Bdellovibrio bacteriovorus is an endobiotic bacterial predator that encodes multiple enzymes related to known peptidoglycan (PG) modifiers, which are necessary for predation to occur. Additionally, a ...plethora of cryptic proteins are expressed and upregulated during predation. It has been shown that L,D-transpeptidases (LDTs) are required for bdelloplast formation and stabilisation. These LDTs cluster in six groups in B. bacteriovorus HD100, nevertheless, no further LDT information has been previously described. Here we have determined and analysed the structures of LDTs Bd0566, Bd1075, Bd3334 and Bd3741, showing that even though they share a structurally conserved catalytic domain, they have acquired accessory domains and motifs characteristic to each LDT group. Moreover, we have integrated these novel structures with the previously solved structures of Bd0553, Bd0886 and Bd1402, generating a panel of seven LDTs representing the six groups of B. bacteriovorus HD100, allowing us to propose possible roles and the structural determinants defining the transferase/crosslinking or hydrolytic activities of each group. Further, we report the structure of two predatory NlpC/P60 amidohydrolases/peptidases, Bd0601 and Bd1177. We have determined that Bd0601 is a DUF1460 amidohydrolase, wherein the PG stem peptide binding groove is blocked by a tyrosine residue, suggesting the need of a conformational rearrangement for substrate binding. On the other hand, we have determined that Bd1177 is a bilobular NlpC/P60, wherein the active site is located in the interface between the catalytic N-terminal domain and a novel C-terminal regulatory domain, suggesting that Bd1177 fluctuates to an open conformation upon substrate binding. Finally, we have determined the crystallographic structure of the cryptic secreted protein Bd0675, depicting a novel fold. The solved structure depicts a prominent central acidic and aromatic groove delimited by a conserved disulphide-stabilised loop, suggesting that this protein has ligand binding functions. Based on the solved structure we have tested different candidate ligands; however further experiments are required to propose a function for Bd0675. In addition, due to its novelty, Bd0675 was used as target for multiple structure predicting algorithms in CASP14.
The Sec61 translocon allows the translocation of secretory preproteins from the cytosol to the endoplasmic reticulum lumen during polypeptide biosynthesis. These proteins possess an N‐terminal signal ...peptide (SP) which docks at the translocon. SP mutations can abolish translocation and cause diseases, suggesting an essential role for this SP/Sec61 interaction. However, a detailed biophysical characterization of this binding is still missing. Here, optical tweezers force spectroscopy was used to characterize the kinetic parameters of the dissociation process between Sec61 and the SP of prepro‐alpha‐factor. The unbinding parameters including off‐rate constant and distance to the transition state were obtained by fitting rupture force data to Dudko–Hummer–Szabo models. Interestingly, the translocation inhibitor mycolactone increases the off‐rate and accelerates the SP/Sec61 dissociation, while also weakening the interaction. Whereas the translocation deficient mutant containing a single point mutation in the SP abolished the specificity of the SP/Sec61 binding, resulting in an unstable interaction. In conclusion, we characterize quantitatively the dissociation process between the signal peptide and the translocon, and how the unbinding parameters are modified by a translocation inhibitor.
The biological and functional significance of selected Critical Assessment of Techniques for Protein Structure Prediction 14 (CASP14) targets are described by the authors of the structures. The ...authors highlight the most relevant features of the target proteins and discuss how well these features were reproduced in the respective submitted predictions. The overall ability to predict three‐dimensional structures of proteins has improved remarkably in CASP14, and many difficult targets were modeled with impressive accuracy. For the first time in the history of CASP, the experimentalists not only highlighted that computational models can accurately reproduce the most critical structural features observed in their targets, but also envisaged that models could serve as a guidance for further studies of biologically‐relevant properties of proteins.
Tomato (Solanum lycopersicum L.) is one of the most important crops in Mexico due to its economic and nutritional value. Among the main diseases in tomato production is Fusarium wilt, which can cause ...60% production losses (Ascencio et al, 2008). Mixed infections of Fusarium species or other fungi genera, would increase disease severity. During April to May of 2021, tomato plants with more than 60 days old, were collected from the main production areas of Aguascalientes (22°03'46.5"N 102°05'17.4"W and 22°04'53.64"N 101°58'55.81"W) and Zacatecas (23°05'59.2"N 102°41'07.3"W and 22°16'52.1"N 102°00'11.8"W) Mexico states. Plants showed main root rot, vascular bundles necrosis with corky appearance, stem crown rot, and ascending yellowing. The main root and stem crown were cut in 0.25 cm2 pieces and disinfested in 2% NaClO for one minute, rinsed with distilled water two times, placed on acidified potato dextrose agar (PDA) medium, and incubated at 25 ± 2°C for 7 days. Characteristic Fusarium growths were purified by hyphal tip on PDA, subsequently pure strains were obtained by single-spore isolation method. Several fungi colonies were obtained, but we focused on the colonies that showed abundant aerial mycelium of white color and irregular growth, which turned yellowish to golden and brown color as it ages. Carnation leaf agar (CLA) medium were used for conidia and sporodochium development. Chains of terminal, intercalary and agglomerated chlamydospores with thick, rough brown walls of 18.9 (7.46) µm in diameter (n=120) were observed in the mycelium. Macroconidia with 5 to 7 septa were 30 to 75 (28.32) µm in long and 1.2 to 4.8 (3.2) µm in wide (n=72). Basal cell developed in foot-shape, apical cell was elongated and slightly curved, and some macroconidia had swollen midd-cell. Sporodochium was orange to brown in color and microconidia were absent (Figure 1). Two representative strains from each state, LCA-3.1 and EMA-1 from Aguascalientes and ECZ-4 and LRZ-6 from Zacatecas, were selected for DNA amplification of ITS, TEF-1α and RPB2 regions, with universal primers ITS1/ITS4, EF1/EF2 and 2-5F2/7cR (White et al.1990; O'Donnell et al. 1998, 2013). PCR products were sequenced by Psomagen, Inc. (USA). The sequences obtained showed 100% of similarity among themselves and within species of the Fusarium incarnatum-equiseti species complex (FIESC) with nucleotide NCBI accessions NR_121457 (Type material) for ITS and MW362069 for TEF-1α; and 99.28% with MN170399 for RPB2 in FUSARIOID-ID database. According to morphological (Leslie and Summerell, 2006) and molecular characteristics, isolates were identified as Fusarium equiseti (FIESC 14). The LCA-3.1 sequences were selected to be deposited in GenBank with accession numbers OM812801 (ITS), OM937108 (TEF-1α) and ON653596 (RPB2). Pathogenicity tests were performed twice, under greenhouse conditions in tomato seedlings of cv. Rio Grande. Five tomato seedlings were inoculated by root immersion method (Lopez et al, 2018) in a 1x106 spores/mL solution for 8 min, and transplanted to 1L pots with sterile peat. Five controls plants were immersed in sterile water. At 14 days after inoculation, a general plant decline and slower growth compared to the control plants were observed. Subsequently, plants showed root rot, vascular necrosis, and a brown ring in stem crown. Controls were symptomless. The fungi were re-isolated from symptomatic plants and were morphologically similar to the inoculated strains. Patel et al. (2017) described the pathogenic and toxic effects of F. equiseti on tomato, causing low seed germination, and low root and shoot growth. This is the first report of F. equiseti causing root and stem rot in tomato plants in Mexico.
We report on the formation of two novel multifunctional isomorphous (4,4) square-grid 2D coordination polymers based on 1H-indazole-5-carboxylic acid. To the best of our knowledge, these complexes ...are the first examples of 2D-coordination polymers constructed with this novel ligand. We have analysed in detail the structural, magnetic and anti-parasitic properties of the resulting materials. In addition, the capability of inhibiting nitric oxide production from macrophage cells has been measured and was used as an indirect measure of the anti-inflammatory response. Finally, the photocatalytic activity was measured with a model pollutant, i.e. vanillic acid (phenolic compound), with the aim of further increasing the functionalities and applicability of the compounds.
We report on the formation of two isomorphous (4,4) square-grid 2D coordination polymers based on 1H-indazole-5-carboxylic acid. These materials show interesting magnetic, anti-parasitic and anti-inflammatory properties. Display omitted
•New 2D coordination polymers based on 1H-indazole-5-carboxylic acid are reported.•Magnetic studies have been performed.•Compounds show interesting anti-parasitic properties.•Anti-inflammatory activities have been analysed.•Cytotoxicity in macrophages has been measured.
Summary Background Erlotinib has been shown to improve progression-free survival compared with chemotherapy when given as first-line treatment for Asian patients with non-small-cell lung cancer ...(NSCLC) with activating EGFR mutations. We aimed to assess the safety and efficacy of erlotinib compared with standard chemotherapy for first-line treatment of European patients with advanced EGFR-mutation positive NSCLC. Methods We undertook the open-label, randomised phase 3 EURTAC trial at 42 hospitals in France, Italy, and Spain. Eligible participants were adults (>18 years) with NSCLC and EGFR mutations (exon 19 deletion or L858R mutation in exon 21) with no history of chemotherapy for metastatic disease (neoadjuvant or adjuvant chemotherapy ending ≥6 months before study entry was allowed). We randomly allocated participants (1:1) according to a computer-generated allocation schedule to receive oral erlotinib 150 mg per day or 3 week cycles of standard intravenous chemotherapy of cisplatin 75 mg/m2 on day 1 plus docetaxel (75 mg/m2 on day 1) or gemcitabine (1250 mg/m2 on days 1 and 8). Carboplatin (AUC 6 with docetaxel 75 mg/m2 or AUC 5 with gemcitabine 1000 mg/m2 ) was allowed in patients unable to have cisplatin. Patients were stratified by EGFR mutation type and Eastern Cooperative Oncology Group performance status (0 vs 1 vs 2). The primary endpoint was progression-free survival (PFS) in the intention-to-treat population. We assessed safety in all patients who received study drug (≥1 dose). This study is registered with ClinicalTrials.gov , number NCT00446225. Findings Between Feb 15, 2007, and Jan 4, 2011, 174 patients with EGFR mutations were enrolled. One patient received treatment before randomisation and was thus withdrawn from the study; of the remaining patients, 86 were randomly assigned to receive erlotinib and 87 to receive standard chemotherapy. The preplanned interim analysis showed that the study met its primary endpoint; enrolment was halted, and full evaluation of the results was recommended. At data cutoff (Jan 26, 2011), median PFS was 9·7 months (95% CI 8·4-12·3) in the erlotinib group, compared with 5·2 months (4·5–5·8) in the standard chemotherapy group (hazard ratio 0·37, 95% CI 0·25–0·54; p<0·0001). Main grade 3 or 4 toxicities were rash (11 13% of 84 patients given erlotinib vs none of 82 patients in the chemotherapy group), neutropenia (none vs 18 22%), anaemia (one 1% vs three 4%), and increased amino-transferase concentrations (two 2% vs 0). Five (6%) patients on erlotinib had treatment-related severe adverse events compared with 16 patients (20%) on chemotherapy. One patient in the erlotinib group and two in the standard chemotherapy group died from treatment-related causes. Interpretation Our findings strengthen the rationale for routine baseline tissue-based assessment of EGFR mutations in patients with NSCLC and for treatment of mutation-positive patients with EGFR tyrosine-kinase inhibitors. Funding Spanish Lung Cancer Group, Roche Farma, Hoffmann-La Roche, and Red Temática de Investigacion Cooperativa en Cancer.
We report the formation of five novel multifunctional coordination polymers based on 1H-indazole-4-carboxylic acid (HL). To the best of our knowledge, these complexes are the first examples of ...coordination compounds constructed with this interesting ligand. These materials were synthesized by solvothermal routes, possess different 2D-structures and show interesting magnetic properties due to the copper compound showing an unusual spin-canted effect while the anisotropic cobalt material behaves as a field-induced single molecule magnet. MTT assays performed on human embryonic kidney (HEK293) and mouse skin melanoma (B16-F10) cell lines indicated that the Cd-based compound was the only one exhibiting dose-dependent toxicity on B16-F10 cells, most likely due to the release of toxic Cd(ii). Cadmium and zinc polymers exhibit interesting luminescence properties. The fact that zinc polymers did not exhibit inherent toxicity against both cancer and non-cancerous cells make this new family an excellent candidate for further investigation in the field of luminescent materials with biomedical applications.
Two new coordination polymers (CPs) based on Zn(II) and Cd(II) and 1H-indazole-6-carboxylic acid (H2L) of general formulae Zn(L)(H2O)n (1) and Cd2(HL)4n (2) have been synthesized and fully ...characterized by elemental analyses, Fourier transformed infrared spectroscopy and single crystal X-ray diffraction. The results indicate that compound 1 possesses double chains in its structure whereas 2 exhibits a 3D network. The intermolecular interactions, including hydrogen bonds, C–H···π and π···π stacking interactions, stabilize both crystal structures. Photoluminescence (PL) properties have shown that compounds 1 and 2 present similar emission spectra compared to the free-ligand. The emission spectra are also studied from the theoretical point of view by means of time-dependent density-functional theory (TD-DFT) calculations to confirm that ligand-centred π-π* electronic transitions govern emission of compound 1 and 2. Finally, the PL properties are also studied in aqueous solution to explore the stability and emission capacity of the compounds.
In order to facilitate the preoperative prediction of complicated appendicitis, we propose a complementary approach by selecting an endpoint defined by the intraoperative finding of peritoneal ...soiling (PS).
Over a 6-month period, 38 centers (5% of all public hospitals) attending emergency general surgery patients on a 24-h, 7-days a week basis, enrolled consecutive adult patients requiring appendectomy. Patients were stratified according to the absence or the finding of PS during the surgical procedure.
A total of 2645 patients were included; median age (IQR) was 35 (22–51) years, 44.3% were female. The laparoscopic approach was used in 70.8% of appendectomies. In a third of patients (31.7%), there was PS with pus around the appendix, or bowel contents, free pus, or blood in the peritoneal cavity. To develop the prediction model, 1764 patients were randomly selected for the derivation cohort and the remaining 881 patients were assigned to the validation cohort. On multivariable logistic regression analysis of all patients, two clinical variables (age, and pulse) and three laboratory variables (serum urea, serum sodium, and white blood cell count) were individually associated (P < .05) with a greater probability of having PS (Hosmer-Lemeshow chi, 1.63; P = .99; C-statistic, 0.7). Based on the multivariable regression model, both static and dynamic nomograms were developed for the prediction of PS in patients with acute appendicitis.
The entry of simple clinical and laboratory variables in the dynamic nomogram may be useful in guiding the initial management of patients with acute appendicitis in resource-limited settings.
•Mortality from complicated appendicitis still high in underserved areas of the world.•The study offers a dynamic nomogram to predict peritoneal soiling in appendicitis.•The nomogram employs simple, readily available clinical and laboratory data.•Age, pulse rate, serum urea, serum sodium, and white cell count are required.•Prediction of complicated appendicitis made feasible in resource-limited settings.
Understanding the determinants of vaccine hesitancy is paramount to reinstate confidence in immunizations. The objective of this investigation was to explore the characteristics of the vaccination ...decision-making process that may result in the refusal of childhood immunization in Peru, during February-June 2020. A descriptive, cross-sectional study involving telephone interviews was executed in Peru. The Parents Attitudes about Childhood Vaccines (PACV) survey was used. A demographic analysis was done, followed by an unadjusted exploratory subgroup analysis. Out of 552 subjects, 9.8% were considered vaccine hesitant, 70.3% had purposively delayed vaccination, 88.4% thought fewer vaccines were better and 52.2% were concerned about vaccine safety. The level of hesitancy was inversely proportional to the level of education and the number of children at home. Mothers and subjects aged ≤29 years showed a greater level of vaccine hesitancy. This population displays a vaccine-hesitant conduct. Vaccine safety and the number of vaccines to administer are important determining factors. This behavior could be influenced by variables such as level of education, number of children at home, parental relationship, and age. These results help understand local vaccination behaviors. More studies are encouraged to confirm and validate these findings.
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