Search Results (407)

Background: Bovine babesiosis, caused by the tick-borne apicomplexan parasite Babesia spp., is an economically significant disease that threatens the cattle industry worldwide. Babesia bovis is the most pathogenic species, leading to high morbidity and mortality in infected animals. One promising approach to vaccination against bovine babesiosis involves the use of multiple protective antigens, offering advantages over traditional live-attenuated vaccines. Tools such as immunobioinformatics and reverse vaccinology have facilitated the identification of novel antigens. Enolase, a “moonlighting” enzyme of the glycolytic pathway with demonstrated vaccine potential in other pathogens, has not yet been studied in B. bovis. Methods: In this study, the enolase gene from two B. bovis isolates was successfully identified and sequenced. The gene, consisting of 1366 base pairs, encodes a predicted protein of 438 amino acids. Its expression in intraerythrocytic parasites was confirmed by RT-PCR. Two peptides containing predicted B-cell epitopes were synthesized and used to immunize rabbits. Hyperimmune sera were then analyzed by ELISA, confocal microscopy, Western blot, and an in vitro neutralization assay. Results: The hyperimmune sera showed high antibody titers, reaching up to 1:256,000. Specific antibodies recognized intraerythrocytic merozoites by confocal microscopy and bound to a ~47 kDa protein in erythrocytic cultures of B. bovis as detected by Western blot. In the neutralization assay, antibodies raised against peptide 1 had no observable effect, whereas those targeting peptide 2 significantly reduced parasitemia by 71.99%. Conclusions: These results suggest that B. bovis enolase contains B-cell epitopes capable of inducing neutralizing antibodies and may play a role in parasite–host interactions. Enolase is therefore a promising candidate for further exploration as a vaccine antigen. Nonetheless, additional experimental studies are needed to fully elucidate its biological function and validate its vaccine potential. Full article

Acetone carboxylase (AC) from Xanthobacter autotrophicus is a 360 KDa α₂β₂γ₂ heterohexamer that catalyzes the ATP-dependent formation of phosphorylated acetone and bicarbonate intermediates that react at Mn(II) metal active sites to form acetoacetate. Structural models of X. autotrophicus AC (XaAC) with and without nucleotides reveal that the binding and phosphorylation of the two substrates occurs ~40 Å from the Mn(II) active sites where acetoacetate is formed. Based on the crystal structures, a significant conformational change was proposed to open and close a tunnel that facilitates the passage of reaction intermediates between the sites for nucleotide binding and phosphorylation of substrates and Mn(II) sites of acetoacetate formation. We have employed electron paramagnetic resonance (EPR), kinetic assays, and hydrogen/deuterium exchange mass spectrometry (HDX-MS) of poised ligand-bound states and site-specific amino acid variants to complete an in-depth analysis of Mn(II) coordination and allosteric communication throughout the catalytic cycle. In contrast with the established paradigms for carboxylation, our analyses of XaAC suggested a carboxylate shift that couples both local and long-range structural transitions. Shifts in the coordination mode of a single carboxylic acid residue (αE89) mediate both catalysis proximal to a Mn(II) center and communication with an ATP active site in a separate subunit of a 180 kDa α₂β₂γ₂ complex at a distance of 40 Å. This work demonstrates the power of combining structural models from X-ray crystallography with solution-phase spectroscopy and biophysical techniques to elucidate functional aspects of a multi-subunit enzyme. Full article

This research aimed to evaluate how different chemical forms of key nutrients, delivered through an advanced foliar product (PRO) and a standard formulation (TRA), influence maize performance when grown on contrasting soil types. Each fertilizer provided a set of macro- and micronutrients, including nitrogen, phosphorus, potassium, boron, copper, iron, manganese, molybdenum, and zinc, along with trace elements such as chromium, iodine, lithium, and selenium. In TRA, Fe and Zn were complexed with EDTA, and trace elements were present in mineral form. In PRO, Fe and Zn were chelated with amino acids, and trace elements were bound to plant extracts. The study examined increasing doses of PRO and their potential toxicity. Both fertilizers improved maize biomass: fresh weight increased by 5–8% and dry weight by 8–14%, depending on the dose. At the lowest dose, yields were similar. However, PRO was more effective in biofortifying maize with iron and zinc on sandy soil, increasing levels by 16% and 7% compared to TRA at the lowest dose and up to 29% at the highest dose. PRO was well tolerated at higher doses. No significant differences were observed between the second and third doses of PRO, suggesting reduced efficacy at the highest dose. Full article

Formononetin is widely used in anti-tumor research, but its poor water solubility leads to low absorption and poor utilization efficiency in vivo, limiting further development. The triphenylphosphine cation was partially attached to the 7-position hydroxyl group of formononetin to specifically target it into the mitochondria of tumor cells to enhance the anti-tumor effect. Detailed structural characterization via ¹H-NMR and ¹³C-NMR analysis confirmed the physical properties and chemical structures of 21 newly synthesized derivatives. The effects of these derivatives on tumor cells were assessed by in vitro and computational methods. MTT results from four tumor cell lines showed that formononetin derivatives containing triphenylphosphine had stronger anti-tumor activity than formononetin and exhibited more cytotoxic effects in cancer cells than in normal cells. In particular, the final product 2c (IC₅₀ = 12.19 ± 1.52 μM) showed more potent anti-tumor activity against A549 cells. It was also superior to formononetin and 5-FU. To identify the potential biological targets, the core-expressed gene SHMT2 in lung cancer mitochondria was screened using network pharmacology technology, and molecular docking analysis confirmed the stable binding of the end products to the amino acid residues of the core genes through the formation of hydrogen bonds and via other interactions. In addition, molecular docking simulations further confirmed that the end product exhibited excellent stability when bound to SHMT2. These results suggest that triphenylphosphine-containing formononetin derivatives are worthy of further exploration in the search for novel drug candidates for the treatment of cancer. Full article

To investigate the effects of water-soluble taste substances (WSTSs) on the physical properties and thermal coagulation properties of reconstituted surimi gels, this study used large yellow croaker muscle (FM) and the WSTS from by-product minced meat (MM) (skin, tail, and head meat (HM)). It was observed that these exogenous additions could effectively improve the surimi gel’s whiteness, gel strength and umami amino acid content. When these were added, the relaxation times of bound water in FM, MM and HM groups were shorter in the 10% exogenous addition treatment, and the surimi particle size (D10, D50, D90, d4, 3, d2, 3) was smaller. This implies a correlation between the WSTS and the moisture preservation capacity of recombinant surimi gels, whereby WSTS facilitates the cross-linking of protein molecules, leading to the formation of a densely interconnected network architecture. This research can provide theoretical guidance for the processing of surimi gel combined fish flavor substances and freshwater surimi, thereby improving the flavor characteristics of freshwater surimi gel. Full article

Mismatched T:G base pairs can arise during de novo replication as well as base excision repair (BER). In particular, the action of the gap-filling polymerase β (Polβ) can generate a T:G pair as well as a nick in the DNA backbone. The processing of a nicked T:G mispair is poorly understood. We are interested in understanding whether the T:G-specific DNA glycosylase MBD4 can recognize and process nicked T:G mismatches. We have discovered that MBD4 binds a nicked T:G-containing DNA, but does not cleave thymine opposite guanine. To gain insight into this, we have determined a crystal structure of human MBD4 bound to a nicked T:G-containing DNA. This structure displayed the full insertion of thymine into the catalytic site and the recognition of thymine based on the catalytic site’s amino acid residues. However, thymine excision did not occur, presumably due to the inactivation of the catalytic D560 carboxylate nucleophile via a polar interaction with the 5′-hydrogen phosphate of the nicked DNA. The nicked complex was greatly stabilized by an ordered water molecule that formed four hydrogen bonds with the nicked DNA and MBD4. Interestingly, the arginine finger R468 did not engage in the phosphate pinching that is commonly observed in T:G mismatch recognition complex structures. Instead, the guanidinium moiety of R468 made bifurcated hydrogen bonding interactions with O6 of guanine, thereby stabilizing the estranged guanine. These observations suggest that R468 may sense and disrupt T:G pairs within the DNA duplex and stabilize the flipped-out thymine. The structure described here would be a close mimic of an intermediate in the base extrusion pathway induced by DNA glycosylase. Full article

Hepatitis B is a serious infectious disease that threatens the health of all mankind. In this study, we isolated and extracted hydroxytyrosol from Lindernia ruellioides with anti-hepatitis B virus (HBV) activity. The structure of hydroxytyrosol was identified by the nuclear magnetic resonance technique. HepG2.2.15 cell models were used to detect the anti-HBV activity and liver protection of hydroxytyrosol in vitro. Hydroxytyrosol can inhibit hepatitis B surface antigen (HBsAg) and hepatitis B e-antigen (HBeAg). The IC₅₀ values of HBsAg and HBeAg were 4.02 mg/L and 5.19 mg/L, respectively. At the highest concentration of hydroxytyrosol, the inhibition rates of supernatant and intracellular HBV DNA were 75.99% and 66.33%, respectively. Hydroxytyrosol was less toxic to normal human hepatocytes. Molecular docking showed that hydroxytyrosol was bound to three amino acid residues of HBV polymerase with a binding energy of −7.0 kcal/mol. This study provided data for the development and utilization of Lindernia ruellioides and the research and development of anti-hepatitis B virus drugs. Full article

PD-L1 (programmed cell death ligand-1) is a protein located on the surface of regulatory cells. It has an immunosuppressive role as it binds specifically to the protein programmed cell death-1 (PD-1), a checkpoint glycoprotein, present on the surface of immune cells such as T and B lymphocytes. Many tumor cells block the immune response by overexpressing PD-L1 on their surface; therefore, targeting PD-L1 represents a powerful strategy that allows tumor localization. To determine the presence of PD-L1 in cells, the use of ad hoc functionalized peptides that bind to PD-L1 can be exploited. One of them is the peptide CLP002 (Trp-His-Arg-Ser-Tyr-Tyr-Thr-Trp-Asn-Leu-Asn-Thr), which, bound to surface-enhanced Raman scattering (SERS) gold nanostructures via a suitable linker, was shown to be highly effective in recognizing MDA-MB-231 breast cancer cells and, importantly, this recognition can be measured by SERS experiments. To characterize, on a molecular scale, the interaction between PD-L1 and peptide functionalized nanostructures, we performed molecular dynamics (MDs) simulations, studying the features of peptide monolayers bound on gold surfaces in the absence and presence of PD-L1. The results obtained allow us to explain why the nature of the linker plays a fundamental role in the binding and why a peptide carrying the same amino acids as CPL002 but with a different sequence (scrambled) is much less active than CLP002. These results open the way to an in silico evaluation of the key parameters that regulate the binding of PD-L1 useful for cancer recognition. Full article

Objective: We developed a targeted integration-based CHO cell platform for simultaneous antibody display and secretion, enabling a streamlined transition from antibody library screening to production without requiring the re-cloning of antibody genes. Methods: The platform consists of a CHO master cell line with a single-copy landing pad, a helper vector expressing FLPe recombinase, and bi-functional targeting vectors. Recombinase-mediated cassette exchange was utilized to integrate targeting vectors into the landing pad. Bi-functional vectors were designed by incorporating a minimal furin cleavage sequence (mFCS), RRKR, and various 2A peptides between the heavy chain (HC) and a membrane anchor. Results: Incomplete cleavage at the mFCS and 2A sites facilitated the expression of both membrane-bound and secreted antibodies, while mutations in the 2A peptide produced a range of display-to-secretion ratios. However, a fraction of secreted antibodies retained 2A residues attached to the HC polypeptides. Further analysis demonstrated that modifying the first five amino acids of the 2A peptide significantly influenced furin cleavage efficiency, resulting in different display-to-secretion ratios for targeting vectors containing mFCS-2A variant combinations. To overcome this, we designed nine-amino-acid FCS variants that, when placed between the HC and membrane anchor, provided a range of display-to-secretion ratios and eliminated the issue of attached 2A residues in the secreted antibodies. Vectors with lower display levels proved more effective at distinguishing cells expressing high-affinity antibodies with closely matched binding affinities. The platform also demonstrated high sensitivity in isolating high-affinity antibody-expressing cells and supported robust antibody production. Conclusion: This targeted integration-based CHO platform enables efficient, in-format screening and production of antibodies with tunable display-to-secretion profiles. It provides a powerful and scalable tool for accelerating the development of functional, manufacturable therapeutic antibodies. Full article

There are about 5000 species of Passeriformes birds, which are half of the extant ones. Their class I MHC molecules are found to be different from all other studied vertebrates, including other bird species; i.e., amino acid residues 10 and 96 are not the seven canonic residues extant in all other vertebrate molecules. Thus, the canonic residues in MHC class I vertebrate molecules are reduced to five. These differences have physical effects in MHC (Major Histocompatibility Complex) class I alpha chain interaction with beta-2-microglobulin but have yet unknown functional effects. Also, introns show specific Passeriformes distinction both in size and invariance. The studies reviewed in this paper on MHC structure have been done in wild birds that cover most of the world’s passerine habitats. In this context, we are going to expose the most commonly occurring bird diseases with the caveat that MHC and disease linkage pathogenesis is not resolved. In addition, this field is poorly studied in birds; however, common bird diseases like malaria and Marek’s disease are linked to MHC. On the other hand, the main established function of MHC molecules is presenting microbial and other antigens to T cells in order to start immune responses, and they also may modulate the immune system through NK receptors and other receptors (non-classical class I MHC molecules). Also, structural and polymorphic differences between classical class I molecules and non-classical class I molecules are at present not clear, and their definition is blurred. These passerine exceptional MHC class I molecules may influence linkage to diseases, transplantation, and other MHC presentation and self-protection functions. Further studies in more Passeriformes species are ongoing and needed. Full article

Enterotoxigenic Bacteroides fragilis (ETBF) is an intestinal bacterium that secretes the metalloprotease Bacteroides fragilis toxin (BFT), which induces E-cadherin cleavage and interleukin-8 secretion in human intestinal epithelial cell lines. ETBF-induced E-cadherin cleavage is proposed to be the underlying reason for the promotion of colitis in ETBF-infected mice. However, a BFT-responsive murine cell line has not yet been reported. In the current study, we report that the mouse colonic epithelial cell line CMT93 undergoes E-cadherin ectodomain cleavage, cell rounding, and proliferation in response to BFT treatment. The amino acid sequence of the putative cleavage site of E-cadherin is identical in both BFT-responsive (CMT93) and BFT-nonresponsive (MSIE, CT26, YAMC, and B16) cell lines, suggesting that the E-cadherin amino acid sequence is not responsible for this observation. After E-cadherin ectodomain cleavage, the membrane-bound intracellular E-cadherin domain underwent cleavage by γ-secretase and was subsequently degraded by the proteasome. Moreover, BFT induced the secretion of two chemokines (LIX and KC) and the formation of soluble TNFR1 in the CMT93 cell line. The identification of a BFT-responsive murine cell line may be used to elucidate the mechanism of ETBF pathogenesis in ETBF murine infection models. Full article

Danshen, a well-known traditional Chinese medicine (TCM), has gained increasing attention for its protective effects on nonalcoholic fatty liver disease (NAFLD). However, the molecular mechanisms underlying these effects remain to be elucidated. Niemann-Pick C1-like 1 (NPC1L1), a key transporter mediating intestinal cholesterol absorption, has emerged as a critical target for NAFLD treatment. This study aimed to screen for NPC1L1 inhibitors from Danshen and investigate their therapeutic effects on NAFLD. We established a high-throughput screening platform using stable Caco2 cell lines expressing human NPC1L1 (hL1-Caco2) and discovered that tanshinones (Tans), the liposoluble components of Danshen, inhibited NPC1L1-mediated cholesterol absorption in hL1-Caco2 cells. Additionally, Tans treatment reduced hepatic steatosis in high-fat diet (HFD)-fed mice. To identify the active compounds in Tans, activity-oriented separation was performed by integrating the high-throughput screening platform and two-dimensional chromatographic techniques. Ultimately, cryptotanshinone (CTS) was identified as a novel NPC1L1 inhibitor and significantly decreased hepatic steatosis in HFD-fed mice. Molecular docking and dynamics simulation showed that CTS stably bound with NPC1L1, where TRP383 acted as the key amino acid. Taken together, this study demonstrates, for the first time, that CTS, a liposoluble compound from Danshen, is a novel NPC1L1 inhibitor. Our findings suggest that the inhibitory effect of CTS against NPC1L1-mediated intestinal cholesterol absorption may be a potential mechanism, contributing to its alleviation of NAFLD in mice. Full article

One ton of potatoes processed to starch yields 5 to 12 m³ of potato fruit juice (PFJ), containing 30–41 wt% per dry matter protein with a high nutritional value that is comparable to eggs and has all essential amino acids. However, high levels of phenolics reduce potato protein concentrate (PPC) quality and taste. This study deployed a sustainable method evaluating novel adsorption resins to bind phenolics in PFJ and improve the PPC. Resins exhibited aqueous phenolic binding capacities ranging from 317 ± 0.5 mg to 606 ± 0.9 mg of Gallic Acid bound per mL of resin. The best performing resin, Strong Anion Exchanger (SAX) 002, significantly reduced PFJ total phenolic content (TPC) from 295 ± 0.6 μg/mL to 84 ± 0.1 μg/mL (Gallic Acid Equivalent (GAE)). Weak Anion Exchanger (WAX) 007 and 008 also decreased TPC to 155 ± 0.2 μg/mL GAE and 154 ± 0.3 μg/mL GAE, respectively. However, the most effective phenolic-binding resin resulted in a lower PPC yield versus control. In contrast, WAX 003 showed moderate phenolic removal but resulted in a higher yield (60 ± 0.69% to 90.1 ± 0.1% of control), demonstrating a trade-off between phenolic reduction and PPC recovery. SAX resins are superior in lowering PFJ and PPC phenolic content through adsorption. The results show the possibilities of using specialized resins to improve PPC quality for human consumption. Full article

Zein was made flexible through acid-driven deamidation. This increased flexibility was confirmed by the higher release of water-soluble peptides during trypsin hydrolysis. Self-assembled flexible zein nanoparticles (FZNPs) were prepared using the anti-solvent precipitation method. To test the sensitivity of FZNPs to complex environment, ionic solutions (CaCl₂ and NaCl) at various concentrations were prepared. The morphology and particle size of FZNPs differed significantly from those of control zein nanoparticles (NZNPs). As the ionic concentration increased from 0 to 15 mmol/L, FZNPs showed higher electrical conductivity and adsorption capacity than NZNPs. This suggests that FZNPs are highly sensitive to complex environment. X-Ray Photoelectron Spectrum (XPS) results revealed that both FZNPs and NZNPs bound more Na⁺ than Ca²⁺. The enhanced sensitivity of FZNPs to complex environments may be due to their greater tendency for structural changes. These conformational changes are likely caused by the altered amino acids in flexible zein, which result from deamidation. This study offers a practical approach to designing novel nanoparticles as functional materials for delivering bioactive compounds. Full article

Ghrelin is a 28 amino acid peptide hormone that impacts a wide range of biological processes, including appetite regulation, glucose metabolism, growth hormone regulation, and cognitive function. To bind and activate its cognate receptor, ghrelin must be acylated on a serine residue in a post-translational modification performed by ghrelin O-acyltransferase (GOAT). GOAT is a membrane-bound O-acyltransferase (MBOAT) responsible for the catalysis of the addition of an octanoyl fatty acid to the third serine of desacyl ghrelin. Beyond its canonical role for ghrelin maturation in endocrine cells within the stomach, GOAT was recently reported to be overexpressed in prostate cancer (PCa) cells and detected at increased levels in the serum and urine of PCa patients. This suggests GOAT can serve as a potential route for the detection and therapeutic targeting of PCa and other diseases that exhibit GOAT overexpression. Building upon a ghrelin mimetic peptide with nanomolar affinity for GOAT, we developed an antibody-conjugate-inspired system for customizable ligand-conjugate (LC) synthesis allowing for the attachment of a wide range of cargoes. The developed synthetic scheme allows for the easy synthesis of the desired LCs and demonstrates that our ligand system tolerates an extensive palette of cargoes while maintaining nanomolar affinity against GOAT. Full article