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Squid embryos develop in the perivitelline fluid inside the chorion, which is an envelope secreted by the ovarian follicle. The onset of hatching initiates local dissolution of the chorion when the hatching gland enzyme facilitates the release of the developed paralarvae. In the present study, we investigated the pre-hatching behavioral patterns of Todarodes pacificus embryos and their responses to light after hatching. Observations of orientation were conducted using embryos developing inside chorions embedded within intact egg masses, while phototactic experiments were conducted on paralarvae that hatched from these egg masses. Within the restricted chorion and along the animal–vegetal axis, the embryos demonstrated a variety of orientation patterns that were categorized as swirls, glides, and somersaults. The contributions of these orientations to enhance oxygen diffusion and stimulate paralarval swimming immediately after hatching are discussed. Paralarvae exhibited normal diel vertical migration and responded positively to light sources. Vertical migration and phototaxis in T. pacificus paralarvae could have great adaptive significance because they hatch in neritic environments and are transported by ocean currents during their planktonic life. [ABSTRACT FROM AUTHOR]

AbstractIn vitrofertilization of squid requires the jelly substance found in the female oviducal gland; yet, the active component of this substance that facilitates fertilization remains unknown. Here, we used biochemical methods to separate the jelly substance of Todarodes pacificus(Oegopsida) and Sepioteuthis lessoniana(Myopsida family) into four fractions; specifically, two water soluble fractions (Molecular weight > 10,000 and < 10,000), one salt soluble fraction, and one insoluble fraction. The salt soluble fraction of T. pacificusinduced chorionic expansion (perivitelline space formation), which precedes the normal embryonic development of ova. In contrast, the salt soluble fraction of S. lessonianaelicited insufficient expansion of the ova, only producing embryos with high abnormality rates. These results suggest that the salt soluble component(s) (not the jelly-like substances) in the oviducal gland induce chorionic expansion and hatching in Oegopsida, and that these components may be similar in Myopsida.

The diet of Gonostoma gracile, a numerically abundant mesopelagic fish in the Subtropical Region and the Transition Domain of the northwestern North Pacific, was examined using 520 specimens collected during June–July 1988, June 1995 and November 1995. The prey included mainly copepods, ostracods, amphipods and euphausiids. Copepods and ostracods were the most abundant, comprising approximately 70% of the total diet. There was little evidence of an ontogenetic dietary shift; Pleuromammacopepods were the most abundant prey for all size classes of fish ranging from 19 to 116 mm in standard length. The size range of prey increased with growth, but all fish sizes examined fed mainly on 1–4 mm long prey. Luminescent copepods and ostracods were the most abundant prey, suggesting that G. graciledetects its prey visually.

Carbonylation of terminal alkynes was performed using a new triple catalytic system, Pd(II)/chlorohydroquinone/NPMoV, under carbon monoxide and oxygen. For instance, phenylacetylene was converted into methyl phenylpropiolate (85%) in methanol and phenylmaleic anhydride (62%) in dioxane. The reaction did not take place in the absence of oxygen.

Isophorone was smoothly oxidized with molecular oxygen by molybdovanadophosphate supported on the active carbon (NPMo V/C) to give 3-formyl-5,5-dimethyl-2-cyclohexen-1-one in relatively high selectivity. The regioselectivity of the oxidation by NPMo V/C was found to be just opposite to that of the conventional oxidations. The pore size of the supports appears to be an important factor governing the regioselectivity.

Cyclotrimerization of internal and terminal alkynes was performed using a new triple catalytic system, Pd(II)/chlorohydroquinone/NPMoV, under atmospheric oxygen. Internal alkynes such as 3-hexyne and 4-octyne were converted into hexaethyl- and hexapropylbenzenes in quantitative yields. Terminal alkyne, t-butylacetylene, afforded 1,3,5-tri- t-butylbenzene without formation of unsymmetrical tri- t-butylbenzenes. The reaction did not take place in the absence of oxygen.

Fertilizing capacity of spermatozoa collected from various storage sites in the male and female squids were examined by inseminated eggs in the presence or absence of gelatinous substances of the oviducal gland origin. Over 90% of the eggs were fertilized by the spermatozoa collected from the female's seminal receptacle regardless of the presence or absence of the gelatinous substance. Elevation of the chorion and the formation of perivitelline space was observed only in the jellied eggs. All jellyless eggs without perivitelline space died in 4 days after insemination. Spermatozoa collected from the spermatophore in the male's accessory gland could fertilize the majority of the eggs. On the other hand, those from the male's vas deferens could fertilize only 30-50% of both the jellied and jellyless eggs. It may be concluded from these experiments that the gelatinous substance of the oviducal gland origin has nothing to do with fertilization. However, it is essential for the elevation of the chorion and the formation of the perivitelline space. It may also be concluded that squid spermatozoa become fertile before they are transferred to the female's seminal receptacle.

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