General Medicine

A novel actinomycete that was capable of degrading poly(l-lactic acid), strain CMU-PLA07T, was isolated from soil in northern Thailand. Strain CMU-PLA07T had biochemical, chemotaxonomic, morphological and physiological properties that were consistent with its classification in the genus Amycolatopsis. 16S rRNA gene sequence analysis showed that the isolate formed a phyletic line within the genus Amycolatopsis. Strain CMU-PLA07T was most similar to Amycolatopsis coloradensis IMSNU 22096T (99.5 % 16S rRNA gene sequence similarity) and Amycolatopsis alba DSM 44262T (99.4 %). However, strain CMU-PLA07T was distinguishable from the type strains of species of the genus Amycolatopsis on the basis of DNA–DNA relatedness and phenotypic data. Therefore, strain CMU-PLA07T is considered to represent a novel species of the genus Amycolatopsis, for which the name Amycolatopsis thailandensis sp. nov. is proposed. The type strain is CMU-PLA07T ( = JCM 16380T = BCC 38279T).

A thermotolerant, Gram-stain-positive, aerobic, sporangium-forming actinomycete, strain RA45T, was isolated from a desert region in Xinjiang Uigur Autonomous Region, north-western China. Comparative analysis of the 16S rRNA gene sequence and phenotypic characterization revealed that strain RA45Tbelonged phylogenetically to the familyPseudonocardiaceaeof the suborderPseudonocardineae. Strain RA45Tshowed more than 5 % 16S rRNA gene sequence divergence from recognized species of genera in the familyPseudonocardiaceae, forming a distinct lineage within the evolutionary radiation occupied by the generaAmycolatopsis,Prauserella,Thermocrispum,Saccharomonospora,SaccharopolysporaandSciscionella, but distinct from each of them. The affiliation to the family was supported by the presence of suborder- and family-specific 16S rRNA signature nucleotides, a DNA G+C content of 69.9 mol%, the presence ofmeso-diaminopimelic acid, ribose, arabinose, glucose and galactose, which are characteristic components of cell-wall chemotype IV of actinomycetes, the presence of menaquinone MK-9(H4) as the major respiratory lipoquinone, a lack of mycolic acids and the presence of anN-acetylated type of muramic acid. However, strain RA45Tdiffered from known genera of the family in its polar lipid composition: the major phospholipids were phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylmethylethanolamine, diphosphatidylglycerol, phospholipids of unknown structure and phospholipids of unknown structure containing glucosamine (phospholipid type IV). Based on its morphological, chemotaxonomic and phylogenetic characteristics, strain RA45Tis considered to represent a novel species of a new genus in the familyPseudonocardiaceae, for which the nameYuhushiella desertigen. nov., sp. nov. is proposed. The type strain ofYuhushiella desertiis RA45T(=CGMCC 4.5579T=JCM 16584T).

AbstractBACKGROUND: Vector‐borne plant disease management can be enhanced by deployment of antifeedants in addition to the use of broad‐spectrum neurotoxic insecticides. The effects of pymetrozine on Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, feeding behaviour, survival and transmission of Candidatus Liberibacter asiaticus (Las), the presumed causal pathogen of huanglongbing, were investigated.RESULTS: Pymetrozine applied at 52 and 104 µg mL−1 to citrus plants [Swingle citrumelo (X Citroncirus webberi Ingram and Moore)] modified the feeding behavior of ACP and increased the amount of time spent performing non‐penetration behaviors while decreasing the time spent performing ingestion behaviors compared with the controls 1 day after treatment. However, the antifeedant effect of pymetrozine subsided 5 days after application. Pymetrozine reduced the survival of both adults and nymphs on treated plants compared with the control. However, it had a greater impact on survival of nymphs than on survival of adults. Pymetrozine applied at 52 and 104 µg mL−1 on Las‐infected ‘Valencia’ sweet orange plants [Citrus sinensis L. (Osbeck)] reduced acquisition (12 and 21% respectively) and transmission (11 and 18% respectively) of Las by feeding ACP adults compared with the controls; however, these reductions were not statistically significant.CONCLUSIONS: Pymetrozine exhibited moderate antifeedant effects by modifying the feeding behavior of ACP adults with short residual activity. The impact of pymetrozine on survival of nymphs was greater than on adults at the higher concentrations tested. Pymetrozine also reduced the acquisition and transmission of Las by feeding ACP adults up to 21 and 18%, respectively, compared with untreated controls. Copyright © 2010 Society of Chemical Industry

AbstractBACKGROUND: In the present investigation, the effect of Candidatus Liberibacter asiaticus (Las), a bacterium considered to be responsible for causing huanglongbing (HLB) disease in citrus, on the physiology of its vector, the Asian citrus psyllid (ACP) Diaphorina citri Kuwayama, was determined. Specifically, the effects of Las infection on the susceptibility of ACP to selected insecticides were determined. Furthermore, total protein content and general esterase activity were quantified in Las‐infected and uninfected ACP to gain insight into the possible mechanism(s) responsible for altered susceptibility to insecticides owing to Las infection.RESULTS: LC50 values were significantly lower in Las‐infected than in uninfected ACP adults for chlorpyrifos and spinetoram. Furthermore, there was a general trend towards lower LC50 values for three other insecticides for Las‐infected ACP; however, the differences were not statistically significant. Total protein content (µg mL−1) was significantly lower in Las‐infected (23.5 ± 1.3 in head + thorax; 27.7 ± 1.9 in abdomen) than in uninfected (29.7 ± 2.1 in head + thorax; 35.0 ± 2.3 in abdomen) ACP. Likewise, general esterase enzyme activity (nmol min−1 mg−1 protein) was significantly lower in Las‐infected (111.6 ± 4.5 in head + thorax; 109.5 ± 3.7 in abdomen) than in uninfected (135.9 ± 7.5 in head + thorax; 206.1 ± 23.7 in abdomen) ACP.CONCLUSION: Susceptibility of ACP to selected insecticides from five major chemistries was greater in Las‐infected than in uninfected ACP. The lower total protein content and reduced general esterase activity in Las‐infected than in uninfected ACP may partly explain the observed higher insecticide susceptibility of Las‐infected ACP. Copyright © 2010 Society of Chemical Industry