CTLA4 Autoimmunity-Associated Genotype Contributes to Severe Pulmonary Tuberculosis in an African Population

The gene of Cytotoxic T Lymphocyte-associated Antigen 4 (CTLA4), a negative regulator of T lymphocytes, contains a single-nucleotide polymorphism (SNP) at position +6230A->G (ct60A->G), which has been found associated with several autoimmune diseases and appears to reduce T-cell inhibitory activity. In Ghana, West Africa, we compared the frequencies of CTLA4 +6230 A/G and 6 haplotype-tagging SNPs in 2010 smear-positive, HIV-negative patients with pulmonary tuberculosis (TB) and 2346 controls matched for age, gender and ethnicity. We found no difference in allele frequencies between cases and controls. However, +6230A and a distinct CTLA4 haplotype and a diplotype comprising the +6230A allele were significantly less frequent among cases with large opacities in chest radiographs compared to those with small ones (P_{corrected [cor]} = 0.002, P_cor = 0.00045, P = 0.0005, respectively). This finding suggests that an increased T-cell activity associated with the CTLA4 +6230G allele contributes to pathology rather than to protection in pulmonary TB.     

High temporal variability of zooplankton,but only weak evidence for a near-bottom effect on composition and distribution in the deep Levantine Basin,eastern Mediterranean

Abundance and composition of the near-bottom zooplankton between 10 and 100 metres above the bottom (mab) were studied in the Levantine Basin, eastern Mediterranean, during four cruises of RV Meteor in June 1993, January 1998, April/May 1999 and October 2001. Copepoda made up 91% of all zooplankton caught. A strong dominance of one single species was observed on all cruises, with Lucicutia longiserrata reaching 50–90% of all Copepoda except in 1993, when Subeucalanus monachus was the most abundant species, with more than 90% of all Copepoda. The year 1993 was also exceptional in terms of total zooplankton abundance, being more than one order of magnitude higher than in the other years. Vertical differences in abundance and composition were small and did not indicate a near-bottom effect or a specialized benthopelagic zooplankton community in the layers sampled.     

Highly specialized Cretaceous beetle parasitoids (Ripiphoridae) identified with optimized visualization of microstructures

Extremely miniaturized longipedes insects (body length c. 0.3 mm) embedded in two pieces of Cretaceous amber from Myanmar are described and interpreted. Using inverted fluorescence and light microscopy for detailed analysis of microstructures, the inclusions were identified as primary larvae of the beetle family Ripiphoridae, subfamily Ripidiinae. While the structure of thoracic and abdominal segments including appendages corresponds well with the groundplan known in recent members of Ripidiinae, a curved prosternal ridge with prominent spines (each c. 5 μm), the reduced condition of stemmata and antennae and the lack of sharp mandibles are unique features within the entire family, apparently apomorphies of the longipedes larvae. A sinuate prosternal edge with a dense row of spines (prosternoctenidium) might be homologous with ‘head ctenidia’ in some previously described miniaturized conicocephalate larvae, but further investigation is needed. The morphological differences between the head of longipedes larvae and extant Ripidiinae are interpreted as adaptations to different groups of hosts and life strategies. Palaeoethology of the longipedes larvae is briefly discussed. In addition, the systematic placement of conicocephalate larvae from Canadian, Myanmar and Russian Cretaceous ambers, already interpreted by various authors as primary instars within Coleopterida (assigned to either Strepsiptera or to the coleopteran Tenebrionoidea: Ripiphoridae), is discussed.     

Application of a bioinformatics training delivery method for reaching dispersed and distant trainees

Many initiatives have addressed the global need to upskill biologists in bioinformatics tools and techniques. Australia is not unique in its requirement for such training, but due to its large size and relatively small and geographically dispersed population, Australia faces specific challenges. A combined training approach was implemented by the authors to overcome these challenges. The “hybrid” method combines guidance from experienced trainers with the benefits of both webinar-style delivery and concurrent face-to-face hands-on practical exercises in classrooms. Since 2017, the hybrid method has been used to conduct 9 hands-on bioinformatics training sessions at international scale in which over 800 researchers have been trained in diverse topics on a range of software platforms. The method has become a key tool to ensure scalable and more equitable delivery of short-course bioinformatics training across Australia and can be easily adapted to other locations, topics, or settings.     

Effects of glucose, tetrapyrroles and protein kinase C activators on cell proliferation in cultures of Saccharomyces cerevisiae

Abstract Saccharomyces cerevisiae was inoculated into a yeast nitrogen base with either glycerol or glucose as carbon source. Cell proliferation was followed by colony counts on agar medium. Cells in the glycerol-supplemented medium divided less than once in 10 days. When glucose, 6-deoxy-glucose or protoporphyrin IX was added, the cells had doubling times of about 24 h and increased in number to about 0.5 × 10⁶ cells ml⁻¹ Addition of either of the protein kinase C activators oleoyl-acetylglycerol or phorbol-12-myristate-13-acetate did not activate cell proliferation in the glycerol medium. However, when (i) glucose was combined with either protoporphyrin IX or chlorophyllin, or (ii) either protoporphyrin IX or chlorophyllin was combined with either of the protein kinase C activators, the cells had doubling times of about 12 h. Hence, (i) glucose can act as both a carbon source and a signalling molecule for proliferation, and (ii) two systems are involved in activating cell proliferation in S. cerevisiae : one operating through a protein kinase C system and another through a guanylate cyclase system.     

Introduction of the mercury transposon Tn501 into Rhizobium japonicum strains 31 and 110

Abstract Transposon Tn 501 , which encodes resistance to mercuric ions, was introduced into Rhizobium japonicum 110 and 31 by conjugal transfer. The transposon donor plasmid (pMD100) was able to mobilize into R. japonicum , but could not be maintained. Hg²⁺-resistant colonies were recovered at a frequency of 1.9 × 10⁻⁸/recipient for strain 110, and 1.7 × 10⁻⁷/recipient for strain 31. Presence of Tn 501 in Hg-resistant isolates was verified by Southern analysis and demonstrating transposition of Hg resistance. Transposon mutagenesis has been used to generate auxotrophic mutations at low frequency.