Production of Aseptic Spores of Vesicular-Arbuscular Endophytes and Their Viability After Chemical and Physical Stress

The survival of germinating spores of vesicular-arbuscular endophytes after treatments with oxidizing agents, antibiotics, moist heat, ultrasonic radiation, and ultraviolet radiation was compared with that of their contaminating microbes. Spores of three species were rapidly decontaminated by treatment with 0.42% (wt/vol) chlorine available from 5.0% (wt/vol) chloramine-T at 30°C for 20 to 40 min depending on the species and the soil from which they were extracted. This treatment did not change spore viability. The survival of spores was reduced by exposure for 20 min to 1.11% chlorine at 30°C for Glomus caledonius or at 35°C for Acaulospora laevis. Growth of any bacteria surviving treatment with oxidizing agents was inhibited by 100 μg of chloramphenicol per ml in agar; however, spore germination and germ tube growth were reduced only by concentrations greater than 200 μg/ml in agar. Spore germination was decreased by concentration of pimaracin, which controlled fungal growth. The spores survived moist heat at 40°C for 80 min, 55°C for 10 min, and 60°C for less than 1 min. The viability of spores was unaffected by ultrasonic irradiation for up to 4 min. Spores of G. caledonius and A. laevis were extremely resistant to ultraviolet radiation. Their viability was unaffected by exposure to 5 × 10⁸ ergs cm⁻² from an ultraviolet source of 253.7nm. The spores had very thick, pigmented walls, and the possibility that these provided some protection against the physical and chemical treatments is discussed. The degree of physiological damage to the spores caused by the treatments demonstrated some adverse effects of basic laboratory procedures. This information, together with that on the comparative sensitivity of contaminating microbes to the treatments, was used in the development of protocol for producing large numbers of uncontaminated spores.     

Photoreaction center of photosynthetic bacteria. 2. Size and quaternary structure of the photoreaction centers from Rhodospirillum rubrum strain G9 and from Rhodopseudomonas sphaeroides strain 2.4.1.

The photoreaction center from Rhodospirillum rubrum strain G9 binds about 6 times as much sodium dodecyl sulfate as certain proteins commonly used as molecular weight markers for sodium dodecyl sulfate--polyacrylamide gel electrophoresis. This presumably explains the apparent discrepancy between the molecular weight of the photoreaction center determined by electrophoresis (76 000) and its minimal molecular weight (87 000). The molecular weight of the photoreaction center solubilized with Triton X-100 was determined by three different methods: conventional sedimentation equilibrium, a combination of sedimentation velocity and gel filtration measurements, and sedimentation equilibrium in H2O and in D2O. Each technique required a determination of the amount of bound detergent. All three methods gave molecular weight values close to 60 000. A similar molecular weight was found for the photoactive beta gamma dimer obtained from the photoreaction center of Rhodopseudomonas sphaeroides strain 2.4.1 which, as a whole, had a molecular weight of 87 000. These results indicate that the photoreaction center from Rp. sphaeroides is an oligomer of the type alpha 1 beta 1 gamma 1. In contrast, the photoreaction center from Rs. rubrum appears to be dissociated, in solution, into a photoactive beta gamma dimer and a free polypeptide alpha.     

Chronic Hepatitis Associated with Drug Abuse: Significance of Hepatitis B Virus

One hundred and seventy-seven former heroin addicts, consisting of 85 who were newly admitted to a methadone maintenance program and 92 who had received methadone for a mean period of 30 months, were prospectively studied for up to 2 years in order to determine: (1) the effect of heroin withdrawal on the hepatic abnormalities, and (2) the incidence of HBsAg, anti-HBs, and anti-HCc as indices of the frequency of hepatitis B virus infection. Our study indicates that (1) hepatic abnormalities persist when heroin is discontinued and are not temporally related to drug and/or needle usage, and (2) that 71% of subjects had either HBsAg or anti-HBs; anti-HBc was tested for in 16 patients and was present in 100%, although 9 of the 16 were both HBsAg- and anti-HBs-negative. This study suggests that hepatitis B is largely responsible for the liver dysfunction. It is proposed that an abnormality in immune function, induced by heroin, is responsible for the high incidence of chronic hepatitis. Attention is drawn to the similarity between former drug addicts and hemophiliacs, since both develop chronic hepatitis in spite of anti-HBs in the serum.     

Structure-function relationship in hemoproteins: The role of cytochrome c 3 in the reduction of colloidal sulfur by sulfate-reducing bacteria

Cytochromes c ₃ of different strains of sulfatereducing bacteria have been purified and tested for their capacity to reduce colloidal sulfur to hydrogen sulfide. The results are in good agreement with the activities reported for the whole cells. Cytochrome c ₃ is the sulfur reductase of some strains of sulfate-reducing bacteria such as Desulfovibrio desulfuricans Norway 4 and sulfate-reducing bacterium strain 9974 from which the sulfur reductase activity can be purified with the cytochrome c ₃. In contrast, Desulfovibrio vulgaris Hildenborough cytochrome c ₃ is inhibited by the product of the reaction namely hydrogen sulfide. Chloramphenicol has no effect on the sulfur reductase activity of D. desulfuricans Norway 4 when resting cells grown on lactate-sulfate medium are put in the presence of colloidal sulfur. This shows that the sulfur reductase activity is constitutive and corresponds to the fact that colloidal sulfur grown cells do not contain more cytochrome c ₃ (or another sulfur reductase) than lactate-sulfate-grown cells.     

Biochemical research on oogenesis. RNA accumulation during oogenesis of the dogfish Scyliorhinus caniculus

Four biochemical mechanisms have been shown to operate in the oocytes of amphibians and teleosts: (1) amplification of the 28 S and 18 S genes, (2) noncoordinate accumulation of 5 S RNA and 28 S + 18 S RNA, (3) storage of 5 S and transfer RNA made in excess by small oocytes within nucleoprotein particles, (4) expression of different 5 S genes in oocytes and somatic cells. We have tried to extend these observations to another group of vertebrates, i.e., selacians (Chondrichthya). Our data suggest that ribosomal gene amplification is low or absent in the oocytes of the dogfish Scyliorhinus caniculus. However, previtellogenic oocytes of this species accumulate more 5 S RNA than needed for ribosome assembly. Transfer and 5 S RNA present in small oocytes are probably not free in the cell sap. A substantial fraction of these RNAs sediments at 10 S when homogenates of immature ovaries are centrifuged in sucrose density gradients. In contrast to what we observed in amphibians and teleosts, 5 S RNA from ovaries of S. caniculus is identical in sequence to 5 S RNA from liver. Among the four mechanisms mentioned above, the second and probably the third one are used by the oocytes of S. caniculus. Mechanism (4) is absent in this species. No definitive conclusion can be drawn concerning mechanism (1), i.e., ribosomal gene amplification.     

Design and evaluation of head unit for wheelchair control by quadriplegic patients.

A control unit was designed to allow persons who have lost hand and arm function to control the speed, steering, reversal and on-off switching of an electric wheelchair by means of backward movement and rotation of the head. When possible, shoulder movement was used to control both reversal and on-off switching. Clinical evaluation in 10 patients with quadriplegia and 2 with severe neuromuscular disease showed that the unit neither interfered with nor restrained the patients'' residual body movements, permitted use of natural head movements for smooth and fast control of the wheelchair, and was well accepted by and integrated into the life of the patients.     

The fine structure of polychaete septate junctions

Summary Epidermal septate junctions of Nereis sp. and Cirriformia sp. fixed with OsO₄ or glutaraldehyde/OsO₄ display variable structure in electron micrographs. In transverse section the septa are often indistinct and obscured by opaque material that fills the junctional cleft. Septa (spaced at 180–280 Å) are more clearly defined in slightly oblique transverse section; they exhibit an electron lucent center and appear to be linked by arms. En face views of the junction show a honeycomb pattern. Cytoplasmic faces of junctional membranes are backed with plaques opposite the septa. Lanthanum used as a tracer delineates junctional structure in negative contrast. In transverse section a chain-like lattice is present in the junctional cleft. En face views show parallel rows of pleated elements often linked by arms into honeycomb arrays. Oblique sections demonstrate that these pleated elements are continuous with the chain-like lattice seen in transverse sections. Lanthanum does not pass entirely through the junction. Lanthanum reveals that the septa have a very intricate substructure, but it is difficult to visualize the architecture that could generate the various images presented by these junctions when seen in different orientations. However, it is clear that these junctions possess some features that are diagnostic of several supposedly different types of septate junctions in invertebrates.Supported by USPHS grants NIH 5 P01 NS-07512, NIH 2701 GM-00102, and NB-00840, and by a grant from the Pomona College Research CommitteeI thank Sarah Wurzelmann, Stanley Brown, Nancy Kelly, and Gerhard Ott for excellent technical assistance. Portions of this study were carried out while I was a Postdoctoral Fellow in the Department of Anatomy, Albert Einstein College of Medicine. I dedicate this article to Berta Scharrer as a token of appreciation and affection for her guidance, encouragement, inspiration, and example of excellence     

Galactokinase Mutants of Chinese Hamster Somatic Cells Resistant to 2-Deoxygalactose

The growth of Chinese hamster somatic cells was inhibited by 0.2 mg/cc of 2-deoxygalactose. Mutants partially or fully resistant to 2-deoxygalactose were isolated in a single-step or two-step selection. Some of them did not grow as well as the wild type; one of them which lacked galactokinase(EC.2.7.1.6) activity did not grow at all in galactose medium. The galactokinase kinetic properties (Vmax & kmax of the other mutants and of the wild type were different. Therefore resistance resulted either from the possible absence of galactokinase synthesis or from a structural mutation, possible a missence mutation, in the galactokinase gene.- A simple diagnostic test for juvenile cataract is proposed.     

Analysis of multiple basal cell carcinomas (BCCs) arising in one individual highlights genetic tumor heterogeneity and identifies novel driver mutations

Basal cell carcinoma (BCC) is the most common human cancer, especially in individuals with light skin phototypes (i.e., Fitzpatrick I-II skin type). Many affected develop multiple BCCs during their lifetime. It is not uncommon to observe elderly patients with >5 BCCs. In this study, we explored whether for patients diagnosed with multiple BCCs, analyzing the genomic mutations in one tumor could be sufficient to derive meaningful molecular/genetic conclusions regarding the other BCC tumors. Following the Genome Analysis Toolkit (GATK) best practices we have completed the study of 6 BCCs that occurred in an 83-year-old Caucasian male due to sun exposure. We have analyzed exome sequencing data of each BCC tumor and matched normal skin samples. We identified that BCCs from the same patient shared some of the key driver mutations, but they also displayed significant intertumoral heterogeneity. This finding may in part explain the different clinical progression/evolution of BCCs observed in the same patient. This work also highlights the value of characterizing multiple BCCs in one individual to identify patient-specific genetic events with a potential link to other malignancies and implications for personalized medicine.