Response of an aphid parasitoid, Aphelinus asychis to its host, plant, host-plant complex, and to malathion

Aphelinus asychis (Walker) can be valuable as a biocontrol agent of the aphid, Schizaphis graminum (Rondani), a major pest on grain crops in the United States. This study reports the wind tunnel, and olfactometric responses of this parasitoid to the host (aphid), plant (sorghum), and host-plant complex (aphid-infested sorghum). In addition, the parasitoids' response to malathion-treated plants is also presented. The goal of the present study was to test the hypothesis that volatiles associated with the host attract natural enemies, as reported in cases of many hymenopterous parasitoids, and also to learn about the effects of insecticides on these parasitoids. In wind tunnel studies, these parasitoids moved upwind in the direction of the host-infested plant. There was no direct flight observed, however, these parasitoids were observed to hop and jump, and sometimes walk to their host. In the olfactometer experiments, we found that A. asychis is attracted to host-plant complex. The parasitoids' response to malathion in the olfactometer suggested that a malathion formulation when applied to plants can lure these beneficials, thus providing new insight into the ongoing task of integrating chemical and biological control of insect pests.     

Responses of brambles,Rubus vestitus,to herbivory

We investigated the effect of fertilisation and multiple episodes of simulated herbivory on the prickliness of bramble, Rubus vestitus. The prickliness of fertilised, uncut plants was significantly greater than that of plants in all other treatments. Our results indicate that prickle production is constrained by resource availability, with brambles allocating resources to growth under intense herbivory. Isozyme electrophoresis of plants collected from Wytham Woods, Oxford, UK, failed to detect any variation, suggesting that observed variation in prickliness may be primarily the result of phenotypic plasticity. In our experiments, however, we observed significant variation in prickliness among putative genotypes.     

From Bretonneau to therapeutic antibodies,from specificity to specific remedies,Saint-Cyr-Sur-Loire,France, November 19, 2012

Held on November 19, 2012 in Saint-Cyr-sur-Loire, France, the symposium “From Bretonneau to therapeutic antibodies, from specificity to specific remedies” focused on the historical development of antibodies as therapeutics, with an emphasis on the seminal work of the French physician Pierre-Fidèle Bretonneau (1778–1862). The morning session was devoted to discussion of the evolution of the concept of specificity in medicine, which started with an epistemological definition. The contributions of Bretonneau to the emergence of the concept of specificity, notably with his studies on diphtheria, and the subsequent development of antidiphtheric serotherapy in Europe during the period 1894–1898 were then presented in detail. The afternoon session began with a presentation on the role of French physiologists during the years 1860–1890 in establishing the basic concepts of specific immunity and the principles of serotherapy. The history of antivenom serotherapy, particularly its discovery by Césaire Phisalix, and the development of antilymphocyte globulins as successful transplantation drugs were then discussed. The symposium ended with the inauguration of a stele representing Bretonneau, who lived in Saint-Cyr-sur-Loire and died 150 y ago.     

Protein tyrosine phosphatases: from genes, to function, to disease

The protein tyrosine phosphatase (PTP) superfamily of enzymes functions in a coordinated manner with protein tyrosine kinases to control signalling pathways that underlie a broad spectrum of fundamental physiological processes. In this review, I describe recent breakthroughs in our understanding of the role of the PTPs in the regulation of signal transduction and the aetiology of human disease.     

Intermediate binding of phycocyanobilin to the lyase, CpeS1, and transfer to apoprotein

The phycobilin: Cysteine-84-phycobiliprotein lyase, CpeS1, catalyzes phycocyanobilin (PCB) and phycoerythrobilin attachment to nearly all cysteine-84 (consensus sequence) binding sites of phycoerythrin, phycoerythrocyanin, phycocyanin and allophycocyanin (Zhao et al. (2007) Proc Natl Acad Sci 104:14300–14305). We now show that CpeS1 can bind PCB, as assayed by Ni²⁺ chelating affinity chromatography. Binding is rapid, and the chromophore is bound in an extended conformation similar to that in phycobiliproteins but only poorly fluorescent. Upon addition of apo-biliproteins, the chromophore is transferred to the latter much slower (∼1 h), indicating that chromophorylated CpeS1 is an intermediate in the enzymatic reaction. In addition, imidazole is bound to PCB, as shown by mass spectroscopy of tryptic digests of the intermediate CpeS1–PCB complex.     

Effects of Obstruction to Respiration in Infants,with Particular Reference to Mattresses,Pillows, and their Coverings

A comparison was made of pillows of various designs and their effects on the flow of air through the respiratory tract of six children who had been found dead in their cots. The effects of alterations in posture and of soaking the pillow with milk were also studied.There was a wide variation in the obstruction to air flow in pillows of different design. A firm pillow which allows air and fluid to pass through it is best, and is probably superior to a mattress covered with a mackintosh and a sheet.External obstruction to respiration could be a contributory factor in some cases of cot death.     

Strain-dependent, route of challenge-dependent, murine susceptibility to toxoplasmosis

The response to an intraperitoneal (i.p.) parasite challenge was compared with that caused by an oral challenge, in five different strains of mice. The results are consistent with the hypothesis that murine susceptibility to toxoplasmosis is route of challenge-dependent as well as strain-dependent. The phenomenon occurs in both sexes and appears to be a recessive trait. The finding that the susceptibility of C57BL/6j mice to oral or i.p. challenge is almost the reverse of that of LACA mice, and that BALB/c mice are resistant to challenge by either route, offers an excellent laboratory model for studies on susceptibility to toxoplasmosis.     

Adaptation of fungi,including yeasts,to cold environments

A wide range of cold environments exist, with an equally broad variety of fungi and yeasts that have adapted to such environments. These adaptations, which affect membranes, enzymes and other cellular components, such as radical scavenging molecules, display a great potential for exploitation in biotechnology. Alterations have been detected in membrane lipids, with an increase in fatty acid unsaturated bonds that enhance their fluidity. We report new data on the different phospholipid composition in membrane lipids in the same fungal species from both Antarctic and temperate regions. The decrease in temperature causes intracellular oxidative stress by inducing the generation of reactive oxygen species. We report the results of the first analysis of the non-enzymatic antioxidant response and phenolic compound production by an Antarctic strain of Geomyces pannorum. A survey on yeasts from the cryosphere is reported with a focus on their adaptation to a cold environment. Some studies have shown that the number of macrofungi in glacier forefronts rises as deglaciation increases. The survival success of many plants in such areas may be attributed to their mycorrhizal associations. We highlighted the macrofungal biodiversity of some Italian alpine habitats, in which we Inocybe microfastigiata, Laccaria montana and Lactarius salicis-herbaceae were recorded for the first time in Lombardy (Italy).     

Stream ecosystem response to, and recovery from, experimental exposure to selenium

The effects of selenium on streamecosystems were studied in outdoor,experimental stream mesocosms during a dosingperiod in which sodium selenite was added atnominal concentrations of 30 µg/L,10 µg/L, and 2.5 µg/L. The durationof the high, medium, and low treatments were573 d, 972 d, and 311 d, respectively. Apost-dosing period of three years (hightreatment) and two years (medium, lowtreatments) also was studied. Seleniumconcentrations in water, sediment, plants, andmacroinvertebrates were measured throughoutthe dosing and recovery periods. Fatheadminnows and bluegill sunfish were periodicallyheld in the streams to measure seleniumaccumulation and its effects on fish survivaland reproduction. Quantitative samples ofmacroinvertebrates were collected to assessselenium effects on macroinvertebratecommunities.Mean selenium concentration inwater was quite close to the nominalconcentration. Selenium accumulated in thesediment in all three treated streams, but notin the control streams. Sediment seleniumdecreased slowly after dosing ceased, but wasstill significantly higher than in controlstreams three years (high treatment) and twoyears (medium treatment) later.Macrophytetissue selenium concentrations weresignificantly greater in all three treatmentsthan those in the control streams duringdosing. Macrophyte selenium bioaccumulationfactors (BAFs) ranged from about 300 to 1900. Tissue selenium decreased rapidly in all threetreatments after dosing ended.During dosing,selenium concentrations in animals from allthree treatments were significantly higherthan in those from control streams. The BAFsfor macroinvertebrates ranged from 1100 to2000. Isopods accumulated more, and amphipodsless, selenium than other invertebrates. Therewere no significant effects of selenium onmacroinvertebrate abundance, richness ordiversity. Several macroinvertebrates werenot affected by exposure to selenium, butisopod and Tubifex populations weredramatically reduced in the high and mediumtreatments. After dosing, mean seleniumconcentration in macroinvertebrates decreasedslowly.Bluegill sunfish accumulated seleniumduring dosing and after selenium additionsceased. Tissue selenium was highest in theliver, followed by the gonads, skeletalmuscle, and whole body. Tissue seleniumconcentrations one (high, medium) and two(high) years after dosing were lower thanduring dosing, but whole body, skeletal muscleand liver concentrations were high enough tobe considered potentially toxic.Recovery ofselenium contaminated streams includes bothreduction of tissue selenium concentration tonon-toxic levels in fish and their foodorganisms and recovery of populations of taxadeleteriously affected by selenium exposure. Our results suggest that when selenium iseliminated from the water in streams, seleniumconcentrations in sediment, plants,macroinvertebrates, and fishes will decreaseto levels that approach concentrationsconsidered to be non-toxic to fish andwildlife and that affected populations willrecover within several years. Based onselenium accumulation in the food chain andthe presence of real, but not statisticallysignificant, effects on fish mortality andreproduction in the low treatment streams, wesupport a selenium water quality criterion forthe protection of fishes and sensitiveinvertebrates of 2 µg/L or less.