Genome sequence and comparative analysis of the model rodent malaria parasite Plasmodium yoelii yoelii

Species of malaria parasite that infect rodents have long been used as models for malaria disease research. Here we report the whole-genome shotgun sequence of one species, Plasmodium yoelii yoelii, and comparative studies with the genome of the human malaria parasite Plasmodium falciparum clone 3D7. A synteny map of 2,212 P. y. yoelii contiguous DNA sequences (contigs) aligned to 14 P. falciparum chromosomes reveals marked conservation of gene synteny within the body of each chromosome. Of about 5,300 P. falciparum genes, more than 3,300 P. y. yoelii orthologues of predominantly metabolic function were identified. Over 800 copies of a variant antigen gene located in subtelomeric regions were found. This is the first genome sequence of a model eukaryotic parasite, and it provides insight into the use of such systems in the modelling of Plasmodium biology and disease.     

A physical map of the mouse genome

A physical map of a genome is an essential guide for navigation, allowing the location of any gene or other landmark in the chromosomal DNA. We have constructed a physical map of the mouse genome that contains 296 contigs of overlapping bacterial clones and 16,992 unique markers. The mouse contigs were aligned to the human genome sequence on the basis of 51,486 homology matches, thus enabling use of the conserved synteny (correspondence between chromosome blocks) of the two genomes to accelerate construction of the mouse map. The map provides a framework for assembly of whole-genome shotgun sequence data, and a tile path of clones for generation of the reference sequence. Definition of the human-mouse alignment at this level of resolution enables identification of a mouse clone that corresponds to almost any position in the human genome. The human sequence may be used to facilitate construction of other mammalian genome maps using the same strategy.     

Targeted mutation of Cyln2 in the Williams syndrome critical region links CLIP-115 haploinsufficiency to neurodevelopmental abnormalities in mice

Williams syndrome is a neurodevelopmental disorder caused by the hemizygous deletion of 1.6 Mb on human chromosome 7q11.23. This region comprises the gene CYLN2, encoding CLIP-115, a microtubule-binding protein of 115 kD. Using a gene-targeting approach, we provide evidence that mice with haploinsufficiency for Cyln2 have features reminiscent of Williams syndrome, including mild growth deficiency, brain abnormalities, hippocampal dysfunction and particular deficits in motor coordination. Absence of CLIP-115 also leads to increased levels of CLIP-170 (a closely related cytoplasmic linker protein) and dynactin at the tips of growing microtubules. This protein redistribution may affect dynein motor regulation and, together with the loss of CLIP-115-specific functions, underlie neurological alterations in Williams syndrome.     

Ultrafast and direct imprint of nanostructures in silicon

The fabrication of micrometre- and nanometre-scale devices in silicon typically involves lithography and etching. These processes are costly and tend to be either limited in their resolution or slow in their throughput. Recent work has demonstrated the possibility of patterning substrates on the nanometre scale by 'imprinting' or directed self-assembly, although an etching step is still required to generate the final structures. We have devised and here demonstrate a rapid technique for patterning nanostructures in silicon that does not require etching. In our technique which -- we call 'laser-assisted direct imprint' (LADI) -- a single excimer laser pulse melts a thin surface layer of silicon, and a mould is embossed into the resulting liquid layer. A variety of structures with resolution better than 10 nm have been imprinted into silicon using LADI, and the embossing time is less than 250 ns. The high resolution and speed of LADI, which we attribute to molten silicon's low viscosity (one-third that of water), could open up a variety of applications and be extended to other materials and processing techniques.     

Apoptosis disables CD31-mediated cell detachment from phagocytes promoting binding and engulfment

Macrophage recognition and ingestion of 'self' cells undergoing apoptosis in vivo protects tissues from the toxic contents of dying cells and modulates macrophage regulation of inflammatory and immune responses. However, the complex molecular mechanisms mediating macrophage discrimination between viable and apoptotic cells are poorly understood. In particular, little is known of why viable nucleated cells are not engulfed by macrophages. To reveal active repulsion of viable cells and to seek specific capture or 'tethering' of apoptotic cells, we studied macrophage binding of viable and apoptotic leukocytes under conditions of flow. We found that homophilic ligation of CD31 (ref. 4) on viable leukocytes promoted their active, temperature-dependent detachment under low shear, whereas such CD31-mediated detachment was disabled in apoptotic leukocytes, promoting tight binding and macrophage ingestion of dying cells. Here we propose that CD31 (also known as platelet-endothelial cell adhesion molecule-1, PECAM-1) is an example of a cell-surface molecule that prevents phagocyte ingestion of closely apposed viable cells by transmitting 'detachment' signals, and which changes function on apoptosis, promoting tethering of dying cells to phagocytes.     

Distribution of the milliped genus Apheloria Chamberlin, 1921; summaries of peripheral localities and ones of A. virginiensis (Drury, 1770) west of the Mississippi River (Polydesmida: Xystodesmidae)

The milliped genus Apheloria occupies a broad area in Québec and Ontario, Canada, and the United States east of the Central Plains, lying generally north of the Gulf Coastal states. It is reported for the 1st time from New Jersey, District of Columbia, Illinois, and Kansas; and the 1st localities are recorded for Massachusetts, Connecticut, South Carolina, Georgia, Alabama, and Wisconsin. The projected distribution encompasses all or parts of the District of Columbia and 27 states, including Vermont and Delaware, where the genus has not been taken; New Hampshire and Mississippi lie outside the range. Chesapeake Bay and the Connecticut River form apparent eastern boundaries in Maryland–Virginia and New England, respectively; the Tennessee River does likewise on the south in northern Alabama. Aside from Arkansas, comparatively few records exist from the 6 projected states of occurrence west of the Mississippi River. Only 1 each is available from Iowa and Kansas, and there are no definite localities in Nebraska, where occurrence is postulated at Omaha, the type locality of Fontaria luminosa Kenyon, 1893. Confirmation with fresh material is necessary, but this name seems referrable to Apheloria and may be senior to either A. virginiensis iowa or A. v. reducta , both by Chamberlin, 1939, if 2 distinct races occur west of the Mississippi River.     

Food of cougars in the Cascade Range of Oregon

Animal and nonanimal items were identified in the digestive tracts of 61 cougars ( Felis concolor ) collected between 1978 and 1984 from the western slopes of the Cascade Range in Oregon. Forty - two (69%) of the cougars were taken by hunters in December and January, 18 (30%) were killed at other times of the year because of their proximity to livestock, and one animal was illegally killed in November. Black-tailed deer ( Odocoileus hemionus columbianus ) was the most common prey item, although domestic sheep ( Ovis airies ), porcupines ( Erethizon dorsatum ), and a variety of small mammals were also recorded. Masticated grass was the most common nonanimal item.      

Notes on mycophagy in four species of mice in the genus Peromyscus

We examined stomach contents of 426 Clethrionomys , 217 C. californicus from western Oregon and 209 C. gapperi from widely scattered areas across North America. Clethrionomys californicus consumed fungi of 28 genera. Clethrionomys gapperi from the Rocky Mountains westward consumed fungi of 23 genera, whereas C. gapperi east of the Rocky Mountains consumed fungi of 7 genera. This study supports the conclusions of an earlier study, limited to Oregon and Washington, that food habits of C. californicus and C. gapperi are more closely related to habitat than to species or subspecies of vole.