Investigating amine derivatives of ambruticin VS-5 and VS-4

A structure-activity relationship around the amine group of the ambruticin VS series has been developed for antifungal activity. It was shown that the amine can be alkylated through reductive amination without loss of potency. However, if it is converted into either an amide, carbamate, or urea, a significant loss of potency is observed. Of the alkyl amines, small nonpolar groups are optimal for both potency and oral bioavailability. As a result of this study, one compound (KOS-2079) was taken into an animal efficacy model with success.     

The mildiomycin biosynthesis: initial steps for sequential generation of 5-hydroxymethylcytidine 5'-monophosphate and 5-hydroxymethylcytosine in Streptoverticillium rimofaciens ZJU5119

Mildiomycin (MIL) is a peptidyl nucleoside antibiotic with strong activity against powdery mildew disease of plants. We have cloned the MIL biosynthetic gene cluster in Streptoverticillum rimofaciens ZJU5119 and shown that this organism also produces the related antifungal compound, deshydroxymethyl mildiomycin (dHM-MIL). A cosmid genomic library was screened for a putative nucleotide hydrolase gene that is related to blsM from the blasticidin S cluster. Six cosmids were identified that contained a 3.5 kb DNA fragment that harbors a homologue of blsM. The sequence of the fragment revealed two open-reading frames that are likely to function in MIL formation: milA is a CMP hydroxymethylase gene and milB is the homologue of the CMP hydrolase gene blsM. Insertional disruption of milA abolished the production of MIL but not dHM-MIL, whereas a milB knockout strain did not produce either of the peptidyl nucleosides. Recombinant MilA was produced in E. coli and shown to specifically introduce a C-5 hydroxymethyl group on CMP, but it did not accept cytosine or dCMP as a substrate. MilB was also expressed and purified from E. coli and shown to efficiently hydrolyze both hydroxymethyl-CMP (HMCMP) and could accept CMP as an alternative substrate. The ratio of free HMC and cytosine released by MilB was ca. 9:1 in in vitro assays, and is consistent with the higher levels of MIL compared to dHM-MIL that are produced by Streptoverticillum rimofaciens.     

抗菌剂DCOIT及其改性发泡EVA的性能研究

以DCOIT（二氯辛基异噻唑啉酮）为防霉抗菌剂,EVA（乙烯/醋酸乙烯共聚物）为主要原料,制备抗菌发泡EVA材料;采用孢子萌发试验和自然集菌试验对DCOIT的防霉性能进行了研究;通过透射电镜观察DCOIT对细菌细胞形态的影响;同时进行了抗菌EVA试样的耐水持效防霉抗菌性能研究。结果表明,DCOIT对绳状青霉、球毛壳、黑曲霉、出芽短埂霉、大肠杆菌、金黄色葡萄球菌以及自然存在的多种菌均有显著的抑菌效果,具有一定的广谱防霉抗菌性;在DCOIT的作用下,大肠杆菌胞体形态发生了显著变化,细胞壁断裂,出现菌体空化现象;添加0.8%DCOIT的EVA试样具有优良的的耐水持效防霉抗菌性能。     

Development of Tolerance to the Dietary Plant Secondary Metabolite 1,8-cineole by the Brushtail Possum (<Emphasis Type="Italic">Trichosurus vulpecula</Emphasis>)

The common brushtail possum (Trichosurus vulpecula) is a generalist herbivore whose diet includes Eucalyptus leaves that are well defended by plant secondary metabolites (PSM) such as the terpene 1,8-cineole (cineole). We accustomed possums to a terpene-free diet, then challenged them with the addition of 2% cineole to the diet. Initially, there was a 50% reduction in total overnight food consumption associated with a marked decrease in the mass of the major feeding bout. After nine nights, however, cineole tolerance had developed as total food consumption had returned to the control amount. Compared to the control diet, the cineole diet was eaten in a larger number of smaller bouts, which were also eaten at a slower rate. The experiment was repeated with animals that had been accustomed to day-time feeding to take blood samples during feeding sessions. Feeding variables and blood concentration data for cineole were compared on the first and seventh day of the cineole diet. Although the total food consumed increased 2.5-fold after 7 days of the cineole diet, there was no increase in average blood cineole concentration, measured as the area under the concentration–time curve. This indicates that induction of liver enzymes resulted in greater pre-systemic metabolism of cineole and reduced bioavailability. The maximum tolerated blood concentration of cineole also increased, suggesting some adaptation of the central nervous system to the cineole aversive effects. This appears to be the first report in a vertebrate herbivore that consumption of a dietary PSM leads to metabolism induction and that this contributes to development of tolerance to the PSM. Overall, herbivores adapt to newly encountered dietary PSMs by immediate changes in feeding behavior followed by development of increased metabolism of PSM and probably diminished cellular responsiveness to effects.     

新形势下绿色皮革防霉剂的研究进展综述

介绍了目前所使用的皮革防霉剂的主要有效成分，综述了在环保、健康要求更加严格的新形势下绿色皮革防霉剂的研究进展及趋势。     

Performance and visceral tissue growth and development of Holstein calves fed differing milk replacer allowances and starch concentrations in pelleted starter

The objectives of this study were to investigate how milk replacer (MR) allowance and differing concentrations of starch and neutral detergent fiber in starter alters visceral tissue and overall growth of the calf. Calves were randomly assigned to 1 of 4 dietary treatments (n = 12 per treatment) arranged in a 2 × 2 factorial based on daily MR allowance (MRA) and amount of starch in pelleted starter (SPS) as follows: 0.691 kg of MR/d [dry matter (DM) basis] with starter containing low or high starch (12.0% and 35.6% starch, respectively) and 1.382 kg of MR/day (DM) with starter containing low or high starch. All calves were housed in individual pens with straw bedding until wk 5 when bedding was covered to minimize intake. Calves were fed MR twice daily (0700 and 1700 h) containing 24.5% crude protein (DM) and 19.8% fat (DM), and had access to pelleted starter (increased by 50 g/d if there were no refusals before weaning, and then 200 g/d during and after weaning) and water starting on d 1. Calves arrived between 1 and 3 d of age and were enrolled into an 8-wk study, with calves undergoing step-down weaning during wk 7. Intakes were measured daily, and body weight (BW) and blood samples were recorded and collected weekly. Calves were dissected in wk 8 for visceral tissue measurements. Overall, there was increased MR DM intake for the high- (0.90 ± 0.01 kg/d; ± SE) compared with the low-MRA (0.54 ± 0.01 kg/d) calves, whereas starter DM intake increased in low- (0.47 ± 0.05 kg/d) compared with high-MRA (0.20 ± 0.05 kg/d) calves, which was driven by increases in wk 6, 7, and 8. High-MRA calves had increased BW during wk 2, 3, 4, 5, 6, and 7. The difference in BW disappeared by wk 8, with overall average daily gain having a tendency to be increased in high (0.57 ± 0.04 kg/d) compared with low-MRA (0.50 ± 0.04 kg/d) calves, whereas average daily gain was increased in high-MRA calves during wk 2 and 3 and increased in low-MRA calves during wk 7 and 8. There were several differences throughout visceral tissue measurements, but most notably, an increase in rumen mass (i.e., full, empty, and digesta weights) in low- compared with high-MRA calves, as well as in low- compared with high-SPS calves was observed. The length, width, and 2-dimensional area of rumen papillae were also increased in low- (area: 0.88 ± 0.03 mm²) compared with high-MRA (0.46 ± 0.03 mm²) calves. The majority of differences were attributed to increased MR allowance, which contributed to reduced pelleted starter intake by more than 50% and reduced rumen development, whereas differences in starch intake from the completely pelleted starter had minimal effects on overall growth and tissue measurements.     

Comprehensive analysis of umami compounds by ion-pair liquid chromatography coupled to mass spectrometry

An ion-pair LC-ESI-MS method was developed capable of analyzing various reported umami or umami-enhancing compounds, including glutamic acid and 5'-ribonucleotides. The method was validated using tomato and potato samples and showed overall good analytical performance with respect to selectivity, detection limit, linearity, and repeatability. The method was applied to various tomato samples resulting in concentrations of glutamic acid and 5'-ribonucleotides that were in good comparison with literature. The methodology might also be used for the discovery of new umami (enhancing) compounds in an untargeted mode. This was to a certain extent demonstrated for tomato samples by correlating all peaks observed with the ion-pair liquid chromatography-mass spectrometry (LC-MS) method to sensory properties using multivariate statistics. PRACTICAL APPLICATION: This study describes the development and application of a LC-MS method, which can be used to quantify several known umami (enhancing) compounds in various foods. Furthermore, the method might be useful for the discovery of new umami (enhancing) compounds.     

直接竞争酶联免疫法测定呋喃妥因代谢物

目的建立动物组织中呋喃妥因代谢物1-氨基乙内酰脲的直接竞争酶联免疫(ELISA)检测法,为检测食品中呋喃妥因代谢物残留提供快速检测的方法。方法采用活化酯法制备辣根过氧化物酶标记抗原,并用棋盘法确定酶标抗原和抗体的稀释度,优化反应条件,建立检测呋喃妥因代谢物的直接竞争酶联免疫法,并对其进行方法学评价。结果该方法的线性方程为Y=-34.723X+158.01(r2=0.9922),线性检测范围为0.177~11.508ng/m L,IC50为1.291 ng/m L;猪肉、鸡肉、鱼肉的最低检测限分别为0.115、0.113、0.109μg/kg,加标回收率在82.6%~104.7%之间,批内变异系数在3.6%~9.3%之间,批间变异系数在4.3%~12.4%之间。结论本方法快速准确,适用于动物组织中呋喃妥因代谢物的检测。     

Evaluation of the systemic innate immune response and metabolic alterations of nonlactating cows with diet-induced subacute ruminal acidosis

Subacute ruminal acidosis (SARA) increases lipopolysaccharide endotoxin in the rumen, which might translocate into the systemic circulation, triggering a cascade of clinical and immunological alterations. The objective of this study was to characterize the clinical immune and metabolic responses to ruminal-derived lipopolysaccharide in nonlactating cows induced with SARA using 2 challenges, a grain-based SARA challenge (GBSC) or an alfalfa-pellet SARA challenge (APSC). Six dry, nonlactating Holstein cows were used in a 3 × 3 Latin square arrangement of treatments with 4-wk experimental cycles. All cows received the control diet containing 70% forage and 30% mixed concentrates (dry matter basis) for 3 wk. In wk 4, cows received a control diet, GBSC (38% wheat-barley pellets, 32% other mixed concentrate, and 30% forages), or APSC (45% mixed concentrate, 32% alfalfa pellets, and 23% other forages). Total plasma proteins and immunology-related proteins, acute phase proteins, blood cells, serum chemistry, mRNA gene expression of peripheral blood cell surface markers, and selected proinflammatory cytokines were evaluated. Ruminal pH was lower in both groups with induced SARA compared with a control group. Ruminal endotoxins were higher in GBSC; however, plasma endotoxin was not detected in any study group. No significant differences in feed intake, rectal temperature, white blood cell counts, or differentials were found between control and SARA challenge groups; changes in glucose, urea, Ca, and Mg were observed in SARA groups. Total plasma proteins were lower in both SARA groups, and acute phase proteins were higher in GBSC. The expression of CD14, MD2, and TLR4 mRNA in peripheral blood leukocytes was not affected by SARA induction. The induction of SARA as a result of GBSC or APSC challenge was successful; however, LPS was not detected in plasma. Changes in clinical, metabolic, and inflammatory responses were not observed in the SARA-challenged cows, suggesting that, in this study, SARA was not associated with a systemic response to inflammation.     

基于非靶向代谢组学技术的氨基脲胁迫雌性栉孔扇贝的毒性作用机制研究

目的 本研究基于非靶向代谢组学技术,分析了暴露于50 mg.L^-1氨基脲72 h的雌性栉孔扇贝性腺代谢物组成及含量变化,以探究氨基脲对雌性栉孔扇贝性腺组织毒性及其作用机制。结果 非靶向代谢组学结果表明：与对照组相比,在氨基脲胁迫下,雌性栉孔扇贝性腺组织代谢物发生改变,共有64种差异表达代谢物,其中上调33个,下调31个;在HMDB数据库中进行比对分析,注释到36个差异表达代谢物,主要功能分类为有机酸及其衍生物、脂类和类脂分子及有机氮化合物等。差异代谢物功能通路的富集结果表明：氨基酸代谢、脂质代谢、信号转导、核苷酸代谢和内分泌系统等生物过程受到显著影响。根据筛选出的差异代谢物的生理功能及其涉及的代谢通路分析,差异代谢物鸟氨酸上调,推断雌性栉孔扇贝通过增加鸟氨酸含量,维持其正常生长过程。推测氨基脲可能通过影响栉孔扇贝的AMPKα-2 mRNA表达,进而影响了核苷酸代谢通路和类脂肪代谢作用通路,使得栉孔扇贝体内软脂酸含量下降。氨基脲可能通过对NMDAR的拮抗作用以及对GAD(谷氨酸脱羧酶)的抑制,干扰神经信号传导,导致雌性栉孔扇贝相关行为异常。结论 本研究探究了氨基脲对雌性栉孔扇贝性腺组织毒性作用及栉孔扇贝的响应调控机制,为后期深入研究氨基脲毒性作用机制提供理论依据。