Impaired B and T cell antigen receptor signaling in p110delta PI 3-kinase mutant mice

Class IA phosphoinositide 3-kinases (PI3Ks) are a family of p85/p110 heterodimeric lipid kinases that generate second messenger signals downstream of tyrosine kinases, thereby controlling cell metabolism, growth, proliferation, differentiation, motility, and survival. Mammals express three class IA catalytic subunits: p110alpha, p110beta, and p110delta. It is unclear to what extent these p110 isoforms have overlapping or distinct biological roles. Mice expressing a catalytically inactive form of p110delta (p110delta(D910A)) were generated by gene targeting. Antigen receptor signaling in B and T cells was impaired and immune responses in vivo were attenuated in p110delta mutant mice. They also developed inflammatory bowel disease. These results reveal a selective role for p110delta in immunity.     

Daily oviposition patterns of the African malaria mosquito <Emphasis Type="Italic">Anopheles gambiae</Emphasis> Giles (Diptera: Culicidae) on different types of aqueous substrates

Background  

Anopheles gambiae Giles is the most important vector of human malaria in sub-Saharan Africa. Knowledge of the factors that influence its daily oviposition pattern is crucial if field interventions targeting gravid females are to be successful. This laboratory study investigated the effect of oviposition substrate and time of blood feeding on daily oviposition patterns of An. gambiae mosquitoes.     

Monitoring of Brazilian wheat blast field populations reveals resistance to QoI,DMI, and SDHI fungicides

Wheat blast is one of the most important and devastating fungal diseases of wheat in South America, South-east Asia, and now in southern Africa. The disease can reduce grain yield by up to 70% and is best controlled using integrated disease management strategies. The difficulty in disease management is compounded by the lack of durable host resistance and the ineffectiveness of fungicide sprays. New succinate dehydrogenase inhibitor (SDHI) fungicides were recently introduced for the management of wheat diseases. Brazilian field populations of the wheat blast pathogen Pyricularia oryzae Triticum lineage (PoTl) sampled from different geographical regions in 2012 and 2018 were shown to be resistant to both QoI (strobilurin) and DMI (azole) fungicides. The main objective of the current study was to determine the SDHI baseline sensitivity in these populations. Moderate levels of SDHI resistance were detected in five out of the six field populations sampled in 2012 and in most of the strains isolated in 2018. No association was found between target site mutations in the sdhB, sdhC, and sdhD genes and the levels of SDHI resistance, indicating that a pre-existing resistance mechanism not associated with target site mutations is probably present in Brazilian wheat blast populations.     

Losartan, an AT1 antagonist, prevents aortic aneurysm in a mouse model of Marfan syndrome

Aortic aneurysm and dissection are manifestations of Marfan syndrome (MFS), a disorder caused by mutations in the gene that encodes fibrillin-1. Selected manifestations of MFS reflect excessive signaling by the transforming growth factor-beta (TGF-beta) family of cytokines. We show that aortic aneurysm in a mouse model of MFS is associated with increased TGF-beta signaling and can be prevented by TGF-beta antagonists such as TGF-beta-neutralizing antibody or the angiotensin II type 1 receptor (AT1) blocker, losartan. AT1 antagonism also partially reversed noncardiovascular manifestations of MFS, including impaired alveolar septation. These data suggest that losartan, a drug already in clinical use for hypertension, merits investigation as a therapeutic strategy for patients with MFS and has the potential to prevent the major life-threatening manifestation of this disorder.     

Development of a method for detection of latent European fruit tree canker (<Emphasis Type="Italic">Neonectria ditissima</Emphasis>) infections in apple and pear nurseries

Fruit tree canker caused by Neonectria ditissima is a serious problem in apple-producing regions with moderate temperatures and high rainfall throughout the year; especially in northwestern Europe, Chile, and New Zealand. Control measures are applied to protect primary infection sites, mainly leaf scars, from invasion by external inoculum. However, latent infections may occur when young apple trees are infected symptomlessly during propagation. This study aimed to develop a method for detection of latent fruit tree canker infections. Inoculations with conidiospore suspensions of N. ditissima were carried out in tree nurseries on the main stems of two-year-old trees of three apple cultivars and one pear cultivar. The inoculations were carried out during the natural abscission period in the autumn. No visible lesion or canker formations were present at the time when the inoculated trees were uprooted. It appeared that the infections may remain latent during the period from infection to uprooting (2 months) and during the subsequent 4 months of cold storage of the trees. Nevertheless, symptoms were generally induced within 8 weeks after transfer of infecting planting material from the nursery field into a climate chamber with high temperature and high relative humidity. The methodology presented is developed to detect latent infections of N. ditissima in nursery trees, prior to planting in the orchards, and it may contribute in reducing the problem with European fruit tree canker in commercial production.     

Phylogeography and conservation gaps of Musa balbisiana Colla genetic diversity revealed by microsatellite markers

Genetic Resources and Crop Evolution - Collection and storage of crop wild relative (CWR) germplasm is crucial for preserving species genetic diversity and crop improvement. Nevertheless, much of...