A Highlights from MBoC Selection: Lipid domain–dependent regulation of single-cell wound repair

After damage, cells reseal their plasma membrane and repair the underlying cortical cytoskeleton. Although many different proteins have been implicated in cell repair, the potential role of specific lipids has not been explored. Here we report that cell damage elicits rapid formation of spatially organized lipid domains around the damage site, with different lipids concentrated in different domains as a result of both de novo synthesis and transport. One of these lipids—diacylglycerol (DAG)—rapidly accumulates in a broad domain that overlaps the zones of active Rho and Cdc42, GTPases that regulate repair of the cortical cytoskeleton. Formation of the DAG domain is required for Cdc42 and Rho activation and healing. Two DAG targets, protein kinase C (PKC) β and η, are recruited to cell wounds and play mutually antagonistic roles in the healing process: PKCβ participates in Rho and Cdc42 activation, whereas PKCη inhibits Rho and Cdc42 activation. The results reveal an unexpected diversity in subcellular lipid domains and the importance of such domains for a basic cellular process.     

The marine algae of the Hebridean Island of Colonsay

Four specimens attributable to the freshwater red algal taxon, Ptilothamnion richardsii, were examined from locations in Australia and French Guiana, and partial rbcL gene sequence data were obtained. Phylogenetic analyses showed these specimens to be allied to taxa in the Batrachospermales. The two specimens from Australia were determined to be Batrachospermum antipodites, differing from that taxon by only 15?bp (1.2%). The two specimens from French Guiana were within the Batrachospermum section Contorta clade, but differed considerably (≥8%) from the taxa for which there are presently rbcL gene data. The sequence data clearly show these specimens to be chantransia stages of Batrachospermum taxa. Recently, other described freshwater Audouinella taxa have also been shown to be chantransia stages. Like previous authors, we argue that it is useful to continue to recognize entities with particular morphological characters and propose the form taxa Chantransia richardsii, C. macrospora and C. pygmaea. A key to these is provided.     

A role for cyclic-GMP dependent protein kinase in anoikis

Anoikis is an essential process in which a loss of adhesion to the substratum alters intracellular signaling pathways that lead to apoptosis. Using phosphorylation of vasodilator stimulated phosphoprotein (VASP) as an indicator of cGMP-dependent protein kinase (PKG) activity in vivo, it was found that suspension of the colon epithelial cell line (CCD841) leads to rapid and transient activation of PKG that lasted several hours. The colon carcinoma lines SW480 and SW620 do not express endogenous PKG, but exogenously expressed PKG was similarly activated upon cell suspension. To determine whether PKG has a role in apoptosis following cell suspension, poly-ADP ribose polymerase (PARP) cleavage and propidium iodide staining were measured. After 24 h in suspension it was found that approximately 50% of CCD841 cells exhibited apoptosis, whereas apoptosis was not detected in either of the colon carcinoma cell lines. Inhibition of type 1 PKG by expression of a dominant negative PKG construct (G1alphaR-GFP), or by incubation with the PKG inhibitor peptide DT-2, blocked apoptosis in suspended CCD841 cells by approximately 50%. Furthermore, expression of exogenous PKG in SW620 and SW480 cells conferred partial sensitivity anoikis. Taken together these findings indicate that PKG has an important role in the induction of apoptosis following suspension of normal colon epithelial cells, and loss of PKG expression in colon tumor cells may contribute to resistance to anoikis.     

The association of television and video viewing with fast food intake by preschool-age children

Objective: To examine the extent to which television (TV) and video viewing is associated with consumption of fast food by preschool‐age children. Research Methods and Procedures: In a cross‐sectional study of 240 parents of children ages 2.0 to 5.9 years, parents reported the number of hours their child watched TV/videos on an average weekday and weekend day in the past month; a daily, weighted average of TV/video viewing was then calculated. The main outcome was parents’ report of their children's fast food intake, using the question, “How many times a week does your child eat at fast food restaurants such as McDonald's, Burger King, or Kentucky Fried Chicken?” dichotomized to (never/<1 vs. ≥1 time/wk). The association of TV/video viewing with fast food intake was evaluated by multiple logistic regression before and after adjusting for several potential confounders. Results: Twenty‐two percent of parents reported that their child ate at fast food restaurants at least once per week. After adjusting for parents’ age, race/ethnicity, and household income as well as child's age and sex, for each 1‐hour increase of TV/video watched per day, the odds ratio (OR) for consuming fast food ≥1 time per week was 1.60 (95% confidence interval, 1.03 to 2.49). After further adjustment for socio‐environmental factors that might serve as proxies for the availability of healthy food options, such as parental time constraints and the availability and high cost of fresh fruits and vegetables in their neighborhoods, the OR for consuming fast food ≥1 time per week was minimally attenuated (OR, 1.55; 95% confidence interval, 1.04 to 2.31). Discussion: TV/video viewing was correlated with fast food consumption among preschool children in this study. Our findings raise the possibility that greater exposure to TV and videos may influence preschool children's consumption of unhealthful foods.     

Prenylated benzoic acid derivatives from Piper aduncum L. and P. hostmannianum C. DC. (Piperaceae)

The bioactivity-guided fractionation of the crude extracts from leaves of Brazilian species Piper aduncum and Piper hostmannianum by means of bioautography using the fungi Cladosporium cladosporioides and C. sphaerospermum afforded prenylated methyl benzoate, chromenes, and dihydrobenzopyran derivatives as antifungal compounds. The isolation and structural elucidation of a new compound methyl 4-hydroxy-3-(2′-hydroperoxy-3′-methyl-3′-butenyl)benzoate were performed by application of chromatographic techniques and spectroscopic analyses.     

Architecture of the SARS coronavirus prefusion spike

The emergence in 2003 of a new coronavirus (CoV) responsible for the atypical pneumonia termed severe acute respiratory syndrome (SARS) was a stark reminder that hitherto unknown viruses have the potential to cross species barriers to become new human pathogens. Here we describe the SARS-CoV 'spike' structure determined by single-particle cryo-EM, along with the docked atomic structures of the receptor-binding domain and prefusion core.     

Pet owners' views of pet behavior problems and willingness to consult experts for assistance

Prior research has found that dog obedience training and the receipt of advice regarding companion animal (pet) behavior reduce the risk of nonhuman animal relinquishment to an animal shelter and increase human-companion animal interactions, but research also finds that only a minority of pet guardians participates in such activities. The researchers for this study asked 170 dog and cat guardians to assess the seriousness of common problem behaviors and how likely they were to seek help. The researchers also asked them to rate different methods of obtaining expert advice. The dog and cat guardians saw behaviors directly affecting humans as most severe; those involving the destruction of property were next in severity; and those affecting the animal more than the human were least severe. There were no significant differences in ratings by participants' gender or income. Participants indicated they were more likely to use free help options than fee-based services. The lack of a clear correlation between the seriousness of a behavior problem and likelihood of seeking help suggests that other factors may play a role in pet guardians' interest in obtaining expert advice.