Gene B5 in Cotton Confers High and Broad Resistance to Bacterial Blight and Conditions High Amounts of Sesquiterpenoid Phytoalexins.

Bacterial blight resistance gene B5 has received little attention since it was first described in 1950. A near-isogenic line (NIL) of Gossypium hirsutum cotton, AcB5, was generated in an otherwise bacterial-blight-susceptible 'Acala 44' background. The introgressed locus B5 in AcB5 conferred strong and broad-spectrum resistance to bacterial blight. Segregation patterns of test crosses under Oklahoma field conditions indicated that AcB5 is likely homozygous for resistance at two loci with partial dominance gene action. In controlled-environment conditions, two of the four copies of B5 were required for effective resistance. Contrary to expectations of gene-for-gene theory, AcB5 conferred high resistance toward isogenic strains of Xanthomonas citri subsp. malvacearum carrying cloned avirulence genes avrB4, avrb7, avrBIn, avrB101, and avrB102, respectively, and weaker resistance toward the strain carrying cloned avrb6. The hypothesis that each B gene, in the absence of a polygenic complex, triggers sesquiterpenoid phytoalexin production was tested by measurement of cadalene and lacinilene phytoalexins during resistant responses in five NILs carrying different B genes, four other lines carrying multiple resistance genes, as well as susceptible Ac44E. Phytoalexin production was an obvious, but variable, response in all nine resistant lines. AcB5 accumulated an order of magnitude more of all four phytoalexins than any of the other resistant NILs. Its total levels were comparable to those detected in OK1.2, a highly resistant line that possesses several B genes in a polygenic background.

Pyramiding B genes in cotton achieves broader but not always higher resistance to bacterial blight.

Near-isogenic lines of upland cotton (Gossypium hirsutum) carrying single, race-specific genes B4, BIn, and b7 for resistance to bacterial blight were used to develop a pyramid of lines with all possible combinations of two and three genes to learn whether the pyramid could achieve broad and high resistance approaching that of L. A. Brinkerhoff's exceptional line Im216. Isogenic strains of Xanthomonas axonopodis pv. malvacearum carrying single avirulence (avr) genes were used to identify plants carrying specific resistance (B) genes. Under field conditions in north-central Oklahoma, pyramid lines exhibited broader resistance to individual races and, consequently, higher resistance to a race mixture. It was predicted that lines carrying two or three B genes would also exhibit higher resistance to race 1, which possesses many avr genes. Although some enhancements were observed, they did not approach the level of resistance of Im216. In a growth chamber, bacterial populations attained by race 1 in and on leaves of the pyramid lines decreased significantly with increasing number of B genes in only one of four experiments. The older lines, Im216 and AcHR, exhibited considerably lower bacterial populations than any of the one-, two-, or three-B-gene lines. A spreading collapse of spray-inoculated AcBIn and AcBInb7 leaves appears to be a defense response (conditioned by BIn) that is out of control.

Faecal Escherichia coli as biological indicator of spatial interaction between domestic pigs and wild boar (Sus scrofa) in Corsica.

On the Mediterranean island of Corsica, cohabitation between sympatric domestic pigs and Eurasian wild boar (Sus scrofa) is common and widespread and can facilitate the maintenance and dissemination of several pathogens detrimental for the pig industry or human health. In this study, we monitored a population of free-ranging domestic pigs reared in extensive conditions within a 800-ha property located in Central Corsica which was frequently visited by a sympatric population of wild boar between 2013 and 2015. We used GPS collars to assess evidence of a spatially shared environment. Subsequently, we analysed by PFGE of XbaI-restricted DNA if those populations shared faecal Escherichia coli clones that would indicate contact and compared these results with those collected in a distant (separated by at least 50 km) population of wild boar used as control. Results showed that one of eight wild boars sampled in the study area shed E. coli XbaI clones identical to clones isolated from domestic pig sounders from the farm, while wild boar populations sampled in distant parts of the study area shared no identical clone with the domestic pigs monitored. Interestingly, within the sampled pigs, two identical clones were found in 2013 and in 2015, indicating a long-time persisting colonization type. Although the method of isolation of E. coli and PFGE typing of the isolates requires intensive laboratory work, it is applicable under field conditions to monitor potential infectious contacts. It also provides evidence of exchange of microorganisms between sympatric domestic pigs and wild boar populations.

The ecdysone response enhancer of the Fbp1 gene of Drosophila melanogaster is a direct target for the EcR/USP nuclear receptor.

The transcription of the Drosophila melanogaster Fbp1 gene is induced by the steroid hormone 20-hydroxyecdysone and restricted to the late-third-instar fat body tissue. In a previous study we showed that the -68 to -138 region relative to the transcription start site acts as an ecdysone-dependent third-instar fat body-specific enhancer in a transgenic assay. Here we report that seven nucleoprotein complexes are formed in vitro on this enhancer when a nuclear extract from late-third-instar fat body is used in a gel shift assay. Accurate mapping of the binding sites of the complexes revealed a remarkably symmetrical organization. Using specific antibodies, one of the complexes was identified as a heterodimer consisting of the ecdysone receptor (EcR) and Ultraspiracle (USP) proteins. The binding site of the heterodimer as defined by mutagenesis and methylation interference experiments bears strong sequence similarity to the canonical hsp27 ecdysone response element, including an imperfect palindromic structure. The two elements diverge at three positions in both half-sites, indicating that the structure of an active EcR/USP binding site allows considerable sequence variations. In vivo footprinting experiments using ligation-mediated PCR and wild-type or ecdysteroid-deficient larvae show that occupancy of the Fbp1 EcR/USP binding site and adjacent region is dependent on a high concentration of ecdysteroids. These results provide strong evidence for a direct role of the EcR/USP heterodimer in driving gene expression in response to changes of the ecdysteroid titer during Drosophila larval development.

In vivo functional characterization of an ecdysone response enhancer in the proximal upstream region of the Fbp1 gene of D. melanogaster.

Transcription of the D. melanogaster Fat-body-protein-1 (Fbp1) gene is induced by the steroid hormone 20-hydroxyecdysone and is restricted to the fat body tissue at the end of the third larval instar. The location and functional properties of the Fbp1 cis-acting regulatory sequences contained in the region from -1386 to +80 relative to the transcription start were examined by transformation using hybrid constructs with the Adh or lacZ genes as reporters. Regulatory element(s) required for the full level of transcription of the Fbp1 gene were located between positions -1386 and -138. Sequences between -138 and -68 were able to drive transcription from a heterologous minimal promoter in the fat body of late third instar larvae. Remarkably, these sequences also conferred 20-hydroxyecdysone inducibility and behaved as an enhancer-like element. These results provide the first functional characterization, at the level of the whole organism, using a direct in vivo ecdysone induction assay, of a discrete ecdysone response element.

Incorporation of amino acids by rat liver nucleoli in vitro.

Isolated rat liver nucleoli are shown to incorporate radioactive amino acids into proteins. The characteristics of this nucleolar protein-synthesizine system indicated that the incorporation observed was not due to cytoplasmic or bacterial contamination. The products synthesized by isolated nucleoli have been analyzed by polyacrylamide gel electrophoresis and subsequent autoradiography; this revealed a few radioactive bands suggesting that in vitro only a few proteins are labelled. The results presented are discussed in view of a possible nucleolar protein synthesis.

Carcinogenicity studies with deltamethrin in mice and rats.

The pesticide Deltamethrin, a synthetic pyrethroid, was studied for carcinogenicity in long-term experiments in mice and rats. Mice were given Deltamethrin by gavage in arachis oil at 0, 1, 4 or 8 mg/kg body wt for 2 years. A group of untreated controls was also available. Rats received 0, 3 or 6 mg/kg body wt. Deltamethrin in arachis oil for 2 years. In mice, an increased incidence of lymphomas was observed in the groups receiving 1 and 4 mg/kg body wt., but not in the group treated with 8 mg/kg body wt. Deltamethrin. In rats, an increased incidence of thyroid tumours was noted, but, no clear dose-response relationship was shown. Deltamethrin does not appear to be carcinogenic in mice or rats, but further studies are needed on the group of compounds to which this substance belongs.

Structural features critical to the activity of an ecdysone receptor binding site.

Two ecdysone-response elements from the hsp27 (hsp27 EcRE) and the Fbp1 (D EcRE) genes of Drosophila melanogaster were used as probes in a gel shift assay to investigate the interactions of the ecdysone receptor (EcR) with its cognate DNA response element. The source of EcR was a nuclear extract from the late third-larval instar fat body. The hsp27 and D EcREs share a sequence similarity at 12 positions over a 15bp region including an imperfect palindromic structure consisting of two pentamer half-sites separated by a single intervening nucleotide. We have shown that a short oligonucleotide containing this 11bp imperfect palindrome of the hsp27 EcRE and three flanking bp on each side is an efficient EcR binding site. Mutational analysis confirms that the integrity of both these half-sites as well as their 1bp spacing are critical for binding of the ecdysone receptor. The D EcRE behaved as a much weaker EcR binding site than the hsp27 EcRE but a single bp substitution was sufficient to confer upon it a binding capacity equivalent to that of the hsp27 EcRE. These results have led us to propose the sequence PuG(G/T)T(C/G)A(N)TG(C/A)(C/A)(C/t)Py as a revised version of a previously proposed EcRE consensus sequence.

Inducible nitric oxide synthase, anti-oxidant enzymes and Helicobacter pylori infection in gastritis and gastric precancerous lesions in humans.

Chronic inflammation induced by Helicobacter pylori infection has been associated with an increased risk of stomach cancer. We have analysed 167 stomach biopsies from 99 patients for H. pylori infection and immunohistochemically for the expression of inducible nitric oxide synthase (iNOS), catalase and superoxide dismutases (SODs) as markers of oxidative stress. Biopsies were graded as follows on the basis of histology: normal, superficial gastritis, variable severity of atrophic gastritis with or without intestinal metaplasia, and dysplasia. iNOS was detected in inflammatory cells in all types of gastritis with or without H. pylori infection and independently of its severity. In foveolar cells, iNOS was observed in approximately 25% of all biopsies showing any type of gastritis, but in a markedly higher proportion of dysplastic samples. Catalase and Mn-type SOD in inflammatory cells and catalase in foveolar cells were more frequently observed in marked atrophic gastritis biopsies than in less severe gastritis. Individual differences were found in the expression of these enzymes within groups with the same severity of gastritis. Prolonged oxidative stress in severe gastritis and dysplasia may play an important role in gastric carcinogenesis, through increased damage of DNA and tissue by reactive oxygen and nitrogen species.

Multiple neuroendocrine responses to chronic social stress: interaction between individual characteristics and situational factors.

After four weeks of individual housing, male Wistar rats (selected for high or low spontaneous aggressiveness by multiple round-robin encounters) were housed three per cage and submitted to four weeks of chronic social stress consisting of changing membership in the social groups by daily rotation of the animals among cages every day according to a random permutation procedure. In addition, half the males in each condition were housed with three females. Each environmental condition triggered different neuroendocrine changes. Cohabitation with females increased the hypothalamo-pituitary-adrenocortical axis activity, including enlargement of adrenals and increased circulating corticosterone levels. On the other hand, daily rotation of the rats between different social groups activated part of the sympathetic nervous system, such as increased phenylethanolamine N-methyl transferase (PNMT) activity in the adrenals. The level of aggressiveness, however, had no direct influence but interacted with environmental factors on such neuroendocrine measures as circulating testosterone or plasma renin activity. These results indicate that during chronic stress, there is no single, unique response by the animal, but a highly complex set of neuroendocrine changes, dependent on the interaction between individual characteristics (the level of aggressiveness is an example) and situational factors.

Statistical study of a gamma camera transfer function.

In order to investigate the theoretical resolution of a gamma camera, the position transfer function of the input converters, scintillator and photocathode, has been studied. It is assumed that point scintillations occur in a scintillator at xy0 at a height h above a plane photocathode of sensitivity p per incident photon and that the spatial emission pattern of photoelectrons is known completely. A statistical analysis is given of various methods for determination of the estimator x0 of x0 both for a photocathode of finite and infinite extent. It is shown that the standard deviation sigma of this estimator x0 has a minimum value 2h/(N0p)1/2 where N0p/2 is the total number of photoelectrons emitted by the cathode.

Four near-isogenic lines of cotton with different genes for bacterial blight resistance.

ABSTRACT The development and genetic characterization of four near-isogenic lines (NILs) of cotton (Gossypium hirsutum) is described herein. Each line contains a single, but different, gene for resistance to bacterial blight caused by Xanthomonas campestris pv. malvacearum. The lines were derived using at least six backcrosses to the susceptible recurrent parent 'Acala 44', followed by single plant-progeny row selection for uniformity. The NILs are homozygous for the B(2), B(4), B(In), or b(7) genes and are designated as AcB(2), AcB(4), AcB(In), and Acb(7), respectively. In the 'Acala 44' background, B(2), B(4), and B(In) are partially dominant genes; b(7) is partially recessive. Relative strengths of resistance conferred by those genes toward race 1 of the pathogen were B(4) b(7)>B(In) B(2). B(4), B(In), and b(7) each conferred resistance toward X. campestris pv. malvacearum carrying a single avirulence gene, whereas B(2) was less specific.

[Metalloporphyrin study in experimental carcinology (author's transl)]. / Intérêt d'une métallo-porphyrine en cancérologie expérimentale.

Antitumoral effects and intratumoral concentrations of a metalloporphyrin were studied in mice with solid chemo-induced or transplanted tumors. The synthesis of this molecule was realised both with a stable metal (TPPS4SnCl2) (TPPS4InCl) and a radioactive metal (TPPS4(113)SnCl2) (TPPS4(111)InCl). The metal is introduced into the tetrapyrollic structure to give this molecule very high stability. The effect of the stable metalloporphyrin on tumoral kinetic parameters was analyzed. No tumoral regression was observed during the various experimental procedures. Even though radioactive molecules were found in the tumours, they were also present as high concentrations in the liver, spleen and kidneys, more than 72 hours after injection. Results are compared with those of various authors who used a molecule without metal, levels being measured by fluorescence in various organs and in the tumors. The interest of this metalled molecule in carcinology is discussed in relation to these new results.

[Cardiovascular effects of peptide inhibitors of the renin-substrate reaction in rats with renovascular hypertension. Goldblatt: 2 kidneys--1 clip]. / Effets cardio-vasculaires d'inhibiteurs peptidiques de la réaction rénine-substrat chez le rat atteint d'hypertension réno-vasculaire. Goldblatt: 2 reins--1 clip.

The antihypertensive effects of 2 different peptidic substrate analogs: AG 84-10 AG 85-12 were investigated in renovascular hypertensive (Goldblatt, 2 kidneys--1 clip) Sprague-Dawley male rats. AG 84-10 (Ac-Pro-Phe-His-Leu-Val-Tyr) is similar to Angiotensinogen 6-13 and AG 85-12 (Ac-Ile-His-Pro-Phe-His-Leu) mimics the C-terminal portion of Angiotensin I. 6 weeks after clipping, hemodynamic profiles of these molecules [Heart rate (HR), mean arterial pressure (MAP), filling parameters, peripheral vascular resistances (PR) and cardiac output (CO)] during 90 minutes, were determined in the anesthetized animals. CO was measured using a thermodilution technique. Parallel radio-immunologic dosages of plasma renin activity were performed. Measurements and calculation of previously defined hemodynamic variables, every 10 minutes, demonstrated that: AG 84-10 exerted an early but transient decrease of MAP and PR, an increase of CO without modification of other hemodynamic parameters. AG 85-12 induced a late and durable decrease of MAP and PR with a significant decrease of heart rate, but without modification of CO and other hemodynamic variables. Example: PR mmHg/ml/mn/kg (mean +/- SD): *p less than 0.05 ** p less than 0.01. (Table: see text). The different levels of plasma renin activity were in accordance with hemodynamic data. So, the 2 peptidic substrate analogs elicited antihypertensive effects with a more efficient action of AG 85-12.

Excess sludge production and costs due to phosphorus removal.

Based on data collected from 35 French wastewater treatment plants and on published data, excess sludge production and chemical consumption associated with phosphorus removal is estimated for the three following phosphorus removal processes: chemical precipitation, Enhanced Biological Phosphorus Removal and hybrid process. The influence of wastewater characteristics on excess sludge production are assessed. Chemical costs and costs associated with sludge disposal were calculated and results for the three phosphorus removal processes are compared. The global costs for phosphorus removal are then estimated.