Functional characterization and biotechnological applications of exopolysaccharides produced by newly isolated Enterococcus hirae MLG3-25-1.

This study investigated the potential applications of Enterococcus hirae MLG3-25-1 exopolysaccharides (EPS), with a focus on their isolation, identification, production, and functional characteristics. After the bacterial strain was cultured in De Man-Rogosa-Sharpe (MRS) medium containing 1% glucose at 37 °C, the EPS was refined, and the highest yield of 0.85 mg/mL was achieved at the 24-h incubation period. Enterococcus hirae MLG3-25-1 was found to be able to produce EPS. The study explored the microstructure of the EPS, which resembles polysaccharide sheets with smooth surfaces, through scanning electron microscope (SEM) analysis. Through Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analysis, the chemical composition, aligning with glycosidic bond characteristics, has been deciphered. Furthermore, the antimicrobial and antibiofilm activities against pathogenic bacteria, particularly Bacillus sp., demonstrated potential applications in combating antibiotic resistance. The EPS exhibited notable antioxidant activity (89.36% DPPH scavenging), along with high water-holding capacity (575%), emulsifying activity, and flocculation activity, suggesting its potential as a stabilizing agent in the food industry. Overall, this study provides a comprehensive characterization of Enterococcus hirae MLG3-25-1 EPS, emphasizing its diverse applications in antimicrobial, antioxidant, and food-related industries. These findings lay the groundwork for further exploration and utilization of this EPS in various sectors.

Unveiling the presence and genotypic diversity of Giardia duodenalis on large-scale sheep farms: insights from the Henan and Ningxia Regions, China.

BACKGROUND: The parasitic protozoan Giardia duodenalis is an important cause of diarrheal disease in humans and animals that can be spread by fecal-oral transmission through water and the environment, posing a challenge to public health and animal husbandry. Little is known about its impact on large-scale sheep farms in China. In this study we investigated G. duodenalis infection of sheep and contamination of the environment in large-scale sheep farms in two regions of China, Henan and Ningxia. METHODS: A total of 528 fecal samples, 402 environmental samples and 30 water samples were collected from seven large-scale sheep farms, and 88 fecal samples and 13 environmental samples were collected from 12 backyard farms. The presence of G. duodenalis was detected by targeting the ß-giardin (bg) gene, and the assemblage and multilocus genotype of G. duodenalis were investigated by analyzing three genes: bg, glutamate dehydrogenase (gdh) and triphosphate isomerase (tpi). RESULTS: The overall G. duodenalis detection rate was 7.8%, 1.4% and 23.3% in fecal, environmental and water samples, respectively. On the large-scale sheep farms tested, the infection rate of sheep in Henan (13.8%) was found to be significantly higher than that of sheep in Ningxia (4.2%) (P < 0.05). However, the difference between the rates of environmental pollution in Henan (1.9%) and Ningxia (1.0%) was not significant (P > 0.05). Investigations of sheep at different physiological stages revealed that late pregnancy ewes showed the lowest infection rate (1.7%) and that young lambs exhibited the highest (18.8%). Genetic analysis identified G. duodenalis belonging to two assemblages, A and E, with assemblage E being dominant. A total of 27 multilocus genotypes were identified for members of assemblage E. CONCLUSIONS: The results suggest that G. duodenalis is prevalent on large-scale sheep farms in Henan and Ningxia, China, and that there is a risk of environmental contamination. This study is the first comprehensive examination of the presence of G. duodenalis on large-scale sheep farms in China. Challenges posed by G. duodenalis to sheep farms need to be addressed proactively to ensure public health safety.

Molecular epidemiology and multilocus genotyping of Giardia duodenalis in individuals attending major public hospitals in Shiraz, southwestern Iran: A public health concern.

Giardia duodenalis is one of the most common causes of waterborne disease worldwide, and is often associated with outbreaks of diarrhea in areas with poor sanitation and hygiene. This study aimed to assess the prevalence and genetic diversity of G. duodenalis assemblages in individuals attending major public hospitals in Shiraz, southwestern Iran. From August 2022 to May 2023, a total of 614 stool samples from individuals were collected and initially examined for G. duodenalis cysts using parasitological techniques, sucrose flotation, and microscopy. Microscopy-positive samples were validated by SSU-PCR amplification of the parasite DNA. A multilocus genotyping (MLG) scheme, which focused on the triose phosphate isomerase (tpi) and the glutamate dehydrogenase (gdh) genes, was employed for genotyping purposes. G. duodenalis cysts were found in 7.5% (46/614) and 8.5% (52/614) of samples through microscopy and SSU-PCR, respectively. Successful amplification and sequencing results were obtained for 77.3% (17/22) and 45.5% (10/22) of the infected samples at the tpi and gdh loci, respectively. MLG data for the two loci were available for only five samples. Out of the 22 samples genotyped at any loci, 54.5% (12/22) were identified as assemblage A, while 45.5% (10/22) were identified as assemblage B. AII was the most predominant sub-assemblage identified [54.5% (12/22)], followed by BIII [27% (6/22)], discordant BIII/BIV [13.6% (3/22)], and BIV [4.5% (1/22)]. In the present study, no assemblages suited for non-human animal hosts (e.g., C-F) were detected. This suggests that the transmission of human giardiasis in Shiraz is primarily anthroponotic. Further molecular-based analyses are necessary to confirm and expand upon these findings. These analyses will also help determine the presence and public health importance of the parasite in environmental samples, such as drinking water.

Mlg1, a yeast acyltransferase located in ER membranes associated with mitochondria (MAMs), is involved in de novo synthesis and remodelling of phospholipids.

In cells, phospholipids contain acyl chains of variable lengths and saturation, features that affect their functions. Their de novo synthesis in the endoplasmic reticulum takes place via the cytidine diphosphate diacylglycerol (CDP-DAG) and Kennedy pathways, which are conserved in eukaryotes. PA is a key intermediate for all phospholipids (PI, PIPs, PS, PE, PC, PG and CL). The de novo synthesis of PA occurs by acylation of glycerophosphate leading to the synthesis of 1-acyl lysoPA and subsequent acylation of 1-acyl lysoPA at the sn-2 position. Using membranes from Escherichia coli overexpressing MLG1, we showed that the yeast gene MLG1 encodes an acyltransferase, leading specifically to the synthesis of PA from 1-acyl lysoPA. Moreover, after their de novo synthesis, phospholipids can be remodelled by acyl exchange with one and/or two acyl chains exchanged at the sn-1 and/or sn-2 position. Based on shotgun lipidomics of the reference and mlg1Δ strains, as well as biochemical assays for acyltransferase activities, we identified an additional remodelling activity for Mlg1p, namely, incorporation of palmitic acid into the sn-1 position of PS and PE. By using confocal microscopy and subcellular fractionation, we also found that this acyltransferase is located in ER membranes associated with mitochondria, a finding that highlights the importance of these organelles in the global cellular metabolism of lipids.

Quantification of Mixed-Linkage ß-Glucan (MLG) in Bacteria.

Prokaryotes are known to produce and secrete a broad range of biopolymers with a high functional and structural heterogeneity, often with critical duties in the bacterial physiology and ecology. Among these, exopolysaccharides (EPS) play relevant roles in the interaction of bacteria with eukaryotic hosts. EPS can help to colonize the host and assist in bacterial survival, making this interaction more robust by facilitating the formation of structured biofilms. In addition, they are often key molecules in the specific recognition mechanisms involved in both beneficial and pathogenic bacteria-host interactions. A novel EPS known as MLG (Mixed-Linkage ß-Glucan) was recently discovered in rhizobia, where it participates in bacterial aggregation and biofilm formation and is required for efficient attachment to the roots of their legume host plants. MLG is the first and, so far, the only reported linear Mixed-Linkage ß-glucan in bacteria, containing a perfect alternation of ß (1 â†’ 3) and ß (1 â†’ 4) bonds. A phylogenetic study of MLG biosynthetic genes suggests that far from being exclusive of rhizobia, different soil and plant-associated bacteria likely produce MLG, adding this novel polymer to the plethora of surface polysaccharides that help bacteria thrive in the changing environment and to establish successful interactions with their hosts.In this work, a quantification method for MLG is proposed. It relays on the hydrolysis of MLG by a specific enzyme (lichenase), and the subsequent quantification of the released disaccharide (laminaribiose) by the phenol-sulfuric acid method. The protocol has been set up and optimized for its use in 96-well plates, which makes it suitable for high-throughput screening (HTS) approaches. This method stands out by its fast processing, technical simplicity, and capability to handle multiple samples and biological replicates at a time.

Genotyping and epidemiological distribution of diarrhea-causing isolates of Giardia duodenalis in southeastern part of West Bengal, India.

The prevalence and genetic diversity of the protozoan pathogen Giardia duodenalis have been extensively studied worldwide. There is currently a lack of data regarding the genetic variability of the organism in eastern India. Understanding the circulating genotypes and associated risk factors is crucial for effective planning and implementing control measures. Therefore, the objective of the study was to conduct an epidemiological study to determine the prevalence and identify the various genotypes present. This survey adds to our knowledge on the occurrence and distribution of Giardia genotypes in the studied region. The overall prevalence was found to be 6.8%. This parasitic infection was significantly associated with two age groups, i.e., >0-5 years and >5-12 years. Using a multilocus genotyping method, we genotyped 52 human Giardia isolates that were obtained from diarrheal patients. Two distinct assemblages were found in the population-30.8% belonged to assemblage A; 63.5% belonged to assemblage B, prevalent in the population; and 5.7% belonged to a combined assemblage A+B. Sub-assemblage AII was found in 17.3% of the cases, followed by sub-assemblage AI (13.5%). High levels of genetic diversity were found within the population of assemblage B undergoing balancing selection. Overall, the high prevalence of the parasite observed, particularly among children, raises a major concern and necessitates implementation of robust control measures. Furthermore, we report the presence of numerous unique genotypes, circulating in this limited geographical boundary, which can be useful dataset for future studies.

Utilization of dietary mixed-linkage ß-glucans by the Firmicute Blautia producta.

The ß-glucans are structurally varied, naturally occurring components of the cell walls, and storage materials of a variety of plant and microbial species. In the human diet, mixed-linkage glucans [MLG - ß-(1,3/4)-glucans] influence the gut microbiome and the host immune system. Although consumed daily, the molecular mechanism by which human gut Gram-positive bacteria utilize MLG largely remains unknown. In this study, we used Blautia producta ATCC 27340 as a model organism to develop an understanding of MLG utilization. B. producta encodes a gene locus comprising a multi-modular cell-anchored endo-glucanase (BpGH16MLG), an ABC transporter, and a glycoside phosphorylase (BpGH94MLG) for utilizing MLG, as evidenced by the upregulation of expression of the enzyme- and solute binding protein (SBP)-encoding genes in this cluster when the organism is grown on MLG. We determined that recombinant BpGH16MLG cleaved various types of ß-glucan, generating oligosaccharides suitable for cellular uptake by B. producta. Cytoplasmic digestion of these oligosaccharides is then performed by recombinant BpGH94MLG and ß-glucosidases (BpGH3-AR8MLG and BpGH3-X62MLG). Using targeted deletion, we demonstrated BpSBPMLG is essential for B. producta growth on barley ß-glucan. Furthermore, we revealed that beneficial bacteria, such as Roseburia faecis JCM 17581T, Bifidobacterium pseudocatenulatum JCM 1200T, Bifidobacterium adolescentis JCM 1275T, and Bifidobacterium bifidum JCM 1254, can also utilize oligosaccharides resulting from the action of BpGH16MLG. Disentangling the ß-glucan utilizing the capability of B. producta provides a rational basis on which to consider the probiotic potential of this class of organism.

Mixed-Linkage Glucan Is the Main Carbohydrate Source and Starch Is an Alternative Source during Brachypodium Grain Germination.

Seeds of the model grass Brachypodium distachyon are unusual because they contain very little starch and high levels of mixed-linkage glucan (MLG) accumulated in thick cell walls. It was suggested that MLG might supplement starch as a storage carbohydrate and may be mobilised during germination. In this work, we observed massive degradation of MLG during germination in both endosperm and nucellar epidermis. The enzymes responsible for the MLG degradation were identified in germinated grains and characterized using heterologous expression. By using mutants targeting MLG biosynthesis genes, we showed that the expression level of genes coding for MLG and starch-degrading enzymes was modified in the germinated grains of knocked-out cslf6 mutants depleted in MLG but with higher starch content. Our results suggest a substrate-dependent regulation of the storage sugars during germination. These overall results demonstrated the function of MLG as the main carbohydrate source during germination of Brachypodium grain. More astonishingly, cslf6 Brachypodium mutants are able to adapt their metabolism to the lack of MLG by modifying the energy source for germination and the expression of genes dedicated for its use.

Preparation and tribological properties of multi-layer graphene/silicon dioxide composites-based solid lubricant coatings at elevated temperatures.

The solid lubricating coatings have an important role in hot metal forming. However, traditional lubricants cannot be applied to the harsh working conditions. In this investigation, the novel solid lubricant coatings including multi-layer graphene (MLG)/silicon dioxide (SiO2) composites and sodium metaphosphate phosphate were prepared. The high-temperature tribological properties of the solid lubricant coatings were investigated by friction and wear tester. The experimental results showed that SiO2 nanoparticles were evenly grafted by sol-gel method on the surface of MLG, forming MLG/SiO2 composites. MLG/SiO2 composites presented excellent thermal stability at 800°C. In the range of 400-800°C, the average coefficients of friction (COFs) were decreased from 0.3936 to 0.3663, and then increased from 0.3663 to 0.4226. Based on the analysis of wear scar, the lubrication mechanisms of the solid lubricating coatings were proposed. The low interlayer shear of MLG and the ball bearing of SiO2 nanoparticles are the main reason for the reduction of COFs. In addition, the tribo-chemical reaction film formed on the frictional interface could protect the contact surfaces from severe damage. The findings would be beneficial for developing novel lubricants for hot metal forming process.

Modeling and Optimization of Sensitivity and Creep for Multi-Component Sensing Materials.

Pressure sensors urgently need high-performance sensing materials in order to be developed further. Sensitivity and creep are regarded as two key indices for assessing a sensor's performance. For the design and optimization of sensing materials, an accurate estimation of the impact of several parameters on sensitivity and creep is essential. In this study, sensitivity and creep were predicted using the response surface methodology (RSM) and support vector regression (SVR), respectively. The input parameters were the concentrations of nickel (Ni) particles, multiwalled carbon nanotubes (MWCNTs), and multilayer graphene (MLG), as well as the magnetic field intensity (B). According to statistical measures, the SVR model exhibited a greater level of predictability and accuracy. The non-dominated sorting genetic-II algorithm (NSGA-II) was used to generate the Pareto-optimal fronts, and decision-making was used to determine the final optimal solution. With these conditions, the optimized results revealed an improved performance compared to the earlier study, with an average sensitivity of 0.059 kPa-1 in the pressure range of 0-16 kPa and a creep of 0.0325, which showed better sensitivity in a wider range compared to previous work. The theoretical sensitivity and creep were relatively similar to the actual values, with relative deviations of 0.317% and 0.307% after simulation and experimental verification. Future research for transducer performance optimization can make use of the provided methodology because it is representative.

Isolated Adductor Magnus Injuries in Athletes: A Case Series.

Background: Little is known about injuries to the adductor magnus (AM) muscle and how to manage them. Purpose: To describe the injury mechanisms of the AM and its histoarchitecture, clinical characteristics, and imaging features in elite athletes. Study Design: Case series; Level of evidence, 4. Methods: A total of 11 competitive athletes with an AM injury were included in the study. Each case was clinically assessed, and the diagnosis and classification were made by magnetic resonance imaging (MRI) according to the British Athletics Muscle Injury Classification (BAMIC) and mechanism, location, grade, and reinjury (MLG-R) classification. A 1-year follow-up was performed, and return-to-play (RTP) time was recorded. Results: Different mechanisms of injury were found; most of the athletes (10/11) had flexion and internal rotation of the hip with extension or slight flexion of the knee. Symptoms consisted of pain in the posteromedial (7/11) or medial (4/11) thigh during adduction and flexion of the knee. Clinically, there was a suspicion of an injury to the AM in only 3 athletes. According to MRI, 5 lesions were located in the ischiocondylar portion (3 in the proximal and 2 in the distal myoconnective junction) and 6 in the pubofemoral portion (4 in the distal and 2 in the proximal myoconnective junction). Most of the ischiocondylar lesions were myotendinous (3/5), and most of the pubofemoral lesions were myofascial (5/6). The BAMIC and MLG-R classification coincided in distinguishing injuries of moderate and mild severity. The management was nonoperative in all cases. The mean RTP time was 14 days (range, 0-35 days) and was longer in the ischiocondylar cases than in the pubofemoral cases (21 vs 8 days, respectively). Only 1 recurrence, at <10 months, was recorded. Conclusion: Posteromedial thigh pain after an eccentric contraction during forced adduction of the thigh from hip internal rotation should raise a suspicion of AM lesions. The identification of the affected portion was possible on MRI. An injury in the ischiocondylar portion entailed a longer RTP time than an injury in the pubofemoral portion.

MedDRA Labeling Groupings to Improve Safety Communication in Product Labels.

The granularity and structure of the International Council for Harmonisation's (ICH) Medical Dictionary for Regulatory Activities (MedDRA) are useful for precise coding of adverse events (AEs) for data analysis. In product labeling for healthcare practitioners, however, the granularity of MedDRA Preferred Terms (PTs) can obscure the communication of adverse reactions (ARs). Driven by a focus on patient safety, business needs, and regulatory guidance, many sponsors and regulators have begun to develop institution-specific approaches to clustering similar AR terms in medical product prescribing information on a product-by-product basis. However, there are no agreed upon conventions that describe which AR terms may be appropriate to group together. In order to improve safety communication to patients and healthcare providers, there is an urgent need for a harmonized international approach to the creation and use of groups of MedDRA PTs which we refer to as "MedDRA Labeling Groupings (MLGs)" in medical product prescribing information. Given its long-standing contributions towards the design of Standardised MedDRA Queries (SMQs), the Council for International Organizations of Medical Sciences (CIOMS) convened an Expert Working Group (EWG) with involvement of multiple major stakeholders to produce a consensus document on principles and points to consider in the development of MLGs. The CIOMS MLG EWG identified variations in grouping of MedDRA PTs in product labels, and in the current document, proposes a strategy for improving the communication of drug safety labeling. It is envisaged that the use of these consensus recommendations would be voluntary and applied to product labels in a manner that is consistent with existing regulatory frameworks.

Fabrication and Characterization of Visible to Near-Infrared Photodetector Based on Multilayer Graphene/Mg2Si/Si Heterojunction.

In this investigation, p-Mg2Si/n-Si heterojunction photodetector (PD) is fabricated by magnetron sputtering and low vacuum annealing in the absence of argon or nitrogen atmosphere. Multilayer Graphene (MLG)/Mg2Si/Si heterojunction PD is first fabricated by transferring MLG to Mg2Si/Si heterojunction substrate using the suspended self-help transfer MLG method. After characterizing the phase composition, morphology and detection properties of Mg2Si/Si and MLG/Mg2Si/Si heterojunction PDs, the successful fabrication of the Mg2Si/Si and MLG/Mg2Si/Si heterojunction PDs are confirmed and some detection capabilities are realized. Compared with the Mg2Si/Si heterojunction PD, the light absorption and the ability to effectively separate and transfer photogenerated carriers of MLG/Mg2Si/Si heterojunction PD are improved. The responsivity, external quantum efficiency (EQE), noise equivalent power (NEP), detectivity (D*), on/off ratio and other detection properties are enhanced. The peak responsivity and EQE of the MLG/Mg2Si/Si heterojunction PD are 23.7 mA/W and 2.75%, respectively, which are better than the previous 1-10 mA/W and 2.3%. The results illustrate that the fabrication technology of introducing MLG to regulate the detection properties of the Mg2Si/Si heterojunction PD is feasible. In addition, this study reveals the potential of MLG to enhance the detection properties of optoelectronic devices, broadens the application prospect of the Mg2Si/Si-based heterojunction PDs and provides a direction for the regulation of optoelectronic devices.

The Role of Two Linear ß-Glucans Activated by c-di-GMP in Rhizobium etli CFN42.

Bacterial exopolysaccharides (EPS) have been implicated in a variety of functions that assist in bacterial survival, colonization, and host-microbe interactions. Among them, bacterial linear ß-glucans are polysaccharides formed by D-glucose units linked by ß-glycosidic bonds, which include curdlan, cellulose, and the new described Mixed Linkage ß-Glucan (MLG). Bis-(3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a universal bacterial second messenger that usually promote EPS production. Here, we report Rhizobium etli as the first bacterium capable of producing cellulose and MLG. Significant amounts of these two ß-glucans are not produced under free-living laboratory conditions, but their production is triggered upon elevation of intracellular c-di-GMP levels, both contributing to Congo red (CR+) and Calcofluor (CF+) phenotypes. Cellulose turned out to be more relevant for free-living phenotypes promoting flocculation and biofilm formation under high c-di-GMP conditions. None of these two EPS are essential for attachment to roots of Phaseolus vulgaris, neither for nodulation nor for symbiotic nitrogen fixation. However, both ß-glucans separately contribute to the fitness of interaction between R. etli and its host. Overproduction of these ß-glucans, particularly cellulose, appears detrimental for symbiosis. This indicates that their activation by c-di-GMP must be strictly regulated in time and space and should be controlled by different, yet unknown, regulatory pathways.

Near-Isogenic Barley Lines Show Enhanced Susceptibility to Powdery Mildew Infection Following High-Temperature Stress.

Barley cultivation is adversely affected by high-temperature stress, which may modulate plant defense responses to pathogens such as barley powdery mildew (Blumeria graminis f. sp. hordei, Bgh). Earlier research focused mainly on the influence of short-term heat stress (heat shock) of barley on Bgh infection. In this study, our aim was to investigate the effects of both short- and long-term heat stress (35 °C from 30 s to 5 days) on Bgh infection in the barley cultivar Ingrid and its near-isogenic lines containing different powdery mildew resistance genes (Mla12, Mlg, and mlo5) by analyzing symptom severity and Bgh biomass with RT-qPCR. The expression of selected barley defense genes (BAX inhibitor-1, Pathogenesis- related protein-1b, Respiratory burst oxidase homologue F2, and Heat shock protein 90-1) was also monitored in plants previously exposed to heat stress followed by inoculation with Bgh. We demonstrated that pre-exposure to short- and long-term heat stress negatively affects the resistance of all resistant lines manifested by the appearance of powdery mildew symptoms and increased Bgh biomass. Furthermore, prolonged heat stress (48 and 120 h) enhanced both Bgh symptoms and biomass in susceptible wild-type Ingrid. Heat stress suppressed and delayed early defense gene activation in resistant lines, which is a possible reason why resistant barley became partially susceptible to Bgh.

Graphene with Ni-Grid as Semitransparent Electrode for Bulk Heterojunction Solar Cells (BHJ-SCs).

In this work, we present the fabrication and characterization of bulk-heterojunction solar cells on monolayer graphene (MLG) with nickel-grids (Ni-grid) as semitransparent conductive electrode. The electrodes showed a maximum transmittance of 90% (calculated in 300-800 nm range) and a sheet resistance down to 35 Ω/□. On these new anodes, we fabricated TCO free BHJ-SCs using PTB7 blended with PC70BM fullerene derivative as active layer. The best device exhibited a power conversion efficiency (PCE) of 4.2% in direct configuration and 3.6% in inverted configuration. The reference solar cell, realized on the ITO glass substrate, achieved a PCE of 6.1% and 6.7% in direct and inverted configuration respectively; for comparison we also tested OSCs only with simple Ni-grid as semitransparent and conductive electrode, obtaining a low PCE of 0.7%. The proposed approach to realize graphene-based electrodes could be a possible route to reduce the overall impact of the sheet resistance of this type of electrodes allowing their use in several optoelectronic devices.

Giardia duodenalis in Wildlife: Exploring Genotype Diversity in Italy and across Europe.

Fragmented data are so far available on genotype diversity of G. duodenalis in wildlife in different countries in Europe, in particular, in Italy. In the present study, G. duodenalis sequences obtained from different Italian wild animals [12 porcupines (Hystrix cristata), 4 wild boars (Sus scrofa), 1 wolf (Canis lupus italicus), 6 Alpine chamois (Rupicapra rupicapra rupicapra)] were compared with those available from wild host species in Europe to add new data on the geographic distribution of Giardia assemblages/sub-assemblages and their transmission patterns among natural hosts. Thirty-eight sequences were obtained by MLG analysis (SSU-rRNA, bg, gdh, and tpi genes) and subsequently compared by phylogenetic and network analyses with those from wild species monitored in the last decades in Europe. The results revealed the presence of potentially zoonotic (A-AI, A-AII from wild boar; B from porcupine) and host-adapted (D from wolf; E, A-AIII from chamois) assemblages and sub-assemblages and represent the first report for Italian wild boar. The analysis did not find any evidence of spatial or host segregation for specific genetic variants, mostly shared between different hosts from different European countries. However, conflicting evidence was found in genotypic assignment, advocating for data improvement and new genomic approaches.

Genome-Wide Association Mapping of Mixed Linkage (1,3;1,4)-ß-Glucan and Starch Contents in Rice Whole Grain.

The glucan content of rice is a key factor defining its nutritional and economic value. Starch and its derivatives have many industrial applications such as in fuel and material production. Non-starch glucans such as (1,3;1,4)-ß-D-glucan (mixed-linkage ß-glucan, MLG) have many benefits in human health, including lowering cholesterol, boosting the immune system, and modulating the gut microbiome. In this study, the genetic variability of MLG and starch contents were analyzed in rice (Oryza sativa L.) whole grain, by performing a new quantitative analysis of the polysaccharide content of rice grains. The 197 rice accessions investigated had an average MLG content of 252 µg/mg, which was negatively correlated with the grain starch content. A new genome-wide association study revealed seven significant quantitative trait loci (QTLs) associated with the MLG content and two QTLs associated with the starch content in rice whole grain. Novel genes associated with the MLG content were a hexose transporter and anthocyanidin 5,3-O-glucosyltransferase. Also, the novel gene associated with the starch content was a nodulin-like domain. The data pave the way for a better understanding of the genes involved in determining both MLG and starch contents in rice grains and should facilitate future plant breeding programs.

Advances in Cell Wall Matrix Research with a Focus on Mixed-Linkage Glucan.

Mixed ß(1,3;1,4)-linkage glucan (MLG) is commonly found in the monocot lineage, at particularly high levels in the Poaceae family, but also in the evolutionally distant genus, Equisetum. MLG has several properties that make it unique from other plant cell wall polysaccharides. It consists of ß1,4-linked polymers of glucose interspersed with ß1,3-linkages, but the presence of ß1,3-linkages provides quite different physical properties compared to its closest form of the cell wall component, cellulose. The mechanisms of MLG biosynthesis have been investigated to understand whether single or multiple enzymes are required to build mixed linkages in the glucan chain. Currently, MLG synthesis by a single enzyme is supported by mutagenesis analyses of cellulose synthase-like F6, the major MLG synthase, but further investigation is needed to gather mechanistic insights. Because of transient accumulation of MLG in elongating cells and vegetative tissues, several hypotheses have been proposed to explain the role of MLG in the plant cell wall. Studies have been carried out to identify gene expression regulators during development and light cycles as well as enzymes involved in MLG organization in the cell wall. A role of MLG as a storage molecule in grains is evident, but the role of MLG in vegetative tissues is still not well understood. Characterization of a cell wall component is difficult due to the complex heterogeneity of the plant cell wall. However, as detailed in this review, recent exciting research has made significant impacts in the understanding of MLG biology in plants.

Interactions between Cellulose and (1,3;1,4)-ß-glucans and Arabinoxylans in the Regenerating Wall of Suspension Culture Cells of the Ryegrass Lolium multiflorum.

Plant cell walls (PCWs) form the outer barrier of cells that give the plant strength and directly interact with the environment and other cells in the plant. PCWs are composed of several polysaccharides, of which cellulose forms the main fibrillar network. Enmeshed between these fibrils of cellulose are non-cellulosic polysaccharides (NCPs), pectins, and proteins. This study investigates the sequence, timing, patterning, and architecture of cell wall polysaccharide regeneration in suspension culture cells (SCC) of the grass species Lolium multiflorum (Lolium). Confocal, superresolution, and electron microscopies were used in combination with cytochemical labeling to investigate polysaccharide deposition in SCC after protoplasting. Cellulose was the first polysaccharide observed, followed shortly thereafter by (1,3;1,4)-ß-glucan, which is also known as mixed-linkage glucan (MLG), arabinoxylan (AX), and callose. Cellulose formed fibrils with AX and produced a filamentous-like network, whereas MLG formed punctate patches. Using colocalization analysis, cellulose and AX were shown to interact during early stages of wall generation, but this interaction reduced over time as the wall matured. AX and MLG interactions increased slightly over time, but cellulose and MLG were not seen to interact. Callose initially formed patches that were randomly positioned on the protoplast surface. There was no consistency in size or location over time. The architecture observed via superresolution microscopy showed similarities to the biophysical maps produced using atomic force microscopy and can give insight into the role of polysaccharides in PCWs.