The compound eye in the opaque-eye phenotype of Drosophilia melanogaster.

The compound eye of the opaque-eye mutant of Drosophila melanogaster was investigated by means of electron microscopy to determine the morphological and physical properties of ommatidial elements. These elements in the mutant were found to differ from those of the wild-type flies in the following ways: (1) The cuticular lens was thinner than that of the control and lacked the typical lamellar construction. (2) The Semper cells were irregular in shape and contained many membranous inclusions similar to those found in degenerating cells; also their nuclei contained virus-like particles. (3) The primary pigment cells contained an abundance of drosopterin-containing granules which were lacking in those of wild-type flies. (4) The superior and inferior central photoreceptor cells were misplaced and their rhabdomeres evidenced some degeneration. (5) The secondary pigment cells had only one type of pigment granules instead of the three types found in the control. These morphological changes in ommatidial elements induced physical abnormalities such as the apparent opaqueness of the eye, the lack of a pseudopupil, the probable disability of the photoreceptor cells to respond to light and the inability of the dioptric system to produce utilizable geometric images.     

Cyclic adenosine 3':5'-monophosphate levels in normal and transformed cells of higher plants

Cyclic adenosine 3′:5′-monophosphate (cAMP) concentrations were determined for various normal and transformed (crown-gall) plant tissues grown in sterile culture. No significant differences in cAMP concentrations were found between normal and transformed cells of $\text{Vinca rosea, Helianthus annuus}$, and $\text{Nicotiana tabacum}$, unlike the suppressed synthesis observed in transformed cells of mammalian systems. cAMP concentrations of these tissues in culture averaged 135 nanomolar. No correlation was found between cAMP concentrations and tissue culture generation times.     

Changes in glycolipid glycosyltransferases and glutamate decarboxylase and their relationship to differentiation in neuroblastoma cells

Glycolipid glycosyltransferase activities involved in the biosynthesis $\text{in vitro}$ of neutral and acidic glycosphingolipids were measured in C-1300 tumors and cloned cells derived therefrom. An adrenergic clone (NIE-115) was grown in tissue culture in the presence of dibutyryl cyclic AMP and the levels of glycosyltransferases were measured before and after differentiation. Increased activities of galactosyltransferases and sialyl-transferases with a concomitant increase in glutamate decarboxylase activity (the enzyme that catalyzes the synthesis of an inhibitory neurotransmitter, γ-aminobutyric acid) were observed.     

Diagnosis of hypothyroidism: a comparison of statistical techniques.

From replies to a postal questionnaire used in a radioactive iodine follow-up scheme patients had to be classified as either "suspected hypothyroid" or "euthyroid." A comparisons has been made of the effectiveness of published statistical techniques in making this classification. Two main conclusions emerged. Firstly, all except one of the methods identified an acceptable proportion of the hypothyroid patients, and, secondly, the results given by these methods were remarkably similar. Thus the simplest, which required only a count of the number of symptoms present, was selected for use.     

Fixation of Dormant Tilletia Teliospores for thin Sectioning

Dormant Tilletia caries teliospores in fixative solution or distilled water were frozen onto specimen chucks of an FTS Sorvall- Christensen frozen thin sectioner and cut or fractured at various temperatures (-20 C to -75 C) and thickness settings (10, 15, 20, and 25 μm). Cytoplasm of dormant spores was well preserved and organelles were found to differ from those of germinated spores in morphology. This procedure makes it possible to fix adequately dormant spores and thus compare the ultrastructurc and histochemistry of dormant spores with those of germinated spores.     

Secondary-site attachment of coliphage lambda near the thr operon

Phage λ has been integrated at a secondary attachment site near the thr oporon of Escherichia coli. The integration caused a pleiotropic effect since both thrA and thrB enzyme activities were lost. Lysogenic, thr⁺ revertants regained thrA and thrB activities although the enzymes were synthetized constitutively at low levels. Four classes of prophage deletion strains were isolated with deletions extending into trpR and the thr operon. Genetic and biochemical analyses indicated a gene order: trpR .. λ .. thrA .. B .. C. Defective transducing phage carrying thr A, B,C were also isolated.     

Differential reactivity of the red-and far-red-absorbing forms of phytochrome to [14C] N-ethyl maleimide

Summary The red-absorbing form (P _r ) and the far-red absorbing form (P _fr ) of undergraded, high-molecular-weight phytochrome from rye (Secale cereale L.) seedlings were examined for their reactivity toward N-ethyl-[¹⁴C]maleimide ([¹⁴C]-NEM). After pre-treatment of P _r with cold NEM and extensive dialysis, photoconversion to P _fr and treatment with [¹⁴C]NEM resulted in an approximately 70% increase in incorporation of radioactivity over the dark control. These results are discussed in relation to the view that phytochrome undergoes a protein conformational change upon phototransformation.     

Structure of cephalic abnormalities in Drosophila melanogaster (Diptera: Drosophilidae)

Scanning and transmission electron microscopy were utilized in studying the cephalic abnormalities of the tu-h strain of Drosophila melanogaster. Abnormalities, appearing as protuberances (growths) of different shapes and sizes, were observed only on or in close proximity to receptor cites. Compound eyes of some flies, besides having such protuberances, either had modified corneal lenses or were absent altogether. Cuticles of the growths were thinner than that of the normal surrounding layer. The epidermal cells associated with setae on the growths or underlying modified corneal lenses remained undifferntiated. Both setae and growths lacked innervation. The receptor portions (retinular sensory cells and secondary pigment cells) of the abnormal compound eye, where the dioptric portions were replaced by protuberances or remained undifferentiated, were unaffected by the mutation. Nuclei of several cells, including oenocytes and fat bodies, close to or underlying epidermal cells of abnormalities, were large and contained compact nucleoli without nucleonemas. Viruslike particles were observed in several nuclei of growth cells. It was concluded from the present study that the alterations induced by the mutation can be only a localized phenomenon restricted to at least several cephalic epidermal cells and/or their derivatives.