The limits of cryptic diversity in groundwater: phylogeography of the cave shrimp Troglocaris anophthalmus (Crustacea: Decapoda: Atyidae)

Recent studies have revealed high local diversity and endemism in groundwaters, and showed that species with large ranges are extremely rare. One of such species is the cave shrimp Troglocaris anophthalmus from the Dinaric Karst on the western Balkan Peninsula, apparently uniform across a range of more than 500 kilometres. As such it contradicts the paradigm that subterranean organisms form localized, long-term stable populations that cannot disperse over long distances. We tested it for possible cryptic diversity and/or unexpected evolutionary processes, analysing mitochondrial (COI, 16S rRNA) and nuclear (ITS2) genes of 232 specimens from the entire range. The results of an array of phylogeographical procedures congruently suggested that the picture of a widespread, continuously distributed and homogenous T. anophthalmus was wrong. The taxon is composed of four or possibly five monophyletic, geographically defined phylogroups that meet several species delimitation criteria, two of them showing evidence of biological reproductive isolation in sympatry. COI genetic distances between phylogroups turned out to be a poor predictor, as they were much lower than the sometimes suggested crustacean threshold value of 0.16 substitutions per site. Most results confirmed the nondispersal hypothesis of subterranean fauna, but the southern Adriatic phylogroup displayed a paradoxical pattern of recent dispersal across 300 kilometres of hydrographically fragmented karst terrain. We suggest a model of migration under extreme water-level conditions, when flooded poljes could act as stepping-stones. In the north of the range (Slovenia), the results confirmed the existence of a zone of unique biogeographical conflict, where surface fauna is concordant with the current watershed, and subterranean fauna is not.     

The synthesis of N2,N6-substituted diaminopurine ribosides

A series of new 2,6-substituted diaminopurine riboside derivatives were synthesized by activation of protected xantosine with sulfonyl chlorides followed by treatment with various amines. The relationship between the reactivity of intermediates and the nature of the activating agents was studied.     

Optimizing Frozen Sample Preparation for Laser Microdissection: Assessment of CryoJane Tape-Transfer System?

Laser microdissection is an invaluable tool in medical research that facilitates collecting specific cell populations for molecular analysis. Diversity of research targets (e.g., cancerous and precancerous lesions in clinical and animal research, cell pellets, rodent embryos, etc.) and varied scientific objectives, however, present challenges toward establishing standard laser microdissection protocols. Sample preparation is crucial for quality RNA, DNA and protein retrieval, where it often determines the feasibility of a laser microdissection project. The majority of microdissection studies in clinical and animal model research are conducted on frozen tissues containing native nucleic acids, unmodified by fixation. However, the variable morphological quality of frozen sections from tissues containing fat, collagen or delicate cell structures can limit or prevent successful harvest of the desired cell population via laser dissection. The CryoJane Tape-Transfer System®, a commercial device that improves cryosectioning outcomes on glass slides has been reported superior for slide preparation and isolation of high quality osteocyte RNA (frozen bone) during laser dissection. Considering the reported advantages of CryoJane for laser dissection on glass slides, we asked whether the system could also work with the plastic membrane slides used by UV laser based microdissection instruments, as these are better suited for collection of larger target areas. In an attempt to optimize laser microdissection slide preparation for tissues of different RNA stability and cryosectioning difficulty, we evaluated the CryoJane system for use with both glass (laser capture microdissection) and membrane (laser cutting microdissection) slides. We have established a sample preparation protocol for glass and membrane slides including manual coating of membrane slides with CryoJane solutions, cryosectioning, slide staining and dissection procedure, lysis and RNA extraction that facilitated efficient dissection and high quality RNA retrieval from CryoJane preparations. CryoJane technology therefore has the potential to facilitate standardization of laser microdissection slide preparation from frozen tissues.     

Effect of Thyrotropin-Releasing Hormone and Its Synthetic Analogue Digipramine on Certain Indices of Hemostasis <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>

The effect of neuropeptide thyrotropin-releasing hormone (TRH) and its synthetic analogue digipramine on certain indices of blood coagulation and fibrinolysis were studied in vitro and in vivo. The peptides added to the pool of normal rat plasma at 10⁻¹⁰ to 10⁻³ M increased the procoagulant activity but had virtually no effect on fibrinolysis. Intravenous administration of TRH and digipramine increased the procoagulant activity of the blood and platelet aggregation but decreased fibrinolysis; digipramine had a more pronounced effect on the coagulation potential of the blood and a less pronounced effect on fibrinolytic indices as compared to TRH. Intranasal administration of the peptides did not change the pattern of their effect on indices of hemostasis although the effects became less pronounced.__________Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 3, 2005, pp. 311–315.Original Russian Text Copyright © 2005 by Grigorjeva, Golubeva.     

Functional activity of vasopressin analog desglycinamide-arginine-vasopressin

Original and published data on the functional activity of neurohypophyseal hormone vasopressin and its analog DGAVP were analyzed with a particular focus on the pattern of the peptide effect on the hemostatic system. The effects of the natural hormone and its synthetic analog on some indices of coagulation and fibrinolysis were compared. The effects of the peptides on the behavioral responses as well as on memory processes of animals are analyzed.     

Comparative investigation of the effect of vasopressin and of its structural analogue DGAVP on aggregation of blood platelets

In experiments in vitro, the effects of vasopressin and of its analogue DGVAP on aggregation of platelets are compared. Addition of peptides causes aggregation both in plasma rich in platelets both in humans and rats. In the human plasma DGVAP is a much stronger inductor of aggregation than vasopressin, whereas in the plasma of rats the effects are identical. Vasopressin and DGVAP considerably increase thrombin-induced aggregation of washed platelets of rats but do not influence ADP-induced aggregation of platelets. Thus, multifunctional action of these peptides on aggregation of platelets may depend both on their direct interaction with platelets and on a potential synergic action of peptides with other agonists.