Delayed Radial Nerve Injury from a Brachial Artery Pseudoaneurysm Following a Four-Part Proximal Humerus Fracture: A Case Report and Literature Review.

CASE: Following a 4-part proximal humerus fracture at the level of the surgical neck, an 84-year-old woman presented with delayed radial nerve deficits secondary to a brachial artery pseudoaneurysm. She underwent emergent repair of the vessel and reverse total shoulder arthroplasty. The deficit remained present at 1-year follow-up and is unlikely to improve. CONCLUSIONS: Brachial artery pseudoaneurysms can occur following humeral fractures. Fractures at this location can lead to the unique complication of a proximal pseudoaneurysm that compresses the radial nerve. It should be considered a possible limb-threatening complication in fractures managed conservatively as well as surgical candidates.

Infection deflection: hosts control parasite location with behaviour to improve tolerance.

Anti-parasite behaviour can reduce parasitic infections, but little is known about how such behaviours affect infection location within the host's body and whether parasite distribution ultimately affects tolerance of infection. To assess these questions, we exposed both anaesthetized (no behaviour) and non-anaesthetized Hyla femoralis tadpoles to plagiorchiid cercariae (larval trematodes), and quantified resistance, tolerance (relationship between mass change and infection intensity) and encystment location. Non-anaesthetized tadpoles had significantly more infections in their tail region than anaesthetized tadpoles, which had the majority of their infections in the head. This pattern indicates that parasites preferred to infect the head, but that hosts shunted infections to the tail when possible. Furthermore, there was a significant effect of encystment location on tolerance, with head-infected tadpoles having poorer tolerance to infection than tail-infected tadpoles. Variance partitioning suggests that, among infected tadpoles, behaviour contributed more to tolerance than resistance. These results suggest that, in addition to using behaviour to resist parasites, H. femoralis tadpoles also use behaviour to enhance infection tolerance by deflecting infections posteriorly, away from their vital sensory organs. These findings highlight the need to assess how widespread and important behaviour is to the tolerance of infections.

Loss of trematode parthenitae in Planorbella trivolvis (Mollusca: Gastropoda).

Infection by trematode parthenitae (larval, asexual trematodes) has severe consequences for molluscan hosts, resulting in cessation of reproduction and early mortality. Here we present evidence that the freshwater snail Planorbella trivolvis can lose infections by trematode parthenitae. Of 8 P. trivolvis infected by reniferin parthenitae, 6 died within 2 wk, whereas the remaining 2 snails lost their infections within 82 days after initial examination. This phenomenon might suggest that molluscs can resist established trematode infections (i.e., "self-cure") or at least out-survive some trematode parthenitae.

Role of fatty acids and polyphenols in inflammatory gene transcription and their impact on obesity, metabolic syndrome and diabetes.

Obesity, metabolic syndrome and diabetes represent multi-factorial conditions resulting from improper balances of hormones and gene expression. In addition, these conditions have a strong inflammatory component that can potentially be impacted by the diet. The purpose of this review is to discuss the molecular targets that can be addressed by anti-inflammatory nutrition. These molecular targets range from reduction of pro-inflammatory eicosanoids that can alter hormonal signaling cascades to the modulation of the innate immune system, via toll-like receptors and gene transcription factors. Working knowledge of the impact of nutrients, especially dietary fatty acids and polyphenols, on these various molecular targets makes it possible to develop a general outline of an anti-inflammatory diet that offers a unique, non-pharmacological approach for treating obesity, metabolic syndrome and diabetes.

A new species of myxosporean (Sphaeromyxidae), a parasite of lined seahorses, Hippocampus erectus, from the Gulf of Mexico.

Sphaeromyxa cannolii sp. n. is described from the bile ducts of aquaria-maintained lined seahorses (Hippocampus erectus) from the Gulf of Mexico. Spores of the new species are linear, 17-18 µm long and 5-6 µm wide, with flattened tips; polar capsules measure 4 × 3 µm. Routine necropsies of H. erectus following planned death revealed liver inflammation, bile duct obstruction, bile accumulation, and myxozoan parasites in the bile ducts of 11 of 40 animals sampled (27.5%). The presence of S. cannolii in an aquaculture setting should prompt keepers to carefully quarantine new animals and exclude annelid fauna, a potential intermediate host of myxozoans.

Chloroplast mutations induced by 9-aminoacridine hydrochloride are independent of the plastome mutator in Oenothera.

Oenothera plants homozygous for the recessive plastome mutator allele ( pm) show chloroplast DNA (cpDNA) mutation frequencies that are about 1,000-fold higher than spontaneous levels. The pm-encoded gene product has been hypothesized to have a function in cpDNA replication, repair and/or mutation avoidance. Previous chemical mutagenesis experiments with the alkylating agent nitroso-methyl urea (NMU) showed a synergistic effect of NMU on the induction of mutations in the pm line, suggesting an interaction between the pm-encoded gene product and one of the repair systems that corrects alkylation damage. The goal of the experiments described here was to examine whether the pm activity extends to the repair of damage caused by non-alkylating mutagens. To this end, the intercalating mutagen, 9-aminoacridine hydrochloride (9AA) was tested for synergism with the plastome mutator. A statistical analysis of the data reported here indicates that the pm-encoded gene product is not involved in the repair of the 9AA-induced mutations. However, the recovery of chlorotic sectors in plants derived from the mutagenized seeds shows that 9AA can act as a mutagen of the chloroplast genome.

Complete nucleotide sequence of the Oenothera elata plastid chromosome, representing plastome I of the five distinguishable euoenothera plastomes.

We describe the 159,443-bp [corrected] sequence of the plastid chromosome of Oenothera elata (evening primrose). The Oe. elata plastid chromosome represents type I of the five genetically distinguishable basic plastomes found in the subsection Euoenothera. The genus Oenothera provides an ideal system in which to address fundamental questions regarding the functional integration of the compartmentalised genetic system characteristic of the eukaryotic cell. Its highly developed taxonomy and genetics, together with a favourable combination of features in its genetic structure (interspecific fertility, stable heterozygous progeny, biparental transmission of organelles, and the phenomenon of complex heterozygosity), allow facile exchanges of nuclei, plastids and mitochondria, as well as individual chromosome pairs, between species. The resulting hybrids or cybrids are usually viable and fertile, but can display various forms of developmental disturbance.

Plastome mutator-induced alterations arise in Oenothera chloroplast DNA through template slippage.

The plastome mutator of Oenothera hookeri strain Johansen causes deletions and duplications at target sites defined by direct repeats in the plastid genome. Previous studies characterized the mutations long after they had occurred and could not discriminate between the possibilities that the plastome mutator acted through unequal homologous recombination or template slippage. From the known hotspots, the rRNA spacer in the large inverted repeat was chosen for this study because it contains both direct and indirect repeats. Identical deletions were recovered from independently derived plants; the altered regions were always flanked by direct repeats. The regions in which the deletions occurred have the potential to form secondary structures that would stabilize the intervening sequence. Of the two affected regions, the one with the stronger potential secondary structure was altered more frequently. Because no duplication products or inversions were recovered, it is proposed that the plastome mutator acts through template slippage rather than through a recombination mechanism.

Characterization of primary lesions caused by the plastome mutator of Oenothera.

Oenothera plants homozygous for a recessive allele at the plastome mutator (pm) locus show non-Mendelian mutation frequencies that are 1000-fold higher than spontaneous levels. Characterization of RFLP sites in a collection of mutants indicates that insertion-deletion hot spots in the pm lines are defined by tandem direct repeats, implicating replication slippage or misalignment during recombination. Several sites known to contain very short direct repeats were examined, and all were found to have been targeted in one or more plants of the mutant collection. To determine if replication slippage was occurring, two oligo-A stretches in non-coding DNA were examined, and 3 of 12 plants were found to have an additional adenine in a 13-base track. To search for other mutations that would not be visible as restriction fragment length polymorphisms, PCR-amplification products of the psbB gene were digested with a restriction endonuclease, denatured, and examined for single-strand conformational polymorphisms. Among 21 mutants, one 4-bp insertion and one point mutation were identified in psbB. The discovery that the plastome mutator can cause base substitutions as well as repeat-mediated insertions and deletions points to a likely defect in a component of the cpDNA replication machinery.

Proliferation of direct repeats near the Oenothera chloroplast DNA origin of replication.

The spacer between the 16S and 23S rRNA genes of the chloroplast DNA has been implicated as an origin of replication in several species of plants. In the evening primrose, Oenothera, this site was found to vary greatly in size, with plastid genomes (plastomes) being readily distinguished. To determine whether plastome "strength" in transmission could be correlated with variation at oriB, the 16S rRNA-trnI spacer was sequenced from five plastomes. The size variation was found to be due to differential amplification (and deletion) of combinations of sequences belonging to seven families of direct repeats. From these comparisons, one short series of direct repeats and one region capable of forming a hairpin structure were identified as candidates for the factor that could be responsible for the differences between strong and weak plastome types. Ample sequence variation allowed phylogenetic inferences to be made about the relationships among the plastomes. Phylogenetic trees also could be constructed for most of the families of direct repeats. The amplifications and deletions of repeats that account for the size variation at oriB are proposed to have occurred through extensive replication slippage at this site.

The salvage/turnover/repair (STOR) model for uniparental inheritance in Chlamydomonas: DNA as a source of sustenance.

The non-Mendelian inheritance of chloroplast genes in Chlamydomonas has engaged researchers for decades and has prompted numerous debates regarding molecular mechanisms and evolutionary significance. The hallmarks of chloroplast inheritance in Chlamydomonas are reviewed here, including observations on vegetative haploid cells, somatic hybrids, meiotic zygospores, and vegetative zygotes resulting from sexual reproduction. Models invoked to explain the typical uniparental maternal inheritance of chloroplast genes, and which center upon the presumed existence of sex-specific protectors and destroyers of chloroplast genomes, are briefly discussed. In an effort to bring together the diverse observations on chloroplast gene inheritance in somatic as well as sexual cells, a model is proposed that focuses on organelle DNA turnover as a source of sustenance for the cell during periods of starvation. The salvage/turnover/repair (STOR) model for chloroplast inheritance in Chlamydomonas proposes that as a consequence of the high ploidy of the chloroplast genome, many copies are dispensable; their degradation would provide nucleotides for recombination, repair, RNA synthesis and cell metabolism. The STOR model offers an alternative view of uniparental inheritance as a phenomenon of direct selective benefit to the organism rather than simply being of selfish benefit to the chloroplast genome. These concepts may also have application to other lower eukaryotes that have sexual reproduction coupled with an extended dormancy.

Genetically Programmed Chloroplast Dedifferentiation as a Consequence of Plastome-Genome Incompatibility in Oenothera.

Comparision of chloroplast from plants with one of four plastome types (I, II, III, IV) in the nuclear background of Oenothera elata strain Johansen addressed the effects of plastome-genome incompatibility with respect to leaf pigmentation, plastid ultrastructure, chlorophyll a/chlorophyll b ratio, and photosynthetic electron transport. Previous observations of plastomes I, II, and IV in this nuclear background have revealed no indications of incompatibility, but the studies reported here demonstrate that chloroplasts of plastome IV have subtle alterations in their photosynthetic abilities, in particular, deficiencies in photosystem II. The well-characterized "hybrid bleaching" of plants with the AA genotype and plastome III involves leaves that become bleached in the center while remaining green at the tips, edges, and veins. Electron transport assays performed on fractionated bleached and green tissue from the same plants show photosynthetic defects in both the green and bleached regions, although defects in the latter are more severe. Ultrastructural studies show that chloroplasts in the bleached areas enlarge, thylakoid membranes become swollen and vesiculated, and production of new thylakoids is blocked, with chloroplasts appearing to undergo a programmed senescence. A time course revealed that the senescence is actually a reversible dedifferentiation. Alterations in the composition of medium to which AA/III seedlings were transferred showed that the presence of auxin can prevent the development of the typical incompatibility response, with leaf tissue remaining green rather than bleaching. It is proposed that differences in concentrations of plant growth regulators may be responsible for the persistence of normal chloroplasts near the vascular tissue and leaf blade edges and that seasonal fluctuations in auxin levels could explain the periodic bleaching that occurs in older plants.

Phylogenetic classification of phytopathogenic mollicutes by sequence analysis of 16S ribosomal DNA.

The phylogenetic relationships of 17 phytopathogenic mycoplasmalike organisms (MLOs) representing seven major taxonomic groups established on the basis of MLO 16S ribosomal DNA (rDNA) restriction patterns were examined by performing a sequence analysis of the 16S rDNA gene. The sequence data showed that the MLOs which we examined are members of a relatively homogeneous group that evolved monophyletically from a common ancestor. In agreement with results obtained previously with other MLOs, our results also revealed that the organisms are more closely related to Acholeplasma laidlawii and other members of the anaeroplasma clade than to any other mollicutes. A phylogenetic tree based on 16S rDNAs showed that the MLOs which we examined can be divided into the following five primary clusters: (i) the aster yellows strain cluster; (ii) the apple proliferation strain cluster; (iii) the western-X disease strain cluster; (iv) the sugarcane white leaf strain cluster; and (v) the elm yellows strain cluster. The aster yellows, western-X disease, and elm yellows strain clusters were divided into two subgroups each. MLOs whose 16S rDNA sequences have been determined previously by other workers can be placed in one of the five groups. In addition to the overall division based on 16S rDNA sequence homology data, the primary clusters and subgroups could be further defined by a number of positions in the 16S rDNAs that exhibited characteristic compositions, especially in the variable regions of the gene.

Phylogenetic relationships among members of the class Mollicutes deduced from rps3 gene sequences.

A gene for a ribosomal protein, rps3, was amplified by PCR and sequenced from representatives of the class Mollicutes. Alignments of the deduced amino acid sequences allowed the construction of a phylogeny that is consistent with the phylogenetic trees created from 5S and 16S rRNA comparisons, including the position of the former Acholeplasma florum on the Mycoplasma branch, rather than with the classical Acholeplasmataceae. Additional confirmation of the phylogeny comes from the deduction that the UGA triplet encodes tryptophan in the rps3 gene from Mesoplasma florum, as it does in the mycoplasmas and spiroplasmas. The sequence data from Acholeplasma axanthum 743 and Acholeplasma sp. strain J233 allow refinements to the phylogenetic tree within the Acholeplasmataceae, providing evidence that the sterol requirement of Anaeroplasma abactoclasticum (order Anaeroplasmatales) is a derived trait. It was also evident that the nonhelical plant-pathogenic members of the class Mollicutes, referred to as mycoplasma-like organisms or phytoplasmas, are more closely related to the true acholeplasmas (Acholeplasma laidlawii and strain J233) than to other members of the Mollicutes.

Plastome-genome interactions affect plastid transmission in Oenothera.

Plastids of Oenothera, the evening primrose, can be transmitted to the progeny from both parents. In a constant nuclear background, the frequency of biparental plastid transmission is determined by the types of plastid genomes (plastomes) involved in the crosses. In this study, the impact of nuclear genomes on plastid inheritance was analyzed. In general, the transmission efficiency of each plastome correlated strongly with its compatibility with the nuclear genome of the progeny, suggesting that plastome-genome interactions can influence plastid transmission by affecting the efficiency of plastid multiplication after fertilization. Lower frequencies of plastid transmission from the paternal side were observed when the pollen had poor vigor due to an incompatible plastome-genome combination, indicating that plastome-genome interactions may also affect the input of plastids at fertilization. Parental traits that affect the process of fertilization can also have an impact on plastid transmission. Crosses using maternal parents with long styles or pollen with relatively low growth capacity resulted in reduced frequencies of paternal plastid transmission. These observations suggest that degeneration of pollen plastids may occur as the time interval between pollination and fertilization is lengthened.

Large unidentified open reading frame in plastid DNA (ORF2280) is expressed in chloroplasts.

The chloroplast DNA encodes genes for components of photosynthesis and the transcription-translation machinery; a number of unidentified open reading frames (ORFs) are also present. To determine whether a large ORF in the inverted repeat of chloroplast DNA of tobacco (ORF2280) encodes a chloroplast protein, a conserved region of the ORF was expressed in Escherichia coli. An antibody against the ORF protein was prepared using the purified fusion protein as an antigen. When incubated with proteins from the soluble fraction of tobacco, spinach and Oenothera chloroplasts, the antiserum detects relatively labile polypeptides, which have apparent molecular weights of 170 to 180 kDa. The ORF in tobacco and spinach is large enough to encode a protein of 240-250 kDa, thus it is possible that post-transcriptional or post-translational processing reduces the size of the expression product. Analysis of Oenothera chloroplasts representing four different plastome types revealed endonuclease restriction fragment length polymorphisms in chloroplast DNA indicative of insertion/deletion events in a region of the chloroplast DNA that shared significant sequence similarity with ORF2280. The ORF2280 antiserum was used to demonstrate that there are qualitative differences in the ORF proteins from different Oenothera plastome types.