Sealed Jars Research Articles

D-rice seedling development in periodically stirred water in sealed environments

Summary Large numbers of germinating seedlings of two rice cultivars exhibited d- type development consisting solely of completely white coleoptile growth after 15 days in the light in both static and periodically stirred water environments in completely sealed jars. Thus, whether germinated in static or agitated water in the sealed environments, coleoptile greening and subsequent normal seedling development were inhibited by hypoxic stress caused by the large numbers of germinating rice seedlings competing for the limited environmental oxygen supply. Consequently, the evidence presented points away from the formation of unfavourable oxygen diffusion gradients in static water environments in the sealed jars as having been responsible for d type seedling development observed in previous investigations. Continuous aeration of the 15-day-old static and periodically stirred aquatic environments, respectively, resulted in complete reversal of all d seedlings into normal green plants.

Importance of the rate of hydration of pharmaceutical preparations of guar gum; a new in vitro monitoring method.

Dietary supplements of guar gum are known to improve blood glucose control in diabetic patients. The efficacy of guar is probably dependent mainly upon its capacity to hydrate rapidly and thus to increase viscosity in the small intestine post-prandially. Measurement of the rate of hydration in vitro might therefore be a useful index of the effectiveness of guar formulations. A simple method for monitoring the hydration rate of guar gum has been developed, which involves measuring the changes in viscosity at discrete time intervals over a period of 5 h using a Brookfield RVT rotoviscometer. Six different samples of guar gum (four pharmaceutical preparations and two food grades of guar flour) were hydrated in sealed glass jars rotated at 6 rev min-1 in order to prevent particle aggregation. Marked differences in hydration rate and ultimate (maximum) viscosity between the different guar samples were observed. Three of the four pharmaceutical preparations were lower in viscosity than the food grades of guar flour during the first 60 min of hydration. Two of the preparations hydrated so slowly that even after 5 h they attained viscosity levels of only 60% of their ultimate viscosity. These results may explain why some guar gum preparations are clinically ineffective.

Ensiling whole wheat for ruminant feeding at different stages of maturity

Wheat at three different maturation stages — early milk, milk and dough ripening — was ensiled in 1.5-1 sealed glass jars for 30 days. Chemical and microbiological changes in the silages were followed. At the end of the ensiling period, the silages were subjected to an aerobic stability test. In addition, fibre analysis was obtained throughout the growth period of the wheat. The best silages were obtained from the wheat harvested at the milk and dough ripening stages. In the silage of the milk stage, the pH decreased more rapidly and to lower values. The water-soluble carbohydrate (WSC) content decreased from 10% in dry matter (DM) in the early milk stage to 3.2% in the dough ripening stage. However, lactic acid was formed in sufficient quantities (⩾ 10% in DM) in the silages prepared from the wheat of all three stages of maturity. The silages from the early milk stage contained more ethanol and butyric acid, which reflected higher yeast and clostridial counts, respectively. Silages from all three harvests were stable under aerobic conditions. Fibre analysis revealed that percent acid detergent fibre (%ADF) and cellulose decreased in the milk stage compared to early milk. Total fibre content (percent neutral detergent fibre (%NDF)) decreased in the dough ripening stage compared to the milk stage. The hemicellulose content did not change consistently throughout the growth period of the wheat and was ∼ 20% in DM. The crude protein content decreased from 23.7 to 9.0% in DM during the development of the wheat.

Headspace Gas Composition and Chitin Content as Measures of Rhizopus stolonifer Growth

ABSTRACTRelationship was determined between CO2 and O2 headspace concentrations and growth of Rhizopus stolonifer on potato dextrose agar in sealed jars. Changes in gas composition were typical of microbial growth curves. A 2‐day lag period was followed by a 3.5‐day rapidly changing period (exponential growth) and leveling off. No further change was observed when O2 was reduced to about 2%. A linear relationship was found between chitin (as glucosamine) formation and O2 (r2= 0.96) and CO2 (r2= 0.90) concentrations in headspace. Gas analysis (as measured by coefficient of variation) was more precise than chitin analysis. In air‐tight pure cultures, headspace gas analysis was an acceptable measure of mold growth with advantages of being nondestructive, simple, accurate, and rapid.

Partitioning of Lindane between sediment, water and the Crustacean Metapenaeus macleayi

The partitioning behaviour of lindane between sediment, water and the prawn Metapenaeus macleayi was investigated. The sediment-to-water partition coefficient was determined with sealed glass vials in laboratory experiments and found to be 9.52, or 2164 on an organic carbon basis. This is in agreement with relevant literature data and confirms that the organic matter of the sediment is the primary sorption site in this process. The bioconcentration factor was evaluated from laboratory experiments with prawns in sealed glass jars in which the lindane seawater solution was changed frequently. Under these conditions, effective equilibrium was attained after 24 h. Measured uptake (k1) and clearance (k2) rate constants were smaller than predicted on the basis of existing general relationships between k1, k2 and the octanol/water partition coefficient (Kow) for crustaceans. The bioconcentration factor (KB) was found to be 5.50, or 1273 on a lipid basis, which is also smaller than values estimated from general relationships. The sediment-to-prawn bioaccumulation factor was 0.58, which means that biotic concentrations will be significantly less than those observed in sediments.

Circadian rhythm of oxygen consumption and oxygen levels in the muscle of Notothenia neglecta (Pisces, Teleostei)

1. The oxygen consumption of Notolhenia neglecta (Pisces, Teleostei) was measured during the Antarctic summer (16hr light and 8 hr twilight), in a sealed jar system. 2. Specimens of 917.5 g mean weight and of 34.2 cm mean standard length were used. 3. The oxygen levels in the muscle were continuously recorded by means of an oxygen microelectrode. 4. The behavior was observed by direct monitoring. 5. Different times were chosen for the measurements during the 24 hr of the day, at the temperature of 0°C. 6. The oxygen consumption was more or less constant during the morning, with a decrease in the late afternoon, corresponding to the highest point of the oxygen level in the muscle, to a marked decrease in activity. 7. At 8 a.m., another peak in the muscle oxygen level was observed, as well as the highest swimming activity and the highest susceptibility to gradual anoxia. 8. The values of respiratory frequency did not show a marked rhythmical variation. 9. Oxygen consumption, but mainly muscle oxygen levels and swimming activity, seem to have a circadian rhythm, as similar shaped curves repeated at different days and for different individuals.

Ethylene-associated phase change from juvenile to mature phenotype of daylily (Hemerocallis) in vitro.

Hemerocallis plantlets maintained in vitro for extended periods of time in tightly closed culture vessels frequently show a phenotype, albeit on a miniaturized scale, typical of more mature, field-grown plants. The positive relationship of elevated ethylene in the headspace of such vessels to the phase shift from juvenile to mature form is established. Rigorous restriction in air exchange with the external environment by means of silicone grease seals hastens the phase change and improves uniformity of response. Although some plantlets may take longer to accumulate enough ethylene in sealed jars to undergo change, added ethylene and ethylene-releasing agents promote it. Ethylene adsorbants (e.g. mercuric perchlorate) block the shift of juvenile to mature form. Critical ambient ethylene level for the shift is ca 1 microliter l-1. Levels up to 1000 microliters l-1 do not hasten the response but are not toxic. The phase change is fully reversible when air exchange permits ethylene to drop below 1 microliter l-1. At least 1 microliter l-1 ethylene is required to sustain the mature phenotype. The ethylene synthesis inhibitor aminoethoxyvinylglycine (AVG) prevents the phase change, while the ethylene biosynthesis intermediate 1-aminocyclopropanecarboxylic acid (ACC) improves it. KOH, as a CO2 absorbent, does not prevent the phase change. Histology sections demonstrate subtle changes in the form of shoot tips of plantlets undergoing phase change.

Ineffectiveness of ethylene biosynthetic and action inhibitors in phenotypically reverting theEpinastic mutant of Tomato (Lycopersicon esculentum mill.)

Five-day-old, dark-grown seedlings of theEpinastic (Epi) tomato mutant (Lycopersicon esculentum Mill.) and its parent, cultivar VFN8, were used as a system for assessing the role of ethylene in theEpi phenotype. The distinguishing features ofEpi seedlings are an increase in hypocotyl diameter and reduced hypocotyl length. Treatment of VFN8 seedlings with 0.5 μl/liter ethylene closely mimicked theEpi phenotype. The rate of ethylene production by 5-day-old, dark-grownEpi seedlings was double that of VFN8 seedlings. Nevertheless, treatment ofEpi seedlings with inhibitors of ethylene biosynthesis (aminoethoxyvinylglycine or Co2+) or ethylene action (silver thiosulfate or norbornadiene) failed to normalize theEpi phenotype.Epi seedlings grown in sealed jars containing ethylene and CO2 adsorbants also expressed the characteristicEpi phenotype. The results indicate that the physiological lesion resulting from theEpi gene mutation is not simply an overproduction of ethylene.

Free and Hydrolytically Released Formaldehyde from DMDHEU-Finished Cotton Fabric

The AATCC Sealed Jar test (Method 112) uses accelerated storage conditions to determine formaldehyde released from finished fabrics. A modification of the incu bation conditions of this test has been investigated in an attempt to provide a better measure of the free formaldehyde in fabric. By incubating test specimens at 20°C instead of at 49°C as in the standard test, there is less hydrolytic degradation of the finish. These modified conditions release 90% or more of the free formaldehyde from the test specimen but minimize the contribution of hydrolytically released formal dehyde from finish degradation due to incubation conditions of the test. Reproducibility of determinations was good. Typical results from DMDHEU-finished cottons in the modified and standard tests are presented. Sequential use of the tests in various com binations provides additional insight into free and easily released formaldehyde as well as that more difficult to release.

Effects of Delayed Cooling and Delayed Low-ethylene CA Storage on the Keeping Quality of ‘McIntosh’ Apples

Abstract ‘McIntosh’ apples (Malus domestica Borkh.) from trees field-sprayed with daminozide were kept in unstoppered 19-liter jars in air at 3.3°C for various periods of time before being sealed and exposed to low-ethylene controlled atmosphere (CA). Similar apples were kept in sealed jars with flow-through low-ethylene CA at 20° for various periods of time before being cooled to 3.3°. After the prestorage treatments of delayed establishment of low-ethylene CA storage (delayed CA) or delayed cooling, these apples were stored in the same jars with a flow-through simulated low-ethylene CA (2.5-3% O2, 3% CO2, <1 μl·liter−1 ethylene, 2.2°-3.3°) for 7.5 months. Delayed cooling or delayed CA for one to 4 days had little adverse effect on the keeping quality of the apples. Delayed cooling for 5 days or delayed CA for 5 to 7 days caused slight decreases in fruit firmness and acidity after storage and sometimes caused slight increases in ethylene production of the apples during storage. Delayed cooling for 7 to 11 days or delayed CA for 9 to 11 days often caused significant decreases in firmness and acidity and large increases in ethylene production. The adverse effect of extended periods of delayed cooling was greater than that of delayed CA. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide).

Clinical cryobiology of tissues: Preservation of corneas

It is well recognized that the clarity of the cornea is a function of its hydration, and that this hydration is controlled by a “pump-and-leak” mechanism operating across the posterior monolayer of cells called the endothelium. A breakdown of the endothelium through disease or injury causes a marked increase in corneal thickness as the stroma imbibes fluid from the aqueous humor in the anterior chamber of the eye. This thickened, edematous condition of the stroma results in a cloudy cornea with an associated marked decrease in visual acuity. Treatment for this condition is usually by full-thickness corneal transplantation (penetrating keratoplasty), the success of which is dependent upon the donor cornea having an intact and healthy endothelium. It is essential, therefore, that any method of corneal storage for penetrating keratoplasty should protect and preserve the endothelium in a viable state. Current clinical practice relies upon short-term methods of preservation by two principal methods. Moist Chamber Storage is the time-honored corneal preservation method; it consists of keeping enucleated eyes at 0–4 °C in a sealed jar containing a pad of cotton gauze soaked in saline to provide a humid environment. The time limit placed upon this method of storage is 24–48 hr after which the viability of the endothelium deteriorates rapidly. Storage in M-K (McCarey-Kaufman) Medium involves excision of the corneoscleral segment from the donor eye and immersing it, endothelial side uppermost, in a medium consisting of tissue culture medium, 5% Dextran 40, and antibiotics. Laboratory and clinical studies indicate that storage in M-K medium at 4 °C preserves human endothelial cells for up to 4 days when the eye has been removed from the cadaver in less than 10 hr postmortem. Long-term preservation of corneas by freezing has long been a major goal in eye banking because indefinite storage by cryopreservation offers significant advantages for the quality and the quantity of material for use in keratoplasty, as well as for its distribution. However, procedures that have been developed for the cryopreservation of corneas have not been widely used, and a number of studies have shown that these procedures are inadequate for maintaining the integrity of the corneal endothelium. Not surprisingly, clinicians are now reluctant to accept corneas that have been frozen by these methods, though the clinical need is now greater than ever. Current research aims to develop improved methods of corneal cryopreservation, and there is good reason to anticipate that improved methods will be available for clinical trial in the next several years.

PROTEOLYSIS AND FERMENTATION OF GRAIN-CORN ENSILED AT SEVERAL MOISTURE LEVELS AND UNDER SEVERAL SIMULATED STORAGE METHODS

Proteolysis of ensiled grain corn (Zea mays L.) was studied in both whole-kernel and ground forms at initial grain moisture levels ranging from 22 to 36%. Three trials simulated and examined the effects of anaerobic fermentation, aerobic pre-ensiling and aerobic postensiling environments on soluble nitrogen (SN) formation (Trials 1, 2 and 3, respectively). Sealed mason jars (1.2 L) with fermentation locks, polyethylene-lined metal pails (23 L) and polyethylene-lined metal pails with fermentation locks were used as storage containers in Trials 1, 2 and 3, respectively. Soluble nitrogen as a percent of total nitrogen (TN) increased substantially during anaerobic fermentation (0–90 d), but increased only slightly and not at all during aerobic storage pre-ensiling (0–5 d) and postensiling (0–8 d). As moisture level increased, rates and extent of fermentation and proteolysis increased in both whole and ground grain (Trial 1). Soluble nitrogen contents after 90 d of sealed storage were approximately double for ensiled corn above compared to below 30% moisture. Grinding increased the rate but not the extent of proteolysis at grain moisture levels above 30%; grinding had little effect on SN formation or fermentation parameters at lower moisture percentages. A fourth trial compared the effect of three low-rate organic acid treatments to ground and sealed corn and an unsealed 1.5% (wt/wt) acetic:propionic acid (20:80) treatment on whole kernels for proteolysis in grain corn at 28% moisture. Only a 0.2% (wt/wt) acetic:propionic:formic acid:formaldehyde (10:40:20:30) treatment partially inhibited proteolysis; it did not control mold growth. A 1.5% acetic propionic acid treatment inhibited fermentation, but produced SN contents similar to the ensiled control. Key words: Proteolysis, corn, simulated, storage methods, moisture level

Cryptobia salmositica: Susceptibility of Infected Rainbow Trout, Salmo gairdneri, to Environmental Hypoxia

Using the sealed jar technique (also called residual oxygen bioassay), rainbow trout fry infected with Cryptobia salmositica were more susceptible than non-infected fish to environmental hypoxia. The Winkler technique (azide modification) was used to determine the residual dissolved oxygen in the water. Susceptibility of infected fish increased with 1) time after infection and was most evident in 3-7 wk infections, 2) the severity of anemia, and 3) increasing parasitemia. In prolonged infections, susceptibility was reduced when there were decreases in anemia and parasitemia; however, these infected fish were still more susceptible than non-infected fish. The increase in susceptibility of infected fish to hypoxia may be an important contributing factor to mortality of fish in hatcheries where there is inadequate water flow and overcrowding. The sealed jar technique is recommended in future studies on the pathogenesis of parasitic fish diseases, especially if the metabolic and/or respiratory systems are affected by the infection.

Volatile and water-soluble inhibitors of nitrogen mineralization and nitrification in a ponderosa pine ecosystem

Bioassay experiments were performed to test for inhibition of the processes of nitrogen mineralization and nitrification by organics in the forest floor of a ponderosa pine ecosystem. Water-extractable organics in the forest floor were tested by applying filtered extracts to the assay soil. The extract decreased nitrate production by 17.0% and decreased net mineralization by 4.1%. Inhibition by volatile organics was tested by placing vials containing forest floor or selected terpenoids of ponderosa pine in sealed jars containing the assay soil. Nitrate production was inhibited by 87.4% and 100%, and net nitrogen mineralization was inhibited by 73.3% and 67.7% in the jars with forest floor and terpenoids, respectively. Organics which are partially water-soluble and are volatile (such as terpenoids) would be very effective inhibitors of nitrogen cycling processes.

Influence of matric potentials on carpogenic germination of sclerotia ofSclerotinia sclerotiorum. II. A comparison of results obtained with different techniques

Four techniques to study the influence of soil matric potential on carpogenic germination of sclerotia of Sclerotinia sclerotiorum were compared. These were the inclined box, polyethylene glycol, sealed jars, and tension plates. The inclined box technique showed that at high matric potential (-0.1 to -0.4 bar) percent germination was higher on the soil surface than at 1 cm depth, but the opposite occurred at potentials of less than-1 bar. All techniques showed that at matric potentials close to 0 bar, germination would occur only if sclerotia were on the soil surface and adequate oxygen was available; buried sclerotia failed to germinate and many rotted. The lowest matric potentials that appeared to induce carpogenic germination using the inclined box, polyethylene glycol, and sealed jar techniques were -4, -7, and - 15 bars respectively, With the latter two techniques the matric potentials are probably understated; thus, although sclerotia can germinate in soil well below field capacity, the lower limit is probably that shown by the inclined box technique. This technique provides the closest approximation to field conditions.

Gill damage as a determinant of residual oxygen concentration in the sealed jar test.

fish to zinc and measur~ residual oxygen concentra­ tion after sealed jar test, secondly by putting healthy fish in sealed jars with known concentration of zinc and measuring residual oxygen concentration, and canparing both the above results with residual oxygen levels of healthy fish in clean water • .Additionally we have investigated the role of gill damage in deter­ mining the residual oxygen concentration by ligating gill arches, thus lllnit~ effective gill surface area, and carrying out sealed jar tests in clean water. In order to see if tissue oxygen consump­ tion may influence the residual oxygen concentration, the tests have been carried out at different tanperatures.

Effect of pH and the Role of N-Methylol Hydrolysis in Formaldehyde Release from Durable Press Fabric

A series of experiments are reported that demonstrate the effects of fabric pH on the release of formaldehyde from fabrics treated for durable press with formaldehyde- containing resins. Release, as measured by the AATCC sealed jar procedure, is a minimum in the neutral pH range; it increases as residual fabric acidity increases because of increased crosslink (C—O) hydrolysis, which produces N-methylol groups that hydrolyze in turn to form formaldehyde; release increases to even a greater extent as the fabric becomes increasingly alkaline because of the hydrolytic sensitivity of the C—N bond in pendant N-methylol groups at high pH. Similar pH effects are observed with methylated ("capped") resin. To determine the degree to which formaldehyde release results from N-methylol hydrolysis, a series of fabrics containing pendant N-methylol groups over a considerable range of concentrations were analyzed for N-methylol content before and after the AATCC measurement of formaldehyde release. In general, release is somewhat higher than expected from the decrease in N-methylol content. This suggests that other mechanisms, for example, release of free formaldehyde initially present in the fabric and hydrolysis of crosslinks to form additional pendant N-methylol, contribute to the formation and release of formaldehyde from these treated fabrics.

Formaldehyde release from a model N-methylol system

A model N-methylol reactant system based on pyrrolidone derivatives has been used to study the chemical factors that control formaldehyde release. Fabric samples of known composition were prepared from chemically pure reactants and formaldehyde release was determined by the AATCC Sealed Jar Test. This work provides support for prior suggestions and a more direct approach for understanding unexpected results from tests on post-and precure fabrics. In addition, new findings demonstrate that the N-methylol reactant, its byproducts, and pure zinc nitrate are capable of reducing the level of formaldehyde release.

Scavengers and pH Control in Aftertreatments for Reducing Formaldehyde Release from Durable Press Cottons1

Recent studies from this Center have demonstrated the influence of the pH of washing and of application of buffered solutions on the amount of formaldehyde released from finished fabrics in the standard AATCC sealed jar test. This work has been extended to include investigation of the effect of aftertreatments, and the in terrelated influence of pH, on formaldehyde release from durable press cottons. In cluded in the study were application of aftertreatments from solutions of salts, acids, and bases that produce various pH levels; formaldehyde scavenger agents; and scavenger agents in conjunction with pH control. Also, aftertreatments with ammonium hy droxide and ammonium salts were explored for condensing ammonia with free form aldehyde in the finish to give hexamethylenetetramine and thus reduce formaldehyde release. Fabrics were investigated that had been finished with dimethylol dihydroxyeth yleneurea, dimethylol ethyleneurea, and dimethylol isopropyl carbamate. Effectiveness of aftertreatments and scavenger applications for controlling formaldehyde release varied as a function of pH and the chemical nature of the finish. Depending on the particular finish, aftertreatments yielded formaldehyde release values ranging from considerably below that of the unwashed, finished fabric to several times that value.

Storage Stability of Vegetables Fermented with pH Control

ABSTRACTVegetables fermented by Lactobacillus plantarum with pH control were microbiologically stable during 12‐months' storage in hermetically sealed jars at ca. 24°C provided all fermentable sugars were removed during fermentation, and the products were stored at pH 3.8 or below. Fermented green beans, cucumbers, red and gieen bell peppers, and green tomatoes were thus rendered microbiologically stable. Fermented red beets and carrots, which contained residual sucrose, underwent secondary fermentation. Calculated carbon recoveries of the fermented vegetables ranged from 74–146%.