Genetic Diversity and Molecular Evolution of Chinese Waxy Maize Germplasm

Waxy maize (Zea mays L. var. certaina Kulesh), with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima’s D and Fu and Li’s F*) were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection.     

Reconstitution of cellulose and lignin after [C2mim][OAc] pretreatment and its relation to enzymatic hydrolysis

Although the effects of cellulose crystallinity and lignin content as two major structural features on enzymatic hydrolysis have been extensively studied, debates regarding their effects still exist. In this study, reconstitution of cellulose and lignin after 1‐ethyl‐3‐methylimidazolium acetate ([C₂mim][OAc]) pretreatment was proposed as a new method to study their effects on enzymatic digestibility. Different mechanisms of lignin content for reduction of cellulose hydrolysis were found between the proposed method and the traditional method (mixing of cellulose and lignin). The results indicated that a slight change of the crystallinity of the reconstituted materials may play a minor role in the change of enzyme efficiency. In addition, the present study suggested that the lignin content does not significantly affect the digestibility of cellulose, whereas the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase plays an important role when an ionic liquid pretreatment of biomass was conducted. Biotechnol. Bioeng. 2013; 110: 729–736. © 2012 Wiley Periodicals, Inc.     

Effect of Zinc Source on Performance, Zinc Status, Immune Response, and Rumen Fermentation of Lactating Cows

Two experiments were conducted to examine the effect of zinc (Zn) source on the performance, Zn status, immune response, and rumen fermentation of lactating cows to find the most available Zn source for dairy production. In Experiment 1, a total of 30 multiparous Holstein cows were randomly allocated by body weight and milk yield to one of five treatments in a completely randomized design. Cows were fed a total mixed ration (TMR) with no Zn addition (containing 37.60 mg?Zn/kg TMR by analysis), and the basal TMR supplemented with 40 mg?Zn/kg TMR from either Zn sulfate or one of three organic Zn chelates with weak (Zn-AA W), moderate (Zn-Pro M), or strong (Zn-Pro S) chelation strengths, respectively for 55 days. In Experiment 2, the in vitro rumen fermentation method was used in a completely randomized design involving a 4?×?3 factorial arrangement of treatments. The four Zn sources were the same as those used in Experiment 1, and the three supplemental Zn levels in the rumen fluid were 0, 10, and 20 μg/mL, respectively. The feed intake, milk composition, and somatic cell count (SCC) were unaffected (P?>?0.05) by treatments. However, the milk yield was increased (P?<?0.05) by addition of Zn from both the Zn-AA W and Zn-Pro S. Plasma Zn level at the end of the experiment was increased (P?<?0.05) by addition of Zn from all three organic sources. Serum antibody titers on day 21 after vaccination with foot and mouth disease (FMD) vaccine were increased (P?<?0.05) by both supplemental Zn-AA W and Zn-Pro S. The organic Zn sources with different chelation strengths supplemented at the added Zn level of 10 μg/mL were more effective (P?<?0.05) in improving the rumen fermentation than Zn sulfate, with the most effective being Zn-AA W. In conclusion, Zn source had no influence on the feed intake, milk composition, and SCC; however, both the Zn-AA W and Zn-Pro S were more effective than Zn-Pro M and Zn sulfate in enhancing the rumen fermentation, Zn status, and humoral immune response as well as improving milk yield of lactating cows. The improved milk production might be attributed to the improved rumen fermentation, Zn status, and immune function.     

Rapamycin decreases tau phosphorylation at Ser214 through regulation of cAMP-dependent kinase

Preventing or reducing tau hyperphosphorylation is considered to be a therapeutic strategy in the treatment of Alzheimer’s disease (AD). Rapamycin may be a potential therapeutic agent for AD, because the rapamycin-induced autophagy may enhance the clearance of the hyperphosphorylated tau. However, recent rodent studies show that the protective effect of rapamycin may not be limited in the autophagic clearance of the hyperphosphorylated tau. Because some tau-related kinases are targets of the mammalian target of rapamycin (mTOR), we assume that rapamycin may regulate tau phosphorylation by regulating these kinases. Our results showed that in human neuroblastoma SH-SY5Y cells, treatment with rapamycin induced phosphorylation of the type IIα regulatory (RIIα) subunit of cAMP-dependent kinase (PKA). Rapamycin also induced nuclear translocation of the catalytic subunits (Cat) of PKA and decreases in tau phosphorylation at Ser214 (pS214). The above effects of rapamycin were prevented by pretreatment with the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor U0126. In addition, these effects of rapamycin might not depend on the level of tau expression, because similar results were obtained in both the non-tau-expressing wild type human embryonic kidney 293 (HEK293) cells and HEK293 cells stably transfected with the longest isoform of recombinant human tau (tau441; HEK293/tau441). These findings suggest that rapamycin decreases pS214 via regulation of PKA. Because tau phosphorylation at Ser214 may prime tau for further phosphorylation by other kinases, our findings provide a novel possible mechanism by which rapamycin reduces or prevents tau hyperphosphorylation.     

北京地区急性呼吸道感染儿童中人鼻病毒感染状况研究

为了解北京地区急性呼吸道感染儿童中人鼻病毒(HRV)-A、B、C型(尤其是HRV-C)的感染状况及分子生物学特征,本研究收集了2011年1月至12月急性呼吸道感染患儿呼吸道标本703例,采用半巢式PCR方法同时进行HRV-A、B、C检测,并对HRV阳性标本进行VP4/VP2衣壳蛋白编码区基因序列测定及进化树分析。结果显示703例标本中共有54例HRV检测阳性,总阳性检出率为7.7%(54/703);HRV感染的儿童中年龄在5岁以下的占94.4%(51/54);HRV检出率在毛细支气管炎患儿中最高(23.1%),其次是哮喘(20.0%)、肺炎(11.0%)、急性支气管炎(4.3%)、急性上呼吸道感染(4.1%)患儿;序列分析表明54例HRV检测阳性标本中25例为HRV-A(46.3%,25/54),8例为HRV-B(14.8%,8/54),21例为HRV-C(38.9%,21/54);HRV同一基因型内各核苷酸序列同源性为70.0%～100.0%,不同基因型间核苷酸序列同源性为55.5%～65.8%。上述结果提示,HRV是引起北京地区儿童急性呼吸道感染(尤其是下呼吸道感染)重要的病毒病原之一;HRV-C阳性检出率与HRV-A相近,较HRV-B高;HRV各个基因型间具有较高变异性。     

Asia1型口蹄疫病毒受体结合位点多样性

摘要：【目的】产甘油假丝酵母作为一株优良高产甘油菌株,已成功应用于工业生产15年。近年来由于产甘油假丝酵母染色体倍性尚不明确,限制了对其进行遗传改造的研究进展,因而我们对产甘油假丝酵母染色体倍性研究,分析确定其染色体倍性。【方法】选用酿酒酵母细胞进行生孢,制备酿酒酵母单倍体细胞作对照,并选用热带假丝酵母作为二倍体酵母细胞对照,利用血球计数板得到热带假丝酵母、产甘油假丝酵母、单倍体及二倍体酿酒酵母细胞数,提取染色体,通过二苯胺检测法测定DNA含量。由于在相同紫外照射条件下单倍体细胞比二倍体细胞更容易死亡,因     

Effect of Different Levels of Copper and Molybdenum Supplements on Performance,Nutrient Digestibility,and Follicle Characteristics in Cashmere Goats

A 2 × 3 factorial arrangement of treatments was used to investigate the effects of different levels of copper (Cu, 0, 19, and 38 mg/kg, dry matter (DM)) and molybdenum (Mo, 0 and 5 mg/kg, DM) supplements and an interaction of these two factors on growth performance, nutrient digestibility, and cashmere and follicle characteristics in cashmere goats. Thirty-six Liaoning cashmere goats (approximately 1.5 years of age; 27.53 ± 1.38 kg of body weight) were assigned randomly to one of six treatments and fed with Chinese wildrye- and alfalfa hay-based treatment diets (the basal diet contained 4.72 mg Cu/kg, 1.65 mg Mo/kg, and 0.21% S.). Body weight was measured on two consecutive days at the start and the end of the 70-day experimental period. On day 30, the metabolism trial was conducted to study the effects of dietary Cu and Mo on nutrient digestibility. The cashmere and skin samples were collected on day 70. Copper supplementation increased (P < 0.05) growth performance and fiber digestion, but there were no differences (P > 0.05) between Cu-supplemented groups. Addition of 19 mg Cu/kg DM increased (P < 0.05) cashmere growth length or growth rate by increasing the number of active secondary follicles. Molybdenum supplementation decreased (P < 0.05) growth, but did not affect (P > 0.05) nutrient digestion, cashmere, and follicle characteristics. There is a tendency or significant interaction effect of Cu and Mo on growth performance (P = 0.057), cashmere growth (P = 0.076), or diameter (P < 0.05) which might be accomplished by changing the number of secondary follicle and active secondary follicle, and secondary to primary follicle ratio. In conclusion, the optimal supplemental Cu level for Liaoning cashmere goats fed with the basal diet was 19 mg/kg DM (the total dietary Cu level of 23.72 mg/kg DM), while 38 mg Cu/kg DM supplementation was found to be needed when 5 mg Mo/kg was added in the basal diet during the cashmere growing period.     

Structural comparison and enhanced enzymatic hydrolysis of the cellulosic preparation from Populus tomentosa Carr., by different cellulose-soluble solvent systems

This study aims to establish an efficient pretreatment process using cellulose-dissolution solvents to enhance the enzymatic saccharification. LiOH/urea, LiCl/DMAc, concentrated phosphoric acid, ionic liquid (1-butyl-3-methylimidazolium chloride; [BMIM]Cl) and N-methyl-morpholine-N-oxide (NMMO) were selected as the cellulose dissolution agents. Except the cellulosic sample regenerated from LiCl/DMAc system, all the other treated samples exhibited lower cellulose crystallinity and degree of polymerization (DP), and consequently, exhibited a significant enhancement on enzymatic hydrolysis kinetic. Ionic liquid pretreatment offered unique advantages in the hydrolysis rate in the first 10 h, probably due to the extensively structural transformation of cellulose from the crystalline to the amorphous region. Meanwhile, the regenerated cellulose from concentrated phosphoric acid almost completely consisted of cellulose II, and achieved the highest saccharification yield.     

不同西甜瓜品种对截形叶螨生长发育和繁殖的影响

[目的]明确不同西甜瓜品种对截形叶螨Tetranychus truncates Ehara生长发育及繁殖的影响,为西甜瓜品种布局和该虫的综合治理提供科学依据.[方法]在实验室条件下,研究截形叶螨在不同西甜瓜品种(西瓜早佳8424、西瓜美都、西瓜嘉美和甜瓜金玉红2号、甜瓜玉菇)上的发育历期、产卵量和生命表参数.[结果]截形叶螨在西瓜早佳8424和甜瓜玉菇上的存活率较高,分别为95.00％和86.55％,而在西瓜美都和甜瓜金玉红2号上存活率较低,只有75.38％和70.45％;截形叶螨在不同西甜瓜品种上的繁殖力也存在显著差异,在西瓜早佳8424和西瓜美都上的繁殖适合性最高,即抗虫性最弱,产卵期长且产卵量大,如在西瓜早佳8424上平均单雌产卵量达(35.31±5.35)粒,而在西瓜嘉美上的繁殖适合性最低,即抗虫较最强,产卵期短产卵量少,平均单雌产卵量为(19.96±2.02)粒;此外,西瓜美都和西瓜早佳8424的内禀增长率rm和周限增长率λ最高,分别为0.203 1、0.161 7和1.225 2、1.175 5;西瓜嘉美的净增值率R0最低,仅为16.7.[结论]在供试的5个西甜瓜品种中,西瓜早佳8424和美都是最适宜截形叶螨生长和繁殖的品种,而西瓜嘉美有较高的抗虫性.     

Insignificant Medium-Term Vitamin D Status Change after 25-Hydroxyvitamin D Testing in a Large Managed Care Population

Objectives

To examine the clinical utility of 25-hydroxyvitamin D (25(OH)D) testing in achieving medium-term vitamin D (VD) sufficiency in a managed care population.

Methods

Retrospective study of a continuously-enrolled patient population in a 3-year period between 2011 and 2013. Primary outcome was VD status at ∼1 year after 25(OH)D testing. Patient demographics, comorbidities, medications, and 25(OH)D test results were gathered from relevant databases and multivariate logistic regression analysis used to study the risk factors of persistent VD deficiency or insufficiency.

Results

Of 22,784 patients, 7533 (females 69.3%) did 14,563 25(OH)D tests, with an estimated cost of $582,520. Of the 7533 patients, 1126 had another 25(OH)D test at 300–400 days after the first one. Based on the two test results, 234 patients (20.8%) maintained sufficient 25(OH)D levels; 132 (11.7%) turned from VD-sufficient into VD-insufficient or -deficient; 538 (47.8%) remained VD-insufficient or -deficient, and only 222 (19.7%) improved to be VD-sufficient. Overall, only 8.0% more patients were VD-sufficient at ∼1 year after 25(OH)D testing. Only younger age and higher BMI were independent risk factors for persistent low 25(OH)D levels and high-dose VD use was not associated with achieving VD sufficiency.

Conclusions

25(OH)D testing only benefits a small portion of patients thus lacks clinical utility in achieving VD sufficiency in the medium term but incurs a significant cost. A practical strategy to treat VD deficiency or insufficiency is needed; without it, 25(OH)D testing adds little value to most patients’ health and should be used with discretion.