Mating‐Type Dependent Cell Pairing in <i>Oxytricha hymenostoma. III. Chromatin Mixing After Macronuclear Fusion</i>*

Banchetti, Rosalba; Nobili, Renzo; Ricci, Nicola; Esposito, Fulvio

doi:10.1111/j.1550-7408.1980.tb05398.x

Cited by 5 publications

(5 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The behaviour of the maternal macronuclei during conjugation has been described for other hypotrichs : Stylonychia (Alonso & Pkrez-Silva, 1965 ;Moldenhauer, 1965 ;Sapra & Dass, 197ob, 1973 ;Shi, 1975;Yano, 1985 a), Paraurostyla (Jerka-Dziadosz, 1975), Pseudourostyla (Takahashi, 1974;Jin & Ng, 1990), Oxytricha (Gregory, 1923 ;Kay, 1946;Diller, 1965;Ricci et al, 1975;Ricci & Banchetti, 1981), Pleurotricha (Manwell, 1928), Uroleptus (Calkins, 1919(Calkins, , 1930. Two or more macronuclei are usually present in these hypotrichs.…”

Section: ) Why Is the Second Reorganization Incomplete In Other Hypomentioning

confidence: 85%

“…Apart from these two genera, preliminary mitosis does not occur during conjugation in other hypotrichs examined. These include Stylonychia, Oxytricha, Kahliella, Aspidisca, Paraurosytla, Diophrys, Pleurotricha, Onychodromus, Uroleptus and Uronychia (for citations see Raikov, 1972, Table I ; additional references: Calkins, 1919Calkins, , 1930Ito, 1963;JareAo, Alonso & Perez-Silva, 1969Diller, 1975;Jerka-Dziadosz & Janus, 1975;Shi, 1975;Ricci & Banchetti, 1981;Yano, 19856;Dini, Bracchi & Gianni, 1987; the references to the first micronuclear division during conjugation as preliminary mitosis in Stylonychia mytilus (Nakata,I 954), and in Diophrys scutum (Ito, 1954), may be regarded as misnomers).…”

Section: Development and Evolution In Ciliatesmentioning

confidence: 99%

“…The chromatin may develop vacuoles, or become condensed at the center of the nucleus. Such deterioration takes place during micronuclear meiosis (in Uroleptus -Calkins, 1930; in Pseudourostyla -Takahashi, 1974;Jin & Ng, 1990; in Stylonychia mytilus, at 6 h in a 24 h conjugation period -Sapra & Ammermann, 1973), or around the time of formation of the zygotic nucleus and the first postzygotic division (in Oxytricha -Kay, 1946;Ricci & Banchetti, 1981), or during the second postzygotic division (in Pleurotricha -Manwell, 1928; in Stylonychia mytilus -Shi, 1975). This differs from the situation in Euplotes where the posterior macronuclear fragment(s) maintain their structural integrity throughout sexual development and even in some cases up to the first post-conjugal cell fission.…”

Section: Iv(1 C ) ]mentioning

confidence: 99%

“…These include Stylonychia, Oxytricha, Kahliella, Aspidisca, Paraurosytla, Diophrys, Pleurotricha, Onychodromus, Uroleptus and Uronychia (for citations see Raikov, 1972, Table I ; additional references: Calkins, 1919Calkins, , 1930Ito, 1963;JareAo, Alonso & Perez-Silva, 1969Diller, 1975;Jerka-Dziadosz & Janus, 1975;Shi, 1975;Ricci & Banchetti, 1981;Yano, 19856;Dini, Bracchi & Gianni, 1987; the references to the first micronuclear division during conjugation as preliminary mitosis in Stylonychia mytilus (Nakata,I 954), and in Diophrys scutum (Ito, 1954), may be regarded as misnomers). These include Stylonychia, Oxytricha, Kahliella, Aspidisca, Paraurosytla, Diophrys, Pleurotricha, Onychodromus, Uroleptus and Uronychia (for citations see Raikov, 1972, Table I ; additional references: Calkins, 1919Calkins, , 1930Ito, 1963;JareAo, Alonso & Perez-Silva, 1969Diller, 1975;Jerka-Dziadosz & Janus, 1975;Shi, 1975;Ricci & Banchetti, 1981;Yano, 19856;Dini, Bracchi & Gianni, 1987; the references to the first micronuclear division during conjugation as preliminary mitosis in Stylonychia mytilus (Nakata,I 954), and in Diophrys scutum (Ito, 1954), may be regarded as misnomers).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

1990

Biological Reviews

View full text Add to dashboard Cite

Section: ) Why Is the Second Reorganization Incomplete In Other Hypomentioning

confidence: 85%

Section: Development and Evolution In Ciliatesmentioning

confidence: 99%

Section: Iv(1 C ) ]mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

1990

Biological Reviews

View full text Add to dashboard Cite

“…Anomalous cases of conjugation, reported in a number of hypotrichs, fall into two categories. The first category includes mates that permanently fused with each other, sometimes referred to as total conjugation (Stylonychia pustulata [36], Sty-1onychi.a putrina [9], Stylonychia mytilus [3 11, Pseudourostyla levis , Onychondromus [ 121, Oxytricha hymenostoma [5,6,101. Such conjugants do not exhibit a normal sexual cycle, but instead nuclear behavior indicates they undergo asexual development.…”

mentioning

confidence: 99%

Anomalous Cases of Conjugation and Spontaneous Autogamy in Stylonychia mytilus: A Note on the Asexuality of Early Conjugants

Zou

1991

The Journal of Protozoology

View full text Add to dashboard Cite

Four types of anomalous conjugation were documented in Stylonychia mytilus. Type I pairs were formed between mates of different sizes. These pairs exhibited an abnormal site of fusion in at least one of the mates, and the mates might face each other ventrally throughout conjugation instead of the normal side‐by‐side position. Type I pairs underwent sexual nuclear development and proceeded with the first cortical reorganization as in normal conjugants. Type II involved pairing at the anterior ends of mates with ventral surfaces facing the same direction. These pairs also underwent sexual nuclear development. Hence, aberrant orientation of the mates, and also ectopic sites of cytoplasmic fusion, if extensive, would permit sexual development. Type III pairs were united ventral‐to‐ventral with their anterior‐left sides at the adoral zone of membranelles, and remained as such throughout conjugation. In these pairs, nuclear and cortical events were typical of the asexual development of physiological reorganization. In Type IV pairs, one mate of the pair possessed a fission furrow and developed two sets of ciliature typical of binary fission, while the other mate might undergo physiological reorganization or binary fission. Type III and Type IV pairs thus reveal the asexual state of early conjugants, which can pursue either one of the two modes of asexual cortical reorganization; these cases reinforce the notion of overlap of asexual and sexual cycles during conjugation of hypotrichs. Spontaneous autogamy was documented for the first time for this genus. The autogamonts proceeded with nuclear development and with the first cortical reorganization. Some probably underwent second and third reorganizations, as in conjugants, but accompanied by abnormalities, particularly in the stages beyond fertilization. Post‐autogamous clones were nonviable except for one dubious case.

show abstract

Mating‐type dependent cell pairing in Oxytricha hymenostoma. IV. Macronuclear DNA content

Banchetti¹,

Cetera²,

Nobili³

et al. 1982

J. Exp. Zool.

Self Cite

View full text Add to dashboard Cite

The cytophotometric study of vegetative cells of Oxytrichu hymenostoma showed that the two complementary strains 295 and 301 differ from each other in their macronuclear DNA content: 902 arbitrary units (U) for 295 and 1365 U for 301.During paraconjugation, a phenomenon involving the total fusion of two complementary partners into a unique, new cellular entity, the macronuclear DNA contentlpair does not change strikingly: for the first 3 hr, in fact, the macronuclear DN.A content per pair ranges around 2250 U, such a value being very close to that of a 295 cell (902 U) plus that of a 301 cell (1365 U). Only at stages 6 and 7, an increase of the macronuclear DNA content occurs (+9%), which is likely to be due to ano:malous replication bands. Finally, at stages 8 and 9, the macronuclear DNA contentlpair progressively decreases, dropping to values as small as 2025 U, in spite of the apparently normal replication bands, passing through the macronuclear, soon before the first binary fission of the paraconjugant cell.Previous cytologic and ultrastructural analyses of the sexual reproduction of Oxytricha hymenostoma (Esposito et al., '78; Banchetti et al., '80a) showed that cells belonging to the complementary types 295 and 301 undergo a peculiar, total cell fusion, defined "paraconjugation" (Banchetti et al., '80b). The main traits of this process are (a) the lack of micronuclear meiosis and (b) the fusion of the macronuclear pieces of the two partners, with the formation of a unique cellular entity with an apparently normal cortical, cytoplasmic, and nuclear morphology. By genetic analysis (Banchetti et al., 'Sob) it was concluded that: (1) the observed mating-type assortment in the progeny indicates a macronuclear segregation and (2) the over-representation of 301 among the progeny cannot be ascribed to an imperfect mixing of macronuclear material, according to the electron microscopy examination (Banchetti et al., '80a).Does any preparaconjugative regulation of the DNA content take place? Does any postparaconjugative regulation of the DNA content take place? In an attempt to answer these questions, and on the basis of the results already acquired, a cytophotometric analysis of paraconjugation in 0. hymenostoma was conducted t o study the trend of the macronuclear DNA content during the various stages of the process. MATERIALS AND METHODSThe two strains RN3 and RBI, belonging to the complementary mating types of 295 and 301 of 0. hymenostoma, were used for this round of experiments. The cultures were grown according to the improved culturing techniques, already standardized for Oxytn'cha bifun'a (Ricci et al., '80a), and kept at a temperature of about 23 k 1°C. After a mild starvation, about 10-12 hr, cells of both mating types were mixed together and the pairs were isolated as soon as they formed. Every 30 min, from 0 to 9 hr, pairs of equal age were fixed by Sanfelice fixative (cromic acid 1% aqueous solution, 16 parts; Formalin, 8 parts; glacial acetic acid, 1 part), attached to the slides with 95% (vlv)...

show abstract

Mating‐Type Dependent Cell Pairing in *Oxytricha hymenostoma. III. Chromatin Mixing After Macronuclear Fusion**

Cited by 5 publications

References 7 publications

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

Anomalous Cases of Conjugation and Spontaneous Autogamy in Stylonychia mytilus: A Note on the Asexuality of Early Conjugants

Mating‐type dependent cell pairing in Oxytricha hymenostoma. IV. Macronuclear DNA content

Contact Info

Product

Resources

About

Mating‐Type Dependent Cell Pairing in Oxytricha hymenostoma. III. Chromatin Mixing After Macronuclear Fusion*

Cited by 5 publications

References 7 publications

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

Developmental Heterochrony in Ciliated Protozoa: Overlap of Asexual and Sexual Cycles During Conjugation

Anomalous Cases of Conjugation and Spontaneous Autogamy in Stylonychia mytilus: A Note on the Asexuality of Early Conjugants

Mating‐type dependent cell pairing in Oxytricha hymenostoma. IV. Macronuclear DNA content

Contact Info

Product

Resources

About

Mating‐Type Dependent Cell Pairing in *Oxytricha hymenostoma. III. Chromatin Mixing After Macronuclear Fusion**