Ostwald ripening of aqueous microbubble solutions.

Bubble solutions are of growing interest because of their various technological applications in surface cleaning, water treatment, and agriculture. However, their physicochemical properties, such as the stability and interfacial charge of bubbles, are not fully understood yet. In this study, the kinetics of radii in aqueous microbubble solutions are experimentally investigated, and the results are discussed in the context of Ostwald ripening. The obtained distributions of bubble radii scaled by mean radius and total number were found to be time-independent during the observation period. Image analysis of radii kinetics revealed that the average growth and shrinkage speed of each bubble is governed by diffusion-limited Ostwald ripening, and the kinetic coefficient calculated using the available physicochemical constants in the literature quantitatively agrees with the experimental data. Furthermore, the cube of mean radius and mean volume exhibit a linear time evolution in agreement with the Lifshitz-Slezov-Wagner (LSW) theory. The coefficients are slightly larger than those predicted using the LSW theory, which can be qualitatively explained by the effect of finite volume fraction. Finally, the slowdown and pinning of radius in the shrinkage dynamics of small microbubbles are discussed in detail.

Influence of broodmare aging on its offspring's racing performance.

Maternal aging has negative influences on the development and racing performance of their offspring in racehorses. However, the mechanism by which pregnancy at old age reduces the race performance of the offspring is unknown. Here, two hypotheses were posited: 1) Foals born to older mares are more likely to have muscular, skeletal, and cognitive disadvantages (direct effects). 2) Foals born to older mares are more likely to be affected by non-physiological factors correlating with the mare's age, such as the quality of sires (e.g. low-quality sires are likely to be chosen as partners of older broodmares). To test these hypotheses, the effect of the broodmare's age on the offspring's racing performance was examined, while controlling for the effects of the stallion's quality, age, and ID, offspring's sex, trainer, and the location of the training center. Information of racehorses registered to the Japan Racing Association were collected from the Japan Bloodhorse Breeders' Association website. Overall, results showed that the racing performance of horses born from older mares was lower than that of horses born from younger mares. However, generalized linear mixed models (GLMM) indicated that the quality of sires was significantly associated with the offspring's racing performance, rather than the broodmare's age itself. Furthermore, the age of broodmares was negatively correlated with the quality of sires, although the variance inflation factor was low. Therefore, the effect of maternal aging was negligible or only limited, and rather, the sire's quality had an important influence on the offspring's racing performance. Low quality sires, or cheap stallions in other words, are likely to be chosen as partners of older blood-mares, which may have reproductive risks such as lower fertility and higher rate of miscarriages. The present study suggests that the conventional belief that racehorses born from older mares show lower performance may not always be accurate.

Feral horses' (Equus ferus caballus) behavior toward dying and dead conspecifics.

In the rapidly expanding field of comparative thanatology, reports from a wide range of taxa suggest that some aspects of a concept of death may be shared by many non-human species. In horses, there are only a few anecdotal reports on behaviors toward dead conspecifics, mostly concerning domestic individuals. Here, we describe the case of a 2-month-old, free-ranging male foal that died around 12 h after being found severely injured due to a presumed wolf attack, focusing on other individuals' reactions to the dying foal. We also placed camera traps near horse carcasses to investigate reactions by other horses. Kin and non-kin of both sexes showed unusual interest in the dying foal. However, horses appeared to avoid dead conspecifics. Recording individual reactions to dead and dying conspecifics in naturalistic settings will enhance our knowledge about death-related behaviors in horses, allowing comparisons with other species that have been more thoroughly studied, to understand the evolutionary basis of these behaviors.

Complete Genome Sequences of Seven Peanut Stunt Virus Strains from Japan.

We present the complete genomic RNA sequences of seven isolates of Peanut stunt virus discovered in diseased legume plants in various regions in Japan. These sequences and the published viral sequences were compared with respect to nucleotide percentages. Their phylogenetic analysis showed that all the isolates belong to subgroup IA.

Complete Genome Sequences of Three Tomato Aspermy Virus Isolates in Japan.

We report here the first complete nucleotide sequences of genomic RNAs of three Tomato aspermy virus (TAV) isolates in Japan. Analysis of these sequences showed that they have unique characteristics in RNAs 2 and 3. The Japanese isolates are similar to each other compared to other TAVs.

Maximum permissible load for Kiso horses trotting over a short, straight course.

This study aimed to determine the load-bearing capacity of trotting Kiso horses using gait analysis. Ten Kiso horses with a height at withers of 128 cm were included. Their riders were fitted with a marker (70 mm in diameter placed on their chest) recorded by two digital DVD cameras while trotting along a short, straight course. In total, eight tests were performed for each horse: the first with a 70 kg load; six with randomly loaded weights ranging 80-130 kg; and then a final test again with a 70 kg load. Three-dimensional movement of the marker was analyzed using a motion capture system. The time series of vertical displacement of the marker underwent spectrum analysis by the maximum entropy method, and the autocorrelation coefficient was calculated. The first two peaks of the autocorrelation were defined as symmetry and regularity, and their sum was defined as stability. Regularity in the 120 kg test (0.54) was lower than that in the first 70 kg test (0.61), and stability in the 120 kg test (1.31) was lower than that in the first 70 kg test (1.42). We concluded that the maximum permissible load for a trotting Kiso horse is < 120 kg, which represents 31% of its bodyweight.

Comparison of the social systems of primates and feral horses: data from a newly established horse research site on Serra D'Arga, northern Portugal.

Horses are phylogenetically distant from primates, but considerable behavioral links exist between the two. The sociality of horses, characterized by group stability, is similar to that of primates, but different from that of many other ungulates. Although horses and primates are good models for exploring the evolution of societies in human and non-human animals, fewer studies have been conducted on the social system of horses than primates. Here, we investigated the social system of feral horses, particularly the determinant factors of single-male/multi-male group dichotomy, in light of hypotheses derived from studies of primate societies. Socioecological data from 26 groups comprising 208 feral horses on Serra D'Arga, northern Portugal suggest that these primate-based hypotheses cannot adequately explain the social system of horses. In view of the sympatric existence of multi- and single-male groups, and the frequent intergroup transfers and promiscuous mating of females with males of different groups, male-female relationships of horses appear to differ from those of polygynous primates.

Functional reassignment of Cellvibrio vulgaris EpiA to cellobiose 2-epimerase and an evaluation of the biochemical functions of the 4-O-ß-D-mannosyl-D-glucose phosphorylase-like protein, UnkA.

The aerobic soil bacterium Cellvibrio vulgaris has a ß-mannan-degradation gene cluster, including unkA, epiA, man5A, and aga27A. Among these genes, epiA has been assigned to encode an epimerase for converting D-mannose to D-glucose, even though the amino acid sequence of EpiA is similar to that of cellobiose 2-epimerases (CEs). UnkA, whose function currently remains unknown, shows a high sequence identity to 4-O-ß-D-mannosyl-D-glucose phosphorylase. In this study, we have investigated CE activity of EpiA and the general characteristics of UnkA using recombinant proteins from Escherichia coli. Recombinant EpiA catalyzed the epimerization of the 2-OH group of sugar residue at the reducing end of cellobiose, lactose, and ß-(1→4)-mannobiose in a similar manner to other CEs. Furthermore, the reaction efficiency of EpiA for ß-(1→4)-mannobiose was 5.5 × 10(4)-fold higher than it was for D-mannose. Recombinant UnkA phosphorolyzed ß-D-mannosyl-(1→4)-D-glucose and specifically utilized D-glucose as an acceptor in the reverse reaction, which indicated that UnkA is a typical 4-O-ß-D-mannosyl-D-glucose phosphorylase.

Crystal structure of Ruminococcus albus cellobiose 2-epimerase: structural insights into epimerization of unmodified sugar.

Enzymatic epimerization is an important modification for carbohydrates to acquire diverse functions attributable to their stereoisomers. Cellobiose 2-epimerase (CE) catalyzes interconversion between d-glucose and d-mannose residues at the reducing end of ß-1,4-linked oligosaccharides. Here, we solved the structure of Ruminococcus albus CE (RaCE). The structure of RaCE showed strong similarity to those of N-acetyl-D-glucosamine 2-epimerase and aldose-ketose isomerase YihS with a high degree of conservation of residues around the catalytic center, although sequence identity between them is low. Based on structural comparison, we found that His184 is required for RaCE activity as the third histidine added to two essential histidines in other sugar epimerases/isomerases. This finding was confirmed by mutagenesis, suggesting a new catalytic mechanism for CE involving three histidines.