Ganoderma lucidum: Multifaceted mechanisms to combat diabetes through polysaccharides and triterpenoids: A comprehensive review

Diabetes is a chronic metabolic disorder. Diabetes complications can affect many organs and systems in the body. Ganoderma lucidum (G. lucidum) contains various compounds that have been studied for their potential antidiabetic effects, including polysaccharides, triterpenoids (ganoderic acids, ganoderol B), proteoglycans, and G. lucidum extracts. G. lucidum polysaccharides (GLPs) and triterpenoids have been shown to act through distinct mechanisms, such as improving glucose metabolism, modulating the mitogen-activated protein kinase (MAPK) system, inhibiting the nuclear factor-kappa B (NF-κB) pathway, and protecting the pancreatic beta cells. While GLPs exhibit a significant role in controlling diabetic nephropathy and other associated complications. This review states the G. lucidum antidiabetic mechanisms of action and potential biologically active compounds that contribute to diabetes management and associated complications. To make G. lucidum an appropriate replacement for the treatment of diabetes with fewer side effects, more study is required to completely comprehend the number of physiologically active compounds present in it as well as the underlying cellular mechanisms that influence their effects on diabetes.

Pesticides impacts on human health and the environment with their mechanisms of action and possible countermeasures

Pesticides are chemical constituents used to prevent or control pests, including insects, rodents, fungi, weeds, and other unwanted organisms. Despite their advantages in crop production and disease management, the use of pesticides poses significant hazards to the environment and public health. Pesticide elements have now perpetually entered our atmosphere and subsequently contaminated water, food, and soil, leading to health threats ranging from acute to chronic toxicities. Pesticides can cause acute toxicity if a high dose is inhaled, ingested, or comes into contact with the skin or eyes, while prolonged or recurrent exposure to pesticides leads to chronic toxicity. Pesticides produce different types of toxicity, for instance, neurotoxicity, mutagenicity, carcinogenicity, teratogenicity, and endocrine disruption. The toxicity of a pesticide formulation may depend on the specific active ingredient and the presence of synergistic or inert compounds that can enhance or modify its toxicity. Safety concerns are the need of the hour to control contemporary pesticide-induced health hazards. The effectiveness and implementation of the current legislature in providing ample protection for human health and the environment are key concerns. This review explored a comprehensive summary of pesticides regarding their updated impacts on human health and advanced safety concerns with legislation. Implementing regulations, proper training, and education can help mitigate the negative impacts of pesticide use and promote safer and more sustainable agricultural practices.

Night eating and its relationship with BMI, stress, sleep quality and duration of study among university students

INTRODUCTION

Night eating is a very common dietary behaviour among university students. This study aims to investigate the relationship between night eating and BMI, stress, sleep quality and duration of study among university students.

MATERIALS AND METHODS

A total of 385 university students including foundation and undergraduate students took part in this study. Self-administered online surveys were used to obtain sociodemographic data, and anthropometry measurements including weight and height, night eating during studying, duration of the study, opinion on eating and academic performance, sleep quality, level of depression, anxiety, and stress of the respondents. Questionnaires were validated and IBM SPSS Statistics Software version 26.0 was used to analyse categorical and continuous variables.

RESULTS

The findings showed that there was an association between night eaters and coffee consumption with BMI (p<0.001) and sleep quality (p<0.05). However, there was no association (p>0.05) found between the types of food eaten during night studying and the mean duration of the study. The results showed drinking coffee had an association with depression, anxiety, and stress (p<0.05) among Malaysian university students.

CONCLUSION

Coffee consumption was common among undergraduate students during studying. Awareness of the risk of overconsumption of caffeine intake should be implemented in the future. However, this study did not include all types of food choices and drinks. Thus, frequency of eating energy dense food during night studying among students should be conducted in the future.

Ganoderma lucidum: Insight into antimicrobial and antioxidant properties with development of secondary metabolites

Ganoderma lucidum is a versatile mushroom. Polysaccharides and triterpenoids are the major bioactive compounds and have been used as traditional medicinal mushrooms since ancient times. They are currently used as nutraceuticals and functional foods. G. lucidum extracts and their bioactive compounds have been used as an alternative to antioxidants and antimicrobial agents. Secondary metabolites with many medicinal properties make it a possible substitute that could be applied as immunomodulatory, anticancer, antimicrobial, anti-oxidant, anti-inflammatory, and anti-diabetic. The miraculous properties of secondary metabolites fascinate researchers for their development and production. Recent studies have paid close attention to the different physical, genetic, biochemical, and nutritional parameters that potentiate the production of secondary metabolites. This review is an effort to collect biologically active constituents from G. lucidum that reveal potential actions against diseases with the latest improvement in a novel technique to get maximum production of secondary metabolites. Studies are going ahead to determine the efficacy of numerous compounds and assess the valuable properties achieved by G. lucidum in favor of antimicrobial and antioxidant outcomes.

Positive and negative aspects of bacteriophages and their immense role in the food chain

Bacteriophages infect and replicate inside a bacterial host as well as serve as natural bio-control agents. Phages were once viewed as nuisances that caused fermentation failures with cheese-making and other industrial processes, which lead to economic losses, but phages are now increasingly being observed as being promising antimicrobials that can fight against spoilage and pathogenic bacteria. Pathogen-free meals that fulfil industry requirements without synthetic additives are always in demand in the food sector. This study introduces the readers to the history, sources, and biology of bacteriophages, which include their host ranges, absorption mechanisms, lytic profiles, lysogenic profiles, and the influence of external factors on the growth of phages. Phages and their derivatives have emerged as antimicrobial agents, biodetectors, and biofilm controllers, which have been comprehensively discussed in addition to their potential applications in the food and gastrointestinal tract, and they are a feasible and safe option for preventing, treating, and/or eradicating contaminants in various foods and food processing environments. Furthermore, phages and phage-derived lytic proteins can be considered potential antimicrobials in the traditional farm-to-fork context, which include phage-based mixtures and commercially available phage products. This paper concludes with some potential safety concerns that need to be addressed to enable bacteriophage use efficiently.

Islamic Perspectives on Polygenic Testing and Selection of IVF Embryos (PGT-P) for Optimal Intelligence and Other Non-Disease-Related Socially Desirable Traits

In recent years, the genetic testing and selection of IVF embryos, known as preimplantation genetic testing (PGT), has gained much traction in clinical assisted reproduction for preventing transmission of genetic defects. However, a more recent ethically and morally controversial development in PGT is its possible use in selecting IVF embryos for optimal intelligence quotient (IQ) and other non-disease-related socially desirable traits, such as tallness, fair complexion, athletic ability, and eye and hair colour, based on polygenic risk scores (PRS), in what is referred to as PGT-P. Artificial intelligence (AI) and machine learning-based analysis of big data sets collated from genome sequencing of specific human ethnic populations can be used to estimate an individual embryo's likelihood of developing such multifactorial traits by analysing the combination of specific genetic variants within its genome. Superficially, this technique appears compliant with Islamic principles and ethics. Because there is no modification of the human genome, there is no tampering with Allah's creation (taghyīr khalq Allah). Nevertheless, a more critical analysis based on the five maxims of Islamic jurisprudence (qawa'id fiqhiyyah) that are often utilized in discourses on Islamic bioethics, namely qaṣd (intention), yaqın̄ (certainty), ḍarar (injury), ḍarūra (necessity), and `urf (custom), would instead reveal some major ethical and moral flaws of this new medical technology in the selection of non-disease-related socially desirable traits, and its non-compliance with the spirit and essence of Islamic law (shariah). Muslim scholars, jurists, doctors, and biomedical scientists should debate this further and issue a fatwa on this new medical technology platform.

Sclareol exerts synergistic antidepressant effects with quercetin and caffeine, possibly suppressing GABAergic transmission in chicks

This study evaluated the effects of sclareol (SCL) with or without caffeine (CAF) and quercetin (QUR) using in-vivo and in-silico studies. For this, 5-day-old chicks weighing between 45 and 48 g were randomly divided into five groups and treated accordingly. The chicks were monitored to compare the occurrence, latency, and duration of sleep as well as the loss and gain of righting reflex in response to SCL-10 mg/kg, CAF-10 mg/kg, and QUR-50 mg/kg using a thiopental sodium (TS)-induced sleeping model. Data were analyzed by one-way ANOVA followed by t-Student-Newman-Keuls' as a posthoc test at 95% confidence intervals with multiple comparisons. An in-silico study was also performed to investigate the possible antidepressant mechanisms of the test and/or standard drugs with different subunits of GABAA receptors. In comparison to the SCL, CAF, and QUR individual groups, SCL+CAF+QUR significantly increased the latency while decreasing the length of sleep. The incidence of loss and gain of the righting reflex was also modulated in the combination group. SCL showed better interaction with GABAA (α2 and α5) subunits than QUR with α2, α3, and α5. All these compounds showed stronger interactions with the GABAA receptor subunits than the standard CAF. Taken together, SCL, CAF, and QUR reduced the TS-induced righting reflex and sleeping time in the combination group more than in the individual treatments. SCL may show its antidepressant effects, possibly through interactions with GABAA receptor subunits.

Controlling Intestinal Infections and Digestive Disorders Using Probiotics

After consumption, probiotics provide health benefits to the host. Probiotics and their metabolites have therapeutic and nutritional properties that help to alleviate gastrointestinal, neurological, and cardiovascular problems. Probiotics strengthen host immunity through various mechanisms, including improved gut barrier function, receptor site blocking, competitive exclusion of pathogens, and the production of bioactive molecules. Emerging evidence suggests that intestinal bowel diseases can be fatal, but regular probiotic consumption can alleviate disease symptoms. The use and detailed description of the health benefits of probiotics to consumers in terms of reducing intestinal infection, inflammation, and digestive disorders are discussed in this review. The well-designed and controlled studies that examined the use of probiotics to reduce life-threatening activities caused by intestinal bowel diseases are also covered. This review discussed the active principles and potency of probiotics as evidenced by the known effects on host health, in addition to providing information on the mechanism of action.

Biogenic nanoparticles from waste fruit peels: Synthesis, applications, challenges and future perspectives

Nanotechnology is a continually growing field with a wide range of applications from food science to biotechnology and nanobiotechnology. As the current world is grappling with non-biodegradable waste, considered more challenging and expensive to dispose of than biodegradable waste, new technologies are needed today more than ever. Modern technologies, especially nanotechnology, can transform biodegradable waste into products for human use. Researchers are exploring sustainable pathways for nanotechnology by utilizing biodegradable waste as a source for preparing nanomaterials. Over the past ten years, the biogenic production of metallic nanoparticles (NPs) has become a promising alternative technique to traditional NPs synthesis due to its simplicity, eco-friendliness, and biocompatibility in nature. Fruit and vegetable waste (after industrial processing) contain various bioactives (such as flavonoids, phenols, tannins, steroids, triterpenoids, glycosides, anthocyanins, carotenoids, ellagitannins, vitamin C, and essential oils) serving as reducing and capping agents for NP synthesis and they possess antibacterial, antioxidant, and anti-inflammatory properties. This review addresses various sources of biogenic NPs including their synthesis using fruit/vegetable waste, types of biogenic NPs, extraction processes and extracted biomaterials, the pharmacological functionality of NPs, industrial aspects, and future perspectives. In this manner, this review will cover the most recent research on the biogenic synthesis of NPs from fruit/vegetable peels to transform them into therapeutic nanomedicines.

Cellular, Molecular, Pharmacological, and Nano-Formulation Aspects of Thymoquinone-A Potent Natural Antiviral Agent

The goal of an antiviral agent research is to find an antiviral drug that reduces viral growth without harming healthy cells. Transformations of the virus, new viral strain developments, the resistance of viral pathogens, and side effects are the current challenges in terms of discovering antiviral drugs. The time has come and it is now essential to discover a natural antiviral agent that has the potential to destroy viruses without causing resistance or other unintended side effects. The pharmacological potency of thymoquinone (TQ) against different communicable and non-communicable diseases has been proven by various studies, and TQ is considered to be a safe antiviral substitute. Adjunctive immunomodulatory effects in addition to the antiviral potency of TQ makes it a major compound against viral infection through modulating the production of nitric oxide and reactive oxygen species, decreasing the cytokine storm, and inhibiting endothelial dysfunction. Nevertheless, TQ's low oral bioavailability, short half-life, poor water solubility, and conventional formulation are barriers to achieving its optimal pharmacologic benefits. Nano-formulation proposes numerous ways to overcome these obstacles through a small particle size, a big surface area, and a variety of surface modifications. Nano-based pharmaceutical innovations to combat viral infections using TQ are a promising approach to treating surmounting viral infections.

Ganoderma lucidum: Novel Insight into Hepatoprotective Potential with Mechanisms of Action

Ganoderma lucidum (G. lucidum) has been widely used for its health benefits as an edible and traditional medicinal mushroom for thousands of years in Asian countries. It is currently used as a nutraceutical and functional food owing to its major bioactive compounds, polysaccharides and triterpenoids. G. lucidum exhibits a broad range of hepatoprotective impacts in various liver disorders, such as hepatic cancer, nonalcoholic fatty liver disease (NAFLD), alcohol-induced liver disease, hepatitis B, hepatic fibrosis, and liver injury induced by carbon tetrachloride (CCl4) and α-amanitin. G. lucidum protects the liver through a broad range of mechanisms that include the modulation of liver Phase I and II enzymes, the suppression of β-glucuronidase, antifibrotic and antiviral actions, the regulation of the production of nitric oxide (NO), the maintenance of hepatocellular calcium homeostasis, immunomodulatory activity, and scavenging free radicals. G. lucidum could signify an encouraging approach for the management of various chronic hepatopathies, and its potential mechanisms make it a distinctive agent when used alone or with other drugs and applied as a functional food, nutraceutical supplement, or adjuvant to modern medicine. This review summarizes the hepatoprotective properties of G. lucidum with its various mechanisms of action on different liver ailments. Biologically active substances derived from G. lucidum are still being studied for their potential benefits in treating different liver ailments.

Mechanisms of Actions Involved in The Antinociceptive Effect of Estragole and its β-Cyclodextrin Inclusion Complex in Animal Models

(1) Background: estragole is a monoterpene found in the essential oils of several aromatic plants, which can be used for several pharmacological activities. The aim of this study was to evaluate the antinociceptive effect of estragole (Es) and its β-cyclodextrins inclusion complex (Es/β-CD). (2) Methods: the effects of Es and Es/β-CD on the central nervous system (CNS) were evaluated through open field and rota-rod assays, and the antinociceptive effect in formalin models, abdominal writhing induced by acetic acid, hot plate, tail flick test and plantar mechanical hyperalgesia. (3) Results: Es and Es/β-CD showed no alterations on the CNS evaluated parameters and the results suggested there was an antinociceptive action in the formalin, abdominal writhing, hot plate, tail flick tests and plantar mechanical hyperalgesia, proposing the involvement of the nitric oxide, glutamatergic signaling pathways, cyclic guanosine monophosphate and vanilloid pathways. (4) Conclusion: the results suggest that Es and Es/β-CD have a promising antinociceptive potential as a possible alternative for the pharmacological treatment of pain, also showing that the encapsulation of Es in β-cyclodextrins probably improves its pharmacological properties, since the complexation process involves much lower amounts of the compound, contributing to better bioavailability and a lower probability of adverse effect development.

Pharmacological Efficacy of Probiotics in Respiratory Viral Infections: A Comprehensive Review

Mortality and morbidity from influenza and other respiratory viruses are significant causes of concern worldwide. Infections in the respiratory tract are often underappreciated because they tend to be mild and incapacitated. On the other hand, these infections are regarded as a common concern in clinical practice. Antibiotics are used to treat bacterial infections, albeit this is becoming more challenging since many of the more prevalent infection causes have acquired a wide range of antimicrobial resistance. Resistance to frontline treatment medications is constantly rising, necessitating the development of new antiviral agents. Probiotics are one of several medications explored to treat respiratory viral infection (RVI). As a result, certain probiotics effectively prevent gastrointestinal dysbiosis and decrease the likelihood of secondary infections. Various probiotic bacterias and their metabolites have shown immunomodulating and antiviral properties. Unfortunately, the mechanisms by which probiotics are effective in the fight against viral infections are sometimes unclear. This comprehensive review has addressed probiotic strains, dosage regimens, production procedures, delivery systems, and pre-clinical and clinical research. In particular, novel probiotics’ fight against RVIs is the impetus for this study. Finally, this review may explore the potential of probiotic bacterias and their metabolites to treat RVIs. It is expected that probiotic-based antiviral research would be benefitted from this review’s findings.

Arsenic Exposure through Dietary Intake and Associated Health Hazards in the Middle East

Dietary arsenic (As) contamination is a major public health issue. In the Middle East, the food supply relies primarily on the import of food commodities. Among different age groups the main source of As exposure is grains and grain-based food products, particularly rice and rice-based dietary products. Rice and rice products are a rich source of core macronutrients and act as a chief energy source across the world. The rate of rice consumption ranges from 250 to 650 g per day per person in South East Asian countries. The source of carbohydrates through rice is one of the leading causes of human As exposure. The Gulf population consumes primarily rice and ready-to-eat cereals as a large proportion of their meals. Exposure to arsenic leads to an increased risk of non-communicable diseases such as dysbiosis, obesity, metabolic syndrome, diabetes, chronic kidney disease, chronic heart disease, cancer, and maternal and fetal complications. The impact of arsenic-containing food items and their exposure on health outcomes are different among different age groups. In the Middle East countries, neurological deficit disorder (NDD) and autism spectrum disorder (ASD) cases are alarming issues. Arsenic exposure might be a causative factor that should be assessed by screening the population and regulatory bodies rechecking the limits of As among all age groups. Our goals for this review are to outline the source and distribution of arsenic in various foods and water and summarize the health complications linked with arsenic toxicity along with identified modifiers that add heterogeneity in biological responses and suggest improvements for multi-disciplinary interventions to minimize the global influence of arsenic. The development and validation of diverse analytical techniques to evaluate the toxic levels of different As contaminants in our food products is the need of the hour. Furthermore, standard parameters and guidelines for As-containing foods should be developed and implemented.

Gastroprotective effect of low dose Eugenol in experimental rats against ethanol induced toxicity: Involvement of antiinflammatory and antioxidant mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Syzygium aromaticum L. volatile oil (clove oil) has been traditionally used for various stomach disorders including inflammatory conditions. Eugenol is the major constituent present in the volatile oil, and it has been established as a gastroprotective agent through many published studies, but the exact and complete mechanism of ulcer protection is not delineated yet. Moreover, it plays precisely the opposite effect in higher dose in antiulcer properties with worsening the ulcer at a higher dose.

AIM

This study aims to carry out the prophylactic cytoprotective effect of eugenol with single low doses and explore the probable interrelated underlying transcriptional and translational level mechanism of cytoprotection such as antioxidative, anti-inflammatory, mucous generation in rats using ethanol-induced ulcer model.

METHODS

Rats were administered with different doses of eugenol before ethanol intragastrically. The effects of the eugenol on mucous production, Nitric oxide generation, PGE2 synthesis, lipid peroxidation were recorded together with cytokines measurement in the blood. TNF-α and IL-6, two key cytokines, were also studied in specific. In addition, studies on the immunohistochemical and gene expression of HSP70 and iNOS indicators have been conducted.

RESULTS

According to our findings, Eugenol substantially reduced the ulcer index and completely protected the mucosa from lesions. By restoring the lowered GSH and NP-SH levels, the protective effect of the eugenol was found to be augmented at both doses. This finding has corresponded to an increase in MDA, which was lowered by ethanol administration. Pre-treatment with eugenol on the ethanol-induced ulcer reduced the plasma NO levels and increased PGE2 along with a decreased TNF-α and IL-6 concentration. Additionally, significant transcriptional and translational upregulation of HSP70 and downregulation of iNOS were detected in the eugenol-treated rat stomach tissue.

CONCLUSION

Our findings demonstrated that eugenol had a considerable gastroprotective impact at low doses, which could be attributed to its ability to regulate inflammatory reactions and antioxidant capacity.

Advancement and New Trends in Analysis of Pesticide Residues in Food: A Comprehensive Review

Food safety is a rising challenge worldwide due to the expanding population and the need to produce food to feed the growing population. At the same time, pesticide residues found in high concentrations in fresh agriculture pose a significant threat to food safety. Presently, crop output is being increased by applying herbicides, fungicides, insecticides, pesticides, fertilizers, nematicides, and soil amendments. A combination of factors, including bioaccumulation, widespread usage, selective toxicity, and stability, make pesticides among the most toxic compounds polluting the environment. They are especially harmful in vegetables and fruits because people are exposed to them. Thus, it is critical to monitor pesticide levels in fruits and vegetables using all analytical techniques available. Any evaluation of the condition of pesticide contamination in fruits and vegetables necessitates knowledge of maximum residue levels (MRLs). We set out the problems in determining various types of pesticides in vegetables and fruits, including the complexity and the diversity of matrices in biological materials. This review examines the different analytical techniques to determine the target analytes that must be isolated before final consumption. Many processes involved determining pesticide residues in fruits and vegetables and their advantages and disadvantages have been discussed with recommendations. Furthermore, MRLs of target pesticide residues in fruit and vegetable samples are discussed in the context of data from the literature. The review also examines MRLs' impact on the international trade of fruits and vegetables. Accurate, sensitive, and robust analytical procedures are critical to ensuring that pesticide levels in food products are effectively regulated. Despite advances in detection technology, effective sample preparation procedures for pesticide residue measurement in cereals and feedstuffs are still needed. In addition, these methods must be compatible with current analytical techniques. Multi-residue approaches that cover a wide range of pesticides are desired, even though pesticides' diverse natures, classes, and physio-chemical characteristics make such methods challenging to assemble. This review will be valuable to food analysts and regulatory authorities to monitor the quality and safety of fresh food products.

Effect of Exercises on Central and Endocrine System for Pain Modulation in Primary Dysmenorrhea

Dysmenorrhea is the term for describing complex menstrual flow and painful spasmodic cramps during menstruation, and pain without any pathology is considered Primary Dysmenorrhea (PD). It is the most frequent ailment among women of all ages and races. The pain is dull and throbbing in character and occurs in the lower back and abdomen. Symptoms commonly appear 6 to 12 months after menarche, with the most significant incidence in the late teen and early twenties. Physical exercise is nearly a new non-medical intervention to relieve PD associated pain. Aerobics, stretching and Resistive exercises for 8-12 weeks, either supervised or unsupervised, relieves pain. Exercises are believed to cause hormonal changes in the uterine lining, which reduces PD symptoms. Researchers have presumed different pain-relieving methods, ranging from non-opioids to opioids to hormonal for variations in pain sensitivity. Exercise-induced analgesia provides the central pathway as the primary mechanism for pain reduction while, another way to reducing pain in PD may be a hormonal interaction. The hormonal changes causing exercise-induced pain modulation during the menstruation cycle is not clearly understood and the interaction and activation of all the central and endocrine components, which is a complex mechanism, is also not explained clearly. This study briefly reviews the physiological mechanism of Exercise-induced analgesia and its potent roles in controlling the pathogenesis of PD for pain relief.

Comparative analysis of IVF-ICSI outcomes between advanced and early stage of endometriosis stimulated with HMG

INTRODUCTION

Endometriosis is a challenging disease to treat, and patients may eventually need in vitro fertilisation with Intracytoplasmic sperm injection (IVF/ICSI) to conceive after other modalities failed. There are inconsistent outcomes of IVF performance in patients with endometriosis especially with highly purified human menotropin gonadotrophin (hMG). This study was commenced to determine whether the use of hMG affects the IVF outcome in different stage of endometriosis.

MATERIALS AND METHODS

This is an observational study. Eighty-seven women who had endometriosis confirmed surgically and underwent IVF/ICSI treatment, stimulated with hMG alone were included. Based on the revised American Society for Reproductive Medicine (rASRM), the participants were classified as early endometriosis (I/II) (n=39) or advanced endometriosis (III/IV) (n=35). The main outcome measures used were clinical pregnancy rate.

RESULTS

Women with advanced endometriosis had a lower oocyte yield, less good quality day-3 embryos and lower clinical pregnancy rate compared with the mild endometriosis. However, higher fertilisation rate were recorded in advanced stage endometriosis compared to milder disease.

CONCLUSIONS

The rASRM classification of endometriosis is valuable in predicting IVF outcome as advanced endometriosis performs poorly compared to a milder disease. Highly purified hMG could be an alternative as an ovarian stimulation in endometriosis.

Glycyrrhiza glabra (Licorice): A Comprehensive Review on Its Phytochemistry, Biological Activities, Clinical Evidence and Toxicology

There are more than 30 species of Glycyrrhiza genus extensively spread worldwide. It was the most prescribed herb in Ancient Egyptian, Roman, Greek, East China, and the West from the Former Han era. There are various beneficial effects of licorice root extracts, such as treating throat infections, tuberculosis, respiratory, liver diseases, antibacterial, anti-inflammatory, and immunodeficiency. On the other hand, traditional medicines are getting the attraction to treat many diseases. Therefore, it is vital to screen the medicinal plants to find the potential of new compounds to treat chronic diseases such as respiratory, cardiovascular, anticancer, hepatoprotective, etc. This work comprehensively reviews ethnopharmacological uses, phytochemistry, biological activities, clinical evidence, and the toxicology of licorice, which will serve as a resource for future clinical and fundamental studies. An attempt has been made to establish the pharmacological effect of licorice in different diseases. In addition, the focus of this review article is on the molecular mechanism of licorice extracts and their four flavonoids (isoliquiritigenin, liquiritigenin, lichalocone, and glabridin) pharmacologic activities. Licorice could be a natural alternative for current therapy to exterminate new emerging disorders with mild side effects. This review will provide systematic insights into this ancient drug for further development and clinical use.

A current novel perspective approach for coronavirus disease-2019 pandemic outbreak

Coronavirus disease-2019 is a serious health threat around the globe. Across the world, approximately 142 million people were infected, and three million deaths happened. The fast propagation is also associated with constant anxiety, mental stress, and discomfort in public and health-care professionals. Lack of approved drugs regimen to combat the pandemic challenge concretely is a challenging project for all who are committed to developing remedial assistance. However, the successful development of three vaccines gives a solid roadmap to combat this disease. In this review, we highlighted the current development and challenges of this pandemic.

Current trends and future perspectives of nanomedicine for the management of colon cancer

Colon cancer (CC) kills countless people every year throughout the globe. It persists as one of the highly lethal diseases to be treated because the overall survival rate for CC is meagre. Early diagnosis and efficient treatments are two of the biggest hurdles in the fight against cancer. In the present work, we will review thriving strategies for CC targeted drug delivery and critically explain the most recent progressions on emerging novel nanotechnology-based drug delivery systems. Nanotechnology-based animal and human clinical trial studies targeting CC are discussed. Advancements in nanotechnology-based drug delivery systems intended to enhance cellular uptake, improved pharmacokinetics and effectiveness of anticancer drugs have facilitated the powerful targeting of specific agents for CC therapy. This review provides insight into current progress and future opportunities for nanomedicines as potential curative targets for CC treatment. This information could be used as a platform for the future expansion of multi-functional nano constructs for CC's advanced detection and functional drug delivery.

Cell viability and electrical response of breast cancer cell treated in aqueous graphene oxide solution deposition on interdigitated electrode

Breast cancer is one of the most reported cancers that can lead to death. Despite the advances in diagnosis and treatment procedures, the possibility of cancer recurrences is still high in many cases. With that in consideration, researchers from all over the world are showing interest in the unique features of Graphene oxide (GO), such as its excellent and versatile physicochemical properties, to explore further its potential and benefits towards breast cancer cell treatment. In this study, the cell viability and electrical response of GO, in terms of resistivity and impedance towards the breast cancer cells (MCF7) and normal breast cells (MCF10a), were investigated by varying the pH and concentration of GO. Firstly, the numbers of MCF7 and MCF10a were measured after being treated with GO for 24 and 48 h. Next, the electrical responses of these cells were evaluated by using interdigitated gold electrodes (IDEs) that are connected to an LCR meter. Based on the results obtained, as the pH of GO increased from pH 5 to pH 7, the number of viable MCF7 cells decreased while the number of viable MCF10a slightly increased after the incubation period of 48 h. Similarly, the MCF7 also experienced higher cytotoxicity effects when treated with GO concentrations of more than 25 µg/mL. The findings from the electrical characterization of the cells observed that the number of viable cells has corresponded to the impedance of the cells. The electrical impedance of MCF7 decreased as the number of highly insulating viable cell membranes decreased. But in contrast, the electrical impedance of MCF10a increased as the number of highly insulating viable cell membranes increased. Hence, it can be deduced that the GO with higher pH and concentration influence the MCF7 cancer cell line and MCF10a normal breast cell.

Fertility preservation opportunities for cancer patients in Malaysia

Fertility preservation is significant for oncology patients to maintain their ability to start a family when they are ready. Onco-fertility, as a discipline, exists at the intersection of oncology and reproductive medicine that safeguards and expands the fertility options for cancer survivors, by facilitating early intervention and suitable treatment with favourable outcomes. Successful fertility preservation requires a comprehensive networking among the gynaecologists, oncologists, pathologists, imaging and other specialists, involved in diagnosing and treating cancer in the reproductive age group. There are several ways in which fertility can be preserved, like role of gonadotrophin releasing hormone analogues, in vitro maturation, and cryopreservation.

Effectiveness of Azithromycin as add-on Therapy in COVID-19 Management

As winter is knocking the door, the risk of respiratory tract infection is increasing at present scenario due to no prophylaxis of Covid-19. So, no one is safe until everyone is safe. Worldwide researchers are looking for the vaccine to remove the need for social distancing, mask-wearing and social gathering. A vaccine is like many other outcomes if the vaccine would be available; we cannot say about the effectiveness of the vaccine. Several drugs are testing to save the people life from pandemic; azithromycin is one of them. This work is a review article with the updated findings of azithromycin in the context of COVID-19. The option of azithromycin with regards to COVID-19 is justified by its anti-inflammatory, immunomodulatory, and anti-fibrotic effects and their pharmacokinetic properties, leading to effective concentrations in the target tissue. Azithromycin tends to be an effective candidate for SARS-CoV-2 replication inhibition that block the initial stage of the viral life cycle. Clinical trials at a preliminary scale and final stage show the significant results of azithromycin in supportive care therapy. Azithromycin was an early candidate for the medication of Covid-19 with or without hydroxychloroquine. It is exercised mostly as an outpatient antibiotic in COVID-19. In summing-up, any primary anti-viral and antibiotic treatment is not the only possibility of fighting COVID-19 pharmacologically. It will be an injustice with them who require broader spectrum antibiotic if we do not exercise azithromycin to them. So significant research priority is needed to determine whether azithromycin is useful in the treatment of COVID-19.

An updated knowledge of Black seed (Nigella sativa Linn.): Review of phytochemical constituents and pharmacological properties

N. sativa (N. sativa) has been used since ancient times, when a scientific concept about the use of medicinal plants for the treatment of human illnesses and alleviation of their sufferings was yet to be developed. It has a strong religious significance as it is mentioned in the religious books of Islam and Christianity. In addition to its historical and religious significance, it is also mentioned in ancient medicine. It is widely used in traditional systems of medicine for a number of diseases including asthma, fever, bronchitis, cough, chest congestion, dizziness, paralysis, chronic headache, back pain and inflammation. The importance of this plant led the scientific community to carry out extensive phytochemical and biological investigations on N. sativa. Pharmacological studies on N. sativa have confirmed its antidiabetic, antitussive, anticancer, antioxidant, hepatoprotective, neuro-protective, gastroprotective, immunomodulator, analgesic, antimicrobial, anti-inflammatory, spasmolytic, and bronchodilator activity. The present review is an effort to explore the reported chemical composition and pharmacological activity of this plant. It will help as a reference for scientists, researchers, and other health professionals who are working with this plant and who need up to date knowledge about it.

Ganoderma lucidum: A rational pharmacological approach to surmount cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum (G. lucidum) has been broadly used for health endorsement as well as longevity for over 2000 years in Asian countries. It is an example of an ancient remedy and known as immortality mushroom. It has been employed as a health promoting agent owing to its broad pharmacological and therapeutical approaches. It has been confirmed that G. lucidum exhibits significant potency to prevent and treat different types of cancers such as breast, prostate, colon, lung and cervical.

AIM OF THE STUDY

To explore anticancer effects of various pharmacologically active compounds obtained from G. lucidum and their possible mechanism of action.

MATERIALS AND METHODS

A literature search was conducted using PubMed, Goggle Scholar, Saudi Digital Library and Cochrane Library until October 11, 2019. Search was made by using keywords such as anticancer evidence, mechanism of action, pharmacology, antioxidant, toxicity, chemotherapy, triterpenoids and polysaccharides of G. lucidum.

RESULTS

Various chemical compounds from G. lucidum exhibit anticancer properties mainly through diverse mechanism such as cytotoxic properties, host immunomodulators, metabolizing enzymes induction, prohibit the expression of urokinase plasminogen activator (uPA) and urokinase plasminogen activator receptor (uPAR) in cancer cells. Among the various compounds of G. lucidum triterpenoids and polysaccharides are under the major consideration of studies due to their several evidence of preclinical and clinical studies against cancer.

CONCLUSION

Natural alternatives associated with mild side effects are the basic human need of present therapy to eradicate the new emerging disorders. This review is an attempt to compile pharmacologically active compounds of G. lucidum those exhibit anti cancer effects either alone or along with chemotherapy and anticancer mechanisms against various cancer cells, clinical trials, chemotherapy induced toxicity challenges with limitations. It acts as a possible substitute to combat cancer growth with advance and conventional combination therapies as natural alternatives.

Studies of the p53 gene mutation in Saudi non-Hodgkin's lymphoma

Tumor biopsies (paraffin embedded tissue) obtained from 45 Saudi patients with non-Hodgkin's lymphoma (NHL) were examined for the incidence of p53 mutations screened by polymerase chain reaction (PCR) and single strand conformation polymorphism (SSCP) analysis. DNA sequencing was carried out to confirm the occurrence of p53 mutation in PCR products showing abnormal migration by SSCP analysis. Only 1/45 samples showed the incidence of a homozygous mutation at codon 179 (exon 5) of the p53 gene that replaces histidine with tyrosine. The data showed that the frequency of p53 mutations was very low in Saudi NHL. Our results are consistent with the general observation that the p53 mutation is rather infrequent in hematopoietic malignancies like NHLs.

The stress-activated protein kinase subfamily of c-Jun kinases

The mitogen-activated protein (MAP) kinases Erk-1 and Erk-2 are proline-directed kinases that are themselves activated through concomitant phosphorylation of tyrosine and threonine residues. The kinase p54 (M(r) 54,000), which was first isolated from cycloheximide-treated rats, is proline-directed like Erks-1/2, and requires both Tyr and Ser/Thr phosphorylation for activity. p54 is, however, distinct from Erks-1/2 in its substrate specificity, being unable to phosphorylate pp90rsk but more active in phosphorylating the c-Jun transactivation domain. Molecular cloning of p54 reveals a unique subfamily of extracellularly regulated kinases. Although they are 40-45% identical in sequence to Erks-1/2, unlike Erks-1/2 the p54s are only poorly activated in most cells by mitogens or phorbol esters. However, p54s are the principal c-Jun N-terminal kinases activated by cellular stress and tumour necrosis factor (TNF)-alpha, hence they are designated stress-activated protein kinases, or SAPKs. SAPKs are also activated by sphingomyelinase, which elicits a subset of cellular responses to TNF-alpha (ref. 9). SAPKs therefore define a new TNF-alpha and stress-activated signalling pathway, possibly initiated by sphingomyelin-based second messengers, which regulates the activity of c-Jun.

No mutations in the translated region of exon 1 in the TSH receptor in Graves' thyroid glands

We have amplified a 285 base pair by nested polymerase chain reaction 38 nucleotide downstream from the most 5' transcription initiation site (7) encoding 55 of the 57 residues of exon 1 of the human TSH receptor. These DNA were amplified from 10 tissue blocks of thyroid tissue removed at subtotal thyroidectomy from 10 patients with Graves' disease. The amplified 285 nucleotide fragments were sequenced in search of mutations in the coding region of exon 1 and polymorphism in the 120 nucleotides of the untranslated region upstream of the first ATG codon. No such variations were found. We conclude that the polymorphism or mutation of the part of the TSH receptor extracellular domain encoded by exon 1 and of sequences immediately upstream of the first ATG codon are not relevant to the pathogenesis of Graves' disease.

Regulation of an epitope-tagged recombinant Rsk-1 S6 kinase by phorbol ester and erk/MAP kinase

Phorbol ester tumor promoters (TPA) activate the endogenous erk/MAP kinases and Rsk S6 kinases but not the p70S6 kinase in COS cells. DNA sequences encoding the rat Rsk-1 S6 kinase (homologous to Xenopus rsk alpha), modified by insertion of a peptide epitope at the polypeptide aminoterminus, were expressed transiently in COS cells. TPA stimulates the 40S and peptide kinase activity of the recombinant epitope-tagged Rsk-1, as well as the extent of Rsk-1 autophosphorylation in vitro (32P-Ser >> 32P-Thr). Indications that the conformation of the recombinant Rsk-1 polypeptide is substantially changed after activation by TPA in situ include a retarded mobility of the Rsk-1 polypeptide on SDS-PAGE and the appearance of new 32P-peptides during autophosphorylation in vitro. All these features of the TPA-activated Rsk-1 S6 kinase are abolished by dephosphorylation of the kinase in vitro with Ser/Thr phosphatase-2A. TPA increases 32P incorporation into recombinant Rsk-1 by 2-3-fold (32P-Ser >> 32P-Thr). Peptide mapping exhibits a single major 32P-peptide in Rsk-1 isolated from unstimulated cells and 10-12 additional 32P peptides after TPA treatment in situ. Phosphorylation of basal or phosphatase-2A-treated recombinant Rsk-1 in vitro with erk2/MAP kinase increases Rsk-1 40S kinase, peptide kinase, and autophosphorylating activity, retards migration of Rsk-1 polypeptides on SDS-PAGE, and generates new sites of Rsk-1 autophosphorylation in vitro. By contrast, TPA-activated Rsk-1 is not altered in these properties by autophosphorylation in vitro. By contrast, TPA-activated Rsk-1 is not altered in these properties by phosphorylation in vitro with erk2/MAP kinase. Activation of Rsk-1 in situ with TPA diminishes by over 90% the extent of Rsk-1 phosphorylation achieved in vitro by erk2/MAP kinase, as compared to the parallel phosphorylation of a phosphatase-2A-treated Rsk-1; basal Rsk-1 is intermediate. Peptide maps of phosphatase-2A-treated Rsk-1 after phosphorylation in vitro with erk2/MAP kinase exhibit 32P-peptides that comigrate with nearly all of the 32P-peptides present in TPA-activated-32P Rsk-1 labeled in situ, plus several 32P-peptides characteristic of Rsk-1 autophosphorylation in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)

Human müllerian inhibiting substance: enhanced purification imparts biochemical stability and restores antiproliferative effects

Separation of copurifying protease activity from recombinant human Müllerian inhibiting substance (rhMIS) bound to a monoclonal antibody immunoaffinity column by a high-salt wash results in cleaner preparations of rhMIS resistant to cleavage upon storage. In addition, an inhibitor of rhMIS antiproliferative activity is removed. Proteolytic cleavages produced by either a copurifying protease or exogenous plasmin occur at residues 229 and 427 but do not abolish rhMIS biological activity. This report details the modified immunoaffinity column isolation protocol suitable for proteins such as rhMIS and describes the biochemical and antiproliferative properties of this protein.

Molecular structure of a major insulin/mitogen-activated 70-kDa S6 protein kinase

The molecular structure of a rat hepatoma 70-kDa insulin/mitogen-stimulated S6 protein kinase, obtained by molecular cloning, is compared to that of a rat homolog of the 85-kDa Xenopus S6 protein kinase alpha; both kinases were cloned from H4 hepatoma cDNA libraries. The 70-kDa S6 kinase (calculated molecular mass of 59,186 Da) exhibits a single catalytic domain that is most closely related in amino acid sequence (56% identity) to the amino-terminal, kinase C-like domain of the rat p85 S6 kinase (calculated molecular mass of 82,695 Da); strong similarity extends through a further 67 residues carboxyl-terminal to the catalytic domain (40% identity), corresponding to a region also conserved among the kinase C family. Outside of this segment of approximately 330 amino acids, the structures of the p70 and p85 S6 kinases diverge substantially. The p70 S6 kinase is known to be activated through serine/threonine phosphorylation by unidentified insulin/mitogen-activated protein kinases. A model for the regulation of p70 S6 protein kinase activity is proposed wherein the low activity of the unphosphorylated enzyme results from the binding of a basic, inhibitory pseudosubstrate site (located carboxyl-terminal to the extended catalytic domain) to an acidic substrate binding region (located amino-terminal to the catalytic domain); substrate binding is thereby prevented. S6 kinase activation requires displacement of this inhibitory segment, which is proposed to occur consequent to its multiple phosphorylation. The putative autoinhibitory segment contains several serine and threonine residues, each followed directly by a proline residue. This motif may prevent autophosphorylation but permit transphosphorylation; two of these serine residues reside in a maturation promoting factor (MPF)/cdc-2 consensus motif. Thus, hormonal regulation of S6 kinase may involve the action of MPF/cdc-2 or protein kinases with related substrate specificity.

Wegener's granulomatosis autoantigen is a novel neutrophil serine proteinase

Circulating IgG autoantibodies that produce cytoplasmic immunofluorescence staining of ethanol-fixed normal neutrophils have recently been found in a large percentage of patients with active Wegener's granulomatosis. Such autoantibodies are rarely found in other diseases and are therefore virtually diagnostic of Wegener's granulomatosis. The nature of the neutrophil antigen defined by these autoantibodies is controversial and the roles of the antigen and/or autoantibodies in the pathogenesis of Wegener's granulomatosis are unknown. We studied serum samples that produce the cytoplasmic pattern of staining from 10 patients with a diagnosis of Wegener's granulomatosis. By Western blot analysis, all 10 sera reacted with a 29-Kd neutrophil protein (p29). We generated a mouse monoclonal antibody directed against this antigen. The monoclonal antibody produced the same immunofluorescence staining pattern as the serum autoantibodies and was used to affinity-purify p29. The purified antigen had a novel N-terminal sequence homologous to members of the serine proteinase family and bound to radiolabeled diisopropyl fluorophosphate (DFP). We conclude that the neutrophil antigen responsible for the cytoplasmic staining pattern produced by autoantibodies in patients with active Wegener's granulomatosis is a distinctive serine proteinase.

Protein synthesis in yeast Saccharomyces cerevisiae. Purification of Co-eIF-2A and 'mRNA-binding factor(s)' and studies of their roles in Met-tRNAf.40S.mRNA complex formation

Antibodies prepared against a homogeneous preparation of Co-eIF-2A20 [Ahmad et al. (1985) J. Biol. Chem. 260, 6955-6959] reacted with several polypeptides including an 80-kDa polypeptide present in a crude yeast ribosomal salt wash. This 80-kDa polypeptide, containing Co-eIF-2A (Co-eIF-2A80) activity, has been extensively purified using a two-step purification procedure involving an immunoaffinity column chromatograph prepared using antibodies against Co-eIF-2A20 (fraction II) and hydroxyapatite chromatography (fraction III). The factors, eIF-2 + homogeneous Co-eIF-2A80 (fraction III) promoted Met-tRNAf.40S complex formation with an AUG codon but not with a physiological mRNA or a polyribonucleotide messenger poly(U,G) whereas eIF-2 + a partially purified Co-eIF-2A80 preparation (fraction II) promoted Met-tRNAf.40S complex formation with an AUG codon as well as with globin mRNA and poly(U,G) messenger. This factor-promoted Met-tRNAf binding to 40S ribosomes depends absolutely on the presence of a polyribonucleotide messenger containing an initiation codon (such as AUG or GUG). Other polyribonucleotide messengers tested, such as poly(U), poly(A) and poly(A,C) were completely ineffective in this binding reaction. This result indicates that the Met-tRNAf.40S.mRNA complex is formed by a direct interaction between Met-tRNAf, 40S ribosomes and the initiation site in mRNA. A mechanism has been proposed for Met-tRNAf.40S.mRNA complex formation in yeast.

A comparative study of the characteristics of eIF-2 and eIF-2-ancillary factor activities from yeast Saccharomyces cerevisiae and rabbit reticulocytes

The characteristics of yeast eukaryotic initiation factor 2 (eIF-2) and Co-eIF-2A have been studied and compared with those of the corresponding factors from rabbit reticulocytes. 1) Unlike eIF-2r, purified eIF-2y did not contain bound GDP. 2) Purified eIF-2y preparation contained GTPase activity and dephosphorylated GTP to GDP. 3) An anti-eIF-2r preparation which predominantly precipitated the gamma-subunit (Mr 54,000) of eIF-2r also precipitated the larger subunit (Mr 54,000) of eIF-2y. 4) Unlike eIF-2r, ternary complex formation by eIF-2y was not inhibited by Mg2+. 5) Both Co-eIF-2A20y and Co-eIF-2r significantly enhanced Met-tRNAf binding to eIF-2y and, again, Mg2+ did not have any effect on this stimulated Met-tRNAf binding to eIF-2y. 6) Both Co-eIF-2A20y and Co-eIF-2r were similarly effective in stimulating Met-tRNAf binding to eIF-2r in the absence of Mg2+. However, in the presence of Mg2+, Co-eIF-2A20y was significantly less effective than Co-eIF-2r as Co-eIF-2A20y did not promote displacement of GDP from eIF-2r X GDP. 7) eIF-2y bound [3H]GDP and this binding was significantly enhanced in the presence of Mg2+. Also, [3H]GDP in the preformed eIF-2y X [3H]GDP complex was rapidly exchanged with exogenously added unlabeled GDP in the presence of Mg2+. Co-eIF-2A20y had no effect on GDP binding to eIF-2y nor on GDP exchange reactions. 8) Reticulocyte heme-regulated protein synthesis inhibitor, which phosphorylated almost completely (in excess of 80%) the alpha-subunit (Mr 38,000) of eIF-2r, also phosphorylated similarly the smaller subunit (Mr 36,000) of eIF-2y. However, such phosphorylation had no significant effect on ternary complex formation, GDP binding, and GDP exchange reactions.

Purification and properties of eukaryotic initiation factor 2 and its ancillary protein factor (Co-eIF-2A) from yeast Saccharomyces cerevisiae

Two peptide chain initiation factor activities, eIF-2y and Co-eIF-2A20y, were purified from the high speed supernatant fraction of the yeast Saccharomyces cerevisiae and their properties were studied. 1) In sodium dodecyl sulfate-polyacrylamide gels, purified eIF-2y showed two major polypeptide bands corresponding to molecular weights of 54,000 and 36,000. The Mr 54,000 band was significantly more intense than the Mr 36,000 band, indicating the possible presence of two polypeptides of equal molecular weight in this band. The molecular weight of eIF-2y, determined using a density gradient centrifugation method, was approximately 140,000. 2) In sodium dodecyl sulfate-polyacrylamide gel, purified Co-eIF-2A20y showed a single polypeptide band corresponding to a molecular weight of 20,000. A similar molecular weight for Co-eIF-2A20y was also found using a density gradient centrifugation method. 3) In partial reactions, eIF-2y bound Met-tRNAf in the presence of Mg2+. The reaction required GTP. Co-eIF-2A20y stimulated Met-tRNAf binding to eIF-2y (2-3-fold) and also rendered the complex stable to 3 X 10(-5) M aurintricarboxylic acid. 4) This Co-eIF-2A20y activity was heat-labile and N-ethylmaleimide-insensitive. 5) Antibodies were prepared by injecting rabbits with homogeneous Co-eIF-2A20y. Such anti-Co-eIF-2A20y inhibited (60%) protein synthesis in a yeast cell-free protein synthesizing system and completely blocked Co-eIF-2A20y stimulation of Met-tRNAf. 40 S initiation complex formation. Protein synthesis inhibition by anti-Co-eIF-2A20y was almost completely reversed by preincubation of the antibodies specifically with homogeneous Co-eIF-2A20y.

Protein synthesis in rabbit reticulocytes. A study of the roles of Co-eIF-2, Co-eIF-2A80, and GDP in peptide chain initiation

The roles of Co-eIF-2, Co-eIF-2A80, and GDP in ternary complex and Met-tRNAf X 40 S initiation complex formation were studied. 1) Partially purified eukaryotic initiation factor 2 (eIF-2) (50% pure) preparations contained 0.4-0.6 pmol of bound GDP/pmol of eIF-2. eIF-2 purity was calculated from ternary complex formation in the absence of Mg2+ and in the presence of excess Co-eIF-2. 2) In the absence of Mg2+, approximately 30% of the potentially active eIF-2 molecules formed ternary complexes, and both Co-eIF-2 and Co-eIF-2A80 were equally effective in full activation of the eIF-2 molecules for ternary complex formation. 3) In the presence of Mg2+, approximately 10% of the potentially active eIF-2 molecules formed ternary complexes in the absence of ancillary factors, and the ancillary factors Co-eIF-2A80 and Co-eIF-2 raised the incorporation to 20 and 50% of the eIF-2 molecules, respectively. 4) In the absence of Mg2+, [3H]GDP in preformed eIF-2 X [3H]GDP was readily displaced by GTP during ternary complex formation. 5) In the presence of Mg2+, [3H]GDP remained tightly bound to eIF-2 and ternary complex formation was inhibited. Co-eIF-2, but not Co-eIF-2A80, was effective in promoting [3H]GDP displacement and the former was more effective in promoting ternary complex formation than the latter. 6) eIF-2 X [3H]GDP was converted to eIF-2 X [3H] GTP by incubation in the presence of nucleoside-5'-diphosphate kinase and ATP, but the eIF-2 X [3H]GTP thus formed did not bind Met-tRNAf in the presence of Mg2+ and required exogeneous addition of Co-eIF-2 and GTP for ternary complex formation and GTP displacement. 7) In the absence of Mg2+, the increased ternary complex formed in the presence of eIF-2 X [3H] GDP and Co-eIF-2A80 (with accompanying loss of [3H] GDP) was inactive in a subsequent reaction, which involves Met-tRNAf transfer to 40 S ribosomes (in the presence of Mg2+), and required trace amounts of Co-eIF-2 for such activity. Based on the above observations, we have suggested a two-step activation of eIF-2 molecules by the Co-eIF-2 protein complex for functional ternary complex formation. One of these steps involves the Co-eIF-2A component of Co-eIF-2. This activation results in stimulated Met-tRNAf binding to eIF-2 and is most apparent in the absence of Mg2+ and with aged eIF-2 molecules.(ABSTRACT TRUNCATED AT 400 WORDS)

Protein synthesis in rabbit reticulocytes: Requirements for Met-tRNAf·40S preinitiation complex formation with AUG-codon and physiological mRNAs

Under standard conditions, in the presence of GTP, highly purified eIF-2 and Co-eIF-2 factor preparations efficiently stimulated AUG-codon dependent but not physiological mRNA-dependent Met-tRNAf binding to 40S ribosomes. Replacement of GTP by a nonhydrolyzable GTP analog, GMP-PNP, in the above system, gave significant stimulation of Met-tRNAf binding to 40S ribosomes dependent on physiological mRNAs. Lower but significant stimulation of Met-tRNAf binding to 40S ribosomes was also observed when GTP was used in the presence of nucleoside 5'-diphosphate kinase (NDK) and ATP. ATP alone in the absence of NDK had no significant effect. This is the first report on the formation of a stable Met-tRNAf . 40S initiation complex dependent on physiological mRNAs and the factor requirements for such complex formation.