Early life survival is critical to successful replenishment of fish populations, and hypotheses developed under the Growth-Survival Paradigm (GSP) have guided investigations of controlling processes. The GSP postulates that recruitment depends on growth and mortality rates during early life stages, as well as their duration, after which the mortality declines substantially. The GSP predicts a shift in the frequency distribution of growth histories with age towards faster growth rates relative to the initial population because slow-growing individuals are subject to high mortality (via starvation and predation). However, mortality data compiled from 387 cases published in 153 studies (1971–2022) showed that the GSP was only supported in 56% of cases. Selection against slow growth occurred in two-thirds of field studies, leaving a non-negligible fraction of cases showing either an absence of or inverse growth-selective survival, suggesting the growth-survival relationship is more complex than currently considered within the GSP framework. Stochastic simulations allowed us to assess the influence of key intrinsic and extrinsic factors on the characteristics of surviving larvae and identify knowledge gaps on the drivers of variability in growth-selective survival. We suggest caution when interpreting patterns of growth selection because changes in variance and autocorrelation of individual growth rates among cohorts can invalidate fundamental GSP assumptions. We argue that breakthroughs in recruitment research require a comprehensive, population-specific characterization of the role of predation and intrinsic factors in driving variability in the distribution and autocorrelation of larval growth rates, and of the life stage corresponding to the endpoint of pre-recruited life. 相似文献
In melon (Cucumis melo L.), the amount of fertile pollen decreases at low temperature during winter and early spring and thereby restricts fertilization. A promising way to overcome this problem is to develop parthenocarpic cultivars. Parthenocarpic cucumber and squash, but not melon cultivars are available. In this study, we explored 172 accessions from an East Asian melon collection and identified accessions that exhibited strong parthenocarpic ability throughout the year. Crosses between parthenocarpic accessions and a non-parthenocarpic cultivar, and among parthenocarpic accessions indicated that parthenocarpy may be inherited in a recessive manner and is likely controlled by the same gene or genes in these accessions. The parthenocarpic indices, such as the size and number of parthenocarpic fruits, differed among the cultivation periods, indicating the importance of environmental factors for parthenocarpic fruit development. We conclude that it is possible to breed new cultivars with stable parthenocarpic ability throughout the year by using the identified accessions. 相似文献
The chemical conversion of phenolized sulfuric acid lignin (P-SAL), prepared from sulfuric acid lignin (SAL) by phenolation
with sulfuric acid catalyst, to novel cationic surfactant was investigated. To elucidate the chemical reactivity of the P-SAL
to a Mannich reaction, 1-guaiacyl-1-p-hydroxyphenylethane (I) as a simple phenolized sulfuric acid lignin model compound was reacted with dimethylamine and formaldehyde. Quantitative
analysis of the products by gas-liquid chromatography suggested that the p-hydroxyphenyl nucleus was more reactive than the guaiacyl nucleus. The Mannich reaction of SAL with dimethylamine did not
yield a soluble cationic surfactant, but P-SAL produced water-soluble cationic surfactant in a quantitative yield. The Mannich
reaction products (MP-SAL) of P-SAL had 1,3-dimethylaminomethyl groups/C9-C6. The results of the surface tension measurements showed that the decrease in surface tension of MP-SAL was much larger than
that of lignosulfonate as a commercial surfactant from lignin.
Received: February 13, 2002 / Accepted: June 12, 2002
Acknowledgments The authors thank Nippon Paper Industries Co. and Lion Corp. for providing the commercial products and Dr. K. Aoi (Graduate
School of Bioagricultural Sciences, Nagoya University, Japan) for advising us on the measurement of surface tension. This
research was conducted with the support of a Grant-in-Aid for Scientific Research (11460079) from the Ministry of Education,
Culture, Sports, Science and Technology of Japan.
Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002
Correspondence to:Y. Matsushita 相似文献
In this study, we examined factors that affected milk production by cows raised in a temperate climate area. We conducted this study on a large dairy farm containing approximately 2000 Holstein cows, located in a temperate climate area. We collected 7803 calving records for 4069 cows from 2012 to 2016. We then assessed the effect of hot weather on milk yield by examining three climate factors: season, maximum temperature (MAX), and the temperature and humidity index (THI). We found that increases in heat stress caused linear decreases in milk yield (P?<?0.05). Additionally, the effects of the three climate factors on milk yield varied depending on cow parity and days open (P?<?0.05). Thus, management procedures should consider cow parity and lactating stage to minimize the negative effects of heat stress on milk production. We also found that the lowest Akaike information criterion value was obtained in our model when using THI for 305-day milk yield. This suggests that THI is a more accurate variable for evaluating heat stress than MAX or season.
We surveyed the distribution of red sea bream eggs between 2006 and 2010 in the east Seto Inland Sea to determine the location of the spawning grounds and the characteristics of preferred spawning habitats. We identified early-development stage red sea bream eggs using a monoclonal antibody assay. The early-development stage eggs were present in waters around Awaji Island (AW area) and around Ieshima Island, Shodo Island, and Bisan Seto (collectively the ISB area). The mean red sea bream egg density in the AW area was not significantly different from that in the ISB area. Based on the locations where we observed early-development stage eggs and the density of eggs, the ISB and AW areas appeared to be the primary spawning grounds in the east Seto Inland Sea during the survey period. A quotient analysis suggested that spawning fish had clear preferences for physical conditions. The areas suitable for spawning appear to be those with sandy substrate at a depth of 30–70 m. The temperature range suitable for spawning was between 16.5 and 21.5 °C. 相似文献
Soft feces and a decreased delivery rate were observed in a specific-pathogen-free (SPF) C3H-scid mouse breeding colony. Grossly, the ceca were shrunken and edematous in the affected mice. Histopathologically, severe edema in the cecal submucosa as well as infiltration of inflammatory cells in the lamina propria and submucosa of the ceca and colon were observed. No pathogenic microorganisms were detected by the routine microbiological tests. By anaerobic bacterial-examination, Clostridium (C.) difficile with toxin A was isolated from the cecal contents of the affected mice. The mice were diagnosed with C. difficile-associated colitis. This case appears to be the first report of natural infection with C. difficile in SPF mice with clinical signs. 相似文献
Methanol extract of sawdust of sugi (Cryptomeria japonica) heartwood was fractionated with toluene and n-hexane to give solvent-soluble and solvent-insoluble fractions. The n-hexane-soluble fraction showed the most inhibition activity among the fractions against phytopathogenic microorganisms, namely
Fusarium oxysporum, Phytophthora capsici, Pythium splendens, and Ralstonia solanacearum. Sandaracopimarinol and ferruginol, isolated from the n-hexane-soluble fraction, showed moderate antifungal activity against the three fungi and strong antibacterial activity against
R. solanacearum. The content of sandaracopimarinol (7.07 g/kg based on the dried sawdust) in the heartwood was about twice that of ferruginol.
Sandaracopimarinol and ferruginol strongly inhibited the growth of Gram-positive bacteria but did not show inhibitory action
against Gram-negative bacteria except for R. solanacearum. The antibacterial effect of sandaracopimarinol was first found in the present study and was stronger than that of ferruginol. 相似文献
Nonphenolic β-O-4 lignin substructure model dimer, 1,3-dihydroxy-2-(2,6-dimethoxyphenoxy)-1-(4-ethoxy-3-methoxyphenyl)propane (I) was degraded by horseradish peroxidase (HRP) in the presence of hydrogen peroxide and 1-hydroxybenztriazole (HBT). 4-Ethoxy-3-methoxybenzoic
acid (II), 1-(4-ethoxy-3-methoxyphenyl)-3-hydroxypropanone (III), 2,3-dihydroxy-1-(4-ethoxy-3-methoxyphenyl)-1-formyloxypropane (IV), 2,3-dihydroxy-1-(4-ethoxy-3-methoxyphenyl)propanone (V), 1-(4-ethoxy-3-methoxyphenyl)-1,2,3-trihydroxypropane (VI), 1-(4-ethoxy-3-methoxyphenyl)-1,2,3-trihydroxypropane-2,3-cyclic carbonate (VII), and 1-(4-ethoxy-3-methoxyphenyl)-1,2,3-trihydroxypropane-1,2-cyclic carbonate (VIII) were identified as degradation products by gas chromatography-mass spectrometry. These degradation products were qualitatively
the same as those of substrate I in the laccase/HBT system, but the yield of the products was apparently different. The products catalyzed by the HRP/H2O2/HBT system contained large amounts of the aromatic ring cleavage products IV, VII, and VIII compared with those catalyzed by the laccase/HBT system, while the amount of Cα-Cβ cleavage product II is relatively low. These results suggest that the role of HBT is not in a simple one-electron transfer between the enzymes
and substrates. 相似文献
To assess the possible utility of a fungal gene for manganese-dependent peroxidase (MnP) produced by a transgenic plant in
phytoremediation, we transformed hybrid aspen with a chimeric gene for MnP. Our gene construct allowed expression of the gene
for MnP in plants and relatively high MnP activity was detected in the hydroponic medium in which roots of plants that expressed
the transgene had been cultured. Some of our transgenic plants were able to remove bisphenol A from the medium more efficiently
than wild-type plants. Our results demonstrate that, without any modification of the coding sequence, a chimeric gene for
fungal MnP can be expressed in a woody plant, with secretion of active MnP from roots into the rhizosphere. Our strategy suggests
new options using woody plants for phytoremediation. 相似文献