Mucilage extracted from Chilean papaya seeds is enriched with homogalacturonan domains.

Chilean papaya, also known as mountain papaya (Vasconcellea pubescens), is a fruit valued for its nutritional value and pleasant fragrance. The oblong fruit, featuring five ridges and a seed-filled mucilage cavity, is typically consumed cooked due to its high protease content. The mucilage and the seeds are usually discarded as byproducts. This study analyzed the biochemical composition of mountain papaya seed mucilage using methods such as HPAEC and immunolabeling. Results revealed that papaya seeds yield nearly 20% of their weight in mucilage polysaccharides, which can be separated into soluble and adherent layers. The mucilage exhibited a high proportion of acidic sugars, indicating that homogalacturonan (HG) is the predominant domain. It also contained other domains like rhamnogalacturonan-I (RG-I) and hemicelluloses, predominantly xyloglucan. The HG-rich mucilage, currently considered waste, emerges as a promising source of polysaccharides, indicating its multifaceted utility in various industrial applications.

A novel pectin methylesterase inhibitor, PMEI3, in common bean suggests a key role of pectin methylesterification in Pseudomonas resistance.

The mechanisms underlying susceptibility to and defense against Pseudomonas syringae (Pph) of the common bean (Phaseolus vulgaris) have not yet been clarified. To investigate these, 15-day-old plants of the variety Riñón were infected with Pph and the transcriptomic changes at 2 h and 9 h post-infection were analysed. RNA-seq analysis showed an up-regulation of genes involved in defense/signaling at 2 h, most of them being down-regulated at 9 h, suggesting that Pph inhibits the transcriptomic reprogramming of the plant. This trend was also observed in the modulation of 101 cell wall-related genes. Cell wall composition changes at early stages of Pph infection were associated with homogalacturonan methylation and the formation of egg boxes. Among the cell wall genes modulated, a pectin methylesterase inhibitor 3 (PvPMEI3) gene, closely related to AtPMEI3, was detected. PvPMEI3 protein was located in the apoplast and its pectin methylesterase inhibitory activity was demonstrated. PvPMEI3 seems to be a good candidate to play a key role in Pph infection, which was supported by analysis of an Arabidopsis pmei3 mutant, which showed susceptibility to Pph, in contrast to resistant Arabidopsis Col-0 plants. These results indicate a key role of the degree of pectin methylesterification in host resistance to Pph during the first steps of the attack.

Intraoperative immediate strength recovery following lacertus fibrosus release in patients with proximal median nerve compression at the elbow.

PURPOSE: In the literature, we find that patients with lacertus syndrome (LS), proximal median nerve compression at the elbow, present subjective improvement of thumb, and index flexion strength after lacertus fibrosus (LF) release. The aim of this study is to objectively evaluate the immediate change in intraoperative flexion strength after LF release. METHOD: We retrospectively reviewed prospectively collected data of a cohort of 24 patients with a double crush syndrome of the median nerve with no response to conservative treatment. All patients had surgery with LF and carpal tunnel release (CTR) under wide-awake local anaesthesia and no tourniquet (WALANT) and were evaluated intraoperatively with a dynamometer immediately before and after LF release. Flexor digitorum profundus of the second finger (FDP2) and Flexor pollicis longus (FPL) were tested in peak strength to failure. The primary outcome was the percentage of change in strength before and after the release in both assessed muscles. CTR was done after evaluating the change in flexor strength. RESULTS: A percentage of 79.2 women with an average age of 43.3 years. The average strength of FDP2 before LF release was 15.5 pounds (lbs.) (7.0 kg) (SD, 7.2 lbs (3.3 kg)) and 27.1 lbs. (12.2 kg) (SD, 7.1 lbs. (3.2 kg)) after LF release, which corresponds to a 96% (SD, 70%) change in strength (p=0.000). For FPL, the average pre-release strength was 17.7 lbs. (8.0kg) (SD, 4.8 lbs. (2.2 kg)) and 27.4 lbs. (12.4 kg) (SD, 5.2 lbs. (2.4 kg)) post-release, this corresponded to a 65% (SD, 38%) change in strength (p=0.000). CONCLUSIONS: Peak strength to failure in FDP2 and FPL has an immediate significant recovery after LF surgical release in patients with Lacertus syndrome. LEVEL OF EVIDENCE: IV, retrospective study.

GoSAMTs are required for pectin methyl-esterification and mucilage release in seed coat epidermal cells.

Introduction: GoSAMTs play a role in the methylation of polysaccharides synthesized by the Golgi. Pectin homogalacturonan (HG) methyl-esterification is essential for the proper function of this polysaccharide in cell walls. In order to better understand the role of GoSAMTs in HG biosynthesis, we analyzed mucilage methyl-esterification in gosamt mutants. Methods: To determine the function of GoSAMT1 and GoSAMT2 in HG methyl-esterification we utilized epidermal cells of seed coats, as these structures produce mucilage, which is a pectic matrix. We evaluated differences in seed surface morphology and quantified mucilage release. We measured methanol release, and used antibodies and confocal microscopy to analyze HG methyl-esterification in mucilage. Results: We observed morphological differences on the seed surface and delayed, uneven mucilage release in gosamt1-1gosamt2-1 double mutants. We also found changes in the distal wall length indicating abnormal cell wall breakage in this double mutant. Using methanol release and immunolabeling, we confirmed that GoSAMT1 and GoSAMT2 are involved in HG methyl-esterification in mucilage. However, we did not find evidence of decreasing HG in the gosamt mutants. Confocal microscopy analyses detected different patterns in the adherent mucilage and a greater number of low-methyl-esterified domains near the seed coat surface, which correlates with a greater number of "egg-box" structures in this region. We also detected a shift in the partitioning between the Rhamnogalacturonan-I soluble and adherent layers of the double mutant, which correlated with increased amounts of arabinose and arabinogalactan-protein in the adherent mucilage. Discussion: The results show that the HG synthesized in gosamt mutant plants is less methyl esterified, resulting in more egg-box structures, which stiffen the cell walls in epidermal cells and change the rheological properties of the seed surface. The increased amounts of arabinose and arabinogalactan-protein in adherent mucilage, also suggests that compensation mechanisms were triggered in the gosamt mutants.

[Prevalence and lethality of interstitial pulmonary diseases in the Region of Los Ríos, Chile]. / Prevalencia y letalidad de enfermedades pulmonares intersticiales en la Región de Los Ríos, Chile.

BACKGROUND: Idiopathic Pulmonary Fibrosis (IPF) is a subtype of interstitial lung disease (ILD) that significantly affects people's quality of life, whose prevalence and mortality has increased. AIM: To determine the prevalence and lethality of ILD in the Los Ríos Region between the years 2018 and 2019. MATERIAL AND METHODS: Review of a database of all patients attended at an outpatient clinic of the regional hospital. Those patients with the diagnosis of ILD and seen between 2018 and 2019 were selected. Mortality and its causes were verified with death certificates. RESULTS: In the study period, 339 cases with ILD, aged 71 ± 10 years (64% women) were identified. The calculated ILD prevalence was 84 cases per 100,000 inhabitants, with a higher predominancy in Futrono and Paillaco communes. IPF and Connective Tissue Diseases were the predominant subtypes. Overall lethality was 18%, with more deaths among patients with IPF (n = 31). CONCLUSIONS: In the Los Ríos Region, ILDs have a relevant prevalence and lethality.

Prevalencia y letalidad de enfermedades pulmonares intersticiales en la Región de Los Ríos, Chile / Prevalence and lethality of interstitial pulmonary diseases in the Region of Los Ríos, Chile

BACKGROUND: Idiopathic Pulmonary Fibrosis (IPF) is a subtype of interstitial lung disease (ILD) that significantly affects people's quality of life, whose prevalence and mortality has increased. AIM: To determine the prevalence and lethality of ILD in the Los Ríos Region between the years 2018 and 2019. MATERIAL AND METHODS: Review of a database of all patients attended at an outpatient clinic of the regional hospital. Those patients with the diagnosis of ILD and seen between 2018 and 2019 were selected. Mortality and its causes were verified with death certificates. RESULTS: In the study period, 339 cases with ILD, aged 71 ± 10 years (64% women) were identified. The calculated ILD prevalence was 84 cases per 100,000 inhabitants, with a higher predominancy in Futrono and Paillaco communes. IPF and Connective Tissue Diseases were the predominant subtypes. Overall lethality was 18%, with more deaths among patients with IPF (n = 31). CONCLUSIONS: In the Los Ríos Region, ILDs have a relevant prevalence and lethality.

Transmetalation Reactions Triggered by Electron Transfer between Organocopper Complexes.

[Cu(bipy)(C6F5)] reacts with most aryl iodides to form heterobiphenyls by cross-coupling, but when Rf-I is used (Rf = 3,5-dicholoro-2,4,6-trifluorophenyl), homocoupling products are also formed. Kinetic studies suggest that, for the homocoupling reaction, a mechanism based on transmetalation from [Cu(bipy)(C6F5)] to Cu(III) intermediates formed in the oxidative addition step is at work. Density functional theory calculations show that the interaction between these Cu(III) species and the starting Cu(I) complex involves a Cu(I)-Cu(III) electron transfer concerted with the formation of an iodine bridge between the metals and that a fast transmetalation takes place in a dimer in a triplet state between two Cu(II) units.

Transport of UDP-rhamnose by URGT2, URGT4, and URGT6 modulates rhamnogalacturonan-I length.

Rhamnogalacturonan-I biosynthesis occurs in the lumen of the Golgi apparatus, a compartment where UDP-Rhamnose and UDP-Galacturonic Acid are the main substrates for synthesis of the backbone polymer of pectin. Recent studies showed that UDP-Rha is transported from the cytosol into the Golgi apparatus by a family of six UDP-rhamnose/UDP-galactose transporters (URGT1-6). In this study, analysis of adherent and soluble mucilage (SM) of Arabidopsis thaliana seeds revealed distinct roles of URGT2, URGT4, and URGT6 in mucilage biosynthesis. Characterization of SM polymer size showed shorter chains in the urgt2 urgt4 and urgt2 urgt4 urgt6 mutants, suggesting that URGT2 and URGT4 are mainly involved in Rhamnogalacturonan-I (RG-I) elongation. Meanwhile, mutants in urgt6 exhibited changes only in adherent mucilage (AM). Surprisingly, the estimated number of RG-I polymer chains present in urgt2 urgt4 and urgt2 urgt4 urgt6 mutants was higher than in wild-type. Interestingly, the increased number of shorter RG-I chains was accompanied by an increased amount of xylan. In the urgt mutants, expression analysis of other genes involved in mucilage biosynthesis showed some compensation. Studies of mutants of transcription factors regulating mucilage formation indicated that URGT2, URGT4, and URGT6 are likely part of a gene network controlled by these regulators and involved in RG-I synthesis. These results suggest that URGT2, URGT4, and URGT6 play different roles in the biosynthesis of mucilage, and the lack of all three affects the production of shorter RG-I polymers and longer xylan domains.

Computational Analysis on the Pd-Catalyzed C-N Coupling of Ammonia with Aryl Bromides Using a Chelate Phosphine Ligand.

The Buchwald-Hartwig amination of arylhalides with the Pd-Josiphos complex is a very useful process for the generation of primary amines using ammonia as a reactant. Density-functional theory (DFT) calculations are carried out to examine the reaction mechanism for this process. Although the general mechanism for the C-N cross-coupling reaction is known, there are still some open questions regarding the effect of a chelate phosphine ligand and the role of the base in the process. Reaction pathways involving the release of one of the arms of the phosphine ligand are compared with those where the chelate phosphine remains fully coordinated. Conformational analysis for the complex with the open chelate phosphine is required to properly evaluate the proposed pathways. The role played by the added base (t-BuO-) as a possible ligand or just as a base was also evaluated. The understanding of all of these aspects allowed us to propose a complete reaction mechanism for the Pd-catalyzed C-N coupling of arylhalides with ammonia using the chelate Josiphos ligand.

Functional Interchangeability of Nucleotide Sugar Transporters URGT1 and URGT2 Reveals That urgt1 and urgt2 Cell Wall Chemotypes Depend on Their Spatio-Temporal Expression.

Nucleotide sugar transporters (NSTs) are Golgi-localized proteins that play a role in polysaccharide biosynthesis by transporting substrates (nucleotide sugars) from the cytosol into the Golgi apparatus. In Arabidopsis, there is an NST subfamily of six members, called URGTs, which transport UDP-rhamnose and UDP-galactose in vitro. URGTs are very similar in protein sequences, and among them, URGT1 and URGT2 are highly conserved in protein sequence and also showed very similar kinetic parameters toward UDP-rhamnose and UDP-galactose in vitro. Despite the similarity in sequence and in vitro function, mutants in urgt1 led to a specific reduction in galactose in rosette leaves. In contrast, mutants in urgt2 showed a decrease in rhamnose content in soluble mucilage from seeds. Given these specific and quite different chemotypes, we wonder whether the differences in gene expression could explain the observed differences between the mutants. Toward that end, we analyzed whether URGT2 could rescue the urgt1 phenotype and vice versa by performing a promoter swapping experiment. We analyzed whether the expression of the URGT2 coding sequence, controlled by the URGT1 promoter, could rescue the urgt1 rosette phenotype. A similar strategy was used to determine whether URGT1 could rescue the urgt2 mucilage phenotype. Expression analysis of the swapped genes, using qRT-PCR, was similar to the native URGT1 and URGT2 genes in wild-type plants. To monitor the protein expression of the swapped genes, both URGTs were tagged with green fluorescent protein (GFP). Confocal microscopy analyses of the swapped lines containing URGT2-GFP showed fluorescence in motile dot-like structures in rosette leaves. Swapped lines containing URGT1-GFP showed fluorescence in dot-like structures in the seed coat. Finally, the expression of URGT2 in urgt1 mutants rescued galactose reduction in rosette leaves. In the same manner, the expression of URGT1 in urgt2 mutants recovered the content of rhamnose in soluble mucilage. Hence, our results showed that their expression in different organs modulates the role in vivo of URGT1 and URGT2. Likely, this is due to their presence in different cellular contexts, where other proteins, acting in partnership, may drive their functions toward different pathways.

New steps in mucilage biosynthesis revealed by analysis of the transcriptome of the UDP-rhamnose/UDP-galactose transporter 2 mutant.

Upon imbibition, epidermal cells of Arabidopsis thaliana seeds release a mucilage formed mostly by pectic polysaccharides. The Arabidopsis mucilage is composed mainly of unbranched rhamnogalacturonan-I (RG-I), with low amounts of cellulose, homogalacturonan, and traces of xylan, xyloglucan, galactoglucomannan, and galactan. The pectin-rich composition of the mucilage and their simple extractability makes this structure a good candidate to study the biosynthesis of pectic polysaccharides and their modification. Here, we characterize the mucilage phenotype of a mutant in the UDP-rhamnose/galactose transporter 2 (URGT2), which exhibits a reduction in RG-I and also shows pleiotropic changes, suggesting the existence of compensation mechanisms triggered by the lack of URGT2. To gain an insight into the possible compensation mechanisms activated in the mutant, we performed a transcriptome analysis of developing seeds using RNA sequencing (RNA-seq). The results showed a significant misregulation of 3149 genes, 37 of them (out of the 75 genes described to date) encoding genes proposed to be involved in mucilage biosynthesis and/or its modification. The changes observed in urgt2 included the up-regulation of UAFT2, a UDP-arabinofuranose transporter, and UUAT3, a paralog of the UDP-uronic acid transporter UUAT1, suggesting that they play a role in mucilage biosynthesis. Mutants in both genes showed changes in mucilage composition and structure, confirming their participation in mucilage biosynthesis. Our results suggest that plants lacking a UDP-rhamnose/galactose transporter undergo important changes in gene expression, probably to compensate modifications in the plant cell wall due to the lack of a gene involved in its biosynthesis.

ESIgen: Electronic Supporting Information Generator for Computational Chemistry Publications.

Electronic supporting information (ESI) occupies a fundamental position in the way scientists report their work. It is a key element in lightening the writing of the core manuscript and makes concise communication easier for the authors. Computational chemistry, as all fields related to structural studies of molecules, tends to generate huge amounts of data that should be inserted in the ESI. ESI reports originating from computational chemistry works generally reach tens of sheets long and include 3D depictions, coordinates, energies, and other characteristics of the structures involved in the molecular process understudy. While most experienced users end up building scripts that dig throughout the output files searching for the relevant data, this is not the case for users without programming experience or time. Here we present an automated ESI generator supported by both web-based and command line interfaces. Focused on quantum mechanics calculations outputs so far, we trust that the community would find this tool useful. Source code is freely available at https://github.com/insilichem/esigen . A web app public demo can be found at http://esi.insilichem.com .