Blood osmolality shift in juvenile red drum, Sciaenops ocellatus L. exposed to fresh water

Juvenile red drum, Sciaenops ocellatus , measuring 40–49 mm s.l. tolerated abrupt transfer from 28%osalinity sea water to fresh water (< l%o). A significant shift in blood osmolality from a level of about 350 mosmol l⁻¹ in sea water to a new level of about 311 mosmol l⁻¹ was experienced by fish after 48 h in fresh water. The shift was followed by a slight reduction in blood osmolality to a sustained level of 300 mosmol l⁻¹ after 96 h exposure to fresh water. The overall effect of increased environmental calcium on blood osmotic pressure of young red drum was not significant at the level tested.     

Uganda kob (Adenota kob thomast): Territoriality and the Spatial Distributions of Sexual and Agonistic Behaviors at a Territorial Ground4

Possible functions of territorial behavior were evaluated on the basis of observations of agonistic and reproductive activities of Uganda kob at a “territorial ground” (TG) in southwestern Uganda. We have found that male residents of a TG tend to occupy exclusive areas, and that agonistic interactions are concentrated along the boundaries separating adjacent occupied areas. Thus, we conclude that male kob do engage in the active defense of spatially exclusive territories at a TG.     

Isolation and characterization of the DNA fraction of rat liver chromatin which binds polylysine.

The structure of eukaryotic chromatin has been investigated by isolating and analyzing the "accessible" DNA fraction of rat liver chromatin. This DNA fraction has been isolated by titrating the chromatin with the protese-resistant D isomer of polylysine to bind the "accessible" DNA sites. After removal of chromosomal proteins by digestion with pronase, all DNA not protected from attack by bound polylysine was removed by digestion with DNase. Even after exhaustive treatment with pronase and DNase approximately 30% of the chromatin DNA remains resistant to nuclease attack. Analysis of the isolated DNA shows it to be mainly double-stranded with an average size of 200-250 base pairs. The DNA is slightly A-T rich and contains both repetitive and "single-copy" nuleotide sequences. The results suggest that there are extensive regions in chromatin where the DNA is not tightly complexed with protein. Furthermore, the DNA of these regions is similar in gross properties to the DNA of the total genome.     

Biosynthetic pathway of ribothymidine in B. subtilis and M. lysodeikticus involving different coenzymes for transfer RNA and ribosomal RNA.

Ribothymidine (m5u) in tRNAs of M. lysodeikticus is not derived from methionine. The results indicate that as in tRNAs of B. subtilis a tetrahydrofolate derivative is involved in the formation of m5U, whereas methionine serves as precursor in the biosynthesis of m7G, m1A and m6A. Ribothymidine also occurs in 23S rRNA of B. subtilis and M. lysodeikticus. Approximately 2-3 moles of m5U residues were found per mole of 23S rRNA. In contrast to m5U residues present in tRNAs of B. subtilis and M. lysodeikticus, ribothymidine in 23S rRNA of these organisms and of E. coli is synthesized via S-adenosylmethionine. m6A and m1G, present in E. coli rRNAs, were not detected in rRNAs of (methyl-14C) methionine labeled B. subtilis and M. lysodeikticus.     

Relation of Macromolecular Synthesis in Streptococci to Efficiency of Transformation by Markers of Homospecific and Heterospecific Origin

In previous studies with Streptococcus sanguis and S. pneumoniae as recipients and donors of transforming deoxyribonucleic acid (DNA), it was found that heating recipients just prior to exposure to DNA caused an increase in the number of transformants induced by heterospecific DNA relative to that induced by homospecific DNA. In the present studies, S. sanguis recipients were found to recover from this effect of heat (48 C, 15 min) when incubated at 37 C before exposure to DNA. Inhibitors of nucleic acid synthesis, such as rifampin, 5-fluorodeoxyuridine, actinomycin, and p-hydroxyphenylazo-uracil, but not inhibitors of protein synthesis, such as chloramphenicol and erythromycin, prevented recovery from the effect of heat. Inhibitors of nucleic acid synthesis caused changes in unheated cells similar to those observed with heat treatment; these changes included increased transformability by genetically hybrid DNA and by low-efficiency markers in homospecific DNA. The effect of a combination of heat and inhibitors on transformation by heterospecific DNA was greater than when single treatments were used. The most effective inhibitor used alone was rifampin: in treated recipient cells, the yield of transformants produced by a given amount of irreversibly bound heterospecific DNA was increased without a significant change in the yield of transformants produced by bound homospecific DNA. A cell being doubly transformed by homospecific and heterospecific DNA was enhanced specifically in its transformability with the latter as a consequence of rifampin treatment. Treatment with rifampin also increased co-transformation by linked heterospecific markers. The period during which recipient cells were sensitive to the effects induced by rifampin and fluorodeoxyuridine lasted from 10 to 20 min after DNA uptake.     

Lichtbedingte Orientierungen der Chlorophyllmoleküle in Algenchloroplasten

Der Mesotaenium-Chloroplast hat in Kantenstellung ein Extinktionsmaximum bei λ = 670 nm, in Flächenstellung ein solches bei λ = 680 nm. Chi 660 und 680 sind im Mesotaenium- und im Mougeotia-Chloroplasten parallel zur Thylakoidfläche orientiert. Das gleiche gilt für das Chl 670 des Mougeotia-Chloroplasten, während dieses Chlorophyll im Mesotaenium-Chloroplasten teils flächenparallel und teils flächennormal ausgerichtet ist. Das Molekül bzw. die Porphyrinebene des flächenparallel ausgerichteten Chlorophylls kann mit seinem Rotübergang (Elektronenoscillator für die Absorption roten Lichtes) bzw. mit seinem Blauübergang zusätzlich parallel zur Chloroplastenlängsachse orientiert sein. Die Ausrichtung der Chlorophyllmoleküle steigert sich mit der Lichtintensität, wird jedoch durch DCMU bzw. durch 4-Amino-6-isopropyl-3-thiomethyl-1,2,4-triazin-5-on gehemmt bzw. völlig unterbunden. Herrn Prof. Dr. G. Schulz , Fachbereich Physik der Universität des Saarlandes, danken wir für die Unterstützung bei der Durchführung statistischer Teste, den Farbenfabriken Bayer, Leverkusen, für die Überlassung des 1,2,4-Triazinons.     

Deoxyribonucleic Acid Replication in Simian Virus 40-Infected Cells: III. Comparison of Simian Virus 40 Lytic Infection in Three Different Monkey Kidney Cell Lines

A comparative study of simian virus 40 (SV40) lytic infection in three different monkey cell lines is described. The results demonstrate that viral deoxyribonucleic acid (DNA) synthesis and infectious virus production begin some 10 to 20 hr earlier in CV-1 cells and primary African green monkey kidney (AGMK) cells than in BSC-1 cells. Induction of cellular DNA synthesis by SV40 was observed in CV-1 and AGMK cells but not with BSC-1 cells. Excision of large molecular weight cellular DNA to smaller fragments was easily detectable late in infection of AGMK cells. Little or no excision was observed at comparable times after infection of CV-1 and BSC-1 cells. The different kinds of responses of these three monkey cell lines during SV40 lytic infection suggest the involvement of cellular functions in the virus-directed induction of cellular DNA synthesis and the excision of this DNA from the genome.     

Zur Formalgenetik der Phosphoglucoseisomerase (EC: 5.3.1.9)

Zusammenfassung Es werden Befunde aus einer Sippe mit PGI-Defizienz mitgeteilt. Die beiden Patienten haben eine nichtsphärocytäre hämolytische Anämie, sie besitzen den homozygoten Phänotypus PGI9. Die Eltern sind heterozygot PGI 9-1. Der Zymogrammvergleich von Eltern und Kindern spricht für die Hypothese, daß die PGI ein dimeres Molekül sei, das normalerweise aus identischen Polypeptidketten aufgebaut ist.

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Formal genetics of phosphoglucoseisomerase investigations of a family with PGI-Deficiency

Summary In a family two children exhibited a non-sphaerocytic hemolytic anemia; they revealed the homozygous phenotype PGI9. The parents are heterozygous PGI 9-1. The comparison of the zymogram pattern of both parents and children allows the conclusion that the PGI molecule is a dimer which has identical subunits in homozygous individuals.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Baboon Virus Isolate M-7 with Properties Similar to Feline Virus RD-114

A virus (M-7) isolated from baboon placental tissue demonstrates many similarities to endogenous feline virus RD-114. Immunodiffusion analysis shows a group-specific antigen (gs-1) line of identity between M-7 and RD-114. Anti-RD-114 DNA polymerase IgG inhibits M-7 polymerase by 57% compared to 97% for RD-114. M-7 virus has helper activity as demonstrated by rescue of murine sarcoma virus (MSV) from sarcoma-positive leukemia-negative human amnion cells. The host range of the rescued M-7 pseudotype of MSV, MSV (M-7), is similar to that of RD-114 virus. MSV (M-7) is also able to transform baboon cells and causes no detectable transformation of feline cells without addition of helper feline leukemia virus. Interference properties of M-7 and RD-114 virus are identical. Virus-specific neutralizing antisera, although partially cross-reacting, can distinguish MSV (M-7) from MSV (RD-114). These similarities and differences between RD-114 and M-7 viruses are best explained as type-specific differences between two viruses within the same strain.     

Six medical students in a community hospital

This paper describes part of an education experiment at the University of British Columbia at Vancouver.Six final-year medical students spent approximately 12 weeks in a community. Their time was divided between the hospital and various doctors'' offices. They answered a simple questionnaire to describe their experiences and commented favourably upon the opportunities for direct patient contact, learning basic skills, informal teaching by both family physicians and consultants, and the variety of work available.They had the opportunity to follow up the progress of the patient and learn the natural history of common illnesses. They achieved their basic objectives. We conclude from their reports and informal conversation that the experiment was successful and recommend other institutions to try similar programs.