The Germicidal Effect of Staining Solutions

Gentian violet, crystal violet and carbol fuchsin applied to cover slip preparations for one minute will destroy the majority of non-spore-forming bacteria and yeasts, tho they can not be relied upon to do this consistently and in all cases.

The Gram staining procedure is more effective and non-spore-formers were never found to survive this process.

Methylene blue stains exert very little if any germicidal power and most organisms survived them readily. India ink was totally ineffective.

Several species of yeasts and yeast-like molds were killed in every instance by the Gram stain, gentian violet, crystal violet and carbol fuchsin, but survived both Loeffler's methylene blue and a plain aqueous solution of methylene blue.     

The Germicidal Effect of Staining Solutions

Gentian violet, crystal violet and carbol fuchsin applied to cover slip preparations for one minute will destroy the majority of non-spore-forming bacteria and yeasts, tho they can not be relied upon to do this consistently and in all cases.

The Gram staining procedure is more effective and non-spore-formers were never found to survive this process.

Methylene blue stains exert very little if any germicidal power and most organisms survived them readily. India ink was totally ineffective.

Several species of yeasts and yeast-like molds were killed in every instance by the Gram stain, gentian violet, crystal violet and carbol fuchsin, but survived both Loeffler's methylene blue and a plain aqueous solution of methylene blue.     

Differentiation of Nucleic Acids by Staining at Controlled pH and by A Schiff-Methylene Blue Sequence

Fixation with Bouin's fluid preserves cytoplasmic and nucleolar ribonucleic acid (UNA) particularly well. RNA may be demonstrated preferentially in Bouin fixed tissue by staining with 0.02% thiazine dye in aqueous McIIvaine phosphate-citrate buffer between pH 3 and 4. Methylation blockage of basophilia other than that of nucleic acids permits staining of RNA with thiazine dyes near neutrality. The deoxyribonucleic acid (DNA) of chromatin undergoes a Feulgen type hydrolysis in the tissue block during 24 hr fixation with Bouin's fluid. This hydrolysis by picric acid permits Schiff staining of the DNA wthout further acid hydrolysis. Consequently after Bouin fixation it is possible to demonstrate DNA and RNA specifically by a Schiff-methylene blue sequence. Thus a Schiff stain without further acid hydrolysis followed by 0.02% methylene blue in phosphate-citrate buffer at pH 3.0 to 3.5 colors DNA magenta in contrast to the blue of RNA.     

Staining Paraffin Sections with Protargol 3. The Optimum pH for Reduction. 4. A Two-Hour Staining Method

Further work on conditions affecting the reduction of paraffin sections impregnated with protargol showed that the optimum pH for sulfite-amidol mixtures was between 6.5 and 7.5. A staining method which requires about two hours to complete consists of the following steps: (1) One hour impregnation at 60° C. in 10% AgNO₃. (2) Wash in distilled water 3 changes of 30 sec. each. (3) Put into protargol (Winthrop Chem. Co., New York, N. Y.) 0.2% aq. for another hour at room temperature. (4) Rinse 2 sec. (5) Reduce one to two min. in amidol 0.2 g., Na₂SO₃ 8 g., NaHSO₃ I g., and water 100 cc. (6) Wash thoroly. (7) Tone with 0.1% gold chloride. (8) Wash. (9) Reduce with a 0.5% aq. soln. of amidol (no sulfite). (10) Wash, dehydrate and cover. The method stains neurofibrillae and unmyelinated fibers and has worked well on most tissues of vertebrates. The stain follows acid alcoholic fixation.     

The Effect of Ph on Silver Staining of Nucleolus Organizer Regions

The effect of pH on silver staining of the nucleolus organizer regions (NORs) of human chromosomes has been investigated between pH 6.5 and 12.0. Nonvolatile mixtures of ethanolamine and ethanolammonium nitrate replaced the ammonia of standard procedures. The optimal NOR staining obtained at pH 3.5 by the silver staining procedure of Howell and Black served as a standard; this procedure stained all ten NORs in 90% of mitoses. Similar NOR staining was found in 75% of mitoses stained at pH 11.7 or 11.8, but only in 10-15% of mitoses stained between pH 11.6 and 10.0. Between pH 10.0 and 9.0 NOR staining was incomplete, and between pH 8.5 and 6.5 there was no NOR staining.     

Effect of pH on aluminum-driven methanogenesis by Methanococcus thermolithotrophicus

Methanogenesis from various elemental metals as electron sources has been demonstrated before. In this study, we have examined the influence of pH on the methanogenic activity of Methanococcus thermolithotrophicus dependent on cathodic hydrogen produced by elemental aluminum wires. When grown on H₂+CO₂, M. thermolithotrophicus had an optimum pH of 6.2, but when all the H₂ was supplied from A1°, the pH optimum was 5.7, consistent with thermodynamic predictions. The results also indicated that aluminum is quite resistant to anaerobic corrosion when compared to iron, most likely due to adhesion of aluminum oxide or hydroxide layers on the surface of the wires. Correspondence to: R. Boopathy     

Effect of pH on Orthophosphate Uptake by Corn Roots

Orthophosphate (Pi) influx in washed corn roots was studied with experimental conditions allowing a distinction of pH effects on Pi ionization in the medium and on the transport system itself. There appeared to be no relationship between the pH dependencies of membrane potential, H⁺ secretion, and ³²Pi influx. The Pi uptake versus pH curves were compared to the calculated ones describing the concentrations of the different ionized Pi forms in the medium and in the cell walls; the latter were obtained using the theoretical model described by Sentenac and Grignon (1981) Plant Physiol 68: 415-419). The conclusion was that the transported form is H₂PO₄⁻ and the concentration sensed by the transport system is the local one. The ionic compositions of experimental media were manipulated to ensure constant pH and various H₂PO₄⁻ concentrations, or constant H₂PO₄⁻ concentration and various pH values in the walls. The kinetic analysis of the results in the micromolar range showed that the transport system has an intrinsic sensitivity to pH, and is switched from a low activity state at pH > 6 to a high activity one at pH < 4 (pH in the walls). This change could be triggered by the protonation of a group with pK 5.5.     

The History of Staining the Development of Cytological Staining

Perhaps no other period has contributed more to our knowledge of the cell than the period 1875-1895. During these years most fundamental cytological phenomena were seen and described. Mitosis, maturation and fertilization, the great cornerstones of cytology, were firmly laid by the remarkable researches of Flemming, Strasburger, Van Beneden, Oscar and Richard Hertwig, Boveri and many others. Upon these researches experimental cytology developed and the significance of the morphological phenomena to inheritance and development was pointed out by such masters as W. Roux, Weismann, O. Hertwig, Boveri and E. B. Wilson.     

The History of Staining the Development of Cytological Staining

Perhaps no other period has contributed more to our knowledge of the cell than the period 1875-1895. During these years most fundamental cytological phenomena were seen and described. Mitosis, maturation and fertilization, the great cornerstones of cytology, were firmly laid by the remarkable researches of Flemming, Strasburger, Van Beneden, Oscar and Richard Hertwig, Boveri and many others. Upon these researches experimental cytology developed and the significance of the morphological phenomena to inheritance and development was pointed out by such masters as W. Roux, Weismann, O. Hertwig, Boveri and E. B. Wilson.     

Metachromatic Reaction of Pancreatic B Cells to Toluidine Blue; Influence of pH on Staining

The granules of islet B cells show an intense β metachromasia when paraffin sections of pancreas fixed in Bouin's fluid or formalin are dipped for 1 min in a 0.1% aqueous solution of toluidine blue O₂ buffered to pH 6.0 with acetate or phosphate. This reaction provides a quick method for surveying the condition of B cells in experimental work. A weak staining is observable at pH 4.5 and becomes distinct at pH 5.5-6.0. Oxidation of sections (0.25% KMnO₄ in 0.5% H₂SO₄, for 1 min, recommended) prior to staining intensifies the metachomatic reaction conspicuously. The metachromatic substance could not be demonstrated after fixation in either ethanol or acetone. It corresponds to the aldehyde fuchsin-positive and pseudoisocyanin-metachromatic substance in its occurrence and distribution in the B cells, as shown by different physiological states of various animals, including fasted and glucose-administered guinea pigs. It is thought to be topographically coincident but not necessarily identical to insulin.     

pH影响淀粉酶活性的探究

学生在探究pH对淀粉酶活性的影响时．出现了实验结果与预期结果不一致的现象,由此探究pH对淀粉酶活性的影响。     

The History of Staining the Development of Bacteriological Staining Methods

The staining of bacteria is naturally of later origin than the use of dyes in histological work, as the systematic study of bacteria did not begin until after 1870. The use of dyes in this study followed very promptly after that date, however.     

The Staining of Radulae

A review of the various methods of staining and mounting radulae is given. Normally the radula should be extracted with 0.5 to 1% sodium hydroxide solution, and the associated tissues removed before staining. Two staining methods are recommended for facilitating the interpretation of radulae. Newly formed teeth and the bases of older ones are well stained by saturated aqueous chlorazol black E (up to 10 minutes). A more uniformly stained specimen) in which the cusps of all but the young teeth are alone stained, may be obtained by using the “oxidation-dahlia technic”. The radula is oxidized in N/10 potassium permanganate solution until black and subsequently decolorized in saturated aqueous oxalic acid. It is then stained in 0.1% aqueous dahlia (Hofmann's violet), the staining time varying from 10 to 30 minutes, according to the material. It is then dehydrated and passed through xylene and clove oil into Canada balsam. Other mountants may be employed but glycerin jelly is only recommended for the rapid examination of unstained radulae. Several other staining methods are mentioned, and general precautions to be observed while mounting are discussed.     

蛋白负染方法在蛋白质组学中的应用评价

为评价蛋白质负染方法在蛋白质组学分析中的应用,采用负染和考马斯亮蓝染色两种方法对同一样品的双向电泳胶进行染色,取相对应的8对蛋白点,并进行胶内酶解及MALDI-TOF/TOF分析,比较两种方法与质谱的兼容性。图像分析显示,负染方法展示出的蛋白点更多,但三维峰图不如考染明晰;质谱结果显示,8个负染蛋白点中有7个鉴定结果有效,8个考染蛋白点鉴定结果均有效。因此可以得出以下结论:负染的灵敏度高于考染,与质谱的兼容性良好,适用于建立双向电泳参考图谱的研究;但负染后的胶图不适于进行蛋白点丰度对比分析。     

Effect of pH on nickel biosorption by aerobic granular sludge

The Ni2+ biosorption by aerobic granular sludge was studied at various initial pH values of 2-7. Results showed that the initial pH would play an important role in the Ni2+ removal by aerobic granules and affected the zeta potential of aerobic granules. A thermodynamic equilibrium isotherm previously developed can fit the experimental data very well at all studied pH values. The close relationship between the zeta potential and Ni2+ biosorption capacity of aerobic granules showed the electrostatic attraction between the aerobic granules and Ni2+ ions. It was also found that some light metals, such as K+, Mg2+ and Ca2+ would be released into the bulk solution during the Ni2+ uptake onto the aerobic granules, which in turn indicated that ion-exchange was one of the Ni2+ biosorption mechanisms.     

Effect of low pH on thiomethyl-beta-D-galactoside uptake by Streptococcus lactis

Maximal beta-galactosidase activity in Streptococcus lactis was obtained at pH 7, but the maximal rate of thiomethyl-beta-d-galactoside uptake was observed at pH 3.6 to 4. It is concluded that the decrease in beta-galactosidase activity in intact cells at lowered pH is not due to diminished transport of beta-galactoside.