Elevated Esterases Exhibiting Arylesterase-like Characteristics in an Organophosphate-Resistant Clone of the Greenbug, Schizaphis graminum (Homoptera: Aphididae)

2000 ◽  
Vol 67 (3) ◽  
pp. 155-167 ◽  
Author(s):  
Kun Yan Zhu ◽  
Fengqin He
Keyword(s):  
Schizaphis Graminum ◽  
Resistant Clone

scholarly journals In vitro activities of novel catecholate siderophores against Plasmodium falciparum.

1996 ◽  
Vol 40 (9) ◽  
pp. 2094-2098 ◽  
Author(s):  
B Pradines ◽  
F Ramiandrasoa ◽  
L K Basco ◽  
L Bricard ◽  
G Kunesch ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Mechanism Of Action ◽  
Ribonucleotide Reductase ◽  
Antimalarial Activity ◽  
Iron Chelators ◽  
Resistant Clone ◽  
Iron Deprivation ◽  
Level Of Activity ◽  
Susceptible Clone

The activities of novel iron chelators, alone and in combination with chloroquine, quinine, or artemether, were evaluated in vitro against susceptible and resistant clones of Plasmodium falciparum with a semimicroassay system. N4-nonyl,N1,N8-bis(2,3-dihydroxybenzoyl) spermidine hydrobromide (compound 7) demonstrated the highest level of activity: 170 nM against a chloroquine-susceptible clone and 1 microM against a chloroquine-resistant clone (50% inhibitory concentrations). Compounds 6, 8, and 10 showed antimalarial activity with 50% inhibitory concentrations of about 1 microM. Compound 7 had no effect on the activities of chloroquine, quinine, and artemether against either clone, and compound 8 did not enhance the schizontocidal action of either chloroquine or quinine against the chloroquine-resistant clone. The incubation of compound 7 with FeCI3 suppressed or decreased the in vitro antimalarial activity of compound 7, while no effect was observed with incubation of compound 7 with CuSO4 and ZnSO4. These results suggest that iron deprivation may be the main mechanism of action of compound 7 against the malarial parasites. Chelator compounds 7 and 8 primarily affected trophozoite stages, probably by influencing the activity of ribonucleotide reductase, and thus inhibiting DNA synthesis.

Annual variation in strains of barley yellow dwarf virus in Manitoba, and the occurrence of greenbug-specific isolates

1969 ◽  
Vol 47 (8) ◽  
pp. 1277-1283 ◽  
Author(s):  
C. C. Gill
Keyword(s):  
Annual Variation ◽  
Barley Yellow Dwarf Virus ◽  
Rhopalosiphum Padi ◽  
Schizaphis Graminum ◽  
Yellow Dwarf ◽  
Dwarf Virus ◽  
Barley Yellow Dwarf ◽  
Efficient Vector ◽  
Yellow Dwarf Virus ◽  
High Degree

Seventeen isolates of the aphid-borne barley yellow dwarf virus (BYDV), collected in southern Manitoba in 1966, were transmitted from oats to oats most efficiently by Rhopalosiphum padi. They were transmitted also by Macrosiphum avenae and all but two were transmitted by Schizaphis graminum and Acyrthosiphon dirhodum. Most of these isolates were not transmitted by R. maidis.Only 3 of 25 isolates collected in 1967 were transmitted by the five species of aphids in a pattern similar to that of the isolates collected in 1966. Twenty of the remainder were transmitted with a moderate to high degree of specificity by R. maidis, R. padi, or S. graminum. Two of the latter isolates were transmitted only by S. graminum. When the transmissibility of one of the isolates, for which S. graminum was the most efficient vector, was examined more critically, both the relative and the specific efficiency of the three vectors varied with the age of the infection in the source plants, though S. graminum was always the most efficient vector.

scholarly journals Investigation of an outbreak of ciprofloxacin-resistant Neisseria gonorrhoeae using a simplified opa-typing method

2001 ◽  
Vol 126 (2) ◽  
pp. 219-224 ◽  
Author(s):  
H. M. PALMER ◽  
J. P. LEEMING ◽  
A. TURNER
Keyword(s):  
United Kingdom ◽  
Neisseria Gonorrhoeae ◽  
Significant Problem ◽  
Resistant Clone ◽  
Typing Method ◽  
Antibiotic Resistant ◽  
The North ◽  
The United Kingdom ◽  
South Wales ◽  
Pcr Rflp

Ciprofloxacin-resistant gonococci have been isolated from patients in the United Kingdom since 1993. Until recently, evidence has suggested that the majority of infections are not endemic but have been acquired abroad. In October 1999, increasing numbers of ciprofloxacin resistant isolates of the non-requiring auxotype were reported in Oldham and Rochdale (Northwest England). These and similar isolates from elsewhere in England and Wales were genetically characterized using a simplified opa-typing method (a non-radioactive PCR–RFLP method targeting the opa family of genes). Of 73 isolates studied, 24 had unique opa-types (10 from infections acquired abroad), whilst the remaining 49 were indistinguishable (none were known to be acquired abroad). This cluster included 31 isolates from Oldham and Rochdale, 16 from elsewhere in the north of England, and 2 from Southern England and South Wales with known epidemiological links to cases from Manchester and Rochdale respectively. This study illustrates the potential for spread of an antibiotic resistant clone of N. gonorrhoeae both locally and nationally and demonstrates that endemic acquisition of ciprofloxacin-resistant gonococci is now a significant problem in the United Kingdom.

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