ALBERT

Notes: SYNOPSIS Examination of stained specimens (protargol and nigrosinbutanol) of hypotrich ciliates during division allows understanding of morphogenesis of buccal structures and cirri. Midventral, frontal, and transverse cirri in both proter and opisthe of Urostyla marina differentiate from a longitudinal series of numerous oblique ciliary streaks in a manner similar to that of Bakuella, Holosticha, Keronopsii. Pseudourostyla, and Uroleptus. This pattern differs markedly from that in Amphisiella, Kahliella, Paraholosticha, and Paraurostyla, in which the fronto-ventral and transverse cirri arise from a series of fewer (2–5) ciliary streaks in a longitudinal or fan-like array. Rows of marginal cirri in U. marina arise independently, as in Urostyla grandis. On the basis of comparisons of both structural and morphogenetic features of this and other hypotrichs, the family Urostylidae is redefined to contain Urostyla (type), Bakuella, Holosticha, Keronopsis, Pseudourostyla, and Uroleptus. Other genera formerly contained in the families Holostichidae and Urostylidae are placed in synonymy, assigned to other families, or held in uncertain familial relationship pending their rediscovery and further investigation.

Notes: SYNOPSISUltrastructure of the plasmodium wall and of sporogenesis were studied in Myxosoma funduli Kudo infecting the gills of Fundulus kansae (Garman). Plasmodia were located within the lamellar tissues adjacent to sinuses and capillaries. The plasmodium wall consisted of a single unit membrane which was continuous with numerous pinocytic canals extending into the parasite ectoplasm. The plasmodium membrane was covered by a surface coat of almost uniform thickness which prevented direct parasite-host cell contact. Numerous generative cells and cell aggregates, representing early stages of spore development, were seen in immature plasmodia. Later stages of spore development, including mature spores, were observed in older plasmodia. Sporogenesis was initiated by envelopment of one generative cell, the sporont, by a 2nd, nondividing cell, the envelope cell. The sporont and its progeny proceeded through a series of divisions until there were 10 cells, all compartmentalized within the envelope cell. Subsequently, the 10 cells became structurally differentiated and arranged into two 5-celled spore-producing units, each consisting of 1 binucleate sporoplasm and 2 capsulogenic cells, all surrounded by 2 valvogenic cells. Observations of later developmental stages revealed the major events of capsulogenesis, valvogenesis, and sporoplasm maturation, which occurred concomitantly during spore construction.

Notes: Richmond, M. H. & Smith, D. C., eds. 1979. The Cell as a Habitat.

Notes: SYNOPSIS Exoerythrocytic merozoites of Plasmodium lophurae grown in embryonic turkey brain cells were successfully separated from host cell material by elution from a DEAE-cellulose column at ionic strength 0.22. Purity of parasite samples was assessed by sodium dodecyl sulphate acrylamide gel electrophoresis and electron microscopy. Increasing the ionic strength gave greater recoveries of merozoites, but host cell contamination increased.

Notes: SYNOPSIS Blastocrithidia culicis, Crithidia deanei, Crithidia fasciculata, Herpetomonas samuelpessoai, Leptomonas seymouri and Leishmania tarentolae grown in cultures were compared by electrophoretic mobility for isoenzymes in 6 enzymes. All species were found distinct in these characteristics. Endosymbiotic C. deanei, which was identical to the aposymbiotic C. deanei in 5 enzymes, had an extra band in aspartate aminotransferase. No differences in isoenzymes were found between members of one species maintained in 2 different culture media.

Notes: RESUME.Des divisions synchrones chez Euglena gracilis Z peuvent ětre obtenues par différentes méthodes. Lorsque les cellules sont cultivées sur milieu contenant du lactate comme seule source de carbone, des divisions synchrones sont observables, indépen-damment des conditions d'éclairement. Toutefois, il existe une relation entre la phase des divisions cellulaires et les périodes lumière-obscurité appliquée à la culture.Pendant le cycle cellulaire, nous montrons que les synthèses des macromolécules sont discontinues: c'est le cas pour les ADN nucléaire et mitochondrial, les ARN ribosomaux et non-ribosomaux, ainsi que pour certaines protéines (cytochrome c 558). Des variations cycliques touchant la morphologie des mitochondries et des chloroplastes sont observées. Au cours du cycle cellulaire, les processus métaboliques séquentiels accompagnent les modifications de structure des organites. C'est ainsi qu'en début du cycle, au commencement de la phase G1, sont synthétisés les ribosomes cytoplasmiques et qu'ensuite, chez les euglènes vertes, les ARN non-ribosomaux sont formés.Ces synthèses d'ARN précèdent l'accroissement du chondriome et du plastidome dans la cellule. En milieu de phase G1, une nouvelle synthèse d'ARN non-ribosomal commence et est observée avant la synthèse des ADN nucléaire et mitochondrial. En fin de phase G1, démarre la division des organites à partir du chondriome et du plastidome en réseau.SYNOPSIS.Synchronous divisions of Euglena gracilis strain Z can be obtained by various methods. When the cells are cultivated in a medium containing lactate as the sole carbon source, synchronous divisions are observed, independent of the conditions of illumination. Nevertheless, there exists a relationship between the phase of cell division and the periods of light and darkness applied to the culture.During the cell cycle, the synthesis of macromolecules is discontinuous—this is true of nuclear and mitochondrial DNA, ribosomal and nonribosomal RNA, and certain proteins (cytochrome c 558). Cyclic variations in the structure of mitochondria and chloroplasts are also observed. In the course of the cell cycle, sequential metabolic processes accompany structural modifications of the organelles. Also, at the beginning of the cycle, at the start of phase G1, the cytoplasmic ribosomes are synthesized, and then, in green euglenids, nonribosomal RNAs are formed. These syntheses of RNA precede enlargement of the chondriome and plastids. In mid-G1 phase, a new synthesis of RNA begins, which precedes synthesis of nuclear and mitochondrial DNA. At the end of G1 phase, division of organelles starts, beginning with the chondriome and plastids, arranged in a network.

Notes: SYNOPSIS Cell-free synthesis of high molecular weight polypeptides, programmed by RNA from Tetrahymena pyriformis strain W is reported, and methods for preparation of the RNA are described. The RNA was extracted by the SDS-phenol-chloroform-isoamyl alcohol technic. The bulk of extracted RNA was ribosomal and on sucrose gradients peaked at -17S and 25S. After heat denaturation all the 25S RNA was converted to 17S. indicating the presence of hidden breaks, possibly the result of nuclease activity during extraction. Nevertheless, when poly(A)–RNA was collected using oligo-(dT)-cellulose column chromatography, it promoted a 15–fold increase in incorporation of [35S] methionine into TCA-precipitable material. Slab-gel electrophoresis and autoradiography of the product revealed 12 different major polypeptides, varying in weight from 28.000 to 65,000 Daltons. A method for preparation of translatable RNA from Tetrahymena will make possible the comparison of messenger RNAs associated with specific cell structures and with different developmental events.

Notes: SYNOPSIS. Lorica building was studied experimentally for Tintinnopsis parva Merkle, an agglutinated tintinnid. This species incorporated either siliceous or Ca-rich particles. Evidence of agglutination was seen within 30 min after the addition of particles to cultures of the protozoa. Fully agglutinated loricae were produced by the proter; partially incrusted loricae attributed to an opisthe were also recovered. The cytoplasmic evaginations of unknown function called striae were seen in the scanning electron microscope in better relief than ever before. They may provide the mechanism whereby the enclosed capsules are brought into contact with prey organisms.

Notes: SYNOPSIS. Culture procyclic forms of Trypanosoma brucei rhodesiense and Trypanosoma congolense were fed to Glossina morsitans morsitans through artificial membranes. A very high percentage of the flies so fed produced established midgut infections, a proportion of which went on to develop into mature metacyclic trypanosomes capable of infecting mammalian hosts. The method offers a safe, clean way of infecting tsetse flies with African trypanosomes which reduces the need for trypanosome-infected animals in the laboratory.