如何提高缉毒犬的实际工作能力

缉毒犬对各种毒品气味的分辨能力,即一头受训犬能够在各种复杂的环境中,准确地从烟、酒、食物、糖、茶、化妆品、药材以及化学物品等干扰气味中分辨出某种毒品气味,并反应正确。目前,有些地方的缉毒犬只是对单一毒品气味进行了训练：并且考虑在更为复杂的环境下的训练,即模拟训练。这种训练接近实战,要求带犬民警充分考虑到实战现场的复杂性,并以此为标准,对模拟训练中的三种形式进行合理的布局。     

喷头和施药液量对水稻植株上农药沉积和药剂防治效果的影响

为明确喷头及施药液量对水稻植株上农药沉积及药剂防治效果的影响,采用丽春红-G示踪法测定了4种喷头ST11001、ST11002、TR8001、TR8002在不同施药液量条件下喷雾农药在水稻植株上的沉积分布特性,并比较了4种喷头施用相同剂量的40%氯虫苯甲酰胺·噻虫嗪WDG对水稻纵卷叶螟Cnaphalocrocis medinalis和褐飞虱Nilaparvata lugens的防治效果。结果表明,选择ST11002和TR8001喷头,在施药液量300 L/hm~2条件下喷雾,单株水稻上的丽春红-G沉积量分别达到27.55μg和28.16μg;选择ST11001和TR8002喷头,在施药液量900 L/hm~2条件下喷雾,单株水稻上的丽春红-G沉积量仅分别为12.27μg和14.86μg。喷头和施药液量的改变不影响水稻植株上农药沉积分布特性,均为上层沉积量中层沉积量下层沉积量。当施药液量从300 L/hm~2增加到900 L/hm~2,4种喷头ST11001、ST11002、TR8001、TR8002喷雾在水稻基部的雾滴密度分别增加了8.21、8.54、7.79和9.69倍;但在相同施药液量下,4种喷头在水稻基部的雾滴密度没有显著差异。同一剂量下,喷头和施药液量不同组合的防治效果间差异显著。表明针对稻田不同防治对象,选择合适的喷头及施药液量将有助于提高农药沉积及防治效果。     

Relationship between zinc and zinc transporter expression in human lung cancer cells

AIM: To study the changes of zinc transporter gene expression in A-549 cell line exposed to ZnCl2 and N,N,N’,N’-tetrakis 2-pyridylmethyl ethylenediamine (TPEN).METHODS: Human lung cancer cell line A-549 was exposed to different concentrations of ZnCl2 (0, 50, 100, 150, 200 μmol/L) and TPEN (0, 5, 10, 15, 20 μmol/L), respectively. Twelve hours later, the cell viability was measured by MTT (methyl thiazolyl tetrazolium) and levels of zinc transporter mRNA was detected by RT-PCR. Zinquin was used to estimate the intracellular zinc concentrations.RESULTS: A-549 cell viability rate was significantly decreased when exposed to ZnCl2 at concentrations of 150 and 200 μmol/L, and to TPEN. The intracellular zinc concentration was significantly increased when exposed to ZnCl2 and decreased when exposed to TPEN. Zinc transporter (ZnT-1) mRNA level was increased along with the increase in the concentration of ZnCl2 but decreased when exposed to TPEN. The expressions of ZIP-1 and ZIP-10 (Zrt-and Irt-like protein) were increased along with the increase in the concentration of TPEN but decreased when exposed to ZnCl2.CONCLUSION: ZnT-1 expression is induced by zinc supplement. ZIP-1 and ZIP-10 expressions are induced by zinc deficiency and repressed by zinc supplement.     

Ascorbate levels and the activity of key enzymes in ascorbate biosynthesis and recycling in the leaves of 22 Chinese persimmon cultivars

The objective of this study was to determine diversities of ascorbic acid (AsA) and activities of enzymes involved in AsA metabolism, and to determine their relationships to AsA content in the leaves of Chinese persimmon (Diospyros kaki) cultivars. Results showed that there were huge differences not only in the contents of AsA and glutathione (GSH) but also in the enzyme activities of l-galactono-1,4-lactone dehydrogenase (GLDH, EC 1.3.2.3), dehydroascorbate reductase (DHAR, EC 1.8.5.1), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) in the leaves of 22 Chinese persimmon cultivars. Control of AsA levels mainly depended on the capacity for biosynthesis and GLDH activity played a main role in determining AsA levels in the leaves of persimmon. Both MDHAR and DHAR, MDHAR in particular, also played an important role in maintaining AsA redox state by reducing oxidized AsA back to AsA. But contents of GSH and hydrogen peroide (H₂O₂) and activity of APX were not significantly correlated with AsA content in the leaves of persimmon.     

Initiation and development of microspore embryogenesis in recalcitrant purple flowering stalk (Brassica campestris ssp. chinensis var. purpurea Hort.) genotypes

Purple flowering stalk (Brassica campestris ssp. chinensis var.purpurea Hort.) was generally regarded as a recalcitrant species for microspore culture in Brassica crops. Conditions for reliable induction of microspore embryogenesis were studied in 12 genotypes of purple flowering stalk. A treatment of short heat shock to microspore by incubating at 32 °C for 18 h was suitable for the survival of microspores, sustained cell divisions, and further induced embryogenesis. Subsequently, the reduced concentration of macro salts (1/2 NLN) provided an optimal condition for the development of embryoids. Under the optimized conditions for microspore embryoid development, 10 genotypes responded to microspore culture with the frequencies ranging from 2.7 to 70.5 embryoids per dish. However, regenerated plants were obtained from 9 genotypes, and more than 75% these regenerated plants were double haploid. This report establishes an efficient protocol for microspore culture and offers great potential for DH breeding in purple flowering stalk.     

猪流行性腹泻病毒云南省流行毒株S1基因序列分析

为深入了解云南省猪流行性腹泻病毒（porcine epidemic diarrhea virus,PEDV）的流行现状及现有疫苗株的保护效果,从2017—2022年云南省PEDV感染临床阳性样品中扩增出9份样品的PEDV S1基因,利用生物信息学方法,对9份样品S1基因进行了遗传进化树构建、同源性分析和氨基酸突变位点分析等。结果显示：2份样品位于G1基因群,其余7份位于G2基因群的G2b基因亚群。7份G2b基因亚群样品的核苷酸和推导氨基酸同源性较高,与G2基因群的AJ1102和L/W/L疫苗株处于不同基因亚群且同源性较低,并在第13、139、289和363位发生了不一致的突变位点;与现有疫苗株相比,在抗原中和位点COE区域以及其他区域,有明显的抗原性变化。结果表明：云南省存在G1基因群和G2b基因亚群PEDV同时流行,但以G2b基因亚群为主;流行株和疫苗株间存在较远的遗传和亲缘关系,以及氨基酸突变和抗原性差异,这很可能是导致目前PED控制不理想的原因,因此需要研发安全有效的疫苗。