Low protein

About: Low protein is a research topic. Over the lifetime, 8139 publications have been published within this topic receiving 213225 citations.

Fragment screening by surface plasmon resonance.

Abstract: Fragment-based drug discovery is a validated approach for the discovery of drug candidates. However, the weak affinity of fragment compounds requires highly sensitive biophysical techniques, such as nuclear magnetic resonance (NMR) or X-ray crystallography, to identify hits. Thus the advantages of screening small fragment libraries are partly offset by the high cost of biophysical analyses. Here we present a method for biosensor-based fragment screening using surface plasmon resonance (SPR). In order to reduce the false positive detection rate we present a novel method of data analysis that incorporates multiple referencing with ligand efficiency. By implementing all necessary steps for assay design, data analysis and interpretation, SPR-based fragment screening has potential to eliminate all nonspecific (false positive) binders. Therefore, given the advantages of low protein consumption, rapid assay development and kinetic and thermodynamic validation of hits, SPR can be considered as a primary screening technology for fragment-based drug discovery.

Direct sampling and in situ observation of a persistent copepod aggregation in the mesopelagic zone of the Santa Barbara Basin

Abstract: Observations from a one-person submersible (“Wasp”) in fall, 1982, revealed a persistent aggregation of non-migrating, Stage V copepodites of Calanus pacificus californicus Brodsky in a band 20±3 m thick at a depth of 450 m, about 100 m above the bottom of the Santa Barbara Basin, California. Copepod abundances, calculated from nearest-neighbor distances measured directly from the submersible, yielded maximum densities of 26×106 copepodites m-3. Quiescent behavior, low laminarinase activity, low protein content, high lipid content and evidence of low excretion rate all suggest that these copepodites were in a state of diapause. Diapausing C. pacificus californicus at other locations along the eastern Pacific coast were also captured in discrete depth plankton tows. Both the submersible observations and the net collections suggest that the dense aggregation of diapausing copepods we observed in the Santa Barbara Basin was a phenomenon associated with seasonal upwelling cycles, and that such aggregations occur during non-upwelling periods when food is scarce in surface waters. Numerous predators, especially the deep sea smelt Leuroglossus stilbius, were observed feeding upon the aggregated copepods; thus, in contrast to the conventional picture of surface-dominated food distribution, deep-water aggregations of C. pacificus californicus may support the mesopelagic community during periods of low food availability in surface waters.

Tannic acid, protein, and digestible carbohydrate: dietary imbalance and nutritional compensation in locusts'

Abstract: The combined effects of dietary imbalance and the allelochemical tannic acid on fifth stadium Locusta migratoria were investigated. In a factorial-design experiment, insects were fed artificial diets containing digestible carbohydrates and proteins in equal proportions (14 or 28%), or in a 1:2 or 2:1 ratio, with or without 10% tannic acid. Growth, consumption, and utilization efficiencies were measured over the course of the fifth stadium, and histological analyses of the midguts of newly molted adults were undertaken. While the consumption of diet was higher on the 14%-protein diets, consumption of protein remained lower than on the 28%-protein diets, indicating that compensatory feeding for protein was incomplete. Similarly, compensation for low dietary carbohydrates oc- curred, but was incomplete. Low levels of either nutrient resulted in increased intake of the other, but the effect of protein on carbohydrate intake was stronger than vice versa. There was a statistically interactive effect of carbohydrate and protein on the amounts of carbohydrate consumed, resulting from the fact that particularly high levels of carbohydrate were consumed when the diets simultaneously contained 28% carbohydrate and 14% pro- tein. The terms "incidental augmentation" and "incidental restriction" of intake are in- troduced to describe the ways that certain nutrient groups may affect the intake of others in foods that are nutritionally imbalanced. Tannic acid resulted in reduced efficiency of conversion of ingested nitrogen, but the efficiency of conversion of total ingested nutrients was higher on the diets containing tannic acid. A higher frequency of lesions was observed in the midgut epithelia of tannin-fed insects than controls, and it is suggested that the sloughing of necrotic epithelial tissues into the lumen and their subsequent egestion with the feces may account for the reduced efficiency of nitrogen conversion in these insects. A statistical interaction between protein levels and tannic acid demonstrated that tannic acid reduced consumption, but only of the low protein diets. Therefore, the effect of tannic acid was to restrict compensatory feeding for protein. A consequence of this was reduced growth in insects fed low-protein diets containing tannic acid. Total growth (dry mass) was lower on the 28%-protein diets and higher on the 28%- carbohydrate diets, and therefore corresponded with levels of carbohydrate intake. Nitrogen accumulation increased with dietary protein levels, but remained constant across carbo- hydrate levels despite increased intake of nitrogen on low-carbohydrate diets. This was accounted for by lower efficiency of conversion of nitrogen on the 14%-carbohydrate diets. Approximate digestibility was higher for the 1 4%-protein diets, possibly reflecting increased intake of easily digested carbohydrates. There were no statistically significant interactive effects between the two nutrients, or between either nutrient and tannic acid, on utilization efficiencies.

Apparent and true availability of amino acids from common feed ingredients for channel catfish.

Abstract: The apparent and true amino acid availability values for corn, wheat middlings, rice bran, rice mill feed, soybean meal, peanut meal, cottonseed meal, meat and bone meal, and two different samples of menhaden fish meal were determined in adult channel catfish. Although there was reasonable agreement between protein digestibility values and average amino acid availability values, individual amino acid availabilities were variable within and among the various feed ingredients tested. Therefore, we recommended that amino acid availability values should be used for more accurate catfish feed formulation. In addition, it appears that the use of true amino acid availability values should be used for feed ingredients of relatively low protein content.