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Community Ecology
Authors: M. Idbella, M. Zotti, G. Cesarano, T. Fechtali, S. Mazzoleni, and G. Bonanomi

Abstract

Plant litter decomposition is a crucial process of nutrient cycling within ecosystems. However, many studies have shown that, apart from its several beneficial effects, organic matter decomposition can be disadvantageous to seed germination, seedling growth, and physiological activity of plants. Litter decomposition was reported to affect both plants and their associated soil microbial communities. The aim of this work was to test the relationships between seed-associated endophytic fungi on the either positive or negative plant's response to different litter types. Leaf material of four species was collected and used in a decomposition experiment inside a growth chamber for 120 days. The plant growth experiment was set in a greenhouse using Trifolium repens and Triticum durum with and without their associated endophytic fungi in the presence of the different litter species at two decay levels (fresh litter and after 120 days of decomposition). Results demonstrated that fresh litter exerted a strong inhibition effect on the plant total biomass when compared to decomposed litter. Moreover, seed-associated endophytic fungi enhanced the inhibitory effect of litter in the observed experimental conditions. The removal of seed-associated endophytic fungi improved the capacity of tested plants to resist to litter inhibitory effect.

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Abstract

Artificial light at night can impact numerous diurnal species by influencing their distribution and habits. In this study, artificial lights placed on the Jacques Cartier bridge in Montreal, Canada were evaluated to determine their impact on insects, insectivorous birds and peregrine falcons. The impact was measured the year the illumination begun and the year following (two years in total). Insect distribution and abundance at three different sites around the bridge was measured. Insectivorous bird abundance and activity were evaluated by observing the cliff swallow as a proxy. Peregrine falcon presence and nesting behavior at the bridge was measured. Insects (aerial and aquatic) were found to be more abundant closer to the illuminated part of the bridge and particularly in the year following the illumination's beginning. Similarly, cliff swallows were more abundant at the bridge the year following the start of the illumination and their activity was more important closer to the illuminated section. Peregrine falcons were only present at the bridge in the year following the beginning of the illumination and specifically at the illuminated part of the bridge. No nesting was detected. These three groups are connected to each other through a food chain in which insect abundance impacts insectivorous bird abundance, which in turn impacts peregrine falcon presence. The illumination therefore positively impacts these three groups separately and together through their food chain. This research highlights the importance of monitoring bird and insect population close to the bridge and further continuation of these observations are necessary to determine if the observed tendency will continue to develop throughout the years.

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Abstract

Plant community diversity is a major research focus in community ecology. The relationship between diversity patterns and different diversity indices is important for developing and improving biodiversity protection. In order to fully understand multi-dimensional diversity patterns of the subalpine meadow on Heyeping peak of Luya Mountain, we used a systematic sampling method and set 150 1 m × 1 m plots in June of 2018. Based on an analysis of the subalpine meadow community on Heyeping peak, we measured multiple diversity indices, carried out a correlation analysis between diversity and environmental factors, and compared correlations among different diversity indices. The goal was to clarify the ecological mechanisms and variation among various diversity indices and environmental factors. The main results were as follows: (1) The species diversity distribution was uniform, the taxonomic level was narrow, functional differences were small, and different pedigree structures were present in each plot. (2) A stable correlation between pedigree diversity index (PD) and species diversity index indicated niche conservativism; the net relatedness index (NRI) of community lineage structure was significantly correlated with the nearest species taxon index (NTI), species richness, and evenness index, indicating that plant community composition in the study area is mainly affected by habitat filtration. (3) The average taxonomic distinctness index (Λ+) and the average taxonomic distinctness index (Λ+) had a stable correlation; only the functional richness index (FRic) and Patrick species richness index were closely related. (4) Among the selected environmental factors, only the forest line had a stable correlation with species diversity index and PD and showed a negative correlation change, indicating an “edge effect” distribution of species diversity in the study area. In summary, the forest line was the key factor affecting the distribution of species diversity in the study area and the species relationships within the community. This work was supported by the National Natural Science Foundation of China (31400358).

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Community Ecology
Authors: D. M. S. Abessa, B. R. F. Rachid, L. P. Zaroni, M. R. Gasparro, Y. A. Pinto, M. C. Bícego, M. A. Hortellan, J. E. S. Sarkis, P. Muniz, L. B. Moreira, and E. C. P. M. Sousa

Abstract

The Santos Estuarine System (SES) is a complex of bays, islands, estuarine channels, and rivers located on the Southeast coast of Brazil, in which multiple contaminant sources are situated in close proximity to mangroves and other protected areas. In this study, the composition and structure of the macrobenthic communities of SES were described and ninety-nine species were identified, with the predominance of polychaetes and bivalve mollusks. The benthic assemblages also showed strong signs of stress, as indicated by the low abundance, richness and diversity, and the dominance of opportunistic species. Integrated analysis including sediment characteristics related to natural and anthropogenic factors (e.g., sediment chemistry, and toxicity) indicated that benthic fauna from the inner portions of the SES and vicinities of the SSOS diffusers as Santos Bay were affected. Some locations at the mouths of Santos and Sao Vicente estuaries exhibited moderate disturbance. In other sites from the mouth of São Vicente and Bertioga channels, and Santos Bay, the benthic fauna were considered not degraded. Our results suggest that a combination of both environmental factors and contaminants were responsible for the benthic community structure.

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Abstract

Environmental changes have been rapidly increasing in the last decades, causing unprecedented shifts in biodiversity. The impacts of biodiversity changes on ecosystem processes depend on the traits of affected species and their functional redundancy at the community level. The generated data on biodiversity-functioning in marine environments are still fragmentary and predictions on how species, communities and ecosystems will respond to the ongoing global changes are still uncertain. This selection of manuscripts presents the efforts of researchers around the world towards a better understanding on the mechanisms driving biodiversity and functioning patterns in marine ecosystems. The issue is composed of studies about first records of diversity and single species patterns in overlooked marine communities, effects of pollution in shaping species composition, foundation species and the impact of their loss on local communities, and the relevance of ecological interactions and species’ traits in structuring marine food webs. We conclude that more field and experimental studies combined to modelling are needed for understanding mechanisms that currently determine the structure and functioning of ecosystems and for improving predictions under global change scenarios.

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Abstract

The Moroccan Atlantic coast is considered as one of the richest fishing areas in the world, having rich biodiversity, and supporting the fisheries sector. However, studies have shown that the ecosystem presently suffers from overexploitation of fishery resources and environmental degradation. To quantify these impacts, the characterization of the ecosystem is essential. In this work, an Ecopath model (EwE), which assumes steady-state and mass-balanced conditions for the Moroccan Atlantic coast ecosystem, was developed and balanced. Network analysis included in the Ecopath software package was used to estimate trophic interactions and the maturity of the ecosystem. The model consisted of 29 functional groups. The results showed a Total System Throughput (TST) which is comprised mainly of flows into detritus, followed by export, consumption, and respiration. Systemic indicators, suggest that the Moroccan Atlantic coast is an immature and developing ecosystem. Further observations on the functioning and dynamics of the ecosystem are discussed.

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European Journal of Microbiology and Immunology
Authors: Ralf Ignatius, Christiane Berg, Chris Weiland, Angela Darmer, Thilo Wenzel, Marion Lorenz, Jörg Fuhrmann, and Michael Müller

Stool antigen tests are recommended for the diagnosis of Helicobacter pylori infection. Here, we compared two novel assays, i.e., one enzyme immunoassay (EIA) and one immunochromatography assay (ICA), with a chemiluminescence immunoassay (CLIA) that had previously been compared with rapid urease test, histology, and urea breath test. Two hundred sixty-six frozen stool samples with defined CLIA results (42 positives, 219 negatives, and 5 samples with borderline results) collected between January and May 2018 were thawed and immediately tested by EIA, ICA, and CLIA.

In 248 samples with repeatedly positive/negative CLIA results, EIA and ICA were positive for 40 and 37 of 41 CLIA-positive samples and yielded negative results for 206 and 201 of 207 CLIA-negative samples, respectively. There was a high positive percent agreement (EIA, 97.6%; 95% confidence interval (95% CI), 86.3–100%; ICA, 90.2%; 95% CI, 76.9–96.7%), as well as a negative percent agreement between the assays (EIA, 99.5%; 95% CI, 97.0–100%; ICA, 97.1%; 95% CI, 93.7–98.8%). This was further supported by kappa values indicating very good agreement (CLIA vs. EIA, 0.971; CLIA vs. ICA, 0.857). In conclusion, both EIA and ICA comprise valuable assays for the detection of H. pylori antigen in stool samples.

Open access

Campylobacter jejuni and Campylobacter coli are among the leading causes of gastroenteritis in humans worldwide, particularly in Africa. Poultry remains a major source of Campylobacter species and a vector of transmission to humans.

This pilot study was aimed at isolating and determining the antibiotic susceptibility profiles of Campylobacter spp. from fresh poultry droppings collected from poultry farms in Lagos State, Nigeria. Susceptibility was assessed using the CLSI standards.

Standard microbiological methods were used in isolation, identification, and characterization of Campylobacter spp. Isolates were subjected to antibiotic susceptibility testing by the disk diffusion method.

Of the 150 poultry droppings analyzed, 8 (5.3%) harbored Campylobacter spp. All isolates proved to be C. coli since they were all negative for the hip gene. A percentage of 100% showed resistance to nalidixic acid, chloramphenicol, cloxacillin, and streptomycin. While 87.5% were susceptible to amoxicillin and amoxicillin/clavulanic acid, 62.5% were susceptible to tetracycline. Surprisingly, 62.5% of C. coli had decreased (intermediate) susceptibility to erythromycin.

Although there was a low prevalence of C. coli from poultry in this study, the presence of antibiotic resistant strains circulating the food chain could result in treatment failures and difficulty in case management if involved in infections of humans.

Open access
European Journal of Microbiology and Immunology
Authors: Abdelaziz Ed-Dra, Fouzia Rhazi Filali, Slimane Khayi, Said Oulghazi, Brahim Bouchrif, Abdellah El Allaoui, Bouchra Ouhmidou, and Mohieddine Moumni

Salmonella is a major cause of morbidity and mortality in humans worldwide, and the infection with multidrug-resistant strains can cause severe diseases. This study was designed to evaluate the antimicrobial resistance, to detect the virulence genes, and to study the genetic diversity of isolated Salmonella strains using 16S rRNA sequences. For this, 34 Salmonella strains isolated from sausages were identified using biochemical and serological methods. Molecular tools were used to evaluate the presence of virulence genes (orgA, sitC, sipB, spiA, iroN, and sifA) using simplex and multiplex polymerase chain reaction (PCR) and to sequence 16S rRNA genes for phylogenetic analysis. The susceptibility to 24 selected antibiotics was also studied. The results of this study showed that all isolated Salmonella were positive for targeted virulence genes and were resistant to at least one antibiotic. However, the multidrug resistance was observed in 44% of isolated strains. The phylogenetic analysis of 16S rRNA sequences highlighted that Salmonella isolates were divided into 3 clusters and 3 sub-clusters, with a ≥98% similarity to Salmonella enterica species. From this study, we conclude that sausages are considered as a potential source of Salmonella, which could be a major risk to public health.

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Sorghum bicolor (L.) Moench contains various phenolic compounds such as anthocyanin. Eleven sorghum accessions were classified into five groups by grain colour and their antioxidant activities were measured as well as the contents of total phenolic compounds (TPC) and anthocyanins in sorghum grains. The grain colour was related to TPC content, but not to monomelic anthocyanin content. Moreover, the overall patterns of antioxidant activity levels in 2,2-Diphenyl-1-picrylhydrazyl (DPPH) or 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay were similar to those of the TPC content. Correlations between TPC and anthocyanin contents were statistically significant and positive (P < 0.05). TPC content showed also a strong positive correlation to DPPH and ABTS antioxidant activities. The results provide the basic data for breeding of sorghum varieties containing large amounts of antioxidants.

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