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result(s) for
"Brichta, L."
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Mildly affected patients with spinal muscular atrophy are partially protected by an increased SMN2 copy number
2006
Spinal muscular atrophy (SMA) is a recessive neuromuscular disorder caused by loss of the SMN1 gene. The clinical distinction between SMA type I to IV reflects different age of onset and disease severity. SMN2, a nearly identical copy gene of SMN1, produces only 10% of full-length SMN RNA/protein and is an excellent target for a potential therapy. Several clinical trials with drugs that increase the SMN2 expression such as valproic acid and phenylbutyrate are in progress. Solid natural history data for SMA are crucial to enable a correlation between genotype and phenotype as well as the outcome of therapy. We provide genotypic and phenotypic data from 115 SMA patients with type IIIa (age of onset <3 years), type IIIb (age of onset >3 years) and rare type IV (onset >30 years). While 62% of type IIIa patients carry two or three SMN2 copies, 65% of type IIIb patients carry four or five SMN2 copies. Three type IV SMA patients had four and one had six SMN2 copies. Our data support the disease-modifying role of SMN2 leading to later onset and a better prognosis. A statistically significant correlation for > or =4 SMN2 copies with SMA type IIIb or a milder phenotype suggests that SMN2 copy number can be used as a clinical prognostic indicator in SMA patients. The additional case of a foetus with homozygous SMN1 deletion and postnatal measurement of five SMN2 copies illustrates the role of genotypic information in making informed decisions on the management and therapy of such patients.
Journal Article
High-Protein Nutritious Flatbreads and an Option for Gluten-Sensitive Individuals
by
Brichta, Jenny L.
,
Avena-Bustillos, Roberto J.
,
Kahlon, Talwinder S.
in
beets
,
bile acids
,
broccoli
2019
Whole grain quinoa and wheat, high-protein vegetable flatbreads were evaluated by tasters and a physical analysis was conducted. The objective was to produce nutritious, tasty gluten-free (quinoa) as well as gluten-containing (wheat) flatbreads. Flatbreads were Quinoa Peanut Oilcake Broccoli (QPCBROC), Wheat Peanut Oilcake Broccoli (WPCBROC), Quinoa Peanut Oilcake Beets (QPCBEET) and Wheat Peanut Oilcake Beets (WPCBEET). Peanut Oilcake would increase protein and add value to this farm byproduct. Bile acid binding broccoli and beets with cholesterol-lowering potential were used. Tasters preferred QPCBROC flatbreads for all sensory parameters. Acceptance of flatbreads was QPCBROC (83%), WPCBROC (70%), QPCBEET (78%) and WPCBEET (69%); these values were statistically similar. The objective of ≥25% protein content was exceeded by 5–8% and that of ≥70% acceptance was adequately achieved. These flatbreads were low in fat (5–6%) and contained essential minerals (4%) with only ≤1% added salt. Porosity and expansion data suggest that these flatbreads would take up relatively little shelf space. These flatbreads require only three ingredients and can be made in a household kitchen or by commercial production. These flatbreads offer a nutritious, tasty choice for all, and quinoa flatbreads offer an option for gluten-sensitive individuals.
Journal Article
The benzamide M344, a novel histone deacetylase inhibitor, significantly increases SMN2 RNA/protein levels in spinal muscular atrophy cells
by
Brichta, Lars
,
Hahnen, Eric
,
Riessland, Markus
in
Alternative Splicing
,
Atrophy
,
Biological and medical sciences
2006
Proximal spinal muscular atrophy (SMA) is a common autosomal recessively inherited neuromuscular disorder causing infant death in half of all patients. Homozygous loss of the survival motor neuron 1 (SMN1) gene causes SMA, whereas the number of the SMN2 copy genes modulates the severity of the disease. Due to a silent mutation within an exonic splicing enhancer, SMN2 mainly produces alternatively spliced transcripts lacking exon 7 and only approximately 10% of a full-length protein identical to SMN1. However, SMN2 represents a promising target for an SMA therapy. The correct splicing of SMN2 can be efficiently restored by over-expression of the splicing factor Htra2-beta1 as well as by exogenous factors like drugs that inhibit histone deacetylases (HDACs). Here we show that the novel benzamide M344, an HDAC inhibitor, up-regulates SMN2 protein expression in fibroblast cells derived from SMA patients up to 7-fold after 64 h of treatment. Moreover, M344 significantly raises the total number of gems/nucleus as well as the number of nuclei that contain gems. This is the strongest in vitro effect of a drug on the SMN protein level reported so far. The reversion of Delta7-SMN2 into FL-SMN2 transcripts as demonstrated by quantitative RT-PCR is most likely facilitated by elevated levels of Htra2-beta1. Investigations of the cytotoxicity of M344 using an MTT assay revealed toxic cell effects only at very high concentrations. In conclusion, M344 can be considered as highly potent HDAC inhibitor which is active at low doses and therefore represents a promising candidate for a causal therapy of SMA.
Journal Article
Some Rheological Properties of Latex from Parthenium argentatum Gray Compared with Latex from Hevea brasiliensis and Ficus elastica
2002
Latex was purified from Parthenium argentatum Gray (guayule), Hevea brasiliensis Müll. Arg. (the Brazilian or para rubber tree), and Ficus elastica Roxb. (the Indian rubber tree) in ammonium alginate at pH 10. The rheological properties of the different latices (rubber particle suspensions) were determined and compared using flow temperature ramps. Latex from all three species became more viscous with increasing rubber particle concentration and decreasing temperature. At any particular temperature and concentration, latex from F. elastica was by far the most viscous, whereas the H. brasiliensis latex was the least viscous. In addition, the tendency for the latex to coagulate increased with increasing temperature and increasing particle concentration. F. elastica latex was highly sensitive to temperature, H. brasiliensis latex was the least sensitive, and P. argentatum latex demonstrated intermediate properties. The underlying causes of these differences in latex rheology are not clear but may partially relate to the particle size (largest in F. elastica and smallest in H. brasiliensis), the particle size distribution, and/or to the considerable differences in the biochemical components of the monolayer biomembrane that surrounds the various rubber particles. Differences in the molecular weight of the rubber contained within the rubber particles seem less likely to play a role because the particles remain intact in this study.[PUBLICATION ABSTRACT]
Journal Article
Nonsense-mediated messenger RNA decay of survival motor neuron 1 causes spinal muscular atrophy
by
Brichta, Lars
,
Grellscheid, Sushma-Nagaraja
,
Wirth, Brunhilde
in
Atrophy
,
Biological and medical sciences
,
Biomedical and Life Sciences
2008
Autosomal recessive proximal spinal muscular atrophy (SMA) is a neurodegenerative disorder resulting from functional loss of
survival motor neuron 1
(
SMN1
). Homozygous absence of
SMN1
due to deletion or gene conversion accounts for about 96% of SMA cases. In the remaining 4%, subtle
SMN1
mutations are commonly identified. Here, we describe two novel intragenic
SMN1
mutations in three type I SMA individuals: a point mutation in exon 3 (c.469C > T) and a substitution in intron 4 (c.628-140A > G). In-vivo splicing assays demonstrated that the intronic substitution creates a novel splice donor site, culminating in aberrant splicing and insertion of 65 bp from intron 4 between exons 4 and 5 in
SMN1
transcripts (c.627_628ins65). Both mutations render
SMN1
transcripts susceptible to nonsense-mediated mRNA decay (NMD), resulting in mRNA degradation, insufficient SMN protein levels and development of an SMA phenotype. Treatment of patient cell lines with the translation inhibitors puromycin and emetine markedly increased the levels of mutant
SMN1
transcripts. A similar effect was observed after siRNA-mediated knockdown of UPF1, a factor essential for NMD. This study provides first evidence that NMD of
SMN1
transcripts is responsible for the molecular basis of disease in a subset of SMA patients.
Journal Article
Rates of evolutionary change of resident Escherichia coli O157:H7 differ within the same ecological niche
by
Bono, James L.
,
Clawson, Michael L.
,
Wells, James E.
in
Alleles
,
Animal Genetics and Genomics
,
Animals
2022
Background
Shiga toxin-producing
Escherichia coli
(STEC) O157:H7 is a pathogen known to reside in cattle feedlots. This retrospective study examined 181 STEC O157:H7 strains collected over 23 years from a closed-system feedlot. All strains were subjected to short-read sequencing, with a subset of 36 also subjected to long-read sequencing.
Results
Over 96% of the strains fell into four phylogenetically distinct clades. Clade membership was associated with multiple factors including
stx
composition and the alleles of a well-characterized polymorphism (
tir
255 T > A). Small plasmids (2.7 to 40 kb) were found to be primarily clade specific. Within each clade, chromosomal rearrangements were observed along with a core phageome and clade specific phages. Across both core and mobile elements of the genome, multiple SNP alleles were in complete linkage disequilibrium across all strains within specific clades. Clade evolutionary rates varied between 0.9 and 2.8 SNP/genome/year with two
tir
A allele clades having the lowest evolutionary rates. Investigation into possible causes of the differing rates was not conclusive but revealed a synonymous based mutation in the DNA polymerase III of the fastest evolving clade. Phylogenetic trees generated through our bioinformatic pipeline versus the NCBI’s pathogen detection project were similar, with the two
tir
A allele clades matching individual NCBI SNP clusters, and the two
tir
T allele clades assigned to multiple closely-related SNP clusters.
Conclusions
In one ecological niche, a diverse STEC O157:H7 population exhibited different rates of evolution that associated with SNP alleles in linkage disequilibrium in the core genome and mobile elements, including
tir
255 T > A.
Journal Article
Differences between predicted outer membrane proteins of genotype 1 and 2 Mannheimia haemolytica
2020
Background
Mannheimia haemolytica
strains isolated from North American cattle have been classified into two genotypes (1 and 2). Although members of both genotypes have been isolated from the upper and lower respiratory tracts of cattle with or without bovine respiratory disease (BRD), genotype 2 strains are much more frequently isolated from diseased lungs than genotype 1 strains. The mechanisms behind the increased association of genotype 2
M. haemolytica
with BRD are not fully understood. To address that, and to search for interventions against genotype 2
M. haemolytica
, complete, closed chromosome assemblies for 35 genotype 1 and 34 genotype 2 strains were generated and compared. Searches were conducted for the pan genome, core genes shared between the genotypes, and for genes specific to either genotype. Additionally, genes encoding outer membrane proteins (OMPs) specific to genotype 2
M. haemolytica
were identified, and the diversity of their protein isoforms was characterized with predominantly unassembled, short-read genomic sequences for up to 1075 additional strains.
Results
The pan genome of the 69 sequenced
M. haemolytica
strains consisted of 3111 genes, of which 1880 comprised a shared core between the genotypes. A core of 112 and 179 genes or gene variants were specific to genotype 1 and 2, respectively. Seven genes encoding predicted OMPs; a peptidase S6, a ligand-gated channel, an autotransporter outer membrane beta-barrel domain-containing protein (AOMB-BD-CP), a porin, and three different trimeric autotransporter adhesins were specific to genotype 2 as their genotype 1 homologs were either pseudogenes, or not detected. The AOMB-BD-CP gene, however, appeared to be truncated across all examined genotype 2 strains and to likely encode dysfunctional protein. Homologous gene sequences from additional
M. haemolytica
strains confirmed the specificity of the remaining six genotype 2 OMP genes and revealed they encoded low isoform diversity at the population level.
Conclusion
Genotype 2
M. haemolytica
possess genes encoding conserved OMPs not found intact in more commensally prone genotype 1 strains. Some of the genotype 2 specific genes identified in this study are likely to have important biological roles in the pathogenicity of genotype 2
M. haemolytica
, which is the primary bacterial cause of BRD.
Journal Article
Boys' Band on Vacation
1954
I am a member of the Tucson Boys' Band, which consists of about thirty boys between the ages of seven and fourteen.
Newspaper Article
Genomic signatures of Mannheimia haemolytica that associate with the lungs of cattle with respiratory disease, an integrative conjugative element, and antibiotic resistance genes
by
Bono, James L.
,
Clawson, Michael L.
,
DeDonder, Keith D.
in
Animal Genetics and Genomics
,
Animals
,
Anti-Bacterial Agents - pharmacology
2016
Background
Mannheimia haemolytica
typically resides in cattle as a commensal member of the upper respiratory tract microbiome. However, some strains can invade their lungs and cause respiratory disease and death, including those with multi-drug resistance. A nucleotide polymorphism typing system was developed for
M. haemolytica
from the genome sequences of 1133 North American isolates, and used to identify genetic differences between isolates from the lungs and upper respiratory tract of cattle with and without clinical signs of respiratory disease.
Results
A total of 26,081 nucleotide polymorphisms were characterized after quality control filtering of 48,403 putative polymorphisms. Phylogenetic analyses of nucleotide polymorphism genotypes split
M. haemolytica
into two major genotypes (1 and 2) that each were further divided into multiple subtypes. Multiple polymorphisms were identified with alleles that tagged genotypes 1 or 2, and their respective subtypes. Only genotype 2
M. haemolytica
associated with the lungs of diseased cattle and the sequence of a particular integrative and conjugative element (ICE). Additionally, isolates belonging to one subtype of genotype 2 (2b), had the majority of antibiotic resistance genes detected in this study, which were assorted into seven combinations that ranged from 1 to 12 resistance genes.
Conclusions
Typing of diverse
M. haemolytica
by nucleotide polymorphism genotypes successfully identified associations with diseased cattle lungs, ICE sequence, and antibiotic resistance genes. Management of cattle by their carriage of
M. haemolytica
could be an effective intervention strategy to reduce the prevalence of respiratory disease and supplemental needs for antibiotic treatments in North American herds.
Journal Article