Appropriate selection of parents for the development of mapping populations is pivotal to maximizing the power of quantitative trait loci detection. Trait genotypic variation within a family is ...indicative of the family's informativeness for genetic studies. Accurate prediction of the most useful parental combinations within a species would help guide quantitative genetics studies. We tested the reliability of genotypic and phenotypic distance estimators between pairs of maize inbred lines to predict genotypic variation for quantitative traits within families derived from biparental crosses. We developed 25 families composed of ~200 random recombinant inbred lines each from crosses between a common reference parent inbred, B73, and 25 diverse maize inbreds. Parents and families were evaluated for 19 quantitative traits across up to 11 environments. Genetic distances (GDs) among parents were estimated with 44 simple sequence repeat and 2303 single-nucleotide polymorphism markers. GDs among parents had no predictive value for progeny variation, which is most likely due to the choice of neutral markers. In contrast, we observed for about half of the traits measured a positive correlation between phenotypic parental distances and within-family genetic variance estimates. Consequently, the choice of promising segregating populations can be based on selecting phenotypically diverse parents. These results are congruent with models of genetic architecture that posit numerous genes affecting quantitative traits, each segregating for allelic series, with dispersal of allelic effects across diverse genetic material. This architecture, common to many quantitative traits in maize, limits the predictive value of parental genotypic or phenotypic values on progeny variance.
The efficacy of partial ventilatory support modes that allow spontaneous breathing in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is unclear. The objective of ...this scoping review was to assess the effects of partial ventilatory support on mortality, duration of mechanical ventilation, and both hospital and intensive care unit (ICU) lengths of stay (LOS) for patients with ALI and ARDS; the secondary objective was to describe physiologic effects on hemodynamics, respiratory system and other organ function.
MEDLINE (1966-2009), Cochrane, and EmBase (1980-2009) databases were searched using common ventilator modes as keywords and reference lists from retrieved manuscripts hand searched for additional studies. Two researchers independently reviewed and graded the studies using a modified Oxford Centre for Evidence-Based Medicine grading system. Studies in adult ALI/ARDS patients were included for primary objectives and pre-clinical studies for supporting evidence.
Two randomized controlled trials (RCTs) were identified, in addition to six prospective cohort studies, one retrospective cohort study, one case control study, 41 clinical physiologic studies and 28 pre-clinical studies. No study was powered to assess mortality, one RCT showed shorter ICU length of stay, and the other demonstrated more ventilator free days. Beneficial effects of preserved spontaneous breathing were mainly physiological effects demonstrated as improvement of gas exchange, hemodynamics and non-pulmonary organ perfusion and function.
The use of partial ventilatory support modalities is often feasible in patients with ALI/ARDS, and may be associated with short-term physiological benefits without appreciable impact on clinically important outcomes.
A total of 800 meat and poultry products were purchased from the retail marketplace in Edmonton, Alberta, Canada. The products consisted of raw ground beef, chicken legs, pork chops, and ready-to-eat ...fermented sausage, roast beef, processed turkey breast, chicken wieners, and beef wieners. The samples were analyzed to determine the prevalence of Shiga toxin-producing Escherichia coli, Salmonella, Campylobacter spp., and Listeria monocytogenes. Shiga toxin-producing E. coli O22: H8 was found in one raw ground beef sample. Salmonella and Campylobacter were found in 30 and 62% of raw chicken legs, respectively. L. monocytogenes was found in 52% of raw ground beef, 34% of raw chicken legs, 24% of raw pork chops, 4% of fermented sausages, 3% of processed turkey breast, 5% of beef wieners, and 3% of chicken wieners. The occurrence of pathogens in this study is similar to that in retail products in many other international locales.
Cyanosis McMullen, Sarah M., MD; Patrick, Ward, MD
The American journal of medicine,
03/2013, Letnik:
126, Številka:
3
Journal Article
Recenzirano
Descriptions of cyanopathia or Morbus caeruieus have populated medical literature since the time of Hippocrates, although the actual pathophysiology behind its development eluded physicians until the ...advent of objective anatomy and physiology. Morgagni, "accurate anatomist," philosopher, and one of the fathers of contemporary medicine, is often credited with having first described cyanosis, however, it was actually deSenac, personal physician to King Louis XV who first described the pathophysiology of cyanosis in 1749. It was not until over 2 centuries later, however, that Christen Lundsgaard actually quantified the amount of deoxygenated hemoglobin that was required to produce that bluish discoloration that produces the clinical finding of cyanosis. Here, McMullen and Patrick discuss the features, pathophysiology, and associated conditions of cyanosis.
Shiga-toxin producing Escherichia coli (STEC) causes human illness ranging from mild diarrhea to death. The bacteriophage encoded stx genes are located in the late transcription region, downstream of ...the antiterminator Q. The transcription of the stx genes is directly under the control of the late promoter pR’, thus the sequence diversity of the region between Q and stx, here termed the pR’ region, may affect Stx toxin production. Here, we compared the gene structure of the pR’ region and the stx subtypes of nineteen STECs. The sequence alignment and phylogenetic analysis suggested that the pR’ region tends to be more heterogeneous than the promoter itself, even if the prophages harbor the same stx subtype. Furthermore, we established and validated transcriptional fusions of the pR’ region to the DsRed reporter gene using mitomycin C (MMC) induction. Finally, these constructs were transformed into native and non-native strains and examined with flow cytometry. The results showed that induction levels changed when pR’ regions were placed under different regulatory systems. Moreover, not every stx gene could be induced in its native host bacteria. In addition to the functional genes, the diversity of the pR’ region plays an important role in determining the level of toxin induction.
The aim of this study was to assess the influence of sodium content on the microbiota on the surface of ready-to-eat (RTE) meat products purchased from the retail market in Canada. Products, ...including sliced and sausage-type deli meats, were analysed with culture-dependent and culture-independent methods. Bacteria were identified from 23 brands of products from different meat processors with claims of sodium content ranging from 390 to 1200 mg per 100 g of product. Out of 150 bacterial isolates, the most common were identified as Leuconostoc gelidum, Carnobacterium maltaromaticum, Brochothrix thermosphacta, and Leuconostoc gasicomitatum. Vacuum-packaged RTE deli sliced meat products had the largest population of bacteria. Leuconostocci were the most common isolates in this group of products, while carnobacteria were prevalent on products with moderate loads of bacteria. A higher incidence of carnobacteria and lower incidence of B. thermosphacta were detected on sodium-reduced products. Simpson’s and Shannon–Wiener indices showed that low sodium products (25%–50% less sodium) had an overall higher bacterial diversity. This was also observed when individual low sodium products were compared with their regular sodium counterpart.
Crop species experienced strong selective pressure directed at genes controlling traits of agronomic importance during their domestication and subsequent episodes of selective breeding. Consequently, ...these genes are expected to exhibit the signature of selection. We screened 501 maize genes for the signature of selection using microsatellites or simple sequence repeats (SSRs). We applied the Ewens-Watterson test, which can reveal deviations from a neutral-equilibrium model, as well as two nonequilibrium tests that incorporate the domestication bottleneck. We investigated two classes of SSRs: those known to be polymorphic in maize (Class I) and those previously classified as monomorphic in maize (Class II). Fifteen SSRs exhibited some evidence for selection in maize and 10 showed evidence under stringent criteria. The genes containing nonneutral SSRs are candidates for agronomically important genes. Because demographic factors can bias our tests, further independent tests of these candidates are necessary. We applied such an additional test to one candidate, which encodes a MADS box transcriptional regulator, and confirmed that this gene experienced a selective sweep during maize domestication. Genomic scans for the signature of selection offer a means of identifying new genes of agronomic importance even when gene function and the phenotype of interest are unknown.
The main hydroxamic acid in maize (Zea mays L.) is 2-4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA confers resistance to leaf-feeding by several corn borers. Most genes involved in the ...DIMBOA metabolic pathway are located on the short arm of chromosome 4, and quantitative trait loci (QTLs) involved in maize resistance to leaf-feeding by corn borers have been localized to that region. However, the low resolution of QTL linkage mapping does not allow convincing proof that genetic variation at bx loci was responsible for the variability for resistance. This study addressed the following objectives: to determine the QTLs involved in DIMBOA synthesis across genetically divergent maize inbreds using eight RIL families from the nested association mapping population, to check the stability of QTLs for DIMBOA content across years by evaluating two of those RIL families in 2 years, and to test the involvement of bx1 by performing association mapping with a panel of 281 diverse inbred lines. QTLs were stable across different environments. A genetic model including eight markers explained approximately 34% of phenotypic variability across eight RIL families and the position of the largest QTL co-localizes with the majority of structural genes of the DIMBOA pathway. Candidate association analysis determined that sequence polymorphisms at bx1 greatly affects variation of DIMBOA content in a diverse panel of maize inbreds, but the specific causal polymorphism or polymorphisms responsible for the QTL detected in the region 4.01 were not identified. This result may be because the causal polymorphism(s) were not sequenced, identity is masked by linkage disequilibrium, adjustments for population structure reduce significance of causal polymorphisms or multiple causal polymorphisms affecting bx1 segregate among inbred lines.
Daikon radish (Raphanus sativus) fermented with lactic acid bacteria, especially Leuconostoc or Lactobacillus spp., can be used to make kimchi, a traditional Korean fermented vegetable. Commercial ...Leuconostoc/radish root ferment filtrates are claimed to have broad spectrum antimicrobial activity. Leuconostoc kimchii fermentation products are patented as preservatives for cosmetics, and certain strains of this organism are reported to produce antimicrobial peptides (bacteriocins). We examined the antimicrobial agents in commercial Leuconostoc/radish root ferment filtrates. Both activity-guided fractionation with Amberlite XAD-16 and direct extraction with ethyl acetate gave salicylic acid as the primary agent with activity against Gram-negative bacteria. Further analysis of the ethyl acetate extract revealed that a didecyldimethylammonium salt was responsible for the Gram-positive activity. The structures of these compounds were confirmed by a combination of 1H- and 13C NMR, high-performance liquid chromatography, high-resolution mass spectrometry, and tandem mass spectrometry analyses. Radiocarbon dating indicates that neither compound is a fermentation product. No antimicrobial peptides were detected.
During the first week of the posthatching period, before the immune system is mature enough to produce its own B lymphocytes, a chick’s humoral immunity depends on maternal antibodies (IgY) received ...from the egg yolk. During incubation and after hatching, the yolk sac (YS) membrane transfers nutrients (including IgY) from the egg yolk to the developing embryo or newly hatched chick. The objective of this study was to determine the effects of breeder flock age on the total IgY content of egg yolks and chick YS from a commercial broiler breeder strain. Hatching eggs from the same broiler breeder flock were collected at 32, 40, and 55 wk of age. One group of eggs per flock age was used to determine the egg yolk total IgY content. Another group of eggs was incubated for 21.5 d, and upon hatching, the YS of newly hatched chicks were collected to determine the total IgY content. Egg and egg yolk weight increased with flock age, but YS weights did not reflect egg yolk weight. The total IgY content per gram of egg yolk increased with flock age; this fact plus the observed yolk weight increase with flock age notably increased the total IgY contained in yolks of eggs laid by 55-wk-old breeders. However, chicks hatching from 55-wk-old breeders had less IgY per gram of YS than chicks from 32- and 40-wk-old breeders. Whether there are differences in the rates of YS absorption between chicks of different breeder ages is unknown. This research provided total IgY values for broiler breeder egg yolk and chick YS of a commonly used meat-type chicken strain. Differences in egg yolk and YS total IgY contents due to flock age in this type of bird had not been previously reported. Research on the physiological consequences of YS absorption rates in chicks from different breeder ages is advised.
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