Lytic activity from schistosomes: interactions with blood cells

1. The schistosome lytic agent hemolyzed animal red blood cells (RBCs) containing high concentrations of membrane phosphatidyl choline (dog, mouse, and rat) more efficiently than RBCs having no phosphatidyl choline (goat and sheep). 2. Human mononuclear cells lost viability in the presence of the schistosome lytic agent. 3. Preincubating the lytic agent with phosphatidyl choline or bovine serum albumin reduced its lytic activity. 4. Extracellular albumin protected the RBCs from schistosome induced hemolysis. 5. Pretreatment of the RBCs with various proteases enhanced lysis by 10-30%.     

Absorption, excretion and tissue distribution of natural organic and inorganic zinc-65 in the rat.

The absorption and tissue distribution of organic and inorganic forms of 65-Zn were studied in the rat following single tracer oral doses. Rats dosed with 65-Zn grown into young corn and rye plants (organic form) absorbed and retained more 65-Zn in tissues than those given 65-Zn mixed with tissue paper (inorganic forms). A part of the beneficial effect was evident when 65-Zn was mixed with forage. The relatively high absorption values indicate that both forms were readily available, and thus incorporating zinc into young forage protein is not of major practical importance.     

Floristic knowledge and needs in Pacific Tropical America

The tropical American region of the Pacific Basin is undoubtedly the Basin’s most poorly known region floristically. It is probably also the richest in number of species. I present here a brief history of floristic work in the area, a review of the region’s ecological geography and a summation of the interaction of history and ecology which has led to the present day situation. The current status of floristics in the region is assessed from this perspective and some proposed directions of future floristic research are suggested.     

Red squill (Urginea maritima,Liliaceae)

Red squill(Urginea maritima, Liliaceae) was introduced to North American agriculture during World War II. Experimental plantings were started at Ensenada, Baja California, and later moved to La Jolla, California, as a USDA Agricultural Research Service project. In 1960 ARS turned the red squill bulbs over to four private groups. Cultivation and increase of clonal germplasm were continued by the Gentry Experimental Farm, which in 1979 was joined by collaborators for more complete studies in chemistry, propagation, and marketing. Scilliroside was confirmed as the principal toxicant. A high-performance, liquid-chromatographic method for assaying the glycosides and aglycones was developed. Growth trials in southern California established the species as well adapted to the California climate. Test plantings in Arizona indicate it as successful on irrigated, well-drained soils. It is a good producer of a rodenticide and of flowers for the cut-flower trade. Our studies indicate it could be a profitable new crop on the dry-farmed grain lands of southern California.     

Microarray-Based Analysis of Microbial Community RNAs by Whole-Community RNA Amplification

A new approach, termed whole-community RNA amplification (WCRA), was developed to provide sufficient amounts of mRNAs from environmental samples for microarray analysis. This method employs fusion primers (six to nine random nucleotides with an attached T7 promoter) for the first-strand synthesis. The shortest primer (T7N6S) gave the best results in terms of the yield and representativeness of amplification. About 1,200- to 1,800-fold amplification was obtained with amounts of the RNA templates ranging from 10 to 100 ng, and very representative detection was obtained with 50 to 100 ng total RNA. Evaluation with a Shewanella oneidensis Δfur strain revealed that the amplification method which we developed could preserve the original abundance relationships of mRNAs. In addition, to determine whether representative detection of RNAs can be achieved with mixed community samples, amplification biases were evaluated with a mixture containing equal quantities of RNAs (100 ng each) from four bacterial species, and representative amplification was also obtained. Finally, the method which we developed was applied to the active microbial populations in a denitrifying fluidized bed reactor used for denitrification of contaminated groundwater and ethanol-stimulated groundwater samples for uranium reduction. The genes expressed were consistent with the expected functions of the bioreactor and groundwater system, suggesting that this approach is useful for analyzing the functional activities of microbial communities. This is one of the first demonstrations that microarray-based technology can be used to successfully detect the activities of microbial communities from real environmental samples in a high-throughput fashion.     

Thoracic splenosis. Diagnosis of a case by fine needle aspiration cytology

Fine needle aspiration cytology was used to study chest wall nodules in a patient who presented with fever, cough, pleuritic chest pain and cytomegalovirus infection and who had a previous history of abdominal trauma. The finding of splenic red pulp and white pulp in the aspirate, combined with the results of a radionucleotide liver-spleen scan, led to a diagnosis of thoracic splenosis, a relatively rare condition. Splenosis is thought to result from transplantation of splenic tissue after trauma and may provide some added protection against certain infectious conditions, both of which were present in this case.     

Differences in conformational stability between native and phosphorylated acetylcholinesterase as evidenced by a monoclonal antibody.

Monoclonal antibody 25B1 generated against diisopropyl phosphorofluoridate inhibited fetal bovine serum acetylcholinesterase has been extensively characterized with respect to its anticholinesterase properties. This antibody demonstrated considerably different properties from previously reported inhibitory antibodies raised against acetylcholinesterase in terms of the degree of inhibition (greater than 98%), the high degree of specificity, and the stability of the antigen-antibody complex. Monoclonal antibody 25B1 appears to be directed against a conformational epitope located in close proximity to the catalytic center of the enzyme and was found to be most suitable for studying the stabilization of the active site of acetylcholinesterase against denaturation by heat or guanidine following phosphorylation by organophosphorus anticholinesterase compounds. This approach allowed the determination of stability rank order of various phosphorylated acetylcholinesterases. Among all the organophosphates tested, the combination of a methyl group and a negatively charged oxygen attached to the P atom, CH3P(O)(O-)-AChE, conferred the greatest protection to the active site of aged or nonaged organophosphoryl conjugates of acetylcholinesterase.