scholarly journals An ever-green mind and a heart for the colors of fall

2021 ◽  
Author(s):  
Sylvain Aubry ◽  
Bastien Christ ◽  
Bernhard Kräutler ◽  
Enrico Martinoia ◽  
Howard Thomas ◽  
...  
Keyword(s):  
Degradation Products ◽  
Degradation Pathway ◽  
Chlorophyll Degradation ◽  
Biochemical Pathway ◽  
Plant Senescence ◽  
Molecular Approaches ◽  
Complex Regulation

Abstract With finest biochemical and molecular approaches, convincing explorative strategies and long-term vision, Stefan Hörtensteiner succeeded in elucidating the biochemical pathway responsible for chlorophyll degradation. After having contributed to the identification of key chlorophyll degradation products in the course of the last twenty-five years, he gradually identified and characterized most of the crucial players in the PAO/phyllobilin degradation pathway of chlorophyll. One of the brightest plant biochemists of his generation, his work opened doors to a better understanding of plant senescence, tetrapyrrole homeostasis and their complex regulation. He sadly passed away on 5 December 2020, aged 57.

scholarly journals Contextualizing Autophagy during Gametogenesis and Preimplantation Embryonic Development

2021 ◽  
Vol 22 (12) ◽  
pp. 6313
Author(s):  
Marcelo T. Moura ◽  
Laís B. Latorraca ◽  
Fabíola F. Paula-Lopes
Keyword(s):  
Embryonic Development ◽  
Germ Cells ◽  
Physiological Role ◽  
Degradation Pathway ◽  
Environmental Stressors ◽  
Preimplantation Embryos ◽  
Environmental Cues ◽  
Term Survival ◽  
Assisted Reproduction Technologies

Mammals face environmental stressors throughout their lifespan, which may jeopardize cellular homeostasis. Hence, these organisms have acquired mechanisms to cope with stressors by sensing, repairing the damage, and reallocating resources to increase the odds of long-term survival. Autophagy is a pro-survival lysosome-mediated cytoplasm degradation pathway for organelle and macromolecule recycling. Furthermore, autophagy efflux increases, and this pathway becomes idiosyncratic depending upon developmental and environmental contexts. Mammalian germ cells and preimplantation embryos are attractive models for dissecting autophagy due to their metastable phenotypes during differentiation and exposure to varying environmental cues. The aim of this review is to explore autophagy during mammalian gametogenesis, fertilization and preimplantation embryonic development by contemplating its physiological role during development, under key stressors, and within the scope of assisted reproduction technologies.

scholarly journals Molecular Epidemiology of Tuberculosis: Current Insights

2006 ◽  
Vol 19 (4) ◽  
pp. 658-685 ◽  
Author(s):  
Barun Mathema ◽  
Natalia E. Kurepina ◽  
Pablo J. Bifani ◽  
Barry N. Kreiswirth
Keyword(s):  
Vaccine Development ◽  
Epidemiologic Studies ◽  
Molecular Techniques ◽  
Tb Control ◽  
Molecular Approaches ◽  
Accuracy And Precision ◽  
Outbreak Investigations ◽  
Short And Long Term ◽  
Exogenous Reinfection

SUMMARY Molecular epidemiologic studies of tuberculosis (TB) have focused largely on utilizing molecular techniques to address short- and long-term epidemiologic questions, such as in outbreak investigations and in assessing the global dissemination of strains, respectively. This is done primarily by examining the extent of genetic diversity of clinical strains of Mycobacterium tuberculosis. When molecular methods are used in conjunction with classical epidemiology, their utility for TB control has been realized. For instance, molecular epidemiologic studies have added much-needed accuracy and precision in describing transmission dynamics, and they have facilitated investigation of previously unresolved issues, such as estimates of recent-versus-reactive disease and the extent of exogenous reinfection. In addition, there is mounting evidence to suggest that specific strains of M. tuberculosis belonging to discrete phylogenetic clusters (lineages) may differ in virulence, pathogenesis, and epidemiologic characteristics, all of which may significantly impact TB control and vaccine development strategies. Here, we review the current methods, concepts, and applications of molecular approaches used to better understand the epidemiology of TB.

Stability and epimerisation behaviour of ergot alkaloids in various solvents

2008 ◽  
Vol 1 (1) ◽  
pp. 67-78 ◽  
Author(s):  
M. Hafner ◽  
M. Sulyok ◽  
R. Schuhmacher ◽  
C. Crews ◽  
R. Krska
Keyword(s):  
Degradation Products ◽  
Ergot Alkaloids ◽  
Carbonate Buffer ◽  
Long Term Storage ◽  
No Formation ◽  
Temperature Levels ◽  
The Stability ◽  
Extraction Mixture ◽  
Term Storage

In this paper the stability and degree of epimerisation of six major ergot alkaloids at three different temperature levels (-20 °C, +4 °C and +20 °C) over periods of 18 hours and six weeks is reported for the first time. The behaviour of ergometrine, ergocornine, ergocristine, α-ergocryptine, ergosine and ergotamine was thoroughly studied in seven solvents which are employed for the preparation of calibrants and extraction mixtures, respectively. Moreover, the stability of the ergot alkaloids was tested in different cereal extracts (rye, wheat, barley, oats) for 1, 2 and 6 days. Of the toxins tested, the ergopeptide-type toxins ergosine, ergotamine, ergocornine, α-ergocryptine and ergocristine showed similar behaviour patterns. The simple lysergic acid derivative ergometrine was more stable and showed hardly any epimerisation to ergometrinine, with the sum of both epimers remaining constant in all seven solvents. The ergopeptides tested show variable epimerisation tendencies, and were also less stable during six weeks at 20 °C. Ergosine showed the highest degree of epimerisation (43% after 6 weeks at 20 °C). In general, the order of epimerisation promotion was methanol/dichloromethane > acetonitrile/buffer > extraction mix > stabilising solution > acetonitrile >> chloroform. Long-term storage at room temperature can only be carried out in chloroform, which showed no epimerisation for all toxins even at 20 °C and also kept the sum of R and S forms constant, which indicates no formation of aci-epimers or other degradation products. Long-term storage of ergot alkaloids in acetonitrile, the most convenient solvent with respect to HPLC analysis, should be carried out at temperatures of -20 °C or below. The constant epimer ratio of all ergot alkaloids in the extraction mixture acetonitrile/ammonium carbonate buffer (200 mg/l; 92:8, v/v) during an HPLC run (18 hours) demonstrates the stability of the toxins in this extraction mixture.

scholarly journals A49 Emerging rodent-borne viral pathogens in Italy: Overview of seroprevalence and genomic investigations

2019 ◽  
Vol 5 (Supplement_1) ◽  
Author(s):  
N Alfano ◽  
V Tagliapietra ◽  
D Arnoldi ◽  
F Rosso ◽  
C Rossi ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Rna Viruses ◽  
Case Fatality ◽  
Lymphocytic Choriomeningitis ◽  
Immunofluorescence Assay ◽  
Sudden Increase ◽  
Viral Pathogens ◽  
Molecular Approaches ◽  
Northeastern Italy

Abstract Rodents play a key role as reservoirs of many zoonotic pathogens which represent an emerging public health threat worldwide. Among these, Dobrava-Belgrade virus (DOBV) is the most pathogenic hantavirus in Europe with a case-fatality rate of up to 12 per cent, while Lymphocytic choriomeningitis virus (LCMV) has a mortality rate below 1 per cent. Both viruses are predominantly transmitted to humans through the inhalation of infected particles in aerosolized urine, feces, or saliva that are shed in the environment by chronically infected hosts, such as the yellow-necked mouse Apodemus flavicollis. Although no human cases of DOBV or LCMV have been reported in the Province of Trento (northeastern Italy) thus far, in order to evaluate the human hazard for these viruses, the prevalence of antibodies to DOBV and LCMV has been monitored using a specific immunofluorescence assay test in a wild population of A. flavicollis since 2000. These investigations have shown that the two RNA viruses circulate silently in this species in the study area. In particular, a sudden increase (up to 12.5%) in DOBV seroprevalence was observed in this rodent species between 2010 and 2012. Several efforts have been undertaken to isolate these viruses and characterize their genomes, but it has not yet been possible to detect viral RNA from seropositive mice using traditional methods such as RT-PCR. Since RNA viruses are very diverse and often difficult to isolate, innovative molecular methods based on viral targeted enrichment and high-throughput sequencing have been applied. We intend to report on this long-term seroprevalence study and provide an overview of the molecular approaches adopted in the attempt to confirm the presence of these viruses, and identify which variants are circulating in the region, as well as their pathogenicity.

Biological Significance of Reducing Glucose Degradation Products in Peritoneal Dialysis Fluids

2000 ◽  
Vol 20 (5_suppl) ◽  
pp. 23-27 ◽  
Author(s):  
Anders Wieslander ◽  
Torbjörn Linden ◽  
Barbara Musi ◽  
Ola Carlsson ◽  
Reinhold Deppisch
Keyword(s):  
Peritoneal Dialysis ◽  
Side Effects ◽  
Host Defense ◽  
Degradation Products ◽  
Biological Significance ◽  
Peritoneal Membrane ◽  
Negative Side ◽  
Glucose Degradation Products ◽  
Negative Side Effects

Carbohydrates are not stable when exposed to energy; they degrade into new molecules. In peritoneal dialysis (PD) fluids, degradation of glucose occurs during the heat sterilization procedure. The biological consequences of this degradation are side effects such as impaired proliferation and impaired host defense mechanisms, demonstrated in vitro for a great variety of cells. Several highly toxic compounds—such as formaldehyde and 3-deoxyglucosone—have been identified in PD fluids. Carbonyl compounds, apart from being cytotoxic, are also well-known promoters of irreversible advanced glycation end-products (AGEs), which might participate in the long-term remodeling of the peritoneal membrane. Various approaches can be used to reduce the formation of glucose degradation products (GDPs) during heat sterilization. Some examples are shortening the sterilization time, lowering the pH, removing catalyzing substances, and increasing glucose concentration. The latter three factors are employed in the multi-compartment bag with a separate chamber containing pure glucose at high concentration and low pH. Gambrosol trio, a PD fluid produced in this way, shows reduced cytotoxicity, normalized host defense reactions, less AGE formation, and reduced concentrations of formaldehyde and 3-deoxyglucosone. Moreover, in the clinical situation, the fluid turns out to be more biocompatible for the patient, causing less mesothelial cell damage, which in the long term could lead to a more intact peritoneal membrane. Conclusion Glucose degradation products in heat-sterilized fluids for peritoneal dialysis are cytotoxic, promote AGE formation, and cause negative side effects for the patient. Using improved and well-controlled manufacturing processes, it is possible to produce sterile PD fluids with glucose as the osmotic agent but without the negative side effects related to GDPs.

Analysis on the Stability of Total Phenolic Acids and Salvianolic Acid B from Salvia miltiorrhiza by HPLC and HPLC-MSn

2008 ◽  
Vol 3 (5) ◽  
pp. 1934578X0800300 ◽  
Author(s):  
Man Xu ◽  
Jian Han ◽  
Hui-feng Li ◽  
Li Fan ◽  
Ai-hua Liu ◽  
...  
Keyword(s):  
Phenolic Acids ◽  
Degradation Products ◽  
Biological Fluids ◽  
Salvia Miltiorrhiza ◽  
Degradation Pathway ◽  
Salvianolic Acid B ◽  
Total Phenolic ◽  
Salvianolic Acid ◽  
The Stability

The stability of salvianolic acid B and total phenolic acids from Salvia miltiorrhiza in water solutions at different temperatures, in buffered aqueous solutions at different pHs and in biological fluids, including simulated gastric and intestinal fluids, were investigated in vitro. The results showed that the degradation of salvianolic acid B was pH- and temperature-dependent. Furthermore, structures of the degradation products of salvianolic acid B and total phenolic acids were elucidated by liquid chromatography-electrospray ion trap mass spectrometry and analysis of the degraded solutions revealed seventeen degradation products. The possible degradation pathway of salvianolic acid B is proposed.

A Short Review of Experimental Peritoneal Sclerosis: From Mice to Men

2005 ◽  
Vol 28 (2) ◽  
pp. 97-104 ◽  
Author(s):  
L. Gotloib ◽  
V. Wajsbrot ◽  
A. Shostak
Keyword(s):  
Degradation Products ◽  
Pure Water ◽  
Fibrous Tissue ◽  
Short Review ◽  
Glucose Absorption ◽  
Low Ph ◽  
Thick Sheet ◽  
Other Substances

Peritoneal sclerosis has been induced in rodents in vivo by exposing the membrane to a variety of experimental interventions: asbestos, 0.1% chlorexidine, iron dextran, glucose degradation products, AGE deposits derived from uremia per se, sodium hypochlorite, lypopolysaccharide, low pH, pure water, silica or zymosan. With a few exceptions (pure water, chlorhexidine and low pH), the other substances mentioned operate setting out different degrees of oxidative stress. This short review describes several experimental interventions in rodents, aimed at acute exfoliation or long-term, sustained injury of the mesothelial monolayer performed by means of intraperitoneal injections of different oxidant agents. Acute exfoliation induced by deoxycholate resulted in a depopulated monolayer coincident with immediate alteration of the peritoneal permeability, evidenced by increased urea D/P ratio, higher glucose absorption rate, elevated albumin losses in the effluent and significant reduction of the ultrafiltration rate. In the long term (30 days), these manifestations of membrane failure persisted and coincided with substantial peritoneal sclerosis. Peritoneal sclerosis was also induced by IP injections of 0.125% trypsin and 6.6 mM/L solution of formaldehyde. Using the doughnut rat model of mesothelial regeneration, exposure to 4.25% glucose or 7.5% icodextrin solutions severely hampered repopulation of the monolayer, which was replaced by a thick sheet of fibrous tissue. It is concluded that peritoneal sclerosis derives mostly from sustained oxidative injury to the peritoneal membrane. Loss of the mesothelial monolayer is the first step in the chain of events leading to this complication.

Sign in / Sign up

Export Citation Format

Share Document