Molecular characterization of Blastocystis isolates from children and rhesus monkeys in Kathmandu, Nepal

To investigate the possible transmission of Blastocystis organisms between local rhesus monkeys and children in Kathmandu, Nepal, we compared the subtype (ST) and sequence of Blastocystis isolates from children with gastrointestinal symptoms and local rhesus monkeys. Twenty and 10 Blastocystis isolates were established from 82 and 10 fecal samples obtained from children and monkeys, respectively. Subtype analysis with seven sequence-tagged site (STS) primers indicated that the prevalence of Blastocystis sp. ST1, ST2 and ST3 was 20%, 20% and 60% in the child isolates, respectively. In contrast to human isolates, ST3 was not found in monkey isolates and the prevalence of ST1 and ST2 was 50% and 70%, respectively, including three mixed STs1 and 2 and one isolate not amplified by any STS primers, respectively. Since Blastocystis sp. ST2 has been reported as the most dominant genotype in the survey of Blastocystis infection among the various monkey species, sequence comparison of the 150 bp variable region of the small subunit rRNA (SSU rRNA) gene was conducted among ST2 isolates of humans and monkeys. Sequence alignment of 24 clones developed from ST2 isolates of 4 humans and 4 monkeys showed three distinct subgroups, defined as ST2A, ST2B and ST2C. These three subgroups were shared between the child and monkey isolates. These results suggest that the local rhesus monkeys are a possible source of Blastocystis sp. ST2 infection of humans in Kathmandu.     

National surveillance of Salmonella enterica in food-producing animals in Japan

A total of 518 fecal samples collected from 183 apparently healthy cattle, 180 pigs and 155 broilers throughout Japan in 1999 were examined to determine the prevalence and antimicrobial susceptibility of Salmonella. The isolation rates were 36.1% in broilers, 2.8% in pigs and 0.5% in cattle. S. enterica Infantis was the most frequent isolate, found in 22.6% of broiler fecal samples. Higher resistance rates were observed against oxytetracycline (82.0%), dihydrostreptomycin (77.9%), kanamycin (41.0%) and trimethoprim (35.2%). Resistance rates to ampicillin, ceftiofur, bicozamycin, chloramphenicol and nalidixic acid were <10%. CTX-M-2 β-lactamase producing S. enterica Senftenberg was found in the isolates obtained from one broiler fecal sample. This is the first report of cephalosporin-resistant Salmonella directly isolated from food animal in Japan.     

Molecular epidemiological analysis of bat rabies viruses in Brazil

A molecular epidemiological analysis was performed in 19 rabies viruses (RVs) isolated from haematophagous, frugivorous and insectivorous bats, in Sao Paulo, Brazil. The authors carried out RT-PCR for amplification of the RV nucleoprotein (N) gene, and determined 1,335 nucleotide sequences of N gene by direct sequencing method. Phylogenetic analysis, which was based on the N gene of Brazilian RV isolates identified presently and previously, revealed that RVs isolated from bats were genetically divided into four lineages had a tendency to depend on the host bat species. The first lineage consisted mainly of haematophagous bat (Desmodus rotundus) isolates, including frugivorous bat (Artibeus spp.) isolates. Other three lineages consisted of insectivorous bat isolates; mainly Eptesicus spp., Molossus spp. and Nyctinomops spp. isolates, respectively. These results indicate a possibility of that there are bat species-specific RV variants in Brazil.     

Enrichment for isolating Salmonella Choleraesuis and other Salmonella spp. from pigs

The growth of Salmonella Choleraesuis was examined in Rappaport Vassiliadis broth (RV) and Hajna-tetrathionate broth (HTT) at 37 and 42 degrees C. As the enrichment in RV at 37 degrees C was satisfactory for isolating S. Choleraesuis, we used this enrichment for isolation from the samples collected from 15 asymptomatic pigs reared on a S. Choleraesuis contaminated farm. S. Choleraesuis was frequently isolated from six pigs (40.0%) under field conditions. The isolation of other Salmonella serovars than S. Choleraesuis was attempted by using both RV enrichment at 37 degrees C and HTT enrichment at 42 degrees C. Salmonella organisms were isolated from 156 (44.8%) of 348 fecal samples and more frequently with HTT at 42 degrees C (43.4%) than with RV at 37 degrees C (20.9%). If other serovars in addition to S. Choleraesuis are to be surveyed, HTT enrichment should be used in combination with RV enrichment.     

Acute hepatitis in a piglet experimentally inoculated with tissue homogenates from pigs with postweaning multisystemic wasting syndrome

Five 2 day-old colostrum-deprived piglets were inoculated with tissue homogenates from pigs with postweaning multisystemic wasting syndrome. One of the five piglets developed icterus and died 23 days post-inoculation. Histologic examination revealed acute hepatitis. Porcine circovirus type 2 (PCV-2) antigen and nucleic acid were detected in hepatocytes and phagocytic cells. Ultrastructurally, hepatocytes and phagocytic cells had large numbers of cytoplasmic inclusions, which were composed of electron-dense paracrystalline arrays of small non-enveloped viral particles approximately 17 nm in diameter. Apoptotic hepatocytes were confirmed by the TUNEL method and electron microscopic examination. These findings may indicate that hepatocellular necrosis is associated with replication of PCV-2. Apoptosis of hepatocytes also contributes to the pathogenesis of hepatic lesions in this case.     

Leydig cell hyperplasia in an ENU-induced mutant mouse with germ cell depletion

Repro22 is an N-ethyl-N-nitrosourea (ENU)-induced mutation in mice showing depletion of both male and female germ cells. In the present study, we investigated the male phenotypes of the mutant mouse at the adult stage. The repro22/repro22 homozygous mice showed reduced body weights as well as markedly reduced testis weights. Histological examination of the testes at 4 and 10 months of age showed no germ cells in the seminiferous tubules of the affected testis while a number of Sertoli cells were observed in the tubules. In addition to the germ cell depletion, the testes of the affected mouse contained expanded intertubular spaces that were filled by Leydig cell-like interstitial cells. These interstitial cells were confirmed to be Leydig cells by immunohistochmical staining using anti-3beta-HSD antibody. The estimated number of Leydig cells in the affected testes at 10 months of age increased approximately 2 fold compared with those of normal testes. Furthermore, the plasma testosterone levels of the affected mice at 10 months of age were significantly higher than those of the normal mice. These findings indicated that the repro22/repro22 mouse developed hyperplasia of Leydig cells that was presumably caused by the absence of germ cells in the seminiferous tubules.     

Pedigree analysis of factor XI deficiency in Japanese black cattle

Using a DNA-based diagnostic test for factor XI deficiency in Japanese black cattle, we surveyed 123 cattle (42 sires and 81 dams) in Gifu and Hyogo prefectures, and calculated gene frequencies. In sires, we drew up the pedigree network of the cattle with the factor XI deficiency. Results showed that the mutated allele of factor XI deficiency was retroactive in at least 6 or more generations of sires. Frequencies of the mutant gene were higher at 26.4% in total, and at 33.3% in sires. All 7 cattle with the homozygote of mutated allele were clinically normal, and showed no bleeding episodes. The mutated allele of factor XI deficiency might be widespread among Japanese black cattle.     

Antimicrobial susceptibilities, serogroups, and molecular characterization of avian pathogenic Escherichia coli isolates in Japan

In total, 83 avian pathogenic Escherichia coli (APEC) isolates from avian colibacillosis during a period from 2001 to 2006 in Japan were investigated for serogroups, typical virulence factors, antimicrobial susceptibility, and genetic relatedness. The most common serogroup was O78 (30.1%); 80.7% of isolates harbored the iss gene and 55.4% of isolates harbored the tsh gene. Antimicrobial resistance of the isolates was found for ampicillin (77.1%), oxytetracycline (75.9%), kanamycin (36.1%), fradiomycin (33.7%), trimethoprim (25.3%), enrofloxacin (21.7%), and florfenicol (6.0%). Although multiple antimicrobial-resistant phenotypes (three or more antimicrobials) accounted for 54.2% of isolates, no isolate exhibited resistance to all agents tested. The fluoroquinolone-resistant isolates had point mutations in GyrA (Ser83 --> Leu, Asp87 --> Asn) and ParC (Ser80 --> Ile, Glu84 --> Gly). Of 18 enrofloxacin-resistant E. coli isolates, nine isolates belonged to serotype O78. In PFGE analysis, eight of the nine enrofloxacin-resistant O78 isolates were classified into an identical cluster. This suggests that a specific genotype of fluoroquinolone-resistant O78 APEC may be widely distributed in Japan.     

Insect midgut structures and molecules as targets of plant‐derived protease inhibitors and lectins

The midgut of insects is involved in digestion, osmoregulation and immunity. Although several defensive strategies are present in this organ, its organization and function may be disturbed by some insecticidal agents, including bioactive proteins like lectins and protease inhibitors (PIs) from plants. PIs interfere with digestion, leading to poor nutrient absorption and decreasing amino acid bioavailability. Intake of PIs can delay development, cause deformities and reduce fertility. Ingestion of PIs may lead to changes in the set of proteases secreted in the insect gut, but this response is often insufficient and results in aggravation of the malnutrition status. Lectins are proteins that are able to interact with glycoconjugates, including those linked to cell surfaces. Their effects on the midgut include disruption of the peritrophic matrix, brush border and secretory cell layer; induction of apoptosis and oxidative stress; interference with nutrient absorption and transport proteins; and damaging effects on symbionts. In addition, lectins can cross the intestinal barrier and reach the hemolymph. The establishment of resistant insect populations due to selective pressure resulting from massive use of a bioactive protein is an actual possibility, but this can be minimized by the multiple mode‐of‐action of these proteins, mainly the lectins. © 2018 Society of Chemical Industry     

Response of juvenile pacu (Piaractus mesopotamicus Holmberg, 1887) to balanced digestible protein

This 45‐day work aimed to determine the response of juvenile pacu (Piaractus mesopotamicus) to balanced digestible protein (BDP) and to use these responses to determine whether the optimum economic levels of BDP would differ depending on the form in which the fish is sold. Six isoenergetic diets containing 163, 201, 238, 272, 315 and 348 g/kg BDP (dry‐matter basis) were prepared through the serial dilutions of a high‐protein diet with the low‐protein diet. Fish (initial average body weight, 10.82 ± 0.14 g) were fed with respective experimental diets three times a day until apparent satiation. The optimum biological level of BDP was calculated as 326 g/kg (dry‐matter basis) by the quadratic regression model for maximum body weight gain of juvenile pacu. To maximize economic returns (US$/kg) for different end products, the optimum economic levels of BDP were calculated as 311, 317 and 319 g/kg (dry‐matter basis) by an economic model for whole‐body, eviscerated and sliced juvenile pacu respectively. This finding revealed that obtaining maximum biological performance of fish in the case of high feed costs or low prices of the end product in consumer market would substantially reduce the economic returns.