Anaerobic growth of Escherichia coli on formate by reduction of nitrate,fumarate, and trimethylamine N-oxide

Anaerobic growth of E. coli, strain K-10, depending on formate oxidation by nitrate, fumarate, and trimethylamine N-oxide was followed in a medium containing peptone. The presence of formate and peptone was indispensable for growth with fumarate and trimethylamine N-oxide reduction. While there was no growth in the absence of acceptor, growth was observed in the absence of formate by nitrate reduction though not as much as under aerobic conditions. Per mole consumed formate equimolar succinate or trimethylamine was formed, but 1.2 mole of nitrite was produced, probably depending partly on peptone oxidation. The molar growth yield on formate was found to be 6.5, 7.6, and 7.0 g cells/mole depending on the reduction of nitrate, fumarate, and trimethylamine N-oxide, respectively, suggesting the formation of one mole ATP coupled to the anaerobic electron transfers from formate.     

Growth kinetics of Rhodotorula rubra on different substrates

The growth of a red-pigmented yeast, isolated from yogurt and identified as Rhodotorula rubra, was studied on various industrial and agricultural by-products. Peat hydrolysate when supplemented with peptone and yeast extract supported a satisfactory growth of the yeast. Ammonium hydroxide and ammonium sulfate were the best inorganic nitrogen sources. A yield of 11.8 g/1 was obtained on molasses and wort used in a concentration of 10 and 40% (v/v), respectively. Molasses were pre-treated to be effective. The best yield of 14 g/1, however, was obtained on a richer medium composed of molasses, peptone and yeast extract. The pH profiles were also studied and growth was found within a broad pH zone of 3–10.     

Update on the relationship between magnesium and exercise.

Magnesium is involved in numerous processes that affect muscle function including oxygen uptake, energy production and electrolyte balance. Thus, the relationship between magnesium status and exercise has received significant research attention. This research has shown that exercise induces a redistribution of magnesium in the body to accommodate metabolic needs. There is evidence that marginal magnesium deficiency impairs exercise performance and amplifies the negative consequences of strenuous exercise (e.g., oxidative stress). Strenuous exercise apparently increases urinary and sweat losses that may increase magnesium requirements by 10-20%. Based on dietary surveys and recent human experiments, a magnesium intake less than 260 mg/day for male and 220 mg/day for female athletes may result in a magnesium-deficient status. Recent surveys also indicate that a significant number of individuals routinely have magnesium intakes that may result in a deficient status. Athletes participating in sports requiring weight control (e.g., wrestling, gymnastics) are apparently especially vulnerable to an inadequate magnesium status. Magnesium supplementation or increased dietary intake of magnesium will have beneficial effects on exercise performance in magnesium-deficient individuals. Magnesium supplementation of physically active individuals with adequate magnesium status has not been shown to enhance physical performance. An activity-linked RNI or RDA based on long-term balance data from well-controlled human experiments should be determined so that physically active individuals can ascertain whether they have a magnesium intake that may affect their performance or enhance their risk to adverse health consequences (e.g., immunosuppression, oxidative damage, arrhythmias).     

Factors influencing the production of kanamycin by Streptomyces canus

The production of kanamycin by three species of Streptomyces and four fermentation media was studied. Streptomyces canus in medium No. 2 gave the highest yields of kanamycin after 72 hrs. of fermentation. The presence of both molasses and glucose in the fermentation medium was an important factor for the production of kanamycin. The best concentration of molasses and glucose were 15.0 and 10.0 g/1, respectively. Replacement of peptone by equal amounts of inorganic and organic nitrogen sources was not suitable for the production of kanamycin, and peptone in a concentration of 5.0 g/1 gave the best results.     

Study of magnesium level in myocardium and aorta tissues from subjects free of ishemic necrosis (author's transl)]

Before carrying out a study on the levels of magnesium in the myocardium and the aorta in subjects who had died of coronary thrombosis, we determined the reference levels of magnesium in the right and left ventricles and in the aorta of sixteen normal subjects. The samples were homogenized and digested with nitric acid/hydrochloric acid mixture before the measurement itself was made; this was carried out by atomic absorption spectrophotometry. The magnesium values are expressed in microng/g of wet tissue, in mg/g of tissular proteins, in mg/ of total lipids in the aortic wall. The differences between the concentrations of proteins or magnesium in the left and right ventricles are significant magnesium in the left and right ventricles are significant (P less than 0,001). They probably derive from anatomic and physiological differences. We have found a correlation which is significantly positive between magnesium level and protein level in the ventricle. In the aorta, the results for proteins, lipids and magnesium are extremely dispersed because of the heterogeneous nature of biochemical composition of this tissue according to age and area which it has been taken from.     

Early onset of a decreased intracellular magnesium and phosphate concentration in smooth muscle cell of SHR.

A decrease in total magnesium content is not a direct proof of a decreased magnesium ion concentration. It could reflect a phosphate alteration or an ATP metabolism disorder. Plasma phosphate levels are lower in spontaneously hypertensive rats (SHRs) than in Wistar-Kyoto rats (WKYs), and defects in membrane regulation or mitochondrial ATP synthase occur. Only sparse data exist concerning cellular magnesium and phosphate concentrations in hypertensive cells. In aortic smooth muscle cells from 10 SHRs of the Münster strain and 10 age-matched normotensive WKY rats, the intracellular phosphate and magnesium content was measured by electron probe X-ray microanalysis (Camscan CS 24 apparatus, Cambridge, U.K.). The Mg++ content was 0.09 +/- 0.15 g/kg dry weight in SHRs versus 1.15 +/- 0.10 g/kg dry weight in WKY rats (p < 0.01). Vascular smooth muscle phosphate content was 23.6 +/- 0.79 g/kg dry weight in WKY rats versus 15.81 +/- 1.22 g/kg dry weight in SHRs (p < 0.01). In aortic smooth muscle cells of one month old SHRs intracellular magnesium was measured as 1.05 +/- 0.08 versus 1.09 +/- 0.09 g/kg dry weight in WKYs. Intracellular phosphate concentration in one month old SHRs was 18.71 +/- 2.41 versus 21.36 +/- 1.25 g/kg dry weight in WKYs (eight animals in each group). Aortic smooth muscle cells of SHRs are caracterized by markedly lowered intracellular phosphate and magnesium concentrations, resulting in an altered ATP-metabolism, as described earlier. Possibly a membrane defect or a magnesium deficiency or disturbed magnesium channels are responsible for the early onset in the pathogenesis of primary hypertension.     

纯镁超声微弧氧化-硅烷-黄芪甲苷复合处理层的 细胞相容性

目的 为了调节纯镁的降解性与提高生物活性,对其表层采取超声微弧氧化（UMAO）、硅烷化、载黄芪甲苷复合处理方法,分析各种处理方法对成骨细胞生物相容性的影响大小。方法 以纯镁微弧氧化UMAO为对照组（A组）,纯镁微弧氧化UMAO-硅烷（B组）,纯镁微弧氧化UMAO-硅烷-100 μg/ml黄芪甲苷（C组）为实验组,通过Cell Counting Kit（CCK-8）试剂盒、扫描电镜、激光共聚焦显微镜等方式检测不同处理膜层细胞相容性。结果 CCK-8粘附与增殖实验测定的吸光率C组超过B组,B组超过A组,膜层表层细胞粘附及增殖随着时间的推移呈现出不断增加的趋势,其中纯镁微弧氧化UMAO-硅烷-100 μg/ml黄芪甲苷复合膜层具有最优的成骨细胞活性,并具有统计学意义（P＞0.05）。结论 纯镁微弧氧化UMAO-硅烷-100 μg/ml黄芪甲苷复合处理后膜层的细胞相容性最好,纯镁微弧氧化UMAO-硅烷处理次之,纯镁UMAO组最低。     

Enrichment for Plesiomonas shigelloides from stools.

Bile peptone broth and alkaline peptone water (pH 8.5) were examined as enrichment media for the isolation of Plesiomonas shigelloides from stools, with salmonella-shigella agar as the isolation medium. After 423 parallel examinations in two different experiments, bile peptone broth enrichment for 24 h was observed to be six times more effective (P less than 0.01) than direct plating alone on salmonella-shigella agar. Bile peptone broth was found to be twice as effective as alkaline peptone water for the recovery of P. shigelloides from stools.     

The ontogeny of the postingestive inhibitory effect of peptone in rats

The ontogeny of the postingestive inhibitory control of intake by protein digestion products was investigated by administering gastric preloads of a peptone that was a hydrolysate of meat and that decreased intake in adult rats [Am. J. Physiol., Regul. Integr. Comp. Physiol. 276 (1999) R1623; Am. J. Physiol., Regul. Integr. Comp. Physiol. 277 (1999) R1144]. Gastric preloads of saline or peptone, or sham preloads were given 5 min before a 30-min, independent ingestion test in which pups had access to a sweet, high-fat milk diet. Preloads of isotonic peptone reduced intake significantly more than preloads of isotonic saline on postnatal day (P) 18, but not on P12. Pretreatment with the CCKA receptor antagonist devazepide (600 microg/kg ip) did not change the inhibitory effect of isotonic peptone. Thus, the inhibitory effect of peptone on P18 was apparently not mediated by endogenous CCK acting at CCKA receptors. In contrast to isotonic peptone, preloads of hypertonic peptone did not decrease intake more than preloads of hypertonic saline on P12, P18, or P24. We conclude that if the isotonic peptone used in these experiments is an adequate model of the digestion products of dietary protein at these postnatal ages, then the postingestive inhibitory control of intake by digestion products of dietary protein during independent ingestion appears between P13 and P18.     

Comparison of colicine production and diffusion on different solid media

Using a freezing-thawing method for extracting colicine from solid media it has been shown that the choice of media for production and diffusion is important. Digest nutrient agar yielded the most colicine and peptone water agar the least. A factor in bacteriological peptone, but absent in a proteose peptone (Difco) and Neopeptone, was responsible for inhibiting production on peptone water agar. Dextrose reduced the diffusion of colicine. A minimum of six hours' incubation of the colicinogenic organism was required for satisfactory production of colicine.     

The possible role of magnesium in protection of premature infants from neurological syndromes and visual impairments and a review of survival of magnesium-exposed premature infants.

The survival rate of very preterm, low birth weight infants (weighing less than 1500 g) is 85 per cent in the USA and is ever increasing, while 42 to 75 per cent of extremely premature infants (weighing 751-1000 g) survive. Of great concern is the lack of consistent decrease in neurological syndromes and associated visual impairments. Because of short gestations, these infants have not had time to accrue up to 80 per cent of magnesium normally present at term. These very preterm infants are at highest risk for cerebral hypoxia/ischemia (H/I), intracranial hemorrhage (ICH), periventricular leukomalacia (PVL) or cystic PVL (CPVL), and possible sequelae, cerebral palsy (CP) and mental retardation (MR). These syndromes are associated with damage to optic structures and the visual pathways which traverse the brain. Visual defects are common in surviving preterm infants. Increased levels of harmful neurochemical mediators that have been reported in these conditions include oxygen free radicals, excitatory amino acids, tumor necrosis factor-alpha (TNF-a), and thromboxane A2 (TXA2) which are aggravated in magnesium deficiency and may be ameliorated by magnesium. We review the published data concerning the effects of prenatal magnesium supplementation on ICH, CPVL, CP and MR and available reports concerning survival. Further considerations on the safety and efficacy of magnesium sulphate administration given prenatally to the preterm neonate await the outcome of three trials that are continuing for more than a year on three continents.     

Importance of decreased intracellular phosphate and magnesium concentrations and reduced ATPase activities in spontaneously hypertensive rats.

A decrease in total magnesium content is not a direct proof of a decreased magnesium ion concentration. It could reflect a phosphate alteration or an ATP metabolism disorder. Plasma phosphate levels are lower in spontaneously hypertensive rats (SHRs) than in Wistar-Kyoto (WKY) rats, and defects in membrane regulation or mitochondrial ATP synthase occur. Only sparse data exist concerning cellular magnesium and phosphate concentrations in hypertensive cells. In aortic smooth muscle cells from 10 SHRs of the Münster strain and 10 age-matched normotensive WKY rats, the intracellular phosphate and magnesium content was measured by electron probe X-ray microanalysis (Camscan CS 24 apparatus, Cambridge, U.K.). The Mg++ content was 0.90+/-0.15 g/kg dry weight in SHRs versus 1.15+/-0.10 g/kg dry weight in WKY rats (p<0.05). Vascular smooth muscle phosphate content was 23.6+/-0.79 g/kg dry weight in WKY rats versus 15.81+/-1.22 g/kg dryweight in SHRs (p<0.01). In seven animals, erythrocytic ATP content was 180.2+/-102 in SHRs vs. 432+/-72 micromol/L cells in WKY rats (p< 0.01). The Na+/K+-ATPase activity was significantly decreased in hypertensive animals as compared to controls (6.49+/-2.3 vs. 12.64+/-2.9 nmol inorganic phosphate/mg protein/min (p< 0.01)). Aortic smooth muscle cells from SHRs are characterized by markedly lowered cellular phosphate and magnesium concentrations and an altered ATP metabolism, possibly due to a membrane defect or a magnesium deficit in hypertensive cells.     

Effect of intravenous magnesium on ventricular tachyarrhythmias associated with acute myocardial infarction.

Ventricular ectopy and left ventricular dysfunction are important predictive factors for an unfavourable outcome following an acute myocardial infarction (MI). Tachyarrhythmias are a major cause of death subsequent to MI. Magnesium was postulated to have an antiarrhythmic effect after MI. Therefore we have investigated the influence of intravenous and oral magnesium (Mg) therapy on ventricular tachyarrhythmias. 67 patients with myocardial infarction (MI) diagnosed according to the WHO criteria of anamnesis, infarct-specific electrocardiogram (ECG), and enzymatic status were included in a prospective study. 23 patients (group 1) received 2 g Mg per day (= 82 mmol Mg/24 h) intravenously for the first 3 days followed by oral magnesium adipate administration of 3 x 2 coated tablets of magnesium 50 Apogepha (= 300 mg Mg/24 h or 12.34 mmol Mg/24 h, respectively) for the full duration of the study. 26 patients (group 2) received only i.v. magnesium for the first 3 days after admission (2 g Mg/24 h). The results of this treatment were compared to those of a control group of 18 MI patients without magnesium administration. All groups were identical with regard to other forms of treatment. The magnesium levels in serum and erythrocytes of all patients were measured at the following time points: days 0 (admission time), 1, 2, the day of discharge (about day 20) and after 12 weeks. The tachyarrhythmias were monitored by 24-h-continuous-electrocardiography on days 0, 1 and on the day before discharge (about day 20). The serum magnesium levels rose significantly during i.v. Mg-administration (1 and 2 day) but decreased in group 2 subsequently until the time of discharge from hospital. In contrast group 1 patients receiving oral as well as intravenous magnesium did not show this drop. The uptake of magnesium into the erythrocytes was less obvious. The erythrocyte magnesium concentration of the control group remained significantly low in serum and red blood cells. Significantly less ventricular premature beats and runs (< 5 ventricular premature beats and > 5 ventricular premature beats) compared to admission day were observed in both treated groups. These data suggest that the frequency of ventricular tachyarrhythmias is reduced by administration of intravenous magnesium and support an early high dose administration of intravenous magnesium in the wake of myocardial infarction.     

The role of cholecystokinin in inhibition of gastric emptying by peptone in the rat.

It is clear that the intestinal hormone cholecystokinin (CCK) inhibits gastric emptying, but doubts remain about the physiological significance of this action. Evaluation of the apparently conflicting data is complicated by the fact that little is known of the duration of action of CCK-releasing meals in delaying emptying. We have studied this issue by following the emptying of the second of two successive liquid test meals instilled into the stomach in conscious gastric fistula rats. Prior administration of peptone, but not saline, delayed the emptying of subsequently administered saline and delayed still further the emptying of subsequently administered peptone. The action of isotonic peptone lasted about 10 min from the initial instillation into the stomach. Radioimmunoassay of plasma CCK indicated a significant increase 5 min after intragastric peptone, and a still further rise occurred 5 min after administration of the second of two consecutive peptone meals; 21 min after the first meal, plasma CCK had returned to basal levels. Intravenous infusion of CCK in a dose that matched the inhibition of gastric emptying caused by peptone gave plasma concentrations about 35% higher than those seen 5 min after the second of two consecutive peptone meals. It is concluded that a liquid test meal of peptone delays gastric emptying in part through release of CCK and that the response lasts 10 min or less. The relatively short duration of action of endogenous CCK released by a single protein-rich meal in the rat should be kept in mind in interpreting the significance of studies on the physiology of CCK.     

Women with fibromyalgia have lower levels of calcium, magnesium, iron and manganese in hair mineral analysis

Little is known about hair mineral status in fibromyalgia patients. This study evaluated the characteristics of hair minerals in female patients with fibromyalgia compared with a healthy reference group. Forty-four female patients diagnosed with fibromyalgia according to the American College of Rheumatology criteria were enrolled as the case group. Age and body mass index-matched data were obtained from 122 control subjects enrolled during visit for a regular health check-up. Hair minerals were analyzed and compared between the two groups. The mean age was 43.7 yr. General characteristics were not different between the two groups. Fibromyalgia patients showed a significantly lower level of calcium (775 μg/g vs 1,093 μg/g), magnesium (52 μg/g vs 72 μg/g), iron (5.9 μg/g vs 7.1 μg/g), copper (28.3 μg/g vs 40.2 μg/g) and manganese (140 ng/g vs 190 ng/g). Calcium, magnesium, iron, and manganese were loaded in the same factor using factor analysis; the mean of this factor was significantly lower in fibromyalgia group in multivariate analysis with adjustment for potential confounders. In conclusion, the concentrations of calcium, magnesium, iron, and manganese in the hair of female patients with fibromyalgia are lower than of controls, even after adjustment of potential confounders.     

Organ culture studies of rat antrum: evidence for an antral inhibitor of gastrin release

The regulation of gastrin release in rodent antral mucosal organ cultures was investigated. The tissue was well preserved morphologically and medium gastrin concentration increased steadily throughout a 24-h culture period. The effects of peptone and a bovine serum albumin digest on gastrin release were independently investigated. During the periods these agents were in contact with the tissue, medium gastrin concentration did not differ from those of control cultures. However, treatment cultures released a significantly greater amount of gastrin into the medium than did control cultures during the two posttreatment periods. Prolongation of the period of exposure to peptone did not alter this secretory pattern. The rise in medium gastrin concentration that followed the removal of peptone was directly related to the medium peptone concentration and was partially inhibited by readdition of peptone to cultured antral explants. These results suggest that substances which stimulate gastrin release in vivo may cause the accumulation of an antral inhibitor of gastrin release when exposed to rat antral mucosa in culture.     

The influence of magnesium supplementation on magnesium and calcium concentrations in hair of children with magnesium shortage.

46 children, aged 2-6 years, with decreased magnesium concentrations in hair, were studied. Magnesium supplementation consisted of Asmag preparation for 3 months and multivitamin Multi-tabs preparation (containing magnesium, but without calcium) for the following 4 months. Control studies were performed again after 7 months of treatment, i.e. 12 months after the initial measurements (the same season of the year--early spring). The results proved increases of both magnesium (from 7.74 microg/g dry mass to 11.03 microg/g dry mass) and calcium (from 159.82 mg/g dry mass to 191.60 mg/g dry mass) concentrations in hair. Increased magnesium concentrations were observed in 40 studied children (86.95 per cent). Post supplementation magnesium deficiency was found in 22 children (47.83 per cent), and four children (8.70 per cent) showed further worsening of hypomagnesemia. Increased calcium concentrations were found in 42 children (91.30 per cent), while decreased Ca levels were found in 4 children (8.70 percent). The achieved results indicate a positive influence of that form of compensation of magnesium deficiency, and suggest the need of individual selection of doses and period of Mg supplementation. The initial level of hypomagnesemia, presence of factors that might inhibit intestinal absorption, accompanying diseases that might cause decrease in magnesium concentration and other factors that might influence the total body magnesium concentration should be taken into account while designing the supplementation therapy.     

Diagnosis of magnesium-induced diarrhea

BACKGROUND. There is no specific method of diagnosing magnesium-induced diarrhea. Therefore, the frequency and clinical importance of diarrhea caused by magnesium are unknown. The purposes of this study were to establish a method for diagnosing magnesium-induced diarrhea and to apply it to patients with chronic diarrhea. METHODS. We measured fecal output of soluble magnesium and fecal magnesium concentration in 19 normal subjects with formed stools (15 collection periods), with non-magnesium-induced diarrhea (36 collection periods), and with diarrhea induced by magnesium hydroxide alone (11 collection periods) or in combination with phenolphthalein (3 collection periods), and in 359 patients with chronic diarrhea. RESULTS. The upper limits of fecal output of soluble magnesium and fecal magnesium concentration in normal subjects were 14.6 mmol per day and 45.2 mmol per liter, respectively. When normal subjects had diarrhea due to the ingestion of magnesium hydroxide alone or in combination with phenolphthalein, fecal magnesium output was always abnormally high. For each millimole increase in fecal magnesium output, fecal weight increased by approximately 7.3 g. The fecal magnesium concentration was very high when magnesium was the only cause of diarrhea but only moderately elevated when diarrhea was induced by magnesium hydroxide plus phenolphthalein. Biochemical and clinical evidence indicated that excessive ingestion of magnesium was an important cause of chronic diarrhea in 15 of the 359 patients with chronic diarrhea (4.2 percent), if not the only cause. CONCLUSIONS. Quantitative fecal analysis for soluble magnesium is an accurate method of diagnosing magnesium-induced diarrhea. Some patients with chronic diarrhea ingest excessive amounts of magnesium (in antacids or food supplements), and physicians may fail to discover this before embarking on an expensive and invasive diagnostic evaluation.     

Tumour Growth and Non-Specific Immunity in Rats: The Mechanisms Involved in Inhibition of Tumour Growth

Various non-specific in vivo stimulants of phagocytosis, such as peptone, starch, glycogen, BCG, inhibit the growth of Walker carcinosarcoma in rats. This was confirmed by comparison of the histological appearance of tumour beds and tumours of peptone-treated and control rats. In rats given peptone or BCG, tumour inhibition was detectable only during a limited period of time. Experiments on the effect of pretreatment with peptone on the growth of Walker ascites tumour cells revealed a clear-cut inhibition, and suggest that tumour cells may be successfully eliminated during the lag phase. Data showing that activated macrophages labelled with ⁵¹Cr significantly accumulate around the tumour implant support the view that macrophages are of prime importance in the elimination of tumour cells in this model system.     

Effect of a low magnesium diet on in vitro glucose uptake in sucrose fed rats.

Dietary magnesium deficiency and excess sucrose in the diet have been shown to play an important role in the development of insulin resistance. This study is an extension of a previously published experiment (Magnes Res 2004; 17: 293-300) and is focused on the effect of a low magnesium diet on in vitro glucose uptake in sucrose fed rats. For this purpose male Wistar rats were divided into four groups and fed control, high sucrose, low magnesium and high sucrose low magnesium diets for a period of three months. Serum and erythrocyte magnesium values demonstrated a significant drop in the low magnesium and high sucrose low magnesium groups. A significant increase was observed in the body weight of the high sucrose group, whereas the weights of animals in the high sucrose low magnesium group remained unchanged from controls. The biochemical analysis showed a significant decrease in in vitro glucose uptake in liver, muscle and diaphragm of rats consuming high sucrose, low magnesium and high sucrose low magnesium diets. The maximum reduction, however, was observed in the combined high sucrose low magnesium group. These findings seem to suggest the potential of a high sucrose low magnesium diet to cause insulin resistance by reducing glucose uptake in target tissues of rats.