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1.
Ophthalmologie ; 120(2): 178-183, 2023 Feb.
Article in German | MEDLINE | ID: mdl-35925354

ABSTRACT

BACKGROUND: Bottlenecks in drug supply in the field of ophthalmological are continuously increasing in Germany. So far, these have hardly been communicated and discussed. We see the transparent presentation of the problem as a first step in compiling concepts to counteract this development. AIM OF THE WORK: Presentation of the supply shortages in ophthalmological drugs. MATERIAL AND METHODS: A listing and discussion of the shortages in drug supply to the best of our knowledge are presented. RESULTS: We distinguish between the problems in (1) supply shortages, (2) discontinuation of production, (3) lack of availability in Germany and (4) manufacture of drugs in specialized pharmacies often lacking approval for the ophthalmological indications. DISCUSSION: The reasons for drug supply shortages in ophthalmology are complex and therefore no easy solutions can be expected; however, industrial and regulatory authorities at the national and European levels are called upon to analyze the underlying problems and to find appropriate solutions.


Subject(s)
Ophthalmology , Universities , Germany , Industry
2.
Hautarzt ; 69(9): 737-750, 2018 Sep.
Article in German | MEDLINE | ID: mdl-29589043

ABSTRACT

Two African girls who moved to Germany only 4 weeks ago presented to the dermatological office with itchy and scaling skin lesions of the scalp and the thighs. The entire scalp of both girls was affected by a white, dry dandruff and a squamous crust. Dry centrifugal spreading erythematosquamous lesions were found on the thighs. The surface of the left thumbnail of the younger girl was whitish. The Blancophor® preparations which were performed under the suspicion of a tinea capitis et corporis and onychomycosis from skin scrapings of the scalp and the thighs, and from the thumbnail of the younger child were positive. Cultivation of three samples from the affected body sites-hair, skin and nail-revealed Trichophyton (T.) soudanense. For confirmation of the species identification, the isolates were subject of sequencing of ITS region of the rDNA and also of the translation elongation factor 1 α (TEF 1 α) gene. The phylogenetic analysis of the strains-the dendrogram of fungal strains-demonstrated the genetic differences between T. soudanense and T. rubrum. In contrast, sequencing of the TEF 1 α gene did not allow any discrimination between T. soudanense and T. rubrum. Both girls were treated orally with fluconazole. For topical treatment of both girls, ciclopirox olamine solution and terbinafine cream were administered, each once daily. After 8 weeks oral fluconazole therapy the dermatomycoses of skin, scalp, and thumbnail of both children were completely healed. Currently, in Germany and Europe, in immigrants from West African countries (e. g., from Angola) dermatophytoses due to T. soudanense have to be expected. Cultural identification of the pathogen is relatively simple. However, only molecular methods allow the exact discrimination of T. violaceum and T. rubrum.


Subject(s)
Antifungal Agents , Dermatomycoses , Fluconazole , Onychomycosis , Tinea Capitis , Antifungal Agents/therapeutic use , Child , Dermatomycoses/drug therapy , Europe , Female , Fluconazole/therapeutic use , Germany , Humans , Onychomycosis/drug therapy , Phylogeny , Tinea Capitis/drug therapy , Trichophyton
3.
Vet J ; 216: 18-24, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27687921

ABSTRACT

The aim of this study was to examine the effects of preoperative carprofen on the cardiorespiratory, hormonal and metabolic stress response during umbilical surgery under isoflurane anaesthesia combined with local anaesthesia, in calves. A randomised, blinded experimental study was conducted in 24 calves. Carprofen (n = 12; 1.4 mg/kg) or physiological saline solution (controls; n = 12) was administered 1 h prior to surgery. Anaesthesia was induced with xylazine (0.1 mg/kg, IM) and, after the onset of sedation (i.e. after 5-8 min), ketamine was administered (2 mg/kg, IV). Anaesthesia was then maintained with isoflurane (ISO) in oxygen to effect and completed by infiltration of the incision line with 20 mL of 2% procaine. Cardiorespiratory, endocrine and metabolic parameters were examined before, during and after surgery at short intervals. In both groups, anaesthesia appeared adequate for the surgical intervention. Heart rate, stroke index and arterial blood pressure were significantly elevated after the onset of surgery. Oxygen partial pressure and oxygen delivery increased, while the oxygen extraction ratio decreased intraoperatively, ensuring sufficient oxygen supply. In the control group, the mean surge in serum cortisol concentrations tended to be higher (P = 0.089) and systemic vascular resistance (SVR) was significantly greater (P <0.05) than in the carprofen group during surgery. In conclusion, the anaesthetic protocol used in this study induced reliable analgesia in both groups. The lower serum cortisol levels and SVR may indicate a reduced surgical stress response in calves undergoing umbilical surgery under ISO anaesthesia after administering carprofen preoperatively.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Carbazoles/adverse effects , Cardiovascular Physiological Phenomena/drug effects , Cattle/physiology , Hydrocortisone/blood , Nociception/drug effects , Vascular Resistance/drug effects , Anesthesia, Inhalation/veterinary , Anesthetics, Inhalation/administration & dosage , Animals , Female , Isoflurane/administration & dosage , Male
5.
Appl Microbiol Biotechnol ; 98(18): 7793-802, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24943047

ABSTRACT

Economic and ecological reasons cause the industry to develop new innovative bio-based processes for the production of oil as renewable feedstock. Petroleum resources are expected to be depleted in the near future. Plant oils as sole substituent are highly criticized because of the competitive utilization of the agricultural area for food and energy feedstock production. Microbial lipids of oleaginous microorganisms are therefore a suitable alternative. To decrease production costs of microbial lipids and gain spatial independence from industrial sites of CO2 emission, a combination of heterotrophic and phototrophic cultivation with integrated CO2 recycling was investigated in this study. A feasibility study on a semi-pilot scale was conducted and showed that the cultivation of the oleaginous yeast Cryptococcus curvatus on a 1.2-L scale was sufficient to supply a culture of the oleaginous microalgae Phaeodactylum tricornutum in a 21-L bubble column reactor with CO2 while single cell oils were produced in both processes due to a nutrient limitation.


Subject(s)
Cryptococcus/metabolism , Fermentation/physiology , Lipids/biosynthesis , Microalgae/metabolism , Biomass
6.
Hautarzt ; 64(11): 846-9, 2013 Nov.
Article in German | MEDLINE | ID: mdl-24008933

ABSTRACT

Trichophyton (T.) species of Arthroderma (A.) benhamiae is a new emerging pathogen of dermatomycoses in children and adolescents. This zoophilic fungus seems to be more common than other zoophilic dermatophytes, e. g. Microsporum canis transmitted from cats to humans, zoophilic strains of T. interdigitale, and T. verrucosum as cause of ringworm of cattle. Trichophyton species of A. benhamiae is transmitted from guinea pigs (Cavia porcellus form. domestica) to human beings and causes highly inflammatory dermatomycoses both of the face and the scalp. When this dermatophyte produces purulent abscess-forming deep cutaneous infections of the scalp known as kerions, they are both a diagnostic and in particular a therapeutic challenge.


Subject(s)
Tinea Capitis/diagnosis , Tinea Capitis/microbiology , Trichophyton , Administration, Topical , Antifungal Agents/administration & dosage , Communicable Diseases, Emerging/diagnosis , Communicable Diseases, Emerging/drug therapy , Communicable Diseases, Emerging/microbiology , Humans , Male , Middle Aged , Naphthalenes/administration & dosage , Terbinafine , Tinea Capitis/drug therapy , Treatment Outcome
7.
Klin Padiatr ; 223(6): 378-85, 2011 Nov.
Article in German | MEDLINE | ID: mdl-22052638

ABSTRACT

BACKGROUND: Primary immunodeficiencies are potentially life-threatening diseases. Over the last years, the clinical phenotype and the molecular basis of an increasing number of immunological defects have been characterized. However, in daily practice primary immunodeficiencies are still often diagnosed too late. Considering that an early diagnosis may reduce morbidity and mortality of affected patients, an interdisciplinary guideline for the diagnosis of primary immunodeficiencies was developed on behalf of the Arbeitsgemeinschaft Pädiatrische Immunologie (API) and the Deutsche Gesellschaft für Immunologie (DGfI). METHODS: The guideline is based on expert opinion and on knowledge from other guidelines and recommendations from Germany and other countries, supplemented by data from studies that support the postulated key messages (level of evidence III). With the contribution of 20 representatives, belonging to 14 different medical societies and associations, a consensus-based guideline with a representative group of developers and a structured consensus process was created (S2k). Under the moderation of a representative of the Association of the Scientific Medical Societies in Germany (AWMF) the nominal group process took place in April 2011. RESULTS: The postulated key messages were discussed and voted on following a structured consensus procedure. In particular, modified warning signs for primary immunodeficiencies were formulated and immunological emergency situations were defined.


Subject(s)
Cooperative Behavior , Immunologic Deficiency Syndromes/diagnosis , Interdisciplinary Communication , Adult , Child , Early Diagnosis , Evidence-Based Medicine , Germany , Humans , Opportunistic Infections/diagnosis
8.
Praxis (Bern 1994) ; 97(5): 243-51, 2008 Mar 05.
Article in German | MEDLINE | ID: mdl-18548806

ABSTRACT

We investigated the nutritional habits of ultra-endurance runners before, during and after the Deutschlandlauf 2006 in Germany, from the north (Kap Arkona-Rügen) to the south (Lörrach), over 1,200 km and 17 stages. Twenty male ultra-runners completed a questionnaire about their nutrition before, during and after the race. In the 4 weeks, and the day before the race, 70% of the runners followed no special diet. In the morning before the start of a stage, the main nutrients were buns with jam, butter and cheese and the preferred drink was coffee. During the stages, the athletes preferred to consume bread, bananas and chocolate and preferably drank pure water, Apfelschorle and Coca Cola. In the evening, the athletes preferred to consume meat, noodles, pure water and beer. During the run, 40% of the athletes had a special desire for salty and fatty food and 10% a particular reluctance for sweet and carbohydrate-rich products. After the race, the runners preferred apples, vegetables, rice, bread, pure water, Apfelschorle and beer. Multi-vitamin products, multi-mineral products as well as magnesium were the preferred supplements before, during and after the race. We conclude that 70% of the ultra-endurance runners in the Deutschlandlauf 2006 followed no special diet before the race. Multi-vitamins, multi-minerals and magnesium were preferably consumed as ergogenic supplements. Before the start of a stage they ate a normal breakfast; during a stage they preferred carbohydrate-rich products and water; and in the evening after a stage they preferred to consume meat with a carbohydrate-rich nutrition and drank water as well as beer.


Subject(s)
Feeding Behavior/psychology , Physical Endurance/physiology , Running/physiology , Adult , Cross-Sectional Studies , Dietary Supplements/statistics & numerical data , Feeding Behavior/physiology , Feeding and Eating Disorders/epidemiology , Female , Gastrointestinal Diseases/epidemiology , Germany , Humans , Male , Middle Aged , Nutrition Surveys
9.
Br J Sports Med ; 42(4): 295-9; discussion 299, 2008 Apr.
Article in English | MEDLINE | ID: mdl-17599951

ABSTRACT

OBJECTIVE: To investigate the association of anthropometric parameters to race performance in ultra-endurance runners in a multistage ultra-endurance run. DESIGN: Descriptive field study. SETTING: The Deutschlandlauf 2006 race in Germany, where athletes had to run 1200 km within 17 consecutive days. There were no interventions. SUBJECTS: In total, there were 19 male Caucasian ultra-endurance runners (mean (SD) 46.2 (9.6) years, 71.8 (5.2) kg, 179 (6) cm, BMI 22.5 (1.9) kg/m(2)). MAIN OUTCOME MEASUREMENTS: Determination of body mass, body height, length of lower limbs, skin-fold thicknesses, circumference of limbs, body mass index (BMI), percentage skeletal muscle mass (%SM), and percentage body fat (%BF) in 19 successful finishers in order to correlate anthropometric parameters with running performance. RESULTS: A significant association of upper arm circumference with the total running time was found (p<0.05, r2 = 0.26). No significant association was found with the directly measured anthropometric properties body height, body mass, average skin-fold thickness and the circumference of thigh and calf (p>0.05). Furthermore, no significant association was observed between the running time and the calculated parameters BMI, %BF, and %SM (p>0.05). CONCLUSIONS: In an ultra-endurance run over 1200 km within 17 consecutive days, circumference of the upper arm was the only factor associated with performance in well-experienced ultra-endurance runners. Body mass, BMI, body height, length of limbs, skin-fold thicknesses, circumference of limbs and the calculated percentage body composition of skeletal muscle mass and body fat showed no association with running performance.


Subject(s)
Anthropometry , Arm/anatomy & histology , Athletic Performance/physiology , Physical Endurance/physiology , Running/physiology , Adult , Body Composition , Body Mass Index , Humans , Male , Middle Aged , Skinfold Thickness
11.
J Oral Rehabil ; 29(9): 799-804, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12366531

ABSTRACT

The aim of the present in vitro study was to evaluate the effect of carbamide peroxide (CP) bleaching on fluoride uptake in enamel. Additionally, the susceptibility for erosion in bleached and fluoridated enamel was tested. Each four enamel specimens were prepared from 44 bovine incisors. The four samples gained from each tooth were distributed among four groups (A-D) of 44 specimens each: A: (unbleached/unfluoridated) served for determination of baseline fluoride concentration; B: (unbleached/fluoridated) four times in 2000 ppm NaF solution (2 min); C: (bleached/unfluoridated) four times in 10% CP (8 h); D: (bleached/fluoridated) four times in 10% CP and fluoridation. In 22 specimens of each group both KOH-soluble and structurally bound fluoride were determined in the outermost 30 micro m of the enamel. In the remaining specimens erosions were induced by immersing the samples in 5 mL of 1% citric acid (20 min) and microhardness was evaluated before and after demineralization. Statistical analysis showed that KOH-soluble fluoride uptake was similar for group B and D specimens. Structurally bound fluoride uptake after fluoride application in unbleached samples was significantly higher than in bleached ones. Bleaching only resulted in a highly significant fluoride loss. In all samples erosion caused a significant microhardness loss. The study showed that pre-treatment of enamel with CP followed by fluoridation does not improve erosive resistance. Moreover the study reveals that CP treatment decreases concentration of structurally bound fluoride in enamel which could not be outweighed by fluoridation with 2000 ppm NaF. It is concluded that it is not feasible to improve fluoride uptake in enamel with a pre-treatment with 10% CP.


Subject(s)
Dental Enamel/drug effects , Peroxides/pharmacology , Sodium Fluoride/pharmacokinetics , Tooth Erosion/prevention & control , Urea/analogs & derivatives , Urea/pharmacology , Analysis of Variance , Animals , Carbamide Peroxide , Cattle , Dental Enamel/metabolism , Drug Combinations , Hardness/drug effects , Hydroxides/chemistry , Peroxides/adverse effects , Potassium Compounds/chemistry , Sodium Fluoride/chemistry , Sodium Fluoride/therapeutic use , Statistics, Nonparametric , Urea/adverse effects
13.
J Exp Bot ; 52(358): 1041-9, 2001 May.
Article in English | MEDLINE | ID: mdl-11432920

ABSTRACT

Dionaea is a highly specialized carnivorous plant species with a unique mechanism for insect capture. The leaf is converted into an osmotically driven trap that closes when an insect triggers sensory trichomes. This study investigates the significance of insect capture for growth of Dionaea at different successional stages after a fire, under conditions where the prey is highly variable in its isotope signature. The contribution of insect-derived nitrogen (N) was estimated using the natural abundance of 15N. In contrast to previous 15N studies on carnivorous plants, the problem emerges that delta15N values of prey insects ranged between -4.47 per thousand (grasshoppers) and +7.21 per thousand (ants), a range that exceeds the delta15N values of non carnivorous reference plants (-4.2 per thousand) and soils (+3 per thousand). Thus, the isotope-mixing model used by Shearer and Kohl to estimate the amount of insect-derived N is not applicable. In a novel approach, the relationships of delta15N values of different organs with delta15N of trapping leaves were used to estimate N partitioning within the plant. It is estimated that soon after fire approximately 75% of the nitrogen is obtained from insects, regardless of plant size or developmental stage. The estimates are verified by calculating the average isotope signatures of insects from an isotope mass balance and comparing this with the average measured delta15N values of insects. It appears that for Dionaea to survive and reach the flowering stage, seedlings must first reach the 6th-leaf rosette stage, in which trap surface area nearly doubles and facilitates the capture of large insects. Large amounts of nitrogen thus made available to plants may facilitate an enhanced growth rate and the progressive production of additional large traps. Dionaea reaches a maximum abundance after fire when growth of the competing vegetation is suppressed. About 10 years after fire, when grasses and shrubs recover, Dionaea becomes overtopped by other species. This would not only reduce carbon assimilation but also the probability of catching larger prey. The amount of insect-derived nitrogen decreases to 46%, and Dionaea becomes increasingly dependent on N-supply from the soil. Competition for both light and N may cause the near disappearance of Dionaea in older stages of the fire succession.


Subject(s)
Insecta/metabolism , Magnoliopsida/metabolism , Nitrogen/metabolism , Animals , Carbon/metabolism
14.
Article in English | MEDLINE | ID: mdl-9669086

ABSTRACT

Regeneration experiments in Hydra have shown that lithium long-term treatment apparently causes a transformation of prospective head into foot tissue. Although lithium ions are known to interfere with the PI-PKC signal-transduction system and evidence has been provided that this system plays a role in pattern formation in Hydra, its role in mediating the lithium effect on patterning is still obscure. The present study provides evidence that H2O2 and presumably also lipid hydroperoxides mediate the lithium effects. First, the perturbation of pattern formation is strikingly stronger in the strain Hydra vulgaris than in Hydra magnipapillata, and similar strain-specific differences are found in the long lasting accumulation of hydroperoxides following lithium treatment. Second, the antioxidant vitamins E and C, which suppress peroxide accumulation, and the H2O2-degrading enzyme catalase significantly protect H. vulgaris from lithium effects. Lithium treatment also negatively affects overall DNA synthesis in a similar strain-specific manner, which, however, cannot be rescued by antioxidant vitamins. The lithium-activated source of peroxide production differs from another source, which generates peroxide in untreated polyps of both strains. The results suggest that lithium treatment-induced peroxide accumulation in H. vulgaris provokes a cytotoxic response showing foot-like characteristics. Nevertheless, a role of peroxides as messengers in pattern forming processes can not be excluded.


Subject(s)
Hydra/physiology , Hydrogen Peroxide/metabolism , Lithium/pharmacology , Regeneration/drug effects , Animals , Antioxidants/pharmacology , Catalase/pharmacology , Cell Differentiation , DNA/biosynthesis , Lipid Peroxides/metabolism , Peroxidase/metabolism , Vitamins/pharmacology
15.
J Infect Dis ; 176 Suppl 1: S24-8, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9240690

ABSTRACT

The influenza virus A hemagglutinin (HA) is a trimeric glycoprotein that contains 3-9 N-linked glycosylation sequons per subunit, depending on the strain. The location of these sites is determined by the nucleotide sequence of the HA gene, and, since the viral genome is replicated by an error-prone RNA polymerase, mutations, which add or remove glycosylation sites, occur at a high frequency. Mutations that are not lethal to the virus add to the structural diversity of the virus population. Factors that determine the glycosylation of the HA are reviewed herein, as are the effects of host-specific glycosylation on receptor binding, fusion activity, and antigenic properties of the virus. Effects of host-specific glycosylation and selection on virulence and on vaccine efficacy and surveillance are discussed. In addition, inadequacies in our understanding of HA glycosylation and its effects on host range are emphasized.


Subject(s)
Hemagglutinin Glycoproteins, Influenza Virus/metabolism , Animals , Glycosylation , Hemagglutinin Glycoproteins, Influenza Virus/chemistry , Humans , Orthomyxoviridae/pathogenicity , Structure-Activity Relationship , Virulence
16.
J Biol Chem ; 272(7): 4027-36, 1997 Feb 14.
Article in English | MEDLINE | ID: mdl-9020110

ABSTRACT

We have characterized the glycans at individual sites on the hemagglutinin of three influenza A variants to obtain information on the role of cell-specific glycosylation in determining the receptor binding properties of this virus. The variants differ in whether they have a glycosylation site at residue 129 on the tip of the hemagglutinin and whether amino acid 184 (near to the receptor binding site) is His or Asn. We found that all sites on each variant are glycosylated in Madin-Darby bovine kidney cells, that the glycosylation is site-specific, and that the glycans at the same site in each variant are highly similar. One site that is buried in the hemagglutinin trimer contains only oligomannose glycans. The remaining sites carry complex glycans of increasing size as the distance of the site from the viral membrane decreases. Most of these complex glycans are terminated with alpha-galactose residues, a consequence in bovine cells of the removal of terminal sialic acids by the viral neuraminidase. Although the glycans at residue 129 are among the smallest on the molecule, they are large enough to reach the receptor binding pocket on their own and adjacent monomers. The results suggest that the reduction in receptor binding observed with Madin-Darby bovine kidney cell-grown virus is due to the combined effect of large complex glycans at the tip of the hemagglutinin and a His to Asn substitution close to the receptor binding pocket.


Subject(s)
Hemagglutinin Glycoproteins, Influenza Virus/metabolism , Amino Acid Sequence , Animals , Binding Sites , Carbohydrate Conformation , Cattle , Cell Line , Chromatography, Affinity , Chromatography, Gel , Glycoside Hydrolases/metabolism , Glycosylation , Hemagglutinin Glycoproteins, Influenza Virus/chemistry , Molecular Sequence Data
17.
Dev Biol ; 166(1): 311-22, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7958455

ABSTRACT

We examined the effect of growth conditions upon mitotic p34cdc2 kinase and developmental competence in Acanthamoeba castellanii. At G2/M of the cell cycle p34cdc2 kinase activity peaks in level, and p34cdc2 is transiently in a complex with newly synthesized cyclin B and phosphorylated on tyrosine (pre-MPF). Developmental competence peaks in level slightly preceding p34cdc2 kinase activation and pre-MPF accumulation. Under adverse growth conditions p34cdc2 kinase activation and transient pre-MPF accumulation occur at a reduced G2 phase length and smaller cell size. Developmental competence is not expressed during the shortened G2 phase. Cycloheximide inhibits the precocious p34cdc2 kinase activation and both the precocious accumulation of cyclin B and tyrosine phosphorylation on p34cdc2. No-codazole inhibits the precocious p34cdc2 kinase activation as well; however, it does not affect the precocious accumulation of pre-MPF. Developmental competence increases in level during artificially elongated G2 phases. The results indicate that, first p34cdc2 kinase activation requires cyclin B in a complex with p34cdc2 and the presence of intact microtubuli, second establishment of competence requires a certain length of G2, and third the regulation of pre-MPF accumulation, and thus of cyclin B expression, plays a role in the relationship among growth condition, cell cycle progression, and expression of the developmental program.


Subject(s)
Acanthamoeba/cytology , CDC2 Protein Kinase/biosynthesis , Cell Cycle/physiology , Acanthamoeba/drug effects , Acanthamoeba/enzymology , Amino Acid Sequence , Animals , Antibodies , CDC2 Protein Kinase/analysis , CDC2 Protein Kinase/metabolism , Cell Cycle/drug effects , Chromatography, Affinity , Cyclins/analysis , Cyclins/biosynthesis , Cyclins/metabolism , Cycloheximide/pharmacology , Dose-Response Relationship, Drug , Enzyme Activation , G2 Phase , Kinetics , Mitosis , Molecular Sequence Data , Nocodazole/pharmacology , Peptides/chemical synthesis , Peptides/immunology , Phosphorylation , Theophylline/pharmacology , Time Factors , Vanadates/pharmacology
18.
J Virol ; 67(12): 7436-43, 1993 Dec.
Article in English | MEDLINE | ID: mdl-8230464

ABSTRACT

We determined the deduced amino acid sequences of two H1 duck influenza A virus hemagglutinins (HAs) and found that the consensus sequence of the HA, determined directly from virus recovered from the intestinal tract, remains unchanged through many generations of growth in MDCK cells and chicken embryos. These two duck viruses differ from each other by 5 amino acids and from A/Dk/Alberta/35/1976 (F. J. Austin, Y. Kawaoka, and R. G. Webster, J. Gen. Virol. 71:2471-2474, 1990) by 9 and 12 amino acids, most of which are in the HA1 subunit. They are antigenically similar to each other but different from the Alberta virus. We compared these H1 duck HAs with the HAs of human isolates to identify structural properties of this viral glycoprotein that are associated with host range. By comparison to the human H1 HAs, the duck virus HA sequences are highly conserved as judged by the small fraction of nucleotide differences between strains which result in amino acid substitutions. However, the most striking difference between these duck and human HAs is in the number and distribution of glycosylation sites. Whereas duck and swine viruses have four and five conserved glycosylation sites per HA1 subunit, none of which are on the tip of the HA, all human viruses have at least four additional sites, two or more of which are on the tip of the HA. These findings stress the role of glycosylation in the control of host range and suggest that oligosaccharides on the tip of the HA are important to the survival of H1 viruses in humans but not in ducks or swine.


Subject(s)
Consensus Sequence/genetics , Ducks/microbiology , Hemagglutinins, Viral/genetics , Influenza A virus/genetics , Amino Acid Sequence , Animals , Antigens, Viral/genetics , Antigens, Viral/immunology , Cells, Cultured , Consensus Sequence/immunology , Feces/microbiology , Genetic Variation , Glycosylation , Hemagglutinin Glycoproteins, Influenza Virus , Hemagglutinins, Viral/immunology , Influenza A virus/immunology , Models, Molecular , Molecular Sequence Data , Protein Processing, Post-Translational , Regulatory Sequences, Nucleic Acid/genetics , Selection, Genetic , Sequence Homology, Amino Acid
19.
Glycoconj J ; 9(2): 63-6, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1344709

ABSTRACT

Variations in the amino acid sequence of RNA virus envelope glycoproteins can cause changes in their antigenicity and can alter the host-cell tropism of the virus and the degree of virulence which it exhibits. Such changes may alter the course and outcome of viral diseases, either directly because of changes in the biological properties of the glycoproteins or indirectly through effects on immune surveillance and vaccine efficacy. The nature and extent of glycosylation of the surface glycoproteins of RNA viruses have also been implicated in such phenotypic alterations. It follows therefore that the 'plasticity' of the viral genome and the host-encoded glycosylation machinery combine to create populations of highly diverse viruses. This diversity is considered to be responsible for survival of these viruses in a variety of biological niches and for their ability to overcome the inhibitory effects of neutralizing antibodies and antiviral agents. In this article we discuss the implications of the inter-relationship between these two mechanisms for the generation of diversity.


Subject(s)
Glycoproteins/physiology , Viral Proteins/physiology , Glycoproteins/genetics , Glycosylation , Oligosaccharides/metabolism , RNA Viruses/genetics , Viral Proteins/genetics
20.
J Virol ; 65(6): 3022-8, 1991 Jun.
Article in English | MEDLINE | ID: mdl-2033664

ABSTRACT

We have previously characterized an influenza A (H1N1) virus which has host-dependent growth and receptor binding properties and have shown that a mutation which removes an oligosaccharide from the tip of the hemagglutinin (HA) by changing Asn-129 to Asp permits this virus to grow to high titer in MDBK cells, (C. M. Deom, A. J. Caton, and I. T. Schulze, Proc. Natl. Acad. Sci. USA 83:3771-3775, 1986). We have now isolated monoclonal antibodies specific for the mutant HA and have used escape mutants to identify alterations in HA sequence which reduce virus yields from MDBK cells without reducing those from chicken embryo fibroblasts. Two types of escape mutants which grow equally well in chicken embryo fibroblasts were obtained. Those with the parent phenotype contain Asn at residue 129 and are glycosylated at that site. Those with the mutant phenotype are unchanged at residue 129 but have a Gly to Glu substitution at residue 158, which is close to residue 129 on the HA1 subunit. Binding assays with neoglycoproteins containing N-acetylneuraminic acid in either alpha 2,3 or alpha 2,6 linkage to galactose showed that the MDBK-synthesized oligosaccharides at Asn-129 reduce binding to both of these receptors, leaving the HA's preference for alpha 2,6 linkages unchanged. Glu at residue 158 greatly reduces binding to both receptors without reducing virus yields from MDBK cells. We conclude that changes in the receptor binding properties of the HA can result either from direct alteration of the HA protein by host cell glycosylation or from mutations in the HA gene and that these changes generate heterogeneity that can contribute to the survival of influenza A virus populations in nature.


Subject(s)
Hemagglutinins, Viral/genetics , Influenza A virus/genetics , Receptors, Virus/genetics , Amino Acids/genetics , Animals , Antibodies, Monoclonal/genetics , Carbohydrate Conformation , Cells, Cultured , Galactose/chemistry , Glycosylation , Hemagglutinin Glycoproteins, Influenza Virus , Hemagglutinins, Viral/chemistry , Hemagglutinins, Viral/immunology , Mutation , N-Acetylneuraminic Acid , Protein Conformation , Receptors, Virus/metabolism , Sialic Acids/chemistry , Viral Envelope Proteins/chemistry , Viral Envelope Proteins/genetics , Viral Envelope Proteins/immunology
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