The probiotic potential of lactobacilli isolated from Nile tilapia (Oreochromis niloticus)’s intestine

The potential probiotic acid lactic bacteria isolated from Nile tilapia (Oreochromis niloticus)fs intestine was tested for fish farming. In our collection, 10 Lactobacillus strains were targeted to confront a series of antibiotics in order to draw their resistance profile, and to test their degree of inhibitory to four pathogenic bacteria, Staphylococcus aureus, Escherichia coli, Streptococcus sp. and Pseudomonas sp. The power of acidification and tolerance was tested. Overall, our results show that strains BLT31 and BLT21 are fully susceptible and resistance to the tested antibiotics. Strains BLT3, BLT20, BLT21 and BLT23 have a good antagonistic effect against pathogenic bacteria that cause the highest damage in aquaculture. For acid lactic production, strains BLT3, BLT26, BLT27, BLT28, and BLT31 are considered fast since Ģ pH . 4U in less than three hours. As for the resistance to pH and bile salts, two strains BLT3 and BLT31 showed significant power which gives them acceptable probiotic potential.Key words: Probiotics, antibiotics, aquaculture, the Nile Tilapia, inhibitory activities, lactobacilli

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa.

The progression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in Africa has so far been heterogeneous, and the full impact is not yet well understood. In this study, we describe the genomic epidemiology using a dataset of 8746 genomes from 33 African countries and two overseas territories. We show that the epidemics in most countries were initiated by importations predominantly from Europe, which diminished after the early introduction of international travel restrictions. As the pandemic progressed, ongoing transmission in many countries and increasing mobility led to the emergence and spread within the continent of many variants of concern and interest, such as B.1.351, B.1.525, A.23.1, and C.1.1. Although distorted by low sampling numbers and blind spots, the findings highlight that Africa must not be left behind in the global pandemic response, otherwise it could become a source for new variants

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Monitoring the biological effects of pollution on the Algerian West coast using mussels Mytilus galloprovincialis

The Algerian west coast is the prime recipient ofsev eral forms of pollution; hence, the necessity for an impact assessment of this coastal pollution using a suite ofr ecommended marine biomarkers, including lysosomal membrane stability in living cells by the Neutral Red Retention Time (NRRT) method, the evaluation ofmicron ucleus (MN) frequency, and the determination ofacet ylcholinesterase (AChE) activity in mussels Mytilus galloprovincialis, sampled from the large, polluted Oran Harbour (OH) and the Maˆarouf( Mrf) marine mussel farm between July 2005 and April 2006. The difference in the variations oft he annual physical parameters between OH and Mrfco rresponds to the influence ofthe domestic and industrial sewage discharged by the city ofO ran. The biological data ofthe mussels (condition index, protein content) recorded at both sites were related to their natural reproductive cycle. This indicated that intrinsic variation between the sites due to different mussel development phases was minimal. The variation in the AChE activity of some organs ofO H and Mrfm ussels, with minimal inhibition in July and a higher NRRT recorded in the granular haemocytes in the Mrfthan in the OH mussels during the autumn and spring, depends on the quality ofthe biotope and on generic stress factors. Moreover, the variation in MN frequency, in general reflecting a non-significant seasonal and spatial genotoxic effect ofthe contamination at the two sampling sites, requires further investigations regarding biotic and abiotic variations

Effet des granulats sulfurés sur les résistances mécanique et la durabilité des BHPF avec ajouts de laitier = Effect of sulfur aggregates on mechanical resistance and durability for SFRHPC with the addition of slag

The transformation of sulfides present in the aggregate to sulfates causes internal sulfate attack (ISA) by formation of secondary ettringite in the hardened concrete. This pathological ettringite crystallizes, the generated pressure is greater than the tensile strength of the concrete. It generates internal swelling and causes disorders that can severely damage the structures. Favors to their structural and economic performance, high performance concrete steel fiber (SFRHPC) are increasingly used in construction. Increase productivity and reduce construction time on site. They provide substantial weight savings, therefore it is possible to build with less formwork, less concrete to set up and fewer reinforcement than ordinary concrete. The purpose of this study is to determine the effect of sulfur present in the hornfels crushed aggregates, on the mechanical strength, durability, and the microstructure of SFRHPC with the addition of blast furnace slag. In ordinary concrete, the pyrite aggregates cause cracking by expansion when they are in wet land. In high performance concretes this phenomenon is greatly reduced or absent. This is the result of a very low porosity, reduced flow of moisture that cannot propagate to aggregate. And sulfide is stable and cannot be transformed into aggressive sulfat