Winter Host Plant Specialization in a Host-Alternating Aphid

The host alternating aphid, Rhopalosiphum padi (L.), feeds in summer on several different species of grasses but is monophagous on its winter host, Prunus padus L. The monophagy on P. padus could be a result of the restricted host range of the several different generations colonizing, or feeding, on this host during autumn–winter–spring. This study shows that the winter host plant specificity of R. padi is controlled mainly by the preference of the females remigrating (gynoparae) to the winter host, P. padus, in autumn. The other generations living on the winter host, i.e., sexual females, males, and spring generations, all accept a broader range of winter hosts. One alternative host plant, Prunus spinosa L., could be utilized by all generations associated with the winter host, except for the females remigrating at autumn.     

Substantial molecular variation and low genetic structure in Kenya’s black rhinoceros: implications for conservation

Kenya’s black rhinoceros population declined by more than 98% from 20,000 individuals in the 1970s to around 400 individuals in 1990 due to the effects of poaching, at which time the surviving individuals were isolated in a series of demographically inviable subpopulations. An initial management exercise translocated the survivors into four high security sanctuaries to control poaching and enhance breeding, and this measure successfully arrested the decline. Subsequently, new sanctuaries were established and the metapopulation size reached 650 animals by 2008. However, translocations and the current management strategy that partitions the metapopulation into ‘montane’ and ‘lowland’ rhinoceros may have substantial consequences at the population level and their impact on population genetic diversity has not been investigated. In this study, 12 of the 16 extant subpopulations were analysed using 408 bp of mitochondrial control region sequence (n = 170) and nine microsatellite loci (n = 145). Both markers detected moderate to high genetic diversity (h = 0.78 ± 0.027, n = 170; H_O = 0.70 ± 0.087, n = 145) consistent with previous studies on Diceros bicornis michaeli. However, mtDNA and nDNA diversity varied substantially between subpopulations. The results suggest that the Masai Mara is more differentiated, inbred and isolated than other subpopulations. It also suggests that there are neither distinct montane and lowland groups nor other detectable historical barriers to gene flow. Instead the large majority of genetic diversity was partitioned at the level of individuals; highlighting the need to conserve as many individuals as possible. Future translocations should consider the genetic profile of individuals and the demographic history of both the donor and recipient subpopulations.     

DOME/GALT type adenocarcimoma of the colon: a case report,literature review and a unified phenotypic categorization

Several types of colorectal cancers are associated with a prominent lymphoid component, which is considered a positive prognostic factor.We report a case of a dome-type carcinoma of the cecum in a 57 year old female.The sessile, non-polypoid lesion histologically consisted of a tubulovillous adenoma with low-grade dysplasia.The submucosal invasive component showed low-grade architectural features that included cystically dilated glands containing eosinohilic debris. Immunohistochemical studies displayed retention of the four mistmach repair proteins, consistent with a stable phenotype. After 3 years, the patient remains free of recurrence.A literature review highlighted striking similarities between dome-type carcinoma and the gut-associated lymphoid tissue carcinoma, the two sharing an intimate association with the gut associated lymphoid tissue.The two variants might therefore be grouped into a unified category.     

Improvement of Brazilian bioethanol production – Challenges and perspectives on the identification and genetic modification of new strains of Saccharomyces cerevisiae yeasts isolated during ethanol process

In Brazil, bioethanol is produced by sucrose fermentation from sugarcane by Saccharomyces cerevisiae in a fed-batch process that uses high density of yeast cells (15–25 % of wet weight/v) and high sugar concentration (18–22 % of total sugars). Several research efforts have been employed to improve the efficiency of this process through the isolation of yeasts better adapted to the Brazilian fermentation conditions. Two important wild strains named CAT-1 and PE-2 were isolated during the fermentation process and were responsible for almost 60 % of the total ethanol production in Brazil. However, in the last decade the fermentative substrate composition was much modified, since new sugar cane crops were developed, the use of molasses instead of sugar cane juice increase and with the prohibition of burning of sugarcane prior harvest. As consequence, these previously isolated strains are being replaced by new wild yeasts in most of ethanol plants. In this new scenario the isolation of novel better adapted yeasts with improved fermentative characteristics is still a big challenge. Here, we discuss the main aspects of Brazilian ethanol production and the efforts for the selection, characterization and genetic modifications of new strains with important phenotypic traits such as thermotolerance.     

Characterization of water and wildlife strains as a subgroup of Campylobacter jejuni using DNA microarrays

Campylobacter jejuni is the leading cause of human bacterial gastroenteritis worldwide, but source attribution of the organism is difficult. Previously, DNA microarrays were used to investigate isolate source, which suggested a non‐livestock source of infection. In this study we analysed the genome content of 162 clinical, livestock and water and wildlife (WW) associated isolates combined with the previous study. Isolates were grouped by genotypes into nine clusters (C1 to C9). Multilocus sequence typing (MLST) data demonstrated that livestock associated clonal complexes dominated clusters C1–C6. The majority of WW isolates were present in the C9 cluster. Analysis of previously reported genomic variable regions demonstrated that these regions were linked to specific clusters. Two novel variable regions were identified. A six gene multiplex PCR (mPCR) assay, designed to effectively differentiated strains into clusters, was validated with 30 isolates. A further five WW isolates were tested by mPCR and were assigned to the C7‐C9 group of clusters. The predictive mPCR test could be used to indicate if a clinical case has come from domesticated or WW sources. Our findings provide further evidence that WW C. jejuni subtypes show niche adaptation and may be important in causing human infection.     

Mutations in the catalytic domain of human coagulation factor IX: rapid characterization by direct genomic sequencing of DNA fragments displaying an altered melting behavior

Deficiency in coagulation factor IX, a plasma glycoprotein constituent of the clotting cascade, results in hemophilia B, an inherited recessive X-linked bleeding disorder. Some affected individuals, referred to as antigen positive or CRM+, express an inactive factor IX gene product at normal levels and are expected to have natural mutations altering domains of the molecule that are critical for its correct function. The serine protease catalytic domain of activated factor IX, encoded by exons VII and VIII of the gene, is a possible target for such mutations. We designed a strategy allowing rapid analysis of this region through enzymatic amplification of genomic DNA, analysis of the amplification products by denaturing gradient gel electrophoresis, and direct sequencing of the fragments displaying an altered melting behavior. This procedure permitted us to characterize two previously undescribed mutations. Factor IX Angers is a G-to-A substitution generating an Arg in place of a Gly at amino acid 396 of the mature factor IX protein. Factor IX Bordeaux is an A-to-T substitution introducing a nonsense codon in place of the normal codon for Lys at position 411. Moreover, the already described factor IX Vancouver defect was found in three apparently independent families. These results provide further insight into the molecular heterogeneity of hemophilia B. In addition, we demonstrate the usefulness of this rapid screening procedure, which has broad applications in human genetics and can be used as an alternative to RFLP analysis in carrier detection or prenatal diagnosis studies.     

Comparison of the Bacterial Composition and Structure in Symptomatic and Asymptomatic Endodontic Infections Associated with Root-Filled Teeth Using Pyrosequencing

Residual microorganisms and/or re-infections are a major cause for root canal therapy failure. Understanding of the bacterial content could improve treatment protocols. Fifty samples from 25 symptomatic and 25 asymptomatic previously root-filled teeth were collected from Sudanese patients with periradicular lesions. Amplified 16S rRNA gene (V1-V2) variable regions were subjected to pyrosequencing (FLX 454) to determine the bacterial profile. Obtained quality-controlled sequences from forty samples were classified into 741 operational taxonomic units (OTUs) at 3% dissimilarity, 525 at 5% dissimilarity and 297 at 10% dissimilarity, approximately corresponding to species-, genus- and class levels. The most abundant phyla were: Firmicutes (29.9%), Proteobacteria (26.1%), Actinobacteria (22.72%), Bacteroidetes (13.31%) and Fusobacteria (4.55%). Symptomatic patients had more Firmicutes and Fusobacteria than asymptomatic patients, while asymptomatic patients showed more Proteobacteria and Actinobacteria. Interaction of disease status and age was observed by two-way ANOSIM. Canonical correspondence analysis for age, tooth restoration and disease status showed a correlation of disease status with the composition and prevalence of different members of the microbial community. The pyrosequencing analysis revealed a distinctly higher diversity of the microbiota compared to earlier reports. The comparison of symptomatic and asymptomatic patients showed a clear association of the composition of the bacterial community with the presence and absence of symptoms in conjunction with the patients’ age.