Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence

Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants.

A comparative study of the prevalence of domestic violence in women requesting a termination of pregnancy and those attending the antenatal clinic

OBJECTIVE

To compare the prevalence of domestic violence (DV) in women requesting antenatal care (ANC) and termination of pregnancy (TOP) in North East England.

DESIGN

This was a cross-sectional comparative prevalence study using self-administered questionnaires, with women selected as opportunistic samples over a concurrent period.

SETTING

The participants were screened anonymously and confidentially in the ANC and TOP clinics.

SAMPLE

Pregnant women in the first trimester requesting a TOP or ANC.

METHODS

The participants were screened for a history of DV using a modified version of the Abuse Assessment Screening tool.

MAIN OUTCOME MEASURES

Prevalence of DV between ANC and TOP populations, and any differences in the characteristics of the women, such as age, level of education, or marital status. We aimed to determine the reasons for requesting a TOP.

RESULTS

There were 507 respondents, with 233 attending ANC and 274 requesting a TOP. Of the ANC population, 219 completed the questionnaire. In the TOP population, all the questionnaires were fully or partially completed. Women requesting a TOP were six times as likely to suffer physical abuse in the current relationship (5.8 versus 0.9%; χ(2) = 10.2 (2); P < 0.05), and were five times as likely to suffer emotional abuse (9.9 versus 1.8%; χ(2) = 13.6 (2); P < 0.0001), than those attending ANC. Of the 274 women requesting a TOP, only ten mentioned DV as a contributing factor.

CONCLUSIONS

There is a higher prevalence of DV in the TOP population than in the ANC population, but very few women stated that DV influenced their request for a TOP.

Perinatal water intoxication due to excessive oral intake during labour

The increased body water in pregnant women and the birth-related activation of water-sparing systems contribute to a high risk of perinatal water intoxication if the mother drinks too much water during labour. This study reports on four newborn term infants and one mother presenting with life-threatening symptoms due to hyponatraemia from excessive oral intake during labour. Awareness of this diagnosis in the delivery unit is very important, because the clinical picture may mimic that of pre-eclampsia or dehydration.

CONCLUSION

Guidelines are proposed to prevent and treat perinatal water intoxication due to excessive oral intake during labour.

The newborn infant is protected by an innate antimicrobial barrier: peptide antibiotics are present in the skin and vernix caseosa

BACKGROUND

Peptide antibiotics are part of the surface defences against microbial intruders. However, the presence and significance of these innate immune effectors in the skin barrier of the newborn infant have not yet been appreciated. Erythema toxicum neonatorum is an inflammatory skin reaction of unknown aetiology and significance, commonly present in the healthy newborn infant.

OBJECTIVES

As peptide antibiotics are upregulated in inflammatory skin disorders, we hypothesized that this also could be the case in erythema toxicum. We also investigated if the vernix caseosa, a cream-like white substance present on the skin of the infant at birth, might contribute to host defences.

METHODS

The presence of the human antibacterial peptide LL-37 was investigated by immunohistochemistry and confocal imaging of skin biopsies from four 1-day-old infants with an erythema toxicum rash and four matched newborns without the rash. In addition, we analysed the expression of LL-37 and human beta defensin-1, an antibacterial peptide of epithelial origin, by reverse transcriptase-polymerase chain reaction. Finally, we screened for antibacterial components in vernix material obtained from six healthy newborns by inhibition zone assays.

RESULTS

All biopsies from the lesions of erythema toxicum showed a dense, nodular infiltrate with numerous LL-37-expressing cells located in the dermal layer and a clear localization of the peptide within CD15-expressing neutrophils, EG2-expressing eosinophils and CD1a-expressing dendritic cells. LL-37 was also found to be located in CD1a-expressing Langerhans cells and a positive staining for the peptide was seen throughout the whole epidermal layer, both in infants with and without the rash. Skin samples from infants with the rash of erythema toxicum showed a constitutive expression of human beta defensin-1, while the expression of LL-37 seemed to be induced. Furthermore, LL-37 and lysozyme were detected in the protein fractions derived from the vernix caseosa, and these fractions exhibited a clear antibacterial activity.

CONCLUSIONS

Peptide antibiotics are present in the vernix caseosa and in the skin of the healthy newborn infant, indicating effective innate immune protection already during fetal and neonatal life.

Normal female anal sphincter: difficulties in interpretation explained

PURPOSE

Our aims were to quantify the nature, characteristics, and frequency of variations in female anal sphincter anatomy.

METHODS

Nulliparous patients from the antenatal clinic and healthy volunteers of both genders were studied. Sphincter length was determined by the position of the puborectalis sling. Defects in the external anal sphincter were defined at each level and recorded in degrees. Cylindric longitudinal images of the endoanal scans were created by a three-dimensional-representation software package. Manometry was performed by a pull-through technique.

RESULTS

Fifty-seven nulliparous patients and 18 healthy volunteers were included in the study. The mean age was 39 years for males and 28.35 years for females. There was no significant difference in overall sphincter length or in the internal anal sphincter length as a percentage of overall sphincter length between genders. All nine males had a complete ring of external anal sphincter along the full sphincter length. In the external anal sphincter below the level of the puborectalis sling, a natural gap occurred in 43 nulliparous (75 percent) and all 9 female volunteers. The greater the size of the defect, the greater its extent (mean 1.33 cm for >90 degrees and 1.16 cm for <90 degrees; chi-squared P = 0.008, eight degrees of freedom). Manometry provided confirmatory evidence of the gaps seen. Anal manometry was analyzed by Mann-Whitney U test for continuous nonparametric data and t-test for comparison between genders.

CONCLUSION

The female sphincter has a variable natural defect occurring along its anterior length. This makes interpretation of the isolated endoanal ultrasound difficult and explains previous overreporting of obstetric sphincter defects.

The Hantaan virus glycoprotein precursor is cleaved at the conserved pentapeptide WAASA

The medium segment of the tripartite negative-stranded RNA genome of hantaviruses encodes for the predicted glycoprotein precursor GPC. We have demonstrated here the expression of the glycoprotein precursor of Hantaan virus following transfection of mammalian cells. The cleavage of the precursor into the glycoproteins G1 and G2 followed the rules for signal peptides and seemed to occur directly at the pentapeptide motif "WAASA." Our data indicate that the signal peptidase complex is responsible for the proteolytic processing of the precursor GPC of Hantaan virus. The comparison of this region of the glycoprotein precursor, including the absolutely conserved WAASA motif, suggests a similar cleavage event for all hantavirus glycoproteins.

Long-term sexual co-habitation offers no protection from hypertensive disease of pregnancy

Long-term sexual co-habitation and previous pregnancies are thought to protect against the development of hypertensive disease of pregnancy. In order to test the hypothesis that pregnancies conceived after prolonged exposure to the partner's spermatozoa have reduced rates of hypertensive disease this study examined the outcomes of pregnancies of women who conceived by donor insemination as compared with women who conceived after IVF with partner's spermatozoa. This was a retrospective cohort study of 218 women attending an IVF clinic, 45 of whom conceived by donor insemination and 173 of whom conceived by partner's spermatozoa. Cases were identified from the IVF unit and data were extracted from patients' notes by blinded observers. Results showed no difference between the groups, with 22% of women who conceived with donor spermatozoa and 24% who conceived with partner spermatozoa developing some form of hypertensive disease of pregnancy. Insemination by partner's spermatozoa was not associated with a reduction of hypertensive disease and neither was donor spermatozoa associated with an increased incidence.

Use of videotapes for viewing at home to inform choice in Down syndrome screening: a randomised controlled trial

A randomised trial was carried out to assess the effect of a Down syndrome screening video on test uptake, knowledge and psychological stress. A total of 2000 women referred for antenatal care were allocated to two equal groups: one to be sent a video to their home, before their hospital booking visit, and a control group. All women also received screening information in the form of a leaflet before booking and from a midwife at booking. The video had no effect on the screening uptake rate: 638/993 (64.2%) and 652/1007 (64.7%) in the video and control groups, respectively. Women were requested to return the video for reuse in other pregnancies and 612 (62%) did so. A subset of 1200 women were selected to be posted at 17-19 weeks' gestation a self-completed questionnaire to assess the psychological endpoints. Knowledge of screening was increased in the video group with a mean score of 7.3 compared with 6.7 in the controls, a statistically significant difference (t=3.24, p=0.0005). There were no significant differences between the groups in specific worries about abnormalities in the baby, and general anxiety. We conclude that a video can increase knowledge without affecting the uptake of the test, or psychological stress.

Cloning of the putative tumour suppressor gene for hereditary multiple exostoses (EXT1)

Hereditary multiple exostoses is an autosomal dominant disorder that is characterized by short stature and multiple, benign bone tumours. In a majority of families, the genetic defect (EXT1) is linked to the Langer-Giedion syndrome chromosomal region in 8q24.1. From this region we have cloned and characterized a cDNA which spans chromosomal breakpoints previously identified in two multiple exostoses patients. Furthermore, the gene harbours frameshift mutations in affected members of two EXT1 families. The cDNA has a coding region of 2,238 bp with no apparent homology to other known gene sequences and thus its function remains elusive. However, recent studies in sporadic and exostosis-derived chondrosarcomas suggest that the 8q24.1-encoded EXT1 gene may have tumour suppressor function.