Evaluation of truncated LipL32 expressed by Escherichia coli and Pichia pastoris for serodiagnosis of Leptospira infection in rodents

The applicability of the recombinant LipL32 for serodiagnosis of leptospiral infection in field rodents was assessed in this study. An immunodominant region of LipL32 was determined by monoclonal antibodies, and then, truncated LipL32 (tLipL32) was designed to contain the region (87–188th amino acid). The tLipL32 was compared between two recombinant expression hosts Escherichia coli and Pichia pastoris in ELISA. With field rat sera, tLipL32 expressed by P. pastoris (tLipL32p) had high antigenicity without background reactions, while tLipL32 expressed by E. coli (tLipL32e) showed high background reactions, which were reduced by pre-adsorption of sera with E. coli. To evaluate tLipL32-ELISA, field rat sera were tentatively divided into a Leptospira infection positive (12 sera) and a negative group (12 sera) based on the results from flaB gene PCR of kidney samples and WB with whole Leptospira cell. Consequently, the sensitivity of tLipL32p-ELISA for field rat sera was 83% . A similar result was obtained from tLipL32e-ELISA with adsorbed sera, (92%). However, sensitivity of tLipL32e-ELISA using sera without an adsorption treatment was 50%. Regardless of the expression host, tLipL32-ELISA had 100% specificity and sensitivity in experimentally infected laboratory rats. These results suggest that recombinant LipL32 expressed by P. pastoris is more applicable for serodiagnosis in field rats due to a lack of background reaction.     

Goat milk acceptance and promotion methods in Japan: The questionnaire survey to middle class households

A consumer questionnaire conducted with the purpose of ascertaining the acceptability of goat milk and related products in Japan was carried out on 345 guarantees of Nippon Veterinary and Life Science University in December 2006. 275 effective responses (79%) representing middle class urban households were returned. The results revealed that (1) 30% of respondents have experienced drinking goat milk and only 10% are aware of the current retail situation of goat milk and related products; (2) over 70% of goat milk drinkers raised goats by hand at some point in their past and their first experience drinking goat milk was in infancy; (3) those with experience in drinking goat milk expressed a vague evaluation and minimal understanding of drinking goat milk; (4) respondents who were inexperienced goat milk drinkers expressed a strong desire to taste and a weak desire to purchase goat milk; (5) respondents expressed low recognition regarding retailed goat milk products, but those who had already purchased goat milk products expressed a high evaluation and strong desire to purchase these products again; and (6) recognition of goat milk characteristics is low, but those with high recognition also rate goat milk highly. Goats are perceived as being 'mild and familiar.' It is necessary for those who manage goat husbandry to present goat milk and related product tasting opportunities to consumers. The key point is to make the functional differences between cow and goat milk clear and present the advantages of goat milk at the fore of this promotion. Goat milk should not be promoted merely as a drink that is similar to cow milk, but must be positioned as a functional drink or health food in order to expand the Japanese goat milk market.     

Partial characterization and ontogenetic development of pancreatic digestive enzymes in Japanese eel Anguilla japonica larvae

The pancreatic digestive enzymes, trypsin, chymotrypsin, lipase and amylase were partially characterized, and changes in their activities were examined during the initial ontogeny of Japanese eel Anguilla japonica larvae from 5 to 34 days post-hatching (dph). The pH optima of the eel larval enzymes were narrower than those other fish species; trypsin activity was highest at pH 9, chymotrypsin and amylase activities were highest at pH 7 and 8, and lipase activity was highest at pH 8 and 9. In an analysis of thermal profiles, the larval pancreatic enzymes had a high optimal temperature and high thermal stability, which are typical of fish from the tropics. At 12 and 13 dph, lipase activity and gene expression levels of trypsin (-a and -b), lipase and amylase decreased markedly, suggesting a marked change in larval metabolism at that time. These data could be useful in the development of artificial larval diets in Japanese eel.     

A comparative analysis of acceptance by Japanese females and price of goat milk from different sources

A sensory survey was carried out using 4 different types of whole goat milk among middle‐class females to investigate consumer acceptability of goat milk and whether there is an opportunity to expand the sale of goat milk products in Japan. Four different types of whole milk powder (domestic concentrate‐fed, domestic pasture‐fed, USA commercially canned, and New Zealand commercially canned) were used. Fresh cow milk was served as a control. Thirty‐one housewives evaluated the 5 liquid milk samples for smell, taste and overall characteristics on a scale of 1 (low) to 3 (high). Chi‐square analyses were carried out to detect significant differences between the milk types in each category. The goat milk from the USA was the most preferred goat milk with respect to smell and overall evaluation. Domestic pasture‐fed milk received the lowest grade in the evaluation for its ‘grassy and goaty’ smell. This result shows us that pasture intake affects the taste and smell of powdered milk which gives the lowest evaluation by the participants. If Japanese goat milk producers want to be successful in the domestic goat milk market and compete against goat milk products from other countries, they should improve production methods and flavor of their products.     

Pigs as an experimental model for systemic Mycobacterium avium infectious disease

Mycobacterium avium complex (MAC) is an opportunistic pathogen in AIDS patients and pigs, and causes dissemination through primary intestinal lesions. However, its pathogenesis is not well understood. In this article, we hypothesize that pigs can provide a suitable experimental model of disseminated MAC disease. We compared the initial route of infection, the characteristics of the pathogenic strains, the immunological status of the hosts, and the histological characteristics. The route of infection and infective strains are similar in AIDS patients and pigs. Pigs can respond to infection by the formation of systemic epithelioid granuloma with sufficient cell-mediated immunity. However, there are differences in immunological status and histological features between AIDS patients and pigs. Therefore, pigs might be used as an appropriate animal model because of their good cell mediated immunity triggered by systemic mycobacterial infection. In conclusion, MAC infections in AIDS patients and pigs show similarities in terms of the initial route of infection and the genetic characteristics of the pathogenic strains.     

Nitrogen fixation of Sesbania rostrata: Contribution of stem nodules to nitrogen acquisition

Abstract

Nitrogen contents, nodule numbers, and nodule dry weights of 6-week-oId Sesbania rostrata plants grown in sand culture with only root nodules, only stem nodules or with both were compared and the root nodules were found to contribute to nitrogen acquisition more significantly than the stem nodules. Similar findings were obtained in ¹⁵N₂-fixing experiments. An 8-week-old plant with both stem and root nodules fixed 1.50 mg nitrogen in a 12 h light period, while the fixation decreased to 1.15 mg nitrogen after the removal of the stem nodules, suggesting that root nodules played major role in nitrogen fixation. However, acetylene-reducing activities per nodule dry weight were higher in the stem nodules. Under flooding conditions, the aerenchyma tissues contributed to about 40% of N₂ transport to root nodules, and 60% was supplied through stem.     

Uronic acid in humus

Introduction

Uronic acids are aldehydic sugar acids. In nature, they are composed mainly of d-glucuronic acid and d-galacturonic acid and scarcely of dmannuronic acid.     

Relationship between zooplankton abundance and the early marine life history of juvenile chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis> in eastern Hokkaido,Japan

Interannual variations in abundance, timing of outmigration from rivers, growth rate and condition of juvenile chum salmon (Oncorhynchus keta) were studied in the Nemuro Strait (eastern Hokkaido, Japan) during 1999–2002 to establish a possible relationship to zooplankton abundance. The otolith microstructure of juveniles was examined each year in late June to determine their time and size at sea entry (i.e., outmigration), and to estimate the early marine growth rates. Salmon outmigration peaked in mid- or late May, which coincided, in three of the four study years, with the peak release of juveniles into rivers within the study area. Abundance, growth rate and condition of fish were higher in 2001, when—compared to other years—smaller fish experienced higher growth rates, coinciding with greater zooplankton abundance for that year. Our results suggest that high zooplankton abundance positively influenced juvenile chum salmon growth and the condition of the fish during their early marine life despite their small size at sea entry.     

Guanine-cytosine contents of the host and symbiont cDNA in a symbiotic coral

ABSTRACT:   Hermatypic (reef-building) corals harbor dinoflagellate endo-symbionts Symbiodinium spp. In studying gene expression in such symbiotic corals, problems arise regarding how to distinguish the coral and symbiont mRNA, and how to estimate their fractions in the mRNA population of the holobiont (symbiotic complex of the coral and Symbiodinium cells). In this study, these issues were addressed using juveniles of hermatypic coral Acropora tenuis in symbiosis with Symbiodinium cells of strain PL-TS-1. First, the guanine-cytosine (GC) contents were determined in expressed sequence tags (EST) from PL-TS-1 cells cultured in vitro and symbiont-free larvae of A. tenuis , and their average GC contents were found to be significantly different. The average GC content of the EST from the holobiont was much closer to that of A. tenuis larvae, suggesting that the majority (>90%) of mRNA isolated from the holobiont originated in the host. In protein-coding sequences, little overlap was observed between the GC-content distributions of PL-TS-1 cells and A. tenuis larvae. All of the coding sequences ( n  = 59) found in the A. tenuis EST had GC contents below 0.5, whereas the GC content exceeded 0.5 in the majority (43/44) of coding sequences from the nuclear genome of PL-TS-1 cells.