Ultrastructure of gonadotropic cells of the normal eel and after estradiol injection]

Male and female silver eels, in fresh water or sea water, have few gonadotrophs (GTH) poorly differentiated. An oestradiol (E2) treatment induces their development: a well developed Golgi area, abundant secretory granules (200-500 nm), dilated cisterna and large globules 1.2-2.2 micron) are observed. A positive feedback may control gonadotropin synthesis in immature eels. No macroscopic effect is discernible on the gonad.     

Distribution of 4-iodine-antipyrine (I131) in the rat

Resumen La determinación de agua total y de agua tisular se efectuo por medio de la dilución de 4-yodo-antipirina (I¹³¹) en la rata. Los resultados obtenidos muestran que la distribución regional del indicador no es similar a la del agua, aunque el volumen de agua total encontrado se aproxima a los valores medios normales. Esta distribución del indicador en los tejidos no hace aconsejable la utilización de este indicador para la medición del volumen de agua total o regional.     

Ultrastructure and biochemistry of the pineal organ in deep-sea lanternfishes (Myctophidae)

Summary Pineal structural and biochemical adaptations in lanternfishes included: 1) few photoreceptor outer segment discs; 2) conventional synapses between photoreceptors and pineal neurons; and 3) low levels (0–60 pg/pineal) of serotonin compared to those (>1.0 ng/pineal) in the goldfish pineal organ. These findings suggest reduced photosensory and/or neuroendocrine functions in these deep-sea fishes.     

Ultrastructure and biochemistry of the pineal organ in deep-sea lanternfishes (Myctophidae)

Pineal structural and biochemical adaptations in lanternfishes included: 1) few photoreceptor outer segment discs; 2) conventional synapses between photoreceptors and pineal neurons; and 3) low levels (0-60 pg/pineal) of serotonin compared to those (greater than 1.0 ng/pineal) in the goldfish pineal organ. These findings suggest reduced photosensory and/or neuroendocrine functions in these deep-sea fishes.     

On combined effects of deoxyfluorouridine (FUDR) with radiations and ethyl methane sulphonate (EMS) on chromosomes

Résumé Des graines deNigella damascena et des graines d'orge ont été irradiés par les rayons du Co⁶⁰ ainsi que par des neutrons rapides. Ils ont ensuite été traités par la déoxyfluorouridine (FUDR) après différents temps de prégermination. On a observé que FUDR accroissait de manière nette les effets totaux des rayons sur les chromosomes (taux d'aberrations en anaphase). Par contre les effets des neutrons rapides n'ont été que faiblement modifés. Des effets synergiques ont également été obtenus chez l'orge après des traitements consécutifs FUDREMS.     

Ultrastructure of 30–40 million year old leaflets from Dominican amber (Hymenaea protera,Fabaceae: Angiospermae)

Hymenaea protera leaflet fossils entombed in amber, dated at 30 to 40 million years (mine strata and exomethylene dating) were observed by both light and transmission electron microscopy. Ultrastructure preservation in these leaflets shows the presence of chloroplasts with thylakoid membranes, cell walls, mitochondria with associated endoplasmic reticulum, nuclei, and xylem tissue. Tissues show varying degrees of degradation; however, natural resin, which has perfused the cells, seems to maintain the structural integrity of the membranes and walls. We conclude that preservation of amber entombed organisms results from dehydration and slow fixative properties leaving the ultrastructure in excellent condition. These findings parallel reports on the exceptional preservation of amino acids and of DNA in amber-entombed organisms.     

Chiasmate type of meiosis in the roachNauphoeta cinerea (Oliver) (Fam: Blattidae)

Résumé Nauphoeta cinerea est un des Cafards chez lesquels le chiasma de la méiose a été nettement observé. Ce cas vient à l'appui de l'assertion deSuomalainen selon laquelle des chiasmas se présenteraient sous une forme soit «cachée» soit «visible» chez tous les Cafards. La «méiose sans chiasma» queJohn etLewis supposent existes au moins chezP. americana n'est pas non plus confirmée par nos recherches.

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I wish to thank one of the research scholars of the Department, Mr. V. L.Kallapur, for sparing readily some specimens of the roach for my work. Constructive criticisms by my colleague Dr. R. M.Patil are also acknowledged.