bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biochemical characterization of Drosophilaγ‐glutamyl carboxylase and its role in fly development
Authors: Bandyopadhyay P. K. , Clark K. , Stevenson B. J. , Rivier J. E. , Olivera B. M. , Golic K. G. , Rong Y. S. 
Published: March 2006

AbstractTo investigate structure‐function relationships in γ‐glutamyl carboxylases, the enzyme from Drosophila melanogaster was characterized. Four cysteine residues were shown to be important determinants for enzymatic activity. Native Drosophila substrates have not yet been identified, but propeptides of human prothrombin and factor IX are recognized by the Drosophila enzyme. The presence of the propeptide region increased apparent affinity by ∼200‐fold, and mutation of a hydrophobic residue of factor IX propeptide (F‐16A) decreased carboxylation by 90%, as in the human enzyme. Substrate recognition appears to be highly conserved between the human and Drosophilaγ‐glutamyl carboxylases. Inactivation of Drosophilaγ‐glutamyl carboxylase by non‐sense mutations or insertional mutagenesis by P‐element insertion have no apparent effects on growth and fertility under laboratory conditions.
Frequencies of the pyrethroid resistance alleles of Vssc1 and CYP6D1 in house flies from the eastern United States
Authors: Rinkevich F. D. , Zhang L. , Hamm R. L. , Brady S. G. , Lazzaro B. P. , Scott J. G. 
Published: March 2006

AbstractHouse flies were collected from four dairies in Maine, New York, North Carolina, and Florida, where high levels of resistance to permethrin have been documented. Regions of two genes, CYP6D1 and Vssc1, having alleles that confer resistance to permethrin (and other pyrethroids) were analysed from individuals at each collection site. The combinations of resistance alleles for Vssc1 and CYP6D1 were highly variable between each state. The resistance allele CYP6D1v1 was found at a high frequency (0.63–0.91) at all sites. Individuals homozygous susceptible for CYP6D1 were very rare and detected only at the dairy in Maine. In addition to the typical Vssc1 mutation responsible for resistance, kdr (L1014F), we also identified individuals with a L1014H mutation. Although house flies homozygous for the L1014H mutation had a lower level of resistance to permethrin, compared to L1014F, the H1014 resistance allele was frequently detected. No individuals with the super‐kdr allele (M918T + L1014F) were detected from the field collections. The intron 3 bp downstream of the kdr mutation was found to be extremely variable, providing an opportunity to reconstruct a phylogeny of Vssc1 alleles. Based on this analysis it appears the kdr‐his mutation had multiple evolutionary origins, but that the kdr mutation may have had a single origin. The impacts of these findings on resistance management are discussed.
Positional cloning of a cyromazine resistance gene in Drosophila melanogaster
Authors: Chen Z. , Robin C. , Damiano J. , Lydall J. , Lumb C. , Smith K. , Blasetti A. , Daborn P. J. , Heckel D. , McKenzie J. A. , Batterham P. 
Published: March 2006

AbstractCyromazine is an effective insecticide used to control dipteran insects. Its precise mode of action is yet to be determined, although it has been suggested that it interferes with the hormone system, sclerotization of the cuticle, or nucleic acid metabolism. To understand the way in which cyromazine acts, we have positionally cloned a cyromazine resistance gene fromDrosophila melanogaster. Six cyromazine resistance alleles had previously been generated by ethyl methanasulphonate treatment. Two of these failed to complement each other and here we identify them as having independent non‐sense mutations inCG32743, which is an ortholog ofSmg1of worms and mammals and encodes a phosphatidylinositol kinase‐like kinase (PIKK). RNAi experiments confirm that cyromazine resistance can be achieved by knocking downCG32743. These are the first cyromazine resistant mutations identified at the nucleotide level. In mammalsSmg1phosphorylates P53 in response to DNA damage. This finding supports the hypothesis that cyromazine interferes with nucleic acid metabolism.
Remarkable substrate‐specificity of CYP6AB3 in Depressaria pastinacella, a highly specialized caterpillar
Authors: Mao W. , Rupasinghe S. , Zangerl A. R. , Schuler M. A. , Berenbaum M. R. 
Published: March 2006

AbstractThe parsnip webworm, Depressaria pastinacella, a specialist on two genera in Apiaceae, feeds exclusively on the furanocoumarin‐containing reproductive structures of its host plants. This caterpillar relies principally on cytochrome P450‐mediated detoxification for coping with the high concentrations of furanocoumarins in its diet. A cDNA encoding the furanocoumarin‐inducible P450 CYP6AB3 from this species was coexpressed with house‐fly NADPH P450 reductase in baculovirus‐infected Sf9 cells and tested for binding and metabolism of the six furanocoumarins typically encountered in host plant tissues. Only imperatorin and bergapten bind in close proximity to the catalytic haem and only imperatorin is metabolized (Vmax and Km of 2.412 pmol/min per pmol P450 and 94.28 µm, respectively). Purification of the imperatorin metabolite by normal phase HPLC and characterization of its structure by MS–MS analysis indicate that CYP6AB3 initially epoxidizes the carbon–carbon pi‐bond on the isoprenyl side chain on imperatorin. An improved molecular model for the CYP6AB3 protein based on this biochemical characterization and the recently defined mammalian CYP3A4 crystal structure provides insight into the remarkable substrate specificity of this protein.
Isolation, endocrine regulation and mRNA distribution of the 3‐hydroxy‐3‐methylglutaryl coenzyme A synthase (HMG‐S) gene from the pine engraver, Ips pini (Coleoptera: Scolytidae)
Authors: Bearfield J. C. , Keeling C. I. , Young S. , Blomquist G. J. , Tittiger C. 
Published: March 2006

AbstractWe isolated a full‐length cDNA encoding 3‐hydroxy‐3‐methylglutaryl coenzyme A synthase (HMG‐S) from the pine engraver beetle, Ips pini (Say), and examined its genomic structure. The intron‐less gene has a predicted 460 amino acid cytosolic protein product with 73% identity to HMG‐S from Dendroctonus jeffreyi, and high identity (58–64%) with other insect HMG‐Ss. Topically applied juvenile hormone (JH) III induced HMG‐S mRNA levels up to 6.5‐fold in both sexes, mostly in the anterior midgut, though there were differences between males and females in the timing, sensitivity to JH III dose and tissue distribution of HMG‐S mRNA. These data further validate the coordinate regulation of mevalonate pathway genes for de novo isoprenoid pheromone production in bark beetles.
Co‐immunoprecipitation of putative proteins that interact with mosquito proliferating cell nuclear antigen
Authors: Ma L. , Gerenday A. , Coley K. M. , Fallon A. M. 
Published: March 2006

AbstractWe have sequenced cDNAs encoding proliferating cell nuclear antigen (PCNA) from Aedes albopictus cells and from Aedes aegypti mosquitoes. The mosquito cDNAs contained an open reading frame encoding a 260 amino acid protein with a calculated mass of 29.0 kDa and a pI of 4.46. There was a single amino acid difference between PCNA proteins from Ae. albopictus and Ae. aegypti. In An. gambiae, the PCNA homolog contained 260 residues, and the pcna gene was interrupted by a single 67 nucleotide intron in the βC2 region of the protein. A phylogenetic comparison grouped known Dipteran PCNA sequences into two clusters, representing the Nematocera and the Cyclorrhapha. PCNA transcripts measured 1.1 kb, and were stable, as was PCNA protein. Mosquito PCNA was efficiently recognized by a commercially available mouse anti‐PCNA monoclonal antibody, which coprecipitated 29 kDa and 35 kDa proteins from mosquito cells representing different growth states. These results support the feasibility of recovering mosquito cell cycle inhibitory proteins by virtue of their interaction with PCNA.
Effects of juvenile hormone on gene expression in the pheromone‐producing midgut of the pine engraver beetle, Ips pini
Authors: Keeling C. I. , Bearfield J. C. , Young S. , Blomquist G. J. , Tittiger C. 
Published: March 2006

AbstractJuvenile hormone III (JH III) stimulates biosynthesis of the monoterpenoid aggregation pheromone component, ipsdienol, in the anterior midgut of the male pine engraver beetle, Ips pini (Say). To understand better the hormonal regulation of pheromone biosynthesis in this forest pest, and identify JH III‐responsive genes, microarrays were prepared and hybridized to cDNA from midguts of JH III‐treated beetles. Expression patterns were confirmed by quantitative real‐time RT–PCR. JH III co‐ordinately regulated mevalonate pathway genes and many other genes implicated in pheromone biosynthesis. Sex differences in basal levels of mevalonate pathway genes were consistent with their role in male‐specific pheromone biosynthesis. This is the first microarray‐based study of the developmental and hormonal regulation of insect pheromone biosynthesis.
The mitochondrial genome of the Korean hairstreak, Coreana raphaelis (Lepidoptera: Lycaenidae)
Authors: Kim I. , Lee E. M. , Seol K. Y. , Yun E. Y. , Lee Y. B. , Hwang J. S. , Jin B. R. 
Published: March 2006

AbstractWe determined the complete nucleotide sequences of the mitochondrial genome (mitogenome) of the Korean hairstreak, Coreana raphaelis (Lepidoptera: Lycaenidae). The entire mitochondrial DNA (mtDNA) molecule was 15 314 bp long. The C. raphaelis genes were in the same order and orientation as the completely sequenced mitogenomes of other lepidopteran species, except for the presence of an extra copy of tRNASer(AGN). High similarity in primary sequence and secondary structure between the two tandemly located copies of the tRNASer(AGN) suggest a recent duplication of an original single tRNASer(AGN). The DHU arm of the two copies of tRNASer(AGN) formed a simple loop as seen in many other metazoan mt tRNASer(AGN). The putative initiation codon for the C. raphaelis COI gene appears to be a tetranucleotide, TTAG, found commonly in the sequenced lepidopterans. ATPase8, ATPase6, ND4L and ND6 genes, which are next to another protein‐coding gene at their 3′ end all had the sequences potential to form a hairpin structure, suggesting the importance of such a structure for precise cleavage of the mature protein‐coding genes.
Caste‐specific cytochrome P450 in the damp‐wood termite Hodotermopsis sjostedti (Isoptera, Termopsidae)
Authors: Cornette R. , Koshikawa S. , Hojo M. , Matsumoto T. , Miura T. 
Published: March 2006

AbstractTermites are eusocial insects with a well‐defined caste system, which is an example of polyphenism. This polyphenism is based on hormonally controlled differential gene expression. In the damp‐wood termite Hodotermopsis sjostedti, we induced differentiation into the soldier caste by using juvenile hormone analogue treatment. We then investigated specific gene expression, which appeared during the hormonal response and triggered caste differentiation, using fluorescent differential display. A candidate cDNA sequence with similarity to cytochromes P450, CYP6AM1, was characterized and its transcript shown to be repressed between 1 and 3 days after hormone treatment. CYP6AM1 was specifically expressed in the fat body of pseudergates and soldiers. The putative function of this P450 is discussed with respect to the caste differentiation system.
Sex‐, stage‐ and tissue‐specific regulation by a mosquito hexamerin promoter
Authors: Jinwal U. K. , Zakharkin S. O. , Litvinova O. V. , Jain S. , Beneš Helen 
Published: March 2006

AbstractA portion of the 5′‐flanking region of the female‐specific hexamerin gene, Hex‐1.2, from the mosquito Ochlerotatus atropalpus was used to drive expression of the luciferase reporter gene in Drosophila melanogaster. The proximal 0.7 kb of 5′‐flanking DNA were sufficient to partially repress reporter gene activity in males and to drive tissue‐ and stage‐specific expression comparable with that of the endogenous O. atropalpus Hex‐1.2 gene. The Drosophila doublesex transcription factor (DSX), expressed in Escherichia coli, bound putative DSX sites of the Hex‐1.2 gene differentially in vitro. Blocking expression of the female isoform of the Doublesex transcription factor in transgenic female flies resulted in reduction of luciferase expression to levels comparable with those in males, suggesting that Doublesex could contribute to regulation of female‐specific expression of the O. atropalpus Hex‐1.2 gene.
Factors affecting wafer sheet quality
Authors: Dogan Ismail S. 
Published: March 2006

SummaryWafers are low‐moisture‐baked foods. They are formed from a batter and baked between hot plates. The quality of wafer sheets is mainly controlled by flour property, water level and temperature, mixing action, baking time and temperature. The quality is judged by attributes of the batter such as the density, viscosity, holding time and temperature, and by properties of the wafer such as weight, surface colour, fragility and moisture content. In this study, the batter‐specific gravity of 1.11–1.19 was recorded. Water and gluten content did not affect density. Water level, but not gluten content, however affected viscosity. Batter holding time drastically changed viscosity. The temperature of plates did significantly affect bake time. For wafer sheets with a high quality, 155–165% water level, 170 °C baking temperature and 2 min of bake time were found to be adequate. Wafer sheets baked at the lower temperatures stuck to the plates and broke up to several pieces. At a lower water level (<145%) and baking temperature of 150 °C, tough and flinty sheets were obtained, whereas at a water level higher than 160% and a higher temperature (190 °C), fragile sheets were obtained.
Contrasting cascades: insectivorous birds increase pine but not parasitic mistletoe growth
Authors: MOONEY KAILEN A. , LINHART YAN B. 
Published: March 2006

SummaryIntraguild predation occurs when top predators feed upon both intermediate predators and herbivores. Intraguild predators may thus have little net impact on herbivore abundance. Variation among communities in the strength of trophic cascades (the indirect effects of predators on plants) may be due to differing frequencies of intraguild predation. Less is known about the influence of variation within communities in predator–predator interactions upon trophic cascade strength.We compared the effects of a single predator community between two sympatric plants and two herbivore guilds. We excluded insectivorous birds with cages from ponderosa pinePinus ponderosatrees parasitized by dwarf mistletoeArceuthobium vaginatum. For 3 years we monitored caged and control trees for predatory arthropods that moved between the two plants, foliage‐feeding caterpillars and sap‐feeding hemipterans that were host‐specific, and plant damage and growth.Excluding birds increased the abundance of ant‐tended aphids on pine and resulted in an 11% reduction in pine woody growth. Mutualist ants protected pine‐feeding aphids from predatory arthropods, allowing aphid populations to burgeon in cages even though predatory arthropods also increased in cages. By protecting pine‐feeding aphids from predatory arthropods but not birds, mutualist ants created a three‐tiered linear food chain where bird effects cascaded to pine growth via aphids.In contrast to the results for tended aphids on pine, bird exclusion had no net effects on untended pine herbivores, the proportion of pine foliage damaged by pine‐feeding caterpillars, or the proportion of mistletoe plants damaged by mistletoe‐feeding caterpillars. These results suggest that arthropod predators, which were more abundant in cages as compared with control trees, compensated for bird predation of untended pine and mistletoe herbivores.These contrasting effects of bird exclusion support food web theory: where birds were connected to pine by a linear food chain, a trophic cascade occurred. Where birds fed as intraguild predators, the reticulate food webs linking birds to pine and mistletoe resulted in no net effects on herbivores or plant biomass. Our study shows that this variation in food web structure occurred between sympatric plants and within plants between differing herbivore guilds.
Ontogeny of diving behaviour in the Australian sea lion: trials of adolescence in a late bloomer
Authors: FOWLER SHANNON L. , COSTA DANIEL P. , ARNOULD JOHN P. Y. , GALES NICHOLAS J. , KUHN CAREY E. 
Published: March 2006

Summary

Foraging behaviours of the Australian sea lion (Neophoca cinerea) reflect an animal working hard to exploit benthic habitats. Lactating females demonstrate almost continuous diving, maximize bottom time, exhibit elevated field metabolism and frequently exceed their calculated aerobic dive limit. Given that larger animals have disproportionately greater diving capabilities, we wanted to examine how pups and juveniles forage successfully.
Time/depth recorders were deployed on pups, juveniles and adult females at Seal Bay Conservation Park, Kangaroo Island, South Australia. Ten different mother/pup pairs were equipped at three stages of development (6, 15 and 23 months) to record the diving behaviours of 51 (nine instruments failed) animals.
Dive depth and duration increased with age. However, development was slow. At 6 months, pups demonstrated minimal diving activity and the mean depth for 23‐month‐old juveniles was only 44 ± 4 m, or 62% of adult mean depth.
Although pups and juveniles did not reach adult depths or durations, dive records for young sea lions indicate benthic diving with mean bottom times (2·0 ± 0·2 min) similar to those of females (2·1 ± 0·2 min). This was accomplished by spending higher proportions of each dive and total time at sea on or near the bottom than adults. Immature sea lions also spent a higher percentage of time at sea diving.
Juveniles may have to work harder because they are weaned before reaching full diving capability. For benthic foragers, reduced diving ability limits available foraging habitat. Furthermore, as juveniles appear to operate close to their physiological maximum, they would have a difficult time increasing foraging effort in response to reductions in prey. Although benthic prey are less influenced by seasonal fluctuations and oceanographic perturbations than epipelagic prey, demersal fishery trawls may impact juvenile survival by disrupting habitat and removing larger size classes of prey. These issues may be an important factor as to why the Australian sea lion population is currently at risk.
Abiotic factors control invasion by Argentine ants at the community scale
Authors: MENKE SEAN B. , HOLWAY DAVID A. 
Published: March 2006

Summary

A prominent and unresolved question in ecology concerns why communities differ in their susceptibility to invasion. While studies often emphasize biotic resistance, it is less widely appreciated how the physical environment affects community vulnerability to invasion.
In this study we performed field experiments to test how abiotic variation directly and indirectly influences the extent to which Linepithema humile Mayr (Argentine ants) invade seasonally dry environments in southern California.
In controlled and replicated experiments involving drip irrigation, we demonstrate (i) that elevated levels of soil moisture increased both the abundance of Argentine ants and their ability to invade native ant communities and (ii) that cessation of irrigation caused declines in the abundance of Argentine ants and led to their withdrawal from previously occupied areas.
Because drip irrigation stimulated plant growth, in an additional experiment we manipulated both soil moisture and plant cover to assess the direct vs. indirect effects of added water on the abundance of L. humile.
Local abundance of Argentine ants increased in irrigated plots but was 38% higher in irrigated plots with plants compared to irrigated plots where plant growth was suppressed. The results of this experiment thus argue for a direct role of soil moisture in influencing Argentine ant abundance but suggest that that the indirect effects of added water may also be important.
Our study illustrates more generally that fine‐scale variation in the physical environment can control whether communities become invaded by non‐native species and suggests that an understanding of community susceptibility to invasion will be improved by a better appreciation of interactions between the biotic and abiotic environment.
Stomach temperature telemetry reveals temporal patterns of foraging success in a free‐ranging marine mammal
Authors: AUSTIN DEBORAH , BOWEN W. D. , MCMILLAN J. I. , BONESS D. J. 
Published: March 2006

Summary

We studied feeding frequency in free‐ranging grey seals using stomach temperature telemetry to test if previously reported sex differences in the diving, movement and diet were reflected in the temporal pattern of foraging success.
Data were retrieved from 21 of 32 grey seals from 1999 to 2001, totalling 343 days and 555 feeding events, with individual record length varying from 2 to 40 days (mean: 16·33 ± 2·67 days/seal).
Seals fed on 57·8 ± 6·46% of days sampled and had an average of 1·7 ± 0·26 meals per day, but individual variability was apparent in the temporal distribution of feeding as evidenced by high coefficients of variation (coefficient of variation = 69·0%).
Bout analysis of non‐feeding intervals of six grey seals suggests that feeding intervals of individuals were varied and probably reflect differences in prey availability. Grey seals tended to have many single feeding events with long periods separating each event, as would be expected for a large carnivore with a batch‐reactor digestive system.
We found significant sex differences in the temporal distribution of feeding. The number of feeding events per day was greater in males (2·2 ± 0·4 vs. 1·0 ± 0·2), as was time associated with feeding per day (56·6 ± 5·8 min vs. 43·9 ± 9·4 min).
The number of feeding events varied with time of day with the least number occurring during dawn. Feeding event size differed significantly by time of day, with greater meal sizes during the dawn and the smallest meals during the night.
The length of time between meals increased with the size of the previous meal, and was significantly less in males (541·4 ± 63·5 min) than in females (1092·6 ± 169·9 min).
These results provide new insight into the basis of sex differences in diving and diet in this large size‐dimorphic marine predator.
Sequentially assembled food webs and extremum principles in ecosystem ecology
Authors: VIRGO NATHANIEL , LAW RICHARD , EMMERSON MARK 
Published: March 2006

Summary

Successional changes during sequential assembly of food webs were examined. This was carried out by numerical methods, drawing one species at a time from a species pool and obtaining the permanent (persistent) community emerging at each step. Interactions among species were based on some simple rules about body sizes of consumers and their prey, and community dynamics were described in terms of flows of biomass density.
Sequential assembly acted as a sieve on the communities, assembled communities having many properties different on average from those of feasible, stable communities taken at random from the species pools.
Time‐series of community development were consistent with certain functions thought to go to an extremum (maximum or minimum) in ecosystem ecology, including a rapid early increase in net primary productivity and ascendency, although a clear trend in total biomass density was not evident and resilience decreased rather than increased.
In addition, more gradual changes in food web structure took place during succession to which the ecosystem goal functions were relatively insensitive. These changes included gradual increases in the number of species, invasion resistance, number of loops of length > 2 and number of prey species per consumer species.
We therefore argue that ecosystem and community dynamics can offer complementary insights into the process of ecological succession. The extremum principles of ecosystem ecology highlight some of the major properties of succession, whereas the community ecology sheds light on some more subtle changes taking place within the networks.