Microalgae: potential novel protein for sustainable human nutrition

To support a global population of ~10 billion people in 2050, dietary protein demand is forecast to increase 32-78% compared to 2017, requiring significantly higher planetary resources. Microalgae are an attractive sustainable protein source compared with current plant and animal sources. Benefits include mass scalability, low CO2 emissions, and significantly reduced land and freshwater use per unit protein. Microalgae are already used as food products and numerous species exhibit high total protein contents and well-balanced essential amino acid (EAA) compositions for human dietary requirements. Microalgae proteins are also bioavailable for human digestion, and downstream processing steps are likely to further enhance protein digestibility. Species, cultivation, and process/product optimisation are actively being developed to enhance their nutritional, social, and environmental benefits.

Sleep and cognition in South African patients with non-functioning pituitary adenomas

Strong lines of evidence in the neuroscience literature indicate that (a) healthy sleep facilitates cognitive processing, and (b) sleep disruption is associated with cognitive dysfunction. Despite the fact that patients with pituitary disease often display both disrupted sleep and cognitive dysfunction, few previous studies investigate whether these clinical characteristics in these patients might be related. Hence, we explored whether sleep disruption in patients with pituitary disease mediates their cognitive dysfunction. We recruited 18 patients with non-functioning pituitary adenomas (NFPA) and 19 sociodemographically matched healthy controls. They completed the Global Sleep Assessment Questionnaire (thus providing self-report data regarding sleep disruption) and were administered the Brief Test of Adult Cognition by Telephone, which assesses cognitive functioning in the domains of processing speed, working memory, episodic memory, inhibition, and reasoning. We found no significant differences in cognition between patients and controls. Furthermore, spectra of sleep disturbance did not differ significantly between patients and controls. Our data suggest that NFPA patients' cognition and sleep quality is relatively intact, and that sleep disruption does not mediate cognitive dysfunction. Larger studies should characterize sleep and cognition in patients with NFPA (and other pituitary diseases) to confirm whether disruption of the former mediates impairment in the latter.

Management of Type 2 Diabetes Mellitus and Kidney Failure in People with HIV-Infection in Africa: Current Status and a Call to Action

There is an increasing global burden of diabetes mellitus (DM) and chronic kidney disease (CKD), coupled with a high burden of people with HIV (PWH). Due to an increased lifespan on ART, PWH are now at risk of developing non-communicable diseases, including DM. Africa has the greatest burden of HIV infection and will experience the greatest increase in prevalence of DM over the next two decades. In addition, there is a rising number of people with CKD and progression to kidney failure. Therefore, there is an urgent need for the early identification and management of all 3 diseases to prevent disease progression and complications. This is particularly important in Africa for people with CKD where there is restricted or no access to dialysis and/or transplantation. This review focuses on the epidemiology and pathophysiology of the interaction between HIV infection and DM and the impact that these diseases have on the development and progression of CKD. Finally, it also aims to review the data on the management, which stems from the growing burden of all three diseases.

Outcome of COVID-19 infections in patients with adrenal insufficiency and excess

BACKGROUND

Information on clinical outcomes of coronavirus disease 19 (COVID-19) infection in patients with adrenal disorders is scarce.

METHODS

A collaboration between the European Society of Endocrinology (ESE) Rare Disease Committee and European Reference Network on Rare Endocrine Conditions via the European Registries for Rare Endocrine Conditions allowed the collection of data on 64 cases (57 adrenal insufficiency (AI), 7 Cushing's syndrome) that had been reported by 12 centres in 8 European countries between January 2020 and December 2021.

RESULTS

Of all 64 patients, 23 were males and 41 females (13 of those children) with a median age of 37 and 51 years. In 45/57 (95%) AI cases, COVID-19 infection was confirmed by testing. Primary insufficiency was present in 45/57 patients; 19 were affected by Addison's disease, 19 by congenital adrenal hyperplasia and 7 by primary AI (PAI) due to other causes. The most relevant comorbidities were hypertension (12%), obesity (n = 14%) and diabetes mellitus (9%). An increase by a median of 2.0 (IQR 1.4) times the daily replacement dose was reported in 42 (74%) patients. Two patients were administered i.m. injection of 100 mg hydrocortisone, and 11/64 were admitted to the hospital. Two patients had to be transferred to the intensive care unit, one with a fatal outcome. Four patients reported persistent SARS-CoV-2 infection, all others complete remission.

CONCLUSION

This European multicentre questionnaire is the first to collect data on the outcome of COVID-19 infection in patients with adrenal gland disorders. It suggests good clinical outcomes in case of duly dose adjustments and emphasizes the importance of patient education on sick day rules.

Reference intervals for biochemical analytes in transgender individuals on hormone therapy

BACKGROUND

Hormone therapy in transgender individuals may impact processes that lead to changes in biochemical analytes, and therefore reference intervals. Currently, few reference interval studies are available for the transgender population. We determined biochemical reference intervals for transgender individuals receiving hormone therapy.

METHODS

Our retrospective, laboratory-based, observational study included healthy transgender males (N = 24) and transgender females (N = 84) on hormone therapy. Various biochemical reference intervals were established for each cohort and compared to their cisgender counterparts.

RESULTS

We detected significant differences in reference intervals for sodium, 139-142 mmol/L vs. 136-145 mmol/L when comparing transgender males (TM) with cisgender males (CM). The following significant changes in upper reference limits (URL) for TM versus CM were detected, ALP (URL: 96 U/L vs. 128 U/L), GGT (URL: 27 U/L vs. 67 U/L) and testosterone (URL: 46.7 nmol/L vs. 29.0 nmol/L), respectively. Moreover, when comparing transgender female (TF) to cisgender female (CF), significant differences in creatinine (URL: 117 μmol/L vs. 90 μmol/L), albumin (lower reference limit: 41 g/L, vs. 35 g/L), AST (URL: 50 U/L vs. 35 U/L), ALP (URL: 118 U/L vs. 98 U/L) and oestradiol (URL: 934 pmol/L vs. 213 pmol/L) were noted, respectively. Significantly higher LDL-C was observed for TM on hormone treatment, compared to baseline (2.9 mmol/L vs. 2.2 mmol/L, p <0.01).

CONCLUSIONS

Biochemical results for TM and TF receiving hormone therapy can be evaluated against our transgender-specific reference intervals for some analytes, while others can be compared to their identified gender reference intervals.

Characteristics and Challenges of Primary Adrenal Insufficiency in Africa: A Review of the Literature

BACKGROUNDS

Africa comprises 54 countries with varying degrees of economic development. As with other healthcare systems, rare diseases such as adrenal insufficiency are neglected and poorly documented.

OBJECTIVES

We wished to explore primary adrenal insufficiency (PAI) in Africa, its prevalence, aetiology, genetics, presentation, diagnosis, and treatment and to determine the unmet needs in clinical care, education, and research.

MATERIALS AND METHODS

A narrative nonsystematic review of the literature was undertaken. We searched two online databases (PubMed and Google scholar) using the search terms "Addison's disease/PAI, primary adrenal insufficiency coupled with "Africa," "country names," and "genetic disorders." A total of 184 PAI records were reviewed. The exclusion of abstracts, conference proceedings, single case reports, and duplicate studies covering the same subject matter yielded 124 articles, of which 97 informed the final manuscript.

RESULTS

A wide range of aetiology of PAI was encountered, but their true prevalence is unknown. Aetiology varied with region and age of presentation as reflected by predominantly TB, HIV, and infective causes occurring in sub-Saharan Africa and more congenital forms described in North Africa associated with consanguinity. In Africa, the diagnostic criteria for PAI do not universally accord with conventional criteria, and there is a heavy reliance on clinical suspicion and biochemistry, including random cortisol of <400 nmol/L, rather than the tetracosactide test where stimulated cortisol <500-550 nmol/L confirms the diagnosis.

CONCLUSIONS

A high index of suspicion is warranted to diagnose PAI in resource-limited settings, especially where tetracosactide tests are not universally available.

Microalgal nanocellulose - opportunities for a circular bioeconomy

Over 3 billion years, photosynthetic algae have evolved complex uses for cellulose, the most abundant polymer worldwide. A major cell-wall component of lignocellulosic plants, seaweeds, microalgae, and bacteria, cellulose can be processed to nanocellulose, a promising nanomaterial with novel properties. The structural diversity of macro- and microalgal nanocelluloses opens opportunities to couple low-impact biomass production with novel, green-chemistry processing to yield valuable, sustainable nanomaterials for a multitude of applications ranging from novel wound dressings to organic solar cells. We review the origins of algal cellulose and the applications and uses of nanocellulose, and highlight the potential for microalgae as a nanocellulose source. Given the limited state of current knowledge, we identify research challenges and strategies to help to realise this potential.

Risk factors for COVID-19 hospitalisation and death in people living with diabetes: A virtual cohort study from the Western Cape Province, South Africa

BACKGROUND

COVID-19 outcomes and risk factors, including comorbidities and medication regimens, in people living with diabetes (PLWD) are poorly defined for low- and middle-income countries.

METHODS

The Provincial Health Data Centre (Western Cape, South Africa) is a health information exchange collating patient-level routine health data for approximately 4 million public sector health care seekers. Data from COVID-19 patients diagnosed between March and July 2020, including PLWD, were analysed to describe risk factors, including dispensed diabetes medications and comorbidities, and their association with COVID-19 outcomes in this population.

FINDINGS

There were 64,476 COVID-19 patients diagnosed. Of 9305 PLWD, 44.9% were hospitalised, 4.0% admitted to ICU, 0.6% received ventilation and 15.4% died. In contrast, proportions of COVID-19 patients without diabetes were: 12.2% hospitalised, 1.0% admitted, 0.1% ventilated and 4.6% died. PLWD were significantly more likely to be admitted (OR:3.73, 95 %CI: 3.53, 3.94) and to die (OR:3.01, 95 %CI: 2.76,3.28). Significant hospitalised risk factors included HIV infection, chronic kidney disease, current TB, male sex and increasing age. Significant risk factors for mortality were CKD, male sex, HIV infection, previous TB and increasing age. Pre-infection use of insulin was associated with a significant increased risk for hospitalisation (OR:1·39, 95 %CI:1·24,1·57) and mortality (OR1·49, 95 %CI:1·27; 1·74) and metformin was associated with a reduced risk for hospitalisation (OR:0·62,95 %CI:0·55, 0·71) and mortality (OR 0·77, 95 %CI:0·64; 0·92).

INTERPRETATION

Using routine health data from this large virtual cohort, we have described the association of infectious and noncommunicable comorbidities as well as pre-infection diabetes medications with COVID-19 outcomes in PLWD in the Western Cape, South Africa.

FUNDING

This research was funded in part, by the Wellcome Trust 203135/Z/16/Z, through support of NT. For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. The Wellcome Centre for Infectious Diseases Research in Africa is supported by core funding from the Wellcome Trust [203135/Z/16/Z]. NT receives funding from the CIDRI-Africa Wellcome Trust grant (203135/Z/16/Z), and NT and TT receive funding from the NIH H3ABioNET award (U24HG006941). NT receives funding from the UKRI/MRC (MC_PC_MR/T037733/1).

Addison's disease associated with hypokalemia: a case report

BACKGROUND

Primary adrenal insufficiency (Addison's disease) is a rare medical condition usually associated with hyperkalemia or normokalemia. We report a rare case of Addison's disease, coexisting with hypokalemia, requiring treatment.

CASE PRESENTATION

In this case, a 42-year-old man was admitted to the intensive care unit with a history of loss of consciousness and severe hypoglycemia. His blood tests showed metabolic acidosis, low concentrations of cortisol 6 nmol/L (normal 68-327 nmol/L), and high plasma adrenocorticotropic hormone 253 pmol/L (normal 1.6-13.9 pmol/L), and he was diagnosed with primary adrenal insufficiency. Surprisingly, his serum potassium was low, 2.3 mmol/L (normal 3.5-5.1 mmol/L), requiring replacement over the course of his admission. Computed tomography scan of the adrenal glands showed features suggestive of unilateral adrenal tuberculosis. Investigations confirmed renal tubulopathy. The patient responded favorably to cortisol replacement, but never required fludrocortisone.

CONCLUSIONS

Coexistence of hypokalemia with Addison's disease is unusual. We recommend investigation of the cause of hypokalemia in its own right, if it occurs with primary adrenal insufficiency.

Tiered healthcare in South Africa exposes deficiencies in management and more patients with infectious etiology of primary adrenal insufficiency

OBJECTIVE

We wished to determine the prevalence, etiology, presentation, and available management strategies for primary adrenal insufficiency (PAI) in South Africa (SA), hypothesizing a prevalence greater than the described 3.1 per million. There is great inequity in healthcare allocation, as two parallel healthcare systems exist, potentially modifying PAI patients' clinical profiles, private being better resourced than public healthcare.

METHODS

An online survey of physicians' experience relating to PAI.

RESULTS

The physicians were managing 811 patients, equal to a prevalence of 14.2 per million. Likely causes of PAI in public/ academic vs private settings included: AIDS-related [304 (44.8%) vs 5 (3.8%); p<0.001], tuberculosis [288 (42.5%) vs 8 (6.0%); p<0.001], autoimmune disease [50 (7.4%) vs 88 (66.2%); p<0.001], malignancy [27 (4.0%) vs 7 (5.3%); p = 0.500], genetic including adrenoleukodystrophy (ALD) [5 (0.7%) vs 16 (12.0%); p<0.001], respectively. Overall, more patients presented with nausea [101 (74.3%) and vomiting 89 (65.9%), than diarrhoea 76 (58.9%); p = 0.008 and 126 (15.5%) in adrenal crisis. Features suggestive of a crisis were hypoglycaemia [40 (78.4%) vs 42 (48.8%); p = 0.001], shock [36 (67.9%) vs 31(36.9%); p<0.001], and loss of consciousness [25 (52.1%) vs 27 (32.9%); p = 0.031]. Greater unavailability of antibody testing in the public vs. the private sector [32 (66.7%) vs 30 (32.1%); p = 0.001], [serum-ACTH 25 (52.1%) vs 16 (19.5%); p<0.001] and glucocorticoids were [26 (54.2%) vs 33 (40.2%); p = 0.015]. Many patients, 389(66.7%) were not using identification, indicating that they need steroids in an emergency.

CONCLUSION

A survey of South African physicians suggests a higher prevalence than previously reported. Patients presented with typical symptoms, and 15.5% presented in adrenal crisis. Significant disparities in the availability of physicians' expertise, diagnostic resources, and management options were noted in the public versus private settings. Greater awareness among health practitioners to timeously diagnose PAI is required to prevent a life-threatening outcome.

Significant barriers to diagnosis and management of adrenal insufficiency in Africa

BACKGROUND

The burden and management of primary adrenal insufficiency (PAI) in Africa have not been well documented. We aimed to identify specific disease characteristics, patient demographics, and patterns of clinical management in established PAI in Africa.

METHODS

An online survey of physicians' experience relating to PAI.

RESULTS

There were 1334 responses received, 589 were complete, and 332 respondents reported managing patients with hypoadrenalism. The described responses were related to a calculated pool of 5787 patients with hypoadrenalism (2746 females, 3041 males), of whom 2302 had PAI. The likely causes of PAI in Sub-Saharan Africa (SSA) vs the Middle East and North Africa (MENA) regions included autoimmune disease (20% vs 60.3%; P < 0.001), tuberculosis (34% vs 4.1%; P < 0.001), AIDS (29.8% vs 1%; P < 0.001), malignancy, and genetic conditions. Sixteen percent of AD patients (376/2302) presented in an adrenal crisis. Medical emergency identification was not used by 1233 (83.6%) SSA vs 330 (40.4%) MENA patients (P < 0.001), respectively. Relative non-availability of diagnostic tests across both regions included adrenal antibodies 63% vs 69.6% (P = 0.328), s-cortisol 49.4 % vs 26.7% (P = 0.004), s-ACTH 55.7% vs 53.3% (P = 0.217), and adrenal CT scans 52.4% vs 31.8% (P = 0.017) in the SSA and MENA region, respectively. Across the entire cohort, the overall hydrocortisone use and extrapolated proportion of synacthen use were 59.4% and 50.7%, respectively.

CONCLUSIONS

Through the perception and practice of healthcare professionals, we identified significant challenges in the diagnosis and management of PAI which may herald high mortality. Differences between regions may reflect the allocation of healthcare resources.

Detection and identification of dermatophyte fungi in clinical samples using a commercial multiplex tandem PCR assay

We evaluated the performance of a commercial multiplex tandem polymerase chain reaction (PCR) for detection of dermatophytes and other fungi in skin and nail specimens by (1) testing a range of fungal and bacterial reference cultures, (2) retrospectively testing a set of skin and nail specimens with known microscopy and culture results, and (3) prospectively testing skin and nail specimens in parallel to microscopy and culture. The AusDiagnostics Dermatophytes and Other Fungi assay accurately detected and identified a range of common dermatophytes to species, species complex or genus level, as well as Candida, Aspergillus and Scopulariopsis spp. It was unable to detect uncommon dermatophytes such as Nannizzia fulva (previously Microsporum fulvum), and Paraphyton cookei (previously Microsporum cookei). PCR identified a dermatophyte in 25.9% of prospective specimens which were culture negative. Sensitivity, specificity, positive predictive value, and negative predictive value were highest where microscopy and PCR results were combined, versus microscopy and culture combined, which highlights the significant contribution of microscopy in the diagnostic pathway. This assay has the potential to reduce the workload and results turnaround time associated with culturing and identification of dermatophytes, although microscopy remains important.

Nodal disease predicts recurrence whereas other traditional factors affect survival in a cohort of South African patients with differentiated thyroid carcinoma

Background and aim

Information on patients with differentiated thyroid carcinoma in South Africa is limited. The objective of this study was to review demographics and tumour characteristics in a cohort of patients with differentiated thyroid carcinoma, presenting to Groote Schuur Hospital and evaluate risk factors for recurrence and survival.

Patients and methodology

Retrospective demographic and clinical data were collected on all patients referred between January 2003 and December 2013. Prognostic factors for recurrence free survival and cancer specific survival were assessed using univariate and multivariate analyses.

Results

The total number of patients was 231.The median age at presentation was 44 years and 82% were female patients. The pathological sub-types were papillary (60.6%), follicular (38.9%) and poorly differentiated (0.5%). Total thyroidectomy was performed in 191 patients and 30 patients required neck dissections. A total of 171 (74%) patients received ¹³¹Iodine. The recurrence free and cause specific survival rates at 10 years were 83 and 91%, respectively. Nodal disease at presentation was the only significant risk factor for recurrence (p <  0.001) on multivariate analysis. Significant risk factors for cause specific mortality were age ≥ 45 years (p = 0.006), follicular pathology (p = 0.004), extra-thyroid extension (p = 0.013) and residual tumour (p = 0.004).

Conclusions

Consistent with international trends, patients with differentiated thyroid carcinoma treated at Groote Schuur Hospital had a favourable prognosis. The known risk factors associated with recurrence and survival in this South African cohort were consistent with those reported in developed countries.

Effect of prednisolone on inflammatory markers in pericardial tuberculosis: A pilot study

BACKGROUND

Pericardial disorders are a common cause of heart disease, and the most common cause of pericarditis in developing countries is tuberculous (TB) pericarditis. It has been shown that prednisolone added to standard anti-TB therapy leads to a lower rate of constrictive pericarditis. We conducted a pilot study to evaluate the effect of adjunctive prednisolone treatment on the concentration of inflammatory markers in pericardial tuberculosis, in order to inform immunological mechanisms at the disease site.

METHODS

Pericardial fluid, plasma and saliva samples were collected from fourteen patients with pericardial tuberculosis, at multiple time points. Inflammatory markers were measured using multiplex luminex analysis and ELISA.

RESULTS

In samples from 14 patients we confirmed a strongly compartmentalized immune response at the disease site and found that prednisolone significantly reduced IL-6 concentrations in plasma by 8 hours of treatment, IL-1beta concentrations in saliva, as well as IL-8 concentrations in both pericardial fluid and saliva by 24 hours.

CONCLUSION

Monitoring the early effect of adjunctive immunotherapy in plasma or saliva is a possibility in pericarditis.

Salivary Cortisol and Cortisone do not Appear to be Useful Biomarkers for Monitoring Hydrocortisone Replacement in Addison's Disease

Salivary cortisol has been used to monitor hydrocortisone replacement in patients with Addison's disease (AD). Since salivary cortisol is metabolised to salivary cortisone, it may be an adjunctive analyte to assess adequacy of hydrocortisone replacement in patients with AD. We aimed to characterise the exposure of salivary cortisol and cortisone in patients and healthy controls. We measured salivary cortisol and cortisone by liquid chromatography-tandem mass spectrometry and constructed a day curve (08:00 until 24:00 h) with 16 time points in 25 AD patients taking their usual hydrocortisone dose and in 26 healthy controls. The median (interquartile range) area under the curve (AUC) for cortisol was not different for patients, compared with controls [55.63 (32.91-151.07) nmol*min*l^-1 vs. 37.49 (27.41-52.00) nmol*min*l^-1; p=0.098, respectively], whereas the peak cortisol C_max was higher in patients [32.61 (5.75-146.19) nmol/l vs. 8.96 (6.96-12.23) nmol/l; p=0.013], compared with controls. The AUC for cortisone [23.65 (6.10-54.76) nmol*min*l^-1 vs. 227.73 (200.10-280.52) nmol*min*l^-1; p≤ 0.001, respectively], and peak cortisone C_max was lower in patients than in controls [11.11 (2.91-35.85) nmol/l vs. 33.12 (25.97-39.95) nmol/l; p=0.002]. The AUC for salivary cortisol and salivary cortisone were not correlated with any measures of hydrocortisone dose. The time-course and AUC of salivary cortisol were similar between Addison's patients and healthy controls. Patients had substantially lower salivary cortisone AUC, compared to healthy controls. Salivary cortisol AUC and pharmacokinetics were not related to hydrocortisone dose and thus are not likely useful markers for the adequacy of hydrocortisone replacement.

Anti-Retroviral Therapy Increases the Prevalence of Dyslipidemia in South African HIV-Infected Patients

PURPOSE

Data on the prevalence of dyslipidaemia and associated risk factors in HIV-infected patients from sub-Saharan Africa is sparse. We performed a cross-sectional analysis in a cohort of HIV-infected South African adults.

METHODS

We studied HIV-infected patients who were either antiretroviral therapy (ART)-naive or receiving non-nucleoside reverse transcriptase inhibitor (NNRTI)-based or protease inhibitor (PI)-based ART. Evaluation included fasting lipograms, oral glucose tolerance tests and clinical anthropometry. Dyslipidemia was defined using the NCEP ATPIII guidelines.

RESULTS

The median age of the participants was 34 years (range 19-68 years) and 78% were women. The prevalence of dyslipidemia in 406 ART-naive and 551 participants on ART was 90.0% and 85%, respectively. Low HDL-cholesterol (HDLC) was the most common abnormality [290/406 (71%) ART-naïve and 237/551 (43%) ART- participants]. Participants on ART had higher triglycerides (TG), total cholesterol (TC), LDL-cholesterol (LDLC) and HDLC than the ART-naïve group. Severe dyslipidaemia, (LDLC> 4.9 mmol/L or TG >5.0 mmol/L) was present in <5% of participants. In multivariate analyses there were complex associations between age, gender, type and duration of ART and body composition and LDLC, HDLC and TG, which differed between ART-naïve and ART-participants.

CONCLUSION

Participants on ART had higher TG, TC, LDLC and HDLC than those who were ART-naïve but severe lipid abnormalities requiring evaluation and treatment were uncommon.

Poor Penetration of Antibiotics Into Pericardium in Pericardial Tuberculosis

Pericardial tuberculosis (TB) is associated with high therapy failure and high mortality rates. Antibiotics have to penetrate to site of infection at sufficient non-protein bound concentrations, and then enter bacteria to inhibit intracellular biochemical processes. The antibiotic concentrations achieved in pericardial fluid in TB pericarditis have never been measured before. We recruited two cohorts of patients with TB pericarditis, and left a pigtail catheter in-situ for serial drug concentration measurements over 24 h. Altogether, 704 drug concentrations were comodeled for pharmacokinetic analyses. The drug concentrations achieved in pericardial fluid were compared to the minimum inhibitory concentrations (MICs) of clinical Mycobacterium tuberculosis isolates. The total rifampicin concentration pericardial-to-serum ratios in 16 paired samples were 0.19 ± 0.33. The protein concentrations of the pericardial fluid in TB pericarditis were observed to be as high as in plasma. The non-protein bound rifampicin concentrations in pericardial fluid were 4-fold lower than rifampicin MICs in the pilot study, and the peak concentration was 0.125 versus 0.208 mg/L in the second (p = 0.001). The rifampicin clearance from pericardial fluid was 9.45 L/h versus 7.82 L/h in plasma (p = 0.002). Ethambutol peak concentrations had a pericardial-to-plasma ratio of 0.55 ± 0.22; free ethambutol peak concentrations were 2.30-lower than MICs (p < 0·001). The pericardial fluid pH was 7.34. The median pyrazinamide peak concentrations were 42.93 mg/L versus a median MIC of 800 mg/L at pH 7.34 (p < 0.0001). There was no significant difference between isoniazid pericardial fluid and plasma concentrations, and isoniazid peak concentrations were above MIC. This is the first study to measure anti-TB drug concentrations, pH and protein in the pericardial TB fluid. Pericardial concentrations of the key sterilizing drugs for TB were below MIC, which could contribute to poor outcomes. A new regimen that overcomes these limitations might need to be crafted.

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The amounts of antibiotics such as rifampicin, ethambutol, pyrazinamide and isoniazid used to treat TB pericarditis that enter pericardial fluid have up to now been unknown

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The study found that the pH in pericardial fluid was alkaline, which would mean that pyrazinamide effect would be compromised.

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The protein content in pericardial fluid was high, which would lead to low non-protein bound rifampicin and ethambutol concentrations

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The concentrations of rifampicin, ethambutol and pyrazinamide in pericardial were dramatically low and below the MICs of Mycobacterium tuberculosis

Poor quality of life, depressed mood, and memory impairment may be mediated by sleep disruption in patients with Addison's disease

Standard replacement therapy for Addison's disease (AD) does not restore a normal circadian rhythm. In fact, hydrocortisone replacement in AD patients likely induces disrupted sleep. Given that healthy sleep plays an important role in improving quality of life, optimizing cognition, and ensuring affect regulation, the aim of this study was to investigate whether poor quality of life, mood alterations, and memory complaints reported by AD patients are associated with their disrupted sleep patterns. Sixty patients with AD and 60 matched healthy controls completed a battery of self-report questionnaires assessing perceived physical and mental health (Short-Form 36), mood (Beck Depression Inventory-II), sleep quality (Pittsburgh Sleep Quality Index), and cognition (Cognitive Failures Questionnaire). A latent variable model revealed that although AD had a significant direct effect on quality of life, the indirect effect of sleep was significantly greater. Furthermore, although AD had no direct effect on cognitive functioning, the indirect effect of sleep was significant. The overall model showed a good fit (comparative fit index = 0.91, root mean square of approximation = 0.09, and standardized root mean square residual = 0.05). Our findings suggest that disrupted sleep, and not the disease per se, may induce poor quality of life, memory impairment, and affect dysregulation in patients with AD. We think that improving sleep architecture may improve cognitive, affective, and physical functioning.

Sulphur responsiveness of the Chlamydomonas reinhardtii LHCBM9 promoter

A 44-base-pair region in the Chlamydomonas reinhardtii LHCBM9 promoter is essential for sulphur responsiveness. The photosynthetic light-harvesting complex (LHC) proteins play essential roles both in light capture, the first step of photosynthesis, and in photoprotective mechanisms. In contrast to the other LHC proteins and the majority of photosynthesis proteins, the Chlamydomonas reinhardtii photosystem II-associated LHC protein, LHCBM9, was recently reported to be up-regulated under sulphur deprivation conditions, which also induce hydrogen production. Here, we examined the sulphur responsiveness of the LHCBM9 gene at the transcriptional level, through promoter deletion analysis. The LHCBM9 promoter was found to be responsive to sulphur deprivation, with a 44-base-pair region between nucleotide positions -136 and -180 relative to the translation start site identified as essential for this response. Anaerobiosis was found to enhance promoter activity under sulphur deprivation conditions, however, alone was unable to induce promoter activity. The study of LHCBM9 is of biological and biotechnological importance, as its expression is linked to photobiological hydrogen production, theoretically the most efficient process for biofuel production, while the simplicity of using an S-deprivation trigger enables the development of a novel C. reinhardtii-inducible promoter system based on LHCBM9.

Embryological and molecular development of the adrenal glands

In this mini review, the embryological and functional development of the adrenal glands is presented from a molecular perspective. While acknowledging that this is a highly complex series of events, the processes are described in simple and broad strokes in a single text for the reader who is interested in this field but is not an active researcher. The origin of the adrenal glands is in the mesodermal ridge as early as the fourth week of gestation. Between the eighth and ninth weeks of gestation, the adrenal glands are encapsulated and this results in the presence of a distinct organ. There have been great strides in deciphering the very complicated molecular aspects of adrenal gland development in which multiple transcription factors have been identified, directing the adrenogonadal primordium into the adrenal cortex, kidney, or bipotential gonad. Adrenocorticotrophic hormone is critical for early development of the hypothalamic-pituitary adrenal axis. Several mutations in transcription factors, responsible for normal adrenal gland development have been found to induce the familial syndrome of congenital adrenal hypoplasia or neoplasia.

Male and female hypogonadism are highly prevalent in South Africans with Addison's disease

Hypogonadism may complicate Addison's disease (primary hypoadrenalism), but prevalence and metabolic sequelae of hypogonadism in Addison's disease are poorly described. We recruited patients from the South African Addison's disease national registry who received stable replacement doses of hydrocortisone and had no acute illness. Male biochemical testosterone deficiency was defined as an early morning basal testosterone<9.9 nmol/l and premature ovarian failure (POF) when menopause occurred before 40 years of age. Cardiometabolic risk variables were measured in males only. Male hypogonadism prevalence was 33% (14/42), and 10 patients had newly diagnosed hypogonadism. Two untreated patients had elevated FSH or LH (>10 or 12 IU/l). Testosterone deficiency did not correlate with age, disease duration or hydrocortisone dose. Untreated male hypogonadal subjects had a higher (mean ± standard deviation) BMI compared to eugonadal subjects 29.2 ± 4.9 kg/m(2) vs. 24.7 ± 3.4 kg/m(2) (p=0.01) and a higher median (interquartile range) high-sensitive-CRP 6.4 (2.5-14.0) mg/l vs. 1.45 (0.6-2.8) mg/l (p=0.002). There were no differences between the 2 groups in lipids, lipoproteins and fasting glucose. The median (interquartile range) DHEAS was lower in the hypogonadal 0.31 (0.27-0.37) μmol/l, compared with the eugonadal group 0.75 (0.50-1.51) μmol/l (p=0.005). POF was documented in 11% of female patients. Male testosterone deficiency was highly prevalent in this cohort and was primarily due to secondary hypogonadism. Only BMI and hs-CRP were increased in untreated male hypogonadal subjects. Male and female hypogonadism appears to be a common complication of Addison's disease and may contribute to its morbidity.

Episodic memory impairment in Addison's disease: results from a telephonic cognitive assessment

Patients with Addison's disease frequently self-report memory and attention difficulties, even when on standard replacement therapy. However, few published studies examine, using objective measures and assessing across multiple domains, the cognitive functioning of Addison's disease patients relative to healthy controls. The primary aim of this study was to investigate whether the previously reported subjective cognitive deficits in Addison's disease are confirmed by objective measures. Conducting comprehensive neuropsychological assessments of patients with relatively rare clinical disorders, such as Addison's disease, is challenging because access to those patients is often limited, and because their medical condition might prevent extended testing sessions. Brief telephonic cognitive assessments are a useful tool in such circumstances. Hence, we administered the Brief Test of Adult Cognition by Telephone to 27 Addison's disease patients and 27 matched healthy controls. The instrument provides objective assessment of episodic memory, working memory, executive functioning, reasoning, and speed of processing. Statistical analyses confirmed that, as expected, patients performed significantly more poorly than controls on the episodic memory subtest. There were, however, no significant between-group differences on the attention, executive functioning, reasoning, and speed of processing subtests. Furthermore, patients with a longer duration of illness performed more poorly across all domains of cognition. We conclude that, for Addison's disease patients, previously reported subjective cognitive deficits are matched by objective impairment, but only in the domain of episodic memory. Future research might investigate (a) whether these memory deficits are material-specific (i.e., whether non-verbal memory is also affected), and (b) the neurobiological mechanisms underlying these deficits.

Flow cytometry pulse width data enables rapid and sensitive estimation of biomass dry weight in the microalgae Chlamydomonas reinhardtii and Chlorella vulgaris

Dry weight biomass is an important parameter in algaculture. Direct measurement requires weighing milligram quantities of dried biomass, which is problematic for small volume systems containing few cells, such as laboratory studies and high throughput assays in microwell plates. In these cases indirect methods must be used, inducing measurement artefacts which vary in severity with the cell type and conditions employed. Here, we utilise flow cytometry pulse width data for the estimation of cell density and biomass, using Chlorella vulgaris and Chlamydomonas reinhardtii as model algae and compare it to optical density methods. Measurement of cell concentration by flow cytometry was shown to be more sensitive than optical density at 750 nm (OD750) for monitoring culture growth. However, neither cell concentration nor optical density correlates well to biomass when growth conditions vary. Compared to the growth of C. vulgaris in TAP (tris-acetate-phosphate) medium, cells grown in TAP + glucose displayed a slowed cell division rate and a 2-fold increased dry biomass accumulation compared to growth without glucose. This was accompanied by increased cellular volume. Laser scattering characteristics during flow cytometry were used to estimate cell diameters and it was shown that an empirical but nonlinear relationship could be shown between flow cytometric pulse width and dry weight biomass per cell. This relationship could be linearised by the use of hypertonic conditions (1 M NaCl) to dehydrate the cells, as shown by density gradient centrifugation. Flow cytometry for biomass estimation is easy to perform, sensitive and offers more comprehensive information than optical density measurements. In addition, periodic flow cytometry measurements can be used to calibrate OD750 measurements for both convenience and accuracy. This approach is particularly useful for small samples and where cellular characteristics, especially cell size, are expected to vary during growth.

Gateway-assisted vector construction to facilitate expression of foreign proteins in the chloroplast of single celled algae

With a rising world population, demand will increase for food, energy and high value products. Renewable production systems, including photosynthetic microalgal biotechnologies, can produce biomass for foods, fuels and chemical feedstocks and in parallel allow the production of high value protein products, including recombinant proteins. Such high value recombinant proteins offer important economic benefits during startup of industrial scale algal biomass and biofuel production systems, but the limited markets for individual recombinant proteins will require a high throughput pipeline for cloning and expression in microalgae, which is currently lacking, since genetic engineering of microalgae is currently complex and laborious. We have introduced the recombination based Gateway® system into the construction process of chloroplast transformation vectors for microalgae. This simplifies the vector construction and allows easy, fast and flexible vector design for the high efficiency protein production in microalgae, a key step in developing such expression pipelines.

Impact of procedural steps and cryopreservation agents in the cryopreservation of chlorophyte microalgae

The maintenance of traditional microalgae collections based on liquid and solid media is labour intensive, costly and subject to contamination and genetic drift. Cryopreservation is therefore the method of choice for the maintenance of microalgae culture collections, but success is limited for many species. Although the mechanisms underlying cryopreservation are understood in general, many technical variations are present in the literature and the impact of these are not always elaborated. This study describes two-step cryopreservation processes in which 3 microalgae strains representing different cell sizes were subjected to various experimental approaches to cryopreservation, the aim being to investigate mechanistic factors affecting cell viability. Sucrose and dimethyl sulfoxide (DMSO) were used as cryoprotectants. They were found to have a synergistic effect in the recovery of cryopreserved samples of many algal strains, with 6.5% being the optimum DMSO concentration. The effect of sucrose was shown to be due to improved cell survival and recovery after thawing by comparing the effect of sucrose on cell viability before or after cryopreservation. Additional factors with a beneficial effect on recovery were the elimination of centrifugation steps (minimizing cell damage), the reduction of cell concentration (which is proposed to reduce the generation of toxic cell wall components) and the use of low light levels during the recovery phase (proposed to reduce photooxidative damage). The use of the best conditions for each of these variables yielded an improved protocol which allowed the recovery and subsequent improved culture viability of a further 16 randomly chosen microalgae strains. These isolates included species from Chlorellaceae, Palmellaceae, Tetrasporaceae, Palmellopsis, Scenedesmaceae and Chlamydomonadaceae that differed greatly in cell diameter (3-50 µm), a variable that can affect cryopreservation success. The collective improvement of each of these parameters yielded a cryopreservation protocol that can be applied to a broad range of microalgae.

Increased cardiovascular risk in South African patients with Addison's disease

Patients with Addison's disease (AD) are believed to be at risk for cardiovascular disease (CVD). South Africa, like the rest of the developing world is experiencing an increase in CVD and patients with AD may be at double the risk of their peers. We wished to explore AD patients' CVD risk factors. A cross-sectional nationwide study in South Africa of patients with AD was conducted. A cohort of 147 patients with AD and 147 healthy control subjects were matched by age, gender, ethnicity, and BMI as far as was possible. Lipoproteins and highly-sensitive C-reactive-protein (hs-CRP) were the main outcome measures. AD patients had significantly higher triglycerides; (p=0.001), lower HDLC (p<0.001), higher hs-CRP (p<0.001), and more small dense LDL; (p=0.002) than controls. Nonesterified fatty acids were lower in patients (p<0.001). Approximately 65% [95% confidence interval (CI 55.6-72.4%)] had hypercholesterolaemia, 75% (CI 64.8-81.2%) had low HDLC, and 75% (CI 68.0-84.1%) had a higher LDLC. Thirteen percent of AD patients had diabetes mellitus, but none of the risk factors differed from the nondiabetics. Only HDLC correlated positively with daily hydrocortisone dose (r=0.32; p=0.005). In conclusion dyslipidaemia is common in South African AD patients; CVD risk assessment and intervention are probably warranted in the management of these patients.

RNAi knock-down of LHCBM1, 2 and 3 increases photosynthetic H2 production efficiency of the green alga Chlamydomonas reinhardtii

Single cell green algae (microalgae) are rapidly emerging as a platform for the production of sustainable fuels. Solar-driven H₂ production from H₂O theoretically provides the highest-efficiency route to fuel production in microalgae. This is because the H₂-producing hydrogenase (HYDA) is directly coupled to the photosynthetic electron transport chain, thereby eliminating downstream energetic losses associated with the synthesis of carbohydrate and oils (feedstocks for methane, ethanol and oil-based fuels). Here we report the simultaneous knock-down of three light-harvesting complex proteins (LHCMB1, 2 and 3) in the high H₂-producing Chlamydomonas reinhardtii mutant Stm6Glc4 using an RNAi triple knock-down strategy. The resultant Stm6Glc4L01 mutant exhibited a light green phenotype, reduced expression of LHCBM1 (20.6% ±0.27%), LHCBM2 (81.2% ±0.037%) and LHCBM3 (41.4% ±0.05%) compared to 100% control levels, and improved light to H₂ (180%) and biomass (165%) conversion efficiencies. The improved H₂ production efficiency was achieved at increased solar flux densities (450 instead of ∼100 µE m⁻² s⁻¹) and high cell densities which are best suited for microalgae production as light is ideally the limiting factor. Our data suggests that the overall improved photon-to-H₂ conversion efficiency is due to: 1) reduced loss of absorbed energy by non-photochemical quenching (fluorescence and heat losses) near the photobioreactor surface; 2) improved light distribution in the reactor; 3) reduced photoinhibition; 4) early onset of HYDA expression and 5) reduction of O₂-induced inhibition of HYDA. The Stm6Glc4L01 phenotype therefore provides important insights for the development of high-efficiency photobiological H₂ production systems.

Investigation of glucocorticoid receptor polymorphisms in relation to metabolic parameters in Addison's disease

BACKGROUND

Uncertainty exists whether glucocorticoid receptor (GCR) polymorphisms play a role in steroid-related side effects in Addison's disease (AD) patients on hydrocortisone. The polymorphisms Bcll and N363S appear to increase sensitivity to cortisol, while the ER22/23EK polymorphism has been associated with resistance to cortisol.

METHOD

One hundred and forty seven AD patients, and gender, and ethnicity-matched controls were recruited in South Africa. Three polymorphisms in the GCR were studied, using PCR followed by restriction fragment length analysis. Associations with BMI, lipids, glucose and inflammatory markers were investigated.

RESULTS

In both patients and controls, the Bcll polymorphism occurred more frequently in whites than in other ethnic groups studied but was not associated with any of the metabolic parameters tested. The ER22/23EK polymorphism was associated with an increased BMI in both patients (29.4 vs 24.7  kg/m²) and control subjects (26.3 vs 24.2  kg/m²). The ER22/23EK polymorphism was also associated with lower LDL cholesterol in control subjects (3.46 vs 3.93  mmol/l) and in patients (3.52 vs 4.10  mmol/l). N363S was associated with increased BMI in controls 29.9  kg/m² vs wild type 24.8  kg/m². Median hydrocortisone doses were greater in patients heterozygous for either ER22/23EK 30.0  mg or N363S 25.0  mg polymorphisms than in wild type patients 20.0  mg (both comparisons).

CONCLUSION

Alterations in lipids, BMI and hydrocortisone dose were associated with two polymorphisms. Further larger studies are warranted to corroborate these findings.

Salivary cortisol day curves in Addison's disease in patients on hydrocortisone replacement

Using salivary cortisol (SC) measurements, cortisol exposure in Addison's disease patients on hydrocortisone replacement was determined and compared with healthy controls. Cortisol pharmacokinetics was assessed in 31 patients with Addison's disease on replacement hydrocortisone doses (median daily dose 20 mg; range 5-50 mg) and 30 healthy control subjects. Saliva samples (n=16) were collected between 08:00 and 00:00 h in 1 day, using a passive drool technique. Cortisol exposure was evaluated by noncompartmental approach. In the patients, cortisol exposure was significantly higher than in controls: median inter-quartile range (IQR) peak cortisol (C(max)) 174.5 (59.3-837.0) vs. 6.50 (4.7-19.3) nmol/l, p=0.0001; area under the curve (AUC) 390.1 (177.1-928.9) vs. 21.4 (14.6-28.4) minutes*nmol/l, p=0.0001, trough cortisol level (C(min)) 0.49 (0.49-0.96) vs. 0.49 (0.49-0.49) nmol/l, p=0.02, occurring at 480.0 (0.1-660.0) vs. 405.0 (180.0-570.0) min, p=0.56. First peak cortisol was 174.5 (53.0-754.7) vs. 6.27 (3.90-8.47) nmol/l, p=0.0001 and second peak cortisol 18.90 (5.22-76.9) vs. 3.12 (1.76-4.79) nmol/l, p=0.0001. The time to first peak cortisol differed between the 2 groups, 30 (30-75) vs. 0.1 (0.1-30) minutes; p=0.0001. At doses studied, hydrocortisone replacement therapy results in cortisol pharmacokinetics being markedly different from endogenous cortisol profiles in healthy control subjects. Addison's disease patients had significantly higher SC levels compared to healthy control subjects.

Selection, breeding and engineering of microalgae for bioenergy and biofuel production

Microalgal production technologies are seen as increasingly attractive for bioenergy production to improve fuel security and reduce CO(2) emissions. Photosynthetically derived fuels are a renewable, potentially carbon-neutral and scalable alternative reserve. Microalgae have particular promise because they can be produced on non-arable land and utilize saline and wastewater streams. Furthermore, emerging microalgal technologies can be used to produce a range of products such as biofuels, protein-rich animal feeds, chemical feedstocks (e.g. bioplastic precursors) and higher-value products. This review focuses on the selection, breeding and engineering of microalgae for improved biomass and biofuel conversion efficiencies.

Proteomic and electron microscopy survey of large assemblies in macrophage cytoplasm

Many cellular processes are carried out by large macromolecular assemblies. We systematically analyzed large macromolecular assemblies in the cytoplasm of mouse macrophages (RAW264.7 cell line), cells with crucial roles in immunity and inflammation. Fractionation of the cytoplasmic fraction was performed using sucrose density gradient centrifugation, and individual fractions were subjected in parallel to (i) identification of constituent proteins by mass spectrometry and (ii) structural visualization by electron microscopy. Macromolecular assemblies present in the fractions were analyzed by integrating available data using bioinformatic approaches. We identified 368 unique proteins in our sample. Among these are components of some well-characterized assemblies involved in diverse cellular processes and structures including translation, proteolysis, protein folding, metabolism, and the cytoskeleton, as well as less characterized proteins that may correspond to additional components of known assemblies or other homo- or hetero-oligomeric structures. Single-particle analysis of electron micrographs of negatively stained samples allowed the identification of clearly distinguishable two-dimensional projections of discrete protein assemblies. Among these, we can identify small ribosomal subunits and preribosomal particles, the 26S proteasome complex and small ringlike structures resembling the molecular chaperone complexes. In addition, a broad range of discrete and different complexes were seen at size ranges between 11 to 38 nm in diameter. Our procedure selects the assemblies on the basis of abundance and ease of isolation, and therefore provides an immediately useful starting point for further study of structure and function of large assemblies. Our results will also contribute toward building a molecular cell atlas.

B cells do not take up bacterial DNA: an essential role for antigen in exposure of DNA to toll-like receptor-9

Murine dendritic cells (DC) and macrophages respond to bacterial CpG DNA through toll-like receptor 9 (TLR9). Although it is frequently assumed that bacterial DNA is a direct stimulus for B cells, published work does not reliably show responses of purified B cells. Here we show that purified splenic B cells did not respond to Escherichia coli DNA with induction of CD86, despite readily responding to single-stranded (ss) phosphodiester CpG oligodeoxynucleotides (ODN). This was due to a combination of weak responses to both long and double-stranded (ds) DNA. B-cell DNA uptake was greatly reduced with increasing DNA length. This contrasts with macrophages where DNA uptake and subsequent responses were enhanced with increasing DNA length. However, when DNA was physically linked to hen egg lysozyme (HEL), HEL-specific B cells showed efficient uptake of DNA, and limited proliferation in response to the HEL-DNA complex. We propose that, in the absence of other signals, B cells have poor uptake and responses to long dsDNA to prevent polyclonal activation. Conversely, when DNA is physically linked to a B-cell receptor (BCR) ligand, its uptake is increased, allowing TLR9-dependent B-cell activation in an antigen-specific manner. We could not generate fragments of E. coli DNA by limited DNaseI digestion that could mimic the stimulatory effect of ss CpG ODN on naïve B cells. We suggest that the frequently studied polyclonal B-cell responses to CpG ODN are relevant to therapeutic applications of phosphorothioate-modified CpG-containing ODN, but not to natural responses to foreign or host dsDNA.

Future prospects of microalgal biofuel production systems

Climate change mitigation, economic growth and stability, and the ongoing depletion of oil reserves are all major drivers for the development of economically rational, renewable energy technology platforms. Microalgae have re-emerged as a popular feedstock for the production of biofuels and other more valuable products. Even though integrated microalgal production systems have some clear advantages and present a promising alternative to highly controversial first generation biofuel systems, the associated hype has often exceeded the boundaries of reality. With a growing number of recent analyses demonstrating that despite the hype, these systems are conceptually sound and potentially sustainable given the available inputs, we review the research areas that are key to attaining economic reality and the future development of the industry.

A comparison of two PCR-based typing methods with pulsed-field gel electrophoresis in Salmonella enterica serovar Enteritidis

Two novel molecular typing methods, multiple-locus variable-number tandem repeats (VNTR) analysis (MLVA) and multiple amplification of phage loci typing (MAPLT), were compared with pulsed-field gel electrophoresis (PFGE) for the discrimination of 128 Salmonella enterica serovar Enteritidis (S. Enteritidis) isolates. Selected epidemiologically unrelated isolates represented a cross-section of phage types routinely isolated in Australia and included 28 isolates that could not be assigned a phage type. Targeting 5 previously described loci, MLVA generated 61 different profiles with a Simpson index of diversity of DI=0.968. MLVA locus STTR-5 proved to be the most diverse with 11 different alleles detected with a Nei's diversity index value of D=0.769. Using 8 MAPLT primers previously developed for S. Typhimurium produced 36 different profiles with a DI value of 0.948. By contrast, PFGE only generated 13 different pulsed-field patterns, DI=0.873. Within each phage type there was variation in the extent to which either molecular method was able to discriminate the S. Enteritidis isolates. MAPLT provided more discrimination in terms of the number of profiles and DI value for phage type 1 and the untypable strains while MLVA was more discriminatory for phage types 14var and 26. There was a general lack of concordance of either molecular assay to phage type. These results suggest that both MAPLT and MLVA have excellent potential as tools for epidemiological studies of S. Enteritidis.

HIN-200 proteins regulate caspase activation in response to foreign cytoplasmic DNA

The mammalian innate immune system is activated by foreign nucleic acids. Detection of double-stranded DNA (dsDNA) in the cytoplasm triggers characteristic antiviral responses and macrophage cell death. Cytoplasmic dsDNA rapidly activated caspase 3 and caspase 1 in bone marrow-derived macrophages. We identified the HIN-200 family member and candidate lupus susceptibility factor, p202, as a dsDNA binding protein that bound stably and rapidly to transfected DNA. Knockdown studies showed p202 to be an inhibitor of DNA-induced caspase activation. Conversely, the related pyrin domain-containing HIN-200 factor, AIM2 (p210), was required for caspase activation by cytoplasmic dsDNA. This work indicates that HIN-200 proteins can act as pattern recognition receptors mediating responses to cytoplasmic dsDNA.

Microalgal biofuel systems: Climate change, fuel supply and economic opportunities for sustainable development

The development of carbon neutral fuels for the future is one of the most urgent challenges facing our society for three reasons ? to minimise the effects of climate change, to protect against fuel price shocks and to provide a secure basis for economic growth.

The use of MAPLT and MLVA analyses of phenotypically closely related isolates of Salmonella enterica serovar Typhimurium

The resolving power of multiple-locus variable-number tandem repeat analysis (MLVA) was undertaken on 78 phenotypically closely related isolates of Salmonella enterica serovar Typhimurium that were previously analysed with multiple amplification of phage locus typing (MAPLT) and pulsed-field gel electrophoresis (PFGE). Isolates were tested with 10 primer sets targeting tandem repeat loci in the S. Typhimurium genome. A new primer set targeting the SB21(ST64B) locus was also assessed for MAPLT analysis. Both methods produced similar levels of discrimination between 41 non-DT 126 isolates while MLVA proved superior in separating the DT 126 isolates. Results showed that two loci, STTR5 and STTR6, provided the most variation in tandem repeat numbers between the 78 S. Typhimurium isolates with 11 alleles detected for each locus. Some isolates did not produce amplified product with PCR for various loci, providing another level for discrimination. The remaining MLVA loci provided less allelic variation, with 4 loci failing to provide any discrimination. There were a number of isolates that were shown to be unique by one method but were clustered by the other method. Combining the most variable regions of both MAPLT and MLVA into one assay may provide significant resolution of isolates with the minimal number of primers utilised.

A comparison of three molecular typing methods for the discrimination of Salmonella enterica serovar Infantis

Seventy-six epidemiologically unrelated Salmonella enterica serovar Infantis (S. Infantis) isolates were typed by pulsed-field gel electrophoresis (PFGE), multiple amplification of phage loci typing (MAPLT) and multiple-locus variable-number tandem-repeat analysis (MLVA). PFGE, using the restriction endonuclease XbaI, generated 23 different profiles for the 76 isolates (DI=0.848). MAPLT was undertaken using a combination of 11 primer sets based on bacteriophage sequences and generated 28 different profiles (DI=0.938). By contrast, MLVA only produced nine profiles (DI=0.668) with 13 different primer sets, including the five primer sets routinely used for S. Typhimurium typing. Reducing the number of MAPLT primer sets to four still provided a diversity index of 0.838. All three typing methods revealed two distinct lineages of S. Infantis, with most isolates demonstrating genetic traits of either lineage but not both. The results demonstrate that MAPLT can potentially provide greater discrimination and separation of S. Infantis isolates than both PFGE and MLVA. Furthermore, MAPLT data can be generated much more rapidly and with reduced labour input than PFGE and without the need for expensive PFGE electrophoresis equipment, nor does it require capillary sequencing of PCR fragments to accurately determine PCR fragment lengths as is the case with MLVA.