Toshi Watanabe

Microsatellite variability reveals the necessity for genetic input from wild giant pandas (Ailuropoda melanoleuca) into the captive population

Recent success in breeding giant pandas in captivity has encouraged panda conservationists to believe that the ex situ population is ready to serve as a source for supporting the wild population. In this study, we used 11 microsatellite DNA markers to assess the amount and distribution of genetic variability present in the two largest captive populations (Chengdu Research Base of Giant Panda Breeding, Sichuan Province and the China Research and Conservation Center for the Giant Panda at Wolong, Sichuan Province). The data were compared with those samples from wild pandas living in two key giant panda nature reserves (Baoxing Nature Reserve and Wanglang Nature Reserve). The results show that the captive populations have retained lower levels of allelic diversity and heterozygosity compared to isolated wild populations. However, low inbreeding coefficients indicate that captive populations are under careful genetic management. Excessive heterozygosity suggests that the two captive populations have experienced a genetic bottleneck, presumably caused by founder effects. Moreover, evidence of increased genetic divergence demonstrates restricted breeding options within facilities. Based on these results, we conclude that the genetic diversity in the captive populations is not optimal. Introduction of genetic materials from wild pandas and improved exchange of genetic materials among institutions will be necessary for the captive pandas to be representative of the wild populations.

Microreview: Capsule-associated genes of Cryptococcus neoformans

Cryptococcosis, caused by Cryptococcus neoformans is a common systemic mycosis in man and animals, particularly immunocompromised patients. This pathogenic fungus produces a thick extracellular polysaccharide capsule. Four capsule-associated genes (CAP10, CAP59, CAP60, CAP64) were cloned and sequenced, and proved to be essential for capsule synthesis. However biochemical functions of CAP gene products have not been clarified yet. Recently, the relatedness of the polysaccharide capsule and four capsule-associated genes has partly been elucidated. Nucleotide sequence of four CAP gene fragments was analyzed for phylogenetic relationships, and they were in agreement with the conventional classification of varieties and serotypes within C. neoformans. Expression of four CAP genes and capsule size were examined using two media containing different amount of glucose, and the results indicated that CAP genes might play important roles in elaboration of extracellular polysaccharide capsule. Furthermore, analyses of CAP genes in various clinical samples would give the useful information to diagnose cryptococcosis in human and animals.

Excretion of bisphenol A into rat milk

Bisphenol A (BPA), an endocrine-disrupting chemical, is widely used in the production of polycarbonate plastic and epoxy resins. This study analyzed the BPA concentration in rat milk, in order to assess the risk of BPA transfer to the offspring via milk. The rats ingested BPA by oral administration or by drinking the water in a polycarbonate bottle, and the milk samples were collected using an automated experimental milker. The BPA concentration in the samples of milk, drinking water, and food was analyzed by LC/MS. In the case of milk samples obtained from rats injected with BPA at 2, 4, 8, and 24 h prior to milking, the BPA concentrations were 0.462 ± 0.182 ppm, 0.138 ± 0.0185 ppm, 0.080 ± 0.0197 ppm, and 0.0232 ± 0.0051 ppm, respectively. Also, in the cases of the water sample left in polycarbonate bottle and the milk sample obtained from rats provided it as drinking water, the concentrations of BPA were 0.000332 ± 0.00015 ppm and 0.0184 ± 0.0050 ppm, respectively. The results indicate that the BPA administered to the dams was transferred to their milk, and that BPA concentration in milk was higher at the early period after the single bolus dose. Additionally, these results reveal that sequential elution of BPA from polycarbonate containers in a much diluted form would undergo bioaccumulation in dams and likely be transferred to pups via milk in a much concentrated form.

Identification and characterization of ten polymorphic microsatellite loci in the red panda Ailurus fulgens

Ten polymorphic microsatellite loci were characterized from two genomic DNA-enriched libraries of the red panda (Ailurus fulgens). The number of observed alleles among 35 samples of red pandas ranged from five to 12. Observed and expected heterozygosities were 0.286–0.971 and 0.443–0.894, and the mean polymorphic information content was 0.712. All loci followed Hardy–Weinberg expectations except Aifu-14 and Aifu-16, which may due to the presence of inbreeding or null alleles. Three pairs of loci exhibited significant linkage disequilibrium after Bonferroni correction for multiple comparisons. These microsatellites would be useful to strengthen population management, genetic diversity exploration, and demographic history speculation of this species.

Analysis of the breast milk of giant pandas (Ailuropoda melanoleuca) and the preparation of substitutes.

The first milk substitute for giant panda cubs was developed in 1988 based on limited data about giant panda breast milk and that of certain types of bear. Mixtures of other formulas have also been fed to cubs at some facilities. However, they are not of sufficient nutritional quality for promoting growth in panda cubs. Here, we report analysis of giant panda breast milk and propose new milk substitutes for cubs, which were developed based on the results of our analysis. The Chengdu Research Base of Giant Panda Breeding obtained breast milk samples from three giant pandas. Up to 30 ml of breast milk were collected from each mother by hand. Then, the milk samples were frozen and sent to Nihon University. The levels of protein, fat, carbohydrates, ash, moisture, vitamins, minerals, total amino acids, fatty acids, lactose and other carbohydrates in the milk were analyzed. The breast milk samples exhibited the following nutritional values: protein: 6.6–8.5%, fat: 6.9–16.4%, carbohydrates: 2.5–9.1%, ash: 0.9–1.0% and moisture: 67–83%. We designed two kinds of milk substitutes based on the data obtained and the nutritional requirements of dogs, cats and rodents. The nutritional composition of the milk substitutes for the first and second stages was as follows: protein: 38 and 26%, fat: 40 and 40%, carbohydrates: 13 and 25%, ash: 6 and 6% and moisture: 3 and 3%, respectively. In addition, the substitutes contained vitamins, minerals, taurine, docosahexaenoic acid, lactoferrin, nucleotides and other nutrients.