Insect multimeric G-quadruplexes fold into antiparallel structures of different compactness and stability in K+ and Na+ solutions.

Human telomere sequences (TTAGGG)n fold into G-quadruplexes with different conformations in K+ and Na+ solutions, which are highlighted for their potential as antitumor drug targets. Moreover, human multimeric G-quadruplexes have been broadly studied potentially for screening ligands with higher selectivity than monomeric G-quadruplexes. Most insects have telomeres consisting of pentanucleotide (TTAGG) repeats, which fold into an antiparallel structured G-quadruplex with a two-layer G-planar in a K+ solution. However, the structure of insect telomeric G-quadruplexes in Na+ solutions and their higher-order structures have not been explored. The quinoline derivative BMPQ-1 has been reported to bind human multimeric G-quadruplex. This study compared the stability and compactness of insect monomeric and multimeric G-quadruplex structures in K+ and Na+ solutions and further validated the interaction between BMPQ-1 and insect multimeric G-quadruplexes. Circular dichroism (CD) spectral scanning analysis revealed that although the insect telomeric G-quadruplex folds into an antiparallel structure in both K+ and Na+ solutions, all the insect telomeric G-quadruplexes are more stable in Na+ solutions. Fluorescence resonance energy transfer (FRET) analysis indicated insect telomeric G-quadruplexes have a more compact structure in Na+ solutions. BMPQ-1 exhibited higher selectivity for insect multimeric G-quadruplex Bom37 than monomeric G-quadruplex Bom17, and had a different binding pattern to Bom37 G-quadruplex in K+ and Na+ solutions. Finally, BMPQ-1 was found to have a significant inhibitory effect on the proliferation of pest cells. This study contributes to our comprehensive understanding of insect telomeric G-quadruplexes.

Mycoviruses: Antagonistic Potential, Fungal Pathogenesis, and Their Interaction with Rhizoctonia solani.

Mycoviruses, or fungal viruses, are prevalent in all significant fungal kingdoms and genera. These low-virulence viruses can be used as biocontrol agents to manage fungal diseases. These viruses are divided into 19 officially recognized families and 1 unclassified genus. Mycoviruses alter sexual reproduction, pigmentation, and development. Spores and fungal hypha spread mycoviruses. Isometric particles mostly encapsulate dsRNA mycoviruses. The widespread plant-pathogenic fungus Rhizoctonia solani, which has caused a rice sheath blight, has hosted many viruses with different morphologies. It causes significant crop diseases that adversely affect agriculture and the economy. Rice sheath blight threatens the 40% of the global population that relies on rice for food and nutrition. This article reviews mycovirology research on Rhizoctonia solani to demonstrate scientific advances. Mycoviruses control rice sheath blight. Hypovirulence-associated mycoviruses are needed to control R. solani since no cultivars are resistant. Mycoviruses are usually cryptic, but they can benefit the host fungus. Phytopathologists may use hypovirulent viruses as biological control agents. New tools are being developed based on host genome studies to overcome the intellectual challenge of comprehending the interactions between viruses and fungi and the practical challenge of influencing these interactions to develop biocontrol agents against significant plant pathogens.

Effects of Molecular Crowding on the Structure, Stability, and Interaction with Ligands of G-quadruplexes.

G-quadruplexes (G4s) are widely found in cells and have significant biological functions, which makes them a target for screening antitumor and antiviral drugs. Most of the previous research on G4s has been conducted mainly in diluted solutions. However, cells are filled with organelles and many biomolecules, resulting in a constant state of a crowded molecular environment. The conformation and stability of some G4s were found to change significantly in the molecularly crowded environment, and interactions with ligands were disturbed to some extent. The structure of the G4s and their biological functions are correlated, and the effect of the molecularly crowded environment on G4 conformational transitions and interactions with ligands should be considered in drug design targeting G4s. This review discusses the changes in the conformation and stability of G4s in a physiological environment. Moreover, the mechanism of action of the molecularly crowded environment affecting the G4 has been further reviewed based on previous studies. Furthermore, current challenges and future research directions are put forward. This review has implications for the design of drugs targeting G4s.

Molecular crowding promotes the aggregation of parallel structured G-quadruplexes.

G-quadruplexes are widely distributed in cells and are usually essential in mediating biological processes. The intracellular environment is often in a state of molecular crowding, and the current research considerably focuses on the effect of molecular crowding on the conformation of telomeric G-quadruplexes. However, G-quadruplex-forming oligonucleotides are primarily located in the promoter region of the proto-oncogene and on mRNA inside the cell and are reported to fold into parallel structures. Thus, studying the interaction mechanism between ligands and parallel structured G-quadruplexes under crowding conditions is crucial for the design of drugs targeting G-quadruplexes. In our study, molecular crowding was simulated through polyethylene glycol with an average molecular weight of 200 (PEG200) to investigate the parallel structure of the canonical G-quadruplexes c-KIT1, c-MYC, and 32KRAS and their interactions with ligands. Circular dichroism (CD) spectral scanning, fluorescence resonance energy transfer (FRET), and native polyacrylamide gel electrophoresis (PAGE) analysis revealed that molecular crowding failed to induce oligonucleotides to form parallel G-quadruplex structures in the explored model sequences while induced telomeric G-rich sequences to form antiparallel G-quadruplexes in solution without K+. Molecular crowding did not induce changes in their parallel structures but promoted the formation of G-quadruplex aggregates. Moreover, to some extent, molecular crowding also induced a looser structure of the monomer G-quadruplexes. Further studies showed that molecular crowding did not alter the binding stoichiometry of the ligand 3,11-difluoro-6,8,13-trimethyl-8H-quino [4,3,2-kl] acridinium methosulfate (RHPS4) to c-KIT1, while it inhibited its interaction with parallel structured G-quadruplexes. This work provides new insights into developing anticancer drugs targeting parallel structured G-quadruplexes.

RHPS4 shifted the conformation ensemble equilibrium of Tel24 by preferentially stabilizing the (3 + 1) hybrid-2 conformation.

Telomeric G-quadruplexes have been a promising target for developing antitumor drugs with fewer side effects. The intracellular environment is usually in a state of molecular crowding. Studying the interaction mechanism among ligands and telomeric G-quadruplexes under crowded conditions is important for designing drugs that target telomeric G-quadruplexes. In the present study, the telomeric G-quadruplex Tel24 (TTAGGG)4 was found to fold into a conformational ensemble of parallel and (3 + 1) hybrid-2 conformations in solution with molecular crowding conditions created by PEG200. G-quadruplex-ligand 3,11-difluoro-6,8,13-trimethyl-8H-quino[4,3,2-kl] acridinium methosulfate (RHPS4) preferentially stabilized the (3 + 1) hybrid-2 conformation and shifted the conformational ensemble equilibrium of Tel24 towards the hybrid conformation. We also found that the (3 + 1) hybrid-2 conformation of Tel24 was more likely to form as compared to the parallel conformation in the conformational ensemble of Tel24. Overall, this study provides new insights into the conformation of telomere G-quadruplexes and their interactions with ligands in a physiological environment.

In vitro administration of sodium arsenite in mouse prepubertal testis induces germ cell loss and apoptosis.

High levels of arsenic contamination in drinking water pose serious health risks in numerous countries. The documentation reporting arsenic toxicity on reproduction and development is increasing, with evidence of arsenic inducing fertility and developmental issues. Nonetheless, the impact of arsenic exposure on the development of the male reproductive system is not fully elucidated. In the present study, we have investigated the direct effects of arsenic on prepubertal mouse testis using an in vitro testicular organ culture system. Culture medium was supplemented with a range of concentrations of sodium arsenite, examining effects of low (0.5 and 1 µM) and high (10, 50, 100 µM) concentrations, in cultures of post-natal day 5 CD1 mouse testis. In vitro exposure of low arsenic concentrations (0.5 or 1 µM) for 6 days did not cause any change in the testicular morphology, germ cells density, or apoptotic marker cleaved caspase 3 (CC3) expression. In contrast, exposure of prepubertal testis to high arsenic concentrations (10, 50 or 100 µM) induced drastic changes: severe destruction of testicular morphology, with loss of seminiferous tubule integrity; a dose-dependent decrease in germ cell density, and a hundred-fold increase in CC3 expression after 50 µM arsenic exposure. In conclusion, high arsenic treatment induced a dose-dependent induction of apoptosis and germ cell loss in prepubertal mouse testis.

In vitro application of sodium arsenite to mice testicular and epididymal organ cultures induces oxidative, biochemical, hormonal, and genotoxic stress.

Arsenic poisoning is well-known for its innumerable toxic and carcinogenic effects. In vivo data on reproductive toxicity are also known but in vitro data are scant. Presently, we evaluated the in vitro toxic effects of sodium arsenite (NaAsO2) on adult mice testes and epididymal tissues using organ cultures. Testicular and epididymal fragments were incubated at 37°C and 33°C, respectively, with 1, 10, 50, and 100 µM concentrations of NaAsO2. Cultures were allowed to incubate for 2 and 24 h. Levels of oxidative stress markers, the reactive oxygen species (ROS) and thiobarbituric acid reactive substance assay (TBARS), antioxidant enzymes, testosterone concentrations, and the extent of sperm DNA damage, were estimated. Results were analyzed statistically at p < 0.05. Results demonstrated both time- and dose-dependent alterations whereby, following 24-h incubation with NaAsO2, substantial increases were noticeable in ROS and TBARS levels and sperm DNA damage (p < 0.001), while decreases (p < 0.001) occurred in catalase, peroxidase, and superoxide dismutase levels at 10, 50, and 100 µM concentrations. Incubations for 2 h revealed similar but relatively less toxic effects. Testosterone concentrations decreased significantly only after 24 h of incubation with 50 (1.95 vs. 2.93 ng g-1; p < 0.01) and 100 µM (1.32 vs. 2.93 ng g-1; p < 0.001) NaAsO2 concentrations. The study concluded that exposure of testicular and epididymal tissue fragments to arsenic under in vitro conditions induces rapid and immediate metabolic and genotoxic damage at higher concentrations.

Chemical crowd control agents.

Chemical crowd control agents are also referred to as riot control agents and are mainly used by civil authorities and government agencies to curtail civil disobedience gatherings or processions by large crowds. Common riot control agents used to disperse large numbers of individuals into smaller, less destructive, and more easily controllable numbers include chloroacetophenone, chlorobenzylidenemalononitrile, dibenzoxazepine, diphenylaminearsine, and oleoresin capsicum. In this paper, we discuss the emergency medical care needed by sufferers of acute chemical agent contamination and raise important issues concerning toxicology, safety and health.

ABO blood group frequency in Ischemic heart disease patients in Pakistani population.

OBJECTIVES: To determine if there is any significant association between ABO blood groups and ischemic heart disease (IHD). METHODS: The study was performed at Punjab Institute of Cardiology (PIC), Lahore. Study duration was from January 2012 to September 2012. This study included 200 IHD patients and 230 control individuals. Self design questionnaire was used to collect information regarding risk factors. Standard agglutination test was performed to determine the blood groups. Data was analyzed on SPSS 16. RESULTS: The prevalence of blood groups in IHD group was 34% in blood group A, 29% in blood group B, 14% in blood group AB and 23% in blood group O. In control group the distribution of B, A, AB and O blood groups were 34.4%, 20.9%, 12.6%, 32.2% respectively. Rh+ve factor was prevalent in 90.5% among IHD group and 92.6% in control subjects. The prevalence of IHD was more in males (63.5%) as compared to females (36.5%). Mean age was 56.4±0.86 (yrs) and BMI was 26.4±0.33 (kg/m(2)). The prevalence of hypertension was 58.5%, diabetes was 53%, family history of cardiac disease was 45%, 35.5% of patients were doing exercise regularly, 58.5% used ghee, and 58% were smokers. C onclusion: Subjects with blood group A had significantly (p< 0.05) higher risk of developing IHD as compare to other blood groups.

Clinical profile and complication of malaria hepatopathy.

BACKGROUND: This study was designed to study the patient characteristics, presenting features and complications of malaria in patients with elevated liver enzymes and to compare these data to those of patients with normal liver enzymes. METHODS: A convenient sample of 100 patients with malaria was selected from three tertiary care referral hospitals. Study subjects were divided into two groups: (1) patients (controls) with normal liver enzymes and (2) patients (cases) with >3 times the normal liver enzymes in the absence of an alternate explanation for such elevation. Patient characteristics, presenting features and complications of malaria in these two groups were studied. Data were collected using a semi-structured pretested proforma and were analyzed using the statistical analysis program SPSS, version 11.5 (SPSS, Inc., Chicago, IL). RESULTS: The mean ages were 38.12 years for the cases and 35.20 years for the controls with a non-significant p value of 0.289. Males composed 82% of the cases that were diagnosed with malarial hepatopathy; the remaining 18% were females. Falciparum malaria was present in 56% of the cases, compared to 12% of the controls. Icterus was present in 66% of cases of malarial hepatopathy, compared to 32% of the controls. Of the 66% of these cases, 18.18% had serum bilirubin >3mg%, whereas out of the 32% of the controls presenting with icterus, only 5.55% had serum bilirubin >3mg% (p=0.003). Of the cases with malarial hepatopathy, 38% suffered from hypoglycemia, compared to 0% of the controls (p<0.001); 84% of the cases presented with thrombocytopenia, compared to 70% of the controls (p<0.001); 12% of the cases suffered from renal failure with serum creatinine levels >2mg%, compared to 2% of the controls (p=0.060). CONCLUSION: Plasmodium falciparum infection (either alone or along with P. vivax) is the leading cause of malarial hepatopathy. Jaundice is a common clinical manifestation among these patients. Patients with malarial hepatopathy have increased incidences of hypoglycemia and thrombocytopenia. Malarial hepatopathy occurs in relation to severe infection, most of which are treated with parenteral artesunate.

Gas geyser--a cause of fatal domestic carbon monoxide poisoning.

Carbon monoxide is responsible for a large number of accidental domestic poisoning and deaths throughout the world. Domestic carbon monoxide poisoning is rarely reported in India and remains an under recognized problem. The diagnosis of carbon monoxide poisoning is usually based on autopsy findings, circumstantial evidence and estimation of carboxy-haemoglobin in blood. We report a case of fatal accidental carbon monoxide poisoning in a bathroom where an LPG gas water heater was installed recently. Cherry pink discolouration of the body and organs on autopsy suggested carbon monoxide poisoning. Laboratory analysis of blood by UV visible spectrophotometry revealed presence of dangerous levels of carboxy-haemoglobin. Effective preventive measures can help in bringing down the mortality and morbidity associated with carbon monoxide poisoning.