Antibody response to toxic shock syndrome toxin-1 of Staphylococcus aureus in dairy cows

Antibody response to toxic shock syndrome toxin-1 (TSST-1) of Staphylococcus aureus in dairy cows was examined by enzyme linked immunosorbent assay (ELISA). Serum antibody to TSST-1 was not detected in 39 (76.5%) of 51 calves, which were 1-6 months of age. In contrast, TSST-1 antibody was demonstrated in 1728 (72.6%) of 2380 lactating cows housed on 36 dairy farms. The ELISA values of antibody ranged from 0.2 to 3.0 OD and presented a distribution with the peak at 1.6 OD. The mean ELISA value differed between farms, and it increased slightly along with parturient history. Somatic cell counts of milk from 174 lactating cows was compared with TSST-1 antibody and tst1,000,000 cells per ml. The mean ELISA values in milk were lower than those of sera, but they rose as somatic cells increased. The tst gene of S. aureus detected in 76.0-86.2% of the milk samples containing somatic cells > 500,000 cells per ml, a level which indicates mastitis. The data suggests that many lactating cows may be infected by TSST-1- producing S. aureus.     

Identification of Petunia hybrida cultivars that diurnally emit floral fragrances

In order to identify genetic resources for breeding fragrant petunias for use as bedding plants, volatile compounds released by day from the flowers of 40 commercial Petunia hybrida cultivars were analyzed using a solid-phase micro-extraction technique coupled with GC–MS. The three cultivars with solid deep-blue flowers that accumulate malvidin in corollas with high tissue pH were found to emit abundant iso-eugenol as the principal floral fragrance. Several other cultivars that emitted considerable amounts of methylbenzoate and/or benzylbenzoate from the flower were also identified. Association between the floral fragrance and the other floral traits such as floral anthocyanin composition and corolla-tissue pH was discussed.     

Enhancement of photosynthesis and growth of tomato seedlings by forced ventilation within the canopy

A forced ventilation system that directs airflow upward or downward within a canopy was developed for plant culture in order to enhance photosynthesis and growth of the plant canopy. Tomato seedling canopies including the seedlings, growing medium, and a plastic tray were used for the experiments. In the upward and downward ventilation systems, air flows upward and downward, respectively, within the plant canopy; this is achieved by blowing and drawing air from holes (Ø 6 mm) made in plastic pipes positioned on the surface of the growing medium. A horizontal airflow system was used as a conventional system to compare the performance of the experimental ventilation systems. Using the upward and downward ventilation systems, the effects of air directions and air velocities on the CO₂ exchange rate of the tomato seedling canopy and the growth of the seedlings were compared with those observed using the conventional horizontal airflow system. The forced ventilation within the plant canopy enhanced the CO₂ exchange rate of the canopy and the dry masses of the seedlings by 1.4–1.5 and 1.2–1.3 times, respectively, as compared to the conventional horizontal airflow. When the leaf area index (LAI) increased from 1.2 to 2.4, there was only a 5% decrease in the CO₂ exchange rate per unit leaf area in the downward ventilation system, whereas there was a 20% decrease in the CO₂ exchange rate per leaf area in the horizontal airflow system. The coefficient of variation for the dry mass of the seedlings was higher in the downward system than in the other systems. These results demonstrate that forced ventilation within the canopy is an effective technique to enhance the gas exchange of the plant canopy and the consequent plant growth.     

Aloe ring spot,a new disease of aloe caused by <Emphasis Type="Italic">Haematonectria haematococca</Emphasis> (Berk. &; Broome) Samuels &; Nirenberg (anamorph: <Emphasis Type="Italic">Fusarium</Emphasis> sp.)

A ring spot disease of Aloe vera was found on leaves of potted seedlings of Aloe vera in Hachijojima and Chichijima Islands, Tokyo. From tissue of ring spot lesions, a fungus producing Fusarium-type conidia was consistently isolated. After 1 month, reddish perithecia of nectriaceous fungus had formed on the colonies of this isolate on PDA. These nectriaceous and Fusarium fungi were identified as Haematonectria haematococca and Fusarium sp., respectively. From a single ascospore isolation, the former was confirmed to be the teleomorph of the Fusarium sp. Typical ring spot lesions were reproduced by artificial inoculations using single ascospore and single conidium isolates. Inoculations of five species of genus Aloe revealed that they were highly susceptible except for A. arborescens. This is the first report of a disease on Aloe caused by H. haematococca (anamorph: Fusarium sp.) in Japan, and it was named aloe ring spot.     

Differences in the behavior of the crossbred steers of different sire lines of Japanese Black cattle

We determined differences in the behavior of the progeny of two major sire lines of Japanese Black cattle by recording the behavior of 35 and 70 half-sib steers of sires from fast (FG) and slow (SG) growing lines, respectively. Two sire lines of steers were mixed and allocated to nine pens with 11–12 animals per pen. The proportion of steers lying was significantly (P < 0.001) higher in the SG line (43.4 ± 5.7% compared to 40.3 ± 6.0%). The proportion of time spent eating concentrate feed (FG: 12.1 ± 2.3%; SG: 11.4 ± 2.1%), drinking (FG: 0.8 ± 1.1%; SG: 0.4 ± 0.6%), licking the feed trough (FG: 0.4 ± 0.6%; SG: 0.2 ± 0.4%) and performing tongue-playing (FG: 3.1 ± 4.6%; SG: 1.0 ± 1.9%) was significantly higher in FG, whereas the proportion of time spent resting (FG: 41.5 ± 12.8%; SG: 43.7 ± 10.9%) and performing self-licking (FG: 1.7 ± 1.4%; SG: 2.1 ± 1.3%) was higher in SG (all P < 0.05). These results show progeny of the FG sire engaged in more active behaviors compared to the progeny of the SG sire line.     

Quantitative structure-activity studies of substituted benzyl chrysanthemates: 7. Relationship between induction of repetitive discharges and effects on the action potential

The effects of substituted benzyl (1R)-trans-chrysanthemates and related compounds on the action potential of the crayfish giant axon were investigated using an intracellular microelectrode. The effects are broadly classified into three types: deceleration of the falling-phase of the action potential (type A), elevation of the depolarizing after-potential (type B), and the combination type (type C). The potency of the type A compounds to decelerate the rate of the falling-phase was determined in terms of the concentration required for reducing the rate to a specified degree. This potency was shown to correlate with the potency to induce repetitive discharges in the cockroach central nerve cord in terms of minimum effective concentration, which was determined previously. The potency of the types B and C compounds to elevate the after-potential was, however, not related directly with the cockroach nerve repetitive activity. The elevation of the after-potential is one of the critical factors but other effects such as a depolarization of the resting potential may be involved in determining the repetitive activity.     

Metabolism of fenitrothion by organophosphorus-resistant and -susceptible house flies, Musca domestica L

The metabolism of fenitrothion was investigated in highly resistant (Akita-f) and susceptible (SRS) strains of the house fly, Musca domestica L. The Akita-f strain was 3500 times more resistant to fenitrothion than the SRS strain. Fenitrothion, topically applied to the flies, was metabolized in vivo far faster in the Akita-f strain than in the SRS strain. In vitro studies revealed that fenitrothion was metabolized by a cytochrome P-450-dependent monooxygenase system and glutathione S-transferases. The former oxidase system metabolized fenitrothion in vitro into fenitrooxon and 3-methyl-4-nitrophenol as major metabolites, and into 3-hydroxymethyl-fenitrothion and 3-hydroxymethyl-fenitrooxon as minor metabolites. Glutathione S-transferases metabolized fenitrothion into desmethylfenitrothion. The cytochrome P-450-dependent monooxygenase system and glutathione S-transferases of the resistant Akita-f strain had 1.4 to 2.2 times and 9.7 times, respectively, as great activities as those of the susceptible SRS strain. These results suggest the importance of glutathione S-transferases in fenitrothion resistance in the Akita-f strain.     

Electroencephalogram of Japanese Black calves affected with cerebrocortical necrosis

Electroencephalogram (EEG) examinations were carried out on three Japanese Black calves (1, 2 and 14 week old) affected with cerebrocortical necrosis (CCN) in order to investigate the relationship between EEG abnormalities and encephalic lesions. Some neurologic signs such as circling, astasia, convulsion and opisthotonus appeared in two of the calves (case 1 and 3). The other calf (case 2), however, showed no neurologic signs. The EEGs obtained from the two calves (case 1 and 2), in the awake state, showed constant high amplitude (50-160 microV) and slow (1-4 Hz) activity (HASA). One of these (case 1) had necrosis mainly in the right hemisphere and showed a markedly asymmetric sharp wave. On the other hand, in case 3, the EEG showed diffuse lowered activity, and almost flat in some leads. A decrease in fast activity observed in common with all three animals. These findings suggest that one of the characteristic EEG patterns of CCN patient may be HASA and decreased fast activity. Histopathologic diagnoses of the calves were CCN in various degrees. The degrees of abnormality of the EEGs seemed to accord with the seriousness of the lesions. Because the EEG obtained from the calf having no obvious neurologic signs showed an abnormal pattern, it was considered that EEG examinations in the early stages of disorders are valuable to diagnose CCN.