Sampling efficacy for the red imported fire ant Solenopsis invicta (Hymenoptera: Formicidae)

Cost-effective detection of invasive ant colonies before establishment in new ranges is imperative for the protection of national borders and reducing their global impact. We examined the sampling efficiency of food-baits and pitfall traps (baited and nonbaited) in detecting isolated red imported fire ant (Solenopsis invicta Buren) nests in multiple environments in Gainesville, FL. Fire ants demonstrated a significantly higher preference for a mixed protein food type (hotdog or ground meat combined with sweet peanut butter) than for the sugar or water baits offered. Foraging distance success was a function of colony size, detection trap used, and surveillance duration. Colony gyne number did not influence detection success. Workers from small nests (0- to 15-cm mound diameter) traveled no >3 m to a food source, whereas large colonies (>30-cm mound diameter) traveled up to 17 m. Baited pitfall traps performed best at detecting incipient ant colonies followed by nonbaited pitfall traps then food baits, whereas food baits performed well when trying to detect large colonies. These results were used to create an interactive model in Microsoft Excel, whereby surveillance managers can alter trap type, density, and duration parameters to estimate the probability of detecting specified or unknown S. invicta colony sizes. This model will support decision makers who need to balance the sampling cost and risk of failure to detect fire ant colonies.     

Worldwide host plants of the highly polyphagous, invasive Epiphyas postvittana (Lepidoptera: Tortricidae)

The light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is a highly successful biological invader. It was accidentally introduced to several countries including New Zealand, Hawaii, England, and California. Light brown apple moth attacks a wide range of crop plants and other woody and herbaceous plants, but a more comprehensive analysis of its host range is needed for risk assessments, to evaluate the likely economic and environmental impacts, and to enable targeting of particular plant species for detection surveys and treatments. We reviewed and synthesized the host range and host selection behavior of light brown apple moth by using information from Australia and invaded countries. The host range of light brown apple moth is determined by the behavior of both adult females and larvae. Females use visual, chemical and physical cues to choose host plants. Larvae are capable of limited active dispersal by walking and longer range dispersal by ballooning on silken strands; therefore, larvae also may need to select host plants. We review larval performance indicators across a range of plants. Based on our review, there are at least 545 plant species in 363 genera from 121 families that have been reported as hosts of light brown apple moth. Some plants were reported only once and need verification. Nevertheless, many host plant species and their wide phylogenetic range (from ferns to higher dicotyledons) indicates that light brown apple moth is one of the most polyphagous insects known. This information and our categorization of frequency of host use are valuable for incursion response and pest management activities.     

Experimental influence of pH on the early life-stages of sea urchins II: increasing parental exposure times gives rise to different responses

Many studies into the responses of early life-stages to ocean acidification utilise offspring obtained from parents reared under present-day conditions. Their offspring are directly introduced to altered-pH conditions. This study determined whether this approach is suitable by pre-exposing parent sea urchins (Psammechinus miliaris) to altered seawater pH (~1000?μatm) for several durations, spawning them and rearing their offspring to settlement. Parents acclimated when exposed to low seawater pH for extended periods (>42?d). Longer adult pre-exposures reduced larval survival and less competent offspring were removed from populations earlier than in controls. Control offspring were larger during earlier development stages (2–7?d), but smaller during later development stages (14?+?d) than offspring reared under low pH conditions. Juvenile settlement levels were similar across all treatments. After 17?d, offspring sourced from parents pre-exposed to low pH for 42 and 70?d were larger than those pre-exposed for 28?d and ambient sourced offspring directly transferred to low pH. These different responses show that the use of ambient derived offspring utilised in many studies is likely not an ideal approach when assessing larval development responses via morphometric measurements and survivorship prior to settlement. This study also suggests that calcifying organisms have capacities to acclimate and possibly adapt towards conditions beyond natural rates of ocean acidification.     

Light brown apple moth (Epiphyas postvittana) (Lepidoptera: Tortricidae) colonization of California

In response to the confirmed detection of the light brown apple moth, Epiphyas postvittana, in California, approximately 53,000 pheromone-baited Jackson traps were deployed and more than 246,000 males were caught (February 2007–February 2010). Approximately 46,000 manually entered catch records were corrected for errors and converted into catch per trap per day. As empty trap data (zeros) were not recorded, we added zeros between first and last catch for each trap based on the stated servicing period (~30,000), before analyzing for trends. Residual data error rate was estimated as 1.5 %. San Francisco and Santa Cruz counties had relatively high trap catches immediately upon trap set, and remained the leading population centers, while most other counties showed a more general trend of a slow build-up in catch over time (12 counties). An exponential increase in trap catch was observed in four counties with sufficient data. The pattern of spread indicated natural, as well as anthropogenic-assisted spread rates, with populations appearing well ahead of the invasion front. This jump dispersal is probably due to movement of host plants, unsurprising since eggs of this polyphagous moth are readily laid on foliage. There was evidence of seasonality in spread, probably linked to the phenology of the insect. There was a positive relationship between catch and known host tree preference, suggesting that trap placement in preferred hosts could add sensitivity to future surveys. Recommendations include the improved provision of data acquisition by telecommunications, standardization of data input, more archiving, and frequent analysis of trap catches. The rapid rate of population growth demonstrated in two counties and spread across many others supports the hypothesis of the recent arrival of E. postvittana in California.     

Influenza H5N1 virus infection of polarized human alveolar epithelial cells and lung microvascular endothelial cells

Background

Highly pathogenic avian influenza (HPAI) H5N1 virus is entrenched in poultry in Asia and Africa and continues to infect humans zoonotically causing acute respiratory disease syndrome and death. There is evidence that the virus may sometimes spread beyond respiratory tract to cause disseminated infection. The primary target cell for HPAI H5N1 virus in human lung is the alveolar epithelial cell. Alveolar epithelium and its adjacent lung microvascular endothelium form host barriers to the initiation of infection and dissemination of influenza H5N1 infection in humans. These are polarized cells and the polarity of influenza virus entry and egress as well as the secretion of cytokines and chemokines from the virus infected cells are likely to be central to the pathogenesis of human H5N1 disease.

Aim

To study influenza A (H5N1) virus replication and host innate immune responses in polarized primary human alveolar epithelial cells and lung microvascular endothelial cells and its relevance to the pathogenesis of human H5N1 disease.

Methods

We use an in vitro model of polarized primary human alveolar epithelial cells and lung microvascular endothelial cells grown in transwell culture inserts to compare infection with influenza A subtype H1N1 and H5N1 viruses via the apical or basolateral surfaces.

Results

We demonstrate that both influenza H1N1 and H5N1 viruses efficiently infect alveolar epithelial cells from both apical and basolateral surface of the epithelium but release of newly formed virus is mainly from the apical side of the epithelium. In contrast, influenza H5N1 virus, but not H1N1 virus, efficiently infected polarized microvascular endothelial cells from both apical and basolateral aspects. This provides a mechanistic explanation for how H5N1 virus may infect the lung from systemic circulation. Epidemiological evidence has implicated ingestion of virus-contaminated foods as the source of infection in some instances and our data suggests that viremia, secondary to, for example, gastro-intestinal infection, can potentially lead to infection of the lung. HPAI H5N1 virus was a more potent inducer of cytokines (e.g. IP-10, RANTES, IL-6) in comparison to H1N1 virus in alveolar epithelial cells, and these virus-induced chemokines were secreted onto both the apical and basolateral aspects of the polarized alveolar epithelium.

Conclusion

The predilection of viruses for different routes of entry and egress from the infected cell is important in understanding the pathogenesis of influenza H5N1 infection and may help unravel the pathogenesis of human H5N1 disease.     

The Anabolic Androgenic Steroid Nandrolone Decanoate Disrupts Redox Homeostasis in Liver,Heart and Kidney of Male Wistar Rats

The abuse of anabolic androgenic steroids (AAS) may cause side effects in several tissues. Oxidative stress is linked to the pathophysiology of most of these alterations, being involved in fibrosis, cellular proliferation, tumorigenesis, amongst others. Thus, the aim of this study was to determine the impact of supraphysiological doses of nandrolone decanoate (DECA) on the redox balance of liver, heart and kidney. Wistar male rats were treated with intramuscular injections of vehicle or DECA (1 mg.100 g⁻¹ body weight) once a week for 8 weeks. The activity and mRNA levels of NADPH Oxidase (NOX), and the activity of catalase, glutathione peroxidase (GPx) and total superoxide dismutase (SOD), as well as the reduced thiol and carbonyl residue proteins, were measured in liver, heart and kidney. DECA treatment increased NOX activity in heart and liver, but NOX2 mRNA levels were only increased in heart. Liver catalase and SOD activities were decreased in the DECA-treated group, but only catalase activity was decreased in the kidney. No differences were detected in GPx activity. Thiol residues were decreased in the liver and kidney of treated animals in comparison to the control group, while carbonyl residues were increased in the kidney after the treatment. Taken together, our results show that chronically administered DECA is able to disrupt the cellular redox balance, leading to an oxidative stress state.     

Defining Interaction between Electroantennogram Responses of Epiphyas postvittana (lepidoptera: Tortricidae) to Pheromone and Other Volatiles

The potential for electroantennograms (EAGs) to assist in the measurement of atmospheric pheromone concentrations was examined in laboratory and field experiments by using multiple stimuli, the main component of the pheromone of Epiphyas postvittana, (E)-11-tetradecenyl acetate, its Z-isomer (a behavioral antagonist), and alpha-terpineol (a representative host-plant odor) were presented to the antenna simultaneously to simulate field conditions. The EAG results were compared with predictions from two models describing responses to combined stimuli. Responses are defined as log-additive if they can be described with the equation [EAG((total)) =a (log ([P(x)]+[B(y)])+c] and as linear-additive if the EAG follows the equation [EAG((total)) =a (log [P(x)])+c+a'(log [B(y)])+c'] where [B(y)] is the concentration of the stimulant background odor and [P(x)] is the concentration of an additional odor stimulus. The EAGs elicited by the added stimuli were inversely related to the concentration of the volatile in the background. EAGs elicited by all combined stimuli followed the log-additive model. Our laboratory results were validated in field tests; alpha-terpineol represents the volatiles present in orchard air. In spite of this interaction between the perception of pheromone and plant volatiles, the field EAG can be used for the measurement of atmospheric pheromone concentrations, where background odor concentrations are relatively constant.     

In vitro regulation of bovine adrenal cortical acyl-CoA: cholesterol acyltransferase and comparison with the rat liver enzyme

Acyl-CoA:cholesterol acyltransferase activity in bovine adrenal cortical microsomes was increased by preincubation of microsomes in vitro in the presence of MgCl2. The acyltransferase activity in the microsomes could be inhibited by further incubation in the presence of ATP/MgCl2. These effects appear to complement the known ATP-dependent activation of adrenal cytosolic cholesterol ester hydrolase, which is consistent with the role of the hydrolase in supplying cholesterol for steroidogenesis. These effects are, however, opposite to those recently demonstrated for the rat liver and intestine. Acyl-CoA:cholesterol acyltransferase activity in rat liver can be increased by the addition of cholesterol, as substrate, or by 25-hydroxycholesterol. Such activation was not observed in adrenal microsomal preparations, further suggesting that the mechanisms of regulation of cholesterol esterification differs between these tissues.     

Regulation of rat ovarian cell growth and steroid secretion

A cultured rat ovarian cell line (31 A-F(2)) was used to study the effect of growth factors (epidermal growth factor [EGF] and fibroblast growth factor [FGF]), a survival factor (ovarian growth factor [OGF]), a hormone (insulin), and an iron-binding protein (transferring) on cell proliferation and steroid production under defined culture conditions. EGF and insulin were shown to be mitogenic (half-maximal response at 0.12 nM and 0.11 muM, respectively) for 31A-F(2) cells incubated in serum-free medium. EGF induced up to three doublings in the cell population, whereas insulin induced an average of one cell population doubling. FGF, OGF, and transferrin were found not to have any prominent effect on cell division when incubated individually with 31A-F(2) cells in serum-free medium. However, a combination of EGF, OGF, insulin, and transferrin stimulated cell division to the same approximate extent as cells incubated in the presence of 5 percent fetal calf serum. EGF or insulin did not significantly affect total cell cholesterol levels (relative to cells incubated in serum-free medium) when incubated individually with 31A-F(2) cells. However, cell cholesterol levels were increased by the addition of OGF (250 percent), FGF (370 percent), or a combination of insulin and EGF (320 percent). Progesterone secretion from 31A-F(2) cells was enhanced by EGF (25 percent), FGF (80 percent), and insulin (115 percent). However, the addition of a mitogenic mixture of EGF, OGF, insulin, and transferrin suppressed progesterone secretion 150 percent) below that of control cultures. These studies have permitted us to determine that EGF and insulin are mitogenic factors that are required for the growth of 31A-F(2) cells and that OGF and transferrin are positive cofactors that enhance growth. Also, additional data suggest that cholesterol and progesterone production in 31A-F(2) cells can be regulated by peptide growth factors and the hormone insulin.