Effect of Erosion on Productivity in Subtropical Red Soil Hilly Region: A Multi-Scale Spatio-Temporal Study by Simulated Rainfall

The effects of water erosion (including long-term historical erosion and single erosion event) on soil properties and productivity in different farming systems were investigated. A typical sloping cropland with homogeneous soil properties was designed in 2009 and then protected from other external disturbances except natural water erosion. In 2012, this cropland was divided in three equally sized blocks. Three treatments were performed on these blocks with different simulated rainfall intensities and farming methods: (1) high rainfall intensity (1.5 - 1.7 mm min⁻¹), no-tillage operation; (2) low rainfall intensity (0.5 - 0.7 mm min⁻¹), no-tillage operation; and (3) low rainfall intensity, tillage operation. All of the blocks were divided in five equally sized subplots along the slope to characterize the three-year effects of historical erosion quantitatively. Redundancy analysis showed that the effects of long-term historical erosion significantly caused most of the variations in soil productivity in no-tillage and low rainfall erosion intensity systems. The intensities of the simulated rainfall did not exhibit significant effects on soil productivity in no-tillage systems. By contrast, different farming operations induced a statistical difference in soil productivity at the same single erosion intensity. Soil organic carbon (SOC) was the major limiting variable that influenced soil productivity. Most explanations of long-term historical erosion for the variation in soil productivity arose from its sharing with SOC. SOC, total nitrogen, and total phosphorus were found as the regressors of soil productivity because of tillage operation. In general, this study provided strong evidence that single erosion event could also impose significant constraints on soil productivity by integrating with tillage operation, although single erosion is not the dominant effect relative to the long-term historical erosion. Our study demonstrated that an effective management of organic carbon pool should be the preferred option to maintain soil productivity in subtropical red soil hilly region.     

A First Generation Comparative Chromosome Map between Guinea Pig (Cavia porcellus) and Humans

The domesticated guinea pig, Cavia porcellus (Hystricomorpha, Rodentia), is an important laboratory species and a model for a number of human diseases. Nevertheless, genomic tools for this species are lacking; even its karyotype is poorly characterized. The guinea pig belongs to Hystricomorpha, a widespread and important group of rodents; so far the chromosomes of guinea pigs have not been compared with that of other hystricomorph species or with any other mammals. We generated full sets of chromosome-specific painting probes for the guinea pig by flow sorting and microdissection, and for the first time, mapped the chromosomal homologies between guinea pig and human by reciprocal chromosome painting. Our data demonstrate that the guinea pig karyotype has undergone extensive rearrangements: 78 synteny-conserved human autosomal segments were delimited in the guinea pig genome. The high rate of genome evolution in the guinea pig may explain why the HSA7/16 and HSA16/19 associations presumed ancestral for eutherians and the three syntenic associations (HSA1/10, 3/19, and 9/11) considered ancestral for rodents were not found in C. porcellus. The comparative chromosome map presented here is a starting point for further development of physical and genetic maps of the guinea pig as well as an aid for genome assembly assignment to specific chromosomes. Furthermore, the comparative mapping will allow a transfer of gene map data from other species. The probes developed here provide a genomic toolkit, which will make the guinea pig a key species to unravel the evolutionary biology of the Hystricomorph rodents.     

Oseltamivir Population Pharmacokinetics in the Ferret: Model Application for Pharmacokinetic/Pharmacodynamic Study Design

The ferret is a suitable small animal model for preclinical evaluation of efficacy of antiviral drugs against various influenza strains, including highly pathogenic H5N1 viruses. Rigorous pharmacokinetics/pharmacodynamics (PK/PD) assessment of ferret data has not been conducted, perhaps due to insufficient information on oseltamivir PK. Here, based on PK data from several studies on both uninfected and influenza-infected groups (i.e., with influenza A viruses of H5N1 and H3N2 subtypes and an influenza B virus) and several types of anesthesia we developed a population PK model for the active compound oseltamivir carboxylate (OC) in the ferret. The ferret OC population PK model incorporated delayed first-order input, two-compartment distribution, and first-order elimination to successfully describe OC PK. Influenza infection did not affect model parameters, but anesthesia did. The conclusion that OC PK was not influenced by influenza infection must be viewed with caution because the influenza infections in the studies included here resulted in mild clinical symptoms in terms of temperature, body weight, and activity scores. Monte Carlo simulations were used to determine that administration of a 5.08 mg/kg dose of oseltamivir phosphate to ferret every 12 h for 5 days results in the same median OC area under the plasma concentration-time curve 0–12 h (i.e., 3220 mg h/mL) as that observed in humans during steady state at the approved dose of 75 mg twice daily for 5 days. Modeling indicated that PK variability for OC in the ferret model is high, and can be affected by anesthesia. Therefore, for proper interpretation of PK/PD data, sparse PK sampling to allow the OC PK determination in individual animals is important. Another consideration in appropriate design of PK/PD studies is achieving an influenza infection with pronounced clinical symptoms and efficient virus replication, which will allow adequate evaluation of drug effects.     

Factors influencing <Emphasis Type="Italic">in vitro</Emphasis> regeneration from protoplasts of wild cotton (<Emphasis Type="Italic">G. klotzschianum</Emphasis> A) and RAPD analysis of regenerated plantlets

Plants of a diploid wild cotton species (G. klotzschianum A.) were efficiently regenerated from protoplasts isolated from immature somatic embryos and suspension cultures by studying various factors affecting regeneration. Purified protoplasts were cultured with the density of 2–10×10⁵ ml⁻¹, and the medium was k₃ inorganic salts with modified KM₈P organic compositions, supplemented with several combinations of PGRs. Calluses were formed from protoplasts of suspension cultures and immature somatic embryos. The influences of carbon sources and GA₃ on callus differentiation and somatic embryo germination were analyzed. Somatic embryos germinated normally and formed regenerated plantlets. Regenerated plantlets were transferred to the soil and seeds were obtained. Random amplified polymorphic DNA (RAPD) analysis using 80 arbitrary oligonucleotide 10-mers showed 23 primers that gave 74 clear reproducible bands, with amplification products being monomorphic for 14 tested plantlets. A total of 1036 bands obtained exhibited no aberration in RAPD banding patterns in the 14 plants. Plants regenerated via somatic embryogenesis from the diploid cotton protoplasts have genetic homogeneity.     

Saccharification of orange peel wastes with crude enzymes from new isolated <Emphasis Type="Italic">Aspergillus japonicus</Emphasis> PJ01

This study investigated the saccharification of orange peel wastes with crude enzymes from Aspergillus japonicus PJ01. Pretreated orange peel powder was hydrolyzed by submerged fermentation (SmF) and solid-state fermentation (SSF) crude enzymes, the results showed that 4 % (w/v) of solid loading, undiluted crude enzymes, and 45 °C were suitable saccharification conditions. The hydrolysis kinetics showed that the apparent Michaelis–Menten constant \(K_{{\text{m}_{app} }}\) and maximal reaction rate \(V_{{\max_{app} }}\) were 73.32 g/L and 0.118 g/(L min) for SmF enzyme, and 41.45 g/L and 0.116 g/(L min) for SSF enzyme, respectively. After 48 h of hydrolysis, the saccharification yields were 58.5 and 78.7 %, the reducing sugar concentrations were 14.9 and 20.1 mg/mL by SmF and SSF enzymes. Material balance showed that the SmF enzymatic hydrolysate was enriched galacturonic acid > arabinose > galactose > xylose, and the SSF enzymatic hydrolysate was enriched galacturonic acid > xylose > galactose > arabinose.     

正常足月儿畸变产物耳声发射(DPOAEs)特性分析

研究提出正常足月儿畸变产物耳声发射（ＤＰＯＡＥｓ） 特性分析如下：１ ． ＤＰＯＡＥｓ 反应强度曲线,ＤＰ 图显示两个反应峰（ｆ２ ＝ １ ．６ 和５ ．０ ｋＨｚ） 和一个反应谷（ｆ２ ＝ ３ ．１ ～４ ．０ ｋＨｚ） ;２． ＤＰＯＡＥ 本底噪声及其特性,ｆ２ ＝ １．０ ｋＨｚ 其测试频率点（２ｆ１ －ｆ２） 本底噪声最高（Ｐ＜ ０ ．０５） ,ｆ２ ＝ ３ ．１ ,４．０ 和５ ．０ｋＨｚ ,测试频率点（２ｆ１ －ｆ２） 本底噪声较低（Ｐ＜ ０．０５） ;除ｆ２ ＝ ４．０ ｋＨｚ 外,ＤＰＯＡＥ 本底噪声与其反应强度均未呈现直线相关特性;３ ． ＤＰＯＡＥ ＳＮＲ 特性,ｆ２ ＝ １．０ ｋＨｚ 其ＳＮＲ 最小（Ｐ＝ ０．０００） ,ｆ２ ＝２ ．０ ｋＨｚ 其ＳＮＲ 最大（Ｐ０ ．００３） ;４． ＤＰＯＡＥ ＳＮＲ 和ＴＥＯＡＥ ＳＮＲ 相关特性,除１．０ ｋＨｚ 频段外,其余频段其二者间均有着非常显著的直线相关特性。     

Parallel Evolution of Polydactyly Traits in Chinese and European Chickens

Polydactyly is one of the most common hereditary congenital limb malformations in chickens and other vertebrates. The zone of polarizing activity regulatory sequence (ZRS) is critical for the development of polydactyly. The causative mutation of polydactyly in the Silkie chicken has been mapped to the ZRS; however, the causative mutations of other chicken breeds are yet to be established. To understand whether the same mutation decides the polydactyly phenotype in other chicken breeds, we detected the single-nucleotide polymorphism in 26 different chicken breeds, specifically, 24 Chinese indigenous breeds and 2 European breeds. The mutation was found to have fully penetrated chickens with polydactyly in China, indicating that it is causative for polydactyly in Chinese indigenous chickens. In comparison, the mutation showed no association with polydactyly in Houdan chickens, which originate from France, Europe. Based on the different morphology of polydactyly in Chinese and European breeds, we assumed that the trait might be attributable to different genetic foundations. Therefore, we subsequently performed genome-wide association analysis (GWAS) to locate the region associated with polydactyly. As a result, a ~0.39 Mb genomic region on GGA2p was identified. The region contains six candidate genes, with the causative mutation found in Chinese indigenous breeds also being located in this region. Our results demonstrate that polydactyly in chickens from China and Europe is caused by two independent mutation events that are closely located in the chicken genome.