A Structural Perspective on the RNA Editing of Plant Respiratory Complexes

The last steps of respiration, a core energy-harvesting process, are carried out by a chain of multi-subunit complexes in the inner mitochondrial membrane. Several essential subunits of the respiratory complexes are RNA-edited in plants, frequently leading to changes in the encoded amino acids. While the impact of RNA editing is clear at the sequence and phenotypic levels, the underlying biochemical explanations for these effects have remained obscure. Here, we used the structures of plant respiratory complex I, complex III₂ and complex IV to analyze the impact of the amino acid changes of RNA editing in terms of their location and biochemical features. Through specific examples, we demonstrate how the structural information can explain the phenotypes of RNA-editing mutants. This work shows how the structural perspective can bridge the gap between sequence and phenotype and provides a framework for the continued analysis of RNA-editing mutants in plant mitochondria and, by extension, in chloroplasts.     

DM1 Transgenic Mice Exhibit Abnormal Neurotransmitter Homeostasis and Synaptic Plasticity in Association with RNA Foci and Mis-Splicing in the Hippocampus

Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disease mediated by a toxic gain of function of mutant RNAs. The neuropsychological manifestations affect multiple domains of cognition and behavior, but their etiology remains elusive. Transgenic DMSXL mice carry the DM1 mutation, show behavioral abnormalities, and express low levels of GLT1, a critical regulator of glutamate concentration in the synaptic cleft. However, the impact of glutamate homeostasis on neurotransmission in DM1 remains unknown. We confirmed reduced glutamate uptake in the DMSXL hippocampus. Patch clamp recordings in hippocampal slices revealed increased amplitude of tonic glutamate currents in DMSXL CA1 pyramidal neurons and DG granule cells, likely mediated by higher levels of ambient glutamate. Unexpectedly, extracellular GABA levels and tonic current were also elevated in DMSXL mice. Finally, we found evidence of synaptic dysfunction in DMSXL mice, suggestive of abnormal short-term plasticity, illustrated by an altered LTP time course in DG and in CA1. Synaptic dysfunction was accompanied by RNA foci accumulation in localized areas of the hippocampus and by the mis-splicing of candidate genes with relevant functions in neurotransmission. Molecular and functional changes triggered by toxic RNA may induce synaptic abnormalities in restricted brain areas that favor neuronal dysfunction.     

Analysis of microRNAs in Exosomes of Breast Cancer Patients in Search of Molecular Prognostic Factors in Brain Metastases

Brain metastases are the most severe tumorous spread during breast cancer disease. They are associated with a limited quality of life and a very poor overall survival. A subtype of extracellular vesicles, exosomes, are sequestered by all kinds of cells, including tumor cells, and play a role in cell-cell communication. Exosomes contain, among others, microRNAs (miRs). Exosomes can be taken up by other cells in the body, and their active molecules can affect the cellular process in target cells. Tumor-secreted exosomes can affect the integrity of the blood-brain barrier (BBB) and have an impact on brain metastases forming. Serum samples from healthy donors, breast cancer patients with primary tumors, or with brain, bone, or visceral metastases were used to isolate exosomes and exosomal miRs. Exosomes expressed exosomal markers CD63 and CD9, and their amount did not vary significantly between groups, as shown by Western blot and ELISA. The selected 48 miRs were detected using real-time PCR. Area under the receiver-operating characteristic curve (AUC) was used to evaluate the diagnostic accuracy. We identified two miRs with the potential to serve as prognostic markers for brain metastases. Hsa-miR-576-3p was significantly upregulated, and hsa-miR-130a-3p was significantly downregulated in exosomes from breast cancer patients with cerebral metastases with AUC: 0.705 and 0.699, respectively. Furthermore, correlation of miR levels with tumor markers revealed that hsa-miR-340-5p levels were significantly correlated with the percentage of Ki67-positive tumor cells, while hsa-miR-342-3p levels were inversely correlated with tumor staging. Analysis of the expression levels of miRs in serum exosomes from breast cancer patients has the potential to identify new, non-invasive, blood-borne prognostic molecular markers to predict the potential for brain metastasis in breast cancer. Additional functional analyzes and careful validation of the identified markers are required before their potential future diagnostic use.     

Emissions of metals associated with motor vehicle roadways

Emissions of metals and other particle-phase species from on-road motor vehicles were measured in two tunnels in Milwaukee, WI during the summer of 2000 and winter of 2001. Emission factors were calculated from measurements of fine (PM2.5) and coarse (PM10) particulate matter at tunnel entrances and exits, and effects of fleet composition and season were investigated. Cascade impactors (MOUDI) were used to obtain size-resolved metal emission rates. Metals were quantified with inductively-coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence (XRF). PM10 emission rates ranged from 38.7 to 201 mg km(-1) and were composed mainly of organic carbon (OC, 30%), inorganic ions (sulfate, chloride, nitrate, ammonium, 20%), metals (19%), and elemental carbon (EC, 9.3%). PM10 metal emissions were dominated by crustal elements Si, Fe, Ca, Na, Mg, Al, and K, and elements associated with tailpipe emissions and brake and tire wear, including Cu, Zn, Sb, Ba, Pb, and S. Metals emitted in PM2.5 were lower (11.6% of mass). Resuspension of roadway dust was dependent on weather and road surface conditions, and increased emissions were related to higher traffic volumes and fractions of heavy trucks. Emission of noble metals from catalytic converters appeared to be impacted by the presence of older vehicles. Elements related to brake wear were impacted by enriched road dust resuspension, but correlations between these elements in PM2.5 indicate that direct brake wear emissions are also important. A submicrometer particle mode was observed in the emissions of Pb, Ca, Fe, and Cu.     

Cooking beef joints from the frozen or thawed state

A comparative experimental study of cooking 2.25 kg beef joints from the frozen state with and without preliminary thawing has been made with respect to cooking times and losses, energy requirements and sensory differences. The cooking times and energy requirements of the joints cooked directly from ? 20°C were greater than those first thawed to 20°C by a factor of up to 2.3. No significant difference in cooking losses or juiciness was detected between the treatments; however, a statistically significant difference was found in the texture of samples cooked directly from frozen (mean ?0.8) and those previously thawed (mean +0.2). Samples cooked inside a roasting bag (moist heat) were also found to be significantly tougher than those cooked in an open tray (dry heat) the means being ?0.7 and +0.1 respectively, the texture being assessed on an eight point scale (+7 extremely tender to ?7 extremely tough) in each case.     

Analysis of Salmonella serotypes from selected carcasses and raw ground products sampled prior to implementation of the Pathogen Reduction; Hazard Analysis and Critical Control Point Final Rule in the US

In July 1996, the US Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS), published the Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) Systems final rule to improve food safety of meat and poultry products. The final rule established, among other requirements, pathogen reduction performance standards for Salmonella for food animal carcasses and raw ground products. The final rule is to be fully implemented in three stages in successively smaller federally inspected meat and poultry slaughter and processing establishments. Implementation began in January 1998 and was completed in January 2000. Samples of carcasses of four species of food animals (cattle, swine, chickens, turkeys), and raw ground product from each of these species, were collected by FSIS from establishments prior to implementation of the final rule and cultured for Salmonella. This paper reports Salmonella serotype results of samples collected from June 1997 through August 1998. These results represent a baseline for future comparisons.     

Studies on curcumin and curcuminoids XXI. Variation in the content of curcuminoids in Curcuma longa L. and Curcuma aromatica Salisb. from India during one season

Summary Three varieties ofCurcuma longa andC. aromatica were investigated during a growth period of 17 weeks with respect to the content of curcuminoids in the bulbs and fingers. A decrease in pigment production as a function of maturity of the rhizomes was observed. The total content of curcuminoids was equal inC. longa andC. aromatica, but with a slight difference in distribution between the fingers and bulbs in the two species. Taking the biomass into account, the fingers will be more beneficial for the isolation of curcuminoids than the respective bulbs.

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Studien über Curcumin und Curcuminoide XXI. Unterschiede des Gehaltes an Curcuminoiden bei Curcuma longa L. und Curcuma aromatica Salisb. aus Indien während einer Saison

Zusammenfassung Drei Typen vonCurcuma longa undC. aromatica wurden während einer Wachstumsperiode von 17 Wochen auf ihren Curcuminoidgehalt in den Knollen und im Wurzelstock untersucht. Eine Abnahme der Pigmentproduktion in Abhängigkeit von dem Entwicklungsstadium der Rhizome wurde festgestellt. Der Gesamtgehalt an Curcuminoiden beiC. longa undC. aromatica war der gleiche, doch bestand ein geringer Unterschied in der Verteilung dieser zwischen Knolle und Wurzelstock bei den beiden Spezies. Bei Betrachtung der Biomasse ist der Wurzelstock für die Isolation von Curcuminoiden besser geeignet als die Knollen.

     

Reproductive disruption in fish downstream from an estrogenic wastewater effluent

To assess the impact of an estrogenic wastewater treatment plant (WWTP) effluent on fish reproduction, white suckers (Catostomus commersoni) were collected from immediately upstream and downstream (effluent site) of the city of Boulder, CO, WWTP outfall. Gonadal intersex, altered sex ratios, reduced gonad size, disrupted ovarian and testicular histopathology, and vitellogenin induction consistent with exposure to estrogenic wastewater contaminants were identified in white suckers downstream from the WWTP outfall and not at the upstream site. The sex ratio was female-biased at the effluent site in both the fall of 2003 and the spring of 2004; the frequency of males at the effluent site (17-21%) was half that of the upstream site (36-46%). Intersex white suckers comprised 18-22% of the population at the effluent site. Intersex fish were not found at the upstream site. Chemical analyses determined that the WWTP effluent contained a complex mixture of endocrine-active chemicals, including 17beta-estradiol (E2) 17alpha-ethynylestradiol, alkylphenols, and bisphenol A resulting in an estimated total estrogen equivalence of up to 31 ng E2 L(-1). These results indicate that the reproductive potential of native fishes may be compromised in wastewater-dominated streams.