Phosphoproteomic analysis identifies Grb10 as an mTORC1 substrate that negatively regulates insulin signaling

The evolutionarily conserved serine-threonine kinase mammalian target of rapamycin (mTOR) plays a critical role in regulating many pathophysiological processes. Functional characterization of the mTOR signaling pathways, however, has been hampered by the paucity of known substrates. We used large-scale quantitative phosphoproteomics experiments to define the signaling networks downstream of mTORC1 and mTORC2. Characterization of one mTORC1 substrate, the growth factor receptor-bound protein 10 (Grb10), showed that mTORC1-mediated phosphorylation stabilized Grb10, leading to feedback inhibition of the phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated, mitogen-activated protein kinase (ERK-MAPK) pathways. Grb10 expression is frequently down-regulated in various cancers, and loss of Grb10 and loss of the well-established tumor suppressor phosphatase PTEN appear to be mutually exclusive events, suggesting that Grb10 might be a tumor suppressor regulated by mTORC1.     

Methods to increase the starch content of potato tuber callus tissue

Summary Attempts were made to increase the starch content of callus tissue from tubers of cvs Lemhi Russet and Russet Burbank by varying growth regulator concentration, sugar source, sugar concentration, temperature and callus shape. Starch content was always higher in media containing no growth regulators. Callus spread over the media contained more starch than unbroken rectangular or cube-shaped callus. Sucrose was superior to glucose and fructose for starch formation. A sucrose concentration of 20 % produced more starch than lower concentrations. Callus growth decreased as the sucrose concentration increased. ‘Lemhi Russet’ callus incubated with 8 % sucrose at 20, 25 and 30 °C contained 1.2, 0.4 and 0.8 % starch respectively, which was much higher than in ‘Russet Burbank’ callus. With varying amounts of mannitol as an osmoticum in 8 % sucrose, the most starch was found in the medium containing 5 % mannitol. Research Paper 92B2 of the Idaho Agricultural Experiment Station     

Hypersensitive and enzyme responses in potato tuber tissue treated withVerticillium dahliae and arachidonic acid

Wound-healing tuber tissues from two potato cultivars, one resistant (cv. Reddale) and one susceptible (cv. Kennebec) to Verticillium wilt caused by the fungusVerticillium dahliae were treated with elicitor preparations of either an autoclaved mycelial extract of the fungus or with the fungal component arachidonic acid (AA). Wound-healing tissues were analyzed for hypersensitive cell browning (HCB) and alterations in lipoxygenase (LOX), polyphenoloxidase (PPO), and peroxidase (PER) activities, because all three enzymes are thought to be involved in the hypersensitive response and plant defense. Healing Reddale tissues that were treated with the elicitors exhibited a much more rapid and intense HCB than did the healing Kennebec tissues. By 96 h, Reddale tissues treated with either elicitor preparation appeared dark brown and necrotic. Treated Kennebec tissues appeared only slightly darker than the controls after 96 h. LOX, PPO and PER activities in treated Reddale tissues were significantly less than that found in the control after 48 h, and by 96 h PPO and PER activities were nearly zero. In contrast, LOX activity in AA-treated Kennebec disks was higher than in the control at 96 h, while the activities of PPO and PER had decreased to about 60% of the control at the same time period. Our results show that HCB is strongly correlated withV. dahliae and AA elicitor treatments in the resistant vs. the susceptible cultivar, while the overall role of the three enzymes in cell browning and death remain unclear.     

Imaging genome abnormalities in cancer research

Increasing attention is focusing on chromosomal and genome structure in cancer research due to the fact that genomic instability plays a principal role in cancer initiation, progression and response to chemotherapeutic agents. The integrity of the genome (including structural, behavioral and functional aspects) of normal and cancer cells can be monitored with direct visualization by using a variety of cutting edge molecular cytogenetic technologies that are now available in the field of cancer research. Examples are presented in this review by grouping these methodologies into four categories visualizing different yet closely related major levels of genome structures. An integrated discussion is also presented on several ongoing projects involving the illustration of mitotic and meiotic chromatin loops; the identification of defective mitotic figures (DMF), a new type of chromosomal aberration capable of monitoring condensation defects in cancer; the establishment of a method that uses Non-Clonal Chromosomal Aberrations (NCCAs) as an index to monitor genomic instability; and the characterization of apoptosis related chromosomal fragmentations caused by drug treatments.     

Surveillance and control of rabies in La Reunion,Mayotte, and Madagascar

Mayotte and La Reunion islands are currently free of animal rabies and surveillance is performed by the French Human and Veterinary Public Health Services. However, dog rabies is still enzootic in Madagascar with 4 to 10 confirmed human cases each year. The number of antirabies medical centres in Madagascar is still scarce to provide easy access to the local population for post-exposure rabies prophylaxis. Furthermore, stray dog populations are considerable and attempts to control rabies by mass campaigns of dog vaccination have not received sufficient attention from the national health authorities. To address these challenges, an expanded program to control rabies needs to be initiated by the Malagasy authorities.     

Clinical comparison of the Welch Allyn SureSight™ handheld autorefractor vs. streak retinoscopy in dogs

Objective To compare the Welch Allyn SureSight? wavefront autorefractor with retinoscopy in normal dogs. Animals studied Fifty privately owned dogs (100 eyes) of 20 breeds, free of ocular disease. Mean ± SD age: 5.7 ± 3.25 years (range: 6 months–13 years). Procedures The refractive error was determined in each eye by two experienced retinoscopists using streak retinoscopy as well as by an autorefractor operated by two different examiners. Measurements were performed before and approximately 30–45 min after cycloplegia was induced by cyclopentolate 0.5% and tropicamide 0.5% ophthalmic solutions. Results Mean ± SD noncyclopleged retinoscopy net sphere was ?0.55 ± 1.14 (range: ?3.75 to 3.5) diopters (D). Mean cyclopleged retinoscopy net sphere was ?0.52 ± 1.18 (range: ?4.25 to 2) D. Mean ± SD noncyclopleged autorefractor spherical equivalent (SE) was ?0.42 ± 1.13 D (range: ?3.36 to 2.73) D. Mean cyclopleged autorefractor SE was 0.10 ± 1.47 (range: ?5.62 to 3.19) D. Noncyclopleged autorefraction results were not significantly different from streak retinoscopy (whether noncyclopleged or cyclopleged, P = 0.80 and P = 0.26, respectively). Cyclopleged autorefraction results were significantly different from noncyclopleged or cyclopleged streak retinoscopy (P < 0.0001 in both states). There was no significant difference between noncyclopleged and cyclopleged streak retinoscopy (P = 0.97). Conclusions Noncyclopleged autorefraction shows good agreement with streak retinoscopy in dogs and may be a useful clinical technique. Cycloplegia does not significantly affect streak retinoscopy results in dogs.