Analisis Fenolik dan Daya Hambat Daun Binahong (Anredera Cordifolia (ten.) Steenis) terhadap Bakteri Eschericia Coli dan Staphylococcus Aureus

Abstrak: Penelitian ini bertujuan untuk menganalisis kandungan fenolik dan mengetahui daya hambat ekstrak daun binahong (Anredera cordifolia (Ten.) Steenis) terhadap bakteriEschericia coli dan Staphylococcus aureus. Ekstraksi daun daun binahong menggunakan pelarut etanol, dan etil asetat. Ekstrak yang diperoleh dianalisis menggunakan spektrofotometer UV-Vis untuk mengetahui kandungan fenolik dan daya hambatnya. Diperoleh kadar fenolik ekstrak etanol sebesar 28,43 mg GAE/g ekstrak, ekstrak etil asetat sebesar 26,47 mg GAE/g ekstrak. Konsentrasi hambat minimum (KHM) ekstrak etanol dan etil asetat terhadap E. coli masing-masing sebesar 8,5%, dan 7,5%.Konsentrasi hambat minimum (KHM) ekstrak etanol dan etil asetat terhadap S. aureus masing masing sebesar 8%, dan 9,5%

A review on antimicrobial packaging from biodegradable polymer composites

The development of antimicrobial packaging has been growing rapidly due to an increase in awareness and demands for sustainable active packaging that could preserve the quality and prolong the shelf life of foods and products. The addition of highly efficient antibacterial nanoparticles, antifungals, and antioxidants to biodegradable and environmentally friendly green polymers has become a significant advancement trend for the packaging evolution. Impregnation of antimicrobial agents into the packaging film is essential for impeding or destroying the pathogenic microorganisms causing food illness and deterioration. Higher safety and quality as well as an extended shelf life of sustainable active packaging desired by the industry are further enhanced by applying the different types of antimicrobial packaging systems. Antimicrobial packaging not only can offer a wide range of advantages, but also preserves the environment through usage of renewable and biodegradable polymers instead of common synthetic polymers, thus reducing plastic pollution generated by humankind. This review intended to provide a summary of current trends and applications of antimicrobial, biodegradable films in the packaging industry as well as the innovation of nanotechnology to increase efficiency of novel, bio-based packaging systems

Le détournement d’ubiquitine ligases à culine 4 par la protéine PB2 des virus influenza A conduit à son ubiquitination non protéolytique

Le système ubiquitine protéasome (UPS), régule un grand nombre de processus cellulaires, en catalysant l’ubiquitination des protéines. Les virus exploitent l'UPS pour favoriser l’infection, et échapper à la réponse immunitaire de l'hôte. Nous nous sommes concentrés sur l'interaction entre la protéine PB2 de la polymérase du virus de l'influenza A (IAV) et des enzymes E3 ubiquitine ligases à cullin 4 (CRL4), en particulier les facteurs les protéines DDB1, DCAF11 et DCAF12L1 les composant. Nous avons montré que deux CRL4s sont des régulateurs positifs de l'infection virale, et qu’ils catalysent l’ubiquitination de la protéine PB2 pendant l'infection. Cette ubiquitination, constituée par des chaînes poly-ubiquitine K29, n’induit pas la dégradation de PB2. Les CRL4s peuvent interagir avec PB2 lorsqu’elle est engagée dans le complexe de polymérase virale, mais n’affectent ni la transcription ni la réplication des segments viraux. Les CRL4 catalysent l'ubiquitination de différentes lysines sur PB2, qui pourraient supporter des fonctions distinctes de PB2. Nos travaux fournissent la première caractérisation d'une PTM non protéolytique de PB2, qui semble être nécessaire à l’infection optimale par les IAV. De plus, en utilisant la purification par affinité suivie d'une spectrométrie de masse (AP/MS), nous avons identifié des ensembles distincts de facteurs cellulaires se liant aux CRL4s pendant l'infection. Ces résultats pointent vers une modification du protéome cellulaire ciblé par ces CRL4 E3 ligases pro-virales pendant l'infection par les IAV.The ubiquitin proteasome system regulates numerous cell processes, through ubiquitination of proteins. A vast interplay between viral proteins and host UPS exists, to promote successful infection and escape host’s immune response. We focused on the interaction between influenza A virus (IAV) polymerase protein PB2 and factors of the multi-components E3 ubiquitin ligase complex based on cullin 4 (CRL4) namely DDB1, DCAF11 and DCAF12L1 (designated as CRL4s). We found that PB2 undergoes a non-proteolytic ubiquitination, catalyzed by two CRL4s during infection. These CRL4s are positive regulators of viral infection, required for an optimal virions production and normal progression of viral cycle. We identified K29-linked ubiquitin chains as the main components of the non-proteolytic PB2 ubiquitination mediated by the CRL4s, thereby providing the first example of the\u2028role of this atypical ubiquitin linkage in the regulation of a viral infection. Although CRL4 E3 ligases are able to bind to PB2 when engaged in the viral polymerase complex, they did not affect the transcription and replication of viral segments. The two CRL4 ligases catalyzed the ubiquitination of different lysines on PB2, which might support distinct functions of PB2. Our work provides the first characterization of a non-proteolytic PTM of PB2, which might be essential for the successful outcome of an IAV infection. Furthermore, using affinity-purification followed by mass spectrometry (AP/MS) we identified distinct sets of cellular factors binding to the CRL4s during IAV infection. These results point towards the rewiring of cellular proteome targeted by the pro-viral CRL4 E3 ligases during IAV infection

A GENETIC ALGORITHM BASED BUS SCHEDULING MODEL FOR TRANSIT NETWORK

Abstract: In this paper we present an optimization model for bus scheduling. This model constitutes one of the three major components of a solution approach for solving the transit network design problem. The problem of scheduling can be defined in the following general terms: Given the origin destination matrix for the bus trips for design period, the underlying bus network characterized by the overlapping routes, how optimally to allocate the buses among these routes? The bus scheduling problem is solved in two levels. In the first level, minimum frequency of buses required on each route, with the guarantee of load feasibility, is determined by considering each route individually. In the second level, the fleet size of first level is taken as upper bound and fleet size is again minimized by considering all routes together and using GAs. The model is applied to a real network, and results are presented

Nonproteolytic K29-Linked Ubiquitination of the PB2 Replication Protein of Influenza A Viruses by Proviral Cullin 4-Based E3 Ligases

International audienceThe multifunctional nature of viral proteins is essentially driven by posttranslational modifications (PTMs) and is key for the successful outcome of infection. For influenza A viruses (IAVs), a composite pattern of PTMs regulates the activity of viral proteins. However, almost none are known that target the PB2 replication protein, except for inducing its degradation. We show here that PB2 undergoes a nonproteolytic ubiquitination during infection. We identified E3 ubiquitin ligases catalyzing this ubiquitination as two multicomponent RING-E3 ligases based on cullin 4 (CRL4s), which are both contributing to the levels of ubiquitinated forms of PB2 in infected cells. The CRL4 E3 ligase activity is required for the normal progression of the viral cycle and for maximal virion production, indicating that the CRL4s mediate a ubiquitin signaling that promotes infection. The CRL4s are recruiting PB2 through an unconventional bimodal interaction with both the DDB1 adaptor and DCAF substrate receptors. While able to bind to PB2 when engaged in the viral polymerase complex, the CRL4 factors do not alter transcription and replication of the viral segments during infection. CRL4 ligases catalyze different patterns of lysine ubiquitination on PB2. Recombinant viruses mutated in the targeted lysines showed attenuated viral production, suggesting that CRL4-mediated ubiquitination of PB2 contributes to IAV infection. We identified K29-linked ubiquitin chains as main components of the nonproteolytic PB2 ubiquitination mediated by the CRL4s, providing the first example of the role of this atypical ubiquitin linkage in the regulation of a viral infection.IMPORTANCE Successful infection by influenza A virus, a pathogen of major public health importance, involves fine regulation of the multiple functions of the viral proteins, which often relies on post-translational modifications (PTMs). The PB2 protein of influenza A viruses is essential for viral replication and a key determinant of host range. While PTMs of PB2 inducing its degradation have been identified, here we show that PB2 undergoes a regulating PTM signaling detected during infection, based on an atypical K29-linked ubiquitination and mediated by two multicomponent E3 ubiquitin ligases. Recombinant viruses impaired for CRL4-mediated ubiquitination are attenuated, indicating that ubiquitination of PB2 is necessary for an optimal influenza A virus infection. The CRL4 E3 ligases are required for normal viral cycle progression and for maximal virion production. Consequently, they represent potential candidate host factors for antiviral targets

Influenza A virus co-opts ERI1 exonuclease bound to histone mRNA to promote viral transcription

International audienceCellular exonucleases involved in the processes that regulate RNA stability and quality control have been shown to restrict or to promote the multiplication cycle of numerous RNA viruses. Influenza A viruses are major human pathogens that are responsible for seasonal epidemics, but the interplay between viral proteins and cellular exonucleases has never been specifically studied. Here, using a stringent interactomics screening strategy and an siRNA-silencing approach, we identified eight cellular factors among a set of 75 cellular proteins carrying exo(ribo)nuclease activities or involved in RNA decay processes that support influenza A virus multiplication. We show that the exoribonuclease ERI1 interacts with the PB2, PB1 and NP components of the viral ribonucleoproteins and is required for viral mRNA transcription. More specifically, we demonstrate that the protein-protein interaction is RNA dependent and that both the RNA binding and exonuclease activities of ERI1 are required to promote influenza A virus transcription. Finally, we provide evidence that during infection, the SLBP protein and histone mRNAs co-purify with vRNPs alongside ERI1, indicating that ERI1 is most probably recruited when it is present in the histone pre-mRNA processing complex in the nucleus

The transcriptional landscape of Venezuelan equine encephalitis virus (TC-83) infection.

Venezuelan Equine Encephalitis Virus (VEEV) is a major biothreat agent that naturally causes outbreaks in humans and horses particularly in tropical areas of the western hemisphere, for which no antiviral therapy is currently available. The host response to VEEV and the cellular factors this alphavirus hijacks to support its effective replication or evade cellular immune responses are largely uncharacterized. We have previously demonstrated tremendous cell-to-cell heterogeneity in viral RNA (vRNA) and cellular transcript levels during flaviviral infection using a novel virus-inclusive single-cell RNA-Seq approach. Here, we used this unbiased, genome-wide approach to simultaneously profile the host transcriptome and vRNA in thousands of single cells during infection of human astrocytes with the live-attenuated vaccine strain of VEEV (TC-83). Host transcription was profoundly suppressed, yet "superproducer cells" with extremely high vRNA abundance emerged during the first viral life cycle and demonstrated an altered transcriptome relative to both uninfected cells and cells with high vRNA abundance harvested at later time points. Additionally, cells with increased structural-to-nonstructural transcript ratio exhibited upregulation of intracellular membrane trafficking genes at later time points. Loss- and gain-of-function experiments confirmed pro- and antiviral activities in both vaccine and virulent VEEV infections among the products of transcripts that positively or negatively correlated with vRNA abundance, respectively. Lastly, comparison with single cell transcriptomic data from other viruses highlighted common and unique pathways perturbed by infection across evolutionary scales. This study provides a high-resolution characterization of the VEEV (TC-83)-host interplay, identifies candidate targets for antivirals, and establishes a comparative single-cell approach to study the evolution of virus-host interactions

The cargo adaptor protein CLINT1 is phosphorylated by the Numb-associated kinase BIKE and mediates dengue virus infection

International audienceThe signaling pathways and cellular functions regulated by the four Numb-associated kinases (NAKs) are largely unknown. We previously reported that AAK1 and GAK control intracellular trafficking of RNA viruses, and recently revealed a requirement for BIKE in early and late stages of dengue virus (DENV) infection. However, the downstream targets phosphorylated by BIKE in this process have not yet been identified. Here, to identify BIKE substrates, we conducted a barcode fusion genetics-yeast two-hybrid screen and retrieved publicly available data generated via affinity-purification mass spectrometry. We subsequently validated 19 of 47 putative BIKE interactors using mammalian cell-based protein-protein interaction assays. We found that CLINT1, a cargo-specific adaptor implicated in bidirectional Golgi-to-endosome trafficking, emerged as a predominant hit in both screens. Our experiments indicated that BIKE catalyzes phosphorylation of a threonine 294 (T294) CLINT1 residue both in vitro and in cell culture. Our findings revealed that CLINT1 phosphorylation mediates its binding to the DENV nonstructural 3 protein and subsequently promotes DENV assembly and egress. In addition, using live-cell imaging we revealed that CLINT1 cotraffics with DENV particles and is involved in mediating BIKE's role in DENV infection. Finally, our data suggest that additional cellular BIKE interactors implicated in the host immune and stress responses and the ubiquitin proteasome system might also be candidate phosphorylation substrates of BIKE. In conclusion, these findings reveal cellular substrates and pathways regulated by the understudied NAK enzyme BIKE, a mechanism for CLINT1 regulation, and control of DENV infection via BIKE signaling, with potential implications for cell biology, virology, and host-targeted antiviral design

Anticancer pan-ErbB inhibitors reduce inflammation and tissue injury and exert broad-spectrum antiviral effects.

Targeting host factors exploited by multiple viruses could offer broad-spectrum solutions for pandemic preparedness. Seventeen candidates targeting diverse functions emerged in a screen of 4,413 compounds for SARS-CoV-2 inhibitors. We demonstrated that lapatinib and other approved inhibitors of the ErbB family of receptor tyrosine kinases suppress replication of SARS-CoV-2, Venezuelan equine encephalitis virus (VEEV), and other emerging viruses with a high barrier to resistance. Lapatinib suppressed SARS-CoV-2 entry and later stages of the viral life cycle and showed synergistic effect with the direct-acting antiviral nirmatrelvir. We discovered that ErbB1, ErbB2, and ErbB4 bind SARS-CoV-2 S1 protein and regulate viral and ACE2 internalization, and they are required for VEEV infection. In human lung organoids, lapatinib protected from SARS-CoV-2-induced activation of ErbB-regulated pathways implicated in non-infectious lung injury, proinflammatory cytokine production, and epithelial barrier injury. Lapatinib suppressed VEEV replication, cytokine production, and disruption of blood-brain barrier integrity in microfluidics-based human neurovascular units, and reduced mortality in a lethal infection murine model. We validated lapatinib-mediated inhibition of ErbB activity as an important mechanism of antiviral action. These findings reveal regulation of viral replication, inflammation, and tissue injury via ErbBs and establish a proof of principle for a repurposed, ErbB-targeted approach to combat emerging viruses