Enhanced CpG mutability and tumorigenesis in MBD4-deficient mice

The mammalian protein MBD4 contains a methyl-CpG binding domain and can enzymatically remove thymine (T) or uracil (U) from a mismatched CpG site in vitro. These properties suggest that MBD4 might function in vivo to minimize the mutability of 5-methylcytosine by removing its deamination product from DNA. We tested this hypothesis by analyzing Mbd4-/- mice and found that the frequency of of C --> T transitions at CpG sites was increased by a factor of three. On a cancer-susceptible Apc(Min/+) background, Mbd4-/- mice showed accelerated tumor formation with CpG --> TpG mutations in the Apc gene. Thus MBD4 suppresses CpG mutability and tumorigenesis in vivo.     

The atmosphere of Mars: detection of krypton and xenon

Krypton and xenon have been discovered in the martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.     

Simultaneous binding of PtdIns(4,5)P2 and clathrin by AP180 in the nucleation of clathrin lattices on membranes

Adaptor protein 180 (AP180) and its homolog, clathrin assembly lymphoid myeloid leukemia protein (CALM), are closely related proteins that play important roles in clathrin-mediated endocytosis. Here, we present the structure of the NH2-terminal domain of CALM bound to phosphatidylinositol-4,5- bisphosphate [PtdIns(4,5)P2] via a lysine-rich motif. This motif is found in other proteins predicted to have domains of similar structure (for example, Huntingtin interacting protein 1). The structure is in part similar to the epsin NH2-terminal (ENTH) domain, but epsin lacks the PtdIns(4,5)P2-binding site. Because AP180 could bind to PtdIns(4,5)P2 and clathrin simultaneously, it may serve to tether clathrin to the membrane. This was shown by using purified components and a budding assay on preformed lipid monolayers. In the presence of AP180, clathrin lattices formed on the monolayer. When AP2 was also present, coated pits were formed.     

Photoperiod effects on2n pollen production,response to anther culture,and net photosynthesis of a diplandrous clone ofsolanum phureja

Flow-cytometric analysis of pollen samples obtained fromSolanum phureja, clone PP5, grown under 10, 14, and 18 hour photoperiods at the Southeastern Plant Environment Laboratories of North Carolina State University yielded two populations of pollen based on size parameters. These populations corresponded to pollen separation based on propidium iodide staining of DNA. Anther culture response from plants grown under 14 and 18 hour photoperiods for 8, 10, 12, and 14 weeks was greatest from 8 week old plants grown under a 14 hour photoperiod. Net photosynthesis was significantly higher for plants grown under a 10 hour photoperiod than for plants grown under either a 14, or 18 hour photoperiod. A significant positive correlation was found between net photosynthesis and tuber yield. Results suggest that vegetative growth is increased under short photoperiods, floral development is favored under long photoperiods, and androgenesis is greatest from young plants grown under an intermediate photoperiod.     

A retrospective study of surgically treated cases of septic peritonitis in the cat (2000–2007)

O bjectives : To review aetiology, clinical signs and outcome of cats surgically treated for septic peritonitis (2000-2007).
M ethods : A retrospective study. Inclusion criteria were the identification of intracellular bacteria and degenerate neutrophils and/or a positive culture from abdominal fluid and exploratory coeliotomy. Aetiology, clinical signs, haematological and biochemical parameters, surgical treatment and outcome were recorded and analysed.
R esults : Twenty-six cats fulfilled the inclusion criteria. Abdominal pain was reported in 10 (38 per cent) and vomiting was reported in 11 (42 per cent) of the cats. The most common aetiology was trauma (31 per cent). The principal source of contamination was the gastrointestinal tract. Hyperlactataemia, hypoproteinaemia and hyperglycaemia were reported in 9, 13 and 14 of the 26 cases, respectively. Non-survivors had significantly higher blood lactate concentrations than survivors (P=0·02). Nineteen cats were managed with primary closure, two with closed suction drains and three with open peritoneal drainage. Twelve (46 per cent) cats survived to discharge.
C linical S ignificance : In cats, lethargy, depression and anorexia were more common clinical signs than abdominal pain. Lactate level at the time of diagnosis may be a useful prognostic indicator in cats. The proportion of cats that survived was lower than previously reported and owners should be given a guarded prognosis.     

Fatty acids of the lipids of cultured herring

The composition of fatty acids was determined in neutral lipids and phospholipids from cultured herring reared on a diet based on squid muscle. The phospholipids retained the fatty acid pattern characteristic of marine fish. In contrast, the fatty acids of neutral lipids tended to reflect the fatty acid spectrum in the diet, and were very different from the characteristic pattern of herring oils. It was concluded that the cultured herring had little ability to modify dietary fatty acids and that the enzymes of phospholipid metabolism possess considerable specificity for certain fatty acids.