Toxicity of Bacillus thuringiensis var. israelensis for Simulium larvae, vectors of onchocerciasis]

On field trials in infested streams, the primary powder R 153-78 made of B. thuringiensis var. israelensis with a potency of 3,000 I.T.U. Aedes aegypti/milligramme is very toxic for Blackfly larvae, especially for Simulium damnosum s.l. larvae. The lethal concentration 100, in 24 h. is 0.2 X 10(-6) for a 10 min. treatment. This high toxicity, specific for Diptera larvae such as Mosquitoes and Blackflies, is related to the special characteristic of the bacterial crystal protein which has a clear serological and chemical individuality compared to the crystal proteins of the other B. thuringiensis serotypes essentially pathogenic for Lepidoptera larvae. These preliminary results are very promising and could lead, on further research, to the utilization of B. thuringiensis var. israelensis on large scale for onchoceriasis vector control in Africa.     

Cytological study of the action of Bacillus thuringiensis var. israelensis on mosquito larvae]

A comparison is made between the cytopathological effects of B. thuringiensis var. israelensis on Aedes aegypti larvae and the cytopathological effects of the other varieties of B. thuringiensis on Lepidoptera larvae. The same primary action is observed, with the loss of integrity of the gut epithelium, the cells of which appear swollen, distorted and finally burst.     

Toxicity of Bacillus thuringienses var. israelensis for larvae of Aedes aegypti and Anopheles stephensi]

The comparative study of the larvicidal action of B. thuringiensis var. israelensis on A. aegypti and A. stephensi shows the greater sensitivity of A. aegypti, with 100% of mortality in 30 to 40 min. at high doses. But, for both species of Mosquito, the toxicity of these bacteria is very high, as shown by the mortality regression curves and by the LC50. This toxicity is associated with the crystals and can be extracted from them by dilute alkali solution, like the general case of the other serotypes of B. thuringiensis. In contrast with these serotypes, B. thuringiensis var. israelensis is not pathogenic to the tested larvae of Lepidoptera.     

A new variety of Bacillus thuringinesis very toxic to mosquitoes: B. thuringiensis var. israelensis serotype 14]

A new strain of B. thuringiensis is described, the flagllar antigen of which is a new one named H14. This strain produces unusual crystals, with all shapes and sizes, and shows a high toxicity for larvae of Aedes aegypti.     

Monoclonal antibodies against functionally distinct sites on the delta-endotoxin ofBacillus thuringiensis var.thuringiensis

Summary Monoclonal antibodies against the toxic units ofBacillus thuringiensis delta-endotoxin were raised by the hybridoma technique and detected by an indirect enzyme-linked immunosorbent assay (ELISA). Out of 5 positive clones, I was found to secrete antibodies which inactivate the toxin.     

Bacillus thuringiensis delta-endotoxin: evidence that toxin acts at the surface of susceptible cells

Enzymically activated delta-endotoxin of Bacillus thuringiensis covalently bound to Sephadex beads, has the same effect on insect cells in tissue culture as free toxin. The effect is prevented by antitoxin antibody and heat denaturation and is not due to a nonspecific protein effect, the beads, or toxin released from the beads. The toxin, therefore, probably acts at the cell surface.     

Morphologic alterations induced by aflatoxin B1 in Bacillus thuringiensis (Berliner)]

Significative ultrastructural alterations shown in aflatoxin B1, treated cells of Bacillus thuringiensis are: increase of number of mesosomes which are hypertrophied, decrease of ribosomes and formation of imperfect cell septa.     

Action of Bacillus thuringiensis preparation against larch bud moth, Zeiraphera diniana (Gn.), enhanced by beta-exotoxin and DDT.

Addition of either DDT or the supernatant of a centrifuged liquid culture of Bacillus thuringiensis, serotype H1, containing beta-exotoxin, enhanced the action of the bacterial preparation Thuricide 90 T against larvae of the larch pest Zeiraphera diniana, increasing mortality from 53% to more than 80%. Since DDT alone produced 57% mortality, its combined action corresponds to independent action. The preparation of beta-exotoxin, on the other hand, had only little effect alone but synergized the action of the bacterial preparation considerably.     

Interconversion of T-2636 antibiotics produced byStreptomyces rochei var.volubilis

Zusammenfassung Mit angereicherten Enzympräparaten vonStreptomyces rochei var.volbulis sowie einigen Pilzen Hessen sich die Antibiotica T-2636 A (I) und D (III) zu C (II) beziehungsweise F (IV) reversibel desacetylieren. Die Antibiotica (III) und (IV) wurden auch mit dem EnzymS. rochei var.volubilis dehydriert.     

Les besoins en facteurs de croissance deMucor Ramannianus var.angulisporus Naoumoff

Summary Mucor Ramannianus is auxo-heterotrophic for the thiazol of aneurine. The var.angulisporus is auxo-autotrophic.     

The toxicity of two Bacillus thuringiensis delta-endotoxins to gypsy moth larvae is inversely related to the affinity of binding sites on midgut brush border membranes for the toxins

The delta-endotoxin from Bacillus thuringiensis subspecies kurstaki strain HD1-9 is almost 400 times more potent than the delta-endotoxin from strain HD-73 as a gypsy moth larvicide. The two delta-endotoxins compete for a high-affinity binding site on the brush border membrane of larval gypsy moth midguts. The affinity for the delta-endotoxin from strain HD-73 is much greater than the affinity for the delta-endotoxin from strain HD1-9.     

Occurrence of Rhodoquinone-9 in the muscle of ascaris lumbricoides var. suis

Zusammenfassung Es gelang, aus der Epithelmuskelzelle vonAscaris lumbricoides var.suis Rhodochinon (Methoxylgruppe in Ubichinon mit einer Aminogruppe substituiert) zu extrahieren und kristallin zu gewinnen. Die Spektralmessungen (UV-, IR-, Massen-Spektren) ergeben, dass es sich beim Rhodochinon um Rhodochinon-9 handelt.     

Arctigenin-4′-β-gentiobioside fromTrachelospermum asiaticum var. intermedium

Zusammenfassung Eine neue Lignansubstanz, Arctigenin-4--gentiobiosid C₃₃H₄₄O₁₆·H₂O wurde als weisses Pulver von Smp. 174–176° aus Stengeln vonTrachelospermum asiaticum Nakai var.intermedium Nakai gewonnen.     

The benthic red alga Ceramium ciliatum var. robustum (J.Ag.) G. Mazoyer is a remarkable biological indicator of littoral mercury pollution]

The study of mercury composition of red Algae Ceranium ciliatum var. robustum, comparatively with other marine organisms and considering its growth and the extent of pollution at various harvesting points: reveals that this seaweed constitutes a conspicuous biological indicator for the littoral mercury pollution.     

Novel insecticidal toxins from nematode-symbiotic bacteria

The current strategy of using transgenic crops expressing insecticidal protein toxins is placing increasing emphasis on the discovery of novel toxins, beyond those already derived from the bacterium Bacillus thuringiensis. Here we review the cloning of four insecticidal toxin complex (tc) encoding genes from a different bacterium Photorhabdus luminescens and of similar gene sequences from Xenorhabdus nematophilus. Both these bacteria occupy the gut of entomopathogenic nematodes and are released into the insect upon invasion by the nematode. In the insect the bacteria presumably secrete these insecticidal toxins, as well as a range of other antimicrobials, to establish the insect cadaver as a monocultural breeding ground for both bacteria and nematodes. In this review, the protein biochemistry and structure of the tc encoding loci are discussed in relation to their observed toxicity and histopathology. These toxins may prove useful as alternatives to those derived from B. thuringiensis for deployment in insect-resistant transgenic plants.     

Comparison of glutamate dehydrogenase and glutamine synthetase activities in the roots and aerial organs of an obligate halophyte: Suaeda maritima var. macrocarpa and a glycophyte: Phaseolus vulgaris, grown in presence of different concentration of NaCl]

The glutamate dehydrogenase and glutamine synthetase activities of an obligate halophyte, Suaeda maritima var. macrocarpa and a glycophyte. Phaseolus vulgaris are compared in function of salinity (increasing concentrations of NaCl) of the culturing solution. In culture, addition of NaCl stimulates glutamine synthetase activity and lowers glutamine dehydrogenase activity in the aerial organs and in the roots of Suaeda as opposed to what is observed in the glycophyte. Hence the obligatory halophily of Suaeda is related to an increase of the glutamine synthetase activity in a sal-trich medium corresponding to the stimulation of nitrate reductase and proteogenesis.