Genetics of Gracilaria tikvahiae (Rhodophyceae). VII. Further observations on mitotic recombination and the construction of polyploids

1981 ◽  
Vol 59 (5) ◽  
pp. 787-792 ◽  
Author(s):  
John P. van der Meer
Keyword(s):  
Somatic Cells ◽  
Reproductive Behaviour ◽  
Mitotic Recombination ◽  
Red Alga ◽  
Crossing Experiments ◽  
Free Living ◽  
Male And Female ◽  
Gracilaria Tikvahiae ◽  
Morphological Mutants ◽  
Male Tissue

Tetrasporophytes of the marine red alga Gracilaria tikvahiae produce spermatia as well as tetraspores. It has been demonstrated previously that these spermatia are diploid and are produced as a consequence of mitotic recombination in somatic cells of the fertile thallus. It has now been demonstrated that female tissue is also present, often adjacent to the male tissue as would be expected, but is more difficult to recognize because it rarely becomes fertile. However, it was found that female tissue could be excised from the tetrasporophyte and induced to regenerate into complete fronds. Crossing experiments indicated that this female tissue was functional and diploid like the corresponding male tissue. Diploid male and female fronds have been established in culture as free-living plants. Morphological mutants of Gracilaria were found useful in obtaining stocks of diploid gametophytes. Triploid and tetraploid sporophytes were readily synthesized by using the diploid gametophytes (or spermatia from normal diploid tetrasporophytes) in crosses to each other or to normal haploid gametophytes. In one case an apparent tetraploid was synthesized by crossing a haploid female with a triploid tetrasporophyte. In this work polyploid designations are made on the basis of the method of construction and the reproductive behaviour of the polyploids. Cytological confirmation (made for a triploid previously) is incomplete for tetraploids but supports the designations that have been made.

The Reproductive Behaviour of Gynandromorphic Drosophila melanogaster

1978 ◽  
Vol 33 (9-10) ◽  
pp. 744-754 ◽  
Author(s):  
Robert Cook
Keyword(s):  
Quantitative Analysis ◽  
Reproductive Behaviour ◽  
Neural Circuitry ◽  
Chromosome Loss ◽  
Male Courtship ◽  
Male And Female ◽  
Perfect Subset ◽  
Female Behaviour ◽  
The Brain ◽  
Male Tissue

Abstract Reproductive behaviour was studied in 192 gynandromorphs with female genitalia and reproductive system, produced by ring-X chromosome loss. Male and female behaviour patterns were frequently found to coexist in the same individuals, and male courtship behaviour, when it occurred, retained its characteristic hierarchical organisation. Sexually receptive individuals were found to be an almost perfect subset of those ovipositing, and the control of both of these behaviours mapped to the head, as did male orientation (courtship). High rates of wing flicking, a response of males to courtship, mapped rather to the thorax, although a quantitative analysis demonstrated that the frequency of flicking behaviour was also influenced by male tissue in the head. In non-ovipositing individuals mature oocytes were retained in the ovary. An egg held in the uterus is not deposited by a fly without female tissue in the head and all but one sexually receptive individuals laid eggs. It is therefore concluded that both of these behaviours depend upon closely related neural circuitry operating the genital musculature under control from the brain.

scholarly journals Evolutionary insight from a humble fly: sperm competition and the yellow dungfly

2020 ◽  
Vol 375 (1813) ◽  
pp. 20200062
Author(s):  
Leigh W. Simmons ◽  
Geoff A. Parker ◽  
David J. Hosken
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Paradigm Shift ◽  
Mate Guarding ◽  
Reproductive Behaviour ◽  
Costs And Benefits ◽  
Theme Issue ◽  
Male And Female ◽  
Sexual Selection Theory ◽  
The 1960S

Studies of the yellow dungfly in the 1960s provided one of the first quantitative demonstrations of the costs and benefits associated with male and female reproductive behaviour. These studies advanced appreciation of sexual selection as a significant evolutionary mechanism and contributed to the 1970s paradigm shift toward individual selectionist thinking. Three behaviours in particular led to the realization that sexual selection can continue during and after mating: (i) female receptivity to remating, (ii) sperm displacement and (iii) post-copulatory mate guarding. These behaviours either generate, or are adaptations to sperm competition, cryptic female choice and sexual conflict. Here we review this body of work, and its contribution to the development of post-copulatory sexual selection theory. This article is part of the theme issue ‘Fifty years of sperm competition’.

Changes in serum concentrations of steroids during embryonic and post-hatching development of male and female Japanese quail (Coturnix coturnix japonica)

1988 ◽  
Vol 118 (1) ◽  
pp. 127-134 ◽  
Author(s):  
M. Schumacher ◽  
J. Sulon ◽  
J. Balthazart
Keyword(s):  
Japanese Quail ◽  
Reproductive Behaviour ◽  
Coturnix Japonica ◽  
Coturnix Coturnix Japonica ◽  
Serum Concentrations ◽  
Male And Female ◽  
Coturnix Coturnix ◽  
Hatching Time ◽  
Embryonic Life ◽  
Age Range

ABSTRACT Serum concentrations of testosterone, 5α-dihydrotestosterone, oestradiol and progesterone were measured by radioimmunoassay combined with Celite chromatography in male and female Japanese quail (Coturnix coturnix japonica) during the second half of embryonic life (days 9–17 of incubation) and during the first 5 weeks after hatching. The mean level of each of the four steroids was significantly affected by the age of the birds. An overall effect of sex was detected by analysis of variance only on oestradiol concentrations, with females having higher serum concentrations than males during most of the age range studied. Significant peaks of testosterone and progesterone were also detected around hatching time. These results are consistent with the view that oestradiol is the major hormone implicated in the sexual differentiation of reproductive behaviour in the quail. The relationships between the circulating concentrations of oestradiol during ontogeny and the critical period of differentiation as postulated by currently accepted models is also discussed. J. Endocr. (1988) 118, 127–134

scholarly journals Abnormal Meiosis Initiation in Germ Cell Caused by Aberrant Differentiation of Gonad Somatic Cell

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Min Chen ◽  
Min Chen ◽  
Suren Chen ◽  
Jingjing Zhou ◽  
Fangfang Dong ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Germ Cell ◽  
Somatic Cell ◽  
Germ Cells ◽  
Somatic Cells ◽  
Ectopic Expression ◽  
Genital Ridge ◽  
Male And Female ◽  
Germ Cell Differentiation ◽  
Exact Function

The interaction between germ cell and somatic cell plays important roles in germ cell development. However, the exact function of gonad somatic cell in germ cell differentiation is unclear. In the present study, the function of gonad somatic cell in germ cell meiosis was examined by using mouse models with aberrant somatic cell differentiation. In Wt1R394W/R394W mice, the genital ridge is absent due to the apoptosis of coelomic epithelial cells. Interestingly, in both male and female Wt1R394W/R394W germ cells, STRA8 was detected at E12.5 and the scattered SYCP3 foci were observed at E13.5 which was consistent with control females. In Wt1-/flox; Cre-ERTM mice, Wt1 was inactivated by the injection of tamoxifen at E9.5 and the differentiation of Sertoli and granulosa cells was completely blocked. We found that most germ cells were located outside of genital ridge after Wt1 inactivation. STRA8, SYCP3, and γH2AX proteins were detected in germ cells of both male and female Wt1-/flox; Cre-ERTM gonads, whereas no thread-like SYCP3 signal was observed. Our study demonstrates that aberrant development of gonad somatic cells leads to ectopic expression of meiosis-associated genes in germ cells, but meiosis was arrested before prophase I. These results suggest that the proper differentiation of gonad somatic cells is essential for germ cell meiosis.

scholarly journals Life cycle of Craspedacusta sowerbyi xinyangensis

2009 ◽  
Vol 55 (3) ◽  
pp. 227-234 ◽  
Author(s):  
Shanliang Xu ◽  
Danli Wang
Keyword(s):  
Life Cycle ◽  
Light Microscopy ◽  
Digital Camera ◽  
Zhejiang Province ◽  
The Other ◽  
Free Living ◽  
Cell Stage ◽  
Germ Layers ◽  
Male And Female ◽  
Gastrovascular Cavity

Abstract To explore the life cycle of Craspedacusta, the authors collected male and female specimens of the Craspedacusta sowerbyi xinyangensis in a small fire-fighting pond in Ningbo, Zhejiang Province in July, 2005 and 2006. The development of C. sowerbyi xinyangensis was studied from zygote to medusa by means of light microscopy and digital camera. The zygotes of C. sowerbyi xinyangensis are globular and smooth (90 - 105 μm diameter) and have an equal, total cleavage to the two-cell stage 15 min after fertilization. The embryos enter the four-cell stage after another 15 min and become multicellular embryos after 3h 15 min. At this stage the embryos have a diameter similar to fertilized eggs but have uneven surfaces that are distinct from the smooth surfaces of the uncleaved zygotes. Solid gastrulae are formed 7 h after fertilization. These are spherical planulae with short surface cilia that begin to swim in slow clockwise circles. After 12 h, they lose their cilia, cease swimming and become elongated planulae with one end larger than the other. Rod-like planulae, similar in thickness at both ends, are formed after an additional 7 h. After 4 days, the planulae develop into tiny polyps having two germ layers and a gastrovascular cavity. The polyp mouth is 50 - 62 µm in diameter, lacking tentacles but having nematocysts around the mouth. Planulae become mature polyps after 10 days (15 days after fertilization). Medusa buds (45 - 88 μm diameter) are formed by polyp budding, which soon become free-living medusae with 8 tentacles (380 - 620 μm diameters). Sometimes, the movement of frustules, which are formed by the polyps and similar to planulae in morphology can also be observed.

VARIATION IN PACIFIC SALMON REPRODUCTIVE BEHAVIOUR ASSOCIATED WITH SPECIES, SEX AND LEVELS OF COMPETITION

Behaviour ◽  
1999 ◽  
Vol 136 (2) ◽  
pp. 179-204 ◽  
Author(s):  
Thomas Quinn
Keyword(s):  
Pacific Salmon ◽  
Local Area ◽  
Reproductive Behaviour ◽  
Male Aggression ◽  
Male And Female ◽  
Sexual Display ◽  
Resource Space ◽  
Intensity Of Competition ◽  
Satellite Males ◽  
Spawning Sites

AbstractMale and female Pacific salmon compete for different resources; females for suitable spawning sites and males for access to ripe females. Aggression should thus be primarily intra-sexual rather than inter-sexual. When different species are sympatric, males should primarily attack conspecifics whereas females should attack all females, regardless of species because they all compete for the same resource-space. The level of aggression should be a function of density, being relatively low at low densities and peaking at either intermediate or high densities. These predictions were supported in most respects by data collected on the behaviour of adult sockeye (Oncorhynchus nerka), chum (O. keta) and pink (O. gorbuscha) salmon in a large, relatively homogeneous spawning channel. Males almost exclusively attacked other males, especially conspecifics. Females were more likely to attack female heterospecifics than males but still tended to attack conspecifics most often, and also directed many attacks at males. Male aggression and digging, apparently a form of intra-sexual display, were related to density of male conspecifics in the local area, and the intensity of competition from satellite males courting the female.

Marine Flatworms

2003 ◽  
Author(s):  
Leslie Newman ◽  
Lester Cannon
Keyword(s):  
Feeding Habits ◽  
Reproductive Behaviour ◽  
Zoological Museum ◽  
Free Living ◽  
Unusual Structure ◽  
Sea Slugs ◽  
The World ◽  
Polyclad Flatworms ◽  
Colour Patterns ◽  
Brilliant Colour

Marine Flatworms provides a fascinating introduction to the intriguing world of polyclad flatworms, a group of large, free-living marine Platyhelminthes, which are found throughout the world but are most colourful in tropical waters. Although not related to molluscs, they are often mistaken for sea slugs because of their brilliant colour patterns. Written in an accessible style by two leading experts in the field, this book explores flatworms’ unusual structure, feeding habits, their curious reproductive behaviour (including ‘penis fencing’), their mimicry and toxicology. With a foreword by Professor Reinhardt Kristensen of the Copenhagen Zoological Museum, Marine Flatworms is the first comprehensive guide to polyclad families and genera. It contains more than 300 colour photographs from every part of the world.

Physiological maturation and reproductive behaviour of female doves (Streptopelia risoria) held under long and short photoperiods

1976 ◽  
Vol 54 (3) ◽  
pp. 343-354 ◽  
Author(s):  
N. R. Liley
Keyword(s):  
Nest Site ◽  
Reproductive Behaviour ◽  
Egg Laying ◽  
Nest Building ◽  
Short Photoperiod ◽  
Courtship Behaviour ◽  
Male And Female ◽  
Streptopelia Risoria ◽  
Long Photoperiod

Female doves were held under long (16 h per day), or short (8 h per day) photoperiod and exposed to actively courting males for 4.5 h per day for 15 days. The occurrence of egg laying and nest building was recorded daily. Behavioural observations were recorded for 15 min on alternate days.Seven out of eight long-photoperiod females laid eggs, whereas only one of nine short-photoperiod females began egg laying. Soliciting by the female and nest building involving male and female are the best indicators of a female's readiness to begin breeding. The occurrence of these activities is correlated with the growth of follicles and oviduct. Copulation and associated behaviours are not correlated with follicle and oviduct growth, and appear to be controlled by factors different from those governing courtship behaviour associated with the nest site.

Effects of temperature and tissue age on gel strength and composition of agar from Gracilaria tikvahiae (Rhodophyceae)

1984 ◽  
Vol 62 (8) ◽  
pp. 1665-1670 ◽  
Author(s):  
James S. Craigie ◽  
Zong C. Wen
Keyword(s):  
Gel Strength ◽  
Wild Type ◽  
Gracilaria Tikvahiae ◽  
Morphological Mutants ◽  
Wild Type Clone ◽  
Effects Of Temperature ◽  
Lateral Branches ◽  
Increasing Temperature ◽  
Strong Inverse Relationship ◽  
Galactose Content

Agars were prepared from a wild type and two morphological mutants of Gracilaria tikvahiae grown at 17, 22, and 27 °C, and from apical segments, main axis segments, and lateral branches of the wild type clone MP-2 grown at 17 and 27 °C. The yield of native agar was 9–11% from the young parts and 19–23% from the most mature parts of the MP-2 thallus. The gel strengths of alkali-modified agars showed a strong inverse relationship with increasing temperature of growth in each of the three clones examined. The modified agar produced from plants grown at high temperature contained more sulfate and less 3,6-anhydro-L-galactose than agars produced at lower temperatures. The increase in 4-O-methyl-L-galactose content of the agars as the growth temperature increased was especially marked. Dissection experiments on clone MP-2 showed that agar with the maximum gel strength and 3,6-anhydro-L-galactose content and the minimum sulfate and 4-O-methyl-L-galactose content was produced at low temperature by apical segments and young lateral branches. The poorest quality agar was prepared from mature segments of the thallus, especially those grown at high temperatures. Agars prepared from mature parts of the thallus were greatly enriched in 4-O-methyl-L-galactose, which reached 8.8% of the weight of the agar at 27 °C. Changes in 6-O-methyl-D-galactose were smaller, but this sugar was lowest in agar prepared from young tissues of plants grown at 17 °C.

Carrageenans of gametangial and tetrasporangial stages of Iridaea cordata (Gigartinaceae)

1975 ◽  
Vol 53 (20) ◽  
pp. 2315-2318 ◽  
Author(s):  
E. L. McCandless ◽  
J. S. Craigie ◽  
J. E. Hansen
Keyword(s):  
Infrared Spectra ◽  
Red Alga ◽  
Sulfate Content ◽  
Male And Female ◽  
Iridaea Cordata

Carrageenans from gametangial (male and female) and tetrasporangial plants of the red alga Iridaea cordata were isolated, fractionated, and characterized on the basis of their anhydrogalactose and sulfate content and infrared spectra. As in the case of Chondrus crispas the tetrasporangial plants yielded only λ-carrageenan while the gametangial plants produced carrageenans of the κ-type. The male plants yielded proportionately more KCl-insoluble κ-carrageenan than did the female. The infrared spectra of the various preparations from I. cordata were virtually indistinguishable from those of comparable fractions isolated from C. crispus.

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