Current Pharmaceutical Biotechnology - Volume 24, Issue 5, 2023

The domoic acid (DA) produced by certain species of the marine pennate diatom genus Pseudo-nitzschia is highly neurotoxic and can induce nerve excitability and neurotoxicity by binding with ionotropic glutamate receptors, causing amnesic shellfish poisoning in humans who consume seafood contaminated with DA. In recent years, poisoning of humans caused by DA has occurred around the world, which has attracted increasing attention, and studies on DA production by Pseudo-nitzschia have become the hotpot. This article reviews the progress in the biosynthesis of DA by the typical diatom Pseudo-nitzschia, in which the metabolic pathway of the biosynthesis of DA and its precursors, i.e., geranyl pyrophosphate and L-glutamate, and the various environmental factors affecting DA production including temperature, light intensity, nutrients, trace metals, and alien bacteria are discussed. The detection methods of DA (including bioassays, enzyme linked immunosorbent assays, high performance liquid chromatography, capillary electrophoresis and biosensors), as well as the morphology and toxigenicity of Pseudo-nitzschia are also presented.

Hepatitis, an inflammation of the liver parenchyma, is a viral disease. Addressing the challenges of hepatitis is very important. Therefore, using nanoparticles (NPs) in solving the problems of hepatitis diagnosis and treatment can be considered a promising approach. To the best of our knowledge, there are few studies to review the most widely used and effective NPs in the field of hepatitis. A literature review was performed on the publications available on the subject matter from 2011 to 2021. The keywords in different combinations such as “hepatitis,” “nanobiosensor,” “nanoparticles,” “drug delivery,” “vaccination,” “HBV,” and “HCV” were searched in databases of PubMed and Scopus. The collected data were then analyzed. Our review study for introducing the widely used metallic, polymeric and carbon-based NPs with more promising effects in the field of hepatitis virus infection shows that the most effective metallic NPs were gold nanoparticles for designing detection sensors. Also, among polymeric NPs, chitosan NPs seem to be the best nanocarriers in drug delivery and vaccination for hepatitis and among carbon-based NPs, carbon dots had more promising effects for biosensing of hepatitis. According to the results, it is suggested that more studies could be conducted on these NPs for further studies on hepatitis as well as other viral infectious diseases.

Background: Non-alcoholic fatty liver disease (NAFLD) is now considered the most common chronic liver disease worldwide. NAFLD is related to changes in lipid metabolism and is characterized by the increase or accumulation of fat in hepatocytes that may progress to nonalcoholic steatohepatitis (NASH), which leads to the appearance of inflammatory processes. Treatment consists of changes in diet, physical activity, and weight control; however, these disorders represent a health problem and require the development of novel alternatives to treatment and prevention. NAFLD/NASH are strongly associated with other disorders, such as metabolic syndrome (MetS); in fact, NAFLD is considered the hepatic manifestation of MetS. These disorders are related to other components of MetS, including dyslipidemia, which is characterized by an imbalance in blood cholesterol and triglyceride levels. Prebiotics and probiotics benefit from treating and preventing several ailments, including liver diseases. Specifically, in dyslipidemia, NAFLD, and NASH, probiotics play a fundamental role in conducting the biotransformation of primary bile acids into secondary bile acids, which generally have important activity as immunomodulators and metabolism regulators. The mechanisms of action of pre and probiotics involve the activity of bile acid receptors, such as FXR and TGR-5, and the events resulting from their activation. Therefore, prebiotics and probiotics may be reasonable options to prevent and treat metabolic- related liver diseases.

Helicobacter pylori infection is a common health problem, which can cause gastric and extragastric diseases. Accurate detection of H. pylori is critical for appropriate patient management and bacterial eradication. In this regard, there are several methods for the diagnosis of H. pylori infection, which are classically divided into two major groups of invasive and non-invasive methods. Invasive methods, such as endoscopy, histology, and relative culture are less preferred due to their operational difficulties. By contrast, non-invasive methods, such as urea breath test, (UBT) are clinically preferred. Moreover, molecular methods, including polymerase chain reaction (PCR)-based methods, next-generation sequencing (NGS), and DNA microarray, have shown good sensitivity and specificity, and are considered helpful in H. pylori diagnosis. These methods have also increasingly concentrated on the detection of bacterial antibiotic resistance patterns. Besides, point of care (POC) devices play an important role in H. pylori diagnosis, mainly by shortening the time to the result and by making the test available at the bedside or at remote care centres. Biosensors, including aptasensors, have shown to be more appropriate tools because of their low limit of detection, high selectivity, fast response, and ease of handling. Finally, new emerging techniques, like MALDI-TOF MS, have been considered as fast methods with high degree of accuracy and sensitivity to identify and differentiate new species of H. pylori. The current article reviews the most recent developments in invasive, noninvasive, and molecular approaches for the diagnosis of H. pylori infections. Moreover, the application of emerging techniques, including MALDI-TOF MS and recently developed POCs, and biomarker-based methods, is discussed.

Plant lectins are carbohydrate-binding proteins that are ubiquitously found in almost all plant species and have different structures and functions depending on the sources. Purifying lectins from their plant sources and determining their sugar specificity become an important goal for evaluating their potential biomedical applications. Here, we report the affinity purification of a Dgalactose specific lectin from the seeds of Meizotropis buteiformis Voigt., and its physicochemical parameters, and LC-MS/MS (tandem mass spectrometry) analysis. Isolation and purification of this lectin were performed by simple successive steps of lectin extraction, ammonium sulphate fractionation, and affinity chromatography using lactose-linked Sepharose-4B chromatography column. The affinity-purified lectin has a native molecular weight of 75 kDa and is found to be a heterodimer (molecular weight of 36 and 38 kDa). The LC-MS/MS results suggested that the purified lectin had not been reported earlier. Aim: The main aim of the present study is to find out the novelty and characteristics of a lectin purified from the plant Meizotropis buteiformis. Background: Lectins are proteins that possess the ability to specifically bind glycans of glycoconjugates. Plants are considered rich sources of lectins and the determination of sugar specificity of a purified plant lectin is an important aspect in order to evaluate its potential area of application. In the present study, a novel D-Galactose specific lectin is purified from Meizotropis buteiformis through affinity chromatography and examined for its various physical and biochemical characteristics. Objective: The objective of the present study is to purify a novel lectin up to its homogeneity from the seeds of Meizotropis buteiformis and characterization of its various physical and biochemical properties. Methods: The lectin was purified by simple successive steps of lectin extraction, ammonium sulphate fractionation, and affinity chromatography. Activity of the purified lectin was determined by hemagglutination assay. Some physicochemical parameters of the purified protein were also determined along with identification of protein by LC-MS/MS and the spectra analysis using Mascot sequence matching software (Matrix Science) with the NCBI database. Results: From the current investigation, it was found that the purified lectin has a native molecular weight of 75 kDa. Among the various sugars and sugar derivatives tested, lactose and D-galactose were found to be potent inhibitors of its activity. Its optimum pH range was found to be from 6.5 to 7.5 and also it exhibited full activity at a temperature from 0ºC to 50ºC. The purified lectin does not show any effects on its activities for metal ions tested. The protein view report of the LC-MS/MS result analysis showed a 50% sequence similarity with that of the lectin beta-chain of the Butea monosperma. Conclusion: In the present study, a novel D-Galactose specific lectin is purified from Meizotropis buteiformis by affinity chromatography using Sepharose 4B. The purified lectin is found to be heterodimeric and metal ion independent. The LC-MS/MS results suggested that the purified lectin has not been reported earlier.

Background: Dysregulated Yes-associated protein 1 (YAP1) is closely associated with cancer progression and chemo-resistance. We aim to explore the role of YAP1/Hippo pathway in regulating doxorubicin (ADM)-resistance in acute myeloid leukemia (AML). Methods: In this study, we established two ADM-resistant cell lines (THP-1/ADM and K562/ ADM). Then, cell viability and apoptosis were detected by MTT assay and FCM assay, respectively. Real-time PCR was performed to examine the expression of genes in the AML/ADM cells and the clinic BM samples. The levels of all related proteins were examined by Western blot. Results: We found that the YAP1 and its downstream target genes, including EGFR, SOX2, and OCT4, were associated with ADM resistance, evidenced by the increased expression in ADMresistant AML/ADM cells and clinical BM specimens. Additionally, YAP1 ablation enhanced the promoting effects of ADM treatment on cell death in AML/ADM cells. Conversely, YAP1 increased ADM-a resistance in the original ADM-sensitive AML cells. These results may provide important new insights into understanding the role of YAP1 in regulating AML resistance by affecting CSCs characteristics. Conclusion: In summary, we evidenced that the dysregulated YAP1/Hippo pathway influenced ADM resistance in AML. YAP1 might be a novel biomarker for the treatment of drug resistance in AML.

Background: Glioblastoma multiforme (GBM) is a heterogeneous and highly vascularized brain tumor that avoids apoptosis due to P-glycoprotein (P-gp) mediated multidrug resistance. Therefore, the development of new therapeutic strategies that induce apoptosis and inhibit proliferation is urgently warranted. Objectives: We examined the efficacy of the combination of baicalin (BAI) and knockdown of miR-148a gene in human glioblastoma T98G and U87MG cell lines. Methods: T98G and U87MG cells were transfected with miR148a siRNA. The influence of miR- 148a siRNA in combination with BAI on T98G and U87MG cell viability, proliferation, apoptosis, and autophagy was evaluated as well. Alterations in the mRNA expression of autophagy-related genes were analyzed using RT-qPCR. Results: The transfection of T98G and U87MG cells with miR148a specific siRNA and exposition on baicalin led to a significant reduction in cell viability and proliferation, the accumulation of sub G1-phase cells and a reduced population of cells in the S and G2/M phases (only in U87MG cell line), increased population of cells in the S phase in T98G cell line and apoptosis or necrosis induction and induction of autophagy for both cell lines. Conclusion: The siRNA-induced miR-148a mRNA knockdown in combination with baicalin may offer a novel therapeutic strategy to more effectively control the growth of human GBM cells. Thus, knockdown of this gene in combination with baicalin inhibits proliferation (cell cycle arrest in the S phase in T98G but not in U87MG cells), induces apoptosis, and regulates autophagy in T98G and U87MG cells. However, further studies are urgently needed to confirm a positive phenomenon for the treatment of GBM.

Introduction: The marine ecosystem contains many microbial species that produce unique, biologically active secondary metabolites with complex chemical structures. We aimed to isolate and identify bioactive compounds with antimicrobial properties produced by a facultative anaerobic strain of Bacillus subtilis (AU-RM-1), isolated from marine sediment. Methodology: We optimized the AU-RM-1 growth conditions, analyzed its growth kinetics and its phenotypic and genotypic characteristics. Extracts of the isolate were studied for antimicrobial activity against three clinically important microorganisms and the structure of the active compound was identified by spectroscopy. Results: Antimicrobial activity of the AU-RM-1 DMSO extract was evaluated by disc diffusion assay and by serial dilution. The AU-RM-1 DMSO extract showed antimicrobial activity against Candida albicans, Escherichia coli, and Klebsiella pneumoniae. The bioactive fraction of the AURM- 1 DMSO extract was separated by TLC-bioautography at Rf = 0.49. We then used scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to study the morphological changes in the bacterial cells treated with the isolated compound. It was observed that cells seemed to shrink, and the cell walls appeared to be damaged. A bioactive compound was identified, and its structure was examined by spectroscopic analysis: a LC-MS molecular ion peak (ESI) m/z (% of relative abundance) was calculated for C19H22O3: 298.38, and found to be C19H22O3⁺¹: 299.51 [M+1]. The chemical structure of the compound (2-(2-{8-methoxy-5aH,6H,7H,8H,9H, 9aH-naphtho[2,1-b]furan-7-yl}ethyl)furan) was determined using ¹HNMR and ¹³CNMR, and its purity was confirmed by HPLC. Fifteen known and previously reported compounds were also identified, in addition to the novel compound; these were lipopeptides, antibiotics and chemical moieties. Conclusion: The facultative anaerobic marine organism Bacillus subtilis (AU-RM-1) produces a novel bioactive secondary metabolite with antimicrobial and antifungal activity.

Background: Gastric cancer (GC) is the most aggressive malignant tumor with limited treatment alternatives post metastasis. Vernodalin (VN) induced apoptosis has been reported in various types of human cancer cells. However, the precise molecular mechanisms underlying the anti-metastasis action of VN on GC cells are yet to be elucidated. Objective: In this study, we investigated the anti-metastatic and apoptotic effects of VN on SGC- 7901 and AGS cells, with a purpose of gaining a deeper understanding of the anti-metastatic mechanisms of VN on gastric carcinoma. To attenuate the activation of PI3K/AKT/mTOR and mitogen-activated protein kinase (MAPK) signaling pathways by VN in GC cells. Methods: We employed VN and gastric cancer cells in experiments such as MTT assay, apoptosis, MMP, DAPI, Rh-123, cell adhesion assay, and western blot analysis on GC SGC-7901 and AGS cells. Results: Our results revealed that VN inhibits cell proliferation, adhesion, and metastasis and induces apoptosis of both GC cells. VN potentially reduced the protein expressions of MMP-2, MMP-9, and uPA, whereas intensified expressions of TIMP-1 and TIMP-2. Also, VN attenuates the expression of FAK, p-PI3K, p-AKT, p-mTOR, p-JNK, p-p38MAPK, and p-ERK. Thus, it is inferred that VN treatment reduced the activities of MMP-2 and MMP-9 via the FAK/PI3K/AKT/ mTOR, and MAPKs signaling pathways. Our results confirm that VN prevented GC growth, invasion and metastasis and induce apoptosis in GC cells. Conclusion: Our findings suggest that VN is a potential natural therapeutic compound as a new remedy for GC chemotherapy treatment.