A procedure for large-scale isolation of RNA-free plasmid and phage DNA without the use of RNase

A preparative procedure for the large-scale isolation of plasmid DNA without the use of RNAse is described. Crude plasmid DNA is prepared using a standard boiling method. High-molecular-weight RNA is removed by precipitation with LiCl, and low-molecular-weight RNA is removed by sedimentation through high-salt solution. The procedure is inexpensive, rapid, simple, and particularly suitable for processing several large-scale preparations simultaneously. A similar procedure has been developed for preparation of lambda-phage DNA.     

Serial circulating immune complex values and development of metastatic disease in breast cancer and malignant melanoma patients

Summary A polyethylene glycol precipitation technique was used to determine the levels of circulating immune complexes (CIC) in breast cancer and melanoma patients. All patients in the study had undergone surgery and were free of distant metastatic disease. CIC were measured at two to four time intervals, of 3 to 6 months each, over an average follow-up period of 13.5 months (range 7–20 months). In both groups of patients, metastatic disease developed with a higher frequency in patients who had undetectable CIC levels throughout the follow-up period or had become negative at the time metastases were discovered.     

Resistance of wild wheat to stripe rust: Predictive method by ecology and allozyme genotypes

From 114 accessions of wild emmer wheat from 11 sites in Israel, known for their allozymic variation (Nevo & al. 1982), individual genotypes were tested for resistance to one isolate of stripe rust both in the seedling stage in a growth chamber and in the adult plant stage in the field. The results indicate that resistance to stripe rust in seedlings and adults are significantly correlated (r_s = 0.40, p < 0.001). Genetic polymorphisms of resistance to stripe rust vary geographically and are predictable by climatic, as well as allozymic markers. Three variable combinations of rainfall, evaporation, and temperature explain significantly 0.40–0.53 of the spatial variance in disease resistance to stripe rust, suggesting the operation of natural selection. Several allozyme genotypes are significantly associated with disease resistance. We conclude that natural populations of wild emmer wheat in Israel contain large amounts of disease resistance genes. These populations could be effectively screened and then utilized by the phytopathologist for identifying resistant genotypes and producing new resistant cultivars.Patterns of Resistance of Wild Wheat to Pathogens in Israel II.     

The Sec1 Family: A Novel Family of Proteins Involved in Synaptic Transmission and General Secretion

Abstract: The Sec1 family, a novel family of proteins involved in synaptic transmission and general secretion, is described. To date, 14 members of this family have been identified: four yeast proteins, Sec1, Sly1, Slp1/Vps33, and Vps45/Stt10; three nematode proteins, Unc-18 and the homologues of Sly1 and Slp1; the Drosophila Rop; and six mammalian proteins, the rat Munc-18/n-Sec1/rbSec1A and rbSec1B, the mouse Munc-18b/muSec1 and Munc-18c, and the bovine Munc-18 and mSec1. The mammalian proteins share 44–63% sequence identity with the nematode Unc-18 and Drosophila Rop proteins and 20–29% with the yeast proteins and their nematode homologues. The Sec1 proteins are mostly hydrophilic and lack a transmembrane domain. Nevertheless, Sec1 proteins are found as membrane-bound proteins. Some of them are also found as soluble, cytoplasmic proteins. Binding of the rat brain Sec1 to the presynaptic membrane may be due to strong interaction with syntaxin, an integral component of this membrane. The rat brain Sec1 is also bound to Cdk5, a neural cyclin-dependent kinase. The Sec1 proteins play a positive role in exocytosis. Loss of function mutations in SEC1 , SLY1 , or SLP1 result in blocking of protein transport between distinct yeast subcellular compartments. Inactivation of unc-18 and rop results in inhibition of neurotransmitter release and, in the case of rop , inhibition of general secretion as well. In addition, studies of Rop and n-Sec1 indicate that they also play a negative role in synaptic transmission, mediated by their interaction with syntaxin. A working model addressing the dual regulative role of the Sec1 proteins in secretion is presented.     

Correlation between cell density,membrane fluidity,and the availability of transferrin receptors in friend erythroleukemic cells

Undifferentiated Friend erythroleukemic cells (FL cells) acquire membrane microviscosity ( ), in accord with the culture cell density. At low cell density poise, whereas at confluency it increases to poise. Concomitantly, the total number of available transferrin receptors per cell decreases by about 80% upon increase in cell density. Modulation of membrane microviscosity, by artificial alteration of the membrane cholesterol level, mediates similar modulations of the availability of the transferrin receptors. The correlation between the availability of the transferrin receptors and the membrane lipid fluidity may take part in the overt decrease in iron uptake by erythroid cells along the erythropoiesis pathway.     

Genetic control of susceptibility to experimental allergic encephalomyelitis in mice

The genetic control of susceptibility to experimental allergic encephalomyelitis (EAE) was studied in mice. The results indicate that sensitivity to disease is not inherited in a simple Mendelian dominant way. Susceptibility to EAE is governed by genes located outside of the major histocompatibility complex and not byH-2-linkedIr genes. No correlation was observed between susceptibility to disease and the cellular immune response toward the small encephalitogenic protein.     

A high density physical map of chromosome 1BL supports evolutionary studies,map-based cloning and sequencing in wheat

Background

As for other major crops, achieving a complete wheat genome sequence is essential for the application of genomics to breeding new and improved varieties. To overcome the complexities of the large, highly repetitive and hexaploid wheat genome, the International Wheat Genome Sequencing Consortium established a chromosome-based strategy that was validated by the construction of the physical map of chromosome 3B. Here, we present improved strategies for the construction of highly integrated and ordered wheat physical maps, using chromosome 1BL as a template, and illustrate their potential for evolutionary studies and map-based cloning.

Results

Using a combination of novel high throughput marker assays and an assembly program, we developed a high quality physical map representing 93% of wheat chromosome 1BL, anchored and ordered with 5,489 markers including 1,161 genes. Analysis of the gene space organization and evolution revealed that gene distribution and conservation along the chromosome results from the superimposition of the ancestral grass and recent wheat evolutionary patterns, leading to a peak of synteny in the central part of the chromosome arm and an increased density of non-collinear genes towards the telomere. With a density of about 11 markers per Mb, the 1BL physical map provides 916 markers, including 193 genes, for fine mapping the 40 QTLs mapped on this chromosome.

Conclusions

Here, we demonstrate that high marker density physical maps can be developed in complex genomes such as wheat to accelerate map-based cloning, gain new insights into genome evolution, and provide a foundation for reference sequencing.     

New developments in the sociology of Palestinian citizens of Israel: an analytical review

This article reviews and analyses new approaches in the sociology of Israel's Palestinian citizens which began to develop in the early eighties. After comparing their common basic assumptions and those of more traditional perspectives, the central theoretical controversies between the newer approaches are examined. These controversies are discussed along three analytical axes: 1. the basic factors which explain the emergence and institutionalization of the ethno-national hierarchy (ideological principles and distributive conflicts); 2. the significant social actors in the shaping of majority-minority power relations and the social arenas in which this process takes place (state and civil society); 3. the use of general analytical frameworks which allow comparative research as opposed to the emphasis on the idiosyncrasy of the Israeli case. The article concludes by suggesting some new research topics and perspectives that might shed light on the dynamics of the subordinate status of Palestinian citizens in Israeli social formation.     

Quality of life following parotidectomy for malignant and benign disease

Parotidectomy is performed for benign or malignant tumors and for selected benign inflammatory and autoimmune conditions. Possible associated complications include facial nerve paralysis, pain, loss of sensation, gustatory sweating, and facial scarring. Global quality of life in patients undergoing parotidectomy has not been reported. The implications of facial surgery with the catastrophic potential of facial nerve paralysis may severely affect quality of life. A quality-of-life study was conducted in patients undergoing parotidectomy for benign and malignant diseases to define the significance of associated morbidity and its impact on quality of life. A quality-of-life instrument was specifically created, based on the principles of the University of Washington Quality of Life questionnaire, and mailed to the patients. Questions addressed recognized complications of parotidectomy. Patient group results were compared for age above and below 45 years, sex, benign versus malignant disease, presence or absence of Frey syndrome, and presence or absence of benign pleomorphic adenoma. Forty-six percent of 125 patients meeting the study criteria fully replied to the questionnaire. The global health score was 3.5, corresponding with "good" to "very good." Except for local sensation, which had a score of 50, all other domains scored above 76. Change in appearance, gustatory sweating, and pain were reported by 70 percent, 57 percent, and 30 percent, respectively. Importance attributed to all domains except facial function was low. Pain was encountered significantly less in patients younger than 45 years of age, and scores for appearance were also highly significant in this age group. Postoperative sequelae were noted in the majority of patients. The dominant sequelae were altered sensation, change in appearance, Frey syndrome, and pain. A degree of permanent postoperative facial nerve impairment was reported by 10 patients. Nevertheless, overall, parotidectomy does not seem to severely affect quality of life.     

Enrichment of a Microbial Culture Capable of Reductive Debromination of the Flame Retardant Tetrabromobisphenol-A, and Identification of the Intermediate Metabolites Produced in the Process

Tetrabromobisphenol-A is a reactive flame retardant used in the production of many plastic polymers. In previous research, it was demonstrated that anaerobic microorganisms from contaminated sediment debrominate tetrabromobisphenol-A to bisphenol-A, but an enrichment culture was not established. The current study was carried out to identify the intermediate metabolites in this process and to determine the factors facilitating enrichment of debrominating microorganisms. During the enrichment process in an anaerobic semi-continuous batch reactor, tetrabromobisphenol-A debromination gradually slowed down with concurrent accumulation of three intermediate products. These compounds were tentatively identified using GC-MS as tri-, di-, and mono-brominated bisphenol-A. GC-MS and HPLC analyses showed one dominant metabolite of dibromobisphenol-A, and NMR analysis identified it as 2,2'-dibromobisphenol-A. Addition of sterile sediment(15% wt/wt) to the reactor stimulated debromination of tetrabromobisphenol-A.Furthermore, different solid amendments such as surface soil and pulverized gray chalk from the site subsurface (100 m below ground) were also stimulating agents.We conclude that organic matter is involved in stimulation since the stimulationeffect of the sediment, soil and gray chalk was abolished after it was heat-treatedto 550 °C. Our study suggests that the debrominating culture requires someorganic components found in the sediment, soil, and chalk in order to sustain activityand perhaps to survive. The possible mechanisms of stimulation by these solids arediscussed.