Dynamics of gonadosomatic index of fish with indeterminate fecundity between subsequent egg batches: application to Japanese anchovy Engraulis japonicus under captive conditions

The gonadosomatic index (GSI) is widely used as a simple measure of reproductive capacity, but its validity has often been questioned. This study showed the inter-spawning variation in the predicted GSI of Japanese anchovy using the gravimetric oocyte packing density method. Time course sampling showed that final oocyte maturation and subsequent ovulation occurred from afternoon to evening on the day of spawning. Oocyte in vitro assay, however, suggested that the timing of the spawning could be predetermined by midnight the day before spawning. Models predicted that the GSI of a female just after spawning gradually increases until the completion of germinal vesicle breakdown, after which it dramatically rises by 24–53 % per hour within a few hours of the onset of ovulation. This indicates that the predicted GSI of a female increases by 3.5 times within about 19 h before ovulation, even if the relative batch fecundity remains constant.     

Comparison of phenylpropanoid volatiles in male rectal pheromone gland after methyl eugenol consumption, and molecular phylogenetic relationship of four global pest fruit fly species: Bactrocera invadens, B. dorsalis, B. correcta and B. zonata

Males of many tephritid fruit fly species of the genus Bactrocera show a very strong affinity to methyl eugenol (ME). An attracted male compulsively ingests ME, which is then biotransformed before its metabolites are accumulated into the rectal gland. The glandular organ is known to serve as a reservoir for sex pheromone in some species. Upon ME-feeding, males of the oriental fruit fly, Bactrocera dorsalis, selectively accumulated two metabolites, 2-allyl-4,5-dimethoxyphenol (DMP) and (E)-coniferyl alcohol (E-CF), in the rectal pheromone gland. We compared the profiles of phenylpropanoid metabolites accumulated by three other species of very high economic and quarantine importance—Bactrocera invadens, Bactrocera zonata and Bactrocera correcta, with that of B. dorsalis. Males of each species were fed artificially on ME and the metabolites stored in the rectal glands were examined by means of chromatography and spectroscopy. Similar to B. dorsalis, males of laboratory-raised B. invadens accumulated DMP and E-CF, in almost equal quantities, in the rectal sac. The sum of DMP and E-CF increased gradually with time after ME consumption and reached as high as 150 μg/male 2 days post ME-feeding. Wild males of B. invadens captured in Kenya also possessed both the compounds in varying quantities. In contrast, males of B. zonata accumulated DMP and (Z)-coniferyl alcohol (Z-CF) in an approximate ratio of 1:1; whereas B. correcta is known to convert ME to (Z)-3,4-dimethoxycinnamyl alcohol (Z-DMC) and Z-CF also in an approximately 1:1 ratio. Thus, there are three types of binary combinations of rectal phenylpropanoid volatiles (i.e. DMP + E-CF; DMP + Z-CF; Z-CF + Z-DMC) utilized among the four Bactrocera species. Such differences in phenylpropanoid ingredients may play a critical role in differentiating these species if encountered in the natural habitat. In this context, the two putative sibling species—B. invadens and B. dorsalis, possess the identical subset of rectal volatiles (DMP and E-CF) in a similar proportion. Furthermore, the phylogenetic analyses of the four Bactrocera species by comparing nucleotide sequences in the mitochondrial genes showed that B. invadens clearly belonged to the same clade as B. dorsalis species. Therefore, we consider the two as the same biological species, and certainly not distinct.     

洪湖水环境现状及主导因子分析

利用2003年夏季在洪湖采集的20个水体样本的测定结果分析了洪湖目前的水体化学性质。根据分析洪湖夏季为Ⅲ类水,则其他季节的水质等级很有可能在Ⅲ类以下。洪湖水体的理化性质各方面状况有利于水生生物的生长和繁殖。运用模糊数学方法得到的结果表明2003年水质状况以Ⅲ类水为主,表明洪湖近年来的水质呈现下降的趋势,这与人类对洪湖水生资源的过度开发有直接的联系;通过主成分分析方法,得到了目前洪湖水质的三个主要控制因素。洪湖水质主要受到氮盐营养元素和生物活动的控制,其次是悬浮物和水体的离子属性,第三是水体的磷化合物。尽管磷是大多数湖泊水体富营养化的关键物质,但它对洪湖湖水而言,并不是最重要的控制因素,所以洪湖富营养化不是水质变化的主要原因。     

Development of a catalytic dehalogenation (Cl,Br) process for municipal waste plastic-derived oil

Dehalogenation is a key technology in the feedstock recycling of mixed halogenated waste plastics. In this study, two different methods were used to clarify the effectiveness of our proposed catalytic dehalogenation process using various carbon composites of iron oxides and calcium carbonate as the catalyst/sorbent. The first approach (a two-step process) was to develop a process for the thermal degradation of mixed halogenated waste plastics, and also develop dehalogenation catalysts for the catalytic dehydrochlorination of organic chlorine compounds from mixed plastic-derived oil containing polyvinyl chloride (PVC) using a fixed-bed flow-type reactor. The second approach (a single-step process) was the simultaneous degradation and dehalogenation of chlorinated (PVC) and brominated (plastic containing brominated flame retardant, HIPS–Br) mixed plastics into halogen-free liquid products. We report on a catalytic dehalogenation process for the chlorinated and brominated organic compounds formed by the pyrolysis of PVC and brominated flame retardant (HIPS–Br) mixed waste plastics [(polyethylene (PE), polypropylene (PP), and polystyrene (PS)], and also other plastics. During dehydrohalogenation, the iron- and calcium-based catalysts were transformed into their corresponding halides, which are also very active in the dehydrohalogenation of organic halogenated compounds. The halogen-free plastic-derived oil (PDO) can be used as a fuel oil or feedstock in refineries.     

Effect of polyethylene terephthalate (PET) on the pyrolysis of brominated flame retardant-containing high-impact polystyrene (HIPS-Br)

Pyrolysis of brominated flame retardant-containing high-impact polystyrene (HIPS-Br) was performed at 430°C in the presence of 0.1 wt% of polyethylene terephthalate (PET) in a Pyrex glass reactor. Two different types of brominated flame retardants (decabromodiphenyl ether and decabromodiphenyl ethane) with or without antimony trioxide (as synergist) 5 wt% were used. The presence of PET had a significant effect on the material balance, decreasing the gaseous product and increasing the residue. The type of flame retardant had no effect on the yield of liquid product; however, the presence of Sb resulted in a marked difference in the distribution of decomposition products. Analysis by a gas chromatograph equipped with a flame ionization detector showed that the hydrocarbons were distributed in the range n-C₇ to n-C₂₅ with major peaks at n-C₉ and n-C₁₇. The presence of PET increased the formation of brominated compounds by several times and affected both the type and quantity of polybrominated compounds. The liquid products obtained from the pyrolysis of HIPS-Br/PET have to be treated before they can be used     

Transport and transformation of sulfur compounds over East Asia during the TRACE-P and ACE-Asia campaigns

On the basis of the recently estimated emission inventory for East Asia with a resolution of 1×1°, the transport and chemical transformation of sulfur compounds over East Asia during the period of 22 February through 4 May 2001 was investigated by using the Models-3 Community Multi-scale Air Quality (CMAQ) modeling system with meteorological fields calculated by the regional atmospheric modeling system (RAMS). For evaluating the model performance simulated concentrations of sulfur dioxide (SO₂) and aerosol sulfate (SO₄²⁻) were compared with the observations on the ground level at four remote sites in Japan and on board aircraft and vessel during the transport and chemical evolution over the Pacific and Asian Pacific regional aerosol characterization experiment field campaigns, and it was found that the model reproduces many of the important features in the observations, including horizontal and vertical gradients. The SO₂ and SO₄²⁻ concentrations show pronounced variations in time and space, with SO₂ and SO₄²⁻ behaving differently due to the interplay of chemical conversion, removal and transport processes. Analysis of model results shows that emission was the dominant term in regulating the SO₂ spatial distribution, while conversion of SO₂ to SO₄²⁻ in the gas phase and the aqueous phase and wet removal were the primary factors that controlled SO₄²⁻ amounts. The gas phase and the aqueous phase have the same importance in oxidizing SO₂, and about 42% sulfur compounds (25% in SO₂) emitted in the model domain was transported out, while about 57% (35% by wet removal processes) was deposited in the domain during the study period.     

Estimating photophysiological condition of endosymbiont-bearing Baculogypsina sphaerulata based on the holobiont color represented in CIE L*a*b* color space

Symbiont-bearing large benthic foraminifers (LBFs) are widely distributed around coral reefs. If the physiological responses of LBFs to environmental changes can be recognized at an individual level, LBFs could serve as highly accurate bioindicators. In this study, chlorophyll a, respiration, and photosynthesis of Baculogypsina sphaerulata individuals were measured, and whether these physiological traits could be estimated based on the color of the holobiont (foraminifera and the diatom symbionts) was examined. Chlorophyll a content was estimated using a* and b* values of holobiont color represented in CIE L*a*b* color space. Photosynthetic performance decreased significantly with increasing whiteness (L*). These results indicated chlorophyll content as well as photosynthetic performance of Baculogypsina could be directly estimated using the holobiont color. The increased whiteness in color and decreased photosynthetic performance were mainly observed under low-light environment, possibly indicating symbiotic algae were shrunk into the central part of the host shell due to prolonged exposure to adverse conditions.     

Co-processing of DVDs and CDs with vegetable cooking oil by thermal degradation

Waste DVDs and CDs were thermally degraded at 450°C by a semibatch process. In total, 40–50 wt% was converted into liquid product that consisted of phenol derivatives (∼75 wt%), bisphenol (∼10 wt%) and its derivatives, and small amounts of aromatic hydrocarbons such as benzene, toluene, ethylbenzene, dimethylbenzene, methylethylbenzene, diethylbenzene, and methylisopropyl benzene. Degradation of the polycarbonate support from DVDs and CDs was enhanced by coprocessing with vegetable cooking oil, the degradation of which gave a homologue series of hydrocarbons and organic acids with up to 25 and 18 atoms of carbon, respectively. Silver from the reflective coating on DVDs and CDs remained in the solid residue, its concentration increasing about 2.5 times compared to that of the original disks.