Control of bacterial and fungal biofilms by natural products of Ziziphus joazeiro Mart. (Rhamnaceae)

The aim of this study is to verify the action of the aqueous leaf extract Ziziphus joazeiro in the eradication of bacterial and fungal biofilms, and to compare these effects with the stem bark extracts, as well as with conventional standard drugs. The presence of secondary metabolites was observed through phytochemical prospection assays. The effect of the aqueous extract on microbial biofilm formation was observed by OD600 nm absorbance and the crystal violet assay. For bacterial and fungal biofilms, chlorhexidine gluconate and fluconazole, respectively, were used as positive controls. Phytochemical characterization showed the presence of secondary metabolite classes common to both extracts such as flavonoids, steroids and saponins. In particular, in the aqueous leaf extract phenols, condensed tannins and alkaloids were observed. Eradication results using the aqueous leaf extract showed an inhibition of the microbial biofilm mass, moreover the biofilms were more sensitive to the bark extract, which presented a greater inhibition number and an action similar to standard drugs. It is important to highlight the leaf extract showed significant eradication at the lowest concentrations for mature yeast biofilms, thus demonstrating its potential to modify microbial resistance susceptibility. Bacterial and fungal biofilm eradication results using the Ziziphus joazeiro aqueous extracts presented a biofilm inhibition effect for both, moreover the results support the ethnopharmacological knowledge surrounding the use of Ziziphus joazeiro stems in the community. In comparison, the bark extract presented a more effective treatment than the leaf extract against biofilms, presenting inhibition levels similar to the used standard drugs.     

锌、锰、铁和铜离子对水稻幼苗生长及SOD活性的影响

用一定浓度的Zn^2 、Mn^2 、Fe^2 和Cu^2 溶液培养水稻幼苗，对水稻幼苗生长及生理活性物质的影响进行研究。结果表明：用MnSO4溶液培养的幼苗新生叶全部枯黄，叶片相对较短，根系生长受到抑制。用ZnSO4、CuSO4溶液培养的幼苗，叶呈黄绿色，苗株矮小，根系衰退。用FeSO4溶液培养的幼苗，叶呈深绿色，苗株长势旺盛。根系长势良好，Mn^2 使水稻超氧化物歧化酶（SOD）活性明显减弱，Cu^2 、Fe^2 使水稻SOD活性明显增强，Zn^2 对水稻SOD活性无明显影响，不同金属离子浓度处理对水稻酯酶活性无明显影响。     

过氧化氢及硫酸亚铁诱导洋葱表皮细胞凋亡

[目的]探讨过氧化氢与硫酸亚铁对洋葱表皮细胞凋亡的影响。[方法]分别设置4组处理：处理①：2 ml蒸馏水（对照组）;处理②：1 ml蒸馏水＋1 ml 4 mmol/LFeSO4;处理③：1 ml蒸馏水＋1 ml 2 mmol/LH2O2;处理④：1 ml 2 mmol/LH2O2＋1 ml 4 mmol/LFeSO4,处理洋葱表皮细胞24 h后,观察其凋亡情况。[结果]处理①的细胞正常;处理②的细胞与对照组相似;处理③的细胞处于明显凋亡状态;处理④的细胞未出现明显凋亡。[结论]FeSO4对洋葱表皮细胞凋亡有抑制作用。     

Stability constant of Fe2+ chelates with soluble ligands from incubated soils

Summary The stability constants (log K) of Fe²⁺ chelates were determined on the basis of the shift in peak potential during the reduction of Fe²⁺ by a consortium of soluble ligands from incubated soils. Log K values ranged from 2.6 to 4.5. On average a change in pH of 1 unit induced a change in log K of 0.92 units. Aeration of the anaerobic decomposition products increased log K. The log K for Fe²⁺ chelates was about 0.8 units larger than that for Mn²⁺ chelates. It is considered that the chelation of ferrous iron plays an important role in the mobility and availability of iron to plants.     

Physiological adaptive indicators in fasted neonate broiler chicks in response to calcium gluconate injection

Four hundred and eighty mixed‐sex broiler chicks aged 3 h after hatching were allotted according to a completely random design in a 6 × 2 × 2 factorial schedule into two groups of 12 replications of 20 chicks each. The main experimental factors were fasting for 0, 6, 12, 24, 36 and 48 h after chick placement and calcium gluconate (Ca‐glu) injection (0 and 0.6 ml). Live body weight (BW) of chicks decreased linearly (Y = 43.36–0.109BW_0 h, r² = 0.876) as neonatal fasting extended. Injection of 0.6 ml Ca‐glu at 3 h post‐hatching did not affect weight loss of chicks. Yolk residuals (YR) utilized linearly (Y = 5.75–0.062YR, r² = 0.956) by 0.062 g/h in neonate fasted chicks up to 48 h, showing no effect of Ca‐glu injection. Neonatal fasting periods longer than 12 h increased liver weight (p < 0.05). The mean absolute and proportional (% of BW_0 h) breast and leg weight were reduced linearly as neonatal fasting extended (p < 0.05). Serum glucose concentration increased up to 6 h and then reduced linearly to 150 mg/dl after 48‐h fasting. The Ca‐glu treatment influenced serum glucose level for a short period up to 6 h of fasting. Serum Ca concentration sharply increased up to threefolds in the birds received Ca‐glu injection resulting in acute hypercalcemia, then decreased to the initial level after 24‐h feed withdrawal (p < 0.05). The mean serum level for creatinine, uric acid, cholesterol, HDL, albumins and total proteins significantly increased during the fasting periods of 6 to 48 h and significantly elevated in the birds receiving 0.6‐ml Ca‐glu injection compared with the non‐treated chicks (p < 0.05). It was concluded that subcutaneous administration of 0.6 ml Ca‐glu in the chick's neck did not suitably support the increased metabolic demands for glucose and calcium in feed‐deprived neonate chicks.     

Zinc gluconate and zinc sulphate as dietary zinc sources for Atlantic salmon

Different chemical forms of essential minerals and trace elements supplemented to feed may show different bioavailability in fish. The present experiment was performed to compare an organic zinc form (Zn-gluconate) with zinc sulphate as dietary zinc sources for Atlantic salmon. Triplicate groups of fish were fed commercial fish meal based diets supplemented with either a low zinc level (50 mg Zn kg⁻¹) or medium zinc level (180 mg Zn kg⁻¹) as zinc gluconate or zinc sulphate for 6 months. Growth, mortality and feed conversion were recorded through the experiment. Fish were sampled initially and every month for zinc status analyses measured as whole-body zinc concentration. After 4 and 6 months, vertebral zinc concentration was measured and serum zinc was analysed at the end of the experiment. There were no differences in growth or mortality during the experiment. The results showed a significant effect of dietary zinc supplementation level on zinc status in fish for both zinc forms. However, there were no differences in zinc status between groups given different zinc forms. In conclusion, the present experiment showed that zinc sulphate and zinc gluconate are equally efficient as zinc supplements in salmon feeds within the concentrations normally found in salmon feed.     

硫化亚铁阻燃剂的研究

[目的]研制硫化亚铁阻燃剂。[方法]由阻燃试剂和表面活性剂组成硫化亚铁阻燃剂,用于农药中间体生产过程使用的加氢催化剂的回收。采用DSC/TGA热分析仪考察其阻燃效果。[结果]结果表明,该方法具有操作简单、样品用量少、结果准确等优点。在温度为39～45℃环境下做对比试验,结果显示,未处理催化剂最高温度达76℃,此时经自制阻燃剂处理过的催化剂温度比其低33℃,比进口阻燃剂TP006处理的催化剂略低,表明未处理催化剂阻燃效果良好。[结论]该研究结果为阻燃剂的更进一步研究提供科学依据。     

与Fe(Ⅲ)共存的Fe(Ⅱ)分光光度法测定

Fe(Ⅱ)的含量及变化与土壤和沉积物的氧化还原性质关系密切.当与Fe(Ⅲ)共存时,Fe(Ⅱ)的测定往往受到干扰.本文研究了常用显色剂2,2’-联吡啶和菲洛嗪(Ferrozine)测定土壤Fe(Ⅱ)时存在的问题及解决办法.结果表明,Fe(Ⅲ)可与显色剂作用形成络合物,该络含物对Fe(Ⅱ)测定所用波段的光线具有吸收作用,从而使Fe(Ⅱ)浓度被过高估计.Fe(Ⅲ)对Fe(Ⅱ)测定的干扰程度与其浓度及所选显色剂有关.当以2,2’-联吡啶为显色剂时,单位浓度Fe(Ⅲ) (1.0 mg/L)将导致Fe(Ⅱ)的测定值比实际值高0.012 mg/L;而当菲洛嗪为显色剂时,单位浓度Fe(Ⅲ)引起的Fe(Ⅱ)高估值在0.010～0.032 mg/L之间.F-能够抑制Fe(Ⅲ)-显色剂络合物的形成.当F-的加入量超过Fe(Ⅲ)的4倍时,F-能有效地消除Fe(Ⅲ)的干扰.实际样品的测定结果表明,改进的Fe(Ⅱ)分光光度法能够满足土壤及沉积物中Fe(Ⅱ)的准确测定.     

甘氨酸亚铁的合成和晶体结构研究

以甘氨酸和七水硫酸亚铁为原料合成了甘氨酸亚铁。采用溶剂挥发法得到了晶体,并通过红外谱图和X-射线单晶衍射确定了晶体的结构。化合物属于三斜晶系,空间群P-1,晶胞参数:a=0.59949(3)nm,b=0.67626(4)nm,c=1.33192(6)nm,α=85.453(4)°,β=82.914(4)°,γ=83.115(5)°,V=0.53085(5)nm3,C4H30N2O22Fe2S2,Mr=634.12,Z=1,R1=0.0219,wR2=0.0640[I>2σ(I)],S=1.005。化合物中铁(Ⅱ)配位数为6,配位多面体为变形的八面方体构型。结构式为 。     

葡萄糖酸铬对锦鲤生长、部分血液生化指标及肝胰脏抗氧化指标的影响

为研究饲料中葡萄糖酸铬添加量对锦鲤Cyprinus carpio生长、部分血液生化指标和抗氧化指标的影响,选取体质量为(4.18"0.38)g的锦鲤进行为期8周的饲养试验,试验鱼共525尾,随机分成7组,每组设3个平行,分别投喂添加不同含量葡萄糖酸铬的试验饲料,其中Cr3+含量分别为0、0.1、0.2、0.4、0.8、1.6、3.2 mg/kg(饲料)。结果表明:在葡萄糖酸铬添加量为0.4 mg/kg时,锦鲤增重率(BWG)、特定生长率(SGR)和蛋白质效率(PER)显著升高(P0.05),饲料系数(FCR)显著降低(P0.05);添加葡萄糖酸铬能显著提高锦鲤血清中总蛋白(TP)含量(P0.05),血糖(GLU)含量在葡萄糖酸铬添加量为0.4~1.6 mg/kg时显著降低(P0.05),甘油三酯(TG)、总胆固醇(TC)含量在葡萄糖酸铬添加量为0~0.4 mg/kg时无显著性差异(P0.05),添加量超过0.8 mg/kg时TG和TC含量显著高于对照组(P0.05);锦鲤肝胰脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化氢酶(GSH-PX)活力均随葡萄糖酸铬添加含量的升高呈先升高后降低的趋势,最高值分别出现在0.4、0.8、1.6 mg/kg葡萄糖酸铬添加组且显著高于其他组(P0.05),丙二醛(MDA)含量在葡萄糖酸铬添加量超过0.4 mg/kg时显著升高(P0.05)。研究表明,在饲料中添加葡萄糖酸铬能促进锦鲤生长,降低血糖含量,提高肝胰脏抗氧化能力,以增重率为指标,根据折线模型得出锦鲤饲料中最适Cr3+含量为0.24 mg/kg(饲料)。