Pollen limitation and xenia effects in a cultivated mass-flowering tree, Macadamia integrifolia (Proteaceae).

BACKGROUND AND AIMS: Pollen limitation is most prevalent among bee-pollinated plants, self-incompatible plants and tropical plants. However, we have very little understanding of the extent to which pollen limitation affects fruit set in mass-flowering trees despite tree crops accounting for at least 600 million tons of the 9200 million tons of annual global food production. METHODS: We determined the extent of pollen limitation in a bee-pollinated, partially self-incompatible, subtropical tree by hand cross-pollinating the majority of flowers on mass-flowering macadamia (Macadamia integrifolia) trees that produce about 200 000-400 000 flowers. We measured tree yield and kernel quality and estimated final fruit set. We genotyped individual kernels by MassARRAY to determine levels of outcrossing in orchards and assess paternity effects on nut quality. KEY RESULTS: Macadamia trees were pollen-limited. Supplementary cross-pollination increased nut-in-shell yield, kernel yield and fruit set by as much as 97, 109 and 92 %, respectively. The extent of pollen limitation depended upon the proximity of experimental trees to trees of another cultivar because macadamia trees were highly outcrossing. Between 84 and 100 % of fruit arose from cross-pollination, even at 200 m (25 rows) from orchard blocks of another cultivar. Large variations in nut-in-shell mass, kernel mass, kernel recovery and kernel oil concentration were related to differences in fruit paternity, including between self-pollinated and cross-pollinated fruit, thus demonstrating pollen-parent effects on fruit quality (i.e. xenia). CONCLUSIONS: This study is the first to demonstrate pollen limitation in a mass-flowering tree. Improved pollination led to increased kernel yield of 0.31-0.59 tons ha-1, which equates currently to higher farm-gate income of approximately $US3720-$US7080 ha-1. The heavy reliance of macadamia flowers on cross-pollination and the strong xenia effects on kernel mass demonstrate the high value that pollination services can provide to food production.

SNP markers reveal relationships between fruit paternity, fruit quality and distance from a cross-pollen source in avocado orchards.

Cross-pollination can improve fruit yield, fruit size and nutritional quality of many food crops. However, we rarely understand what proportions of the crop result from self- or cross-pollination, how cross-pollination affects crop quality, and how far pollen is transported by pollinators. Management strategies to improve pollination services are consequently not optimal for many crops. We utilised a series of SNP markers, unique for each cultivar of avocado, to quantify proportions of self- and cross-paternity in fruit of Hass avocado at increasing distances from cross-pollen sources. We assessed whether distance from a cross-pollen source determined the proportions of self-pollinated and cross-pollinated fruit, and evaluated how self- and cross-paternity affected fruit size and nutritional quality. Avocado fruit production resulted from both self- and cross-pollination in cultivar Hass in Queensland, Australia. Cross-pollination levels decreased with increasing distance from a cross-pollen source, from 63% in the row adjacent to another cultivar to 25% in the middle of a single-cultivar block, suggesting that pollen transport was limited across orchard rows. Limited pollen transport did not affect fruit size or quality in Hass avocados as xenia effects of a Shepard polliniser on size and nutritional quality were minor.

Human papillomavirus testing as part of the renewed National Cervical Screening Program.

BACKGROUND: On 1 December 2017, Australia moved to a new National Cervical Screening Program (NCSP), which uses primary human papillomavirus (HPV) nucleic acid testing (NAT) followed by reflex liquid-based cytology for women aged between 25 and 74 years. OBJECTIVE: The aim of this article is to provide an overview of the different HPV NAT assays that satisfy the requirements for use in the renewed NCSP. DISCUSSION: Australia has adopted innovative, evidence-based criteria for the inclusion of HPV NAT assays in the renewed NCSP. These include the requirements for detection of all 12 designated oncogenic HPV types, including separate detection and reporting of HPV 16 and 18; validation against reference assays showing sufficient sensitivity and specificity for the detection of underlying high-grade cervical disease; reproducibility; and the presence of cellularity and inhibition controls. Practitioners can feel assured that HPV NAT undertaken as part of the renewed NCSP will produce high­quality results irrespective of location or pathology provider.

Perspective: Scientific and ethical concerns pertaining to animal models of autoimmune/autoinflammatory syndrome induced by adjuvants (ASIA).

The autoimmune/autoinflammatory syndrome induced by adjuvants (ASIA) was first described in 2011. The aluminium containing adjuvants of vaccines were stated to be one of the main causes of the condition. Other disorders associated with ASIA include siliconosis, Gulf war syndrome, sick building syndrome and the macrophagic myositis syndrome. We have recently reviewed ASIA as defined by its authors. We have shown that the definition of ASIA is imprecise and includes all patients with an autoimmune disorder as well as potentially the entire population. Application of the Bradford Hill criteria for causality does not support ASIA as an outcome of exposure to aluminium containing adjuvants in vaccines. The advocates of ASIA highlight animal models as evidence for the existence of the disorder. However, as this review will demonstrate, animal models purporting to support the existence of ASIA have methodological, analytical and ethical flaws which, in our view, refute the existence of the condition. Three publications by the advocates of ASIA were recently retracted from peer-reviewed journals. We call for an immediate moratorium on animal experiments of ASIA until an independent inquiry has been conducted to determine the existence of a clinically relevant syndrome, identifiable as ASIA in humans.

The A-rich RNA sequences of HIV-1 pol are important for the synthesis of viral cDNA.

The bias of A-rich codons in HIV-1 pol is thought to be a record of hypermutations in viral genomes that lack biological functions. Bioinformatic analysis predicted that A-rich sequences are generally associated with minimal local RNA structures. Using codon modifications to reduce the amount of A-rich sequences within HIV-1 genomes, we have reduced the flexibility of RNA sequences in pol to analyze the functional significance of these A-rich 'structurally poor' RNA elements in HIV-1 pol. Our data showed that codon modification of HIV-1 sequences led to a suppression of virus infectivity by 5-100-fold, and this defect does not correlate with, viral entry, viral protein expression levels, viral protein profiles or virion packaging of genomic RNA. Codon modification of HIV-1 pol correlated with an enhanced dimer stability of the viral RNA genome, which was associated with a reduction of viral cDNA synthesis both during HIV-1 infection and in a cell free reverse transcription assay. Our data provided direct evidence that the HIV-1 A-rich pol sequence is not merely an evolutionary artifact of enzyme-induced hypermutations, and that HIV-1 has adapted to rely on A-rich RNA sequences to support the synthesis of viral cDNA during reverse transcription, highlighting the utility of using 'structurally poor' RNA domains in regulating biological process.