A Novel Stress-Induced Sugarcane Gene Confers Tolerance to Drought, Salt and Oxidative Stress in Transgenic Tobacco Plants

Background: Drought is a major abiotic stress that affects crop productivity worldwide. Sugarcane can withstand periods of water scarcity during the final stage of culm maturation, during which sucrose accumulation occurs. Meanwhile, prolonged periods of drought can cause severe plant losses. Methodology/Principal Findings: In a previous study, we evaluated the transcriptome of drought-stressed plants to better understand sugarcane responses to drought. Among the up-regulated genes was Scdr1 (sugarcane drought-responsive 1). The aim of the research reported here was to characterize this gene. Scdr1 encodes a putative protein containing 248 amino acids with a large number of proline (19%) and cysteine (13%) residues. Phylogenetic analysis showed that ScDR1is in a clade with homologs from other monocotyledonous plants, separate from those of dicotyledonous plants. The expression of Scdr1 in different varieties of sugarcane plants has not shown a clear association with drought tolerance. Conclusions/Significance: The overexpression of Scdr1 in transgenic tobacco plants increased their tolerance to drought, salinity and oxidative stress, as demonstrated by increased photosynthesis, water content, biomass, germination rate, chlorophyll content and reduced accumulation of ROS. Physiological parameters, such as transpiration rate (E), net photosynthesis (A), stomatal conductance (gs) and internal leaf CO2 concentration, were less affected by abiotic stresses in transgenic Scdr1 plants compared with wild-type plants. Overall, our results indicated that Scdr1 conferred tolerance to multiple abiotic stresses, highlighting the potential of this gene for biotechnological applications.

Do Tobacco and Alcohol Modify Protective Effects of Diet on Oral Carcinogenesis?

Recent systematic reviews concluded that the frequent consumption of fruits and vegetables is inversely associated with the risk of oral cancer. We assessed this association, specifically comparing results obtained to nonsmokers and smokers, as well to nondrinkers and drinkers. We conducted a case-control study involving 296 patients with oral squamous cell carcinoma (cases) attended in 3 major hospitals of Sao Paulo, Brazil, paired with 296 controls, recruited from outpatient units of the same hospitals. Multivariate models assessed the effect of fruits and salads according to smoking and drinking. The intake of fruit was associated with the prevention of the disease in the specific assessment among light [odds ratio (OR) = 0.46; 95% confidence interval (CI) = 0.27-0.78) and heavy (OR = 0.30; 95% CI = 0.14-0.65) smokers. The same was observed for vegetables consumption. For nonsmokers, no fruit (OR = 50; 95% CI = 0.22-1.12) or vegetable (for tomato, OR = 0.53; 95% CI = 0.31-0.93) was associated with reduced risk of oral and oropharyngeal cancer. Similar results were found in the stratified analysis according to drinking status with OR = 0.51 (95% CI = 0.30-0.87) and 0.18 for fruits (95% CI = 0.07-0.45), respectively, for light and heavy drinkers. This observation suggests that the protective effect of fruit and salad intake may modulate the deleterious effects from tobacco and alcohol.

From cigarette smuggling to illicit tobacco trade

Background Tax policy is considered the most effective strategy to reduce tobacco consumption and prevalence. Tax avoidance and tax evasion therefore undermine the effectiveness of tax policies and result in less revenue for governments, cheaper prices for smokers and increased tobacco use. Tobacco smuggling and illicit tobacco trade have probably always existed, since tobacco's introduction as a valuable product from the New World, but the nature of the trade has changed. Methods This article clarifies definitions, reviews the key issues related to illicit trade, describes the different ways taxes are circumvented and looks at the size of the problem, its changing nature and its causes. The difficulties of data collection and research are discussed. Finally, we look at the policy options to combat illicit trade and the negotiations for a WHO Framework Convention on Tobacco Control (FCTC) protocol on illicit tobacco trade. Results Twenty years ago the main type of illicit trade was large-scale cigarette smuggling of well known cigarette brands. A change occurred as some major international tobacco companies in Europe and the Americas reviewed their export practices due to tax regulations, investigations and lawsuits by the authorities. Other types of illicit trade emerged such as illegal manufacturing, including counterfeiting and the emergence of new cigarette brands, produced in a rather open manner at well known locations, which are only or mainly intended for the illegal market of another country. Conclusions The global scope and multifaceted nature of the illicit tobacco trade requires a coordinated international response, so a strong protocol to the FCTC is essential. The illicit tobacco trade is a global problem which needs a global solution.

ENVIRONMENTAL TOBACCO SMOKE INDUCES OXIDATIVE STRESS IN DISTINCT BRAIN REGIONS OF INFANT MICE

Environmental tobacco smoke (ETS) leads to the death of 600,000 nonsmokers annually and is associated with disturbances in antioxidant enzyme capacity in the adult rodent brain. However, little is known regarding the influence of ETS on brain development. The aim of this study was to determine levels of malonaldehyde (MDA) and 3-nitrotyrosine (3-NT), as well as enzymatic antioxidant activities of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and superoxide dismutase (SOD), in distinct brain structures. BALB/c mice were exposed to ETS twice daily for 1 h from postnatal day 5 through postnatal day 18. Acute exposure was performed for 1 h on postnatal day 18. Mice were euthanized either immediately (0) or 3 h after the last exposure. Immediately after an acute exposure there were higher GR and GST activities and MDA levels in the hippocampus, higher GPx and SOD activities in the prefrontal cortex, and higher GST activity and MDA levels in the striatum and cerebellum. Three hours later there was an increase in SOD activity and MDA levels in the hippocampus and a decrease in the activity of all enzymes in the prefrontal cortex. Immediately after final repeated exposure there were elevated levels of GST and GR activity and decreased GPx activity in the hippocampus. Moreover, a rise was found in GPx and GST activities in the prefrontal cortex and increased GST and GPx activity in the striatum and cerebellum, respectively. After 3 h the prefrontal cortex showed elevated GR and GST activities, and the striatum displayed enhanced GST activity. Data showed that enzymatic antioxidant system in the central nervous system responds to ETS differently in different regions of the brain and that a form of adaptation occurs after several days of exposure.

Ectopic expression of a fruit phytoene synthase from Citrus paradisi Macf. promotes abiotic stress tolerance in transgenic tobacco

Abscisic acid (ABA) is an important regulator of plant responses to environmental stresses and an absolute requirement for stress tolerance. Recently, a third phytoene synthase (PSY3) gene paralog was identified in monocots and demonstrated to play a specialized role in stress-induced ABA formation, thus suggesting that the first committed step in carotenogenesis is a key limiting step in ABA biosynthesis. To examine whether the ectopic expression of PSY, other than PSY3, would similarly affect ABA level and stress tolerance, we have produced transgenic tobacco containing a fruit-specific PSY (CpPSY) of grapefruit (Citrus paradisi Macf.). The transgenic plants contained a single- or double-locus insertion and expressed CpPSY at varying transcript levels. In comparison with the wild-type plants, the CpPSY expressing transgenic plants showed a significant increase on root length and shoot biomass under PEG-, NaCl- and mannitol-induced osmotic stress. The enhanced stress tolerance of transgenic plants was correlated with the increased endogenous ABA level and expression of stress-responsive genes, which in turn was correlated with the CpPSY copy number and expression level in different transgenic lines. Collectively, these results provide further evidence that PSY is a key enzyme regulating ABA biosynthesis and that the altered expression of other PSYs in transgenic plants may provide a similar function to that of the monocot's PSY3 in ABA biosynthesis and stress tolerance. The results also pave the way for further use of CpPSY, as well as other PSYs, as potential candidate genes for engineering tolerance to drought and salt stress in crop plants.

Lung morphology and growth of rats exposed to tobacco smoke and alcohol

PURPOSE: Investigate the morphological effects of chronic exposure to tobacco smoke inhalation and alcohol consumption on the lungs and on the growth of rats. METHODS: Sixty male Wistar rats were divided into four groups: control, tobacco, alcohol, tobacco + alcohol, for a period of study 260 days. Morphological analysis was conducted by optical and electron microscopy. Rat growth was investigated by measuring the snout-anus length, body mass index and body weight. RESULTS: The three groups exposed to the drugs presented lower growth and lower weight than the control group. The percentages of alveolitis, bronchiolitis and the mean alveolar diameter were greater, particularly in the groups exposed to tobacco smoke, but were not significantly different from the control group. Electron microscopy revealed more intense apoptotic and degenerative lesions in the smoking group, while degenerative lesions in the lamellar bodies were more intense with the association of both drugs. CONCLUSIONS: This experimental model showed morphological alterations observed by electron microscopy, principally due to tobacco smoke exposure. Alcohol and tobacco hindered the growth of rats, such that tobacco showed a greater effect on body length and alcohol on body weight.