Patterns of C-heterochromatin and telomeric DNA in two representative groups of small apes,the genera <Emphasis Type="Italic">Hylobates</Emphasis> and <Emphasis Type="Italic">Symphalangus</Emphasis>

The course of chromosome evolution in small apes is still not clear, though painting analyses have opened the way for elucidating the puzzle. Even the C-banding pattern of the lar-group of gibbons (the genus Hylobates) is not clarified yet, although our previous studies suggested that lar-group gibbons have a unique C-banding pattern. We therefore made observations to establish C-banded karyotypes of the agile gibbons included in the lar-group. The data were compared with those of siamangs (the genus Symphalangus), which carry distinctive C-bands, to determine the chromosomal patterns in each group. C-banded chromosomes of agile gibbons showed several terminal, interstitial and paracentric bands, whose patterns are specific for each chromosome, whereas the C-bands of siamangs were located only at the terminal and centromeric regions in most chromosomes. Moreover, the C-bands of agile gibbons and siamangs were shown to be G+C-rich and A+T-rich DNA, respectively, by DAPI/C-band sequential staining. Additionally, PRINS labelling with a telomere primer revealed that agile gibbons have telomeric DNA only at chromosome ends where there is no C-band (non-telomeric heterochromatin), whereas the telomeric DNA of siamangs is located in the terminal C-banded regions (telomeric heterochromatin). Although the evolutionary mechanisms in small apes are still unknown, C-banding patterns and distribution of telomeric DNA sequences should provide valuable data to deduce the evolutionary pathways of small apes.     

SEM study on the dorsal lingual surface of the large flying fox,Pteropus vampyrus

The dorsal lingual surface of the large flying foxes were examined by scanning electron microscopy. Filiform, fungiform and vallate papillae were observed. The filiform papillae were distributed over the entire dorsal surface of the tongue. The filiform papillae notably differed in morphology by their location on the tongue and could be classified into 6 types: 1) scale-like, 2) giant trifid, 3) small crown-like, 4) large crown-like, 5) long conical and 6) short conical papillae. The fungiform papillae were present rounded bodies on the anterior 2/3 of the tongue. The large flying foxes showed the triangular arrangement of the three vallate papillae, with the apex of the triangle directed posteriorly. These findings indicate that the tongue of the large flying bat is similar to that of the lesser dog-faced fruit bat.     

Differences in rectal temperatures measured at depths of 4–19 cm from the anal sphincter during exercise and rest

The purpose of the present study was to examine the discrepancies in rectal temperature (T _re) at various depths. Nineteen young males performed two bouts of bicycle exercise and recovery. T _re was simultaneously measured at depth of 4, 6, 8, 10, 13, 16, and 19 cm, alongside the measurement of skin temperatures. We found small but statistically significant differences by depth in the absolute T _re, the magnitude of rise in T _re and the lag of response in T _re. During the stabilization stage before exercise, T _re at 4 cm-depth was 0.5°C lower than T _re at 16 cm-depth (p < 0.05). As the depth measured in the rectum was shallower, the rise in T _re during exercise was greater. However the rise in T _re at 10, 13, 16 and 19 cm showed no systemic difference. Among seven depths, T _re at 16 cm-depth had the most stable feature with the longest latent period (3.1 ± 1.3 min) and the smallest rise (0.8 ± 0.3°C), while T _re at 4 cm-depth was the most responsive to the change of exercise and rest with the shortest latent period (1.0 ± 0.6 min) and the greatest rise (1.2 ± 0.5°C). The differences observed in the depths from 4 to 19 cm were offset by exercise to some extent. In summary, T _re appeared in different manners according to the seven depths during the repetition of exercise and rest, but T _re deeper than 10 cm-depth seemed to have no systematic differences.     

Strain-related differences in bioactivation of vinyl carbamate and formation of DNA adducts in lungs of A/J, CD-1, and C57BL/6 mice.

Inbred strains of mice exhibit differing susceptibilities to formation of lung tumors induced by procarcinogens including ethyl carbamate (EC) and vinyl carbamate (VC). Strain A/J mice are susceptible, whereas C57BL/6 mice are resistant to lung tumor development. In this study, we tested the hypothesis that differential susceptibilities of A/J, CD-1, and C57BL/6 mice to lung tumor development are associated, in part, with their capacities for VC bioactivation and with the extents of DNA adduct formation. Previous studies have shown that the P450 isozyme CYP2E1 and microsomal carboxylesterases are involved in activation and detoxication of VC, respectively. Bioactivation capacity, as estimated by ratios of p-nitrophenol hydroxylase, a CYP2E1 catalytic marker, to carboxylesterase activities, was greater in control A/J (1.32 +/- 0.18 x 10(-6)) and CD-1 (1.25 +/- 0.29 x 10(-6)) mice than in control C57BL/6 (0.69 +/- 0.12 x 10(-6)) mice. The ratios were reduced in all three strains of mice treated with VC. Covalent binding of [(14)C-carbonyl]-VC to lung proteins was time- and dose-dependent, and was significantly higher in A/J and CD-1 mice than in C57BL/6 mice. Experiments using (32)P-postlabeling/thin-layer chromatography showed formation of the DNA adducts 1,N:(6)-ethenodeoxyadenosine and 3,N:(4)-ethenodeoxycytidine in lungs of mice treated with VC. The DNA adducts were detected at 30 min after treatment, peaked at 60 min, and declined thereafter. Levels of 1,N:(6)-ethenodeoxyadenosine and 3,N:(4)-ethenodeoxycytidine were about 70% higher in A/J and CD-1 mice than in C57BL/6 mice. These results indicated that formation of VC metabolites in these murine strains is linked to their bioactivation capacities, and suggested that this attribute may confer differing susceptibilities to lung tumor development.     

A whole-arm translocation (WAT8/9) separating Sumatran and Bornean agile gibbons,and its evolutionary features

Gibbons, like orangutans, are a group of threatened Asian apes, so that genetic monitoring of each species or subspecies is a pressing need for conservation programmes. We conducted a project to take, as far as possible, samples of known origin from wild-born animals from Sumatra and Borneo (Central Kalimantan) for genetic monitoring of agile gibbons. As a result, we found a whole arm translocation between chromosomes 8 and 9 (WAT8/9) specific to Sumatran agile gibbons. Furthermore, population surveys suggested that the form with the WAT8/9 seems to be incompatible with an ancestral form, suggesting that the former might have extinguished the latter from Sumatran populations by competition. In any case, this translocation is a useful chromosomal marker for identifying Sumatran agile gibbons. Population genetic analyses with DNA showed that the molecular genetic distance between Sumatran and Bornean agile gibbons is the smallest, although the chromosomal difference is the largest. Thus, it is postulated that WAT8/9 occurred and fixed in a small population of Sumatra after migration and geographical isolation at the last glacial period, and afterwards dispersed rapidly to other populations in Sumatra as a result of the bottleneck effect and a chromosomal isolating mechanism.     

Ethnic differences in thermoregulatory responses during resting,passive and active heating: application of Werner’s adaptation model

For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28°C with 50% RH), (2) a passive heating condition (28°C with 50% RH; leg immersion in a hot tub at a water temperature of 42°C), and (3) an active heating condition (32°C with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives. It is suggested that tropical natives’ homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation. The enhanced stability of internal body temperature and the extended thermoregulatory capability of vascular circulation in the extremities of tropical natives can be interpreted as an interactive change to accomplish a thermal dynamic equilibrium in hot environments. These heat adaptive traits were explained by Wilder’s law of initial value and Werner’s process and controller adaptation model.     

Patterns of C-heterochromatin and telomeric DNA in two representative groups of small apes, the genera Hylobates and Symphalangus.

The course of chromosome evolution in small apes is still not clear, though painting analyses have opened the way for elucidating the puzzle. Even the C-banding pattern of the lar-group of gibbons (the genus Hylobates) is not clarified yet, although our previous studies suggested that lar-group gibbons have a unique C-banding pattern. We therefore made observations to establish C-banded karyotypes of the agile gibbons included in the lar-group. The data were compared with those of siamangs (the genus Symphalangus), which carry distinctive C-bands, to determine the chromosomal patterns in each group. C-banded chromosomes of agile gibbons showed several terminal, interstitial and paracentric bands, whose patterns are specific for each chromosome, whereas the C-bands of siamangs were located only at the terminal and centromeric regions in most chromosomes. Moreover, the C-bands of agile gibbons and siamangs were shown to be G+C-rich and A+T-rich DNA, respectively, by DAPI/C-band sequential staining. Additionally, PRINS labelling with a telomere primer revealed that agile gibbons have telomeric DNA only at chromosome ends where there is no C-band (non-telomeric heterochromatin), whereas the telomeric DNA of siamangs is located in the terminal C-banded regions (telomeric heterochromatin). Although the evolutionary mechanisms in small apes are still unknown, C-banding patterns and distribution of telomeric DNA sequences should provide valuable data to deduce the evolutionary pathways of small apes.     

The effects of black garlic on the working memory and pyramidal cell number of medial prefrontal cortex of rats exposed to monosodium glutamate

Monosodium glutamate-induced exitotoxicity causes oxidative stress in many brain areas, including the medial prefrontal cortex. The ethanolic garlic (Allium sativum) extract is considered as a neuroprotective substance. The present study aimed at investigating the effects of the ethanolic fermented garlic extract on the working memory and the pyramidal cell number of the medial prefrontal cortex of adolescent male Wistar rats exposed to monosodium glutamate (MSG). Twenty-five rats were randomly divided into five groups. The C– group was given 0.9% NaCl solution. The C?+?group was given 2?mg/g bw of MSG. The T1, T2, and T3 groups were given MSG and garlic extract (0.0125, 0.025, and 0.05?mg/g bw, respectively). All treatments were conducted for 10?days. The working memory capability of the rats was measured using Y-maze test. The total number of pyramidal cells of the medial prefrontal cortex was estimated using physical fractionator method. The working memory performances of the T1, T2, and T3 groups were significantly better than that of the C?+?group. There were no significant differences between groups in the estimated total number of pyramidal cell of medial prefrontal cortex. The MSG may not cause the death of neurons, but it may modify neuronal architectures that are sufficient to disrupt memory functions. Black garlic may play a role as an antioxidant agent that prevents the prefrontal cortex from glutamate-induced oxidative stress. It is concluded that the ethanolic fermented garlic extract prevented the working memory impairment following MSG administration.