Accumulation of autophagic vacuoles and cardiomyopathy in LAMP-2-deficient mice

Lysosome-associated membrane protein-2 (LAMP-2) is a highly glycosylated protein and an important constituent of the lysosomal membrane. Here we show that LAMP-2 deficiency in mice increases mortality between 20 and 40 days of age. The surviving mice are fertile and have an almost normal life span. Ultrastructurally, there is extensive accumulation of autophagic vacuoles in many tissues including liver, pancreas, spleen, kidney and skeletal and heart muscle. In hepatocytes, the autophagic degradation of long-lived proteins is severely impaired. Cardiac myocytes are ultrastructurally abnormal and heart contractility is severely reduced. These findings indicate that LAMP-2 is critical for autophagy. This theory is further substantiated by the finding that human LAMP-2 deficiency causing Danon's disease is associated with the accumulation of autophagic material in striated myocytes.     

Fractal morphology, imaging and mass spectrometry of single aerosol particles in flight

The morphology of micrometre-size particulate matter is of critical importance in fields ranging from toxicology to climate science, yet these properties are surprisingly difficult to measure in the particles' native environment. Electron microscopy requires collection of particles on a substrate; visible light scattering provides insufficient resolution; and X-ray synchrotron studies have been limited to ensembles of particles. Here we demonstrate an in situ method for imaging individual sub-micrometre particles to nanometre resolution in their native environment, using intense, coherent X-ray pulses from the Linac Coherent Light Source free-electron laser. We introduced individual aerosol particles into the pulsed X-ray beam, which is sufficiently intense that diffraction from individual particles can be measured for morphological analysis. At the same time, ion fragments ejected from the beam were analysed using mass spectrometry, to determine the composition of single aerosol particles. Our results show the extent of internal dilation symmetry of individual soot particles subject to non-equilibrium aggregation, and the surprisingly large variability in their fractal dimensions. More broadly, our methods can be extended to resolve both static and dynamic morphology of general ensembles of disordered particles. Such general morphology has implications in topics such as solvent accessibilities in proteins, vibrational energy transfer by the hydrodynamic interaction of amino acids, and large-scale production of nanoscale structures by flame synthesis.     

Radioactive 26Al from massive stars in the Galaxy

Gamma-rays from radioactive 26Al (half-life approximately 7.2 x 10(5) years) provide a 'snapshot' view of continuing nucleosynthesis in the Galaxy. The Galaxy is relatively transparent to such gamma-rays, and emission has been found concentrated along its plane. This led to the conclusion that massive stars throughout the Galaxy dominate the production of 26Al. On the other hand, meteoritic data show evidence for locally produced 26Al, perhaps from spallation reactions in the protosolar disk. Furthermore, prominent gamma-ray emission from the Cygnus region suggests that a substantial fraction of Galactic 26Al could originate in localized star-forming regions. Here we report high spectral resolution measurements of 26Al emission at 1808.65 keV, which demonstrate that the 26Al source regions corotate with the Galaxy, supporting its Galaxy-wide origin. We determine a present-day equilibrium mass of 2.8 (+/- 0.8) solar masses of 26Al. We use this to determine that the frequency of core collapse (that is, type Ib/c and type II) supernovae is 1.9 (+/- 1.1) events per century.     

Lymphoid cells of the intestinal mucosa with double kappa and lambda specificity in normal man]

The presence of lymphoid cells possessing both kappa and lambda specificities has been observed in the intestinal mucosa of normal subjects. The variability in the number of such cells in different sections of the same sample and in different subjects seems to be a characteristic of this cell population and may reflect the high activity of the immune system in the small intestine.     

Gene structure of the murine 2'-5'-oligoadenylate synthetase family

The 2'-5'-oligoadenylate synthetases (OASs) are members of a family of interferon-induced proteins playing an important role in the antiviral effect of interferons as well as being involved in apoptosis and control of cellular growth. Based on sequence data from the murine BAC clone (RP23-39M18), and a number of EST and IMAGE clones and the Celera Mouse database, we identified twelve Oas genes in the mouse genome, all localized to the chromosome 5F region. In contrast to the single OAS1 gene found in humans, we identified eight closely linked Oas1 genes in the murine genome, together with the genes of Oas2 and Oas3. Compared to the single OASL gene found in humans, two genes of OAS-like proteins, Oasl1 and Oasl2, were identified. All the putative genes seem to be transcribed. The exon/intron structures of the murine Oas genes were found to be identical to those of the human genes.     

Complementation cloning identifies CDG-IIc, a new type of congenital disorders of glycosylation, as a GDP-fucose transporter deficiency

Congenital disorders of glycosylation (CDG) comprise a rapidly growing group of inherited disorders in which glycosylation of glycoproteins is defective due to mutations in genes required for the assembly of lipid-linked oligosaccharides, their transfer to nascent glycoproteins (CDG-I) or the processing of protein-bound glycans (CDG-II). Previously' a defect in the GDP-fucose import into the lumen of the Golgi was identified in a person with CDG (A.C.) with a general deficiency of fucosyl residues in glycoproteins. This patient presents the clinical features of leukocyte adhesion deficiency type II (LAD II) including mental retardation, short stature, facial stigmata, and recurrent bacterial peripheral infections with persistently elevated peripheral leukocytes. Using a fucose-specific, lectin-staining procedure for detection of fucosylated glycoproteins and a retroviral cDNA library, we isolated a cDNA complementing the fucosylation defect in the patient's fibroblasts. The cDNA encodes a highly hydrophobic protein of 364 amino acids with multiple putative transmembrane domains. Restoration of GDP-fucose import activity in Golgi-enriched vesicles from the patient's fibroblasts verified the GDP-fucose transporter activity of this protein. We identified two missense mutations in the GDP-fucose transporter cDNA of patient A.C. and of two other people with LAD II. Thus complementation cloning allowed us to identify the human GDP-fucose transporter cDNA and GDP-fucose transporter deficiency as a cause for a new type of CDG. Following the recent recommendations for the nomenclature for CDG, this new type is classified as CDG-IIc (formerly LAD II).