High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans

We compared male-reproductive-tract polypeptides of Drosophila melanogaster and D. simulans by using two-dimensional gel electrophoresis. Approximately 64% of male-reproductive-tract polypeptides were identical between two randomly chosen isofemale lines from these two species, compared with 83% identity for third-instar imaginal wing-disc polypeptides. Qualitatively similar differences were found between reproductive tracts and imaginal discs when D. sechellia was compared with D. melanogaster and with D. simulans. When genic polymorphism was taken into account, approximately 10% of male- reproductive-tract polypeptides were apparently fixed for different alleles between D. melanogaster and D. simulans; this proportion is the same as that found for soluble enzymes by one-dimensional gel electrophoresis. Strikingly, approximately 20% of male-reproductive- tract polypeptides of either D. melanogaster or D. simulans had no detectable homologue in the other species. We propose that proteins of the Drosophila male reproductive tract may have diverged more extensively between species than have other types of proteins and that much of this divergence may involve large changes in levels of polypeptide expression.      

Steady flow of a viscous fluid through a network of tubes with applications to the human arterial system

The paper presents a finite-element model for the analysis of steady flow of a viscous fluid through a connected system of elastic tubes with the aim of simulating the conditions of blood flow through the human arterial system. The governing equations of the model are non-linear in character and are solved through an iterative computational procedure. This model is capable of incorporating the effects of stenosis on flow and pressure. Typical results are presented and discussed. Quantitative results have been obtained on blood flow through a model of the human arterial system corresponding to the sets of prescribed conditions at the terminations. Also computational results on the effect of stenosis in typical arteries of the system are presented.     

Microelectrode studies of the active Na transport pathway of frog skin

When the outer surface of short-circuited frog skin was penetrated with microelectrodes, stable negative potentials that averaged near -100 mV were recorded consistently, confirming the results of Nagel (W. Nagel. 1975. Abstracts of the 5th International Biophysics Congress, Copenhagen. P-147.). The appearance of these stable potentials, V(O), concurrent with the observations that (a) a high resistance outer barrier R(O) accounting for approximately 75 percent or more of the transcellular resistance of control skins had been penetrated and that (b) 10(-5) M amiloride and reduced [Na] outside caused the values of V(O) to increase towards means value near -130 mV while the values of percent R(O) increased to more than 90 percent. It was of relationships were the same as the values of E(1) observed in studies of the current-voltage relationships were the same as the values of E’(1) defined as the values of voltage at the inner barrier when the V(O) of the outer barrier was reduced to zero by voltage clamping of the skins. Accordingly, these data are interpreted to mean that the values of E(1), approximately 130 mV, represent the E(Na) of the sodium pump at the inner barrier. 2,4-DNP was observed to decrease the values of transepithelial voltage less than E(1) the V(O) was negative. These data can be interpreted with a simple electrical equivalent circuit of the active sodium transport pathway of the frog skin that includes the idea that the outer membrane behaves as an electrical rectifier for ion transport.     

Effect of clay,organic matter and CaCO3 content on zinc adsorption by soils

Summary Zinc adsorption was studied in suspensions of six soils of different physicochemical characteristics in dilute ZnSO₄ solutions. At low concentrations, Zn²⁺ adsorption was described by the Langmuir adsorption equation. The calculated Langmuir adsorption maxima were related positively to clay and carbonate content and negatively with organic matter content of soils. Multiple regression analysis revealed that zinc adsorption maxima can be predicted with good precision from information in soil survey reports. When the added Zn²⁺ exceeded the adsorption maximum, the solid phase of zinc controlling its concentration in solution was either zinc hydroxide or carbonate so long as soil carbonates were present. The values of zinc potential also indicated that soils retain Zn²⁺ more strongly than Zn(OH)₂ or carbonate. Postgraduate student Professor of Soils. Professor of Soils.     

Some measures of reducing leaching loss of nitrates beyond potential rooting zone

Summary Soil nitrate profiles under seven treatments of an experiment on intercropping in row crops were studied at sowing and the after harvesting of different crops. The estimates of NO₃ ^––N in these profiles indicate that intercropping in the row crops grown during the rainy season considerably reduced leaching loss of nitrates. Where the main crop receives the recommended fertilizer amount and the intercrop a small additional application, intercropping greatly reduced the amount of unutilized nitrates and hence their leaching beyong root zone.     

Homozygous tyrosinase gene mutation in an American black with tyrosinase-negative (type IA) oculocutaneous albinism

We have identified a tyrosinase gene mutation in an American black with classic, tyrosinase-negative oculocutaneous albinism. This mutation results in an amino acid substitution (Cys----Arg) at codon 89 of the tyrosinase polypeptide. The proband is homozygous for the substitution, suggesting that this mutation may be frequently associated with tyrosinase-negative oculocutaneous albinism in blacks.     

Blastomycosis: Report of the first case from Alberta,Canada

The first known case of laboratory confirmed blastomycosis in Alberta occurred in 1970. The patient, who is believed never to have left Alberta, presented with of headaches, sore neck and impaired intellect. Initially, tuberculous or cryptococcal meningitis was suspected, but laboratory findings did not support the diagnosis. A fungus resembling Blastomyces dermatitidis was isolated from the venticular cerebrospinal fluid and lung at autopsy. A few yeast cells suggestive of B. dermatitidis were seen in lung and brain tissue sections. Initial attempts at in vitro conversion of the mycelial form of the isolate into yeast form on several enriched media were unsuccessful. The fungus gave ± to ++ reactions with B. dermatitidis specific conjugate by the direct fluorescent antibody technique, it was not pathogenic for mice and guinea pigs, and no asexual spores were produced in slide cultures. Further investigation indicated that the mycelial form of the fungus converted into its yeast form when an actively growing inoculum was used, although the yeast cells varied considerably in size. The yeast form produced disseminated infection in mice within 10 days. Exoantigenic analysis demonstrated an A antigen specific for B. dermatitidis, which revealed the identity of this organism as an atypical strain of B. dermatitidis.

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Zusammenfassung Der erste Fall in Blastomycosis von einem Laboratorium wurde 1970 in Alberta bestätigt. Der Patient — der wahrscheinlich Alberta nie verlassen hat — klagte über Kopfschmerzen, Genickschmerzen und zeigte beeinträchtigte Verstand. Anfänglich wurde TBC — oder cryptococcal meningitis vermutet, laborfunde unterstutzten jedoch nicht die Diagnose. Ein Fungus — ahnlich zum Blastomyces dermatitidis wurde von venticular cerebrospinal Flüssigkeit und von der Lunge nach der Autopsie isoliert. Wenige Hefezellen hinweisend auf B. dermatitidis wurden gewebschnitten von Lunge und Gehirn festgestellt. Anfängliche Versuche die isolierten mycel Form in die Hefe Form in vitro mit Hilfe verschiedener angereicherter Nahrboden was erfolglos. Der Fungus ergab in der Direct Fluorescent Antibody Technik. ± zu ++ Reaktion mit dem B. dermatitidis specifische Konjugate; es war nicht pathogen fur Mause und Meerschweinchen, asexual Sporen wurden in der objecttrage Kultur produziert. Weitere Untersuchungen zeigten, dass sich die mycel Form des Fungus in die Hefeform umwandelte wenn ein gut wachsendes Inoculum gebraucht wurde. Die Hefezellen zeigten jedoch beträchtliche Grossenunterschiede. Die Hefeform verursachte in Mauseneine generallisierte Infektion in inerhalb von 10 Tagen. Exoantigenik Analyse zeigte ein A Antigen, specifisch für B. dermatitidis, welches die Identität des Organismus als atypischen Stamm des B. dermatitidis aufwies.

     

Some measures of reducing leaching loss of nitrates beyond potential rooting zone

Summary Seven sites in two long-term fertility experiments progressing at PAU Farm Ludhiana were selected on the basis of fertilizer treatments they were receiving. Soil samples were obtained upto 225 cm depth at 15 cm interval and nitrate was estimated from them by phenol disulphonic acid method. In the first experiment, to each of the three sites, equal amount of N was applied. When phosphorus and potassium were added at the rate of 26.2 kg P/ha and 24.9 kg K/ha, there was little NO₃ ^--N left in the profile for leaching, and where no P and K was added, lot of NO₃ ^- was left in the profile unutilized. Graphs for P₁₃K₂₅ treatment were in between the two extremes. Perhaps by balanced fertilization roots become proportionately efficient absorbers and little amount of nutrients is left, which is not absorbed. In the second experiment, supply of NPK to all the three treatments was increased or decreased from the recommended dose in a proportionate manner. This resulted in a nitrate distribution pattern similar to that of control treatment where no N was applied and thus strengthened the case for balanced fertilization.     

Electrophoretic analyses of proteins,peroxidases, and phosphatases of single and mated cultures of Arthroderma benhamiae

Zusammenfassung Extrakte 26 Tage alter Kulturen der (+)- und (–),Stämme vonArthroderma benhamiae (UAMH 2822, 2823) und ihre befruchtete Kreuzung (2822 x 2823) wurden mittels der Polyacrylamide-Gel Elektrophorese Methode auf ihre Proteine, Phosphatasen und Peroxidasen untersucht. Sowohl die (+)- wie auch die (–)-Stämme zeigten 8 Proteinbande, aber die mit Gymnothecien gekreuzten Kulturen zeigten nur 6 Bande. Wenn jedoch die Proteinprofile dieser zwei entgegengesetzten Paarungstypen und befruchteten Gymnothecien miteinander verglichen wurden, wurden Unterschiede in der Lage und Färbungsintensität einiger Bande beobachtet. Die säurehaltigen und alkalischen Phosphatasemuster der (+)- und (–)-Stämme waren ziemlich ähnlich, aber unterschieden sich von den Mustern gekreuzter, befruchteter Gymnothecienkulturen. Peroxidase Isozyme wurden in keinen der beiden Paarungstypen oder in den gekreuzten Gymnothecienkulturen entdeckt.