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Middle Holocene cultures have been widely studied around the Eastern-Mediterranean basin in the last 30 years and past cultural activities have been commonly linked with regional climate changes. However, in many cases such linkage is equivocal, in part due to existing climatic evidence that has been derived from areas outside the distribution of ancient settlements, leading to uncertainty from complex spatial heterogeneity in both climate and demography. A few high-resolution well-dated paleoclimate records were recently established using speleothems in the Central and Eastern-Mediterranean basin, however, the scarcity of such records in the western part of the Mediterranean prevents us from correlating past climate evolutions across the basin and deciphering climate-culture relation at fine timescales. Here we report the first decadal-resolved Mid-Holocene climate proxy records from theWestern-Mediterranean basin based on the stable carbon and oxygen isotopes analyses of two U/Th dated stalagmites from the Gueldaman GLD1 Cave in Northern Algeria. Comparison of our records with those from Italy and Israel reveals synchronous (multi) centennial dry phases centered at ca. 5600, ca. 5200 and ca. 4200 yr BP across the Mediterranean basin. New calibrated radiocarbon dating constrains reasonably well the age of rich anthropogenic deposits (e.g., faunal remains, pottery, charcoal) excavated inside the cave, which allows the comparison between in situ evidence of human occupation and of climate change. This approach shows that the timing of a prolonged drought at ca. 4400-3800 yr BP blankets the onset of cave abandonment shortly after ca. 4403 cal yr BP, supporting the hypothesis that a climate anomaly may have played a role in this cultural disruption. [ABSTRACT FROM AUTHOR]

Middle Holocene cultures have been widely studied round the E-Mediterranean basin in the last 30 years and past cultural activities have been commonly linked with regional climate changes. However, in many cases such linkage is equivocal, in part due to existing climatic evidence that has been derived from areas outside the distribution of ancient settlements, leading to uncertainty from complex spatial heterogeneity in both climate and demography. A few high-resolution well-dated paleoclimate records were recently established using speleothems in the Central and E-Mediterranean basin, however, the scarcity of such records in the western part of the Mediterranean prevents us from correlating past climate evolutions across the basin and deciphering climate-culture relation at fine time scales. Here we report the first decadal-resolved Mid-Holocene climate proxy records from the W-Mediterranean basin based on the stable carbon and oxygen isotopes analyses of two U/Th dated stalagmites from the Gueldaman GLD1 Cave in N-Algeria. Comparison of our records with those from Italy and Israel reveals synchronous (multi) centennial dry phases centered at ca. 5600, ca. 5200 and ca. 4200 yrBP across the Mediterranean basin. New calibrated radiocarbon dating constrains reasonably well the age of rich anthropogenic deposits (e.g., faunal remains, pottery, charcoal) excavated inside the cave, which allows the comparison between in situ evidence of human occupation and of climate change. This approach shows that the timing of a prolonged drought at ca. 4400-3800 yrBP blankets the onset of cave abandonment shortly after ca. 4403 cal yrBP, supporting the hypothesis that a climate anomaly may have played a role in this cultural disruption. [ABSTRACT FROM AUTHOR]

Background: The constant development of microbial resistance to the traditional antimicrobial agents and the emergence of new infectious diseases justify the urgent need for new effective antimicrobial molecules. However, the irrational use of antibiotics increases microbial resistance dramatically and along with that the frequency of mortality associated with infections is higher. Therefore, to combat the antimicrobial resistance, the screening of compounds with novel chemical structures is essential. This study intended to determine the antimicrobial potential of Streptomyces GLD22 strain isolated from Algeria., Methods: The characterization of Streptomyces strain GLD22 was performed by physiological, biochemical and molecular tests. The antimicrobial activity was tested by the well diffusion method and the minimum inhibitory concentration value calculation were performed using broth micro dilution technique. The extracellular metabolites profiling was done using GC-MS., Results: Physiological, biochemical and phylogenetic analysis confirmed that the strain GLD22 showed maximum identity towards Streptomyces species. The extra cellular metabolites revealed their antimicrobial activity at 1 mg/ml for Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, whereas Staphylococcus aureus, Bacillus cereus and Bacillus subtilis documented 0.5, 1 and 1 mg/ml respectively. GC-MS analysis confirmed that 2-tert-butyl-4,6-bis(3,5-di-tert-butyl-4-hydroxybenzyl) phenol, Dibutyl phthalate and Cyclo(leucyloprolyl) were the major drug molecules present in the extract., Conclusion: The novel Streptomyces strain GLD22 recovered from the Gueldaman cave of Algeria showed better antimicrobial activity towards both Gram positive and Gram negative pathogens. Interestingly, the MIC values were comparable with the standard drug molecules. In addition, the identification of active metabolites present in the crude extracts was an advantage., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The pressures on honeybee (Apis mellifera) populations, resulting from threats by modern pesticides, parasites, predators and diseases, have raised awareness of the economic importance and critical role this insect plays in agricultural societies across the globe. However, the association of humans with A. mellifera predates post-industrial-revolution agriculture, as evidenced by the widespread presence of ancient Egyptian bee iconography dating to the Old Kingdom (approximately 2400 BC). There are also indications of Stone Age people harvesting bee products; for example, honey hunting is interpreted from rock art in a prehistoric Holocene context and a beeswax find in a pre-agriculturalist site. However, when and where the regular association of A. mellifera with agriculturalists emerged is unknown. One of the major products of A. mellifera is beeswax, which is composed of a complex suite of lipids including n-alkanes, n-alkanoic acids and fatty acyl wax esters. The composition is highly constant as it is determined genetically through the insect's biochemistry. Thus, the chemical 'fingerprint' of beeswax provides a reliable basis for detecting this commodity in organic residues preserved at archaeological sites, which we now use to trace the exploitation by humans of A. mellifera temporally and spatially. Here we present secure identifications of beeswax in lipid residues preserved in pottery vessels of Neolithic Old World farmers. The geographical range of bee product exploitation is traced in Neolithic Europe, the Near East and North Africa, providing the palaeoecological range of honeybees during prehistory. Temporally, we demonstrate that bee products were exploited continuously, and probably extensively in some regions, at least from the seventh millennium cal BC, likely fulfilling a variety of technological and cultural functions. The close association of A. mellifera with Neolithic farming communities dates to the early onset of agriculture and may provide evidence for the beginnings of a domestication process.

It is reported that reversible changes in the reflectivity of Bragg gratings can be induced by a change in the temperature of the grating (77 K < T < K). The changes have proved to be greater in highly doped Ge fibers than in standard fibers, whereas they could hardly be detected in hydrogenated fibers. The sign of the change for type I gratings was opposite that for type IIA gratings. The changes are likely due to a temperature-induced increase (or a decrease) in the amplitude of the refractive-index modulation. Possible mechanisms for these changes in modulation are discussed. Interestingly for the purpose of correcting data of isothermal accelerated aging experiments, a numerical relation that accounts for the temperature-induced changes in type I grating reflectivity is given.