Insights into SARS-CoV-2 in Angola during the COVID-19 peak: Molecular epidemiology and genome surveillance

Background

In Angola, COVID-19 cases have been reported in all provinces, resulting in >105,000 cases and >1900 deaths. However, no detailed genomic surveillance into the introduction and spread of the SARS-CoV-2 virus has been conducted in Angola. We aimed to investigate the emergence and epidemic progression during the peak of the COVID-19 pandemic in Angola.

Methods

We generated 1210 whole-genome SARS-CoV-2 sequences, contributing West African data to the global context, that were phylogenetically compared against global strains. Virus movement events were inferred using ancestral state reconstruction.

Results

The epidemic in Angola was marked by four distinct waves of infection, dominated by 12 virus lineages, including VOCs, VOIs, and the VUM C.16, which was unique to South-Western Africa and circulated for an extended period within the region. Virus exchanges occurred between Angola and its neighboring countries, and strong links with Brazil and Portugal reflected the historical and cultural ties shared between these countries. The first case likely originated from southern Africa.

Conclusion

A lack of a robust genome surveillance network and strong dependence on out-of-country sequencing limit real-time data generation to achieve timely disease outbreak responses, which remains of the utmost importance to mitigate future disease outbreaks in Angola.

Radiosynthesis and in vivo evaluation of a ¹⁸F-labelled styryl-benzoxazole derivative for β-amyloid targeting

The formation of β-amyloid deposits is considered a histopathological feature of Alzheimer's disease (AD). In vivo molecular imaging by means of amyloid-avid radiotracers will allow for an early and conclusive diagnostic of AD. Herein, we describe the radiosynthesis of the radiofluorinated styryl benzoxazole derivative [¹⁸F]-[2-[N-methyl-N-(2'-fluoroethyl)-4'-aminostyryl]benzoxazole] ([¹⁸F]-1) and its pre-clinical evaluation, including metabolic and biodistribution studies in male Wistar rats. The in vivo biological evaluation of [¹⁸F]-1 showed that this new radiotracer has a moderate brain uptake with a slow brain washout and a poor in vivo stability.

Comparative in vitro and in vivo antimalarial activity of the indole alkaloids ellipticine, olivacine, cryptolepine and a synthetic cryptolepine analog

Indole alkaloids ellipticine (1), cryptolepine triflate (2a), rationally designed 11-(4-piperidinamino)cryptolepine hydrogen dichloride (2b) and olivacine (3) (an isomer of 1) were evaluated in vitro against Plasmodium falciparum and in vivo in Plasmodium berghei-infected mice. 1-3 inhibited P. falciparum (IC₅₀≤1.4 μM, order of activity: 2b>1>2a>3). In vitro toxicity to murine macrophages was evaluated and revealed selectivity indices (SI) of 10-12 for 2a and SI>2.8×10² for 1, 2b and 3. 1 administered orally at 50mg/kg/day was highly active against P. berghei (in vivo inhibition compared to untreated control (IVI)=100%, mean survival time (MST)>40 days, comparable activity to chloroquine control). 1 administered orally and subcutaneously was active at 10 mg/kg/day (IVI=70-77%; MST=27-29 days). 3 exhibited high oral activity at ≥50 mg/kg/day (IVI=90-97%, MST=23-27 days). Cryptolepine (2a) administered orally and subcutaneously exhibited moderate activity at 50mg/kg/day (IVI=43-63%, MST=24-25 days). At 50 mg/kg/day, 2b administered subcutaneously was lethal to infected mice (MST=3 days) and moderately active when administered orally (IVI=45-55%, MST=25 days). 1 and 3 are promising compounds for development of antimalarials.

Indoloquinolines as scaffolds for drug discovery

Traditional medicines have contributed greatly over the centuries to the discovery and development of new therapeutic agents and indoloquinoline alkaloids may represent a new class of drug leads. Cryptolepine (5-methyl-5Hindolo[3,2-b]quinoline), neocryptolepine (5-methyl-5H-indolo[2,3-b]quinoline), isocryptolepine (5-methyl-5H-indolo[3,2-c]quinoline, extracted from the African medicinal plant Cryptolepis sanguinolenta, and isoneocryptolepine (5-methyl-5Hindolo[2,3-c]quinoline), which has never been found in nature, are isomeric tetracyclic compounds of particular interest due to their broad spectrum of biological activities including antiparasitic, antifungal, antibacterial, cytotoxic, anti-inflammatory and antihyperglycaemic. As a result, in the last 30 years hundreds of indoloquinoline analogues were synthesized and their biological activities evaluated. In this paper, we present an overview of the potential of indoloquinolines as scaffolds in drug discovery by reviewing the in vitro and in vivo biological activities of natural and synthetic analogues, as well as the proposed mechanisms of action and structure-activity relationships.

Photocatalytic and combined anaerobic-photocatalytic treatment of textile dyes

A photocatalytic process based on immobilized titanium dioxide was used to treat crude solutions of azo, anthraquinone and phthalocyanine textile dyes. In addition, the process was applied to the treat autoxidized chemically reduced azo dyes, i.e. representatives of recalcitrant dye residues after biological sequential anaerobic-aerobic treatment. Photocatalysis was able to remove more than 90% color from crude as well as autoxidized chemically reduced dye solutions. UV-absorbance and COD were also removed but to a lower extent (50% in average). The end products of photocatalytic treatment were not toxic toward methanogenic bacteria. The results demonstrate that photocatalysis can be used as a pre- or post-treatment method to biological anaerobic treatment of dye-containing textile wastewater.

Structural elucidation of natural 2-hydroxy di- and tricarboxylic acids and esters, phenylpropanoid esters and a flavonoid from Autonoë madeirensis using gas chromatographic/electron ionization, electrospray ionization and tandem mass spectrometric techniques

The chemical composition of Autonoë madeirensis bulbs was characterized as part of a systematic phytochemical study of this species. The compounds reported were mainly identified on the basis of gas chromatography/electron ionization, electrospray ionization and tandem mass spectrometry. The structures of the pure compounds were also characterized by means of other physical and spectroscopic data (m.p., IR, UV, NMR). The compounds identified were 2-hydroxy di- and tricarboxylic acids and esters (malic acid, citric acid and their methyl and ethyl esters), cis- and trans-hydroxycinnamic esters (methyl and ethyl p-coumarate and methyl ferulate) and a new flavone diglucoside, 7-O-[beta-glucosyl-(1-->2)-O-beta-glucosyl]apigenin, the interglucosidic linkage (1-->2) of which is, to the best of our knowledge, reported for the first time in a diglucoside of apigenin. The results may contribute to the chemotaxonomy of the Autonoë genus and lead to a rapid tool for the systematic characterization of these compounds in plant extracts.

Cationic Re(V) oxo complexes with poly(pyrazolyl)borates: synthesis, characterization, and stability

Cationic Re(V) oxo compounds of the type [ReO(OSiMe3)(eta 2-B(pz)4)(L)2]X [X = Cl, L = 4-(NMe2)C5H4N (1), 1-Meimz (1-methylimidazole; 2), 1/2 dmpe (1,2-bis(dimethylphosphino)ethane; 3), py (4a); X = I, L = py (4b)] can be prepared by reacting trans-[ReO2(eta 2-B(pz)4)(L)2] with XSiMe3. In solution, cations 1-4 are reactive species, and those with unidentate nitrogen donor ligands (1, 2, and 4) rearrange into the neutral derivatives [ReO(Cl)(OSiMe3)(eta 2-B(pz)4)(L)] [L = py (5), 4-(NMe2)C5H4N (6), 1-Meimz (7)], which are also reported herein. Compounds 1-3 and 5-7 have been fully characterized by the usual spectroscopic techniques, which in some cases includes X-ray crystallographic analysis (3, 6, and 7). Compound 3 crystallizes from CH2Cl2/n-hexane as yellow crystals with one molecule of CH2Cl2 solvent, and compounds 6 and 7 crystallize from THF/n-hexane as violet and red crystals, respectively, with one molecule of THF solvent in the case of 6. Crystallographic data: 3, orthorhombic space group Pn2(1)a, a = 11.311(2) A, b = 19.135(2) A, c = 15.443(2) A, V = 3342.4(8) A3, Z = 4; 6, triclinic space group P1, a = 8.7179(11) A, b = 12.5724(8) A, c = 17.750(2) A, alpha = 70.454(7) degrees, beta = 77.935(9) degrees, gamma = 77.129(8) degrees, V = 1768.1(3) A3, Z = 2; 7, monoclinic space group P2(1)/c, a = 16.356(2) A, b = 20.384(3) A, c = 17.360(3) A, beta = 106.971(12) degrees, V = 5535.8(14) A3, Z = 8.

Steroidal alkaloids from Cryptolepis obtusa

Two novel diglycosylated steroidal alkaloids of 5 delta-pregnene nucleus, named obtusine-20(R)-O-[beta-thevetopyranosyl-(1-->4)-beta-cyma ropyranoside] and obtusolactam-20(R)-O-[beta-thevetopyranosyl-(1-->4)-beta- cymaropyranoside], together with the known beta-sitosteryl-3-O-beta-glucopyranoside were isolated from the roots of Cryptolepis obtusa N. E. Br.

Antiplasmodial activity of Cryptolepis sanguinolenta alkaloids from leaves and roots

The roots of Cryptolepis sanguinolenta have been investigated for their chemical composition since 1931 but so far no studies on the leaves have been reported although they are used in traditional medicine in Guinea-Bissau. Two new alkaloids identified as cryptolepinoic acid (1) and methyl cryptolepinoate (2) and the known alkaloids cryptolepine (4), hydroxycryptolepine (5/5a) and quindoline (6), were isolated from the ethanolic and chlorophormic leaf extracts. Aqueous and ethanolic extracts of the leaves and roots and seven alkaloids isolated from those extracts were tested in vitro against Plasmodium falciparum K1 (multidrug-resistant strain) and T996 (chloroquine-sensitive clone). All the extracts were shown to give 90% inhibition of P. falciparum K1 growth at concentrations < 23 micrograms/ml. Cryptolepine (4) was the most active alkaloid tested with IC50 values (0.23 microM to K1; 0.059 microM to T996) comparable with chloroquine (0.26 microM to K1; 0.019 microM to T996). The indolobenzazepine alkaloid cryptoheptine (7) was the second most active with IC50 values of 0.8 microM (K1) and 1.2 microM (T996). Cryptolepinoic acid (1) showed no significant activity while its ethyl ester derivative 3 was active against P. falciparum K1 (IC50 = 3.7 microM). All the indoloquinoline alkaloids showed cross-resistance with chloroquine but not the indolobenzazepine alkaloid 7. It was noticed that alkaloids with weakly basic characteristics were active whereas other structurally related alkaloids with different acid-base profiles were inactive. These observations are in agreement with the antimalarial mechanism of action for quinolines.

In vitro antibacterial screening of Cryptolepis sanguinolenta alkaloids

The ethanol and aqueous crude extracts and five alkaloids isolated from the roots of Crytolepis sanguinolenta (Lindl.) Schlechter were screened for antibacterial activity against 7 reference strains by the twofold serial broth microdilution assay. The ethanol extract and the alkaloids cryptolepine and cryptoheptine inhibited the growth of all strains tested except that of Pseudomonas aeruginosa.

Cryptolepis sanguinolenta activity against diarrhoeal bacteria

Cryptolepine is the main alkaloid of Cryptolepis sanguinolenta (Lindl.) Schlechter, a plant used in traditional medicine in West Africa. The minimal inhibitory concentrations (MICs) of cryptolepine, ethanol and aqueous extracts of Cryptolepis sanguinolenta root were determined for 65 strains of Campylobacter jejuni, 41 strains of Campylobacter coli isolated from sporadic cases of gastroenteritis in Portugal and 86 strains of Vibrio cholerae isolated from patients with enteric infections in Angola, Brazil and Portugal. The ethanol extract activity against Campylobacter strains (MIC90% = 25 micrograms/ml) is higher than that of co-trimoxazole and sulfamethoxazole and Campylobacter strains susceptibility for cryptolepine (MIC90% = 12.5 micrograms/ml) is equal for ampicillin. The ethanol extract and cryptolepine show some activity against the Vibrio cholerae strains, although their activities are lower than that of tetracycline. The results suggest that these roots could be a therapeutic alternative for bacterial etiologic diarrhoea in West Africa.

Preparation and biological characteristics of 99mTc-diol a renal agent

The present work concerns the production of 1,2-dihydroxypropyl-1-phosphonic acid (diol) by acid hydrolysis of (-cis) 1,2-epoxypropylphosphonic acid (phosphomycin), and its formulation as a kit easily labeled with [99mTc]pertechnetate. Biodistribution studies and whole-body autoradiographies in mice show that 99mTc-diol has a specific affinity for the kidneys: it is rapidly cleared from the blood and excreted in urine (12.09 +/- 6.40% ID are excreted in urine at 5 min and 70.81 +/- 2.41% ID at 30 min post-injection). Part of the injected activity remains in the kidney cortex sufficiently long to permit kidney imaging (5.66 +/- 0.91% ID is still in kidneys 1 h post-injection). In comparison with other agents which also localize in the kidney cortex, such as 99mTc-DMSA and 99mTc-glucoheptonate (99mTc-GHA), the main differences are the following: the peak of renal activity is reached early in the 5 min post-injection period for 99mTc-diol, only at about 10 min post-injection for 99mTc-GHA and after 3 h post-injection for 99mTc-DMSA. The uptake of 99mTc-diol by other organs, especially by bones, is much smaller than in the case of 99mTc-DMSA (1.25 +/- 0.11% ID of 99mTc-diol compared to 11.31 +/- 1.17% ID of 99mTc-DMSA, 1 h post-injection). Unlike 99mTc-DMSA, the biodistribution of 99mTc-diol is not significantly influenced by acid-base imbalance, in addition, its renal uptake decreases in the presence of probenecid whereas its urinary excretion increases.(ABSTRACT TRUNCATED AT 250 WORDS)