Biology of budding bacteria

Summary Budding bacteria from aquatic or terrestrial habitats were found to accumulate ferric oxide hydrate (ferric hydroxide) on their cell surfaces. Metal paper clips served as the source of oxidizable iron. Pure cultures deposited ferric hydroxide during growth on sea water medium at a pH of 7.8, but not in a mineral salts medium of normal ionic strength, of pH 7.2, and without NaCl, although some active strains came from fresh water or soil.Ferric iron deposition was found to be initiated at primary active sites on the cell surface; the hyphae and rods eventually become completely encased by the heavy coat.The presence of iron depositing, budding bacteria in fresh water, brackish water or sea water indicates an ubiquitous distribution of these microorganisms.Actively depositing isolates from marine environments are more closely related to Pedomicrobium than to Hyphomicrobium spp. because of their multiple formation of hyphae from rod-shaped swarmer cells. A taxonomic and cultural study of these new forms is in progress.     

Immunocytochemical Quantification of Tyrosine Hydroxylase at a Cellular Level in the Mesencephalon of Control Subjects and Patients with Parkinson's and Alzheimer's Disease

Abstract: Parkinson's disease is characterized by massive degeneration of the melanized dopaminergic neurons in the substantia nigra. The functional capacity of the surviving nigral neurons is affected, as indicated by the subnormal levels of tyrosine hydroxylase (TH) mRNA in these neurons and the presence in the parkinsonian mesencephalon of melanized neurons lacking TH immunoreactivity. This is apparently in contradiction with the known overactivity of dopamine synthesis and release that occurs in the remaining dopaminergic terminals. To test the ability of the surviving neurons to express TH protein, a semiquantitative immunocytochemical method was developed. The relative amounts of TH were estimated with a computer-assisted image analysis system in the dopaminergic neurons of representative mesencephalic sections of control and parkinsonian brains and for comparison in brains from patients with Alzheimer's disease. In control brains, the mean TH content per neuron differed from one subject to another and between the different dopaminergic cell groups of the mesencephalon in the same subject. Within a given dopaminergic region, the level of TH was variable among neurons. In patients with Parkinson's disease, the ratio of TH protein content per neuron in the substantia nigra by reference to that of the central gray substance was reduced. In patients with Alzheimer's disease, the amount of TH was selectively reduced in the remaining dopaminergic neurons of the ventral tegmental area, a region characterized by a loss in dopaminergic neurons. The decrease in cellular TH content might therefore be related to the presence of the neurodegenerative process in the area considered. In patients with Parkinson's disease, the incapacity of the surviving neurons to express normal TH levels may reduce the efficiency of the hyperactivity mechanisms that develop in the remaining striatal dopaminergic terminals.     

Trace metal modification of immunocompetence. I. Effect of trace metals in the cultures on in vitro transformation of B lymphocytes.

Lymphocytes obtained from the spleen of Balb/C mice have been subjected to transformation by LPS in the presence of varying concentrations of Pb²⁺, Cd²⁺, or Cr³⁺. Both DNA and protein turnover were followed. It was found that Pb²⁺ and Cr³⁺ are mitogenic over a broad range of concentrations, while Cd²⁺ is slightly mitogenic at very low (10^?6M) concentration and rapidly becomes inhibitory of both [³H]TdR and [³H]ALA uptake. Pb²⁺ appears to stimulate the action of LPS, while Cr³⁺ appears to inhibit. Each of the metals protects the lymphocytes from cell death arising from incubation with LPS. The mechanism of the observed changes is as yet obscure.     

Biogenesis of the yeast vacuole (lysosome). Proteinase yscB contributes molecularly and kinetically to vacuolar hydrolase-precursor maturation.

The vacuolar proteinase yscB (PrB) has been implicated in the final maturation of procarboxypeptidase yscY (pro-CpY) to the mature wild-type form CpYb of 61 kDa. In PrB-deficient mutants, only the proteinase yscA processed form CpYa of 62 kDa is found [Mechler, B., Müller, H. & Wolf, D. H. (1987) EMBO J. 6, 2157-2163]. We report now that, akin to CpY, two forms of mature proteinase yscA (PrA) can be distinguished. In PrB-deficient mutant cells, PrAa, migrating at about 43 kDa in SDS/PAGE, is found, whereas PrAb, found in wild-type cells, had the known molecular mass of 42 kDa. In the PrB-deficient strain, pro-PrA and pro-CpY matured only to the higher-molecular-mass forms, PrAa and CpYa, and the maturation of both precursors was slower than in the isogenic wild-type strain. Pulse-labeling experiments indicated that the mature forms, PrAb or CpYb, are generated directly in the PrB-containing wild-type strain in vivo. In vitro experiments showed that PrB is able to trigger maturation of its 42-kDa pro-PrB precursor to mature PrB in the absence of PrA. Mature PrB and its proteolytic activity, however, shows a higher stability in the presence of mature PrA. The data indicate a molecular and kinetic participation of proteinase yscB in vacuolar hydrolase precursor maturation.     

Discrimination and consistency of five myosin ATPase stains in human normal and duchenne dystrophic muscle

Summary Limitations in the ability of the human visual system to assess accurately the relative staining densities of individual fibers in muscle tissue stained for myosin ATPase can complicate the objective evaluation of fiber type populations. In this study a novel approach is employed which utilizes human visual capabilities to provide accurate fiber classification. Using this approach, the ability of five ATPase staining techniques to discriminate fiber type categories in single samples of human normal and Duchenne dystrophic skeletal muscle is evaluated, as is the consistency of the fiber type classifications between stains. While no major discrepancies in fiber typing were observed in the sample of normal muscle, significant differences in classification, along with a decrease in the ability to discriminate fiber types were noted in the sample of Duchenne muscular dystrophy. For the most part, these discrepancies were resolved by a re-interpretation of the staining characteristics of fibers in one stain.This work was supported in part by NIH grant NS 15584, and by a grant from the Muscular Dystrophy Association     

Host modification of Sindbis virus sialic acid content influences alternative complement pathway activation and virus clearance

Previous studies have shown that Sindbis virus, an enveloped alphavirus of the togavirus group, activates the alternative complement pathway in the absence of detectable antiviral immunoglobulin. The present studies examined the role of the host-determined sialic acid content of Sindbis virus on activation of the alternative complement pathway. Purified Sindbis virus grown in baby hamster kidney (BHK-SV) and in mosquito (MOSQ-SV) cells yielded virus with 10.2 and less than 2.0 nmol sialic acid/mg viral protein, respectively. Sindbis virus deficient in sialic acid (2.0 nmol sialic/mg) was also produced by treating the BHK-SV with neuraminidase (NANase-SV). When MOSQ-SV or NANase-SV was incubated in either C4DGPS or C2DHS, each consumed significantly more C3 than did BHK-SV, indicating that the ability of Sindbis virus to activate the alternative pathway is inversely related to its sialic acid content. Studies in vivo showed that virus deficient in sialic acid (MOSQ-SV) was cleared from the blood of mice much more efficiently than was virus rich in sialic acid (BHK-SV), after i.v. inoculation. Furthermore, when animals were depleted of C3 through C9 by cobra venom factor (CoVF) treatment, no differences in the clearance of high and low sialic acid-containing viruses were observed. Thus both the activation in vitro and complement-dependent clearance in vivo are significantly affected by the host-determined sialic acid content of Sindbis virus.     

Properties of the foot inhibitor from hydra

Summary A substance was isolated from crude extracts of hydra that inhibits foot regeneration. This substance, the foot inhibitor, has a molecular weight of 500 daltons. It is a hydrophilic molecule, slightly basic in character and it has no peptide bonds. The pruified substance acts specifically and at concentrations lower than 10^–7 M. At this low concentration only foot and not head regeneration is inhibited. Hydra are sensitive to purified foot inhibitor between the second and eight hour after initiation of foot regeneration by cutting. In normal animals the foot inhibitor is most likely produced by nerve cells. A substance with similar biological and physico-chemical properties is found in other coelenterates.     

A new species of Eugenia (Myrtaceae) from Venezuela

Eugenia mcvaughii is described from a forest remnant of the Jardin Botánico of Caracas, Venezuela. Found also in the hills adjacent to Caracas, it may be considered as an endemic species of the Interior Coastal Cordillera.