Surface Antigens of Smooth Brucellae

Surface antigens of smooth brucellae were extracted by ether-water, phenol-water, trichloroacetic acid, and saline and examined by immunoelectrophoresis and gel diffusion with antisera from infected and immunized rabbits. Ether-water extracts of Brucella melitensis contained a lipopolysaccharide protein component, which was specific for the surface of smooth brucellae and was correlated with the M agglutinogen of Wilson and Miles, a polysaccharide protein component devoid of lipid which was not restricted to the surface of smooth brucellae and was not correlated with the smooth agglutinogen (component 1), and several protein components which were associated with internal antigens of rough and smooth brucellae. Immunoelectrophoretic analysis of ether-water extracts of B. abortus revealed only two components, a lipopolysaccharide protein component, which was correlated with the A agglutinogen, and component 1. Component 1 from B. melitensis and B. abortus showed identity in gel diffusion tests, whereas component M from B. melitensis and component A from B. abortus showed partial identity with unabsorbed antisera and no cross-reactions with monospecific sera. Attempts to prepare monospecific sera directly by immunization of rabbits with cell walls or ether-water extracts were unsuccessful. Absorption of antisera with heavy fraction of ether-water extracts did not always result in monospecific sera. It was concluded (as has been described before) that the A and M antigens are present on a single antigenic complex, in different proportions depending upon the species and biotype, and that this component is a lipopolysaccharide protein complex of high molecular weight that diffuses poorly through agar gel. Components 1, A, and M were also demonstrated in trichloroacetic acid and phenol-water extracts. With all extracts, B. melitensis antigen showed greater diffusibility in agar than B. abortus antigens. After mild acid hydrolysis, B. abortus ether-water extract was able to diffuse more readily.     

Antigenic relationships between Aracoccidioides loboi and other pathogenic fungi determined by immunofluorescence

Summary The fluorescent antibody technique was used to study antigenic relationships betweenParacoccidioides loboi and other pathogenic fungi. The findings suggest thatP. loboi is more closely related antigenically to certainP. brasiliensis strains than to others and that it has antigens in common with the yeast form ofHistoplasma capsulatum, H. duboisii, Blastomyces dermatitidis, Candida albicans and also the mycelial form ofCoccidioides immitis. Serum globulins from 3 cases of keloidal blastomycosis were labelled with fluorescein isothiocyanate. These conjugates showed slight or no reactivity withP. loboi, the yeast forms ofP. brasiliensis, H. capsulatum, H. duboisii andB. dermatitidis, However, they stained brightlyC. albicans, serotypes A and B, the tissue form ofC. immitis and the yeast form ofSporotrichum schenckii. Adsorption of these reagents withC. albicans eliminated all staining except that forS. schenckii. These patients had no history of clinical sporotrichosis.Deceased. Last address: Fundacão Gonçalo Moniz, Salvador, Bahia, Brazil. Requests for reprints should be sent to Dr.William Kaplan.Dr.Miranda is in private practice in Rio de Janeiro, Brazil.     

An electron microscopic study of the cerebral blood vessels of the opossum

Summary Blood vessels of the opossum brain are paired, artery and vein, and end in a closed loop. Both anatomically and physiologically they are true end-arteries. The two limbs are enclosed within a single basement membrane and are separated from each other by an intercapillary cell thought to be analogous to the usual capillary pericytes. The similarity of this vascular arrangement to that in the rabbit placenta and in the medulla of the kidney is discussed in relation to the counter-current multiplier system.This work was supported in part by the Beaumont-May Institute of Neurology and by a grant, B-425, from the United States Public Health Service.Research Fellow of the National Multiple Sclerosis Society.     

SDSE: A software package to simulate the evolution of a pair of DNA sequences

An algorithm to simulate DNA sequence evolution under a generalstochastic model, including as particular cases all the previouslyused schemes of nucleotide substitution, is described. The simulationis carried out on finite, variable length, DNA sequences througha strict stochastic process, according to the particular substitutionrates imposed by each scheme. Five FORTRAN programs, runningon an IBM PC and compatibles, carry out all the tasks neededfor the simulation. They are menu driven and interfaced to thesystem through a principal menu. All sequence data files usedand generated by the SDSE package conform to the standard GenBankdatabase format, thus allowing the use of any sequence retrievedfrom this databank, as well as the application of other packagesto analyse, manipulate or retrieve simulated sequences. Received on August 23, 1988; accepted on November 15, 1988     

Cessation of neutrophil influx in C5a-induced acute experimental arthritis is associated with loss of chemoattractant activity from the joint space

Neutrophil emigration is a critical component of the inflammatory process and is generally thought to play a role in host defense as well as in the tissue injury that often accompanies inflammation. Most inflammatory reactions exhibit a sequence of emigrating cell types, thus clearly demonstrating that the neutrophil influx eventually ceases and that the neutrophils are then removed from the lesion. It has been our premise that in order to understand the processes that lead to the progressive inflammatory reactions that underly so many disease processes, it is important to determine the mechanism by which the "normal" inflammatory response resolves. The purpose of this study was to identify the time of cessation of neutrophil influx in experimental arthritis induced by the injection of C5 fragments (C5f) and to investigate mechanisms underlying the cessation process. The migration of i.v. delivery pulses to inflamed joints was assessed by lavage of the joint space and by external scintigraphy. We found no evidence for the development of inhibitory systems against chemotactic factors or "desensitization" of the inflamed site, because a second injection of C5f into joints which had been injected previously with C5f resulted in enhancement rather than inhibition of migration. Neither was evidence found for altered tissue barriers to migration or for desensitization of neutrophils as possible explanations for cessation of influx. The major mechanism appeared to be a loss of chemoattractant activity in the joint space between 2 h and 6 h after C5f injection which was detected by transfer into a fresh joint. Radiolabeled C5a des-Arg had a t1/2 of disappearance from the joint of less than 1 h, which suggested that the transferred chemoattractant must, in part, have been due to the generation of new chemotaxins by C5f injection. These observations suggest that continued generation of chemoattractants or failure of their subsequent removal may be mechanisms leading to persistent neutrophil influx in chronic inflammation.     

The levels of ζ, γ, and δ chains in patients with Hb H disease

Summary Details are given of a study of blood samples from 24 patients with Hb H disease from different Mediterranean countries and from the Far East. Four different types of -thal-1 (--) were observed, namely-() ( 20.5-kb deletion);--MED-I ( 17.5-kb deletion);--MED-II (>26.5-kb deletion); and--SEA ( 18-kb deletion, in Orientals only). The -thal-2 was mainly of the deletion type (16 with the 3.7-kb deletion; 1 with the 4.2-kb deletion), while 4 of the 7 patients with a nondeletional type had the five-nucleotide deletion at the donor splice site of the first intron of the 2 gene. All patients had a mild-to-moderate hemolytic anemia; no significant differences in hematology were observed between the groups. Hb A₂ was decreased to about one-third of the normal level. The Hb H formation varied considerably and its quantitation was not always satisfactory. Patients with Hb H disease due to any -thal-1 combined with a nondeletional -thal-2 had the highest Hb H levels and a more marked anemia. The chain production was small and absent in patients with the MED-II type of -thal-1 because this deletion included the and genes. The highest chain levels were present in the four patients with the SEA type of -thal-1. The chain production was increased, particularly in patients with a mutation of C T at position-158 to the ^G globin gene. This chain was primarily present as Hb Bart's (or ₄) and only about 15% was recovered as Hb F or ₂₂. The evaluation of the rate of chains produced in these patients was greatly facilitated by data from one patient who had Hb H disease and a heterozygosity for the ^A-⁺. The low levels of Hb A₂ and of Hb F (relative to Hb Bart's) can be explained by a decreased affinity of chains for and chains as compared with chains in conditions of severe chain deficiency.     

Evaluation of a method to measure conjugal transfer of recombinant DNA in soil slurries

Release of recombinant microbes into the environment necessitates an evaluation of their ability to transfer genetic material. The present report evaluates a method to detect conjugal DNA plasmid transfer in soil slurries under various environmental conditions. DonorPseudomonas cepacia containing pR388::Tn1721 andP. cepacia recipient cultures were coincubated in soil slurries containing autoclaved or natural soil and treated with one or more of 14 experimental conditions. Conjugal mating frequency (transconjugants per initial donor) ranged from 4.8×10^–1 to 1.9×10^–7. Highest numbers of transconjugants, 1.5×10⁷ colony forming units/ml soil slurry, were observed following incubation at 35°C with an enriched nutrient supplement added to the soil. Low numbers of transconjugants, 10³ colony forming units/ml soil slurry, were observed when mating pairs were subjected to low nutrient or pH stress even though initial donor and recipient populations were maintained at high levels. This test system provides a simple way to estimate effects of changing environmental factors on plasmid transfer rates and on the survival of recombinant microorganisms. By use of soil collected from sites proposed to receive genetically engineered microorganisms, preliminary risk assessments can be obtained regarding the potential for gene transfer and microorganism survival with this soil slurry test system.     

Dopamine-1-mediated stimulation of phospholipase C activity in rat renal cortical membranes

Phospholipase C (PL-C) mediates transduction of neurotransmitter signals across membranes via hydrolysis of phosphatidylinositol-4,5-bisphosphate (PIP2), leading to generation of second messengers inositol-1,4,5-trisphosphate and diacylglycerol. In this study, dopamine-1 (DA-1) but not dopamine-2 (DA-2) agonists were shown to stimulate PL-C activity in renal cortical membranes. The DA-1 agonist, SKF 82526, stimulated the release of inositol phosphates from renal cortical membranes prelabeled with [3H]myoinositol. The majority of the label (75%) was found in phosphatidylinositol followed by PIP2 (15%) and phosphatidylinositol-4-phosphate (10%). A DA-1 specific effect on PL-C activity was also observed in an in vitro assay of PL-C activity in renal cortical membranes and basolateral and brush border membranes using [3H]PIP2 as the substrate. Dopamine and SKF 82526 stimulated the release of inositol phosphates from added [3H]PIP2 in a concentration-dependent manner. This release was blocked by the DA-1 antagonist SCH 23390 but not by the alpha-adrenergic antagonists phentolamine and prazosin. In contrast, the DA-2 agonist LY 171555 had no effect on inositol phosphate release. Guanosine 5'-(3-O-thio)triphosphate enhanced while guanyl-5'-yl thiophosphate attenuated the DA-1 agonist-stimulated PL-C activity. PL-C activity as measured by [3H]PIP2 hydrolysis had a pH optimum of 6.5, was inhibited by Mg2+ concentrations above 1 mM, was linear with time and protein concentration, and was sensitive to phosphatidylserine and calcium concentrations. We conclude that PL-C is activated by DA-1 but not DA-2 agonists in renal cortical membranes as well as both the basolateral and brush border renal tubular membranes. It is speculated that this action may mediate the natriuretic effects of dopamine in renal tubular epithelia.     

Iron nutrition of a hydroponic strawberry culture (Fragaria vesca L.) supplied with different Fe chelates

Several indexes are used to determine the iron nutritional status of plants, but their effectiveness depends either on the plant growth conditions in natural environments or on the assay conditions. This research was conducted to test different indexes of the iron nutritional status of a hydroponic strawberry culture where treatments mainly differed in the source of the iron applied: Fe-EDTA, Fe-EDDHA and Fe-polyflavonoid. Macro and micronutrient concentrations in the nutrient solutions, leaf and vascular tissues were measured. Fe concentration in the nutrient solution during the course of the experiment was considered in relation to the stability of the different chelates. Both Fe concentration and total Fe content of leaves reflected the effect of the treatments; Fe/Mn ratio was significant as a diagnosis index. Other element ratios as P/Fe and K/Ca are not well related with the iron nutrition symptoms observed. Fe²⁺ concentration measured in leaves was not directly affected by the different chelate treatments.