectance compared to the surrounding rough surface, leading to bright DDTs. On Mars, the destruction of surficial dust-aggregates may also lead to bright DDTs. However, higher reflective surfaces may be produced by other formation mechanisms, such as dust compaction by passing dust devils, as this may also cause changes in photometric properties. On Mars, DDTs in general are found at all elevations and on a global scale, except on the permanent polar caps. DDT maximum areal densities occur during spring and summer in both hemispheres produced by an increase in dust devil activity caused by maximum insolation. Regionally, dust devil densities vary spatially likely controlled by changes in dust cover thicknesses and substrate materials. This variability makes it difficult to infer dust devil activity from DDT frequencies. Furthermore, only a fraction of dust devils leave tracks. However, DDTs can be used as proxies for dust devil lifetimes and wind directions and speeds, and they can also be used to predict lander or rover solar panel clearing events. Overall, the high DDT frequency in many areas on Mars leads to drastic albedo changes that affect large-scale weather patterns

Applications of electrified dust and dust devil electrodynamics to Martian atmospheric electricity

Atmospheric transport and suspension of dust frequently brings electrification, which may be substantial. Electric fields of 10 kVm-1 to 100 kVm-1 have been observed at the surface beneath suspended dust in the terrestrial atmosphere, and some electrification has been observed to persist in dust at levels to 5 km, as well as in volcanic plumes. The interaction between individual particles which causes the electrification is incompletely understood, and multiple processes are thought to be acting. A variation in particle charge with particle size, and the effect of gravitational separation explains to, some extent, the charge structures observed in terrestrial dust storms. More extensive flow-based modelling demonstrates that bulk electric fields in excess of 10 kV m-1 can be obtained rapidly (in less than 10 s) from rotating dust systems (dust devils) and that terrestrial breakdown fields can be obtained. Modelled profiles of electrical conductivity in the Martian atmosphere suggest the possibility of dust electrification, and dust devils have been suggested as a mechanism of charge separation able to maintain current flow between one region of the atmosphere and another, through a global circuit. Fundamental new understanding of Martian atmospheric electricity will result from the ExoMars mission, which carries the DREAMS (Dust characterization, Risk Assessment, and Environment Analyser on the Martian Surface)-MicroARES (Atmospheric Radiation and Electricity Sensor) instrumentation to Mars in 2016 for the first in situ measurements

Isolation And Characterization Of Y Chromosome Dna Probes

A sorted, cloned Y chromosome phage library was screened for unique Y chromosome sequences. Of the thousands of plaques screened, 13 did not hybridize to radiolabeled 46, XX total chromosomal DNA. Three plaques were characterized further. Clone Y1 hybridized to multiple restriction enzyme fragments in both male and female DNA with more intense bands in male DNA. Clone Y2, also found in female and male DNA, is probably located in the pseudosutosomal region because extra copies of either the X or Y chromosomes increased Y2 restriction enzyme fragment intensity in total cellular DNA. Clone Y5 was male specific in three of four restriction enzyme digests althouth in the fourth a light hybridizing band was observed in both male and female DNA. Clone Y5 was sublocalized to band Yq 11.22 by hybridization to a panel of cellular DNA from patients with Y chromosome rearrangements. Clone Y5 can be used to test for retention of the proximally long arm Y suggested to cause gonadal cancer in carrier females. The long series of GA repeats in Y5, anticipated to be polymorphic, may provide a sensitive means to follow Y chromosome variation in human populations. © 1992.1891581589Schonberg, (1989) Handbook of Human Growth and Developmental Biology, 2, pp. 229-237. , 2nd Edition, E. Meisami, P. Timivas, CRC Press, Boca Raton, FLPage, de la Chapelle, Weissenbach, (1985) Nature, 315, pp. 224-226Disteche, Casanova, Saal, Friedman, Sybert, Graham, Thuline, Page, (1986) PNAS, 83, pp. 7841-7844Vergnaud, Page, Simmler, Brown, Rouyer, Noel, Botstein, Weissenbach, (1986) Am. J. Hum. Genet, 38, pp. 109-124McLaren, Simpson, Tomonari, Chandler, Hogg, (1984) Nature, 312, pp. 552-555Simpson, Chandler, Goulmy, Disteche, Ferguson-Smith, Page, (1987) Nature, 326, pp. 876-878Koopman, Gubbay, Vivian, Goodfellow, Lovell-Badge, (1991) Nature, 351, pp. 117-121Washburn, Eicher, (1983) Nature, 303, pp. 338-34015Rouyer, Simmler, Johnsson, Vergnaud, Cooke, Weissenbach, (1986) Nature, 319, pp. 291-295Yen, Marsh, Allen, Taai, Ellison, Connolly, Neiswanger, Shapiro, (1988) Cell, 55, pp. 1123-1138de la Chapelle, The etiology of maleness in XX men (1981) Human Genetics, 58, pp. 105-116Page, Mosher, Simpson, Fisher, Mardon, Pollack, McGillivray, Brown, The sex-determining region of the human Y chromosome encodes a finger protein (1987) Cell, 51, pp. 1091-1104Lau, (1984) The Y Chromosome, Part A: Basic Characteristics of the Y Chromosome, pp. 177-192. , A. Sandberg, Alan R. Liss, New YorkNgo, Vergnaud, Johnsson, Lucotte, Weissenbach, (1986) Am. J. Hum. Genet, 38, pp. 407-418Wolman, David, Koo, (1985) The Y chromosome. Part A: basic characteristics of the Y chromosome, pp. 477-505. , A. Sandberg, Alan R. Liss, NYGemmill, Pearce-Birge, Bixenman, Hecht, Allanson, (1987) Am. J. Hum. Genet, 41, pp. 157-167Goosens, Kan, [49] DNA analysis in the diagnosis of hemoglobin disorders (1981) Method. Enzymol, 76, pp. 805-817Van Dilla, Deaven, Construction of gene libraries for each human chromosome (1990) Cytometry, 11, pp. 208-218Sambrook, Fritsch, Maniatis, (1989) Molecular Cloning: a Laboratory Manual, , 2nd Edition, Cold Spring Harbor Press, NYRigby, Dieckmann, Rhodes, Berg, (1977) J. Mol. Biol, 113, pp. 237-251Feinberg, Vogelstein, (1984) Anal. Biochem, 137, pp. 266-267Farah, Garmes, Cavalcanti, Mello, Porelli, Ramos, Sartorato, (1991) Brazilian J. Med. Biol. Res, 24, pp. 149-156Southern, (1975) J. Mol. Biol, 98, pp. 503-51

Ex vivo and in vitro primary mast cells.

Mast cells are cells of the innate immune system whose biological responses are markedly modulated by effector molecules of adaptive immunity, i.e., antibodies. They thus contribute to anti-infectious defense but also to antibody-dependent inflammatory responses. They are especially well known as inducers of allergic reactions. They are widely distributed in most tissues, but in low numbers. They are not readily purified, and with a poor yield. For these reasons, means to generate large numbers of homogenous non-transformed mast cells have been developed. We describe here (1) fractionation methods suitable for purifying mouse or rat peritoneal mast cells and for purifying human mast cells of various origins, and (2) conditions for generating pure cultured mast cell populations from mouse, rat, and human tissues