Auxin-induced heritable variants in yeast with special reference to physiological and genetic characters

A high concentration (400 mg/l) of an auxin, -naphthaleneaceticacid produced heritable variants differing in cell form andsize and in sporulation ability in a diploid strain of Saccharomycescerevisiae. These variants showed altered absorption spectrain the region of cytochromes a + a₃, b and/or c, but could growin a glycerol medium. Cultures of dissected spores from thesevariants involved many non-maters. These variants showed irregularsegregation of nutritional markers and/or a high DNA contentper cell. Since most of the variants grow more slowly on anauxin medium than does the original strain, they seem to beproduced by the induction by auxin rather than by selectiveenrichment. Genetic control of the ability to respond to auxinand the biological significance of auxin-induced variation inyeast is discussed. (Received January 12, 1968; )     

Breeding season, courtship behaviour, and territoriality of White and Japanese Wagtails Motacilla alba and M. grandis

The breeding ecology of White and Japanese Wagtails, Motacilla alba and M. grandis , was studied along a river in central Japan. The home ranges of the two species greatly overlapped along the river, but no interbreeding occurred. M. grandis spent more time on the river than M. alba and defended territories there. M. alba used the river as part of the entire home range, and did not defend the river areas as territories. Singing activity and breeding started earlier in M. grandis than in M. alba. The early breeding of M. grandis was related to the lack of moulting in spring, less necessity for pair formation due to the existence of pairs in the winter, and the greater dependency on larval than on adult insects. Songs were very different between the two species. The bowing display that preceded the pre-copulation display was found only in M. alba. During the pre-copulation display, male M. grandis lifted both wings above the horizontal while male M. alba drooped both wings. The pre-copulation display of M. grandis was similar to that of Large Pied Wagtails M. maderaspatensis in India, suggesting a closer relationship of the two species than to M. alba.     

Development of spermiduct and seminal vesicle during pharate adult of the cabbage armyworm,Mamestra brassicae, (Lepidoptera; Noctuidae)

Summary

Development of the upper vas deferens and seminal vesicle, and the ecdysteroid titers of the cabbage armyworm (Mamestra brassicae) during pharate adult stage were investigated to provide evidence of endogenous control of the sperm movement through the reproductive tract. Apparently, development of the upper vas deferens is initiated when ecdysteroid titers increase after pupation and continues until eclosion. Sperm movement correlates with the decrease of ecdysteroid titers. When ecdysteroid titers remained at low levels, sperm release from the testis was observed one day before eclosion.     

RESPONSIVENESS OF YEAST CELLS TO AUXIN, ANIMAL SEX HORMONES AND YEAST SEXUAL HORMONES IN RELATION TO SEX CONTROLLING GENES

Genetic control of the ability of yeast cells to respond to cell-expanding action of animal, plant and yeast hormones was studied. Mating type specificity in the ability to respond to yeast sexual hormones was changed by introduction of homothallism-controlling genes, D and HM. Auxin, a plant hormone can expand cells of most homothallic strains, but not those of heterothallic strains as far as tested. Animal sex hormones showed the action similar to that of yeast sexual hormones.     

The Wave Pattern of Free Calcium Release Upon Fertilization in Medaka and Sand Dollar Eggs

A transient rise in the concentration of Ca²⁺ in the cortex upon fertilization was demonstrated in medaka eggs injected with aequorin. Detection of the aequorin luminescence with an ultra-high sensitivity photonic microscope system revealed a wave of increased Ca²⁺ concentration starting at the site of sperm entry (animal pole) and being propagated along the cortex of the egg toward the antipode. The wave traversed the entire egg surface within 2–3 min. The peak value of the aequorin luminescence, and therefore the peak value of the Ca²⁺ transient, was generally higher at the site of sperm entry than in other regions. The peak values of the luminescence (and therefore of the Ca²⁺ concentration in the cortex) remained fairly constant during propagation of the wave. Microinjection of Ca²⁺ into the cortex also induced a Ca²⁺ wave. When the egg was stimulated by microinjection of Ca²⁺ at the equatorial region, the Ca²⁺ wave was propagated at a fairly constant speed over the egg surface, except at the region near the vegetal pole where the wave was retarded. Simultaneous recording of the Ca²⁺ wave and the wave of cortical change (breakdown of cortical alveoli) in eggs during fertilization revealed that the Ca²⁺ wave preceded the wave of cortical change.
A Ca²⁺ wave was also demonstrated in sand dollar eggs, although due to their smaller size the phenomenon was not as clear as in medaka eggs.     

The Participation of Speract in the Acrosome Reaction of Hemicentrotus pulcherrimus

A speract-free macromolecular fraction was prepared from the egg jelly of the sea urchin Hemicentrotus pulcherrimus by gel filtration and tested for ability to induce the acrosome reaction in H. pulcherrimus spermatozoa with or without exogenously added synthetic speract. The macromolecular fraction without speract showed only about half the activity of the original unfractionated jelly for induction of the acrosome reaction. The rates of the acrosome reaction induced by the fraction with speract were comparable with those induced by the unfractionated jelly at all pHs tested. Speract itself, however, did not induce the acrosome reaction in the absence of the macromolecular fraction of jelly. The acrosome reaction was associated with incerase of the cyclic AMP concentration in sperm cells, the extent of incerase depending on the concentration of the macromolecular fraction. Addition of speract to the fraction enhanced both induction of the acrosome reaction and increase in the cyclic AMP concentration induced by the fraction. These results suggest that a major factor(s) responsible for the acrosome reaction is a macromolecular component(s) of the jelly and that speract promotes the reaction as a co-factor.     

The Prosencephalon Has the Capacity to Differentiate into the Optic Tectum: Analysis by Chick-Specific Monoclonal Antibodies in Quail-Chick-Chimeric Brains

The alar plate of the prosencephalon of the quail embryo was heterotopically transplanted into the alar plate of the mesencephalon of the chick embryo at the 7–10 somite stage. Chick and quail cells in chimeric brains were distinguished after Feulgen-Rossenbeck staining and/or immunohistochemical staining with a species specific monoclonal antibody MAb-37F5 which recognized cytoplasmic components of chick brain cells. Neural connections between the transplant and the host were studied by monoclonal antibodies, MAb39-B11, which recognizes a species specific antigen on chick nerve fibers, and MAb-29B8, which reacts to 160 kD neurofilaments of both chick and quail.
When the transplant was completely integrated into the host mesencephalon, the transplant developed a laminar morphology closely resembling that of the optic tectum. Immunohistochemical staining with MAb-39B11 showed that the host optic nerve fibers innervated both the host tectum and the tectum-like transplant. However, optic nerve fibers did not invade transplants that failed to develope a laminar structure characteristic of the tectum. These findings suggest that the prosencephalon has a capacity to differentiate into the optic tectum at the 7–10 somite stage.     

INDUCTION OF ASTER FORMATION AND CLEAVAGE IN EGGS OF THE SEA URCHIN HEMICENTROTUS PULCHERRIMUS BY INJECTION OF SPERM COMPONENTS*

Studies were made on which components of sperm were able to induce aster formation and cleavage of eggs of the sea urchin Hemicentrotus pulcherrimus. The sperm components were separated by homogenization and centrifugation into the following 3 fractions: the head-midpiece, midpiece and tail. The head-midpiece fraction was then divided into 2 sub-fractions, the centriole sub-fraction and the centriole-free sub-fractions. Each fraction was injected into unfertilized eggs and after 15–30 min the eggs were inseminated. The ability of a fraction or a sub-fraction to induce aster formation and cleavage was deduced from the frequency of multipolar cleavage. The head-midpiece fraction and the centriole sub-fraction were effective in inducing aster formation and cleavage, but the other fractions were not. It was concluded that isolated centrioles from sea urchin sperm act as division centers in the egg.