A method for the extraction ofSitona [Col.: Curculionidae] eggs from soil and occurrence of a mymarid [Hym.: Chalcidoidea] in the mediterranean region

A simple method of extracting the eggs ofSitona spp. from the soil is described. From 1973 to 1975 it was used in Spain, France, Italy and Greece to collect in good condition the eggs ofSitona humeralis Stephens, a weevil which has recently become a major pest in Australia. A mymarid parasitoid provisionally identified asPatasson lameerei Debauche emerged from these eggs apparently unaffected by the extraction method.     

Biology of Ixodes (Pholeoixodes) hexagonus under laboratory conditions. Part I. Immature stages

A rearing method for Ixodes (Pholeoixodes) hexagonus, the hedgehog tick, was established which enabled the life cycle of immature stages to be studied under laboratory conditions. Larvae were fed on Swiss mice and nymphs on the cars of New Zealand rabbits. The feeding time of the larvae and nymphs on both hosts was 4–17 days. Larvae moulted to nymphs 15–21 days after detachment from mice. The premoulting period was 13–26 days for newly emerged males and 15–27 days for females. Engorged nymphs which developed into males weighed less (5.64±0.91 mg) than those that developed into females (6.019±88mg). The sex ratio (male: female) under laboratory conditions was 1:1.13.     

The effect of yeast extract supplementation on the production of lactic acid from whey permeate byLactobacillus helueticus

Summary Batch and continuous two-stage cultures have been conducted in order to determine the effect of yeast extract (YE) on the homolactic fermentation of whey permeate byLactobacillus helveticus. Supplementation with YE had a significant effet on lactic acid concentration, volumetric productivity, and substrate conversion, but not on lactic acid yield. Volumetric productivity in the first stage increased from 2 to 9 g l^–1 per hour by increasing the YE concentration from 1.5 to 25 g l^–1 At the same time conversion improved from 22% to 93% at a dilution rate of 0.2 h^–1. The second stage demonstrated the effect of YE at a lower dilution rate (0.14 h^–1. A high system conversion (97%) and a high final lactic acid concentration (40 g l^–1) were achieved with 10 g l^–1 YE.     

Borrelia burgdorferi in ticks of the Canton Tessin (Switzerland)

In the northern Alps it is hard to find an Ixodes ricinus population which does not harbour Borrelia burgdorferi. The infection rates range from 5 to 34% for adults and nymphs to 3.1% for larvae. This study shows that the infection rates on the southern side of the Alps are similar, at 25% for adults, 36.2% for nymphs and 3.2% for larvae. With respect to tick species other than I. ricinus, we did not succeed in finding any spirochetes in Dermacentor marginatus, Haemaphysalis punctata, Ixodes hexagonus, Rhipicephalus sanguineus.     

Proportional dry-mass content as an underlying trait for the variation in relative growth rate among 22 Eurasian populations of Dactylis glomerata s.l.

1. Relative growth rate (RGR), proportional dry-mass content of leaf and stem tissues, and biomass-allocation pattern were assessed under controlled conditions for 22 populations of Dactylis glomerata s.l. from contrasting latitudes and altitudes in Europe, Israel and Kazakstan. Furthermore, width and thickness of leaves were measured in garden-grown mature plants.
2. All these parameters varied significantly among the populations. RGR correlated negatively with dry-mass content of leaves and stems, but not with biomass-allocation parameters, leaf thickness or leaf width. We argue that the close association of RGR with variation in dry-mass content among species and genetically distinct populations is a result of the larger volume of tissue, and correspondingly larger leaf area and longer root system, that a plant with a low tissue density can build per unit dry mass.
3. Leaf tissue dry-mass content decreased and RGR increased with increasing latitude and elevation of the originating site, indicating that a high growth rate may be an advantage in habitats with a short growing season. This contrasts with earlier findings of a negative correlation between inherent RGR and altitude.     

Reappraising the potential of biological control against the weedCarthamus lanatus

Carthamus lanatus L. (Compositae, saffron thistle) is a major weed of worldwide distribution that originated in southern Europe. Surveys, rearings, tests of specificity, and in-depth field studies undertaken between 1990 and 1995 have considerably improved our understanding of the complex of natural enemies associated withC. lanatus in its native range. The root-feeding fly,Botanophila turcica Hennig (Dipt.: Anthomyiidae) is herewith recorded for the first time fromC. lanatus; the rosette rust fungus,Puccinia sommieriana Saccardo (Basid.: Pucciniaceae) is reported for the first time fromC. lanatus in Greece; the flowerhead fly,Urophora mauritanica Macquart (Dipt.: Tephritidae) is shown to concentrate its attacks onC. lanatus in the field in presence of the closely relatedCarthamus tinctorius L. (cultivated safflower). According to site and year the direct mortality caused by each of these three organisms to populations ofC. lanatus fluctuated between 10 and 50%. In addition, each of them had a whole range of indirect effects of some importance onC. lanatus populations, all of which were also cumulative. Strong phenological (in the case ofB. turcica), and practical evidence (field records, plus results of host specificity tests) are presented, and discussed which document the fact that the three phytophagous species may be considered as specifically attackingC. lanatus, but without damaging field crops of its close relative,C. tinctorius. Contrary to traditional belief, biological control may therefore be considered a promising, safe approach for reducingC. lanatus populations.

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Importantes découvertes récentes permettant de ré-évaluer le potentiel de la lutte biologique contreCarthamus lanatus L.

Résumé Prospections, dissections, élevages au laboratoire et études détaillées en sites permanents, effectués de 1990 à 1995 en Europe méridionale dans toute la région d’origine deCarthamus lanatus L. (Compositae), une mauvaise herbe de grande importance économique à travers le monde, ont permis d’approfondir notablement la connaissance de ses ennemis naturels. La mouche des rosettes (Botanophila turcica Hennig; Dipt. : Anthomyiidae) a ainsi été détectée pour la première fois surC. lanatus. La rouillePuccinia sommieriana Saccardo (Basid. : Pucciniaceae) est signalée pour la première fois de Grèce sur cette adventice. Enfin, il est montré que la mouche des capitulesUrophora mauritanica Macquart (Dipt. : Anthomyiidae) concentre ses attaques en champ surC. lanatus. Chacun de ces trois organismes a engendré sur les populations de la mauvaise herbe une mortalité directe fluctuant entre 10 et 50 % suivant les sites et les années, induisant en outre des effets indirects de moindre importance, certes, mais apparemment tous cumulatifs. Ces trois espèces de phytophages peuvent être considérées comme pratiquement inféodées àC. lanatus. Ils ne présentent donc aucun danger pour les cultures de carthame cultivé (C. tinctorius L.), pourtant très proche parent de l’adventice, pour des raisons tenant à leur incompatibilité phénologique (dans le cas deB. turcica notamment). L’absence de tout relevé signalant leur présence surC. tinctorius dans une aire où les deux espèces végétales cohabitent depuis des décennies, et les résultats des premiers tests de spécificité confortent en outre cette hypothèse. Contrairement aux appréhensions formulées jusqu’ici, la lutte biologique constitue donc une solution réellement prometteuse pour l’avenir en vue de réduire les populations nuisibles de cette mauvaise herbe.

     

Identification of Gln726 in nidogen as the amine acceptor in transglutaminase-catalyzed cross-linking of laminin-nidogen complexes.

The laminin-nidogen complex, the most abundant noncollagenous component of basement membranes, was recently shown to be a specific substrate for tissue transglutaminase (Aeschlimann, D., and Paulsson, M. (1991) J. Biol. Chem. 266, 15308-15317). Saturation experiments to determine the number of amine acceptor site(s) indicated a single reactive Gln residue in nidogen and none in laminin. Murine nidogen was labeled with [3H]putrescine in the tissue transglutaminase-catalyzed reaction, and two major radioactively labeled fragments, T70 and T40, were isolated after limited trypsin digestion. NH2-terminal sequencing showed that T40 is contained in T70 and corresponds to the rodlike structure of nidogen, made up of epidermal growth factor-like repeats. Three radioactively labeled peptides, obtained by extensive trypsin digestion of reduced and alkylated T40, were sequenced. In all a single residue, Gln726, was found to contain label. Sequencing of additional peptides, obtained after further treatment of the largest radioactively labeled peptide with endoproteinase Asp-N, gave the same result. Gln726 is located in an exposed loop between the second and the third EGF-like repeat in nidogen. This site is also conserved in the human sequence.     

Gluten T cell epitope targeting by TG3 and TG6; implications for dermatitis herpetiformis and gluten ataxia

Transglutaminase 2 (TG2) is well characterized as the main autoantigen of celiac disease. The ability of TG2 to deamidate and crosslink gluten peptides is essential for the gluten-dependent production of TG2 specific autoantibodies. In patients with primarily extraintestinal manifestation of gluten sensitivity the repertoire of autoantibodies may be different. In dermatitis herpetiformis (DH), TG3 appears to be the target autoantigen whereas in gluten ataxia (GA) autoantibodies reactive with TG6 are present. A functional role for TG3 and TG6 in these diseases has yet to be described. It is also not known whether these enzymes can use gluten peptides implicated in the pathology as substrates. We here report that similar to TG2, TG3 and TG6 can specifically deamidate gluten T cell epitopes. However, the fine specificities of the enzymes were found to differ. TG2 can form covalent complexes with gluten by iso-peptide and thioester bonds. We found that both TG3 and TG6 were able to complex with gluten peptides through thioester linkage although less efficiently than TG2, whereas TG6 but not TG3 was able to form iso-peptide linked complexes. Our findings lend credence to the notion that TG3 and TG6 are involved in the gluten-induced autoimmune responses of DH and GA.