Study of Molecular Karyotypes in Amoeboaphelidium protococcarum,the Endotrophic Parasite of Chlorophycean alga Scenedesmus

On the basis of the pulsed field gel electrophoresis (PFGE) technique, molecular karyotypes in Amoeboaphelidium protococcarum (the endotrophic parasite of chlorophycean algae, which combines protozoon- and fungus-type characters) were determined. Molecular karyotypes in the strains X1, X5, and X31, which differ in the host range and originate from Western, Central, and Eastern Euro-Asia respectively, demonstrate the intrageneric polymorphism—from 7 to 13 chDNA bands—with the estimated molecular size of 0.3–2.2 Mb were resolved, and the genome size was determined to be between 7.4 and 10.2 Mb. The molecular karyotype pattern in A. protococcarum is different from that in Protozoa. The low-grade distinction in molecular karyotypes between X1 and X5, on one hand, and high-grade distinction between X1/X5 and X31, on the other hand, makes it possible to place X31 in a separate taxon. Received: 24 June 1996 / Accepted: 1 August 1996     

Neurotransmitter and neuropeptide mechanisms responsible for the development of a withdrawal syndrome in morphine-dependent animals

The neurotransmitter and neuropeptide mechanisms responsible for the development of the morphine drug dependence and a withdrawal syndrome (WS) were studied in rats. Physical dependence and WS were found to develop against the background of restricted responsiveness of the adrenergic and dopaminergic systems. At the same time, the activity of the serotonin-, GABA-, vasopressin-, and oxytocinergic systems is suppressed at the WS. Agonists of opiate receptors, butorphanol and loperamid, were shown to improve the physical state of the animals with a WS. Similar action was found to be exerted by activators of the adrenergic system (ephedrine, phenylephrine), dopaminergic system (levoDOPA, apomorphine), and serotonergic system (tryptophan), as well as by neuropeptides, vasopressin and oxytocin.     

Macrokinetics of enzyme sorption on porous beads accompanied by complex formation with an immobilized ligand

A mathematical model has been proposed for enzyme sorption on porous beads accompanied by formation of a stable complex with an immobilized ligand. It has been experimentally verified by using the system trypsin (EC 3.2.21.4) - immobilized bovine basic polyvalent trypsin inhibitor on porous silica gel. The experimental results for kinetics of the non-specific/specific trypsin sorption on a carrier agree with the model. The value of the coefficient of trypsin diffusion in macroporous silica gel was calculated.     

Axial coordination of heme in ferric CcmE chaperone characterized by EPR spectroscopy

In Escherichia coli cytochrome c maturation requires a set of eight proteins including the heme chaperone CcmE, which binds heme transiently, yet covalently. Several variants of CcmE were purified and analyzed by continuous-wave electron paramagnetic resonance, electron nuclear double resonance, and hyperfine sublevel correlation spectroscopy to investigate the heme axial coordination. Results reveal the presence of a number of coordination environments, two high-spin heme centers with different rhombicities, and at least one low-spin heme center. The low-spin species was shown to be an artifact induced by the presence of available histidines in the vicinity of the iron. Both of the high-spin forms are five-coordinated, and comparison of the spectra of the wild-type CcmE with those of the mutant CcmE(Y134H) proves that the higher-rhombicity form is coordinated by Tyr134. The low-rhombicity (axial) form does not have a histidine residue or a water molecule as an axial ligand. However, we identified exchangeable protons coupled to the iron ion. We propose that the axial form can be coordinated by a carboxyl group of an acidic residue in the flexible domain of the protein. The two species would represent two different conformations of the flexible alpha-helix domain surrounding the heme. This conformational flexibility confers CcmE special dynamic properties that are certainly important for its function.     

The anatomy and ultrastructure of the suctorial organ of Solifugae (Arachnida)

Solifugae possess an evertable, adhesive pedipalpal organ (suctorial organ) at the tip of the distal tarsus of each pedipalp that is unique among arachnids. When inverted inside the pedipalp, the suctorial organ is covered with two cuticular lips, a dorsal upper lip and a ventral lower lip, but it can be protruded rapidly in order to facilitate grasping prey or climbing on bushes or even climbing on smooth surfaces due to its remarkable adhesive properties. In this study, the suctorial organs of different species from old world families Galeodidae and Karschiidae and new world families Ammotrechidae and Eremobatidae were investigated by means of light microscopy, scanning and transmission electron microscopy. In all representatives, the suctorial organ is formed by an evertable, cuticular pad with a complex internal stabilizing structure. The procuticle of this pad consists of a lattice-like basal plate and numerous stalked structures connected to this basal plate. The shafts of the stalked structures are regularly organized and ramify apically. The surface of the suctorial organ is constituted of a very thin epicuticle overlaying the ramifying apices forming ridges and furrows on the ventral side of the suctorial organ.     

15-prostaglandin dehydrogenase expression alone or in combination with ACSM1 defines a subgroup of the apocrine molecular subtype of breast carcinoma

Established histopathological criteria divide invasive breast carcinomas into defined groups. Ductal of no specific type and lobular are the two major subtypes accounting for around 75 and 15% of all cases, respectively. The remaining 10% include rarer types such as tubular, cribriform, mucinous, papillary, medullary, metaplastic, and apocrine breast carcinomas. Molecular profiling technologies, on the other hand, subdivide breast tumors into five subtypes, basal-like, luminal A, luminal B, normal breast tissue-like, and ERBB2-positive, that have different prognostic characteristics. An additional subclass termed "molecular apocrine" has recently been described, but these lesions did not exhibit all the histopathological features of classical invasive apocrine carcinomas (IACs). IACs make up 0.5-3% of the invasive ductal carcinomas, and despite the fact that they are morphologically distinct from other breast lesions, there are presently no standard molecular criteria available for their diagnosis and as a result no precise information as to their prognosis. Toward this goal our laboratories have embarked in a systematic proteomics endeavor aimed at identifying biomarkers that may characterize and subtype these lesions as well as targets that may lead to the development of novel targeted therapies and chemoprevention strategies. By comparing the protein expression profiles of apocrine macrocysts and non-malignant breast epithelial tissue we have previously reported the identification of a few proteins that are specifically expressed by benign apocrine lesions as well as by the few IACs that were available to us at the time. Here we reiterate our strategy to reveal apocrine cell markers and present novel data, based on the analysis of a considerably larger number of samples, establishing that IACs correspond to a distinct molecular subtype of breast carcinomas characterized by the expression of 15-prostaglandin dehydrogenase alone or in combination with a novel form of acyl-CoA synthetase medium-chain family member 1 (ACSM1). Moreover we show that 15-prostaglandin dehydrogenase is not expressed by other breast cancer types as determined by gel-based proteomics and immunohistochemistry analysis and that antibodies against this protein can identify IACs in an unbiased manner in a large breast cancer tissue microarray making them potentially useful as a diagnostic aid.     

Analysis of the Stridulation in Solifuges (Arachnida: Solifugae)

Stridulation in solifuges has not been investigated yet. We performed a comparative analysis of the stridulatory organs and sounds produced by juveniles of various developmental stages and adults (both sexes) of Galeodes caspius subfuscus Birula. The stridulatory organ is of similar morphology in all developmental stages. The sound that they produced was a broad frequency hissing, composed of one or two chirps with maximum at 2.4 kHz. The intensity of the sound was found to increase with body size. Otherwise, no differences were observed between stridulation in juvenile, male and female individuals. Therefore, we suggest that the stridulation in solifuges has primarily a defensive role. As solifuges are neither venomous nor unpalatable, they might imitate an accoustically aposematic organism that shares the same habitat and has similar circadian activity, e.g. vipers. It may also have an intraspecific function in reduction of cannibalistic tendencies.     

Parental care in captive red-backed vole (Clethrionomys rutilus)

Parental behavior in ten pairs of male and female red-backed voles, Clethrionomus rutilus, was studied under laboratory conditions. Significant sex differences were found in total time spent in the nest, time spent by adults alone in the nest, grooming time, and nest-building activity; in half of the males under study, the level of paternal care was extremely low. These findings indicate different paternal contributions of female and male red-backed voles into the rearing of young, in agreement with the spatial-ethological structure of populations of this species. Parental behavior of C. rutilus is discussed in comparison with that of other species of the subfamily Microtinae.     

Interactions in family pairs and parental care in captive steppe lemming (Lagurus lagurus)

Partner interactions and parental activities in pair-bonded male and female steppe lemmings (L. lagurus) were estimated under laboratory conditions. Interactions between adults in family pairs were found to be neutral or peaceful with rare agonistic contacts. Compared to other rodent species living in family groups, the frequency and duration of partner grooming in adults were found to be low, indicating relatively weak pair bonding in steppe lemmings. At the same time, males spend much more time with pups in the nest than females, but they are inferior to the latter in grooming (licking) and nest material delivery. Parental behavior of L. lagurus is discussed in comparison with that of other species of the subfamily Microtinae.