Effect of glycerol on protein acetylation by acetic anhydride

We investigated the basis for the previously unexplained stabilization of proteins by glycerol during reaction with acetic anhydride [S. Siegel and W. M. Award, Jr. (1973) J. Biol. Chem. 248, 3233-3240]. Model studies showed that glycerol competes successfully for acetylation against protein hydroxyl groups. In contrast, amino groups are much more potent nucleophiles and their acetylation is not apparently affected. Since alpha-amino and phenolic pKa's did not change significantly in increasing glycerol concentrations, these findings are ascribed to glycerol's lower pKa value as compared to water, leading to the decreased acetylation of tyrosine, threonine, and serine hydroxyl groups in Pronase guanidine-stable chymoelastase. An additional mechanism is important and predominates in the protection against inactivation of bovine delta-chymotrypsin during acetylation and is explained by the recently described basis for protein stabilization in glycerol [K. Gekko and S. N. Timasheff (1981) Biochemistry 20, 4667-4676; 4677-4686]. Those studies demonstrated that glycerol increased the hydrophobicity of nonpolar residues, augmenting their tendency to be removed from protein surfaces. Therefore, the stabilization afforded by glycerol for chymotrypsin is attributed in part to a favoring of the native folded state which forces the side chains of isoleucine-16 and valine-17 to be buried, increasing the apparent pKa of the alpha-amino group of isoleucine-16 as it forms the charge pair with the beta-carboxyl group of aspartate-194. This conclusion was supported by stopped-flow analyses of the interaction of delta-chymotrypsin with proflavin in increasing concentrations of glycerol.     

Weak seed banks influence the signature and detectability of selective sweeps

Seed banking (or dormancy) is a widespread bet-hedging strategy, generating a form of population overlap, which decreases the magnitude of genetic drift. The methodological complexity of integrating this trait implies it is ignored when developing tools to detect selective sweeps. But, as dormancy lengthens the ancestral recombination graph (ARG), increasing times to fixation, it can change the genomic signatures of selection. To detect genes under positive selection in seed banking species it is important to (1) determine whether the efficacy of selection is affected, and (2) predict the patterns of nucleotide diversity at and around positively selected alleles. We present the first tree sequence-based simulation program integrating a weak seed bank to examine the dynamics and genomic footprints of beneficial alleles in a finite population. We find that seed banking does not affect the probability of fixation and confirm expectations of increased times to fixation. We also confirm earlier findings that, for strong selection, the times to fixation are not scaled by the inbreeding effective population size in the presence of seed banks, but are shorter than would be expected. As seed banking increases the effective recombination rate, footprints of sweeps appear narrower around the selected sites and due to the scaling of the ARG are detectable for longer periods of time. The developed simulation tool can be used to predict the footprints of selection and draw statistical inference of past evolutionary events in plants, invertebrates, or fungi with seed banks.     

The beneficial effects of a multistrain potential probiotic,formic, and lactic acids with different vaccination regimens on broiler chickens challenged with multidrug-resistant Escherichia coli and Salmonella

The effects of a multistrain potential probiotic (Protexin®), acids, and a bacterin from multidrug-resistant E. coli O26, O78, S. Enteritidis (1,9,12 g.m1,7), and S. Typhimurium (1,4,5,12.i.1,2) on the immune response, haematological parameters, cytokines, and growth parameters of broiler chickens challenged with bacterin live serotypes were investigated. Two experiments were designed using 300 one-day-old chicks (Arbor Acres) randomly assigned to 15 groups. The first experiment comprised 9 groups, including positive and negative control groups and other groups received Protexin®, acids, and the bacterin (0.2 ml/SC), either alone or in combination, on the 1st day. The second experiment contained 6 groups, including positive and negative control groups and other groups received a combination of Protexin®, acids, and the bacterin (0.5 ml/SC) on the 8th day. All the groups except the negative control groups were challenged on the 8th and 16th days in both experiments, respectively, with mixed live bacterin serotypes. The groups that received Protexin®, acids, and the bacterin either alone or in combination revealed significant improvements in the immune response to the bacterin (p ≤ 0.05). The groups in the 1st experiment and most the 2nd experiment groups showed a reduced mortality rate and decreased levels IFN-γ, IL-4, and IL-12 cytokines (p ≤ 0.05). Moreover, these groups demonstrated increases in haematological parameters and reduced rates of infection-caused anaemia. These groups showed significant increases in growth performance parameters, such as body weight, weight gain, and the feed conversion ratio (FCR) (p ≤ 0.05). There was a beneficial effect on 1-day-old chickens produced by combining Protexin®, acids, and the bacterin (0.2 ml/SC).     

A Literature Review of Factors Associated With Pain From Fine Needle Aspiration Biopsy of Thyroid Nodules

ObjectiveThyroid nodules are common, being detected in 19% to 67% of the population. A fine needle aspiration biopsy (FNAB) is recommended for suspicious thyroid nodules to rule out malignancy; however, the procedure can be painful for subsets of patients. It remains unclear what factors are more likely to be associated with pain during FNAB. This literature review aimed to investigate patient-, procedure-, and analgesic-related factors that affect pain levels during thyroid nodule FNAB.MethodsPredefined inclusion and exclusion criteria were set to search the Embase, MEDLINE, CINAHL, and Cochrane databases. The articles evaluating the factors affecting pain during FNAB were assessed for inclusion. The primary outcome of interest was scores evaluating pain level during FNAB.ResultsTwenty-two studies were included. The studies were a mix of cohort studies, randomized controlled trials, and clinical controlled trials. Under patient-related factor, nodule calcification was associated with increasing pain. The procedure-related factors potentially increasing pain included the number of needle passes and utilization of the aspiration technique (as opposed to capillary action), perpendicular needle placement (as opposed to parallel), and not using safety devices. Larger needle size, type of biopsy, operator expertise, and patient education did not appear to be correlated with pain. Subcutaneous lidocaine appeared to provide better pain relief than a topical analgesic.ConclusionWith increasing use of FNAB as the diagnostic test of choice for assessing thyroid nodules, understanding patient-, procedure-, and analgesic-related factors associated with optimal patient satisfaction is imperative.     

Some practical aspects of measurements of betaines and their sulphur analogues by the use of HPLC

Recent interest in the analysis of glycinebetaine in algae has stimulated the search for improved methods of assaying betaines. A method based on high-performance liquid chromatographic (HPLC) separation using commercial columns and guard columns is described in detail for the newcomer. The methods is sensitive, reproducible and flexible enough to allow for minor differences among different HPLC pump systems.     

The problem of catheter encrustation

Catheter encrustation was studied in a group of long-stay hospital patients using both latex and silicone catheters. Moisture accounted for 80% by weight of the encrusted material with both catheters. Of the dry weight 90% was composed of protein, calcium, phosphorus, magnesium and uric acid. No relationship was found between the amounts of these substances in the urine and in the encrusted material. High levels of calcium, phosphorus and magnesium were found in the encrusted material from patients infected with Proteus organisms. No direct relationship was found between the duration of catheter drainage and the degree of encrustation, and there was a variation in patient susceptibility to encrustation irrespective of the catheter material. There was significantly less encrustation associated with silicone catheters.     

Evaluation of serum Nestin and HOTAIR rs12826786 C>T polymorphism as screening tools for breast cancer in Egyptian women

BackgroundNestin is a neural stem cell protein that plays an important role in cancer stem cells (CSC) development and proliferation. It has been identified as a marker for newly formed endothelial cells and was shown to be preferentially expressed in basal and myoepithelial cells of the mammary gland. HOTAIR is long intergenic non-coding (linRNA) associated with tumorigenesis through promotion of epithelial-mesenchymal transition (EMT) and stemness as well. HOTAIR gene contains a functioning single nucleotide polymorphic site rs12826786 C>T that has been associated with several cancer types.MethodsWe evaluated serum Nestin and the HOTAIR rs12826786 C>T polymorphism in healthy Egyptian women and those with breast cancer as a possible screening tool to identify patients with breast cancer. Also, we tested the possible association of the two markers with each other and the aggressiveness of the disease.ResultsPatients with breast cancer had a median (Min-Max) of serum Nestin 31.3 (6.7-167.3 pg/mL), while control subjects had a median (Min-Max) of serum Nestin 42.3 (25.7-315.95) pg/mL. The best cut-off value for serum Nestin to differentiate normal subjects and patients with breast cancer was 39.9 pg/mL. This cut-off value had a diagnostic sensitivity of 84.8% and specificity of 65.1%. There was a significant difference in the distribution of different alleles in patients with breast cancer than normal subjects (P=0.039 Exact Fisher test). The breast cancer patients group had 23.9% CC, 52.1% CT, and 23.9% TT genotypes, respectively, while the control group had 46.9% CC, 42.8% CT, and 10.2% TT, respectively.ConclusionsA significantly low serum Nestin below 39.9 pg/mL and a higher percentage of the T/T homozygous variant allele of HOTAIR rs12826786 C>T were found in Egyptian patients with breast cancer. We suggest that the reported cut-off value of serum Nestin and the presence of C/T polymorphism can be used to assess the risk of females for developing breast cancer and might be of potential benefit in screening the disease. Larger studies in different ethnic groups are needed to confirm our findings.