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Biomedical subjects

H Albrecht

Publications and source records attributed to H Albrecht.

At least 127 records · Page 7Linked to original sources
PubMed1991

Single amino acid substitutions in the B870 alpha and beta light-harvesting polypeptides of Rhodobacter capsulatus. Structural and spectral effects.

To obtain information on the structural and functional role of highly conserved amino acid residues in the B870 alpha and beta light-harvesting polypeptides of Rhodobacter capsulatus, site-directed mutagenesis was performed. 18 mutants with single amino acid substitutions at nine different positions in the B870 antenna polypeptides were prepared in a B800-850-lacking strain. The characterization of the resulting phenotypes was based on a quantification of the core-complex elements (reaction center, light-harvesting polypeptides, bacteriochlorophyll a and carotenoid) and the core-complex spectral characteristics (absorption maximum, absorption coefficient and fluorescence intensity). These data generally showed that strong structural effects were caused by the amino acid substitutions. Thus, the three tryptophan exchanges at the position alpha 8 resulted in either the absence of a core complex (alpha Trp8----Leu), the absence of the core antenna (alpha Trp8----Ala) or a reduction in the carotenoid content (alpha Trp8----Tyr). Likewise, the mutants alpha Pro13Gly (i.e. alpha Pro13----Gly), beta Gly10Val and alpha Phe23Ala demonstrated an abnormal protein/pigment ratio in the core antenna, while a drastically reduced antenna size resulted from the amino acid exchange beta Arg45Asp. In contrast to the structural effects, the absorption maxima and the fluorescence intensities of the mutant antennae differed only slightly from the wild type. The strongest blue shift of the bacteriochlorophyll a (8-11 nm) was induced by substitutions of the Trp at position alpha 43 (alpha Trp43----Ala, Leu or Tyr). Contrary to the other spectral effects, the absorption coefficient of bacteriochlorophyll a was strongly influenced by the amino acid substitutions and varied by 1.6-times less (beta Arg45Asp) and 1.3-times greater (alpha Phe25Ala) than normal. The antenna-free mutant, alpha Trp8Ala, yielded a high rate of B800-850 revertants during phototrophic growth, indicating a direct energy transfer from the B800-850 antenna to the reaction center in these strains. Although conditions for growth were generally observed to influence phenotypic expression, the structural as well as spectral effects were demonstrated to differ to the greatest extent between chemotrophically grown and phototrophically grown cells.

Amino Acid Sequence↗
PubMed1991

Visceral leishmaniasis in an HIV-infected patient: clinical features and response to treatment.

We report the case of 43-year-old homosexual patient with HIV infection and a history of travel to the Far East in whom visceral leishmaniasis was the first infectious complication. Symptoms were fever, malaise, weight loss, hepatosplenomegaly, generalized lymphadenopathy, and oral thrush. Laboratory abnormalities included a slight elevation of liver enzymes, impairment of liver function tests, leukocytopenia, anemia, hypergammaglobulinemia, and markedly depressed CD4(+)-cell counts. Despite initially successful treatment with pentavalent antimony, a relapse of leishmaniasis occurred after 7 months. Eradication of the infection was not achieved. Treatment was continued as a palliative chronic suppressive treatment with fortnightly pentamidine infusions. The clinical course was complicated by legionella pneumonia and the development of rapidly progressing Kaposi's sarcoma. The case is presented in detail, and the influence of HIV infection on the course of leishmaniasis is discussed.

AIDS Serodiagnosis↗
PubMed1991

Characterization and expression of a genomic pectin methyl esterase-encoding gene in Aspergillus niger.

The genomic pectin methylesterase (PME)-encoding gene (pmeA) from Aspergillus niger strain RH5344 was cloned by probing a genomic DNA library with a cDNA coding for PME. The recombinant phage clone was isolated and a 6-kb HindIII fragment was subcloned and characterized. The gene consists of seven exons and six introns. The nucleotide sequences of the coding regions were identical to those found in the pmeA cDNA. Cotransformation of A. niger was achieved with the vector, pAN7-1, and transformants were then tested for PME production. Transformants which produced more PME than the untransformed recipient strain were subjected to Southern-blot and Northern-blot analysis. The results show that there is a reasonable correlation between gene copy number, mRNA levels and PME production. PME was produced by A. niger transformants in an active 43-kDa form, which is similar to that of the mature protein isolated from the strain, RH5344. On the basis of the results of affinity labeling of PME with sugar-specific lectins and the amino acid sequence data, it has been revealed that PME is a glycoprotein and the protein-bound glycans are oligosaccharides with a high mannose content.

Affinity Labels↗
PubMed1991

Herpes simplex virus type-2 ulcers resistant to acyclovir in an AIDS patient--successful treatment with foscarnet.

The case of a 25-year-old homosexual man with large inguinal and perianal ulcers is reported. He had been pretreated extensively with acyclovir. Herpes simplex virus (HSV) was identified in the ulcer tissue by in-situ hybridization. No clinical improvement with acyclovir but a prompt response to foscarnet was noted. In a relapse after 11 weeks an acyclovir-resistant HSV type 2 was isolated. Again, a prompt response to foscarnet was noted. The case is presented in detail, and the clinical impact of resistance of HSV to acyclovir is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Liver abscesses due to Yersinia enterocolitica].

A 41-year-old man with type II diabetes for the past five years had for three weeks been suffering from high fever (up to 40 degrees), feeling of pressure in the upper abdomen, loss of weight, lack of appetite and increasing weakness. Ultrasound examination as an out-patient was suspicious of diffuse liver metastases from an unknown primary tumour. Ultrasonography and computed tomography after hospitalization suggested multiple liver abscesses. Fine-needle biopsy grew Yersinia enterocolitica. In addition, there was evidence of an asymptomatic intestinal Yersinia infection without septicaemia. After intravenous treatment with three times daily 5 g mezlocillin and three times daily 80 mg tobramycin the fever at first subsided, but the liver abscesses remained unchanged. When fever recurred a week later, cefotaxim, three times daily 2 g, was started. This led to complete regression of the abscesses within three weeks, and the patient has been free of symptoms since.

Adult↗
PubMed1990

Mycobacterium kansasii infection limited to skin and lymph node in a patient with AIDS.

The case of a 36-year-old HIV-1-positive patient is presented. After an episode of Pneumocystis carinii pneumonia and cytomegalovirus retinitis a pruritic lesion developed on the thigh with subsequent intracutaneous abscess formation and regional lymph-node enlargement. Mycobacterium kansasii was demonstrated in lymph-node and abscess material. With a tuberculostatic triple-drug regimen the lesions resolved completely. Cutaneous involvement in the course of non-tuberculous mycobacteriosis in the acquired immunodeficiency syndrome is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Homicide and psychiatry.

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Disruptive, Impulse Control, and Conduct Disorders↗
PubMed1989

A 37 kilodalton protein kinase associated with cauliflower mosaic virus.

The cauliflower mosaic virus (CaMV) particle-associated protein kinase (PK) was shown to be a 37 kD protein in activity gels. In vitro experimental data concerning virus dephosphorylation or hyperphosphorylation suggested a possible regulation mechanism of this PK. The origin of the enzyme, either virus-encoded or from a host cell, is discussed.

Brassica↗
PubMed1988

Cauliflower mosaic virus gene I product detected in a cell-wall-enriched fraction.

Gene I product of cauliflower mosaic virus was immunodetected in a cell-wall-enriched fraction from infected turnip leaves in addition to its detection in viroplasms and replication complexes. The immunoreaction was carried out with an antiserum raised against a 15 amino acid long synthetic peptide corresponding to the carboxy-terminus of potential gene I protein (P1). The presence of P1 in different subcellular fractions was investigated as a function of time during viral multiplication. At late infection times, P1 was found only in the cell-wall-enriched fraction.

Cell Wall↗