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G Bertoni

Publications and source records attributed to G Bertoni.

At least 37 records · Page 2Linked to original sources
PubMed2000

In synergy with various cis-acting elements, plant insterstitial telomere motifs regulate gene expression in Arabidopsis root meristems.

The telo-box, an interstitial telomere motif, was shown to regulate gene expression in root meristems, in synergy with a cis-acting element involved in the activation of expression of plant eEF1A genes, encoding the translation elongation factor EF1A, and of several ribosomal protein genes. We demonstrate here that the telo-box is also required for transcription activation by two other cis elements present within the promoter of genes encoding the acidic ribosomal protein rp40 and the proliferating cell nuclear antigen respectively. The control of gene expression by telo-boxes during cell cycle progression in Arabidopsis root meristems is discussed. A parallel is drawn with the function of telomeric sequences in Saccharomyces cerevisiae.

Arabidopsis↗
PubMed2000

Effect of feeding pattern and behaviour on hormonal changes and milk composition.

There is no doubt that feeding and nutrient availability modify the metabolism through hormonal changes. It is otherwise interesting to better define the influence of the imposed or freely chosen meal distribution during the day; in fact the daily feed intake in a relatively short time, namely during the daylight, seems to induce a clear anabolic phase in afternoon-night (high insulin and low urea) and a catabolic one in the morning (low insulin and high urea); among the possible consequences, the lower fat content in the morning milking and the higher one in the afternoon, are of great importance. The factors that can influence these daily changes are many, namely the meal size, the day or night, the stage of lactation and perhaps a genetic effect. These results can be useful for a better interpretation of blood parameters and of the relationships between feeding and milk composition.

Animals↗
PubMed2000

Role of endotoxin and TNF-alpha in the pathogenesis of experimentally induced coliform mastitis in periparturient cows.

Twelve cows were experimentally infected in two quarters with 1 x 10(4) cfu Escherichia coli per quarter and six cows were infused with 500 microg endotoxin into two quarters. Six cows infected intramammarily with Esch. coli were treated intravenously with a bactericidal antibiotic 10 h after infection and subcutaneously 20 h later. Blood and milk samples were collected from all cows at regular time intervals. Milk production decreased more rapidly, but was less pronounced, after endotoxin infusion than (during Esch. coli mastitis. The milk production losses in the noninflamed quarters were negligible in endotoxin mastitis, but were substantial during Esch. coli mastitis, probably due to more pronounced systemic effects. Reticulorumen motility was inhibited only during Esch. coli mastitis. Changes in plasma haptoglobin were more pronounced during Esch. coli mastitis, although they occurred sooner during endotoxin mastitis. No changes in plasma activities of enzymes such as lactate dehydrogenase, glutamic-oxaloacetic transaminase and gamma-glutamyl transpeptidase were observed. Concentrations of tumour necrosis factor-alpha increased in both types of mastitis. Absorption of these cytokines into the circulation was highest during Esch. coli mastitis, especially in the untreated control group. We found only minor differences between the treated and untreated Esch. coli groups, but there were larger differences between the Esch. coli groups and the endotoxin group. These differences were probably due to differences in kinetics, composition and amounts of different cytokines released in the mammary gland and subsequently absorption into the circulation. Endotoxin is probably not directly responsible for the systemic changes during coliform mastitis.

Animals↗
PubMed2000

The detection of proviral DNA by semi-nested polymerase chain reaction and phylogenetic analysis of Czech Maedi-Visna isolates based on gag gene sequences.

A semi-nested polymerase chain reaction (snPCR) for detecting proviral DNA of ovine lentivirus (OvLV) in peripheral blood mononuclear cells was developed. Primers for snPCR were situated within the gag gene of the Maedi-Visna virus (MVV) genome. A comparison between the snPCR and serological tests (agar gel immunodiffusion test, immunoblot) were performed using 98 ovine blood samples. Thirty (30.6%) of the 98 sheep examined had antibodies specific for the MVV. PCR showed 21 of them to be positive and nine seropositive animals to be PCR negative. Six of the 68 serologically negative sheep were found to be PCR positive, probably due to delayed seroconversion. The PCR amplification products of these six sheep were sequenced and subjected to phylogenetic analysis. The resulting phylogenetic tree of partial gag gene sequences confirmed that the ovine lentivirus genotype in the Czech Republic is more closely related to the prototype MVV isolates than to the caprine arthritis encephalitis viruses.

Animals↗
PubMed1999

How to succeed as a virus: strategies for dealing with the immune system.

Viruses may be viewed as genetic information whose success depends on avoiding elimination from individual hosts, or, if this is not possible, in persisting in the population of their hosts. The immune system represents the crucial defense mechanism responsible for the elimination of viruses from individual hosts and for the establishment of immunity that prevents a recurring infection by the same virus. Herd immunity, i.e., immunity of the population against infection resulting from the immunity of a certain fraction of the individuals of the population, represents an important concept in the interaction of viruses with their hosts. Thus, if the number of susceptible hosts decreases below a critical threshold, viruses may risk extinction because they literally run out of substrate. This possibility is increased due to the viruses' low resistance to inactivation outside their hosts by physical influences, such as heat and ultraviolet radiation. Some viruses have adopted a strategy of dual host tropism, i.e., they may reside in reservoir hosts that permit them to survive for extended periods of times. Examples of such viruses are the large and taxonomically diverse group of arboviruses. Moreover, although not normally discussed under this aspect, influenza viruses can also be said to have adopted this strategy, in view of water fowl representing reservoir hosts from which complete viruses may directly cross over to mammals, as was the case with the equine Jilin (Guo et al., 1995) or, more recently, the H5 subtype of influenza virus in humans (Shortridge et al., 1998). In addition, influenza viruses of birds may be transmitted, albeit only partially, through genetic reassortment (Shu et al., 1996).

Animals↗
PubMed1999

Recruitment of RNA polymerase is a rate-limiting step for the activation of the sigma(54) promoter Pu of Pseudomonas putida.

The activity of the sigma(54)-promoter Pu of Pseudomonas putida was examined in vitro with a DNA template lacking upstream activating sequences, such that RNA polymerase can be activated by the enhancer-binding protein XylR only from solution. Although the transcription activation pathway in this system lacked the step of integration host factor (IHF)-mediated looping of the XylR.DNA complex toward the prebound RNA polymerase, IHF still stimulated promoter activity. The positive effect of IHF became evident not only with XylR from solution, but also with other sigma(54)-dependent activators such as NtrC and NifA. Furthermore, an equivalent outcome was shown for the nonspecific DNA-binding protein HU. This stimulation of transcription in the absence of the enhancer was traced to the recruitment of RNA polymerase (i.e. increased efficiency of formation of closed complexes) brought about by IHF or HU binding. Thus, under limiting concentrations of the polymerase, the factor-mediated binding of the enzyme to Pu seems to enter a kinetic checkpoint in the system that prevents the XylR-mediated formation of an open complex.

Bacterial Proteins↗
PubMed1999

Inducible nitric oxide synthase is expressed in joints of goats in the late stage of infection with caprine arthritis encephalitis virus.

We have studied the expression of the inducible form of nitric oxide synthase (iNOS) in joints of goats infected with the caprine arthritis encephalitis virus (CAEV). Nitric oxide generated by iNOS is thought to play an important role in the pathogenesis of various types of arthritis, especially rheumatoid arthritis (RA) in humans. Surprisingly, iNOS immunoreactivity was found only in joints of long-term infected goats with severe clinical arthritis, whereas-despite the presence of high numbers of inflammatory cells in the synovial tissue-no iNOS immunoreactivity was detected in mildly arthritic and in short-term experimentally infected goats. Most iNOS-positive cells expressed neither MHC class II nor CD68, which suggests that they were fibroblast-like synoviocytes. In situ hybridization studies showed that there was no correlation between iNOS immunoreactivity and detectable virus expression in the joint. In addition, infection of macrophages in vitro-the major host cells of CAEV in vivo-did not lead to increased iNOS mRNA expression. In response to stimulation, similar levels of iNOS expression were observed in infected and in uninfected macrophages. These findings suggest that the expression of iNOS is a feature of late-stage chronic arthritis and is not involved in the development of the inflammatory lesions. Both the lack of co-localization of iNOS protein and viral transcripts in the joint and the finding that CAEV does not stimulate the expression of iNOS in vitro further suggest that iNOS is not directly induced by the virus or the anti-viral immune response in the joint, that it may well, however, be involved in tissue remodelling or scar formation.

Animals↗
PubMed1999

The teeth of the horse: evolution and anatomo-morphological and radiographic study of their development in the foetus.

The aim of this work was to study the ontogenetic process in teeth from their early appearance in the ossifying matrix of the mandible and maxilla, in different foetuses of scalar ages. Radiographic examinations of the skull and mandible hemisections were performed and the latero-medial (LM) and dorsoventral (DV) projections for the skull and mandible were analysed. A high-definition film-screen combination was used for this study. The exposure values ranged from 35 kV/6 mAs to 58 kV/10 mAs, according to the size of the skulls and their degree of ossification. The first dental germ observed was the P3, at 138-140 days of pregnancy. At 146 days, P2 and P4 dental germs were visible. At 160-168 days, the dental germ of the first deciduous incisor tooth (I1) appeared; at 180-188 days of pregnancy the germ of the second (I2), and at 224 days the germ of the third (I3), were detectable. At 275 days the dental germ of the mandibular first molar tooth (M1) appeared, while the maxillary M1, which was not visible radiographically, was represented by a jelly-like amorphous body within its alveolar cavity.

Aging↗
PubMed1999

Dysplastic changes in gastric fundic gland polyps of patients with familial adenomatous polyposis.

BACKGROUND: Fundic gland polyps are the most common gastric lesion in patients with familial adenomatous polyposis and are traditionally considered a condition with no malignancy potential. However, some reports have recently questioned this view. AIMS: To prospectively evaluate their prevalence and the associated dysplastic/malignant changes in a series of affected patients. PATIENTS AND METHODS: Thirty-seven affected patients were carefully investigated by upper endoscopy over a three-year period. Multiple (at least 10) complete excisions of any representative polyp of the body-fundus were performed and a thorough pathological search for microscopic adenomatous/dysplastic changes carried out. RESULTS: Of 37 patients, 19 (51.3%) showed gastric fundic gland polyposis and 18 of them gave consent for polypectomies. Overall, 425 endoscopic polypectomies were performed, with a mean of 23.6 +/- 14.6 per patient. At pathology, all excised polyps of the body-fundus were found to be fundic glandular. Microscopic adenomatous changes within such polyps were identified in 8 (44.4%) patients. All the adenomatous foci revealed mild dysplasia with no case of severe atypia or carcinoma. Patients with microadenomas showed a significantly higher total number of gastric polyps compared with those without microadenomas (p < 0.03). No other differences between the two groups were observed. Two further patients presented microadenomas in apparently normal antral mucosa and one also showed a 6 mm antral adenoma with mild dysplasia. Finally, the search for Helicobacter pylori was always negative. CONCLUSIONS: Patients with familial adenomatous polyposis and gastric fundic gland polyps have a high prevalence of microscopic adenomatous foci within such lesions; nevertheless, these foci seem not to be associated with signs of severe atypia or carcinoma. Moreover, microadenomas are ubiquitous throughout the stomach, as well as in the rest of the gut, and their natural history is still undefined. Thus, their malignancy potential remains uncertain. More extensive follow-up is warranted to better investigate the long-term biological behaviour of these lesions but, at present, our data do not support the need for a change in the usual intervals of upper endoscopy surveillance in familial polyposis patients with or without gastric fundic glands polyps.

Adenomatous Polyposis Coli↗
PubMed1999

Clinical features and genotype-phenotype correlations in 41 Italian families with adenomatosis coli.

BACKGROUND: Familial Adenomatous Polyposis in an autosomal dominant disease in which the large bowel is carpeted by polyps of various dimensions appearing during the second or third decade of life. Several extracolonic manifestations complete the clinical spectrum of Familial Adenomatous Polyposis. If untreated, the disease leads invariably to colorectal cancer. The gene responsible for the disease, adenomatous Polyposis Coli, has been localized at chromosome 5q21. AIMS: To describe the clinical features of 156 Familial Adenomatous Polyposis patients (from 41 families) and to analyze possible correlations between genotype and phenotype. PATIENTS AND METHODS: Familial Adenomatous Polyposis was defined as the presence of 100 or more polyps in the large bowel. In 17 families (41%), the proband was the only affected individual (single cases). Adenomatous Polyposis Coli gene mutations were studied on DNA extracted from peripheral white blood cells and evaluated by polymerase chain reaction single strand conformation polymorphism, followed by direct sequencing of samples showing abnormal banding at single strand conformation polymorphism. RESULTS: The large majority of Familial Adenomatous Polyposis patients underwent surgery; colectomy with ileorectal anastomosis was the most frequent approach, however, cancer of the rectal stump developed in 11.6% of patients submitted to colectomy and ileorectal anastomosis. Adenomas were rare in the stomach (8.8%), but their frequency increased in the duodenum (33.8%) and jejunum (55.0%, chi 2 for trend 23.7, p < 0.001). Desmoid tumours were diagnosed in 17 patients (10.9% of the total) and in 6 families. Mutations of the Adenomatous Polyposis Coli gene were studied in 20 out of 25 families (80%) and on a total of 75 individuals. The most frequent alterations were 1 to 5 bp deletions leading to stop codons and truncated proteins. Desmoid tumours, presence of duodenal or jejunal adenomas were associated with an ample range of mutations, from codon 215 to codon 1464. In contrast, particularly severe polyposis (mean age at appearance of polyps 11-16 years, and of cancer development 27-32 years) was associated with a "hotspot" mutation site at codons 1303-1309. CONCLUSIONS: In patients with Familial Adenomatous Polyposis, subtotal colectomy with ileorectal anastomosis is still the treatment of choice. Adenomatous lesions seem to show a "gradient" distribution from the stomach to the large bowel. Desmoid tumours are relatively common, though their incidence is limited to some of the families. Constitutional mutations can be detected in 80% of the investigated families. Genotype-phenotype correlations showed a hot-spot at codons 1303-1309, frequently associated with severe polyposis.

Adenomatous Polyposis Coli↗
PubMed1998

Active recruitment of sigma54-RNA polymerase to the Pu promoter of Pseudomonas putida: role of IHF and alphaCTD.

The sequence elements determining the binding of the sigma54-containing RNA polymerase (sigma54-RNAP) to the Pu promoter of Pseudomonas putida have been examined. Contrary to previous results in related systems, we show that the integration host factor (IHF) binding stimulates the recruitment of the enzyme to the -12/-24 sequence motifs. Such a recruitment, which is fully independent of the activator of the system, XylR, requires the interaction of the C-terminal domain of the alpha subunit of RNAP with specific DNA sequences upstream of the IHF site which are reminiscent of the UP elements in sigma70 promoters. Our data show that this interaction is mainly brought about by the distinct geometry of the promoter region caused by IHF binding and the ensuing DNA bending. These results support the view that binding of sigma54-RNAP to a promoter is a step that can be subjected to regulation by factors (e.g. IHF) other than the sole intrinsic affinity of sigma54-RNAP for the -12/-24 site.

Bacterial Proteins↗
PubMed1998

Differences between B cell and macrophage transformation by the bovine parasite, Theileria annulata: a clonal approach.

Theileria annulata, a tick-transmitted protozoan parasite, infects and transforms cells of the hemopoietic system, particularly those of the B cell and monocyte/macrophage lineages. Here, the effect of infection/transformation on the resulting phenotype was studied using a clonal approach. Three phenotypes of transformed cell lines could be discerned. The first is characterized by surface expression of IgM, CD21, and the B cell epitopes, B-B2 and B-B8, Ig heavy chain gene rearrangement, and mRNA expression. Such lines were obtained from fresh and cultured PBMC and at increased frequency from purified B cells, but never from fetal bone marrow cells. The second phenotype can be distinguished from the first by the absence of Ig heavy chain expression and reduced surface expression of B cell markers (CD21, B-B2, B-B8). Clones with this phenotype were obtained from transformed fetal bone marrow cells only. The third phenotype showed an absence of all of the above B cell markers, including surface IgM, and a lack of Ig heavy chain gene rearrangement. The latter clones could be maintained for several weeks after elimination of T. annulata by BW720c treatment, and they reacquired a macrophage-like phenotype. This implies that parasite-induced dedifferentiation is restricted to monocyte/macrophage, and that B cell markers are indicative of cell lineage progeny. Demonstration of surface IgM on PBMC-derived B cell clones suggests that infection of B cells with T. annulata may be an epigenetic method to immortalize ruminant B cells of a defined Ag specificity.

Animals↗
PubMed1998

Caprine T-cell receptor variable beta-chain (TCRV beta) repertoire analysis and potential applications in cowdriosis immune response studies.

Anchor polymerase chain reaction has been applied to the study of caprine TCR V beta-chain repertoire at the mRNA level in peripheral blood of a Saanen goat. Single stranded, g-tailed cDNA synthesized from total RNA was PCR-amplified using a sheep V beta constant region primer (3') and a poly(dC) anchor primer (5') at the variable region end of the TCR V beta-chain. The obtained amplicon was subsequently cloned into Bluescript plasmid vector. A total of 72 recombinant clones whereof 61 contained an insert of appropriate size were harvested. Up to now, the full length sequences of a total of 55 clones have been obtained. Nine clones were rearranged but not functional due to stop codons. Forty-five sequences were functionally rearranged and further analyzed. They were classified into 15 different V beta families on the basis of V-region sequence homology with their human counterpart. V beta families corresponding to the 9 published bovine families were represented in our library. This complexity enables us to develop V beta family-specific primers in order to study the TCR V beta repertoire of other goat breeds of interest, i.e., the Creole goat. There the TCR V beta repertoire analysis and kinetic study of the cowdriosis model will provide insight into the type of the immune response and the status of protection during the immunization process and challenge.

Animals↗
PubMed1998

Treatment and prognosis in a series of primary extranodal lymphomas of the ocular adnexa.

BACKGROUND: The aim of this study was to assess clinicopathological characteristics and outcome in a series of primary ocular adnexal lymphomas (POALs). PATIENTS AND METHODS: Nineteen patients with localised (stage IE) POAL were followed for a median of 96 months (24-156). The diagnosis was based on surgical biopsies followed by immunohistochemistry in 16 cases or fine-needle aspiration followed by immunocytophenotypic analysis in three cases. Twelve patients were treated with local radiotherapy (RT), five with chemotherapy (CT), and two refused further therapy after apparently radical tumour removal achieved by the diagnostic excisional biopsy. RESULTS: The histological and immunological pattern was consistent with a diagnosis of MALT-type lymphoma (11 cases), follicular center non-Hodgkin's lymphoma (three cases). a large-cell variant of Burkitt's lymphoma (one case), and large-cell transformed MALT lymphoma (one case). Low-grade lymphoma was diagnosed in the three cases which underwent fine-needle aspiration biopsy. All of the patients achieved and maintained complete remission except for those treated with surgical excision alone (two MALT conjunctival lymphoma cases): one of these relapsed locally, the other experienced the systemic spread of a transformed diffuse large-cell lymphoma and died 72 months after diagnosis. The side effects consisted of two cases of RT-related cataract after 52 and 72 months. CONCLUSIONS: Regardless of histology, prognosis was excellent when surgery plus RT was adopted, and CT seems to be a valid alternative to RT. Surgery alone may be sub-optimal.

Adult↗
PubMed1998

Immunohistology of the early course of lentivirus-induced arthritis.

Caprine arthritis encephalitis (CAE) is a lentiviral infection of goats characterized by mononuclear cell infiltration of various tissues, most prominently the joints, mammary glands and, in young animals, the brain. We have investigated the early stages of arthritis induced by intracarpal and intravenous infection with molecularly cloned CAE virus. Analysis of the synovial membranes by immunohistological methods showed that the proportion of CD8+ T cells peaked around day 12 post-infection. CD4+ T cells increased to a lesser degree. The relative proportion of B cells rose steadily post-infection. At 33 days post-infection, plasma cells accounted for over one third of all inflammatory cells in the inflamed synovium. Histopathologically, the arthritic lesions in the synovial membranes closely resembled those in membranes of animals with a 2-year history of chronic arthritis. Our observations indicate that this type of short-term experimental infection is particularly suitable for studying the pathogenesis of goat lentiviral infection. In addition, our observations support the view that a predominantly humoral (type 2) immune response may contribute to the pathogenesis of CAE.

Animals↗
PubMed1998

Activation of the toluene-responsive regulator XylR causes a transcriptional switch between sigma54 and sigma70 promoters at the divergent Pr/Ps region of the TOL plasmid.

The mechanism by which XylR, the toluene-responsive activator of the sigma54-dependent Pu and Ps promoters of the Pseudomonas TOL plasmid pWW0, downregulates its own sigma70 promoter Prhas been examined. An in vitro transcription system was developed in order to reproduce the repression of Probserved in cells of P. putida (pWW0) both in the presence and in the absence of the XylR inducer, benzyl alcohol. DNA templates bearing the two sigma70-RNA polymerase (RNAP) binding sites of Pr, which overlap the upstream activating sequences (UAS) for XylR in the divergent sigma54 promoter Ps, were transcribed in the presence of a constitutively active XylR variant deleted of its N-terminal domain (XylRdeltaA). The addition of ATP, known to trigger multimerization of the regulator at the UAS, enhanced the repression of Pr by XylR. Furthermore, we observed activation of the divergent sigma54 promoter Ps during Pr downregulation by XylRdeltaA. These results support the notion that activation of XylR by aromatic inducers in vivo triggers a transcriptional switch between Pr and Ps. Such a switch is apparently caused by the ATP-dependent multimerization and strong DNA binding of the protein required for activation of the sigma54 promoter. This device could reset the level of XylR expression during activation of the sigma54 Pu and Ps promoters of the TOL plasmid.

Adenosine Triphosphate↗
PubMed1998

Anatomo-radiographic study on the osteogenesis of carpal and tarsal bones in horse fetus.

The aim of this study is to point out the time of appearance of the carpal and tarsal bones in the fetal horse, considering an estimated fetal age, to follow their morphological development through to birth, and to characterize possible abnormal shape and/or delay of their ossification. The right carpal and tarsal region of 140 equine fetuses of both sexes (71 males, 69 females) and different ages (from 70 to 340 days of gestation) were examined radiographically in order to identify the sites of ossification from their earliest appearance. The times of appearance of the sites of ossification of the carpal bones are chronologically stated for each bone.

Animals↗