Many antibiotics inhibit the growth of sensitive bacteria by interfering with ribosome function. However, discovery of new protein synthesis inhibitors is curbed by the lack of facile techniques capable of readily identifying antibiotic target sites and modes of action. Furthermore, the frequent rediscovery of known antibiotic scaffolds, especially in natural product extracts, is timeconsuming and expensive and diverts resources that could be used toward the isolation of novel lead molecules. In order to avoid these pitfalls and improve the process of dereplication of chemically complex extracts, we designed a two-pronged approach for the characterization of inhibitors of protein synthesis (ChIPS) that is suitable for the rapid identification of the site and mode of action on the bacterial ribosome. First, we engineered antibiotic-hypersensitive Escherichia coli strains that contain only one rRNA operon. These strains are used for the rapid isolation of resistance mutants in which rRNA mutations identify the site of the antibiotic action. Second, we show that patterns of drug-induced ribosome stalling on mRNA, monitored by primer extension, can be used to elucidate the mode of antibiotic action. These analyses can be performed within a few days and provide a rapid and efficient approach for identifying the site and mode of action of translation inhibitors targeting the bacterial ribosome. Both techniques were validated using a bacterial strain whose culture extract, composed of unknown metabolites, exhibited protein synthesis inhibitory activity; we were able to rapidly detect the presence of the antibiotic chloramphenicol.

Despite medical progress, more than a billion people still suffer daily from parasitic infections. Vaccination is recognized as one of the most sustainable options to control parasitic diseases. However, the development of protective and therapeutic vaccines against tropical parasites has proven to be exceptionally challenging for both scientific and economic reasons. For certain parasitic diseases, traditional vaccine platforms are not well-suited, due to the complexity of the parasite life cycles and the parasite’s ability to evade the human immune system. An effective anti-parasite vaccine platform needs to have the ability to develop and test novel candidate antigens fast and at high-throughput; it further needs to allow for multivalent combinations and must evoke a strong and well-defined immune response. Anti-parasitic vaccines need to be safe and economically attractive, especially in the world’s low- and middle-income countries. This review evaluates the potential of in vitro transcribed mRNA vaccines as a new class of preventive and therapeutic vaccine technologies for parasitic infections.

BackgroundCisplatin (CP) is commonly used in the treatment of different types of cancer but nephrotoxicity has been a major limiting factor. Therefore, the present study aimed to study the possible protective effect of rutin against nephrotoxicity induced by cisplatin in rats.MethodsForty male Wistar albino rats were randomly divided into 4 groups. Rats of group 1 control group intraperitoneal (i.p.) received 2.5 ml/kg, group 2 CP group received single dose 5 mg/kg cisplatin i.p. group 3 rutin group orally received 30 mg/kg rutin group 4 (CP plus rutin) received CP and rutin as in group 2 and 3. Kidneys were harvested for histopathology and for the study the gene expression of c-Jun N-terminal kinases (JNK), Mitogen-activated protein kinase 4 (MKK4), MKK7, P38 mitogen-activated protein kinases (P38), tumor necrosis factors alpha (TNF-α), TNF Receptor-Associated Factor 2 (TRAF2), and interleukin-1 alpha (IL-1-α).ResultsThe cisplatin single dose administration to rats induced nephrotoxicity associated with a significant increase in blood urea nitrogen (BUN) and serum creatinine and significantly increase Malondialdehyde (MDA) in kidney tissues by 230 ± 5.5 nmol/g compared to control group. The animal treated with cisplatin showed a significant increase in the expression levels of the IL-1α (260%), TRFA2 (491%), P38 (410%), MKK4 (263%), MKK7 (412%), JNK (680%) and TNF-α (300%) genes compared to control group. Additionally, histopathological examination showed that cisplatin-induced interstitial congestion, focal mononuclear cell inflammatory, cell infiltrate, acute tubular injury with reactive atypia and apoptotic cells. Rutin administration attenuated cisplatin-induced alteration in gene expression and structural and functional changes in the kidney. Additionally, histopathological examination of kidney tissues confirmed gene expression data.ConclusionThe present study suggested that the anti-oxidant and anti-inflammatory effect of rutin may prevent CP-induced nephrotoxicity via decreasing the oxidative stress, inhibiting the interconnected ROS/JNK/TNF/P38 MAPK signaling pathways, and repairing the histopathological changes against cisplatin administration.

These findings suggested that apremilast can attenuate doxorubicin-induced cardiotoxicity via inhibition of oxidative stress mediated activation of nuclear factor-kappa B signaling pathways.

BackgroundCisplatin is widely used chemotherapeutic agent for cancer treatment with limited uses due to its neurotoxic side effect. The aim of this study was to determine the potential preventive effects of rutin on the brain of cisplatin- neurotoxic rat model.MethodsForty rats were divided into four groups. Group-1 (control group) was intra-peritoneal (IP) injected with 2.5 ml/kg saline. Group-2 (rutin group) was orally administrated 30 mg/kg rutin dissolved in water for 14 days. Group-3 (cisplatin group) was IP received 5 mg/kg cisplatin single dose. Group-4 (rutin and cisplatin group) was orally administrated 30 mg/kg rutin dissolved in water for 14 days with a single dose of 5 mg/kg cisplatin IP on day ten. Brain tissues from frontal cortex was used to extract RNA, the gene expression levels of paraoxonase-1 (PON-1), PON-2, PON-3, peroxisome proliferator-activated receptor delta (PPAR-δ), and glutathione peroxidase (GPx) was investigated by Real-time PCR.ResultsCisplatin significantly decreased the expression levels of PON-1, PON-3, PPAR-δ and GPX whereas significantly increased PON-2 expression levels. Co-administration of Rutin prevented the cisplatin-induced toxicity by restoring the alteration in the studied genes to normal values as in the control group.ConclusionThis study showed that Rutin has neuroprotective effect and reduces cisplatin- neurotoxicity with possible mechanism via the antioxidant pathway.

Antibiotics methymycin (MTM) and pikromycin (PKM), co-produced by Streptomyces venezuelae, represent minimalist macrolide protein synthesis inhibitors. Unlike other macrolides, which carry several side chains, a single desosamine sugar is attached to the macrolactone ring of MTM and PKM. In addition, the macrolactone scaffold of MTM is smaller than in other macrolides. The unusual structure of MTM and PKM and their simultaneous secretion by S. venezuelae bring about the possibility that two compounds would bind to distinct ribosomal sites. However, by combining genetic, biochemical and crystallographic studies, we demonstrate that MTM and PKM inhibit translation by binding to overlapping sites in the ribosomal exit tunnel. Strikingly, while MTM and PKM readily arrest the growth of bacteria, ∼40% of cellular proteins continue to be synthesized even at saturating concentrations of the drugs. Gel electrophoretic analysis shows that compared to other ribosomal antibiotics, MTM and PKM prevent synthesis of a smaller number of cellular polypeptides illustrating a unique mode of action of these antibiotics.

Ketolides are promising new antimicrobials effective against a broad range of Gram-positive pathogens, in part because of the low propensity of these drugs to trigger the expression of resistance genes. A natural ketolide pikromycin and a related compound methymycin are produced by Streptomyces venezuelae strain ATCC 15439. The producer avoids the inhibitory effects of its own antibiotics by expressing two paralogous rRNA methylase genes pikR1 and pikR2 with seemingly redundant functions. We show here that the PikR1 and PikR2 enzymes mono-and dimethylate, respectively, the N6 amino group in 23S rRNA nucleotide A2058. PikR1 monomethylase is constitutively expressed; it confers low resistance at low fitness cost and is required for ketolide-induced activation of pikR2 to attain high-level resistance. The regulatory mechanism controlling pikR2 expression has been evolutionary optimized for preferential activation by ketolide antibiotics. The resistance genes and the induction mechanism remain fully functional when transferred to heterologous bacterial hosts. The anticipated wide use of ketolide antibiotics could promote horizontal transfer of these highly efficient resistance genes to pathogens. Taken together, these findings emphasized the need for surveillance of pikR1/pikR2-based bacterial resistance and the preemptive development of drugs that can remain effective against the ketolide-specific resistance mechanism.ribosome | antibiotics | ketolides | resistance | macrolides

Carfilzomib (CFZ), is a potent, selective second generation proteasome inhibitor, used for the treatment of multiple myeloma. The aim of the present study was to investigate the possible protective effect of apremilast (AP) on the CFZ -induced cardiotoxicity. Rats were randomly divided into four groups: Group 1, served as the control group, received normal saline. Group 2, served as the toxic group, received CFZ (4 mg/kg, intraperitoneally [i.p.]). Groups 3 and 4, served as treatment groups, and received CFZ with concomitant oral administration of AP in doses of 10 and 20 mg/kg/day, respectively. In the present study, administration of CFZ resulted in a significant increase in serum aspartate transaminase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase-MB (CK-MB), which were reversed by treatment with AP. CFZ resulted in a significant increase in heart malondialdehyde (MDA) contents and decrease in cardiac glutathione (GSH) level and catalase (CAT) enzyme activity which were significantly reversed by treatment with AP. Induction of cardiotoxicity by CFZ significantly increased caspase-3 enzyme activity which were reversed by treatment with AP. RT-PCR analysis revealed an increased mRNA expression of NF-κB, ERK and JNK which were reversed by treatment with AP in cardiac tissues. Western blot analysis revealed an increased expression of caspase-3 and NF-κB p65 and a decrease expression of inhibitory kappa B-alpha (Iκbα) with CFZ, which were reversed by treatment with AP. In conclusion, apremilast showed protective effect against CFZ-induced cardiotoxicity.