Dual origin of tissue-specific progenitor cells in Drosophila tracheal remodeling     

Weaver M  Krasnow MA 《Science (New York, N.Y.)》2008,321(5895):1496-1499

During Drosophila metamorphosis, most larval cells die. Pupal and adult tissues form from imaginal cells, tissue-specific progenitors allocated in embryogenesis that remain quiescent during embryonic and larval life. Clonal analysis and fate mapping of single, identified cells show that tracheal system remodeling at metamorphosis involves a classical imaginal cell population and a population of differentiated, functional larval tracheal cells that reenter the cell cycle and regain developmental potency. In late larvae, both populations are activated and proliferate, spread over and replace old branches, and diversify into various stalk and coiled tracheolar cells under control of fibroblast growth factor signaling. Thus, Drosophila pupal/adult tissue progenitors can arise both by early allocation of multipotent cells and late return of differentiated cells to a multipotent state, even within a single tissue.  相似文献   

Ecology. Better science needed for restoration in the Gulf of Mexico     

Bjorndal KA  Bowen BW  Chaloupka M  Crowder LB  Heppell SS  Jones CM  Lutcavage ME  Policansky D  Solow AR  Witherington BE 《Science (New York, N.Y.)》2011,331(6017):537-538

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ACTION OF ALTHESIN AND KETAMINE ON HIGH ENERGY PHOPHATES AND LACTATE FORMATION I N SKELETAL MUSCLE OF NORMAL AND MALIGNANT HYPERTHERMIA SUSCEPTIB PIGS     

J. V. McLoushlin  C. P. Ahern  P. Wilson 《Veterinary anaesthesia and analgesia》1980,9(1):125-130

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Enzymatic solubilization of fish protein concentrate: batch studies applicable to continuous enzyme recycling processes     

C Cheftel  M Ahern  D I Wang  S R Tannenbaum 《Journal of agricultural and food chemistry》1971,19(1):155-161

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Halothane-induced malignant hyperthermia in Irish pig breedsHyperthermie maligne induite par l'halothane dans les races porcines irlandaisesHalothan induzierte maligne hyperthermie bei Irischen schweinerassen     

Patricia McGloughlin  C.P. Ahern  Mary Butler  J.V. McLoughlin 《Livestock Production Science》1980,7(2):147-154

A total of 567 young pigs entering one of the national testing stations were tested for sensitivity to halothane between October 1976 and May 1978. They included 443 Landrace, 76 Large White and 48 Irish Welsh. The average weight at testing was 25.6 kg. A total of 24 pigs reacted positively to the test, 21 (4.6%) of the Landrace and 3 (6.3%) of the Irish Welsh. No reactors were found in the Large White breed.Meat quality estimates in the form of the pH in the longissimus dorsi muscle 45 min post-mortem (pH₁) were recorded on the 324 slaughtered pigs. Reactor pigs (ten) had significantly lower values than non-reactors, indicating a greater tendency to develop quality problems such as pale, soft, exudative (PSE) meat. There was an indication that reactor pigs might have slightly reduced daily gains and lower backfat thickness.  相似文献   

Effect of strain and serotype of vesicular stomatitis virus on viral shedding, vesicular lesion development, and contact transmission in pigs     

Stallknecht DE  Greer JB  Murphy MD  Mead DG  Howerth EW 《American journal of veterinary research》2004,65(9):1233-1239

OBJECTIVE: To determine whether pigs can be infected with strains of vesicular stomatitis virus New Jersey (VSV-NJ) and vesicular stomatitis virus Indiana (VSV-I) isolated during recent vesicular stomatitis outbreaks that primarily involved horses in the western United States and determine the potential for these viruses to be transmitted by contact. ANIMALS: 128 pigs. PROCEDURE: Pigs were challenged with VSV-NJ or VSV-I from the 1995 and 1997 outbreaks of vesicular stomatitis in the western United States, respectively, or with VSV-NJ (OS) associated with vesicular stomatitis in feral pigs on Ossabaw Island, Ga. Pigs (3/group) were inoculated with each virus via 3 routes and evaluated for viral shedding, seroconversion, and the development of vesicular lesions. In another experiment, the potential for contact transmission of each virus from experimentally infected to na?ve pigs was evaluated. RESULTS: Infection of pigs was achieved for all 3 viruses as determined by virus isolation and detection of seroconversion. In inoculated pigs, all 3 viruses were isolated from multiple swab samples at concentrations sufficient to infect other pigs. However, compared with results obtained with the 2 VSV-NJ strains, viral titers associated with VSV-I were low and the duration of virus shedding was reduced. Results from the contact transmission trials were consistent with these results; virus transmission was detected most frequently with the VSV-NJ strains. CONCLUSIONS AND CLINICAL RELEVANCE: Pigs can be infected with VSV-NJ and VSV-I. Differences in the extent of viral shedding and potential for contact transmission were apparent between serotypes but not between the VSV-NJ strains investigated.  相似文献   

Sensitivities of three county health department surveillance systems for child-related dog bites: 261 cases (2000)   总被引：1，自引：0，他引：1  

Tan RL  Powell KE  Lindemer KM  Clay MM  Davidson SC 《Journal of the American Veterinary Medical Association》2004,225(11):1680-1683

OBJECTIVES: To determine incidence of child-related dog bites and sensitivities of 3 county health department dog-bite surveillance systems. DESIGN: Retrospective study. STUDY POPULATION: Child-related dog-bite data obtained from surveillance systems of 3 counties in Georgia in the year 2000. PROCEDURE: To characterize the sensitivity of health department dog-bite surveillance systems, 9 other potential sources of dog-bite records that matched records by victim name, age, gender, and incident date were evaluated. The number of reported bites and the most productive sources for identifying additional cases were determined. The Chandra Sekar-Deming capture-recapture method was used to estimate the number of unreported bites, and estimates of dog-bite incidence rates were made. RESULTS: 40, 36, and 185 dog bites were reported in the 3 counties, respectively. Capture-recapture calculations estimated an additional 9, 5, and 128 dog bites in these counties, respectively. Local health departments recorded 45.5% to 82.5% of dog bites. Local hospital emergency departments, police departments, and a rabies-testing laboratory received additional reports. Among these data sources, local hospital emergency department records were the best source for identifying additional cases. CONCLUSIONS AND CLINICAL RELEVANCE: Dog bites are a preventable cause of childhood injuries, and surveillance is a critical tool for tracking childhood dog bites in the community. Counties should use combined data from local health departments, local hospital emergency departments, and police departments to implement or revise dog-bite prevention programs.  相似文献   

Germline mutations in genes within the MAPK pathway cause cardio-facio-cutaneous syndrome   总被引：1，自引：0，他引：1  

Rodriguez-Viciana P  Tetsu O  Tidyman WE  Estep AL  Conger BA  Cruz MS  McCormick F  Rauen KA 《Science (New York, N.Y.)》2006,311(5765):1287-1290

Cardio-facio-cutaneous (CFC) syndrome is a sporadic developmental disorder involving characteristic craniofacial features, cardiac defects, ectodermal abnormalities, and developmental delay. We demonstrate that heterogeneous de novo missense mutations in three genes within the mitogen-activated protein kinase (MAPK) pathway cause CFC syndrome. The majority of cases (18 out of 23) are caused by mutations in BRAF, a gene frequently mutated in cancer. Of the 11 mutations identified, two result in amino acid substitutions that occur in tumors, but most are unique and suggest previously unknown mechanisms of B-Raf activation. Furthermore, three of five individuals without BRAF mutations had missense mutations in either MEK1 or MEK2, downstream effectors of B-Raf. Our findings highlight the involvement of the MAPK pathway in human development and will provide a molecular diagnosis of CFC syndrome.  相似文献   

Allelic relationships at the pvr1 locus in Capsicum annuum     

Je Min Lee  Molly M. Jahn  Inhwa Yeam 《Euphytica》2013,194(3):417-424

Diseases caused by members of the Potyviridae family currently threaten pepper crops (Capsicum annuum L.) worldwide. A series of monogenic recessive resistance genes that control potyvirus resistance at the pvr1 locus in Capsicum species are widely known and used in pepper breeding programs, each allele with a differential resistance spectrum affecting a distinct range of viral strains across three viruses, Tobacco etch virus (TEV), Pepper mottle virus and Potato virus Y. In this study, we systematically analyzed the resistant spectra, and the level of the resistance each allele confers using a set of pepper genotypes homozygous or heterozygous for the following alleles; Pvr1 ⁺, pvr1, pvr1 ¹ and pvr1 ². The resistance alleles at the pvr1 locus show recessive inheritance when combined with a susceptible allele in F1 progenies. However, our results show that resistance in this system is, in fact, not always fully recessive and establish a hierarchy of allelic interactions We identified the resistance phenotype in F₁ progenies generated by combining a complete resistant allele with an incomplete resistance allele against TEV strains implying that the resistance alleles at the pvr1 shows dominant inheritance when combined with an incomplete resistance allele. Resistance alleles against TEV-HAT, pvr1 and pvr1 ², show dominance inheritance when each is combined with pvr1 ¹. The resistance allele, pvr1, shows dominance inheritance when combined with pvr1 ² against TEV-N. These results clarify the allelic relationship between resistance alleles at the pvr1 locus displaying different resistance spectra, and will assist breeders to select the preferred combinations of the resistance alleles to obtain durable resistance against multiple potyviral strains.  相似文献   

The Impact of Hardwood Line-Planting on Tree and Amphibian Diversity in a Secondary Subtropical Wet Forest of Southeast Puerto Rico     

Mark Nelson  Sally Silverstone  Kelly C. Reiss  Patricia Burrowes  Rafael Joglar  Molly Robertson 《Journal of Sustainable Forestry》2013,32(5):503-516

The impact on tree and amphibian diversity of line-planting of tropical hardwoods—mahogany (Swietenia macrophylla × S. mahagoni) and mahoe (Hibiscus elatus)—was studied in a secondary subtropical wet forest of Puerto Rico. Common coqui (Eleutherodactylus coqui) and melodious coqui (E. wightmanae) are the most frequent frog species; forest coqui (E. portoricensis) is less abundant. Although relative abundance means were slightly greater in the undisturbed forest and during the wet season, differences were not statistically significant suggesting that line-planting did not significantly affect amphibian diversity. The line-planted areas had a slightly higher, but not statistically significant diversity, richness, and evenness of tree species than the unplanted forest. Multi-response permutation procedure (MRPP) showed statistically significant community composition differences between line-planting and control plot trees (T = ?5.89, A = .86; p < .001). But mean similarity among plots in both the line-planted and control plots was relatively low at less than 50% of shared species, indicating high diversity of vegetation in the overall forest area. Canopy cover by tree species greater than 3 cm in dbh was much higher in the undisturbed forest but this difference may be reduced as the young line-planted hardwoods mature. Forest enrichment through line-planting of valuable timber species in secondary subtropical wet forest does not significantly affect tree diversity.  相似文献