Spontaneous Glomerular and Tubulointerstitial Lesions in Common Marmosets (Callithrix jacchus)

Spontaneous progressive nephropathy dominated by glomerular lesions in common marmosets has been reported. However, the histopathologic characteristics, including the relationship between glomerular and tubulointerstitial lesions, have not been described in detail. In the present study, the authors examined the histopathologic characteristics of the background renal lesions in common marmosets (3 males and 9 females, 3 to 8 years old). The severity of glomerular lesions was graded into 3 classes: grade I, no alteration; grade II, hilar/focal increase of mesangial matrix; grade III, global/diffuse increase of mesangial matrix. Tubulointerstitial lesions (tubular regeneration and hyperplasia and interstitial inflammation and fibrosis) were scored according to the area of each lesion. The renal lesions were characterized by enlargement of glomeruli, expanded mesangial area with increase of periodic acid-Schiff reaction-positive matrix, tubular regeneration and hyperplasia, and interstitial inflammation and fibrosis. Glomerular lesions progressed with increasing mesangial matrix and aging. Additionally, the tubulointerstitial lesions became exacerbated with progressing glomerular lesions. Tubular hyperplasia was divided into 4 types according to the structure of the cell layer (simple or stratified-like), the area of increased lining cells (partial or entire), cytoplasmic staining (eosinophilic or basophilic), brush border and thickness of basement membrane, and the activity of cell proliferation. In conclusion, the background renal lesions in common marmosets were characterized by glomerular lesions with increase of mesangial matrix, which progressed with aging, and secondary tubulointerstitial lesions, including tubular hyperplasia. Those lesions were thus diagnosed as progressive glomerulonephropathy in common marmosets.     

Genetic organization and preferential distribution of putative pilus gene clusters in Streptococcus suis

Recent analyses of Streptococcus suis isolates using multilocus sequence typing (MLST) suggested the importance of sequence type (ST) 1 and ST27 complexes for animal hygiene and public health. In this study, to investigate whether pilus-associated genes in S. suis can be used as novel genetic markers for important clonal groups, we examined the correlation between STs and putative pilus-associated gene profiles in S. suis. Genomic searches using sequenced genomes and sequence data determined in several isolates revealed the presence of at least four distinct putative pilus gene clusters in S. suis (srtBCD, srtE, srtF, and srtG clusters). On the basis of the presence or absence of genes in the four clusters, 108 S. suis isolates from various origins were classified into 12 genotypes (genotypes A–L). Genotypes A and B, which possessed srtBCD plus srtF clusters and srtF plus srtG clusters, respectively, were the most common in isolates from diseased pigs and humans, and 29.9% and 59.8% of the isolates belonged to genotypes A and B, respectively. In contrast, only 4.8% and 28.6% of isolates from healthy carriers were genotypes A and B, respectively. MLST analysis showed the associations of genotypes A and B with ST1 and ST27 complexes, respectively. In addition, srtBCD and srtG clusters were preferentially distributed to ST1 and ST27 complex members, respectively. These results suggest that profiling of selected pilus-associated genes could be used as an easy screening method to monitor isolates important for S. suis infection.     

Segmentation of the Pathophysiological Stages of Diabetic Changes in the db/db Mouse

The db/db mouse is one of the diabetes mellitus animal models and if the pathophysiological stages of diabetic changes in the mouse model could simulate the stages in human diabetes, the db/db mouse could be used to better evaluate drug candidates. Blood insulin, HbA1c levels and morphological features of pancreatic islets in db/db mice were evaluated to determine the pathophysiological stage. At 6 weeks of age, db/db mice showed the highest level of plasma insulin and lowest level of HbA1c, and histopathological examination revealed enlarged islets with a circular shape and hypertrophic islet cells. By 9 and 12 weeks of age, the plasma insulin levels had decreased to mid levels and HbA1c had increased to mid to high levels; histopathological examination at this time revealed two types of islets coexisting, enlarged circular islets and small irregular-shaped islets. By 15 and 22 weeks of age, plasma insulin had decreased further to low levels and HbA1c was at its highest level; the histopathological examination at this time revealed an increase in irregular-shaped and small islets. Based on blood insulin levels, HbA1c levels and histopathology findings in the db/db mice in this study, the clinical staging of diabetic changes were recognized. The pathophysiological stages of diabetes mellitus in this animal model were similar to the stages in humans.     

PCR-based detection of blood parasites in cattle and adult Rhipicephalus appendiculatus ticks

To ascertain the infection rate for tick-borne pathogens in Zambia, an epidemiological survey of Theileria parva, Babesia bigemina and Anaplasma marginale in traditionally managed Sanga cattle was conducted using PCR. Of the 71 native Zambian cattle, 28 (39.4%) were positive for T. parva, 16 (22.5%) for B. bigemina and 34 (47.9%) for A. marginale. The mixed infection rate in cattle was 8.5% (6/71), 16.9% (12/71), 7.0% (5/71) and 2.8% (2/71) for T. parva/B. bigemina, T. parva/A. marginale, B. bigemina/A. marginale and T. parva/B. bigemina/A. marginale, respectively.To predict the risk for transmission of tick-borne pathogens from ticks to cattle, a total of 74 Rhipicephalus appendiculatus ticks were collected from a location where cattle had been found positive for T. parva. Of the ticks collected, 10 (13.5%) were found to be PCR-positive for T. parva. The results suggest that the infection rate for tick-borne pathogens was relatively high in Sanga cattle and that adult R. appendiculatus ticks were highly infected with T. parva.     

Effect of SCD and SREBP genotypes on fatty acid composition in adipose tissue of Japanese Black cattle herds

Fatty acid composition of beef adipose tissue is one of important traits because high proportions of monounsaturated fatty acid are related to favorable beef flavor and tenderness. In this study, we investigated effects of genetic factors such as stearoyl-CoA desaturase (SCD) and sterol regulatory element binding protein (SREBP) on beef carcass traits including fatty acid composition using two cattle populations. Sire effect was significantly related to almost all traits except BMS, suggesting that the trait examined in this study is highly controlled by genetic factors. The effect of SCD genotype on fatty acid composition was detected remarkably in both cattle groups, especially on stearic and oleic acids. This result was consistent with our previous studies and suggests that SCD is associated with fatty acid composition. Unlike SCD genotyping, the effect of SREBP genotype was not identified in this study. Our results suggested that SCD genotype would contribute to improving beef quality in field populations. Further studies about the relationship among these factors will bring an insight into the molecular mechanism of fatty acid metabolism in cattle.     

Technical note: viability and motility of vitrified/thawed primordial germ cell isolated from common carp (Cyprinus carpio) somite embryos

The feasibility of cryopreserving common carp (Cyprinus carpio) primordial germ cells (PGC) by vitrification of whole embryos at the 22- to 28-somite stage was investigated. Green fluorescent protein (GFP)-labeled PGC were cooled rapidly using liquid nitrogen after exposure to a pretreatment solution containing 1.5 M cryoprotectant (ethylene glycol or dimethyl sulfoxide, 30 or 50 min) and a vitrification solution containing 3 M cryoprotectant and 0.5 M sucrose (5, 10, 20, or 30 min). Embryonic cells that were pretreated for 30 min and vitrified for 20 min with ethylene glycol had the greatest rate of survival of embryonic cells (68.6%; P < 0.01), an optimal highest percentage of viable PGC (73.8 to 74.9%; P < 0.05), and no evidence of ice formation after thawing. The vitrified/thawed PGC were transplanted into blastula-stage embryos from goldfish (Carassius auratus). The PGC maintained their motility and moved to the gonadal ridge of the host embryo. Thus, the combination of vitrification and transplantation to produce germ-line chimeras is a powerful tool for the artificial production of next-generation offspring.     

Partitioning of photosynthates originating from bent shoots in the arching and high-rack culture systems of cut rose production

The arching and high-rack culture systems were developed and patented by Japanese rose growers. Both culture systems have bent canopies (lower bent shoots). In the arching culture system, shoots sprouting from the crown are harvested as cut flowers. However, the high-rack culture system also has a bent canopy originating from the mother stem (upper bent shoots) and flower stems sprout and is harvested at the top of each mother stem. Partitioning of photosynthates originating from bent shoots in arching and high-rack culture systems of rose production was investigated to elucidate how carbohydrates are re-allocated from the bent shoots in different culture systems of roses. At the flowering stage in both culture systems, 50–70% of ¹³C-photosynthates originated from bent shoots were exported to other parts within 72 h after ¹³CO₂ feeding to the bent shoot. In the arching culture system, photosynthates from lower bent shoots were partitioned mainly to the roots and crown. Similarly, in the high-rack culture system, between 71 and 86% of the exported carbon from the bent shoots were allocated to below the point of bending (roots + crown + mother stems) and only 9–28% was allocated to flowering shoots above the point of bending. In both culture systems, photosynthate translocation from the lower bent shoot directly to flowers was low. Accordingly, bent shoots in rose plants acted as a source of photosynthates, independent of culture system. The height of the bent shoots determined for a great deal in the re-allocation of the photosynthates, and provides a partial explanation for difference in production of cut roses.     

Genotyping of Giardia intestinalis from domestic and wild animals in Japan using glutamete dehydrogenase gene sequencing

To determine the genotypes of Giardia intestinalis from domestic and wild animals in Japan, Giardia isolates obtained from feces of 24 dogs kept in households and breeding kennels, three companion cats, five dairy calves and three wild monkeys, Macaca fuscata, were genotyped using the 177 bp sequence of the glutamete dehydrogenase gene (gdh). The genotypes were assemblages A, C, D or A/D for dog isolates, Assemblage F for cat isolates, assemblages A or E for calf isolates and assemblage B for monkey isolates. This is the first report on the genotypes of Giardia isolates from cats, calves and wild monkeys in Japan.     

Effects of exposure to a 50 Hz electric field on plasma levels of lactate, glucose, free Fatty acids, triglycerides and creatine phosphokinase activity in hind-limb ischemic rats

We previously reported that extremely low frequency electric fields (ELF-EFs) affect energy metabolism in stressed conditions. To further confirm this, the effect of exposure to ELF-EFs on the experimental ischemic rat was examined. The test was based on a comparison of rats treated with EF alone, ischemic surgery alone, the combination of EF with ischemic surgery, or no treatment (double sham). The EF condition used in this study was an alternating current of 50 Hz EF at 17 500 V/m intensity for 15 min per day. The exposure to EF in ischemic rats significantly decreased plasma levels of free fatty acids and triglycerides, compared to those of the no treatment or EF alone group. The plasma lactate levels of two ischemic groups peaked on experimental day-4 and gradually decreased until the end of the study. The changes in the lactate levels induced by ischemia did not show any difference between rats treated with ischemia alone or a combination of ischemia with an EF. Any changes in plasma levels of glucose and creatine phosphokinase activity were not influenced by EF treatment. These results indicate that the EF effect on glycolysis parameters, plasma lactate or glucose levels, does not appear in a highly stressed condition and that EF effects varied dependent on the condition of organism but ELF-EF used in this study have impact on lipid metabolism parameter in a hind-limb ischemic rat. However, further studies are needed to elucidate the association of ELF-EF with the lipid metabolism system.     

In vitro susceptibility and a new point mutation associated with tylosin-resistance in Japanese canine intestinal spirochetes

The in vitro susceptibilities of six commonly used antimicrobial agents against 29 isolates of intestinal spirochetes isolated from dogs in Japan were examined by the agar dilution technique. In addition, the genetic basis of tylosin resistance in in vitro selected resistant mutants of two reference strains and three tylosin-susceptible field isolates obtained by three successive subcultures on blood agar containing 1 microg/ml of tylosin was investigated. Carbadox was the most active (MIC: < 0.00625) of all the antimicrobial agents. Although all the isolates were susceptible to tylosin, some were resistant to erythromycin. Tiamulin, lincomycin and dimetridazole were also very active against the isolates. All the resistant isolates did not harbor any plasmids. In vitro selected tylosin-resistant mutants of previously tylosin-susceptible isolates showed a new mutation in which their adenine at the base position equivalent to 2062 of 23S rDNA of Escherichia coli has been replaced by cytosine. These findings may both provide guidance towards the proper choice of antimicrobial agents for the treatment of canine intestinal spirochetosis, and add to the understanding of the genetic basis of tylosin resistance.