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Background  

In eukaryotes, histone H3 lysine 9 (H3K9) methylation is a common mechanism involved in gene silencing and the establishment of heterochromatin. The loci of the major heterochromatic H3K9 methyltransferase Su(var)3-9 and the functionally unrelated γ subunit of the translation initiation factor eIF2 are fused in Drosophila melanogaster. Here we examined the phylogenetic distribution of this unusual gene fusion and the molecular evolution of the H3K9 HMTase Su(var)3-9.  相似文献   

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Background  

It has been reported that calf oocytes are less developmentally competent than oocytes obtained from adult cows. Bone morphogenetic protein 15 (BMP15) and growth and differentiation factor 9 (GDF9) play critical roles in folliculogenesis, follicular development and ovulation in mammalian ovaries. In the present study, we attempted to compare the expression patterns of BMP15 and GDF9 in the cells of calf and cow ovaries to determine a relationship between the level of these genes and the low developmental competence of calf oocytes.  相似文献   

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Background  

The ornamental plant Gerbera hybrida bears complex inflorescences with morphologically distinct floral morphs that are specific to the sunflower family Asteraceae. We have previously characterized several MADS box genes that regulate floral development in Gerbera. To study further their behavior in higher order complex formation according to the quartet model, we performed yeast two- and three-hybrid analysis with fourteen Gerbera MADS domain proteins to analyze their protein-protein interaction potential.  相似文献   

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Background  

Glucose inhibition of gluconeogenic growth suppressor 2 protein (Gis2p) and zinc-finger protein 9 (ZNF9) are conserved yeast and human zinc-finger proteins. The function of yeast Gis2p is unknown, but human ZNF9 has been reported to bind nucleic acids, and mutations in the ZNF9 gene cause the neuromuscular disease myotonic dystrophy type 2. To explore the impact of these proteins on RNA regulation, we undertook a systematic analysis of the RNA targets and of the global implications for gene expression.  相似文献   

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Sunflower (Helianthus annuus) stem canker caused by Diaporthe helianthi is one of the most important sunflower diseases in Croatia. Until recently, sunflower was the only known host for D. helianthi. In our research carried out in the area of Eastern Croatia, isolates of Diaporthe/Phomospis were collected from Xanthium italicum, X. strumarium and Arctium lappa. Using morphological, cultural and molecular ITS rDNA data, isolates from these weeds were identified as D. helianthi. The following isolates were used in the pathogenicity test: one isolate originated from sunflower (Su5/04), three from X. italicum (Xa2, Xa3 and Xa5), two from X. strumarium (Xa9 and Xa12), one from Xanthium sp. (Xa13) and one from A. lappa (Ar3). According to the results, it was determined that isolate Xa5 (originated from X. italicum) was the most pathogenic to sunflower stems. The average length of the lesion was 11.3 cm. The lowest level of pathogenicity was found in Xa9 (isolated from X. strumarium). The length of the lesion was 0.1 cm.  相似文献   

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Background

Macrophage inhibitory factor (MIF) is a pro‐inflammatory cytokine modulating monocyte motility and a pleiotropic regulator of different biological and cellular processes. The MIF‐173G/C (rs755622) polymorphism is found in the promoter region and affects its activity. The present study investigated the MIF polymorphism as a risk factor for the development of acute lymphoblastic leukemia (ALL) in Egyptian children.

Methods

We analyzed the MIF‐173G/C (rs755622) polymorphism in 180 ALL cases and 150 healthy control children by amplification of the gene using a polymerase chain reaction followed by restriction endonuclease digestion and running on an agarose gel for visualization of the product.

Results

We found a significant incidence of the homozygous polymorphic (CC) genotype and the combined polymorphic genotypes (GC + CC) in ALL patients compared to healthy controls (p = 0.001 and p = 0.007, respectively), whereas the wild‐type genotype (GG) was more common in healthy controls (p = 0.006). Multivariate logistic regression analysis adjustment for MIF different genotypes and other potential risk factors such as age, sex and parental smoking indicated that the CC genotype is the only significant risk factor for the test (p = 0.02). We also noted that, by increasing the C‐allele representation within the gene [GC, CC], there was an increase in total leukocytic count (p = 0.09 and p = 0.001, respectively) that may reflect the bad prognostic impact of the polymorphic allele, although further studies are needed.

Conclusions

The results of the present study indicate that the MIF‐173G/C (rs755622) polymorphism is a risk factor for childhood ALL development with respect to both homozygous and combined polymorphic genotypes. In addition, the increased leukocytic count in synchronization with the increased representation of the polymorphic C‐allele may reflect its bad prognostic impact.  相似文献   

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Background

The aims of this study were to develop and validate a multiplex real‐time polymerase chain reaction (q‐PCR) assay of Helicobacter pylori in stool samples of healthy children. Additionally, we determined the prevalence of clarithromycin resistance and cagA gene in H. pylori‐positive samples.

Materials and methods

Archived stool samples from 188 children aged 6‐9 years and 272 samples of 92 infants aged 2‐18 months were tested for H. pylori antigens using enzyme immunoassay (EIA). A multiplex q‐PCR assay was designed to detect H. pylori 16S rRNA and urease and the human RNase P gene as an internal control. Kappa coefficient was calculated to assess the agreement between q‐PCR and EIA.

Results

Laboratory validation of the q‐PCR assay using quantitated H. pylori ATCC 43504 extracted DNA showed S‐shaped amplification curves for all genes; the limit of detection was 1 CFU/reaction. No cross‐reactivity with other bacterial pathogens was noted. Applying the multiplex q‐PCR to DNA extracted from fecal samples showed clear amplification curves for urease gene, but not for 16S rRNA. The prevalence of H. pylori infection was 50% (95% CI 43%‐57%) by q‐PCR (urease cycle threshold <44) vs 59% (95% CI 52%‐66%) by EIA. Kappa coefficient was .80 (P < .001) and .44 (P < .001) for children aged 6‐9 years and 2‐18 months, respectively. Sixteen samples were positive for cagA and three were positive for clarithromycin resistance mutation (A2143G) as confirmed by sequencing.

Conclusions

The developed q‐PCR can be used as a cotechnique to enhance the accuracy of H. pylori detection in epidemiological studies and in clinical settings.  相似文献   

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Background  

CJ9-gD is a novel dominant-negative recombinant herpes simplex virus type 1 (HSV-1) that is completely replication-defective, cannot establish detectable latent infection in vivo, and expresses high levels of the major HSV-1 antigen glycoprotein D immediately following infection. In the present study, CJ9-gD was evaluated as a vaccine against HSV-2 genital infection in guinea pigs.  相似文献   

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Background  

Long terminal repeat (LTR) retrotransposons are a class of mobile genetic element capable of autonomous transposition via an RNA intermediate. Their large size and proliferative ability make them important contributors to genome size evolution, especially in plants, where they can reach exceptionally high copy numbers and contribute substantially to variation in genome size even among closely related taxa. Using a phylogenetic approach, we characterize dynamics of proliferation events of Ty3/gypsy-like LTR retrotransposons that led to massive genomic expansion in three Helianthus (sunflower) species of ancient hybrid origin. The three hybrid species are independently derived from the same two parental species, offering a unique opportunity to explore patterns of retrotransposon proliferation in light of reticulate evolutionary events in this species group.  相似文献   

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Aim

Reconstruct the long‐term ecosystem dynamics of the region across an elevational gradient as they relate to climate and local controls. In particular, we (1) describe the dominant conifers' history; (2) assess changes in vegetation composition and distribution; and (3) note periods of abrupt change versus stability as means of better understanding vegetation responses to environmental variability.

Location

Greater Yellowstone Ecosystem (GYE; USA).

Time period

16.5 ka bp ‐present.

Major taxa studied

Juniperus, Picea, Abies, Pinus, Pseudotsuga.

Methods

The vegetation reconstruction was developed from 15 pollen records. Results were interpreted based on modern pollen–vegetation relationships estimated from a suite of regression‐based approaches.

Results

Calibrated pollen data suggest that late‐glacial vegetation, dominated by shrubs and Juniperus, lacks a modern counterpart in the area. Picea, Abies and Pinus expanded at 16 ka bp in association with postglacial warming and co‐occurred in mixed‐conifer parkland/forest after 12 ka bp . This association along with Pinus contorta forest, which was present after 9 ka bp , has persisted with little change at middle and high elevations to the present day. This stability contrasts with the dynamic history of plant communities at low elevations, where shifts between parkland, steppe and forest over the last 8,000 years were likely driven by variations in effective moisture and fire.

Main conclusions

The postglacial vegetation history of the GYE highlights the dynamic nature of mountain ecosystems and informs on their vulnerability to future climate change: (1) most of the conifers have been present in the area for >12,000 years and survived climate change by adjusting their elevational ranges; (2) some plant associations have exhibited stability over millennia as a result of nonclimatic controls; and (3) present‐day forest cover is elevationally more compressed than at any time in history, probably due to the legacy of the Medieval Climate Anomaly and the Little Ice Age.  相似文献   

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Background  

A close association between Sst I polymorphism in the 3' untranslated region of the apolipoproteinC3 (APOC3 ) gene and levels of plasma triglycerides (TG) had been reported by different investigators. Hypertriglyceridemia(HTG) is a known risk factor for coronary artery disease (CAD) in the context of Asian Indians. We conducted a study on the relationship between APOC3 SstI polymorphism (S1S1, S1S2 and S2S2 genotypes) and plasma TG levels in a group of 139 male healthy volunteers from Northern India.  相似文献   

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Abstract  

We present, simple approach for the accession of 1,2,3-triazole fused quinoline peptide analogues from 3-(azidomethyl)-2-chloroquinoline in a three-step mechanistic pathway. The UV–Visible absorbance plot shows dynamic interaction of parent triazole derivative with CT DNA as efficient DNA intercalator (K b = 4.6 × 10−4 M−1). Finally, the efficient DNA damage was observed on photo-irradiation at 360 nm in the presence of 2-(9H-Fluoren-9-ylmethoxycarbonylamino)-propionic acid 1-(2-chloro-quinolin-3-ylmethyl)-1H-[1,2,3]triazole-4-ylmethyl ester (6a).  相似文献   

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Introduction  

Previous studies have provided inconsistent results on whether variants in the MBL2 gene, coding for the complement-activating mannan-binding lectin (MBL) protein, associate with rheumatoid arthritis (RA). We re-evaluated this in context of the main environmental and genetic risk factors (smoking, HLA-DRB1 'shared epitope' (SE), PTPN22*620W), which predispose to rheumatoid factor (RF) and/or anti-citrullinated-protein antibody (ACPA)-positive RA.  相似文献   

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