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Boron deficiency in the soil is commonly found throughout the country, mainly in cerrado soils, making it extremely necessary to fertilize such a micronutrient. Therefore, this study aimed to evaluate the availability of boron in clay and sandy soils with different sources of borated fertilizers in soybean cultivation in the 2018/19 soybean harvest. The availability of boron was evaluated by the method with hot water extraction in a soil sample in different soil layers and at a different time of collection. The experiment was assembled in randomized blocks (DBC), with 5 treatments and 4 replications, as follows: split boric acid: twice, total boric acid: one application of the integral dose, Granulex ®️, Produbor®️ and control treatment Granulex provided higher B content in the soil in the 1st collection, in the 10-20 cm layer in cl In sandy soil, the different sources did not defer under the availability of B at all depths and collections. In general, clayey soils retain B more when compared to sandy soils

Surmmary Forty-eight human isolates of Yersinia enterocolitica of biotype 4, serotype 03 from various parts of the world were examined for susceptibility to 13 β-lactam agents. The intracellular β-lactamases of each of the 48 strains were examined. Isolates from Europe, Asia and Brazil (phage type VIII) or South Africa and Hungary (phage type IXa) produced both enzyme A and enzyme B, whereas isolates from New Zealand and Australia (phage type IXb) lacked the cephalosporinase enzyme B. Among the seven strains isolated in Canada belonging to phage type IXb, three strains expressed only enzyme A (group I) whereas the other four strains produced both enzymes A and B (group II). The high susceptibility to the combination of amoxycillin and clavulanate observed in one subtype was explained by the absence of the cephalosporinase enzyme B. A simple disk diffusion test with this antibiotic combination was shown to be effective in the detection of enzyme B in Y. enterocolitica 4/O3.

The irp2 gene codes for a 190 kDa protein (HMWP2) synthesized when highly pathogenic Yersinia are grown under conditions of iron starvation. In this work, the presence of irp2 in strains of Y. pestis isolated from different hosts during several plague outbreaks in the foci of Northeast Brazil was studied. For this purpose, 53 strains were spotted onto nylon filters and their DNA was hybridized with the A13 probe which is a 1 kb fragment of the irp2 coding sequence. All strains except two hybridized with the probe. However, when the initial stock culture of these two strains were analyzed, they both proved to be positive with the A13 probe, indicating that the locus was lost after subculture in vitro but was always present in vivo. To examine the degree of conservation of the chromosomal fragment carrying irp2 among Brazilian strains, the hybridization profiles of 15 strains from different outbreaks, different hosts and different foci were compared. The hybridization profiles of these strains were all identical when their DNA was digested with either EcoRI, EcoRV or AvaII, indicating that the restriction sites surrounding the irp2 locus are very well conserved among Northeast Brazilian strains of Y. pestis. Altogether, these results suggest that the irp2 chromosomal region should be of prime importance for the bacteria during their multiplication in the host.

Amoxicillin, cefotaxime, ceftriaxone, gentamicin, doxycycline, and ofloxacin were active in vitro, like the reference drug streptomycin, against the virulent strain Yersinia pestis 6/69M. The comparative efficacies of these drugs in vivo were evaluated in a standardized and reproducible mouse model of systemic infection. Each antibiotic was injected intravenously once, at 24 h postinfection, and then repeatedly during 48 h. In vivo results were measured by counting the viable bacteria recovered from the whole spleens of mice sacrificed at selected times. All the drugs were manifestly successful; ceftriaxone, ofloxacine, and the reference drug were the most effective. Therefore, gentamicin and doxycycline could be used, depending on the clinical forms of the Y. pestis infection. Further investigations on beta-lactams, especially those used in the present study, could be carried out to confirm or not confirm their activities against Y. pestis. Ofloxacin appeared to be as active and to perform as rapidly as streptomycin in the treatment of murine Y. pestis infection, which is in agreement with the previous successes obtained with the use of fluoroquinolones in the treatment of murine infections caused by other pathogenic yersiniae.

Multiple copies of several classes of insertion sequences (IS) are found in the genome of Yersinia pestis, the causative agent of bubonic and pneumonic plague. We used the genetic instability generated by these IS to develop a method (designated 3IS-RFLP) based on the restriction fragment length polymorphism of the IS100, IS285 and IS1541 elements for studying Y. pestis strains of worldwide origin. We show that 31S-RFLP is a powerful tool to group Y. pestis isolates according to their geographical origin, and therefore that this method may be valuable for investigating the origin of new or re-emerging plague foci or for addressing forensic issues.

The genus Yersinia is composed of 11 species, three of which are pathogenic for human beings: Y. enterocolitica, Y. pseudotuberculosis, and Y. pestis. The former two are widely spread in temperate countries; they are transmitted by the fecal-oral route and cause digestive symptoms, usually of moderate intensity. In contrast, Y. pestis predominates in tropical and subtropical areas; it is transmitted mainly by flea bites and causes an extremely severe disease called plague.

A pathogenicity island present only in highly pathogenic strains of Yersinia (Y. enterocolitica 1B, Y. pseudotuberculosis I and Y. pestis) has been identified on the chromosome of Yersinia spp. and has been designated High-Pathogenicity Island (HPI). The Yersinia HPI carries a cluster of genes involved in the biosynthesis, transport and regulation of the siderophore yersiniabactin. The major function of this island is thus to acquire iron molecules essential for in vivo bacterial growth and dissemination. The presence of an integrase gene and att sites homologous to those of phage P4, together with a G + C content much higher than the chromosomal background, suggests that the HPI is of foreign origin and has been acquired by chromosomal integration of a phage. The HPI can excise from the chromosome of Y. pseudotuberculosis and is found inserted into any of the three copies of the asn tRNA loci present in this species. A unique characteristic of the HPI is its wide distribution in various enterobacteria. Although first identified in Yersinia spp., it has subsequently been detected in other genera such as E. coli, Klebsiella and Citrobacter.

The aetiology of plague was first discovered during the third pandemic of the disease occurring in Hong Kong in 1894. After Alexandre Yersin had identified the causal agent (Y. Pestis), Paul-Louis Simond proved the flea's role as vector. These discoveries were of prime importance for the subsequent development of efficient means for fighting plague as well as for preventive and curative treatments and vaccines. Vaccination brought about a sharp decrease in plague mortality and morbidity. However, the disease has never been eradicated. It is still prevalent in various Asian, African and American countries and is among the re-emerging diseases at the present time. The genetic basis of transmission mechanisms and pathogenicity of the bacillus are only beginning to be understood. We now know that the attenuation of the EV76 strain used by Girard and Robic as an anti-plague vaccine in Madagascar is due to the spontaneous excision of a large chromosomal DNA fragment of 102 kb, a part of which contains a group of genes implicated in the pathogenicity and appropriately called high pathogenicity island. These mechanisms of flea bacillus transmission are also beginning to be known. Two bacterial loci participating in the blocking of the ectoparasite's proventriculus have been identified. One is situated next to the high pathogenicity island on the unstable 102 kb chromosomal fragment, the other--on the large 95 kb plasmid specific to Y. pestis. The molecular basis of the bacillus' acquisition of multi-resistance to antibiotics have likewise recently been characterised. However, although Y. pestis is one of the most pathogenic micro-organisms of the bacterial world, the mechanisms responsible for this high level of pathogenecity have still not been identified. This is well worth noting, since a certain number of genes acting as pathogenicity factors in other species are present but altered in Y. pestis. Plague still withholds many secrets.

The gene (ystB) encoding the novel subtype of the heat-stable enterotoxin (Y-STb) was cloned from the chromosome of a clinical isolate of Yersinia enterocolitica 84-50 (serotype O:5, biotype 1A) and the nucleotide sequence was determined. The ystB contained 216 base pairs that encoded a protein of 71 amino acid residues. The C-terminal 30 residues of the precursor protein exactly corresponded to the amino acid sequence of the Y-STb toxin, purified from the culture supernatant of the wild strain. Homology search revealed that there are 76.9% nucleotide sequence similarity between ystB and the Yersinia kristensenii ST gene, and 73.5% with the Y. enterocolitica prototype sequence of yst (ystA). When tested with the PCR generated ystB specific probe, 36 of 304 Y. enterocolitica strains from 18 countries hybridized with the probe. All the ystB probe positive strains belonged to biotype 1A and mostly to the so-called non-pathogenic serotype O:5, O:6, O:7,8 O:7,13 and O:10, while ystA was predominantly found among the pathogenic serotypes (78.5%). Out of 36 ystB gene positive strains, 18 were clinical origin from six countries, which were also positive in the suckling mice assay suggesting that ystB may play an important role in the pathogenesis, and the so-called non-pathogenic serotypes could be virulent for human.

The test classically used for the serological diagnosis of yersiniosis is based on the technique of agglutination of killed bacteria. The sensitivity of this technique is low and numerous cross reactions are observed. The aim of this work was to develop a new serological test based on the ELISA method and to compare the results obtained by this method and by agglutination.The antigens used for the ELISA test were the virulence plasmid-encoded proteins present in all pathogenic Yersinia and specific for this bacterial genera. The background of this technique was determined using 30 normal human sera. Validation of the ELISA method was performed with human sera negative (23) or positive (72) by the agglutination technique. The sensitivity of the ELISA test was compared with that of agglutination using 10 patients' sera which remained negative by the agglutination test despite the isolation of a pathogenic Yersinia. Finally, the ELISA specificity was determined with the sera of patients suffering from tuberculosis (20), typhoid fever (6), suspected or confirmed brucellosis (5) and suspected yersiniosis but having a positive Wright reaction (13).We show here that, in addition to the advantages inherent in the ELISA technique, this test is more sensitive and specific than the agglutination test. Furthermore, the ELISA test can be used for all pathogenic Yersinia, whatever their serotype and biotype.The use of the ELISA test should significantly improve the serodiagnosis of yersiniosis.

The study has examined how the plague bacillus expresses genes of two high-molecular weight (190 and 240 kD) iron-regulated membrane proteins (HMWP). The latter were purified and assayed for their immunobiological properties in vitro and in vivo. DNA-probing (at E.Carniel's Laboratory, Pasteur Institute, Paris) has indicated that Yersinia pestis strains having genes that code for HMWP synthesis circulate in the natural foci of plague which are situated in the former USSR. The use of HMWP in combination with live plague vaccine EV was found to greatly enhance its immunogenicity.

Iron starvation induces the synthesis of two high molecular weight proteins (HMWP1 and 2) in Yersinia. The presence of the irp2 gene coding for the HMWP2 was investigated in 170 Yersinia strains. This gene was absent from all avirulent or weakly pathogenic species and was restricted to highly pathogenic strains. One hundred percent of the potentially highly pathogenic Yersinia enterocolitica biotype 1B harbored irp2 but surprisingly, 70.4% of the Yersinia pseudotuberculosis tested lacked the gene. Only serotypes I and III of Y. pseudotuberculosis harbored the locus, however, synthesis of HMWPs was detected uniquely in the former. In Yersinia pestis, overall 55.3% of the strains tested had the gene, with an uneven distribution among Orientalis (65.2%), Antiqua (66.6%) and Medievalis (0%) geographic variants. Except for one Y. pestis strain, the irp2 restriction profiles were identical for all strains of Y. pestis and Y. pseudotuberculosis tested. All Y. enterocolitica 1B displayed the same irp2 pattern, different from that of the other two species. In vitro spontaneous deletion of irp2 was not obtained in Y. enterocolitica 1B but was observed in both Y. pseudotuberculosis and Y. pestis. Repeated subcultures of Y. pestis increased progressively the proportion of irp2-deleted colonies, yielding an almost pure irp2-deleted strain after 16 subcultures. A clear correlation was established between the presence of irp2 and the level of virulence of Y. pseudotuberculosis and Y. pestis.

Under iron-starvation, the highly pathogenic Yersinia synthesize several iron-regulated proteins including two high-molecular-weight polypeptides (HMWP1 and HMWP2). From the chromosome of Yersinia enterocolitica serovar O:8 (strain Ye 8081), the genes coding for the HMWP2 (irp2) and its promoter were cloned into plasmid pUC18 (pIR2) and used as a probe. We show here that the irp2 gene is present only in the highly pathogenic strains and that its promoter is iron-regulated in Escherichia coli. After introduction of the pIR2 plasmid into a fur mutant of E. coli, both the iron-starved and the iron-replete bacteria expressed the HMWP2. Repressibility of irp2 by iron was restored by introduction of a plasmid carrying the fur gene. These results demonstrate that the irp2 promoter is controlled by the Fur repressor in E. coli. Mutagenesis of the chromosomal irp2 gene of Yersinia pseudotuberculosis was obtained by homologous recombination with a 1 kb fragment of this gene cloned on the suicide plasmid pJM703.1. Inactivation of irp2 resulted in the non-expression of both HMWPs, while introduction of plasmid pIR2 into the mutant strain led to the synthesis of the HMWP2 only. Therefore, it is probable that the genes coding for the HMWPs constitute an operon where irp2 is upstream of irp1. When comparing the virulence of the wild-type strain and of its irp2 mutant derivative, we found that the 50% lethality (LD50) for mice of the mutant strain was increased, whatever the route of infection, but more markedly when injected parenterally. Accordingly, these data demonstrate that a mutation in the irp2 gene alters the pathogenicity of Y. pseudotuberculosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Field inversion gel electrophoresis (FIGE) and contour-clamped homogeneous field (CHEF) electrophoresis were used to analyse the chromosome of Yersinia ruckeri. The 8 base-pair recognition endonucleases, NotI and SfiI, generated less than 47 DNA fragments whose size and distribution were appropriate for pulsed field separation. Each isolate displayed a characteristic restriction pattern, with about 20% of bands in common. Depending on the strain used, the estimated genome size for this bacterial fish pathogen ranged from 4460 to 4770 kilobase pairs.

Resume A l'occasion d'un cas recent de choc septique survenu au cours d'une transfusion de concentre globulaire contamine par Yersinia enterocolitica , les auteurs ont rassemble 18 autres observations de ce syndrome mortel dans 70 % des cas. Leur analyse montre que la contamination resulte d'une bacteriemie chez des donneurs, porteurs sains de Y. enterocolitica dont la multiplication dans les poches de concentres globulaires est favorisee par leur conservation a + 4°C.

Under iron-starvation conditions, the different Yersinia species expressed various iron-regulated proteins. Among them, two high-molecular-weight outer membrane proteins were synthesized in high-virulence-phenotype Y. pestis, Y. pseudotuberculosis, and Y. enterocolitica serovars O:8 and O:Tacoma but were present neither in low-virulence phenotype Y. enterocolitica serovars O:3 and O:9 nor in avirulent Y. frederiksenii, Y. kristensenii, Y. intermedia, and Y. enterocolitica serovar O:39. Thus, the degree of virulence correlates with the presence of the two high-molecular-weight proteins in Yersinia species.

A genomic library containing DNA fragments of 0.5 to 2 kilobase pairs in length from Yersinia enterocolitica serovar O:8 was constructed in a bacteriophage lambda gt11 expression vector. Mouse antibodies specific for the iron-regulated high-molecular-weight proteins (HMWPs) were used to screen the library. Two positive clones of 1 and 0.5 kilobase pairs, designated A13 and D7, respectively, were detected and isolated. They coded for beta-galactosidase fusion proteins of 151,000 and 138,000 daltons (Da). Antibodies affinity purified on the two recombinant lambda gt11 vectors specifically recognized the smaller HMWP (190,000 Da) and not the larger (240,000 Da). The two cloned DNA fragments were used to construct recombinant amplification plasmid pUC13 and to obtain large amounts of purified A13 and D7 inserts. Southern hybridizations performed with the inserts used as probes revealed that: (i) the two cloned DNA fragments overlap; (ii) only one gene hybridizes with the A13 and D7 inserts; (iii) the gene coding for the HMWP is conserved among all highly pathogenic Yersinia species studied; (iv) this gene is missing in the low-virulence and nonvirulent strains; and (v) transcription of the HMWP gene is induced by iron starvation.

In a search for Yersinia infection in Bangladesh, one isolate of Y. enterocolitica serotype 0:3 was obtained from stools of 1,450 children with fever and diarrhea and one of Y. enterocolitica serotype 0:8 was recovered from intestinal contents of 80 fatal diarrheal cases during postmortem examination. These results suggest that Yersinia infection is an infrequent cause of tropical diarrhea.

International audience; Identification of microbial pathogens in clinical specimens is still performed by phenotypic methods that are often slow and cumbersome, despite the availability of more comprehensive genotyping technologies. We present an approach based on whole-genome amplification and resequencing microarrays for unbiased pathogen detection. This 10 h process identifies a broad spectrum of bacterial and viral species and predicts antibiotic resistance and pathogenicity and virulence profiles. We successfully identify a variety of bacteria and viruses, both in isolation and in complex mixtures, and the high specificity of the microarray distinguishes between different pathogens that cause diseases with overlapping symptoms. The resequencing approach also allows identification of organisms whose sequences are not tiled on the array, greatly expanding the repertoire of identifiable organisms and their variants. We identify organisms by hybridization of their DNA in as little as 1-4 h. Using this method, we identified Monkeypox virus and drug-resistant Staphylococcus aureus in a skin lesion taken from a child suspected of an orthopoxvirus infection, despite poor transport conditions of the sample, and a vast excess of human DNA. Our results suggest this technology could be applied in a clinical setting to test for numerous pathogens in a rapid, sensitive and unbiased manner.