Miracle-dz/UniFAR-FTUs huggingface dataset:
The late blight pathogen, Phytophthora infestans

The oomycete, Phytophthora infestans, is one of the most important plant pathogens worldwide. This thesis focuses on the late blight pathogen and its host, potato (Solanum tuberosum), and the interaction between these two organisms. Resistance to P. infestans was evaluated histologically, using leaves of potato cultivars with varying levels of general resistance. Preinfectional events could be ruled out as discriminating factors determining the level of resistance in the cultivars studied. After penetration of the pathogen into the leaf tissue there were significant differences between cultivars in hyphal growth and branching. The biochemical response of the tubers to pathogens, more specifically the accumulation of sesquiterpenoid metabolites and their biological effect on P. infestans was examined. Two unique sesquiterpenoid metabolites were isolated from tubers. The influence on mycelial growth of P. infestans of these compounds and of five naturally occurring plant sesquiterpenoids was tested. The two metabolites, isolated from tubers, induced a slight growth stimulation. All other compounds tested, suppressed the growth of the pathogen. The population structure of P. infestans in one single field in southwest Sweden was analysed with the aim to study the origin of the primary infections. Mitochondrial DNA, mating type and SSR-genotype were used as markers. Some foci were monomorphic for all markers, while other foci displayed a large proportion of unique genotypes. This was taken as evidence that inoculum had come both from tubers and oospores within this field. The dynamics of an epidemic and sexual reproduction of P. infestans was investigated in an experimental field inoculated with six different isolates of the pathogen. Three weeks after inoculation sampling was done. The following year, P. infestans isolates were baited from soil samples taken from the field. Parentage analysis, based on SSR markers, showed that recombinant genotypes from the inoculum isolates were present in the soil samples. These findings demonstrate that oospores produced during a summer epidemic in Sweden can overwinter and cause infection the next year.
The occurrence of herbicide cross-resistance in a population of annual ryegrass, Lolium rigidum, resistant to diclofop-methyl

A population of L. rigidum, which is known to have developed resistance to one of the diphenyl-ethertype of herbicides, diclofop-methyl, was tested for cross-resistance to three other herbicides of the same type, namely fluazifop-butyl, oxyfluorfen and the experimental herbicide CGA 82725. The population was also tested for cross-resistance to two sulfonylurea-type herbicides - chlorsulfuron and the experimental herbicide DPX-T6376. A population susceptible to diclofop-methyl was used as the controls in the tests. The two populations were treated with various rates of the herbicides during germination and at the two-leaf stage. The results show that the diclofop-methyl-resistant biotype was cross-resistant to fluazifop-butyl, CGA 82725, chlorsulfuron and DPX-T6376 but not to oxyfluorfen.
Iron Chlorotic Melon Germplasm C940-fe

The Fe chlorotic melon C940-fe germplasm (Cucumis melo L.) mutant was approved for release in 1991 by the Agricultural Research Service, U.S. Dept. of Agriculture. This mutant is controlled by a single recessive gene with the symbol fe (Pitrat, 1990), and it is independent of the virescent (v) gene (Nugent and Bhella, 1988). The mutant is being used for genetic, Fe metabolism, and nutrient uptake studies and also has potential for use in linkage and other genetic research (Hoffman and Nugent, 1973; Jolley et al., 1991; Nugent, 1987).
The protein pattern of spores of arbuscular mycorrhizal fungi: comparison of species, isolates and physiological stages

Spore proteins of different species and isolates of arbuscular mycorrhizal (AM) fungi were compared by PAGE. Reproducibility of protein patterns was assessed by using cultures of the same species either grown on different host plants, or produced during successive propagation cycles and stored up to 5 years. The results consistently showed that host species, different generations and storage, did not affect protein profiles, thus validating the accuracy of the method. Comparison among different geographical isolates of the same species revealed consistent protein patterns. The stability and diversity of spore protein profiles suggested that PAGE could be used to discriminate and identify AM fungal species and isolates. By contrast, the physiological state of spores affected the quality and quantity of bands, with germinating spores showing marked profile changes, as compared to quiescent spores, both in denaturating and native analytical conditions. The disappearance of some polypeptides in germinated spores might be related to the occurrence of storage proteins in AM fungi.
Factors influencing adult male Grapholita molesta dispersal in commercial Malus and Prunus host crops

The oriental fruit moth (OFM), Grapholita molesta (Busck) (Lepidoptera: Tortricidae), has been an economic pest of apples (Malus spp.) and peaches (Prunus spp.; both Rosaceae) in the eastern USA since the 1930s. Successful management of G. molesta with insecticides requires careful timing of these products based on sex‐pheromone trap captures of male moths. In Pennsylvania, apple and peach orchards are often planted adjacently. Factors such as trap distance from release points, host crop, and wind were considered in relation to male moth movement within and between hosts. Our practical objective was to understand male G. molesta dispersal within and between these two hosts to achieve better management. Recapture of moths decreased over distance; the majority of moths were recaptured 50–100 m from the release point regardless of crop type. Male G. molesta released into commercial apple and peach orchards were most likely to remain in the crop of release and to not exhibit host shifts over the season, even after peach fruit were harvested. Our analyses of wind direction data with respect to recapture showed that the likelihood of recapture was similar regardless of the orientation of the traps relative to the mean wind direction at peak flight times. The apple and peach host crops appeared to affect male G. molesta dispersal to the extent that wind in orchards affects their perception of pheromone. Crop effects were most likely due to the traps closest to the release points being in the same crop as the release points.
Antigen receptors on major histocompatibility complex-restricted T lymphocytes. I. Preparation and characterization of syngeneic antisera against trinitrophenyl-activated T cell blasts and demonstration of their specificity for idiotypes on cytotoxic T lymphocytes

This paper describes the specificity of AKR anti-(a) [AKR anti- trinitrophenylated AKR (AKR-TNP)] [AKRa (AKRaAKR TNP)] antisera raised in syngeneic AKR mice against AKRaAKR-TNP cell populations enriched for H-2-restricted aTNP cytotoxic lymphocytes (CTL) by blast-cell isolation. The activity of the antisera resided in the Ig fraction. All antisera were shown to reproducibly react with AKRaAKR-TNP-CTL- containing cell populations in indirect immunofluorescence and all removed the major fraction of CTL in complement-dependent lysis causing a considerable depression of cell-mediated lympholysis. The antisera were nonreactive with alloreactive AKRaC57BL/6 CTL and other H-2- restricted AKR CTL against fluorescein-isothiocyanate-conjugated AKR- target cells. It could be excluded that the antisera contained contaminating antibodies against TNP, TNP-neoantigenic determinants (NAD), or processed CTL-receptor-bound TNP-NAD, thus demonstrating specificity for determinants on T cell receptors of AKRaAKR-TNP CTL. These receptors were produced by the CTL themselves. These observations are interpreted to suggest that AKRa (AKRaAKR-TNP) antisera contain anti-idiotypic antibodies directed against specificity-associated determinants (idiotypes) on T cell receptors of H-2-restricted AKRaAKR- TNP CTL. The antisera provide a new tool to study the genetic control of idiotype expression on H-2-restricted CTL, the biochemistry of T cell receptors, and the regulation of the generation of H-2 restricted CTL on the idiotype level.
A cross‐seasonal perspective on local adaptation: metabolic plasticity mediates responses to winter in a thermal‐generalist moth

Summary The physiological and ecological impact of the thermal environment across life stages can result in trade-offs that determine fitness and population dynamics. Understanding mechanisms and consequences of local adaptation for any organism that overwinters requires taking a cross-seasonal perspective. We used a trait-based approach to distinguish variation among ecotypes in ecological and physiological responses to overwintering conditions. We used fall webworms (Hyphantria cunea; Lepidoptera: Arctiidae) from Ottawa, Ontario and Columbus Ohio, representing the centre and periphery of the native range. We hypothesized that populations would be locally adapted to their overwintering environments, with fitness maximized under natal overwintering conditions. We predicted that this local adaptation would result from modulation of rates of energy use, growth and development. Each ecotype had higher overwinter survival in their natal compared with non-natal winter environment, and this was associated with larger pupal mass, size and carbohydrate reserves at the end of winter. This suggests that the ecotypes are locally adapted to winter conditions. Larger adults laid more eggs, but there was no effect of ecotype or environment on fecundity. Pupae overwintering at warm, energetically demanding, southern temperatures suppressed metabolic rates in autumn, and developed more quickly in the spring, compensating for energetic demands of warmer winters. Northern ecotypes had lower thermal sensitivity of metabolism, leading to higher metabolic rates at cool temperatures that correlated with faster post-winter development. Local adaptation to winter conditions suggests performance of peripheral populations may not be enhanced by warming winters. Decoupling of winter and growing season temperatures may negatively impact ectotherms.
The influence of urbanization on the behaviour of an Australian lizard and the presence of an activity–exploratory behavioural syndrome

Urbanization is rapidly converting natural landscapes into habitats dominated by man-made structures. Urbanized areas possess a range of novel stressors such as increased human disturbance, different suites of predators, new food types and altered habitats and complexity. Species may need to adjust aspects of their behaviour to cope with these novel stressors and persist in areas following urbanization. Sydney, Australia's largest city, has undergone rapid population and geographic expansion over two centuries, but remains a mosaic of natural and heavily urbanized habitats. We adopted a behavioural syndrome approach to investigate whether urbanization has influenced the behaviour of the delicate skink Lampropholis delicata in the Sydney region. Lizards from one of the urban populations were more active, and more likely to forage for food, than individuals from the other three populations, but there was no difference in activity or foraging behaviour between urban and non-urban populations overall. Skinks from urban and non-urban habitats did not differ in their exploratory or basking behaviours. Activity, exploratory behaviour and foraging behaviour were all repeatable, and a behavioural syndrome linking high activity with increased exploration was evident. Our study documents the impact of urbanization on an understudied taxonomic group in the Southern Hemisphere, where urbanization has occurred relatively recently, and suggests that the influence on behaviour might be related to the degree of urbanization that has occurred.
Investigating Habitat use, Prey Consumption, and Dispersal Response as Potential Coexistence Mechanisms using Morphologically Similar Species of Predaceous Diving Beetles (Coleoptera: Dytiscidae)

ABSTRACT Differences in habitat use and dispersal responses among competing species are mechanisms that may influence patterns of coexistence. Predaceous diving beetles (Coleoptera: Dytiscidae) are a model group for testing these potential coexistence mechanisms because they are abundant, interact in finite habitats, and are mobile among habitats. We focused on two morphologically similar species, Laccophilus fasciatus rufus (Aubé) and Laccophilus proximus (Say), to determine if mechanisms exist that help to explain patterns of their coexistence. Behavioral observations and feeding trials in the laboratory, a field experiment, and a mesocosm experiment were used to determine if habitat use, prey consumption, or dispersal rates of these two species were inherently different or changed when in the presence of intra- or interspecific competitors. We found no difference between habitat use or prey consumption between species in constant depth aquaria, and no effect of intra- or interspecifics on their behaviors. In variable depth aquaria, L. proximus occupied significantly shallower habitat when compared with L. ƒ. rufus; in the former this difference only occurred between conspecific treatments. Field collections confirmed that L. proximus occupied shallower habitats than L. f. rufus. In field mesocosms, L. proximus displayed higher dispersal rates than L. ƒ. rufus. These species also do not appear food limited in the field, suggesting that adult competition for food is unlikely. L.f. rufus and L. proximus exhibit different habitat use and dispersal responses, but this does not seem to be in response to intra- or interspecific competitive interactions.
Differences in Siphonal Anatomy Between Dreissena polymorpha and D. bugensis (Mollusca: Dreissenidae) in Lake Ontario

Abstract The Great Lakes region has come to be occupied by at least two species of Dreissena, the zebra mussel, D. polymorpha and the quagga mussel, D. bugensis. The species are distinguished on the basis of shell morphology and electrophoretic patterns. Comparisons of the posterior mantle regions reveals differences between the two species in the extent of sensory papillae above the exhalant siphon and the point of union of the middle mantle fold.
Occurrence and abundance of fungus-dwelling beetles (Ciidae) in boreal forests and clearcuts: habitat associations at two spatial scales

Insect material (> 30,000 individuals) reared from the fruiting bodies of wood-decaying Trametes fungi was compared between old-growth boreal forests and adjacent clearcuts in Finland. Sulcacis affinis and Cis hispidus occurred more frequently and were, on average, more abundant in the clearcuts. Interestingly, Octotemnus glabriculus and Cis boleti had a slightly higher frequency of occurrence in the forests, despite lower resource availability. The former also showed a higher average abundance. On average, the cluster size of Trametes fruiting bodies occurring on woody debris was higher in the clearcuts than in the forests and had a positive effect on species occurrence and abundance in these clusters. The independent effect of the macrohabitat (forest or clearcut) underscores the importance of the macrohabitat where specific resources occur, and this may override the positive effects of resource availability.
Mitochondrial tRNA gene translocations in highly eusocial bees

Mitochondrial gene rearrangement events, especially involving tRNA genes, have been described more frequently as more complete mitochondrial genome sequences are becoming available. In the present work, we analyzed mitochondrial tRNA gene rearrangements between two bee species belonging to the tribes Apini and Meliponini within the “corbiculate Apidae”. Eleven tRNA genes are in different genome positions or strands. The molecular events responsible for each translocation are explained. Considering the high number of rearrangements observed, the data presented here contradict the general rule of high gene order conservation among closely related organisms, and also represent a powerful molecular tool to help solve questions about phylogeny and evolution in bees.
Climate and CO2 controls on global vegetation distribution at the last glacial maximum: analysis based on palaeovegetation data, biome modelling and palaeoclimate simulations

The global vegetation response to climate and atmospheric CO2 changes between the last glacial maximum and recent times is examined using an equilibrium vegetation model (BIOME4), driven by output from 17 climate simulations from the Palaeoclimate Modelling Intercomparison Project. Features common to all of the simulations include expansion of treeless vegetation in high northern latitudes; southward displacement and fragmentation of boreal and temperate forests; and expansion of drought‐tolerant biomes in the tropics. These features are broadly consistent with pollen‐based reconstructions of vegetation distribution at the last glacial maximum. Glacial vegetation in high latitudes reflects cold and dry conditions due to the low CO2 concentration and the presence of large continental ice sheets. The extent of drought‐tolerant vegetation in tropical and subtropical latitudes reflects a generally drier low‐latitude climate. Comparisons of the observations with BIOME4 simulations, with and without consideration of the direct physiological effect of CO2 concentration on C3 photosynthesis, suggest an important additional role of low CO2 concentration in restricting the extent of forests, especially in the tropics. Global forest cover was overestimated by all models when climate change alone was used to drive BIOME4, and estimated more accurately when physiological effects of CO2 concentration were included. This result suggests that both CO2 effects and climate effects were important in determining glacial‐interglacial changes in vegetation. More realistic simulations of glacial vegetation and climate will need to take into account the feedback effects of these structural and physiological changes on the climate.
Global phylogeography of the avian malaria pathogenPlasmodium relictumbased on MSP1 allelic diversity

Knowing the genetic variation that occurs in pathogen populations and how it is distributed across geographical areas is essential to understand parasite epidemiology, local patterns of virulence, and evolution of host-resistance. In addition, it is important to identify populations of pathogens that are evolutionarily independent and thus free' to adapt to hosts and environments. Here, we investigated genetic variation in the globally distributed, highly invasive avian malaria parasite Plasmodium relictum, which has several distinctive mitochondrial haplotyps (cyt b lineages, SGS1, GRW11 and GRW4). The phylogeography of P. relictum was accessed using the highly variable nuclear gene merozoite surface protein 1 (MSP1), a gene linked to the invasion biology of the parasite. We show that the lineage GRW4 is evolutionarily independent of GRW11 and SGS1 whereas GRW11 and SGS1 share MSP1 alleles and thus suggesting the presence of two distinct species (GRW4 versus SGS1 and GRW11). Further, there were significant differences in the global distribution of MSP1 alleles with differences between GRW4 alleles in the New and the Old World. For SGS1, a lineage formerly believed to have both tropical and temperate transmission, there were clear differences in MSP1 alleles transmitted in tropical Africa compared to the temperate regions of Europe and Asia. Further, we highlight the occurrence of multiple MSP1 alleles in GRW4 isolates from the Hawaiian Islands, where the parasite has contributed to declines and extinctions of endemic forest birds since it was introduced. This study stresses the importance of multiple independent loci for understanding patterns of transmission and evolutionary independence across avian malaria parasites. (Less)
ETS sequences support the monophyly of the eucalypt genus Corymbia (Myrtaceae)

The generic classification of the eucalypts, especially recognition of the genus Corymbia, has been controversial. The phylogeny of Corymbia and related eucalypt groups was investigated using nuclear ETS sequences, and combined ETS and ITS sequences. Both the ETS and combined datasets support the monophyly of Corymbia. Three major eucalypt clades are confirmed: Corymbia + Angophora; Eucalyptus s.s. ; and the Eucalyptopsis group. Within Corymbia, relationships are broadly consistent with phylogenies based on morphological and anatomical characters; sections Ochraria, Blakearia, and Politaria are all supported as monophyletic; sect. Rufaria is monophyletic with the inclusion of the monotypic sect. Apteria. Within Eucalyptus s.s. , relationships are generally consistent with those shown by previous molecular studies. Within the Eucalyptopsis group, Allosyncarpia is sister to the clade Stockwellia + Eucalyptopsis. Relationships between the major eucalypt clades are equivocal, but combined analysis of ETS and ITS data shows Corymbia + Angophora as sister to Eucalyptus-the rainforest taxa of the Eucalyptopsis group being outside this clade. Patterns of relationship and distribution are consistent with differentiation of major lineages of Corymbia prior to the isolation of taxa (now relictual) in eastern and south-western Australia, arguably before the midMiocene.
Microplankton community structure and the impact of microzooplankton grazing during an Emiliania huxleyi bloom, off the Devon coast

Phytoplankton and microzooplankton community structure and the impact of microzooplankton grazing were investigated during a one-day study of an Emiliania huxleyi bloom off the coast of Devon during July 1999. Vertical profiles were undertaken at four stations, along a transect which crossed from a low reflectance to a high reflectance area as seen by satellite imagery. Microzooplankton dilution grazing experiments, coupled with pigment analysis to determine class specific grazing rates, were performed at two of these stations. Highest concentrations of chlorophyll-a (5·3 mg m−3) and accessory pigments were measured inside the area of high reflectance. Phytoplankton standing stocks ranged between 1588 and 5460 mg C m−2 and were also highest in the area of high reflectance. The phytoplankton community was dominated by coccolithophores and diatoms in low reflectance waters and by photosynthetic dinoflagellates in high reflectance areas. Microzooplankton standing stocks ranged between 905 and 2498 mg C m−2. Protozoa dominated the microzooplankton community. The protozoan community comprised a relatively even mixture of heterotrophic dinoflagellates, non-choreotrich and choreotrich ciliates in low reflectance waters. However, non-choreotrich ciliates dominated the communities inside the high reflectance area. Of the heterotrophic ciliates, a predatory ciliate Askenasia sp. dominated both non-choreotrich abundance and biomass. Results from grazing experiments showed that 60–64% of the chlorophyll-a biomass was consumed daily by the microzooplankton. Highest grazing mortality was associated with peridinin (dinoflagellates) and alloxanthin (cryptophytes). Lower grazing rates were found on fucoxanthin (diatoms and prymnesiophytes). Our results indicate that grazing on E. huxleyi in the area of remotely sensed high reflectance was low and highest grazing was on photosynthetic dinoflagellates and cryptophytes.