Identification of novel telomeric G-quadruplex-targeting chemical scaffolds through screening of three NCI libraries

Thirteen compounds with diverse chemical structures have been identified as selective telomeric G-quadruplex-binding ligands through screening the NCI Diversity Set II, the NCI Natural Products Set II and the NCI Mechanistic Diversity Set libraries containing a total of 2307 members against a human telomeric G-quadruplex using a FRET-based DNA melting assay. These compounds show significant selectivity towards a telomeric G-quadruplex compared to duplex DNA, fall within a molecular weight range of 327-533, and are generally consistent with the Lipinski Rule of Five for drug-likeness. Thus they provide new chemical scaffolds for the development of novel classes of G-quadruplex-targeting agents.     

Swarming generates rebel workers in honeybees

According to kin selection theory, the colony kin structure of eusocial insects motivates workers' altruistic behaviors and therefore their sterility or restricted reproduction [1]. Indeed, theory and cross-species comparison confirm that workers engage in their own reproduction depending on relatedness among colony members [2, 3]. We show that in a honeybee colony, the workers switch from their typical altruistic role to a more selfish one if at their larval stage there are environmental cues of an upcoming decline in intracolony relatedness. This happens inevitably when a colony multiplies by swarming and replaces the mother queen with her daughter, because the mother queen's workers are faced with rearing the sister queen's offspring related to them half as much as between sisters. Workers developing from the mother queen's eggs immediately after swarming, in a temporarily queenless colony, had more ovarioles in their ovaries and less-developed hypopharyngeal glands producing brood food than control workers reared in queenright conditions. These "rebel" workers were more engaged in laying their own male-determined eggs than in rearing offspring, whether or not the sister queen was present in the colony. The finding of this previously unknown rebel strategy confirms that kin selection shapes both cooperation and conflict in honeybee societies.     

Impact of IL28B-related single nucleotide polymorphisms on liver histopathology in chronic hepatitis C genotype 2 and 3

Background and Aims

Recently, several genome-wide association studies have revealed that single nucleotide polymorphisms (SNPs) in proximity to IL28B predict spontaneous clearance of HCV infection as well as outcome following peginterferon and ribavirin therapy among HCV genotype 1 infected patients. The present study aimed to evaluate the impact of IL28B SNP variability on liver histology in the context of a phase III treatment trial (NORDynamIC) for treatment-naïve patients with chronic HCV genotype 2 or 3 infection, where pretreatment liver biopsies were mandatory.

Methods

Three hundred and thirty-nine Caucasian patients had samples available for IL28B genotyping (rs12979860) of whom 314 had pretreatment liver biopsies that were evaluated using the Ishak protocol, allowing for detailed grading and staging of liver histopathology.

Results

IL28B CC_rs12979860 genotype in HCV genotype 3 infected patients was associated with higher ALT levels (p<0.0001), higher AST to platelet ratio index (APRI; p = 0.001), and higher baseline viral load (p<0.0001) as compared to patients with the CT or TT genotypes. Additionally the CC_rs12979860 genotype entailed more pronounced portal inflammation (p = 0.02) and steatosis (p = 0.03). None of these associations were noted among HCV genotype 2 infected patients.

Conclusion

This study shows that the CC_rs12979860 SNP is associated with more pronounced liver histopathology in patients chronically infected with HCV genotype 3, which may be secondary to higher viral load. The finding that IL28B variability did not impact on liver pathology or viral load among genotype 2 infected patients implies that IL28B may differentially regulate the course of genotype 2 and 3 infection.     

Lineage-specific fragmentation and nuclear relocation of the mitochondrial cox2 gene in chlorophycean green algae (Chlorophyta)

In most eukaryotes the subunit 2 of cytochrome c oxidase (COX2) is encoded in intact mitochondrial genes. Some green algae, however, exhibit split cox2 genes (cox2a and cox2b) encoding two polypeptides (COX2A and COX2B) that form a heterodimeric COX2 subunit. Here, we analyzed the distribution of intact and split cox2 gene sequences in 39 phylogenetically diverse green algae in phylum Chlorophyta obtained from databases (28 sequences from 22 taxa) and from new cox2 data generated in this work (23 sequences from 18 taxa). Our results support previous observations based on a smaller number of taxa, indicating that algae in classes Prasinophyceae, Ulvophyceae, and Trebouxiophyceae contain orthodox, intact mitochondrial cox2 genes. In contrast, all of the algae in Chlorophyceae that we examined exhibited split cox2 genes, and could be separated into two groups: one that has a mitochondrion-localized cox2a gene and a nucleus-localized cox2b gene ("Scenedesmus-like"), and another that has both cox2a and cox2b genes in the nucleus ("Chlamydomonas-like"). The location of the split cox2a and cox2b genes was inferred using five different criteria: differences in amino acid sequences, codon usage (mitochondrial vs. nuclear), codon preference (third position frequencies), presence of nucleotide sequences encoding mitochondrial targeting sequences and presence of spliceosomal introns. Distinct green algae could be grouped according to the form of cox2 gene they contain: intact or fragmented, mitochondrion- or nucleus-localized, and intron-containing or intron-less. We present a model describing the events that led to mitochondrial cox2 gene fragmentation and the independent and sequential migration of cox2a and cox2b genes to the nucleus in chlorophycean green algae. We also suggest that the distribution of the different forms of the cox2 gene provides important insights into the phylogenetic relationships among major groups of Chlorophyceae.     

A comparative analysis of proteins that accumulate during the initial stage of root hair development in barley root hair mutants and their parent varieties

The mechanisms of root hair formation have been studied extensively in Arabidopsis but knowledge about these processes in monocot species is still limited, especially in relation to the proteome level. The aim of this study was to identify the proteins that are involved in the initiation and the early stage of root hair tip growth in barley using two-dimensional (2D) electrophoresis and mass spectrometry. A comparison of proteins that accumulate differentially in two root hair mutants and their respective parent varieties resulted in the identification of 13 proteins that take part in several processes related to the root hair morphogenesis, such as the control of vesicular trafficking, ROS signalling and homeostasis, signal transduction by phospholipids metabolism and ATP synthesis. Among the identified proteins, two ATP synthases, two ABC transporters, a small GTPase from the SAR1 family, a PDI-like protein, a monodehydroascorbate reductase, a C2 domain-containing protein and a Wali7 domain-containing protein were found. This study is the first report on the proteins identified in the initial stage of root hair formation in barley and gives new insights into the mechanisms of root hair morphogenesis in a monocot species.     

Metabolic footprint of <Emphasis Type="Italic">Lactobacillus acidophilus</Emphasis> NCFM at different pH

Lactobacillus acidophilus NCFM is a well known microorganism from the genomic and probiotic point of view. In order to analyze the potential interactions of NCFM with the surrounding environment, in vitro tests with the metabolic footprinting approach were performed. It was found that NCFM increased the concentration of lactic acid, succinic acid, adenine and arginine in the medium. The metabolism of NCFM did not change significantly between pH 5 and 7, suggesting that other environmental factors than pH might have bigger impact on its colonization throughout the gastrointestinal tract.     

Duodenal expression of iron transport molecules in patients with hereditary hemochromatosis or iron deficiency

Disturbances of iron metabolism are observed in chronic liver diseases. In the present study, we examined gene expression of duodenal iron transport molecules and hepcidin in patients with hereditary hemochromatosis (HHC) (treated and untreated), involving various genotypes (genotypes which represent risk for HHC were examined), and in patients with iron deficiency anaemia (IDA). Gene expressions of DMT1, ferroportin, Dcytb, hephaestin, HFE and TFR1 were measured in duodenal biopsies using real-time PCR and Western blot. Serum hepcidin levels were measured using ELISA. DMT1, ferroportin and TFR1 mRNA levels were significantly increased in post-phlebotomized hemochromatics relative to controls. mRNAs of all tested molecules were significantly increased in patients with IDA compared to controls. The protein expression of ferroportin was increased in both groups of patients but not significantly. Spearman rank correlations showed that DMT1 versus ferroportin, Dcytb versus hephaestin and DMT1 versus TFR1 mRNAs were positively correlated regardless of the underlying cause, similarly to protein levels of ferroportin versus Dcytb and ferroportin versus hephaestin. Serum ferritin was negatively correlated with DMT1 mRNA in investigated groups of patients, except for HHC group. A decrease of serum hepcidin was observed in IDA patients, but this was not statistically significant. Our data showed that although untreated HHC patients do not have increased mRNA levels of iron transport molecules when compared to normal subjects, the expression is relatively increased in relation to body iron stores. On the other hand, post-phlebotomized HHC patients had increased DMT1 and ferroportin mRNA levels possibly due to stimulated erythropoiesis after phlebotomy.     

Expression of ghrelin receptor (GHSR-1a) in rat epididymal spermatozoa and the effects of its activation

In this study we demonstrated the expression of the ghrelin receptor GHSR-1a in rat spermatids and epididymal spermatozoa, as well as some effects of ghrelin on the spermatozoa in vitro. For the demonstration of GHSR-1a the immunocytochemical, immunofluorescence and Western blotting techniques were applied using three different types of antibodies. The response of spermatozoa to ghrelin was tested in a series of in vitro experiments and their effects were evaluated using confocal microscopy and flow cytometry. GHSR-1a protein was found as expressed in the Golgi and acrosomes of spermatids and acrosome regions or the head cell membrane of epididymal spermatozoa. The GHSR-1a expression in spermatozoa was also confirmed by Western blot. No differences were found in percentage of spermatozoa showing annexin-V binding and expression of active form caspase-3 between control and ghrelin-treated spermatozoa. This result may indicate no pro-apoptotic effects of ghrelin neither at 10^?9 nor 10^?6 mol/L concentration. Ghrelin (10^?6 mol/L) increased free intracellular calcium ion concentration in the rat spermatozoa. Moreover, stimulation with 10^?6 mol/L ghrelin increased, while 10^?4 mol/L ghrelin decreased the number of spermatozoa showing progressive motility. In conclusion, the expression of the GHSR-1a receptor in spermatozoa, as well as ghrelin influences on sperm motility and intracellular calcium ion concentration suggest that such biological effects of ghrelin may be produced under in vivo conditions.