Using an aryl phenanthroimidazole moiety as a conjugated flexible intercalator to improve the hybridization efficiency of a triplex-forming oligonucleotide

When inserting 2-phenyl or 2-naphth-1-yl-phenanthroimidazole intercalators (X and Y, respectively) as bulges into triplex-forming oligonucleotides, both intercalators show extraordinary high thermal stability of the corresponding Hoogsteen-type triplexes and Hoogsteen-type parallel duplexes with high discrimination to Hoogsteen mismatches. Molecular modeling shows that the phenyl or the naphthyl ring stacks with the nucleobases in the TFO, while the phenanthroimidazol moiety stacks with the base pairs of the dsDNA. DNA-strands containing the intercalator X show higher thermal triplex stability than DNA-strands containing the intercalator Y. The difference can be explained by a lower degree of planarity of the intercalator in the case of naphthyl. It was also observed that triplex stability was considerably reduced when the intercalators X or Y was replaced by 2-(naphthlen-1-yl)imidazole. This confirms intercalation as the important factor for triplex stabilization and it rules out an alternative complexation of protonated imidazole with two phosphate groups. The intercalating nucleic acid monomers X and Y were obtained via a condensation reaction of 9,10-phenanthrenequinone (4) with (S)-4-(2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethoxy)benzaldehyde (3a) or (S)-4-(2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethoxy)-1-naphthaldehyde (3b), respectively, in the presence of acetic acid and ammonium acetate. The required monomers for DNA synthesis using amidite chemistry were obtained by standard deprotection of the hydroxy groups followed by 4,4'-dimethoxytritylation and phosphitylation.     

Error-prone PCR mutagenesis and reverse bacterial two-hybrid screening identify a mutation in asparagine 53 of the <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> ESAT6-like component EsxB that perturbs interaction with EsxD

The ESAT6-like Secretion System (ESS) of the human pathogen Staphylococcus aureus secretes heterodimeric virulence effectors such as EsxB and EsxD. To gain insights into the nature of EsxB-EsxD interaction, randomly mutated esxB generated by error-prone PCR was co-transformed together with esxD as adenylate cyclase fusion constructs into cyclase-deficient Escherichia coli, followed by reverse bacterial two-hybrid screening. Three color species were observed: dark blue, light blue, and white (no EsxB-EsxD interaction). The esxB from white colonies was subjected to standard PCR to check for gene signal, followed by SDS-PAGE for variant stability assessment. The gene coding for a stable EsxB variant that perturbed interaction with EsxD was further subjected to DNA sequencing. A single point mutation in esxB at position 157 was identified, leading to an amino acid change from asparagine to aspartic acid at position 53 in the resulting protein. Structural modeling of EsxB reveals that N53 is surface exposed. Whereas N53S substitution by site-directed mutagenesis retained heterodimerization with EsxD, N53A substitution abrogated such interaction. In addition, N53D change in EsxB did not alter interaction with EssG, another soluble component of the ESS pathway, suggesting minimal impact of the N53D substitution on EsxB stability and solubility. Taken together, these data provide new insights into the nature of EsxB-EsxD interaction and offer a systematic approach for in vivo analysis of protein-protein interactions of pathogenic bacteria in non-pathogenic hosts.     

<Emphasis Type="Italic">Trans</Emphasis>-cinnamaldehyde Modulates Hippocampal Nrf2 Factor and Inhibits Amyloid Beta Aggregation in LPS-Induced Neuroinflammation Mouse Model

Trans-cinnamaldehyde (CNM) has recently drawn attention due to its potent anti-inflammatory and antioxidant properties. The current study explored the memory enhancing effects of CNM against lipopolysaccharide (LPS)-induced neuroinflammation in mice. CNM and curcumin (a reference antioxidant) were administered at a dose of 50 mg/kg i.p. 3 h after a single LPS injection (0.8 mg/kg, i.p.) and continued daily for 7 days. Our results displayed that CNM and curcumin significantly ameliorated the LPS-induced impairment of learning and memory, neuroinflammation, oxidative stress and neuronal apoptosis. Memory functions and locomotor activity were assessed by Morris water maze, object recognition test and open field test. Both CNM and curcumin activated the nuclear factor erythroid 2 related factor 2 (Nrf2) and restored levels of downstream antioxidant enzymes superoxide dismutase and glutathione-S-transferase (GST) in the hippocampus. They also attenuated LPS-induced increase in hippocampal contents of interleukin-1β (IL-1β), malondialdehyde and caspase-3. Immunohistochemistry results showed that both CNM and curcumin reduced Aβ_1–42 protein accumulation in brain of mice. Remarkably CNM’s effect on IL-1β was less pronounced than curcumin; however it showed higher GST activity and more potent anti-apoptotic and anti-amylodogenic effect. We conclude that, CNM produces its memory enhancing effects through modulation of Nrf2 antioxidant defense in hippocampus, inhibition of neuroinflammation, apoptosis and amyloid protein burden.     

Study on the influence of caffeic acid against sodium valproate–induced nephrotoxicity in rats

Renal injury is a hallmark adverse reaction to sodium valproate (SVP), and caffeic acid (CAFF) is a phenolic compound that has anti‐inflammatory and antioxsidant properties. So, this investigation was assessed to evaluate the nephrotoxic potential of SVP and the defensive impact of CAFF against SVP nephrotoxicity. SVP was given at a dose of 500 mg/kg (i.p.) once daily for 2 weeks, while CAFF was given at a dose of 50 mg/kg (orally), simultaneously with SVP. Concurrent treatment with CAFF reduced urea and creatinine, lipid peroxidation (malondialdehyde), tumor necrosis factor alpha (TNF‐α), interferon gamma (IFN‐γ), nuclear factor kappa B (NF‐κB/p65), and transforming growth factor β (TGF‐β) levels. However, with increased glutathione content, CAFF also halted the activated Notch signaling cascade. Furthermore, CAFF suppressed caspase‐3 and inducible nitric oxide synthase expressions. To conclude, on the basis of the results obtained, CAFF proved to protect against SVP‐induced nephrotoxicity via its antioxidant, anti‐inflammatory, and antiapoptotic properties.     

Modulatory effects of some natural products on hepatotoxicity induced by combination of sodium valproate and paracetamol in rats

Possible hepatoprotective effect of Curcuma longa and/or Nigella sativa against hepatotoxicity induced by coadministration of sodium valproate (SV) and paracetamol was studied. Rats were divided into 10 groups, control groups 1, 2, 3, and 4 received vehicles, C. longa (200 mg/kg, p.o.), N. sativa (250 mg/kg, p.o.), or both herbs for 21 days, respectively. Toxicity groups 5, 6, and 7 received SV (300 mg/kg, i.p.), paracetamol (1000 mg/kg, p.o.) for the last 4 days or both for 21 days, respectively. Protection groups 8, 9, and 10 received C. longa, N. sativa, or both, respectively, 1 h before the administration of both the drugs for 21 days. SV and/or paracetamol significantly increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, relative liver/body weight ratio, malondialdehyde (MDA), tumor necrosis factor alpha (TNF‐α), and caspase‐3 (Casp‐3) while significantly decreased albumin, total protein, glutathione (GSH) reduced, GSH peroxidase, and superoxide dismutase (SOD). Preadministration of C. longa and/or N. sativa caused protective effect against the hepatotoxicity induced by both drugs.     

Plasma stearoyl‐CoA desaturase indices: Association with lifestyle,diet, and body composition

Objective:

Stearoyl‐coenzyme A desaturase‐1 (SCD1) is a key enzyme in fatty acid and energy metabolism. Increased hepatic SCD1 activity is associated with obesity and obesity‐related diseases. We examined the relations of two plasma SCD activity indices (16:1n‐7/16:0, 18:1n‐9/18:0) with body composition, and the association of lifestyle and dietary variables with the plasma SCD indices.

Design and Methods:

This population‐based, cross‐sectional study of 2021 elderly (71–74 y) men and women from the Hordaland Health Study in Western Norway was conducted using a validated food frequency questionnaire, body composition measurements by dual‐energy X‐ray absorptiometry and determination of the plasma fatty acid profile.

Results:

In multivariate regression analyses, plasma SCD indices were positively associated with BMI and body fat (P < 0.001 for both). From the 2.5th to 97.5th percentiles of plasma SCD‐16 and SCD‐18 indices, fat mass differed by about 8 kg and 5 kg, respectively. Intake of polyunsaturated fatty acids were negatively associated with SCD‐16 (partial r = ?0.30) and SCD‐18 (partial r = ?0.24) (P < 0.001 for both). Alcohol intake was positively associated with SCD‐16 (partial r = 0.26) and SCD‐18 (partial r = 0.16) (P < 0.001 for both), whereas coffee consumption and physical activity were inversely associated with SCD‐16 (P = 0.026 and P = 0.006, respectively) and SCD‐18 (P = 0.001 and P = 0.022, respectively).

Conclusions:

In this elderly population, plasma markers of SCD1 activity are associated with increased adiposity. Furthermore, modifiable dietary habits and lifestyle are associated with plasma SCD indices. These results suggest that SCD1 activity may be a promising target for weight control.

     

Ellagic Acid Antiinflammatory and Antiapoptotic Potential Mediate Renoprotection in Cisplatin Nephrotoxic Rats

Ellagic acid (EA) renoprotective effect against cisplatin (CIS)‐induced nephrotoxicity remains elusive. Therefore, male Sprague–Dawley rats received CIS alone or EA (10 and 30 mg/kg, p.o.) for 5 days before and after CIS injection. CIS increased serum levels of blood urea nitrogen, creatinine, γ‐glutamyl transferase, and reduced those of albumin and total protein. It also raised serum endothelin‐1, as well as serum and renal nitric oxide, tumor necrosis factor‐α, and monocyte chemoattractant protein‐1. CIS enhanced the renal caspase‐3, hemeoxygenase (HO)‐1, nuclear factor‐κB, and inducible nitric oxide. EA hampered CIS‐induced nephrotoxicity manifested by an enhancement of the glomerular filtration rate which was associated by the reduction of inflammatory mediators and the apoptotic marker in the serum and/or kidney. The present study discloses that EA suppresses HO‐1 and, its renoprotection is also linked to its anti‐inflammatory and antiapoptotic properties, as well as the reduction of nitric oxide and endothelin‐1.     

Life history traits of Blaptostethus pallescens (Hemiptera: Anthocoridae), a candidate for use in augmentative biological control in Egypt

Blaptostethus pallescens Poppius (Hemiptera: Anthocoridae) is an abundant native predator in mango orchards and other cropping systems in Egypt. To determine suitable mass-rearing conditions for this little-studied species, we assessed some of its biological characteristics. Testing its thermal response at three constant temperatures (20, 25, 30 °C), showed that immature development time and adult longevity decreased with increasing temperature. Reproductive success of individual females was greatest when reared at 25 °C (84.3 ± 3.1 eggs) rather than at 20 °C (46.6 ± 2.0 eggs) or 30 °C (65.2 ± 2.5 eggs). Although B. pallescens reared at 25 °C had a significantly higher net reproductive rate (R ₀), which may be attributed to their relatively rapid development and high fecundity, we argue that 30 °C seems to be more convenient for rearing B. pallescens, as mean generation time (T) and doubling time (DT) are clearly shorter, thus more individuals could be reared per unit of time at 30 °C. Mating significantly reduced male and female longevity, as unmated adults lived 25–45 % longer than mated individuals did. Unmated females did not lay eggs, suggesting that mating is a prerequisite for egg maturation. Adult males and females performed best, in terms of longevity, when fed Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) eggs instead of non-prey diets. However, diets of plant sap or pollen could sustain adults in times of limited egg availability. Because its biology is similar to that of other subtropical anthocorids already reared for augmentative releases, B. pallescens may be amenable to mass-rearing using already established techniques. Therefore, B. pallescens could be used to improve augmentative biological control in crops such as mango or maize in Egypt where it already naturally occurs, and therefore would not engender concerns over non-target effects that an exotic, generalist biological control agent would.     

Effects of Palpita unionalis and Galleria mellonella larval densities on functional response,egg dispersion and progeny sex ratio of Habrobracon hebetor

To assess the potential of the hymenopteran ectoparasitoid, Habrobracon hebetor Say as a biological control agent, we evaluated its response to different larval densities of two pyralid hosts, Palpita unionalis Hbn. and Galleria mellonella L. The former host is a serious pest of olive trees, whereas the latter is used as a factitious host in parasitoid mass rearing. In order to study the functional response of the parasitoid, five host densities (1, 2, 3, 5, 7) of either late instar larva per Petri dish were used. The shape of the functional response curve was determined using logistic regression and could be described as a type II response for both hosts, characterised by a monotonic decelerating increase in the number of hosts attacked with increasing host density. Female parasitoids allocated more eggs to the first larva attacked than all the remaining larvae. Aggregated dispersion patterns for parasitoid egg distribution at different host densities were estimated using the Green index. Multiple visits and ovipositions by females did not significantly affect the total number of progeny produced or their sex ratio. This study has generated novel information on egg laying, egg distribution and sex ratio of H. hebetor when reared on G. mellonella and has the potential to be used in the development of sustainable biological control programmes aimed at P. unionalis in olive orchards.