Identification of a mutation in the para-sodium channel gene of the cattle tick Rhipicephalus (Boophilus) microplus associated with resistance to synthetic pyrethroid acaricides

Resistance against synthetic pyrethroid (SP) products for the control of cattle ticks in Australia was detected in the field in 1984, within a very short time of commercial introduction. We have identified a mutation in the domain II S4-5 linker of the para-sodium channel that is associated with resistance to SPs in the cattle tick Rhipicephalus (Boophilus) microplus from Australia. The cytosine to adenine mutation at position 190 in the R. microplus sequence AF134216, results in an amino acid substitution from leucine in the susceptible strain to isoleucine in the resistant strain. A similar mutation has been shown to confer SP resistance in the whitefly, Bemisia tabaci, but has not been described previously in ticks. A diagnostic quantitative PCR assay has been developed using allele-specific Taqman® minor groove-binding (MGB) probes. Using the assay to screen field and laboratory populations of ticks showed that homozygote allelic frequencies correlated highly with the survival percentage at the discriminating concentration of cypermethrin.

Ontogenetic depth partitioning by juvenile freshwater sawfish (Pristis microdon: Pristidae) in a riverine environment

The freshwater sawfish (Pristis microdon) is a critically endangered elasmobranch. Ontogenetic changes in the habitat use of juvenile P. microdon were studied using acoustic tracking in the Fitzroy River, Western Australia. Habitat partitioning was significant between 0+ (2007 year class) and larger 1+ (2006 year class) P. microdon. Smaller 0+ fish generally occupied shallower water (<0.6 m) compared with 1+ individuals, which mainly occurred in depths >0.6 m. Significant differences in hourly depth use were also revealed. The depth that 1+ P. microdon occupied was significantly influenced by lunar phase with these animals utilising a shallower and narrower depth range during the full moon compared with the new moon. This was not observed in 0+ individuals. Habitat partitioning was likely to be related to predator avoidance, foraging behaviours, and temperature and/or light regimes. The occurrence of 1+ P. microdon in deeper water may also result from a need for greater depths in which to manoeuvre. The present study demonstrates the utility of acoustic telemetry in monitoring P. microdon in a riverine environment. These results demonstrate the need to consider the habitat requirements of different P. microdon cohorts in the strategic planning of natural resources and will aid in the development of management strategies for this species.

Rapid Global Expansion of the Fungal Disease Chytridiomycosis into Declining and Healthy Amphibian Populations.

The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis, is enigmatic because it occurs globally in both declining and apparently healthy (non-declining) amphibian populations. This distribution has fueled debate concerning whether, in sites where it has recently been found, the pathogen was introduced or is endemic. In this study, we addressed the molecular population genetics of a global collection of fungal strains from both declining and healthy amphibian populations using DNA sequence variation from 17 nuclear loci and a large fragment from the mitochondrial genome. We found a low rate of DNA polymorphism, with only two sequence alleles detected at each locus, but a high diversity of diploid genotypes. Half of the loci displayed an excess of heterozygous genotypes, consistent with a primarily clonal mode of reproduction. Despite the absence of obvious sex, genotypic diversity was high (44 unique genotypes out of 59 strains). We provide evidence that the observed genotypic variation can be generated by loss of heterozygosity through mitotic recombination. One strain isolated from a bullfrog possessed as much allelic diversity as the entire global sample, suggesting the current epidemic can be traced back to the outbreak of a single clonal lineage. These data are consistent with the current chytridiomycosis epidemic resulting from a novel pathogen undergoing a rapid and recent range expansion. The widespread occurrence of the same lineage in both healthy and declining populations suggests that the outcome of the disease is contingent on environmental factors and host resistance.

Resistance to root-lesion nematodes (Pratylenchus thornei and P-neglectus) in synthetic hexaploid wheats and their durum and Aegilops tauschii parents.

Root-lesion nematodes (Pratylenchus thornei Sher and Allen and P. neglectus (Rensch) Filipijev and Schuurmans Stekhoven) cause substantial yield loss to wheat crops in the northern grain region of Australia. Resistance to P. thornei for use in wheat breeding programs was sought among synthetic hexaploid wheats (2n= 6x = 42, AABBDD) produced through hybridisations of Triticum turgidum L. subsp. durum (Desf.) Husn (2n= 4x = 28, AABB) with Aegilops tauschii Coss. (2n= 2x = 14, DD). Resistance was determined for the synthetic hexaploid wheats and their durum and Ae. tauschii parents from the numbers of nematodes in the roots of plants grown for 16 weeks in pots of pasteurised soil inoculated with P. thornei. Fifty-nine (32%) of 186 accessions of synthetic hexaploid wheats had lower numbers of nematodes than Gatcher Selection 50a (GS50a), a partially resistant bread wheat. Greater frequencies of partial resistance were present in the durum parents (72% of 39 lines having lower nematode numbers than GS50a) and in the Ae. tauschii parents (55% of 53 lines). The 59 synthetic hexaploids were re-tested in a second experiment along with their parents. In a third experiment, 11 resistant synthetic hexaploid wheats and their F-1 hybrids with Janz, a susceptible bread wheat, were tested and the F(1)s were found to give nematode counts intermediate between the respective two parents. Synthetic hexaploid wheats with higher levels of resistance resulted from hybridisations where both the durum and Ae. tauschii parents were partially resistant, rather than where only one parent was partially resistant. These results suggest that resistance to P. thornei in synthetic hexaploid wheats is polygenic, with resistances located both in the D genome from Ae. tauschii and in the A and/or B genomes from durum. Five synthetic hexaploid wheats were selected for further study on the basis of (1) a high level of resistance to P. thornei of the synthetic hexaploid wheats and of both their durum and Ae. tauschii parents, (2) being representative of both Australian and CIMMYT (International Maize and Wheat Improvement Centre) durums, and (3) being representative of the morphological subspecies and varieties of Ae. tauschii. These 5 synthetic hexaploid wheats were also shown to be resistant to P. neglectus, whereas GS50a and 2 P. thornei-resistant derivatives were quite susceptible. Results of P. thornei resistance of F(1)s and F(2)s from a half diallel of these 5 synthetic hexaploid wheats, GS50a, and Janz from another study indicate polygenic additive resistance and better general combining ability for the synthetic hexaploid wheats than for GS50a. Published molecular marker studies on a doubled haploid population between the synthetic hexaploid wheat with best general combining ability (CPI133872) and Janz have shown quantitative trait loci for resistance located in all 3 genomes. Synthetic hexaploid wheats offer a convenient way of introgressing new resistances to P. thornei and P. neglectus from both durum and Ae. tauschii into commercial bread wheats.

Cellular stages of root formation, root system quality and survival of Pinus elliottii var. elliottii x P. caribaea var. hondurensis cuttings in different temperature environments.

Time to first root in cuttings varies under different environmental conditions and understanding these differences is critical for optimizing propagation of commercial forestry species. Temperature environment (15, 25, 30 or 35 +/- A 2A degrees C) had no effect on the cellular stages in root formation of the Slash x Caribbean Pine hybrid over 16 weeks as determined by histology. Initially callus cells formed in the cortex, then tracheids developed and formed primordia leading to external roots. However, speed of development followed a growth curve with the fastest development occurring at 25A degrees C and slowest at 15A degrees C with rooting percentages at week 12 of 80 and 0% respectively. Cutting survival was good in the three cooler temperature regimes (> 80%) but reduced to 59% at 35A degrees C. Root formation appeared to be dependant on the initiation of tracheids because all un-rooted cuttings had callus tissue but no tracheids, irrespective of temperature treatment and clone.

Cellular stages of root formation, root system quality and survival of Pinuselliottii var. elliottii x P. caribaea var. hondurensis cuttings in different temperature environments.

Time to first root in cuttings varies under different environmental conditions and understanding these differences is critical for optimizing propagation of commercial forestry species. Temperature environment (15, 25, 30 or 352C) had no effect on the cellular stages in root formation of the Slash * Caribbean Pine hybrid over 16 weeks as determined by histology. Initially callus cells formed in the cortex, then tracheids developed and formed primordia leading to external roots. However, speed of development followed a growth curve with the fastest development occurring at 25C and slowest at 15C with rooting percentages at week 12 of 80 and 0% respectively. Cutting survival was good in the three cooler temperature regimes (>80%) but reduced to 59% at 35C. Root formation appeared to be dependant on the initiation of tracheids because all un-rooted cuttings had callus tissue but no tracheids, irrespective of temperature treatment and clone.

2-(p-Chlorophenyl)-3-nitro-2H-chromene

C15H10C1NO3, Mr=287.70, triclinic, PI, Z= 2, F(000)= 296, a = 5.422 (1), b = 9.624 (1), c= 12.636 (2) A, ~= 76.66 (2), fl= 78.67 (2), ~= 87.97 (2) ° , V=629.03 A 3, Din= 1.507 (3), Ox= 1.519Mgm -3, 2(CuKa)=l.5418A, p=26.25mm -~, T= 413 K, final R = 0.0577 for 1859 observed reflections [I>2.5e(/)]. Bond lengths [1.512(5)A] and angles [109.2 (3) °] at the phenyl substitution site are comparable with those in other molecules. The bond angle at the nitro substitution site C(7)-C(8)-C(9) is 122.9 (3) ° owing to the electron-withdrawing character of the nitro group. The pyran ring adapts a half-chair conformation.

Kinetics Of The Aminolysis Reactions Of Chlorocyclotriphosphazenes-Changeover From A Sn2(P) To A Sn1(P) Mechanism

A change-over from SN2(P) to SN1(P) mechanism is established for the chlorine replacement reactions of halogenocyclophosphazenes; this mechanistic change-over helps in rationalising the diverse findings reported for this class of reactions.

Specific detection of the Old World screwworm fly, Chrysomya bezziana, in bulk fly trap catches using real-time PCR.

The Old World screwworm fly (OWS), Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), is a myiasis-causing blowfly of major concern for both animals and humans. Surveillance traps are used in several countries for early detection of incursions and to monitor control strategies. Examination of surveillance trap catches is time-consuming and is complicated by the presence of morphologically similar flies that are difficult to differentiate from Ch. bezziana, especially when the condition of specimens is poor. A molecular-based method to confirm or refute the presence of Ch. bezziana in trap catches would greatly simplify monitoring programmes. A species-specific real-time polymerase chain reaction (PCR) assay was designed to target the ribosomal DNA internal transcribed spacer 1 (rDNA ITS1) of Ch. bezziana. The assay uses both species-specific primers and an OWS-specific Taqman MGB probe. Specificity was confirmed against morphologically similar and related Chrysomya and Cochliomyia species. An optimal extraction protocol was developed to process trap catches of up to 1000 flies and the assay is sensitive enough to detect one Ch. bezziana in a sample of 1000 non-target species. Blind testing of 29 trap catches from Australia and Malaysia detected Ch. bezziana with 100% accuracy. The probability of detecting OWS in a trap catch of 50 000 flies when the OWS population prevalence is low (one in 1000 flies) is 63.6% for one extraction. For three extractions (3000 flies), the probability of detection increases to 95.5%. The real-time PCR assay, used in conjunction with morphology, will greatly increase screening capabilities in surveillance areas where OWS prevalence is low.

Towards better management of Australia’s shark fishery: genetic analyses reveal unexpected ratios of cryptic blacktip species Carcharhinus tilstoni and C. limbatus

The common blacktip shark (Carcharhinus limbatus) and the Australian blacktip shark (C. tilstoni) are morphologically similar species that co-occur in subtropical and tropical Australia. In striking contrast to what has been previously reported, we demonstrate that the common blacktip shark is not rare in northern Australia but occurs in approximately equal frequencies with the Australian blacktip shark. Management of shark resources in northern Australia needs to take account of this new information. Species identification was performed using nucleotide sequences of the control, NADH dehydrogenase subunit 4 (ND4) and cytochrome oxidase I (COI) regions in the mitochondrial genome. The proportion of overall genetic variation (FST) between the two species was small (0.042, P < 0.01) based on allele frequencies at five microsatellite loci. We confirm that a third blacktip species (C. amblyrhynchoides, graceful shark) is closely related to C. tilstoni and C. limbatus and can be distinguished from them on the basis of mtDNA sequences from two gene regions. The Australian blacktip shark (C. tilstoni) was not encountered among 20 samples from central Indonesia that were later confirmed to be common blacktip and graceful sharks. Fisheries regulators urgently need new information on life history, population structure and morphological characters for species identification of blacktip shark species in Australia.

Critically endangered Pristis microdon (Elasmobranchii), as a host for the Indian parasitic copepod, Caligus furcisetifer Redkar, Rangnekar et Murti, 1949 (Siphonostomatoida): New records from northern Australia.

This paper presents the first records of the parasitic copepod Caligus furcisetifer Redkar, Rangnekar et Murti, 1949 beyond Indian waters, specifically, on the body surface and head of the critically endangered largetooth sawfish (commonly referred to as the freshwater sawfish in Australia), Pristis microdon Latham, 1794 (Elasmobranchii, Pristidae), in brackish tidal waters of the Fitzroy River in the Kimberley region of Western Australia and the Leichhardt River in the Gulf of Carpentaria in northern Queensland. This represents a geographic range extension of similar to 8000 km for this parasite. Further, it is only the second member of the genus Caligus to be found on an elasmobranch host in Western Australia and it is the first time this species has been reported from the Southern Hemisphere. Male biased dispersal of P microdon may be the vector in which the parasite has dispersed from India across to northern Australia, or vice versa. A decline in populations of the critically endangered P microdon (and possibly other pristid species) in these regions may lead to a concomitant decline in their parasite fauna.

Shared genetics underlying epidemiological association between endometriosis and ovarian cancer

Epidemiological studies have demonstrated associations between endometriosis and certain histotypes of ovarian cancer, including clear cell, low-grade serous and endometrioid carcinomas. We aimed to determine whether the observed associations might be due to shared genetic aetiology. To address this, we used two endometriosis datasets genotyped on common arrays with full-genome coverage (3194 cases and 7060 controls) and a large ovarian cancer dataset genotyped on the customized Illumina Infinium iSelect (iCOGS) arrays (10 065 cases and 21 663 controls). Previous work has suggested that a large number of genetic variants contribute to endometriosis and ovarian cancer (all histotypes combined) susceptibility. Here, using the iCOGS data, we confirmed polygenic architecture for most histotypes of ovarian cancer. This led us to evaluate if the polygenic effects are shared across diseases. We found evidence for shared genetic risks between endometriosis and all histotypes of ovarian cancer, except for the intestinal mucinous type. Clear cell carcinoma showed the strongest genetic correlation with endometriosis (0.51, 95% CI = 0.18–0.84). Endometrioid and low-grade serous carcinomas had similar correlation coefficients (0.48, 95% CI = 0.07–0.89 and 0.40, 95% CI = 0.05–0.75, respectively). High-grade serous carcinoma, which often arises from the fallopian tubes, showed a weaker genetic correlation with endometriosis (0.25, 95% CI = 0.11–0.39), despite the absence of a known epidemiological association. These results suggest that the epidemiological association between endometriosis and ovarian adenocarcinoma may be attributable to shared genetic susceptibility loci.

Population genetic structure and genetic diversity of three critically endangered Pristis sawfishes in Australian waters.

Northern Australia is considered to be one of the last strongholds for three critically endangered sawfishes, Pristis zijsron, Pristis clavata, and Pristis microdon, making these populations of global significance. Population structure and levels of genetic diversity were assessed for each species across northern Australia using a portion of the mitochondrial control region. Statistically significant genetic structure was detected in all three species, although it was higher in P. microdon (F-ST = 0.811; N = 149) than in either P. clavata (F-ST = 0.419; N = 73) or P. zijsron (F-ST = 0.202; N = 49), possibly due to a much higher and/or localized level of female philopatry in P. microdon. The overall levels of haplotype diversity in P. zijsron (h = 0.555), P. clavata (h = 0.489), and P. microdon (h = 0.650) were moderate, although it appears to be reduced in the assemblages of P. zijsron and P. clavata in the Gulf of Carpentaria (h = 0.342 and h = 0.083, respectively). Since female migration (replenishment) between regions is unlikely, conservation plans should strive to maintain current levels of diversity and abundances in the regional assemblages of each species.

Electrical transport in layered crystalline semiconductors GeS doped with Ag, P impurities at high pressure

A study of the transport properties of layered crystalline semiconductors GeS (undoped and doped with Ag, P impurity) under quasihydrostatic pressure using Bridgman anvil system is made for the first time. Pressure-induced effects in undoped crystals reveal initial rise in resistivity followed by two broad peaks at higher pressures. Silver doping induces only minor changes in the behaviour except removing the second peak. Phosphorous impurity is found to have drastic effect on the transport properties. Temperature dependence of the resistivity exhibits two activation energies having opposite pressure coefficients. Results are discussed in the light of intrinsic features of the layered semiconductors.

EUF-analysis of tea soils of Southern India and tea productivity

The relationship between EUF extractable nutrients and conventional soil test extractable nutrients in the acid soils of Southern India on one hand and that between EUF values and tea productivity on the other are described. Close correlation exists between EUF-NO3–N at 20°C and CuSO4–Ag2SO4-extractable NO3–N (r=0.98***), EUF-Norg and Morgan's reagent extractable NH4–N (r=0.97***), total EUF-N and CuSO4–Ag2SO4-extractable NO3–N plus Morgan's reagent NH4–N (r=0.96***), EUF-P at 20°C and modified Bray II-P (r=0.93***) and EUF-P at 20°C plus that at 80°C and modified Bray II-P (r=0.91***). The EUF-K at 20°C shows close correlation with NH4OAc–K (r=0.80***), Ag-thiourea-K (r=0.86***) and Morgan's reagent-K (r=0.84***) whereas the EUF-K at 80°C shows close correlation with the difference in K contents of NH4OAc–K and Ag-thiourea-K (r=0.92***) or of NH4OAc–K and Morgan's reagent-K (r=0.93***) and fixed NH4–N (r=0.89***). EUF-Ca, EUF-Mg and EUF-Mn do not show any relationship with conventional soil test values. Tea productivity is strongly associated with EUF-N and EUF-P extracted at 20°C.