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311.
Stand structure and natural regeneration of degraded forestland in the northern mountainous region of Vietnam 总被引:1,自引:0,他引:1
Vietnam experienced significant alterations of forest environments during the last half of the twentieth century, and reforestation
efforts have increased since the 1990s. This study developed comparisons of naturally regenerated and plantation forestlands
in northern Vietnam in order to gain a better understanding of reforestation options for the dual objectives of biodiversity
and commercial tree production. Stand structure of secondary natural forest after logging and shifting cultivation were investigated
at two study sites (Hoa Binh Province and Phu Tho Province). Natural regeneration of seedlings between the secondary natural
forests and nearby mixed species plantations were measured and compared. The dominant tree species consisted of Aporosa villosa, Ficus racemosa, Machilus bonii and Vernicia montan at the Hoa Binh site and Cinnamomum parthenoxylum, Ormosia balabsae and Lithocarpus gigantophyllus at the Phu Tho site, which are mostly pioneer species. The secondary natural forests had higher abundance and diversity indices
of seedlings than the mixed species plantations. Soil fertility of the secondary natural forests was better than that of the
mixed species plantations (P < 0.05). An important finding is that, for the study sites examined, secondary natural forest resulted in more diverse and
better-stocked forests than plantation forestry, implying that in areas where reforestation is undertaken the silvicultural
potential of natural regeneration should not be underestimated. 相似文献
312.
Min B. Rayamajhi Thai K. Van Paul D. Pratt Ted D. Center Phillip W. Tipping 《Plant Ecology》2007,192(1):119-132
Melaleuca quinquenervia (melaleuca) is a native of Australia but has become an invasive plant in Florida, USA. We conducted a long-term demographic
study of melaleuca in three sections (central, transitional, and peripheral) of monoculture stands located in Florida, and
quantified absolute density, diameter at breast height and basal area of trees by section at three sites. Additionally, we
monitored the impacts of natural enemy (insects and fungi) on melaleuca populations which became apparent after 2001. Both
absolute density and basal area, from before (1997–2001) and after noticeable natural-enemy impact (2002–2005), were compared.
Prior to the natural-enemy impact, absolute density of melaleuca trees declined primarily due to self-thinning and associated
losses of small trees, but diameter at breast height increased, as did the basal area. Later during the period when natural
enemies prevailed, absolute density declined at a significantly greater rate across all sections but was highest at the periphery.
The decrease in mean absolute density and basal area/ha of melaleuca during the natural-enemy impacted period coincided with
the increased incidence of the populations of plant-feeding insects and fungi. The mean diameter at breast height continued
to increase in all sections of the stands throughout the study period. An increasing trend in basal area prior to natural-enemy
impact was reversed after increase in natural-enemy abundance and noticeable impact in all three sections of the stands. These
findings lend support to a growing body of literature that implicates natural enemies as increasingly important density-independent
regulators of M. quinquenervia populations.
The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged 相似文献
313.
Jocelyn Quistrebert Marianna Orlova Gaspard Kerner Le Thi Ton Nguyìn Trong Luong Nguyìn Thanh Danh Quentin B. Vincent Fabienne Jabot-Hanin Yoann Seeleuthner Jacinta Bustamante Stphanie Boisson-Dupuis Nguyen Thu Huong Nguyen Ngoc Ba Jean-Laurent Casanova Christophe Delacourt Eileen G. Hoal Alexandre Alcaïs Vu Hong Thai Lai The Thnh Laurent Abel Erwin Schurr Aurlie Cobat 《PLoS genetics》2021,17(3)
314.
Kim Woojoo Pham Thai Hong Nguyen Phuong Dung Tran Anh Duc Ha Jungmoon Jablonski Piotr G. Lee Sang-im 《Journal of Ethology》2022,40(3):211-221
Journal of Ethology - Water strider (Gerridae) morphology and behavior have become the focus of interdisciplinary research in biological diversification and bio-inspired technology. However, the... 相似文献
315.
Preeyanan Anwised Thai Kabbua Theeranan Temsiripong Apisak Dhiravisit Sarawut Jitrapakdee Tomohiro Araki Kazunari Yoneda Sompong Thammasirirak 《The protein journal》2013,32(3):172-182
The first report of complete nucleotide sequences for α- and β-globin chains from the Siamese hemoglobin (Crocodylus siamensis) is given in this study. The cDNAs encoding α- and β-globins were cloned by RT-PCR using the degenerate primers and by the rapid amplification of cDNA ends method. The full-length α-globin cDNA contains an open reading frame of 423 nucleotides encoding 141 amino acid residues, whereas the β-globin cDNA contains an open reading frame of 438 nucleotides encoding 146 amino acid residues. The authenticity of both α- and β-globin cDNA clones were also confirmed by the heterologous expression in Escherichia coli (E. coli). This is the first time that the recombinant C. siamensis globins were produced in prokaryotic system. Additionally, the heme group was inserted into the recombinant proteins and purified heme-bound proteins were performed by affinity chromatography using Co2+-charged Talon resins. The heme-bound proteins appeared to have a maximum absorbance at 415 nm, indicated that the recombinant proteins bound to oxygen and formed active oxyhemoglobin (HbO2). The results indicated that recombinant C. siamensis globins were successfully expressed in prokaryotic system and possessed an activity as ligand binding protein. 相似文献
316.
Mussels can attach themselves to nearly all types of hard surfaces in wet environments. Such attractive adhesive ability of mussels is believed to rely on the amino acid composition of proteins found near the plaque–substrate interface. Dopamine (DA) is identified as a simplified mimic of mussel proteins, which are rich in 3,4‐dihydroxy‐l ‐phenylalanine and lysine, because it contains both catechol and amine functional groups. In this work, we have first applied this bioinspired adhesive to tackle a dye leaching problem of colorimetric oxygen indicator films, which are widely used to ensure the absence of oxygen inside the package of oxygen‐sensitive materials. Simple immersion of packaging films into a DA solution resulted in poly(DA) deposition, decreasing the water contact angle of the films from 105° to 65°. The poly(DA) coating could reduce the thionine leakage of the UV‐activated oxygen indicator film. The effects of poly(DA) coating were found to be dependent on the DA solution pH, the coating time, and the DA concentration. The film resistant to dye leaching lost its dye color by 5 min UVB irradiation and regained the color in the presence of oxygen, demonstrating that it functioned successfully as UV‐activated oxygen indicators. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 513–519, 2013 相似文献
317.
The largemouth bass cytochrome b gene 总被引:8,自引:0,他引:8
The cytochrome b gene is one of the protein-coding genes of the mitochondrial genome that has gained importance because of the ease with which molecular techniques can be applied to the analysis of its structure. The nucleotide sequence of the largemouth bass ( Microplerus salmoides ) cytochrome b gene was determined and the inferred amino acid structure is presented in the form of a structural model derived originally from rat cytochrome b . The inferred amino acid sequences from divergent animal species are aligned and compared in the context of this model. The data suggest that regions of the gene may be evolving at different rates due to different selection pressures associated with functional constraints. Conserved and variable regions of cytochrome b have been identified and can be targeted for species identification, the examination of intraspeciflc variation, and phylogenetic reconstructions in future research. 相似文献
318.
Background
The emerging field of integrative bioinformatics provides the tools to organize and systematically analyze vast amounts of highly diverse biological data and thus allows to gain a novel understanding of complex biological systems. The data warehouse DWARF applies integrative bioinformatics approaches to the analysis of large protein families. 相似文献319.
Dr. Lyle C. Dearden H. David Mosier Jr. Margo Brundage Christine Thai Regina Jansons 《Cell and tissue research》1986,246(2):401-412
Summary The effects of different doses of various steroids on growth, and on costal and epiphyseal chondrocytes, have been studied in prenatal, immature, and adult Long-Evans rats using histochemical techniques, and both light and electron microscopy. Both prenatal and postnatal treatments have been employed. The steroids used were cortisone (CA), betamethasome (BM), and, in the prenatal group only, dexamethasone (DM).Body weight is reduced in all treated rats (except the low dose of CA) by day 17 of gestation, with greater weight reductions occurring in rats receiving the higher dose level of each steroid. In rats treated prenatally or neonatally, and sacrificed postnatally on days 39–43 or days 116–127, body weights, and tibial and tail lengths, are less than in correspondingly aged controls, thus showing a persistence of the effects of treatment.Costal and epiphyseal cartilages in prenatal rats show cellular, synthetic, and ultrastructural alterations induced by treatment with glucocorticoids but the responses are not necessarily comparable. Except for the low dose of DM, the higher doses of each steroid are more effective in inhibiting, or altering, growth and cellular differentiation in the developing fetuses. Surprisingly, a low dose of DM has a more devastating effect on the cells and extracellular matrix of both costal and epiphyseal cartilage, than do higher dose-levels of the various steroids. Low doses of CA and BM are also effective in inhibiting or altering growth and cellular differentiation, but their effectiveness is largely limited to 17 days of gestation. The order of effect of the various doses of the different steroids on fetal cartilage, listed in decreasing order of severity, is as follows: 0.12 DM, 0.24 DM, 0.42 BM, 50 CA, with 25 CA and 0.18 BM being approximately equal and only slightly different from control cartilages. The effect of prenatal or neonatal glucocorticoid treatment on chondrocytes is minimal in the 30–43 day, or 116–127 day, postnatal groups. In immature and adult rats, cortisone affects the chondrocytes more deleteriously than does betamethasone, and a 5.0 mg dose of CA seems to affect chondrocytes, body weight, and tibial and tail lengths more than 0.2 or 7.5 mg doses.Supported in part by NIH grant HD 07074 and HD 12034 相似文献
320.