Israeli Strain Research Articles

Dissemination of leishmanias to the organs of Syrian hamsters following intrasplenic inoculation of promastigotes

Four strains of leishmanial promastigotes were inoculated intrasplenically into male Syrian hamsters ( Mesocricetus auratus). The dissemination of the parasites as amastigotes to various organs was followed at closely spaced intervals for 3.5 mo. An Israeli strain of Leishmania tropica and a strain isolated in Israel from a gerbil ( Meriones shawi) displayed practically identical distribution patterns. Migration was outward from the spleen to the body surface, where intense multiplication of the amastigotes occurred, primarily in the ear pinnae and in the extremities of the limbs. A cryptic visceral infection persisted in the spleen, and most of the internal organs studied also developed cryptic infections. The bone marrow became rather heavily infected, and the epididymis, exceptionally heavily infected. An Indian strain of L. donovani led to a severe visceral infection in the spleen, liver, and bone marrow; and to mild to cryptic infections in most of the other visceral organs studied. However, no invasion of the genitalia occurred, nor did the body surface become infected. An Ethiopian strain of diffuse cutaneous leishmaniasis (DCL) was noninfective to Syrian hamsters, following either the intrasplenic or the intradermal inoculation of promastigotes.

The comparative morphology, specific status and host compatibility of two geographical strains of Callosobruchus chinensis L. (Coleoptera, Bruchudae)

Abstract Strains of Callosobruchus chinensis (L.) from Israel and Japan which had been in culture for several years were compared. The main morphological differences were that the Japanese strain had the male antennae pectinate, the pubescence of the median lobes of the prothorax completely white, and a dark patch on each of the hind femora. The israeli strain had the male antennae strongly serrate, golden pubescence on the anterior part of the prothoracic median lobes, and the hind femora completely testaceous. In inter-strain crosses the F 1 and F 2 generations were both fertile, and inter-strain fertility and F 1 viability was high, without significant differences in reciprocal crosses. No evidence of intra-strain preference in mating was obtained. Attempts to breed both strains on a number of soybean varieties failed, but the Israeli strain showed partial larval development although none reached pupation. An evaluation of the known chemical composition of soybean was undertaken and by compounding artificial beans and attempting to breed C. chinensis in them, further evidence on the incompatibility of the species with this legume was obtained. This was compared with the breeding rate of Tribolium castaneum , an insect known to be insensitive to the extremes of protein and carbohydrate concentration as are found in soybeans. The evidence indicates that C. chinensis does not present a hazard to soybean production, but the genetic nature of the Israeli strain may have economic implications.

On the chemical composition of some unicellular algae

The gross chemical composition of the golden-brown algae, Chrysochromulina kappa, Chrysochromulina polylepis, Prymnesium parvum; the yellow-green alga, Olisthodiscus sp.; and the green alga Pedinomonas minor, are given in terms of amounts per average cell. The following constituents were assayed: cell volume, dry weight, protein, lipid, carbohydrate, deoxyribonucleic acid, ribonucleic acid, phospholipid, acid-soluble phosphorus, phosphoprotein phosphorus, and chlorophylls a, b and c. Two strains of Prymnesium parvum were assayed and gave similar results. When cultures of the Israeli strain of P. parvum grown in constant light were placed in darkness no very marked change in average cell composition other than a drop in carbohydrate content was produced, whereas when the alga had been previously grown with a regimen of 8 hr darkness per 24 hr there was a smaller drop in carbohydrate content on darkening (the initial carbohydrate content being only about half that of cells grown in constant illumination) and also a marked drop in lipid. This could be interpreted as indicating that carbohydrate is the first food reserve to be utilized, after which lipid is consumed. It appears probable that much of the carbohydrate in the cultures grown with light and dark periods is not available as reserve food. No indication of the nature of the fish toxin found on darkening cultures of P. parvum, grown in constant illumination, was obtained by studying changes in gross chemical composition.

The effects of temperature on the early vegetative growth of Phalaris canariensis L. and P. tuberosa L.

Seedlings of Phalaris canariensis and P. tuberosa were grown in pots outdoors and under glass-house conditions in experiments at Canberra. Sigmoid curves expressed the increase in total dry weight, dry weight of plant parts, and tiller number for both species grown outdoors for 5 months. Phase 1 — the vegetative phase of growth — ended on about September 18 for P. canariensis and September 12 for P. tuberosa. Subsequent experiments were concerned with the effects of temperature on this growth phase. In experiments lasting for up to 44 days, both species were grown under natural (winter) conditions of light intensity and day length (less than 12 hr) and 16 combinations of day and night temperature. The optimum regime for dry weight production — 24/18–19°C — did not correspond with that optimal for tiller initiation. Highest tiller numbers were obtained when night temperature exceeded day temperature (19/22° or 19/24°), or approached the optimum day temperature (24/22° or 24/24°), or there was a relatively large fluctuation between day and night temperature (28/18°, for example). P. canariensis outyielded P. tuberosa under optimum temperature conditions, but P. tuberosa appeared to be less sensitive to night temperatures of 22–24°. No consistent trends in the effects of day or night temperature on the nitrogen content of tops, leaf length, leaf breadth, or the ratio leaf length/breadth were obtained. Leaf size and shape were, however, influenced by temperature. A comparison of the growth of the Australian commercial P. tuberosa was made with that of strains from Israel and Algeria under six temperature regimes. Under cold and cool conditions, the Algerian strain resembled the Australian strain, both being outyielded by the Israeli strain. Under a regime of 28/23°, however, the Algerian and Israeli strains were adversely affected, the latter more than the former. In nutrient culture solution, a root temperature of 20° approached the optimum for dry weight production and tiller initiation by P. canariensis more nearly than one of either 12° or 27°, ambient temperature being 24/20°. Leaf size was also influenced by root temperature.