Agricultural insect hybridization and implications for pest management

Biological invasions, the expansion of agricultural frontiers, and climate change favor encounters of divergent lineages of animals and plants, increasing the likelihood of hybridization. However, hybridization of insect species and its consequences for agroecosystems have not received sufficient attention. Gene exchange between distinct and distant genetic pools can improve the survival and reproduction of insect pests, and threaten beneficial insects in disturbed agricultural environments. Hybridization may be the underlying explanation for the recurrent pest outbreaks and control failures in putative hybrid zones, as suspected for bollworm, corn borer, whiteflies, and stink bugs. Reliable predictions of the types of changes that can be expected in pest insect genomes and fitness, and of their impacts on the fate of species and populations remain elusive. Typical steps in pest management, such as insect identification, pest monitoring, and control are likely affected by gene flow and adaptive introgression mediated by hybridization, and we do not have ways to respond to or mitigate the problem. To address the adverse effects of farming intensification and global trade, we must ensure that current integrated pest management programs incorporate up‐to‐date monitoring and diagnostic tools. The rapid identification of hybrids, quantification of levels of introgression, and in‐depth knowledge of what genes have been transferred may help to explain and predict insect population outbreaks and control failures in the future. © 2019 Society of Chemical Industry     

Pharmocokinetic and pharmacodynamic evaluation of intravenous morphine in dogs

Morphine is considered the prototypical opiate analgesic. Despite the common use of morphine in dogs, ideal dosing strategies have not been formulated due to the difficulty in assessing its analgesic effects. The purpose of this study was to: 1) evaluate a noninvasive mechanical threshold device (von Frey device) to measure antinociceptive responses (pharmacodynamics) of opiates in dogs and 2) evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) of intravenous (IV) morphine in dogs. Six healthy Beagle dogs were used. The von Frey threshold (vFT) response was evaluated hourly for 8 hours in each dog to examine the effect of repeated testing (controls). PK and PD (vFT) measurements were then made following a 1 mg kg^–1 IV bolus of morphine sulfate. A two way blinded crossover consisted of an 8 hour IV constant rate infusion of saline or morphine with hourly PD measurements. The individual CRI was based on individual PK data and adjusted every 2 hours to attain targeted plasma concentrations of morphine of 10, 20, 30, and 40 ng mL^–1. Blood samples were taken hourly in all phases, except the controls. No significant (p > 0.05) intraindividual changes in vFT occurred in the controls over 8 hours. The morphine bolus produced increased vFT at 1, 2, 3, and 4 hours post injection (p < 0.05). The E_MAX and EC₅₀ following the IV bolus were 213 ± 104% (increase from baseline) and 13.9 ± 5.8 ng mL^–1, respectively. The CRI produced increased vFT at plasma concentrations >30 ng mL^–1, when compared to saline controls (p < 0.05). Targeted plasma concentrations were inconsistent at higher infusion rates, suggesting the PK of morphine may change during CRI. The actual mean ± SD CRI plasma concentrations (ng ml^–1) were 10.8 ± 3.0, 22.7 ± 7.4, 32.4 ± 13.9, 35.7 ± 16.9. Morphine dosing protocols should be re‐evaluated, as sufficient analgesia may not be obtained from published dosages. Intravenous boluses may be more predictable than CRI.     

Air Pollution Processing by Radiation Fogs

Several fog episodes occurred in California’s San Joaquin Valley during winter 2000/2001. Measurements revealed the fogs to generally be less than 50 m deep, but to contain high liquid water contents (frequently exceeding 200 mg/m³) and large droplets. The composition of the fog water was dominated by ammonium (median concentration?=?608 μN), nitrate (304 μN), and organic carbon (6.9 ppmC), with significant contributions also from nitrite (18 μN) and sulfate (56 μN). Principal organic species included formate (median concentration?=?32 μN), acetate (31 μN), and formaldehyde (21 μM). High concentrations of ammonia resulted in high fog pH values, ranging between 5.8 and 8.0 at the core measurement site. At this high pH aqueous phase oxidation of dissolved sulfur dioxide and reaction of S(IV) with formaldehyde to form hydroxymethanesulfonate are both important processes. The fogs are also effective at scavenging and removal of airborne particulate matter. Deposition velocities for key solutes in the fog are typically of the order of 1–2 cm/s, much higher than deposition velocities of precursor accumulation mode aerosol particles. Variations were observed in deposition velocities for individual constituents in the order NO₂ ^??>?fogwater?>?NH₄ ⁺?>?TOC ～ SO₄ ^2??>?NO₃ ^?. Nitrite, observed to be enriched in large fog drops, had a deposition velocity higher than the average fogwater deposition velocity, due to the increase in drop settling velocity with size. Species enriched in small fog drops (NH₄ ⁺, TOC, SO₄ ^2?, and NO₃ ^?) all had deposition velocities smaller than observed for fogwater. Typical boundary layer removal rates for major fog solute species were estimated to be approximately 0.5–1 μg m^?3 h^?1, indicating the important role regional fogs can play in reducing airborne pollutant concentrations.     

Corpus Luteum–Endometrium–Embryo Interactions in the Dairy Cow: Underlying Mechanisms and Clinical Relevance

Conception rates of dairy cows are currently declining at an estimated 1% every year. Approximately, 35% of embryos fail to prevent luteolysis during the first three weeks of gestation. Interactions between the corpus luteum, endometrium and embryo are critical to the successful establishment of pregnancy and inadequacies will result in the mortality of the embryo. For example, as little as a one day delay in the post-ovulatory rise of progesterone has serious consequences for embryo development and survival. Recently, we found that LH support, degree of vascularization and luteal cell steroidogenic capacity were not the major factors responsible for this luteal inadequacy, but are nevertheless essential for luteal development and function. Progesterone acting on its receptor in the endometrium stimulates the production of endometrial secretions on which the free-living embryo is dependent. However, their exact composition and effects of inadequate progesterone remains to be determined. The embryo is recognized through its secretion of interferon tau (IFNT), which suppresses luteolytic pulses of prostaglandin F_2α. In the cow, it is most likely that IFNT inhibits oxytocin receptor up-regulation directly and does not require the prior inhibition of oestrogen receptor α (ESR1). Unravelling the precise luteal-endometrium and embryo interactions is essential for us to understand pregnancy establishment and development of strategies to reverse the declining fertility of dairy cows.     

Determination of the optimal water temperature for the culture of juvenile dusky kob Argyrosomus japonicus Temminck and Schlegel 1843

The effects of temperature on growth, food-conversion ratio (FCR) and feeding intensity of juvenile dusky kob Argyrosomus japonicus (23.7±2.6 g fish⁻¹) were assessed over the temperature range 17.5–28.5 °C in a 42-day growth trial. Growth increased with increasing temperature up to an optimum after which it declined. Specific growth rates were 2.05% and 1.2% day⁻¹ for the fastest (25.3 °C) and the slowest (17.5 °C) treatments respectively. Food-conversion ratio peaked at a lower temperature than growth. Optimal (0.72 kg kg gain⁻¹) and least efficient (1.40 kg kg gain⁻¹) FCR were found at 21.7 and 17.5 °C respectively. Feeding intensity was linearly related to temperature within the range of 17.5–28.5 °C. These results corresponded to the thermal preference (25–26.4 °C) and natural temperature distribution (12–28 °C) of South African dusky kob. Determination of the temperature range that does not limit growth is a prerequisite to assess the relationship between growth and environmental variables such as light intensity, feeding regime and stocking density. Consequently, experiments to determine the effects of these environmental variables on growth and aquaculture potential of dusky kob should be conducted at 24–26 °C.     

Comparison of the Chemical Composition of Precipitation on the Western and Eastern Coasts of Korea

Precipitation samples were collected at two coastal sites on the Korean Peninsula, Kangwha on the western coast and Yangyang on the eastern coast, from September 1991 to February 1997. The samples were analyzed for concentrations of major ions, in addition to pH and electrical conductivity. The annual volume-weighted mean pH values were 4.89 and 5.05 at Kangwha and Yangyang, respectively. The pH was generally lower at Kangwha than that at Yangyang, especially during the winter, because of reduced neutralizing inputs and greater acid inputs in winter. Dominant ions were different with NH₄ ⁺ and SO₄ ^2- most important at Kangwha and Na⁺ and Cl^- at Yangyang. Neglecting sea salt components, nss-SO₄ ^2- and NO₃ ^- were important anions and nss-Ca²⁺ and NH₄ ⁺ were important cations at both sites. Concentrations of these ions were 1.2–1.6 times higher at Kangwha than at Yangyang. Annual mean concentrations of these ions varied little during the study, while larger seasonal variations were observed. Annual mean nss-SO₄ ^2-/NO₃ ^- ratios at Kangwha and Yangyang were 2.8 and 2.6. The 5 yr annual mean values of nss-SO₄ ^2-/NO₃ ^- showed no trend at Kangwha but a decreasing tendency at Yangyang. The decreasing trend is similar to the decreasing trend in emissions of SO₂/NO_x in South Korea. Regional differences in chemical composition between Kangwha and Yangyang appear to be associated with long-range transport of acidic gases and alkaline dust originated from other regions.     

Spirometra erinacei / S. erinaceieuropaei in a feral cat in Manawatu with chronic intermittent diarrhoea

CASE HISTORY: A feral cat captured in the Manawatu region of New Zealand was treated for worms and fleas, and kept confined in a metabolic cage. It showed good appetite and weight gain but had intermittent watery, yellow diarrhoea.

CLINICAL FINDINGS: Clinical examination under sedation was unremarkable and routine blood tests showed no significant abnormalities. The cat was negative for feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV). Different canned cat foods did not alter the course of the diarrhoea, and the cat was euthanised 6 months after capture. At necropsy, two sections of adult Spirometra tapeworms were found in the jejunum and typical Spirometra eggs were found in colonic contents. Molecular identification of the parasite was undertaken, using the cytochrome- c oxidase subunit-1 gene (cox1) sequence.

DIAGNOSIS: Chronic intermittent diarrhoea associated with Spirometra erinacei / S. erinaceieuropaei infection.

CLINICAL RELEVANCE: Spirometra has not been reported in New Zealand before but has been associated with gastrointestinal disease in cats in other parts of the world. It requires speciestargeted treatment to be eliminated effectively, and is zoonotic. Diagnosis could be diffi cult for clinicians who are not familiar with the parasite and its life cycle.