Inflammation markers in the serum of salt miners

The inflammation markers alpha-1-antitrypsin (AAT), Clara cell protein (CC-16), soluble interleukin-2-receptor (IL-R) and the soluble adhesion molecule E-selectin, the intercellular adhesion molecule (ICAM-1) and the vascular adhesion molecule (VCAM-1) were determined in the serum of 195 salt-exposed miners to analyse dose-response relationships between markers and potash dust. Alpha-1-antitrypsin, Clara-cell protein, IL2-R, E-selectin and VCAM-1 were not changed by salt exposure, however the ICAM-1 level in the serum fell slightly as the salt exposure increased. This effect was strongest in the group of smokers, still visible in the group of ex-smokers, no effect was seen in non-smokers. Markers, with the exception of VCAM-1, were influenced by tobacco exposure. Since markers were not elevated in relation to salt dust exposure, the results do not support an inflammatory effect of potash dust on the respiratory system.     

Genomic factors responsible for abnormal morphology of pollen tubes in the interspecific cross Nicotiana tabacum ×N. rustica

Nicotiana tabacum shows unilateral pollen-pistil incongruity with N. rustica. If N. tabacum is pollinated with N. rustica, growth of the pollen tube is arrested in the middle of the style, and abundant callose deposition, tube swelling and tube winding are observed. An attempt was made to clarify the genomic factors responsible for this pollen-pistil incongruity. N. tabacum was pollinated with N. paniculata or N. undulata, progenitors of amphidiploid N. rustica. When pollinated with N. undulata, growth of the pollen tube was arrested in the middle of the style and showed abnormal morphology similar to that with N. rustica, but when pollinated with N. paniculata the pollen tube reached near the base of the style and was almost normal in appearance. These observations suggest that the factors responsible for the pollen tube abnormality of N. rustica are derived from the N. undulata genome.We also used N. sylvestris, N. glutinosa and N. otophora as pistilar parents and N. rustica or its progenitors as pollen parents to examine the genomic factors of the pistilate parents. The pollen tube features of these three species in the pistils of N. sylvestris were similar to those in the pistil of N. tabacum. Received: 25 October 1999 / Revision accepted: 2 February 2000     

The value of gametoclonal variation in breeding for quantitative traits in flue-cured tobacco (Nicotiana tabacum L.)

Summary In tobacco (Nicotiana tabacum L.), anther-derived doubled haploid populations have been shown to exhibit large amounts of unexpected genetic variation and a severe depression in cured leaf yield when compared to conventionally inbred genotypes from comparable sources. A previous study had predicted that the yield depression observed in a doubled haploid population-derived from a near homozygous cultivar, NC95, might be overcome through a recurrent selection program. In the current study, progress from three cycles of full-sib family selection for improved yield in an anther-culture derived population of NC95 was measured, as well as the remaining genetic variation within the population. A design II experiment was conducted in the population following three cycles of selection. Results indicate that the NC95 yield level has been recovered in the third selection cycle population. Although most of the genetic variation in the population appears to be exhausted, the additive genetic variance among maternal half-sib families for yield is significant, and it appears that continued yield improvement can be made through recurrent selection. Significant additive-genetic variance for yield was found among maternal half-sib families but was essentially zero among the paternal half-sib families, suggesting that remaining genetic variation is not being transmitted through pollen. One possible explanation results from the phenomenon of DNA amplification that can occur during the anther culture process, and that may enable extraordinary recombinational events and reduce the viability of male gametes.     

Activities of hydrolytic enzymes in callus cultures of tobacco during organogenesis

Starch, total sugars, reducing sugars and protein contents and the specific activities of hydrolytic enzymes such as amylase, Phosphorylase, soluble acid invertase, wall-bound acid invertase, sucrose synthetase, acid and alkaline phosphatases and ribonuclease were determined in root forming, shoot forming and non-organ-forming callus cultures of tobacco. Organ-forming cultures not only showed higher amounts of the above metabolites but also higher enzyme activities compared to non-organ-forming cultures. The activities of these enzymes in relation to organogenesis is discussed.     

Mendelian randomization in health research: Using appropriate genetic variants and avoiding biased estimates

Mendelian randomization methods, which use genetic variants as instrumental variables for exposures of interest to overcome problems of confounding and reverse causality, are becoming widespread for assessing causal relationships in epidemiological studies. The main purpose of this paper is to demonstrate how results can be biased if researchers select genetic variants on the basis of their association with the exposure in their own dataset, as often happens in candidate gene analyses. This can lead to estimates that indicate apparent “causal” relationships, despite there being no true effect of the exposure. In addition, we discuss the potential bias in estimates of magnitudes of effect from Mendelian randomization analyses when the measured exposure is a poor proxy for the true underlying exposure. We illustrate these points with specific reference to tobacco research.     

Schistosoma mansoni: antigenic community between schistosomula surface and adult worm incubation products as a support for concomitant immunity

The use of protective monoclonal antibodies has enabled us to demonstrate antigenic community between a 38-kDa schistosomula surface molecule and a 115-kDa component derived from adult worms. Injection of adult worms in rats also led to the production of antibodies specific for the 38-kDa antigen, suggesting that the 115-kDa adult worm molecule could act as an inducer of the protective immune response raised against young invading parasites.     

Cessation experiences and quitting perspectives of Jordanian cancer patients who smoke

ObjectivesTo describe quitting experiences of cancer patients in a Cancer Center in Jordan; to study patients’ perceptions regarding the process of smoking cessation; and to provide insights about patients in this difficult setting in order to inform oncology practitioners with regards to how improve perceptions and skills related to quitting.MethodsAn Arabic cross-sectional questionnaire was developed to evaluate smoking and quitting behaviors in the context of cancer. The tool used as its framework the Theoretical Domains Framework to capture quitting perceptions of cancer patients who smoke, as well as social, environmental, and system-level factors that influence quitting. Eligible patients who were treated at the Center (both in-patient and out-patient settings) and who were current smokers or who smoked up to the time of cancer diagnosis were eligible. Patients were interviewed between July, 2018 and January 2020 using two versions of the questionnaire: an ‘ex-smokers’ version, and a ‘current smokers’ version.ResultsOnly a third of subjects (104/350) had been smoke-free for at least 30 days. Both smokers and ex-smokers generally felt that quitting was important, but mean importance and confidence scores (out of 10) were significantly lower in current smokers (8.2 versus 9.1, p-value=0.002; 6.4 versus 8.7, p-value=0.000). Roughly 31% of subjects believed smoking harms were exaggerated and that smoking was not an addiction. About 62% of subjects agreed quitting required skills, and 78.5% felt the steps to quit were clear, but across several listed strategies for quitting, use of these was limited (even in ex-smokers). Among current smokers, roughly a third exhibited forms of cessation fatigue.ConclusionJordanian cancer patients who smoke present with limited knowledge about the quitting process. Even when some success is observed, low rates of utilization of specific quitting strategies were observed, highlighting the need for better counseling about quitting.     

纳豆激酶基因的优化设计、合成及其在烟草叶片中的瞬时表达

根据植物偏爱密码子优化设计、合成纳豆激酶基因sNK,利用重叠延伸PCR法在其中插入番茄果实特异性表达基因E8的第一内含子构成sNKi基因,通过农杆菌渗透法将这两种基因渗入到烟草NC89叶片中并实现瞬时表达。通过RT-qPCR法将两种基因在烟草叶片中转录水平的表达量进行比较,结果表明两种基因在烟草叶片中均表达,且sNKi基因的表达量显著高于sNK基因;通过纤维蛋白平板法在两种基因的瞬时表达样品中均能检测到纤溶酶活性,表明目的基因在烟草叶片中可正常翻译并表现出溶栓活性,且sNKi基因在翻译水平的表达量显著高于sNK基因。表明内含子对人工合成的纳豆激酶基因的瞬时表达具有显著的促进作用。     

烟草品种Beinhart1000-1抗黑胫病基因的QTL定位

为研究烟草黑胫病不同亲本来源的抗性遗传规律,定位抗性基因位点,本研究利用抗黑胫病品种Beinhart1000-1构建了220个F2分离群体。通过病圃接种鉴定和遗传分析,确定Beinhart1000-1对烟草黑胫病的抗性由多基因控制。利用筛选到的70对稳定SSR引物对烟草黑胫病抗性进行了QTL分析,绘制了一张包含14条染色体的遗传连锁图谱,且定位到5个与烟草黑胫病抗性紧密相关的QTLs,分别在2、3、3、6、12号染色体上,其贡献率分别为6.2%、6.0%、6.7%、5.6%和5.1%。此结果使烟草黑胫病抗性研究进一步深入,推进了烟草黑胫病分子标记辅助选择。     

Evidence for a rapid structural change in TMV-A-protein near neutrality

Titration of TMV-A-protein from pH 8 to 7 (20°C) or raising the temperature from 4° to 20°C (pH 7) produces, within a few minutes, a reversible change in the aromatic region of the CD-spectrum, before any extensive aggregation has taken place. This spectral change is solely a matter of the conditions of the solution and not of the history of the protein. There is no further CD-change during the slow aggregation process. Thus there must be some proton-uptake within the A-protein. The results are discussed with regard to the different interpretations of the role of A-protein or double-disc in the elongation-step of TMV-“in vitro” -self-assembly.