Soft rot of Peruvian carrot due to Erwinia carotovora in Brazil

Peruvian carrot soft rot occurs quite frequently in Minas Gerais State, Brazil, either under field conditions or after harvested roots have been stored. The etiology of the disease was investigated and the disease was found to be induced by Erwinia carotovora. This appears to be the first report of this disease.     

Cuneiform blight-a new bacterial disease of Tanier spinach

Tanier spinach ( Xanthosoma brasiliense , Araceae) is a common leafy vegetable in south-eastern Brazil. A cuneiform leaf blight which started at the edges of leaves and resulted in complete leaf decay has recently been observed. The causal agent was identified as Pseudomonas cichorii. This appears to be the first report of the disease.     

Gastrointestinal motor disturbance in rabbits experimentally infected with Strongyloides papillosus

Strongyloides papillosus is a common nematode in ruminants, and the rabbit is the only susceptible experimental animal that has been identified to date. It is known that heavy infection with S. papillosus causes death in a number of animals. However, even though a number of fatal cases have been reported, the mechanism by which S. papillosus infection leads to death remains unknown. In this study, the pathogenic effect of S. papillosus infection on gastrointestinal motility in infected rabbits was investigated by radiographic means. Gastrointestinal motility in rabbits experimentally infected with S. papillosus was assessed by contrast radiography after oral administration of barium sulfate on days 11 (group A) and 13 (group B) of infection. Body weight, food intake, fecal weight and egg count per gram of feces (EPG) were examined in order to investigate the effect of infection on gastrointestinal motility. Seven rabbits from each S. papillosus-infected and uninfected group were examined. Significant declines in body weight, daily food intake, and fecal weight, as well as gastrointestinal motor disturbances, were observed in association with elevated EPG counts in infected rabbits. This was only observed during the intestinal phase of S. papillosus infection. These results suggest that gastrointestinal motor disturbances underlie the anorexia, weight loss and subsequent death observed in rabbits infected with adult stage S. papillosus.     

Determination of optimal conditions for parthenogenetic activation and subsequent development of rat oocytes in vitro

The present study was undertaken to determine optimal conditions for parthenogenetic activation and subsequent development of rat oocytes. Oocytes from immature Wistar-Imamichi (WI) and Sprague Dawley (SD) rats were activated by electrical stimulation in combination with 6-dimethylaminopurine (6-DMAP) to assess whether different rat strains display different responses to activation treatment. Since the cleavage rates of activated oocytes were significantly higher in WI than SD strain rats, WI rats were used for the subsequent experiments to determine the effects of post-hCG time, culture duration, different activation protocols (electrical stimulation with 6-DMAP or ionomycin with 6-DMAP) and osmolarity of the activation medium on the activation and subsequent development of WI rat oocytes. For oocytes activated by electrical stimulation combined with 6-DMAP, the percentages of oocytes that were activated and that developed to blastocysts were higher when oocytes were collected at 18-20 h than at any other time points after hCG injection (16, 22-24 h). Culturing for 2-6 h before activation treatment markedly decreased the percentage of activated oocytes that developed to beyond the four-cell stage. There were no differences in the percentages of oocytes with pronuclear formation and subsequent development to the two-cell and blastocyst stages between oocytes that were activated by electrical stimulation or ionomycin, both followed by 6-DMAP treatment. Activation of oocytes by ionomycin and 6-DMAP, both in low osmolarity media (246 mOsM), markedly increased the cleavage rates and percentages of high quality blastocysts (71%). The optimal conditions determined in the present study with simplified activation protocols and high efficiency of activation and subsequent development of WI rat oocytes will be helpful for further research involving nuclear transfer in the rat.     

Virulence of ophiostomatoid fungi associated with the spruce bark beetleIps typographus f.japonicus in Yezo spruce

Yezo spruce trees (Picea jezoensis), approximately 40-year-old were inoculated with eight ophiostomatoid fungi associated withIps typographus f.japonicus to compare relative virulence of the fungi. Among them,Ophistoma penicillatum formed the longest necrotic lesion on inner bark around inoculation points, followed byO. aenigmaticum, Ceratocystis polonica, andO. bicolor, whileC. polonica formed a larger dry zone in sapwood than the other fungi. Yezo spruce trees were also mass inoculated withC. polonica, O. penicillatum, O. piceae singly or mixed to demonstrate the ability of the fungi to kill Yezo spruce trees. The trees inoculated withC. polonica, O. penicillatum or the mixed inoculum showed discoloration of needles in the early summer of the next year and died by autumn. However, the trees inoculated withO. piceae or the control inocula did not die, except for one tree. These results indicated thatC. polonica andO. penicillatum were more virulent thanO. piceae and suggested that they might be at least partially responsible for the mortality of the beetle-infested Yezo spruce trees. Part of this study was supported by the Sumitomo Foundation, Japan to Y. Yamaoka and I. Takahashi. Part of this study was presented at the 107th meeting of the Japanese Forestry Society, April 1–4, 1996, Tsukuba, Ibaraki, at the 42nd annual meeting of the Mycological Society of Japan, May 16–17, 1998, Kyoto, and at the 110th meeting of the Japanese Forestry Society, April 2–5, 1999, Matsuyama, Ehime. Contribution No. 143, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Contraceptive effect of a gonadotropin-releasing hormone vaccine on a captive female African Lion (Panthera leo): a case study

Lions (Panthera leo) breed well under captivity, so contraception has been commonly conducted for population management, leading to a demand for a less invasive and reversible contraceptive approach in lions. In this study, we examined the efficacy of a commercial gonadotropin-releasing hormone vaccine as a method of suppressing reproductive activity in a sexually matured female lion. Under behavioral restraint, the vaccine was injected twice (days 0 and 109). After the initial vaccination, ovarian activity is still observed. After the second vaccination, contraceptive effect was confirmed for 246 days until restart of estrous cycles. We confirmed only a slight swelling around the injection site after the second vaccination. This study may suggest an alternative option for a contraceptive method in lions.     

Regulation of biosynthesis,perception, and functions of strigolactones for promoting arbuscular mycorrhizal symbiosis and managing root parasitic weeds

Strigolactones (SLs) are carotenoid‐derived plant secondary metabolites that play important roles in various aspects of plant growth and development as plant hormones, and in rhizosphere communications with symbiotic microbes and also root parasitic weeds. Therefore, sophisticated regulation of the biosynthesis, perception and functions of SLs is expected to promote symbiosis of beneficial microbes including arbuscular mycorrhizal (AM) fungi and also to retard parasitism by devastating root parasitic weeds. We have developed SL mimics with different skeletons, SL biosynthesis inhibitors acting at different biosynthetic steps, SL perception inhibitors that covalently bind to the SL receptor D14, and SL function inhibitors that bind to the serine residue at the catalytic site. In greenhouse pot tests, TIS108, an azole‐type SL biosynthesis inhibitor effectively reduced numbers of attached root parasites Orobanche minor and Striga hermonthica without affecting their host plants; tomato and rice, respectively. AM colonization resulted in weak but distinctly enhanced plant resistance to pathogens. SL mimics can be used to promote AM symbiosis and to reduce the application rate of systemic‐acquired resistance inducers which are generally phytotoxic to horticultural crops. © 2019 Society of Chemical Industry     

Molecular typing of Salmonella enterica serovar Enteritidis isolates from food-producing animals in Japan by multilocus variable-number tandem repeat analysis: evidence of clonal dissemination and replacement

Background

Salmonella enterica serovar Enteritidis is a zoonotic pathogen. Human infections are associated with contaminated eggs and egg products. In Japan, since 1989, the incidence of food-borne disease caused by S. Enteritidis has increased and a pandemic has occurred; however, little is known about changes that occurred before and after this pandemic event in the dominant lineage of isolates from food-producing animals. This study aimed to determine the S. Enteritidis lineages in Japan over the last few decades by using multilocus variable-number tandem repeat analysis (MLVA).

Findings

MLVA was used to analyse 79 S. Enteritidis isolates collected from chickens (n = 63), cattle (n = 12), pigs (n = 2), and goats (n = 2) during 1975–2009. The S. Enteritidis isolates showed 14 different MLVA allele combinations, which were classified into two major clusters (A and C) and a minor cluster (B). All the 62 isolates in cluster A were isolated after 1988, whereas 13 of the 17 isolates belonging to cluster B and C were isolated before 1989.

Conclusions

The MLVA results showed that cluster C was predominant before 1989, and isolates in cluster A disseminated since 1989 and replaced the previous dominant clone, suggesting that isolates of cluster A originated from imported S. Enteritidis infection.