98 research outputs found
A single polymerase (L) mutation in avian metapneumovirus increased virulence and partially maintained virus viability at an elevated temperature
No full textPreviously a virulent avian metapneumovirus (AMPV) farm isolate Italy 309/04 was shown to have derived from a live vaccine. Virulence due to the five nucleotide mutations associated with the reversion to virulence, was investigated by their addition to the vaccine using reverse genetics. Virulence of these recombinant viruses was determined by infection of one-day-old turkeys. Disease levels resulting from the combined two matrix (M) mutations was indistinguishable from that produced by the recombinant vaccine, whereas the combined three L gene mutations increased disease to a level (p<0.0001) which was indistinguishable from that caused by the revertant Italy 309/04 virus. Testing of the L mutations individually showed that two did not increase virulence while the third, corresponding to an asparagine to aspartic acid substitution, produced virulence indistinguishable from that caused by Italy 309/04. In contrast to the vaccine, the virulent mutant also showed increased viability at temperatures typical of turkey core tissues. The notion that increased viral virulence resulted from enhanced ability to replicate in tissues away from the cool respiratory tract, cannot be discounted
Avian Metapneumoviruses in Italy: Evidence of attachment protein evolution coincident with mass live vaccine introduction
No full textAvian metapneumoviruses (AMPV) of subtype B dominate over other subtypes on
Italian poultry farms in northern Italy. AMPVs from the Veneto region of Italy between
1987 and 2007 were sequenced in their attachment (G) and fusion (F) protein genes,
together with other subtype B AMPVs from other parts of Western Europe, collected
prior to 1994. All viruses in the survey had very similar predicted F sequences
whereas the predicted G protein sequences found in Italy from 2001 were distinctly
different from those found in pre 1994 viruses. Nonetheless pre 1994 Italian AMPVs
were more similar to post 2000 AMPVs than other pre 1994 viruses from other parts
of Europe, thereby showing that the later viruses had probably evolved from early
Italian viruses. The occurrence of the later variants followed introduction of the mass
administration with a single subtype B vaccine and its G protein sequence placed it
clearly in the pre 1994 cluster. The possibility of the vaccine having driven field virus
evolution in order to evade immune pressure cannot be excluded
Avian metapneumovirus (AMPV) attachment protein involvement in probable virus evolution concurrent with mass live vaccine introduction
No full textAvian metapneumoviruses detected in Northern Italy between 1987 and 2007 were sequenced in their fusion (F) and attachment (G) genes together with the same genes from isolates collected throughout western European prior to 1994. Fusion protein genes sequences were highly conserved while G protein sequences showed much greater heterogeneity. Phylogenetic studies based on both genes clearly showed that later Italian viruses were significantly different to all earlier virus detections, including early detections from Italy. Furthermore a serine residue in the G proteins and lysine residue in the fusion protein were exclusive to Italian viruses, indicating that later viruses probably arose within the country and the notion that these later viruses evolved from earlier Italian progenitors cannot be discounted. Biocomputing analysis applied to F and G proteins of later Italian viruses predicted that only G contained altered T cell epitopes. It appears likely that Italian field viruses evolved in response to selection pressure from vaccine induced immunity
Evidence of AMPV attachment protein evolution coincident with mass live vaccine introduction in Italy
No full textAvian metapneumoviruses (AMPV) of subtype B dominate over other subtypes on Italian poultry farms in northern Italy. AMPVs from the Veneto region of Italy between 1987 and 2007 were sequenced in their attachment (G) and fusion (F) protein genes,
together with other subtype B AMPVs from other parts of Western Europe, collected prior to 1994. All viruses in the survey had very similar predicted F sequences whereas the predicted G protein sequences found in Italy from 2001 were distinctly different from those found in pre 1994 viruses. Nonetheless pre 1994 Italian AMPVs were more similar to post 2000 AMPVs than other pre 1994 viruses from other parts of Europe, thereby showing that the later viruses had probably evolved from early Italian viruses. The occurrence of the later variants followed introduction of the mass
administration with a single subtype B vaccine and its G protein sequence placed it clearly in the pre 1994 cluster. The possibility of the vaccine having driven field virus evolution in order to evade immune pressure cannot be excluded
The development of a subtype B AMPV reverse genetics system
No full textA reverse genetics system is the only available method to introduce specific mutations into the AMPV genome. To date no system for the AMPV subtype B had been reported. In the system described, plasmids for N, P, M2, the polymerase and the full genome were constructed under the control of the T7 promoter. Producing intact clones containing the virus polymerase gene proved highly technically demanding due to the issue of them containing sequences toxic to bacteria, thus
leading to sections of the gene being spontaneously deleted. Nonetheless, once all clones had been generated and transfected into Vero cells previously infected with a fowlpox recombinant
virus expressing T polymerase, AMPV was recovered
A comparison of AMPV subtypes A and B full genomes, gene transcripts and proteins led to reverse-genetics systems rescuing both subtypes
No full textAvian metapneumovirus (AMPV) infection of poultry causes serious disease in most countries and subtype A reverse-genetic (RG) systems have allowed a generation of viruses of known sequence, and proved useful in developments towards better control by live vaccines. While subtype B viruses are more prevalent, bacterial cloning issues made subtype B RG systems difficult to establish. A molecular comparison of subtype A and B viruses was undertaken to assess whether subtype A RG components could be partially or fully substituted. AMPV subtype A and B gene-end sequences leading to polyadenylation are, to our knowledge, reported for the first time, as well as several leader and trailer sequences. After comparing these alongside previously reported gene starts and protein sequences, it was concluded that subtype B genome copies would be most likely rescued by a subtype A support system, and this assertion was supported when individual subtype A components were successfully substituted. Application of an advanced cloning plasmid permitted eventual completion of a fully subtype B RG system, and proved that all subtype-specific components could be freely exchanged between A and B systems
1955 Jay-Cee-An BJC - Page 59
No full textPhotographs of the BJC Spanish clubBe Jota Ce- anos
J. Field, Treasurer; D. Koon, Student
Council Representative; D. Vanderplas,
President: R. Gannon, Advisor; G.
Koon, vice- president \ H. Steinbrueck,
Secretary.
G. Bruhjell, S. Kramer, M.
Greenwood, L. Hughes, D.
Hoffman, C. Owen, P.
Knott, S. Eck, K. Bair,
D. Isaak, S. Towne, J.
Berger, S. McDonald, M.
Stee, V. Barrett, D. Ander-son,
H. Shattuck, R. Smith,
E. Ely, D. Arten, C.
Duppong, E. Mi/ ler, G.
Smith, R. Walz, R. Myster,
R. Sundby, H. Munson.
Breaking the Pinata
! Saludos Amigos! EI Club espanol de B. J. C.
es para cultura aeneral en espa~ ol. EI Club
conviene cada meso Hay cines, canciones,
discursos.
Todos los alumnos de espd? rol son miembros
del club. A la Navidad la close tiene una
fiesta con una pinata.
- 59
Status of native species in threatened Mediterranean habitats: The case of Pancratium maritimum L. (sea daffodil) in Lebanon
No full textThe Mediterranean coast of Lebanon is being destroyed by urban expansion and other human activities. Coastal vegetation communities, especially those on prime tourist areas, such as sandy beaches, are under particular threat. This study investigated a native coastal species, Pancratium maritimum L. (Amaryllidaceae), to contribute to knowledge of these highly threatened habitats and investigate possible strategies for their conservation. Ecogeographic surveys, population dynamics and molecular analysis were undertaken. Individual populations occupied areas ranging from 704 and 32,000 m 2 and differed in their structure and reproductive ability. Clump density ranged between 0.002 to 5.6 clumps m -2. Percent fecundity varied significantly between populations and ranged between 0.07 and 57.4percent. In contrast, seedling recruitment and survival were consistently nil or low in all populations. The average Nei's unbiased genetic identity based on RAPD data was 0.09, suggesting that the species is self-pollinated. Cluster analysis indicated that populations did not group according to geographic proximity. F statistics revealed higher variation within than between populations. According to IUCN Red List Criteria at the Regional Level the current status of P. maritimum in Lebanon is Vulnerable [VU B1ab (i,ii,iii,iv,v)+2ab (i,ii,iii,iv,v)]. This could rapidly move to a higher category of threat unless conservation measures are adopted very quickly. © 2004 Elsevier Ltd. All rights reserved.Anderberg M.R., 1973, CLUSTER ANAL APPL; Bartish IV, 1999, MOL ECOL, V8, P791, DOI 10.1046-j.1365-294X.1999.00631.x; Blamey M., 1993, MEDITERRANEAN WILD F; BRYAN JE, 1989, BULBS, V1; DARDAS M, 2000, THESIS AM U BEIRUT; DAVIS PH, 1984, FLORA TURKEY E AEGAE, V8; Dothan N.F., 1986, FLORA PALAESTINA, V4; Gardenfors U, 2001, CONSERV BIOL, V15, P1206, DOI 10.1046-j.1523-1739.2001.00112.x; *IUCN, 1994, PARK LIFE ACTION PRO; IUCN (International Union for the Conservation of Nature), 2001, IUCN RED LIST CAT CR; Kent M, 1992, VEGETATION DESCRIPTI; Medrano M, 1999, FLORA, V194, P13; Meikle R. D., 1985, FLORA CYPRUS; *MIN ENV, 1966, MOE LEDO; MOUTERDE P, 1966, FLORE LIBAN SYRIE, V1; *NAT BIOD STUD ACT, 1998, REP LEB MIN ENV; NEHME M, 1977, FLEURS SAUVAGE LIBN, P240; POST G, 1933, FLORA SYRIA, V2; SNEATH PHA, 1973, NUMERICAL TAX; SPSS inc, 2001, SPSS WIND REL 11 0 0; STURTEVANT EL, 1919, STURTEVANTS NOTES ED; TACKHOLM V, 1954, FLORA EGYPT, V3, P94; *UNEP, 1996, BIOL DIVERSITY LEBAN, V9; WILLIAMS JGK, 1990, NUCLEIC ACIDS RES, V18, P6531, DOI 10.1093-nar-18.22.6531; ZOHARY M., 1982, PLANTS BIBLE13131
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