Cent Of Dry Weight Research Articles

Absolute Pollen Diagram from the British Late-Glacial

BLELHAM BOG, a National Nature Reserve 1.2 km west of Windermere, overlies two small infilled kettleholes in gravels of the latest major glaciation. In the western kettlehole the succession of late-glacial sediments includes two organic layers (carbon content approximately 20 per cent of dry weight) respectively 5 cm and 40 cm thick, separated by a silt of low organic content (carbon about 6 per cent). Two radiocarbon dates from the lower organic layer, 12,380 BC ± 230 and 12,330 BC ± 230 (Q 758), and descriptions of stratigraphy, pollen analysis, diatoms and Cladoceran remains in the late-glacial sediments have been published1–5.

The Influence of Some Nutritional and Management Factors Upon Certain Physical Attributes of Peach Quality1

Abstract The application of either N or Mg resulted in marked decreases in keeping quality, firmness, surface color, and to a lesser extent, specific gravity of peaches. The application of K was associated with increases in firmness, keeping quality and color, but a slight decrease in specific gravity of the fruit. The application of lime was not associated with changes in any quality factor determined. The application of P significantly increased firmness. Deviation from normal pruning practices resulted in increases in fruit firmness while irrigation decreased firmness. Treatments that lowered specific gravity usually lowered per cent dry weight. Evidence is presented which indicates that treatment influence upon fruit color was greatly increased in proportion to the number of years a treatment was applied.

Linear Erosional Furrows in Southampton Water

THE floor of the lower part of the estuary of Southampton Water (Fig. 1) has been examined with a Kelvin Hughes MS 43 transit sonar and an MS 36 echo sounder1. Upstream of Fawley the almost central deep channel is maintained by dredging to a least depth at low tide of about 11 m. On the western side the slope is a steady 1°–2°, but on the eastern side there is a wide shelf at about 2 m below port datum. To the seaward of Fawley there is a natural depth of 14 m below port datum. The sea bed consists of a soft mud made up of flocculated clay and fine silt particles. The flocculants have an equivalent mean grain size of about 5.5 Φ (22 µm). The mud is comparable with other marine muds having a moisture content of 120–220 per cent dry weight and a surface cohesion between 4–2 g cm−2. Occasional shell banks and gravel patches exist, especially near Calshot and on the eastern side.

Effects of Inoculation with Rhizobium and Arbuscular Mycorrhiza and Phosphorus on Growth, Yield and Nutrient Uptake by Pea Grown in Soil

The experiment was conducted in pot at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh to study the response of pea (Pisum sativum) cv. IPSA Motorshuti-3 to dual inoculation with Rhizobium (R) and Arbuscular Mycorrhiza (AM) in presence and absence of phosphorus (P) on root colonization, spore population, nodulation, nitrogenase activity, growth, yield, and nutrient uptake by shoot. The performance of Rhizobium inoculant alone was superior to control in all the parameters of the crop studied. Among the treatments dual inoculation with Rhizobium and Arbuscular Mycorrhiza in combination with 25 kg P ha-1 performed best in recording per cent root colonization, number and dry weight of nodules, dry weight of shoots, nitrogenase activity, number of pods/plant, number of seeds/pod, pod and seed yields, and nutrient uptake by pea. This treatment combination recorded green pod yield of 12.0 g/plant (140 % increase over control) and mature pod yield of 7.0 g/plant (146% increase over control). The effect of this treatment was however similar to the effect of dual inoculation with R and AM in combination with 12.5 kg P ha-1 in most of the parameters. From the view point of nodulation, nitrogenase activity, growth, and yield of pea, dual inoculation with Rhizobium inoculant and arbuscular mycorrhiza in combination with 25 kg P ha-1 was considered to be the best for the supply of balanced combination of nutrients for achieving the maximum output through cultivation of pea in Shallow Red Brown Terrace soil of Bangladesh. Keywords: Pea; Rhizobium; Arbuscular mycorrhiza; Phosphorus DOI: http://dx.doi.org/10.3329/bjm.v27i1.9164 BJM 2010; 27(1): 22-27

Composition of the gut contents of third-instar tsetse larvae ( Glossina morsitans westwood)

1. 1. The tsetse fly nourishes its young, intra utero. 2. 2. The “milk” contains 48 per cent of dry weight as lipid. 3. 3. The free lipids contained are phospholipids, cholesterol, triglycerides and a number of unidentified lipids. 4. 4. The “milk” also contains 1·4 g/100 ml of tyrosine.

On the content of myoglobin in human muscles.

Abstract A quantitative method of determining the content of myoglobin and hemoglobin in human muscle is described.A piece of muscle, 1–4 g, is ground with dry ice, homogenized and extracted with 0.02 M phosphate buffer, pH 7.4. After being centrifuged at 15,000 × g, the solution is concentrated by dialysis against 25% polyethylene glycol solution. The hemoproteins are separated by gel filtration on Sephadex G 75, identified by the absorption spectra of their carbon monoxide compounds and quantitatively determined by the pyridine hemochrome method.The content of hemoprotein is calculated as per cent of dry weight, the latter being determined on the original homogenate.In an autopsy material, mainly consisting of patients in upper age‐groups with chronic disease and modest physical activity, average values of 0.9 g myoglobin per 100 g dry muscle were found in hearts (left ventricle), whereas corresponding values for diaphragm, abdominal muscle and muscles of the thigh were 1.1, 1.6 and 2.2 g per 100 g dry muscle. It is assumed that values in healthy adults may well be somewhat higher. From these values it is calculated that the total amount of myoglobin in an adult male is in the range of 120–150 g, corresponding to an iron pool of 0.37‐0.47 g or approximately 7/5 of the amount of hemoglobin iron.Comparisons with determinations arrived at by other methods are made, and some aspects of the physiology of myoglobin and other hematin compounds are discussed.The insoluble or “residual” hematin has been determined. It could be shown that the major part of this hematin can be accounted for by the mitochondrial hemoproteins, the remaining part in all probability deriving from hemoglobin.

Ion transport and phosphorylation in dried and rehydrated yeast cells.

BAKER'S yeast, consisting of almost 70 per cent water, can be dried to a moisture content of 7–8 per cent of dry weight without serious impairment of viability or fermenting capacity1,2. The cell membrane in such cells seems to be altered in such a way that considerable leakage of cytoplasmic material occurs when the cells are suspended in water at or below room temperature. Suspension of the cells in water at 35°–45° C prevents excessive loss of cytoplasmic constituents3. The “active dry yeast” to be considered here is dried yeast rehydrated at 35° C in which the cellular permeability barrier has been restored. The lipid composition of yeast cells can be altered by this process4. I have investigated the question of whether such cells are still capable of active ion transport, which is one of the normal membrane functions5–7.

The amount, distribution and metabolism of soluble polysaccharides in human dental plaque

Twenty-four-hr accumulations of human dental plaque were extracted with distilled water and cold 0.5M sodium hydroxide for soluble hexose components. Seventy-six plaques had a mean soluble polysaccharide content of 9.0 (S.D. 3.52) per cent dry weight of plaque. The major component sugars of this material were glucose and fructose, and only small amounts of typical bacterial cell wall sugars were present. Plaque which was dried and stored before extraction gave higher values for soluble polysaccharide 10.7 (S.D. 2.46) per cent dry weight of plaque than fresh plaque collected into water 7.3 (S.D. 3.95). When plaque was incubated at 37 °C for 2 hr the water-soluble polysaccharide generally decreased indicating that it was metabolised. The sodium hydroxide soluble polysaccharide often increased. It is concluded that this polysaccharide is a major part of the plaque matrix, that it is present as the extracellular polysaccharides dextran and levan, and that some part of the water-soluble fraction of this material can be metabolised by the plaque.

Thiobarbiturate-reacting materials in microorganisms.

The amount of thiobarbiturate-reacting material in 51 strains of bacteria and three yeasts was determined. Reactive material was found to be present in all of the gram-negative bacteria examined. It was assumed that the reactive material in this case was primarily 2-keto-3-deoxyoctonate (KDO), an eight-carbon sugar acid which is usually associated with the cell wall lipolysaccharide of members of the Salmonella-Escherichia group. Very little reactive material could be detected in the gram-positive species and yeasts that were examined. When expressed as per cent dry weight, the gram-negative bacteria exhibited about eight times more reactive material than the gram-positive species. It is suggested that the small amount of reactive material detected in gram-positive cells and yeasts is due to compounds other than KDO.

Relative Turgidity Determinations for Native and Plantation Shortleaf Pine in Southern Illinois

Only small variations in relative turgidity were found for native, disjunct shortleaf pine (Pinus echinata) before and at the end of a record 48-day drought. Remnant 25-year-old plantation shortleaf pine underplanted with hardwoods had relative turgidity values equivalent to those not underplanted which maintained a full canopy. Year-old needles had equivalent relative turgidity values, higher per cent dry weight, and lower leaf moisture content than current-season needles in August.

Cold-hardiness in the forest tent caterpillar, Malacosoma disstria Hübner (Lasiocampidae, Lepidoptera)

The seasonal variations in glycerol content and supercooling temperatures in the eggs of the forest tent caterpillar, Malacosoma disstria Hübn., were investigated. Glycerol accumulated in the autumn and early winter and reached a peak in January when 35·2 per cent (dry weight basis) was recovered from eggs and decreased to <1·0 per cent during the post-diapause stage in spring just before hatching. Temperatures between 10 and 32·2°C caused a rapid decrease in glycerol during post-diapause. At 5°C the glycerol concentration decreased more slowly and the eggs did not hatch. Supercooling temperatures of −29·5°C were recorded for summer eggs, the lowest supercooling temperatures occurred from November to April, when they ranged from −32·6 to −40·8°C, and did not increase until a few days before hatching after exposure to warm spring temperatures. The concentration of glycerol is not completely correlated with cold-hardiness; accordingly other factors additional to glycerol are presumably involved. Approximately 80 per cent of newly hatched unfed larvae survived for 10 days at −1·0 to 15°C, but below and above this range survival was low.

Chemical Changes inLolium temulentumL. after Treatment with (2-Chloroethyl) Trimethylammonium Chloride (CCC)

Two experiments with an inbred line of the summer annual Lolium temulentum L. are described. The plants were grown under 18-hour days in 8.5 cm pots containing pure vermiculite. The first experiment was concerned with the effect of (z-chloroethyl) trimethylammonium chloride (CCC) upon soluble carbohydrate content, and the second with the combined effects of CCC and nitrogen upon soluble carbohydrate, free α amino-N, and chlorophyll content. Concentrations of CCC from 0.01–0.5 M inhibited growth and induced large increases in the free sugar content of the plant. With 0.05 M CCC and above, large amounts of fructosan were formed. Adequate nitrogen supply lowered the free sugar level and large amounts of free α amino-N appeared. Crude protein content (per cent dry weight) was increased by CCC at low nitrogen levels but was less affected when N was adequate. Chlorophyll production was stimulated in the presence of CCC. The metabolic implications of the CCC-induced chemical changes are discussed and a possible scheme for CCC action is suggested.

CHEMICAL AND ULTRASTRUCTURAL COMPARISON OF SYNTHETIC AND PATHOLOGIC MEMBRANE SYSTEM.

Characteristic membranous bodies have been previously reported in the cytoplasm of the cerebral neurons in Tay-Sachs disease (1) (Fig. 1). Subsequently (2) these lamellated particles were isolated from homogenized autopsy tissue by differential and density gradient centrifugation and subjected to extensive chemical analysis. The membranous cytoplasmic bodies (MCB) were found to consist of about 50 per cent (dry weight) gangliosides and could account for the accumulation of this complex sphingolipid which characterizes this lipid-storage disease. The appearance and composition of the MCB suggested: (1) that they might arise from an alteration of cytoplasmic organelles, or (2) that they were formed spontaneously by interaction of the component lipids in a fashion analogous to myelin figure formation (3). Chemicals approximating the known composition of the MCB were combined in proper proportion in vitro as a test of this latter hypothesis. The resultant aggregates were examined with light and electron microscopy.

Ergot-type alkaloids in vegetative tissue of Rivea corymbosa (L.) Hall. f.

The ergot alkaloids, ergine and isoergine, were found in the leaf and stem but not in the root of Rivea corymbosa, which had been grown in a greenhouse. The amount per plant increased with time reaching a maxima of 0.027 and 0.012 per cent dry weight in the leaf and stem, respectively, after approximately 9 months' growth.

Relationship Between High Overburden Pressures and Moisture Content of Halloysite and Dickite Clays

High-pressure compaction studies (up to 386,000 psi) were conducted on halloysite and dickite clays. The remaining moisture content in per cent (dry weight) was plotted versus the logarithm of pressure in psi. For halloysite clay there is a straight-line relationship between 1000 and 260,000 psi ( M = 40.1 − 6.66.1og P ), and for dickite clay the relationship between the pressure (psi) and the moisture content (per cent) can be expressed by the formula M = 26.7 − 5.04.1og P between 200 and 120,000 psi. X-ray analyses were made on compacted samples in order to determine any possible mineralogic changes with increasing overburden pressure. In addition, the permeability of dickite clay at an overburden pressure of 15,000 psi was calculated.

The disintegration of yeast with dry ice and some properties of the extract

AbstractA simple procedure for the disintegration of yeast cells, by which litre quantities of cell extract (approximately 11 per cent dry weight) may be obtained, is described. The fresh yeast cake is treated with dry ice in a high speed electric homogenizer after which it is left to thaw out at 0°. No addition of buffer has to be made, and the cell juice obtained after centrifugation of the resulting slurry appears to contain different subcellular particles and various enzymes in a relatively native state.When the extract is incubated at higher temperatures, proteolysis will rapidly change the electrophoretic and enzymatic properties, which indicates that procedures involving autolysis may be dangerous when information about the chemical composition of the native enzymes is desired.

Biosynthesis of Damascenine in Nigella damascena L.

DAMASCENINE is present in the seeds of Nigella damascena L. to the extent of about 0.1–0.3 per cent (dry weight). The majority of the alkaloid is present in the testas. The seeds of other Nigella species hitherto investigated possess only traces of the base.

Premigratory Hyperphagia in Birds

The unusual lipid metabolism of migratory birds is of interest in connection with human problems of obesity for two reasons : (1) lipogenesis and lipolysis are extremely rapid in some species and (2) temporary obesity can be readily induced experimentally by photoperiod manipulation. Wild birds appear to exhibit three patterns of migratory obesity: (1) short range migrants which attain moderate obesity but begin migration before peak deposition; (2) short range migrants which begin migration after peak deposition; (3) and long range migrants which become extremely obese (50 per cent of wet weight, 75 per cent or total dry weight or 300 per cent of non-fat dry weight of body composed of fats) just prior to long flights (such as over the Gulf of Mexico). Energy for the long flights is derived entirely from lipids. Experimental work so far has largely concerned short range migrants in which moderate hyperphagia and lipid deposition can be induced by direct stimulation of long photoperiods. New data obtained from birds killed during migration at television towers indicate that experimental work with long range species will prove instructive. A working but unproved hypothesis is that migratory obesity involves a temporary simultaneous alteration of both nervous pathways (i.e., hyperphagic-hypothalamic obesity) and metabolic pathways (i.e., metabolic type of obesity).

Effects of Soil Insecticides and Absorbents on Plant Sugars and Resulting Effect on Mite Nutrition1

The effects of DDT and various absorbent materials as soil additives on the composition of Black Valentine beans and Clark soybeans and on the Tetranychus telarius (L.) populations developing thereon were investigated in the greenhouse. Treatments included DDT only at 800 or 1,600 pounds per acre and DDT at both levels in combination with six levels of the absorbent material as well as an untreated check. Mite development was measured by counting the progeny developing over a period of 8 days from five young adult female mites introduced to a detached leaf disk, each disk being one of four replicates. Dry weight of foliage was calculated and foliage was analyzed for total and reducing sugar, total nitrogen, phosphorus, and potassium. Analyses for correlation coefficient (r) were made on populations with the results of the foliage analyses. In Black Valentine beans DDT added to the soil at both 800 and 1,600 pounds per acre increased total and reducing sugars, nitrogen and T. telarius populations over the untreated check, while decreasing phosphorus, potassium, and dry weight of foliage. Addition of Hydrodarco B, Aqua Nuchar A, and Nuchar C-115-A generally restored the chemical components of the beans and also the mite populations to the levels of the untreated check. Mite populations were thus correlated positively with reducing sugar and nitrogen, in some cases total sugar, and negatively with per cent phosphorus, potassium, and dry weight of foliage. Peat moss, calcium hydroxide, and Fisher activated charcoal pellets did not function effectively as absorbents; Norit-A and Mallinckrodt activated charcoal alleviated the phytotoxic effects of DDT but did not influence mite populations consistently. Clark soybeans were not as sensitive to DDT as Black Valentine beans. The percentages of reducing and total sugar were elevated much less and lower concentrations of absorbent were required to reduce these values to the original levels. Hydrodarco B was the only absorbent to affect the chemical composition and mite populations as consistently as in Black Valentine beans although similar trends were noted with Aqua Nuchar A and Nuchar C-115-A. These studies demonstrated that at least one organic constituent of the plant, reducing sugar, has been markedly influenced in the plant by the addition of high levels of DDT to the soil. Also it has been shown that these plant sugars can be related to the development of a plant feeding mite such as T. telarius.

The separation and some chemical, physical and biological properties of a nucleoprotein from Streptococcus pyogenes

A nucleoprotein, called component 4, has been isolated by chemical fractionation procedures from extracts of Streptococcus pyogenes. The S. pyogenes extracts were prepared by sonic radiation of washed whole cells. The final product amounted to 4% of the cell on a dry weight basis. The purified product contained on per cent dry weight basis, 14.2, N 2; 4.9, RNA; 7.2, lipid; 2.3, hexose; 0.56, P; 1.0, rhamnose, and 0.1, hexosamine. Physical characterization data reported were electrophoretic mobility ( u) −5.1 × 10 −5 sq. cm./v./ sec. at pH 8.6 in 0.10 μ barbital buffer; M w ~ 3 × 10 6; M n ~ 1.7 × 10 6; E 280 1% = 14.9; E 260 1% = 19.4; V ̄ = 0.78; Δn C = 0.00171; D 20 w = 2.1 × 10 −7 sq. cm./sec . Component 4 isolated from four different strains of S. pyogenes, N19 and B19 (type 19), S43 (type 6), and 12RN (type 12) was serologically indistinguishable. Rabbit antisera to component 4 did not protect mice against intraperitoneal infection with virulent streptococci.