Sex-specifically responsive strategies to phosphorus availability combined with different soil nitrogen forms in dioecious Populus cathayana

雌雄青杨不同氮形态下性别差异性的磷利用策略 磷的吸收和利用效率对植物生长和产量尤为重要。然而,在不同氮形态下,雌雄异株植物对土壤磷的吸收和利用策略尚不清楚。本论文研究了雌雄青杨(Populus cathayana)在低氮、硝态氮和铵态氮下对 土壤磷的吸收和利用策略。研究结果表明,在较高的土壤供磷条件下,青杨雌株在两种氮形态下较雄株而言,均具有较高的生物量、根长密度、比根长和地上磷含量。此外,在正常供磷条件下,与硝态氮相比,青杨雌株在铵态氮的供应下具有更长的根系、更大的根长密度和比根长,而具有较少的根尖数。相比而言,在低磷条件下,青杨雄株在两种氮形态下均具有较小的根系、较大的叶片光合磷的利用效率以及较高的磷的再转运潜力。而且,青杨雌株在硝态氮条件下与铵态氮相比,具有较高的应对低磷潜力。在低磷条件下,铵态氮下青杨雄株叶片磷的光合利用效率和叶片磷再转运潜力明显高于硝态氮。这些结果表明,在正常供磷条件下,青杨雌株较雄株而言,具有更强的磷吸收能力及较高的生物量,尤其在硝态氮条件下;相比而言,青杨雄株在两种氮形态下较雌株而言,具有更有效的磷的利用效率,从而具有较高的对磷缺乏的忍耐能力。     

Medium pH, carbon and nitrogen concentrations modulate the phosphate solubilization efficiency of Penicillium purpurogenum through organic acid production

Aims: To study phosphate solubilization in Penicillium purpurogenum as function of medium pH, and carbon and nitrogen concentrations. Methods and Results: Tricalcium phosphate (CP) solubilization efficiency of P. purpurogenum was evaluated at acid or alkaline pH using different C and N sources. Glucose‐ and (NH₄)₂SO₄‐based media showed the highest P solubilization values followed by fructose. P. purpurogenum solubilizing ability was higher in cultures grown at pH 6·5 than cultures at pH 8·5. Organic acids were detected in both alkaline and neutral media, but the relative percentages of each organic acid differed. Highest P release coincided with the highest organic acids production peak, especially gluconic acid. When P. purpurogenum grew in alkaline media, the nature and concentration of organic acids changed at different N and C concentrations. A factorial categorical experimental design showed that the highest P‐solubilizing activity, coinciding with the highest organic acid production, corresponded to the highest C concentration and lowest N concentration. Conclusions: The results described in the present study show that medium pH and carbon and nitrogen concentrations modulate the P solubilization efficiency of P. purpurogenum through the production of organic acids and particularly that of gluconic acid. In the P solubilization optimization studies, glucose and (NH₄)₂SO₄ as C and N sources allowed a higher solubilization efficiency at high pH. Significance and Impact of the Study: This organism is a potentially proficient soil inoculant, especially in P‐poor alkaline soils where other P solubilizers fail to release soluble P. Further work is necessary to elucidate whether these results can be extrapolated to natural soil ecosystems, where different pH values are present. Penicillium purpurogenum could be used to develop a bioprocess for the manufacture of phosphatic fertilizer with phosphate calcium minerals.     

水稻永绿色基因超表达和突变对其叶片氮碳代谢若干指标的影响

通过水培实验,研究了水稻永绿色(Stay-green rice,SGR)基因超表达和突变对叶片氮碳代谢的影响。结果表明,在正常生长条件下,SGR基因超表达降低了水稻叶片可溶性蛋白、叶绿素及淀粉的含量,但可溶性糖和游离氨基酸含量增加,并提高了谷氨酰胺合成酶(GS)活性和谷氨酸合成酶(GOGAT)活性;SGR基因突变增加了水稻叶片淀粉和可溶性蛋白质含量,并提高了硝酸还原酶(NR)活性。在缺氮条件下,SGR基因超表达与野生型叶片各生理指标的变化趋势一致,但是SGR基因突变体叶片中淀粉含量的变化趋势与野生型及SGR基因超表达的不一致。这说明SGR蛋白水平的变化在一定程度上影响了水稻叶片的氮碳代谢。     

胃肠宁对利血平所致大鼠脾虚模型的影响

目的 观察胃肠宁对大鼠脾虚证模型的影响.方法 36只大鼠随机分为正常对照组、脾虚模型组、四君子汤组和胃肠宁组,每组9只.采用利血平复制大鼠脾虚模型,连续灌胃14 d后,处死大鼠,分离肝、十二指肠和血清,测定各组大鼠血浆LDH、AKP、AchE、CK和肝组织匀浆中SOD、MDA、GSH-Px、NOS含量变化,并观察各组大...     

中成药序贯疗法治疗肾虚血瘀型月经过少84例疗效观察

目的：观察中成药补肾益脑丸、经舒颗粒序贯疗法治疗肾虚血瘀型月经过少84例的临床疗效。方法：采用中成药序贯疗法按照月经周期（经后期、经间期、经前期、月经期）治疗本病,经后期服用补肾益脑丸,经间期服用补肾益脑丸和经舒颗粒,经前期、月经期服用经舒颗粒,3个月为一疗程。结果：共治疗84例,总有效率92.8%。结论：本方法对肾虚血瘀型月经过少具有补肾益精、养血调经的功效。     

AGC1‐malate aspartate shuttle activity is critical for dopamine handling in the nigrostriatal pathway

The mitochondrial transporter of aspartate‐glutamate Aralar/AGC1 is a regulatory component of the malate‐aspartate shuttle. Aralar deficiency in mouse and human causes a shutdown of brain shuttle activity and global cerebral hypomyelination. A lack of neurofilament‐labeled processes is detected in the cerebral cortex, but whether different types of neurons are differentially affected by Aralar deficiency is still unknown. We have now found that Aralar‐knockout (Aralar‐KO) post‐natal mice show hyperactivity, anxiety‐like behavior, and hyperreactivity with a decrease of dopamine (DA) in terminal‐rich regions. The striatum is the brain region most affected in terms of size, amino acid and monoamine content. We find a decline in vesicular monoamine transporter‐2 (VMAT2) levels associated with increased DA metabolism through MAO activity (DOPAC/DA ratio) in Aralar‐KO striatum. However, no decrease in DA or in the number of nigral tyrosine hydroxylase‐positive cells was detected in Aralar‐KO brainstem. Adult Aralar‐hemizygous mice presented also increased DOPAC/DA ratio in striatum and enhanced sensitivity to amphetamine. Our results suggest that Aralar deficiency causes a fall in GSH/GSSG ratio and VMAT2 in striatum that might be related to a failure to produce mitochondrial NADH and to an increase of reactive oxygen species (ROS) in the cytosol. The results indicate that the nigrostriatal dopaminergic system is a target of Aralar deficiency.     

Gastric intrinsic factor deficiency with combined GIF heterozygous mutations and FUT2 secretor variant

Several genome-wide association studies (GWAS) have identified a strong association between serum vitamin B12 and fucosyltransferase 2 (FUT2), a gene associated with susceptibility to Helicobacter pylori infection. Hazra et al. conducted a meta-analysis of three GWAS and found three additional loci in MUT, CUBN and TCN1. Other GWAS conducted in Italy and China confirmed the association for FUT2 gene. Alpha-2-fucosyltransferase (FUT2) catalyzes fucose addition to form H-type antigens in exocrine secretions. FUT2 non-secretor variant produces no secretion of H-type antigens and is associated with high-plasma vitamin B12 levels. This association was explained by the influence of FUT2 on H. pylori, which is a risk factor of gastritis, a main cause of vitamin B12 impaired absorption. However, we recently showed that H. pylori serology had no influence on FUT2 association with vitamin B12, in a large sample population, suggesting the involvement of an alternative mechanism. GIF is another gene associated with plasma levels of vitamin B12 and gastric intrinsic factor (GIF) is a fucosylated protein needed for B12 absorption. Inherited GIF deficiency produces B12 deficiency unrelated with gastritis. We report 2 families with heterozygous GIF mutation, 290T>C, M97T, with decreased binding affinity of GIF for vitamin B12 and one family with heterozygous GIF mutation 435_437delGAA, K145_N146delinsN and no B12 binding activity of mutated GIF. All cases with vitamin B12 deficit carried the FUT2 rs601338 secretor variant. Ulex europeus binding to GIF was influenced by FUT2 genotypes and GIF concentration was lower, in gastric juice from control subjects with the secretor genotype. GIF290C allele was reported in 5 European cases and no Africans among 1282 ambulatory subjects and was associated with low plasma vitamin B12 and anaemia in the single case bearing the FUT2 secretor variant. We concluded that FUT2 secretor variant worsens B12 status in cases with heterozygous GIF mutations by impairing GIF secretion, independently from H. pylori-related gastritis.     

The impact of oxidative stress in thiamine deficiency: A multifactorial targeting issue

Thiamine (vitamin B1) deficiency, the underlying cause of Wernicke–Korsakoff syndrome, is associated with the development of focal neuronal loss in vulnerable areas of the brain. Although the actual mechanism(s) that lead to the selective histological lesions characteristic of this disorder remain unresolved, oxidative stress has been shown to play a major role in its pathophysiology. In this review, the multifactorial influence of oxidative stress on a variety of processes known to take part in the development of structural lesions in TD including excitotoxicity, neuroinflammation, blood–brain barrier integrity, mitochondrial integrity, apoptosis, nucleic acid function, and neural stem cells will be discussed, and therapeutic strategies undertaken for treating neurodegeneration examined which may have an impact on the future treatment of this important vitamin deficiency.     

Multiple roles of glucose-6-phosphatases in pathophysiology: State of the art and future trends

Background

The endoplasmic reticulum enzyme glucose-6-phosphatase catalyzes the hydrolysis of glucose-6-phosphate to glucose and inorganic phosphate. The enzyme is a part of a multicomponent system that includes several integral membrane proteins; the catalytic subunit (G6PC) and transporters for glucose-6-phosphate, inorganic phosphate and glucose. The G6PC gene family presently includes three members, termed as G6PC, G6PC2, and G6PC3. Although the three isoforms show a moderate amino acid sequence homology, their membrane topology and catalytic site are very similar. The isoforms are expressed differently in various tissues. Mutations in all three genes have been reported to be associated with human diseases.

Scope of review

The present review outlines the biochemical features of the G6PC gene family products, the regulation of their expression, their role in the human pathology and the possibilities for pharmacological interventions.

Major conclusions

G6PCs emerge as integrators of extra- and intracellular glucose homeostasis. Beside the well known key role in blood glucose homeostasis, the members of the G6PC family seem to play a role as sensors of intracellular glucose and of intraluminal glucose/glucose-6-phosphate in the endoplasmic reticulum.

General significance

Since mutations in the three G6PC genes can be linked to human pathophysiological conditions, the better understanding of their functioning in connection with genetic alterations, altered expression and tissue distribution has an eminent importance.