Biomedical subjects

Elzbieta Nowak

Publications and source records attributed to Elzbieta Nowak.

10 recordsLinked to original sources

PubMed2006

The structural basis of signal transduction for the response regulator PrrA from Mycobacterium tuberculosis.

The structure of the two-domain response regulator PrrA from Mycobacterium tuberculosis shows a compact structure in the crystal with a well defined interdomain interface. The interface, which does not include the interdomain linker, makes the recognition helix and the trans-activation loop of the effector domain inaccessible for interaction with DNA. Part of the interface involves hydrogen-bonding interactions of a tyrosine residue in the receiver domain that is believed to be involved in signal transduction, which, if disrupted, would destabilize the interdomain interface, allowing a more extended conformation of the molecule, which would in turn allow access to the recognition helix. In solution, there is evidence for an equilibrium between compact and extended forms of the protein that is far toward the compact form when the protein is inactivated but moves toward a more extended form when activated by the cognate sensor kinase PrrB.

Adaptation, Physiological↗

PubMed2006

Structural and functional aspects of the sensor histidine kinase PrrB from Mycobacterium tuberculosis.

We describe the solution structures of two- and three-domain constructs of the sensor histidine kinase PrrB from Mycobacterium tuberculosis, which allow us to locate the HAMP linker relative to the ATP binding and dimerization domains. We show that the three-domain construct is active both for autophosphorylation and for phosphotransfer to the cognate response regulator, PrrA. We also describe the high-resolution crystal structure of the catalytic domain alone, and we show that, in solution, it binds ATP. The conformational flexibility of this domain is discussed and related to other structural information.

Adenosine Triphosphate↗

PubMed2005

A novel two-component system found in Mycobacterium tuberculosis.

We report the identification of a novel two-component system in Mycobacterium tuberculosis. We show that the putative histidine kinase with the genomic locus tag Rv3220c is able to self-phosphorylate in the presence of Mg2+/ATP and subsequently transfer the phosphoryl group to a novel response regulator PdtaR. This creates a biochemical link between the two proteins and establishes a newly identified two component system, which acts at the level of transcriptional antitermination. We also suggest that this system has potential for the development of lead compounds for inhibition of phosphotransfer.

Bacterial Proteins↗

PubMed2004

Anatomical and histological data on the ciliary ganglion in the Egyptian spiny mouse (Acomys cahirinus Desmarest).

The morphology and topography of the ciliary ganglion in the Egyptian spiny mouse were studied with use of histochemical and histological techniques. The ciliary ganglion of the Egyptian spiny mouse consisted of between 3 and 4 agglomerations of nerve cells. The largest was situated at the point where the ventral branch of the oculomotor nerve divides into two branches. The next two smaller aggregations were located on the superior and lateral surfaces of the optic nerve where it crossed the oculomotor nerve. From the main agglomerations of neurocytes arose between 3 and 4 intensively stained postganglionic cholinergic fibres. These followed the optic nerve to the eyeball. On the cross-sections of these bundles small agglomerations of neurocytes were observed. These decreased in size to only 2 or 3 cells towards the sclera. The ganglionic neurocytes in the largest ganglion varied from 15 to 30 microm in diameter. They were distributed uniformly over the whole surface of the sections. All the ganglia had connective capsules.

Animals↗

PubMed2003

A comparative study on the morphology and topography of the ciliary ganglion in midday gerbil (Meriones meridianus) and turtle (Agrionemys horsfieldii).

The morphology and topography of the ciliary ganglia in the midday gerbil and turtle were studied with use of histochemical and histological techniques. The ciliary ganglion of the midday gerbil consisted of two cell agglomerations: the main ganglion and the accessory ganglion. The main ganglion was situated in the orbit and usually closely attached to the nerve for the inferior oblique muscle. The short ciliary nerves arose from the superior end of the main ganglion and reached the orbit. The accessory ciliary ganglion was smaller than the main ganglion. Usually it was attached to short ciliary nerves. The ganglionic neurocytes, 25.97 microm in diameter, were distributed regularly over the entire surface of the main ganglion. They typically had a single clear nucleus. The ciliary ganglion in the turtle formed a characteristic triangular structure on the inferior branch of the oculomotor nerve. The histological examination showed a small number of nerve cells in comparison to the nerve fibres. The neurocytes were placed mainly in the nasal part of ganglion and they had an irregular arrangement. The average diameter of neurons was 23.55 microm. Significant differences in density of ganglionic components in both species were observed. In midday gerbil the cells were densely packed and took up about 80% of a cross-section, while, in the turtle, neurocytes were located mainly in the surface part of ganglion.

Animals↗

PubMed2003

The AChE-positive ganglia in the trachea and bronchi of the cat.

The tracheal and bronchial parasympathetic ganglia in the cat were studied using the histochemical-tiocholine method of Koelle and Friedenwald and histological techniques. Intensively stained AChE-positive nerve structures, i.e., ganglia and nerve fibres on the wall of the trachea and bronchi, were observed. The ganglia were situated mainly on the dorso-lateral surface of these organs, but they were also present on the ventral surface. The largest ganglia were found in the vicinity of the vagus nerve branches and on the surface of the tracheal smooth muscle. Numerous ganglia (95-210) of different sizes (40 x 230 microm to 260 x 520 microm) and shapes (spindle, longitudinal, oval, elliptical and multiform) were interconnected by nerve fibres and formed a dense ganglionated plexus. The ganglia forming this nerve structure were located mainly on the level of intercartilaginous spaces. They received the nerve branches from the cervical and the upper thoracic branches of vagus nerve and cervical and upper thoracic segments of the sympathetic trunk. Similar AChE-positive ganglionated plexus containing 28-33 ganglia connected by nerve fibres was observed on the posterior wall of the bronchi. Histological investigations confirmed the presence of fascicles of nerve fibers and nerve cells aggregations in the external membrane of the trachea and bronchi. The ganglia consisted of 2-25 cells on the cross-section. They were located mainly on the level of intercartilaginous spaces and contained (except ganglionic neurocytes, nerve fibres) satellite cells and small blood vessels. All the ganglia had thin connective capsule.

Acetylcholinesterase↗

PubMed2003

[Cytogenetic changes and their prognostic significance in elderly acute myeloid leukemia].

Cytogenetic analyses were performed in 72 acute myeloid leukemia (AML) patients > or = 60 years old. Karyotype was normal in 35 (48.6%) patients (group III). 3 patients (4.2%) had favourable karyotype with t(15;17) as an isolated aberration (group IV). 21 patients (29.2%) had adverse karyotypes (group I) and 13 (18%) had intermediate karyotypes (group II). Adverse karyotypes were simple (< 3 aberrations), with add 3q, 5q-, 7q-, in 5 persons, and complex (> or = 3 aberrations) in 16. Karyotypes of 14 patients from the latter group contained > or = 5 aberrations. Laboratory and clinical data were comparable between groups with > or = 3 and with > or = 5 changes. In more than 2/3 complex karyotypes chromosome 5 and 7 aberrations also were found. AML clinical course of group II patients was more similar to that of group I than of groups III and IV. A frequency of complete remissions differed statistically between group I and the others and a frequency of complete and partial remissions together--between I + II and III + IV groups. Overall survival time differed statistically between all groups. There were significantly more patients with secondary AML in groups I and II than in group III. Analysis according to FAB did not show prognostic significance of this classification. Authors conclude that cytogenetics have a fundamental prognostic importance in AML of the elderly and should be taken into account in establishing therapeutic strategies.

Aged↗

PubMed2002

(S)-trans-cyclohexane-1,2-dicarboximide.

The molecule of the title compound, C(8)H(11)NO(2), contains a strained bicyclic system with a significantly twisted imide chromophore. The five-membered ring fragment containing the imide function is strongly puckered and adopts a half-chair conformation. The six-membered ring has a slightly distorted chair conformation. The molecules are joined by strong N-H.O and weak C-H.O hydrogen bonds into infinite chains.

Journal Article↗

PubMed2002

Metal binding to porcine pancreatic elastase: calcium or not calcium.

Porcine pancreatic elastase has been crystallized at slightly acidic pH under two similar but slightly different conditions. Diffraction data were collected at a wavelength of 1.5 A to a maximum resolution of 1.7 A. Both difference electron-density maps and anomalous difference electron-density maps suggest that in crystals grown from a sodium sulfate solution PPE binds Na(+) in its metal-binding site. In contrast, PPE binds Ca(2+) in crystals grown from a solution containing sodium citrate and calcium chloride. This observation is in contradiction to most PPE structures reported in the PDB. In addition to the metal-binding site, up to three other binding sites, which appear to be anion-binding sites, could be identified based on the observed anomalous intensity differences.

Animals↗

PubMed2002

Morphology, topography and cytoarchitectonics of the pterygopalatine ganglion in Egyptian spiny mouse (Acomys cahirinus, Desmarest).

Using the thiocholine method of Koelle and Friedenwald and histological techniques the pterygopalatine ganglion in Egyptian spiny mouse (Acomys cahirinus, Desmarest) was studied. The ganglion was found to be a single irregular cluster of neurocytes, situated on the medial surface of the maxillary nerve. The ganglion is composed of oval, elliptical and sometimes fusiform ganglionic neurones in compact arrangement without a thick connective-tissue capsule.

Animals↗