Gametting

Fig. 3. Forms of composite gemstones (a) doublet (b) fused gamet-top doublet (c) and (d) triplets (e) opal doublet (f) opal triplet (g) and (h) gel-filled...

Female sexual development and behaviour in mammals occurs by default and requires no ovarian secretion, and it is only in genetic males that the testis can secrete hormones which destroy this female pattern and superimpose that of the male. Sexual differentiation is not so well defined in fish, and larval exposure to both synthetic estrogens and androgens is widely used in aquaculture to produce monosex cultures. Endocrine disruption of sexual differentiation in fish may therefore reflect both the complexity and diversity of such processes between different species. Some care is required in use of the terms hermaphrodite and sex-reversal since a true hermaphrodite has both functional testes and ovaries and a sex-reversed fish is fully functional as its final sex—both produce the appropriate viable gametes. Such functional sex-reversal is not possible in mammals, but in some species of fish it is the normal developmental pattern. In most of the cases of hermaphroditism or sex-reversal reported in the non-scientific press, there is evidence only for a few ovarian follicles within a functional testis. This may be considered as feminisation or a form of intersex, and is very clearly endocrine disruption, but it is certainly neither sex-reversal nor hermaphroditism. In some cases the terms have even been used to infer induction of a single female characteristic such as production of yolk-protein by males. 

Sirenin is the sperm attractant produced by the female gametes of the water mold, Allomyces. Its synthesis has been accomplished by the use of an internal [2 + 1] cycloaddition step. 

Jobling, S., Beresford, N., and Nolan, M. (2002b). Altered sexual maturation and gamete production in wild roach (Rutilus rutilus) living in rivers that receive treated sewage effluents. Biology of Reproduction 66, 272-281. 

Human Spontaneous Abortions with Chromosomal Abnormalities", Aging Gametes, Int. Symp. Seattle, (1975), 330-348. 

AGULLO G, GAMET-PAYRASTRE L, MANENTI S, VIALA C, REMESY C, CHAP H and PAYRASTRE B... 

GAMET-PAYRASTRE L, LI P, LUMEAU S, CASSAR G, DUPONT M A, CHEVOLLEAU S, GASC N,... 

GAMET L, DAViAUD D, DENis-POUXViEL 0, REMESY 0, MURAT J 0 (1992) Effects of shoit-chain fatty acids on growth and differentiation of the human colon-cancer cell line HT29. Int J Cancer. 52 286-9. 

Stracke A, Salters VJM, Sims KWW (1999) Assessing the presence of gamet-pyroxenite in the mantle sources of basalts through combined hafnium-neodymium-thorium isotope systematics. Geochem Geophys Geosyst L1999GC000013... 

D s were calculated assuming 60% cpx, 40% garnet and no rutile using values from Keppler (1996) and gamet/melt cpx/melt partition coefficients to estimate gamet/fluid partitioning. ... 

The vertebrates produce, send and detect information which is conveyed by one or more molecular types. Chemical information of biological value (semiochemicals) which partly or wholly activates the accessory olfactory system (AOS) is transferred during intra- and inter-species communication. The compounds involved convey messages of social importance originating from the need to co-ordinate gamete release. It seems quite likely that gradual improvements by selection of semiochemical molecules and their receptors eventually enhanced the reproductive benefits both for the sender and for the receiver (Sorensen, 1996). The dual olfactory systems interpret chemical input to allow the discrimination of odour... 

Leyton, L., LeGuen, P Bunch, D., and Saling, P. M. (1992). Regulation of mouse gamete interaction by a sperm tyrosine kinase. Proc. Nad. Acad. Sci. USA 59 11692-11695. 

Borsuk E, Manka R 1988 Behavior of sperm nuclei in intact and bisected metaphase II mouse oocytes fertilized in the presence of colcemid. Gamete Res 20 365-376 Ciemerych MA 1995 Chromatin condensation activity and cortical activity during the first three cell cycles of mouse embryo. Mol Reprod Dev 41 416—424 Ciemerych MA, Kubiak JZ 1999 Transient reactivation of CSF in parthenogenetic one-cell mouse embryos. Biol Cell 91 641—647... 

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