Publications by authors named "Russell Malmberg"

provide an optimal system for deciphering the host-microbiome interactions at various levels. We analyzed the pitcher microbiomes and metatranscriptomes of the parental species, and F1 and F2 generations from the mapping population ( X ) utilizing high-throughput sequencing methods. This study aimed to examine the host influences on the microbiome structure and function and to identify the key microbiome traits.

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The study of carnivorous plants can afford insight into their unique evolutionary adaptations and their interactions with prokaryotic and eukaryotic species. For (pitcher plants), we identified 64 quantitative trait loci (QTL) for insect-capture traits of the pitchers, providing the genetic basis for differences between the pitfall and lobster-trap strategies of insect capture. The linkage map developed here is based upon the F2 of a cross between and ; we mapped 437 single nucleotide polymorphism and simple sequence repeat markers.

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miRNAs are involved in many critical cellular activities through binding to their mRNA targets, e.g. in cell proliferation, differentiation, death, growth control, and developmental timing.

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Background: Research on orphan crops is often hindered by a lack of genomic resources. With the advent of affordable sequencing technologies, genotyping an entire genome or, for large-genome species, a representative fraction of the genome has become feasible for any crop. Nevertheless, most genotyping-by-sequencing (GBS) methods are geared towards obtaining large numbers of markers at low sequence depth, which excludes their application in heterozygous individuals.

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We describe restriction site associated RNA sequencing (RARseq), an RNAseq-based genotype by sequencing (GBS) method. It includes the construction of RNAseq libraries from double stranded cDNA digested with selected restriction enzymes. To test this, we constructed six single- and six-dual-digested RARseq libraries from six F2 pitcher plant individuals and sequenced them on a half of a Miseq run.

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Premise Of The Study: The sunflower genus Helianthus has long been recognized as economically significant, containing species of agricultural and horticultural importance. Additionally, this genus displays a large range of phenotypic and genetic variation, making Helianthus a useful system for studying evolutionary and ecological processes. Here we present the most robust Helianthus phylogeny to date, laying the foundation for future studies of this genus.

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Motivation: Given the importance of non-coding RNAs to cellular regulatory functions, it would be highly desirable to have accurate computational prediction of RNA 3D structure, a task which remains challenging. Even for a short RNA sequence, the space of tertiary conformations is immense; existing methods to identify native-like conformations mostly resort to random sampling of conformations to achieve computational feasibility. However, native conformations may not be examined and prediction accuracy may be compromised due to sampling.

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The North American carnivorous pitcher plant genus Sarracenia (Sarraceniaceae) is a relatively young clade (<3 million years ago) displaying a wide range of morphological diversity in complex trapping structures. This recently radiated group is a promising system to examine the structural evolution and diversification of carnivorous plants; however, little is known regarding evolutionary relationships within the genus. Previous attempts at resolving the phylogeny have been unsuccessful, most likely due to few parsimony-informative sites compounded by incomplete lineage sorting.

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Unlabelled: RNA secondary structure ensembles define probability distributions for alternative equilibrium secondary structures of an RNA sequence. Shannon's entropy is a measure for the amount of diversity present in any ensemble. In this work, Shannon's entropy of the SCFG ensemble on an RNA sequence is derived and implemented in polynomial time for both structurally ambiguous and unambiguous grammars.

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Unlabelled: TRFolder-W is a web server capable of predicting core structures of telomerase RNA (TR) in yeast genomes. TRFolder is a command-line Python toolkit for TR-specific structure prediction. We developed a web-version built on the django web framework, leveraging the work done previously, to include enhancements to increase flexibility of usage.

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Introduced species frequently show geographic differentiation, and when differentiation mirrors the ancestral range, it is often taken as evidence of adaptive evolution. The mouse-ear cress (Arabidopsis thaliana) was introduced to North America from Eurasia 150-200 years ago, providing an opportunity to study parallel adaptation in a genetic model organism. Here, we test for clinal variation in flowering time using 199 North American (NA) accessions of A.

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Background: RNA secondary structure plays a scaffolding role for RNA tertiary conformation. Accurate secondary structure prediction can not only identify double-stranded helices and single stranded-loops but also help provide information for potential tertiary interaction motifs critical to the 3D conformation. The average accuracy in ab initio prediction remains 70%; performance improvement has only been limited to short RNA sequences.

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Background: The computational identification of RNAs in genomic sequences requires the identification of signals of RNA sequences. Shannon base pairing entropy is an indicator for RNA secondary structure fold certainty in detection of structural, non-coding RNAs (ncRNAs). Under the Boltzmann ensemble of secondary structures, the probability of a base pair is estimated from its frequency across all the alternative equilibrium structures.

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The goal of this work was to study mutational patterns in the evolution of RNA secondary structure. We analyzed bacterial tmRNA, RNaseP and eukaryotic telomerase RNA secondary structures, mapping structural variability onto phylogenetic trees constructed primarily from rRNA sequences. We found that secondary structures evolve both by whole stem insertion/deletion, and by mutations that create or disrupt stem base pairing.

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Sarracenia species (pitcher plants) are carnivorous plants which obtain a portion of their nutrients from insects captured in the pitchers. To investigate these plants, we sequenced the transcriptome of two species, Sarracenia psittacina and Sarracenia purpurea, using Roche 454 pyrosequencing technology. We obtained 46 275 and 36 681 contigs by de novo assembly methods for S.

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Secondary structure remains the most exploitable feature for noncoding RNA (ncRNA) gene finding in genomes. However, methods based on secondary structure prediction may generate superfluous amount of candidates for validation and have yet to deliver the desired performance that can complement experimental efforts in ncRNA gene finding. This paper investigates a novel method, unpaired structural entropy (USE) as a measurement for the structure fold stability of ncRNAs.

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The identification of Telomerase RNAs (TRs) has been difficult owing to their rapid evolutionary divergence. The common core structure found in all known TRs contains a pseudoknot and a triple helix, which are beyond the capability of existing RNA-structure-profiling techniques. We describe a novel approach to predict the structure of key TR features and to aid the identification of TRs in genomes, using a program we developed, TRFolder.

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The study of RNA sequence structural alignments has become an important part of characterising noncoding RNAs. We developed RNApasta, a Java program with a graphical interface, to perform analysis and editing of RNA alignments. RNApasta can be used to generate statistics for modelling RNAs and to develop homogeneous subsets of alignments that contain variability.

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Sarracenia species (pitcher plants) are carnivorous plants which obtain a portion of their nutrients from insects captured in the pitchers. Sarracenia species naturally hybridize with each other, and hybrid swarms have been identified. A number of the taxa within the genus are considered endangered.

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RNATOPS-W is a web server to search sequences for RNA secondary structures including pseudoknots. The server accepts an annotated RNA multiple structural alignment as a structural profile and genomic or other sequences to search. It is built upon RNATOPS, a command line C++ software package for the same purpose, in which filters to speed up search are manually selected.

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Article Synopsis
  • Scientists are trying to find special strands of RNA called non-coding RNAs (ncRNAs) by looking at their shapes instead of their sequences.
  • They created a new program called RNATOPS that helps quickly and accurately search for these RNA shapes, especially complicated ones called pseudoknots.
  • The program uses smart techniques to narrow down the areas in the RNA sequences it needs to check, making the search process much faster while still being correct.*
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Stochastic Context-Free Grammars (SCFG) has been shown to be effective in modelling RNA secondary structure for searches. Our previous work (Cai et al., 2003) in Stochastic Parallel Communicating Grammar Systems (SPCGS) has extended SCFG to model RNA pseudoknots.

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The prediction of RNA secondary structure including pseudoknots remains a challenge due to the intractable computation of the sequence conformation from nucleotide interactions under free energy models. Optimal algorithms often assume a restricted class for the predicted RNA structures and yet still require a high-degree polynomial time complexity, which is too expensive to use. Heuristic methods may yield time-efficient algorithms but they do not guarantee optimality of the predicted structure.

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Background: Septins are cytoskeletal GTPase proteins first discovered in the fungus Saccharomyces cerevisiae where they organize the septum and link nuclear division with cell division. More recently septins have been found in animals where they are important in processes ranging from actin and microtubule organization to embryonic patterning and where defects in septins have been implicated in human disease. Previous studies suggested that many animal septins fell into independent evolutionary groups, confounding cross-kingdom comparison.

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