Conformational behaviours of 2-substituted cyclohexanones: a complete basis set,hybrid-DFT study and NBO interpretation

The generalised anomeric effect (GAE) and gauche effect (GE) associated with donor–acceptor delocalisations, dipole–dipole interactions and total steric exchange energies (TSEE) on the conformational properties of 2-methoxy- (1), 2-methylthio- (2), 2-methylseleno- (3), 2-fluoro- (4), 2-chloro- (5) and 2-bromocyclohexanone (6) have been studied by means of ab initio and hybrid density functional theory methods and natural bond orbital (NBO) analysis. All methods used showed that the axial conformation stability increased from 2-methoxy- (1) to 2-methylselenocyclohexanone (3) and also from 2-fluoro- (4) to 2-bromocyclohexanone (6), which is in agreement with reported NMR data. The results obtained by complete basis set 4 (CBS-4), B3LYP/6-311+G** and HF/6-311+G** levels for compounds 1, 5 and 6 are very similar, but the CBS-4 results for compound 4 are not in agreement with the reported experimental data (vapour phase). The NBO analysis showed that the GAE increases from compounds 1 to 3 and also from compounds 4 to 6. The low axial conformer populations of compounds 1 and 4 can be reasonably explained by their small GAE. GE does not have significant impact on the conformational behaviours of compounds 1–6 and GAE succeeds in accounting qualitatively for the increase in the axial preferences in both series of compounds. The results showed that the calculated Δ(TSEE_eq–ax) values decrease from compounds 4 to 6 which contradicts the suggested arguments in the literature about these compounds. On the other hand, the calculated differences between the dipole moment values of the axial and equatorial conformations, Δ(μ_eq ? μ_ax), increase from compounds 1 to 2, but decrease from compounds 2 to 3 and also decrease from compounds 4 to 6. The calculated GAE values are more significant for the explanation of the conformational preferences of compounds 1–6 than the dipole–dipole repulsion effects. The correlations between the GAE, GE, dipole–dipole interactions, Wiberg Bond Index, TSEE, donor and acceptor orbital energies and occupancies, structural parameters and conformational behaviour of compounds 1–6 have been investigated.     

Biocompatible scaffolds based on collagen and oxidized dextran for endothelial cell survival and function in tissue engineering

Angiogenesis is a vital step in tissue regeneration. Hence, the current study aimed to prepare oxidized dextran (Odex)/collagen (Col)-hydrogels with laminin (LMN), as an angiogenic extracellular matrix (ECM) component, for promoting human umbilical vein endothelial cell (HUVEC) proliferation and function. Odex/Col scaffolds were constructed at various concentrations and temperatures. Using oscillatory rheometry, scanning electron microscopy (SEM), and cell viability testing, the scaffolds were characterized, and then HUVEC proliferation and function was compared with or without LMN. The gelation time could be modified by altering the Odex/Col mass ratio as well as the temperature. SEM showed that Odex/Col hydrogels had a more regular three-dimensional (3D) porous structure than the Col hydrogels. Moreover, HUVECs grew faster in the Col scaffold (12 mg/mL), whereas the Odex (30 mg/mL)/Col (6 mg/mL) scaffold exhibited the lowest apoptosis index. Furthermore, the expression level of vascular endothelial growth factor (VEGF) mRNA in the group without LMN was higher than that with LMN, and the Odex (30 mg/mL)/Col (6 mg/mL) scaffold without LMN had the highest VEGF protein secretion, allowing the cells to survive and function effectively. Odex/Col scaffolds, with or without LMN, are proposed as a tissue engineering construct to improve HUVEC survival and function for angiogenesis.     

Absolute Leukocyte Telomere Length in HIV-Infected and Uninfected Individuals: Evidence of Accelerated Cell Senescence in HIV-Associated Chronic Obstructive Pulmonary Disease

Combination antiretroviral therapy (cART) has extended the longevity of human immunodeficiency virus (HIV)-infected individuals. However, this has resulted in greater awareness of age-associated diseases such as chronic obstructive pulmonary disease (COPD). Accelerated cellular senescence may be responsible, but its magnitude as measured by leukocyte telomere length is unknown and its relationship to HIV-associated COPD has not yet been established. We measured absolute telomere length (aTL) in peripheral leukocytes from 231 HIV-infected adults. Comparisons were made to 691 HIV-uninfected individuals from a population-based sample. Subject quartiles of aTL were assessed for relationships with measures of HIV disease severity, airflow obstruction, and emphysema severity on computed tomographic (CT) imaging. Multivariable regression models identified factors associated with shortened aTL. Compared to HIV-uninfected subjects, the mean aTL in HIV-infected patients was markedly shorter by 27 kbp/genome (p<0.001); however, the slopes of aTL vs. age were not different (p=0.469). Patients with longer known durations of HIV infection (p=0.019) and lower nadir CD4 cell counts (p=0.023) had shorter aTL. Shorter aTL were also associated with older age (p=0.026), smoking (p=0.005), reduced forced expiratory volume in one second (p=0.030), and worse CT emphysema severity score (p=0.049). HIV-infected subjects demonstrate advanced cellular aging, yet in a cART-treated cohort, the relationship between aTL and age appears no different from that of HIV-uninfected subjects.     

DNA cleavage of a cryptic recombination signal sequence by RAG1 and RAG2. Implications for partial V(H) gene replacement

Antibody and T cell receptor genes are assembled from gene segments by V(D)J recombination to produce an almost infinitely diverse repertoire of antigen specificities. Recombination is initiated by cleavage of conserved recombination signal sequences (RSS) by RAG1 and RAG2 during lymphocyte development. Recent evidence demonstrates that recombination can occur at noncanonical RSS sites within Ig genes or at other loci, outside the context of normal lymphocyte receptor gene rearrangement. We have characterized the ability of the RAG proteins to bind and cleave a cryptic RSS (cRSS) located within an Ig V(H) gene segment. The RAG proteins bound with sequence specificity to either the consensus RSS or the cRSS. The RAG proteins nick the cRSS on both the top and bottom strands, thereby bypassing the formation of the DNA hairpin intermediate observed in RAG cleavage of canonical RSS substrates. We propose that the RAG proteins may utilize an alternative mechanism for double-stranded DNA cleavage, depending on the substrate sequence. These results have implications for further diversification of the antigen receptor repertoire as well as the role of the RAG proteins in genomic instability.     

Hydroethanolic extract of Psidium guajava leaf for induced osteoarthritis using a guinea pig model

We investigated the therapeutic effects of an extract of Psidium guajava (guava) leaf on experimentally induced osteoarthritis in guinea pig. The left knee of 30 male guinea pigs was anesthetized and the cranial cruciate ligament was severed. The animals were followed for 8 weeks until osteoarthritis was confirmed by radiography and histopathology. Animals were divided randomly into five groups; group 1, the ligament was severed and untreated; group 2, the ligament was severed and treated with piascledine, an extract of soybean and avocado; group 3, the ligament was severed and treated with 200 mg/kg hydroethanolic extract of guava; group 4, the ligament was severed and treated with 400 mg/kg hydroethanolic extract of guava; and group 5, control animals without surgery or extracts. Radiological and histopathological evaluations after 8 weeks showed reduced severity of osteoarthritis in the piascledine treatment group compared to group 1. The guava extract also reduce the severity of osteoarthritis compared to controls. Histopathological examination of treatment and control groups showed that treatment the guava extract improved lesions significantly. Hydroethanolic extracts of guava leaf appears to prevent osteoarthritis by inhibition of free radical formation in the knee joint.     

In Vitro Infectivity Assessment by Drug Susceptibility Comparison of Recombinant Leishmania major Expressing Enhanced Green Fluorescent Protein or EGFP-Luciferase Fused Genes with Wild-Type Parasite

Leishmaniasis is a worldwide uncontrolled parasitic disease due to the lack of effective drug and vaccine. To speed up effective drug development, we need powerful methods to rapidly assess drug effectiveness against the intracellular form of Leishmania in high throughput assays. Reporter gene technology has proven to be an excellent tool for drug screening in vitro. The effects of reporter proteins on parasite infectivity should be identified both in vitro and in vivo. In this research, we initially compared the infectivity rate of recombinant Leishmania major expressing stably enhanced green fluorescent protein (EGFP) alone or EGFP-luciferase (EGFP-LUC) with the wild-type strain. Next, we evaluated the sensitivity of these parasites to amphotericin B (AmB) as a standard drug in 2 parasitic phases, promastigote and amastigote. This comparison was made by MTT and nitric oxide (NO) assay and by quantifying the specific signals derived from reporter genes like EGFP intensity and luciferase activity. To study the amastigote form, both B10R and THP-1 macrophage cell lines were infected in the stationary phase and were exposed to AmB at different time points. Our results clearly revealed that the 3 parasite lines had similar in vitro infectivity rates with comparable parasite-induced levels of NO following interferon-γ/lipopolysaccharide induction. Based on our results we proposed the more reporter gene, the faster and more sensitive evaluation of the drug efficiency.     

The investigation of allele and genotype frequencies of <Emphasis Type=Italic>CYP3A5 (1*/3*)</Emphasis> and <Emphasis Type=Italic>P2Y12</Emphasis> (T744C) in Iran

Research on the frequency of the highly functional mutations of genes coding required for metabolizing enzymes has shown significant ethnic variations. However, few studies, if any, have examined the frequency distribution of major allelic variations in the context of Iran. In this regard, the present study focused on the genotype profile of Southern Iranians in order to compare allele frequencies of their CYP3A5 and P2Y12 (T744C) which have been shown to have roles in metabolizing clopidogrel, with those of other populations. Therefore, genotyping was carried out on 112 unrelated individuals by PCR–RFLP. The CYP3A5*3 allele was found in 185 persons with allelic frequency 0.82, which is the most common allele among Caucasians (90–95%). The frequency of 82% is different from other Caucasians (90–94%), Indians (67%), Vietnam (67%) and Africans (15%). but lower than frequency in Chinese populations (74%) and Korean (76%). The allele frequency of the −744T (4%) is different from frequencies of Caucasian, American, Chinese, Korean, and Subsahara population. This study confirmed significant inter-ethnic differences in CYP3A5 and P2Y12 frequencies between Iranians and other ethnic groups. The results of this study will be useful for clinical pharmacokinetic investigations and drug dosage recommendations especially antiplatelet drugs such as Clopidogrel, for Iranians.     

SLC30A8 gene polymorphism (rs13266634 C/T) and type 2 diabetes mellitus in south Iranian population

Type 2 diabetes mellitus (T2DM) is a multifactorial metabolic disorder which is characterized by chronic hyperglycemia. T2DM is due to the interplay of genetic susceptibility and environmental factors. Zinc is an important element for insulin storage and secretion. Zinc transporters ensure zinc transportation across the biological membranes and enable the cellular flow of zinc into the extracellular matrix or the intracellular vesicles. Solute carrier family 30 member 8 (SLC30A8) gene encodes zinc transporter protein member 8. The rs13266634 C/T polymorphism in SLC30A8 gene has been reported with higher risk of T2DM in literature. Thus, the present study aimed to investigate the association between rs13266634 polymorphism and T2DM in Fars province, Southern Iran and compare the results with other populations. A total of 306 subjects were collected from the outpatients of Shahid Motahhari clinic affiliated to Shiraz University of Medical Sciences, Shiraz, Iran. These subjects were genotyped using polymerase chain reaction-restriction fragment length polymorphism and validated by direct sequencing. The frequency of CC genotype in diabetic and control groups was 90 (59.6 %) and 89 (57.4 %). The number of CT genotype was 51 (33.8 %) in the case and 49 (31.6 %) in the control group. The TT genotype was 10 (6.6 %) and 17 (11 %) in diabetic and non-diabetic subjects, respectively. No significant difference was found between the normal and T2DM subjects regarding the allelic and genotypic distribution (p = 0.35, OR = 1.19, 95 % CI 0.82–1.7) and (p = 0.94, OR = 1.7, 95 % CI 0.7–3.9). No significant difference was found between the normal and diabetic subjects regarding the rs13266634 C/T polymorphism in SLC30A8 gene. In comparison with other ethnic groups, the C allele frequency in our population was very similar to that of the European but higher than that of the Eastern Asian and lower than the African populations.     

Phage Shock Protein G,a Novel Ethanol-Induced Stress Protein in <Emphasis Type="Italic">Salmonella typhimurium</Emphasis>

Exposure to ethanol is a stress condition that Salmonella typhimurium often encounters during its life cycle. Food, beverage, drugs, and cosmetics have a long history of using alcohols to control pathogens. Ethanol is also commonly used for disinfecting medical instruments. This study was conducted to evaluate the ethanol stress variations on the protein profile, cell structure, and serologic features of S. typhimurium. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis revealed the phage shock protein G (pspG), a new ethanol-induced stress protein in cells adapted to 10% ethanol. The result was confirmed by liquid chromatography–mass spectrometry. The maximum quantity of this 9.02-kDa protein was produced in 12.5% (v/v) of ethanol-treated cultures. Scanning electron microscopy has demonstrated new phenotypic characteristics in bacterial structure. The cells were unable to undergo binary fission. This phenomenon explains the tight attachment of bacteria in a colony. Overall, ethanol extreme stress induced expression of new proteins like PspG and repression of some other proteins in S. typhimurium. These induction and repression processes have inflicted dramatic changes on Salmonella behaviors. Alireza Shoae Hassani, Kasra Hamdi and Amir Ghaemi are members of Young Researchers Club (YRC) of Tehran Science & Research Campus of IAU, Tehran, Iran.     

The association between adiponectin (+45T/G) and adiponectin receptor-2 (+795G/A) single nucleotide polymorphisms with cirrhosis in Iranian population

Adiponectin which possesses anti-inflammatory and insulin-sensitizing properties is elevated in blood circulation of liver cirrhosis patients. The genetic variations in the adiponectin gene can affect the circulating adiponectin level and stimulation of adiponectin receptor that may affect the activity of adiponectin. We investigated the effect of adiponectin single nucleotide polymorphisms (SNP) 45 T/G and adiponectin receptor-2 gene SNP 795G/A in cirrhotic Iranian population. A total of 97 cirrhotic patients and 128 healthy controls from Iranian population were genotyped for the adiponectin and adiponectin receptor 2 gene (+45T>G and 795G/A) by polymerase chain reaction-restriction fragment length polymorphism. G frequency was 21.1% versus 12.89% (P = 0.001) for SNP45, and G frequency was 75.8% versus 76.2% (P = 0.526) for SNP795G/A in the patients and control group, respectively. Based on our findings, the expression of the G allele at SNP45 is higher in the patient group compared with healthy subjects, suggesting that it may affect liver injury through changes in the plasma adiponectin level.