Neurotoxic and haemolytic activity of a protein isolated from Bacillus thuringiensis var. israelensis crystals

Abstract Two proteins (protein A and B) were isolated from Bacillus thuringiensis var. israelensis crystals using ion-exchange chromatography. Protein A was found to have haemolytic and neurotoxic activities. Inhibition of nerve conduction in the sixth abdominal ganglion of the American cockroach was observed following application of protein A. Protein A was found to be haemolytic to human and rabbit erythrocytes. Protein B did not exhibit any of these activities.     

Coelomomyces opifexi (Pillai & Smith). Coelomomycetaceae: Blastocladiales.

Summary Coelomomyces opifexi is a pathogen of two species of brackish mosquitoes in New Zealand, the endemic Opifex fuscus and the introduced Australian species Aedes australis. Since the activity of the fungus is confined to the south east coast of the South Island, which also corresponds to the present distribution pattern of Aedes australis in New Zealand, it is suggested that the Coelomomyces may have also been derived from Australian sources.The host species breed in supralittoral pools of rapidly fluctuating salinities ranging from fresh water to hypersaline conditions. Temperature, hydrogen ion concentration, salinity, pool size, biotic composition factors were compared between infection and non-infection pools. With the exception of salinity readings there was no significant difference in the two.Field studies showed that there was a correlation between a lower range of salinities and the appearance of infected larvae in the pool. A few supralittoral pools appear to be located in sheltered situations

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Zusammenfassung In Neuseeland ist Coelomomyces opifexi pathogen für zwei Arten brackiger Stechmücken, den endemischen Opifex fuscus und die eingeführte Australische Art Aedes australis. Da die Tätigkeit des Pilzes, wie die heutige Verbreitung von Aedes australis nur auf die südöstliche Küste der Südinsel beschränkt ist, wird vermutet, daß Coelomomyces auch australischer Herkunft ist.Die Wirtspecies erzeugen in Küstenlachen schnellveränderliche Salzhaltigkeiten wechselnd von frisch bis zu übersalzig. Faktore wie Temperatur, Ph, Salzhaltigkeit, Lachegröße und biotischer Aufbau in infizierten und nichtinfizierten Lachen sind verglichen worden. Dabei gab es keine bedeutenden Unterschiede außer dem Salzigkeitsgrad.Aus den dortigen Forschungen hat sich herausgestellt, daß es eine Wechselbeziehung zwischen einem niedrigen Salzhaltigkeitsbereich und der Erscheinung infizierter Larven gibt. Man hat verschiedene Lachen in beschützenden Lagen mit einem minimalen Meereseinfluß gefunden. Unter günstige Verhältnisse stellen sie eine Ansteckungsquelle dar.

     

Role of intracellular-free calcium in the cornified envelope formation of keratinocytes: differences in the mode of action of extracellular calcium and 1,25 dihydroxyvitamin D3

Extracellular calcium (Cao) and the steroid hormone 1,25(OH)2D, induce the differentiation of human epidermal cells in culture. Recent studies suggest that increases in intracellular free calcium (Cai) levels may be an initial signal that triggers keratinocyte differentiation. In the present study, we evaluated cornified envelope formation, the terminal event during keratinocyte differentiation, and correlated it with changes in the Cai levels during differentiation of keratinocytes in culture induced by Cao or 1,25(OH)2D. Keratinocytes were grown in different Cao concentrations (0.1 or 1.2 mM) or in the presence of 1,25(OH)2D (10(-11) to 10(-7) M), and the Cai levels were measured using the fluorescent probe Indo-1. Our results suggest that the induction of cornified envelope formation is associated with an increase in Cai level during calcium-induced differentiation. Cao and the calcium ionophore ionomycin acutely increased Cai and cornified envelope formation. In contrast, the effect of 1,25(OH)2D on increasing Cai levels and stimulating cornified envelope formation was long-term, requiring days of treatment with 1,25(OH)2D. Our data are consistent with other recent studies and support the hypothesis that Cao regulates keratinocyte differentiation primarily by acutely increasing their Cai levels. The role of calcium in the mechanism of action of 1,25(OH)2D on keratinocyte differentiation is less clear. The increase in Cai of keratinocytes during 1,25(OH)2D induced differentiation may be essential for or subsequent to its prodifferentiation effects.     

Coelomomyces psorophorae vartasmaniensis Couch+Laird (1988) (Coelomomycetaeceae: Blastocladiales), a fungal pathogen of the mosquitoAedes australis

The presence of synaptonemal complexes were checked in dividing chromosomes as evidence for meiotic division in germinating sporangia. Continuous urografin gradients were used to separate out the various phases of germinating sporangia, the nuclei were removed and embedded for ultrastructural studies. Meiotic inhibitors were applied to germinating sporangia to retard meiotic division to highlight the synaptonemal complexes. At an early phase of sporangial differentiation dividing nuclei developed with synaptonemal complexes. Meiotic inhibitors and stimulators may be used to control sporangial germination for an induction of a high meiospore count. This may be of crucial importance in the utilization of Coelomomyces spp. as a biological control agent of mosquito species.     

Tolypocladium cylindrosporum (Deuteromycotina: Moniliales), a fungal pathogen of the mosquito Aedes australis

The New Zealand strain of Tolypocladium cylindrosporum was cultured on Sabouraud dextrose agar medium under varying regimes of growth conditions. The isolate exhibited good tolerances to temperature (4–35 °C), pH (3–10) and salinity (0–7% NaCl). Optimal vegetative growth and sporulation were recorded between a temperature range of 20–30° C, pH of 5–6 and a salinity level of 0–2% NaCl. The North American isolate of the fungus showed similar tolerances, while the European isolate was less tolerant.