Impact of short-term high-fat feeding on lipid droplet content in mouse oocytes

Mature mammalian oocytes contain lipid droplets (LDs), which are neutral lipid storage organelles critically important for energy metabolism. In mice, maternal obesity, induced by long-term (> 3 months) high-fat feeding, contributes to the accumulation of LDs in mature oocytes. However, few studies have investigated the influence of short-term high-fat feeding on LD content. In this study, we demonstrated that 3 weeks of high-fat feeding is sufficient to increase LD content and intracellular triacylglycerol levels. Using a two-step centrifugation technique to release LDs into the perivitelline space, we found that short-term high-fat feeding increased the level of LDs in MII oocytes and that 3 days of high-fat feeding were sufficient to increase efficiency of LD release. Collectively, our study suggests that short-term high fat feeding can have a higher impact on lipid metabolism during oocyte maturation.     

Application of laser-assisted zona drilling to in vitro fertilization of cryopreserved mouse oocytes with spermatozoa from a subfertile transgenic mouse

Development of assisted reproductive technologies is necessary to obtain fertilized oocytes in a subfertile transgenic mouse strain. Here, we showed the application of laser-assisted drilling of the zona pellucida to in vitro fertilization of cryopreserved mouse oocytes with sperm from subfertile transgenic mice (C57BL/6N-Tg(UCP/FAD2)U8 strain). After cryopreservation by vitrification, the recovery and survival rates of the zona-drilled mouse oocytes were 97% (97/100) and 94% (91/97), respectively. In vitro fertilization of the cryopreserved zona-drilled mouse oocytes with sperm from the subfertile transgenic mice was greatly facilitated (60%, 55/91) compared to that of the cryopreserved zona-intact mouse oocytes (11%, 81/768). In vitro fertilized embryos that developed to the 2-cell stage were again cryopreserved by vitrification, and after warming they were transferred into recipient females. Subsequently, six viable offspring were delivered, and all were confirmed to be transgenic mice. These results indicate that laser-assisted zona drilling of oocytes combined with cryopreservation by vitrification may be a useful approach for large-scale production of in vitro fertilized embryos for managing transgenic mouse strains with reproductive disabilities such as subfertile sperm.     

Comparison of 3 different reinforcements of learning in dogs (Canis familiaris)

Effective dog training involves reinforcement of the dog's correct actions in response to specific cues given by the trainer. Food is usually selected as the primary reinforcer (reward), although this selection does not necessarily account for the learning preferences of individual dogs. We evaluated the relationship between reward and learning efficiency. Fifteen dogs were allocated to 3 different reward groups (food, stroking, and praise) and trained by an identical process. The food reward was the only one that shortened the time taken for the response to the command to be completed. However, this difference occurred only in the early training stages and not later in the training process.     

Comparison of enzyme activities in plasma and leukocytes in dairy and beef cattle

Concentrations of plasma glucose, immunoreactive insulin (IRI) and free fatty acid (FFA) and activities of enzymes related to energy metabolism and lactate dehydrogenase (LDH) isoenzyme pattern in plasma and leukocytes were investigated in lactating Holstein cows (dairy cattle) and fattening Japanese Black Wagyu x Holstein steers (beef cattle). IRI concentrations and LDH and malate dehydrogenase (MDH) activities in the plasma of beef cattle were significantly higher than those in dairy cattle. The cytosolic ratio of MDH/LDH activity in the leukocytes of beef cattle was significantly higher than that of dairy cattle. These findings might be associated with the different energy metabolism between dairy and beef cattle.     

Inosine‐5'‐monophosphate is a candidate agent to resolve rigor mortis of skeletal muscle

The object of the present study was to reveal the action of inosine‐5'‐monophosphate (IMP) toward myofibrils in postmortem muscles. IMP solubilized isolated actomyosin within a narrow range of KCl concentration, 0.19‐0.20 mol/L, because of the dissociation of actomyosin into actin and myosin, but it did not solubilize the proteins in myofibrils with 0.2 mol/L KCl. However, IMP could solubilize both proteins in myofibrils with 0.2 mol/L KCl in the presence of 1 m mol/L pyrophosphate or 1.0–3.3 m mol/L adenosine‐5'‐diphosphate (ADP). Thus, we presumed that pyrophosphate and ADP released thin filaments composed of actin, and thick filaments composed of myosin from restraints of myofibrils, and then both filaments were solubilized through the IMP‐induced dissociation of actomyosin. Thus, we concluded that IMP is a candidate agent to resolve rigor mortis because of its ability to break the association between thick and thin filaments.     

Anaphylaxis after rabies vaccination for dogs in Japan

Severe adverse reactions after rabies vaccination in dogs were examined from 317 cases reported to the Ministry of Agriculture, Forestry and Fisheries (MAFF) in Japan during 15-year period from April 2004 to March 2019. We found that 109 of the 317 dogs showed anaphylaxis (0.15/100,000 vaccinated dogs), and 71 of the 109 cases of anaphylaxis resulted in death (0.10/100,000 vaccinated dogs). We measured bovine serum albumin (BSA) in four commercially available rabies vaccines and found the levels ranged from 0.1 to 16.6 µg/dose. Our survey showed that the rate of anaphylaxis to rabies vaccines in dogs is rare, although some cases of anaphylaxis resulted in death. Veterinarians should be well prepared to deal with vaccine-associated anaphylaxis.     

Purification and Characterization of Cathepsin B from the Muscle of Horse Mackerel Trachurus japonicus

An endogenous protease in fish muscle, cathepsin B, was partially purified and characterized from horse mackerel meat. On SDS-PAGE of the purified enzyme under reducing conditions, main protein bands were detected at 28 and 6 kDa and their respective N-terminal sequences showed high homology to heavy and light chains of cathepsin B from other species. This suggested that horse mackerel cathepsin B formed two-chain forms, similar to mammalian cathepsin Bs. Optimum pH and temperature of the enzyme were 5.0 and 50 °C, respectively. A partial cDNA encoding the amino acid sequence of 215 residues for horse mackerel cathepsin B was obtained by RT-PCR and cloned. The deduced amino acid sequence contains a part of light and heavy chains of cathepsin B. The active sites and an N-glycosylation site were conserved across species. We also confirmed that the modori phenomenon was avoided by CA-074, a specific inhibitor for cathepsin B. Therefore, our results suggest that natural cysteine protease inhibitor(s), such as oryzacystatin derived from rice, can apply to thermal-gel processing of horse mackerel to avoid the modori phenomenon. Meanwhile, this endogenous protease may be used for food processing, such as weaning meal and food for the elderly.     

Radial variations of wood properties in <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis> growing in Bangladesh

Radial variations of wood properties (basic density, fiber length, vessel element length, and compression strength) in plantation-grown Casuarina equisetifolia in Bangladesh were investigated for effective utilization of the wood. Samples disks at breast height were randomly collected from trees in a 10-year-old plantation in Cox’s Bazar Forest Division, Bangladesh. The basic density showed a near-constant value up to 30 mm from the pith and then rapidly increased up to 60 mm from the pith. The fiber length and vessel element length gradually increased from the pith to bark. When radial variation of wood properties was determined according to relative distance from the pith, similar radial patterns were observed among the sample trees, indicating that the wood properties in C. equisetifolia may be related to the growth rate. The compression strength parallel to the grain (CS) increased from the pith to bark. A significant positive correlation was found between the air-dried density and the CS. The results obtained indicated that wood around the pith has a relatively low density, and wood outside the pith area has a relatively high density, suggesting that it could be used as structural lumber. Part of this report was presented at the 58th Annual Meeting of Japan Wood Research Society, Tsukuba, March 2008     

Effect of row type,flowering type and several other spike characters on resistance to Fusarium head blight in barley

Fusarium head blight (FHB) is a destructive disease of barley. The genetics and expression of resistance to FHB in barley is complex, and various spike characters are thought to possibly influence resistance. Tests using spray-inoculation of Fusarium graminearum at anthesis in greenhouse environments showed that two-rowed and cleistogamous varieties from Japan belong to the highest resistance group, while six-rowed and chasmogamous varieties are mostly susceptible. In order to evaluate the effect of such spike characters, including row type and flowering type, on FHB resistance, near-isogenic lines (NILs) differing in these characters were tested for their resistance. Two testing methods were used: the pot-plant and cut-spike methods, in which spikes at anthesis were spray-inoculated in greenhouse environments. The chasmogamous NILs and some six-rowed NILs were significantly more diseased than cleistogamous and two-rowed parent lines, respectively, and the difference in FHB severity was greater and more stable between cleistogamous/chasmogamous NIL pairs than between two-/six-rowed pairs. Slight or no differences were observed in glaucous/non-glaucous, normal/dense spike, normal/uzu type and normal/deficiens NIL pairs. The results indicate that the contribution of cleistogamy and/or the genetic background toward FHB resistance is more than that of row type and the other tested spike characters. Further, it should be possible to develop six-rowed varieties with FHB resistance nearly as good as that of the two-rowed varieties.     

Genotypic Variation in Shoot Cadmium Concentration in Rice and Soybean in Soils with Different Levels of Cadmium Contamination

A pot experiment was conducted to investigate whether the shoot cadmium (Cd) concentration in 11 rice and 10 soybean cultivars varied among 4 soils with different levels of Cd contamination. Significant differences in shoot Cd concentration were found among rice or soybean cultivars grown in the 4 soils. The ranking of the rice cultivars for the shoot Cd concentration varied considerably among the soils. On the other hand, the soybean cultivars were ranked similarly in terms of shoot Cd concentration in the 4 soils. Significant and positive correlations were found between the Cd and Zn concentrations and between the Cd and Mn concentrations in the shoot of rice cultivars, when they were grown in 2 soils with relatively moderate levels of Cd contamination. The shoot Cd concentration in the soybean cultivars, however, was not correlated with the concentrations determined for any of the metals (Zn, Mn, Cu, and Fe) across the 4 soils. Significant and positive correlations between the concentrations of Cd in younger shoots and mature seeds were detected among the soybean cultivars in 2 soils used, unlike among the rice cultivars, indicating that it may be difficult to evaluate the genotypic variation in seed Cd concentration using relatively younger shoots in the case of rice. These results revealed that genotypic differences in shoot Cd concentration in rice or soybean are variable or invariable among soils, respectively.