Antibacterial spectrum of Hypericum hookerianum.

The antibacterial activity of the chloroform, acetone and methanol extracts of Hypericum hookerianum leaves and stems was evaluated. All extracts showed antibacterial activity against six different gram-positive and gram-negative bacteria, the methanol extracts exhibiting the maximum inhibitory activity at 400 microg/ml.     

Comparative performance of four multi-purpose trees associated with four grass species in the humid regions of Southern India

The results of a field trial conducted at the Livestock Research Station, Thiruvazhamkunnu, Kerala to study the compatibility of different components in a silvo-pastoral system revealed that growth and yield of fodder species were significantly influenced by the tree components only after tree canopy formation. The fodder species such as Pennisetum purpureum Schum., Panicum maximum Jacq., Brachiaria ruziziensis Griseb. and Euchlaena mexicana Schrad. grown in association with Casuarina equisetifolia J. R. & G. Forst. and Ailanthus malabarica DC recorded comparatively higher forage yield even after canopy formation. However, forage crops grown in combination with Acacia auriculiformis A. Cunn. ex Benth. and Leucaena leucocephala (Lam.) de Wit. registered relatively lower values for growth and yield. Increased light infiltration into the understorey due to the cladophyllous canopy can be attributed as reason for the higher fodder productivity under Casuarina. Due to the combination of crown size and shape, tree height and spacing the amount of light intercepted by Ailanthus also was very low. Among the four multi-purpose trees used, Acacia recorded the maximum growth rate followed by Casuarina, Ailanthus and Leucaena. Forage productivity of the four species was in the order: Pennisetum purpureum > Panicum maximum > Brachiaria ruziziensis > Euchlaena mexicana. Casuarina with Pennisetum/ Panicm were found to be optimal tree — forage combinations for silvo-pastoral systems.     

Anxiolytic activity of aerial and underground parts of Passiflora incarnata

The petroleum ether, chloroform, methanol, and water extracts of Passiflora incarnata whole plant and sorted out plant parts have been evaluated for their anxiolytic activity using the elevated plus-maze model in mice. The methanol extracts of leaves, stems, flowers, and whole plant exhibited anxiolytic effects at 100, 125, 200 and 300 mg/kg, respectively. The roots were practically devoid of anxiolytic effects. These results show that roots and flowers of P. incarnata act as natural adulterants by causing a significant increase in the anxiolytic dose. Therefore, separation of these parts is recommended prior to any pharmacological, phytochemical and standardization studies on P. incarnata.     

Thinning,fertilization, and crown position interact to control physiological responses of loblolly pine

To examine physiological responses to thinning, fertilization, and crown position, we measured net photosynthesis (P(n)), transpiration (E), vapor pressure difference (VPD), stomatal conductance (g(s)), and xylem pressure potential (Psi(1)) between 0930 and 1130 h under ambient conditions in the upper and lower crowns of a 13-year-old loblolly pine (Pinus taeda L.) plantation six years (1994) after the treatments were applied. Photosynthetic photon flux density (PPFD) and air temperature (T(a)) within the canopy were also recorded. Needle P(n) of thinned trees was significantly enhanced by 22-54% in the lower crown, because canopy PPFD increased by 28-52%. Lower crown foliage of thinned plots also had higher E and g(s) than foliage of unthinned plots, but thinning had no effect on needle Psi(1) and predawn xylem pressure potential (0430-0530 h; Psi(pd)). Tree water status did not limit P(n), E and g(s) during the late-morning measurements. Fertilization significantly decreased within-canopy PPFD and T(a). Needle Psi(1) was increased in fertilized stands, whereas P(n), E and g(s) were not significantly altered. Upper crown foliage had significantly greater PPFD, P(n), VPD, g(s), E, and more negative Psi(1) than lower crown foliage. In both crown positions, needle P(n) was closely related to g(s), PPFD and T(a) (R(2) = 0.77 for the upper crown and 0.82 for the lower crown). We conclude that (1) silvicultural manipulation causes microclimate changes within the crowns of large trees, and (2) needle physiology adjusts to the within-crown environmental conditions.     

Fodder grass productivity and soil fertility changes under four grass+tree associations in Kerala, India

Adapted tree+grass combinations make a valuable contribution to forage production in the Indian peninsula, but knowledge of the interactive effects between trees and grasses on their production is limited. We, therefore, conducted a field experiment involving combinations of four trees and grasses, besides monospecific grass controls, for seven years, to investigate grass productivity in association with leguminous and non-leguminous multipurpose trees (MPT) having disparate canopy architecture, and to assess the end-of-rotation soil fertility changes. Post rotation changes in herbage productivity were evaluated by growing teosinte (Zea mexicana) for three years. The four MPTs were Acacia auriculiformis, Ailanthus triphysa, Casuarina equisetifolia and Leucaena leucocephala. Grasses included Pennisetum purpureum (hybrid napier), Brachiaria ruziziensis (congo signal), Panicum maximum (guinea grass) and teosinte. Lower tree branches were pruned from fifth year. Understorey herbage production increased until three years in all tree+grass combinations, but declined subsequently, as tree crowns expanded. Overall, casuarina among MPTs, and hybrid napier and guinea grass among forage crops, were more productive than others. Pruning MPTs generally favoured greater herbage production. Understorey light levels for acacia, ailanthus, casuarina and leucaena were 17, 60, 55 and 55% of that in the open at five years. During the post-rotation phase, MPT plots were characterised by higher soil nutrient capital and consequently teosinte yields were higher than in the treeless control treatment. All previous tree-grass combinations showed an increasing trend till two years after MPT felling. Yield levels declined subsequently, despite at variable rates. Careful selection of the tree and grass components is, therefore, crucial for optimising herbage productivity in silvopastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.     

Clovis age Western Stemmed projectile points and human coprolites at the Paisley Caves

The Paisley Caves in Oregon record the oldest directly dated human remains (DNA) in the Western Hemisphere. More than 100 high-precision radiocarbon dates show that deposits containing artifacts and coprolites ranging in age from 12,450 to 2295 (14)C years ago are well stratified. Western Stemmed projectile points were recovered in deposits dated to 11,070 to 11,340 (14)C years ago, a time contemporaneous with or preceding the Clovis technology. There is no evidence of diagnostic Clovis technology at the site. These two distinct technologies were parallel developments, not the product of a unilinear technological evolution. "Blind testing" analysis of coprolites by an independent laboratory confirms the presence of human DNA in specimens of pre-Clovis age. The colonization of the Americas involved multiple technologically divergent, and possibly genetically divergent, founding groups.     

Pathotypic and molecular characterization of a fowl adenovirus associated with inclusion body hepatitis in Saskatchewan chickens

Inclusion body hepatitis (IBH) is one of the major global disease problems, causing significant economic losses to poultry industry of the United States and Canada. The disease is characterized by its sudden onset and high mortalities. Amongst different serotypes of fowl adenoviruses (FAdVs) associated with IBH, serotype 8 of group I FAdV has been isolated from majority of IBH cases. In present studies, we isolated a FAdV from morbid liver of a 17-day-old broiler from a Saskatchewan broiler farm. This newly isolated virus was designated as IBHV(SK). However, based on the sequence analysis of the L1 region of the hexon gene, the IBHV(SK) may be classified as FAdV 8b strain 764. These studies describe for the first time the complete hexon gene sequence of FAdV serotype 8b. Experimental infection of 2-day-old (n = 48) and 2-wk-old (n = 56) chicks caused 83% and 43% mortalities, respectively. Determination of the complete hexon gene sequence of IBHV(SK) with establishment of a disease model in chickens will facilitate the development of type-specific diagnostic reagents and assays for the evaluation of potential experimental vaccines against pathogenic FAdV infections.     

Landscape filtering of hydrologic and biogeochemical responses in managed catchments

Here, we examine hydrologic and biogeochemical responses of managed catchments regarding the degree of stochastic, nonlinear filtering of hydro-climatic and anthropogenic drivers. We utilize three types of analyses to examine the time-series records of catchment responses: (1) statistical analysis, based on probability distribution functions (pdfs); (2) temporal Lorenz inequality, based on Gini coefficients, and (3) contingency or memory assessment, based on spectral analysis. We present analytical expressions for pdfs and statistical moments for several catchment responses, explicitly linking stochasticity of drivers and catchment filtering properties. We also examine relative temporal inequality of two catchment signals: Φ _G  = G ₂/G ₁, where G _i is the Gini coefficient of each signal. We use spectral analysis to evaluate the relative memory of two signals: Φ _α  = α ₂/α ₁, where α _i is the slope of spectral power versus frequency of each signal in log–log plots. We use these metrics to evaluate: (1) filtering of precipitation (P) inputs to discharge (Q) outputs from four locations in different moisture regimes in the US, and identify human impacts on catchment hydrology; and (2) dominance of hydrologic variability for nitrate wet deposition flux (Ω) patterns for nine US urban sites, and in the patterns of exported solute loads in intensively managed catchments. Our analyses of long-term monitoring in selected managed catchments suggests that increasing human impacts on landscapes: (1) cause hydrologic and biogeochemical processes to exhibit increasing functional homogeneity; (2) contribute to shifts in memory between catchment drivers and responses; and (3) decrease the temporal inequality of nutrient export dynamics.     

Components of resistance to late leaf spot and rust among interspecific derivatives and their significance in a foliar disease resistance breeding in groundnut (Arachis hypogaea L.)

Late leaf spot (LLS) and rust cause substantial yield losses and reduce the fodder and seed quality in groundnut (Arachis hypogaea L.). Adoption of resistant cultivars by the semi-arid tropic farmers is the best option to overcome yield losses. Knowledge on components of resistance to these diseases should facilitate the development of groundnut cultivars with enhanced resistance to LLS and rust. The objectives of the experiments were to study the genetic variability and relationships among components of resistance to LLS and rust, and assess their significance in disease resistance breeding. Fifteen interspecific derivatives for LLS and 14 for rust and a susceptible control, TMV 2, were evaluated in a randomised complete block design with two or three replications under greenhouse conditions. The experiments were repeated twice. Genotypic differences were highly significant for all the traits studied. Resistance to LLS is due to longer incubation and latent periods, lesser lesions per leaf, smaller lesion diameter, lower sporulation index, and lesser leaf area damage and disease score. Selection based on components of resistance to LLS may not lead to plants with higher retained green leaf area. The remaining green leaf area on the plant should, therefore, be the major selection criteria for resistance to LLS in breeding programs. Resistance to rust is due to longer incubation and latent periods, fewer pustules per leaf, smaller pustule diameter, lower sporulation index, and lesser leaf area damage and disease score. Rust resistant components appear to work additively, therefore, selection based on resistance components together with green leaf area retained on the plant should be the basis of selecting for resistance to rust in breeding programs. ICGV 99005, 99003, 99012, and 99015 for rust and ICGV 99006, 99013, 99004, 99003, and 99001 for LLS are the better parents for use in resistance breeding programs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Purification and Characterization of the Aetiological Agent of Hydropericardium Hepatitis Syndrome from Infected Liver Tissues of Broiler Chickens

Hydropericardium hepatitis syndrome in broiler chickens is an acute, infectious disease characterized by high mortality, excess pericardial fluid and multifocal hepatic necrosis. The aetiological agent was purified to homogeneity from infected liver tissues from field outbreaks. Electron-microscopic and serological confirmation of the virus were undertaken and the disease was reproduced experimentally in broiler chicks. The results indicated that an adenovirus, fowl adenovirus serotype 4, was alone responsible for the disease in the materials studied.