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1.
Sci Adv ; 7(7)2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33579714

RESUMO

Hydrogel physical properties are tuned by altering synthesis conditions such as initial polymer concentration and polymer-cross-linker stoichiometric ratios. Traditionally, differences in hydrogel synthesis schemes, such as end-linked poly(ethylene glycol) diacrylate hydrogels and cross-linked poly(vinyl alcohol) hydrogels, limit structural comparison between hydrogels. In this study, we use generalized synthesis variables for hydrogels that emphasize how changes in formulation affect the resulting network structure. We identify two independent linear correlations between these synthesis variables and swelling behavior. Analysis through recently updated swollen polymer network models suggests that synthesis-swelling correlations can be used to make a priori predictions of the stiffness and solute diffusivity characteristics of synthetic hydrogels. The same experiments and analyses performed on methacrylamide-modified gelatin hydrogels demonstrate that complex biopolymer structures disrupt the linear synthesis-swelling correlations. These studies provide insight into the control of hydrogel physical properties through structural design and can be used to implement and optimize biomedically relevant hydrogels.

2.
Insect Mol Biol ; 28(5): 689-702, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30955213

RESUMO

The two tephritid fruit fly pests, Bactrocera tryoni and Bactrocera neohumeralis, are unusually well suited to the study of the genetics of reproductive isolating mechanisms. Sequence difference between the species is no greater than between a pair of conspecific Drosophila melanogaster populations. The two species exist in close sympatry, yet do not hybridize in the field, apparently kept separate by a strong premating isolation mechanism involving the time of day at which mating occurs. This spurred us to search for key genes for which time of day expression is regulated differently between the species. Using replicated, quantitative transcriptomes from head tissues of males of the two species, sampled in the day and night, we identified 141 transcripts whose abundance showed a significant interaction between species and time of day, indicating a difference in gene regulation. The brain transcripts showing this interaction were enriched for genes with a neurone function and 90% of these were more abundant at night than day in B. tryoni. Features of the expression patterns suggest that there may be a difference in the regulation of sleep-wake cycles between the species. In particular several genes, which in D. melanogaster are expressed in circadian pacemaker cells, are promising candidates to further explore the genetic differentiation involved in this prezygotic reproductive isolation mechanism.


Assuntos
Isolamento Reprodutivo , Comportamento Sexual Animal , Tephritidae/genética , Animais , Encéfalo/metabolismo , Ritmo Circadiano/genética , Ritmo Circadiano/fisiologia , Regulação da Expressão Gênica , Genes de Insetos , Locomoção , Masculino , Especificidade da Espécie , Tephritidae/fisiologia , Transcriptoma
3.
Evolution ; 70(1): 229-34, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26639450

RESUMO

Comparison of the genomes of different Drosophila species has shown that six different chromosomes, the so-called ''Muller elements," constitute the building blocks for all Drosophila species. Here, we confirm previous results suggesting that this conservation of the Muller elements extends far beyond Drosophila, to at least tephritid fruit flies, thought to have diverged from drosophilids 60-70 mYr ago. Less than 10 percent of genes differ in chromosome location between the two insect groups. Within chromosomes, however, the order is highly scrambled, as expected from the comparison between Drosophila species. The data also support the notion that the sex chromosomes of tephritid flies originated from an ancestor of the dot chromosome 4 of Drosophila. Overall, therefore, no new chromosome has been created for perhaps a billion generations over the two evolutionary lines. This stability at the chromosome level, which appears to extend to all Diptera including mosquitoes, is in stark contrast to other groups such as mammals, birds, fish and plants, in which chromosome numbers and organization vary enormously among species that have diverged over much fewer generations.


Assuntos
Cromossomos de Insetos , Dípteros/genética , Evolução Molecular , Animais , Drosophila/genética , Cromossomos Sexuais/genética , Tephritidae/genética
4.
Phys Rev Lett ; 114(9): 090402, 2015 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-25793785

RESUMO

We fully characterize the reduced dynamics of an open quantum system initially correlated with its environment. Using a photonic qubit coupled to a simulated environment, we tomographically reconstruct a superchannel-a generalized channel that treats preparation procedures as inputs-from measurement of the system alone. We introduce novel quantitative measures for determining the strength of initial correlations, and to allow an experiment to be optimized in regard to its environment.

5.
BMC Genet ; 15 Suppl 2: S9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25470996

RESUMO

Among Australian endemic tephritid fruit flies, the sibling species Bactrocera tryoni and Bactrocera neohumeralis have been serious horticultural pests since the introduction of horticulture in the nineteenth century. More recently, Bactrocera jarvisi has also been declared a pest in northern Australia. After several decades of genetic research there is now a range of classical and molecular genetic tools that can be used to develop improved Sterile Insect Technique (SIT) strains for control of these pests. Four-way crossing strategies have the potential to overcome the problem of inbreeding in mass-reared strains of B. tryoni. The ability to produce hybrids between B. tryoni and the other two species in the laboratory has proved useful for the development of genetically marked strains. The identification of Y-chromosome markers in B. jarvisi means that male and female embryos can be distinguished in any strain that carries a B. jarvisi Y chromosome. This has enabled the study of homologues of the sex-determination genes during development of B jarvisi and B. tryoni, which is necessary for the generation of genetic-sexing strains. Germ-line transformation has been established and a draft genome sequence for B. tryoni released. Transcriptomes from various species, tissues and developmental stages, to aid in identification of manipulation targets for improving SIT, have been assembled and are in the pipeline. Broad analyses of the microbiome have revealed a metagenome that is highly variable within and across species and defined by the environment. More specific analyses detected Wolbachia at low prevalence in the tropics but absent in temperate regions, suggesting a possible role for this endosymbiont in future control strategies.


Assuntos
Animais Geneticamente Modificados , Biotecnologia , Dípteros/genética , Infertilidade/genética , Animais , Austrália , Feminino , Perfilação da Expressão Gênica , Marcadores Genéticos , Genoma de Inseto , Masculino , Fatores Sexuais
6.
BMC Genet ; 15 Suppl 2: S7, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25472807

RESUMO

BACKGROUND: Developing embryos are provided with maternal RNA transcripts and proteins, but transcription from the zygotic nuclei must be activated to control continuing embryonic development. Transcripts are generated at different stages of early development, and those involved in sex determination and cellularisation are some of the earliest to be activated. The male sex in tephritid fruit flies is determined by the presence of a Y chromosome, and it is believed that a transcript from the Y-chromosome sets in motion a cascade that determines male development, as part of the greater maternal to zygotic transition (MTZ). Here we investigate the poly(A+) transcriptome in early male and female embryos of the horticultural pest Bactrocera jarvisi (Diptera: Tephritidae). RESULTS: Bactrocera jarvisi embryos were collected over two pre-blastoderm time periods, 2-3h and 3-5h after egg laying. Embryos were individually sexed using a Y-chromosome marker, allowing the sex-specific poly(A+) transcriptome of single-sex embryo pools to be deep-sequenced and assembled de novo. Transcripts for sixteen sex-determination and two cellularisation gene homologues of Drosophila melanogaster (Diptera: Drosophilidae) were identified in early embryos of B. jarvisi, including transcripts highly upregulated prior to cellularisation. No strong candidates for transcripts derived solely from the Y chromosome were recovered from the poly(A+) fraction. CONCLUSIONS: Bactrocera jarvisi provides an excellent model for embryonic studies due to available Y-chromosome markers and the compact time frame for zygotic transcription and the sex-determined state. Our data contribute fundamental information to sex-determination research, and provide candidates for the sourcing of gene promoters for transgenic pest-management strategies of tephritid fruit flies.


Assuntos
Dípteros/genética , Embrião não Mamífero , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Transcriptoma , Animais , Biologia Computacional , Mineração de Dados , Feminino , Masculino , Anotação de Sequência Molecular , Reprodutibilidade dos Testes , Fatores Sexuais
7.
Br J Pharmacol ; 171(22): 5127-38, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24990525

RESUMO

BACKGROUND AND PURPOSE: Investigators have suggested that the chemokine receptor CCR1 plays a role in multiple myeloma. Studies using antisense and neutralizing antibodies to CCR1 showed that down-regulation of the receptor altered disease progression in a mouse model. More recently, experiments utilizing scid mice injected with human myeloma cells demonstrated that the CCR1 antagonist BX471 reduced osteolytic lesions, while the CCR1 antagonist MLN-3897 prevented myeloma cell adhesion to osteoclasts. However, information is limited regarding the pharmacology of CCR1 antagonists in myeloma cells. EXPERIMENTAL APPROACH: We compared several well-studied CCR1 antagonists including AZD4818, BX471, CCX354, CP-481715, MLN-3897 and PS899877 for their ability to inhibit binding of [(125)I]-CCL3 in vitro using membranes prepared from RPMI 8226 cells, a human multiple myeloma cell line that endogenously expresses CCR1. In addition, antagonists were assessed for their ability to modulate CCL3-mediated internalization of CCR1 and CCL3-mediated cell migration using RPMI 8226 cells. As many GPCRs signal through ß-arrestin-dependent pathways that are separate and distinct from those driven by G-proteins, we also evaluated the compounds for their ability to alter ß-arrestin translocation. KEY RESULTS: There were clear differences between the CCR1 antagonists in their ability to inhibit CCL3 binding to myeloma cells, as well as in their ability to inhibit G-protein-dependent and -independent functional responses. CONCLUSIONS AND IMPLICATIONS: Our studies demonstrate that tissue phenotype seems to be relevant with regards to CCR1. Moreover, it appears that for CCR1 antagonists, inhibition of ß-arrestin translocation is not necessarily linked to chemotaxis or receptor internalization.


Assuntos
Receptores CCR1/antagonistas & inibidores , Receptores CCR1/metabolismo , Animais , Arrestinas/metabolismo , Células CHO , Linhagem Celular Tumoral , Quimiocina CCL3/metabolismo , Quimiotaxia , Cricetulus , Células HEK293 , Humanos , Mieloma Múltiplo , Compostos de Fenilureia/farmacologia , Piperidinas/farmacologia , Quinoxalinas/farmacologia , Ensaio Radioligante , Compostos de Espiro/farmacologia , beta-Arrestinas
8.
PLoS One ; 8(7): e69078, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23894410

RESUMO

There is a substantial literature on the use of linkage disequilibrium (LD) to estimate effective population size using unlinked loci. The Ne estimates are extremely sensitive to the sampling process, and there is currently no theory to cope with the possible biases. We derive formulae for the analysis of idealised populations mating at random with multi-allelic (microsatellite) loci. The 'Burrows composite index' is introduced in a novel way with a 'composite haplotype table'. We show that in a sample of diploid size S, the mean value of x2 or r2 from the composite haplotype table is biased by a factor of 1-1/(2S-1)2, rather than the usual factor 1+1/(2S-1) for a conventional haplotype table. But analysis of population data using these formulae leads to Ne estimates that are unrealistically low. We provide theory and simulation to show that this bias towards low Ne estimates is due to null alleles, and introduce a randomised permutation correction to compensate for the bias. We also consider the effect of introducing a within-locus disequilibrium factor to r2, and find that this factor leads to a bias in the Ne estimate. However this bias can be overcome using the same randomised permutation correction, to yield an altered r2 with lower variance than the original r2, and one that is also insensitive to null alleles. The resulting formulae are used to provide Ne estimates on 40 samples of the Queensland fruit fly, Bactrocera tryoni, from populations with widely divergent Ne expectations. Linkage relationships are known for most of the microsatellite loci in this species. We find that there is little difference in the estimated Ne values from using known unlinked loci as compared to using all loci, which is important for conservation studies where linkage relationships are unknown.


Assuntos
Drosophila , Desequilíbrio de Ligação , Modelos Genéticos , Animais , Simulação por Computador , Drosophila/genética , Ligação Genética , Genética Populacional , Repetições de Microssatélites , Densidade Demográfica
9.
J Chem Phys ; 138(21): 214307, 2013 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-23758371

RESUMO

(2 + 1) resonance enhanced multiphoton ionization in combination with time-of-flight mass spectroscopy (TOF-MS) has been used to detect both the O((3)P) and O((1)D) fragments produced as a result of predissociation of the C (3)Πg (v = 0) and (v = 1) Rydberg states of O2, accessed via two-photon absorption from the ground X (3)Σg(-) state. In particular, TOF profiles have been recorded at various fixed two-photon absorption wavelengths within the two bands, with circular polarized probe laser light used to probe the angular momentum orientation of these photofragments. All photofragments are found to display coherent orientation resulting from interference between two possible two-photon absorption pathways. The measured orientation is affected by rotational depolarization due to the long lifetime of the excited C state; once this effect is accounted for the orientation is found to be nearly constant over all dissociation wavelengths. The origin of the coherent orientation is attributed to two-photon absorption to different spin-orbit components of the C state.

10.
J Chem Phys ; 138(10): 104320, 2013 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-23514502

RESUMO

(2+1) resonance enhanced multiphoton ionization time-of-flight mass spectroscopy (TOF-MS) has been used to detect both the O((3)P) and O((1)D) fragments produced as a result of predissociation of the C (3)Πg (v = 0) and (v = 1) Rydberg states of O2. In particular, TOF profiles have been recorded at various fixed wavelengths within the two bands in order to investigate the differences in predissociation dynamics of intermediate levels with different values of |Ω| (=0, 1, 2 in this case). TOF profiles have been recorded in multiple geometries to determine both the translational anisotropy and angular momentum alignment of both photofragments as well as the O((3)P) spin-orbit branching ratios produced following a two-photon dissociation. The translational anisotropy is found to be dependent on the dissociation wavelength with the variations found to be consistent with rotational depolarization due to the long lifetime of the excited C state. All photofragments have been found to be aligned, with the relationship between the measured O((3)P) and O((1)D) alignment being found to be consistent with a diabatic model of the dissociation.

11.
J Econ Entomol ; 105(3): 1051-6, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22812147

RESUMO

Tephritid fruit flies, an important pest of horticulture worldwide, are increasingly targeted for control or eradication by large-scale releases of sterile flies of the same species. For each species treated, strains must be domesticated for mass rearing to provide sufficiently large numbers of individuals for releases. Increases in productivity of domesticated tephritid strains are well documented, but there have been few systematic studies of the genetic consequences of domestication in tephritids. Here, we used nine DNA microsatellite markers to monitor changes in genetic diversity during the early generations of domestication in replicated lines of the fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). The observed changes in heterozygosity and allelic richness were compared with the expected changes in heterozygosity generated by a stochastic simulation including genetic drift but not selection. The results showed that repeatable genetic bottlenecks occur in the early generations and that selection occurs in the later generations. Furthermore, using the same simulation, we show that there is inadvertent selection for increased productivity for the entire life on a mass-rearing colony, in addition to intentional selection for increased productivity. That additional selection results from the common practice of establishing the next generation of the breeding colony from a small proportion of one day's pupae collection (the pupal raffle). That selection occurs during all generations and acts only on fecundity variation. Practical methods to counter that unavoidable loss of genetic diversity during the domestication process in B. tryoni are discussed.


Assuntos
Técnicas de Cultura , Oviparidade/genética , Seleção Genética , Tephritidae/genética , Animais , Feminino , Fertilidade/genética , Masculino , Repetições de Microssatélites
12.
J Chem Phys ; 136(16): 164311, 2012 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-22559486

RESUMO

Velocity mapped ion imaging and resonantly enhanced multiphoton ionization time-of-flight methods have been used to investigate the photodissociation dynamics of the diatomic molecule Cl(2) following excitation to the first UV absorption band. The experimental results presented here are compared with high level time dependent wavepacket calculations performed on a set of ab initio potential energy curves [D. B. Kokh, A. B. Alekseyev, and R. J. Buenker, J. Chem. Phys. 120, 11549 (2004)]. The theoretical calculations provide the first determination of all dynamical information regarding the dissociation of a system of this complexity, including angular momentum polarization. Both low rank K = 1, 2 and high rank K = 3 electronic polarization are predicted to be important for dissociation into both asymptotic product channels and, in general, good agreement is found between the recent theory and the measurements made here, which include the first experimental determination of high rank K = 3 orientation.

13.
Br J Pharmacol ; 167(1): 80-94, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22519452

RESUMO

BACKGROUND AND PURPOSE: Recently, a small molecule (Q94) was reported to selectively block PAR(1) /Gα(q) interaction and signalling. Here, we describe the pharmacological properties of Q94 and two analogues that share its benzimidazole scaffold (Q109, Q89). Q109 presents a modest variation from Q94 in the substituent group at the 2-position, while Q89 has quite different groups at the 1- and 2-positions. EXPERIMENTAL APPROACH: Using human microvascular endothelial cells, we examined intracellular Ca(2+) mobilization and inositol 1,4,5-trisphosphate accumulation as well as isoprenaline- or forskolin-stimulated cAMP production in response to thrombin. KEY RESULTS: Q89 (10 µM) produced a leftward shift in the thrombin-mediated intracellular Ca(2+) mobilization concentration-response curve while having no effect on the E(max) . Both Q94 (10 µM) and Q109 (10 µM) reduced intracellular Ca(2+) mobilization, leading to a decrease in E(max) and an increase in EC(50) values. Experiments utilizing receptor-specific activating peptides confirmed that Q94 and Q109 were selective for PAR(1) as they did not alter the Ca(2+) response mediated by a PAR(2) activating peptide. Consistent with our Ca(2+) results, micromolar concentrations of either Q94 or Q109 significantly reduced thrombin-induced inositol 1,4,5-trisphosphate production. Neither Q94 nor Q109 diminished the inhibitory effects of thrombin on cAMP production, indicating they inhibit signalling selectively through the G(q) pathway. Our results also suggest the 1,2-disubstituted benzimidazole derivatives act as 'allosteric agonists' of PAR(1) . CONCLUSIONS AND IMPLICATIONS: The Q94 and Q109 benzimidazole derivatives represent a novel scaffold for the development of new PAR(1) inhibitors and provide a starting point to develop dual signalling pathway-selective positive/negative modulators of PAR(1) .


Assuntos
Benzimidazóis/farmacologia , Receptor PAR-1/metabolismo , Cálcio/metabolismo , Linhagem Celular , Colforsina/farmacologia , AMP Cíclico/metabolismo , Humanos , Inositol 1,4,5-Trifosfato/metabolismo , Isoproterenol/farmacologia , Receptor PAR-1/agonistas , Transdução de Sinais/efeitos dos fármacos
14.
J Clin Pharm Ther ; 36(1): 1-9, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21198715

RESUMO

WHAT IS KNOWN AND BACKGROUND: The introduction of vaccines has lead to a significant reduction in morbidity and mortality from diseases such as measles, rubella and poliomyelitis, as well as the eradication of smallpox (Ertl HC, Xiang Z (1996) The Journal of Immunology, 156, 3579-3582). A recent vaccine approved by the Food and Drug Administration (FDA) is the recombinant quadrivalent human papillomavirus (HPV) vaccine (Merck, Gardasil®). Concerns raised with this preventive measure include safety and efficacy issues as well as the financial implications. Furthermore, the use of the vaccine in women outside the currently approved age ranges and in adolescent boys and men has also been a source of debate. OBJECTIVE: A review of two licensed HPV vaccines (Gardasil, Merck and Cervarix, GalxoSmithKline) in the light of these issues. METHODS: Literature searches were conducted using the MEDLINE (1966-December 2008) and PubMed databases in addition to the Centers for Disease Control and Prevention website. Bibliographies of selected references were also evaluated for relevant articles. Published guidelines and press releases were utilized as were the manufacturer's package inserts. The collection of information for this review was limited to the most recently available human data. RESULTS AND DISCUSSION: The HPV quadrivalent vaccine has been effective in the management of HPV by preventing vaccine subtype-related persistent infection and precancerous lesions as evidenced by numerous clinical trials. It is also regarded as a generally safe and well-tolerated vaccine, based on an assessment of reported adverse events submitted through governmental databases and analyzed by independent researchers. The majority of adverse events were non-serious and the vaccine has not been conclusively implicated with serious events. The FDA continues to focus on routine post-marketing surveillance monitoring of reported adverse events. The bivalent vaccine has also been shown to be effective in reported trials. Its adverse effect profile also appears acceptable. WHAT IS NEW AND CONCLUSION: The HPV vaccines appear safe and effective. Additional clinical research on the vaccines on women outside the currently approved age ranges and in males is necessary. Studies on longer-term outcomes, including cervical cancer and the emergence of new viral genotypes are also necessary.


Assuntos
Alphapapillomavirus , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/efeitos adversos , Adolescente , Adulto , Envelhecimento , Vacinas Anticâncer/efeitos adversos , Vacinas Anticâncer/economia , Vacinas Anticâncer/uso terapêutico , Condiloma Acuminado/prevenção & controle , Custos de Medicamentos , Feminino , Vacina Quadrivalente Recombinante contra HPV tipos 6, 11, 16, 18 , Humanos , Masculino , Vacinas contra Papillomavirus/economia , Vacinas contra Papillomavirus/uso terapêutico , Lesões Pré-Cancerosas/prevenção & controle , Anos de Vida Ajustados por Qualidade de Vida , Vacinas Sintéticas/efeitos adversos , Vacinas Sintéticas/economia , Vacinas Sintéticas/uso terapêutico , Adulto Jovem
15.
Cell Signal ; 23(2): 380-8, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20940042

RESUMO

Parathyroid hormone (PTH) is the major hormone regulating bone remodeling. Binding of PTH to the PTH1 receptor (PTH1R), a heterotrimeric G protein coupled receptor (GPCR), can potentially trigger multiple signal transduction pathways mediated through several different G proteins. In this study, we employed G protein antagonist minigenes inhibiting Gα(s), Gα(q) or Gα12 to selectively dissect out which of these G proteins were responsible for effects of PTH(1-34) in targeted signaling and osteogenesis arrays consisting of 159 genes. Among the 32 genes significantly regulated by 24h PTH treatment in UMR-106 osteoblastic cells, 9 genes were exclusively regulated through G(s), 6 genes were solely mediated through G(q), and 3 genes were only controlled through G12. Such findings support the concept that there is some absolute specificity in downstream responses initiated at the G protein level following binding of PTH to the PTH1R. On the other hand, 6 PTH-regulated genes were regulated by both G(s) and G(q), 3 genes were regulated by both G(s) and G12, and 3 genes were controlled by G(s), G(q) and G12. These findings indicate potential overlapping or sequential interactions among different G protein-mediated pathways. In addition, two PTH-regulated genes were not regulated through any of the G proteins examined, suggesting that additional signaling mechanisms may be involved. Selectivity was largely maintained over a 2-48-hour time period. The minigene effects were mimicked by downstream inhibitors. The dissection of the differential effects of multiple G protein pathways on gene regulation provides a more complete understanding of PTH signaling in osteoblastic cells.


Assuntos
Subunidades alfa de Proteínas de Ligação ao GTP/antagonistas & inibidores , Osteoblastos/fisiologia , Hormônio Paratireóideo/fisiologia , Animais , Linhagem Celular , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Perfilação da Expressão Gênica , Osteogênese , Ratos , Receptor Tipo 1 de Hormônio Paratireóideo/fisiologia , Transdução de Sinais , Ativação Transcricional
16.
J Econ Entomol ; 103(4): 1071-9, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20857713

RESUMO

Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) or "Qfly," is the most serious horticultural pest in Australia, with a bioclimatic range that extends from the tropical north to the temperate south. Various Australian horticultural exports depend on certification that they originated from B. tryoni-free areas. To eliminate, rather than suppress, B. tryoni in production areas, a sterile insect technique (SIT) campaign directed at B. tryoni has been in operation in southeastern Australia since 1997. Like many other SIT programs around the world, the B. tryoni SIT program relies on fluorescent dust to mark the sterile insects. However, fluorescent dust marking does not provide 100% accuracy in the identification of sterile insects, as required where the aim is to declare regions completely free of fruit fly. Here, we show that novel mitochondrial markers can be introduced into a strain of B. tryoni by interspecies hybridization between B. tryoni and a related but well-differentiated species, Bactrocera jarvisi (Tryon), followed by backcrossing of the hybrid strain with the parental B. tryoni strain. These novel markers do not affect the viability of the strain as measured by pupation and eclosion rates. A simple polymerase chain reaction-based test is described that distinguishes the marked B. tryoni from wild B. tryoni. As required in practice, the test was shown to work reliably on DNA extracted from dead flies that had remained in field traps for up to two weeks.


Assuntos
Marcadores Genéticos , Hibridização Genética , Tephritidae/genética , Animais , Austrália , Sequência de Bases , Demografia , Variação Genética , Dados de Sequência Molecular , Especificidade da Espécie
17.
Bull Entomol Res ; 100(2): 197-206, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19602297

RESUMO

Since 1985, a new and serious fruit fly pest has been reported in northwestern Australia. It has been unclear whether this pest was the supposedly benign endemic species, Bactrocera aquilonis, or a recent introduction of the morphologically near-identical Queensland fruit fly, B. tryoni. B. tryoni is a major pest throughout eastern Australia but is isolated from the northwest region by an arid zone. In the present study, we sought to clarify the species status of these new pests using an extensive DNA microsatellite survey across the entire northwest region of Australia. Population differentiation tests and clustering analyses revealed a high degree of homogeneity within the northwest samples, suggesting that just one species is present in the region. That northwestern population showed minimal genetic differentiation from B. tryoni from Queensland (FST=0.015). Since 2000, new outbreaks of this pest fruit fly have occurred to the west of the region, and clustering analysis suggested recurrent migration from the northwest region rather than Queensland. Mitochondrial DNA sequencing also showed no evidence for the existence of a distinct species in the northwest region. We conclude that the new pest fruit fly in the northwest is the endemic population of B. aquilonis but that there is no genetic evidence supporting the separation of B. aquilonis and B. tryoni as distinct species.


Assuntos
Variação Genética , Tephritidae/classificação , Tephritidae/genética , Animais , Austrália , DNA Mitocondrial/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Feminino , Masculino , Dados de Sequência Molecular , Filogenia , Polimorfismo Genético , Especificidade da Espécie
18.
Heredity (Edinb) ; 105(2): 165-72, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19997126

RESUMO

Previous population genetic studies of the Queensland fruit fly, Bactrocera tryoni Froggatt (Diptera: Tephritidae), in its central range have shown barely detectable genetic differentiation across distances of almost 3000 km (F(st)=0.003). In this study, we investigated the genetic structuring of southern border populations of B. tryoni, in the region extending from the central population to the recently colonized southern range limit. The expectation was that marginal populations would be small, fragmented population sinks, with local adaptation limited by gene flow or drift. Unexpectedly, we found that the population at the southern extreme of the range was a source population, rather than a sink, for the surrounding region. This was shown by assignment testing of recent outbreaks in an adjoining quarantine area and by indirect migration estimates. Furthermore, populations in the region had formed a latitudinal cline in microsatellite allele frequencies, spanning the region between the central population and the southern range limit. The cline has formed within 250 generations of the initial invasion and appears stable between years. We show that there is restricted gene flow in the region and that effective population sizes are of the order of 10(2)-10(3). Although the cline may result from natural selection, neutral evolutionary processes may also explain our findings.


Assuntos
Migração Animal , Tephritidae/genética , Animais , Clima , Fluxo Gênico , Repetições de Microssatélites , Austrália do Sul , Tephritidae/fisiologia
19.
J Phys Chem A ; 112(20): 4531-6, 2008 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-18435531

RESUMO

Methyl iodide photolysis at 193 nm has been studied through probing the I((2)P(1/2)-(2)P(3/2)) transition in the atomic iodine photofragment using diode laser spectroscopy. The I((2)P(1/2)) quantum yield has been determined through two different diode laser techniques and then compared. Frequency-modulated diode laser based absorption spectroscopy was used to extract nascent Doppler lineshapes from which an I((2)P(1/2)) quantum yield of unity is inferred. However when diode laser gain/absorption measurements were made, an I((2)P(1/2)) quantum yield of 0.68 ± 0.04 was found. The reason for this discrepancy is shown to lie in the diode laser gain/absorption method. Molecular iodine is found to be formed during the experiment via atomic iodine recombination and then in turn dissociates to produce both I((2)P(1/2)) and I((2)P(3/2)), thus distorting the returned quantum yield. This conclusion is supported both by the reduction of the I((2)P(1/2)) quantum yield with number of photolysis laser shots when measured using this technique and by the presence of fluoresence which is shown to have excited-state lifetimes and quenching rates that are consistent with those previously measured for the D and D' states of molecular iodine.

20.
Phys Rev Lett ; 100(6): 060504, 2008 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-18352449

RESUMO

Quantum information carriers with higher dimension than the canonical qubit offer significant advantages. However, manipulating such systems is extremely difficult. We show how measurement-induced nonlinearities can dramatically extend the range of possible transforms on biphotonic qutrits-three-level quantum systems formed by the polarization of two photons in the same spatiotemporal mode. We fully characterize the biphoton-photon entanglement that underpins our technique, thereby realizing the first instance of qubit-qutrit entanglement. We discuss an extension of our technique to generate qutrit-qutrit entanglement and to manipulate any bosonic encoding of quantum information.

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