bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Regulation and Biochemical Action of Natural Fungicides in Tobacco
Authors: Eberhardt HJ 
Published: July 2016

Abstract
The biochemical interactions between the tobacco plant and a fungal pathogen are complex and poorly understood. Upon infection, the fungus overcomes the natural defence mechanism of the host by the lytic activity of enzymes and by suppressing the hypersensitive reaction of N. tabacum. The ability of the tobacco plant to resist a fungal attack is based on macroscopic properties and the biosynthesis of natural fungicides. The physical and biochemical character of the leaf surface (e.g. trichome exudates, cuticular components) may prevent the fungus from entering the organism. Constitutive natural fungicides such as phenolics and terpenes operate as enzyme inhibitors, or impair the germination of the fungal spores. Newly synthesized polysaccharides of the cell wall of leaf cells may delay the penetration of the fungus. Lignification of the surrounding cells occurs to protect the healthy tissue against attack. Toxic substances created during the melanization process of the tobacco plant can destroy the fungal cells. Biosynthesis of natural fungicides, such as phytoalexins, pathogenesis-related proteins and proteinase inhibitors is induced by exogenous or endogenous elicitors. These active protection systems may interfere with the fungal metabolism. Phytoalexins and pathogenesis-related proteins are highly effective defence responses which offer a broad spectrum of variability and resistance against a fungal infection. New strategies for engineering crop protection are based on these defence systems.
Rapid Near Infra-red Reflectance Analysis (NIRA) of Mainstream Smoke Collected on Cambridge Filter Pads
Authors: DiLuzio C , Morzilli S , Cardinale E 
Published: July 2016

Abstract
Near infra-red (NIR) reflectance spectroscopy has been used for rapidly and reproducibly measuring the NIR spectra of mainstream smoke collected on Cambridge filter pads and quantifying the chemical composition from the spectral data. This technique has four main advantages: speed, simplicity of sample preparation, multiple analytes from one scan of a sample, and non-destruction of the sample. The study has been conducted in our research laboratory to define the possible use of NIRA (Near Infra-red Reflectance Analysis) as an instrumental screening tool for analysing mainstream smoke collected on Cambridge Filter pads. A major advantage of this method is that it eliminates the use of dangerous chemicals such as cyanogen bromide or chloride involved with some standard assays. Using specific wavelengths, we are able to determine with acceptable accuracy water, nicotine and tar. Correlation coefficients of NIRA results compared with those obtained by standard methods are better than 0.9 for all analyses. NIRA cannot replace ISO standard methods, flow analysis or chromatography, but as a reliable screening analysis, it could reduce the routine work load by 80 %. These savings could be achieved by prescreening samples with NIRA and analysing only suspect samples by distillation or continuous flow analysis.
Conference Report - 50th “Deutsche Pflanzenschutztagung”, September 23-26, 1996, Muenster, Germany
Authors: Eberhardt HJ 
Published: July 2016

Abstract
From 23.-26. September 1996 the Biologische Bundesanstalt fuer Land- und Forstwirtschaft heldthe 50th ‘Deutsche Pflanzenschutztagung’ (German Plant Protection Conference) in Muensterwithmorethan 1000 participants. Approximately 350 presentations were classified into different specialities which were discussed in five parallel sessions. In addition, a poster session with 250 posters also included the culture and pesticide protection of the tobacco plant. The subjects treated in the various sessions were very broud. Besides the increasing importance of natural plant protection agents, modern biotechnological and genetic methods used for pest control and analysis of pest organisms in cultivars were a major discussion topic. Manufacturers of agrochemicals used the opportunity to present their newly developed products.
The Roles of Amino Acids and Sugars in the Production of Volatile Materials in Microwave Heated Tobacco Dust Suspensions
Authors: Coleman WM , Perfetti TA 
Published: July 2016

Abstract
For the first time, the role(s) of selected amino acids and sugars in the production of volatile compounds in microwave prepared heat treated tobacco suspensions (HTTS) has been unambiguously defined. The role can be expressed in two major reaction pathways:
1) Strecker degradation of amino acids and 2) amino acid/sugar Maillard-type reactions. The mechanism of the Strecker degradation was confirmed by the addition of selected 13C- labelled amino acids to the reaction suspension. The addition of the amino acid resulted in a dramatic increase in the concentration of the specific, appropriate, low molecular weight Strecker aldehyde in the headspace above the reaction suspension. The mechanism of the amino acid/sugar Maillard-type reactions was substantiated by: 1) adding a wide array of amino acids to the suspension;
2) by employing 15N-labelled amino acids; and
3) employing 13C-labelled sugars. Addition of amino acids to the suspension followed by heat treatment resulted in significant increases (2 ×) in the concentration of volatile pyrazines relative to the control. Most amino acids significantly increased the concentration of headspace pyrazines. Reactivity differences, as a function of sugars, was also demonstrated. Analysis of the headspace above suspensions incorporating 15N-labelled amino acids and 13C-labelled sugars revealed the 15N and 13C atoms to have been distributed throughout a wide array of volatile pyrazines. The distribution of the 15N atoms within the pyrazines was unique to the amino acid and the distribution of the 13C atoms was linked to the type of sugar employed. These results have documented for the first time in a heat treated tobacco formulation the mechanisms of amino acids and sugars in the production of volatile compounds which have documented intense sensory characteristics.
Variability of Peronospora Tabacina A. - An Isoenzyme Study
Authors: Edreva A , Delon R , Coussirat JC 
Published: July 2016

Abstract
The variability of P. tabacina A. populations was studied by using the isoenzymes of peroxidase (PO), malate dehydrogenase (MDH) and superoxide dismutase (SOD) as molecular markers. P. tabacina conidia/conidiophores from N. tabacum crops cultivated in distant areas of Europe (France and Bulgaria) were investigated during a long period of time (1978-1992). It was found that no variations of P. tabacina as a function of space and time occurred. The data point to the genetical stability of the presently spread strain of the pathogen and the lack of processes of new strain formation. However, a significant variability of P. tabacina as a function of host plant was established. Suspension of conidia/conidiophores of P. tabacina originating from N. tabacum (P 48 cv.) was used to inoculate the wild species N. repanda. First conidia/conidiophores of P. tabacina produced on the new host plant (designated as Pt/Nr) as well as those from the “classical” host, N. tabacum (designated as Pt/Nt) were analysed. Thus, two types of P. tabacina (according to their origin) were compared. It was shown that one MDH and most PO isoenzymes present in Pt/Nt were not observed in Pt/Nr; these isoenzymes repressed following the transfer were common for Pt/Nt and its N. tabacum host. Moreover, in conidia/conidiophores of Pt/Nr new isoenzymes appeared, namely one major PO, one MDH and a block of three SOD isoenzyme components. These isoenzymes were common for Pt/Nr and the new host, N. repanda. It is noteworthy that all fungus specific isoenzymes present in Pt/Nt (one PO, five MDH and seven SOD components) were conserved in Pt/Nr. The results reveal molecular mechanisms underlying relationships between host plants and obligatory fungal pathogens, such as P. tabacina. They could be used in blue mold epidemiology research.
Chiral-Gas Chromatography-Selected Ion Monitoring-Mass Selective Detection Analysis of Tobacco Materials and Tobacco Smoke
Authors: Perfetti TA , Coleman WM 
Published: July 2016

Abstract
A novel method for the detection, separation, and quantification of the optical isomers of nicotine has been developed. The method has been applied to analyse extracts of tobacco seeds, processed tobacco suspensions, reconstituted tobacco sheet materials, individual tobacco varieties, blends of tobaccos, and cigarette smoke condensate. The methodology does not involve any further sample preparation other than that which is normally used to analyse tobacco alkaloids by the modified method of Gordon et al. (73), or the standard FTC smoke analysis routinely performed by most tobacco and smoke analysis laboratories. Near baseline resolution was obtained for enantiomers, yielding a lower detection limit of approximately 2 % d-nicotine in a mixture of d-and l-nicotine. There was essentially no d-nicotine found in any of the tobacco samples. Detectable levels of d-nicotine were found in most of the samples of cigarette smoke condensate when the cigarettes were smoke by the FTC method. The presence of Oriental tobacco in the cigarette appeared to be related to whether d-nicotine was generated in the mainstream cigarette smoke condensate. When the same cigarettes were smoked under a more stressful puffing regime the level of d-nicotine in the smoke did not increase and in some cases the level of d-nicotine decreased. This work supports prior literature that detected and quantified the presence of d-nicotine in cigarette smoke condensate.
Chiral-Gas Chromatograpy-Selected Ion Monitoring-Mass Selective Detection Analysis of Secondary Alkaloids in Tobacco and Tobacco Smoke
Authors: Perfetti TA , Coleman WM 
Published: July 2016

Abstract
Chiral gas chromatography-mass selective detection has been successfully employed in the analysis of secondary alkaloids in selected tobacco materials and cigarette smoke condensate. No extensive sample preparation is involved. A lower detection limit of ~2 % d-nornicotine, d-anabasine and d-anatabine in a mixture of l and d-isomers was achieved. The levels and the enantiomeric ratios of nicotine, nornicotine, anabasine and anatabine varied in different tobacco types. The enantiomeric ratios of nicotine, anabasine and anatabine in mainstream cigarette condensate also varied but were generally representative of the enantiomeric ratios for the alkaloids found in the leaf. The enantiomeric ratio for nornicotine in mainstream cigarette condensate also varied and was not representative of the enantiomeric ratios for the alkaloids found in the leaf. Preferential decomposition or racemization may account for the differences seen in the yields of isomers of nornicotine transferred to the mainstream smoke condensate. An experiment was conducted to determine if the d-nornicotine present in tobacco contributed to the yield of d-nicotine in mainstream smoke condensate. The results of that experiment indicated that the yield of d-nicotine transferred to mainstream smoke did not change significantly when either large levels of endogenous nornicotine were present in the leaf or when large levels of exogenous levels of d-, l-nornicotine were applied to the tobacco rod prior to smoking. The limiting factor in the production of d-nicotine in mainstream cigarette smoke condensate may be the concentration of methyl radicals present to react. Further work must be conducted to unravel the mechanism involved in the production of d-nicotine in cigarette smoke condensate.
Evaluation of the Efficacy of CGA 245704 Combined or Not with CGA 329 351 (Mefenoxam) for the Control of Tobacco Blue Mold (Peronospora Tabacina): Results of Four Years of Experiments
Authors: Delon R , Cailleteau B , Verrier JL , Tanne MN , Sylvestre M 
Published: July 2016

Abstract
A compound for activating systemic resistance (CGA 245 704), in the chemical class of benzothiadiazoles, was studied since 1993 for the control of tobacco blue mold (Peronosporatabacina A.) in seedbeds and in the field. One foliar application of CGA 245 704 at 1.6 g active ingredient/hl every 14 days protected tobacco plants against blue mold but protection was not total. Mixed with mefenoxam (CGA 329 351) at 16 g active ingredient/hl the protection is equivalent to standard Acylon¯ TC (25 % metalaxyl, 50 % maneb) applied as foliar spray at 0.160 kg/hl (40 g active ingredient metalaxyl per hl). This allows a reduction in the quantity of fungicides dispersed in the environment and the pesticide residues on the tobacco leaves. At the rate applied, no phytotoxic effects were observed in seedbeds or in the field.
The Incidence and Consequences of Filter Vent Blocking Amongst British Smokers
Authors: Baker RR , Dixon M , Hill CA 
Published: July 2016

Abstract
Vent blocking, the intentional or unintentional covering of the filter ventilation holes during smoking, is an aspect of smoking behaviour which could influence mainstream smoke yields. This study was designed to determine if, and to what extent, vent blocking by smokers’ lips occurs. Three groups of British smokers were asked to smoke their own brand of cigarette which was either an unventilated filter brand, or one of two brands containing different levels of filter ventilation. 300 Smokers were used in each group and the filter butts were collected. Approximately 10 filter butts per smoker were collected. The filter tipping papers were removed and treated with a ninhydrin solution. This stained the saliva imprint on the paper so that the mouth insertion depth of the cigarette could be measured. In addition, levels of retained nicotine on the filters were also determined. This, together with the known filtration efficiencies of the filter, enabled an estimate to be made of the mainstream nicotine yield of the cigarette during the smoking. The results indicate that British smokers have an average insertion depth of about 8.5 mm. 85 % of the ventilated filters examined showed no vent coverage by the smokers’ lips, 15 % showed some coverage. Based on the techniques used in the present study it appears that the presence or absence of filter ventilation zone coverage by lips is not reflected in the estimated nicotine yields to smokers. It is likely that other smoker behaviour factors have a more substantial role in determining nicotine yields within each cigarette delivery category.
Internal Standard-based Analytical Method for Tobacco Smoke Vapor Phase Components
Authors: Omori F , Higashi N , Chida M , Sone Y , Suhara S 
Published: July 2016

Abstract
We developed an internal standard-based method to analyze the vapor phase components of mainstream smoke. This method collects vapor phase components from sample cigarettes, which are smoked by a linear automatic smoking machine in a sampling bag. An internal standard gas was introduced to the bag. A 6-port valve with a 2-ml sampling loop was placed between the vapor phase smoke outlet of the smoking machine and the bag to regulate the volume of the internal standard. The mixed gas sample was then introduced, by an automatic injection device developed in-house, to a gas chromatograph (GC) for ten successive analyses. The sample in the bag was analyzed every two hours to assess the time serial changes of vapor phase smoke components as well as of the internal standard. After 18 hours, in the tenth analysis, the amounts of 37 vapor phase components decreased by less than 5 % from those in the first analysis. The repeatability of the sample analysis was assessed and 45 vapor phase components had coefficients of variation of less than 5 %. The overall reproducibility of this method including tobacco samples and instruments was also assessed using five other sampling bags and achieved coefficients of variation of less than 6 % for 42 vapor phase components. The advantages of this method include capability to handle 10 tobacco samples in a serial manner, capability to collect both the vapor phase and semivolatile components, and precise, easy and continuous component analyses. We also present the results of multivariate analyses for the vapor phase and semivolatile components from 59 sample cigarettes.
Sampling and Analysis Techniques for Odorous Volatile Organic Compounds (VOCs) from Concentrated Aged Sidestream Smoke (SSS)
Authors: Taylor HJ , Winter DB , Miranda EJF , Pereira da Silva JR 
Published: July 2016

Abstract
This work is part of a long term study aimed at determining the odorous Volatile Organic Compounds (VOCs) in Environmental Tobacco Smoke (ETS) deposited on clothing. In this preliminary phase of the study sidestream smoke (SSS) rather than true ETS was used, for the following reasons. Firstly, the sampling system had to be modified in order to increase the concentration of odorous VOCs collected so that the later analytical stages could proceed. This meant that the sampling system was developed to collect concentrated SSS on cloth. Secondly, the cigarette butts were removed from the system so that they did not contribute to the odour; and thirdly the cloth was left to age for 48 hours. Therefore, technically, the study was the determination of the odorous VOCs in aged concentrated SSS deposited on cloth; this will be referred to as ‘aged SSS’ from this point onwards throughout this paper. This paper describes the method development of sampling and analysis techniques for odorous VOCs in aged SSS deposited on cloth. In addition, this paper demonstrates the processes of heartcutting and the mass spectral identification of odorous components using a concentrated tobacco steam distillate extract. A sampling chamber was constructed to allow the aged SSS to be deposited on the surface of the fabric, and to ensure that the amount of smoke deposited on the cloth was sufficiently high to conduct further analyses. The fabric was then desorbed via a purpose built purge- and-trap system to release the volatiles onto selected adsorbents. Each adsorbent in turn was solvent desorbed and a concentrated extract obtained. The aged SSS extracts were then directly injected into a multidimensional Gas Chromatography/Mass Spectrometry (GC/MS), and GC profiles obtained. These chromatographic profiles facilitate both the direct comparison of the range of VOCs trapped and desorbed from each adsorbent, and the identification of odorous regions when used in conjunction with the odour port. The aged SSS chromatograms presented in this paper only show the range of VOCs collected by the different adsorbents. Further experiments were also conducted with a concentrated tobacco steam distillate extract. These results were obtained by directly injecting the extract into the multidimensional GC/MS system, connected to an odour port. Volunteers were then asked to sensorially evaluate the odour of the extract and to identify any odorous notes during the analysis. Two concentrated tobacco steam distillate extract chromatograms are presented.
The Thermodynamics of Tobacco-Water Interactions
Authors: Banyasz JL 
Published: July 2016

Abstract
An equation to describe the water sorption isotherm of tobacco is developed based on a model of the tobacco-water system as a mixture or solid solution comprised of water and water binding sites of many different kinds. It is assumed that free water has an activity coefficient of one. The result is an equation that predicts moisture content as a function of relative humidity given the numbers of each of the different kinds of sites and the associated water binding equilibrium constants. It is shown that this multi-site equation reduces to a one site equation if the different kinds of water binding sites are symmetrically distributed with regard to their affinity for water. The result is a two parameter, average site equation that fits water sorption data for tobacco over the range of 10-80% relative humidity. The average site equation is identical to the equation derived by BRUNAUER, EMMETT and TELLER for binding to surface sites (1). The two models start from very different points of view but come to the same conclusion because they are ultimately based on thermodynamics which is indifferent as to the physical nature of the sites. Inferences as to the microscopic nature of water binding sites cannot be made from thermodynamic isotherm equations. In order to describe the effects of water on the physical properties of tobacco the solution analogy is extended further. If tobacco is a mixture or solution of unhydrated sites, hydrated sites and free water, then the value of a physical property should be a function of the concentrations of those species and the associated partial molar values of the property. As the total moisture content changes the distribution of species will change and, in turn, change the properties. Applications of this rationale are presented for heat capacity, thermal diffusivity and the kinetics of the Browning reaction. The results demonstrate that the parameters derived from water sorption data play a more general role in the thermodynamics of the tobacco-water system.
The Quality Estimation of Different Tobacco Types Examined by Headspace Vapor Analysis
Authors: Hasebe H , Suhara S 
Published: July 2016

Abstract
In order to judge the quality of tobacco leaf, it is necessary to conduct sensory smoke evaluations. However, these are subjective and the results are difficult to quantify. Therefore, we have attempted to establish a quantitative method for evaluating tobacco quality by comparing results of headspace analysis. Forty-seven leaf samples of different types (flue-cured, Burley, Oriental) were analyzed. The first step in this study was to have a panel of experts smoke cigarettes made from the test tobaccos and have them evaluate 10 sensory attributes. The scores were then analyzed by the technique of principal component analysis (PCA). Results showed that the score for the flavor note attribute indicated the type of tobacco and the scores of the other 9 attributes were combined as a total to indicate smoking quality. Following the sensory study, headspace vapors of the test tobaccos were analyzed with a headspace sampler, gas chromatography, mass spectroscopy system (HS-GC-MS), in which the gas sampling loop and the HS-GC transfer line were deactivated. In order to obtain conditions for good reproducibility, the heating temperature and time of the headspace vials were examined. PCA was performed for the headspace vapor (HSV) analysis results for 31 selected peaks. The first and second principal components could be used to classify tobacco types. The third principal component partially indicated differences of smoking qualities. Finally, multiple regression analysis was performed on the HSV analysis results in order to estimate the smoking quality scores. The regression model of all samples combined had a low regression coefficient. Then, we separated the results of the three tobacco types, as we considered that the headspace data might reveal information about the classifications themselves. The final outcome was a regression model that could be applied to each type with a higher accuracy. The variables that entered the models were compared.