SOUTHERN JOURNAL OF SCIENCES

It is investigated the effect of synthesized organic compounds of 6-hydroxy-2,2,4-trimethyl-1,2- dihydroquinoline, its derivatives, and hydrogenated analogs. These compounds affected the height of seedlings when they were used for pre-sowing seed treatment of the following ornamental plants: annual ornamental grass – scarlet sage (Salvia splendens) and woody plant – yellow rhododendron (Rhododendron luteum). Prior to the sprouting process, the seeds of Rh. luteum and S. splendens were soaked in water solutions of compounds with concentrations of 0.01%, 0.05%, and 0.1% for 18 hours. Dihydro- and tetrahydroquinolines with a concentration of 0.05% proved to be the most effective for both plants. For Rhododendron luteum, the compounds of 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline, its derivatives, and hydrogenated analogs with a concentration of 0.1% proved to be the most effective. Dihydroquinolines at concentrations of 0.05 and 0.1% proved to have the strongest effect when applied to the studied perennial woody plant (Rhododendron luteum). Dihydroquinoline at the concentration of 0.05% also proved to be effective when applied to the annual grass (Salvia splendens). For annual S. splendens, tetrahydroquinoline at concentrations of 0.01 and 0.05% appeared to be the most effective. The pre-sowing seed treatment of grass Salvia splendens and woody plant Rhododendron luteum with the studied compounds demonstrated that their effect on the height of the seedlings is species-specific. The pre-sowing seed treatment of Rh. luteum and S. splendens allows increasing the height of the seedlings by 3-61 % and 17-25 %, respectively. It is suggested using the compounds of 6-hydroxy-2,2,4- trimethyl-1,2-dihydroquinoline, its derivatives, and hydrogenated analogs as effective growth stimulators for ornamental grasses and woody plants.

Background: Infectious diseases are a global problem, the second human cause of death. Infectious diseases caused by pathogenic bacteria have been treated with a high degree of efficacy. However, even when the 20th century was considered the “golden age” of antibiotics, bacteria developed a different resistance mechanism to antibiotics. In 2017, the WHO issued an alert about 12 bacteria with an urgent need to develop new antibiotics. Aims: The aim of the present review is to analyze the current knowledge of the antibacterial activity of natural extract-based treatments against the pathogens listed by WHO. Methods: A systematic review of the literature in PubMed was performed to search for publications describing the use of natural extracts as antibiotics over bacteria. We focused on the Gram-Negative group. The exclusion criteria consisted of limiting papers on natural extracts tested over the bacteria culture related to eight selected bacteria, according to an alert issued by WHO in 2017, and seven plant extracts. Results: All the Gram-Negative bacteria listed in 2017 by WHO have been treated, with different degrees of advance, with some of the plant extracts and plant-based compounds reviewed. In general, the first approach is using inhibition disks applied over the bacterial biofilm in solid culture media. Discussion: While Salmonellae and P. aeruginosa have been extensively studied, over N. gonorrhoeae, A. baumannii have been tested with fewer natural extracts. Edible herbs are more often used, as well as artemisa and wine byproducts. In all cases, they are in the early stages of study, not being tested in patients at present. Conclusions: Plant extracts and plant-based compounds are effective as antibacterial, with minimal effects on the host cell. Furthermore, they are sustainable, environmentally friendly, and renewable.

Background: Scientific conferences play a vital role in knowledge exchange and collaboration across disciplines. Building on the success of its 2022 inaugural event, the Second Southern Science Conference (SSCON 2024) aimed to expand international scientific collaboration while addressing contemporary challenges in sustainability and research methodology. Aims: To evaluate the effectiveness of a hybrid conference format in facilitating global scientific collaboration and to showcase cutting-edge research across multiple disciplines, with particular emphasis on sustainability and technological innovation in Latin America. Methods: The conference implemented a hybrid format combining in-person and virtual attendance. Over three days, 38 lectures were presented by renowned researchers, covering key topics including materials science, environmental sustainability, chemical processes, and regional development. Participation metrics and collaboration patterns were analyzed to assess the conference's impact. Results: The conference achieved significant participation with 242 contributing authors from 13 countries across four continents. Notable research presentations included advances in laser surface modification techniques, geotechnology applications in biofuel production, sustainable silica synthesis from biomass, and green valorization of tropical seeds. The conference produced 66 approved papers, with most involving 2-5 collaborators. Discussion: The hybrid format proved effective in removing geographical barriers and promoting global engagement. The strong representation from Latin American institutions highlighted the region's growing influence in international scientific discourse. Key research presentations demonstrated innovative approaches to sustainability challenges, particularly in waste utilization and environmental technology. Conclusion: SSCON 2024 successfully evolved from its predecessor, demonstrating the effectiveness of hybrid conferencing in fostering international scientific collaboration. The conference established itself as a vital platform for knowledge exchange, particularly in sustainability and technological innovation, while identifying areas for future improvement such as extended submission timelines and permanent management structures.