Protein Synthesis in Isolated Symbionts from the Flagellate Protozoon Crithidia deanei1

Here we describe a method that allows the isolation of intact trypanosomatid symbionts in amounts sufficient for biochemical analysis. The isolated symbionts retain their characteristic morphological features and are reasonably free of subcellular debris. They actively incorporate [³H]leucine and [³⁵S]methionine into proteins. Chloramphenicol and rifampicin at 50 μg/ml almost completely inhibit the incorporation of protein precursors. The inhibition of protein synthesis by the antibiotics provides direct evidence for the existence of a prokaryotic protein-synthesizing system in this unusual intracellular structure. The pattern of protein synthesis of the isolated symbionts is complex. Several symbiont polypeptides are absent or poorly represented in the flagellate.     

Life cycle differences among Brazilian sandflies of the Lutzomyia longipalpis sibling species complex

The developmental cycles of five Brazilian populations of the Lutzomyia longipalpis Lutz & Neiva species complex (Diptera: Psychodidae) were compared under laboratory conditions. Three of the populations were derived from insects collected in allopatric sites at Natal (Rio Grande do Norte State), Jacobina (Bahia State) and Lapinha Cave (Minas Gerais State). The other two originated from Sobral (Ceará State), where the males of two sympatric species can be distinguished by the presence of one (1S) or two (2S) pairs of abdominal spots. The results of the present study clearly show that all three populations whose males produce C₁₆ pheromones and use pulse-type copulation songs (Jacobina, Lapinha Cave and Sobral 1S) are more easily adapted to the colonization conditions used in our laboratory, producing larger egg batches, with higher survival and an overall faster developmental cycle. This contrasts with populations producing C₂₀ male pheromones and using burst-type copulation songs (Natal and Sobral 2S) that produce smaller egg batches, have higher oviposition mortality and a slower rate of development under identical laboratory conditions. In conclusion, these phenological differences are a further indication of the differentiation of the siblings within the Lu. longipalpis species complex.     

Colonization of cellulose membranes by species of Verticillium

Verticillium dahliae Kleb. (from Brussels sprouts), non-pathogenic to tomato, and V. tricorpus Issac, a virulent pathogen to tomato, differed in their ability to colonize samples of commercial Cellophane, their rate of colonization being dependent upon external sources of carbohydrate. Cellophane and filter paper were both utilized in culture as the sole carbon source and it appears that both fungi have identical cellulase enzyme systems. Prolonged growth of the isolates is liquid medium containing sucrose as the carbon source resulted in lysis of the mycelium, which coincided with the production of polysaccharide material in culture.     

The Effect of Cultural Operations on the Composition of the Xylem Sap of Tea Plants Recovering from Pruning

Complete removal of foliage-bearing branches from tea plantsrecovering from pruning at low altitudes has been observed toresult in a scorching of the newly-developing buds and shoots.Studies on the xylem sap composition have revealed that thereis a very sharp increase in the amino-N content of the sap.The relationship between the sap composition and the physiologyof the plant is discussed.     

Guidelines for the Description of New Species of Lower Trypanosomatids1

Morphological, cultural, and biochemical criteria that have been used in describing lower trypanosomatids, genera Blastocrithidia, Crithidia, Leptomonas, Herpetomonas, Rhynchoidomonas, and Phytomonas are reviewed. Kinetoplast structure, carbohydrate utilization, electrophoretic mobilities of isoenzymes, and kDNA fingerprinting are among the recommended criteria for species differentiation. Temperature, pH, and osmolarity tolerance are useful growth parameters. Generic placement may be assisted by the determination of nitrogenous excretion products and ornithine-arginine cycle enzymes.     

Five Trypanosomatid Species of Insects Distinguished by Isoenzymes*

SYNOPSIS Blastocrithidia culicis, Crithidia deanei, Crithidia fasciculata, Herpetomonas samuelpessoai, Leptomonas seymouri and Leishmania tarentolae grown in cultures were compared by electrophoretic mobility for isoenzymes in 6 enzymes. All species were found distinct in these characteristics. Endosymbiotic C. deanei, which was identical to the aposymbiotic C. deanei in 5 enzymes, had an extra band in aspartate aminotransferase. No differences in isoenzymes were found between members of one species maintained in 2 different culture media.     

Verticillium wilt of sainfoin

A wilt disease of sainfoin caused by Verticillium Dahliae Kleb. is described, and it is shown that the fungus can penetrate sainfoin seedlings through unwounded roots as well as through ruptures caused by the emergence of lateral rootlets. V. Dahliae was isolated from naturally infected soil only in June, July and August, although another species, V. nigrescens , was obtained throughout the year.
Comparative studies of the longevity of cultures of V. Dahliae, V: albo-atrum and V. nigrescens proved that all are viable for at least 3 years on agar media. On sterilized wheat grains V. Dahliae dies within 8 weeks after inoculation, V. albo-atrum and V. nigrescens within 12 weeks, while the hyaline variants of the first two remain viable for 6 months.
Evidence was obtained that in artificially inoculated soil V. Dahliae persists mainly as microsclerotia. The fungus may also exist in the soil as hyaline mycelium or conidia, but only for a relatively short time.
The incidence of this disease in sainfoin is reduced by an increase in soil-water content, but is unaffected by the application of lime to the soil.     

Isolation and characterization of microsatellite loci in Amazonian red‐handed howlers Alouatta belzebul (Primates,Plathyrrini)

Ten highly polymorphic microsatellite loci are described for Amazonian red‐handed howlers (Alouatta belzebul), an endemic Brazilian primate species subject to intense hunting pressure. The number of alleles observed in 30 individuals ranged from nine to 20, and observed heterozygosity varied from 0.35 to 0.93. No linkage associations were evident from pairwise comparisons of loci. These microsatellites offer a powerful tool for fine‐scale studies of genetic structure in both captive colonies and wild populations of red‐handed howlers.     

Multivariate Interpretation of the Distribution of Nitrogen-fixing Blue--green Algae in Rice Soils in Central Sri Lanka

The ecology of nitrogen fixing blue-green algae in rice fieldsof Central Sri Lanka was studied using multi-variate techniquesof analyses. In this study 73 strains of heterocystous blue—greenalgae, belonging to 21 genera were isolated and the distributionof the 46 most abundant strains was examined in relation toecological parameters. Besides pedological factors such as pH, water holding capacityand available phosphorus; environmental factors including rainfalland altitude have shown up as parameters influencing the distributionof the algal species. On the other hand, soil organic carbon,total nitrogen, potassium and calcium, do not appear to playan important role in determining the composition of the algalflora. While certain algal species were ubiquitous in their distributionsome were restricted, and a few even showed a tolerance to standswith low soil pH and low levels of phosphorus. The agronomicpotential of such species is of value especially in relationto rice-growing soils of this District, where low pH and lowlevels of phosphorus are major limiting factors for the profusegrowth of blue—green algae. Blue-green algae, nitrogen fixation, Sri Lanka, rice-growing soils, multivariate analysis