Rhizobium Lipooligosaccharides Rescue a Carrot Somatic Embryo Mutant.

At a nonpermissive temperature, somatic embryos of the temperature-sensitive (ts) carrot cell mutant ts11 only proceed beyond the globular embryo stage in the presence of medium conditioned by wild-type embryos. The causative component in the conditioned medium has previously been identified as a 32-kD acidic endochitinase. In search of a function for this enzyme in plant embryogenesis, several compounds that contain oligomers of N-acetylglucosamine were tested for their ability to promote ts11 embryo formation. Of these compounds, only the Rhizobium lipooligosaccharides or nodulation (Nod) factors were found to be effective in rescuing the formation of ts11 embryos. These results suggest that N-acetylglucosamine-containing lipooligosaccharides from bacterial origin can mimic the effect of the carrot endochitinase. This endochitinase may therefore be involved in the generation of plant analogs of the Rhizobium Nod factors.

Risk factors associated with cytomegalovirus infection in orthotopic liver transplant patients.

UNLABELLED: Our objective was to investigate the potential risk factors associated with cytomegalovirus (CMV) infection. PATIENTS AND METHODS: From January 1999 to December 2001, 163 liver transplantations were performed in 154 patients. The study inclusion criteria were absence of retransplantation and survival of more than 6 months. One hundred fifteen patients met the inclusion criteria. We determined variables such as age, gender, and number of hemecomponents as well as serum IgG CMV status of donors and recipients. We recorded the immunosuppression used by each patient. CMV infection was detected by positive antigenemia. RESULTS: Recipient mean age was 50 years. The etiology of cirrhosis was viral (n = 57; 49.6%), alcoholic (n = 20; 17.4%), virus and alcohol (n = 15; 13.0%), cryptogenic (n = 14; 12.2%), or other causes (n = 9; 7.8%). CMV infection was positive in 75 patients (65.8%). There was no relation between infection and age, gender, or CMV IgG donor recipient status, or the number of hemecomponent units. The risk was 3.8-fold higher for patients receiving a three-drug compared with a two-drug regimen. When cyclosporine was used instead of tacrolimus, the risk of CMV infection was 4.3-fold higher. Logistic regression analysis revealed cyclosporine (OD=5.8) and a three-drug regimen (OD=6.7) to have stronger associations with CMV infection. CONCLUSION: The use of cyclosporine (OD=5.8) and a three-drug regimen (OD=6.7) are risk factors for CMV infection.

Impact of cytomegalovirus infection on long-term survival after orthotopic liver transplantation.

UNLABELLED: Cytomegalovirus (CMV) is one of the most common and serious opportunistic infections in solid organ transplant patients. In different series the incidence of CMV infection ranges from 25% to 85%. An indirect effect of infection includes reduced long-term patient and allograft survival. Our objective was to determine the relationship between CMV infection and patient survival after orthotopic liver transplantation. PATIENTS AND METHODS: From January 1999 to December 2001, 163 orthotopic liver transplantations were performed in 154 patients. The inclusion criteria for this analysis were the absence of retransplantation and survival of more than 6 months. One hundred fifteen patients met the inclusion criteria. CMV infection was detected by positive antigenemia. RESULTS: CMV infection occurred in 65.8% of patients after orthotopic liver transplantation. Their 5-year survival was 85%, with no difference observed between patients with or without infection (P = .8). CONCLUSION: CMV infection did not interfere with patient survival after orthotopic liver transplantation.

Risk factors associated with cytomegalovirus-positive antigenemia in orthotopic liver transplant patients.

The aim of the study was to investigate risk factors associated with cytomegalovirus (CMV)-positive antigenemia in orthotopic liver transplant (OLT) patients. Sixty-nine patients undergoing OLT during 2001 were retrospectively evaluated for CMV antigenemia during a follow-up of 6 months after transplantation for demographic variables, pretransplant donor and recipient CMV serologic status, etiology of liver disease, number of blood transfusions, and type of immunosuppression. Among the 69 patients who underwent 71 OLT in this period, 43 met study criteria. Mean age was 49.7 +/- 10.8 years and 60.5% were men. End-stage liver disease was the indication for liver transplant, except in one case. The most prevalent etiology of liver disease was hepatitis C and/or alcohol in 66% of the cases. CMV-positive status was recorded in 74% of donors and 95% of recipients. None of the CMV-negative recipients received a positive donor allograft. CMV-positive antigenemia was 84% with 12% having two episodes of infection. There was no correlation between CMV infection and age, gender, etiology of liver disease, or number of blood transfusions. However, all patients using cyclosporine had CMV-positive antigenemia compared with 61% using tacrolimus (P <.032). In this study, the incidence of CMV infection after OLT in adult patients was slightly higher than reported in literature. No risk factor was associated with CMV antigenemia; however, this study suggests a higher probability of CMV infection among patients treated with cyclosporine.

Analysis of the heat-shock protein pattern during somatic embryogenesis of carrot.

The pattern of proteins synthesized by carrot cells after heat-shock was analyzed by SDS-polyacrylamide gel electrophoresis. A study was made of the time of appearance and disappearance of the heat-shock bands and a comparison was made of the heat-shock proteins present in cell extracts obtained from cell suspensions, callus, protoplasts and the different stages of somatic embryogenesis.From this comparison a number of differences and hence of stage-specific markers could be seen. This type of analysis was also carried out in the presence of α-amanitin in order to get information on the type of control of heat-shock protein synthesis. It turned out that in all stages after the initial globular stage, α-amanitin does not alter the heat-shock protein pattern suggesting pre-existence of the relative mRNA's.

Genetic effects of griseofulvin on plant cell cultures.

Griseofulvin induces metaphase arrest and polyploidization in plant cells in culture; after which a process of chromosome segregation follows. During this process spontaneous or induced recessive mutations become expressed through the formation of homozygotes or monosomics. This finding can be of use whenever the isolation of recessive mutations is needed and haploid culture is difficult.

alpha-Amanitin resistance is developmentally regulated in carrot.

Carrot cells are capable of inactivating alpha-amanitin only in embryogenic conditions (regenerating cells and embryoids). Instead, the mutant line a3 is capable of inactivating the drug also in nonembryogenic conditions (vegetative growth). The mutation is dominant in somatic hybrids and is pleiotropic, allowing expression during vegetative growth of other embryonal functions. The inactivation of alpha-amanitin is due to the oxidative activity of tyrosinase.

[Acute sepsis caused by "Gaffkya tetragena" in adult with hypogammaglobulinemia (author's transl)]. / Sepsi acuta da "Gaffkya tetragena" in adulto con ipogammaglobulinemia

A case of acute sepsis caused by Gaffkya tetragena in an adult with acquired hypogammaglobulinemia has been described. The Authors pointout the importance that particular conditions of disreactivity and/or of immunodeficiency can play in the acquistion of pathogenicity by Gaffkya tetragena. In the case under discussion a high deficit of IgG and IgA was demonstrable, which had previously caused a long series of infective bacterial diseases.

A protocol for obtaining embryogenic cell lines from Arabidopsis.

Embryogenic cell lines with lasting embryogenic potential can be obtained from somatic embryos induced directly from zygotic embryos of Arabidopsis thaliana, ecotype Columbia. The response to a critical concentration of auxin, which seems to be the all-important factor in the generation of embryogenic cell lines, is exhibited by somatic embryos but not by zygotic ones. The basis for this differential response remains obscure and will be discussed in relation to other systems.

KDC1, a novel carrot root hair K+ channel. Cloning, characterization, and expression in mammalian cells.

Potassium is an essential nutrient which plays an important role in many aspects of plant growth and development. Plants have developed a number of highly specific mechanisms to take up potassium from the soil; these include the expression of K(+) transporters and potassium channels in root cells. Despite the fact that root epidermal and hair cells are in direct contact with the soil, the role of these tissues in K(+) uptake is not well understood. Here we report the molecular cloning and functional characterization of a novel potassium channel KDC1 which forms part of a new subfamily of plant K(in) channels. Kdc1 was isolated from carrot root RNA and in situ hybridization experiments show Kdc1 to be highly expressed in root hair cells. Expressing the KDC1 protein in Chinese hamster ovary cells identified it as a voltage and pH-dependent inwardly rectifying potassium channel. An electrophysiological analysis of carrot root hair protoplasts confirmed the biophysical properties of the Kdc1 gene product (KDC1) in the heterologous expression system. KDC1 thus represents a major K(+) uptake channel in carrot root hair cells.