Phosphorylation of Escherichia coli proteins during the SOS response

• 1.1. The phosphorylation of Escherichia coli proteins was analyzed comparatively before and after induction of the SOS response in a temperature-sensitive mutant strain.
• 2.2. The presence of phosphorylated proteins was evidenced by gel electrophoresis and autoradiography after labelling with radioactive orthophosphate in vivo or radioactive adenosine triphosphate in vitro.
• 3.3. Significant changes in the intensity of protein labelling were observed upon induction of the SOS functions: six proteins were found to be more phosphorylated while two others were less phosphorylated. Moreover, five additional proteins appeared to become phosphorylated exclusively during the SOS response. The molecular mass and isoelectric point of these various proteins were determined.
• 4.4. For most proteins, the changes in the pattern of protein phosphorylation were concomitant with variations in the amount of protein synthesized.
• 5.5. The changes in the pattern of phosphoproteins observed during the SOS response were not due to the temperature shift required experimentally for expressing the SOS phenotype.
• 6.6. Phosphorylation was found to be catalyzed by protein kinases that modify amino acid residues at hydroxyl groups in protein substrates.
• 7.7. Both in vivo and in vitro studies brought evidence that neither RecA nor LexA, the two key regulatory proteins of the SOS functions, were capable of undergoing phosphorylation.

     

Chromatin proteins of rat preputial-gland: Acute changes in response to estrogen

• 1.1. The effects of estradiol-17β (E₂β) at 2 or 15min in vivo on chromatin proteins of rat preputial-gland were analyzed by a battery of electrophoretic methods.
• 2.2. Among histones, E₂β/control ratios for major bands of H1 decreased substantially between 2 and 15 min. In contrast, ratios of H4 increased (P < 0.01), whereas, except for losses by 2 min m a H2B-like component and in H3.1, other core histones were unchanged.
• 3.3. Among 0.35 M NaCl-soluble proteins, components at 34K-mol. wt and < 21K-mol wt were increased after 2 min of E₂β. The bulk of the hormone-responsive low-molecular weight proteins was basic in charge.
• 4.4. Electrophoretic correlates of 6 basic lysosomal proteins corresponded to those of low-molecular weight salt-soluble chromatin proteins.
• 5.5. Selective proteolysis initiated in vivo by E₂β depleted some tightly-bound nonhistone proteins.

     

Localization of α-tocopherol in hepatic chromatin from rats maintained on a tocopherol-deficient diet

• 1.1. A very significant amount of α-tocopherol was localized in hepatic chromatin when [³H]d-α-tocopherol was intravenously injected into rats maintained on tocopherol-deficient diet.
• 2.2. The site of association of α-tocopherol in the intrachromatin domain was examined by several methods.
• 3.3. The results show that α-tocopherol is predominantly localized in the heterochromatin and is associated with proteins exhibiting the characteristics of nonhistone proteins that have very high affinity for DNA.

     

Vitellogenesis in the stable fly,stomoxys calcitrans

• 1.1. No female specific proteins were found in the stable fly hemolymph by polyacrylamide gel electrophoresis.
• 2.2. Six major yolk polypeptides (YP1, YP2, YP3, YP4, YP5 and YP6) have been identified in the stable fly. Their mol. wt as determined by SDS-polyacrylamide gel electrophoresis are 41,100, 42,600, 44,100, 46,600, 48,900 and 50,600, respectively.
• 3.3. YP3 was purified and antibody made against it. By using the antibody and in vitro organ culture the stable fly yolk polypeptides were shown to be synthesized exclusively by the ovaries and not the fat body.
• 4.4. The stable fly yolk polypeptides are immunologically similar to yolk proteins of other related flies.

     

Stress-induced heat-shock protein synthesis in peripheral leukocytes of turkeys,Meleagris gallopavo

• 1.1. Thermal stress, in vitro and in vivo, induced the synthesis of heat-shock proteins, HSP90, HSP70, and HSP23 in turkey leukocytes.
• 2.2. HSP induction was both temperature- and time-dependent.
• 3.3. Salinity-specific stress proteins were expressed with elevated osmolality in culture medium.

     

Larval Musca domestica lipophorin biosynthesis

• 1.1. Larval Musca domestica lipophorin biosynthesis was studied in vitro.
• 2.2. The newly synthesized lipophorin has a density a little lower than the circulating lipophorin after 1 hr of incubation. After 3 hr of incubation the fat body cells transfer lipids to the lipophorin that attains the density of circulating lipophorin.
• 3.3. The lipophorin synthesized in vitro is identical to circulating lipophorin in density and in electrophoretical behavior.
• 4.4. However these two molecules must have differences since the circulating lipophorin transfers lipids to fat body cells while the synthesized in vitro does not.
• 5.5. The biosynthesis of Musca lipophorin shows differences with the Manduca sexta lipophorin biosynthesis.

     

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.

     

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.

     

A comparative study of the basic nuclear proteins from sperm of bivalve molluscs

• 1.1. Basic nuclear proteins from spermatozoa of the three mollusc species belonging to the class Bivalvia have been analyzed using one- and two-dimensional electrophoresis.
• 2.2. Four nuclear basic proteins have been purified and their amino acid compositions determined.
• 3.3. In these spermatozoa histone-type proteins coexist with protamine-like proteins.
• 4.4. The protamine-like proteins that have been studied show different electrophoretic behavior but in general are similar, with a high content of lysine, arginine, alanine and serine.
• 5.5. Interspecific variability has been found for the H1-like histone.

     

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.

     

Changes in the activities of lysosomal enzymes in the fat body and midgut of two lepidopteran insects (Mamestra brassicae and Pieris brassicae) during metamorphosis

• 1.1. The activities of three lysosomal enzymes (acid phosphatase, β-galactosidase, catepsin D) was observed during metamorphosis in the fat body and midgut cells of two insects (Mamestra brassicae and Pieris brassicae).
• 2.2. The activities increased slightly during the feeding period and showed a sharp rise at the beginning of the wandering period.
• 3.3. Subsequently, a decrease was observed during the pre-pupal stage and pupation.
• 4.4. The activities increased again 2 days after the larval-pupal moult.
• 5.5. We suggest that an inhibitory mechanism works in the studied cells before pupation to protect the stored proteins from the degradation until the beginning of differentiation of imaginai cells in the pupal stage.

     

Induction kinetics of immune antibacterial proteins in pupae of Galleria mellonella and Pieris brassicae

• 1.1. Pupae of Galleria mellonella and Pieris brassicae given an injection with live, non-pathogenic Enterobacter cloacae or abiotic foreign molecules induce an acquired immunity that corresponds with the synthesis of haemolymph proteins of antibacterial activity.
• 2.2. This humoral defensive response which persists for several days, differs quantitatively between insect species and between the inducers used, although very different foreign bodies induced the same immune proteins in both lepidopteran insects.
• 3.3. A stronger and longer lasting response was consistently noticed in pupae immunized with non-pathogenic bacterium than after sterile nutrient broth injections.
• 4.4. A demonstrably elevated activity of haemolymph lysozyme and trace activity of cecropins found in pupae of Galleria treated with saline W, a salt solution physiological to moths, disappear soon after 36 hr from injection.
• 5.5. In P. brassicae, however, sterile insect Ringer can give a varying, if present at all, immune response.
• 6.6. A mechanical injury (sterile wounding of insect body) can occasionally induce a similar but much weaker response.
• 7.7. The antibacterial activity was drastically reduced in Pieris or completely depressed in most pupae of Galleria when actinomycin D or cycloheximide was given at an early time post-immunization with E. cloacae.
• 8.8. It is concluded that the de novo synthesis of ribonucleic acid and immune proteins is required for expression of antibacterial activity in pupal haemolymphs.
• 9.9. The synthesis of an immune mRNA was completed about 7 hr after the injection of the immunizing bacteria.

     

Heterosynthetic origin of the major yolk protein,vitellin, in a nereid,Perinereis cultrifera (polychaete annelid)

• 1.1. An examination of proteins synthesized by Perinereis cultrifera oocytes incubated in vitro with [³H]leucine clearly shows that these cells are not capable of synthesizing the main yolk protein previously identified in this worm.
• 2.2. In addition, the detection of radiolabelled vitellin in oocytes after in vitro incubation of an oocyte-coelomocyte cell mixture in presence of [³H]leucine strongly suggests that the coelomocytes, free cells in the coelomic cavity, synthesize and secrete a vitellin precursor, vitellogenin, that is subsequently taken up by the oocytes.
• 3.3. Two native proteins differing in mol. wt but reacting with anti-vitellin antibodies have been identified in coelomocyte incubation medium. Also found in the coelomic fluid, they have been designated VG1 (M_r = 530,000) and VG2 (M_r = 320,000).
• 4.4. The two vitellogenins consist of a single type of polypeptide of M_r = 176,000 and are incorporated in the oocytes where they are apparently observed under a single molecular form corresponding to VG1, the highest mol. wt protein similar in size to the initial form of vitellin (VI, 530,000).
• 5.5. From these data, it seems likely that VG2 is a monomeric molecule that is taken up by the oocytes as a dimer of VG1.
• 6.6. We conclude that P. cultrifera accumulates vitellin heterosynthetically and that vitellogenin is produced by the coelomocytes. Moreover, a single polypeptide similar in size to the polypeptidic component of secreted vitellogenin has been detected in the coelomocytes.
• 7.7. Since this polypeptide has been identified previously as the single intraoocytic precursor of the four lower mol. wt products that make up the mature form of vitellin (V5), it appears that P. cultrifera exhibits for vitellogenin a processing pathway in which cleavage of the precursor occurs only after uptake by the oocyte.

     

Main kinetic characteristics of acetylcholinesterase from brain of Hypostomus punctatus,a Brazilian bentonic fish (cascudo)

• 1.1. A potentiometric method for the assay of cholinesterase has been proposed and compared with a colorimetric assay.
• 2.2. Main kinetic parameters of cholinesterase from Hypostomus punctatus brain were determined indicating that true acetylcholinesterase is by far the predominant enzyme in the brain of this fish.
• 3.3. We have compared our data with published results described from other fish species.
• 4.4. The enzyme inhibition achieved after 3 hr incubation of brain homogenates with ethyl-parathion have indicated that this enzyme shows a characteristic organophosphorous sensitive behavior.

     

The Proteome of Pig Spermatozoa Is Remodeled During Ejaculation

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Highlights

• •Proteome of mature boar spermatozoa from cauda epididymal and ejaculated sources were analyzed by iTRAQ-based LC-MS/MS.
• •1,723 sperm proteins identified (974 of Sus scrofa taxonomy).
• •1,602 sperm proteins quantified (960 of Sus scrofa taxonomy).
• •32 Sus scrofa sperm proteins were differentially expressed among sperm sources.
• •The proteome of boar spermatozoa is remodelled during ejaculation.

     

A quantitative method for analysis of radiolabelled proteoglycans synthesized by cultured human arterial smooth muscle cells

• 1.1. Sulphate labelled proteoglycans (PG) synthesized by cultured human arterial smooth muscle cell have been quantified using an improved method based on a combination of specific enzymes and ethanol precipitation.
• 2.2. The present method gives quantitative data of PGs and subclasses allowing batchwise analysis of a large number of samples.
• 3.3. Approximately 81 % ± 1.7% (mean ± SD, n = 6) of total PGs synthesized by human arterial smooth muscle cells accumulated in medium.
• 4.4. In cell layer and medium chondroitin sulphate proteoglycan constituted 65.0% ± 0.3% and 75.8% ± 0.7% (mean ± SD, n = 3), respectively of sulphated PGs.
• 5.5. Heparan sulphate proteoglycan accounted for 26.8% ± 0.6% in cell layer and 22.6% ± 0.5% (mean ± SD, n = 3) in medium of sulphated PGs.

     

Characterization of proteolytic activities stimulated by SDS or urea and two-dimensional gel electrophoresis of proteins from Brachionus plicatilis (Rotifera)

• 1.1. Proteinases occurring in the 27,000 g supernatant of homogenates from Brachionus plicatilis have been characterized by electrophoretic techniques.
• 2.2. Several individual proteases were detected which are active in the presence of either SDS or urea.
• 3.3. By applying this knowledge about the properties of proteases occurring in Brachionus, two-dimensional electrophoretic separations of proteins from Brachionus plicatilis are made feasible without proteolytic artifacts.

     

Serum chemistry profiles for Lechwe waterbucks (Kobus leche): Variations with age and sex

• 1.1. Over an 8-year period, 19 biochemical parameters have been determined at various ages in the blood serum of 92 clinically healthy Lechwe waterbucks (Kobus leche), 33 males and 59 females.
• 2.2. Significant differences have been noted with age. In neonates, the lowest values of total proteins, glucose, creatinine, urea, AST, ALT and iron have been noted; the highest ones have been seen for cholesterol, alkaline phosphatase, calcium and phosphorus.
• 3.3. With regard to sex, raised values of glucose, urea, alkaline phosphatase and ALT, and lowered values of cholesterol, have been noted in juvenile females compared with males of the same age.
• 4.4. In adult females, higher levels of urea and cholesterol and lower levels of glucose, triglycerides and natrium have been recorded compared with males.
• 5.5. With sex and age, no significant changes have been found in the levels of GGT, magnesium, chlorides and copper.
• 6.6. Out findings are discussed with those abstracted from the literature for related species.

     

In vitro non-enzymatic glycosylation of myofibrillar proteins

• 1.1. Glycation is non-enzymatic modification of proteins by sugars in which not only structural but also biological properties of proteins are altered.
• 2.2. Our in vitro experiments show that incubation of myofibrillar proteins with ribose results in sugar attachment to proteins and at the same time myofibrillar ATPase activity is lowered.
• 3.3. DETAPAC, aminoguanidine and 2-mercaptoethanol all partially block myofibrillar protein glycation and ATPase activity is less inactivated.
• 4.4. The dependence of ATPase activity of myofibrils incubated with ribose on the amount of 2-mercaptoethanol present suggests that also modification of SH groups is involved in enzyme inactivation.
• 5.5. Electrophoretic studies revealed that heavy chains of myosin, actin, and tropomyosins are proteins which are mainly glycated in vitro.