The Influence of a High‐Fat Dietary Environment in the Fetal Period on Postnatal Metabolic and Immune Function

Few reports show whether a high‐fat (HF) dietary environment in the fetal period affects immune function or the development of lifestyle‐related disease at maturity. We examined the influence of an HF dietary environment in the fetal period on postnatal metabolic and immune function. A total of 16 pregnant mice were given control (CON) diet and 16 were given HF diet in the gestational period, from mating to delivery. After delivery lactating mice were given either CON or HF diet, resulting in four groups. After weaning, the offspring mice were given the same diet that their mothers received during lactation. HF dietary intake in the postnatal period increased fat pad weights, serum glucose, and leptin levels. An HF diet in the fetal period resulted in fewer splenic lymphocytes, a thinner thymic cortex, and impaired antigen‐specific immune reactions. Furthermore, tumor necrosis factor (TNF)‐α production and serum triglyceride levels were elevated in the fetal HF group. In addition, the HF‐HF group showed a consistent decrease in ovalbumin (OVA)‐specific IgG and elevation of IgE, associated with advanced fatty changes in the liver. Results from this study suggest that HF environment during the fetal period induces epigenetic propensity toward obesity and immunological burden in part due to increased adipose tissue mass, significant reduction in the number of immune cells and decreased activities of immune cells.     

Stabilization of the fibrous structure of an alpha-helix-forming peptide by sequence reversal

The alpha3-peptide, which comprises three repeats of the sequence Leu-Glu-Thr-Leu-Ala-Lys-Ala and forms an amphipathic alpha-helix, is unique among various alpha-helix-forming peptides in that it assembles into fibrous structures that can be observed by transmission electron microscopy. As part of our investigation of the structure-stability relationships of the alpha3-peptide, we synthesized the r3-peptide, whose amino acid sequence is the reverse of that of the alpha3-peptide, and we investigated the effects of sequence reversal on alpha-helix stability and the formation of fibrous structures. Unexpectedly, the r3-peptide formed a more-stable alpha-helix and longer fibers than did the alpha3-peptide. The stability of the r3-peptide helix decreased when the ionic strength of the buffer was increased and when the pH of the buffer was adjusted to 2 or 12. These results suggest that the r3-peptide underwent a "magnet-like" oligomerization and that an increase in the charge-distribution inequality may be the driving force for the formation of fibrous structures.     

Cooperation of ER-60 and BiP in the oxidative refolding of denatured proteins in vitro

ER-60 is a PDI family protein that has protein thiol-disulfide oxidoreductase activity. It has been shown to associate with BiP in the endoplasmic reticulum. Here, we analyzed the cooperation of ER-60 and BiP in the oxidative refolding of denatured proteins in vitro. ER-60 facilitated the refolding of 20 or 30% of denatured alpha-lactalbumin or ribonuclease B during incubation for 80 min, and these levels of nearly doubled on the addition of BiP to the reaction mixture. BiP alone could not refold denatured ribonuclease B, but could refold denatured alpha-lactalbumin a little. Enhancement of oxidative refolding of alpha-lactalbumin by ER-60 could be detected only when ER-60 was present from the start of refolding. On surface plasmon resonance analysis, ER-60 was shown to associate with BiP. The association was not influenced by ATP or ADP. Domains a and/or b' of ER-60 were implicated in the association with BiP.     

Effect of vitamin B12-enriched thraustochytrids on the population growth of rotifers

Newly isolated thraustochytrids showed uptake of vitamin B12 from the culture into the cells. Cultivation of thraustochytrids in a medium containing 1 microg/ml of vitamin B12 greatly increased the contents of vitamin B12 in the cells. Similarly to Schizochytrium limacinum, odd numbered fatty acids decreased in the cells of new isolates cultivated with vitamin B12. Vitamin B12-enriched thraustochytrids, strain mh0186, enhanced the population growth of rotifers fed on the cells as sole feed.     

Skeletal isotope microprofiles of growth perturbations in<Emphasis Type="Italic"> Porites</Emphasis> corals during the 1997–1998 mass bleaching event

Severe coral bleaching occurred throughout the tropics in 1997/98. We report high-resolution skeletal oxygen isotope (¹⁸O) and carbon isotope (¹³C) microprofiles for bleached corals from Pandora Reef, Great Barrier Reef, and Ishigaki Island, Japan, in order to examine the ability of Porites corals to record clear signals of bleaching. Analysis of the annual cycle in ¹⁸O revealed abrupt reductions in skeletal extension immediately after the 1997–98 summer temperature maximum, indicating that bleaching inhibits coral calcification. Skeletal ¹³C in the Ishigaki corals showed lower values during bleaching, indicating depressed coral metabolism associated with a reduction in calcification. In contrast, microprofiles of skeletal ¹³C from the shaded sides of Pandora Reef corals exhibited little change, possibly because algal photosynthesis was already slow prior to bleaching, thus subduing the ¹³C-response to bleaching. Comparison of ¹⁸O microprofiles from bleached corals with instrumental temperature records showed that Porites corals can recover following 5 months with little skeletogenesis. The results indicate that isotopic microprofiling may be the key to identifying gaps in coral growth that are diagnostic of past bleaching events. We have tested this hypothesis using blue UV fluorescent bands to guide us to coral skeleton where isotope microprofiling identifies bleaching events in 1986, 1989, and 1990. These events, detected by proxy, suggest that coral bleaching may have occurred more commonly on Ishigaki Island than previously recorded.     

Low maternal licking/grooming stimulation increases pain sensitivity in male mouse offspring

Deprivation of maternal care has been associated with higher pain sensitivity in offspring. In the present study, we hypothesized that the maternal licking/grooming behavior was an important factor for the development of the pain regulatory system. To test this hypothesis, we used male F2 offspring of early-weaned (EW) F1 mother mice that exhibit lower frequency of licking/grooming behavior. The formalin test revealed that F2 offspring of EW F1 dams showed significantly higher pain behavior than F2 offspring of normally-weaned (NW) F1 dams. We found that the mRNA levels of transient receptor potential vanilloid 1 (TRPV1), a nociceptor, were higher in the lumbosacral dorsal root ganglion (DRG) of F2 offspring of EW F1 dams than those of F2 offspring of NW F1 dams, suggesting that the higher pain sensitivity may be attributed to low licking/grooming, which may result in developmental changes in nociceptive neurons. In the DRG, mRNA levels of Mas-related G-protein coupled receptor B4 (MrgprB4), a marker of sensory neurons that detect gentle stroking, was also up-regulated in the F2 offspring of EW F1 dams. Considering that gentle touch alleviates pain, Mrgprb4 up-regulation may reflect a compensatory change. The present findings indicate important implications of maternal licking/grooming behavior in the development of the pain regulatory system.     

Complete Nucleotide Sequences of Virulence-Resistance Plasmids Carried by Emerging Multidrug-Resistant Salmonella enterica Serovar Typhimurium Isolated from Cattle in Hokkaido,Japan

In the present study, we have shown that virulence-resistance plasmids from emerging multidrug-resistant isolates of Salmonella enterica serovar Typhimurium were derived from a virulence-associated plasmid, essential for systematic invasiveness of S. Typhimurium in mice (pSLT), through acquisition of a large insert containing a resistance island flanked by IS1294 elements. A bla _CMY-2-carrying plasmid from a cefotaxime-resistant isolate comprised a segment of Escherichia coli plasmid pAR060302 and the replication region (IncFIB) of a virulence-resistance plasmid. These results provide insights into the evolution of drug resistance in emerging clones of S. Typhimurium.