FINE STRUCTURAL STUDIES OF ZEA MAYS POLLEN I: CELL MEMBRANES AND EXINE ONTOGENY

Electron microscopy was used to study pollen wall ontogeny in Zea mays. The initial stage of development consisted of compartmentalization of microspores within callose special walls. Microspore plasma membranes retracted and tubular elements of the endoplasmic reticulum became perpendicularly oriented to the plasma membranes. Evaginations of the endoplasmic reticulum into the microspore plasma membrane resulted in the establishment of a template or blueprint of the mature pollen wall. Sporopollenin deposition upon the template began immediately after dissolution of the callose special walls and release of the microspores into the anther locule. The columellae were the first pollen wall units to be formed; the tectum and foot layer became established shortly thereafter. The granular endexine was the last-formed unit. The relationships of membrane systems to the ontogeny of the pollen wall units and the mode of pollen wall growth are discussed.     

The ultrastructure of Mississippian and Archaic Indian bones from various soil and drainage conditions

Indian bones from Mississippian and Archaic periods were examined by the techniques of electron microscopy and electron diffraction. Specimens of all ages containing intact mineral constituents showed numerous areas in which the apatite crystals exhibited typical periodic banding as seen in hard tissues of recent age. Diffraction patterns from the same areas verified the morphological appearance. Phosphotungstic acid stained, decalcified sections exhibited collagen fibrils with typical periodic banding regardless of age or soil conditions. In specimens of Archiac age there were a greater number of “poorly preserved” areas as compared with bones from Mississipian excavations. In these areas the collagen appeared to be degraded and the apatite crystals were randomly oriented. No attempt to quantitate the age changes was made in view of the inherent limitations of the method of investigation.     

Salivary Excretion of Coxsackie B-1 Virus in Rabbits

Coxsackie B-1 virus was injected into the ear vein of albino doe rabbits. Saliva and blood samples were taken before the injection of virus and at specific times thereafter. Virus was recovered in the whole saliva when the blood titer was approximately 10(4) TCID(50) per 0.1 ml or greater. The virus could be detected in the saliva as early as 2 min after the initiation of the viremia. The recovered virus was shown to be the same as the injected virus by serological identification of the recovered virus with neutralizing antibody for Coxsackie B-1 virus. These results suggest that virus may be transmitted to other animals in the saliva of animals who are in the viremic phase of infection without infection of the oropharyngeal tissues.     

Microorganisms of the Upper Atmosphere: III. Relationship between Altitude and Micropopulation

Simultaneous sampling for microorganisms was accomplished at altitudes of 690, 1,600, and 3,127 meters. The location of temperature inversions in relation to the collection altitude determined, to a great extent, the micropopulation. High micropopulations were found when an inversion was above the sampling altitude, and low populations when the inversion was below the sampling altitude. Diurnal periodicity which could be generally correlated with periods of minimal and maximal convective activity was observed. Evidence is presented showing that the micropopulation is more stable at higher altitudes than at lower altitudes.     

Inhibition of Microbial Lipases by Fatty Acids

Addition of lard or sodium oleate to the medium used for lipase production by Pseudomonas fragi resulted in a decreased accumulation of lipase in the culture supernatant fluid without affecting cell growth. The production and activity of lipase was inhibited by lard, sodium oleate, and the salts of other unsaturated fatty acids. Some divalent cations, Tweens, lecithin, and bovine serum prevented oleate inhibition, but did not reverse it. Similar inhibitory actions were observed with Geotrichum candidum lipase, but not with a staphylococcal lipase or pancreatic lipase. A protective effect by protein in crude enzyme preparations is indicated. The ability of oleate to lower surface tension does not appear to be related to its ability to inhibit lipase.     

Modified Agglutination Test for Pasteurella tularensis

Several modifications in technique were incorporated into the standard agglutination test for Pasteurella tularensis. Reciprocal shaking of all tubes in a Kahn shaker was introduced to increase the rate of agglutination and quantity of agglutinated cell mass, making it possible to report preliminary results within 4 hr. Increased incubation time at a higher temperature was used to favor the rate of agglutination. A serum control for each serum tested was necessary to detect false positive tests. Finally, a verification procedure with 5% NaCl used as the diluent was instituted to prevent these false positive reactions.     

Germination and initial growth of microsporon audouinii from infected hairs

Summary and Conclusion 1. The germinating spores ofMicrosporon audouinii on infected hairs appear to require thiamine, riboflavin and nicotinic acid or its amide for initial growth. They show complete independence for inositol and pyridoxine.2. Components of the arginine-urea cycle and uracil stimulated growth more than other nitrogen sources. Organic nitrogen is more readily utilized than inorganic sources.3. The hexoses glucose, mannose and fructose are the better utilized carbohydrates. Trehalose is more stimulatory for growth than other disaccharides.4. Hydrogen ion optimum for growth is within a narrow range around pH 6.8 for buffered solutions. The optimum range is wider for unbuffered solutions under the conditions tested.5. Optimum temperature for growth lies within a narrow range of the normal variance of room temperature. Growth rate decreases rapidly at either extreme of this range.6. Within the limits of the system tested a positive Eh does not alter the growth rate or incubation time of the organism, but a negative initial redox potential decreases rate of growth and increases incubation time.A preliminary report of this work was presented at the 57th meeting of the Society of American Bacteriologists and was used in a graduate thesis by the senior author at the University of Illinois (24).     

Skin Homografts in Patients with Cancer of the Cervix

Skin homografts were applied to patients with cervical cancer. In 9% (10 of 110) of untreated patients, grafts survived for more than two weeks. The frequency of prolonged graft survival was increased by pelvic surgery or radiotherapy. It was highest, 62% (34 of 55), in those with recurrent cancer. Recurrence and death in patients studied prior to treatment and followed up six months to two and a half years was three times more frequent in those with grafts tolerated over two weeks than in those rejecting them in a shorter period, i.e. five of 10 and 10 of 74, respectively.     

Clinical Evaluation of the Oral Contraceptive Use of Norethindrone 5 mg. plus Mestranol 0.075 mg

Norethindrone 5 mg. plus mestranol 0.075 mg., taken daily from menstrual cycle day five through day 24, was used as an oral contraceptive agent in 1248 cycles by 132 clinic patients. One hundred and one patients used this method for six months or more. There were no unplanned pregnancies. Breakthrough bleeding occurred in 38 cycles (3.0% of all cycles). In 25% of 1201 cycles the duration of menstrual flow was shorter than that which had been considered usual for the individual patient involved, and the most common weight change was a gain of 6 to 10 lb.