Antifungal Development and the Urgency of Minimizing the Impact of Fungal Diseases on Public Health

Fungal infections are a major public health problem resulting from the lack of public policies addressing these diseases, toxic and/or expensive therapeutic tools, scarce diagnostic tests, and unavailable vaccines. In this Perspective, we discuss the need for novel antifungal alternatives, highlighting new initiatives based on drug repurposing and the development of novel antifungals.

Confinement and Exciton Binding Energy Effects on Hot Carrier Cooling in Lead Halide Perovskite Nanomaterials

The relaxation of the above-gap ("hot") carriers in lead halide perovskites (LHPs) is important for applications in photovoltaics and offers insights into carrier-carrier and carrier-phonon interactions. However, the role of quantum confinement in the hot carrier dynamics of nanosystems is still disputed. Here, we devise a single approach, ultrafast pump-push-probe spectroscopy, to study carrier cooling in six different size-controlled LHP nanomaterials. In cuboidal nanocrystals, we observe only a weak size effect on the cooling dynamics. In contrast, two-dimensional systems show suppression of the hot phonon bottleneck effect common in bulk perovskites. The proposed kinetic model describes the intrinsic and density-dependent cooling times accurately in all studied perovskite systems using only carrier-carrier, carrier-phonon, and excitonic coupling constants. This highlights the impact of exciton formation on carrier cooling and promotes dimensional confinement as a tool for engineering carrier-phonon and carrier-carrier interactions in LHP optoelectronic materials.

Detection and significance of neuronal autoantibodies in patients with meningoencephalitis in Vientiane, Lao PDR

BACKGROUND

The importance of autoimmune encephalitis and its overlap with infectious encephalitides are not well investigated in South-East Asia.

METHODS

We report autoantibody testing, using antigen-specific live cell-based assays, in a series of 134 patients (cerebrospinal fluid and sera) and 55 blood donor controls (sera), undergoing lumbar puncture for suspected meningoencephalitis admitted in Vientiane, Lao People's Democratic Republic (PDR).

RESULTS

Eight of 134 (6%) patients showed detectable serum neuronal autoantibodies, against the N-methyl-D-aspartate and gamma-aminobutyric acid A receptors (NMDAR and GABAAR), and contactin-associated protein-like 2 (CASPR2). Three of eight patients had accompanying autoantibodies in cerebrospinal fluid (two with NMDAR and one with GABAAR antibodies), and in two of these the clinical syndromes were typical of autoimmune encephalitis. Three of the other five patients had proven central nervous system infections, highlighting a complex overlap between diverse infectious and autoimmune causes of encephalitis. No patients in this cohort were treated with immunotherapy, and the outcomes were poor, with improvement observed in a single patient.

CONCLUSIONS

In Lao PDR, autoimmune encephalitis is underdiagnosed and has a poor prognosis. Empiric immunotherapy should be considered after treatable infectious aetiologies are considered unlikely. Awareness and diagnostic testing resources for autoimmune encephalitis should be enhanced in South-East Asia.

Biosynthesis of the Unusual Carbon Skeleton of Nocuolin A

Nocuolin A is a cytotoxic cyanobacterial metabolite that is proposed to be produced by enzymes of the noc biosynthetic gene cluster. Nocuolin A features a 1,2,3-oxadiazine moiety, a structural feature unique among natural products and, so far, inaccessible through organic synthesis, suggesting that novel enzymatic chemistry might be involved in its biosynthesis. This heterocycle is substituted with two alkyl chains and a 3-hydroxypropanoyl moiety. We report here our efforts to elucidate the origin of the carbon skeleton of nocuolin A. Supplementation of cyanobacterial cultures with stable isotope-labeled fatty acids revealed that the central C13 chain is assembled from two medium-chain fatty acids, hexanoic and octanoic acids. Using biochemical assays, we show that a fatty acyl-AMP ligase, NocH, activates both fatty acids as acyl adenylates, which are loaded onto an acyl carrier protein domain and undergo a nondecarboxylative Claisen condensation catalyzed by the ketosynthase NocG. This enzyme is part of a phylogenetically well-defined clade within similar genomic contexts. NocG presents a unique combination of characteristics found in other ketosynthases, namely in terms of substrate specificity and reactivity. Further supplementation experiments indicate that the 3-hydroxypropanoyl moiety of 1 originates from methionine, through an as-yet-uncharacterized mechanism. This work provides ample biochemical evidence connecting the putative noc biosynthetic gene cluster to nocuolin A and identifies the origin of all its carbon atoms, setting the stage for elucidation of its unusual biosynthetic chemistry.

Metallodrugs are unique: opportunities and challenges of discovery and development

Metals play vital roles in nutrients and medicines and provide chemical functionalities that are not accessible to purely organic compounds. At least 10 metals are essential for human life and about 46 other non-essential metals (including radionuclides) are also used in drug therapies and diagnostic agents. These include platinum drugs (in 50% of cancer chemotherapies), lithium (bipolar disorders), silver (antimicrobials), and bismuth (broad-spectrum antibiotics). While the quest for novel and better drugs is now as urgent as ever, drug discovery and development pipelines established for organic drugs and based on target identification and high-throughput screening of compound libraries are less effective when applied to metallodrugs. Metallodrugs are often prodrugs which undergo activation by ligand substitution or redox reactions, and are multi-targeting, all of which need to be considered when establishing structure-activity relationships. We focus on early-stage in vitro drug discovery, highlighting the challenges of evaluating anticancer, antimicrobial and antiviral metallo-pharmacophores in cultured cells, and identifying their targets. We highlight advances in the application of metal-specific techniques that can assist the preclinical development, including synchrotron X-ray spectro(micro)scopy, luminescence, and mass spectrometry-based methods, combined with proteomic and genomic (metallomic) approaches. A deeper understanding of the behavior of metals and metallodrugs in biological systems is not only key to the design of novel agents with unique mechanisms of action, but also to new understanding of clinically-established drugs.

Salvia ceratophylla L. from South of Jordan: new insights on chemical composition and biological activities

In Jordan, Salvia ceratophylla L. is traditionally used in the treatment of cancer, microbial infections, and urinary disorders. This study aimed: (1) to chemically characterize S. ceratophylla essential oil (EO) from South Jordan, by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS); and (2) to evaluate in vitro the cytotoxic, anti-inflammatory, and antiprotozoal activities of the EO, it's predominant components, and the hexane (A), ethyl acetate (B), methanol (C) and crude-methanol extracts (D). The analysis revealed that the EO has 71 compounds, with linalool (54.8%) as main constituent. Only the hexane extract (A) showed some cytotoxic activity against SK-MEL, KB, BT-549, SK-OV-3, LLC-PK1 and VERO cells lines with IC₅₀ between 60 and > 100 µg/mL. The EO inhibited NO production (IC₅₀ 90 µg/mL) and NF-κB activity (IC₅₀ 38 µg/mL). The extracts A, B, and D inhibited NO production and NF- κB activity with IC₅₀ between 32 and 150 µg/mL. Linalool considerably inhibited NO production (IC₅₀ 18 µg/mL). The extracts tested did not exhibit antileishmanial activity. Regarding antitrypanosomal activity, the EO exhibited significant results with IC₅₀ 2.65 µg/mL. In conclusion, Jordan S. ceratophylla EO represents a rich source of linalool and bears a promising therapeutic potential for further antitrypanosomal drug development.

Network-wide abnormalities explain memory variability in hippocampal amnesia

Patients with hippocampal amnesia play a central role in memory neuroscience but the neural underpinnings of amnesia are hotly debated. We hypothesized that focal hippocampal damage is associated with changes across the extended hippocampal system and that these, rather than hippocampal atrophy per se, would explain variability in memory between patients. We assessed this hypothesis in a uniquely large cohort of patients (n = 38) after autoimmune limbic encephalitis, a syndrome associated with focal structural hippocampal pathology. These patients showed impaired recall, recognition and maintenance of new information, and remote autobiographical amnesia. Besides hippocampal atrophy, we observed correlatively reduced thalamic and entorhinal cortical volume, resting-state inter-hippocampal connectivity and activity in posteromedial cortex. Associations of hippocampal volume with recall, recognition, and remote memory were fully mediated by wider network abnormalities, and were only direct in forgetting. Network abnormalities may explain the variability across studies of amnesia and speak to debates in memory neuroscience.

The unbearable emptiness of tweeting-About journal articles

Enthusiasm for using Twitter as a source of data in the social sciences extends to measuring the impact of research with Twitter data being a key component in the new altmetrics approach. In this paper, we examine tweets containing links to research articles in the field of dentistry to assess the extent to which tweeting about scientific papers signifies engagement with, attention to, or consumption of scientific literature. The main goal is to better comprehend the role Twitter plays in scholarly communication and the potential value of tweet counts as traces of broader engagement with scientific literature. In particular, the pattern of tweeting to the top ten most tweeted scientific dental articles and of tweeting by accounts is examined. The ideal that tweeting about scholarly articles represents curating and informing about state-of-the-art appears not to be realized in practice. We see much presumably human tweeting almost entirely mechanical and devoid of original thought, no evidence of conversation, tweets generated by monomania, duplicate tweeting from many accounts under centralized professional management and tweets generated by bots. Some accounts exemplify the ideal, but they represent less than 10% of tweets. Therefore, any conclusions drawn from twitter data is swamped by the mechanical nature of the bulk of tweeting behavior. In light of these results, we discuss the compatibility of Twitter with the research enterprise as well as some of the financial incentives behind these patterns.

The period effect in the prevalence of proliferative diabetic retinopathy, gross proteinuria, and peripheral neuropathy in type 1 diabetes: A longitudinal cohort study

Aims

To investigate whether, for a specific duration of type 1 diabetes, there is a significant change in the prevalence of proliferative diabetic retinopathy, gross proteinuria and peripheral neuropathy in those more recently diagnosed with diabetes (a period effect), in the Wisconsin Epidemiologic Study of Diabetic Retinopathy. Where present, to determine how common risk factors for diabetic complications might be associated with it, and what might be driving it.

Materials and methods

Longitudinal cohort study with seven examination phases between 1980 and 2014. Multivariate logistic regression models and ordinal parameterization were used to test for and evaluate any period effect.

Results

There is a period effect in the prevalence of gross proteinuria and peripheral neuropathy (decreasing), as seen with proliferative diabetic retinopathy (p < 0.001). Adjusting for changing levels of common risk factors attenuates the period effect, particularly for proliferative diabetic retinopathy. For gross proteinuria and peripheral neuropathy, however there is a persistent period effect in spite of adjusting for the major risk factors.

Conclusions

There are period effects in the prevalence of proliferative diabetic retinopathy, gross proteinuria and peripheral neuropathy that cannot be fully explained by changes in common risk factors for complications of type 1 diabetes in this cohort. The role of other potential confounders warrants further exploration.