A comparative ecological investigation of two related mayfly nymphs

Zusammenfassung Heptagenia sulphurea wird auf Steinen, H. fuscogrisea in der Vegetation von Fließgewässern gefunden (Fig. 2).In Experimenten wählte H. sulphurea Steine und groben Kies. H. fuscogrisea wählte Batrachium als Substrat, nur ein geringer Anteil der Larven fand sich auf Callitriche (Fig. 3).Die Zeit, die zwischen Loslassen und erneutem Anhaften auf dem Substrat im strömenden Milieu verstreicht, war unterschiedlich bei den zwei Spezies. Die auf Steinen lebende Art reagierte schneller als die aus der Vegetation. H. sulphurea verhielt sich, wenn sie von der Strömung ergriffen worden war, ziemlich passiv, doch trug die turbulente Strömung das Tier dem Substrat zu, so hatte es gewöhnlich sicheren Halt.Im Strömungsaquarium bevorzugt H. sulphurea die strömungsexponierten Bereiche, aber viele waren auch im ruhigen Wasser (Fig. 5).Wurde H. fuscogrisea von der Strömung ergriffen, so führte sie Schwimmbewegungen aus. Erreicht sie eine Haltmöglichkeit an strömungsexponiertem Platz, so wird sie oft weitergetragen. Die Tiere lassen sie meist in ruhigem Wasser nieder.Im Strömungsaquarium bevorzugt H. fuscogrisea überwiegend die Regionen ruhigen Wassers (Fig. 5).Die Zeit zwischen Loslassen und Festsetzen war deutlich durch die Temperatur beeinflußt (Fig. 6).Der dichte Haarbesatz an der hinteren Kante der Femur von H. sulphurea wird als Anpassung an das Leben in der Strömung angesehen, weil er die Wirbelbildung herabsetzen kann. Der Haarbesatz entlang der Tibia bei H. fuscogrisea wird als Anpassung zum Schwimmen angesehen, zu dem these Spezies befähigt ist, wenn sie von der Strömung ergriffen wird (Fig. 8).Die Spezies von Steinen ist etwas mehr abgeflacht als die aus der Vegetation (Fig. 7).     

Behaviour and dispersal in adult Taeniopteryx nebulosa (Linnaeus, 1758) and Perlodes microcephalus (Pictet, 1833) (Plecoptera) in Denmark

Adult Taeniopteryx nebulosa (Linnaeus, 1758 Linnaeus, C. (1758), Systema Naturae (10th ed.), Tom 1, Holmiae. [Google Scholar]) and Perlodes microcephalus (Pictet, 1833 Pictet, J., (1833), ‘Memoire sur la Metamorphoses des Perles’, Annales des Sciences Naturelles, XXVII, 44–55. [Google Scholar]) emerge late winter to early spring in Danish streams. Based on 13 years of study, we have provided new data and discussed little-known aspects of biology of these two species. Taeniopteryx nebulosa male deposits a spermatophore on the female gonopore. Both species are poor fliers and seek high posts for take-off, where they thermoregulate by basking in a pre-flight sun posture for heating flight muscles. Oviposition flight is erratic and short. The females skim back to land. Taeniopteryx nebulosa eggs drift a long distance as single eggs before adhering to vegetation. Perlodes microcephalus eggs drift a short distance as intact eggpackets before they fasten and disintegrate on the bottom. Perlodes microcephalus females select oviposition sites on or close to upstream a riffle. This is critical in ensuring that eggs fasten on stable gravel and stone bottoms. The fast recolonisation of P. microcephalus in Danish streams following restoration measures indicates efficient dispersal ability despite poor flight performance. Adults of both species adhere to clothes, feather and fur. Taeniopteryx nebulosa tarsomeres have many hooked setae, P. microcephalus tarsomeres have some hooked setae and a dense cover of microtrichia. They may disperse by hitchhiking on birds and mammals.     

A cell-penetrating peptide from a novel pVII-pIX phage-displayed random peptide library

A novel random peptide library was constructed using a phage-display format on the coat proteins pVII and pIX of filamentous bacteriophage. Panning against B-lymphocyte WI–L2 cells yielded one unique peptide-phage, denoted CHL8, that specifically bound to and penetrated the cells. Studies of each peptide derived from CHL8, denoted pep7 and pep9, established that only pep7 mediated the observed activity and only as a homodimer. Peptide libraries displayed on pVII–pIX should serve as a novel source of bioactive ligands for a variety of applications.     

Phytotoxicity of Sodium Fluoride and Uptake of Fluoride in Willow Trees

The willow tree (Salix viminalis) toxicity test and a cress seed germination test (Lepidium sativum) were used to determine uptake of F and phytotoxicity of NaF. Concentrations in hydroponic solutions were 0–1000 mg F/L and 0–400 mg F/L in the preliminary and definitive test. A third test was done with soils collected from a fluoride-contaminated site at Fredericia, Denmark. The EC₁₀, EC₂₀ and EC₅₀-values for inhibition of transpiration were determined to 38.0, 59.6 and 128.7 mg F/L, respectively. The toxicity test with soil showed strong inhibition for the sample with the highest fluoride concentration (405 mg free F per kg soil, 75 mg F per L soil solution). The seed germination and root elongation test with cress gave EC₁₀, EC₂₀ and EC₅₀-values of 61.4, 105.0 and 262.8 mg F/L, respectively. At low external concentrations, fluoride was taken up more slowly than water and at high external concentrations at the same velocity. This indicates that an efflux pump becomes overloaded at concentrations above 210 mg F/L. Uptake kinetics were simulated with a non-linear mathematical model, and the Michaelis-Menten parameters were determined to half-saturation constant K_M near 2 g F/L and maximum enzymatic removal rate v_max at 9 g/(kg d).     

T cell-lymphoma in the eyelid of a 9-year-old English Setter

Background

Eyelid tumours are frequently found in dogs, most of these being benign. In case of an ulcerating eyelid tumour, malignancy must be considered. We report a unique case of a low-grade peripheral T-cell lymphoma in the eyelid of a 9-year-old English Setter.

Case presentation

A 9-year-old Setter presented with a 6-month history of an eyelid ulcer. A malignant eyelid neoplasm was suspected, and the lesion was surgically excised. No other treatment was applied, and 19 months after excision the dog was still well. Histopathology revealed a diffuse lymphocytic infiltrate in the eyelid skin. Ulceration of the epithelium was seen, and the underlying tumour was composed of round and poorly demarcated pleomorphic tumour cells. The cytoplasm was pale and the nuclei heterogeneous. Numerous mitoses were present. The tumour cells stained strongly for CD3. The final diagnosis was a peripheral T-cell lymphoma not otherwise specified (NOS).

Conclusions

This is the first described case of a solitary T-cell lymphoma NOS in the haired eyelid skin in a dog. Lymphoma should be considered in case of a persistent eyelid ulcer and a biopsy should be performed. T-cell lymphoma is generally an aggressive disease; however, indolent cases are well known, and as this case shows, complete excision of a solitary T-cell lymphoma can be curable. Canine cutaneous epitheliotropic T-cell lymphoma is an important differential diagnosis, which must be recognized as the prognosis is very poor and systemic treatment is mandatory. The sub-classification of canine lymphoma is not complete, and further studies are needed to identify lymphoma subgroups and provide treatment guidelines.

     

A note on the food of Amphinemoura sulcicollis (Plecoptera)

The plecopteran Amphinemoura sulcicollis can find sufficient food in the organic layer on stones as well as in leaves in streams. Microscopical observations have indicated that when feeding on detritus from stones, the fungi dominant on the detritus was assimilated. Beech leaves which had been submerged in stream water for 3 weeks are more attractive to the nymph than leaves that had been submerged for a few hours. Beech leaves which had been submerged 3 weeks in stream water and inoculated with a hyphomycete are more attractive to the nymph than beech leaves that had been submerged the same length of time in normal stream water.     

Insulins with built-in glucose sensors for glucose responsive insulin release.

Derivatization of insulin with phenylboronic acids is described, thereby equipping insulin with novel glucose sensing ability. It is furthermore demonstrated that such insulins are useful in glucose‐responsive polymer‐based release systems. The preferred phenylboronic acids are sulfonamide derivatives, which, contrary to naïve boronic acids, ensure glucose binding at physiological pH, and simultaneously operate as handles for insulin derivatization at LysB29. The glucose affinities of the novel insulins were evaluated by glucose titration in a competitive assay with alizarin. The affinities were in the range 15–31 mM (K_d), which match physiological glucose fluctuations. The dose‐responsive glucose‐mediated release of the novel insulins was demonstrated using glucamine‐derived polyethylene glycol polyacrylamide (PEGA) as a model, and it was shown that Zn(II) hexamer formulation of the boronated insulins resulted in steeper glucose sensitivity relative to monomeric insulin formulation. Notably, two of the boronated insulins displayed enhanced insulin receptor affinity relative to native insulin (113%–122%) which is unusual for insulin LysB29 derivatives. Copyright © 2004 European Peptide Society and John Wiley & Sons, Ltd.     

Linearity in the aggregate effects of multiple predators in a food web

Theory in community ecology often assumes that predator species have similar indirect effects and thus can be treated mathematically as a single functional unit (e.g. guild or trophic level). This assumption is questionable biologically because predator species typically differ in their effects, creating the potential for nonlinearities when they coexist. We evaluated the nature of indirect effects caused by three species of hunting spider predators, singly and in multiple species combinations, on grass and herb plants in experimental old-field food webs. Despite the potential for nonlinearity, indirect effects in different multiple predator combinations consistently did not differ significantly from the respective means of the single species effects. Thus, for this experimental system, the whole was simply the average of the parts. Consequently, models which abstract predator species as single trophic levels would successfully predict indirect effects in this system regardless of the composition of the predator fauna.