Aneuploidy and isolation in two Hypochoeris species

The annual species Hypochoeris glabra (2n = 10) and the perennial H. radicata (2n = 8) hybridise readily in nature and in experiment. During meiosis in F₁ hybrids the maximum association is a chain of seven and a bivalent indicating that at least three interchanges differentiate the two genomes. The nucleolar chromosomes in the two species are homologous and form a ring bivalent. They are, however, differentiated since in the F₁ hybrid only one nucleolar-organiser region is expressed. Although chromosomal differentiation reduces the egg fertility of F₁ hybrids to about 1%, viable backcross hybrids to H. radicata as pollen parent have been experimentally produced and occur in natural populations. Backcrosses with 8, 9 and rarely 13 chromosomes are found and those with 2n = 8 are fully interfertile with H. radicata. Gene flow may therefore take place in natural populations across an aneuploid barrier. The direction of gene flow in Hypochoeris is probably unidirectional from the annual to the perennial.     

Interaction of Four Soybean Cultivars with Subsoiling and a Nematicide

Yields of four soybean, Glycine max, cultivars were increased with subsoiling under the row and application of the nematicide, DBCP i 1,2-dibromo-3-chloropropane) in Tiflon sandy loam heavily infested with the root-knot nematode Meloidogyne incognita. These cultivars represent four maturity groups: very early (V), "Essex'', early (VI), "Davis'': medium (VII), ''Ransom''; and late (VIII), '' Hutton ''. The average increase for the four cullivars was about the same for subsoiling or DBCP. When the treatmcnts were used together, the increase was greater than when either was used alone, but the effects were not additive. Increased yields were obtained with subsoiling and DBCP for the most nematode resistant cultivar, Hutton, as well as for the most susccptiblc, Davis. Subsoiling reduced root-knot galling in nonfumigated plots but did not affect it in fumigated plots. On 12 September, M. incognita larvae were most numerous at the 0- to 20 cm depth, intermediate at 20 to 33 cm depth and least numerous at 33 to 46 cm depth, Subsoiling did not affect larval populations at the three levels.     

Fluctuating asymmetry of morphometric characters in house mice: the effects of age, sex, and phenotypical extremeness in a randombred population

Fluctuating asymmetry (FA) was calculated for nine paired morphometric characters in a randombred population of house mice in order to assess the effects of age, sex, and phenotypical extremeness. FA did not significantly vary between sexes for any of the characters, and age proved to be significant only for innominate length. Additionally, FA values in high extreme individuals and low extreme individuals were compared to those for intermediate individuals to discover whether extreme individuals showed increased fluctuating asymmetry (decreased developmental stability) due to increased levels of homozygosity. Differences in fluctuating asymmetry magnitudes were found between the groups, although the extreme individuals did not consistently show increased fluctuating asymmetry and FA differences also showed no significant association with the level of heritability of each character. Potential reasons for these findings are discussed.     

Targeting NADPH Oxidase and Phospholipases A2 in Alzheimer’s Disease

Alzheimer’s disease (AD) is marked by an increase in the production of extracellular beta amyloid plaques and intracellular neurofibrillary tangles associated with a decline in brain function. Increases in oxidative stress are regarded as an early sign of AD pathophysiology, although the source of reactive oxygen species (ROS) and the mechanism(s) whereby beta amyloid peptides (Aβ) impact oxidative stress have not been adequately investigated. Recent studies provide strong evidence for the involvement of NADPH oxidase and its downstream oxidative signaling pathways in the toxic effects elicited by Aβ. ROS produced by NADPH oxidase activate multiple signaling pathways leading to neuronal excitotoxicity and glial cell-mediated inflammation. This review describes recent studies demonstrating the neurotoxic effects of Aβ in conjunction with ROS produced by NADPH oxidase and the downstream pathways leading to activation of cytosolic phospholipase A₂ (PLA₂) and secretory PLA₂. In addition, this review also describes recent studies using botanical antioxidants to protect against oxidative damage associated with AD. Investigating the metabolic and signaling pathways involving Aβ NADPH oxidase and PLA₂ can help understand the mechanisms underlying the neurodegenerative effects of oxidative stress in AD. This information should provide new therapeutic approaches for prevention of this debilitating disease.     

Proteomic identification of the cerebral cavernous malformation signaling complex

Cerebral cavernous malformations (CCM) are sporadic or inherited vascular lesions of the central nervous system characterized by dilated, thin-walled, leaky vessels. Linkage studies have mapped autosomal dominant mutations to three loci: ccm1 (KRIT1), ccm2 (OSM), and ccm3 (PDCD10). All three proteins appear to be scaffolds or adaptor proteins, as no enzymatic function can be attributed to them. Our previous results demonstrated that OSM is a scaffold for the assembly of the GTPase Rac and the MAPK kinase kinase MEKK3, for the hyperosmotic stress-dependent activation of p38 MAPK. Herein, we show that the three CCM proteins are members of a larger signaling complex. To define this complex, epitope-tagged wild type OSM or OSM harboring the mutation of F217-->A, which renders the OSM phosphotyrosine binding (PTB) domain unable to bind KRIT1, were stably introduced into RAW264.7 mouse macrophages. FLAG-OSM or FLAG-OSMF217A and the associated complex members were purified by immunoprecipitation using anti-FLAG antibody. OSM binding partners were identified by gel-based methods combined with electrospray ionization-MS or by multidimensional protein identification technology (MudPIT). Previously identified proteins that associate with OSM including KRIT1, MEKK3, Rac, and the KRIT1-binding protein ICAP-1 were found in the immunoprecipitates. In addition, we show for the first time that PDCD10 binds to OSM and is found in cellular CCM complexes. Other prominent proteins that bound the CCM complex include EF1A1, RIN2, and tubulin, with each interaction disrupted with the OSMF217A mutant protein. We further show that PDCD10 binds phosphatidylinositol di- and triphosphates and OSM binds phosphatidylinositol monophosphates. The findings define the targeting of the CCM complex to membranes and to proteins regulating trafficking and the cytoskeleton.     

Achieving Molecular Selectivity in Imaging Using Multiphoton Raman Spectroscopy Techniques

In the case of most optical imaging methods, contrast is generated either by physical properties of the sample (Differential Image Contrast, Phase Contrast), or by fluorescent labels that are localized to a particular protein or organelle. Standard Raman and infrared methods for obtaining images are based upon the intrinsic vibrational properties of molecules, and thus obviate the need for attached fluorophores. Unfortunately, they have significant limitations for live-cell imaging. However, an active Raman method, called Coherent Anti-Stokes Raman Scattering (CARS), is well suited for microscopy, and provides a new means for imaging specific molecules. Vibrational imaging techniques, such as CARS, avoid problems associated with photobleaching and photo-induced toxicity often associated with the use of fluorescent labels with live cells. Because the laser configuration needed to implement CARS technology is similar to that used in other multiphoton microscopy methods, such as two-photon fluorescence and harmonic generation, it is possible to combine imaging modalities, thus generating simultaneous CARS and fluorescence images. A particularly powerful aspect of CARS microscopy is its ability to selectively image deuterated compounds, thus allowing the visualization of molecules, such as lipids, that are chemically indistinguishable from the native species.