The effect of mobbing vocalizations on risk perception in common mynas (Acridotheres tristis)

Journal of Ethology - Animals emit predator-elicited calls in response to potential predation threats. These vocalizations induce a variety of anti-predator behaviors in conspecific receivers...     

Influence of prey species and stages on predatory efficiency and development of two phytoseiid mites

The effect of prey species and the different stages of prey on the predatory efficiency and biology of the phytoseiid mites,Amblyseius gossipi Elbadry andTyphlodromus mangiferus sp. n. was studied. It was found that feeding either predator onTetranychus cucurbitacearum (Sayed) promoted faster development and a higher rate of oviposition than rearing on the twospotted spider mite,T. urticae (Koch). Different stages of both prey species also produced different responses in the biological activities of these predaceous mites.

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Résumé On a étudié l'effet de l'espèce de la proie et de ses différents stades sur l'efficacité et la biologie des acariens phytoseiides,Amblyseius gossipi Elbadry etTyphlodromus mangiferus sp. n. Il a été constaté que l'alimentation des 2 prédateurs avecTetranychus cucurbitacearus (Sayed) assure un dévelopment plus rapide et une fécondité plus élevée que leur élevage surT. urticae (Koch). Les différents stades de ces 2 proies produisent des réponses différentes dans les activités biologiques des 2 acariens prédateurs.

     

Esterogenic effect of zearalenone on the uterine acetyl cholinesterase in female rats

A single dose of zearalenone (10 g/g LBW) was injected intraperitoneally to Wistar Albino rats at the age of 50–100 days. The uterine acetyl cholinesterase enzyme was significantly increased in the treated animals compared to that in the controls. Therefore, zearalenone would be considered as an esterogenic effector for increasing the uterine acetyl cholinesterase which enhances uterine relaxation and subsequently improves its function for pregnancy in prematured-animals.Unlike estradiol, it was interesting to find that the estrogenicity of zearalenone was increased by the moderating progesterone hormone. Moreover, it was revealed in this study that the injected dose of zearalenone had no deleterious effects on the pregnant rats at 10–12 days period of gestation. The harmful effects of zearalenone on pregnant animals cited in the literature (11, 13, 19) were reviewed.     

Production of trichothecene and non-trichothecene mycotoxins by Fusarium species isolated from maize in Minnesota

Eighty-two cultures of Fusarium species isolated in 1986 from moldy maize in Minnesota were each cultured on rice for 4 weeks and found to produce the following mycotoxins: F. graminearum isolates, deoxynivalenol (DON, 4–225 g/g), 3-acetyldeoxynivalenol (3-ADON, 2–4g/g), 15-acetyldeoxynivalenol (15-ADON, 1–35 g/g) and zearalenone (ZEA, 5–4350 g/g); F. moniliforme, fusarin C (detectable amounts to 1000 g/g); F. mòniliforme, F. oxysporum, F. proliferatum and F. subglutinans isolates, moniliformin (15–6775 g/g); F. moniliforme, F. proliferatum, and F. subglutinans isolates, fusaric acid (detectable amounts). Other mycotoxins screened for in each rice sample and not detected were T-2 toxin, HT-2 toxin, neosolaniol, T-2 tetraol, nivalenol, fusarenon-X, scirpenols, alpha and beta trans-zearalenols, wortmannin, and fusarochromanone. The rat feeding bioassay indicated that other, unidentified toxins may be present.     

Effects of Metals on a Range of Streptomyces Species

A plate diffusion method was used to assess the tolerance of 28 mesophilic and 4 thermophilic species of streptomycetes to eight metals. This method allowed a qualitative screen of the effects of the metals on growth, on sporulation, and in some cases, on secondary metabolite production. Tolerant and sensitive species were identified, some of which exhibited the same response (i.e., tolerance or sensitivity) to a number of metals. Experiments in liquid culture were used to quantify the precise concentration ranges of the metals at which the most tolerant or sensitive species could grow. Distribution profiles of the sensitivities of all species examined toward different metals revealed that the order of toxicity was Hg > Cd > Co > Zn > Ni > Cu > Cr > Mn.     

A minority of 46,XX true hermaphrodites are positive for the Y-DNA sequence including SRY

Summary A total of 30 cases of 46,XX true hermaphroditism was analysed for Y-DNA sequences including the recently cloned gene for male testis-determination SRY. In 3 cases, a portion of the Y chromosome including SRY was present and, in 2 cases, was localised, to Xp22 by in situ hybridisation. Since previous studies have shown that the majority of XX males are generated by an X-Y chromosomal interchange, the Xp22 position of the Yp material suggests that certain cases of hermaphroditism can arise by the same meiotic event. The phenotype in the 3 SRY-positive cases may be caused by X-inactivation resulting in somatic mosaicism of testis-determining factor expression giving rise to both testicular and ovarian tissues. Autosomal or X-linked mutation(s) elsewhere in the sex-determining pathway may explain the phenotype observed in the remaining 27 SRY-negative cases.     

Mycotoxins and Fusarium spp. associated with infected ears of corn in Minnesota.

Five Fusarium species were isolated from the grain of dent corn (Zea mays) selected from 20 of 32 damaged fields in 10 counties in Minnesota on the basis of hyphal growth visible on kernels in the field. Three mycotoxins were identified in the infected ears: zearalenone, deoxynivalenol, and 15-acetyl-deoxynivalenol. This is the first report of the presence of 15-acetyl-deoxynivalenol on corn ears in the field prior to harvest and in combination with deoxynivalenol and zearalenone. Ninety-nine cultures were selected from colonies growing from kernels on an agar medium; 30% of the cultures were F. graminearum, 23% were F. subglutinans, 20% were F. moniliforme, 14% were F. oxysporum, and 12% were F. proliferatum.