Porphyrin Rings and Phospholipids: Stimulators of Cloning Efficiency in Certain Species of Tetrahymena

ABSTRACT. Species of Tetrahymena , including T. vorax, T. thermophila, T. pyriformis , and T. pigmentosa , were tested for cloning efficiency in proteose peptone and in synthetic nutrient media to which were added hemin, protoporphyrin IX, chlorophyllin, or asolectin, an impure mixture of phospholipids. All species could be cloned with high efficiency in the crude media. In unsupplemented synthetic medium the cloning efficiencies were 0–10%, around 50%, around 50%, and 90–100% for T. thermophila, T. vorax, T. pyriformis , and T. pigmentosa , respectively. The first three were all stimulated to 90–100% by addition of the porphyrin or phospholipid compounds mentioned above. Uroporphyrin III and coproporphyrin I and III had no effect. We suggest that cells unable to form clones suffer from a lack of cellular energy. This situation may be alleviated by our additions: certain porphyrin rings may be built into cytochromes and phospholipids may be used as fuel. Thus, the synthetic media used so far for these ciliates have not been optimal.     

Increased photoreversal of ultraviolet injury by flashing light

1. Photoreversal of ultraviolet (UV) injury was studied in the ciliate protozoan Tetrahymena pyriformis (geleii) strain W, cultured in the absence of other living organisms. The division pattern of progeny of single animals was followed in hanging drop preparations. 2. A sublethal dose of 450 ergs/mm.² of monochromatic UV of wave length 2654 A produces a lag before the first division followed by a period of cessation of fission after the second division. This cessation sometimes lasts as long as 6 weeks, during which time the animals become smaller and rounder and more opaque. Organisms about to resume division increase in size and transparency; after a few divisions the animals regain their normal division rate. 3. The effect of UV ranging in intensity from 5 to 15 ergs/mm.²/sec. was found to obey the reciprocity law quite well for the UV effect on the division pattern of T. pyriformis. However, the same dose at lower and at higher intensities was less effective. 4. The effect of a dose of UV delivered at high intensity (19 ergs/mm.²/sec.) could be increased by flashing the light, indicating that the system became saturated in the continuous light. 5. A photoreversing dose of monochromatic blue light of wave length 4350 A was found to be more effective when delivered as continuous light at a low intensity, or as intermittent light at a high intensity, rather than as continuous light at the high intensity—indicating that a dark mechanism participates in photoreversal. 6. The time for the dark reaction was determined to be of the order of a few hundredths of a second in experiments in which different lengths of dark period were used while maintaining a constant light period of 0.0025 second. 7. For Colpidium colpoda the efficiency of a given dose of photoreversing light was increased by flashing the light. 8. The present experiments are interpreted in terms of data available in the literature.     

Adverse effects of tempol on hidrosaline balance in rats with acute sodium overload

We studied the effects of tempol, an oxygen radical scavenger, on hydrosaline balance in rats with acute sodium overload. Male rats with free access to water were injected with isotonic (control group) or hypertonic saline solution (0.80 mol/l NaCl) either alone (Na group) or with tempol (Na-T group). Hydrosaline balance was determined during a 90 min experimental period. Protein expressions of aquaporin 1 (AQP1), aquaporin 2 (AQP2), angiotensin II (Ang II) and endothelial nitric oxide synthase (eNOS) were measured in renal tissue. Water intake, creatinine clearance, diuresis and natriuresis increased in the Na group. Under conditions of sodium overload, tempol increased plasma sodium and protein levels and increased diuresis, natriuresis and sodium excretion. Tempol also decreased water intake without affecting creatinine clearance. AQP1 and eNOS were increased and Ang II decreased in the renal cortex of the Na group, whereas AQP2 was increased in the renal medulla. Nonglycosylated AQP1 and eNOS were increased further in the renal cortex of the Na-T group, whereas AQP2 was decreased in the renal medulla and was localized mainly in the cell membrane. Moreover, p47-phox immunostaining was increased in the hypothalamus of Na group, and this increase was prevented by tempol. Our findings suggest that tempol causes hypernatremia after acute sodium overload by inhibiting the thirst mechanism and facilitating diuresis, despite increasing renal eNOS expression and natriuresis.     

Trypanosoma thecadactyli sp. n. from Forest Geckoes in Panama,and its Development in the Sandfly Lutzomyia trinidadensis (Newstead) (Diptera,Psychodidae)*

SYNOPSIS. Trypanosoma thecadactyli sp. n. is described from the forest gecko Thecadactylus rapicaudus in Panama. Blood smears from 18 of 25 (72%) geckoes sampled were positive for the new trypanosome. The flagellate, ～22 μm long, is ovoid or roughly triangular in shape and has a posterior cytoplasmic projection. Tree buttresses, rock crevices, and caves are microhabitats shared by T. rapicaudus and the phlebotomine sandfly Lutzomyia trinidadensis. Approximately 20% of the wild-caught and dissected L. trinidadensis were infected with flagellates. Twenty-four of 45 (53%) laboratory-reared L. trinidadensis allowed to feed on parasitized geckoes developed heavy infections of the mid- and hindgut which persisted up to 2 weeks, the longest postprandial period before dissection. Transmission probably occurs as a result of geckoes feeding on infected sandflies in nature. The distribution of L. trinidadensis, from Mexico to Brazil, approximates that of the gecko. Laboratory results and ecologic observations implicate L. trinidadensis as a potential vector of T. thecadactyli.     

Sporogenesis in Eusporangiate Ferns: I. Monoplastidic Meiosis in Angiopteris (Marattiales)

Angiopteris (Marattiales) undergoes the more primitive form of monoplastidic meiosis, while other ferns have evolved the polyplastidic type typical of seed plants. In monoplastidic cell division, the single plastid divides and serves as site of the microtubule organizing center (MTOC) for spindle formation resulting in coordinated division of plastid, nucleus, and cytoplasm. In plants with polyplastidic cell division, the MTOC is diffuse and generally perinuclear. Monoplastidic cell division is seen as a plesiomorphic feature that was inherited from algal ancestors containing a single plastid and modified through evolution. Monoplastidic meiosis occurs in all groups of bryophytes (although in only a few hepatics), Isoetes, Selaginella, certain generic segregates of Lycopodium, and in members of the Marattiales. It is not known to occur in psilophytes, Equisetum, leptosporangiate ferns, or seed plants. Received 30 January 2001/ Accepted in revised form 24 April 2001     

BULINUS AFRICANUS-GROUP SPECIES IN WEST AFRICA DIFFERENTIATED BY MORPHOMETRIC ANALYSIS (GASTROPODA, PLANORBIDAE)

In the present study 241 shells from snails belonging to theBulinus africanus-group in West Africa, were examined in a morphometricanalysis including ten characters. Principal component analysisand stepwise discriminant function analysis were used for analysisof the data. It was shown that Bulinus umbilicatus, B. jousseaumeiand B. globosus are clearly distinct on morphometric shell characters.Besides a general differentiation between the three species,the characters necessary for differentiation between them twoby two are found. The knowledge of the geographic distributionof B. umbilicatus and B. jousseaumei is significantly improved. (Received 18 March 1988; accepted 4 May 1988)