Postharvest behaviour of five Sardinian prune varieties as affected by immersion in heated sodium bicarbonate solution

Storage behaviour of 'Core', 'Core Columbu', 'Fradis' and 'Meloni' white prunes, and a black one ('Sighera') of Sardinian germplasm were evaluated following immersion for 0 (control), 15, 30, 45 or 60 sec in water at 20, 50, 55 or 60 degrees C with or without 2% (w/v) NaHCO3 (SBC). As international varieties, fruit from one white plum ('Shiro') and one black prune ('Stanly') were subjected to the same treatments. Fruit was harvested at commercial maturity, treated and then stored for 1 month at 5 degrees C and 90% RH followed by a simulated marketing period at 20 degrees C and 80% RH for 6 days. Fruit appearance, external damage, firmness and decay percentage were monitored after storage and SMP. Treatments did not induce rind damage (browning or discoloration) to any variety. SBC at 20, 45, 50 or 55 degrees C for 15 or 30 sec was not effective in controlling decay and compared to controls no improvement was observed. Immersion for 45 or 60 sec with SBC at all temperatures improved decay control with respect to controls and best results were obtained at 50 or 55 degrees C. Immersions at 60 degrees C improved decay control, but differences were not significant compared to the control attained with solutions of SBC heated at 55 degrees C. The overall appearance of 'Core', 'Core Columbu', 'Fradis' and 'Shiro' decreased significantly after the SMP period, especially when treated at 55 or 60 degrees C for 60 sec. Fruit shrivel was the main cause of the low rating. SBC did not affect shrivel indicating that heat treatment may be the probable cause. In general, local varieties were less affected by decay than other varieties and they performed well during storage.     

Effect of the physical properties of acrylic resin of overnight immersion in sodium hypochlorite solution

doi:10.1111/j.1741‐2358.2009.00336.x
Effect of the physical properties of acrylic resin of overnight immersion in sodium hypochlorite solution Objectives: This study evaluated colour stability, surface roughness and flexural strength of microwave‐polymerised acrylic resin after overnight immersion in sodium hypochlorite, simulating 180 days use. Materials and methods: Forty disc‐shaped (15 mm × 4 mm) and 40 rectangular specimens (65 mm × 10 mm × 3 mm) were prepared from microwave‐polymerised acrylic resin. The specimens were immersed in 0.5, 1% sodium hypochlorite, Clorox/Calgon and distilled water. Colour measurements (ΔE) were determined by a portable colorimeter. A surface analyser was used to measure roughness (μm). The flexural strength (MPa) was measured using a three‐point bending test in a universal testing machine. Data were evaluated by one‐way anova , followed by Student–Newman–Keuls test (α = 0.05). Results: Statistical analysis found significantly higher colour changes (SNK, p < 0.001) for the 1% sodium hypochlorite, but mean ΔE value quantified by National Bureau of Standards was classified as slight. When comparing the surface roughness, no statistical significance was found among the solutions (anova , p = 0.637). The 1% sodium hypochlorite presented significantly lower flexural strength compared with the control group (SNK, p = 0.034). Conclusion: It was concluded that immersion in 1% sodium hypochlorite solutions for 8 h does influence the colour stability and flexural strength of microwave‐polymerised acrylic resin, during the simulated period of 180 days.     

Habituation in Nicotiana bigelovii tissue cultures: Different behaviour of two varieties

The exceptionally high capacity for transformation to autotrophyfor hormones (habituation) discovered in Nicotiana bigeloviiled us to a comparison of the responses of 2 varieties (quadrivalvisand bigelovii) to different hormone treatments applied to theirseeds. Hormones used were: kinetin (0.8, 1.6, 3.2 ppm), 2,4-D(0.1, 0.4 ppm), IAA (2 ppm) and NAA (1, 2, 4 ppm). Callus formation and habituation were scored after transferon minimal medium (without hormones) 3 months after sowing.Var. quadrivalvis showed a much higher ability to form callusbut the callus formed was autonomous in a lower percentage ofcases when IAA or kinetin treatment was considered. Analysisof auxin-like substances in leaves of the 2 varieties showeda higher content in N. bigelovii var. quadrivalvis. Data arediscussed with particular regard to their relevance to tumorousphenomena in plants. ¹ Publication No 52 of the Laboratorio di Mutagenesi e Differenziamento,C. N. R. (Received March 30, 1971; )     

Effects of temperature and daminozide on the induction of ethylene synthesis in two varieties of apple

Factors affecting the induction of ethylene synthesis in apple were investigated through their effect on the delay in ethylene production (DEP) in single fruits after harvest. DEP in Cox apples was not affected by temperature from 1 to 25°C, but in Golden Delicious, DEP was shorter below 12°C and above 20°C. An orchard treatment with daminozide increased DEP in apples held below 15°C or treated with ethylene after harvest. Experiments in which the temperature was changed after ethylene treatment showed that ethylene was less active at 5°C than at 15°C but that response to it could be equally rapid. The results suggest that endogenous ethylene is not regulatory prior to the onset of rapid ethylene synthesis.     

Dissociation and denaturation behaviour of sesame alpha-globulin in sodium dodecyl sulphate solution.

The effect of anionic detergent, sodium dodecyl sulphate, on the major protein, alpha-globulin of sesame seed (Sesamum indicum L.) has been investigated by gel filtration, sedimentation velocity, viscosity, optical rotation, difference spectra and fluorescence measurements. The detergent causes dissociation of the protein first and then denaturation. In the detergent concentration range of .175-4.0 X 10(-"3) M four components are observed in the ultracentrifuge. The specific rotation of the protein increases with the detergent concentration above 2.5 x 10 (-3) M detergent suggesting conformational change; above 8 X 10(-"3) M detergent the value of -[alpha] does not change. The reduced viscosity etared however, increases above .25 X 10(-3) M detergent and does not attain a plateau value. The difference spectrum of the protein indicates that both tryptophan and tyrosine groups have been affected by the detergent. The fluorescence intensity decreases and the maxima shifts towards red in the detergent solution resulting in an "isoemissive point" at 355 nm. The double difference spectra in sucrose-detergent protein system show that below 5-0 X 10(-3) M detergent, the difference absorption and fluorescence spectrum result from the binding of the detergent near the chromophoric groups and are not due to conformational change. Binding studies by equilibrium dialysis indicate the presence of 50 binding sites in the protein and binding constant of 3-0 X 10(3).     

Bacterial endophyte communities of two wheatgrass varieties following propagation in different growing media

Bacterial endophyte communities of two wheatgrass varieties currently being used in the revegetation of military training ranges were studied. Culturable and direct 16S rDNA PCR amplification techniques were used to describe bacterial communities present in Siberian and slender wheatgrass seeds, leaf tissues, and root tissues following propagation in either sand or a peat-based growing mix. Our hypothesis was that the resulting plant endophytic communities would be distinct, showing not only the presence of endophytes originating from the seed but also the characteristics of growth in the two different growing media. Both culture and culture-independent assays showed the likely translocation of Actinobacteria, Firmicutes, and Gammaproteobacteria from seed to mature plant tissues as well as subsequent colonization by exogenous organisms. Statistical analysis of 16S terminal restriction fragment profiles identified growing media as having a greater significant effect on the formation of the endpoint endophytic communities than either plant tissue or wheatgrass variety. In silico digests of the ribosomal database produced putative identifications indicating an increase in overall species diversity and increased relative abundances of Firmicutes and Cyanobacteria following propagation in sand and Betaproteobacteria following propagation in the peat-based growing mix. Results indicated a substantial translocation of endophytes from seed to mature plant tissues for both growing media and that growing medium was a dominant determinant of the final taxonomy of the endpoint plant endophytic communities.     

Responses of two varieties of tomato to abrupt and gradual short-period sodium chloride exposure

Summary The relationship between osmotic adjustment and mineral retention by different plant parts were examined for two varieties of tomato (Lycopersicum esculentum L): Pritchard and Rogygross.Plants were grown in solution cultures and exposed at each stage of development either gradually to 0.05M NaCl increments for 6 hours each until 0.20M, or abruptly to increased NaCl levels for 24 hours.Both varieties of tomato survived gradual exposure to NaCl increments at all stages of development, while unable to survive abrupt exposure to 0.20M, and even Pritchard to 0.15M NaCl during the vegetative stage. With abrupt exposure to 0.15M and 0.20M NaCl both varieties showedi nitial wilting followed by rapid recovery during flowering.Although Pritchard showed lower tolerance with abrupt exposure it exhibited similar osmotic adjustment as Rogygross variety upon the gradual exposure to NaCl increments.Increased NaCl concentration in the root medium induced a gradual uptake of Na with a concomitant partial replacement of K, which was associated with increased Ca retention in the aerial parts. Gradual exposure increased the retention of the osmoregulatory cations K and Ca.It was suggested that gradual rather than abrupt changes in the internal osmotic pressure, which was associated with the increased retention of osmoregulatory cations, being itself not restrictive for essential metabolic processes.     

Effect of sodium bicarbonate supplementation on two different performance indicators in sports: a systematic review with meta-analysis

[Purpose]Sodium bicarbonate shows ergogenic potential in physical exercise and sports activities, although there is no strong evidence which performance markers show the greatest benefit from this supplement. This study evaluated the effects of sodium bicarbonate supplementation on time trial performance and time to exhaustion in athletes and sports practitioners.[Methods]A systematic review was conducted using three databases, including 17 clinical trials. Among these clinical trials, 11 were considered eligible for the meta-analysis according to the criteria for the assessment of methodological quality using the PEDro Scale. Time to exhaustion was assessed in six studies, while time trial performance was evaluated in five studies.[Results]A significant beneficial effect of supplementation on time to exhaustion was found in a random effects model (1.48; 95% confidence interval [CI], 0.49 to 2.48). There was no significant effect of supplementation on time trial performance in a fixed effects model (slope = −0.75; 95% CI, −2.04 to 0.55) relative to a placebo group.[Conclusion]Sodium bicarbonate has the potential to improve sports performance in general, especially in terms of time to exhaustion.     

Effects of sodium chloride and sodium bicarbonate in the diet on the performance of calves

Sixty male Friesian calves were weaned from milk at 5 weeks of age. From 3 to 11 weeks of age, the calves were offered a diet of barley, meat meal, urea and 15% oat straw, supplemented with sodium chloride (NaCl) or sodium bicarbonate (NaHCO₃). The sodium (Na) contents of the diets supplemented with NaCl were 0.3, 1.1, 1.9 and 2.8%. The sodium contents of the diets supplemented with NaHCO₃ were 1.1 and 1.9%.The performance of the calves fed on the diets containing 0.3, 1.1 and 1.9% Na from NaCl was similar, but the organic matter intake and weight gains of the calves fed on the diet containing 2.8% Na were significantly lower between 5 and 11 weeks of age. The feed intake of the calves fed on the diets containing 1.1 and 1.9% Na from NaHCO₃ was 8 and 15% greater than the feed intake of the calves fed on the diet containing 0.3% Na. However, there was no significant difference in the intake of organic matter, the efficiency of feed conversion ratios or the weight gains of the calves.The sodium treatments resulted in no significant differences in the concentration of volatile fatty acids in the rumen. The addition of NaHCO₃ to the diets altered in acid—base balance in jugular blood.     

Effect of amino acids on aggregation behaviour of sodium deoxycholate in solution: a fluorescence study

The influence of three alkaline amino acids, l ‐lysine (L ‐Lys), l ‐arginine (L ‐Arg) and l ‐histidine (L‐His), on the aggregation behaviour of sodium deoxycholate (NaDC) in phosphate buffer, pH 7.0, was studied at 25 °C. The fluorescence probe technique based on pyrene was employed to determine accurately the critical aggregation concentration (cac), polarity of the microenvironment and aggregation numbers for the NaDC aggregates. The added amino acids can effectively reduce the cac values and micropolarity of NaDC, indicating that it is easier for NaDC to aggregate in a compact manner in the presence of amino acids. The aggregation numbers of NaDC were increased, indicating that more NaDC molecules connect together to form stable aggregates. The performance of L‐Arg is similar to that of L‐His, and both have a smaller effect on the above parameters than L ‐Lys. In view of this, it may be inferred that both electrostatic and hydrophobic interaction are responsible for the interaction between NaDC and amino acids in aqueous solution. Copyright © 2011 John Wiley & Sons, Ltd.     

The sodium and bicarbonate dependence of bile secretion in the guinea-pig

The effects of the total substitution of sodium by lithium, and of bicarbonate by a mixture of chloride and phosphate, on the flow and composition of bile was studied in the isolated perfused guinea-pig liver using a single-pass perfusion system. 60% of secretion was bicarbonate dependent and 80% specifically required the presence of sodium. The secretion of bicarbonate in bile against a concentration gradient was inhibited by the presence of lithium. In contrast to the results of similar studies in the rat, lithium is not an effective substitute for sodium in maintaining bile secretion.     

Accumulation of bicarbonate in intact chloroplasts following a pH gradient

With silicone layer filtering centrifugation the uptake of radioactively labelled bicarbonate into isolated spinach chloroplasts was followed. This uptake was shown to have the following properties:

1. (a) It is so rapid that the kinetics of uptake usually cannot be resolved.

2. (b) Bicarbonate is accumulated in the stroma. The factor between the internal and external concentrations increases greatly when the pH of the medium is lowered from pH 8.5 to pH 7.0.

3. (c) The accumulation factor is independent of the concentration in the medium for a long concentration range.

4. (d) The accumulation of bicarbonate is increased when the chloroplasts are illuminated. This increase is abolished by the addition of uncoupler.

5. (e) Diamox, an inhibitor of carbonic anhydrase, inhibits the rate of bicarbonate uptake.

The activity of carbonic anhydrase was assayed in isolated chloroplasts and in leaf homogenates. In agreement with earlier reports the main activity was found to be located in the chloroplasts. This activity is latent; it can be only assayed if the chloroplasts are osmotically shocked.

From these results the following conclusions have been drawn:

1. (a) The inner membrane is impermeable to protons. Light-driven proton transport into the thylakoid space causes an alkalisation of the stroma.

2. (b) The uptake of bicarbonate proceeds via diffusion of CO₂ across the inner membrane. There are no indications for a specific transport of bicarbonate.

3. (c) The CO₂ concentration in the chloroplasts may be equal to the CO₂ concentration in the external space. The distribution of bicarbonate between the two compartments is inversely proportional to the distribution of protons.

A possible involvement of carbonic anhydrase and the bicarbonate pool in the stroma in increasing the CO₂ affinity of CO₂ fixation is discussed.     

不同品种苹果树内生细菌群落多样性及功能

【背景】目前苹果树内生细菌的研究较多,但对不同品种苹果树内生细菌群落多样性分析比较的相关报道还较少。【目的】通过分析比较新疆本地和吉尔吉斯斯坦引进的8个不同品种苹果树内生细菌群落多样性的差异,可以充分挖掘其蕴含的丰富微生物资源。【方法】采用MiSeq高通量测序技术分别测定不同品种苹果树内生细菌群落16S rRNA基因V3-V4区序列并进行生物信息学分析。【结果】不同品种苹果树中获得的V3-V4区有效序列数在61487-71583条之间,聚成24-92个操作分类单元(operationaltaxonomicunit,OTU),Shannon指数和Simpson指数分别在0.729-1.177和0.265-0.457之间,新疆本地品种的苹果树内生细菌种类和多样性高于吉尔吉斯斯坦品种。内生细菌种群分析结果表明,变形菌门和放线菌门的OTU总计分别覆盖了不同品种苹果树内生细菌的61.16%-97.08%,为苹果树的主要优势细菌门。优势细菌属数目、组成及其丰度随苹果品种的不同而有所差异。马赛菌属(Massilia)和节杆菌属(Arthrobacter)的总丰度最高,其丰度分别在6.06%-71.3...     

Dielectric behaviour of frozen DNA in solution

In this article, measurements are reported on ice and frozen DNA solutions between 100 Hz–10 MHz. Pure ice is shown to exhibit single relaxation behaviour, which confirms previous work taken over a more restricted frequency range. The frozen DNA solution displays double‐dispersion behaviour. One dispersion centred around 3 kHz is due to a defect mechanism while the other, centred around 2 MHz, may be attributed to counterion flow through the water immediately adjacent to the DNA molecule. Bioelectromagnetics 20:40–45, 1999. © 1999 Wiley‐Liss, Inc.     

Fate of fluorescent microspheres in developing Ictalurus punctatus following prolonged immersion

Particulate antigen uptake by the mucosa of developing channel catfish was determined by immersing larvae and fry [2-day post-hatch (dph), 1-, 2-, 3-, 4-, and 8-week post-hatch (wph)] to two forms of fluorescent microspheres (FMS): blue FMS were carboxylated, and green FMS were coated via conjugation with a crude extract of Edwardsiella ictaluri outer membrane protein (OMP). Phagocytosis, destination, and clearance appeared similar for the two types of FMS used. In the older age classes, primary uptake was observed in epithelial cells of the torso, fins, nares and to a lesser extent the gills. Fluorescent microspheres were less frequently observed within mononuclear phagocytes in the epidermis, dermis and underlying connective tissue of the tissue mentioned above. Limited FMS trafficking was observed from 4- to 24-h post-immersion (hpi). Significantly higher numbers of FMS (blue and green)/mm(3) of tissue were observed in the posterior kidney of the 4- and 8-wph age classes and in the anterior kidney and spleen of the 8-wph age class when compared to younger age classes (p < 0.05). Significantly higher FMS (blue and green)/mm(3) of tissue were observed in the posterior kidney of 4- and 8-wph fish when compared to all other organs (p < 0.05). The present study indicates that FMS uptake increases with age in channel catfish. The younger age classes may possess an increased ability to exclude particulate antigen, or lack the specific mechanisms that needed to take up particulates in the form of FMS.     

Viscosity behaviour and persistence length of sodium xanthan in aqueous sodium chloride

Zero-shear-rate intrinsic viscosities [eta] of sodium xanthan in aqueous NACl at 25 degrees C were determined for five samples ranging in weight- average molecular weight from 2 x 10(5) to 4 x 10(6) at salt concentrations Cs between 0.005 and 1 M, at which the polysaccharide maintains its double-helical structure. The measured [eta] for every sample was almost independent of Cs, in contrast to usual observations on flexible polyelectrolytes. The persistence length q of sodium xanthan was determined as a function of Cs by use of the theory of Yamakawa et al. for [eta] of an unperturbed worm-like cylinder, and from its Cs dependence the intrinsic persistence length q(o) ( = q at infinite ionic strength) was estimated to be 106 nm. This q(o) value was roughly twice as large as that of double-stranded DNA, indicating a high intrinsic rigidity of the xanthan double helix. The electrostatic contribution ( = q - q(o)) to q was only about 10% even at the lowest Cs of 0.005 M. Thus, it was concluded that above Cs = 0.005 M, the double- helical structure of sodium xanthan is hardly stiffened by electrostatic interactions between charged groups.