Digestive enzyme activities of pancreas and intestinal digesta in streptozotocin-induced diabetic piglets

Six (Landrace × Large White) × Duroc crossbred, castrated weanling piglets were used to evaluate the effect of a streptozotocin (STZ) injection to induce diabetes on the activities of digestive enzymes derived from the pancreas (lipase, amylase, trypsin and chymotrypsin) in the pancreas and intestinal digesta. Fasting plasma glucose after the administration of STZ was maintained at the level of 302–491 mg/dL during this experiment, compared with the level of 89–125 mg/dL in the control group, and they were defined as the STZ‐induced diabetic piglets for about 7 weeks. Although their bodyweight increased in proportion to a quadratic curve (P < 0.0001) during 49 days after the administration of STZ, the growth of the STZ‐induced diabetic piglets was slower compared with the control. The STZ‐injection did not affect the percentage of the pancreas in bodyweight. The administration of STZ in the piglets tended to accelerate the activity of lipase (P = 0.06) and depress the activity of amylase (P = 0.15) or chymotrypsin (P = 0.18), as units/kg bodyweight, in the pancreas. In the case of measurement as units/kg bodyweight, the activities of intestinal digesta in the STZ group showed a tendency to be higher than those in control group, irrespective of the sort of enzymes. In conclusion, STZ‐induced diabetic piglets have a moderate digestive ability and the administration of exogenous digestive enzymes is not necessary when they are used as a diabetic animal model.     

Acinic cell carcinoma in an African pygmy hedgehog (Atelerix albiventris)

Abstract: A male African pygmy hedgehog ( Atelerix albiventris ), estimated to be 3 years old, presented with exophthalmos and fixed abduction of the right eye. Radiographic examination revealed a retrobulbar tumor in the right orbital cavity. The mass was surgically resected but recurred 3 months later and the hedgehog died. There was no gross or microscopic evidence of salivary or lacrimal gland involvement of the tumor at surgery or at necropsy. The histopathologic, immunohistochemical, and ultrastructural findings were those of acinic cell carcinoma, the origin of which was unknown. This is the first known case of acinic cell carcinoma in an African hedgehog.     

Cytochrome oxidase I gene sequence of Hypoderma sinense infecting yaks in the Qinghai-Tibet high plateau of China

The previous scanning electron microscopy study of the Hypoderma species suggested that Hypoderma sinense Pleske (H. sinense) was different from Hypoderma bovis (H. bovis) and Hypoderma lineatum (H. lineatum). In this study, the mitochondrial cytochrome oxidase I (COI) gene sequence of H. sinense was compared with those of the other two species. The H. sinense sequence showed only 88.3% homology to H. bovis and 88.5% to H. lineatum. The results of the sequencing analysis confirm that H. sinense is a different species from H. bovis and H. lineatum.     

Genetic and serological characterization of novel serotype G8 bovine group A rotavirus strains isolated in Japan

G8 bovine group A rotaviruses isolated in Japan were genetically and serologically characterized. The VP7 gene nucleotide and amino acid sequences revealed high identity with each other. All Japanese G8 strains were classified into the same lineage in the phylogenetic analysis based on VP7 gene sequences. Antisera to four Japanese G8 strains neutralized other G8 strains, but their neutralizing titers were between 8-fold lower and 2-fold higher than homologous strains. These results suggest that the VP7s of Japanese G8 strains have similar genetic and serologic characteristics. Observed differences in the neutralizing abilities of antisera for each strain appear to depend on differences in the P serotypes/genotypes.     

Assessment of bovine X- and Y-bearing spermatozoa in fractions by discontinuous percoll gradients with rapid fluorescence in situ hybridization

This study was designed to apply the method of discontinuous Percoll gradients for sex preselection in bovine semen by using a current developed molecular technique, fluorescence in situ hybridization (FISH). In addition, we attempted to amplify the level of enrichment of X- or Y-bearing spermatozoa by treating for activating sperm motility performance with 10 mM caffeine. Bovine spermatozoa were fractionated on Percoll gradients into two major subpopulations of motile spermatozoa (bottom fraction) and weak motile spermatozoa (top fraction). The percentage of Y-bearing spermatozoa in the top fraction (52.9%) slightly exceeded and that in the bottom fraction (44.3%) decreased significantly (P<0.001) compared with the theoretical ratio (50:50). Washing sperm with BO medium affected a deviation between the two sex populations, whereas semen activated with caffeine showed no difference in the percentage of X- and Y-bearing spermatozoa in both fractions compared with the theoretical ratio (50:50). These results show that the proportion of X- and Y-bearing bovine spermatozoa can deviate after discontinuous Percoll gradients, although the proportion of X- and Y-bearing bovine spermatozoa was affected by sperm motility of the sample applied.     

Immunocytochemical evaluation of epithelial–mesenchymal transition in epithelial tumors of dogs and cats

Epithelial–mesenchymal transition (EMT) plays a crucial role in metastasis of epithelial tumors; however, it is challenging to detect EMT by cytology. In the present study, EMT was visualized by fluorescence-immunocytochemistry (FICC). Air-dried smears from epithelial tumors of dogs (n=22) and cats (n=9) were stained using mouse monoclonal anti-E-cadherin and rabbit monoclonal anti‐vimentin antibodies. Enzymatic immunohistochemistry (IHC) revealed that 51.6% (8/22 in dogs, 8/9 in cats) of the cases showed EMT. In dogs, FICC could detect EMT in 62.5% (5/8) of those cases. In cats, FICC could detect EMT in 100% (8/8) of the cases. In conclusion, the present FICC method could successfully detect EMT using conventional air-dried cytology smear slides.     

Hormone level analysis on adventitious root formation in Eucalyptus globulus

Eucalyptus globulus is the one of the most economically important trees for pulp and paper industries due to its fast growth and short harvesting cycle. However, E. globulus is well known as a woody plant that is hard to propagate vegetatively. In this study, we found wide distribution of rooting ability among seven independent genotypes we tested. Analysis of the mechanism of adventitious rooting by using the auxin transport inhibitor, N-naphthylphthalamic acid, revealed that polar auxin transport is crucial in root formation. The gravitropism of the stem was highly correlated to the percentage of adventitious root formation. Hormonal analysis showed that the levels of indole-3-acetic acid (IAA) were the same between difficult-to-root and easy-to-root genotypes, whereas levels of IAAsp (indole-3-acetyl aspartic acid) were higher in the difficult-to-root genotype, indicating that IAA metabolism might play an important role in adventitious root formation in this species. Levels of several cytokinins exhibited differences between genotypes that varied in their cutting performance and rooting ability. Furthermore, higher level of cytokinin in elongating shoots were correlated with rooting percentage. Taken together, our results indicate that both auxins and cytokinins play a role in adventitious root formation in E. globulus, and that a complex interplay between the levels of auxins and cytokinins and their metabolism might result in root formation in this commercially important plant.     

Negative feedback regulation ensures the one receptor-one olfactory neuron rule in mouse

In the mouse olfactory system, each olfactory sensory neuron (OSN) expresses only one odorant receptor (OR) gene in a monoallelic and mutually exclusive manner. Such expression forms the genetic basis for OR-instructed axonal projection of OSNs to the olfactory bulb of the brain during development. Here, we identify an upstream cis-acting DNA region that activates the OR gene cluster in mouse and allows the expression of only one OR gene within the cluster. Deletion of the coding region of the expressed OR gene or a naturally occurring frame-shift mutation allows a second OR gene to be expressed. We propose that stochastic activation of only one OR gene within the cluster and negative feedback regulation by that OR gene product are necessary to ensure the one receptor-one neuron rule.     

Mechanism of self-sterility in a hermaphroditic chordate

Hermaphroditic organisms avoid inbreeding by a system of self-incompatibility (SI). A primitive chordate (ascidian) Ciona intestinalis is an example of such an organism, but the molecular mechanism underlying its SI system is not known. Here, we show that the SI system is governed by two gene loci that act cooperatively. Each locus contains a tightly linked pair of polycystin 1-related receptor (s-Themis) and fibrinogen-like ligand (v-Themis) genes, the latter of which is located in the first intron of s-Themis but transcribed in the opposite direction. These genes may encode male- and female-side self-recognition molecules. The SI system of C. intestinalis has a similar framework to that of flowering plants but utilizing different molecules.     

Critical roles of activation-induced cytidine deaminase in the homeostasis of gut flora

Activation-induced cytidine deaminase (AID) plays an essential role in class switch recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin genes. We report here that deficiency in AID results in the development of hyperplasia of isolated lymphoid follicles (ILFs) associated with a 100-fold expansion of anaerobic flora in the small intestine. Reduction of bacterial flora by antibiotic treatment of AID-/- mice abolished ILF hyperplasia as well as the germinal center enlargement seen in secondary lymphoid tissues. Because an inability to switch to immunoglobulin A on its own does not lead to a similar phenotype, these results suggest that SHM of ILF B cells plays a critical role in regulating intestinal microflora.