Marine myxobacteria as a source of antibiotics--comparison of physiology, polyketide-type genes and antibiotic production of three new isolates of Enhygromyxa salina

Three myxobacterial strains, designated SWB004, SWB005 and SWB006, were obtained from beach sand samples from the Pacific Ocean and the North Sea. The strains were cultivated in salt water containing media and subjected to studies to determine their taxonomic status, the presence of genes for the biosynthesis of polyketides and antibiotic production. 16S rDNA sequence analysis revealed the type strain Enhygromyxa salina SHK-1(T) as their closest homolog, displaying between 98% (SWB005) and 99% (SWB004 and SWB006) sequence similarity. All isolates were rod-shaped cells showing gliding motility and fruiting body formation as is known for myxobacteria. They required NaCl for growth, with an optimum concentration of around 2% [w/v]. The G + C-content of genomic DNA ranged from 63.0 to 67.3 mol%. Further, the strains were analyzed for their potential to produce polyketide-type structures. PCR amplified ketosynthase-like gene fragments from all three isolates enhances the assumption that these bacteria produce polyketides. SWB005 was shown to produce metabolites with prominent antibacterial activity, including activity towards methicillin resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE).     

野生卷丹百合黄酮类化合物抗氧化能力的研究

以野生卷丹百合、兰州百合为材料,测定D-101大孔树脂纯化处理前后的总黄酮含量,并比较卷丹百合、芦丁和兰州百合的抗氧化能力。结果表明,用D-101大孔树脂纯化处理前后卷丹百合中总黄酮含量分别为2.187 9和1.723 4 mg/g,兰州百合在纯化前后总黄酮含量分别为1.650 6和1.326 3 mg/g。卷丹百合总黄酮对O2-.、.OH和DPPH都有良好的清除能力且清除效果强于芦丁及兰州百合,表现为:①当提取物质量浓度达到4.00 g/L时,对O2-.的清除率达到89.64%,比同质量浓度芦丁与兰州百合分别高出70.58%和2.57%;②当提取物质量浓度达到2.40 g/L时,对.OH的清除率为62.83%,而同质量浓度芦丁与兰州百合分别为35.68%和25.35%;③当提取物质量浓度达到1.00 g/L时,对DPPH的清除率为47.45%,在同质量浓度下分别比芦丁与兰州百合高出6.82和7.39个百分点。     

Effects of dietary additives (potassium diformate/organic acids) as well as influences of grinding intensity (coarse/fine) of diets for weaned piglets experimentally infected with Salmonella Derby or Escherichia coli

The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed‐withholding‐period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6‐mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4–5 h after a further oral application of ～10⁹–10¹⁰ CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.     

Role of social structure in establishment of an invasive large mammal after translocation

Background

Data on the movement behavior of translocated wild pigs is needed to develop appropriate response strategies for containing and eliminating new source populations following translocation events. We conducted experimental trials to compare the home range establishment and space-use metrics, including the number of days and distance traveled before becoming range residents, for wild pigs translocated with their social group and individually.

Results

We found wild pigs translocated with their social group made less extensive movements away from the release location and established a stable home range ~5 days faster than those translocated individually. We also examined how habitat quality impacted the home range sizes of translocated wild pigs and found wild pigs maintained larger ranges in areas with higher proportion of low-quality habitat.

Conclusion

Collectively, our findings suggest translocations of invasive wild pigs have a greater probability of establishing a viable population near the release site when habitat quality is high and when released with members of their social unit compared to individuals moved independent of their social group or to low-quality habitat. However, all wild pigs translocated in our study made extensive movements from their release location, highlighting the potential for single translocation events of either individuals or groups to have far-reaching consequences within a much broader landscape beyond the location where they are released. These results highlight the challenges associated with containing populations in areas where illegal introduction of wild pigs occurs, and the need for rapid response once releases are identified. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

施肥对不同时期遮阴小麦光合、产量和品质的影响

为探究通过施肥能否减缓太阳辐射减弱对小麦生长发育及产量形成的不利影响,通过田间模拟试验,研究了不同生育期遮阴下施肥对冬小麦植株光合生理、产量和品质的影响。采用3因素3水平正交试验设计,遮阴设3水平,即不遮阴(S0,遮阴率0)、开花-成熟期遮阴(S1,平均遮阴率68%)、分蘖-成熟期遮阴(S2,平均遮阴率68%);复合肥(N-P₂O₅-K₂O)施用量设3水平,即100 kg·hm^-2(F1)、200 kg·hm^-2(F2)和300 kg·hm^-2(F3);硅肥施用量(以SiO₂计)设3水平,即0(R0)、200 kg·hm^-2(R1)和400 kg·hm^-2(R2)。结果表明：S1提高冬小麦开花-灌浆期旗叶净光合速率(Pn),S1和S2降低开花-灌浆期气孔导度(Gs)和灌浆期蒸腾速率(Tr),提高胞间CO₂浓度(Ci);S1和S2降低千粒质量、结实率、产量,减少籽粒直链淀...     

Dual Chamber Pacemaker Implantation in Dogs with Atrioventricular Block

Background: Pacemaker implantation is the treatment of choice for symptomatic bradyarrhythmias. In dogs, a single chamber system is commonly used. In human patients with high-grade 2nd- or 3rd-degree atrioventricular (AV) block, physiologic pacing is recommended, because it improves cardiac output, blood pressure, exercise tolerance, and quality of life. In dogs, this type of pacing is seldom used.
Hypothesis: The implantation of a dual chamber pacemaker in dogs with AV block is a feasible procedure for restoring AV synchrony.
Animals: Thirty-three privately owned dogs with high-grade 2nd- or 3rd-degree AV block were included.
Methods: Patient data of all dogs with AV block presented for pacemaker implantation between December 1997 and November 2004 were reviewed.
Results: Dual chamber pacemaker implantation with AV synchronous stimulation was successfully performed in 33/33 dogs (100%). In 9/33 (27%) major and in 12/33 (36%) minor complications were observed. Mean survival time for the patients discharged from hospital (n = 32) was 33.6 ± 20.4 months (range, 3.9–83.5 months).
Conclusion and Clinical Importance: Dual chamber pacing is a feasible procedure in dogs with 2nd- or 3rd-degree AV block and is not associated with a higher complication rate compared with single chamber pacemaker systems. A major advantage over ventricular demand pacemaker systems is the restoration of AV synchrony for a substantial period of time.     

Analysis of pharmaceutical dosage forms for oxfendazole: I. Reverse phase liquid chromatographic determination of oxfendazole in swine premix

A reverse phase liquid chromatographic (LC) procedure is described for quantitating oxfendazole (2-(methoxycarbonylamino)-5-phenylsulfinylbenzimidazole] in swine premix. Sample preparation consists of extracting oxfendazole with an acetone-methanol mixture. An aliquot of the extract is then centrifuged to separate undissolved premix excipients. Internal standard is added to the supernate and the sample is further diluted with water-acetonitrile-phosphoric acid (80 + 20 + 1). Oxfendazole is quantitatively determined using a Partisil-5-ODS-3 column with acetonitrile-0.01 M phosphate buffer (pH 6.0) as the mobile phase. The method is stability specific and yields a mean recovery of 101.1 +/- 0.4% for the 1.35% premix formulation. The dependence of chromatographic performance characteristics on mobile phase organic content, pH, and buffer concentration is also reported.     

遏蓝菜硒蛋白的纯化、结构表征及抗氧化活性研究

为探究遏蓝菜硒蛋白的结构特征及抗氧化活性,采用超声辅助酶提法和DEAE-Sepharose FF阴离子交换柱层析法,从遏蓝菜中提取、分离和纯化出两种硒蛋白组分(PSP-2和PSP-3),运用光谱法和扫描电镜等方法对其结构进行表征,并检测其体外抗氧化活性.结果表明:PSP-2和PSP-3各含有15种氨基酸,包括6种必需氨...     

AFLP analysis of genetic diversity in leafy kale (<Emphasis Type="Italic">Brassica oleracea</Emphasis> L. convar. <Emphasis Type="Italic">acephala</Emphasis> (DC.) Alef.) landraces,cultivars and wild populations in Europe

AFLP markers were used to characterize diversity and asses the genetic structure among 17 accessions of kale landraces, cultivars and wild populations from Europe. The range of average gene diversity in accessions was 0.11–0.27. Several landraces showed higher levels of diversity than the wild populations and one cultivar had the lowest diversity measures. The landraces that were most genetically diverse were from areas where kales are known to be extensively grown, suggesting in situ conservation in these areas as a supplement to storage of seeds in gene banks. An analysis of molecular variance (AMOVA) showed that 62% of the total variation was found within accessions. For most accessions, genetic distance was not related to geographic distance. Similarities among accessions were probably not caused by recent gene flow since they were widely separated geographically; more likely the relationship among them is due to seed dispersal through human interactions. Our results indicate that a kale population found in a natural habitat in Denmark was probably not truly wild but most likely an escape from a cultivated Danish kale that had subsequently become naturalized.     

村庄规划中自然地理要素的制约及改善村庄人居环境建议

现阶段我国村庄规划向多规合一的方向转变,其定位转变为:整合村土地利用规划、村庄建设规划等乡村规划,实现土地利用规划、城乡规划等有机融合,编制“多规合一”的实用性村庄规划。因此,在这新形势下,综合考虑各方面自然地理要素对村庄规划的影响以实现对村庄人居环境的改善是发展的必然要求。