Retinal topography of ganglion cells in immature ocean sunfish, <Emphasis Type="Italic">Mola mola</Emphasis>

The ocean sunfish, Mola mola, is the largest known bony fish. Based on prior studies of diet composition, it is considered to be a pelagic zooplanktivore. However, a recent study using acoustic telemetry revealed that they repeatedly dive to depths of >50 m during the day. We examined the distribution of cells within the retinal ganglion cell layer in the immature ocean sunfish (c.a. 50 cm total length) and estimated their visual acuity with respect to the main visual axis and visual fields. Visual acuity was between 3.37 and 4.41 cycles/degree. The region of highest cell density was located in the dorso-temporal retina, indicating that the main visual axis of ocean sunfish is directed towards the lower frontal portion of the visual field. This axis is considered beneficial for detecting prey items when the sunfish are migrating vertically through the water column, and in foraging behavior near the sea bottom.     

The phylogenetic position of an undescribed paedomorphic clupeiform taxon: mitogenomic evidence

Molecular characters may offer a useful alternative to confidently estimate the phylogenetic position of paedomorphic taxa otherwise difficult to place based on morphology because of the reduction or absence of characters in their larvae-like adult stage. Here, we sequenced the complete mitogenome of a remarkable undescribed marine paedomorphic clupeiform fish to gain insight into its phylogenetic position. Of a length of 17,507 bp, this mitogenome exhibits a unique gene order within the Teleostei because of the inversion of the contiguous tRNA^Gln and tRNA^Ile within the IQM region and the presence of a putative second control region inserted between these tRNAs. Mitogenomic data from 27 clupeiform species and 22 non-clupeiform species were subjected to partitioned maximum likelihood and Bayesian analyses. All resultant phylogenetic trees strongly supported the placement of this undescribed taxon within the order Clupeiformes, suborder Clupeoidei, and the family Clupeidae, as the sister group of the tribe Spratelloidini (Jenkinsia + Spratelloides) of the subfamily Dussumieriinae. Together, they form a monophyletic group with Chirocentrus and, possibly, Etrumeus. Despite its overall resemblance to Sundasalanx, this undescribed taxa (Clupeidae gen. et sp. indet.) is not closely related to that genus and represents an independent paedomorphic lineage within the Clupeoidei. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Antidiabetic effect of Lactobacillus GG in streptozotocin-induced diabetic rats

Neonatally streptozotocin-induced diabetic (n-STZ) rats were given food containing Lactobacillus GG cells (GG) or a control diet (control), from 9 to 18 weeks of age. The GG cells significantly lowered the blood hemoglobin A(1C) (HbA(1C)) level and improved glucose tolerance in n-STZ rats (p<0.05). In the GG group, the serum insulin level at 30 min after glucose loading was significantly higher than in the control group (p<0.05).     

Accumulation pattern of arachin and its subunits in maturation of groundnut seeds

The accumulation pattern of arachin and its subunits in growinggroundnuts was investigated. Soluble proteins were extractedfrom the kernels at twelve different stages of maturation (4–16weeks after pegging). Fractionation showed arachin, conarachinII, 5S and 2S protein components with sucrose gradient centrifugation.Ten weeks after pegging, only 35% of the maximum amount of arachinhad accumulated, whereas conarachin II was 85%, the 5S component89%, and the 2S component 76%. Arachin, however, increased rapidlyin the later stage of maturation. No change in the subunit ratioin arachin during seed growth was observed on the patterns ofsodium dodecyl sulfate-gel electrophoresis and gel isoelectricfocusing in the presence of urea. The ratio of the arachin subunitscontained in urea-extractable fraction of the kernels was constantthroughout seed development and was consistent with the subunitratio in arachin. On the other hand, the arachin subunits inthe free forms, if any, accounted for less than 1% of the associatedarachin subunits. Probably, the arachin subunits synthesizedin equimoles are associated into arachin without individualdeposition and are accumulated as arachin associates in growingseeds. (Received July 17, 1980; )     

Does egg dispersal occur via the ocean in the stick insect Megacrania tsudai (Phasmida: Phasmatidae)?

Although insects expand their distribution by various ways, generally only the adult phase has been taken into consideration in research on dispersal. In Megacrania tsudai, it has been proposed that eggs are dispersed through seawater. To test this hypothesis, eggs were treated under normal condition (NC) on wet cotton swabs, and marine condition (MC), floating on salt water for 30, 60, 90, and 365 days. In addition, eggs in the NC and MC treatment groups were dissected every 10 days to verify the developmental stage. The hatching rates in the NC and MC treatment groups were not significantly different among the five treatment groups. However, the egg period, time from laying to hatching, in the MC treatment group was significantly longer than that in any other treatment groups. The egg period was lengthened when the floating period on seawater was longer. The time of the start of egg development was similar in the NC and MC treatment groups, but the developmental speed was slower in the MC treatment group. These results support that M. tsudai can expand its distribution by dispersing its eggs through seawater, probably thanks to specific characteristics of eggs that allow their survival when they float in the sea.