The stimulation of yeast mitochondrial protein synthesis by low molecular weight cytoplasmic factors: Requirement for intact mitochondria and lack of effect by folate derivatives

• 1.1. Protein synthesis by GTP -supplemented yeast mitochondria is stimulated by a fraction of molecular weight less than 2,000 isolated from yeast high-speed supernatant (S-150).
• 2.2. The low molecular weight fraction works independently of the respiratory chain as the stimulation effect is not cyanide-sensitive.
• 3.3. Stimulation of mitochondrial protein synthesis by cytoplasmic factors is dependent upon the method of mitochondrial isolation.
• 4.4. The low molecular weight stimulatory factor(s) are not reduced folate derivatives which supply formyl groups required for initiation of mitochondrial protein synthesis.

     

Hydrolysis of glycol chitin by chitinolytic enzymes

• 1.1. The hydrolysis of glycol chitin preparations by several β-N-acetylglucosaminidases was monitored colorimetrically with the potassium ferriferrocyanide reagent.
• 2.2. Glycol chitin samples from crab and insect sources varied considerably in chemical composition and susceptibility to enzymatic hydrolysis.
• 3.3. Insect endochitinase preferred crab glycol chitin as substrate while hen's egg white lysozyme preferred commercial glycol chitin.
• 4.4. Insect glycol chitin was well hydrolyzed by both enzymes.
• 5.5. Insect exochitinase did not digest glycol chitin.

     

Beef liver glutamate dehydrogenase : Effects of partial proteolysis with chymotrypsin

• 1.1. After chymotryptic digestion of bovine glutamate dehydrogenase, the assay conditions determine whether activation or inhibition is observed.
• 2.2. The major fragments appear to remain physically associated.
• 3.3. Responses to both GTP and ADP are altered. Inhibition by GTP at pH 7 and 8 is almost abolished.
• 4.4. Out of various ligand combinations tested, GTP and NADH together provide the best protection against all the proteolytic effects.

     

Small membrane-associated gtp-binding proteins of catecholamine-secreting cells

• 1.1. Four GTP-binding proteins (23–27 kDa) were identified in membranes from PC12 cells by [α³²P]GTP binding to nitrocellulose blots of SDS-polyacrylamide gels.
• 2.2. The GTP-binding proteins remained associated with membranes during stimulation of intact cells by K⁺-depolarization or even after addition of C²⁺to digitonin-permeabilized cells.
• 3.3. By two-dimensional gel electrophoresis, six GTP-binding proteins were resolved and based on their mobility, their phosphorylation state appeared independent of Ca²⁺.
• 4.4. Fractionation of PC12 membranes showed that these GTP-binding proteins were broadly distributed in post-nuclear membranes with the plasma membranes containing the highest specific GTP-binding activity.
• 5.5. Membrane fractions from bovine adrenal medulla contain similar GTP-binding proteins with GTP-binding intensity also being highest in the plasma membrane.
• 6.6. The GTP-binding proteins could be concentrated in the detergent-rich fraction upon Triton X-114 phase separation.

     

Effects of niacin deficiency on the relative turnover rates of proteins in various tissues of Japanese quail

• 1.1. The effects of niacin deficiency on the relative turnover rates of proteins in various tissues of Japanese quail were investigated.
• 2.2. The level of liver NAD was not affected by niacin deficiency whereas the level of pectoral muscle NAD was markedly reduced.
• 3.3. In all dietary treatments the liver had the highest turnover rates of proteins, heart and brain had intermediate rates, and pectoral muscle had the lowest rates.
• 4.4. Relative turnover rates of proteins in all tissues (particularly pectoral muscle) of the niacin deficient group were significantly higher than those of pair-fed control group, although there were no significant differences in turnover rate between pair-fed control and control groups.
• 5.5. The high turnover rate of proteins in niacin deficiency was primarily attributed to enhanced degradation rate of proteins rather than enhanced synthesis rate of proteins.
• 6.6. Optical density scanning (or densitometric) of water-soluble pectoral muscle proteins separated by isoelectric focusing revealed several additional minor protein bands between major protein bands in the niacin deficient group which were more pronounced in the acidic region of the gel.
• 7.7. These results suggest that proteins with a low pI value in pectoral muscle of the niacin deficient animal are highly sensitive to protein degradation.

     

Physicochemical property of bovine brain 73-kDa stress protein

• 1.1. An approximately 70-kDa protein was purified from bovine brain using an ATP-Sepharose column.
• 2.2. The protein sample was found to contain two proteins (major 73 kDa and minor 72 kDa) on two-dimensional gel electrophoresis.
• 3.3. Antibodies raised against the 73- and 72-kDa proteins cross-reacted with stress-induced HSP73 and HSP72 from HeLa cells, respectively.
• 4.4. Heparin-binding peptides were obtained from trypsin digests of HSP73.

     

Neurochemical hypothesis: Participation by aluminum in producing critical mass of colocalized errors in brain leads to neurological disease

• 1.1. Aluminum is an established neurotoxin. Prolonged exposure to even low levels of aluminum permit its chelation and subsequent transport to brain where it is non-uniformly distributed.
• 2.2. Available evidence suggests that (i) aluminum interferes with glucose metabolism by inhibiting hexokinase and glucose-6-phosphate dehydrogenase; (ii) it binds to calmodulin and affects numerous phosphorylation-dephosphorylation reactions; (iii) it binds to transferrin and ferritin, affects the function of these proteins which in turn affect iron metabolism.
• 3.3. Thus accumulation of aluminum-induced metabolic errors colocalized in specific areas of the brain may lead to neurological disorders.

     

Pigment migration in fish erythrophores is controlled by alpha2-adrenoceptors

• 1.1. The aggregation of erythrosomes within erythrophores of the squirrel fish (Myripristis occidentalis; belonging to the family Holocentridae) was, on pharmacological grounds, shown to be mediated by alpha₂-adrenoceptors.
• 2.2. The erythrophores were shown to be controlled by adrenergic nerves activating the alpha₂-adrenoceptors.
• 3.3. The erythrophores themselves were found to possess a K⁺-sensitive mechanism of aggregation.
• 4.4. Some similarities and differences of the alpha₂-adrenoceptor-mediated chromatosome aggregation in melanophores and erythrophores are also discussed.

     

Purification and partial characterization of an AMP deaminase from the marine invertebrate Palaemon serratus

• 1.1. AMP deaminase from Palaemon serratus tail muscle was partially purified by chromatography on cellulose phosphate.
• 2.2. Muscle homogenates expressed very low enzyme activities and the presence of ATP was necessary to detect AMP deaminase. The specific activity and substrate affinity of the purified enzyme were also very low.
• 3.3. The purified prawn muscle AMP deaminase was contaminated by contractile proteins, one of the major contaminants being actin.
• 4.4. The enzyme displayed a very high affinity for actomyosin which was only partially abolished by pyrophosphate.

     

Identification of the major annexins in Ehrlich ascites tumor cells

• 1.1. Three calcium-binding proteins have been purified from Ehrlich ascites tumor cells.
• 2.2. They were identified by amino acid sequence analysis on selected fragments obtained by tryptic digestion.
• 3.3. The proteins belong to the annexin family and were identified as annexins II, III and V.
• 4.4. Antibodies raised against the proteins were used to examine for their presence in a number of murine tissues.
• 5.5. The occurrence was found to be in reasonable accordance with earlier reports.

     

The yolk polypeptides of a free-living rhabditid nematode

• 1.1. The yolk proteins of hermaphrodite Dolichorhabditis sp. (Nematode, Rhabditida) are composed of at least three polypeptides: VT1, VT2 and VT3 with molecular masses of 175.2, 107 and 82 kDa respectively.
• 2.2. All three yolk polypeptides make up at least one native protein complex which can be resolved by PAGE.
• 3.3. The yolk proteins are glycosylated and can be isolated by chromatography in Con A-Sepharose.
• 4.4. Partial chymotryptic hydrolysis shows that VT2 in different from its C. elegans homologue, YP115.
• 5.5. The main polypeptides synthesized by whole animals are the yolk components which are actively secreted in the incubation medium.

     

Stomach digestion and its effect upon protein hydrolysis in the intestine of rainbow trout (Salmo gairdneri Richardson)

• 1.1. The in vitro digestion of soya protein by pancreatic proteases of the trout was measured following various conditions of stomach digestion.
• 2.2. Peptic hydrolysis results in an increase of small peptides.
• 3.3. Acid treatment and peptic proteolysis do not affect the degradation of insoluble proteins or the formation of free amino acids during intestinal digestion, but they do lead to a significant shift from soluble polypeptides to di- and oligopeptides.

     

Isolation of crustacean egg yolk lipoproteins by differential density gradient ultracentrifugation

• 1.1. Egg yolk lipoproteins from four species of Crustacea were isolated by differential density gradient ultracentrifugation.
• 2.2. Egg yolk proteins from freshwater prawn, striped stone crab and mitten crab consissted of high-density lipoprotein (HDL) and lipid-free protein, while low-density lipoprotein (LDL) was present in the egg yolk protein of sand crayfish as well as HDL and lipid-free protein.
• 3.3. HDL was a major component in the egg yolk proteins from four species of Crustacea. HDL was identical to egg yolk lipovitellin.
• 4.4. Both HDL and LDL possessed phospholipid as a major lipid.
• 5.5. HDL, but not LDL, contained carotenoids. The color of HDL from mitten crab showed a reddish purple and was distinct from other Crustacea whose color was orange. The reddish purple color was characterized by an absorption flexion at 600–650 nm.

     

Hyaluronidase degradation of hyaluronic acid from different sources: Influence of the hydrolysis conditions on the production and the relative proportions of tetra- and hexasaccharide produced

• 1.1. Hyaluronic acid (HA) can be digested with a Streptomyces hyaluronidase.
• 2.2. The rate of production and the ratio of tetrasaccharide (T) and hexasaccharide (H), studied by HPLC, varied with the temperature and duration of hydrolysis.
• 3.3. The rates of production and the respective amounts of the two oligosaccharides depended on the rheological properties of the HA from different sources.
• 4.4. A close relationship was found between the initial rate of hydrolysis and the intrinsic viscosity of the HA (η_i).
• 5.5. Our data suggest that enzymatic degradation at a given pH value, temperature, and duration of hydrolysis is dependent on the conformation of HA.
• 6.6. Moreover, under given conditions, the relative proportions of the two oligosaccharides depend on the η_i and may also reflect the degree of hydrolysis of the substrate.

     

Alteration of the protein composition of bothrops jararaca venom and venom gland by isoproterenol treatment

• 1.1. The protein composition of Bothrops jararaca venom and venom gland was analyzed through SDS-PAGE, after isoproterenol (IPR) treatment.
• 2.2. Some proteins (47, 48, 57 and 72 kDa) were detected in the gland homogenate from the control but not from the IPR-treated samples.
• 3.3. Three proteins (26.5, 44.5 and 53 kDa) were detected in the venom gland from IPR-treated snakes but not from the venom gland from the control.
• 4.4. In the venom samples proteins of 41 and 74 kDa were detected only in the IPR treated samples, while proteins of 17 and 28 kDa were detected only in the control.
• 5.5. The biological activity of the venom did not change with IPR treatment.

     

Age-dependent proteins in eyes of annual killifishes Pterolebias longipinnis detected by 2-dimensional electrophoresis

• 1.1. Eye proteins of Pterolebias longipinnis have been analyzed by 2-dimensional isoelectric focusing SDS-polyacrylamide gel electrophoresis during aging from adolescence until normal death.
• 2.2. The protein pattern on the gels changed gradually with progressing age.
• 3.3. In senescent eyes, three protein spots appeared for a time and 36 disappeared from the pattern.
• 4.4. The isoelectric points of the proteins in the presence of urea and the molecular weights in an unreducing buffer are presented.

     

Proteomic Analysis of Baboon Cerebral Artery Reveals Potential Pathways of Damage by Prenatal Alcohol Exposure,

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Highlights

• •We studied mid-pregnancy alcohol exposure and baboon fetal cerebral artery.
• •238 proteins differed between control and alcohol-exposed fetuses near-term.
• •Proteins of metabolic pathways represented one of the major targets of alcohol.
• •Alcohol effect on the development of fetal brain vessels is persistent.

     

The effects of chronic metabolic acidosis on patterns of protein synthesis in rat renal cortex

• 1.1. In the rat chronic metabolic acidosis increases the net synthesis of 17 renal cortex proteins by amounts ranging from 1.5 to 4.5-fold.
• 2.2. These proteins have molecular weights between 13,000 and 42,000 and isoelectric points between approximately 5.5 and 7.0.
• 3.3. No new proteins not also present in normal animals are detected in renal cortex samples from acidotic animals.
• 4.4. Three proteins undergo substantial reductions in their net synthetic rates in chronic metabolic acidosis.
• 5.5. On the basis of their physical properties and similar alterations in net synthetic rate in acidosis some of these proteins appear to be closely related and may be coordinately expressed in the rat kidney.

     

Effect of lindane on phosphatidylinositol synthesis by cerebral cortex after acute and subchronic treatment

• 1.1. The incorporation of myo-[2-³H]inositol into phosphatidylinositols was unmodified in brain cortex miniprisms from convulsant rats.
• 2.2. However, the incorporation had increased by 300–400% in non convulsant rats which had received the same amount of lindane at a lower concentration.
• 3.3. This result suggests that phosphatidylinositols are implicated in the convulsion syndrome.
• 4.4. Experiments with lindane added in vitro were performed with both subchronically lindane intoxicated and untreated rats.
• 5.5. The results show an interesting lack of parallelism.
• 6.6. This might indicate the development of some resistance to the effects of lindane, possibly as the result of complex compensatory changes in inositol lipid biosynthesis.

     

Relationship between brain trehalase activity and trehalosema during direct and diapausing development in Pieris brassicae

• 1.1. Brain trehalase specific activity and trehalosemia were measured during the end of the developmental life cycle in non-diapausing and diapausing insects.
• 2.2. During non-diapausing development, trehalosemia reached maximum values at the beginning of pupal life. Then a constant decrease was observed up to the end of adult life.
• 3.3. The specific activity of brain trehalase was maximum when the insects were in active feeding periods, minimum activity appearing during moulting phases.
• 4.4. During diapausing development, trehalosemia was very high at the beginning of pupal life, particularly when insects were exposed to wintering conditions.
• 5.5. When diapause was broken, trehalosemia fell, announcing adult emergence.
• 6.6. Brain trehalase activity showed the same qualitative variations as in non-diapausing larvae, but with rather lower values.
• 7.7. During pupal life, brain trehalase activity decreased markedly during the long period necessary to obtain diapause breakdown.
• 8.8. Wintering conditions allow a progressive increase of brain trehalase activity, which preceded the fall of trehalosemia.