Decline In Protein Content Research Articles

Enzyme transmission during crossflow filtration of yeast suspensions using gas/liquid two-phase flows.

The optimal conditions for recovery of an enzyme were determined using gas/liquid two-phase flows. When filtering the enzyme-only solution under single-phase flow conditions, severe fouling occurred. This fouling was manifest as a decline in flux to less than 2% of the initial water flux and a decline in protein concentration in the permeate to 30% of its initial value, during a five-hour filtration period. When yeast cells were added under the same experimental conditions, enzyme transmission was maintained at 100% for the five-hour period and the enzyme mass flux was twofold higher. During gas-sparged microfiltration of the enzyme/yeast mixture in a permeate-recycling mode at the same liquid flow rate, gas/liquid slug flow strongly decreased the transmission of the enzyme (70% decrease), even though the permeate flux was improved (140% improvement). As a result, the mass flux of the enzyme was significantly reduced. However, with a bubble flow pattern, the permeate flux was 1.5 times higher and the transmission was maintained at a high level. The enzyme mass flux was then 25% higher when compared to single-phase flow filtration conditions. During diafiltration experiments with a bubble flow pattern, a 13% higher enzyme recovery was achieved.

Lysosomal proteolysis in distally or proximally denervated rat soleus muscle.

We examined the mechanism of accelerated proteolysis in denervated rat soleus muscles. The soleus was denervated by severing either the tibial nerve (proximal, short stump) or sciatic nerve (distal, long stump) at 24, 48, 72, or 96 h before excision. Twenty-four hours after denervation, the extent of atrophy was similar for proximal and distal denervation, although lysosomal latency declined in both groups. After 48 and 72 h, denervation resulted in a decline in protein content, an increase in in vitro protein degradation, and a decline in lysosomal latency, all of which were greater in proximally denervated than in contralateral distally denervated muscles. These differences between acute responses of proximally and distally denervated muscles suggest the retention of some factor in the longer nerve stump that attenuates atrophy. After 96 h, total protein loss, protein degradation, and lysosomal latency were similar for proximal and distal denervation, suggesting the loss of axoplasmic flow from the long nerve stump.

Biochemical composition of Aurelia aurita in relation to age and sexual maturity

Dry weight (DW), ash free dry weight (AFDW), and proximate biochemical composition were examined for a full range of sizes of whole medusae of the scyphomedusa Aurelia aurita. Dry weight ranged from 3.07 to 3.91% of wet weight (WW), and was fairly uniform throughout the size groups. Ash free dry weight ranged from 25.6 to 46.0% of DW, with values significantly greater in ephyrae and medusae < 20 mm. The sum of carbohydrate, protein and lipid fractions, termed “total organics”, is often taken to be synonymous with AFDW, but values were consistently lower than AFDW, ranging from 5.56 to 22.76% of DW. Even after AFDW had also been calculated assuming water of hydration to be 11.7%, there were still differences between the two values. Whole Aurelia aurita medusae displayed the typical characteristics of gelatinous predators, with low carbohydrate (0.10–1.12% of DW), intermediate lipid (3.50–11.50% of DW), and high protein (2.07–28.56% of DW) content. The biochemical composition of isolated umbrellar and gonadal tissues of medusae > 50 mm were examined, and in every size group, “total organics” were greater in gonadal than umbrellar tissue. The greater organic content of gonadal tissue was the result of an increase in all three biochemical fractions, with carbohydrates and proteins displaying the greatest differences. Mean values ranged from 0.33 to 0.85% carbohydrate, 2.34–8.31% protein, and 0.87–2.91% lipid in umbrellar tissue, compared with 1.08–2.10%, 4.38–22.98%, and 2.59–6.08%, respectively, in gonadal tissue. The biochemical content of ripe oral arms, i.e. those containing dividing eggs and planula larvae, was similar to that of the maturing gonads. Protein content was greatest in gonads of medusae 60–110 mm, before decreasing significantly with increasing bell diameter. Rapid growth and maturation in the 60–110 mm size group was coincident with the spring peak of mesozooplankton abundance in Southampton Water, while the decline in protein content may be explained by loss in condition of “spent” medusae.

Effects of growth hormone and an antiserum to rat growth hormone on serum IGF-I and muscle protein synthesis and accretion in the rat.

Rats were injected twice daily for up to 10 days with GH or with a polyclonal antiserum to rat GH, commencing at 21-22 days of age. Administration of bovine or human GH (1mg/day) improved whole body growth rates by 22% and 29% respectively. Plantaris muscle mass was also increased, by 7 and 14% respectively. Anti-GH injected twice daily resulted in a 7% decrease in body weight at 4 days and a 10% reduction by 10 days. Similar decreases were observed in the total protein content of plantaris and soleus muscles. The decrease in the fractional rate of protein synthesis was proportionately greater than the decline in protein content in plantaris muscle whereas in the soleus no change in the rate of protein synthesis was observed, suggesting that the effect on this muscle was due to an increase in the rate of protein degradation. Serum total IGF-I was unchanged by treatment with either GH or anti-GH while the amount of hepatic IGF-I mRNA was also unaffected by anti-GH injection. These data are consistent with a direct effect of GH or an effect mediated by an autocrine/paracrine mechanism of action on muscle but do not support a role for serum total IGF-I as an endocrine mediator of GH action.

Flower senescence in daylily (Hemerocallis)

Daylily (Hemerocallis hybrid cv. Cradle Song) flower development and senescence was categorised into seven stages, each separated by one day. As the bud developed (Stages I to III) its fresh and dry weight increased, but during flower opening (Stages III to IV) only the fresh weight increased, reaching a maximum when the flower was fully open (Stage IV). Fresh and dry weight declined as the flower senesced (Stages V to VII), and the petal tissue became water‐soaked. Flower respiration was relatively constant through Stages I to III, but during opening the CO2 production increased, then declined as the flowers senesced. Ethylene production was low throughout flower development, and there was a transient increase, up to 2.5 nl flower−1 h−1, as flowers senesced. Petal protein content per gram fresh weight decreased throughout flower development and senescence either on or off the plant. One‐dimensional SDS‐PAGE revealed a general gradual loss of protein bands during flower senescence and loss of some specific bands (e.g. at M, 30 000 and 40 000). Flowers, detached from the plant at Stage III, placed in deionised (DI) water for 7 h and then transferred to fresh DI water or actinomycin D (25 mg l−1), showed an increase in fresh weight up to a maximum at about 12 h after transfer, followed by a rapid decline. By 48 h the flowers had completely senesced, the tissue becoming watersoaked and free moisture appearing on the tips of collapsed petals. In contrast, senescence of flowers treated during opening with cycloheximide (1 mM) was greatly delayed, with little loss of fresh weight or reduction in flower diameter, even up to 181 h after transfer. When such flowers did finally senesce, they did not show the same pattern of senescence as seen with those in water or actinomycin D. Cycloheximide‐treated flowers wilted gradually and showed no water‐soaking and no free moisture at the petal tips. Cycloheximide treatment retarded the decline in protein content of the petals; and the protein population, as visualised by SDS‐PAGE, was maintained for up to 204 h after transfer to cycloheximide.

Changes in amino acids and protein metabolism in Egyptian cobra ( Naja haje) during hibernation

1. 1.Total protein, GOT, GPT, alkaline phosphatase and total free amino acid content in the brain, liver and kidney were studied in the hibernating, arousing and normothermic cobra ( Naja haje). 2. 2.Tissues showed a decline in protein content which started in the prehibernating animals. At the low body temperatures in hibernation both synthesis and degradation would be reduced. The fall in protein content suggests synthesis is reduced more steeply than is degradation. Recovery of protein biosynthesis was demonstrated during arousal. 3. 3.In aroused animals, the levels of free amino acids in the tissues examined were higher than in hibernating ones or in normothermic controls studied in summer. 4. 4.A decline in GOT activity was recorded in the hibernating animals. The enzyme activity showed recovery on arousal. A similar trend was observed for the GPT activity in brain and kidney. 5. 5.The activity of alkaline phosphatase was also examined in the different tissues. The correlation of these changes to the different phases of hibernating cycle is discussed.

Zur chemischen Zusammensetzung der CtenophorePleurobrachia pileus in der Kieler Bucht

The chemical composition of the ctenophorePleurobrachia pileus was investigated in March, May and July 1981 in Kiel Bight, western Baltic. The results of all determinations yielded low values compared with other zooplankton groups. Dry weight made up 1.95 to 2.28% wet weight with a minimum occurring in may. Ash-free dry weight amounted to 28–37% of the dry weight but exhibited a maximum in May. Carbon and nitrogen analyses yielded amounts of between 2.6–4.7% of the dry weight and 0.5–1.0% of the dry weight, respectively. Both elements reached lowest levels in May. Proteins reached a minimum in May, too, and values ranged between 2.5 and 5.1% of the dry weight. However, lipids as well as carbohydrates exhibited highest values in May and ranged from 0.8 to 1.6% and 0.8–1.1% of the dry weight, respectively. The C∶N values increased between March and July from 3.7∶1 to 6.7∶1, indicating a decline in protein content. To relate the biochemical compounds to organic matter I used three different approaches: (1) On the basis of ashfree dry weight, carbohydrates remained constant whereas lipids increased from March to July. A minimum of proteins occurred in May. The three compounds made up only 14–22% of ash-free dry weight. (2) Organic matter approximately equals organic carbon content multiplied by 2. Proteins, lipids and carbohydrates summed up reached 61–100% of this reference value and the seasonal course of these compounds changed in a drastic way: proteins decreased, whereas lipids as well as carbohydrates showed a relative maximum in May. (3) Finally, the carbon content of each biochemical compound was calculated in relation to total carbon content measured via C/N analysis. On this basis, 63–105% of total carbon were recovered, and the course of seasonal changes agreed with that of the second approach. A comparison of these three approaches suggests that comparative calculations based on carbon measurements are more valid than those based on ash-free dry weight. The results show that seasonal changes in the amount of organic matter and the biochemical composition occurred. Dry weight was lowest in May, which could be due to the low salinity environment recorded at that time and the corresponding low salt content of the tissue. The observed relative maxima of lipids and carbohydrates in May may be explained by good food conditions since high zooplankton densities are characteristic for this month in Kiel Bight.

Freezing injury in spinach leaf tissue: Effects on water‐soluble proteins, protein‐sulfhydryl and water‐soluble non‐protein‐sulfhydryl groups

Freezing of spinach leaf discs (Spinacia aleracea L. cv. Estivato) resulted in an irreversible and parallel loss of protein‐sulfhydryl (SH) and water‐soluble protein. This decrease was inversely related to the increase in freezing injury as determined by the loss of electrolytes from the tissue after thawing. Loss of proteins and protein‐SH occurred during freezing of the tissue and was not enhanced by thawing. The parallel decreases in content of soluble proteins and SH groups make it impossible to determine whether oxidation of protein‐SH groups is the primary step in decline of protein content. During freezing the content of non‐protein‐SH compounds, mainly glutathione (GSH), was decreased to a lesser extent than that of protein‐SH. Contrary to protein‐SH, the levels of non‐protein‐SH declined substantially after thawing. The data indicate that GSH is not directly involved in protection of soluble proteins against freezing‐induced denaturation.

Physiological Control of Arginine Decarboxylase Activity in K-Deficient Oat Shoots

The effect of K-deficiency on the putrescine biosynthetic enzyme, arginine decarboxylase (ADC), was investigated by growing oat (Avena sativa L. var Victory) plants on a low-K, but otherwise complete nutrient medium in washed quartz sand for up to 18 days. Enzyme activity rose as the concentration of KCl was dropped to 0.6 millimolar or below. However, growth was not inhibited significantly at 0.6 millimolar KCl. ADC activity increased in the whole shoot of K-deficient oats throughout the period of 6 to 18 days, but remained constant in normal plants. At 18 days, ADC activity in entire K-deficient shoots was 6 times greater than in normal shoots, while in the first (oldest) leaf, ADC specific activity increased to more than 30 times the specific activity in the first leaf of normal plants. This effect was due to a moderate rise in total ADC activity in the first leaf between 6 and 18 days, accompanied by a significant decline in protein content. Replacing K(+) with Na(+) or Li(+) significantly inhibited the increase in ADC activity in K-deficient oats, while Rb(+) depressed the specific activity to a level below that in normal plants. An alternative putrescine biosynthetic enzyme, ornithine decarboxylase, was also examined. The specific activity of a pelletable form of the enzyme was increased 2-fold in the shoots of K-deficient oats.

Variations in Protein Content Due to Proteolytic Enzyme Activities and Their Influence on Susceptor Resistant Response in Maize — Erwinia carotovora var. chrysanthemi Host-Pathogen System

Summary The susceptibility of maize varieties ‘Vijay’, ‘Popcorn’, and ‘Swan’ towards the three isolates ‘Columbia’, ‘Hawaii’, and ‘Wisconsin’ of Erwinia carotovora var. chrysanthemi was due to increase or decline of protein content, enhanced proteolytic enzyme activities, and increase or diminution of total amino acid output in stalk- and leaf-tissues of middle- and old-age-group of plants. The interaction of the three activities was at the summit 16 d after infection in all the three age groups of plants. The heightened proteolytic enzyme activity with concurrent release of amino components as nutrients sustained susceptibility. In younger tissues of these cultivars such a response was maintained through restricted release of amino acids, specially those which were inhibitory to the 3 isolates of the pathogen. This was apparent especially in variety ‘G.S.2’, where protein accumulated in infected tissues with simulate lessening of excreted amino compounds. Here the protein incorporated in itself all such free amino acids which acted as inhibitors. The resistance in young stalk- and leaf-tissues of ‘Pant-7421’ variety and young and mature tissues of ‘Pool’ variety was engineered through decline in the total content of nutritionally utilizable free amino acids. The resistant response of middle- and old-age-group of tissues of variety ‘Pant’ and the middle aged tissue of variety ‘Pool’ was conducted through diminution of protein, accompanied with vigorous proteolytic enzyme activity and high level of total amino acid output, which acted as repressor to the bacterium during host-pathogen interplay.

Physiological Effects of Colchicine on Growth and Metabolism of Mungbean (Phaseolus aureus L.) Seedlings and α-Amylase Production in Rice (Oryza sativa L.) Endosperm

Summary The effects of various concentrations of colchicine on mungbean ( Phaseolus aureus L.) seedling growth were studied. Growth inhibition began at 0.25 mM concentration, the hypocotyls became swollen and roots blunt by colchicine treatment. Gibberellic acid (GA 3 ) was capable of preventing the inhibition of hypocotyl elongation, whereas kinetin could relieve the inhibition of both hypocotyl and root. IAA reversal was of the same order as with simple water. There was accumulation of nucleic acids and decline in protein content in colchicine-treated seedlings resulting in increased RNA/protein and DNA/protein ratios. Colchicine could not induce α-amylase production in rice ( Oryza sativa L.) endosperm halves to a significant level, but could prevent partially GA 3 -induced α-amylase production in this system. Coincident with α-amylase production in rice endosperm, there was an increase in protein content, whereas nucleic acids changed little in this system.

Summer Feeding Ecology of Lesser Snow Geese

Changes in the characteristics of the available vegetation at the mouth of the McConnell River, N.W.T. (60050'N, 94025'W), during the arctic summer were measured in 1971 and 1973. The concurrent variations in the feeding behavior of adult lesser snow geese (Chen caerulescens) were measured in 1973. Standing crop of vegetation in both grazed and ungrazed sites reached a maximum in the first week of August. The crude protein content of ungrazed vegetation showed a maximum value in late July, with a rapid decline in August. Grazed vegetation showed a similar rise, but with little decline in protein content in August. Snow geese and their goslings had access to a food supply increasing both in quantity and quality during the critical post-incubatory period. In this period adult female geese spent 17 hours per day feeding, probably as much time as was physically possible. Other parameters of feeding behavior varied predictably with the changes in vegetation characteristics. J. WILDL. MANAGE. 41(1):48-55 Members of the Hudson Bay population of lesser snow geese breed in colonies on coastal, tundra marshes (Cooch 1961). Throughout the summer, breeding adults feed almost exclusively on the green shoots of Gramineae, Cyperaceae, and Juncaceae. Arctic grasslands traditionally have been considered to have a low annual primary productivity and a low vegetational nitrogen content (Russell 1940, Wilson 1954, Bliss 1971). Paired adults arrive on the breeding grounds in late May or early June. Winter snow rarely melts by this time. Nesting starts as soon as suitable sites are available. There is little feeding by nesting adults during incubation, and females may lose more than 30 percent of their body weight during this period-including a large proportion of their breast muscle (Ankney 1974:102-107). This protein drain is exacerbated further by a major molt that occurs within 3 weeks of the end of incubation. Breeding geese must recover their lost body weight, replace their flight feathers, and prepare for southward migration in a twomonth period. They must do this while feeding on what is considered to be a nutrient-poor food supply. Compared to most grazing vertebrates, geese have a simple alimentary tract. Vegetation passes through the gut in 2 to 4 hours (Marriott and Forbes 1970, Ziswiler and Farner 1972:397), and large plant fragments are visible in the faeces. This rapid passage of food leaves little opportunity for any digestive process more complex than the simple absorption of cell solutes. Mattocks (1971) found no evidence of cellulose digestion in the digestive caecae of Anser

Effect of Site and Fertilization on Protein Content of Native Grasses

Highlight: Protein content of selected native range grass and sedge species was followed during the course of the growing season over a y the magnitude of increase, however, varied greatly between sites and species. Decline in protein content is progressive in all species with the advance in maturity regardless of fertilizer treatment level or site. However, the rate of protein loss is accelerated with fertilization and becomes more rapid with a decline in summer moisture. Cool-season species show a more rapid protein loss than was observed from warm-season Bouteloua gracilis. The length of the grazing period when forage values remain near the minimum protein requirement is appreciably extended on some sites with certain species, especially Bouteloua gracilis. Proper range management must take into consideration the potential of each major range site and the inherent species capabilities to produce and maintain a high level of protein for an extended period of grazing.

Age changes in nucleic acids, protein, free amino acids and water content of the skin in the male garden lizard in natural surroundings.

Some of the biochemical components of the skin of the garden lizard, &lt;i&gt;Calotes versicolor&lt;/i&gt;, have been analyzed in relation to age. The DNA content was found to decrease sharply during the rapid growth phase and again between the fully matured and older group. The RNA content reached its peak at the fully matured stage, followed by a decline. The RNA/DNA and RNA/protein ratio showed the same trend. A sharp decline in protein content was recorded during the rapid growth phase. Protein content, expressed on the basis of DNA, showed the same trend. An increase in protein content was found between the sexually matured stage and the older group. The free amino acid level did not show significant age-related change. During the period between the rapid growth phase and sexual maturity the water content of the skin showed a significant increase and remained almost constant thereafter.

Effect of Kinetin on Ribosomes of Excised Barley Leaves

AbstractThe changes in the amount and the composition of ribosomes in excised barley leaves floated on water or on 10 mg/l kinetin solution in the dark were examined.The rapid loss of polyribosomes and ribosomes in leaves floated on water was greatly retarded by kinetin. The ribosomes‐polyribosomes which originally contained 49 per cent protein showed substantial decline in protein content in leaves floated on water but only slight decline in leaves floated on kinetin solution. It is suggested that kinetin by stimulating RNA synthesis and by suppressing the activities of rihonuclease and peplidase may preserve the ribosomes in excised leaves.