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1.
The honeybee compound eye is equipped with ultraviolet, blue, and green receptors, which form the physiological basis of a
trichromatic color vision system. We studied the distribution of the spectral receptors by localizing the three mRNAs encoding
the opsins of the ultraviolet-, blue- and green-absorbing visual pigments. The expression patterns of the three opsin mRNAs
demonstrated that three distinct types ommatidia exist, refuting the common assumption that the ommatidia composing the bee
compound eye contain identical sets of spectral receptors. We found that type I ommatidia contain one ultraviolet and one
blue receptor, type II ommatidia contain two ultraviolet receptors, and type III ommatidia have two blue receptors. All the
three ommatidial types contain six green receptors. The ommatidia appear to be distributed rather randomly over the retina.
The ratio of type I, II, and III ommatidia was about 44:46:10. Type III ommatidia appeared to be slightly more frequent (18%)
in the anterior part of the ventral region of the eye. Retinal heterogeneity and ommatidial randomness, first clearly demonstrated
in butterflies, seems to be a common design principle of the eyes of insects. 相似文献
2.
Tong Huang Motohiro Miura Shogo Nobukawa Masayuki Yamaguchi 《Journal of Polymers and the Environment》2014,22(2):183-189
Effect of the addition of poly(ethylene glycol) terminated by benzoate (PEG-BA) on the crystallization behavior and dynamic mechanical properties of poly(l-lactic acid) PLLA is studied as compared with poly(ethylene glycol) (PEG-OH). It is found that PEG-BA is miscible with PLLA and shows good plasticizing effect. Because PEG-OH having the same degree of polymerization is immiscible with PLLA, the end group in PEG-BA, i.e., benzoate, plays an important role in the miscibility. Furthermore, PEG-BA does not induce the PLLA degradation at melt-processing, whereas PEG-OH leads to the hydrolysis degradation. Finally, the addition of PEG-BA pronounces the crystallization rate of PLLA at low crystallization temperatures and thus enhances the degree of crystallinity at conventional processing. Consequently, the temperature dependence of dynamic mechanical properties are similar to that for isotactic polypropylene. 相似文献
3.
Change in a bacterial population during the process of degradation of a phytoplankton bloom was investigated at Lake Hamana, Japan in June 1981. The predominant phytoplankton were Prorocentrum micans Ehrenberg and P. triestinum Schiller. While most phytoplankton cells were living and moving actively, most bacteria were those in a free-living state (free-living bacteria) and the number of bacteria associated with particulate materials (attached bacteria) was less than a few percent of the total bacterial number. As the decline process proceeded, the number of free-living bacteria remained almost constant or decreased slightly; on the other hand, the number of attached bacteria increased gradually and reached about 40% of the total bacterial number. These results indicate that some of the free-living bacteria become attached to particulate organic matter and grow on the surface of the particles. 相似文献
4.
Batch photocatalytic degradation of 1000-ppm gaseous perchloroethylene (PCE) was conducted with UV irradiation such that nearly 100% was decomposed within 10 min. The main intermediate and final product were identified as trichloroacetylchloride (TCAC) and hydrogen chloride (HCl), respectively, and minor ones as dichloroacetic acid (DCAC), monochloroacetic acid (MCAC), carbon tetrachloride, chloroform, and phosgene. More than 90% of Cl- equivalent, i.e., the sum of the chlorine number in PCE, intermediates, and HCl, was compensated for during the time of PCE degradation; a result indicating that no other major chlorinated intermediates are present during the time of PCE degradation. In a similar experiment, 500 ppm of gaseous TCAC degraded into HCl within 3 h without producing DCAC or MCAC, where like PCE, more than 90% of Cl- equivalent, i.e., the sum of the chlorine number in TCAC and HCl, was compensated for during time of TCAC degradation. Accordingly, gaseous PCE is concluded to predominantly follow a degradation pathway of PCE --> TCAC --> HCl. 相似文献
5.
Pharmacophagous acquisition of clerodendrins by the turnip sawfly (Athalia rosae ruficornis) and their role in the mating behavior 总被引:3,自引:0,他引:3
Summary. Adults of the turnip sawfly, Athalia rosae ruficornis (Tenthredinidae: Hymenoptera), frequently visit a plant, Clerodendron trichotomum (Verbenaceae), and feed pharmacophagously on the glandular trichomes on the leaf surface. A series of neo-clerodane diterpenoids (e.g. clerodendrins B and D) contained in glandular organs on the leaf surface stimulate feeding of the sawflies (both males and
females). The adults fed selectively on the trichomes were found to sequester a series of the bitter-tasting diterpenes (clerodendrin
D, ajugachin A, athaliadiol) in the body tissues, which suggested their primary role as defense substances against predators.
Females fed on Clerodendron leaves or on clerodendrin B or D were more successful in mating than unfed females. Thus, females seem to obtain an advantage
in mating success through the acquisition of the defensive principles from the Clerodendron plant.
Received 20 April 1999; accepted 29 June 1999 相似文献
6.
Cathryn L. Abbott Rhonda L. Millikin Mark J. Hipfner Scott Hatch Motohiro Ito Yutaka Watanuki Theresa M. Burg 《Marine Biology》2014,161(2):275-283
Data from eight microsatellite markers screened in 246 rhinoceros auklets (Cerorhinca monocerata) from across the North Pacific revealed multiple genetic groups. The east (North America) to west (Japan) split was clearly evident in all analyses. Within the eastern Pacific, a minimum of three genetic groups are present. Surprisingly, rhinoceros auklets from Triangle Island, British Columbia, were genetically isolated from other nearby populations, including the breeding colony on Pine Island (~100 km to the east). A fourth genetic cluster (Chowiet Is) was detected using principal coordinate’s analysis; however, sample sizes were limited. Patterns of differentiation correspond to nonbreeding distributions with the eastern and western Pacific birds spending time off the west coast of North America and Japan, respectively, and may represent historical isolation in separate refugia during the Pleistocene glaciations. The patterns of genetic structure result from a combination of historical and contemporary factors influencing dispersal of rhinoceros auklets. 相似文献
7.
Effects of Nitrogen Supply on the Sensitivity to O3 of Growth and Photosynthesis of Japanese Beech (Fagus crenata) Seedlings 总被引:1,自引:0,他引:1
Masahiro Yamaguchi Makoto Watanabe Naoki Matsuo Junichi Naba Ryo Funada Motohiro Fukami Hideyuki Matsumura Yoshihisa Kohno Takeshi Izuta 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):131-136
To obtain basic information for evaluating critical levels of O3 under different nitrogen loads for protecting Japanese beech forests, two-year-old seedlings of Fagus crenata Blume were grown in potted andisol supplied with N as NH4NO3 solution at 0, 20 or 50 kg ha−1 year−1 and exposed to charcoal-filtered air or O3 at 1.0, 1.5 and 2.0 times the ambient concentration from 16 April to 22 September 2004. The O3 induced significant reductions in the whole-plant dry mass, net photosynthetic rate at 380 μmol mol−1 CO2 (A
380), carboxylation efficiency (CE) and concentrations of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and total soluble protein (TSP) in the leaves.
The concentrations of Rubisco and TSP were negatively correlated with the concentration of leaf acidic amino acid, suggesting
that O3 enhanced the degradation of protein such as Rubisco. The N supply to the soil did not significantly change the whole-plant
dry mass and A
380, whereas it significantly increased the CE and concentrations of Rubisco and total amino acid. No significant interactive effects of O3 and N supply to the soil were detected on the growth, photosynthetic parameters and concentrations of protein and amino acid
in the leaves. In conclusion, N supply to the soil at ≤50 kg ha−1 year−1 does not significantly change the sensitivity to O3 of growth and net photosynthesis of Fagus crenata seedlings. 相似文献
8.
This study examined the effects of four situational factors on the severity of punishment chosen by a manager following a rule infraction. Two attributes of the offender, gender and performance history, and two outcomes of the infraction, physical damage and personal injury, were combined within a scenario evaluated by 421 graduate business students in a 2 × 2 × 2 × 2 ANOVA design. Results indicated strong main effects for performance history, physical damage, and personal injury but not for gender. Further analyses indicated that the gender composition of the superior/offender dyad did not have a significant effect on the severity of discipline, although some variation occurred across dyads. These results imply that superiors are likely to base disciplinary judgements on situational factors, and that situational factors affect superiors' decisions in a simple, linear fashion. 相似文献
9.
H.?Fukami M.?Omori K.?Shimoike T.?Hayashibara M.?HattaEmail author 《Marine Biology》2003,142(4):679-684
In Okinawa, Japan, we found several species of the coral genus Acropora that spawn 1.5-3 h earlier than other mass-spawning acroporids. In six early-spawning species, gamete bundles appear on the surface of the colony ("setting") about 1 h before sunset, whereas setting occurs about 1 h after sunset in the more common late mass spawners. These early spawners are divided further into two sub-groups: three species that release their gametes within 1 h after setting and three that release their gametes 1.5-2 h after setting. DNA phylogenetic analyses show that each of these groups forms an independent genetic clade. These genetic relationships suggest that different spawning times form the basis of reproductive isolation among these broadcast-spawning corals. Late spawning appears to be the ancestral state, and the shift of spawning to earlier times may have played a role in the speciation process in these sympatric species. 相似文献
10.
Motohiro Morishima 《组织行为杂志》1995,16(6):609-625
Previous research on Japanese union members has documented occupational differences in employees' attitudes toward union organizations (Japan Productivity Center, 1990; Morishima, 1993). Yet, little has been done to examine why these differences occur. This study examines, using a data set obtained in 1987 from about 4000 employees, the correlates of union loyalty across white-collar and blue-collar occupations, and among white-collar occupations. A model is developed from previous research on employees' attitudes toward union organizations and on Japanese industrial relations. The results obtained by OLS analyses of union loyalty correlates—members' judgements of union contributions to improvements in employment outcomes and of employers' human resource policies—indicate that Japanese unions have benefited mainly blue-collar workers and traditional white-collar workers, such as those in administrative positions, relative to those in technical positions. 相似文献