Microbial population dynamics on Golden Delicious apples from bud to harvest and effect of fungicide applications

The microbial population dynamics on apples cv. Golden Delicious were analysed every 15 days between bud and harvest in a fully replicated experiment in northern Spain in 1994 and 1995. The total microbial populations varied with developmental stage, and with prevailing climatic conditions. The predominant mycroflora were the filamentous fungi Cladosporium and Alternaria spp. and white and pink yeasts. Other genera isolated included mainly species of Epicoccum, Fusarium and Acremonium. However, the most important post-harvest pathogens Penicillium expansum and Botrytis cinerea were seldom isolated from ripening apples. Maximum total filamentous fungal populations occurred after fruit set and during early ripening [2 × 10⁴cfu (colony-forming units) g^-1 approximately] while those of bacteria were maximum at bud stage (3.5 × 10⁵and 3.0 × 10⁴ cfu g^-1 in 1994 and 1995 respectively). White yeasts were more numerous than pink yeasts. Endophytic infection of apple buds by Alternaria spp., responsible for core rot, was found in almost all bud tissue. By contrast, Cladosporium spp. were initially isolated later from 12.5–50% of tissue samples during blooming and fruit set. The impact of a four-spray fungicide regime during apple development significantly decreased the total filamentous fungal populations in both years, and that of Cladosporium spp. in 1994. However, bacterial populations were often higher on apples from fungicide-treated plots. Fungicide sprays decreased populations of Cladosporium, Alternaria and white yeasts for a maximum of up to 15–30 days after application. Fungicide application had little effect on endophytic infection of apples by Alternaria spp. between bud and harvest.     

Characterization of phytoplankton assemblages in a tropical coastal environment using Kohonen self‐organizing map

This study was aimed at understanding the main abiotic environmental factors controlling the distribution patterns of abundance and composition of phytoplankton (size less than 10 μm) assemblages in the coastal waters of south‐eastern Côte d'Ivoire. Data were collected during two cruises, in January (low‐water period) and October (high‐water period) of 2014. A total of 67 species were identified and assigned to Bacillariophyceae (49%), Cyanophyceae (21%), Chlorophyceae (13%), Euglenophyceae (10%), Dinophyceae (4%) and Chrysophyceae (3%). Three biotic zones (I, IIA and IIB) were distinguishable on a Kohonen self‐organizing map after an unsupervised learning process. The diatom genera Eunotia sp., Navicula sp. and Actinoptychus senarius are significantly associated with I, IIA and IIB biotic zones, respectively. A clear seasonal cum salinity trend was apparent in phytoplankton distribution patterns. Turbidity and nitrate levels were the main abiotic factors controlling phytoplankton distribution in I, the upland tidal regions of the lagoon. In regions along the lagoon–sea continuum, phosphate and turbidity exert the most control during the low‐water season (IIA), while total dissolved solids control phytoplankton distribution during the high‐water season (IIB). These are climate‐sensitive parameters whose concentrations depend on prevailing hydroclimatic processes. Therefore, seasonality can have important consequences on phytoplankton community and inadvertently the productivity of these systems.     

Changes in the composition of British butterfly assemblages over two decades

Changes in the abundance and distribution of individual species have been widely documented in Britain and other countries in recent decades, but little has been done to determine changes in community composition over broad geographic areas. Here, we studied species turnover in 51 butterfly assemblages in Britain since 1976, examining extinction and colonisation events together with variation in the abundances of the species. We showed that the species turnover that occurred over 20 years in Britain was associated with colonisation and extinction events and also with variability in the abundance of the species. These changes in community composition differed according to the habitat requirements of the species and their previous distributions, being more evident for habitat specialists and for southerly distributed species. Colonising species often became abundant components of the communities they joined, although this was more evident for generalist than for specialist species. The abundance of species following their arrival, increased with time since colonisation. Species turnover associated with southerly species expanding northwards is consistent with being a response to climate change. The results suggest that climate- and habitat-driven changes in the identity and abundance of species within communities are widespread, and probably ubiquitous. Similar changes are likely to be occurring in other groups of organisms that are similarly undertaking major range shifts associated with climate change.     

The carriage population of Staphylococcus aureus from Mali is composed of a combination of pandemic clones and the divergent Panton-Valentine leukocidin-positive genotype ST152

Staphylococcus aureus is an important human pathogen, but it appears more commonly in asymptomatic colonization of the nasopharynx than in cases of invasive disease. Evidence concerning the global population structure of S. aureus is limited by the overrepresentation in the multilocus sequence testing database of disease isolates recovered from Western Europe, the Americas, Australia, and Japan. We address this by presenting data from the S. aureus carriage population in Mali, the first detailed characterization of asymptomatic carriage from an African population. These data confirm the pandemic spread of many of the common S. aureus clones in the carriage population. We also note the high frequency (approximately 24%) of a single divergent genotype, sequence type 152 (ST152), which has not previously been recovered from nasal carriage isolates but corresponds to a sporadic Panton-Valentine leukocidin (PVL)-positive, community-acquired methicillin-resistant S. aureus clone noted mostly in Central Europe. We show that 100% of the ST152 isolates recovered from nasal carriage samples in Mali are PVL positive and discuss implications relating to the emergence and spread of this virulent genotype.     

Comparison of macrofauna communities in sediments of the beds of vertical flow constructed wetlands planted with Panicum maximum (Jacq.) treating domestic wastewater

To improve our understanding of the ecological functioning of constructed wetlands, the macrofauna structure in the sediments of a constructed wetland planted with Panicum maximum treating domestic wastewater was studied. Two beds were planted with young P. maximum and two unplanted beds were used as controls. After 150 days of wastewater treatment on the beds, macrofauna was collected by taking five cores of sediment samples at the corners and the centre of each bed following three layers in the vertical profile. Globally, the planted beds removed COD, NH₄⁺, and PO₄^3? more (p < 0.05) than the control. Eleven taxa belonging to 6 classes and 11 orders were recorded. Macrofauna was significantly more diversified (Mann–Whitney test: p < 0.05) in terms of Shannon index of diversity in the planted beds (0.25–0.44 bits/ind.) than in the control (0.08–0.23 bits/ind.). But macrofauna settlement presents a relative homogeneity between the beds (index Jaccard = 0.63). Its abundance was three times higher in the planted bed than in the control. From the surface to the bottom of the beds, macrofauna diversity and abundance decreased and were heavily dominated by Annelida. The significant relationships were only observed between Insecta and Myriapoda in the control.     

Sex and rank in competitive brood hierarchies influence stress levels in nestlings of a sexually dimorphic bird

Studies of sibling competition within brood hierarchies have rarely assessed simultaneously the effects of sex and rank in the brood hierarchy on traits other than offspring mortality and differential growth. We studied the expression of heat-shock proteins (Hsps) to assess the physiological stress response to different combinations of sex and position within competitive brood hierarchies in the black kite Milvus migrans (Bodd.), a sexually dimorphic raptor showing facultative siblicide. Senior males showed higher stress levels than did senior females and younger siblings of each sex as revealed by Hsp60 values. The analysis of Hsp70 levels indicated that nestlings from broods in which the senior chick was a male showed higher stress levels than did nestlings from broods in which the senior chick was a female. In addition, levels of Hsp60 were related negatively to nutritional condition expressed as levels of plasmatic albumin. This suggests that the sex of senior chicks may be key in determining their stress level and that of their siblings, which is probably associated with sibling competition by fighting within brood hierarchies. The comparatively higher stress levels of senior males (and their siblings) may be a consequence of their ability to exploit their potential advantage from being the head start while avoiding a possible competitive disadvantage from being the smaller sex, independent of environmental conditions determining the probability of brood reduction. Differential stress levels depending on sex and rank in the brood hierarchy may be a consequence of parental control of offspring behaviour through differential resource allocation (e.g. yolk androgens) or it may reflect adaptations of particular chicks (senior males) to enhance their competitive ability within brood hierarchies.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 383–390.     

Prevalence and Spatial Distribution of Entamoeba histolytica/dispar and Giardia lamblia among Schoolchildren in Agboville Area (C?te d'Ivoire)

Background

New efforts are being made to improve understanding of the epidemiology of the helminths and intensifying the control efforts against these parasites. In contrast, relatively few studies are being carried out in this direction for the intestinal protozoa. To contribute to a better comprehension of the epidemiology of the intestinal protozoa, prevalence, and spatial distribution of Entamoeba histolytica/dispar and Giardia lamblia, and their association with drinking water supplies, were determined in the Agboville department in southeast Côte d''Ivoire.

Methods/Findings

Stool samples were taken from more than 1,300 schoolchildren in the third year of primary education (CE1) from 30 primary schools and preserved in SAF (sodium acetate-acetic acid-formalin). The samples were analyzed by formalin-ether concentration. Then, a survey questionnaire addressed to schoolchildren and school directors was used to collect data on water supplies. Prevalence of E. histolytica/dispar and G. lamblia were, respectively, 18.8% and 13.9%. No particular focus zone was observed in the spatial distribution of the two species. Significant negative association was observed between use of tap water and high prevalence of E. histolytica/dispar infection (OR = 0.83, p = 0.01). High prevalence of G. lamblia infection was positively associated with use of ponds as the source of drinking water (OR = 1.28, p = 0.009).

Conclusion

These two species of pathogenic protozoa are present with substantial prevalence in this area of Côte d''Ivoire. Although their spatial distribution is not focused in any one place, determination of the population segments with the highest levels of infection will help to target the chemotherapeutic fight. To reinforce treatment with chemotherapeutic agents, tap water should be made available in all the localities of this area.     

Assessment of the effects of transgenic Bt cotton Bollgard II on the abundance of nontarget arthropods in Burkina Faso

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