Miracle-dz/UniFAR-FTUs huggingface dataset:
MORPHOLOGICAL SPECIALIZATIONS OF THE BUMBLE BEE SOCIAL PARASITE PSITHYRUS ASHTONI (CRESSON) (HYMENOPTERA: APIDAE)

Abstract Psithyrus spp. (Hymenoptera: Apidae) are obligate social parasites of bumble bees (Bombus spp.). Morphological and physiological features of P. ashtoni (Cresson) females, which may facilitate the successful usurpation of host nests, were examined. Parasite females were no larger than B. terricola Kirby queens, although they possessed a number of protective modifications to the exoskeleton, as well as increased offensive armament, including larger mandibles and a longer venom gland. Females of P. ashtoni and P. insularis (Smith) possessed a greater number of ovarioles than host queens, and produced smaller eggs. The Dufour’s glands of the two Psithyrus species were significantly larger than those of B. terricola. There appears to have been considerable convergence in the evolution of socially parasitic lifestyles in bumble bees and wasps (Vespula spp.), presumably as a consequence of similar selective pressures operating on parasites belonging to these distantly related but socially similar taxa. Résumé Les Psithyrus spp. (Hymenoptera : Apidae) sont des parasites sociaux obligatoires des bourdons (Bombus spp.). Les caractéristiques morphologiques et physiologiques des femelles de P. ashtoni (Cresson) qui peuvent favoriser l’usurpation des nids de leurs hôtes ont fait l’objet d’une étude. Les femelles parasites ne sont pas plus grosses que les reines de B. terricola Kirby, mais leur exosquelette comporte plusieurs modifications protectrices et elles possèdent plus d’armes offensives, notamment des mandibules plus grandes et une glande à venim plus longue. Les femelles de P. ashtoni et de P. insularis (Smith) ont aussi un plus grand nombre d’ovarioles que les reines hôtes et produisent des oeufs plus petits. Les glandes de Dufour des deux espèces de Psithyrus sont significativement plus grandes que celles de B. terricola. Il semble y avoir eu beaucoup de convergence dans l’évolution du mode de vie des parasites sociaux chez les bourdons et les quêpes (Vespula spp.), probablement à la suite de pressions de sélection similaires opérées sur des parasites appartenant à des taxons peu apparentés, mais semblables par leur mode de vie social. [Traduit par la rédaction]
The role of VAMP proteins in K+ channel regulation

SNARE (soluble N-ethylmaleimide-sensitive factor protein attachment protein receptor) proteins drive vesicle traffic, delivering membrane and cargo to target sites within the cell and at its surface. They contribute to cell homeostasis, morphogenesis and pathogen defense. A subset of SNAREs, including the Arabidopsis SNARE SYP121, are known also to coordinate solute uptake via physical interactions with K+ channels and to moderate their gating at the plasma membrane. R-SNAREs, also known as vesicle-associated membrane proteins (VAMPs), are most commonly associated with trafficking vesicles. In guard cells of Arabidopsis, ABA-dependent stomatal closure was inhibited when the expression of VAMP71 family genes were suppressed by an antisense VAMP711 construct. Such results reveal that VAMPs play an important role in plant response to stress, especially in the regulation of stomatal closure under ABA treatment. Two R-SNAREs, VAMP721 and VAMP722, are known to assemble in SNARE core complexes with SYP121 and with its closest homolog SYP122, which raises the question whether the channel interaction might extend to the R-SNAREs leading to VAMP regulating channel gating. To answer this question, I investigated the interaction between the VAMP7 proteins with KC1 and KAT1 K+ channels by mating based Split-Ubiquitin System (mbSUS) assay, and verified these interactions by ratiometric bimolecular fluorescence complementation (rBiFC) assay. I found VAMP721 and VAMP722, but not VAMP723, interacted with the channels. The selective binding was associated with the VAMP longin domain, notably with Tyr57. What is the effect of the VAMP-K+ channel interaction on transmembrane ion transport and vesicle traffic? I found VAMP721 affected K+ channel gating and suppressed the K+ current within the physiological voltage range by electrophysiological analysis in Xenopus oocytes and in VAMP over-expression wild type Arabidopsis. The effect of VAMP721 on K+ channel regulation was opposite to the action of SYP121 on K+ channel. From localization, interaction and electrophysiological studies, I was able to show that Tyr57 is a key residue required both for VAMP-dependent gating of the K channels and for localization of the VAMPs at the plasma membrane. For vesicle traffic, I found overexpression of full length VAMP721 in Arabidopsis seedlings blocked the secretion of secYFP while coexpressing with KC1 K+ channel rescued the traffic block, demonstrating a potential action of VAMP-K+ channel interaction on secretory traffic. These results add to understanding the interaction between SNARE and K+ channels that link membrane traffic with osmotically active solute transport in the plant.
Effects of toxins from two strains of Verticillium lecanii (Hyphomycetes) on bioattributes of a predatory ladybeetle, Delphastus catalinae (Col., Coccinellidae)

Abstract: The aim of this study was to test the hypothesis that the whitefly (Bemisia tabaci; Hom., Aleyrodidae) predator ladybird beetles, Delphastus catalinae (Col., Coccinellidae), are not adversely affected in the field by the crude insecticidal toxins extracted from two strains of the fungus Verticillium lecanii, V3450 and Vp28. We developed a method to evaluate sublethal toxicity and its effects on consumption and functional response of D. catalinae. The crude toxins have low toxicity against beetle larva with LC50 values of 1942 (1393–2710) and 2471 (1291–4731) p.p.m. , respectively (approximately 10‐ and 12‐fold of field rate of application 200 p.p.m.). The adult beetles had less sensitivity to crude toxins with LC50 values of 4260 (3376–5375) and 4426 (1734–11298) p.p.m. , respectively (approximately 20‐ and 22‐fold of field rate 200 p.p.m.). The consumption and foraging capacity were significantly impaired especially in the second‐instar larval beetles which took longer time (more than twice of the control beetles) to consume whitefly eggs after exposure to toxins, although D. catalinae suffered no significant effect on fecundity and longevity, when exposed to a toxin dilution of field rate. The data suggest that spraying of V. lecanii or its toxins should be avoided in the field having immature stages of D. catalinae.
Chinook salmon outmigration survival in wet and dry years in California's Sacramento River

Outmigration survival of acoustic-tagged, hatchery-origin, late-fall-run Chinook salmon (Oncorhynchus tshawytscha) smolts from the Sacramento River was estimated for 5 years (2007–2011) using a receiver array spanning the entire outmigration corridor, from the upper river, through the estuary, and into the coastal ocean. The first 4 years of releases occurred during below-average river flows, while the fifth year (2011) occurred during above-average flows. In 2011, overall outmigration survival was two to five times higher than survival in the other 4 years. Regional survival estimates indicate that most of the improved survival seen in 2011 occurred in the riverine reaches of the outmigration corridor, while survival in the brackish portions of the estuary did not significantly differ among the 5 years. For the 4 low-flow years combined, survival rate in the river was lower in the less anthropogenically modified upper reaches; however, across all regions, survival rate was lowest in the brackish portion .
On the Interaction of Seryl‐tRNA Synthetase with tRNASer

By following the tryptophan fluorescence of yeast seryl-tRNA synthetase on additition of tRNASer it was observed that the number of binding sites for tRNA decreases from two to one with increasing temperature, ATP or KCl concentration. Concomitantly a considerable decrease of the apparent binding constant was observed. The variation in the number of binding sites is explained by the presence of at least one temperature and ionic strength sensitive binding site and one temperature and ionic strength independent binding site. Relaxation kinetic experiments revealed two binding processes: a fast one depending on tRNA concentration and ionic strength and a slow one, which appeared to be independent of tRNA concentration and ionic strength. Enzyme kinetic studies showed that the activity of seryl-tRNA synthetase strongly depends on the KCI concentration and exhibits a maximum at 0.2 M KCl. Based on the data from relaxation and enzyme kinetic experiments a model is suggested for the recognition process involving a first unspecific step where all tRNAs, cognate and non-cognate. are bound to the synthetase (scanning step). The identification of the cognate tRNA is then performed at-the recognition site by a conformational transition of the tRNA synthetase complex (identification step)
The fatty acids of neem oil and their reduction products

The seed oil of Melia (Azadirachta) indica has been critically re-examined particularly with reference to fatty acid composition, using the gas chromatograph as a means of analytical control. Behenic acid has been discovered as a component and the presence of myristic acid and lignoceric acid verified. The limitations of some earlier methods of analysis are illustrated. A suitably purified neem oil has been successfully reduced to the corresponding saturated and unsaturated alcohols by a selective sodium reduction procedure of potential industrial value. The reduction products and their acetyl esters have been examined by gas-liquid chromatography. A comparison is made between the results obtained from methyl esters as derivatives and those obtained from the alcohols and their acetates.
Effects of insulin therapy on fracture healing and expression of VEGF in diabetic rats

Summary This study was designed to investigate effects of insulin on fracture healing and expression of vascular endothelial growth factor (VEGF) in diabetic rats. Wister rats were randomly divided into diabetic control (n=66), diabetic insulin (=66) and non-diabetic control group (n=66). Diabetes was established by peritoneal injection of alloxan. Tibia fracture was surgically created and was allowed to heal. Radiological and biomechanical examinations were performed on the healing tibia. Immuohistochemistry was used to assess VEGF expression in the healing fracture tissues. Cortical reconstruction of the fracture sites in non-diabetic control and diabetic insulin groups was more rapid than in diabetic control group within 6 weeks of the fracture. Mechanical strength of the affected tibia in the diabetic insulin and non-diabetic control group was superior to diabetic control group. Histological examination of the fracture sites revealed a delay in chondrocyte maturation and hypertrophy in diabetic control group. VEGF expression was widely distributed in fracture sites within the first 4 weeks in control and diabetic insulin treatment group. However VEGF expression in the callus and periosteum in diabetic control group was much less than in diabetic insulin or non-diabetic control group. In conclusion, diabetes delays fracture healing and adversely affects callus formation with a reduced VEGF expression at the fracture sites. Insulin therapy improves fracture healing in diabetes rats, possibly through enhancing VEGF expression in the fractured bones.
Exploration Of Piliostigma Thonningii (Schum.) A Tropical Tree For Possible Utilization As A Plant-Derived Pesticide

The use of plant-derived pesticides against crop pests both on the field and during post-harvest is now emerging as one of the most important means of crop protection under an Integrated Pest Management framework following the multiple global challenges created by synthetic chemical pesticides. Studies on the phytochemicals, chemomicroscopic screening and mineral composition of Piliostigma thonningii (Schum.) were investigated for its potential useful bioactive compounds resource for possible utilization as plant-derived pesticides.The aqueous screening using reported methodologies for phytochemical screening revealed the presence of alkaloids, anthraquinones, carbohydrates, glycosides, flavonoids, saponins, steroids and tannins. Mineral analysis of both bark and leaves revealed that it contain substantial amount of nutrients evaluated. The results of this study suggested that P. thonningii (Schum.) have great potential as plant-derived pesticidal agent. Knowing that P. thonningii (Schum.) have bioactive properties is not enough, more research work is recommended on the various plant parts for isolation and characterization of bioactive compounds that may be utilize for pest control of agricultural plants. DOI: 10.5901/ajis.2014. v3n7p108
Effect of eggshells for the harvesting of microalgae species

The aim of this study was to determine the optimal conditions for adding eggshells as a bioflocculant (including concentration dosage, pH, mixing time, mixing rate and settling time) in harvesting Chlorella vulgaris cells from liquid cultures, using the well-known jar-test experimental method. Eggshells separated successfully 99 ± 0.4% of the C. vulgaris biomass at the following optimal parameters: eggshell concentration 80 mg/L, mixing time 20 min, mixing rate 150 r/min and settling time 20 min at pH 6. These results indicated that eggshells, as a biopolymer, are a promising flocculant due to their high separation efficiency, low dose requirements and short mixing and settling time. Eggshells not only act as an adsorbent, but also spontaneously coagulate to agglomerate the microalgae cells.
Diversidade e estrutura do componente herbáceo-subarbustivo em vegetação secundária de Floresta Atlântica no Sul do Brasil

A composicao floristica, diversidade e estrutura do componente herbaceo-subarbustivo e suas relacoes com fatores ambientais foram estudados em comunidades secundarias de Floresta Atlântica de Terras Baixas com cinco (5a.) e 20 anos (20a.) de regeneracao natural. Os dados estruturais foram obtidos em 100 e 35 parcelas de 1 m2 nas capoeiras 5a. e 20a. , respectivamente. Foram avaliadas as correlacoes entre o padrao de distribuicao das especies e variaveis ambientais com analise de correspondencia canonica (CCA). A composicao e estrutura do componente herbaceo-subarbustivo das capoeiras apresentaram diferencas significativas. A similaridade floristica entre as capoeiras atingiu 40%. A capoeira 5a. teve 76 especies e diversidade (H’) de 2,305 nats/ind. A maioria das especies era heliofila e poucas ciofilas. A capoeira 20a. teve 34 especies e H’ de 1,961 nats/ind. Nesta capoeira, a maioria das especies era tolerante a sombra em comparacao a capoeira 5a. Embora haja efeitos do esforco amostral na riqueza, as diferencas gerais observadas distinguiram as capoeiras na CCA. A distribuicao das especies mostrou-se associada em parte a densidade de arbustos e arvores, que reflete o sombreamento nos estratos inferiores, a distância de bordas florestais e as condicoes de fertilidade do solo, provavelmente afetadas por diferentes usos feitos no passado.
PHYSIOLOGICAL AND BIOCHEMICAL STUDIES IN PLANT METABOLISM: II. RESPIRATORY ENZYMES IN WHEAT

The kinetics of the malic dehydrogenase in cell-free extracts of wheat seedlings have been studied by the Warburg technique, using methylene blue. The enzyme behaves analogously to the animal enzyme in that it is coenzyme I-linked and its oxidation product, oxalacetic acid, is inhibitory to the reaction. Oxalacetic acid is removed by either a ketone fixative or l(+) glutamic acid, the latter by being involved in a transamination. Cell-free extracts also contain peroxidase and ascorbic acid oxidase, but no phenolases. In embryonic tissue the succinoxidase system, including cytochrome oxidase, is present. Using l(+) glutamic acid to remove oxalacetic acid, ascorbic acid can replace methylene blue and function as a respiratory carrier mobilizing the hydrogen from dihydrocoenzyme I indirectly via a pigment of unknown chemical nature. A proposed carrier system for the wheat plant includes coenzyme I, flavin, pigment, and ascorbic acid. In vitro, the entry of oxygen to the system is catalyzed by ascorbic acid o.
Testing Models: A Key Aspect to Promote Teaching Activities Related to Models and Modelling in Biology Lessons?

This study investigated biology teachers’ (N = 148) understanding of models and modelling (MoMo), their model-related teaching activities and relations between the two. A framework which distinguishes five aspects of MoMo in science (nature of models, multiple models, purpose of models, testing models and changing models) served as a theoretical background. Teachers’ understanding of MoMo was assessed using constructed-response items which were analysed qualitatively based on a coding scheme. The biology teachers mainly expressed a limited understanding of models as copies or idealised depictions used to show or to explain something. Model-related teaching activities were assessed through rating-scale items. The findings propose that models are primarily generated in biology lessons to show or to explain something but are rarely contrasted with other models, evaluated and modified. Significant correlations between teachers’ understanding of the aspect testing models and their intensity of model-related teaching activities were found. This suggests that the aspect testing models is a key aspect of promoting teaching activities related to MoMo in biology lessons. The findings are discussed with respect to relevant literature about MoMo in science education and educational implications are provided.
The ecosystem size and shape dependence of gas transfer velocity versus wind speed relationships in lakes

Air–water diffusive gas flux is commonly determined using measurements of gas concentrations and an estimate of gas transfer velocity (k600) usually derived from wind speed. The great heterogeneity of aquatic systems raises questions about the appropriateness of using a single wind-based model to predict k600 in all aquatic systems. Theoretical considerations suggest that wind speed to k600 relationships should instead be system-specific. Using data collected from aquatic systems of different sizes, we show that k600 is related to fetch and other measures of ecosystem size. Lake area together with wind speed provided the best predictive model of gas transfer velocity and explained 68% of the variability in individual k600 measurements. For a moderate wind speed of 5 m·s−1, predicted k600 varied from 6 cm·h−1 in a small 1 ha lake to over 13 cm·h−1 in a 100 km2 system. Wave height is also shown to be a promising integrative predictor variable. The modulating influence of system size on wind speed – gas tran.
Soil carbon stock and its changes in northern China's grasslands from 1980s to 2000s

Climate warming is likely to accelerate the decomposition of soil organic carbon (SOC) which may lead to an increase of carbon release from soils, and thus provide a positive feedback to climate change. However, SOC dynamics in grassland ecosystems over the past two decades remains controversial. In this study, we estimated the magnitude of SOC stock in northern China's grasslands using 981 soil profiles surveyed from 327 sites across the northern part of the country during 2001–2005. We also examined the changes of SOC stock by comparing current measurements with historical records of 275 soil profiles derived from China's National Soil Inventory during the 1980s. Our results showed that, SOC stock in the upper 30 cm in northern China's grasslands was estimated to be 10.5 Pg C (1 Pg=1015 g), with an average density (carbon stock per area) of 5.3 kg C m−2. SOC density (SOCD) did not show significant association with mean annual temperature, but was positively correlated with mean annual precipitation. SOCD increased with soil moisture and reached a plateau when soil moisture was above 30%. Site‐level comparison indicated that grassland SOC stock did not change significantly over the past two decades, with a change of 0.08 kg C m−2, ranging from −0.30 to 0.46 kg C m−2 at 95% confidence interval. Transect‐scale comparison confirmed that grassland SOC stock remained relatively constant from 1980s to 2000s, suggesting that soils in northern China's grasslands have been carbon neutral over the last 20 years.
Sampling Bees (Hymenoptera: Apiformes) for Pollinator Community Studies: Pitfalls of Pan-trapping

With the growing interest in pollinator conservation, a need has emerged for a simple, unbiased method to reliably sample local bee faunas. One method, pan-trapping, has increased in popularity without critical evaluation of its efficacy and biases. We compared traditional net collecting at flowers and pan trapping concurrently, sampling the local bee fauna of the dominant desert shrub, creosote bush (Larrea tridentata) growing at the Silver bell site of the International Biosphere Program (IBP) nw of Tucson Arizona. Pan-traps on the ground yielded a faunal sample depauperate in many of the more common native bee species on creosote bush, particularly its floral specialists. This pan-trap sample also corre sponded poorly with the previous four years' faunal samples at this site, with pairs of neigh boring net-sampled sites throughout the Southwest, and with all pairs of bee samples from Larrea across the Upper Sonoran desert. The likely causes of this disparity and the utility of pan trapping for bees in faunal and community studies is discussed.
Diversity regulation at macro-scales: species richness on oceanic archipelagos

Aim Understanding the mechanisms that generate diversity patterns requires analyses at spatial and temporal scales that are appropriate to the dispersal capacities and ecological requirements of organisms. Oceanic archipelagos provide a range of island sizes and configurations which should predictably influence colonization, diversification and extinction. To explore the influence of these factors on archipelagic diversity, we relate the numbers of native and endemic species of vascular plants, birds, land snails and spiders – taxa having different dispersal capabilities and population densities – to the number and sizes of islands in the major oceanic archipelagos of the globe. Location Fourteen major oceanic archipelagos of the globe. Methods Species richness was collated for native and endemic species in each archipelago. We used linear mixed effect models to quantify the influence on diversity of total area, number of islands, isolation and latitude. We then applied process-based modelling in a Bayesian framework to evaluate how speciation, colonization and extinction are influenced by characteristics of archipelagos associated with species richness, i.e. area, isolation and number of islands. Results We found parallel scaling of species richness among taxa with respect to total area and number of islands across groups. The process-based model supported effects of isolation on colonization and of area and number of islands on extinction rates, with the scaling exponents mostly similar across taxa. Data are consistent with a range of scaling exponents for speciation rate, implying that those relationships are difficult to infer from the data used. Conclusions We demonstrate an unexpected parallel scaling of species richness of four taxa with area and number of islands for the major oceanic archipelagos of the globe. We infer that this scaling arises through similar effects of the physical characteristics of archipelagos on extinction, colonization and speciation rates across these disparate taxa, indicating that similar mechanisms have created variation in diversity.