Miracle-dz/UniFAR-FTUs huggingface dataset:
NH4 + assimilation in the ectomycorrhizal basidiomycete Laccaria bicolor (Maire) Orton, a 15 N-NMR study.

Nuclear magnetic resonance spectroscopy was used to monitor 15 NH4 + assimilation and amino acid biosynthesis in the ectomycorrhizal basidiomycete Laccaria bicolor (Maire) Orton. (strain S238). In mycelium growing rapidly on 15 NH4 + , [amido-15 N]glutamine was the major 15 N-labelled species. When 15 N-labelled mycelium was transferred into medium containing 14 NH4 + , the resonance for [amino-15 N]glutamine decreased with a half-life of about 3.0 h, whereas the resonance for [amino-15 N]glutamine remained unchanged. Such behaviour is consistent with glutamine synthetase (GS) being the major route of 15 NH4 + assimilation. However, the higher accumulation of [15 N]alanine observed in the presence of the GS inhibitor, methionine sulfoximine, indicated that a part of the glutamate pool was formed by the glutamate dehydrogenase (GDH) pathway. When the mycelium was in stationary phase (i.e. low extracellular NH4 + ), the intramolecular 15 N labelling of glutamine suggested that the GDH and GS pathways were simultaneously assimilating NH4 + . The N supply and the growth stage, therefore, influence the expression of the activities of GDH and GS. The current isotopic data identify other fates of absorbed 15 N: glutamate decarboxylation gives rise to γ-aminobutyrate; transamination between glutamate and pyruvate yields alanine; and arginine accumulates. It is concluded that GS is the main pathway of primary assimilation of NH4 + in L. bicolor, but GDH may also contribute significantly to this process.
THE EFFECT OF FEEDING DIETS CONTAINING WHITE FISHMEAL ON ACCEPTABILITY AND FLAVOR INTENSITY OF ROASTED BROILER CHICKENS

Diets containing 0, 3, 9, 14 and 19% white fishmeal and a diet containing 15% high-fat fishmeal were fed to the females of a commercial strain of broilers. Activated charcoal at the 0.5% level was added to the six finisher diets for one-half of the birds. The effect of starving birds for 24 and 72 hours after being fed the 19% fishmeal finisher diet was also evaluated; the starved birds were fed a ration containing 0% fishmeal from 63 to 72 days of age. The broilers were roasted without seasonings. A piece of dark meat and white meat with its skin from each of the diets was presented to 10 judges. This was repeated 10 times. Each judge was asked to state if the sample was acceptable or not, and to rate its flavor from no off-flavor to extreme fishy flavor. Tests were also run on cooking losses, color, moisture, texture and ether extract. Significant differences were found between the control (0% fishmeal) and the 15% high-fat and 19% fishmeal broilers for acceptability and flavor intensity. There were no .
The evolution of growth‐forms in the Macaronesian genus Aeonium (Crassulaceae) inferred from chloroplast DNA RFLPs and morphology

Phylogenetic relationships among species of Aeonium were studied using morphological characters and chloroplast DNA RFLPs. Cladistic analysis of weighted morphological data indicates that the small, herbaceous and least woody species are basal in the genus. Chloroplast DNA data gave similar results, supporting the separation of the herbaceous or small, woody species from the large, hapaxanth rosettes, rosette trees, and branched subshrubs with yellow, white or red flowers as well as the only (herbaceous) species with axillary inflorescences. The relationships among the species descending from a polytomy that comprises all species of the genus as well as a polytomy which comprises 18 of the 26 species studied, are only very incompletely resolved, except for two monophyletic clades that contain the branched subshrubs with yellow flowers (A. sect. Aeonium) and the branched subshrubs and rosette trees with white or red flowers (A. sect. Leuconium), respectively. Cladistic analysis of the combined morphological and chloroplast DNA data improved resolution considerably. Four monophyletic clades are distinguished, each of which, except for three species, comprises only one of the five main growth‐form types. Although Aeonium is generally regarded as an outstanding example of adaptive radiation, this mode of speciation seems to have been of minor significance in the evolution of the genus, because each growth‐form apparently evolved only once. Instead, island speciation in the absence of major ecological shifts, is probably more important in the evolution of the genus.
Effects of the Parasite Eimeria Arizonensis on Survival of Deer Mice (Peromyscus Maniculatus)

Few experimental studies have documented the negative effect of parasites on fitness of hosts under natural or seminatural conditions. We studied the effect of Eimeria arizonensis (Protozoa) on recruitment, winter survival, and change in body mass in deer mice (Peromyscus maniculatus). In field observations, the presence of E. arizonensis was negatively related to recruitment in females and to over—winter survival in males. Experimental manipulation of E. arizonensis in large field enclosures also showed that infection negatively affected over—winter survival of males. There was no relationship between the body mass of deer mice and the presence of either natural or experimental infection. Thus, the mechanism through which E. arizonensis affects survival remains unclear. See full-text article at JSTOR
Suspects and evidence: a review of the causes of extirpation and decline in freshwater mussels

Conservation of biodiversity requires reliable evidence of the causes of extirpation. Using freshwater mussels as an example, we performed the first-ever systematic assessment of the evidence for endangerment of any group of organisms. We surveyed articles publishing conclusions about the cause of local extirpation by assessing the quality of evidence on an objective scale. We found that only 48% of studies presented plausible links between extirpation and causes. Analyses lacked resolution since more than 75% of all studies considered (n = 124) suggested multiple causes of extirpation. Studies performed over large areas and those presenting less evidence postulated the most causes. Despite the frequently weak evidence, there was substantial agreement on the identity of causes; the most frequent was habitat destruction or alteration but many others were postulated. Although mussel extirpation is undoubtedly real, the evidence could be stronger. In these animals and others, evidence of the causes of extirpation has often been circumstantial. We present a systematic approach ecologists can use to strengthen the evidence concerning the causes of extirpation. We also reflect on the link between the strength of evidence and research funding priorities.
Determinação de Níveis de Metionina+Cistina para Poedeiras Semi-pesadas Alimentadas com Rações contendo Levedura Seca (Saccharomyces cerevisiae)

One experiment was carried out using 120 laying Isa Brown chickens fed diets containing sugar-cane yeast, to determinate the methionine+cystine (met+cys) requirements. The birds were 51 weeks old at the beginning of the experiment, with the duration of 84 days, with three periods of 28 days each. A completely randomized block design with five treatments and four replications was used. The treatments consisted of a basal diet supplemented with five levels of DL-methionine in order to obtain diets with 0.45, 0.50, 0.55, 0.60, and 0.65% of met+cys. The basal diet with 13%CP and 2840 kcal EM/kg was composed by corn, soy bean meal and sugar-cane yeast. Referring variables were analyzed to the productive performance (production of eggs, weight gain, feed consumption and conversion) and quality of the eggs (weigh, mass and content of eggs and Haugh Units). A quadratic effect of the met+cys levels was observed on the appraised characteristics, except for the weight gain that was not influenced by the treatments. Working with regression models, it was possible the determination of the best met+cys levels. For greater egg production and ration consumption, the requirements were . 565 and . 569% of met+cys, respectively. For egg weight and egg mass the use of . 582% and . 569% of met+cys, allowed to obtain the better results, respectively.
A two–stage model for Cepaea polymorphism

The history of the study of snails in the genus Cepaea is briefly outlined. Cepaea nemoralis and C. hortensis are polymorphic for genetically controlled shell colour and banding, which has been the main interest of the work covered. Random drift, selective predation and climatic selection, both at a macro- and micro-scale, all affect gene frequency. The usual approach to understanding maintenance of the polymorphism, has been to look for centripetal effects on frequency. Possible processes include balance of mutation pressure and drift, heterozygote advantage, relational balance heterosis, frequency-dependent predation, multi-niche selective balance, or some combination of these. Mutational balance is overlaid by more substantial forces. There is some evidence for heterosis. Predation by birds may protect the polymorphism, and act apostatically to favour distinct morphs. Although not substantiated for Cepaea, many studies show that predators behave in the appropriate manner, while shell colour polymorphisms in molluscs occur most commonly in species exposed to visually searching predators. It is not known whether different thermal properties of the shells help to generate equilibria. Migration between colonies is probably greater than originally thought. The present geographical range has been occupied for less than 5000 generations. Climatic and human modification alter snail habitats relatively rapidly, which in turn changes selection pressures. A simple simulation shows that migration coupled with selection which fluctuates but is not centripetal, may retain polymorphism for sufficiently long to account for the patterns we see today. There may therefore be a two-stage basis to the polymorphism, comprising long-term but weak balancing forces coupled with fluctuating selection which does not necessarily balance but results in very slow elimination. Persistence of genetic variants in this way may provide the conditions for evolution of a balanced genome.
The relationship of grain filling with abscisic acid and ethylene under non-flooded mulching cultivation

SUMMARY Grain filling is an intensive transportation process regulated by plant hormones. The present study investigated whether and how the interaction between abscisic acid (ABA) and ethylene is involved in mediating the grain filling of rice (Oryza sativa L.) under non-flooded mulching cultivation. A field experiment repeated over 2 years was conducted with two high-yielding rice cultivars, Zhendao 88 (a japonica cultivar) and Shanyou 63 (an indica hybrid cultivar), and four cultivation treatments were imposed from transplanting to maturity: traditional flooding as control (TF), non-flooded plastic film mulching (PM), non-flooded wheat straw mulching (SM) or non-flooded no mulching (NM). Compared with that under TF, grain yield was reduced by 21·0–23·1% under PM (P<0·05), 1·4–1·8% under SM (P>0·05) and 50·9–55·4% under NM (P<0·05). Both PM and NM significantly (P<0·05) reduced the proportion of filled grains and grain weight and were associated with decreased grain filling rates. In SM there was a significant increase in the grain filling rate. The concentration of ABA in the grains was very low at the early grain filling stage, reaching a maximum when the grain filling rate was the highest, and showed no significant differences (P>0·05) between TF, PM and SM. However, it was significantly higher in NM. In contrast to ABA, the ethylene evolution rate and 1-aminocyclopropane-1-carboxylic acid (ACC) concentration in the grains were very high at the start of grain filling and sharply decreased during the active grain filling period. Both PM and NM increased the ethylene evolution rate and ACC concentration, whereas these were reduced in SM. The ratio of ABA to ACC was increased under SM but decreased under PM and NM, indicating that ethylene was more enhanced than ABA when plants were grown under NM and PM. The concentration of ABA correlated with the grain filling rate as a hyperbolic curve, whereas the ethylene evolution rate correlated with the grain filling rate as an exponential decay equation. The ratio of ABA to ACC significantly correlated with the grain filling rate with a linear relationship. Application of amino-ethoxyvinylglycine (inhibitor of ethylene synthesis by inhibiting ACC synthase) or ABA to panicles under TF and PM at the early grain filling stage significantly increased activities of the key enzymes involved in sucrose to starch conversion in the grains, sucrose synthase, ADP glucose pyrophosphorylase and soluble starch synthase, grain filling rate and grain weight. Application of ethephon (ethylene-releasing agent) or fluridone (inhibitor of ABA synthesis) had the opposite effect. The results suggest that antagonistic interactions between ABA and ethylene may be involved in mediating the effect of non-flooded mulching cultivation on grain filling, and a high ratio of ABA to ethylene enhances grain filling rate.
Extensive Predator Space Use Can Limit the Efficacy of a Control Program

Abstract Reduced to small isolated groups by anthropogenic habitat losses or habitat modifications, populations of many endangered species are sensitive to additive sources of mortality, such as predation. Predator control is often one of the first measures considered when predators threaten survival of a population. Unfortunately, predator ecology is often overlooked because relevant data are difficult to obtain. For example, the endangered Gaspésie caribou (Rangifer tarandus caribou) has benefited from 2 periods of predator control that targeted black bears (Ursus americanus) and coyotes (Canis latrans) in an attempt to reduce predation on caribou calves. Despite a high trapping effort, the number of predators removed has remained stable over time. To assess impact of predator movements on efficacy of a control program, we studied space use of 24 black bears and 16 coyotes over 3 years in and around the Gaspésie Conservation Park, Quebec, Canada, using Global Positioning System radiocollars. Annual home ranges of black bears averaged 260 km2 and 10 individuals frequented area used by caribou. Annual home ranges of resident coyotes averaged 121 km2, whereas dispersing coyotes covered >2,600 km2. Coyotes were generally located at lower altitudes than caribou. However, because coyotes undertook long-distance excursions, they overlapped areas used by caribou. Simulations based on observed patterns showed that 314 bears and 102 coyotes potentially shared part of their home range with areas used by female caribou during the calving period. Despite low densities of both predator species, extensive movement and use of nonexclusive territories seem to allow predators to rapidly occupy removal areas, demonstrating the need for recurrent predator removals. Our results underscore the necessity of considering complementary and alternative solutions to predator control to assure long-term protection of endangered species.
Molecular Genetic Analysis of an Endotoxin Nonresponder Mutant Cell Line

Somatic cell mutagenesis is a powerful tool for characterizing receptor systems. We reported previously two complementation groups of mutant cell lines derived from CD14-transfected Chinese hamster ovary–K1 fibroblasts defective in responses to bacterial endotoxin. Both classes of mutants expressed a normal gene product for Toll-like receptor (TLR)4, and fully responded to stimulation by tumor necrosis factor (TNF)-α or interleukin (IL)-1β. We identified the lesion in one of the complementation groups in the gene for MD-2, a putative TLR4 coreceptor. The nonresponder phenotype of this mutant was reversed by transfection with MD-2. Cloning of MD-2 from the nonresponder cell line revealed a point mutation in a highly conserved region resulting in a C95Y amino acid exchange. Both forms of MD-2 colocalized with TLR4 on the cell surface after transfection, but only the wild-type cDNA reverted the lipopolysaccharide (LPS) nonresponder phenotype. Furthermore, soluble MD-2, but not soluble MD-2C95Y, functioned to enable LPS responses in cells that expressed TLR4. Thus, MD-2 is a required component of the LPS signaling complex and can function as a soluble receptor for cells that do not otherwise express it. We hypothesize that MD-2 conformationally affects the extracellular domain of TLR4, perhaps resulting in a change in affinity for LPS or functioning as a portion of the true ligand for TLR4.
An Examination of Methods for Determining Organic Carbon and Nitrogen in Soils. (With One Text-figure.)

1. The details of the Dennstedt dry-combustion method for determining carbon in soils were described, and some simplifications suggested. 2. The Bangor modified Kjeldahl method for carbon and nitrogen in soils requires carefully standardised heating. Errors may arise from contamination of sandy soils by material abraded during grinding in iron or porcelain mills. 3. For many heavy soils the addition of water before the Kjeldahl digestion is convenient but not essential. For heavy alkaline soils with little organic matter it is advisable to grind the soil very finely and to add water.
Death of the cortex of roots in relation to invasion by fungal parasites

In glasshouse and laboratory conditions, death of root cortices of cereal and tomato plants was followed by nuclear and cytoplasmic staining methods. Various treatments were applied to whole plants or sterile root pieces on agar, to study factors that influence root tissue senescence and its relationship to invasion by the parasitic fungi Microdochium bolleyi, Pyrenochaeta lycopersici and Gaeumannoniyces graminis var. tritici (Ggt). Other experiments involved growth and sporulation of M. bolleyi in culture, and the ability of this fungus to spread on roots by spores produced on seeds or roots, to facilitate development of M. bolleyi as a seedapplied biocontrol agent of plant pathogens. Nuclear staining with acridine orange was satisfactory for assessing root cell viability in cereals but not in tomato, for which neutral red/plasmolysis was used; no other cytochemical method was suitable for routine work with either plant. Sterile detached root pieces of wheat and tomato senesced rapidly on media without sucrose, but tomato root cells remained alive on media of low sucrose concentration (0.1%), whereas wheat root. cortical death (RCD) was delayed but not inhibited by even high sucrose levels. RCD was also delayed by removal of the shoot, root tip or seed from sterile wheat seedlings; supply of sucrose or minerals to only part of a root piece did not affect the pattern of RCD. Indolylacetic acid, Ag or CO 2 delayed RCD in wheat root pieces on agar, but other growth regulators accelerated RCD. The results suggest that RCD in cereals is programmed and internally regulated, being only slightly modified by external factors. M. bolleyi invaded senescing cereal root cortices mainly intercellularly. It accelerated RCD of detached roots but had little effect on attached roots; it invaded tomato roots only poorly.
Intraguild Predation and Competition Between Larval Dragonflies: Direct and Indirect Effects on Shared Prey

We conducted manipulative field experiments in artificial ponds to quantify the predatory impact of larvae of a migratory dragonfly (Tramea lacerata) on a common resident dragonfly species (Erythemis simplicicollis), and on damselflies as shared prey of the two dragonflies. We found that the combined predatory effects of the two dragonflies on damselflies were not additive. To determine the underlying cause of non-additive pre- dation rates in the field, we conducted a second experiment in laboratory aquaria to isolate the impact of each predator on the consumption rates of the other. Dragonfly consumption rates of damselflies in single-predator treatments were compared to those in the presence of heterospecifics or conspecifics with their menta mouthpartss) surgically modified so that they could not capture prey. In the laboratory experiment, de-mented Tramea reduced the consumption rates of Erythemis to less than half of that observed when Erythemis foraged alone. Erythemis numbers were also reduced by Tramea predation. Erythemis had neither effect on Tramea. Both of the negative effects of Tramea on Erythemis will have indirect positive effects on damselflies. The "behavioral" component (reduced Erythemis foraging rate) should be more important than the "trophic link" (reduced Erythemis numbers) indirect effect. To- gether these indirect positive effects will allay, but not completely compensate for, the direct negative effects of Tramea predation on damselflies. These results illustrate how an asymmetric potential for intraguild predation can lead to asymmetries in interference competition and to non-additive effects on prey mortality. The addition or removal of predators that interact in this manner to or from communities should have only a small net effect on prey because of compensating direct and indirect effects. This may explain why predator manipulations have often had unpredictable or undetectable effects on freshwater benthic communities.
Seed mass, seed production, germination and seedling traits in two phenological types of Bidens pilosa (Asteraceae)

Bidens pilosa L. is a summer annual that shows a particular phenological pattern in the C´ ordoba mountains, Argentina. Some individuals start flowering 1 month after germination (early type), but most of the population starts flowering 4 months after germination (normal type). The aims of this study were to (1) analyse whether differences in flowering phenology affect seed mass and seed production, and (2) assess whether possible differences in seed traits of the two parental phenological types would affect germinability, germination rate, seedling growth and flowering phenology of offspring under laboratory conditions. The study showed that the numbers of seeds per capitulum and per plant were greater in the normal type than in the early type plants. This can be related to plant height, since in the field, normal-type plants are larger than early type plants. However, early type plants produced heavier seeds than normal-type plants. Germination rate was faster in the early type seeds, but total germination was higher in the normal ones. Seedling growth, in terms of height and the date of first flowering, did not differ between the phenological types of parental seed sources. Our results showed that differences in flowering phenology were associated with seed mass and seed production differences. Seed mass appears to be related to germination characteristics but not to seedling growth nor to flowering phenology of offspring.
HOLARCTIC PHYLOGEOGRAPHY AND SPECIES LIMITS OF THREE-TOED WOODPECKERS

Abstract We compared mitochondrial DNA sequences of Three-toed Woodpeckers (Picoides tridactylus) within and between Eurasia and North America. Samples from the two continents are each reciprocally monophyletic, and differ by approximately 4% sequence divergence, suggesting that a separate species exists on each continent. We recommend formal taxonomic action. Within continents, no phylogeographic structuring was found, suggesting that both species have recently expanded their ranges following the end of the last ice age. Filogeografía Holártica y Límites de la Especie Picoides tridactylus Resumen. Comparamos secuencias de ADN mitocondrial en Picoides tridactylus, dentro y entre Eurasia y América del Norte. Las muestras de cada uno de los dos continentes son recíprocamente monofiléticas y difieren aproximadamente en un 4% de divergencia secuencial, sugiriendo que existe una especie distinta en cada continente. Recomendamos acción taxonómica formal. No encontramos estructura filogeográfica dentro de los continentes, sugiriendo que ambas especies han expandido recientemente sus rangos luego del final de la última era glacial.