The spatial distribution of fungi on decomposing alder leaves in a freshwater stream

Summary Transects were cut from alder leaves incubated in a freshwater stream and plated as quadrats so that fungal isolates could be mapped by reconstruction of each transect. Initially there was fewer than one aquatic hyphomycete colonist per quadrat, but the mode increased to 6–7 then progressively decreased to <1. Numbers of species of aquatic hyphomycetes per quadrat rose and fell similarly with a maximum mode of 3–4, as did species per transect with a maximum of 11 and a diversity of 16, comprising 6 dominant species and about 10 occasional species. The latter showed no pattern of appearance but the dominant group was established early and persisted in a dynamic equilibrium. Aquatic hyphomycetes were initially randomly distributed but developed progressively into clumped consortia which persisted after peak colonization, declining as leaf degradation became total. Colonies of the most persistent aquatic hyphomycete species were initially discrete,developing into a complex network of overlapping colonies and species, no two of which showed positive association. These complexes broke down to large colonies of a few species and finally to 1–2 small colonies. The pattern of isolates of the 18 genera of other fungi was the reverse of that for aquatic hyphomycetes. Only Cladosporium, Epicoccum and Fusarium were important colonizers. The first two appear to be inhibited by aquatic hyphomycetes, but were found to degrade substrates representative of cell-wall polymers vigorously whereas aquatic hyphomycetes showed varied degradative ability. Leaf transects were examined by S.E.M. and epifluorescent microscopy so that hyphal colonization could be followed at progressive stages of leaf degradation. Bacteria on transects were patchily distributed, the temporal pattern indicating inhibition by aquatic hyphomycetes and colonization of senescent hyphae.     

Delay of airway epithelial wound repair in COPD is associated with airflow obstruction severity

Background

Airway epithelium integrity is essential to maintain its role of mechanical and functional barrier. Recurrent epithelial injuries require a complex mechanism of repair to restore its integrity. In chronic obstructive pulmonary disease (COPD), an abnormal airway epithelial repair may participate in airway remodeling. The objective was to determine if airway epithelial wound repair of airway epithelium is abnormal in COPD.

Methods

Patients scheduled for lung resection were prospectively recruited. Demographic, clinical data and pulmonary function tests results were recorded. Emphysema was visually scored and histological remodeling features were noted. Primary bronchial epithelial cells (BEC) were extracted and cultured for wound closure assay. We determined the mean speed of wound closure (MSWC) and cell proliferation index, matrix metalloprotease (MMP)-2, MMP-9 and cytokines levels in supernatants of BEC 18 hours after cell wounding. In a subset of patients, bronchiolar epithelial cells were also cultured for wound closure assay for MSWC analyze.

Results

13 COPD and 7 non COPD patients were included. The severity of airflow obstruction and the severity of emphysema were associated with a lower MSWC in BEC (p = 0.01, 95% CI [0.15-0.80]; p = 0.04, 95% CI [−0.77;-0.03] respectively). Cell proliferation index was decreased in COPD patients (19 ± 6% in COPD vs 27 ± 3% in non COPD, p = 0.04). The severity of COPD was associated with a lower level of MMP-2 (7.8 ± 2 10⁵ AU in COPD GOLD D vs 12.8 ± 0.13 10⁵ AU in COPD GOLD A, p = 0.04) and a lower level of IL-4 (p = 0.03, 95% CI [0.09;0.87]). Moreover, higher levels of IL-4 and IL-2 were associated with a higher MSWC (p = 0.01, 95% CI [0.17;0.89] and p = 0.02, 95% CI [0.09;0.87] respectively). Clinical characteristics and smoking history were not associated with MSWC, cell proliferation index or MMP and cytokines levels. Finally, we showed an association of the MSWC of bronchial and corresponding bronchiolar epithelial cells obtained from the same patients (p = 0.02, 95% CI [0.12;0.89]).

Conclusion

Our results showed an abnormal bronchial epithelial wound closure process in severe COPD. Further studies are needed to elucidate the contribution and the regulation of this mechanism in the complex pathophysiology of COPD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0151-9) contains supplementary material, which is available to authorized users.     

Pectinases in leaf degradation by aquatic hyphomycetes I: the field study

Summary The colonization-pattern of aquatic Hyphomycetes on five-gram leaf packs of oak and alder submerged in a stream was quantified and compared. There were three series of alder leaves, submerged two weeks apart, and one series of oak. Colonization of leaves by pectolytic bacteria was also measured. There were marked similarities in the colonization of all four series. Total spore counts/g dry wt of leaf rose to a peak followed by a decline. The time taken to peak colonization was slower in oak than in alder, and in alder depended on the level of inoculum in the stream, as did the extent of colonization. Pectolytic bacteria counts followed the pattern of total spore counts, suggesting the exploitation of the same substrates by bacteria and fungi. Temperature and micro-environmental factors influence the overall rate of leaf degradation. Alder I was skeletonized in 10 wks, Alders II and III in 12 wks and oak in 25 wks.The resource was shown to have an upper limit of microbial colonization, and within this unit-community of microbes, there was an association of four dominant species of aquatic Hyphomycetes, together with about ten occasional species. The dominant species are subject to selection from the inoculum available in the stream and the formation and maintenance of the association appears to be the result of competitive interactions between species which results in a dynamic equilibrium. There is a low degree of resource specificity. The species equilibrium is 14 for all series, and species numbers are initially low, rise to a peak, then tend to decline. There is a taxonomic similarity of about 60% between successive stands of all series and between matched stands of alder.     

Disparities of Perceptions and Practices Related to Cervical Cancer Prevention and the Acceptability of HPV Vaccination According to Educational Level in a French Cross-Sectional Survey of 18–65 Years Old Women

Introduction

We aimed to study the relationships between educational level, women''s knowledge about cervical cancer (CC), and acceptance of HPV vaccination for their daughters.

Methods

We analysed data from a quantitative (self-administrated questionnaire) and qualitative (semi-structured interviews) cross-sectional study performed in 2008 among 1,229 French 18–65-year-old women recruited by general practitioners. Women were categorized into three educational level groups: low (LEL: 43.9%), medium (MEL: 33.4%) and high (HEL: 22.6%).

Results

Knowledge about CC and its prevention was lower among LEL women. In the 180 mothers of 14–18-year-old daughters (99 LEL, 54 MEL, 45 HEL), acceptance of HPV vaccine was higher in LEL (60.4%) and MEL (68.6%) than in HEL mothers (46.8%). Among LEL mothers, those who were favourable to HPV vaccination were more likely to be young (OR = 8.44 [2.10–34.00]), to be vaccinated against hepatitis B (OR = 4.59 [1.14–18.52]), to have vaccinated their children against pneumococcus (OR = 3.52 [0.99–12.48]) and to present a history of abnormal Pap smear (OR = 6.71 [0.70–64.01]).

Conclusion

Although LEL women had poorer knowledge about CC and its prevention, they were more likely to accept HPV vaccination than HEL mothers.