Determination of mercaptobenzimidazol and other thyreostat residues in thyroid tissue and meat using high-performance liquid chromatography-mass spectrometry.

This paper describes a method for extraction of tapazol, thiouracil, methylthiouracil, propylthiouracil and mercaptobenzimidazol (MBI) from thyroid tissue. The solid-phase extraction procedure is optimized to obtain the maximum results for the main thyreostats including MBI. Different combinations of sample application, column conditioning and wash steps were tested. The analytes were extracted from the matrix with methanol. After solid-phase extraction they were derivatised with 7-chloro-4-nitrobenzo-2-furazan. Determination is carried out using liquid chromatography-electrospray mass spectrometry. The identification of the analytes was performed according to the final revision of the EU criteria (93/256/EC decision). The detection capability was 20 microg kg(-1) for all mentioned thyreostats.

Wolof adolescents' attitudes toward old people.

Studies of attitudes toward old people have focused on American samples. In the present investigation, an existing sentence completion instrument (2) was adapted to responses of Wolof adolescents in order to elicit Ss' spontaneous responses. Secondary school students (672) ranging in age from 17 to 20, served as Ss. Scoring categories were partially derived from Golde and Kogan's procedure (2), and two independent judges coded the material with a high level of agreement. The results confirmed the hypothesis of differences in beliefs and attitudes of Wolof and American samples and the relatively unfavorable attitudes of Wolof adolescents about old people as was shown in a previous study (6).

Retrospective considerations in training teachers regarding problems faced in adolescence.

With the help of a questionnaire addressed to 276 training teachers, we investigated the difficulties encountered by these adults during their adolescence with their teachers, their parents and their friends. Three-quarters of our subjects had trouble with their parents and their friends, while only half of them had trouble with teachers. A great proportion (40%) of those who had trouble with their teachers laid the blame on themselves rather than the teachers. Concerning parents, father's authoritarianism received the most criticism and subjects complained that they had little personal freedom. A considerable proportion of subjects (34%) attribute difficulties with their former comrades to themselves.

Perception of the causes of rowdyism in Senegalese schools.

The causes of rowdyism in class as perceived by 882 secondary school students in Senegal fell into the following categories: teachers' personalities (mentioned in 37.1% of the answers), teachers' ways of teaching (29.4%), teachers' attitudes toward pupils (19.8%), and pupils' attitudes (11.1%). If we consider the variables, sex and socio-economic status of the parents, the categories remain remarkably stable.

Mass spectrometric detection of and similarities between 1-androgens.

Regularly new anabolic steroids appear on the black market. In most cases these substances are marketed on websites or are confiscated during inspections. 1,(5alpha)-Androstene-17beta-ol-3-one, also known as 1-testosterone, is one of these substances presented to body-builders as a nutritional supplement or a pro-hormone. 1-Testosterone closely resembles the natural hormone testosterone except for a 1,2-double bound instead of a 4,5-double bound. 1-Androstene-3beta,17beta-diol is transformed into 1-testosterone after oral administration. 1-Testosterone, 1-androstene-3beta,17beta-diol and some other related 'new' anabolic steroids were studied with gas chromatography coupled to mass spectrometry (GC-MS) and Liquid chromatography coupled to tandem mass spectrometry (LC-MS2) methods. Similarities in spectra to known analytes, which may lead to pitfalls in the interpretation of the derivatised analytes, are discussed.

Both RNA level and translation efficiency are reduced by anti-sense RNA in transgenic tobacco.

The effect of anti-sense RNA on the expression of the bialaphos resistance (bar) gene which encodes phosphinothricin acetyl transferase (PAT), was analysed in tobacco. Transient expression studies revealed that an anti-bar RNA with sequence complementarity to the complete bar coding region, inhibits PAT synthesis. To quantify the phenomenon, SR1 tobacco cells were transformed twice to introduce first a hybrid bar gene with a reporter gene and in a second instance an anti-bar gene. A first cycle transformant and a double transformant derived herefrom in which PAT synthesis was reduced to only 8%, were studied in detail. The interference of the anti-sense gene with the expression of the bar gene is manifested at least two levels. First, the bar mRNA steady state level is significantly reduced relative to the parental whereas the transcript level of the reporter gene is unchanged. Comparison of bar mRNA levels in total and single stranded (ss) RNA preparations demonstrated that little if any stably base-pairing bar and anti-bar RNA accumulates. Secondly, a three fold reduction of PAT synthesis per bar mRNA is observed. This supposes that because of unstable interactions with the complementary anti-bar RNA either a substantial part of the bar mRNA detected does not enter the cytoplasm and/or that in the cytoplasm the bar mRNA is less efficiently translated. It is not clear if or how the reduced bar mRNA level is related to such unstable interactions.

Nuclear transcriptional activity of the tobacco plastid psbA promoter.

The plastid psbA promoter of tobacco was used with the aim to construct plastid specific marker genes. Upon transfer to the tobacco nuclear genome the plastid promoter fragment appeared to specify a messenger RNA. Placed 5' to the bar or nptII coding sequences the level of expression is sufficient to obtain a selectable phenotype. The transcription start site in the nucleus is site specific and is located 4 nucleotides downstream relative to the start site used in plastids. Translational fusions of the psbA coding sequence with the nptII and bar coding sequences revealed that the psbA leader sequence and the psbA translation start codon, being the second ATG codon, are recognized by the plant cytoplasmic translation apparatus. A promoter cassette utilisable in both E. coli and tobacco, was obtained by placing the CaMV 35S enhancer 5' to the psbA promoter.

How conformist Senegalese adolescents consider themselves to be.

Conformism seems to be of negative value in most European cultures as it is understood to rule out originality and creativity. In "transitional" societies such as the Senegalese one, at the crossroads of diverse influences, Western, Eastern and traditional African, the conception of conformism is slightly different, as we found when we investigated a group of schoolgoing adolescents. Results show that group pressure, though very strong, does not exclude individual initiative and a fair amount of free-will, and that this is in keeping with the traditional systems of values, understood in their appropriate context and meaning.

Senegalese adolescents and the need to control theft and criminality.

To several African nations, the access to international sovereignity has been concomittant with a crisis of values: the pressure of urbanization and industrialization have caused deep frustrations and called for a number of painful adjustments. To sample a measure of the changes that are still in process we asked 950 Senegalese secondary school students to comment upon their attitudes towards the rampant criminality, (particularly theft and murder) in their young nation. Three-quarters of answers were in favour of greater severity, but the remainder advocated tolerance, a sign that the traditional unanimity against criminality is now over.

Meaning and importance of the practice of religion amongst adolescents in Senegal.

In view of the growing importance of religion in Senegal, 950 Wolof speaking secondary school students were asked to comment upon the meaning and importance they gave to the practice of religion, and whether they believed it had any consequence on their lives and their country at large. An analysis of answers provided shows a large predominance of the practice of religion due to several reasons; historical, political and social, despite a minor trend of peripheral contest (10% of subjects said they don't believe in destiny nor in the importance of religious practice). Likewise the belief in the idea of destiny, i.e. that one's life was decided beforehand, did not seem to contradict the largely expressed need to be actively involved in the economic development of the country.

Attitudes of Senegalese schoolgoing adolescents towards tobacco smoking.

Results show that tobacco smoking is a widespread phenomenon among Senegalese adolescents for several important reasons: economic (the intensive advertisement campaigns in favor of tobacco smoking), cultural (the ambivalence of traditional attitudes of Western urbanization, and the attractiveness of the Western way of life), psychological (the traumas of modernism on a basically poor developing country). Despite this alarming picture, signs point to an effective preventive strategy aimed mainly at schoolgoing adolescents and based on joint legal, scientific, cultural, and even religious action.

Use of drugs among Senegalese school going adolescents.

Though it may appear more severe and dramatic in most industrialized nations, drug addiction has also become a matter for concern in some developing nations. The problem is even more complex when, prior to the advent of colonialism and the adoption of Western values by those countries, there already existed traditional forms of drug addiction. This paper examines the attitudes of Senegalese school-going adolescents to the problem of drug addiction. It describes the nature, development, and perception of drug addiction in the country from an historical and sociological point of view. It shows the tolerance of Senegalese society toward drugs - some were used in traditional medicine - and its rejection of "hard" and intermediate drugs, as they are viewed negatively by the society. The authors finally analyze the motivations of the drug addicts which also indicate, in Africa as in the West, a crisis of identity reflecting a global crisis of civilization.

Beggary in West Africa.

Westerners visiting Africa for the first time are often surprized --if not shocked--at the large number of beggars in the streets and the relative ease with which people solicit or give help although pure adherents of Islam are in favour of restricting beggary . A first reason for this is that most West African societies are deeply Islamized and that begging is a characteristic feature of Islamic societies. But a closer look at the traditional structures shows that the ancestral principle of mutual solidarity is also at the basis of most people's attitude. However, the increasing number of beggars and forms of begging have turned the phenomenon into a national concern. Senegalese novelists and film-makers, even Senegalese members of the Parliament often engage in debates about that national plague and what to do about it. This paper analyzes the various motives for begging and giving alms and discusses youth's attitude towards the issue. Its tentative conclusion is that despite the overall acceptance of the phenomenon for religious reasons--a position of principle--there are clear indications of an increasingly critical attitude towards begging .

Expression and Processing of an Arabidopsis 2S Albumin in Transgenic Tobacco.

2S albumin seed storage proteins undergo a complex series of posttranslational proteolytic cleavages. In order to determine if this process is correctly carried out in transgenic plants, the gene AT2S1 encoding an Arabidopsis thaliana 2S albumin isoform has been expressed in transgenic tobacco. Initial experiments using a reporter gene demonstrated that the AT2S1 promoter directs seed specific expression in both transgenic tobacco and Brassica napus plants. The entire AT2S1 gene was then transferred into tobacco plants, where it showed a tissue specific and developmentally regulated expression. Arabidopsis 2S albumin accumulates up to 0.1% of the total high-salt extractable seed protein. Protein sequencing demonstrated that the amino termini of the two Arabidopsis 2S albumin subunits were correctly processed, suggesting that the protease(s) necessary for posttranslational processing of 2S albumin precursors may display common specificities among different dicot plant species. Immunocytochemical studies showed that the Arabidopsis 2S albumin is localized in the protein body matrix of tobacco endosperm and embryo. Correct processing and targeting of the 2S albumin in transgenic plants suggests that modified versions could be expressed, allowing the study of 2S albumin processing and in particular the possible roles of the processed fragments in protein stability and/or targeting.

Stable Accumulation of Modified 2S Albumin Seed Storage Proteins with Higher Methionine Contents in Transgenic Plants.

We present the results of two sets of experiments designed to express high methionine proteins in transgenic seeds in three different plant species. In the first approach, two chimeric genes were constructed in which parts of the Arabidopsis 2S albumin gene 1 (AT2S1) were fused at different positions to a Brazil nut 2S albumin cDNA clone. Brazil nut 2S albumin was found to accumulate stably in transgenic Arabidopsis, Brassica napus, and tobacco seeds. In the second approach, methionine-enriched AT2S1 genes were constructed by deleting sequences encoding a region of the protein which is not highly conserved among 2S albumins of different species and replacing them with methioninerich sequences. Introduction of the modified AT2S1 genes into three different plant species resulted in the accumulation of the methionine-enriched 2S albumins in all three species at levels reaching 1 to 2% of the total high salt-extractable seed protein.

Engineering herbicide resistance in plants by expression of a detoxifying enzyme.

Phosphinothricin (PPT) is a potent inhibitor of glutamine synthetase in plants and is used as a non-selective herbicide. The bar gene which confers resistance in Streptomyces hygroscopicus to bialaphos, a tripeptide containing PPT, encodes a phosphinothricin acetyltransferase (PAT) (see accompanying paper). The bar gene was placed under control of the 35S promoter of the cauliflower mosaic virus and transferred to plant cells using Agrobacterium-mediated transformation. PAT was used as a selectable marker in protoplast co-cultivation. The chimeric bar gene was expressed in tobacco, potato and tomato plants. Transgenic plants showed complete resistance towards high doses of the commercial formulations of phosphinothricin and bialaphos. These data present a successful approach to obtain herbicide-resistant plants by detoxification of the herbicide.