Influence of the culture medium on the inhibitory activity of Arthrinium strains

Modifications in the antibiotic capacity of Arthrinium strains when they were developed in culture media of various compositions were studied. The culture media used were 2% malt extract agar, Czapek-Dox agar, Sabouraud dextrose agar, oatmeal agar, Yoshimura's medium, mixed medium of salts, modified phytone agar, malt extract-yeast extract agar, potato dextrose agar, and Wickerham's medium. The inhibition values were compared with those obtained when the strains were developed in Wickerham's medium. The media which enhanced the production of inhibitory substances were potato dextrose agar and 2% malt extract agar.     

A cis-regulatory element within the 5'' flanking region of arylsulfatase gene of sea urchin, Hemicentrotus pulcherrimus

Mycobacteria generally have thick cell walls and contain large amounts of lipid, making them resistant to DNA extraction. Five methods, namely, extensive enzymic digestion method (M1), 2-min mechanical glass-bead disruption method (M2), thermal shock method (M3), modified conventional enzymic digestion method (M4), and manual disruption with modified conventional enzymic digestion method (M5), were used to compare their effectiveness and simplicity in extracting DNA from slowly growing mycobacteria (Mycobacterium leprae, M. lepraemurium and M. bovis BCG), and a rapidly growing mycobacterium (M. phlei). The highest DNA yield was obtained by M2 from M. lepraemurium which produced 2.82 micrograms DNA/mg wet weight of cells, representing a theoretical yield of 78%. M3 gave the lowest DNA yield; 0.01 microgram DNA/mg wet weight of cells of M. lepraemurium was obtained. M4, in which proteinase K was used, is more effective than M1, in which subtilisin and pronase were used. M5 yielded a higher amount of DNA, but it required more manipulations to extract DNA as compared to M4. Extraction of DNA of M. leprae from nude mice is more difficult than that of M. leprae from armadillos by all of the methods used. These results suggest that the biosynthetic capabilities of these two forms of M. leprae may vary, depending on their cultural conditions and/or strain differences. Our results have shown that both M2 and M4 are the simplest, most effective and time-saving methods which are suitable for every routine laboratory to extract DNA from slowly and rapidly growing mycobacteria.     

Characterization of antichemotactic factor extracted from the gastric mucosa of rats

The gastric mucosa of normal rats exhibits no detectable inflammation or visible damage. We examined the effect of the gastric mucosal extract of rats on neutrophil chemotaxis and tried to purify antichemotactic factor. The chemotaxis of neutrophils was examined by the modified Boyden's method. After mucosal layer was scraped and then homogenized and centrifuged at 20,000 x g for 30 min, the supernatant was used as rat gastric mucosal extract (RGME). Prior exposure of neutrophils to the gastric mucosal extract caused a dose-dependent reduction in the neutrophil migration induced by formyl-methionyl-leucyl-phenylalanine (FMLP), leukotriene B4 (LTB4) and interleukin 8 (IL-8) without affecting the cell viability. The antichemotactic factor was partially purified by lectin affinity chromatography on wheat germ lectin (WGL)-Sepharose, anion exchange chromatography on Mono-Q and gel filtration on Superose 12. The molecular weight of the antichemotactic factor was estimated to be around 60 k by gel filtration. The activity was markedly abolished by boiling for 5 min, heating at 60 degrees C for 30 min, and treatment with 1% acetic acid, 0.1 M Na2CO3 or trypsin. Furthermore, the FMLP-induced migration of neutrophils pretreated with the antichemotactic factor for 5 min followed by washing with fresh medium was inhibited, although the factor was not added to the chamber. These results suggest that the gastric mucosa of rats intrinsically generates an antichemotactic factor which might play a crucial role in maintenance of the integrity of the gastric mucosa.     

从软锰矿酸浸沉淀渣中回收钴镍

以软锰矿酸浸工艺中除杂产生的二甲基二硫代氨基甲酸盐沉淀为原料,在酸性条件下利用硝酸钠氧化浸出钴和镍。考察硝酸钠用量、硫酸浓度、反应温度和时间等因素对钴和镍浸出效果的影响。结果表明,在硝酸钠用量35.0g/L,硫酸浓度1.84mol/L,50℃浸出3h的条件下,钴和镍的浸出率分别达到96%和94%。     

Determinants of left ventricular mass in early hypertension

Four modified cyclic hexapeptides, tenuecyclamides A-D (1-4), were isolated along with the known antibiotic, borophycin (5), from the methanol extract of Nostoc spongiaeforme var. tenue (TAU strain IL-184-6). The planar structure of tenuecyclamides A-D (1-4) was determined by homonuclear and inverse-heteronuclear 2D-NMR techniques as well as by high-resolution mass spectrometry measurements. The absolute configuration of the asymmetric centers was studied by Marfey's method for HPLC. The stereochemistry of the asymmetric centers in tenuecyclamides A and B (1 and 2) could not be fully determined, while that of tenuecyclamides C and D (3 and 4) was unambiguously determined.     

Culture medium for protocorm differentiation in Dendrodium candidum Wall. ex Lindl

Effects of basal culture medium, sucrose concentration, natural extracts and phytohormones on protocorm differentiation were studied. The suitable medium for protocorm differentiation has been found to be 1/2Ms basal medium plus 2% w/v sucrose, 2mg/L BA, 0.2mg/L NAA and 20% (w/v) potato extract.     

Selective protective effect of an extract from Fumaria parviflora on paracetamol-induced hepatotoxicity

1. The hepatoprotective activity of an aqueous-methanolic extract of Fumaria parviflora was investigated against paracetamol- and CCI4-induced hepatic damage. 2. Paracetamol (1 g/kg; orally) produced 100% mortality in mice; pretreatment of animals with the plant extract (500 mg/kg; orally) reduced the death rate to 50%. 3. Pretreatment of rats with plant extract (500 mg/kg, orally twice daily for 2 days) prevented (P < 0.001) the paracetamol (640 mg/kg)-induced rise in serum enzymes alkaline phosphatase (ALP) and transaminases (GOT and GPT), whereas the same dose of the extract was unable to prevent (P > 0.05) the CCI4-induced rise in serum enzyme levels. 4. Posttreatment with 3 successive doses of the extract (500 mg/kg, 6 hourly) also restricted the paracetamol-induced hepatic damage. 5. The plant extract (500 mg/kg; orally) caused significant prolongation in pentobarbital (75 mg/ kg)-induced sleep as well as increased strychnine-induced lethality in mice (P < 0.05), suggestive of an inhibitory effect on microsomal drug metabolizing enzymes (MDME). 6. It is conceivable therefore, that Fumaria parviflora extract exhibits a selective protective effect against paracetamol-induced hepatotoxicity, probably mediated through MDME inhibition.     

火焰原子吸收光谱法测定铜-钛改性的碳/碳-碳化硅复合材料中高含量铜

铜-钛改性的碳/碳-碳化硅(C/C-SiC)复合材料的主要成分为铜钛碳硅,不易被常规方法溶解。采用在800～820 ℃先将样品灼烧20 min以消除碳的干扰,再从瓷坩埚转于刚玉坩埚中碱熔,并加入盐酸和硝酸进一步溶解样品,建立了以2.0%盐酸为测定溶液介质、火焰原子吸收光谱法测定铜-钛改性的C/C-SiC复合材料中铜的方法。研究表明,铜浓度在2～12 μg/mL范围内与吸光度呈良好的线性关系,线性回归方程为y=0.015 31+0.059 66x,线性相关系数R=0.999 4,方法检出限为0.011 2 μg/mL。采用方法对铜-钛改性的C/C-SiC复合材料自制样品FL-2和内控样品C6分别进行测定,结果与参考值或碘量法基本一致,相对标准偏差(RSD,n=6或12)分别为0.39%和1.1%。     

Photoluminescence properties of Eu~(3+)-doped MgAl_2O_4 nanoparticles in various surrounding media

Eu~(3+)-doped MgAl_2O_4 nanoparticles were prepared by modified Pechini method.X-ray diffraction analysis shows pure tetragonal spinel phase without any impurities.The average size of synthesized nanoparticles was determined to be about 50-60 nm using scanning electron microscopy and static light scattering techniques.Emission and excitation spectra as well as lifetimes of MgAl_2O_4:Eu~(3+) nanophosphors were explored in surrounding media with different refractive indexes.Surrounding medium does not affect luminescence bands position,whereas ~5D_0 lifetime monotonically decreases along with increase of medium refractive index.Effect of surrounding media on radiative and nonradiative decay rates,which were calculated using 4f-4f intensity theory,was studied and discussed.Filling factor of prepared nanoparticles is defined using both radiative and observed lifetimes.     

Atopic eczema: a clinical psychiatric study

The method of Deutsch and Weeks was modified to provide a reliable and reasonably quick method for assaying the L-ascorbic acid content of culture medium. The modified method was used to determine the decay of L-ascorbic acid under various conditions of culture and the concentration of the vitamin in commercially prepared media. The half-life of L-ascorbic acid in a modified New circulator gassed with 95% O2 + 5% CO2 was 1.5 hr.; and when gassed with 20% O2 + 5% CO2 + 75% N2, about 2 hr. In Petri dishes gassed with 20% O2 + 5% CO2 + 75% N2, the half-life of L-ascorbic acid was 0.9 hr. About 4% of the L-ascorbic acid was lost per day when medium was stored at 0 degrees C and about 9% per day when stored at 5 degrees C. When medium with an initial content of 300 microng per ml was stored at room temperature, the half-life was found to be 15.5 hr. The L-ascorbic acid in five commercially available media, which contain the vitamin in their formulations, was assayed immediately after their delivery to the laboratory. The values of L-ascorbic acid measured in these media were in all cases far lower than prescribed. A continuous-flow organ culture system has been designed which allows the provision of a relatively constant level of L-ascorbic acid to explant by taking advantage of the slow oxidation of L-ascorbic acid at 0 degrees C.     

Optimization of Medium Composition for Production of Recombinant Calf Chymosin from Kluyveromyces lactis in Submerged Fermentation

Response surface methodology was applied to optimize medium components for production of recombinant calf chymosin by Kluyveromyces lactis GG799. The previous data indicated that the most suitable carbon source, nitrogen source, salt and vitamin were glucose, yeast extract, KH2P04 and Ca D-Pantothenate, respectively. The concentration of four media components were optimized by using central composite design of response surface methodology. The optimum medium composition for recombinant calf chymosin production was found to contain glucose 29.84 g·L<'-1>,yeast extract 19.85 g·L<'-1>,KH<'2>PO<'4> 0.1 g·L<'-1> and Ca D-Pantothenate 4.49 mg·L<'-1>.The enzyme activity of recombinant calf chymosin was 722 U·mL<'-1>,which was in an excellent agreement with the predicted value (723 U·mL<'-1>). The production of recombinant calf chymosin from Kluyveromyces lactis GG799 was effectively increased by response surface methodology.     

L-2-Hydroxyglutaric aciduria: neuropathological correlations and first report of severe neurodegenerative disease and neonatal death

Chromolaena odorata (formerly Eupatorium odoratum) is used as a traditional medicine in Vietnam (Nghiem, 1992), where its Vietnamese common name is "co hoi." While it has been widely considered a weed by agriculturalists (Holm et al., 1991), the aqueous extract and the decoction from the leaves of this plant have been used throughout Vietnam for the treatment of soft tissue wounds, burn wounds, and skin infections. A number of clinical studies done by Vietnamese as well as foreign medical workers has demonstrated the efficacy of this extract on the wound-healing process. In this article, the effect of the Eupolin extract on hydrated collagen lattice contraction by human dermal fibroblasts, an in vitro model of wound contraction, is described. The significant inhibition of collagen gel contraction by Eupolin extract at 50 to 200 micrograms/ml is demonstrated in various concentrations of collagen. When the extract at 50 to 150 micrograms/ml was washed out of the lattices and replaced by fresh medium without Eupolin, the contraction of collagen by cells was resumed. The visualization of cells in the lattices by incubation in a tetrazolium salt for 2 h showed live cells at 50 to 150 micrograms/ml of extract. In contrast, all cells were killed in the higher extract doses of 300 or 400 micrograms/ml. These preliminary results showing the inhibitory effect of Eupolin extract on collagen contraction suggest that a clinical evaluation of its effect on wound contraction and scar quality should be made. This work illustrates that traditional remedies that are used by folk practitioners to improve healing can be examined in a scientific manner using in vitro wound-healing models. It could be that the synergistic properties of components of the natural extract contribute to the positive effects demonstrated on various wound-healing mechanisms.     

Liquid preservation of canine granulocytes obtained by counterflow centrifugation-elutriation

Granulocytes (PMN) were isolated from 120 ml of canine whole blood by a modification of the counterflow centrifugation-elutriation technique. Isolated cell suspensions of 96% granulocytes and 4% mononuclear leukocytes with a 21:1 PMN/RBC ratio were stored at 4 degrees C in 4:4:2 medium consisting of four parts HBSS minus Ca++ and Mg++, four parts MEM, twp parts autologous plasma, and 20 microgram/ml gentamicin for 15 days. Granulocytes were stored at concentrations of approximately 4 x 10(6) PMN/ml in polypropylene centrifuge tubes. The stored granulocyte suspensions were assayed in vitro 0, 1, 4, 8, and 15 days to monitor chemotaxis, bacterial growth inhibition, O2 consumption associated with phagocytosis, and enzyme activities. Cell volume analysis was used to evaluate cellular integrity of the liquid-stored granulocytes. Canine granulocytes isolated by the modified dilution technique of counterflow centrifugation-elutriation can be preserved for up to 15 days with 77 +/- 6% granulocyte survival with maintenance of morphological and organelle integrity, as well as retention of in vitro functions of recognition, migration, phagocytosis, and killing of gram-negative bacteria.     

T4 and T3 release from the perfused canine thyroid isolated in situ

A method for once-through perfusion of the canine thyroid isolated in situ is described. The perfusion medium was a modified Krebs Ringer buffer with 4% dextran added. In 4 control experiments of the T4 and T3 concentratios in effluent were stable or slightly falling during 3 h perfusion. There were no significant alterations in the T4/T3 ratio in the effluent during these experiments. A 10-min infusion of bovine TSH (1 mU/ml) caused an increase in the release of T4 and T3 after 15-25 min. The T4/T3 ration in the effluent was significantly reduced after TSH stimulation. However, the ratio returned to pre-stimulation values while the hormone release was still very high. T4 and T3 content of the contralateral thyroid was determatio in the homogenate was twice as high as the T4(3 ratio in the effluent during control perfusion. Thus there was a preferential secretion of T3 from the perfused canine thyroid and this was increased after TSH stimulation.     

4-(3-吡啶基)-2-巯基咪唑修饰碳糊电极阳极溶出伏安法测定痕量银

报道了采用化合物4-(3-吡啶基)-2-巯基咪唑(PMI)修饰碳糊电极测定痕量银的阳极溶出伏安法。在0.1 mol/L的HNO3中,Ag+可以富集于PMI修饰电极表面,将介质交换至含I-的0.02 mol/L硫酸溶液中,-0.20 V还原30 s后再进行阳极溶出伏安测定,可以获得灵敏的银阳极溶出峰。一次导数峰电流与Ag+在8.0×10-10~4.0×10-6mol/L浓度范围内呈线性关系,检出限可达5.0×10-10mol/L(S/N=3)。采用本法不经过预分离,对成分复杂的定影液废液和锌合金等样品进行了直接测定,测定的回收率为92%~105%。     

Basic fibroblast growth factor and insulinlike growth factor I support the growth of human septal chondrocytes in a serum-free environment

OBJECTIVE: To determine if insulinlike growth factor I (IGF-I) and basic fibroblast growth factor (bFGF), individually or in combination, support the growth and viability of human septal chondrocytes in a serum-free medium (SFM) and a serum-enhanced culture medium. DESIGN: Chondrocytes were recovered from enzymatically digested human septal cartilage and were plated for monolayer culture in a newly developed medium. The medium included Dulbecco modified Eagle medium mixed 1:1 with Ham F12 medium and a supplement of known amounts of 2 growth factors-bFGF (100 ng/mL) and IGF-I (100 ng/mL)-used in combination and separately. RESULTS: The combination of IGF-I and bFGF enhanced chondrocyte growth and maintained a high degree of viability in SFM and 10% fetal calf serum. After an initial lag, the SFM, augmented with both growth factors, produced a comparable number of viable cells (4.25+/-0.31 x 10(4)) to that of the medium with 10% fetal calf serum (4.64+/-0.35 x 10(4)) by the seventh day of the experiment. Combined with the 2 growth factors, 10% fetal calf serum provided the greatest proliferation by the end of the experiment. However, the overall mean cell counts for the IGF-I- and bFGF-enhanced SFM were not statistically different. CONCLUSIONS: The combination of IGF-I and bFGF in a serum-free and a serum-supplemented environment supports the growth and viability of human septal chondrocytes in short-term culture. In an SFM, the results obtained approximate those produced in a medium enhanced with 10% fetal calf serum.     

Production of chitinase by Actinomyces kurssanovii and its properties

Actinomyces kurssanovii, a culture producing large amounts of chitinase and chitobiase, was cultivated on a medium of the following composition (%): demineralized crab shells, 3.0; K2HPO4, 0.5; peptone, 0.2; yeast extract, 0.1; MgSO4-H2O, 0.09. The maximum amount of the enzymes was synthesized after growth in a fermenter of the actinomycete during 48 hours. The highest activity of chitinase is manifested at pH 7.0 and depends on ionic composition of the buffer, being higher in veronal buffer than in phosphate or tris//HC1 buffers. The chitinase and chitobiase of the strain decompose completely colloid chitin and chitin in demineralized crab shells with the formation of N-acetyl-D-glucosamine.     

In vitro viability of cryopreserved equine embryos following different freezing protocols

Aspergillus fumigatus grown in submerged and surface cultures was extracted, and the extracts were analyzed separately. The submerged extract contained 31.9% protein and 8.3% carbohydrate, while the corresponding values were 17.0% and 33.3% for the surface material. With individual sera from patients with allergic asthma, SDS-PAGE combined with immunoblotting revealed that the submerged extract contained at least six strong IgE-binding components (20, 30, 38, 50, 68, and 90 kDa) in addition to several weak to medium IgE-binding components. The surface extract contained about the same number of IgE-binding components, but only one gave a strong reaction (20 kDa). The allergens present were shown to have pI between 4.5 and 5.6 as demonstrated by isoelectric focusing (IEF) combined with immunoblotting. For identification of A. fumigatus glycoprotein allergens, both extracts were treated with periodate under mild conditions. Two allergens of the submerged extract (90 and 38 kDa) partly lost their IgE-binding ability by this treatment, indicating that these components are glycoproteins and that the carbohydrate moiety is involved in the IgE binding. The IgE-binding ability of the 20-kDa allergen was not influenced by periodate. For assessment of the stability of the two allergen extracts, aqueous solutions were kept at 4 degrees C for 2, 7, and 21 d and then analyzed by SDS-PAGE and immunoblotting. The results showed that most allergens of the submerged extract were partly inactivated after 2 d. After 21 d, only the 20-kDa and 30-kDa components were still able to bind IgE. Similar results were obtained by analyzing the surface extract.(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibition of growth and aflatoxin production of Aspergillus parasiticus by citrus oils

Aspergillus parasiticus was inoculated into grapefruit juice and a glucose-yeast extract medium; both contained 500-7000 ppm of citrus oils that were incorporated into the media by sonication. Orange and lemon oil were more inhibitory to mold growth and aflatoxin production than was dlimonene, the main constituent of the two peel oils. After 7 days at 28 degrees C, 2000 ppm of lemon and 3000 ppm of orange oil in grapefruit juice afforded maximum suppression of mold growth and toxin formation. When the glucose-yeast extract medium was used, 3000 ppm of either oil were needed to achieve the same result. After 4 days at 28 degrees C, orange oil at 3500 ppm in either medium markedly inhibited mold growth (as evidenced by dry weight of mold mycelium) and aflatoxin production (only 14 and 1% of the amount normally produced in the juice and artificial medium, respectively). Higher concentrations of orange oil further reduced mold growth and aflatoxin production and also delayed the onset of sporulation, if it occurred. Although aflatoxin was detected in all samples, only 0.2 to 0.5% of the amount found in controls (without the citrus oil) was present when the medium contained 7000 ppm orange oil. The mold consistently grew, albeit very poorly, on the glass at the liquid-atmosphere interface even when the substrate contained a large amount of citrus oil.     

Effect of luteinizing hormone on the pattern of steroid production by preovulatory follicles of pregnant mare's serum gonadotropin-injected immature rats

Preovulatory follicles were explanted on the day before ovulation from immature rats given a single injection of Pregnant Mare's Serum gonadotropin (PMS) 2 days earlier. The follicles were incubated for 4 h in modified Krebs bicarbonate buffer containing glucose and albumin in absence or presence of ovine luteinizing hormone (NIH-LH-S18; 0.1-10 mug/ml). The accumulation of progresterone, androstenedione and 17beta-estradiol in the medium was determined by radioimmunoassay. As in indicator of LH exposure the meiotic stage of the follicle-enclosed oocyte was determined at recovery by interference contrast microscopy. The first group of follicles were explanted in the morning, before the endogenous gonadotrophin surge. In hormone-free medium the oocytes remained in the dictyate stage, whereas addition of LH induced oocyte maturation. These follicles, when incubated in hormone-free medium, secreted predominantly androstenedione and estradiol and only low amounts of progesterone. In the presence of LH the secretion of all steroids was enhanced. The second group of follicles were explanted in the evening, 2-4 h after the endogenous gonadotrophin surge. After incubation in hormone-free medium the follicle-enclosed oocytes had matured. The steroid secretion by the follicles was different from that of the first group. In hormone-free medium they secreted predominantly progesterone and low amounts of androstenedione and estradiol. Addition of LH to the medium caused further enhancement of progesterone secretion, but had no effect on androstenedione and estradiol secretion. The third group of follicles were explanted in the evening from rats in which the preovulatory gonadotrophin surge had been prevented by Nembutal treatment. Oocyte maturation and steroid secretion did not differ from that found for the first group of follicles explanted in the morning. The results are compatible with the hypothesis that LH, after a transitory stimulation, inhibits androgen and estrogen secretion and stimulates progesterone secretion by the preovulatory ovarian follicle.