Linking organic matter chemistry with soil aggregate stability: Insight from 13C NMR spectroscopy

Soil aggregation is considered as a crucial process in agro-system sustainability due to the role in soil physical, chemical and biological dynamics. Here we tested the hypothesis that the initial chemical traits of organic matter (OM) may help to explain the variability of soil aggregation dynamics after organic amendment. We characterized ten OM types (alfalfa litter, biochar, cellulose, glucose, green compost, maize litter, manure compost, meat powder, sawdust, and solid digestate) by 13C-CPMAS NMR and elemental chemical features to investigate the effects of amendment quality on soil aggregation. In a manipulative factorial experiment, dry samples (200 g) of three soil types (S1, S2 and S3) with different texture, high pH (7\u20139), and similar OM content, were incorporated with 4 g (2% w/w) of dry, 2 mm-grounded OM, incubated in mesocosms for 300 days under controlled temperature (18 \ub1 2 \ub0C night and 24 \ub1 2 \ub0C day), and sampled at 4 dates for measuring aggregation index (AI), based on water stability of soil aggregates (WSA). We found that meat powder and alfalfa litter induced a rapid initial increase of AI, exceeding that of the controls by one to two orders of magnitude, likely acting as a C source for microbes. Biochar incorporation in soil barely affected AI, with intermediate effects with other OM types. Considering C bond types corresponding to OM 13C-CPMAS NMR spectral regions, carbonyl C was only correlated to early AI, possibly due to overlapping signals of amide structures; O-alkyl C and di-O-alkyl C (carbohydrate fraction) were positively associated to AI, indicating a promoting effect on soil structure, while aromatic C fractions showed an opposite pattern, possibly related to aggregate protection by coatings associated to water repellency, or to direct aggregate internal binding. This study demonstrates that OM chemical quality plays an important role in soil aggregation process, with the molecular composition defined by 13C-CPMAS NMR spectroscopy being more predictive of aggregation dynamics compared to classical elemental features. As such, this study provides a significant novel contribution to clarify the relationships between OM chemistry and soil aggregation

Linking organic matter chemistry with soil aggregate stability: Insight from 13C NMR spectroscopy

Soil aggregation is considered as a crucial process in agro-system sustainability due to the role in soil physical, chemical and biological dynamics. Here we tested the hypothesis that the initial chemical traits of organic matter (OM) may help to explain the variability of soil aggregation dynamics after organic amendment. We characterized ten OM types (alfalfa litter, biochar, cellulose, glucose, green compost, maize litter, manure compost, meat powder, sawdust, and solid digestate) by 13C-CPMAS NMR and elemental chemical features to investigate the effects of amendment quality on soil aggregation. In a manipulative factorial experiment, dry samples (200 g) of three soil types (S1, S2 and S3) with different texture, high pH (7\u20139), and similar OM content, were incorporated with 4 g (2% w/w) of dry, 2 mm-grounded OM, incubated in mesocosms for 300 days under controlled temperature (18 \ub1 2 \ub0C night and 24 \ub1 2 \ub0C day), and sampled at 4 dates for measuring aggregation index (AI), based on water stability of soil aggregates (WSA). We found that meat powder and alfalfa litter induced a rapid initial increase of AI, exceeding that of the controls by one to two orders of magnitude, likely acting as a C source for microbes. Biochar incorporation in soil barely affected AI, with intermediate effects with other OM types. Considering C bond types corresponding to OM 13C-CPMAS NMR spectral regions, carbonyl C was only correlated to early AI, possibly due to overlapping signals of amide structures; O-alkyl C and di-O-alkyl C (carbohydrate fraction) were positively associated to AI, indicating a promoting effect on soil structure, while aromatic C fractions showed an opposite pattern, possibly related to aggregate protection by coatings associated to water repellency, or to direct aggregate internal binding. This study demonstrates that OM chemical quality plays an important role in soil aggregation process, with the molecular composition defined by 13C-CPMAS NMR spectroscopy being more predictive of aggregation dynamics compared to classical elemental features. As such, this study provides a significant novel contribution to clarify the relationships between OM chemistry and soil aggregation

Litter chemistry explains contrasting feeding preferences of bacteria, fungi, and higher plants

AbstractLitter decomposition provides a continuous flow of organic carbon and nutrients that affects plant development and the structure of decomposer communities. Aim of this study was to distinguish the feeding preferences of microbes and plants in relation to litter chemistry. We characterized 36 litter types by 13C-CPMAS NMR spectroscopy and tested these materials on 6 bacteria, 6 fungi, and 14 target plants. Undecomposed litter acted as a carbon source for most of the saprophytic microbes, although with a large variability across litter types, severely inhibiting root growth. An opposite response was found for aged litter that largely inhibited microbial growth, but had neutral or stimulatory effects on root proliferation. 13C-CPMAS NMR revealed that restricted resonance intervals within the alkyl C, methoxyl C, O-alkyl C and di-O-alkyl C spectral regions are crucial for understanding litter effects. Root growth, in contrast to microbes, was negatively affected by labile C sources but positively associated with signals related to plant tissue lignification. Our study showed that plant litter has specific and contrasting effects on bacteria, fungi and higher plants, highlighting that, in order to understand the effects of plant detritus on ecosystem structure and functionality, different microbial food web components should be simultaneously investigated.</jats:p

Linking bacterial and eukaryotic microbiota to litter chemistry: Combining next generation sequencing with 13 C CPMAS NMR spectroscopy

Microbial succession over decomposing litter is controlled by biotic interactions, dispersal limitation, grazing pressure, and substrate chemical changes. Recent evidence suggests that the changes in litter chemistry and microbiome during decomposition are interdependent. However, most previous studies separately addressed the microbial successional dynamics or the molecular changes of decomposing litter. Here, we combined litter chemical characterization by 13 C NMR spectroscopy with next generation sequencing to compare leaf litter chemistry and microbiome dynamics using 30 litter types, either fresh or decomposed for 30 and 180 days. We observed a decrease of cellulose and C/N ratio during decomposition, while lignin content and lignin/N ratio showed the opposite pattern. 13 C NMR revealed significant chemical changes as microbial decomposition was proceeding, with a decrease in O-alkyl C and an increase in alkyl C and methoxyl C relative abundances. Overall, bacterial and eukaryotic taxonomical richness increased with litter age. Among Bacteria, Proteobacteria dominated all undecomposed litters but this group was progressively replaced by members of Actinobacteria, Bacteroidetes, and Firmicutes. Nitrogen-fixing genera such as Beijerinckia and Rhizobium occurred both in undecomposed as well as in aged litters. Among Eukarya, fungi belonging to the Ascomycota phylum were dominant in undecomposed litter with the typical phyllospheric genus Aureobasidium. In aged litters, phyllospheric species were replaced by zygomycetes and other ascomycetous and basidiomycetous fungi. Our analysis of decomposing litter highlighted an unprecedented, widespread occurrence of protists belonging to the Amebozoa and Cercozoa. Correlation network analysis showed that microbial communities are non-randomly structured, showing strikingly distinct composition in relation to litter chemistry. Our data demonstrate that the importance of litter chemistry in shaping microbial community structure increased during the decomposition process, being of little importance for freshly fallen leaves

Mesenteric panniculitis presenting with acute non-occlusive colonic ischemia

<p>Abstract</p> <p>Background</p> <p>The role of positron emission tomography (PET) of the mesentery as a diagnostic modality in cases of mesenteric panniculitis is unclear.</p> <p>Case presentation</p> <p>A 67-year-old woman presented with rectal bleeding due to nonocclusive colonic ischemia. Abdominal CT showed features of mesenteric panniculitis. PET-CT demonstrated no abnormal fluorine-18 fluordeoxyglucose uptake in the affected mesentery or any surrounding lymph nodes. Laparoscopic biopsies from a thickened segment of mesenteric fat excluded neoplastic infiltration.</p> <p>Conclusions</p> <p>In cases of unexplained ischemic colitis, panniculitis should be considered a possible diagnosis. PET-CT may be negative for fluorine-18 fluordeoxyglucose uptake in this condition. As of known false-negative PET-CT results in mesenteric panniculitis, PET-CT has a limited role in the diagnostic work-up.</p

EpCAM expression in primary tumour tissues and metastases: an immunohistochemical analysis

Epithelial cell adhesion molecule (EpCAM) is a cell surface protein with oncogenic features that is expressed on healthy human epithelia and corresponding malignant tumours. EpCAM expression frequently correlates with more aggressive tumour behaviour and new EpCAM-specific therapeutic agents have recently been approved for clinical use in patients with cancer. However, no consensus exists on how and when to evaluate EpCAM expression in patients with cancer

Different pathways but same result? Comparing chemistry and biological effects of burned and decomposed litter

Litter burning and biological decomposition are oxidative processes co-occurring in many terrestrial ecosystems, producing organic matter with different chemical properties and differently affecting plant growth and soil microbial activity. Here, we tested the chemical convergence hypothesis (i.e. materials with different initial chemistry tend to converge towards a common profile, with similar biological effects, as the oxidative process advances) for burning and decomposition. We compared the molecular composition of 63 organic materials - 7 litter types either fresh, decomposed for 30, 90, 180 days, or heated at 100, 200, 300, 400, 500 \ub0C - as assessed by 13C NMR. We used litter water extracts (5% dw) as treatments in bioassays on plant (Lepidium sativum) and fungal (Aspergillus niger) growth, and a washed quartz sand amended with litter materials (0.5 % dw) to assess heterotrophic respiration by CO2 flux chamber. We observed different molecular variations for materials either burning (i.e. a sharp increase of aromatic C and a decrease of most other fractions above 200 \ub0C) or decomposing (i.e. early increase of alkyl, methoxyl and N-alkyl C and decrease of O-alkyl and di-O-alkyl C fractions). Soil respiration and fungal growth progressively decreased with litter age and temperature. Plant growth underwent an inhibitory effect by untreated litter, more and less rapidly released over decomposing and burning materials, respectively. Correlation analysis between NMR and bioassay data showed that opposite responses for soil respiration and fungi, compared to plants, are related to essentially the same C molecular types. Our findings suggest a functional convergence of decomposed and burnt organic substrates, emerging from the balance between the bioavailability of labile C sources and the presence of recalcitrant and pyrogenic compounds, oppositely affecting different trophic levels

Windstorm disturbance triggers multiple species invasion in an urban Mediterranean forest

Plant invasion in forest ecosystems is a serious ecological and economic issue, deserving attention by researchers, managers and policy-makers worldwide. Many invasive plants have been reported as early successional species able to colonize disturbed areas following abrupt changes in microhabitat and resource availability. We investigated disturbance effects of a severe windstorm generated by a wet microburst (hail and rain at 160 mm h-1) remarkably affecting the canopy cover of an old-growth Quercus ilex urban forest in Southern Italy. This stand-replacing disturbance produced a mosaic of 103 gaps, 5.6 to 1632 m2 in size, over an area of 1.53 ha, uprooting 76% of the trees and decreasing thereby 85% of the standing above-ground dry biomass into the gaps. By intensive monitoring we compared above- and below-ground microclimate, soil moisture and mineral N availability in paired disturbed and control areas of the study forest. Within newly formed gaps we observed a seasonally consistent 70% higher content of nitrate nitrogen, 29% and 47% decreases of ammonia nitrogen in summer and autumn, respectively, and a higher moisture in topsoil, in addition to different above- and below-ground microclimatic conditions, with canopy cover mitigating extreme temperatures. One year after the windstorm, the microhabitat shift promoted the establishment in gaps of 15 native and 10 alien taxa previously absent in both disturbed and control plots. In such conditions, the rarefaction of the dominant Q. ilex canopy cover and the occurrence of empty niches prone to invasion could dramatically affect the local community structure and diversity. Our data indicate that stand-replacing windstorm can transiently transform the studied urban evergreen forest to an early allogenic successional community dominated, in the medium and large gaps, by annual and perennial non-native species. This is particularly relevant under a perspective of possible increasing frequency of windstorm events in the Mediterranean region in the near future

Characteristics of people living in Italy after a cancer diagnosis in 2010 and projections to 2020

BACKGROUND: Estimates of cancer prevalence are widely based on limited duration, often including patients living after a cancer diagnosis made in the previous 5 years and less frequently on complete prevalence (i.e., including all patients regardless of the time elapsed since diagnosis). This study aims to provide estimates of complete cancer prevalence in Italy by sex, age, and time since diagnosis for all cancers combined, and for selected cancer types. Projections were made up to 2020, overall and by time since diagnosis. METHODS: Data were from 27 Italian population-based cancer registries, covering 32% of the Italian population, able to provide at least 7 years of registration as of December 2009 and follow-up of vital status as of December 2013. The data were used to compute the limited-duration prevalence, in order to estimate the complete prevalence by means of the COMPREV software. RESULTS: In 2010, 2,637,975 persons were estimated to live in Italy after a cancer diagnosis, 1.2 million men and 1.4 million women, or 4.6% of the Italian population. A quarter of male prevalent cases had prostate cancer (n\u2009=\u2009305,044), while 42% of prevalent women had breast cancer (n\u2009=\u2009604,841). More than 1.5 million people (2.7% of Italians) were alive since 5 or more years after diagnosis and 20% since 6515 years. It is projected that, in 2020 in Italy, there will be 3.6 million prevalent cancer cases (+\u200937% vs 2010). The largest 10-year increases are foreseen for prostate (+\u200985%) and for thyroid cancers (+\u200979%), and for long-term survivors diagnosed since 20 or more years (+\u200945%). Among the population aged 6575 years, 22% will have had a previous cancer diagnosis. CONCLUSIONS: The number of persons living after a cancer diagnosis is estimated to rise of approximately 3% per year in Italy. The availability of detailed estimates and projections of the complete prevalence are intended to help the implementation of guidelines aimed to enhance the long-term follow-up of cancer survivors and to contribute their rehabilitation need

Diaphragmatic Electromyography Analysis During Two Different Mechanical Ventilation Techniques in Patients with Neuromuscular Diseases

Abstract-The aim of the present study is to analyse changes in the diaphragmatic electromyography integral, as a direct expression of the patients inspiratory effort and index of neural respiratory drive, and parameters associated with ventilatory function in patients with prolonged weaning under Pressure Support Ventilation (PSV) and Neurally Adjusted Ventilatoy Assist (NAVA). Five patients affected by neuromuscular diseases were recruited. Each patient underwent a sequence of decreasing inspiratory support levels under NAVA and PSV, randomly assigned, from a baseline to a final level. At baseline, the value of diaphragmatic electromyography integral was higher under NAVA compared to PSV and increased in both ventilation modes progressing to final level. Higher values of inspiratory time and neural inspiratory time were observed in PSV at final level compared to baseline level. Conversely, a significant decrease of neural inspiratory time from baseline level to final level was observed in NAVA. Tidal volume at final level was significantly lower than at baseline level in both ventilation modes. These preliminary results show that in prolonged weaning patients affected by neuromuscular disease NAVA ventilation is associated to a higher diaphragmatic electromyography activity compared to PSV with same level of ventilation and subjective comfort