Capsule Type of Streptococcus pneumoniae Determines Growth Phenotype

The polysaccharide capsule of Streptococcus pneumoniae defines over ninety serotypes, which differ in their carriage prevalence and invasiveness for poorly understood reasons. Recently, an inverse correlation between carriage prevalence and oligosaccharide structure of a given capsule has been described. Our previous work suggested a link between serotype and growth in vitro. Here we investigate whether capsule production interferes with growth in vitro and whether this predicts carriage prevalence in vivo. Eighty-one capsule switch mutants were constructed representing nine different serotypes, five of low (4, 7F, 14, 15, 18C) and four of high carriage prevalence (6B, 9V, 19F, 23F). Growth (length of lag phase, maximum optical density) of wildtype strains, nontypeable mutants and capsule switch mutants was studied in nutrient-restricted Lacks medium (MLM) and in rich undefined brain heart infusion broth supplemented with 5% foetal calf serum (BHI+FCS). In MLM growth phenotype depended on, and was transferred with, capsule operon type. Colonization efficiency of mouse nasopharynx also depended on, and was transferred with, capsule operon type. Capsule production interfered with growth, which correlated inversely with serotype-specific carriage prevalence. Serotypes with better growth and higher carriage prevalence produced thicker capsules (by electron microscopy, FITC-dextran exclusion assays and HPLC) than serotypes with delayed growth and low carriage prevalence. However, expression of cpsA, the first capsule gene, (by quantitative RT-PCR) correlated inversely with capsule thickness. Energy spent for capsule production (incorporation of H3-glucose) relative to amount of capsule produced was higher for serotypes with low carriage prevalence. Experiments in BHI+FCS showed overall better bacterial growth and more capsule production than growth in MLM and differences between serotypes were no longer apparent. Production of polysaccharide capsule in S. pneumoniae interferes with growth in nutrient-limiting conditions probably by competition for energy against the central metabolism. Serotype-specific nasopharyngeal carriage prevalence in vivo is predicted by the growth phenotype.     

LC/MS/MS Phenolic Profile,Antioxidant Capacity,Angiotensin-Converting Enzyme (ACE) and Glutathione S Transferase (GST) Inhibitory Properties of Ultrasound-Assisted Propolis Extracts

Resinous beehive product propolis has many biological activities. It contains various aromatic substances that have great differences in their chemical composition depending on the natural flora. Thus, chemical characterization and biological properties of propolis samples is an important subject for the pharmaceutical industry. In this study, the propolis samples collected from three cities in Turkey were prepared as methanol (MEP), ethanol (EEP), chloroform (ChlEP), hexane (HxEP), and ethyl acetate (EAEP) extracts using an ultrasonic assisted technique. The antioxidant capacities of the samples were evaluated by free radical scavenging activity (DPPH), cation radical scavenging activity (ABTS), and reducing activity (CUPRAC) and (FRAP). The strongest biological activities were detected in ethanol and methanol extracts. Enzyme inhibition of the propolis samples were determined against the human glutathione S-transferase (GST) and angiotensin converting enzyme (ACE). IC₅₀ values of MEP1, MEP2, and MEP3 samples against the ACE were found as 13.9 μg/mL, 14.8 μg/mL, and 12.8 μg/mL, while against the GST IC₅₀ values of MEP1, MEP2, and MEP3 samples were as 5.92 μg/mL, 9.49 μg/mL, and 5.72 μg/mL. To know the possible causes of the biological test results advanced LC/MS/MS method was applied. trans-ferulic acid, kaempferol, and chrysin were found as the most abundant phenolic compounds in each sample. The propolis extracts obtained using the proper solvent have a good potential to be used in pharmaceuticals to treat the diseases related to oxidative damage, hypertension, and inflammation. Finally, the interactions between chrysin, trans-ferulic acid and kaempferol molecules with ACE and GST receptors were analyzed using molecular docking study. Selected molecules interact with active residues by binding to the active site of the receptors.     

Metabolic responses to prolonged starvation, food restriction, and refeeding in the brown trout, Salmo trutta: oxidative stress and antioxidant defenses

The effects of long-term starvation and food restriction (49 days), followed by refeeding (21 days) have been studied with respect to antioxidant defense in the liver and gills (branchial tissues) of the brown trout, Salmo trutta. Malondialdehyde levels in both tissues increased in parallel with starvation and food restriction and these values did not return to normal after the refeeding period. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in liver and gills increased during the 49 days of starvation, but glucose-6-phosphate dehydrogenase (G6PD) activities decreased. Glutathione S-transferase (GST) activity decreased in the liver at the 49th day of starvation, but increased in the branchial tissues. Some of the antioxidant enzyme activities (such as hepatic GST and branchial G6PD) returned to control values of fed fish after the refeeding period, but others (e.g. hepatic SOD and branchial GPx) did not return to normal values. In conclusion, our study indicates that total or partial food deprivation induces oxidative stress in brown trout.     

Characterization of hawthorn (<Emphasis Type="Italic">Crataegus</Emphasis> spp.) genotypes by SSR markers

Hawthorn (Crataegus spp.) is an edible wild fruit that is used in traditional medicine, landscape studies, and food and beverage industries in many countries. It is an important wild plant species in Turkey and is numerous in the Yozgat Province. Genetic and breeding studies on hawthorn are very limited. Therefore, we aimed to characterize 91 hawthorn genotypes using simple sequence repeat (SSR) markers. The SSRs were developed from apple and pear and were screened in hawthorn for amplification and polymorphisms. A total of 265 alleles were detected from thirty-two SSR primer pairs, and those were used to identify genetic relationships. The number of alleles ranged from 2 to 21 alleles per locus with a mean value of 8.28. The Hi05b09 locus showed the highest allele number (Na?=?21). The polymorphism information content (PIC) values ranged from 0.16 (CH03d10) to 0.89 (C6554) with a mean value of 0.60. An Unweighted Pair Group Method with Arithmetic Average method was used to cluster the genotypes, and four major clusters were obtained from the amplification of the SSRs. STRUCTURE software identified four populations (ΔK?=?4) and eight sub-populations (ΔK?=?8), and four major clusters similar results to UPGMA analysis. Our study showed that the SSR markers could be utilized as a reliable tool for the determination of genetic variations and relationships of hawthorn genotypes. A basic molecular analysis on the hawthorn genotypes identified in this study will promote the collection of germplasm collection and the selection of parents’ in future cross-breeding studies.     

Exploring genetic diversity and Population structure of five Aegilops species with inter-primer binding site (iPBS) markers

Molecular Biology Reports - Turkey is not only a center of origin for wheat, but also contains wild forms of various cereals. Turkey, located in the Fertile Crescent, has conserved its genetic...     

Sexual responses of the male rat medial preoptic area and medial amygdala to estrogen I: site specific suppression of estrogen receptor alpha

Male rat copulation is mediated by estrogen-sensitive neurons in the medial preoptic area (MPO) and medial amygdala (MEA); however, the mechanisms through which estradiol (E(2)) acts are not fully understood. We hypothesized that E(2) acts through estrogen receptor α (ERα) in the MPO and MEA to promote male mating behavior. Antisense oligodeoxynucleotides (AS-ODN) complementary to ERα mRNA were bilaterally infused via minipumps into either brain area to block the synthesis of ERα, which we predicted would reduce mating. Western blot analysis and immunocytochemistry revealed a knockdown of ERα expression in each brain region; however, compared to saline controls, males receiving AS-ODN to the MPO showed significant reductions in all components of mating, whereas males receiving AS-ODN to the MEA continued to mate normally. These results suggest that E(2) acts differently in these brain regions to promote the expression of male rat sexual behavior and that ERα in the MPO, but not in the MEA, promotes mating.     

Carboxymethylcellulose–gelatin–superoxidase dismutase electrode for amperometric superoxide radical sensing

A novel, highly sensitive superoxide dismutase biosensor for the direct and simultaneous determination of superoxide radicals was developed by immobilization of superoxide dismutase within carboxymethylcellulose-gelatin on a Pt electrode surface. The parameters affecting the performance of the biosensor were investigated. The response of the CMC-G-SOD biosensor was proportional to O (2) (·-) concentration and the detection limit was 1.25 × 10(-3) mM with a correlation coefficient of 0.9994. The developed biosensor exhibited high analytical performance with wider linear range, high sensitivity and low response time. The biosensor retained 89.8% of its sensitivity after use for 80 days. The support system enhanced the immobilization of superoxide dismutase and promoted the electron transfer of superoxide dismutase minimizing its fouling effect. The biosensor was quite effective not only in detecting O (2) (·-) , but also in determining the antioxidant properties of acetylsalicylic acid-based drugs and the anti-radical activity of healthy and cancerous human brain tissues.     

Cholecystokinin- and gastrin-induced protein and amylase secretion from the parotid gland of the anaesthetized rat

I.V. infusion of pentagastrin (20 microg/kg/h) or cholecystokinin (CCK)-8 (1 microg/kg/h) for 10 min caused secretion of salivary proteins from the parotid gland in the anaesthetized rat without any accompanying overt fluid secretion. This "occult" response was revealed by a subsequent wash-out injection of methacholine (5 microg/kg, I.V.) 10 min after the end of the infusion period (aiming at avoiding synergistic interactions). While the fluid response to methacholine was unaffected by the preceding infusion of pentagastrin and CCK-8, the output of protein increased by 147% (pentagastrin) and 74% (CCK-8) and that of amylase by 45% (CCK-8) compared to the responses to methacholine upon saline infusion. Those increases were abolished by the CCK-A receptor blocker (lorglumide), but not by the CCK-B receptor blocker (itriglumide). Evisceration, combined sympathetic and parasympathetic denervation of the glands and assay under adrenoceptor blockade excluded contribution from the gastro-intestinal tract, central or ganglionic mechanisms and circulating catecholamines to the increase in protein/amylase. Furthermore, Western blot demonstrated CCK receptors for both A and B subtypes in normal and chronically denervated glands. In the submandibular gland, both pentagastrin and CCK-8 evoked a trace secretion of saliva but, under the present experimental set-up, no statistically significant increase in protein output. Thus, in addition to the autonomic nervous system, gastrointestinal hormones may, in some types of glands, be involved in the secretion of salivary gland proteins.     

Seasonal changes in antioxidant defence system of liver and gills of Salmo trutta caspius, Salmo trutta labrax and Salmo trutta macrostigma

Seasonal changes in antioxidant enzyme activities (superoxide dismutase, SOD, EC 1.15.1.1; catalase, CAT, EC 1.11.1.16; glutathione peroxidase, GPx, EC 1.11.1.9; glutathione reductase, GR, EC 1.6.4.2; glucose-6-phosphate dehydrogenase, G6PD, EC 1.1.1.49 and glutathione S -transferase, GST, EC 1.5.1.18) and lipid peroxidation (LPO) levels of livers and gills of female Caspian trout Salmo trutta caspius , Black Sea trout Salmo trutta labrax and mountain trout Salmo trutta macrostigma were investigated. SOD, CAT, GPx, G6PD and GST activities were higher in liver compared to gills of all sub-species; concomitantly, the GR activity was also higher in the livers of S. t. caspius and S. t. labrax , but the reverse was seen in S. t. macrostigma . LPO levels were higher in the gills compared to the liver of all sub-species. There was no general trend in the seasonal changes in the gill antioxidant enzyme (AE) activities or LPO levels. Higher AE activities, however, were found in the liver of each sub-species during autumn, and this coincided with an increase in the gonado-somatic index.     

Effect of host species on recG phenotypes in Helicobacter pylori and Escherichia coli

Recombination is a fundamental mechanism for the generation of genetic variation. Helicobacter pylori strains have different frequencies of intragenomic recombination, arising from deletions and duplications between DNA repeat sequences, as well as intergenomic recombination, facilitated by their natural competence. We identified a gene, hp1523, that influences recombination frequencies in this highly diverse bacterium and demonstrate its importance in maintaining genomic integrity by limiting recombination events. HP1523 shows homology to RecG, an ATP-dependent helicase that in Escherichia coli allows repair of damaged replication forks to proceed without recourse to potentially mutagenic recombination. Cross-species studies done show that hp1523 can complement E. coli recG mutants in trans to the same extent as E. coli recG can, indicating that hp1523 has recG function. The E. coli recG gene only partially complements the hp1523 mutation in H. pylori. Unlike other recG homologs, hp1523 is not involved in DNA repair in H. pylori, although it has the ability to repair DNA when expressed in E. coli. Therefore, host context appears critical in defining the function of recG. The fact that in E. coli recG phenotypes are not constant in other species indicates the diverse roles for conserved recombination genes in prokaryotic evolution.