Development of genomic simple sequence repeat markers in opium poppy by next-generation sequencing

Opium poppy (Papaver somniferum L.) is an important pharmaceutical crop with very few genetic marker resources. To expand these resources, we sequenced genomic DNA using pyrosequencing technology and examined the DNA sequences for simple sequence repeats (SSRs). A total of 1,244,412 sequence reads were obtained covering 474 Mb. Approximately half of the reads (52 %) were assembled into 166,724 contigs representing 105 Mb of the opium poppy genome. A total of 23,283 non-redundant SSRs were identified in 18,944 contigs (11.3 % of total contigs). Trinucleotide and tetranucleotide repeats were the most abundant SSR repeats, accounting for 49.0 and 27.9 % of all SSRs, respectively. The AAG/TTC repeat was the most abundant trinucleotide repeat, representing 19.7 % of trinucleotide repeats. Other SSR repeat types were AT-rich. A total of 23,126 primer pairs (98.7 % of total SSRs) were designed to amplify SSRs. Fifty-three genomic SSR markers were tested in 37 opium poppy accessions and seven Papaver species for determination of polymorphism and transferability. Intraspecific polymorphism information content (PIC) values of the genomic SSR markers were intermediate, with an average 0.17, while the interspecific average PIC value was slightly higher, 0.19. All markers showed at least 88 % transferability among related species. This study increases sequence coverage of the opium poppy genome by sevenfold and the number of opium poppy-specific SSR markers by sixfold. This is the first report of the development of genomic SSR markers in opium poppy, and the genomic SSR markers developed in this study will be useful in diversity, identification, mapping and breeding studies in opium poppy.     

Nontuberculous mycobacteria isolated from pulmonary specimens between 2004 and 2009: causative agent or not?

Nontuberculous mycobacteria were identified from 45891 samples of 19553 patients with a prediagnosis of pulmonary tuberculosis between November 2004 and January 2009. Among 10041 (21.9%) culture positive samples, 208 (2.1%) pulmonary samples recovered from 77 individual patients were differentiated as mycobacteria other than tuberculosis (MOTT). Proportion of mycobacteria evaluated as causative agent for clinical infection were found as 0.16% (n = 31), mostly M. avium complex, M. abscessus and M. kansasii. Additionally, M. fortuitum-peregrinum complex, M. simiae, M. szulgai / intermedium and M. scrofulaceum were found as causative agent in 2, 2, 2 and 1 patient, respectively. Identification of infections caused by environmental or opportunistic pathogen mycobacteria is required in rapid and accurate diagnosis, infection control and treatment planning of infections caused by M. tuberculosis complex and/or MOTT.     

Phagocytosis of degenerating myelin in transected feline optic nerve: an immunohistochemical study

The phagocytic activity of neuroglial cells in adult feline degenerating optic nerve was investigated by immunocytochemistry at both light and electron microscopy levels. Degeneration was initiated by unilateral eye enucleation and the segment distal to the transection showing true Wallerian degeneration was examined. Following enucleation, twelve adult domestic cats were examined over a period of seven to 215 days. All cases showed slow clearance of myelin debris and absence of proliferating monocytes throughout the post-enucleation period. All phagocytic cells present were neuroglial cells, and many of these cells expressed oligodendroglial antigens. These findings demonstrate the persistence of an active population of oligodendrocytes that might play an additional functional role during Wallerian degeneration of feline optic nerve.     

Antibiotic susceptibility patterns of respiratory isolates of Staphylococcus aureus in a Turkish university hospital

A total of 391 respiratory isolates of Staphylococcus aureus in Sivas (Turkey) were studied between January 1999-2002. The organisms were cultured from the following specimens: throat (43%), sputum (28%), transtracheal/endotracheal aspirates (27%), and bronchial lavage (2%). The isolates were tested against 11 different antibiotics by a disk diffusion method or standardized microdilution technique. Methicillin-resistant isolates constituted 76.9% of all isolates. Most of the methicillin-resistant isolates (95.1%) were isolated from inpatients. The rate of methicillin-resistant isolates in throat, sputum, and tracheal aspirates was 17.2%, 60.1%, and 68.9%, respectively. The resistance of methicillin-resistant isolates in throat to teicoplanin was 3.4%. The methicillin-sensitive isolates were susceptible to most agents tested, while most methicillin-resistant isolates were resistant to these agents. Overall resistance to erythromycin was 61.9%, tetracycline 56.6%, gentamicin 50.7%, ofloxacin 42.0%, rifampin 40.8%, clindamycin 38.9%, chloramphenicol 19.0%, co-trimoxazole 10.2%, and vancomycin 0%.     

AT excursion: a new approach to predict replication origins in viral genomes by locating AT-rich regions

Background  

Replication origins are considered important sites for understanding the molecular mechanisms involved in DNA replication. Many computational methods have been developed for predicting their locations in archaeal, bacterial and eukaryotic genomes. However, a prediction method designed for a particular kind of genomes might not work well for another. In this paper, we propose the AT excursion method, which is a score-based approach, to quantify local AT abundance in genomic sequences and use the identified high scoring segments for predicting replication origins. This method has the advantages of requiring no preset window size and having rigorous criteria to evaluate statistical significance of high scoring segments.     

Permeation of ions across the potassium channel: brownian dynamics studies

The physical mechanisms underlying the transport of ions across a model potassium channel are described. The shape of the model channel corresponds closely to that deduced from crystallography. From electrostatic calculations, we show that an ion permeating the channel, in the absence of any residual charges, encounters an insurmountable energy barrier arising from induced surface charges. Carbonyl groups along the selectivity filter, helix dipoles near the oval chamber, and mouth dipoles near the channel entrances together transform the energy barrier into a deep energy well. Two ions are attracted to this well, and their presence in the channel permits ions to diffuse across it under the influence of an electric field. Using Brownian dynamics simulations, we determine the magnitude of currents flowing across the channel under various conditions. The conductance increases with increasing dipole strength and reaches its maximum rapidly; a further increase in dipole strength causes a steady decrease in the channel conductance. The current also decreases systematically when the effective dielectric constant of the channel is lowered. The conductance with the optimal choice of dipoles reproduces the experimental value when the dielectric constant of the channel is assumed to be 60. The current-voltage relationship obtained with symmetrical solutions is linear when the applied potential is less than approximately 100 mV but deviates from Ohm's law at a higher applied potential. The reversal potentials obtained with asymmetrical solutions are in agreement with those predicted by the Nernst equation. The conductance exhibits the saturation property observed experimentally. We discuss the implications of these findings for the transport of ions across the potassium channels and membrane channels in general.     

Biological ancestries, kinship connections, and projected identities in four central Anatolian settlements: insights from culturally contextualized genetic anthropology

Previous population genetics studies in Turkey failed to delineate recent historical and social factors that shaped Anatolian cultural and genetic diversity at the local level. To address this shortcoming, we conducted focused ethnohistorical fieldwork and screened biological samples collected from the Yuksekyer region for mitochondrial, Y chromosome, and autosomal markers and then analyzed the data within an ethnohistorical context. Our results revealed that, at the village level, paternal genetic diversity is structured among settlements, whereas maternal genetic diversity is distributed more homogenously, reflecting the strong patrilineal cultural traditions that transcend larger ethnic and religious structures. Local ancestries and origin myths, rather than ethnic or religious affiliations, delineate the social boundaries and projected identities among the villages. Therefore, we conclude that broad, ethnicity-based sampling is inadequate to capture the genetic signatures of recent social and historical dynamics, which have had a profound influence on contemporary genetic and cultural regional diversity.     

Imaging Breast Density: Established and Emerging Modalities

Mammographic density has been proven as an independent risk factor for breast cancer. Women with dense breast tissue visible on a mammogram have a much higher cancer risk than women with little density. A great research effort has been devoted to incorporate breast density into risk prediction models to better estimate each individual’s cancer risk. In recent years, the passage of breast density notification legislation in many states in USA requires that every mammography report should provide information regarding the patient’s breast density. Accurate definition and measurement of breast density are thus important, which may allow all the potential clinical applications of breast density to be implemented. Because the two-dimensional mammography-based measurement is subject to tissue overlapping and thus not able to provide volumetric information, there is an urgent need to develop reliable quantitative measurements of breast density. Various new imaging technologies are being developed. Among these new modalities, volumetric mammographic density methods and three-dimensional magnetic resonance imaging are the most well studied. Besides, emerging modalities, including different x-ray–based, optical imaging, and ultrasound-based methods, have also been investigated. All these modalities may either overcome some fundamental problems related to mammographic density or provide additional density and/or compositional information. The present review article aimed to summarize the current established and emerging imaging techniques for the measurement of breast density and the evidence of the clinical use of these density methods from the literature.     

A new metabolomics analysis technique: steady-state metabolic network dynamics analysis

With the recent advances in experimental technologies, such as gas chromatography and mass spectrometry, the number of metabolites that can be measured in biofluids of individuals has markedly increased. Given a set of such measurements, a very common task encountered by biologists is to identify the metabolic mechanisms that lead to changes in the concentrations of given metabolites and interpret the metabolic consequences of the observed changes in terms of physiological problems, nutritional deficiencies, or diseases. In this paper, we present the steady-state metabolic network dynamics analysis (SMDA) approach in detail, together with its application in a cystic fibrosis study. We also present a computational performance evaluation of the SMDA tool against a mammalian metabolic network database. The query output space of the SMDA tool is exponentially large in the number of reactions of the network. However, (i) larger numbers of observations exponentially reduce the output size, and (ii) exploratory search and browsing of the query output space is provided to allow users to search for what they are looking for.