Lucilia cuprina is a parasitic fly of major economic importance worldwide. Larvae of this fly invade their animal host, feed on tissues and excretions and progressively cause severe skin disease (myiasis). Here we report the sequence and annotation of the 458-megabase draft genome of Lucilia cuprina. Analyses of this genome and the 14,544 predicted protein-encoding genes provide unique insights into the fly's molecular biology, interactions with the host animal and insecticide resistance. These insights have broad implications for designing new methods for the prevention and control of myiasis.
The Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae), is an important pest of sheep in Australia and other parts of the world. However, the paucity of information on many fundamental molecular aspects of this species limits the ability to exploit functional genomics techniques for the discovery of new drug targets for its control. The present study aimed to facilitate gene expression studies in this species by identifying the most suitable reference genes for normalization of mRNA expression data. Quantitative real-time polymerase chain reaction (PCR) was performed with 11 genes across RNA samples from eggs, L1, L3, pupae and adult life stages, and two normalization programs, Normfinder and geNorm, were then applied to the data. The results showed an ideal set of genes (18S rRNA, 28S rRNA, GST1, beta-tubulin and RPLPO) for data normalization across all life stages. The most suitable reference genes for studies within specific life stages were also identified. GAPDH was shown to be a poor reference gene. The reference gene recommendations in this study will be of use to laboratories investigating gene expression in L. cuprina and related blowfly species.
This study investigated the interaction of ATP binding cassette (ABC) transport proteins with ivermectin (IVM) and levamisole (LEV) in larvae of susceptible and resistant isolates of Haemonchus contortus in vitro by measuring transcription patterns following exposure to these anthelmintics. Furthermore, we studied the consequences of drug exposure by measuring the sensitivity of L3 to subsequent exposure to higher drug concentrations using larval migration assays. The most highly transcribed transporter genes in both susceptible and resistant L3 were pgp-9.3, abcf-1, mrp-5, abcf-2, pgp-3, and pgp-10. The resistant isolate showed significantly higher transcription of pgp-1, pgp-9.1 and pgp-9.2 compared to the susceptible isolate. Five P-gp genes and the haf-6 gene showed significantly higher transcription (up to 12.6-fold) after 3 h exposure to IVM in the resistant isolate. Similarly, five P-gp genes, haf-6 and abcf-1 were transcribed at significantly higher levels (up to 10.3-fold) following 3 h exposure to LEV in this isolate. On the other hand, there were no significant changes in transcriptional patterns of all transporter genes in the susceptible isolate following 3 and 6 h exposure to IVM or LEV. In contrast to these isolate-specific transcription changes, both isolates showed an increase in R-123 efflux following exposure to the drugs, suggesting that the drugs stimulated activity of existing transporter proteins in both isolates. Exposure of resistant larvae to IVM or LEV resulted, in some instances, in an increase in the proportion of the population able to migrate at the highest IVM concentrations in subsequent migration assays. The significant increase in transcription of some ABC transporter genes following 3 h exposure to both IVM and LEV in the resistant isolate only, suggests that an ability to rapidly upregulate protective pathways in response to drugs may be a component of the resistance displayed by this isolate.
In developing wheat grains (Triticum turgidum var.
durum cv. Fransawi), post-sieve element transport of
phloem-imported photoassimilates (sucrose) includes membrane transport, to and
from the grain apoplasm, between symplasmically-isolated maternal and filial
tissues. The cellular location and mechanism of these membrane transport steps
were explored during rapid grain fill. Genomic Southern analysis indicated the
presence of a multigene family of sucrose/H +
symporters (SUTs). One or more SUTs were highly expressed in developing
grains, as were P-type H + /ATPase(s) and a
sucrose binding protein (SBP). Transcripts of these genes were detected in
vascular parenchyma, nucellar projection and aleurone cells. Antibodies,
raised against a SUT, an H + /ATPase and a SBP,
were selectively bound to plasma membranes of vascular parenchyma cells,
nucellar projection transfer cells and modified aleurone/sub-aleurone
transfer cells. The nucellar projection transfer cells and modified
aleurone/sub-aleurone transfer cells exhibited strong proton pumping
activity. In contrast, SUT transport function was restricted to filial tissues
containing modified aleurone/sub-aleurone transfer cells. Based on these
findings, we conclude that SUTs expressed in maternal tissues do not function
as sucrose/H + symporters. Membrane exchange
from nucellar projection transfer cells to the endosperm cavity occurs by an
as yet unresolved mechanism. Sucrose uptake from the endosperm cavity into
filial tissues is mediated by a SUT localised to plasma membranes of the
modified aleurone/sub-aleurone transfer cells.
Internal transcribed spacer (ITS) sequences have been determined for a wide range of stipoid grasses (Poaceae, Pooideae, Stipeae). Nardus was confirmed as the most appropriate outgroup. Anisopogon is consistently included among the stipoid genera. Lithachne and Oryza form a clade and are clearly not close to Stipeae, and there is no support for including Brachyelytrum within Stipeae. Ampelodesmos and Diarrhena do appear among the core taxa in some analyses, but their positions are unstable and the evidence for retaining them is limited. So far there is inadequate support for rejecting them from Stipeae, so they should be included in any comprehensive study of the tribe. The ITS phylogeny supports a narrow interpretation of Jarava, one that includes only species with clear adaptations to anemophilous diaspore dispersal. There is no support for Achnatherum s.l. being a monophyletic group, nor are there any clear and consistent groups within it. Nassella, Hesperostipa, and Piptochaetium remain well supported. The data support some internal groupings within Nassella, but the sample size is small. It may be worthwhile investigating subgeneric relationships within Nassella. Anemanthele always appears associated with, and sometimes within, Austrostipa, but its position is inconsistent. We recommend continuing to recognize it at the generic level because of its distinctive morphological characters. Stipa s.s. shows some cohesion, but the results also suggest that some species currently included in the genus do not belong in it, suggestions that are supported by other studies. There has been no advance in understanding Piptatherum. The data support some of the subgeneric groupings within Austrostipa, but suggest that others should be combined. Austrostipa subgen. Falcateae is well supported, in part by a shared deletion. Additional species of Stipa s.s. and Piptatherum are being sequenced to broaden the sampling of these two genera.
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