Structural cell-wall proteins in protoxylem development: evidence for a repair process mediated by a glycine-rich protein

Polyclonal antibodies were used to localize structural cell-wall proteins in differentiating protoxylem elements in etiolated bean and soybean hypocotyls at the light- and electron-microscopic level. A proline-rich protein was localized in the lignified secondary walls, but not in the primary walls of protoxylem elements, which remain unlignified, as shown with lignin-specific antibodies. Secretion of the proline-rich protein was observed during lignification in different cell types. A glycine-rich protein (GRP1.8) was specifically localized in the modified primary walls of mature protoxylem elements and in cell corners between xylem elements and xylem parenchyma cells. The protein was secreted by Golgi bodies both in protoxylem cells after the lignification of their secondary walls and in the surrounding xylem parenchyma cells. The modified primary walls of protoxylem elements were visualized under the light microscope as filaments or sheets staining distinctly with the protein stain Coomassie blue. Electron micrographs of these walls show that they are composed of an amorphous material of moderate electron-density and of polysaccharide microfibrils. These materials form a three-dimensional network, interconnecting the ring- or spiral-shaped secondary wall thickenings of protoxylem elements and xylem parenchyma cells. The results demonstrate that the modified primary walls of protoxylem cells are not simply breakdown products due to partial hydrolysis and passive elongation, as believed until now. Extensive repair processes produce cell walls with unique staining properties. It is concluded that these walls are unusually rich in protein and therefore have special chemical and physical properties.     

Sequence of a cDNA for mouse thymidylate synthase reveals striking similarity with the prokaryotic enzyme

We report the nucleotide sequence of a cloned cDNA, pMTS-3, that contains a 1-kb insert corresponding to mouse thymidylate synthase (E.C. 2.1.1.45). The open reading frame of 921 nucleotides from the first AUG to the termination codon specifies a protein with a molecular mass of 34,962 daltons. The predicted amino acid sequence is 90% identical with that of the human enzyme. The mouse sequence also has an extremely high degree of similarity (as much as 55% identity) with prokaryotic thymidylate synthase sequences, indicating that thymidylate synthase is among the most highly conserved proteins studied to date. The similarity is especially pronounced (as much as 80% identity) in the 44-amino-acid region encompassing the binding site for deoxyuridylic acid. The cDNA sequence also suggests that mouse thymidylate synthase mRNA lacks a 3' untranslated region, since the termination codon, UAA, is followed immediately by a poly(A) segment.      

Regulation of hepatic glycogenolysis by glucagon in male and female rats. Role of cAMP and Ca2+ and interactions between epinephrine and glucagon

The effects of 10(-10) to 10(-7) M glucagon on cAMP, phosphorylase a, cell calcium, and glucose production, and glucagon interactions with epinephrine were studied in isolated hepatocytes from adult male and female rats. At physiological concentrations (10(-10) - 10(-9) M), glucagon activated phosphorylase by increasing cAMP and not by raising the cytosolic free calcium. At supra-physiologic concentrations (and in the male only), glucagon slightly increased the cytosolic free calcium, the fractional efflux of calcium, and, after 2 h, decreased the cell calcium content. Exposure of hepatocytes to the simultaneous administration of 10(-9) M glucagon and 10(-7) M epinephrine resulted in a prolongation of the activation of phosphorylase a and a greater release of glucose from glycogen stores than exposure to either agonist alone. In the male, the effects of low concentrations of the two hormones on phosphorylase a activity were additive. Cytosolic free calcium was increased by 10(-6) M epinephrine from 280 to 500 nM while physiological concentrations of glucagon did not change it. In these intact cells, there was no evidence of an alpha 2-adrenergic inhibition of adenyl cyclase and no indication that cAMP depresses the rise in cell calcium induced by alpha-adrenergic stimuli.     

Histopathological and parasitological study of the gastrointestinal tract of dogs naturally infected with Leishmania infantum

Background

A nationwide survey on the microbial etiology of cases of subclinical mastitis in dairy cows was carried out on dairy farms in Sweden. The aim was to investigate the microbial panorama and the occurrence of antimicrobial resistance. Moreover, differences between newly infected cows and chronically infected cows were investigated.

Methods

In total, 583 quarter milk samples were collected from 583 dairy cows at 226 dairy farms from February 2008 to February 2009. The quarter milk samples were bacteriological investigated and scored using the California Mastitis Test. Staphylococci were tested for betalactamase production and presence of resistance was evaluated in all specific udder pathogens. Differences between newly infected cows and chronically infected cows were statistically investigated using logistic regression analysis.

Results

The most common isolates of 590 bacteriological diagnoses were Staphylococcus (S) aureus (19%) and coagulase-negative staphylococci (CNS; 16%) followed by Streptococcus (Str) dysgalactiae (9%), Str. uberis (8%), Escherichia (E.) coli (2.9%), and Streptococcus spp. (1.9%). Samples with no growth or contamination constituted 22% and 18% of the diagnoses, respectively. The distribution of the most commonly isolated bacteria considering only bacteriological positive samples were: S. aureus - 31%, CNS - 27%, Str. dysgalactiae - 15%, Str. uberis - 14%, E. coli - 4.8%, and Streptococcus spp. - 3.1%. There was an increased risk of finding S. aureus, Str. uberis or Str. dysgalactiae in milk samples from chronically infected cows compared to findings in milk samples from newly infected cows. Four percent of the S. aureus isolates and 35% of the CNS isolates were resistant to penicillin G. Overall, resistance to other antimicrobials than penicillin G was uncommon.

Conclusions

Staphylococcus aureus and CNS were the most frequently isolated pathogens and resistance to antimicrobials was rare.     

Orchidectomy versus buserelin in combination with cyproterone acetate, for 2 weeks or continuously, in the treatment of metastatic prostatic cancer. Preliminary results of EORTC-trial 30843

This prospective randomized phase III trial compares orchidectomy as standard androgen-deprivative therapy of advanced (metastatic) prostatic cancer with treatment using the LHRH agonist Buserelin^® administered as nasal spray 3 daily doses of 400 μg, and combined with cyproterone acetate (CPA) 3 daily doses of 50 mg orally for 2 weeks initially to prevent flare-up of the disease, or continuously as complete androgen blockade. The trial was closed to entry in September 1989 when 367 patients were recruited. Patients were stratified for performance status (WHO) and metastatic status prior to randomization. According to patient and disease characteristics spreading of patients over the 3 arms was without statistical significant differences. Ineligibility was 5 and 4% of the patients were only partly evaluable. In March 1990 a first, preliminary analysis was performed. At that time 207 patients were off-study for progression or death and median follow-up was 1 yr. As to time-to-progression and survival there were no significant differences between the 3 arms. The meaning of this in regard to results of other trials with complete androgen blockade is discussed.