Juvenile hormone delays the initiation of rectal sac distention by disrupting ecdysteroid action in the silkworm, Bombyx mori

Holometabolous insects develop without feeding and excreting during the pupal period and thus require repository organs for metabolic waste, or meconium. The rectal sac is an organ for storing meconium during pupal-adult development of holometabolous insects. Although the rectal sac has an essential function, hormonal and developmental regulation of waste-accumulation and the consequences of rectal sac distention are still unknown. In the silkworm, Bombyx mori, the rectal sac distends with meconium in the middle pupal period under the regulation of ecdysteroid. Here, we show that juvenile hormone analog (JHA) delayed rectal sac distention and disturbed adult emergence. Distention was not restored completely by an injection of 20-hydroxyecdysone (20E) into pupae applied with JHA, suggesting that JHA suppresses 20E action and delays the timing of ecdysteroid elevation. Thus the “status quo” action of JHA may function in two different ways during pupal-adult development.     

Antibody response against Trichinella spiralis in experimentally infected rats is dose dependent

ABSTRACT: Domestic pigs are the main representatives of the domestic cycle of Trichinella spiralis that play a role in transmission to humans. In Europe, backyard pigs of small household farms are the most important risks for humans to obtain trichinellosis. Rats might play a role in the transmission of Trichinella spiralis from domestic to sylvatic animals and vice versa. In order to be able to investigate the role of wild rats in the epidemiology of T. spiralis in The Netherlands, we studied the dynamics of antibody response after T. spiralis infections in experimental rats, using infection doses ranging from very low (10 muscle larvae, ML, per rat) to very high (16 000 ML per rat). To evaluate the feasibility of rats surviving high infection doses with T. spiralis, clinical and pathological parameters were quantified. Serological tools for detecting T. spiralis in rats were developed to quantitatively study the correlation between parasite load and immunological response. The results show that an infection dose-dependent antibody response was developed in rats after infection with as low as 10 ML up to a level of 10 000 ML. A positive correlation was found between the number of recovered ML and serum antibody levels, although specific measured antibody levels correspond to a wide range of LPG values. Serum antibodies of rats that were infected even with 10 or 25 ML could readily be detected by use of the T. spiralis western blot 2 weeks post infection. We conclude that based on these low infection doses, serologic tests are a useful tool to survey T. spiralis in wild rats.     

Establishment of a new cell-based assay to measure the activity of sweeteners in fluorescent food extracts

Taste receptors have been defined at the molecular level in the past decade, and cell-based assays have been developed using cultured cells heterologously expressing these receptors. The most popular approach to detecting the cellular response to a tastant is to measure changes in intracellular Ca(2+) concentration using Ca(2+)-sensitive fluorescent dyes. However, this method cannot be applied to food-derived samples that contain fluorescent substances. To establish an assay system that would be applicable to fluorescent samples, we tested the use of Ca(2+)-sensitive photoproteins, such as aequorin and mitochondrial clytin-II, as Ca(2+) indicators in a human sweet taste receptor assay. Using these systems, we successfully detected receptor activation in response to sweetener, even when fluorescent compounds coexisted. This luminescence-based assay will be a powerful tool to objectively evaluate the sweetness of food-derived samples even at an industry level.     

Theoretical turnover rate of the rumen liquid fraction in dairy cows and its relationship to feed intake,rumen fermentation,and milk production

Ruminant animals are able to convert plant materials (grain and the human‐indigestible portion of carbohydrates) to milk and meat. In this conversion, most of the plant materials are digested by rumen fermentation and are changed to short‐chain fatty acids, microbial cells, and methane, which is released into the atmosphere. The relationships among feed, rumen fermentation, and milk production are poorly understood. Here we report a novel indicator of characteristics of rumen fermentation, theoretical turnover rate (TTOR) of the rumen liquid fraction. The TTOR was calculated from the presumed rumen volume (PRV) which is estimated by dividing the methane yield by the methane concentration of rumen fluid. The formula for the TTOR is: TTOR = PRV/body weight^0.75. Our present analyses confirm that the TTOR as an indicator is capable of connecting feed, rumen fermentation, and milk production, because dry matter intake/TTOR showed a strong correlation with milk yield/TTOR. In addition, the TTOR may be related to ruminal pH, as we observed that the ruminal pH decreased as the TTOR increased. We propose that the TTOR is a factor characterizing rumen fermentation and a good indicator of the productivity of ruminants and dysbiosis of the rumen microbiome.     

Improvement and evaluation of the feller-buncher head

The high quality forest machines have recently become very popular in Japan. Many improvements on these machines have been made to fit the Japanese forests. This report describes the improvement and evaluation of the feller-buncher head of the prototype machine: FG-35. This head is mounted on the telescopic and knuckle-boom carrier. The prototype machine was improved to cut the trees, felled down on the ground or felled side ways by the storm as in the Kyushu district. And also the machine was improved so that it could be driven well without crashing the chainsaw-bar by the beginners. The testing operation of this machine carried out in Sumita-chou in Iwate and in Kuzu-chou in Oita. The productivity of the machine can be estimated at about 20 m³/h. The results of the improvement on the machine can be said to be good. A portion of this report was presented at the 106th Annual Meeting of the Japanese Forestry Society (1995).     

Transmission risk of human trichinellosis

Trichinella is a food-borne parasitic zoonoses and human cases are still reported in Europe mainly due to the consumption of pig meat originating from small backyard farms. Infections originating from industrialized pig farming have not been reported for decades in Europe, due to control measures to prevent the transmission of Trichinella from wildlife by indoor housing and good management practices. Therefore, risk-based monitoring programs might replace individual carcass control in industrialized pig farming as described in EU legislation SANCO 2075/2005. Transmission of Trichinella species between wildlife and the risk that may pose to humans via consumption of contaminated pork meat has not been studied quantitatively. One pathway by which human trichinellosis can occur is the rat–pig–human route. To evaluate the transmission risk though this pathway the dose responses of rat, pig, and human were studied. Experimental T. spiralis infection was performed in rats with doses of as few as 10 parasites and the data set was analysed using a newly developed dose response model that describes larvae per gram (LPG). Experimental T. spiralis infection in pig was analysed in a similar way. Furthermore nine published outbreaks of human trichinellosis were analysed to determine the dose response in humans. The risk of human trichinellosis via the rat–pig–human transmission was simulated by the Monte Carlo method. A pair of female and male parasites representing the lowest infection pressure from the environment, led to the probability of human trichinellosis by consumption of 100 g of raw pork meat equal to 5% via the studied rat–pig–human pathway. In the absence of rodent control near the farm, a low infection pressure from wildlife presents a relatively high risk of human trichinellosis via consumption of uncooked pork meat.     

First case report of Sarcocystis neurona-induced equine protozoal myeloencephalitis in Japan

Equine protozoal myeloencephalitis developed in a three-year-old male Thoroughbred racehorse imported from the United States. The animal showed astasia five days after the onset of ataxia. Histopathologically, focal nonpurulent myelitis accompanied by hemorrhage and perivascular infiltration was observed in the fourth and fifth cervical spinal cord. Immunohistochemically, shizonts were occasionally observed and were positive for anti-Sarcocystis neurona (S. neurona) antiserum. S. neurona-specific antibodies were detected in the serum and cerebrospinal fluid by Western blot. This is the first equine protozoal myeloencephalitis case in Japan.     

Silicone allergy associated with intraocular silicone ball prosthesis in a dog

A 13-year-old, male Pomeranian dog was presented for scleral rupture with intraocular hemorrhage and retinal detachment in the right eye. After intrascleral silicone ball prosthesis, recurrent swelling and granulomatous blepharitis were observed for 140 d and finally melting keratitis developed. Although an intraorbital prosthesis was implanted, recurrent, serious, erosive, and ulcerative blepharitis developed with high plasma C-reactive protein concentrations. Since the blepharitis could not be controlled, the silicone ball was removed and the affected orbit was debrided. The blepharitis resolved rapidly, and the orbit healed routinely. Positive allergic reactions to silicone were discovered through a patch test.Key clinical message:To the authors’ knowledge, this is the first report on silicone allergy in a dog with positive allergic reactions to silicone in the patch test.     

Genetic selection for resistance to mycoplasmal pneumonia of swine (MPS) in the Landrace line influences the expression of soluble factors in blood after MPS vaccine sensitization

We recently developed a Landrace line that is resistant to mycoplasmal pneumonia of swine (MPS) infection by genetic selection for five generations, and we reported that the immunophenotype of this line is different from that of the non‐selected line in terms of changes in peripheral blood leukocyte population after MPS vaccination. This study followed up previous findings demonstrating changes in soluble factors in blood, namely, hormones, Mycoplasma hyopneumoniae‐specific immunoglobulin G (IgG), and cytokines. These two lines were injected with MPS vaccine on days ?7 and 0 after blood sampling on those days, and blood samples were collected on days ?14, ?7, 0, 2, 7 and 14. We found changes in the levels of many hormones and cytokines in both lines. However, we found that only growth hormone (GH) and interferon (IFN)‐γ levels were statistically different between these two lines. GH concentration was reduced (day 0) and IFN‐γ concentration was increased (day 14) in the MPS‐selected line compared with the non‐selected line, despite unchanged IFN‐γ messenger RNA expression in blood cells. Although detailed mechanisms underlying these phenotypes remain unsolved, these traits would be useful to improve MPS resistance in pig production and provide an insight into MPS infection.