Pertussis toxin, a protein composed of five different subunits (S1, S2, S3, S4, and S5), is the major virulence factor of Bordetela pertussis. We have cloned and sequenced a DNA fragment of 4.7 kilobases that contains the genes coding for the 'five subunits. The genes are clustered within 3.2 kilobases in the following order: S1, S2, SA, S5, and S3. A sequence closely resembling Escherichia coli promoters is found only before the S1 gene, and a possible termination signal is present at the end of the S3 gene, which suggests that the pertussis toxin genes are organized in a single operon. A possible Shine-Dalgarno sequence is present before the S1 gene but not before the other four genes that 8-12 nucleotides upstream from the ATG codon show a new consensus sequence, 5'TCC(T)GG3', possibly involved in the regulation'of translation. We have also found sequence homology between the S2 and S3 genes and their protein products indicating that gene duplication played a major role in the evolution of pertussis toxin. (Fig. 2), they have a different mobility in NaDodSO4/PAGE. Note also that S5 is stained rather poorly and although its deduced molecular weight is smaller than that of S4 (Fig. 2) under reducing conditions, it migrates more slowly than S4.

Immunization with chemically detoxified pertussis toxin can prevent severe whooping cough with an efficacy similar to that of the cellular pertussis vaccine, which normally gives unwanted side effects. To avoid the reversion to toxicity and the loss of immunogenicity that may follow chemical treatment of pertussis toxin, inactive toxins were constructed by genetic manipulation. A number of genetically engineered alleles of the pertussis toxin genes, constructed by replacing either one or two key amino acids within the enzymatically active S1 subunit, were introduced into the chromosome of strains of Bordetella pertussis, B. parapertussis, and B. bronchiseptica. These strains produce mutant pertussis toxin molecules that are nontoxic and immunogenic and that protect mice from the intracerebral challenge with virulent Bordetella pertussis. Such molecules are ideal for the development of new and safer vaccines against whooping cough.

The present research aimed at studying the psychometric properties of the Mental Health Continuum–Short Form (MHC–SF; Keyes, 2005) in a sample of 1,300 Argentinean adults (50% males; 50% females). Their mean age was 40.28 years old (SD = 13.59). The MHC–SF is a 14 item test that assesses three components (i.e., emotional, social, and psychological) of well-being. Convergent and divergent evidence of construct validity was assessed by conducting confirmatory factor analysis, cross-validation, factorial invariance, and correlations with external criteria. Internal consistency was studied using Cronbach’s alphas. Results indicated an adequate fit of a three-dimensional model. This structure was also confirmed, and was invariant throughout sex and age. The emotional well-being scores converged with life satisfaction and positive affect measures; the psychological well-being scale had a positive association with the presence of meaning in life; and the social well-being scores showed a positive and strong correlation with an external measure of well-being. Also, all scores were negatively associated with negative affect, search of meaning in life, and presence of depression symptoms. Internal consistency was .89 for the MHC–SF. Furthermore, the findings supported the two - continua model of mental health.

Pertussis toxin, a protein composed of five different subunits, is responsible for the pathogenicity of Bordetella pertussis and is the main component of a new vaccine against whooping cough. The genes coding for the five subunits, recently cloned and sequenced, are organized as an operon. We approached the problem of expression of the five genes in Escherichia coli and, although we obtained high levels of transcription of the native pertussis toxin genes, the amount of proteins produced was very low or undetectable. To obtain suitable expression of each of the five subunits, we fused their genes to the gene coding for the DNA polymerase of MS2 in the expression vector pEx31. A total of 5 to 30 mg of purified fusion proteins could be obtained from 1 liter of culture. The purified fusion proteins were used to immunize rabbits to obtain sera against each of the five subunits. These sera, although able to recognize the toxin in an enzyme-linked immunosorbent assay and the corresponding subunits in Western blots, were not able to protect CHO cells from the action of pertussis toxin. Mice immunized with the five subunits were not protected from an intracerebral challenge with B. pertussis. Subunits S2 and S3, which are 67% homologous, were shown to cross-react immunologically. The fused subunit S1 was able to ADP-ribosylate transducin as efficiently as the native pertussis toxin.

Despite mass vaccination against diphtheria, many people have antibody titers below the protective level of 0.01 IU per milliliter. A recent outbreak of diphtheria in Sweden caused 17 clinical cases of diphtheria in the city of Göteborg; three of the patients died. A satellite outbreak occurred in Stockholm after a few months' delay. Using a new genetic probe, we analyzed 36 strains of Corynebacterium diphtheriae isolated in Sweden and Denmark during the period 1976 to 1986. Although the 36 strains can be classified in 17 different groups of C. diphtheriae (several of them containing toxigenic strains), all the clinical and fatal cases of diphtheria were caused by isolates from the same group, strongly suggesting that the outbreak in Sweden was caused by a single strain that possibly had a virulence factor separate from toxigenicity. This strain may have been imported into Sweden from Denmark, since it was isolated for the first time in Copenhagen in 1983, before the outbreak in Sweden.

This study aimed to identify the motives for social media sites use in the general population and determine what personality traits (normal and maladaptive) predict different motives for social media sites use. Another objective was to analyze which motives for SMSs use are related to well-being. The sample consisted of 420 subjects (211 men, 209 women), mean age 40.29 years ( SD =  14.93). Data were gathered using the Big Five Inventory, the Personality Inventory for DSM-5-Brief Form -Adult, the Mental Health Continuum-Short Form, and a scale designed ad hoc to evaluate the motives for social media sites use. The results showed that the most frequent motives were Personal relationship maintenance/Search for information, Pastime/Exhibitionism, and Search for companionship. In addition, it was found that normal and, especially, maladaptive personality traits increased the explained variance for the three motives for social media sites use, beyond age and gender. Predictors of relationship initiation and pastime/exhibitionism motives were related to more negative features (e.g., antagonism and disinhibition) than predictors of personal relationship maintenance/search for information. Finally, personal relationship maintenance/search for information was positively related to all the components of well-being, while the other motives for social media sites use were negatively associated with well-being.

The segment of DNA which is inserted within the tox gene of bacteriophage gamma and is responsible for its Tox-phenotype was found to be present and repeated approximately 30 times in the chromosome of Corynebacterium diphtheriae Belfanti 1030. Other C. diphtheriae strains contained a variable number of copies (1 to 25) of the same element. Sequence analysis showed that this repeated and interspersed DNA element was flanked by 9-base-pair direct repeats and that the 5' and 3' ends of the insertion contained sequences forming an imperfect inverted repeat. Therefore, the DNA segment here described has most of the typical structural features of a bacterial insertion sequence element. We show that different C. diphtheriae isolates derived from the same outbreak of diphtheria have an identical genomic distribution of this DNA element and that such DNA can be useful for epidemiological studies.

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