Areolae of the Placenta in the Antarctic Minke Whale (Balaenoptera bonaerensis)

In this study, we examined the existence and structure of areolae and the steroidogenesis of areolar trophoblast cells in the Antarctic minke whale placenta morphologically and immunohistochemically. Placentas were collected from the 15th, 16th and 18th Japanese Whale Research Program under Special Permit in the Antarctic (JARPA) and 1st JARPA II organized by the Institute of Cetacean Research in Tokyo, Japan. The opening and cavity of fetal areolae formed by taller columnar trophoblast cells (areolar trophoblast cells) with long microvilli and a bright cytoplasm, as compared with the trophoblast cells of the chorionic villi interdigitating with the endometrial crypts, were recognized in observations of serial sections. The opening of the areolar cavity was hidden by chorionic villi with areolar trophoblast cells. Furthermore, a closed pouch-like structure lined by tall columnar cells similar to areolar trophoblast cells within the stroma of chorionic villi was noticed and continued to the areolar cavity, with the opening seen on serial sections. In a surface investigation of the chorion and endometrium by SEM, maternal (endometrial) areolae irregularly surrounded by endometrial folds were obvious. Moreover, we distinguished areolar trophoblast cells with long microvilli attached with many blebs from trophoblast cells. In our immunohistochemical observations, a steroidogenic enzyme, cytochrome P450 side chain cleavage enzyme (P450scc), was detected with strong immunoreactivity in trophoblast cells. However, areolar trophoblast cells showed weak or no immunoreactivity for P450scc.     

Metal nanotubule membranes with electrochemically switchable ion-transport selectivity

Membranes containing cylindrical metal nanotubules that span the complete thickness of the membrane are described. The inside radius of the nanotubules can be varied at will; nanotubule radii as small as 0.8 nanometer are reported. These membranes show selective ion transport analogous to that observed in ion-exchange polymers. Ion permselectivity occurs because excess charge density can be present on the inner walls of the metal tubules. The membranes reject ions with the same sign as the excess charge and transport ions of the opposite sign. Because the sign of the excess charge on the tubule can be changed potentiostatically, a metal nanotubule membrane can be either cation selective or anion selective, depending on the potential applied to the membrane.     

Introduction of a point mutation in the KRAS gene of in vitro fertilized porcine zygotes via electroporation of the CRISPR/Cas9 system with single-stranded oligodeoxynucleotides

This study aimed to investigate the efficiency of KRAS gene editing via CRISPR/Cas9 delivery by electroporation and analyzed the effects of the non-homologous end-joining pathway inhibitor Scr7 and single-stranded oligodeoxynucleotide (ssODN) homology arm length on introducing a point mutation in KRAS. Various concentrations (0–2 µM) of Scr7 were evaluated; all concentrations of Scr7 including 0 µM resulted in the generation of blastocysts with a point mutation and the wild-type sequence or indels. No significant differences in the blastocyst formation rates of electroporated zygotes were observed among ssODN homology arm lengths, irrespective of the gRNA (gRNA1 and gRNA2). The proportion of blastocysts carrying a point mutation with or without the wild-type sequence and indels was significantly higher in the ssODN20 group (i.e., the group with a ssODN homology arm of 20 bp) than in the ssODN60 group (gRNA1: 25.7% vs. 5.4% and gRNA2: 45.5% vs. 5.9%, p < .05). In conclusion, the CRISPR/Cas9 delivery with ssODN via electroporation is feasible for the generation of point mutations in porcine embryos. Further studies are required to improve the efficiency and accuracy of the homology-directed repair.     

Abnormal functions of Leydig cells in crossbred cattle–yak showing infertility

In Mongolia, yak (Bos grunniens) are able to live in alpine areas and their products greatly influence the lives of the local people. Increased vigour in hybridized yak and cattle can offer benefits for livestock farmers. However, male hybrids show reproductive defects resulting from spermatogenesis arrest, affecting the conservation and maintenance of dominant traits in the next generation. The underlying mechanisms involved in hybrid cattle–yak infertility have recently been investigated; however, the genetic cause is still unclear. Androgens and androgen receptor (AR) signalling are required for spermatogenesis. We, therefore, evaluated the expression of AR, 3β-hydroxysteroid dehydrogenase (3βHSD) and 5α-reductase 2 (SRD5A2) in Leydig cells to investigate their function in cattle–yak spermatogenesis. Testicular tissues from yaks (1–3 years old) and hybrids (F1–F3, 2 years old) were collected and subjected to immunohistochemistry and image analyses to investigate the expression of each parameter in the Leydig cells. After maturation at 2 years, the expression levels of AR increased and the levels of 3βHSD decreased, but the SRD5A2 levels remained constant in yak. However, the cattle–yak hybrid F2 showed immature testicular development and significantly different expression levels of AR and 3βHSD compared with mature yak. These results suggest that the decreased expression of AR and increased expression of 3βHSD in the Leydig cells of cattle–yak hybrid testes may represent one of the causes of infertility. Our study might help in solving the problem of infertility in crossbreeding.     

Comparison of extractive components in muscle and liver of three Loliginidae squids with those of one Ommastrephidae species

Extractive components were determined for the mantle muscle and liver of three species of Loliginidae squid, Sepioteuthis lessoniana, Loligo bleekeri, and L. edulis, and one species of Ommastrephidae, Todarodes pacificus, as a control. Total free amino acid levels and the major free amino acids in muscle, taurine, proline, glycine, alanine, and arginine, were significantly higher in Loliginidae squids than in T. pacificus. The main nucleotide was adenosine 5′-monophosphate, which did not differ significantly between species. Malate was the organic acid found in muscle in highest concentrations. The muscle of these species contained a large amount of trimethylamine oxide. A large amount of glycine betaine was also detected in the muscle, but showed no large species difference. From these results, the muscle of Loliginidae species is considered to have a much sweeter taste than that of T. pacificus. Compared with muscle, squid liver was characteristic with high contents of taurine, glutamate, bitter amino acids, succinate, propionate, trimethylamine, and glycine betaine, and with low contents of sweet amino acids, arginine, nucleotides, malate, and trimethylamine oxide. These results suggest that squid liver is characterized by a complicated taste containing umami, bitterness, sourness, fishy flavor, and less sweetness.     

Two species of seabirds foraged in contrasting marine habitats across the cold-water belt along the coast of northern Hokkaido in the southwestern Okhotsk Sea

To understand the environmental factors affecting the density of foraging seabirds across the cold-water belt in the southwestern Okhotsk Sea, we conducted a 1-day (180-km transect length) shipboard seabird survey off the northeastern coast of Hokkaido during summer in 2019, along with acoustic observations of potential prey (zooplankton and fish) biomass, thermosalinograph measurements, and CTD observations. Planktivorous short-tailed shearwaters Ardenna tenuirostris (66% of total seabirds) and piscivorous rhinoceros auklets Cerorhinca monocerata (28%) were predominant, but foraged in contrasting habitats. A large foraging flock of shearwaters was observed in the cold-water belt zone, including its front with coastal Soya Warm Current Water and the offshore Fresh Surface Okhotsk Sea Water, where surface chlorophyll a concentrations were the highest but not related to their prey (zooplankton) biomass at any spatial scale between 4.6 and 9.2 km. In contrast, the density of auklets was high in the coastal Soya Warm Current Water, where the acoustically determined fish biomass was large, and showed a positive relationship with the fish biomass especially in the lower layer (29–104 m depth) at any spatial scale. This species-specific difference in response to prey biomass might be related to prey-searching behaviors; i.e., rhinoceros auklets search prey underwater visually, but short-tailed shearwater can use both visual and olfactory cues to locate zooplankton patches from the air.

     

Efficiency of the indirect selection and the evaluation of the genotype by environment interaction using Pilodyn for the genetic improvement of wood density in <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

The efficiency of the indirect selection for wood density using the Pilodyn in Cryptomeria japonica was studied by comparing the Pilodyn penetration (PP) depth and the direct measurement of wood density in three test sites. The influence of the genotype by environment (G × E) interaction of wood density was estimated using the Pilodyn with common 12 C. japonica clones in 10 test sites in Kanto breeding region in Japan. The PP depth was highly correlated with wood density, and the genetic correlation between them was −0.88. The indirect selection using the Pilodyn realized 87% of the genetic gain obtained by the direct selection of wood density. The G × E interaction in PP depth was small. The ratio of the variance component of the G × E interaction to that of genotype was only 0.096 in the PP depth, whereas it was 0.700 in tree height and 1.410 in diameter at breast height. These findings indicate that the Pilodyn is useful for the genetic improvement of wood density in Cryptomeria japonica. The small G × E interaction in wood density estimated using the Pilodyn indicates that the relative clonal performance in wood density is stable among diverse environments in Kanto breeding region in Japan.