Electroantennogram responses of the potato tuber moth, <Emphasis Type="Italic">Phthorimaea operculella</Emphasis> (Lepidoptera; Gelichiidae) to plant volatiles

Electroantennograms (EAGs)were recorded from males and females of the potato tuber moth,Phthorimaea operculella in response to a broad range of plant volatile compounds belonging to diverse chemical classes.The responses to 27 compounds were evaluated,which indicated significant differences in EAGs between chemicals as well as between sexes.The fatty acid derivatives comprising essentially green leaf volatile components elicited significantly greater responses in females.The response profile of males was,in general,lower than that of females.EAG responses to the oxygenated and hydrocarbon monoterpenes were lower in both males and females.Dose -response studies indicate differences in response between the sexes and concentrations,suggesting the existence of sexual dimorphism. Compounds belonging to the fatty acid derivatives class appear to be important for an oligophagous pest such as the potato tuber moth and the findings are discussed in relation to host plant selection in this species.     

A multi-trait systems approach reveals a response cascade to bleaching in corals

Background

Climate change causes the breakdown of the symbiotic relationships between reef-building corals and their photosynthetic symbionts (genus Symbiodinium), with thermal anomalies in 2015–2016 triggering the most widespread mass coral bleaching on record and unprecedented mortality on the Great Barrier Reef. Targeted studies using specific coral stress indicators have highlighted the complexity of the physiological processes occurring during thermal stress, but have been unable to provide a clear mechanistic understanding of coral bleaching.

Results

Here, we present an extensive multi-trait-based study in which we compare the thermal stress responses of two phylogenetically distinct and widely distributed coral species, Acropora millepora and Stylophora pistillata, integrating 14 individual stress indicators over time across a simulated thermal anomaly. We found that key stress responses were conserved across both taxa, with the loss of symbionts and the activation of antioxidant mechanisms occurring well before collapse of the physiological parameters, including gross oxygen production and chlorophyll a. Our study also revealed species-specific traits, including differences in the timing of antioxidant regulation, as well as drastic differences in the production of the sulfur compound dimethylsulfoniopropionate during bleaching. Indeed, the concentration of this antioxidant increased two-fold in A. millepora after the corals started to bleach, while it decreased 70% in S. pistillata.

Conclusions

We identify a well-defined cascading response to thermal stress, demarking clear pathophysiological reactions conserved across the two species, which might be central to fully understanding the mechanisms triggering thermally induced coral bleaching. These results highlight that bleaching is a conserved mechanism, but specific adaptations linked to the coral’s antioxidant capacity drive differences in the sensitivity and thus tolerance of each coral species to thermal stress.

     

Reproduction and nutritional stress are risk factors for Hendra virus infection in little red flying foxes (Pteropus scapulatus)

Hendra virus (HeV) is a lethal paramyxovirus which emerged in humans in 1994. Poor understanding of HeV dynamics in Pteropus spp. (flying fox or fruit bat) reservoir hosts has limited our ability to determine factors driving its emergence. We initiated a longitudinal field study of HeV in little red flying foxes (LRFF; Pteropus scapulatus) and examined individual and population risk factors for infection, to determine probable modes of intraspecific transmission. We also investigated whether seasonal changes in host behaviour, physiology and demography affect host-pathogen dynamics. Data showed that pregnant and lactating females had significantly higher risk of infection, which may explain previously observed temporal associations between HeV outbreaks and flying fox birthing periods. Age-specific seroprevalence curves generated from field data imply that HeV is transmitted horizontally via faeces, urine or saliva. Rapidly declining seroprevalence between two field seasons suggests that immunity wanes faster in LRFF than in other flying fox species, and highlights the potentially critical role of this species in interspecific viral persistence. The highest seroprevalence was observed when animals showed evidence of nutritional stress, suggesting that environmental processes that alter flying fox food sources, such as habitat loss and climate change, may increase HeV infection and transmission. These insights into the ecology of HeV in flying fox populations suggest causal links between anthropogenic environmental change and HeV emergence.     

LXR-α genomics programmes neuronal death observed in Alzheimer’s disease

Keeping in view the fact that the most pathognomonic feature of Alzheimer’s disease is the abnormal processing of neuronal cell membrane amyloid precursor protein accompanied by significantly elevated human serum and CSF levels of 24-hydroxycholesterol recognised widely as the specific endogenous ligand of Liver X receptor (LXR-α), the present study was addressed to explore the epigenomic-pathway (if any) that connects LXR-α activation with the genes recognised to be involved in the regulation of aberrant Abeta production leading to the generation of toxic and inflammatory mediators responsible for neuronal death. The results of such a study revealed that LXR-α activation by its specific endogenous or exogenous ligands within neuroblastoma cells resulted in the over-expression of PAR-4 gene accompanied by suppression of AATF gene through its inherent capacity to regulate genes coding for SREBP and NF-κB. Over-expression of PAR-4 gene was accompanied by aberrant Abeta production followed by ROS generation and subsequent death of neuroblastoma cells used in the present study as a cellular model for neurons. Further based upon these results, it was proposed that Abeta-induced heme oxygenase-1 can ensure cholesterol-oxidation to provide endogenous ligands for the sustained activation of neuronal LXR-α dependent epigenomic-pathway leading to neuronal death observed in Alzheimer’s disease.     

Hydroxynonenal,toxic carbonyls,and Alzheimer disease

Cytoskeletal disruption is one of the distinguishing characteristics of the vulnerable neurons in Alzheimer disease (AD). It has been suggested that these cytoskeletal changes occur secondarily to covalent modifications of the protein components. Despite the abundance and probable importance of these changes, there has been very little data regarding the identity of the modified proteins or the precise chemistry of the modifications. Here we review a specific type of modification, namely carbonylation of proteins, which has been shown to be a common result of cellular oxidative stress. Hopefully, the following discussion will help elucidate the relationship between oxidative stress, protein modification and the pathogenesis of AD.     

Proliferation-dependent expression of nuclear uracil-DNA glycosylase is mediated in part by E2F-4

There are two isoforms of the prototypical human uracil-DNA glycosylase: one mitochondrial (UDG1) and one nuclear (UDG1A). Results presented here reveal a novel genetic organization of UDG1. Specifically, the UDG1 5' UTR is composed of two non-coding exons and the promoter region is located much farther upstream than previously recognized. We also examine the proliferation-dependent expression of UDG1A and demonstrate that the protein disappears rapidly as cells transit from the cell cycle into G0. Ribonuclease protection assays reveal that UDG1A mRNA levels are greatly reduced during G0 as well. To begin to characterize the mechanisms contributing to this regulation, we identified two overlapping candidate E2F binding sites (denoted A and B) in the UDG1A 5' UTR. EMSA analysis of this region shows a unique protein complex present only in extracts derived from G0 cells. In vitro studies using purified E2F-4 and mutant competitors demonstrate that binding occurs in a proliferation-dependent manner exclusively to E2F site A. Two approaches were then used to assess the in vivo role of the candidate E2F sites. First, chromatin immunoprecipitation (ChIP) analysis demonstrates that E2F-4 binds to the UDG1A 5' UTR exclusively in G0 cells. Secondly, using transient transfection analysis, we show that mutating these sites abolishes the proliferation-dependent response of UDG1A.     

Rhamnolipid-Enhanced Mineralization of Phenanthrene in Organic-Metal Co-Contaminated Soils

Successful remediation of soils co-contaminated with organics and metals may require a combination of technologies. This research addresses the organic component within co-contaminated sites. It is well known that metal contaminants in soil can partially or completely inhibit normal heterotrophic microbial activity and hence prevent in situ biodegradation of organics. Previous work has shown that a rhamnolipid biosurfactant can complex metals such as lead and cadmium. It has also been demonstrated, in pure culture, that rhamnolipid can mitigate metal inhibition during the degradation of naphthalene. The goal of this study was to investigate whether rhamnolipid could reduce the toxicity of a model metal, cadmium, to indigenous soil populations in two different soils, Brazito and Gila, during the mineralization of phenanthrene. Results show that cadmium inhibited phenanthrene mineralization in both soils at bioavailable cadmium concentrations as low as 27 µM. This inhibition was reduced by the addition of rhamnolipid. Since rhamnolipid is degraded by soil populations, a rhamnolipid pulsing strategy was used to maintain a constant level of rhamnolipid in the system. Using this strategy, phenanthrene mineralization levels comparable to the control (0 mM Cd/0 mM rhamnolipid) were achieved in the presence of toxic cadmium concentrations. This research demonstrates that pulsed application of rhamnolipid may allow bioremediation of organic contaminants in sites that are co-contaminated with organics and metals.     

Assaying polymorphism at DNA level for genetic diversity diagnostics of the safflower (Carthamus tinctorius L.) world germplasm resources

Carthamus tinctorius (2n = 2x = 24), commonly known as safflower, is widely cultivated in agricultural production systems of Asia, Europe, Australia, and the Americas as a source of high quality vegetable and industrial oil. Twenty-two RAPD primers, 18 SSR primers, and 10 AFLP primer combinations were used to assess: (1) the genetic diversity of 85 accessions (originating from 24 countries) representing global germplasm variability of safflower and (2) the interrelationships among safflower ‘centers of similarity’ or ‘regional gene pools’ proposed earlier. The RAPD and SSR primers and AFLP primer combinations revealed 57.6, 68.0, and 71.2% polymorphism, respectively, among 111, 72, and 330 genetic loci amplified from the accessions. The sum of effective number of alleles (66.44), resolving power (59.16), and marker index (51.3) explicitly revealed the relative superiority of AFLP as a marker system in uncovering variation in safflower. Overall, AFLP markers could recognize ‘centers of similarity’ or ‘regional gene pools’. Analysis of molecular variance and Shannon’s information index provided corroborating evidences for the present and previous studies that concluded fragmentation of safflower gene pool into many gene pools. Divergent directional selection is likely to have played an important role in shaping the diversity. From the practical applications standpoint, the diversity of Iran–Afghanistan gene pool is very high, equivalent to the total diversity of the species. The Far East gene pool is the least diverse. The present comprehensive input, first of its own kind in safflower, will assist marker based improvement programmes in the crop.     

Sensitivity of methods for estimating breeding values using genetic markers to the number of QTL and distribution of QTL variance

The objective of this simulation study was to compare the effect of the number of QTL and distribution of QTL variance on the accuracy of breeding values estimated with genomewide markers (MEBV). Three distinct methods were used to calculate MEBV: a Bayesian Method (BM), Least Angle Regression (LARS) and Partial Least Square Regression (PLSR). The accuracy of MEBV calculated with BM and LARS decreased when the number of simulated QTL increased. The accuracy decreased more when QTL had different variance values than when all QTL had an equal variance. The accuracy of MEBV calculated with PLSR was affected neither by the number of QTL nor by the distribution of QTL variance. Additional simulations and analyses showed that these conclusions were not affected by the number of individuals in the training population, by the number of markers and by the heritability of the trait. Results of this study show that the effect of the number of QTL and distribution of QTL variance on the accuracy of MEBV depends on the method that is used to calculate MEBV.     

Fine needle aspiration of extramedullary myeloid cell tumor in myelodysplastic syndrome. A report of three cases.

BACKGROUND: Soft tissue tumors are rare in myelodysplastic syndrome (MDS), and the role of fine needle aspiration (FNA) cytology in their diagnosis has not been explored. CASES: Two patients with refractory anemia with excess blasts in transformation (RAEB-t) developed soft tissue swellings during the course of the illness. In a third patient, soft tissue swelling was a presenting feature. The swellings in all three cases were diagnosed as extramedullary myeloid cell tumor (EMT) on FNA and showed increased blasts (10-14%), dyspoietic changes, Auer rods and monocytosis. CONCLUSION: Soft tissue tumors appearing in MDS are likely to be EMTs. FNA is therefore particularly valuable in their diagnosis as morphology, cytochemistry, immunophenotyping and flow cytometric analysis of hematopoietic cells are best studied on aspirated material. We suggest that FNA be preferred over excisional biopsy for the diagnosis of soft tissue swellings in MDS.