The formin mDia2 stabilizes microtubules independently of its actin nucleation activity

A critical microtubule (MT) polarization event in cell migration is the Rho/mDia-dependent stabilization of a subset of MTs oriented toward the direction of migration. Although mDia nucleates actin filaments, it is unclear whether this or a separate activity of mDia underlies MT stabilization. We generated two actin mutants (K853A and I704A) in a constitutively active version of mDia2 containing formin homology domains 1 and 2 (FH1FH2) and found that they still induced stable MTs and bound to the MT TIP proteins EB1 and APC, which have also been implicated in MT stabilization. A dimerization-impaired mutant of mDia2 (W630A) also generated stable MTs in cells. We examined whether FH1FH2mDia2 had direct activity on MTs in vitro and found that it bound directly to MTs, stabilized MTs against cold- and dilution-induced disassembly, and reduced the rates of growth and shortening during MT assembly and disassembly, respectively. These results indicate that mDia2 has a novel MT stabilization activity that is separate from its actin nucleation activity.     

The normalization of gene expression data in melanoma: investigating the use of glyceraldehyde 3-phosphate dehydrogenase and 18S ribosomal RNA as internal reference genes for quantitative real-time PCR

We examined a panel of 26 melanoma and fibroblast samples (tissues and cultured cells) to evaluate the suitability of two commonly used housekeeping genes, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and 18S ribosomal RNA (rRNA), for quantitative real-time PCR. Both genes showed significant variations within the individual cell line and tissue groups. Although no overall trends were observed in the expression of the 18S rRNA, GAPDH was up-regulated in melanoma tissue and cultured cells compared with the corresponding normal samples. In melanoma and fibroblast cell lines and tissues, absolute quantification appears to be more appropriate than normalizing messenger RNA (mRNA) expression via GAPDH or 18S rRNA housekeeping genes.     

Fast and efficient alkaline peroxide treatment to enhance the enzymatic digestibility of steam-exploded softwood substrates.

The enzymatic digestibility of steam-exploded Douglas-fir wood chips (steam exploded at 195 degrees C, 4.5 min, and 4.5% (w/w) SO(2)) was significantly improved using an optimized alkaline peroxide treatment. Best hydrolysis yields were attained when the steam-exploded material was post-treated with 1% hydrogen peroxide at pH 11.5 and 80 degrees C for 45 min. This alkaline peroxide treatment was applied directly to the water-washed, steam-exploded material eliminating the need for independent alkali treatment with 0.4% NaOH, which has been traditionally used to post-treat wood samples to try to remove residual lignin. Approximately 90% of the lignin in the original wood was solubilized by this novel procedure, leaving a cellulose-rich residue that was completely hydrolyzed within 48 h, using an enzyme loading of 10 FPU/g cellulose. About 82% of the originally available polysaccharide components of the wood could be recovered. The 18% of the carbohydrate that was not recovered was lost primarily to sugar degradation during steam explosion.     

Distribution of class I, III and IV alcohol dehydrogenase mRNAs in the adult rat, mouse and human brain.

The localization of different classes of alcohol dehydrogenases (ADH) in the brain is of great interest because of their role in both ethanol and retinoic acid metabolism. Conflicting data have been reported in the literature. By Northern blot and enzyme activity analyses only class III ADH has been detected in adult brain specimens, while results from riboprobe in situ hybridization indicate class I as well as class IV ADH expression in different regions of the rat brain. Here we have studied the expression patterns of three ADH classes in adult rat, mouse and human tissues using radioactive oligonucleotide in situ hybridization. Specificity of probes was tested on liver and stomach control tissue, as well as tissue from class IV ADH knock-out mice. Only class III ADH mRNA was found to be expressed in brain tissue of all three investigated species. Particularly high expression levels were found in neurons of the red nucleus in human tissue, while cortical neurons, pyramidal and granule cells of the hippocampus and dopamine neurons of substantia nigra showed moderate expression levels. Purkinje cells of cerebellum were positive for class III ADH mRNA in all species investigated, whereas granular layer neurons were positive only in rodents. The choroid plexus was highly positive for class III ADH, while no specific signal for class I or class IV ADH was detected. Our results thus support the notion that the only ADH expressed in adult mouse, rat and human brain is class III ADH.     

Net carbon flux from agriculture: Carbon emissions, carbon sequestration, crop yield, and land-use change

There is a potential to sequester carbon in soil by changing agricultural management practices. These changes in agricultural management can also result in changes in fossil-fuel use, agricultural inputs, and the carbon emissions associated with fossil fuels and other inputs. Management practices that alter crop yields and land productivity can affect the amount of land used for crop production with further significant implications for both emissions and sequestration potential. Data from a 20-year agricultural experiment were used to analyze carbon sequestration, carbon emissions, crop yield, and land-use change and to estimate the impact that carbon sequestration strategies might have on the net flux of carbon to the atmosphere. Results indicate that if changes in management result in decreased crop yields, the net carbon flux can be greater under the new system, assuming that crop demand remains the same and additional lands are brought into production. Conversely, if increasing crop yields lead to land abandonment, the overall carbon savings from changes in management will be greater than when soil carbon sequestration alone is considered.     

Export from Pericentriolar Endocytic Recycling Compartment to Cell Surface Depends on Stable, Detyrosinated (Glu) Microtubules and Kinesin

A significant fraction of internalized transferrin (Tf) concentrates in the endocytic recycling compartment (ERC), which is near the microtubule-organizing center in many cell types. Tf then recycles back to the cell surface. The mechanisms controlling the localization, morphology, and function of the ERC are not fully understood. We examined the relationship of Tf trafficking with microtubules (MTs), specifically the subset of stable, detyrosinated Glu MTs. We found some correlation between the level of stable Glu MTs and the distribution of the ERC; in cells with low levels of Glu MTs concentrated near to the centriole, the ERC was often tightly clustered, whereas in cells with higher levels of Glu MTs throughout the cell, the ERC was more dispersed. The clustered ERC in Chinese hamster ovary cells became dispersed when the level of Glu MTs was increased with taxol treatment. Furthermore, in a temperature-sensitive Chinese hamster ovary cell line (B104-5), the cells had more Glu MTs when the ERC became dispersed at elevated temperature. Microinjecting purified anti-Glu tubulin antibody into B104-5 cells at elevated temperature induced the redistribution of the ERC to a tight cluster. Microinjection of anti-Glu tubulin antibody slowed recycling of Tf to the cell surface without affecting Tf internalization or delivery to the ERC. Similar inhibition of Tf recycling was caused by microinjecting anti-kinesin antibody. These results suggest that stable Glu MTs and kinesin play a role in the organization of the ERC and in facilitating movement of vesicles from the ERC to the cell surface.     

Eocene primates from Myanmar: Historical perspectives on the origin of Anthropoidea

The phylogenetic and geographic origins of the primate suborder Anthropoidea have long been major focal points in the study of primate evolution. Field work in Africa and Asia over the past forty years has produced a bewildering array of fossil primates, many having been linked in one way or another with the early origins of anthropoids. Asia recently has become fashionable in some circles as the ultimate geographic source of anthropoids, while Africa remains a viable alternative for others. In this paper we discuss the history of discovery of the Eocene primates of Myanmar and then offer our views on the current status of these Myanmar primates in the ongoing debate over anthropoid origins.     

Habitat use by fishes after tidal reconnection of an impounded estuarine wetland in the Indian River Lagoon,Florida (USA)

Most of the wetlands located along the Indian River Lagoon (IRL) ineast-central Florida (USA) have been impounded since the 1950's and1960's to reduce mosquito reproduction. Impounded marsh (i.e.,impoundment) dikes physically separate the wetlands from the estuary toallow artificial flooding of the impoundments during the mosquito breedingperiod (May to October). Presently, Rotational ImpoundmentManagement (RIM) is the preferred impoundment management techniquein the IRL. Impoundments maintained under RIM have culverts installedthrough the dikes which are kept closed during the mosquito breedingseason (to control mosquitos) and are allowed to remain open for theremainder of the year (to allow tidal flow). A 24.3 ha impoundment8 km north of Sebastian Inlet that had been isolated from the IRL for over39 years was studied for 12 months to determine habitat use by fishes aftertidal reconnection and the implementation of RIM. Fish sampling wasconducted with a seine in the perimeter ditch and with clover and minnowtraps in the upper marsh and tidal creek areas of the impoundment. Waterlevel, impoundment bottom topography, and the seasonal nursery functionof the impoundment were factors that contributed to observed patterns offish habitat use during the study. Within the first 15 weeks of perimeterditch sampling, an increase from 9 to 40 species was observed. Transientspecies used the perimeter ditch almost exclusively and entered theimpoundment primarily during the spring open period. Juvenile Pogonias cromis (Linnaeus), Elops saurus Linnaeus, Centropomusundecimalis (Bloch), and Megalops atlanticus Valenciennes were themost abundant recreationally important species, respectively. Habitat useby the most abundant resident species (Gambusia holbrooki Girard,Poecilia latipinna (Lesueur), Cyprinodon variegatus Lacepède, andFundulus confluentus Goode & Bean) was influenced primarily bywater level fluctuations. Resident species used the upper marsh and tidalcreek habitats during summer flooded periods and the cyprinodontids leftthe interior surface of the impoundment last as water levels decreased. Thisstudy is the first to document the recovery of fish populations in areconnected impoundment north of Sebastian Inlet using both active andpassive sampling techniques.     

Invasive species in China — an overview

China is a vast country with rich biodiversity, which makes China especially vulnerable to invasive species. It has a long history of introduction of non-native species, especially those with perceived beneficial impacts. Its rapid economic development, including an explosive growth in international trade and transportation, has increased the potential for new introductions. Currently, alien species are widespread in the country, occur in many ecosystems, represent most major taxonomic groups, and are introduced unintentionally as well as intentionally for cultivation. The paper lists various cases of invasive species which have caused significant threats or damages to local natural or artificial ecosystems, and indicates that two example industries (fresh water fisheries and lawn grasses) have brought or tend to bring in many invasive species and hence have caused or will cause changes and loss of biodiversity in local ecosystems. Based on these studies, it is suggested that China combat the problem through enhancing awareness, development of a database on invasive species, strengthening international co-operation, preparing case studies and introducing the necessary legislation, regulations and monitoring.