Comparing the impact of microplastics derived from a biodegradable and a conventional plastic mulch on plant performance

Agricultural lands have been identified as plastic sinks. One source is plastic mulches, which are a source of micro- and nano-sized plastics in agricultural soils. Because of their persistence, there is now a push towards developing biodegradable plastics, which are designed to undergo (partial) breakdown after entering the environment. Yet, limited research has investigated the impacts of both conventional and biodegradable plastics on distinct plants. Moreover, comparisons among studies are difficult due to differences in experimental design. This study directly compares the effects of artificially weathered conventional polyethylene (PE) and starch-based biodegradable polybutylene adipate terephthalate (PBAT) on four food crops, including two monocots (barley, Hordeum vulgare, and wheat, Triticum aestivum L.) and two dicots (carrot, Daucus carota, and lettuce, Lactuca sativa L.). We investigated the effects of environmentally relevant low, medium, and high (0.01 %, 0.1 %, 1 % w/w) concentrations of PE and starch-PBAT blend on seed germination (acute toxicity), and subsequently on plant growth and chlorophyll through a pot-plant experiment (chronic toxicity). Germination of all species was not affected by both plastics. However, root length was reduced for lettuce and wheat seedlings. No other effects were recorded on monocots. We observed a reduction in shoot length and bud wet weight of carrot seedlings for the highest concentration of PE and starch-PBAT blend. Chronic exposure resulted in a significant decrease in shoot biomass of barley and lettuce. Additionally, a positive increase in the number of leaves of lettuce was observed for both plastics. Chlorophyll content was increased in lettuce when exposed to PE and starch-PBAT blend. Overall, adverse effects in dicots were more abundant than in monocots. Importantly, we found that the biodegradable plastic caused more commonly adverse effects on plants compared to conventional plastic, which was confirmed by a mini-review of studies directly comparing the impact of conventional and biodegradable microplastics.

Tannins and Climate Change: Are Tannins Able To Stabilize Carbon in the Soil?

The interaction between tannins and proteins has been studied intensively for more than half a century as a result of its significance for various applications. In chemical ecology, tannins are involved in response to environmental stress, including biotic (pathogens and herbivores) and abiotic (e.g., drought) stress, and in carbon (C) and nutrient cycling. This perspective summarizes the newest insights into the role of tannins in soil processes, including the interaction with fungi leading to C stabilization. Recent knowledge presented here may help to optimize land management to increase or preserve soil C to mitigate climate change.

Radiation and temperature drive diurnal variation of aerobic methane emissions from Scots pine canopy

Methane emissions from plant foliage may play an important role in the global methane cycle, but their size and the underlying source processes remain poorly understood. Here, we quantify methane fluxes from the shoots of Scots pine trees, a dominant tree species in boreal forests, to identify source processes and environmental drivers, and we evaluate whether these fluxes can be constrained at the ecosystem-level by eddy covariance flux measurements. We show that shoot-level measurements conducted in forest, garden, or greenhouse settings; on mature trees and saplings; manually and with an automated CO2-, temperature-, and water-controlled chamber system; and with multiple methane analyzers all resulted in comparable daytime fluxes (0.144 ± 0.019 to 0.375 ± 0.074 nmol CH4 g-1 foliar d.w. h-1). We further find that these emissions exhibit a pronounced diurnal cycle that closely follows photosynthetically active radiation and is further modulated by temperature. These diurnal patterns indicate that methane production is associated with diurnal cycle of sunlight, indicating that this production is either a byproduct of photosynthesis-associated biochemical reactions (e.g., the methionine cycle) or produced through nonenzymatic photochemical reactions in plant biomass. Moreover, we identified a light-dependent component in stand-level methane fluxes, which showed order-of-magnitude agreement with shoot-level measurements (0.968 ± 0.031 nmol CH4 g-1 h-1) and which provides an upper limit for shoot methane emissions.

Polystyrene nanoparticles induce concerted response of plant defense mechanisms in plant cells

Recent advances in knowledge suggest that micro- and nanoplastics pose a threat to plant health, however, the responses of plants to this stressor are not well-known. Here we examined the response of plant cell defence mechanisms to nanoparticles of commonly used plastic, polystyrene. We used plant cell cultures of widely cultivated plants, the monocots wheat and barley (Triticum aestivum L., Hordeum vulgare L.) and the dicots carrot and tomato (Daucus carota L., Solanum lycopersicum L.). We measured the activities of enzymes involved in the scavenging of reactive oxygen species and nonenzymatic antioxidants and we estimated potential damages in plant cell structures and functioning via lipid peroxidation and DNA methylation levels. Our results demonstrate that the mode of action of polystyrene nanoparticles on plant cells involves oxidative stress. However, the changes in plant defence mechanisms are dependent on plant species, exposure time and nanoplastic concentrations. In general, both monocots showed similar responses to nanoplastics, but the carrot followed more the response of monocots than a second dicot, a tomato. Higher H2O2, lipid peroxidation and lower enzyme activities scavenging H2O2 suggest that tomato cells may be more susceptible to polystyrene-induced stress. In conclusion, polystyrene nanoplastics induce oxidative stress and the response of the plant defense mechanisms involving several chain reactions leading to oxidoreductive homeostasis.

Diterpenes and triterpenes show potential as biocides against pathogenic fungi and oomycetes: a screening study

OBJECTIVES

The aim was to screen di- and triterpenes as potential biocides against fungal pathogens (Alternaria sp., Fusarium avenaceum, F. sambucinum, Botrytis cinerea, Botryotina fuckeliana, Mycocentrospora acerina, Cylindrocarpon sp.) and oomycetes (Phytophthora cactorum, P. fragariae). Results We measured the antifungal activity of terpenes by estimating the growth area, ergosterol content and level of lipid peroxidation. Fungi and oomycetes were grown on solid media in Petri dishes. As a positive control, we used a common synthetic fungicide, fosetyl-Al. Di- and triterpenes showed promising potential as biocides against most of the studied species. The responses of fungi and oomycetes were dependent on the specific type of terpenes and identity of the fungi. Compared to synthetic fungicide, terpenes were equally effective as antifungal agents and even more effective for some species, especially for oomycetes. The terpene mode of action includes inhibition of ergosterol synthesis and increased lipid peroxidation. Conclusions Di- and triterpenes, natural compounds that are very abundant in northern countries, are excellent candidates for biocides.

Species-dependent responses of crop plants to polystyrene microplastics

Only recently there has been a strong focus on the impacts of microplastics on terrestrial crop plants. This study aims to examine and compare the effects of microplastics on two monocotyledonous (barley, Hordeum vulgare and wheat, Triticum aestivum), and two dicotyledonous (carrot, Daucus carota and lettuce, Lactuca sativa) plant species through two complimentary experiments. First, we investigated the effects of low, medium, and high (103, 105, 107 particles per mL) concentrations of 500 nm polystyrene microplastics (PS-MPs) on seed germination and early development. We found species-dependent effects on the early development, with microplastics only significantly affecting lettuce and carrot. When acutely exposed during germination, PS-MPs significantly delayed the germination of lettuce by 24%, as well as promoted the shoot growth of carrot by 71% and decreased its biomass by 26%. No effect was recorded on monocot species. Secondly, we performed a chronic (21 d) hydroponic experiment on lettuce and wheat. We observed that PS-MPs significantly reduced the shoot growth of lettuce by up to 35% and increased its biomass by up to 64%, while no record was reported on wheat. In addition, stress level indicators and defence mechanisms were significantly up-regulated in both lettuce and wheat seedlings. Overall, this study shows that PS-MPs affect plant development: impacts were recorded on both germination and growth for dicots, and responses identified by biochemical markers of stress were increased in both lettuce and wheat. This highlights species-dependent effects as the four crops were grown under identical conditions to allow direct comparison. For future research, our study emphasizes the need to focus on crop specific effects, while also working towards knowledge of plastic-induced impacts at environmentally relevant conditions.

Fast and reliable method to estimate global DNA methylation in plants and fungi with high-pressure liquid chromatography (HPLC)-ultraviolet detection and even more sensitive one with HPLC-mass spectrometry

DNA (Deoxyribonucleic acid) methylation is one of the epigenetic modifications of DNA, acting as a bridge between genotype and phenotype. Thus, disruption of DNA methylation pattern has tremendous consequences for organism development. Current methods to determine DNA methylation suffer from methodological drawbacks like high requirement of DNA and poor reproducibility of chromatograms. Here we provide a fast and reliable method using high-pressure liquid chromatography (HPLC)-ultraviolet (UV) detector and even more sensitive one with HPLC- mass spectrometry (MS) and we test this method with various plant and fungal DNA isolates. We optimized the preparation of the DNA degradation step to decrease background noise, we improved separation conditions to provide reliable and reproducible chromatograms and conditions to measure nucleotides in HPLC-MS. We showed that global DNA methylation level can be accurately and reproducibly measured with as little as 0.2 µM for HPLC-UV and 0.02 µM for HPLC-MS of methylated cytosine.

Drivers of intra-seasonal δ13 C signal in tree-rings of Pinus sylvestris as indicated by compound-specific and laser ablation isotope analysis

Carbon isotope composition of tree-ring (δ¹³ C_Ring ) is a commonly used proxy for environmental change and ecophysiology. δ¹³ C_Ring reconstructions are based on a solid knowledge of isotope fractionations during formation of primary photosynthates (δ¹³ C_P ), such as sucrose. However, δ¹³ C_Ring is not merely a record of δ¹³ C_P . Isotope fractionation processes, which are not yet fully understood, modify δ¹³ C_P during sucrose transport. We traced, how the environmental intra-seasonal δ¹³ C_P signal changes from leaves to phloem, tree-ring and roots, for 7 year old Pinus sylvestris, using δ¹³ C analysis of individual carbohydrates, δ¹³ C_Ring laser ablation, leaf gas exchange and enzyme activity measurements. The intra-seasonal δ¹³ C_P dynamics was clearly reflected by δ¹³ C_Ring , suggesting negligible impact of reserve use on δ¹³ C_Ring . However, δ¹³ C_P became increasingly ¹³ C-enriched during down-stem transport, probably due to post-photosynthetic fractionations such as sink organ catabolism. In contrast, δ¹³ C of water-soluble carbohydrates, analysed for the same extracts, did not reflect the same isotope dynamics and fractionations as δ¹³ C_P , but recorded intra-seasonal δ¹³ C_P variability. The impact of environmental signals on δ¹³ C_Ring , and the 0.5 and 1.7‰ depletion in photosynthates compared ring organic matter and tree-ring cellulose, respectively, are useful pieces of information for studies exploiting δ¹³ C_Ring .

WebTetrado: a webserver to explore quadruplexes in nucleic acid 3D structures

Quadruplexes are four-stranded DNA/RNA motifs of high functional significance that fold into complex shapes. They are widely recognized as important regulators of genomic processes and are among the most frequently investigated potential drug targets. Despite interest in quadruplexes, few studies focus on automatic tools that help to understand the many unique features of their 3D folds. In this paper, we introduce WebTetrado, a web server for analyzing 3D structures of quadruplex structures. It has a user-friendly interface and offers many advanced features, including automatic identification, annotation, classification, and visualization of the motif. The program applies to the experimental or in silico generated 3D models provided in the PDB and PDBx/mmCIF files. It supports canonical G-quadruplexes as well as non-G-based quartets. It can process unimolecular, bimolecular, and tetramolecular quadruplexes. WebTetrado is implemented as a publicly available web server with an intuitive interface and can be freely accessed at https://webtetrado.cs.put.poznan.pl/.

RNAsolo: a repository of cleaned PDB-derived RNA 3D structures

MOTIVATION

The development of algorithms dedicated to RNA 3D structures contributes to the demand for training, testing, and benchmarking data. A reliable source of such data derived from computational prediction is the RNA-Puzzles repository. In contrast, the largest resource with experimentally determined structures is the Protein Data Bank. However, files in this archive often contain other molecular data in addition to the RNA structure itself, which-to be used by RNA processing algorithms-should be removed.

RESULTS

RNAsolo is a self-updating database dedicated to RNA bioinformatics. It systematically collects experimentally determined RNA 3D structures stored in the PDB, cleans them from non-RNA chains, and groups them into equivalence classes. It allows users to download various subsets of data-clustered by resolution, source, data format, etc. - for further processing and analysis with a single click.

AVAILABILITY

The repository is publicly available at https://rnasolo.cs.put.poznan.pl.

The Utilisation of Solid Fuels Derived from Waste Pistachio Shells in Direct Carbon Solid Oxide Fuel Cells

The comprehensive results regarding the physicochemical properties of carbonaceous materials that are obtained from pistachio shells support their usage as solid fuels to supply direct carbon solid oxide fuel cells (DC-SOFCs). The influence of preparation conditions on variations in the chemical composition, morphology of the biochar powders, and degree of graphitization of carbonaceous materials were investigated. Based on structural investigations (X-ray diffraction analysis and Raman spectroscopy), it was observed that disordered carbon particles developed during the application of thermal treatments. The use of X-ray fluorescence enabled a comparative analysis of the chemical composition of the inorganic matter in biocarbon-based samples. Additionally, the gasification of carbonaceous-based samples vs. time at a temperature of 850 °C was investigated in a H2O or CO2 gas atmosphere. The analysis demonstrated the conversion rate of biochar obtained from pistachio shells to H2, CH4 and CO during steam gasification. The electrochemical investigations of the DC-SOFCs that were supplied with biochars obtained from pistachio shells were characterized by satisfactory values for the current and power densities at a temperature range of 700-850 °C. However, a higher power output of the DC-SOFCs was observed when CO2 was introduced to the anode chamber. Therefore, the impact of the Boudouard reaction on the performance of DC-SOFCs was confirmed. The chars that were prepared from pistachio shells were adequate for solid fuels for utilization in DC-SOFCs.

P–340 Novel non-invasive diagnostic options for endometriosis - based on glycome analysis

Study question

Could glycosylation changes on serum and/or urine glycoproteins be suitable biomarkers for the non-invasive diagnosis of endometriosis?

Summary answer

The glycosylation pattern on serum and urine glycoproteins differed significantly in endometriosis patients compared to controls, suggesting a novel role as biomarkers of the disease.

What is known already

There is little published on endometriosis and glycosylation, and most of the studies are conducted with tissue or peritoneal fluid samples, collected by invasive means. An Iraqi study draws attention to the importance of serum sialylation, which is dramatically changed in endometriosis patients after zoladex therapy, indicating that changes in serum sialylation may be a new biomarker of the disease. While glycosylation of urine in endometriosis has not been studied so far, in a study of endometrial cancer, the urinary level of two glycoproteins was significantly increased in the patients compared to the control group.

Study design, size, duration

This was a prospective study. In this basic research project, serum and urine samples were collected for glycome analysis in women with and without endometriosis, as diagnosed at laparoscopy. Glycated haemoglobin (HbA1c), fasting glucose levels as well as hormone levels were also collected from the patients to link our glycomic findings with metabolic and hormone profiles. The study was approved by the Research and Ethics Committee of the National Maternity Hospital, Dublin (EC19.2018).

Participants/materials, setting, methods

Samples from 24 cases of endometriosis (patients without previous anti-inflammatory or hormonal therapy, endometriosis was confirmed by laparoscopy) and 27 control patients (patients without endometriosis) were processed to analyse N-glycans (total serum), urine glycoproteins, and IgG. The pre-processed, PNGase F-digested serum and urine samples were labelled with fluorescent tag and then analysed by mass spectrometry, ultra-performance liquid chromatography (UPLC) in combination with exoglycosidase digestions and Glycostore (https://glycostore.org/).

Main results and the role of chance

Glycosylation on total serum and urine glycoproteins and IgG was investigated and differed in endometriosis compared to controls. The N-glycome from the total glycoproteins in serum and urine was also different. The proportion of the galactosylation and sialylation differed between urine and serum IgG and these alterations have an impact on the IgG function. Our preliminary data indicate, that there is an increase in alpha 2–3 sialylation, galactosylation, and fucosylation on urine glycans from endometriosis patients compared to the control pool. Urine is a good source of biomarkers as it can be collected non-invasively. Our group is the first to have developed a protocol for the recovery of N-glycans in urine and to have identified the total N-glycome in urine. The urine N-glycome contains mostly complex N-glycans and also some oligomannosylated and hybrid glycans. Our results may lead to non-invasive biomarkers for the diagnosis of endometriosis and the monitoring of the disease.

Limitations, reasons for caution

The number of participants involved in this basic research is low but this is a pilot study. A larger, validation study, is warranted in the future. Furthermore, the follow-up of treated patients also would be an interesting field of research.

Wider implications of the findings: Glycomics may be a potent source of biomarkers of endometriosis, with a number of glyco-biomarkers already approved by the FDA. Endometriosis-associated glycomic profiles from serum and/or urine glycoproteins may represent viable targets for development of innovative non-invasive or minimally invasive diagnostics in this debilitating disease.

Trial registration number

Not applicable

How do boreal forest soils store carbon?

Boreal forests store a globally significant pool of carbon (C), mainly in tree biomass and soil organic matter (SOM). Although crucial for future climate change predictions, the mechanisms underlying C stabilization are not well understood. Here, recently discovered mechanisms behind SOM stabilization, their level of understanding, interrelations, and future directions in the field are provided. A recently unraveled mechanism behind C stabilization via interaction of root-derived tannins with fungal necromass emphasizing fungal necromass chemistry is brought forth. The long-lasting dogma of the stability of SOM on minerals is challenged and the newest insights from the field of soil fauna and their influence on SOM stabilization are provided. In conclusion, mechanisms unraveled during the last decade are crucial steps forward to draw a holistic view of the main drivers of SOM stabilization.

Root-Derived Proteases as a Plant Tool to Access Soil Organic Nitrogen; Current Stage of Knowledge and Controversies

Anthropogenic deterioration of the global nitrogen (N) cycle emerges mainly from overuse of inorganic N fertilizers in nutrient-limited cropping systems. To counteract a further dysregulation of the N cycle, we need to improve plant nitrogen use efficiency. This aim may be reached via unravelling all plant mechanisms to access soil N, with special attention to the dominating high-molecular-mass N pool. Traditionally, we believe that inorganic N is the only plant-available N pool, however, more recent studies point to acquisition of organic N compounds, i.e., amino acids, short peptides, and proteins. The least known mechanism of plants to increase the N uptake is a direct increase of soil proteolysis via root-derived proteases. This paper provides a review of the knowledge about root-derived proteases and also controversies behind this phenomenon.

Root presence modifies the long-term decomposition dynamics of fungal necromass and the associated microbial communities in a boreal forest

Recent studies have highlighted that dead fungal mycelium represents an important fraction of soil carbon (C) and nitrogen (N) inputs and stocks. Consequently, identifying the microbial communities and the ecological factors that govern the decomposition of fungal necromass will provide critical insight into how fungal organic matter (OM) affects forest soil C and nutrient cycles. Here, we examined the microbial communities colonising fungal necromass during a multiyear decomposition experiment in a boreal forest, which included incubation bags with different mesh sizes to manipulate both plant root and microbial decomposer group access. Necromass-associated bacterial and fungal communities were taxonomically and functionally rich throughout the 30 months of incubation, with increasing abundances of oligotrophic bacteria and root-associated fungi (i.e., ectomycorrhizal, ericoid mycorrhizal and endophytic fungi) in the late stages of decomposition in the mesh bags to which they had access. Necromass-associated β-glucosidase activity was highest at 6 months, while leucine aminopeptidase peptidase was highest at 18 months. Based on an asymptotic decomposition model, root presence was associated with an initial faster rate of fungal necromass decomposition, but resulted in higher amounts of fungal necromass retained at later sampling times. Collectively, these results indicate that microbial community composition and enzyme activities on decomposing fungal necromass remain dynamic years after initial input, and that roots and their associated fungal symbionts result in the slowing of microbial necromass turnover with time.

Are arbuscular-mycorrhizal Alnus incana seedlings more resistant to drought than ectomycorrhizal and nonmycorrhizal ones?

Arbuscular mycorrhizas (AMs) prevail in warm and dry climates and ectomycorrhizas (EMs) in cold and humid climates. We suggest that the fungal symbionts benefit their host plants especially in the corresponding conditions. The hypothesis tested was that AM plants are more drought-resistant than EM or nonmycorrhizal (NM) plants. Grey alder (Alnus incana (L.) Moench) seedlings were inoculated with two species of either AM or EM fungi or none. In one controlled-environment experiment, there was a watering and a drought treatment. Another set of seedlings were not watered until permanent wilting. The AM plants were somewhat smaller than EM and NM, and at the early stage of the drought treatment, the soil-moisture content was slightly higher in the AM pots. Shoot water potential was highest in the AM treatment during severe drought, while stomatal conductance and photosynthesis did not show a mycorrhizal effect. In the lethal-drought set, the AM plants maintained their leaves longer than EM and NM plants, and the AM seedlings survived longer than NM seedlings. Foliar phosphorus and sulfur concentrations remained higher in AM plants than EM or NM, but potassium, copper and iron increased in EM during drought. The root tannin concentration was lower in AM than EM and drought doubled it. Although the difference in drought resistance was not large, the hypothesis was supported by the better performance of AM plants during a severe short-term drought. Sustained phosphorus nutrition during drought in AM plants was a possible reason for this. Moreover, the higher foliar sulfur and lower metal-nutrient concentrations in AM may reflect differences in nutrient uptake or (re)translocation during drought, which merit further research. The much larger tannin concentrations in EM root systems than AM did not appear to protect the EM plants from drought. The differential tannin accumulation in AM and EM plants needs further attention.

Mechanisms of Carbon Sequestration in Highly Organic Ecosystems - Importance of Chemical Ecology

Organic matter decomposition plays a major role in the cycling of carbon (C) and nutrients in terrestrial ecosystems across the globe. Climate change accelerates the decomposition rate to potentially increase the release of greenhouse gases and further enhance global warming in the future. However, fractions of organic matter vary in turnover times and parts are stabilized in soils for longer time periods (C sequestration). Overall, a better understanding of the mechanisms underlying C sequestration is needed for the development of effective mitigation policies to reduce land-based production of greenhouse gases. Known mechanisms of C sequestration include the recalcitrance of C input, interactions with soil minerals, aggregate formation, as well as its regulation via abiotic factors. In this Minireview, we discuss the mechanisms behind C sequestration including the recently emerging significance of biochemical interactions between organic matter inputs that lead to C stabilization.

Plant roots increase both decomposition and stable organic matter formation in boreal forest soil

Boreal forests are ecosystems with low nitrogen (N) availability that store globally significant amounts of carbon (C), mainly in plant biomass and soil organic matter (SOM). Although crucial for future climate change predictions, the mechanisms controlling boreal C and N pools are not well understood. Here, using a three-year field experiment, we compare SOM decomposition and stabilization in the presence of roots, with exclusion of roots but presence of fungal hyphae and with exclusion of both roots and fungal hyphae. Roots accelerate SOM decomposition compared to the root exclusion treatments, but also promote a different soil N economy with higher concentrations of organic soil N compared to inorganic soil N accompanied with the build-up of stable SOM-N. In contrast, root exclusion leads to an inorganic soil N economy (i.e., high level of inorganic N) with reduced stable SOM-N build-up. Based on our findings, we provide a framework on how plant roots affect SOM decomposition and stabilization.

Gross Body Composition Changes in Patients with Cancer of the Uterine Cervix Treated with Irradiation

Gross body composition studies done on a group of 11 women with cervical cancer before and after completion of radiotherapy revealed moderate compositional changes. There was after irradiation a tendency towards weight loss, connected with some increase of relative total body water content and also of its extracellular fraction. The weight loss was due to a decrease of body fat and cell mass, whereas extracellular spaces tended to increase. There was a tendency towards a drop in plasma sodium concentration and an increase of its total content in extracellular water. A significant drop of the potassium serum concentration was observed.

Tannins and Their Complex Interaction with Different Organic Nitrogen Compounds and Enzymes: Old Paradigms versus Recent Advances

Tannins, an abundant group of plant secondary compounds, raise interest in different fields of science, owing to their unique chemical characteristics. In chemical ecology, tannins play a crucial role in plant defense against pathogens, herbivores, and changing environmental conditions. In the food industry and in medicine, tannins are important because of their proven positive effect on human health and disease treatment. Such wide interests fueled studies on tannin chemistry, especially on their flagship ability to precipitate proteins. In this Review, we expand the basic knowledge on tannin chemistry to the newest insights from the field. We focus especially on tannin reactions with different non-protein organic N compounds, as well as the complex interactions of tannins with enzymes, resulting in either an increase or decrease in enzyme activity.

Automated, high-throughput serum glycoprofiling platform

Complex carbohydrates are rapidly becoming excellent biomarker candidates because of their high sensitivity to pathological changes. However, the discovery of clinical glycobiomarkers has been slow, due to the scarcity of high-throughput glycoanalytical workflows that allow rapid glycoprofiling of large clinical sample sets. To generate high-quality quantitative glycomics data in a high-throughput fashion, we have developed a robotized platform for rapid serum-based N-glycan sample preparation. The sample preparation workflow features a fully automated, rapid glycoprotein denaturation followed by sequential enzymatic glycan release, glycan purification on solid-supported hydrazide and fluorescent labelling. This allows accurate glycan quantitation by ultra-high performance liquid chromatography (UPLC). The sample preparation workflow was automated using an eight-channel Hamilton Robotics liquid handling workstation, allowing the preparation of almost 100 samples in 14 hours with excellent reproducibility and thus should greatly facilitate serum-based glyco-biomarker discovery.

IgG N-glycans as potential biomarkers for determining galactose tolerance in Classical Galactosaemia

N-glycan processing and assembly defects have been demonstrated in untreated and partially treated patients with Classical Galactosaemia. These defects may contribute to the ongoing pathophysiology of this disease. The aim of this study was to develop an informative method of studying differential galactose tolerance levels and diet control in individuals with Galactosaemia, compared to the standard biochemical markers. Ten Galactosaemia adults with normal intellectual outcomes were analyzed in the study. Five subjects followed galactose liberalization, increments of 300 mg to 4000 mg/day over 16 weeks, and were compared to five adult Galactosaemia controls on a galactose restricted diet. All study subjects underwent clinical and biochemical monitoring of red blood cell galactose-1-phosphate (RBC Gal-1-P) and urinary galactitol levels. Serum N-glycans were isolated and analyzed by normal phase high-performance liquid chromatography (NP-HPLC) with galactosylation of IgG used as a specific biomarker of galactose tolerance. IgG N-glycan profiles showed consistent individual alterations in response to diet liberalization. The individual profiles were improved for all, but one study subject, at a galactose intake of 1000 mg/day, with decreases in agalactosylated (G0) and increases in digalactosylated (G2) N-glycans. We conclude that IgG N-glycan profiling is an improved method of monitoring variable galactosylation and determining individual galactose tolerance in Galactosaemia compared to the standard methods.

Proteins as nitrogen source for plants: a short story about exudation of proteases by plant roots

Interest in the problem of plant nitrogen nutrition is increasing. Certain plants can use not only inorganic nitrogen, but also intact amino acids and short peptides. According to our studies, the roots of several agricultural and wild-living plants are able to exude proteases and by using them to create a pool of accessible N. This mini-review offers an overview of the problem of protease exudation by plant roots and its potential role in plant nitrogen nutrition.

Degradation of proteins by enzymes exuded by Allium porrum roots - a potentially important strategy for acquiring organic nitrogen by plants

Nitrogen is one of the crucial elements that regulate plant growth and development. It is well-established that plants can acquire nitrogen from soil in the form of low-molecular-mass compounds, namely nitrate and ammonium, but also as amino acids. Nevertheless, nitrogen in the soil occurs mainly as proteins or proteins complexed with other organic compounds. Proteins are believed not to be available to plants. However, there is increasing evidence to suggest that plants can actively participate in proteolysis by exudation of proteases by roots and can obtain nitrogen from digested proteins. To gain insight into the process of organic nitrogen acquisition from proteins by leek roots (Allium porrum L. cv. Bartek), casein, bovine serum albumin and oxidized B-chain of insulin were used; their degradation products, after exposure to plant culture medium, were studied using liquid chromatography-mass spectrometry (LC-MS). Casein was degraded to a great extent, but the level of degradation of bovine serum albumin and the B-chain of insulin was lower. Proteases exuded by roots cleaved proteins, releasing low-molecular-mass peptides that can be taken up by roots. Various peptide fragments produced by digestion of the oxidized B-chain of insulin suggested that endopeptidase, but also exopeptidase activity was present. After identification, proteases were similar to cysteine protease from Arabidopsis thaliana. In conclusion, proteases exuded by roots may have great potential in the plant nitrogen nutrition.

Wheat (Triticum aestivum) seedlings secrete proteases from the roots and, after protein addition, grow well on medium without inorganic nitrogen

This paper reports on the role of proteases secreted by roots in nitrogen capture by plants. The study was conducted on aseptically cultivated wheat seedlings (Triticum aestivum cv. Tacher) obtained from embryos isolated from grains. Seedlings were cultivated for 21 days on deionised water, Murashige Skoog medium (MS), MS without inorganic nitrogen (IN), and MS without IN, in which IN was replaced by casein (0.01%, 0.1% or 1%). Comparison of seedlings grown on these media showed that casein entirely compensated for the lack of inorganic nitrogen in the medium. Shoots and roots of seedlings cultivated on MS medium with this protein had higher fresh weight than those cultivated on MS medium without casein. The increase in fresh weight of seedlings was correlated with casein concentration and proteolytic activity in the medium. In conclusion, wheat that uses proteases secreted by the roots can directly utilise proteins in the medium as a source of nitrogen without prior digestion by microbial proteases and without protein mineralisation. These results suggest the important role of organic nitrogen fertilisers in increasing wheat yield.

The ability of plants to secrete proteases by roots

The aim of our study was to find out if the culture medium of aseptically cultivated seedlings exhibits proteolytic activity and if this event is universal in angiospermous plants. Seedlings of 15 agricultural and wild-living plant species were cultivated for 14days without any addition of nutrients. Our studies showed that roots of higher plants could secrete proteases and that levels of proteolytic activity in the culture medium of individual species (and cultivars of the same species) could be significantly different. The differences between quantities of the secreted proteases were connected neither with the fresh weight of the growing seedlings nor with the surface of the root system. No proteins were required to induce secretion of proteases. The culture medium of a few studied species (Allium porrum, Zea mays, Helianthus annuus) showed the highest proteolytic activity at pH 7. Studies of the influence of standard protease inhibitors showed that examined proteases belong to the cysteine protease family. The results suggest that the apical parts of roots exuded proteases more intensively than mature parts. Our studies suggest that some plant species could develop a strategy to actively increase the level of free amino acids in the soil solution as a source of N. Our results may contribute to studying plant N nutrition in natural ecosystems and to increasing yield after organic fertilization of agricultural species.

Effect of acoustical, visual and tactile reverberation on speech fluency of stutterers

The study presents the comparison of the effects of reverberation transmitted via single and combined channels (auditory, visual and tactile) on the speech of stutterers. The dependence of stuttering intensity and speech velocity upon reverberation time was determined. For all transmission channels the stuttering intensities and the speech velocities decreased with the increase in reverberation time. The results were analyzed statistically by means of the ANOVA method. It was proven that the corrective effects of visual reverberation and tactile reverberation were comparable. Reverberation transmitted via the auditory channel was more effective than when transmitted via the visual or tactile channels. Connecting the visual and tactile channels with the auditory channel has no influence on the effectiveness of reverberation.

Effect of acoustical, visual and tactile echo on speech fluency of stutterers

The study presents the comparison of the effects of echo transmitted via single and combined channels (auditory, visual and tactile) on the speech of stutterers. The dependence of stuttering intensity and speech velocity upon echo delay time was determined. For all transmission channels the stuttering intensities and the speech velocities decreased with the increase in the delay time of the echo. The results were analyzed statistically by means of the ANOVA method. It was proven that the corrective effects of visual echo and tactile echo were comparable. Echo transmitted via the auditory channel was more effective than when transmitted via the visual or tactile channels. The greatest efficiency could be observed by transmitting echo via three connected channels: auditory, visual and tactile. The results obtained show that in stuttering therapy it is justified to use echo transmitted via three connected channels (auditory, visual, tactile).

[Results of chemotherapy of cancer of the stomach]

45 patients with advanced gastric cancer received palliation chemotherapy in the period from October 1975 until December 1985. Remission have been obtained in 9 patients including complete remission in 3 (6.6%) and partial in 6 (8.1%). Mean survival for the whole group has been 11.6 months, in patient with remission 16.4 months and in patients not responding to treatment 5.6 months.

Mass spectrometric investigation of dissociative ionization of toxic gases by electrons at 20-1000 eV

Measurements of the dissociative ionization cross-sections of CO, CO2, NO and N2O molecules for electrons from 20 up to 1000 eV were performed. Total collection of ions was achieved by using a specially constructed cycloidal mass spectrometer, an ion source without slit and a collector with large area. In that open ion source the effusion molecular beam formed by a capillary was crossed by the electron beam. Owing to such parameters of the mass spectrometer the mass discrimination effects were reduced. At the ionization of CO molecules, the ions CO+, C+, O+ and CO2+ were registered; at CO2, the ions CO2+, CO+, O+, C+ and CO2(2)+; at NO, the ions NO+, N+, O+ and NO2+; at N2O, the ions N2O+, NO+, N2+, O+, (N+,N2(2)+) and N2O2+. The relative values of the partial cross-sections were normalized to the absolute total ionization cross-sections obtained by Rapp and Englander-Golden.