Taurine transporter from the giant Pacific oyster <Emphasis Type="Italic">Crassostrea gigas</Emphasis>: function and expression in response to hyper- and hypo-osmotic stress

ABSTRACT:   Taurine is the primary osmolyte in marine molluscs, whose cellular osmo-conforming process is vital for environmental adaptation because of a lack of osmotic homeostasis. Here, cDNA cloning and expression, and functional analyses of taurine transporter (TAUT) from the giant Pacific oyster are reported on. The deduced amino-acid sequence of oyster TAUT (oyTAUT) showed 47–51% identity to those of vertebrate TAUT, whereas identity among the vertebrates is 78–95%. Functional analysis of oyTAUT expressed in Xenopus oocytes revealed that oyTAUT has a lower affinity and specificity for taurine and a requirement for higher NaCl concentration, compared with vertebrate TAUT. Taken together with similar functional properties of TAUT from mussel, indicated by our previous study, it is possible that these functional features reflect the internal environment of the molluscs (i.e. higher taurine and NaCl concentrations). Oyster taurine transporter mRNA expression was induced by not only hyper-osmotic stress, similar to other TAUT, but also hypo-osmotic stress. It is speculated that the expression in response to hypo-osmotic stress was induced by a substantial decrease in tissue taurine content following the decrease in the internal osmolality.     

Nitrocapsanthin and nitrofucoxanthin, respective products of capsanthin and fucoxanthin reaction with peroxynitrite

The in vitro reactivity of capsanthin (1) and fucoxanthin (2) with peroxynitrite was investigated, and the reaction products produced by scavenging with peroxynitrite were analyzed. (14'Z)-Nitrocapsanthin (3) and 12-nitrocapsanthin (4) were isolated from the products of the reaction of capsanthin with peroxynitrite. Similarly, (14Z)-15-nitrofucoxanthin (5), (11Z)-11-nitrofucoxanthin (6), and (14Z,9'Z)-15-nitrofucoxanthin (7) were obtained from the reaction of peroxynitrite reaction with fucoxanthin. Capsanthin and fucoxanthin inhibited the nitration of tyrosine by peroxynitrite. Furthermore, nitrocapsanthins (3 and 4) and nitrofucoxanthins (5 and 6) exhibited an inhibitory effect on Epstein-Barr virus early antigen activation in Raji cells and an antiproliferative effect on human pancreatic carcinoma. Moreover, nitrocapsanthins (3 and 4) inhibited carcinogensis of mouse skin tumors initiated by 7,12-dimethylbenz[a]anthracene (DMBN).     

Identification of Trichoderma SKT-1, a biological control agent against seedborne pathogens of rice

Trichoderma SKT-1 was previously reported as a powerful biological control agent against seedborne pathogens of rice, but the taxonomic disposition of the fungal isolate was not clear. Trichoderma SKT-1 produced irregular pyramidal warts on conidia and had an optimum growth temperature of 30°C. Morphological characteristics and colony growth were identical to those of known species of Trichoderma, including the newly recognized species T. asperellum. The 5.8S rDNA with the internal transcribed spacer (ITS) region (ca. 514 bp) of the fungus was compared with those of known species to determine the phylogenetic placement of the fungus. The length and sequence of the regions from Trichoderma SKT-1 were completely identical to those of an isolate of T. asperellum NRRL 5242 (AJ230669). On the basis of these results, we concluded that Trichoderma SKT-1 was T. asperellum.     

Estimation of daily urinary potassium excretion using urinary creatinine as an index substance in prepartum dairy cows

In the present study, the daily excretion of potassium (K) in urine (urinary K(UK)) was estimated from a 6 h urine sample using urinary creatinine (UC) as the index substance. All urine was collected from six pregnant Holstein cows at 6 h intervals for 24 h on 3 days of the 4th, 2nd and final week before the expected date of parturition. In total, 72 6 h urine samples were obtained. Daily UC excretion (mg/day per kg bodyweight (BW)) was almost the same for the three sampling days. Daily UC excretion varied among cows from 22.1 to 24.3 mg/day per kg BW with a mean of 22.8 mg/day per kg BW with no significant difference. Thus, daily UC excretion was confirmed to be constant throughout the prepartum period with no differences among individuals. The concentration ratios of K to creatinine ((UK mg/dL)/(UC mg/dL) (UK/UC)) correlated strongly to the hourly K excretions (mg/h per kg BW) (r = 0.952, P < 0.01) in the 6 h urine samples. The differences in the UK/UC ratio between sampling periods were not significant within each cow. Therefore, daily UK excretion (mg/day) can be estimated using the equation: daily UK excretion (mg/day) = daily UC excretion (mg/day per kg BW) × BW (kg) × 6 h urine sample UK/UC, where daily UC excretion can be a given value.     

An epidemiological survey of Chrysanthemum chlorotic mottle viroid in Akita Prefecture as a model region in Japan

In epidemiological surveys on Chrysanthemum chlorotic mottle viroid (CChMVd) in various chrysanthemums cultivated in Akita Prefecture, Japan, in 2002–2005, approximately 20% of cultivars harbored CChMVd, including more symptomatic types than nonsymptomatic. Large-flowered cultivars were less frequently infected than small-flowered and spray types. The number of CChMVd-infected chrysanthemums is increasing, and the disease is found throughout major chrysanthemum-producing districts. Chrysanthemums infected only with CChMVd, in general, had no noticeable symptoms of disease. Most of those dually infected with known viruses and/or viroid also had no symptoms characteristic of chlorotic mottle disease. The lack of noticeable symptoms in major Japanese cultivars may have resulted in the unnoticed spread of the viroid.     

猪隐秘杆菌型出血性坏死性脾炎

六月龄去势公猪表现昏睡、食欲不振、站立困难。尸检发现脾脏边缘呈多重出血灶。从脾脏、肾脏、肌肉和肝脏中分离出革兰氏阳性杆菌,对分离株(TO16177)的16S rDNA基因序列比较分析发现,其可能与未发表过的隐秘杆菌属HJ57-14E菌株(登记号:gi18873551)(比较675bp个碱基,相似性达99.7%)为同一个属。脾脏组织切片的组织学检查发现呈广泛性坏死和炎症,其中革兰氏阳性杆菌显而易见。肝脏中可见多病灶的坏死斑。免疫组织化学检测发现,分离株与抗化脓性隐秘杆菌属(Arcanobacterium pyogenes)和内氏放线菌(Actinomyces naeslundii)的多克隆抗体具有交叉反应,且与后者的交叉反应更强烈。相似的反应也见于扁桃体的化脓灶中分离株,偶尔也见于脾脏和淋巴结中的分离株。本研究结果表明,这种未公开发布的隐秘杆菌属的细菌会引起生长肥育猪多器官功能衰竭,而后继发急性出血性坏死性脾炎。     

Video tracking analysis of behavioral patterns during estrus in goats

Here, we report a new method for measuring behavioral patterns during estrus in goats based on video tracking analysis. Data were collected from cycling goats, which were in estrus (n = 8) or not in estrus (n = 8). An observation pen (2.5 m × 2.5 m) was set up in the corner of the female paddock with one side adjacent to a male paddock. The positions and movements of goats were tracked every 0.5 sec for 10 min by using a video tracking software, and the trajectory data were used for the analysis. There were no significant differences in the durations of standing and walking or the total length of movement. However, the number of approaches to a male and the duration of staying near the male were higher in goats in estrus than in goats not in estrus. The proposed evaluation method may be suitable for detailed monitoring of behavioral changes during estrus in goats.     

Bait method to detect Pythium species that grow at high temperatures in hydroponic solutions

Pythium helicoides, P. aphanidermatum and P. myriotylum are important pathogens that cause root rot of several crops in hydroponic culture and in ebb-and-flow irrigation systems. These species belong to a group of Pythium species that can grow at temperatures higher than 40°C. We developed a method for baiting these high-temperature Pythium species and evaluated its practicality to monitor their presence in nutrient solutions. Seeds of cucumber, tomato, radish, hemp, perilla and millet and leaves of bent grass and rose were tested as baits in hydroponic systems. Hemp, perilla and radish seeds and bent grass and rose leaves were more effective than the other baits for Pythium zoospores, and bent grass leaves were the most effective. In a sensitivity test, bent grass leaf traps (BLTs) detected three Pythium species after only a 1 day exposure to suspensions of 40 zoospores per liter of water, and the frequency of detection increased with zoospore density and with baiting period. A temperature of 38°C was optimum for the selective reisolation of the high-temperature Pythium species from the BLTs. The BLT was also tested with inoculated and noninoculated miniature roses that shared a recirculating nutrient solution. The pathogen was detected in the nutrient solution 23 days before the disease spread to the noninoculated roses. In addition, P. helicoides was detected 30 days before the disease was evident in a commercial greenhouse. The baiting method described here will be useful for monitoring high-temperature Pythium species in recirculating hydroponic culture systems.     

Physiological Races and Vegetative Compatibility Groups of Fusarium oxysporum f. sp. lactucae Isolated from Crisphead Lettuce in Japan

One hundred and sixteen isolates of Fusarium oxysporum f. sp. lactucae obtained from 85 fields in three crisphead lettuce-producing areas in Nagano Prefecture, Japan were typed for races using differential cultivars Patriot, Banchu Red Fire and Costa Rica No. 4. They were also grouped into vegetative compatibility groups (VCGs) using complementation tests with nitrate non-utilizing (nit) mutants. Two California strains reported as F. oxysporum f. sp. lactucum, a type culture of F. oxysporum f. sp. lactucae, and 28 avirulent isolates of F. oxysporum obtained from crisphead lettuce were included for comparison. Among Nagano isolates, 66 isolates were identified as race 1, and 50 as race 2. Race 1 strains derived from Shiojiri and Komoro cities and race 2 from Kawakami village and Komoro city. All isolates of race 2 were biotin auxotrophs, and the race could be distinguished based on its requirement for biotin on minimal nitrate agar medium (MM). Pathogenic isolates were classified into two VCGs and three heterokaryon self-incompatible isolates. Strong correlations were found between race and VCG. All the race 1 strains were assigned to VCG 1 except self-incompatible isolates, and all the race 2 strains to VCG 2. The 28 avirulent isolates of F. oxysporum were incompatible with VCG 1 and VCG 2. California strains was vegetatively compatible with VCG 1, and they were assigned to race 1. Based on vegetative compatibility, these two races of F. oxysporum f. sp. lactucae may be genetically distinct, and F. oxysporum f. sp. lactucae race 1 is identical to F. oxysporum f. sp. lactucum. Received 7 May 2002/ Accepted in revised form 6 September 2002