Life Cycle of Polytomella caeca (Phytomonadida, Polyblepharidae)

SYNOPSIS. Polytomella caeca (Phytomonadida, Polyblepharidae) reproduce by binary fission and sexual reproduction. The sexual process increases in frequency as the population becomes denser. Normally 2 monoecious isogametes engage their anterior flagella prior to fusion, which occurs by merging of the cells from their anterior to their posterior ends. This is followed by a period of zygotic enlargement before cleavage of the zygote into 4 daughter cells. Encystment occurs throughout the flagellates' bloom until they represent 80% of the individuals at the end of the bloom. Cysts are a resistant, not reproductive stage. The observations were made over long periods of time by following individual flagellates in microcultures and by viewing living cells taken at various stages from larger cultures.     

Blood Protozoa of Wild Turkeys in Florida*

From 1969 through 1972, 605 wild turkeys (Meleagris gallopavo Linnaeus) from 10 localities in Florida were examined for blood protozoans. The prevalence in turkeys more than a month old was 84% for Haemoproteus meleagridis Levine, 1961 and 72% for Leucocytozoon smithi Laveran and Lucet, 1905. Sixty-three percent of the birds were infected by both parasites. Infections were most prevalent in juveniles 8–12 months of age. No infection of H. meleagridis or L. smithi was found in 111 poults younger than 35 days. Prevalences were similar in both sexes. Haemoproteus meleagridis was more prevalent (87%) in the southern part of the state; L. smithi was more prevalent (75%) in the north. The prevalence of H. meleagridis did not change during the 4 year period, but L. smithi decreased markedly in 1971, a year of low rainfall. None of the 605 blood films was positive for Plasmodium, but 24 (75%) of 32 blood samples were found by subinoculation technics to be positive for a species of Plasmodium morphologically similar to P. durae Herman, 1941. No trypanosomes were seen on the 605 blood films or in bone marrow cultures (saline-neopeptone-blood) made from 11 turkeys.     

Three-Dimensional Structure of Macronuclei from Paramecium Determined by Scanning Electron Microscopy*

SYNOPSIS. Macronuclei of Paramecium primaurelia were isolated and examined by scanning electron microscopy. These nuclei consisted of a closely packed array of chromatin bodies measuring ～ 0.2 μm in diameter. We estimated there were ～ 30,000 such bodies/macronucleus, 20 times more than the number of unit genome equivalents. This suggests that a unit genome is physically shared by several chromatin bodies.     

Silica Gel as a Preserving Agent for the Cellular Slime Mold Acrasis rosea

SYNOPSIS. Modifications of the silica gel technic of Perkins and Ogata have been successfully used to preserve Acrasis rosea for 6–13 months and Dictyostelium purpureum for 31 months. The technic is simple, reliable and inexpensive and is recommended for its possible application for the general preservation of certain fungi and protozoa.     

A revision of the Adeshini van Achterberg with descriptions of three new genera from the Palaeotropics (Insecta, Hymenoptera, Braconidae)

Furcadesha gen. n. (type-species: Furcadesha huddlestoni sp.n), Indadesha gen. n. (type-species: Indadesha achterbergi sp.n), both from India, and Africadesha gen.n. (type-species: Africadesha usherwoodi sp.n). from Cameroun, are described and illustrated. A key is provided to separate these new genera from one another and from the other genera of the Adeshini, Adesha Cameron and Adeshoides van Achterberg. Adesha acuta sp.n. from Malaya is described and separated from Adesha albolineata Cameron, the only other species of Adesha. The relationships of the Adeshini and of the genera of the Adeshini are briefly discussed.     

Carbohydrate Analysis of Floral and Extra-floral Nectars in Selected Taxa of Sansevieria (Agavaceae)

A comparative analysis of the simple carbohydrates (fructose,glucose, sucrose) between floral and extra-floral nectars wasperformed among 17 taxa and two established cultivars of Sansevieria.Floral nectars (FNs) were found to be universally sucrose dominant,while extra-floral nectars (EFNs) were extremely sucrose poor(hexose dominant). Monosaccharide: saccharide ratios for FNsvaried from 1: 1.1 to 1: 4.4. By contrast, monosaccharide: disaccharideratios of EFNs varied from 6.0: 1 to 17.1: 1. Floral and inflorescencemorphology in addition to chemical factors strongly suggesta hawkmoth pollinated syndrome. Extra-floral nectaries may provideprotection of the inflorescence against herbivores by ants orother aggressive insects. Sansevieria, Agavaceae, floral nectars, extra-floral nectars, pollination     

Thickness Fluctuations in Veins of Corn and Sunflower detected by a Linear Transducer

A short-stroke linear displacement transducer has been usedto detect changes in thickness of veins of corn and sunflower.After illumination, continual fluctuations in thickness occurred,some 2–5 min and others 15–20 min apart and from0.05% to 2% of the total vein thickness in amplitude. Thesechanges, often erratic and usually not simultaneous at points4.0 cm apart, seem to be related to changes in water potentialin the tissue. The short-term fluctuations were not due to majorstomatal oscillations but could be due to local variations intranspiration, or to fluctuations in photosynthate moving throughthe veins, for they often resembled the patterns of radioactivitydetected after feeding ¹¹CO₂or ¹¹C-sucrose. The magnitude offluctuation increased as the diameter of vein increased, andthus could be useful in monitoring changes of water potentialin leaves.