Serological Studies of an Acid-Labile O-Polysaccharide of Proteus vulgaris OX19 Lipopolysaccharide Using Human and Rabbit Antibodies

In a Weil-Felix test, sera from patients infected with Rickettsia sp. agglutinate Proteus OX types of bacteria and Proteus lipopolysaccharide (LPS) are responsible for the cross-reaction. Data on the character of LPS of one of the OX group strains, Proteus vulgaris OX19, are contradictory, and it remained unclear whether it has an O-polysaccharide (OPS) and is thus LPS of the smooth type (S) or not (rough-type LPS). Our studies showed that P. vulgaris OX19 (strain PZH-24) produces a smooth-type LPS that contains a long-chain OPS, but it undergoes depolymerization during mild acid hydrolysis conventionally used for LPS delipidation and loses the serological activity. An elucidation of the complete structure of OPS demonstrated the presence of a glycosyl phosphate linkage responsible for the acid-lability of the polysaccharide chain. In ELISA, both IgM type antibodies in a Weil-Felix test with human anti-Rickettsia typhi sera and rabbit anti-P. vulgaris OX19 antibodies reacted with OPS. Rabbit antibodies did not inhibit the cross-reaction with human antibodies and thus bind to different epitopes.     

Type‐II histone deacetylases: elusive plant nuclear signal transducers

Since the beginning of the 21st century, numerous studies have concluded that the plant cell nucleus is one of the cellular compartments that define the specificity of the cellular response to an external stimulus or to a specific developmental stage. To that purpose, the nucleus contains all the enzymatic machinery required to carry out a wide variety of nuclear protein post‐translational modifications (PTMs), which play an important role in signal transduction pathways leading to the modulation of specific sets of genes. PTMs include protein (de)acetylation which is controlled by the antagonistic activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). Regarding protein deacetylation, plants are of particular interest: in addition to the RPD3‐HDA1 and Sir2 HDAC families that they share with other eukaryotic organisms, plants have developed a specific family called type‐II HDACs (HD2s). Interestingly, these HD2s are well conserved in plants and control fundamental biological processes such as seed germination, flowering or the response to pathogens. The aim of this review was to summarize current knowledge regarding this fascinating, but still poorly understood nuclear protein family.     

The plagiosaurid temnospondyl Plagiosuchus pustuliferus (Amphibia: Temnospondyli) from the Middle Triassic of Germany: anatomy and functional morphology of the skull

The cranial anatomy of the plagiosaurid temnospondyl Plagiosuchus pustuliferus, from the Middle Triassic of Germany, is described in detail on the basis of a newly discovered skull and mandibular material. The highly derived skull is characterized by huge orbitotemporal fenestrae, a reduction of the circumorbital bones – the prefrontal, postfrontal and (probably) postorbital are lost – and the expansion of the jugal to occupy most of the lateral skull margin. Ventrally the extremely long subtemporal vacuities correlate with the elongate adductor fossa of the mandible. The dentition is feebly developed on both skull and mandible. Ossified ?ceratobranchials and ‘branchial denticles’ indicate the presence of open gills clefts in life. The remarkably divergent cranial morphology of P. pustuliferus highlights the extraordinary cranial diversity within the Plagiosauridae, probably unsurpassed within the Temnospondyli. Specific structural aspects of the skull – including an extremely short marginal tooth row, feeble dentition and an elongated chamber for adductor musculature – together with evidence for a hyobranchial skeleton, suggests that P. pustuliferus utilized directed suction feeding for prey capture. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 348–373.     

Trypanosoma cruzi: Interaction with Vertebrate Cells. DNA Synthesis and Growth of Intracellular Amastigotes and their Relationship to Host Cell DNA Synthesis and Growth

SYNOPSIS DNA synthesis of intracellular Trypanosoma cruzi amastigotes, following the infection of bovine embryo skeletal muscle (BESM) cells, was studied by autoradiography. After penetration, there was a prereplicative lag period (∼12 h) followed by a synchronous round of DNA synthesis which was found to be independent of parasite number/BESM cell and the host cell DNA synthesis cycle. Parasite reproduction occurred, for the first time, at ∼ 21 h postinfection. It was concluded that T. cruzi trypomastigotes are in the G₁/G, phase of their cell division cycle and that after penetration parasite reproduction occurs independent of events controlling host cell DNA synthesis and growth. The early synchronous growth of intracellular amastigotes should facilitate further studies on the biochemical events controlling trypomastigote-to-amastigote transformation and amastigote reproduction. A further application is envisaged for studies on the mode of action of drugs with trypanocidal activity.     

Trypanosoma cruzi: Flow Cytometric Analysis. I. Analysis of Total DNA/Organism by Means of Mithramycin-Induced Fluorescence1,2

ABSTRACT. Total DNA/organism was determined by flow cytometry on stocks of 33 single-cell-isolate clones and one strain of mithramycin-stained Trypanosoma cruzi. Interstrain differences in mean total DNA/group of 34% and interclone differences in total DNA/organism of 41% were found. Microspectrofluorometric analyses of the trypomastigote stage of selected clones confirmed the flow cytometry data and indicated that the total DNA/organism differences were due to differences in DNA of both the nucleus and kinetoplast with the nucleus being the major contributing factor. These data imply that the potential for genetic diversity in T. cruzi may be very large.     

Text messaging: an innovative method of data collection in medical research

Background

The ubiquitous use of mobile phones in sending and receiving text messages has become a norm for young people. Undeniably, text messaging has become a new and important communication medium not only in the social realm but in education as well. The aim of this study is to evaluate the effectiveness of using text messaging as a means to collect data for a medical research project.A cross sectional study was carried out during a double blind, randomized controlled trial to assess the efficacy and safety of a probiotic in the management of Irritable Bowel Syndrome (IBS). The study aim was to assess the response rate of weekly symptom reports via Short Message Service (SMS). The subjects were undergraduates in a private medical university in Malaysia. They were identified through a previous university wide study as suffering from IBS based on Rome III criteria. The subjects were randomly assigned to either the treatment arm receiving a daily probiotic, or the placebo arm. They were required to score their symptoms using eight-item-questionnaires at baseline, and thereafter weekly, for a total of 8 weeks. All subjects were given the choice to communicate their symptom scores by text messaging via mobile phones or by email. SMS text messages were sent to remind trial subjects to attend face-to-face visits and to complete a paper based 34-item-questionnaires on IBS quality of life assessment at baseline and at end of 8 weeks.

Findings

The response rate of weekly symptom scores via Short Message Service (SMS) from a total of 38 subjects was 100%. Through the study, 342 reports were submitted: 33.3% of these were received on the due date without reminder, 60.0% one day after the deadline, after a single reminder, 6.1% 2-3 days after the deadline, after 2-3 reminders and 0.6% 5 days after the deadline, after SMS, phone reminder and face-to-face encounter. All SMS symptom reports, whether on time or late, were complete. With the help of SMS reminder, all trial subjects completed the paper based IBS quality of life assessment at baseline and at end of study.

Conclusions

This study found using text messaging via mobile phone an excellent instrument for collecting weekly symptom reports in response to trial medication, reminding trial subjects to attend face to face visits and completing more complex paper based evaluation. The 100% response rate of weekly symptom reports was facilitated by using simple number codes for SMS submission.

Trial Registration

Not appropriate.