A rapid multiplex DNA suspension array method for Salmonella typhimurium subtyping using prophage-related markers

In this study we developed a preliminary proof of concept of method for Salmonella typhimurium subtyping using multiplex PCR-based phage locus typing and a multiplex Luminex DNA suspension array for product detection. Thirty markers were selected from prophages ST64B, ST64T, ST104, P22, Gifsy-1, sopEΦ and mostly phage-related AFLP fragments, and organised into two multiplex PCRs of 15 markers each. A two-group DNA suspension array was developed using a combination of flow cytometry and Luminex xMAP® technology. To assess its subtyping capability the method was applied to 438 non-epidemiological related S. typhimurium isolates of 56 phage types. Eighty-one profiles were generated. Isolates were divided into sixteen main prophage marker profile types. There was a strong tendency for isolates with the same phage type to have the same or closely related profiles and for groups of phage types to share the same profile. The discriminatory power of this method expressed as the Simpson's Index of Diversity (D) was 0.954. A panel of 12 selected markers achieved almost the same D value (0.952) as the 30 markers. This new method provides an alternative typing scheme for S. typhimurium epidemiological investigations. The developed array is in a high-throughput format which could easily be semi-automated, making the test fast and economical.     

CRYPTIC AND PSEUDO‐CRYPTIC DIVERSITY IN DIATOMS—WITH DESCRIPTIONS OF PSEUDO‐NITZSCHIA HASLEANA SP. NOV. AND P. FRYXELLIANA SP. NOV.1

A high degree of pseudo‐cryptic diversity was reported in the well‐studied diatom genus Pseudo‐nitzschia. Studies off the coast of Washington State revealed the presence of hitherto undescribed diversity of Pseudo‐nitzschia. Forty‐one clonal strains, representing six different taxa of the P. pseudodelicatissima complex, were studied morphologically using LM and EM, and genetically using genes from three different cellular compartments: the nucleus (D1–D3 of the LSU of rDNA and internal transcribed spacers [ITSs] of rDNA), the mitochondria (cytochrome c oxidase 1), and the plastids (LSU of RUBISCO). Strains in culture at the same time were used in mating studies to study reproductive isolation of species, and selected strains were examined for the production of the neurotoxin domoic acid (DA). Two new species, P. hasleana sp. nov. and P. fryxelliana sp. nov., are described based on morphological and molecular data. In all phylogenetic analyses, P. hasleana appeared as sister taxa to a clade comprising P. calliantha and P. mannii, whereas the position of P. fryxelliana was more uncertain. In the phylogenies of ITS, P. fryxelliana appeared to be most closely related to P. cf. turgidula. Morphologically, P. hasleana differed from most other species of the complex because of a lower density of fibulae, whereas P. fryxelliana had fewer sectors in the poroids and a higher poroid density than most of the other species. P. hasleana did not produce detectable levels of DA; P. fryxelliana was unfortunately not tested. In P. cuspidata, production of DA in offspring cultures varied from higher than the parent cultures to undetectable.     

SRPK1 inhibition in vivo: modulation of VEGF splicing and potential treatment for multiple diseases

SRPK1 (serine-arginine protein kinase 1) is a protein kinase that specifically phosphorylates proteins containing serine-arginine-rich domains. Its substrates include a family of SR proteins that are key regulators of mRNA AS (alternative splicing). VEGF (vascular endothelial growth factor), a principal angiogenesis factor contains an alternative 3' splice site in the terminal exon that defines a family of isoforms with a different amino acid sequence at the C-terminal end, resulting in anti-angiogenic activity in the context of VEGF165-driven neovascularization. It has been shown recently in our laboratories that SRPK1 regulates the choice of this splice site through phosphorylation of the splicing factor SRSF1 (serine/arginine-rich splicing factor 1). The present review summarizes progress that has been made to understand how SRPK1 inhibition may be used to manipulate the balance of pro- and anti-angiogenic VEGF isoforms in animal models in vivo and therefore control abnormal angiogenesis and other pathophysiological processes in multiple disease states.     

Relationships between leaf water status and transpiration of cowpea with progressive soil drying

Summary It was previously reported that leaf water status of cowpea (Vigna unguiculata) exhibited only small changes with progressive soil drying over extended periods of time. In these studies, under field conditions, it was demonstrated that when soil water was not limiting, xylem pressure potential ( _x ) exhibited a linear relationship with transpirational flux density with no obvious hysteresis. With progressive soil drying, values of _x and transpiration rate fell below the regression line established for nonlimiting soil conditions. It is proposed that paired measurements of _x and transpirational flux density made between midday and sunset can provide a measure of the extent to which soil conditions are limiting water uptake. The relation between _x and transpiration exhibits a family of curves, with more negative slopes and decreases in maximum transpiration rate indicating progressive limitation due to soil drying.     

Stomatal closure with soil water depletion not associated with changes in Bulk leaf water status

Summary It has previously been reported that canopy water loss by cowpea (Vigna unguiculata) decreases with small depletions in soil water. In these studies, under field conditions, it was demonstrated that with small changes in soil water status leaf conductance of cowpea decreases in a manner which is consistent with the sensitive regulation of canopy water loss.However, treatments which differed in leaf conductance, and presumably stomatal aperture, had similar leaf water potentials. It is hypothesized that the stomatal closure which results from soil water depletion is mediated by changes in root water status through effects on the flow of information from root to shoot. An efficient mechanism of this type could be partially responsible for the extreme drought avoidance exhibited by this plant.Dedicated to Dr. K. Springer     

Evaluation of the burden of unsuspected pulmonary tuberculosis and co-morbidity with non-communicable diseases in sputum producing adult inpatients

Background

A high burden of tuberculosis (TB) occurs in sub-Saharan African countries and many cases of active TB and drug-resistant TB remain undiagnosed. Tertiary care hospitals provide an opportunity to study TB co-morbidity with non-communicable and other communicable diseases (NCDs/CDs). We evaluated the burden of undiagnosed pulmonary TB and multi-drug resistant TB in adult inpatients, regardless of their primary admission diagnosis, in a tertiary referral centre.

Methodology/Principal Findings

In this prospective study, newly admitted adult inpatients able to produce sputum at the University Teaching Hospital, Lusaka, Zambia, were screened for pulmonary TB using fluorescent smear microscopy and automated liquid culture. The burden of pulmonary TB, unsuspected TB, TB co-morbidity with NCDs and CDs was determined. Sputum was analysed from 900 inpatients (70.6% HIV infected) 277 (30.8%) non-TB suspects, 286 (31.8%) TB suspects and 337 (37.4%) were already receiving TB treatment. 202/900 (22.4%) of patients had culture confirmed TB. TB co-morbidity was detected in 20/275 (7.3%) NCD patients, significantly associated with diabetes (P = 0.006, OR 6.571, 95%CI: 1.706–25.3). 27/202 (13.4%) TB cases were unsuspected. There were 18 confirmed cases of MDR-TB, 5 of which were unsuspected.

Conclusions/Significance

A large burden of unsuspected pulmonary TB co-morbidity exists in inpatients with NCDs and other CDs. Pro-active sputum screening of all inpatients in tertiary referral centres in high TB endemic countries is recommended. The scale of the problem of undiagnosed MDR-TB in inpatients requires further study.