Production of monoclonal antibodies to Tomato leaf curl Bangalore virus

Purified Tomato leaf curl Bangalore virus (ToLCBV) was injected into mice and the splenocytes were used for establishing hybridoma lines. Initial screening of culture supernatants showed that 13 lines produced antibody, and after further screening four produced functional monoclonal antibodies. Upon characterisation, these were found to be of low affinity, probably due to host protein contamination and poor yield of native virus in the original preparations. In order to circumvent these problems, the coat protein of ToLCBV was over-expressed in Escherichia coli. Fusion experiments using recombinant coat protein as antigen yielded two primary hybridoma clones G₁₁ and E4 that exhibited good affinity of binding to the antigen. Sub-cloning yielded four monoclonal antibodies G₁₁E₇E₇, G₁₁E₇G₁₂, E₄E₂ and E₄G₆. G₁₁E₇E₇ and G₁₁E₇G₁₂ successfully detected ToLCBV in infected leaf extracts of tomato and Nicotiana benthamiana, viruliferous whiteflies and weed samples. These monoclonal antibodies could also detect other type III geminiviruses such as Pumpkin yellow vein mosaic virus and Bhendi yellow vein mosaic virus. Thus these monoclonal antibodies can be used for testing field-collected samples.     

Sequences of feeding,sampling and exploration by wild and laboratory rats

Adult male wild rats and male laboratory rats, all Rattus norvegicus, were kept alone for 11 d is a residential maze. The maze had a central nest box and four arms radiating from it. Movement in the arms was automatically recorded. Three foods were supplied, one at the end of each of three arms; the fourth arm was empty. One food was usually much preferred to the othe two. Except on Days 1—3, access to the arms was for only 3h daily.The rate of visiting the arms declined during the first 3 d. The wild rats were more ‘active’ than the domestic in that they made more visits; but they spent less time in the arms. Visits were of two kinds: (a) short, usually < 1min; (b) long (> 4 min.: meals). The wild rats had shorter meals than the donestic.A 3-h period of access usually began with a bout of short visits to the arms. Each long visit to a food arm (a meal) was also typically followed by such a bout, sometimes after a period in the nest box (drinking). the first short visit after a meal by a wild rat was most often to the empty arm; but domestic rats distributed these visits evenly among the three arms in which they had not been feeding. In a given bout the second short visit by a wild rat, but not a domestic, tended to repeat the first.We interpret a bout of short visits as a patrol or re-exploration of the living space which may include sampling of all accessible foods. When a bout occured at the beginning of access to the maze arms, exploring was in ‘competition’ with eating; a bout after a meal may have represented ‘disinhibition’ of exploring.     

Urbanization alters the spatiotemporal dynamics of plant–pollinator networks in a tropical megacity

Urbanization is a major driver of biodiversity change but how it interacts with spatial and temporal gradients to influence the dynamics of plant–pollinator networks is poorly understood, especially in tropical urbanization hotspots. Here, we analysed the drivers of environmental, spatial and temporal turnover of plant–pollinator interactions (interaction β-diversity) along an urbanization gradient in Bengaluru, a South Indian megacity. The compositional turnover of plant–pollinator interactions differed more between seasons and with local urbanization intensity than with spatial distance, suggesting that seasonality and environmental filtering were more important than dispersal limitation for explaining plant–pollinator interaction β-diversity. Furthermore, urbanization amplified the seasonal dynamics of plant–pollinator interactions, with stronger temporal turnover in urban compared to rural sites, driven by greater turnover of native non-crop plant species (not managed by people). Our study demonstrates that environmental, spatial and temporal gradients interact to shape the dynamics of plant–pollinator networks and urbanization can strongly amplify these dynamics.