Tyrosinase (Tyr) Gene Mutation in Albino Mongolian Gerbil (Meriones unguiculatus)

Tyrosinase is encoded by the Tyr (c or albino) locus and is the key enzyme in pigment biosynthesis. Loss of function of this enzyme caused by gene mutation results in albinism. Most cases of albinism are caused by missense mutations of tyrosinase. Albino mutations in Tyr have been identified in various animals, including human, mouse, rat, rabbit, cattle, cat, and ferret, but not in gerbil. We created two new gerbil strains: MON/Num/a (inbred agouti phenotype) and MON/Num/c (albino phenotype). Here, we report that four nucleotide substitutions in the Tyr gene caused two missense mutations in amino acids in the albino gerbil: a G-to-A mutation at position 204 in exon 1 caused R77H, and A-to-G at position 1392 and G-to-T at position 1393 in exon 5 caused Q473R. The substitution at position 1408 in exon 5 was silent. These missense mutations are conserved in all albino phenotypes we tested. Therefore, we suggest that these mutations are responsible for albinism in gerbil.

<i>In Vitro</i>Culture of Shell Gland Epithelial Cells in Japanese Quail (<i>Coturnix coturnix japonica</i>)

To investigate the secretion of protoporphyrin IX (PpIX), superficial eggshell pigment, from shell gland cells of Japanese quail, the epithelial cells of the gland were collected and isolated for cultivation in vitro. An analysis of a peak for PpIX in the cells was performed using a fluorescence microplate reader. The measurement showed that PpIX has a peak of excitation wavelength at 410 nm and emission wavelength at 606 nm in the culture medium (HamF12 + 4% HCl). Volumes of PpIX in the medium after 4 hour culture of the cells were measured with a microplate reader using filter set of excitation wavelength 400/30nm and emission wavelength 620/40nm. However the cells did not secrete significantly PpIX during 4 hour incubation in this culture system, addition of quail plasma to the medium resulted in significantly higher secretion. A cultivation system in this study is able to use for the study on the mechanism of the secretion of eggshell pigment, PpIX from Japanese quail shell gland epithelial cells.

Calcium Participates in Secretion of Porphyrin from Shell Gland Epithelial Cells of Japanese Quail (<i>Coturnix coturnix japonica</i>)

To investigate factors involved in the secretion of protoporphyrin IX (PpIX), a superficial eggshell pigment, from shell gland epithelial cells of Japanese quail, we cultured cells in Ham’s F12 medium with calcium chloride and quail plasma. The addition of hormones (prostaglandin F2α, progesterone, estradiol-17β) to the medium did not change the PpIX concentration in the culture supernatant, but changing the calcium chloride (CaCl2) concentration did: a lower concentration of CaCl2 led to a higher PpIX concentration;0 mM CaCl2 enhanced the secretion of PpIX from epithelial cells prepared at 5 or 7 mM CaCl2. The result suggests that a drop in concentration of CaCl2 mimics the end of shell calcification and stimulates rapid secretion of PpIX in vivo. Bovine serum albumin was almost as effective as quail plasma for PpIX secretion in culture, and would facilitate further study of the mechanism of PpIX secretion.

Evaluation of Physiological Responses to Human Approach Manner in Pet Dogs

We used eye-surface temperature and heart rate as simple, noninvasive physiological indices to evaluate dogs’ responses to an approaching person. Thirteen healthy pet dogs (49.62 ± 31.42 months;19.28 ± 11.46 kg) were recruited as subjects to investigate physiological responses to approach. We set up two types of approach (smiling and expressionless) by familiar or unfamiliar people of either sex, and all tests were recorded by video cameras. Eye temperature was measured with an infrared thermal camera image, and the dog was equipped with a heart-rate monitor during testing. There were temporal changes in heart rate, and response time differed between HR and eye temperature. Although it may be the one which has to control both a background of the dogs or observational environment, and the response time of each parameter needs to be considered, these two parameters should be useful for non-invasive monitoring of physiological states in dogs in various practical animal situations.

A genetic typing method for albino mutation in the Mongolian gerbil by PCR-RFLP analysis

INTRODUCTION The Mongolian gerbil(Meriones unguiculatus)has been used as an animal model for pharmacology(Wu et al.2008),parasitology(Lim et al.2004),and studies of reproduction(Kai et al.1995).The molecular mechanisms of several coat-color phenotypes are known in gerbils(Petrij et al.2001,2007).On the other hand,although albinism in gerbils was first reported by Matsuzaki et al.(1989),its molecular mechanism is still unclear.In a previous study,we reported the establishment of the albino gerbil strain(strain code:MON/Num/c)as a closed colony and the agouti-colored strain(strain code:MON/Num/a)as inbred.Our albino strain had 4 nucleotide substitutions and 2 missense mutations(R77H in exon 1 and Q473R in exon 5)in the tyrosinase(Tyr)gene(Ukaji et al.2016).