A Drug Repurposing Approach Reveals Targetable Epigenetic Pathways in Plasmodium vivax Hypnozoites.

Radical cure of Plasmodium vivax malaria must include elimination of quiescent 'hypnozoite' forms in the liver; however, the only FDA-approved treatments are contraindicated in many vulnerable populations. To identify new drugs and drug targets for hypnozoites, we screened the Repurposing, Focused Rescue, and Accelerated Medchem (ReFRAME) library and a collection of epigenetic inhibitors against P. vivax liver stages. From both libraries, we identified inhibitors targeting epigenetics pathways as selectively active against P. vivax and P. cynomolgi hypnozoites. These include DNA methyltransferase (DNMT) inhibitors as well as several inhibitors targeting histone post-translational modifications. Immunofluorescence staining of Plasmodium liver forms showed strong nuclear 5-methylcystosine signal, indicating liver stage parasite DNA is methylated. Using bisulfite sequencing, we mapped genomic DNA methylation in sporozoites, revealing DNA methylation signals in most coding genes. We also demonstrated that methylation level in proximal promoter regions as well as in the first exon of the genes may affect, at least partially, gene expression in P. vivax. The importance of selective inhibitors targeting epigenetic features on hypnozoites was validated using MMV019721, an acetyl-CoA synthetase inhibitor that affects histone acetylation and was previously reported as active against P. falciparum blood stages. In summary, our data indicate that several epigenetic mechanisms are likely modulating hypnozoite formation or persistence and provide an avenue for the discovery and development of improved radical cure antimalarials.

Pathogens and microorganisms in the mangrove oyster Crassostrea gasar cultivated in an estuarine environment in Northeast Brazil.

Estuaries are important ecosystems due to the ecological services they provide, acting as nurseries for many species of fish and invertebrates, and are also used as environments for the extraction and cultivation of mollusks. Oysters are animals that filter water to obtain oxygen and nutrients. In this process, they can bioaccumulate microorganisms and chemical substances in their tissues. The growth of mollusk culture in Northeastern Brazil requires the health identification of cultivated oysters through the quantification of the potentially harmful microbiota accumulated in the animals. Therefore, the present work aims to quantify and identify bacteria and possible pathogens found in the tissues of cultivated oysters and their culture waters. The Most Probable Number of Coliforms (MPN) in oysters and water were considered suitable according to the Brazilian current legislation, Vibrio sp. obtained low colonization and Salmonella sp. was not observed. The prevalence of microorganisms potentially pathogenic to oysters was 33.7%, highlighting metazoans and Nematopsis sp., however, the intensity of the infestation of these organisms was moderate. The low contamination of oysters demonstrates that this culture environment is promising for this activity. However, continuous environmental and sanitary monitoring is fundamental to guarantee the safety of the culture waters and the sustainability of aquaculture activities.

PfMORC protein regulates chromatin accessibility and transcriptional repression in the human malaria parasite, P. falciparum.

The environmental challenges the human malaria parasite, Plasmodium falciparum, faces during its progression into its various lifecycle stages warrant the use of effective and highly regulated access to chromatin for transcriptional regulation. Microrchidia (MORC) proteins have been implicated in DNA compaction and gene silencing across plant and animal kingdoms. Accumulating evidence has shed light into the role MORC protein plays as a transcriptional switch in apicomplexan parasites. In this study, using CRISPR/Cas9 genome editing tool along with complementary molecular and genomics approaches, we demonstrate that PfMORC not only modulates chromatin structure and heterochromatin formation throughout the parasite erythrocytic cycle, but is also essential to the parasite survival. Chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) experiments suggest that PfMORC binds to not only sub-telomeric regions and genes involved in antigenic variation but is also most likely a key modulator of stage transition. Protein knockdown experiments followed by chromatin conformation capture (Hi-C) studies indicate that downregulation of PfMORC induces the collapse of the parasite heterochromatin structure leading to its death. All together these findings confirm that PfMORC plays a crucial role in chromatin structure and gene regulation, validating this factor as a strong candidate for novel antimalarial strategies.

Corrigendum: Palaeo leaf economics reveal a shift in ecosystem function associated with the end-Triassic mass extinction event.

This corrects the article DOI: 10.1038/nplants.2017.104.

Palaeo leaf economics reveal a shift in ecosystem function associated with the end-Triassic mass extinction event.

Climate change is likely to have altered the ecological functioning of past ecosystems, and is likely to alter functioning in the future; however, the magnitude and direction of such changes are difficult to predict. Here we use a deep-time case study to evaluate the impact of a well-constrained CO2-induced global warming event on the ecological functioning of dominant plant communities. We use leaf mass per area (LMA), a widely used trait in modern plant ecology, to infer the palaeoecological strategy of fossil plant taxa. We show that palaeo-LMA can be inferred from fossil leaf cuticles based on a tight relationship between LMA and cuticle thickness observed among extant gymnosperms. Application of this new palaeo-LMA proxy to fossil gymnosperms from East Greenland reveals significant shifts in the dominant ecological strategies of vegetation found across the Triassic-Jurassic transition. Late Triassic forests, dominated by low-LMA taxa with inferred high transpiration rates and short leaf lifespans, were replaced in the Early Jurassic by forests dominated by high-LMA taxa that were likely to have slower metabolic rates. We suggest that extreme CO2-induced global warming selected for taxa with high LMA associated with a stress-tolerant strategy and that adaptive plasticity in leaf functional traits such as LMA contributed to post-warming ecological success.

A field reciprocal transplant experiment reveals asymmetric costs of migration between lake and river ecotypes of three-spined sticklebacks (Gasterosteus aculeatus).

Theory of local adaptation predicts that nonadapted migrants will suffer increased costs compared to local residents. Ultimately this process can result in the reduction of gene flow and culminate in speciation. Here, we experimentally investigated the relative fitness of migrants in foreign habitats, focusing on diverging lake and river ecotypes of three-spined sticklebacks. A reciprocal transplant experiment performed in the field revealed asymmetric costs of migration: whereas mortality of river fish was increased under lake conditions, lake migrants suffered from reduced growth relative to river residents. Selection against migrants thus involved different traits in each habitat but generally contributed to bidirectional reduction in gene flow. Focusing particularly on the parasitic environments, migrant fish differed from resident fish in the parasite community they harboured. This pattern correlated with both cellular phenotypes of innate immunity as well as with allelic variation at the genes of the major histocompatibility complex. In addition to showing the costs of migration in three-spined sticklebacks, this study highlights the role of asymmetric selection particularly from parasitism in genotype sorting and in the emergence of local adaptation.

[Hygiene in Urological Surgeries - Results of the Health Authority's Visit to all Urological Surgeries in Braunschweig]. / Hygiene in urologischen Praxen - Ergebnisse der Besichtigung aller urologischen Praxen in Braunschweig durch das Gesundheitsamt.

Following a patient complaint, the Health Department carried out a hygiene inspection of a urological practice in Braunschweig in February 2013. The topic of the complaint was that a patient assumed having acquired a resistant pathogen in the practice. In the subsequent visit, significant hygiene defects were found, particularly with regard to the processing of medical devices. This led to a decision to commit all urological practices in Braunschweig to hygiene inspections as part of a priority project. In retrospect, the hygiene surveys were justified. Deficiencies included inadequate preparation of medical products, procedures in practice inconsistent with hygiene plans, poor knowledge of hygiene procedures among assistant staff and doctors, lack of expertise of assistant staff and lack of hygiene risk awareness by doctors. Positive experiences were: open communication in a good atmosphere with the Practice managers, willingness to change, good cooperation between the Health Authority and the Labor Inspectorate and Physicians' Association. The claimed deficits were corrected by spring 2014 by the practice operators. The consulting expertise of the health authorities was made use of continuously.

[Ischemic renal disease and renal artery stenosis]. / Ischämische Nephropathie und Nierenarterienstenose.

Severe renal artery stenosis may cause renovascular hypertension; in case of bilateral narrowing or in a stenotic solitary or transplant kidney, renal insufficiency (ischemic renal disease) or rarely pulmonary flash edema may occur. In most cases arteriosclerotic disease is the underlying cause; less prevalent are the various manifestations of fibromuscular disease. Renal artery stenosis may be treated by revasularization, using either percutaneous (balloon angioplasty, stenting) or rarely open surgical procedures, both with excellent primary patency rates. However, randomized trials of renal artery angioplasty or stenting in patients with arteriosclerotic lesions have failed to demonstrate a longer-term benefit with regard to hypertension control and renal dysfunction over medical management alone. Careful patient selection is essential to maximize the potential benefit (e.g., in patients with refractory hypertension, progressive renal failure or recurrent pulmonary flash edema).

[Current management of renal artery stenosis]. / Aktuelle Strategien in der Therapie der Nierenarterienstenose.

Severe renal artery stenosis may cause renovascular hypertension; in case of bilateral narrowing or in a stenotic solitary kidney, renal insufficiency (ischemic kidney disease) or rarely pulmonary flush edema may occur. Renal artery stenosis may be treated by revascularization, using either percutaneous (balloon angioplasty, stenting) or less common open surgical procedures, both with excellent primary patency rates. However, randomized trials of renal artery angioplasty or stenting have failed to demonstrate a longer-term benefit with regard to blood pressure control and renal function over medical management alone (except for fibromuscular disease). Furthermore, endovascular procedures are associated with substantial risks. It has not yet been demonstrated that renal revascularization leads to a prolongation of event-free survival. Careful patient selection is essential to maximize the potential benefit.

Major histocompatibility complex polymorphism: dynamics and consequences of parasite-mediated local adaptation in fishes.

Parasitism is a common form of life and represents a strong selective pressure for host organisms. In response to this evolutionary pressure, vertebrates have developed genetically coded defences such as the major histocompatibility complex (MHC). Mechanisms of parasite-mediated selection not only maintain outstanding polymorphism in these genes but have also been proposed to further promote host population divergence and ultimately speciation because it can drive evolution of local adaptation in which MHC genes play a crucial role. This review first highlights the dynamics and complexity of parasite-mediated selection in natural systems, which not only depends on dominating parasite strategies and on the taxonomic diversity of the parasite community but also includes the differences in parasite communities between habitats and niches, creating divergent selection on locally adapted populations. Then the different ways in which MHC genes potentially allow vertebrates to respond to these dynamics and to adapt locally are outlined. Finally, it is proposed that varying selection strength in time and space may lead to variation in the strength of precopulatory reproductive isolation which has evolved to maintain local adaptation.

MHC-based mate choice combines good genes and maintenance of MHC polymorphism.

Polymorphic genes of the major histocompatibility complex (MHC) are regarded as essential genes for individual fitness under conditions of natural and sexual selection. To test this hypothesis, we investigated the ultimate individual fitness trait--that of reproductive success. We used three-spined sticklebacks (Gasterosteus aculeatus) in seminatural enclosures, located in natural breeding areas where the experimental fish had been caught. During their reproductive period, fish were exposed continuously to their natural sympatric parasites. By genotyping almost 4000 eggs with nine microsatellites, we determined parenthood and inferred female mating decision. We found that with reference to their own MHC profile, female sticklebacks preferred to mate with males sharing an intermediate MHC diversity. In addition, males with a specific MHC haplotype were bigger and better at fighting a common parasite (Gyrodactylus sp.). This translated directly into Darwinian fitness since fish harbouring this specific MHC haplotype were more likely to be chosen and had a higher reproductive output. We conclude that females also based their mating decision on a specific MHC haplotype conferring resistance against a common parasite. This identifies and supports 'good genes'. We argue that such an interaction between host and parasite driving assortative mating is not only a prerequisite for negative frequency-dependent selection--a potential mechanism to explain the maintenance of MHC polymorphism, but also potentially speciation.

Disentangling the role of MHC-dependent 'good genes' and 'compatible genes' in mate-choice decisions of three-spined sticklebacks Gasterosteus aculeatus under semi-natural conditions.

To investigate and disentangle the role of major histocompatibility complex (MHC)-based 'good genes' and 'compatible genes' in mate choice, three-spined sticklebacks Gasterosteus aculeatus with specific MHC IIB genotypes were allowed to reproduce in an outdoor enclosure system. Here, fish were protected from predators but encountered their natural parasites. Mate choice for an intermediate genetic distance between parental MHC genotypes was observed, which would result in intermediate diversity in the offspring, but no mate choice based on good genes was found under the current semi-natural conditions. Investigation of immunological variables revealed that the less-specific innate immune system was more active in individuals with a genetically more divergent MHC allele repertoire. This suggests the need to compensate for an MHC-diminished T-cell repertoire and potentially explains the observed mate choice for intermediate MHC genetic distance. The present findings support a general pattern of mate choice for intermediate MHC diversity (i.e. compatible genes). In addition, the potentially dynamic role of MHC good genes in mate choice under different parasite pressures is discussed in the light of present and previous results.

Treatment of reduced bone density with ibandronate in dialysis patients.

Bisphosphonates inhibit bone resorption and are widely used to treat osteolytic metastases and osteoporosis. Renal osteodystrophy patients have continuous bone loss due to chronically elevated parathyroid hormone (PTH). In this open-label study, ibandronate was evaluated for the treatment of reduced bone density in renal osteodystrophy. Patients (n=16) with end-stage renal disease (ESRD) and regular hemodialysis schedules were recruited. All patients had low bone mineral density (BMD; lumbar spine T-score <-1.0) and elevated PTH levels (>2-fold higher than normal). Patients received ibandronate 2 mg every 4 weeks for 48 weeks. Serum levels of markers of bone turnover, calcium, phosphate and magnesium were determined (week 0 [prior to treatment] vs. at week 48). BMD (n=11) increased significantly from 88.94 +/- 31.68 mg/mL calcium hydroxylapatite (CaHA) to 93.51 +/- 35.36 mg/mL CaHA (p=0.032). T-scores increased significantly from -3.08 +/- 1.11 to -2.78 +/- 1.27 (p<0.01). The mean PTH level initially increased before dropping to 18.99 pmol/L at week 48 (7.99% decrease vs. week 0; not significant). Bone turnover markers decreased, whereas calcium and magnesium levels remained stable and within normal ranges. Phosphate levels were variable throughout the study. Two patients did not complete the study, and 3 patients died due to concomitant cardiovascular disease. Calcitriol dosage increased from 1.5 to 1.83 microg/week. In patients with renal osteodystrophy and ESRD, ibandronate significantly increased BMD and decreased bone turnover.

Autonomic function in children and adolescents with neurocardiogenic syncope.

BACKGROUND: This study aimed to clarify whether children with neurocardiogenic syncope (NCS) differ from healthy control subjects in baseline heart rate variability (HRV) and in their response to orthostatic stress induced by active standing and tilt table. METHODS: This study analyzed the difference between 55 children with a history of NCS or presyncopal symptoms (PS) and healthy control subjects. Measurements included short-term HRV during resting position, tilt table testing, and active standing. Time and frequency domain HRV parameters were computed. RESULTS: Both the NCS and PS children differed significantly from healthy control subjects during resting position. During tilt table testing, nearly all NCS and PS subjects differed significantly from the control group in calculated HRV parameters. Moreover, for the low-frequency power and total power, the confidence intervals did not overlap. CONCLUSIONS: The findings suggest that chronic autonomic differences exist between healthy children and patients with NCS and PS. These changes could be detected even by short-term HRV recordings. The tilt table maneuver provoked the most prominent differences between the groups. Low-frequency power and total power during tilt table testing helps to detect children with NCS.

Prospective, randomized controlled trial on Lactobacillus rhamnosus in infants with moderate to severe atopic dermatitis.

BACKGROUND: A reduction of symptoms of atopic dermatitis (AD) in small infants by the administration of Lactobacillus rhamnosus has been reported in a few studies. One study with older children and adolescents failed to show any effect. OBJECTIVES: We conducted a prospective study to reassess the efficacy of orally administered L. rhamnosus strain GG (LGG) in infants with AD. METHODS: In a randomized, double-blind, placebo-controlled study, 54 infants aged 1-55 months with moderate to severe AD were randomized to daily 10 x 10(9) colony-forming units of LGG or to placebo during an 8-week intervention phase. Emollients, class I-II topical corticosteroids and antihistamines were permitted. RESULTS: The treatment with LGG was well tolerated. At the end of treatment there were no significant differences between the groups with respect to clinical symptoms (SCORAD, pruritus, sleep loss), the use of topical corticosteroids and antihistamines, immunological parameters, or health-related quality of life of the parents. CONCLUSIONS: Our results could not confirm LGG as an effective treatment of AD in infancy.

High bone-binding capacity of ibandronate in hemodialysis patients.

Bisphosphonates are a potential therapy for osteoclast-mediated bone disease, such as renal osteodystrophy. This study evaluated ibandronate bone-binding in patients with secondary hyperparathyroidism and renal osteodystrophy and examined whether there is a correlation with bone metabolism parameters. Sixteen patients with end-stage renal disease and secondary hyperparathyroidism receiving regular hemodialysis were recruited to this 12-week trial. Intravenous ibandronate 2 mg was administered for 5 min every 4 weeks directly after hemodialysis. Ibandronate levels were measured 15 min after infusion and at trough levels before the next hemodialysis. Serological markers of bone metabolism were also measured. After the first infusion, the peak ibandronate level was 154 +/- 75.1 ng/ml and the trough level was 2.7 +/- 1.7 ng/ml. At week 12, peak and trough ibandronate levels were 164.8 +/- 89.9 ng/ml and 3.2 +/- 2.6 ng/ml, respectively. Ibandronate bone uptake was 98.0% at first application and 98.4% at week 12. In patients with remaining diuresis, ibandronate urine excretion was < 0.001% of the administered dose. There was no correlation of ibandronate bone-binding with parameters of osteoclast activity or parathyroid hormone (PTH). The correlation with markers of osteoblast activity was significant but weak. Ibandronate had a bone-binding capacity of approximately 98% in hemodialysis patients. After repeated dosing ibandronate bone-uptake remained stable and was independent of osteoclast activity or PTH levels. Due to the high bone-binding of ibandronate in these patients, a 2 mg dose of intravenous ibandronate is equivalent to a 4-5 mg dose of ibandronate in patients with normal renal function.