Effects of Forest Regrowth and Urbanization on Ecosystem Carbon Storage in a Rural–Urban Gradient in the Southeastern United States

Forest regrowth after cropland abandonment and urban sprawl are two counteracting processes that have influenced carbon (C) sequestration in the southeastern United States in recent decades. In this study, we examined patterns of land-use/land-cover change and their effect on ecosystem C storage in three west Georgia counties (Muscogee, Harris, and Meriwether) that form a rural–urban gradient. Using time series Landsat imagery data including MSS for 1974, TM for 1983 and 1991, and ETM for 2002, we estimate that from 1974 to 2002, urban land use in the area has increased more than 380% (that is, 184 km²). Most newly urbanized land (63%) has been converted from forestland. Conversely, cropland and pasture area has decreased by over 59% (that is, 380 km²). Most of the cropland area was converted to forest. As a result, the net change in forest area was small over the past 29 years. Based on Landsat imagery and agricultural census records, we reconstructed an annual gridded data set of land-cover change for the three counties for the period 1850 to 2002. These data sets were then used as input to the Terrestrial Ecosystem Model (TEM) to simulate land-use effects on C fluxes and storage for the study area. Simulated results suggest that C uptake by forest regrowth (approximately 23.0 g C m⁻² y⁻¹) was slightly greater than the amount of C released due to deforestation (approximately 18.4 g C m⁻² y⁻¹), thus making the three counties a weak C sink. However, the relative importance of different deforestation processes in this area changed significantly through time. Although agricultural deforestation was generally the most important C-release process, the amount of C release attributable to urbanization has increased over time. Since 1990, urbanization has accounted for 29% of total C loss from the study area. We conclude that balancing urban development and forest protection is critically important for C management and policy making in the southeastern United States.     

Sustained expression in mammalian cells with DNA complexed with chitosan nanoparticles

This work investigates the preparation and in vitro efficiency of chitosan gene transfection systems. Chitosan was used to prepare nanoparticles with a size range of 40-200 nm as determined using photon correlation spectroscopy (PCS) and 40-80 nm as determined using transmission electron microscopy (TEM). The ability of particles to complex DNA was investigated using gel retardation. Plasmid DNA pGL3-Control encoding firefly luciferase and pCH110 encoding beta-galactosidase were used as reporter genes. For transfection 293 human embryonal kidney cells and Chinese hamster ovary (CHO-K1) cells were used. The expression of luciferase was assayed and expressed as relative light units per milligram of protein (RLU/mg protein). Results showed that these chitosan particles have potential as vectors for the transfer of DNA into mammalian cells. Cellular transfection by the chitosan-pGL3-Control particles showed a sustained expression of the luciferase gene for about 10 days. Commercial transfection reagents, SuperFect and Lipofectin were also used. In contrast to chitosan particles, the duration of expression for both SuperFect and Lipofectin was only about 2 days. Agarose gel electrophoresis and displacement experiments using polyaspartic acid indicated a probable multiple interaction between DNA and chitosan whilst the interaction between DNA and the polyamidoamine dendrimer appears to be only ionic interaction. No toxic effect on the mammalian cells was seen with chitosan. SuperFect and Lipofectin however, were observed to engender marked cytotoxicity. Poly-D,L-lactide (PLA) nanoparticles (40-80 nm) and poly-L-lactide (PLLA) lamellae (2-6 microm) were also used to load DNA by an adsorption procedure, but these failed to give good expression data.     

平茬对岩黄芪属植物生物学性状的影响

探讨了3种岩黄芪属植物平茬与未平茬植株的生物学性状.结果表明,平茬后3种岩黄芪属植物植株的多种性状与未平茬植株无显著差异,但平茬植株基部新生枝条数比未平茬植株增加1.91倍.平茬不仅复壮了植株个体,提高了产量,而且提高了家畜可食部分（叶+嫩茎）的比例.平茬岩黄芪属植株5～8月生物量中以叶和嫩茎为主,在9月,由于枝条木质化,家畜不可食部分迅速增加,平均不可食部分占总生物量的69.26％.而未平茬的岩黄芪属植株由于有上一年残留的枯死枝条,因而5～8月一直有老茎存在,9月份家畜不可食部分平均达到77.79％.岩黄芪属植物可在植物生长的第2年进行平茬,应在8月底以前进行收割.8月平茬处理3种岩黄芪灌丛的叶面积指数高于对照,散射光系数低于对照,说明在8月平茬处理植株的生长高于对照植株,生长更为繁茂.     

Caffeine Junkie: an Unprecedented Glutathione S-Transferase-Dependent Oxygenase Required for Caffeine Degradation by Pseudomonas putida CBB5

Caffeine and other N-methylated xanthines are natural products found in many foods, beverages, and pharmaceuticals. Therefore, it is not surprising that bacteria have evolved to live on caffeine as a sole carbon and nitrogen source. The caffeine degradation pathway of Pseudomonas putida CBB5 utilizes an unprecedented glutathione-S-transferase-dependent Rieske oxygenase for demethylation of 7-methylxanthine to xanthine, the final step in caffeine N-demethylation. The gene coding this function is unusual, in that the iron-sulfur and non-heme iron domains that compose the normally functional Rieske oxygenase (RO) are encoded by separate proteins. The non-heme iron domain is located in the monooxygenase, ndmC, while the Rieske [2Fe-2S] domain is fused to the RO reductase gene, ndmD. This fusion, however, does not interfere with the interaction of the reductase with N₁- and N₃-demethylase RO oxygenases, which are involved in the initial reactions of caffeine degradation. We demonstrate that the N₇-demethylation reaction absolutely requires a unique, tightly bound protein complex composed of NdmC, NdmD, and NdmE, a novel glutathione-S-transferase (GST). NdmE is proposed to function as a noncatalytic subunit that serves a structural role in the complexation of the oxygenase (NdmC) and Rieske domains (NdmD). Genome analyses found this gene organization of a split RO and GST gene cluster to occur more broadly, implying a larger function for RO-GST protein partners.     

A modified cornish pasty method for ex ovo culture of the chick embryo development

Chick embryos grown in ex ovo culture by the modified Cornish pasty method reported in Nagai, Lin and Sheng in this issue.     

Chemical Composition and Antioxidant Activity of Essential Oil of Chinese Propolis

The chemical composition and in vitro antioxidant activity of the essential oil of propolis (EOP) collected from 25 locations in China was investigated. Steam‐distillation extraction was used to extract the EOP, and chemical composition was identified by GC/MS. The antioxidant activities of EOP were also measured. The result showed that a total of 406 compounds were detected in EOP. The major compounds of Chinese EOP were cedrol, γ‐eudesmol, benzyl alcohol, phenethyl alcohol, 2‐methoxy‐4‐vinylphenol, 3,4‐dimethoxystyrene and guaiol. Principal component analysis revealed the significant correlation between EOP compositions and their origins, and certain correlation was detected between EOP and their color. Linear discriminant analysis showed that 88 % and 84 % of the propolis samples were predicted correctly as the groupings identified by climatic zone and the color, respectively. Furthermore, the differences of antioxidant activities of EOP were significant. EOP of Shandong had the strongest antioxidant activities, whereas EOP of Guangdong, Yunnan and Hunan showed the poorest.     

Design,Expression, Purification and Characterization of the Recombinant Immunotoxin 4D5 scFv-TRAIL

International Journal of Peptide Research and Therapeutics - Immunotoxins are chimeric proteins that combine antibodies and toxins in targeted cancer therapy. Despite the promising application...     

Dracorhodin perchlorate inhibits osteoclastogenesis through repressing RANKL-stimulated NFATc1 activity

Osteolytic skeletal disorders are caused by an imbalance in the osteoclast and osteoblast function. Suppressing the differentiation and resorptive function of osteoclast is a key strategy for treating osteolytic diseases. Dracorhodin perchlorate (D.P), an active component from dragon blood resin, has been used for facilitating wound healing and anti-cancer treatments. In this study, we determined the effect of D.P on osteoclast differentiation and function. We have found that D.P inhibited RANKL-induced osteoclast formation and resorbed pits of hydroxyapatite-coated plate in a dose-dependent manner. D.P also disrupted the formation of intact actin-rich podosome structures in mature osteoclasts and inhibited osteoclast-specific gene and protein expressions. Further, D.P was able to suppress RANKL-activated JNK, NF-κB and Ca²⁺ signalling pathways and reduces the expression level of NFATc1 as well as the nucleus translocation of NFATc1. Overall, these results indicated a potential therapeutic effect of D.P on osteoclast-related conditions.     

Identification of novel susceptibility loci for non‐syndromic cleft lip with or without cleft palate

Although several genome‐wide association studies (GWAS) of non‐syndromic cleft lip with or without cleft palate (NSCL/P) have been reported, more novel association signals are remained to be exploited. Here, we performed an in‐depth analysis of our previously published Chinese GWAS cohort study with replication in an extra dbGaP case‐parent trios and another in‐house Nanjing cohort, and finally identified five novel significant association signals (rs11119445: 3’ of SERTAD4, P = 6.44 × 10⁻¹⁴; rs227227 and rs12561877: intron of SYT14, P = 5.02 × 10⁻¹³ and 2.80 × 10⁻¹¹, respectively; rs643118: intron of TRAF3IP3, P = 4.45 × 10⁻⁶; rs2095293: intron of NR6A1, P = 2.98 × 10⁻⁵). The mean (standard deviation) of the weighted genetic risk score (wGRS) from these SNPs was 1.83 (0.65) for NSCL/P cases and 1.58 (0.68) for controls, respectively (P = 2.67 × 10⁻¹⁶). Rs643118 was identified as a shared susceptible factor of NSCL/P among Asians and Europeans, while rs227227 may contribute to the risk of NSCL/P as well as NSCPO. In addition, sertad4 knockdown zebrafish models resulted in down‐regulation of sox2 and caused oedema around the heart and mandibular deficiency, compared with control embryos. Taken together, this study has improved our understanding of the genetic susceptibility to NSCL/P and provided further clues to its aetiology in the Chinese population.