scholarly journals Resource stoichiometry shapes community invasion resistance via productivity-mediated species identity effects

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182035 ◽  
Author(s):  
Tianjie Yang ◽  
Gang Han ◽  
Qingjun Yang ◽  
Ville-Petri Friman ◽  
Shaohua Gu ◽  
...  
Keyword(s):  
Resource Availability ◽  
Relative Concentration ◽  
Microbial Community Composition ◽  
Community Diversity ◽  
Invasion Resistance ◽  
Resident Species ◽  
Negative Effects ◽  
Species Identity ◽  
Community Resistance ◽  
The Mean

Diversity–invasion resistance relationships are often variable and sensitive to environmental conditions such as resource availability. Resource stoichiometry, the relative concentration of different elements in the environment, has been shown to have strong effects on the physiology and interactions between different species. Yet, its role for diversity–invasion resistance relationships is still poorly understood. Here, we explored how the ratio of nitrogen (N) and phosphorus affects the productivity and invasion resistance of constructed microbial communities by a plant pathogenic bacterium, Ralstonia solanacearum . We found that resource stoichiometry and species identity effects affected the invasion resistance of communities. Both high N concentration and resident community diversity constrained invasions, and two resident species, in particular, had strong negative effects on the relative density of the invader and the resident community productivity. While resource stoichiometry did not affect the mean productivity of the resident community, it favoured the growth of two species that strongly constrained invasions turning the slope of productivity–invasion resistance relationship more negative. Together our findings suggest that alterations in resource stoichiometry can change the community resistance to invasions by having disproportionate effects on species growth, potentially explaining changes in microbial community composition under eutrophication.

scholarly journals Efficacy of SSRIs on cognition of Alzheimer's disease patients treated with cholinesterase inhibitors

2009 ◽  
Vol 22 (1) ◽  
pp. 114-119 ◽  
Author(s):  
Luca Rozzini ◽  
Barbara Vicini Chilovi ◽  
Marta Conti ◽  
Erik Bertoletti ◽  
Marina Zanetti ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cholinesterase Inhibitors ◽  
Mmse Score ◽  
Joint Effect ◽  
Negative Effects ◽  
Multidimensional Assessment ◽  
Degree Of Protection ◽  
Depressed Patients ◽  
The Mean

ABSTRACTBackground: This study examines the joint effect on cognition of selective serotonin re-uptake inhibitors (SSRIs) and cholinesterase inhibitors (AChEIs) in depressed patients affected by Alzheimer's disease (AD) living at home.Methods: The study was conducted in two different outpatient neurological clinics. 338 patients with probable AD were treated with ChEis (donepezil, rivastigmine and galantamine) as per the clinician's judgment and were observed for nine months. At study entry, participants underwent a multidimensional assessment evaluating cognitive, functional and psychobehavioral domains. All patients were evaluated at baseline, after one (T1), three (T2) and nine months (T3). Patients were grouped in three different categories (patients not depressed and not treated with SSRIs, patients depressed and treated with SSRIs, and patients depressed but not treated with SSRIs).Results: At baseline 182 were diagnosed as not depressed and not treated with SSRIs, 66 as depressed and treated with SSRIs, and 90 as depressed but not treated with SSRIs. The mean change in MMSE score from baseline to nine months showed that depressed patients not treated worsened in comparison with those not depressed and not treated with SSRIs (mean change −0.8 ± 2.3 vs 0.04 ± 2.9; p = 0.02) and patients depressed and treated with SSRI (mean change −0.8 ± 2.3 vs 0.1 ± 2.5; p = 0.03).Conclusions: In AD patients treated with AChEIs, SSRIs may exert some degree of protection against the negative effects of depression on cognition.

scholarly journals Rhizobacterial communities of five co-occurring desert halophytes

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5508 ◽  
Author(s):  
Yan Li ◽  
Yan Kong ◽  
Dexiong Teng ◽  
Xueni Zhang ◽  
Xuemin He ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
Plant Species ◽  
Bacterial Communities ◽  
Bacterial Community Composition ◽  
Community Diversity ◽  
Species Identity ◽  
Halostachys Caspica ◽  
Lycium Ruthenicum ◽  
Limonium Gmelinii

BackgroundRecently, researches have begun to investigate the microbial communities associated with halophytes. Both rhizobacterial community composition and the environmental drivers of community assembly have been addressed. However, few studies have explored the structure of rhizobacterial communities associated with halophytic plants that are co-occurring in arid, salinized areas.MethodsFive halophytes were selected for study: these co-occurred in saline soils in the Ebinur Lake Nature Reserve, located at the western margin of the Gurbantunggut Desert of Northwestern China. Halophyte-associated bacterial communities were sampled, and the bacterial 16S rDNA V3–V4 region amplified and sequenced using the Illumina Miseq platform. The bacterial community diversity and structure were compared between the rhizosphere and bulk soils, as well as among the rhizosphere samples. The effects of plant species identity and soil properties on the bacterial communities were also analyzed.ResultsSignificant differences were observed between the rhizosphere and bulk soil bacterial communities. Diversity was higher in the rhizosphere than in the bulk soils. Abundant taxonomic groups (from phylum to genus) in the rhizosphere were much more diverse than in bulk soils. Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Planctomycetes were the most abundant phyla in the rhizosphere, while Proteobacteria and Firmicutes were common in bulk soils. Overall, the bacterial community composition were not significantly differentiated between the bulk soils of the five plants, but community diversity and structure differed significantly in the rhizosphere. The diversity ofHalostachys caspica,Halocnemum strobilaceumandKalidium foliatumassociated bacterial communities was lower than that ofLimonium gmeliniiandLycium ruthenicumcommunities. Furthermore, the composition of the bacterial communities ofHalostachys caspicaandHalocnemum strobilaceumwas very different from those ofLimonium gmeliniiandLycium ruthenicum. The diversity and community structure were influenced by soil EC, pH and nutrient content (TOC, SOM, TON and AP); of these, the effects of EC on bacterial community composition were less important than those of soil nutrients.DiscussionHalophytic plant species played an important role in shaping associated rhizosphere bacterial communities. When salinity levels were constant, soil nutrients emerged as key factors structuring bacterial communities, while EC played only a minor role. Pairwise differences among the rhizobacterial communities associated with different plant species were not significant, despite some evidence of differentiation. Further studies involving more halophyte species, and individuals per species, are necessary to elucidate plant species identity effects on the rhizosphere for co-occurring halophytes.

scholarly journals Supplementation with High Doses of Vitamin D to Subjects without Vitamin D Deficiency May Have Negative Effects: Pooled Data from Four Intervention Trials in Tromsø

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Rolf Jorde ◽  
Moira Strand Hutchinson ◽  
Marie Kjærgaard ◽  
Monica Sneve ◽  
Guri Grimnes
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Serum Lipids ◽  
Randomized Clinical Trials ◽  
High Sensitivity ◽  
Vitamin D Supplementation ◽  
High Dose ◽  
Negative Effects ◽  
The Mean ◽  
Hs Crp

Data were pooled from four randomized clinical trials with vitamin D performed in Tromsø with weight reduction, insulin sensitivity, bone density, and depression scores as endpoints. Serum lipids, glycated hemoglobin (HbA1c), and high sensitivity C-Reactive Protein, (HS-CRP) were measured at baseline and after 6–12 months of supplementation with vitamin D 20 000 IU–40 000 IU per week versus placebo. A total of 928 subjects who completed the interventions were included. At baseline the mean serum 25-hydroxyvitamin D (25(OH)D) level in those given vitamin D was 55.9 (20.9) nmol/L and the mean increase was 82.4 (40.1) nmol/L. Compared with the placebo group there was in the vitamin D group at the end of the studies a slight, but significant, increase in HbA1c of 0.04%, an increase in HS-CRP of 0.07 mg/L in those with serum 25(OH)D < 50 nmol/L, and in those with low baseline HDL-C and serum 25(OH)D < 50 nmol/L a slight decrease serum HDL-C of 0.08 mmol/L (P<0.05). No serious side-effects were seen. In conclusion, in subjects without vitamin D deficiency, there is no improvement in serum lipids, HbA1c, or HS-CRP with high dose vitamin D supplementation. If anything, the effect is negative.

scholarly journals Spatial and Annual Variation in Microbial Abundance, Community Composition, and Diversity Associated With Alpine Surface Snow

2021 ◽  
Vol 12 ◽  
Author(s):  
Lucas Fillinger ◽  
Kerstin Hürkamp ◽  
Christine Stumpp ◽  
Nina Weber ◽  
Dominik Forster ◽  
...  
Keyword(s):  
Climate Change ◽  
Microbial Community ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Alpha Diversity ◽  
Community Diversity ◽  
Taxon Richness ◽  
European Alps ◽  
Prokaryotic Cell ◽  
Surface Snow

Understanding microbial community dynamics in the alpine cryosphere is an important step toward assessing climate change impacts on these fragile ecosystems and meltwater-fed environments downstream. In this study, we analyzed microbial community composition, variation in community alpha and beta diversity, and the number of prokaryotic cells and virus-like particles (VLP) in seasonal snowpack from two consecutive years at three high altitude mountain summits along a longitudinal transect across the European Alps. Numbers of prokaryotic cells and VLP both ranged around 104 and 105 per mL of snow meltwater on average, with variation generally within one order of magnitude between sites and years. VLP-to-prokaryotic cell ratios spanned two orders of magnitude, with median values close to 1, and little variation between sites and years in the majority of cases. Estimates of microbial community alpha diversity inferred from Hill numbers revealed low contributions of common and abundant microbial taxa to the total taxon richness, and thus low community evenness. Similar to prokaryotic cell and VLP numbers, differences in alpha diversity between years and sites were generally relatively modest. In contrast, community composition displayed strong variation between sites and especially between years. Analyses of taxonomic and phylogenetic community composition showed that differences between sites within years were mainly characterized by changes in abundances of microbial taxa from similar phylogenetic clades, whereas shifts between years were due to significant phylogenetic turnover. Our findings on the spatiotemporal dynamics and magnitude of variation of microbial abundances, community diversity, and composition in surface snow may help define baseline levels to assess future impacts of climate change on the alpine cryosphere.

scholarly journals Parasite species identity and local community diversity mediate effects of habitat fragmentation on bacterial microbiomes.

2020 ◽  
Author(s):  
Kelly A Speer ◽  
Tiago Teixeira ◽  
Alexis Brown ◽  
Susan Perkins ◽  
Katharina Dittmar ◽  
...  
Keyword(s):  
Habitat Fragmentation ◽  
Local Community ◽  
Parasite Species ◽  
Community Diversity ◽  
Species Identity

scholarly journals First data on habitat preference, diet and length-weight relationship of Gobius incognitus Kovačić & Šanda, 2016 (Pisces: Gobiidae)

2020 ◽  
Vol 61 (1) ◽  
pp. 67-78
Author(s):  
Francesco Tiralongo ◽  
Giuseppina Messina ◽  
Bianca Maria Lombardo
Keyword(s):  
Habitat Preference ◽  
Diet Analysis ◽  
Ionian Sea ◽  
Central Mediterranean ◽  
Species Identity ◽  
Weight Relationship ◽  
Important Prey ◽  
Ecological Aspects ◽  
The Mean ◽  
Relationship Of

In this work, we present first data on biological and ecological aspects of Gobius incognitus from specimens from the Ionian Sea (central Mediterranean Sea). In particular, we provided first data on habitat preference, diet and length-weight relationship of G. incognitus on material with confirmed species identity. The species preferred “mixed bottom” (sand and rocks), where it reached relatively high abundances. The diet analysis showed that G. incognitus is a generalist and opportunistic feeder. However, small benthic crustaceans were the most important prey group. The mean total length of specimens was 6.72 ± 1.85 cm and the growth was positive allometric.

scholarly journals Do high‐impact invaders have the strongest negative effects on abundant and functionally similar resident species?

2016 ◽  
Vol 30 (8) ◽  
pp. 1447-1453 ◽  
Author(s):  
Erica J. Case ◽  
Susan Harrison ◽  
Howard V. Cornell
Keyword(s):  
High Impact ◽  
Resident Species ◽  
Negative Effects

Ecotourism Destination Assessment using Tourist Potential Index in Zhemgang Dzongkhag, Bhutan

2020 ◽  
Vol 7 (2) ◽  
pp. 1-11
Author(s):  
Jigme Dorji ◽  
Dhan Gurung ◽  
Om Katel
Keyword(s):  
Resource Availability ◽  
Forest Cover ◽  
Scenic Beauty ◽  
The Past ◽  
Potential Index ◽  
Local Standard ◽  
Practical Guidelines ◽  
Tourism Resources ◽  
The Mean ◽  
International Visitors

Zhemgang is increasingly becoming a preferred destination for nature-based tourism with the increasing number of international visitors from 165 to 346 between 2013 and 2019. The attractions that contribute to the increasing number of visitors are 225,361.47 ha (94.17%) of area under forest cover, rich biodiversity, unexplored scenic beauty and unique Kheng culture. In the past years, five local standard hotels, five ecolodges and two homestays have added bed nights of international visitors from 420 in 2013 to 931 in 2018. This study was conducted to assessed 10 potential ecotourism destinations in Zhemgang on the basis of resource availability and preferential appeal by promoters for tourism resources using Tourist Potential Index (TPI). The TPI was found ranging between 17 and 31.75.The mean rank of the destinations varies between 1.47 and 9.47 and there is significance difference in resources appealed by the tour operators on resources availability in the destinations considered for this study; (χ2(2) = 229.07, p = 0.00). The TPI may be useful indicator in developing practical guidelines for tourism resources development in the region.

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