Respiration in the sapwood and heartwood of Robinia pseudoacacia

The respiratory activity of distinct sapwood and heartwood annual rings of the stem of Robinia pseudoacacia L. has been investigated. The oxygen uptake and the carbon dioxide release in the inner parts of the sapwood is enhanced in comparison with that in the outer parts. The heartwood rings have no measureable gas exchange.     

Peroxidase and amylase isoenzymes in the sapwood and heartwood of trees

Peroxidases and amylases have been found in the sapwood and the heartwood of both angiosperm and gymnosperm trees. Cambial and outer layers of xylem of     

Wood anatomy and heartwood formation in Neem (Axadirachta indica A. Juss.)

The wood of Azadirachta indica is diffuse porous. Axial parenchyma is paratracheal banded or vasicentric. Rays are uniseriate to multiseriate and heterocellular with procumbent and upright cells. There is a strong negative correlation between vessel member length and diameter. The vulnerability and mesomorphic values are different in two trees of almost the same age growing in the same locality. The vessel member wall has spiral thickenings on its inner surface. Axial and ray parenchyma cells and sometimes vessels and fibres of the heartwood show the presence of extractives. The necrobiosis of the parenchyma cells occurs at the heartwood boundary. Senescence and death of parenchyma cells are associated with depletion of starch grains and accumulation of extractives. There is a climacteric rise in succinate dehydrogenase and acid phosphatase activities at the sapwood-heartwood interface which may be associated with heartwood formation. Peroxidase activity is greater near the cambial zone, indicating its probable role in lignification.     

Sugar-related hydroxy acids from Phaseolus and trifolium species

-Hydroxy acids isolated from leaves of French bean (Phaseolus vulgaris) and clover (Trifolium incarnatum) were analysed by GLC as trimethylsilyl derivatives and identified by MS. Large amounts of a 2-C-methyltetronic acid and appreciable amounts of gluconic acid and of a 2-C-(hydroxymethyl)pentonic acid were found from French bean. Glyceric acid was the predominant acid from clover but the presence of several other acids, e.g. threonic and malic acids, was also demonstrated.     

Aporphine alkaloids and lignans in heartwood of Liriodendron tulipifera

The following compounds were isolated from heartwood of Liriodendron tulipifera: glaucine, dehydroglaucine, asimilobine, N-acetylnornuciferine, norushinsunine, liriodenine, O-methylatheroline, (+)-syringaresinol, (+)-syringaresinol dimethyl ether and syringaldehyde. The occurrence of 1-benzyltetrahydroisoquinoline alkaloids also has been indicated by mass spectroscopy. Some characteristic spectral properties of these aporphine alkaloids and their probable biosynthetic pathways are discussed.     

Analysis of acid-soil stress in sorghum genotypes with emphasis on aluminium and magnesium interactions

Acid-soil stress in 12 sorghum (Sorghum bicolor (L.) Moench) genotypes was attributed mainly to aluminium (Al) toxicity. Root damage and magnesium (Mg) deficiency are two independent aspects of plant sensitivity to Al, either in acid soil or in nutrient solution. At moderate soil acidity, Mg deficiency dominantly limited growth whilst at high acidity root damage overruled the effect of Mg deficiency on the growth response. In nutrient solutions containing Al, increased Mg supply improved both root development and Mg nutrition of plants, whereas increased calcium (Ca) supply, or nutrition with ammonium (NH₄) instead of nitrate (NO₃), alleviated root damage but amplified Mg deficiency. At lowered pH the syndrome of Al toxicity was more profound. The implications of Mg-Al interactions, root damage, Mg supply and genotype selection are elucidated.     

Esterified long-chain hydroxy acids in green and senescent parts of the peat moss Sphagnum fuscum

The bifunctional long-chain acids in extracts and alkaline hydrolysates of extractive-free tissues from the green and senescent parts of Sphagnum fuscum were investigated by GC and GC/MS. A series of C₁₄– C₂₆hydroxy acids was liberated by alkaline hydrolysis of senescent tissue demonstrating the presence of insoluble polymeric lipid esters in the moss. In the corresponding hydrolysates of the topmost green parts of the shoot the amounts of these acids were significantly smaller. It is suggested that the presence of such polymeric esters in S. fuscum contributes to the cell-wall resistance of this peat-forming moss.     

Empirical models to approximate calcium and magnesium ameliorative effects and genetic differences in aluminium tolerance in wheat

The activities of inorganic, monomeric aluminium (Al) species in the root environment are important in the toxicity of Al to plant roots, which may be ameliorated by increased activities of basic cations. Additionally, it has been suggested that electro-chemical processes in walls of root cells play a role in Al tolerance. Empirical models were proposed to accomodate genetic and calcium (Ca) and magnesium (Mg) ameliorative effects on Al toxicity. The models were tested using data from a solution culture study (with ionic strength 1.6 to 8.6 mM) in which wheat (Triticum aestivum L.) cvv. Warigal (Al-sensitive) and Waalt (Al-tolerant) were grown for 28 d at 0, 10 and 20 M Al, in factorial combination with 200, 400, 800 and 1600 M Ca and 100, 200, 400 and 800 M Mg. There was a poor relationship between relative total dry mass (TDM) (calculated as a percentage of the average TDM of each cultivar in the absence of added Al) and the activity of Al³⁺ or the sum of the activities of the monomeric Al species in solution. A model based on the ratios of activities of cations in solution, taking valency into consideration, was more successful, accounting for ca 85% of the observed variation in relative TDM. There were no systematic variations between observed values and those estimated by the model.     

Weak relationship between ionized and total magnesium in serum of patients requiring magnesium status

Measurement and monitoring of magnesium (Mg) are important to prevent the development of serious and potentially fatal complications in critically ill patients. Although ion-selective electrodes are available and earlier reports suggest that free ionized magnesium (iMg²⁺) is the most useful test to estimate Mg status, most clinical laboratories still only measure total Mg. To compare the relationship among iMg²⁺, total Mg, and albumin in serum, samples were collected from 48 consecutive patients admitted to an intensive care unit or a primary health center. The mean serum level of iMg²⁺ in 44 patients was 0.53 mmol/L, the total Mg was 0.06 mmol/L, and the albumin was 34.93 g/L. The correlation between iMg²⁺ and total Mg in serum was r=0.585; the correlation between iMg²⁺ and albumin in serum was r=378; and the correlation between total Mg and albumin in serum was r=0.340. The mean percent iMg²⁺ in relation to total Mg in serum was calculated to be 55% in the patient samples. The important level of biologically active iMg²⁺ was not reflected upon analysis of total Mg in 25% of consecutive patients. This report shows that the correlation of iMg²⁺ and total Mg is weak, not only in critically ill patients but also in patients in whom Mg status is inquired as a whole.     

Interactions between aluminium,magnesium and calcium with different monocotyledonous and dicotyledonous plant species

Growth inhibition of plants suffering from Al toxicity is generally accompanied by impaired root development which can be quantitatively described by reduced specific root length (m g^-1 dry root). In addition, the uptake of nutrients such as Mg and Ca is inhibited. Increased supply of either Mg or Ca can significantly diminish the negative effect of Al on root development and improve the Mg or Ca nutrition of the plants. The positive effect of Ca is well established but the effect of Mg has been observed in only a few plan species. Therefore, the effects of increasing Mg and Ca supply on Al toxicity in plants of seven monocots and eight dicots have been now examined in nutrient solution experiments. In general, Mg appears to be more effective than Ca in alleviating Al toxicity with the monocots, whereas the reverse is true for the dicots. Increased concentrations of Mg and Ca in solution seem to protect the plants against Al toxicity by improving the Mg or Ca nutrition and by alleviating the toxic effect of Al on root development.     

Characterization of magnesium and calcium tenuazonate from Phoma sorghina

Phoma sorghina Sacc., the fungus implicated in the aetiology of onyalai, a haematologic disorder, produces magnesium and calcium tenuazonate as toxic constituents.     

黑龙江不同区域人工红松心边材及树皮削度可加性模型系统构建

基于黑龙江省孟家岗林场、东京城林业局和林口林业局不同林分条件下103株人工红松解析木的2977个圆盘数据,结合林业研究中常见的Kozak(1988)、Muhairwe(1999)、Lee(2003)、Kozak(2004)可变指数削度方程,构建带皮直径、心材直径、边材宽度、树皮厚度的削度方程,并对比选出最优基础模型;采用SAS软件PROC MODEL模块中似乎不相关回归(SUR),建立带皮直径、心材直径、边材宽度和树皮厚度削度方程的可加性模型系统,同时将区域作为哑变量引入模型中,通过调整确定系数(R_adj²)、均方根误差(RMSE)、赤池信息准则(AIC)、贝叶斯信息准则(BIC)等模型评价指标,对模型进行综合评价。结果表明: 带皮直径、心材直径、边材宽度和树皮厚度最优基础模型均为Kozak(2004);可加性模型系统在满足各分量与总量可加性的基础上,也得到较好的预测效果,预估精度均达到98%以上,引入哑变量后,可加性模型系统预测能力均有不同程度的提升,尤其心材直径和边材宽度预测能力提升更显著;不同区域带皮直径和树皮厚度削度差异较小,而心材直径、边材宽度的削度存在明显差异。本研究构建的包含哑变量可加性模型系统,不但模型预测精度较高,还满足带皮直径、心材直径、边材宽度和树皮厚度之间的可加性逻辑,为人工红松心边材及树皮材积的准确估测提供了基础。     

Cardiac copper,magnesium, and zinc in recent and old myocardial infarction

X-ray fluorescence spectrometry and atomic absorption spectrometry were used in a quantitative study of zinc, copper, and magnesium in 71 postmortal human hearts. Samples were obtained from individuals who had demonstrated no previous clinical or subsequent pathological findings of myocardial infarction and from victims of a recent or an old infarction. A significant difference (p<0.001) in the elemental levels was observed between the noninfarct and the recent infarct groups. The noninfarct group had higher cardiac levels of all three elements. However, the difference in elemental concentrations between the noninfarct and the old-infarct groups was not significant. Cardiac levels of zinc (p<0.001) and copper (p<0.01) were significantly greater in the old-infarct group than in the recent-infarct group. Magnesium levels were higher in the recent-and-old-infarct group than in the recent infarct group (p<0.01). It is possible that the elements are redistributed during myocardial infarction, and that uptake of these elements (from the serum pool) by the heart may be important in maintaining myocardial integrity and function.     

Lactobacilli prevent hydroxy radical production and inhibit Escherichia coli and Enterococcus growth in system mimicking colon fermentation

Aims: To explore the effect of Lactobacillus on redox state of colon chyme. Methods and Results: Nine Lactobacillus strains were studied for the inhibition of lipid peroxide formation in Fe²⁺/ascorbate system and for their ability to chelate ‘free’ ferrous ion. The result shows both properties were strain specific and no relationship between them was found. Both properties of Lactobacillus paracasei Fn032, Lactobacillus rhamnosus GG (LGG) and Lactobacillus sp. Fn001 were successively decreasing. LGG and Fn032 significantly decreased hydroxyl radicals (P < 0·01) in colonic fermentation model, in which considerable hydroxyl radicals occurred spontaneously. Addition of ferrous ion induced the production of hydroxyl radicals, which could be significantly inhibited by LGG, Fn032 (P < 0·01) and Fn001 (P < 0·05). Ferrous ion significantly induced the growth of Enterococcus and Escherichia coli, which could be inhibited by all three Lactobacillus strains. Escherichia coli and Enterococcus show significantly positive correlation with hydroxyl radicals with R of 0·96 (P = 0·0002) and 0·91 (P = 0·0017), respectively. Conclusions: Antioxidative Lactobacillus could modulate redox state in colonic fermentation system, which is related to their free radical–scavenging ability or antibacterial effect. Significance and Impact of the Study: This study proves that Lactobacillus strain could influence the redox state of gut chyme. Evaluation of antioxidative ability might be a powerful method for screening probiotic Lactobacillus strains.     

Aluminium in the brain and heart of the rainbow trout

Tissue residue analysis and aluminium-specific hifstochemistry demonstrated that the chronic exposure of rainbow trout to aluminium results in the systemic accumulation of aluminium and a distinct neuropathology in the brain. Aluminium was found associated with endothelial and epithelial surfaces including the cerebrovascular endothelium of the brain and the endothelium of the bulbus arteriosus of the heart. The potential for aluminium to compromise the barrier properties of membranes may underlie its known toxicity in fish.     

Isolation and antimicrobial evaluation of isomeric hydroxy ketones in leaf cuticular waxes of Annona squamosa

A novel natural compound, 11-hydroxy-16-hentriacontanone, has been isolated from the leaf cuticular wax of Annona squamosa along with its known isomer 10-hydroxy-16-hentriacontanone in a ratio of 67:33. This isomeric mixture of hydroxy ketones constituted together 16.5% of the total cuticular waxes. The new compound was characterised using spectral and chromatographic techniques. The major component was found to be 16-hentriacontanone (palmitone), which constituted up to 48% of the total cuticular wax, together with a homologous series of hydrocarbons, fatty aldehydes, fatty alcohols, fatty acids and sterols as minor components. The antimicrobial activity of the isomeric hydroxy ketones was tested against selected Gram-positive and Gram-negative bacterial strains, and also some selected fungal strains, and compared with palmitone. The antibacterial activity of palmitone was significantly higher than that of the isomeric hydroxy ketones, but their antifungal activities were comparable.     

Investigation of the reaction of magnesium with p-nitro-o-carboxylazochromotropic acid and the determination of magnesium in plants and in water

The formation of a novel complex between magnesium and p-nitro-o-carboxylazochromotropic acid (NCBAC) has been observed which is sensitive and selective at pH 10.4 in the presence of ethylenediamine and fluoride. The constants of formation of this complex have been determined by a spectral correction technique, and the complexation reaction has been applied to the spectrophotometric determination of trace magnesium in plants and in water with satisfactory results.     

Aluminium accumulation in root cell walls coincides with inhibition of root growth but not with inhibition of magnesium uptake in Norway spruce

High levels of aluminium in the soil solution of forest soils cause stress to forest trees. Within the soil profile, pH and aluminium concentration in the soil solution vary considerably with soil depth. pH strongly influences the speciation of A1 in solution, and is a factor when considering toxicity of A1 to roots. Norway spruce ( Picea abies [L.] Karst.) seedlings were grown for 7 weeks in nutrient solutions at pH 3.2, 4.0 or 5.0 containing 0, 100 or 400 µ M A1. At the end of this period, seedling growth, the cation exchange capacity of the roots and the amount of exchangeable Ca and Mg in roots were determined. A1 concentrations in whole roots, root segments, and in needles were measured. Using X‐ray microanalysis, the concentrations of Al, Ca, Mg and P were determined in cortical cell walls. We wanted to test the hypotheses that (1) the amount of Al bound to cation exchange sites can be used as a marker for Al toxicity and (2) the Mg concentration of needles is controlled by the amount of Mg bound to cation exchange sites. Low pH reduced the inhibition of Al on root growth and shoot length. Both low pH and Al lowered the concentration of Ca and Mg in needles. Al concentrations in the roots decreased as the pH decreased. In the roots, Al displaced Mg and Ca from binding sites at the root cortical cell walls. A comparison of the effects of Al at the different pH values on root growth and Mg concentration in the needles, suggests that, at pH 5.0, an Al fraction in the apoplast inhibits root growth, but does not affect Mg uptake. This fraction of Al is not available for transport to the shoots. In contrast, Mg uptake is strongly affected by Al at pH 3.2, although only very low levels of Al were detected in the roots. Thus, Al accumulation in the apoplast is a positive marker for Al effects on root growth, but not Mg uptake. The Mg concentration of needles is not controlled by the amount of Mg bound to cation exchange sites.     

Calcium, magnesium, and zinc status in experimental hypothyroidism

In this study, experimental hypothyroidism was established and used to investigate possible alterations in the calcium, magnesium, and zinc homeostasis by assessing their concentration in plasma and erythrocytes. Hypothyroidism was induced by administration of methimazole an iodine blocker at a dose of 75 mg/100 g food for 3 wk. In the methimazole-induced hypothyroid state, the experimental animals showed a significant decrease in plasma zinc concentration, whereas a significant increase in plasma magnesium concentration occurred. No change was observed in plasma calcium concentration. The erythrocyte zinc and calcium concentrations were found to be increased, whereas magnesium concentration decreased. Erythrocyte magnesium concentration showed a significant positive correlation with T₄ values. The study provides evidence for marked alterations in homeostatis of zinc, magnesium, and calcium.     

Analysis of zinc and magnesium levels in pinealectomized chicks

Melatonin is the main product of the pineal gland, and trace metals play a critical role in growth and development. The purpose of this study was to assess the serum zinc (Zn) and magnesium (Mg) levels in pinealec-tomized chicks and their possible interactions with the development of spinal deformity. Chicks were divided into two equal groups: unoperated controls (group M) and pinealectomized chicks (group N). Pinealectomies were performed at the age of 3 d. After 8 wk, serum Zn and Mg levels of 10 animals from each group were measured by spectrophotometric assay. The results of analyses were compared using the Mann-Whitney U-test. The correlation between serum Zn and Mg levels were assessed by Spearman's correlation. In this study, it was obvious that the serum Zn levels in group N were significantly lower than those in group M (2.8±0.10 vs 4.2±0.14 ppm; p<0.0005). In contrast, Mg levels in group N was high compared with the values in group M, although there was no significant difference (17.8±0.69 vs 15.7±0.85 ppm; p>0.05). In pinealectomized animals, serum Zn levels declined significantly while serum Mg levels increased, albeit insignificantly. Thus, there was a moderately positive but not statistically significant correlation between Mg and Zn levels in unoperated controls (r=0.273, p>0.05), whereas there was a negative but not statistically significant correlation between Zn and Mg levels in pinealectomized chicks (r=−0.115, p>0.05). In addition, the serum Mg to serum Zn ratio was significantly higher in group N than in the group M control (6.39±0.32 vs 3.75±0.22, respectively; p<0.001). From the results of the current study, it is clear that surgical pinealectomy in newly hatched Hybro Broiler chicks has a significant effect on serum Zn level. However, the serum Mg did not change significantly. Because serum Mg is not a good indicator of Mg status in chicks, it is speculated that other tissues, such as muscle or spine, might productively be explored as a more sensitive Mg biomarker for this model. The present study provides experimental evidence that serum trace metal levels might be affected in pinealectomized animals because of the lack of its main neurohormone melatonin.