Replacement of a labile aspartyl residue increases the stability of human epidermal growth factor

Long-term storage of recombinant human epidermal growth factor (EGF), an important promoter of cell division, results in its conversion to a new species that elutes later than native EGF on a reverse-phase column. This new species, called EGF-X, has only 20% of the biological activity of native EGF. Peptide mapping indicated that the primary structure of EGF-X differs from that of native EGF solely within the first 13 residues. N-Terminal sequencing of EGF-X revealed that about 30% of the polypeptides have been cleaved at the Asp-3/Ser-4 bond. In addition, the yields after the His residue at position 10 were extremely low, indicating that a chemical modification occurs at residue 11 that is incompatible with Edman degradation. We hypothesized that aspartic acid 11 had been converted to an isoaspartyl residue, and this was confirmed with L-isoaspartyl/D-aspartyl methyltransferase, an enzyme that methylates the side-chain carboxyl group of L-isoaspartyl residues but does not recognize normal L-aspartyl residues. EGF-X, but not EGF, was found to be a substrate of this enzyme, and proteolytic digestion of EGF-X with thermolysin localized the site of methylation to a nine-residue peptide containing position 11. We did not observe formation of the isoaspartyl derivative in EGF that had been denatured by reduction of its disulfide bonds. In addition, replacement of the aspartyl residue at position 11 with glutamic acid resulted in a fully active EGF derivative that does not form detectable amounts of EGF-X. We propose that conversion of this aspartyl residue to isoaspartate is a significant nonenzymatic degradation reaction affecting this growth factor.(ABSTRACT TRUNCATED AT 250 WORDS)

[Speech outcome after early or delayed hard palate closure]

Delayed hard palate closure (after age 6-7) was widely used for palatal repair in cleft palate children from 1976 to 1982. Since 1982, the approach has been revised into early complete closure of the soft and hard palate (before age 2). The articulation skills of 60 children with cleft lip and palate (age 3-5:11) who underwent early complete palate closure were compared with 47 children of similar age with soft palate closure only. The results indicated that the early complete closure group had more children with adequate articulation skills than the delayed hard palate closure group. Detailed analysis of the articulation patterns in each group revealed that the articulation substitution patterns made by the early complete closure group followed the trends of developmental articulation patterns, i.e. unaspirated, stopping and fronting phonological features. On the contrary, the articulation substitution patterns made by the delayed hard palate closure group were more related to structural deficits, i.e. compensatory articulation. Age 3-5 is a critical period for articulation maturation. We advocate that the complete palatal closure should be achieved before age 2 in order to equip cleft palate children with an equally normal oral structures to enhance speech/language development in a normal learning process during this critical period.

Inducible expression of cytokinin biosynthesis in Agrobacterium tumefaciens by plant phenolics

Nopaline strains of Agrobacterium tumefaciens contain a gene, tzs, that encodes a cytokinin biosynthetic prenyl transferase. The gene is located adjacent to the Ti plasmid virulence region and is constitutively expressed at low levels. As a result, bacteria containing tzs secrete low levels of zeatin into the medium. We find zeatin secretion to be induced more than 100-fold by acetosyringone, one of a number of naturally occurring phenolics produced by plants in response to wounding. Induction was very sensitive to the pH of the medium (optimum pH 5.5) and was due to massive overexpression of tzs-encoded cytokinin prenyl transferase activity. The relative ability of members of a set of phenols to induce tzs expression was examined and found to be parallel to that reported for activation of other virulence genes. A series of molecular cloning experiments established that virA and virG, two genes known to be essential to the virulence induction process, were necessary and sufficient for phenolic-induced tzs expression. Sequences present in the promoter region of tzs were found to be similar to those present in genes regulated by bacterial two-component positive regulatory systems.

Reimmunization of children immunized at 18 months of age with Haemophilus influenzae type b vaccine

We studied the response to reimmunization at 36 months of age with Haemophilus influenzae type b (Hib) polyribosylribitol phosphate (PRP) capsular polysaccharide vaccine. Children enrolled in the study had previously received PRP or PRP plus diphtheria and tetanus toxoids with pertussis vaccine at 18 months of age. A control group of children, who received a first dose at 36 months of age, was also studied. Ninety-five percent of children receiving a second dose of vaccine had a postimmunization anti-capsular antibody level of greater than or equal to 1 microgram/mL. In comparison, 70% of 36-month-old children who received their first dose of PRP had a postimmunization level greater than or equal to 1 microgram/mL (P = 0.09). The geometric mean titer at 37 months of age was 8.64 micrograms/mL in children who had received two doses of PRP vaccine, compared with 2.19 micrograms/mL in the group who received only one dose of PRP at 36 months of age (P = 0.04). We conclude that infants immunized at 17 to 19 months of age with PRP had an excellent immunologic response to reimmunization at 36 months of age.

Development of articulation before delayed hard-palate closure in children with cleft palate: a cross-sectional study

The development of articulation before surgical closure of the hard palate was compared in 75 preschool children with cleft lip and palate and 40 preschool children born without clefts. The children were aged 2 years to 5 years 11 months. The patients had significantly poorer articulation skills than the controls at each age level. Substitutions were the most frequent error, and they did not decrease with age in the patients. Fistula size and a history of speech therapy were significant factors in the articulation error scores only in 5-year-olds. No advantage in articulation proficiency was found for those who had worn a prosthesis to occlude the hard-palate defect.

Translocation of oncogene c-sis from chromosome 22 to chromosome 17 in a human myelogenous leukemia cell line

By combining somatic cell genetics, in situ hybridization and Southern hybridization, we found that the c-sis oncogene in the human myelogenous leukemia cell line ML3 is translocated from the long arm (q11----qter) of chromosome 22 to the long arm (mid-portion or q21 region) of chromosome 17. This translocation does not result in rearrangement of the c-sis oncogene.

Characterization of lens crystallins and their mRNA from the carp lenses

Crystallins from carp eye lenses have been isolated and characterized by gel permeation chromatography, SDS-gel electrophoresis, immunodiffusion and amino acid analysis. gamma-Crystallin is the most abundant class of crystallins and constitutes over 55% of the total lens cytoplasmic proteins. It is immunologically distinct from the alpha- and beta-crystallins isolated from the same lens and its antiserum shows a very weak cross-reaction to total pig lens antigens. Comparison of the amino acid compositions of carp gamma-crystallin with those of bovine gamma-II, haddock gamma- and squid crystallins indicates that gamma-crystallin from the carp is very closely related to that of the haddock, and probably also related to the invertebrate squid crystallin. In vitro translation of total mRNAs isolated from carp lenses confirms the predominant existence of gamma-crystallin. The genomic characterization of carp crystallin genes should provide some insight into the mechanism of crystallin evolution in general.

Biochemical comparison of epsilon [correction of gamma]-crystallins from duck and frog eye lenses

A biochemical comparison has been made on the crystallins isolated from duck and frog lenses. Gel-permeation chromatography of lens homogenates from both classes on Fractogel TSK HW-55(S) revealed a homogeneous trimeric protein of 120 kDa in the duck lenses and a monomeric protein of 39 kDa in the frog lenses. Both crystallin fractions consist only of an approx. 38-kDa polypeptide in their subunit structures as determined by SDS gel electrophoresis. These two crystallins were compared with respect to their native molecular masses, subunit structures, peptide mapping and amino acid compositions in order to establish the identity of each crystallin. We have found differences in the protein structures of these two crystallins despite some degree of similarity in their amino acid compositions.

The extrafloral nectaries of cowpea (Vigna unguiculata (L.) Walp): I. Morphology, anatomy and fine structure

The cowpea bears two distinctive types of extrafloral nectaries. One, on the stipels of trifoliolate leaves, consists of a loosely demarcated abaxial area (1-2 mm diameter) of widely-spaced trichomes (papillae) borne on a stomata-free epidermis, and lacking a specific vascular supply. Each trichome has up to eight apical (head) cells, two to four intermediate cells, and a single large stalk cell. The secretory faces of the apical cells bear wall ingrowths and an easily detached cuticle. The wall separating the stalk cell and the underlying epidermal cell(s) has a mean plamodesmatal frequency of 25/μm(2). The second type of nectary consists of a large elliptical mound of tissue (short and long axes about 2 mm and 4 mm) formed between a pair of flowers on an inflorescence stalk. It comprises four to eight cone-shaped subnits of secretory tissue, each with a circular secretory orifice and an individual supply of phloem, but not of xylem. Cells of the secretory tissue of the nectary subunits separate as they mature, and nectar flows to the orifice through the resulting intercellular spaces. Intact secretory cells and cellular debris are extruded into the nectar. Some of the sieve elements terminating in the inner secretory tissue exhibit open sieve pores. Each mature secretory cell contains many small (2 μm diameter) spherical protein bodies and one to three large (up to 2-3 μm diameter 15 μm long), paracrystalline bodies. These inclusions are absent or not fully developed in inner, less mature regions of the secretory tissue. Mechanisms of secretion are proposed for the two classes of nectary, including estimates of flux of sugar into the trichomes of the stipel nectary.

Diurnal water balance of the cowpea fruit

The vascular network of the cowpea (Vigna unguiculata [L.] Walp.) fruit exhibits the anatomical potential for reversible xylem flow between seeds, pod, and parent plant. Feeding of cut shoots with the apoplast marker acid fuchsin showed that fruits imported regularly via xylem at night, less frequently in early morning, and only rarely in the afternoon. The dye never entered seeds or inner dorsal pod strands connecting directly to seeds. Root feeding (early morning) of intact plants with (32)PO(4) or (3)H(2)O rapidly (20 min) labeled pod walls but not seeds, consistent with uptake through xylem. Weak subsequent (4 hours) labeling of seeds suggested slow secondary exchange of label with the phloem stream to the fruit. Vein flap feeding of subtending leaves with [(14)C]sucrose, (3)H(2)O, and (32)PO(4) labeled pod and seed intensely, indicating mass flow in phloem to the fruit. Over 90% of the (14)C and (3)H of fruit cryopuncture phloem sap was as sucrose and water, respectively. Specific (3)H activities of transpired water collected from fruits and peduncles were assayed over 4 days after feeding (3)H(2)O to roots, via leaf flaps, or directly to fruits. The data indicated that fruits transpired relatively less xylem-derived (apoplastic) water than did peduncles, that fruit and peduncle relied more heavily on phloem-derived (symplastic) water for transpiration in the day than at night, and that water diffusing back from the fruit was utilized in peduncle transpiration, especially during the day. The data collectively support the hypothesis of a diurnally reversing xylem flow between developing fruit and plant.

Nitrogen nutrition and the development and senescence of nodules on cowpea seedlings

Cowpea (Vigna unguiculata (L.) Walp cv. Vita 3) seedlings inoculated with Rhizobium strain CB756 were cultured with their root systems maintained in air or in Ar: O2 (80:20, v/v) during early nodule development (up to 24 d after sowing). Compared with those in air, seedlings in Ar:O2 showed progressive N deficiency with inhibited shoot growth, reduced ribulose-1,5-bisphosphate carboxylase and total protein levels and loss of chlorophyll in the leaves. Nodule initiation, differentiation of infected and uninfected nodule tissues and the ultrastructure of bacteriod-containing cells were similar in the air and Ar: O2 treatments up to 16 d after sowing. Thereafter the Ar: O2 treatment caused cessation of growth and development of nodules, reduced protein levels in bacteroids and nodule plant cells, and progressive degeneration of nodule ultrastructure leading to premature senescence of these organs. Provision of NO 3 (-) (0.1-0.2 mM) to Ar: O2-grown seedlings overcame the abovementioned consequences of N2 deficiency on nodule and plant growth, but merely delayed the degenerative effects of Ar: O2 treatment on nodule structure and senescence. Treatment of Ar: O2-grown seedlings with NO 3 (-) greatly increased the protein level of nodules but the increase was largely restricted to the plant cell fraction as opposed to the bacteroids. By contrast, NO 3 (-) treatment of air-grown seedlings increased protein of bacteroid and host nodule fractions to the same relative extents when compared with air-grown plants not supplemented with NO 3 (-) . These findings, taken together with studies of the distribution of N in nodules of symbiotically effective plants grown from (15)N-labeled seed, indicate that direct incorporation of fixation products by bacteroids may be a critical feature in the establishment and continued growth of an effective symbiosis in the cowpea seedling.

A minimum of four human class II alpha-chain genes are encoded in the HLA region of chromosome 6

The major histocompatibility complex (MHC) in man, also called the HLA region, is located on the short arm of chromosome 6 and encodes antigens involved in immunological processes. The class II HLA antigens consist of two noncovalently associated polypeptide chains, one of molecular weight 34,000 (alpha) and the other of molecular weight 29,000 (beta). The extensive polymorphism of the beta chain(s) has allowed the genetic mapping of the corresponding beta gene(s) to the HLA-DR region. cDNA clones for the HLA-DR alpha chain have been used to map the non-polymorphic DR alpha-chain gene to chromosome 6 using mouse-human somatic cell hybrids. Similarly, the DR alpha-chain gene has been mapped to the short arm of chromosome 6 centromeric to the HLA-A, -B and -C loci by in situ hybridization experiments. We isolated a cDNA clone that is related to the DR alpha chain and encodes the class II antigen DC alpha chain. We describe here how this DC alpha clone was used to find two or three additional alpha-chain genes by cross-hybridization and how HLA-antigen loss mutants of a human lymphoblastoid cell line (LCL) were used to ascertain that these additional class II antigen alpha-chain genes are also located in the HLA region.

Results of the Widmaier-Perko palatoplasty in clefts of secondary palate

The Widmaier-Perko palatoplasty was evaluated in post alveolar clefts. The speech results of 42 Chinese patients revealed 78.5% as having acceptable speech. In post alveolar clefts of the soft palate only 80% had acceptable speech compared to 76% acceptable speech for clefts of the soft and hard palate. This compared favourably with other similar reported studies. No dental occlusal or growth disturbances were noted. There was significant middle ear disease in the patients examined. This type of palatoplasty does not disturb the palatine bone periosteum and may be helpful in preventing growth disturbances.

Duration of maternally derived immunity to tetanus and response in newborn foals given tetanus antitoxin

Serum tetanus antitoxin (TAT) concentrations were measured in a group of 30 foals from birth to 4 months of age. Five of 30 foals (16.6%) had serum titers less than 0.01 IU of TAT/ml by 1 month of age. At 2 months of age, 17 of 28 foals (60.7%) had titers less than 0.01 IU/ml. By 3 months of age, 22 of 29 (75.5%) foals tested had titers of less than 0.01 IU/ml. At the age of 4 months, 24 of 29 foals (82.1%) had titers of less than 0.01 IU/ml. The TAT given to foals at birth resulted in an immediate increase in titer when circulating antitoxin was absent or minimal. Titers considered protective against tetanus resulting from an IM injection of exogenous TAT at birth were maintained for at least 3 months after the injection.

Forming and removing stain precipitates on ultrathin sections

Stain precipitates resulting from the use of lead or uranyl salts, or both, on ultrathin sections can be classified as belonging to one of three morphological types: I) extremely electron-dense particles caused by prolonged use of lead salts only, II) amorphous networks formed following double staining with either aqueous or alcoholic uranyl and lead salts, and III) crystalline needles sometimes resulting from double staining with alcoholic uranyl and lead salts. It has been found, however, that either acetic acid or aqueous uranyl acetate can be used to remove type I and type II precipitates from sections, and that oxalic acid and alcoholic uranyl solution will remove type II precipitates. Unfortunately, type III precipitates are unaffected by any agents tested so far.

A simple method for removing stain precipitates from biological sections for transmission electron microscopy

Stain precipitates originating from either lead salt or double staining with uranyl acetate and lead citrate on ultrathin sections of biological material can be removed by using 10% aqueous glacial acetic acid.

Initital cellularization and differentiation of the aleurone cells in the ventral region of the developing wheat grain

Early cellularization of the free-nuclear endosperm and subsequent differentation of the aleurone cells in the ventral region of the developing wheatgrain (Triticumaestivum L. cv. Heron) were examined using both light and electron microscopy. In ovules harvested 1 d after anthesis, irregular wall ingroths typical of transfer cells protrude into the multinucleate cytoplasm. Initital cellularization occurs by a process of free wall formation in much the same fashion as in the dorsal region of the grain. In places, sheets of endoplasmic reticulum and dictyosomes appear to be closely associated with the growing wall. Like the wall ingrowths noted earlier, the freely growing walls are intensely fluorescent after staining with aniline blue. Initiatal cellularization is complete 2-3 days after anthesis. Unlike the first-formed cells in the dorsal region of the developing grain, those in the ventral region are not meristematic. These amitotic cells become the groove aleurone cells which at an early stage of development are set apart from the rest of the endosperm by their irregularly thickened walls and dense cytoplasm. Autofluorescence is first apparent in the walls of those cells next to the degenerating nucellus. In contrast to the aleurone cells in the dorsal region of the grain, at maturity only the inner wall layer of each of the groove aleurone cells remains autofluorescent. The aleurone grains are highly variable in appearance and contain no Type II inclusions.

Comparison of the bronchodilator effects of aerosol fenoterol and isoproterenol

Aerosolized fenoterol in a dosage of 400 microgram was compared to isoproterenol 150 microgram in 31 asthmatic subjects during the course of a double-blind parallel 90-day study. Bronchodilator activities of the two drugs were evaluated for up to 6 hours on days 1, 45 and 90. Analysis of the data revealed that fenoterol consistently produced a significantly greater increase in FEV1, FEF25-75% and Gaw/VL. Specific airway conductance increased on each test day 25 percent or more above baseline for over three hours after use of fenoterol and for only one hour after use of isoproterenol. Fenoterol has less effect upon the cardiovascular and central nervous systems, but produced a greater incidence of shaking compared to isoproterenol. Patients used fenoterol less frequently than isoproterenol which can be attributed to the former having a greater peak effect and time course of bronchodilation. The therapeutic efficacy of fenoterol was sustained throughout this three-month study, and suggests that this relatively selective beta2 adrenergic drug will provide a well tolerated, alternative aerosol for chronic use in asthma.

Photosynthetic Pod Wall of Pea (Pisum sativum L.): Distribution of Carbon Dioxide-fixing Enzymes in Relation to Pod Structure

The pod wall of pea (Pisum sativum L.) was shown to contain two distinct photosynthetic layers. The outer, comprising chlorenchyma of the mesocarp, captured CO(2) from the outside atmosphere; the inner, a chloroplast-containing epidermis lining the pod gas cavity, was involved in photoassimilation of the CO(2) released from respiring seeds.Structural features of the pod included the thick cuticle and stomata of the outer epidermis, the inward projecting veinlets of the vascular network in the mesocarp, the sparsity of air spaces, the fiber and parenchyma layers of the endocarp, and the abundant chloroplasts, thin cuticle, and rounded outer contours of cells of the inner epidermis.The inner epidermis showed high specific activities of ribulose 1,5-diphosphate (RuDP) carboxylase (EC 4.1.1.39) and phosphoenolpyruvate (PEP) carboxylase (EC 4.1.1.31), contained up to 20% of the pod's chlorophyll, and was capable of fixing 66% of the CO(2) released during the photoperiod to the pod gas space by the seeds of a fully grown fruit.The in vitro carboxylation capacity of the pod exceeded the estimated gross photosynthesis of the fruit for all but the last few days of development. Chlorophyll content and carboxylation activity declined more markedly in the outer photosynthetic layers than in the inner epidermis.The ratio of activities of RuDP carboxylase to PEP carboxylase in pod extracts varied from 2.4:1 to 12:1 as against 48:1 to 156:1 in extracts of leaves.Structural and physiological properties of the pod were related to its capacity to conserve respired CO(2) and provide photosynthate to developing seeds.