Tracheal Morphologic and Protein Alterations Following Short-Term Cigarette Mainstream Smoke Exposure to Rats

A short-term 5-day nose-only cigarette smoke exposure study was conducted in Fisher 344 rats to identify smoke-induced tracheal protein changes. Groups of 10 male and female 5 week old rats were assigned to 1 of 4 exposure groups. Animals received filtered air, or 75, 200 or 400 mg total particulate matter (TPM)/m³ of diluted 3R4F Kentucky reference cigarette mainstream smoke. Exposures were conducted for 3 hrs/day, for 5 consecutive days. Tracheas from half the rats were processed for pathology, and tracheas from the other half of the rats frozen immediately for proteomics. We hypothesized that smoke will activate tracheal inflammatory, apoptotic, proliferative, and stress-induced pathways. Mucosal epithelial toxicity from the inhaled material was evidenced by cilia shortening and loss of tracheal mucosal epithelium in smoke-exposed animals. Mucosal thinning occurred in all smoke-exposed groups with hyperplastic reparative responses in the 200 and 400 mg TPM/m³ groups. Tracheal lysates from control vs. treated animals were screened for 800 proteins using antibody-based microarray technology and subsequently the most changed proteins evaluated by Western blot. Tracheal proteins expressed at high levels that were markedly increased or decreased by smoke exposure depended on dose and gender and included caspase 5, ERK 1/2 and p38. Signaling pathways common between the morphologic and protein changes were stress, apoptosis, cell cycle control, cell proliferation and survival. Changes in identified proteins affected by smoke exposure were associated with tracheal mucosal pathology, may induce functional tracheal changes, and could serve as early indicators of tracheal damage and associated disease.     

Protocol: a medium-throughput method for determination of cellulose content from single stem pieces of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Background

Lignocellulosic biomass is an important renewable resource for biofuels and materials. How plants synthesise cellulose is not completely understood. It is known that cellulose synthase complex (CSCs) moving in the plasma membrane synthesise the cellulose. CESA proteins are the core components of CSC. In Arabidopsis, in vitro mutagenesis of proteins followed by complementation analysis of mutants lacking the gene represents an important tool for studying any biological process, including cellulose biosynthesis. Analysis of a large number of plants is crucial for these types of studies.

Results

By using aspiration rather than centrifugation to remove liquids during various stages of protocol, we were able to increase the throughput of the method as well as minimise the sample loss. As a test case, we determined cellulose content of wild type and secondary wall cesa mutants across the length of primary shoot which was fond to be rather uniform in 7-week-old plants. Additionally, we found that the cellulose content of single mutants was comparable to the higher order mutants.

Conclusions

Here we describe a medium-throughput adaptation of Updegraff’s method that allowed us to determine cellulose content of 200 samples each week.

     

Effect of pruning intensity on peach yield and fruit quality

Light, medium and heavy pruning treatments were used with one unpruned as check (control) in Flordasun, Flordaking and Saharanpur Prabhat peaches. Fruit yield decreased with the increase in severity of pruning in Flordaking and Saharanpur Prabhat peaches, whereas, medium pruning treatment gave highest yield in Flordasun peach. Pulp weight, stone weight, pulp-stone ratio, ascorbic acid, sugar acid ratio and moisture content were not affected by pruning levels. However, fruit weight, size, TSS, sugar and acid content were significantly increased by pruning in Flordasun peach. Almost all the physico-chemical characters were significantly affected by pruning in Flordaking and Saharanpur Prabhat peaches, in which medium and heavy pruning treatments performed better, respectively.     

Inhibition of egg development by phosphine in the cosmopolitan pest of stored products Liposcelis bostrychophila (Psocoptera: Liposcelididae)

Phosphine-induced delay in development of eggs was investigated as a mechanism of resistance to this fumigant in Liposcelis bostrychophila Badonnel. One-day-old eggs of a susceptible and a strongly resistant strain of L bostrychophila were exposed to a range of phosphine concentrations for 6days at 30 (+/- 1) degrees C and 70 (+/- 2)% RH. Delay in mean hatching period occurred in both susceptible and resistant eggs, although it was more pronounced in the latter. A maximum delay of 2.65 days was recorded for eggs of the susceptible strain at 0.01 mg litre(-1) (the highest concentration at which eggs survived) and 13.39 days for the resistant strain at 1 mg litre(-1) (the highest concentration tested). Delay in egg development time was positively correlated with increasing phosphine concentration. Our results reveal that the most successful strategy to control resistant L bostrychophila is to apply relatively low concentrations of phosphine for extended exposure times (eg 0.05 mg litre(-1) for 16 days) that allow all eggs to hatch to the much less tolerant nymph stage.