Mutators and long-term molecular evolution of pathogenic Escherichia coli O157:H7.

It has been proposed that an increased mutation rate (indicated by the frequency of hypermutable isolates) has facilitated the emergence of Escherichia coli O157:H7. Analysis of the divergence of 12 genes shows no evidence that the pathogen has undergone an unusually high rate of mutation and molecular evolution

Centurus

p. 217-273, [4] p. of plates : ill., maps ; 27 cm.Includes bibliographical references (p. 268-273)."This study is concerned with the systematic relationships among certain populations of woodpeckers of the genus Centurus occurring in the United States, México, and Central America. Significant conclusions arising from this investigation, which has involved field work in México in 1958 and examination of large numbers of museum specimens, are as follows: The generic name Tripsurus is regarded as a synonym of Centurus, since there is no known character or combination of characters that distinguishes species currently assigned to these two nominal genera. Moreover, one species, chrysogenys, that is invariably assigned to Centurus is actually more closely related to species currently assigned to Tripsurus. Centurus (sensu lato) is closely allied with, and possibly inseparable from, Melanerpes. Quantitative analysis of morphologic characters of specimens that represent populations of the aurifrons complex fully supports the view of Ridgway (1881) and Griscom (1932) that these populations belong to a single, highly polytypic species, since even the most strongly differentiated forms (C. a. aurifrons and C. a. dubius) intergrade in zones of contact. It is advocated that the number of subspecies for continental populations be limited to five; these are C. a. aurifrons (including C. a. incanescens of recent classifications), C. a. dubius (including C. a. leei of Cozumel Island, Yucatán), C. a. grateloupensis (including C. a. veraecrucis), C. a. santacruzi (including C. a. pauper and C. a. fumosus), and C. a. polygrammus (including C. a. frontalis). The color and pattern of the plumage in Centurus species are presumably cryptic, and geographic variation in these characters shows a reasonably close correlation with regional variation in climate and vegetation type. The brightly colored, sexually dimorphic areas of the head (and perhaps also the brightly colored belly region) presumably have epigamic significance. It is probable that Centurus hoffmanni of Costa Rica and Nicaragua is specifically distinct from C. aurifrons. Field work in restricted zones of sympatry between Centurus aurifrons and C. uropygialis in Aguascalientes and Jalisco indicates that the two forms are specifically distinct. Approximately 5 per cent of the specimens taken in the zones of sympatry show evidence of hybrid origin, but gene exchange between the two forms is not extensive, if in fact it occurs at all. The presence of traces of yellow pigment on the nape of specimens of C. uropygialis throughout its range is interpreted not as evidence of present-day introgression of genes from C. aurifrons but as a vestige of a character more fully developed in a population ancestral to C. uropygialis and currently being lost in that species. A specific relationship of Centurus aurifrons and C. carolinus is demonstrated by their sympatry without interbreeding in a narrow zone in Texas. Contrary to the suggestion of Peters (1948), Centurus hypopolius is probably not conspecific with C. uropygialis, and it may be more closely allied to C. chrysogenys, with which it is sympatric in Puebla and Morelos. The Haitian woodpecker, Chryserpes striatus, which has been assigned to Centurus by Bond and others, is not closely allied to any species of Centurus or Melanerpes and should be placed in the monotypic genus Chryserpes, as advocated by W.D. Miller, pending further study of its relationships. The significance of ecologic range or amplitude in distribution and speciation in birds is discussed. For Centurus it is suggested that the evolution of reproductive isolating mechanisms tends to proceed more rapidly than does the evolution of ecologic isolation, with the result that competition and other interspecific interactions prevent extensive sympatry of closely related species of the genus. The possible ecologic significance of increased degrees of sexual dimorphism in size, particularly in bill length, in certain insular woodpeckers is discussed, but, in the absence of comparative ecologic and behavioral studies, no satisfactory explanation of the phenomenon can be given"--P. 267

Long-term clinical and economic outcomes in previously untreated paediatric patients with severe haemophilia A : A nationwide real-world study with 700 person-years

AimFor previously untreated patients (PUPs) with severe haemophilia A in Finland for the past 2 decades, the standard practice has been to start early primary prophylaxis. We evaluated the long-term clinical outcomes and costs of treatment with high-dose prophylaxis in PUPs from birth to adolescence, including immune tolerance induction (ITI). MethodsFrom the medical records of all PUPs born between June 1994 and May 2013 in Finland, we retrospectively extracted data on clinical outcomes and healthcare use. Using linear mixed models, we analysed longitudinal clinical outcome data. To analyse skewed cost data, including zero costs, we applied hurdle regression. ResultsAll 62 patients received early regular prophylaxis; totally, they have had treatment for nearly 700 patient-years. The median age of starting home treatment was 1.1years. The mean (SD) annual treatment costs (Europerkg) were 4391Euro (3852). For ages 1-3, ITI comprised over half of the costs; in other groups, prophylactic FVIII treatment dominated. With these high costs, however, clinical outcomes were desirable; median (IQR) ABR was low at 0.19 (0.07-0.46) and so was AJBR at 0.06 (0-0.24). Thirteen (21%) patients developed a clinically significant inhibitor, 10 (16%) with a high titre. All ITIs were successful. The mean costs for ITI were 383448Euro (259085). The expected ITI payback period was 1.81 (95% CI 0.62-12.12) years. ConclusionsEarly high-dose prophylaxis leads to excellent long-term clinical outcomes, and early childhood ITI therapy seems to turn cost-neutral generally already in 2years.Peer reviewe

Genetic Polymorphism in Evolving Population

We present a model for evolving population which maintains genetic polymorphism. By introducing random mutation in the model population at a constant rate, we observe that the population does not become extinct but survives, keeping diversity in the gene pool under abrupt environmental changes. The model provides reasonable estimates for the proportions of polymorphic and heterozygous loci and for the mutation rate, as observed in nature

Adverse perinatal outcomes among practical nurses : the Finnish medical birth register study

Work as a practical nurse (nurse assistant) may have an effect on pregnancy outcomes. Exposure to chemical, physical and biological hazards are common among hospital personnel. Stressful work conditions such as shift work, prolonged standing and long working hours have been reported among practical nurses. The aim of this study was to examine whether working as a practical nurse is associated with adverse perinatal outcomes. Data were obtained from the Finnish Medical Birth Register of 1997-2014. We included 58512 singleton newborns of practical nurses as cases, and 8765 and 39485 newborns of secretaries and housewives, respectively, as controls. Outcomes included preterm birth (<37 weeks), low birthweight (<2500 g), perinatal death (stillbirth or neonatal death within the first seven days), SGA (<2.5th percentile), and breech presentation, among others. Logistic regression analysis was performed and adjusted for confounders such as maternal age, parity, smoking, and diabetes. Being a practical nurse had lower likelihood of low birthweight (OR=0.88; 95% CI: 0.81-0.96), perinatal death (OR=0.77; 95% CI: 0.62-0.96), SGA (OR=0.79; 95% CI: 0.72-0.86) and episiotomy (OR=0.90; 95% CI: 0.86-0.94). Practical nursing was significantly related to higher odds of instrumental delivery (OR=1.08; 95% CI: 1.00-1.17), but not with preterm birth, breech presentation, shoulder presentation, or caesarean section. After adjusting for confounding variables, working as a practical nurse was associated with higher likelihood of instrumental delivery, particularly vacuum delivery. The risk for shoulder presentation was nearly two-fold compared to controls. Further studies to determine when mothers started their maternity leave and the consequent effect on pregnancy outcome is highly recommended. [Abstract copyright: © 2021 Kwegyir-Afful E. et al.

Rhodium(II)-catalyzed stereocontrolled synthesis of dihydrofuran-3-imines from 1-Tosyl-1,2,3-triazoles

Rhodium(II) acetate catalyzes the denitrogenative transformation of 5-substituted and 4,5-disubstituted 1-sulfonyl-1,2,3-triazoles with pendent allyl and propargyl ether motifs to oxonium ylides that undergo [2,3]-sigmatropic rearrangement to give substituted dihydrofuran-3-imines in high yield and diastereoselectivity

Parthenogenesis In The Tropical Gekkonid Lizard, Nactus Arnouxii (Sauria: Gekkonidae)

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137400/1/evo02464.pd

Studies on the genetic and non-genetic (physiological) variation of human erythrocyte glutamic oxaloacetic transaminase

The thermostability profile of seven different electrophoretic variants of human erythrocyte GOT found in 13 different, unrelated families from a racially heterogeneous population was examined. The five different slow-variant and the two different fast-variant classes could be grouped into four different thermostability classes which were termed unstable, less stable, normal and more stable than normal. The thermostability differences among and within the electrophoretic variant classes permitted differentiation of the 13 individusals possessing an electrophoretic variant phenotype into a total of ten different variants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66025/1/j.1469-1809.1982.tb00711.x.pd

Connexin-mimetic peptide Gap 27 decreases osteoclastic activity

BACKGROUND: Bone remodelling is dependent on the balance between bone resorbing osteoclasts and bone forming osteoblasts. We have shown previously that osteoclasts contain gap-junctional protein connexin-43 and that a commonly used gap-junctional inhibitor, heptanol, can inhibit osteoclastic bone resorption. Since heptanol may also have some unspecific effect unrelated to gap-junctional inhibition we wanted to test the importance of gap-junctional communication to osteoclasts using a more specific inhibitor. METHODS: A synthetic connexin-mimetic peptide, Gap 27, was used to evaluate the contribution of gap-junctional communication to osteoclastic bone resorption. We utilised the well-characterised pit-formation assay to study the effects of the specific gap-junctional inhibitor to the survival and activity of osteoclasts. RESULTS: Gap 27 caused a remarked decrease in the number of both TRAP-positive mononuclear and multinucleated rat osteoclasts cultured on bovine bone slices. The decrease in the cell survival seemed to be restricted to TRAP-positive cells, whereas the other cells of the culture model seemed unaffected. The activity of the remaining osteoclasts was found to be diminished by measuring the percentage of osteoclasts with actin rings of all TRAP-positive cells. In addition, the resorbed area in the treated cultures was greatly diminished. CONCLUSIONS: On the basis of these results we conclude that gap-junctional communication is essential for the action of bone resorbing osteoclasts and for proper remodelling for bone