Parasitism of non-target lepidoptera by mass released Trichogramma brassicae and its implication for the larval parasitoid Lydella thompsoni

The release of high numbers of the eggparasitoid Trichogramma brassicae Bezd.(Hym. Trichogrammatidae) to control theEuropean corn borer (ECB), Ostrinianubilalis Hb. (Lep.: Crambidae) in maize hasraised concerns about potential negativeeffects on native natural enemies. The nativelarval parasitoid Lydella thompsoniHerting (Dipt.: Tachinidae) is the mostfrequent and important ECB parasitoid insouthern Switzerland and can achieve highparasitism rates. Its first generation emergestoo early to find ECB larvae and must rely onalternative hosts living in natural habitatsclose to maize fields. Inundative releases ofT. brassicae coincide with theoviposition period of the alternative hosts ofthe tachinid. T. brassicae moving out ofrelease fields may attack and diminish thepopulation of these hosts, creating abottleneck situation for L. thompsoni inthe subsequent spring. Laboratory hostspecificity tests showed that the tachinid'stwo most abundant spring hosts Archanarageminipuncta Haworth (1809) (Lep.: Noctuidae)and Chilo phragmitellus Hübner (1805)(Lep.: Crambidae) are successfully parasitisedby T. brassicae females in no-choicesituations. Our extensive field surveys,however, showed that the two tested springhosts escape parasitism since their eggs arewell hidden or not attractive. Negativeeffects of inundative releases of T.brassicae on the native tachinid fly L. thompsoni, such as population densityreduction, displacement, or local extinction,are very unlikely.     

Reproductive trade-offs in a specialized plant/pollinator system involving Asplundia uncinata Harling (Cyclanthaceae) and a derelomine flower weevil (Coleoptera: Curculionidae)

The reproductive interactions of a specialized plant/pollinator system involving Asplundia uncinata Harling (Cyclanthaceae) and a derelomine flower weevil (Coleoptera: Curculionidae: Derelomini) were studied at La Selva, Costa Rica. The inflorescences of A. uncinata exhibit a suite of cantharophilous characters including a precisely synchronized anthesis, protogyny, thermogenesis, olfactory attraction of visitors via modified staminodes, and narrow interfloral entrances. The weevil pollinators use the inflorescences for feeding, mating, and oviposition. The larvae are detritivorous and develop either in the detaching staminate flowers or, at a more favorable rate, in the rotting infructescences. The rate of infructescence abortion was high and caused by low levels of pollination. Manual pollination treatments yielded significantly higher seed counts than obtained under natural conditions, and furthermore demonstrated the inflorescences' ability to reproduce via geitonogamy. In the longer term, the reproductive benefits of maintaining low levels of pollination may shift away from the weevils and towards the plants via an increase in the size of the pollinator population.     

Allogrooming Behavior and Grooming Site Preferences in Captive Bonobos (Pan paniscus): Association with Female Dominance

I tested the utility of Seyfarth's (1977) model of rank-related attractiveness to explain the distribution of allogrooming behavior among captive bonobos (Pan paniscus). Adult female bonobos generally have high social status and may be dominant over males. As predicted by the model, I found that high-ranking adult females received most allogrooming within each of the four investigated groups. Among adult female-adult female dyads, however, allogrooming was not clearly associated with dominance rank. Contradictory to predictions of the model, the highest-ranking females were responsible for most displacements over allogrooming, and grooming competition is positively correlated with dominance rank. In the second part of this study, I investigated the social significance of allogrooming body site preferences. Bonobos direct significantly most allogrooming to the face of conspecifics, and high- and low-ranking individuals, as well as males and females, differ significantly in their preferences for certain allogrooming sites. Subordinates and males tended to avoid facial grooming and preferred the back and anogenital region, while high-ranking individuals and females directed most allogrooming to the face and head of grooming partners. Data from this study support the hypothesis that high-ranking females are the most attractive grooming partners within a female-centered bonobo society. Many other aspects of allogrooming behavior, however, are not consistent with the model of rank-related attractiveness.     

Studies on the mechanism of NADPH oxidation by the granule fraction isolated from human resting polymorphonuclear blood cells.

Various factor affecting NADPH-oxidation by resting human leucocyte granules (LG) at acid pH, have been investigated. It was found that: 1) oxidation of NADPH by LG was increasingly inhibited by increased cyanide concentrations in the medium and was abolished by 4 mM cyanide. 2) with or without cyanide in the incubation medium, LG omitted, Mn++ in the presence of NADPH induced superoxide anion (O- WITH 2) production, as evidenced by oxygen consumption and H2O2 production, which were abolished (in the absence of cyanide) by cytochrome C (a potent O- with 2 scavenger). 3) Both NADPH oxidation in the presence of 2 mM cyanide (cyanide-resistant) and in its absence (cyanide-sensitive) by LG occurred only in the presence of Mn++, and both were inhibited by superoxide dismutase. 4) Cyanide-resistant NADPH oxidation by LG generated H2O2, was inhibited by H2O2 and was not modified by "active" catalase. The ratio of cyanide-resistant NADPH oxidation/O2 uptake was 1 up to 1.25 mM NADPH, and increased above this concentration. 5) Cyanide-sensitive NADPH oxidation was inhibited by catalase and increased upon addition of H2O2. The ratio of cyanide-sensitive NADPH oxidation/O2 uptake was 2. It was concluded that after initiation by O - with 2, produced independently of LG, two sequential types of LG dependent NADPH oxidations occur. First, an O - with 2-dependent protein mediated NADPH oxidation (cyanide-resistant) which generates H2O2 and O - with 2 occurs. Second, NADPH peroxidation (cyanide-sensitive) which utilizes H2O2 takes place.     

Longitudinal analysis of taurine induced effects on the tear proteome of contact lens wearers and dry eye patients using a RP-RP-Capillary-HPLC-MALDI TOF/TOF MS approach

Tear proteomic studies revealed distinct similarities between contact lens wearers and dry eye patients. AMO Complete® multipurpose contact lens cleaning solutions containing taurine seem to have a beneficial effect regarding contact lens induced dry eye. To illuminate the effect of taurine on the tear proteome of contact lens wearers and sicca patients we developed a gel-based RP-RP capillary HPLC–MALDI TOF/TOF MS strategy. Two contact lens wearer groups, one using eye drops containing 0.05% taurine; the other for control physiological NaCl solution were monitored. Also, a third group of sicca patients using taurine solution was studied (N = 4 individuals/group). Tear pools of each group at six time points over 5 weeks were analyzed. In summary 267 tear proteins were identified. We found a protein subset showing a linear taurine response with R² values ≥ 0.5. Taurine effects were detected predominantly in the contact lens group demonstrated by distinct level decreases. Most protein candidates were related to inflammation. Since levels of these proteins differentiate from those of a healthy non-contact lens wearer reference they are supposed to be involved in contact lens induced dry eye and should be focused on in further studies.     

Hfq Influences Multiple Transport Systems and Virulence in the Plant Pathogen Agrobacterium tumefaciens

The Hfq protein mediates gene regulation by small RNAs (sRNAs) in about 50% of all bacteria. Depending on the species, phenotypic defects of an hfq mutant range from mild to severe. Here, we document that the purified Hfq protein of the plant pathogen and natural genetic engineer Agrobacterium tumefaciens binds to the previously described sRNA AbcR1 and its target mRNA atu2422, which codes for the substrate binding protein of an ABC transporter taking up proline and γ-aminobutyric acid (GABA). Several other ABC transporter components were overproduced in an hfq mutant compared to their levels in the parental strain, suggesting that Hfq plays a major role in controlling the uptake systems and metabolic versatility of A. tumefaciens. The hfq mutant showed delayed growth, altered cell morphology, and reduced motility. Although the DNA-transferring type IV secretion system was produced, tumor formation by the mutant strain was attenuated, demonstrating an important contribution of Hfq to plant transformation by A. tumefaciens.     

Photodamage to the cutaneous sensory nerves: role in photoaging and carcinogenesis of the skin?

Chronic exposure to ultraviolet radiation (UVR) plays a significant role in aging and carcinogenesis of the skin. Sensory nerve fibers densely innervate all layers of the skin and get in close anatomical as well as functional contact with cellular components of the epidermis and dermis. In this review, we address the impact of acute and chronic UVR exposure on the cutaneous sensory nervous system and its mediators. We suggest that skin cell-derived nerve growth factor (NGF) and skin nerve-derived neuropeptides such as substance P (SP) and calcitonin gene-related peptide (CGRP) may play a central role in intrinsic aging as well as extrinsic (photo-) aging of the skin. In addition, we discuss the possible role of these mediators in photocarcinogenesis.     

Site-directed mutagenesis of the charged residues near the carboxy terminus of the colicin E1 ion channel

Colicin E1 was altered by oligonucleotide-directed mutagenesis at the site of three charged residues on the COOH side of the 35-residue hydrophobic segment in the channel-forming domain. Asp-509 is one of five conserved acidic residues in the channel domain of colicins A, B, E1, Ia, and Ib and is the first charged residue following the hydrophobic segment, followed by the basic residues Lys-510 and Lys-512. Asp-509 and Lys-512 were changed to amber and ochre stop codons, respectively, while Lys-510 was mutated to a Met codon. Proteins truncated after residue 508 or 511, and missing the last 14 or 11 residues, were obtained from a nonsuppressing cell strain harboring the mutant plasmid while full-length colicin molecules with single residue changes at Asp-509 to Leu, Ser, and Gln, and Lys-512 to Tyr, were obtained by using appropriate suppressor strains. The truncated colicins displayed (i) a low cytotoxicity, approximately 1% of intact wild-type colicin, (ii) 10-fold less in vitro channel activity with liposomes, and (iii) reduced labeling of the colicin in liposomes by a phospholipid photoaffinity probe, showing that one or more of the residues following Asn-511 is necessary for both in vivo and in vitro activity and insertion into the bilayer. (iv) The truncated mutants also displayed an altered conformation at pH 6 that allowed greater binding and activity with liposomes at this pH relative to wild type. The cytotoxicity of single residue substitutions at Asp-509 showed a range of cytotoxicities, wild type greater than Ser-509 greater than Gln-509 greater than Leu-509, although none of these changes greatly affected the in vitro channel activity or pH dependence.(ABSTRACT TRUNCATED AT 250 WORDS)