Cannabinoids for SARS-CoV-2 and is there evidence of their therapeutic efficacy?

To combat the coronaviruses and their novel variants, therapeutic drugs and the development of vaccines that are to be effective throughout human life are urgently needed. The endocannabinoid system (ECS) acts as a modulator in the activation of the microcirculation, immune system, and autonomic nervous system, along with controlling pharmacological functions such as emotional responses, homeostasis, motor functions, cognition, and motivation. The ECS contains endogenous cannabinoids, cannabinoid receptor (CBRs), and enzymes that regulate their biosynthesis, transport, and degradation. Moreover, phytocannabinoids and synthetic cannabinoids that mimic the action of endocannabinoids also play an essential role in the modulation of the ECS. Cannabinoids, the main constituents of cannabis (Cannabis sativa L.), are therapeutic compounds that have received international attention in the health field due to their therapeutic properties. Recently, they have been tested for the treatment of COVID-19 due to their antiviral properties. Indeed, cannabinoid-type compounds, and in particular cannabidiol (CBD), isolated from glandular trichomes found in the calyx of cannabis flowers with reported antiviral properties is hypothesized to be a therapeutic option in the ministration of SARS-CoV-2 consorted with COVID-19 disease. The relevant articles were determined from the database search published mainly in Web of Science, Google scholar, PubMed, Crossref, and ClinicalTrials.gov database during the pandemic period. The articles were evaluated for the therapeutic potentials, mechanisms of action of cannabinoids, the roles of the ECS in the immune system, impact of cannabinoids in SARS-CoV-2 septic, especially if they address the application of cannabinoids as drugs for the curability and management of SARS-CoV-2 and its novel variants. Although the evidence needed to be considered using cannabinoids in the control and treatment of viral diseases is currently in its infancy, they already offer an opportunity for clinicians due to their effects in relieving pain, improving appetite, and improving childhood epilepsy, especially in cancer and human immunodeficiency virus (HIV/AIDS) patients. In addition to these, the most recent scientific evidence emphasizes their use in the treatment of the coronavirus infected patients. In brief, all preclinic and clinic studies that have been reported show that, through the cannabinoid system, cannabinoids, particularly CBD, have many mechanisms that are effective in the treatment of patients infected by SARS-CoV-2. Thus, more extensive studies are necessary in this area to fully identify the effects of cannabinoids on SARS-CoV-2.     

Some benzoxazoles and benzimidazoles as DNA topoisomerase I and II inhibitors

Some novel fused heterocyclic compounds of 2, 5-disubstituted-benzoxazole and benzimidazole derivatives, which were previously synthesized by our group, were investigated for their inhibitory activity on both eukaryotic DNA topoisomerase I and II in a cell free system. 2-Phenoxymethylbenzimidazole (17), 5-amino-2-(p-fluorophenyl)benzoxazole (3), 5-amino-2-(p-bromophenyl)benzoxazole (5), 5-nitro-2-phenoxymethyl-benzimidazole (18), 2-(p-chlorobenzyl)benzoxazole (10) and 5-amino-2-phenylbenzoxazole (2) were found to be more potent as eukaryotic DNA topoisomerase I poisons than the reference drug camptothecin having IC(50) values of 14.1, 132.3, 134.1, 248, 443.5, and 495 microM, respectively. 5-Chloro-2-(p-methylphenyl)benzoxazole (4), 2-(p-nitrobenzyl)benzoxazole (6) and 5-nitro-2-(p-nitrobenzyl)benzoxazole (8) exhibited significant activity as eukaryotic DNA topoisomerase II inhibitors, having IC(50) values of 22.3, 17.4, 91.41 microM, respectively, showing higher potency than the reference drug etoposide.     

Comparative pollen morphology of sect. <Emphasis Type="Italic">Quinqueloculares</Emphasis> (Campanulaceae) in Turkey

The pollen morphology of Turkish species belonging to sect. Quinqueloculares (Boiss.) Phitos (Campanulaceae) were investigated with a light microscope (LM) and scanning electron microscope (SEM). All examined species are endemic, except Campanula crispa Lam. According to the results of this study, pollen grains of the examined taxa were triporate and spheroidal. Their sculpture was spinose and baculate (C. crispa Lam.); spinulose and microperforate (C. tomentosa Lam.); microperforate (C. vardariana Bocquet) or more commonly, microechinate (C. iconia Phitos, C. lyrata Lam. subsp. lyrata, C. hagielia Boiss., C. sorgerae Phitos, C. betonicifolia SM., C. karadjana Bocquet, C. telmessi Hub.-Mor. & Phitos, C. davisii Turrill).     

The effects of cadmium chloride on secondary metabolite production in Vitis vinifera cv. cell suspension cultures

Background

Plant secondary metabolites are possess several biological activities such as anti-mutagenic, anti-carcinogenic, anti-aging, etc. Cell suspension culture is one of the most effective systems to produce secondary metabolites. It is possible to increase the phenolic compounds and tocopherols by using cell suspensions. Studies on tocopherols production by cell suspension cultures are seldom and generally focused on seed oil plants. Although fresh grape, grape seed, pomace and grape seed oil had tocopherols, with our best knowledge, there is no research on tocopherol accumulation in the grape cell suspension cultures. In this study, it was aimed to determine the effects of cadmium chloride treatments on secondary metabolite production in cell suspension cultures of grapevine. Cell suspensions initiated from callus belonging to petiole tissue was used as a plant material. Cadmium chloride was applied to cell suspension cultures in different concentration (1.0 mM and 1.5 mM) to enhance secondary metabolite (total phenolics, total flavanols, total flavonols, trans-resveratrol, and α-, β-, γ- δ-tocopherols) production. Cells were harvested at two days intervals until the 6^th day of cultures. Amounts of total phenolics, total flavanols and total flavonols; trans-resveratrol and tocopherols (α-, β-, γ- and δ-tocopherols) and dry cell weights were determined in the harvested cells.

Results

Phenolic contents were significantly affected by the sampling time and cadmium concentrations. The highest values of total phenolic (168.82 mg/100 g), total flavanol (15.94 mg/100 g), total flavonol (14.73 mg/100 g) and trans-resveratrol (490.76 μg/100 g) were found in cells treated with 1.0 mM CdCl₂ and harvested at day 2. Contents of tocopherols in the cells cultured in the presence of 1.0 mM CdCl₂ gradually increased during the culture period and the highest values of α, β and γ tocopherols (145.61, 25.52 and 18.56 μg/100 g) were detected in the cell cultures collected at day 6.

Conclusions

As a conclusion, secondary metabolite contents were increased by cadmium chloride application and sampling time, while dry cell weights was reduced by cadmium chloride treatments.     

Regulation of mammalian mitochondrial translation by post-translational modifications

Mitochondria are responsible for the production of over 90% of the energy in eukaryotes through oxidative phosphorylation performed by electron transfer and ATP synthase complexes. Mitochondrial translation machinery is responsible for the synthesis of 13 essential proteins of these complexes encoded by the mitochondrial genome. Emerging data suggest that acetyl-CoA, NAD(+), and ATP are involved in regulation of this machinery through post-translational modifications of its protein components. Recent high-throughput proteomics analyses and mapping studies have provided further evidence for phosphorylation and acetylation of ribosomal proteins and translation factors. Here, we will review our current knowledge related to these modifications and their possible role(s) in the regulation of mitochondrial protein synthesis using the homology between mitochondrial and bacterial translation machineries. However, we have yet to determine the effects of phosphorylation and acetylation of translation components in mammalian mitochondrial biogenesis. This article is part of a Special Issue entitled: Mitochondrial Gene Expression.     

Can screening Chlamydia trachomatis by serological tests predict tubal damage in infertile patients?

Effectiveness of screening Chlamydia trachomatis (CT) antibody to predict tubal damage was assessed in this prospective study which was performed in a teaching hospital between September 2003 and September 2004. The study group consisted of 152 patients who underwent laparoscopy for infertility and the control group consisted of 80 fertile women who gave birth in the same hospital. CT antibody levels were measured by IFA (Indirect Fluorescence Assay for CT). Adhesions were defined by Gomel's classification system. Rate of seropositivity of CT was 34.6% in the study group and 22.5% in the control group (p>0.05). In the study group, the sensitivity, specifity, positive predictive and negative predictive values of CT positivity for tubal damage were 40%, 69.5%, 50% and 60.2% respectively. In the infertile group, the rate of tubal adhesion in the CT positive group was 50% and in the CT negative group it was 39.7% (p>0.05). However, there was a positive correlation between the severity of tubo-peritoneal adhesions and seropositivity for CT. In this study, we found out that tubo-peritoneal adhesions could not be predicted by the presence of CT inserum. There was a positive correlation between high CT seropositivity and high degree of adhesions.     

Ceruloplasmin, Copper, Selenium, Iron, Zinc, and Manganese Levels in Normal and Sulfite Oxidase Deficient Rat Plasma: Effects of Sulfite Exposure

A noticeable effect of sulfite treatment was observed on the plasma ceruloplasmin ferroxidase activity of rats with normal sulfite oxidase activity when compared to normal controls. The plasma levels of selenium, iron, and zinc were unaffected by sulfite in normal and sulfite oxidase (SOX)-deficient rats. While plasma level of Mn was decreasing, plasma Cu level increased in SOX-deficient rats. Treating SOX-deficient groups with sulfite did not alter plasma level of Mn but made plasma level of Cu back to its normal level. This is the first evidence that Cu and Mn status were affected in experimental sulfite oxidase deficiency induced by low molybdenum diet with tungsten addition deserving further research to determine the underlying mechanisms of these observations in experimental sulfite oxidase deficiency.     

Investigation of the association between ATP2B4 and ATP5B genes with colorectal cancer

Colorectal cancer (CRC) develops as a multi-step process which results from gradual accumulation of mutations in proto-oncogenes, tumor suppressor, and DNA repair genes. Mortality rate of CRC is very high. Therefore, development of alternative diagnostic methods which can be used in the early diagnosis is crucial. ATP2B4 gene encodes one of the four isoforms of p-type ATPase PMCA enzyme and bears critical importance in maintaining the balance of intracellular calcium homeostasis by providing the export of calcium ions out of the cell. ATP5B encodes a subunit of the mitochondrial ATP synthase which is an f-type ATPase. In this study, the relationship between ATP2B4 and ATP5B genes and CRC regarding gene expression was investigated. Study groups were constructed from a number of 50 patients (25 males, 25 females) with the mean age of 55.68 ± 9.4 and the gene expression levels in the healthy and cancerous tissues of the patients were compared by using semi-quantitative PCR and Real-Time PCR methods. As a result, in patients with rectum tumors, there was a significant relationship between ATP2B4 gene expression and the tumor location and in patients younger than 45 years, ATP5B gene expressions were detected significantly higher in tumor tissues by using RT-PCR. However, no significant relationship was detected in terms of expression differences of ATP2B4 and ATP5B genes between cancerous and healthy tissues of the CRC patients. ATP2B4 and ATP5B genes might have indirect associations in CRC pathogenesis and the investigation of their interactions with DNA repair and other related genes may help in understanding of CRC formation.     

Carbon Supply and Photoacclimation Cross Talk in the Green Alga Chlamydomonas reinhardtii

Photosynthetic organisms are exposed to drastic changes in light conditions, which can affect their photosynthetic efficiency and induce photodamage. To face these changes, they have developed a series of acclimation mechanisms. In this work, we have studied the acclimation strategies of Chlamydomonas reinhardtii, a model green alga that can grow using various carbon sources and is thus an excellent system in which to study photosynthesis. Like other photosynthetic algae, it has evolved inducible mechanisms to adapt to conditions where carbon supply is limiting. We have analyzed how the carbon availability influences the composition and organization of the photosynthetic apparatus and the capacity of the cells to acclimate to different light conditions. Using electron microscopy, biochemical, and fluorescence measurements, we show that differences in CO₂ availability not only have a strong effect on the induction of the carbon-concentrating mechanisms but also change the acclimation strategy of the cells to light. For example, while cells in limiting CO₂ maintain a large antenna even in high light and switch on energy-dissipative mechanisms, cells in high CO₂ reduce the amount of pigments per cell and the antenna size. Our results show the high plasticity of the photosynthetic apparatus of C. reinhardtii. This alga is able to use various photoacclimation strategies, and the choice of which to activate strongly depends on the carbon availability.Light sustains virtually all life on Earth through the process of photosynthesis. However, light can be very harmful for oxygenic photosynthetic organisms, as excess absorption can lead to the production of reactive oxygen species. In order to survive and grow, these organisms have developed various photoacclimation mechanisms operating on different time scales that protect the cell from photodamage. In the green alga Chlamydomonas reinhardtii, these mechanisms vary from negative phototaxis and multicomponent nonphotochemical quenching (NPQ) to a number of physiological and biochemical changes (Erickson et al., 2015). C. reinhardtii cells are around 10 μm in diameter, and a large part of their total volume is occupied by a single horseshoe-shaped chloroplast (Sager and Palade, 1957). The photosynthetic machinery responsible for the light reactions is located in thylakoid membranes and contains four major components: PSII, cytochrome b₆f, PSI, and ATP synthase. Both photosystems bind chlorophyll (Chl) and carotenoid (Car) and are composed of a core and several outer antennae pigment-protein complexes, the main function of which is light harvesting and its conversion into chemical energy. The PSII core is composed of D1, D2, CP43, and CP47 pigment-protein complexes and several smaller subunits, the number of which varies between organisms (Shi et al., 2012). The outer antenna contains the light-harvesting complex II (LHCII), which in C. reinhardtii is encoded by nine LHCBM genes, and the minor antennae CP26 and CP29 (Nield et al., 2000; Teramoto et al., 2001; Natali and Croce, 2015). These complexes are assembled together to form PSII-LHCII supercomplexes (Tokutsu et al., 2012; Drop et al., 2014). The PSI core is composed of a PSAA-PSAB heterodimer and a number of smaller subunits (Jensen et al., 2007), and in C. reinhardtii the LHCI antenna consists of nine LHCA proteins (Mozzo et al., 2010) that are associated with the core to form the PSI-LHCI complex (Stauber et al., 2009; Drop et al., 2011).The composition and organization of the thylakoid membrane is light dependent. The gene expression of different LHCs has been reported to be affected by light acclimation (Teramoto et al., 2002; Durnford et al., 2003; Yamano et al., 2008) and to be NAB1 regulated (Mussgnug et al., 2005). It has been observed that long-term high-light exposure of C. reinhardtii cells leads to a 50% decrease of Chl content (Neale and Melis, 1986; Bonente et al., 2012) and to changes in Chl-to-Car ratio (Niyogi et al., 1997a; Baroli et al., 2003; Bonente et al., 2012), suggesting reduction of the antenna size (Neale and Melis, 1986), although, in a more recent report (Bonente et al., 2012), it was concluded that the antenna size is not modulated by light in this alga. Recently, a dependence of the antenna components on the carbon availability also was reported. It was shown that, when cells grown in acetate are shifted from high to low CO₂ concentration, the functional antenna size of PSII decreases and a down-regulation of LHCBM6/8 occurs (Berger et al., 2014).In the short term, the main response to high light is the dissipation of energy absorbed in excess heat in a process called qE, or energy-dependent quenching, which is the fastest component of NPQ. In land plants, the main player in this process is the protein PsbS (Li et al., 2002, 2004), while in C. reinhardtii, the process is centered around LHCSR1 and LHCSR3 (Peers et al., 2009; Dinc et al., 2016). LHCSR3, the most studied of the two, is a pigment-protein complex that is expressed within 1 h of high-light exposure (Allorent et al., 2013) in combination with CO₂ limitation (Yamano et al., 2008; Maruyama et al., 2014). The qE onset is triggered by lumen acidification sensed by LHCSR3/1 (Bonente et al., 2011; Liguori et al., 2013; Tokutsu and Minagawa, 2013; Dinc et al., 2016).Cars are well known to be involved in photoprotection. They quench triplet Chl and scavenge singlet oxygen (¹O₂; Frank and Cogdell, 1996). In C. reinhardtii, the antioxidant role of xanthophylls is well illustrated by the mutant npq1 lor1 lacking lutein and zeaxanthin (Niyogi et al., 1997b). This mutant is deficient in qE, but compared with other qE-deficient mutants like npq4 (Peers et al., 2009) and npq5 (Elrad et al., 2002), which are LHCSR3 and LHCBM1 knockouts, respectively, it is extremely light sensitive, due to the absence of quenching of triplet Chl and ¹O₂ by zeaxanthin and lutein.Aquatic oxygenic photosynthetic organisms meet several challenges in CO₂ fixation (Moroney and Ynalvez, 2007). First, the diffusion of CO₂ in water is 10,000 times slower than in air. Second, the CO₂-fixing enzyme Rubisco is not selective for CO₂ and also binds oxygen, resulting in the process of photorespiration. Third, the form of inorganic carbon depends on the pH (i.e. in alkaline pH, it is HCO₃⁻, while in acidic pH, it is CO₂; Beardall, 1981; Gehl et al., 1987). This diminishes even further the availability of CO₂ in the cell. In order to overcome these CO₂ fixation barriers, algae have developed carbon-concentrating mechanisms (CCMs; Moroney and Ynalvez, 2007). The essence of these processes lies in the active pumping of inorganic carbon in the cell via a number of transporters that concentrate it in the pyrenoid, a ball-like structure containing Rubisco, Rubisco activase, and intrapyrenoid thylakoids and surrounded by a starch sheath. In the pyrenoid, HCO₃⁻ is converted to CO₂ by CARBONIC ANHYDRASE3 (CAH3; Blanco-Rivero et al., 2012; Sinetova et al., 2012) and then fixed by Rubisco in the Calvin-Benson-Bassham cycle. CAH3 also is suggested to provide HCO₃⁻ in the proximity of the oxygen-evolving complex, where it may function as a proton carrier, removing H⁺ from water splitting to avoid photoinhibition (Villarejo et al., 2002; Shutova et al., 2008).C. reinhardtii also can grow mixotrophically using alternative organic carbon sources present in its environment. For example, it can take up acetate, which is then incorporated into the citric cycle, producing reducing equivalents and CO₂ (Johnson and Alric, 2012), and into the glyoxylate cycle, producing malate (Lauersen et al., 2016). In the presence of acetate, it has been reported that CO₂ uptake and oxygen evolution were decreased by half under saturating CO₂ and light intensities without affecting PSII efficiency, respiration, and cell growth (Heifetz et al., 2000). In addition, reactions of the oxidative pentose phosphate and glycolysis pathways, inactive under phototrophic conditions, show substantial flux under mixotrophic conditions (Chapman et al., 2015). Furthermore, acetate can replace PSII-associated HCO₃⁻, reducing ¹O₂ formation and, therefore, acting as a photoprotector during high-light acclimation (Roach et al., 2013).In short, high-light acclimation is a complex, multicomponent process that happens on different time scales. Furthermore, it is embedded in the overall metabolic network and is potentially influenced by different nutrients and metabolic states. A thorough understanding of this process and its regulation is crucial for fundamental research and applications. To determine if different carbon supply conditions trigger different light acclimation strategies and photoprotective responses, we systematically studied C. reinhardtii cells grown in mixotrophic, photoautotrophic, and high-CO₂ photoautotrophic conditions in different light intensities.We show that C. reinhardtii cells use different strategies to acclimate to high light depending on the carbon availability and trophic status. These results underline the strong connection between metabolism and light acclimation responses and reconcile the data from various reports. Furthermore, our study demonstrates how, in a dynamic system such as C. reinhardtii, a single change in growth conditions has large effects at multiple levels.