Search for: All records

During the course of human evolution, lithic technology became a critical element of hominin foraging ecology and a contributor to feedback loops selecting for increasingly sophisticated tool use, cognition, and language. Here we review the first million years of technology, from 3.3 million years ago (Ma) to 2.3 Ma. This time interval includes the two oldest archaeological industries (the Lomekwian and the early Oldowan) known exclusively from Africa, which collectively overlap with four genera of hominins (human relatives and ancestors). These Early Stone Age (ESA) industries focused on the production and use of sharp edges for cutting, as well as the use of larger, sometimes unworked stones for pounding. We review our current understanding of these technologies, where they were found, how they were made, what they were used for, and the hominins that could have produced them, and consider them in the context of nonhuman primate archaeology. 

Rapid urbanization has prompted considerable interest in understanding which species thrive or fail in these novel environments. Because half of the human population resides in coastal areas, studies that explicitly examine urban tolerances among coastal species are needed. Here, we sought to explain variation in coastal bird tolerances to urban habitats with species life history, diet, nest, social, sensory and sexual selection traits using phylogenetically informed models and three urban-tolerance indexes. We found that nest site height was the strongest predictor, with species nesting in elevated locations exhibiting greater urban tolerance, probably due to reduced anthropogenic disturbances and risk of predation. Life-history traits, including larger clutch sizes and lower brood value, reflecting more lifetime breeding attempts, also predicted urban tolerance, suggesting that fast reproductive strategies buffer against urban-associated risks. Contrary to our prediction, species with altricial young displayed higher urban tolerance, potentially due to shorter incubation and fledging times. Collectively, our results suggest that many of the predictors related to urban tolerance in songbirds also predict tolerances among a broader swath of avian diversity. Such knowledge should help researchers forecast the composition of coastal, urban bird communities in the future and will inform efforts to conserve functionally diverse coastal ecosystems. 

The adaptive shift that favored stone tool–assisted behavior in hominins began by 3.3 million years ago. However, evidence from early archaeological sites indicates relatively short-distance stone transport dynamics similar to behaviors observed in nonhuman primates. Here we report selective raw material transport over longer distances than expected at least 2.6 million years ago. Hominins at Nyayanga, Kenya, manufactured Oldowan tools primarily from diverse nonlocal stones, pushing back the date for expanded raw material transport by over half a million years. Nonlocal cobbles were transported up to 13 kilometers for on-site reduction, resulting in assemblage patterns inconsistent with accumulations formed by repeated short-distance transport events. These findings demonstrate that early toolmakers moved stones over substantial distances, possibly in anticipation of food processing needs, representing the earliest archaeologically visible signal for the incorporation of lithic technology into landscape-scale foraging repertoires. 

Bacterial pathogens pose a major risk to human health, leading to tens of millions of deaths annually and significant global economic losses. While bacterial infections are typically treated with antibiotic regimens, there has been a rapid emergence of antimicrobial resistant (AMR) bacterial strains due to antibiotic overuse. Because of this, treatment of infections with traditional antimicrobials has become increasingly difficult, necessitating the development of innovative approaches for deeply understanding pathogen function. To combat issues presented by broad- spectrum antibiotics, the idea of narrow-spectrum antibiotics has been previously proposed and explored. Rather than interrupting universal bacterial cellular processes, narrow-spectrum antibiotics work by targeting specific functions or essential genes in certain species or subgroups of bacteria. Here, we generate a collection of genome-scale metabolic network reconstructions (GENREs) of pathogens through an automated computational pipeline. We used these GENREs to identify subgroups of pathogens that share unique metabolic phenotypes and determined that pathogen physiological niche plays a role in the development of unique metabolic function. For example, we identified several unique metabolic phenotypes specific to stomach pathogens. We identified essential genes unique to stomach pathogens in silico and a corresponding inhibitory compound for a uniquely essential gene. We then validated our in silico predictions with an in vitro microbial growth assay. We demonstrated that the inhibition of a uniquely essential gene,thyX, inhibited growth of stomach-specific pathogens exclusively, indicating possible physiological location-specific targeting. This pioneering computational approach could lead to the identification of unique metabolic signatures to inform future targeted, physiological location-specific, antimicrobial therapies, reducing the need for broad-spectrum antibiotics. 

The migratory movements undertaken by birds are among the most energetically demanding behaviours observed in nature. Mitochondria are the source of aerobic energy production on which migration depends, but a key component of mitochondrial function, mitochondrial remodelling, has not been investigated in the context of bird migration. We measured markers of mitochondrial remodelling in the skeletal muscles of the Gambel’s (migratory) and Nuttall’s (non-migratory) white-crowned sparrows within and outside migratory periods. Gambel’s were collected in (i) a non-migration period (baseline), (ii) preparation to depart for spring migration (pre-migration) and (iii) active autumn migration (mid-migration). Nuttall’s were collected at timepoints corresponding to baseline and mid-migration in Gambel’s. Across all sampling periods, we found that migratory birds had greater mitochondrial remodelling compared with non-migratory birds. Furthermore, birds from the migratory population also displayed flexibility, increasing several markers of mitochondrial remodelling (e.g. NRF1, OPA1 and Drp1) pre- and during migration. Further, the greater levels of mitochondrial remodelling and its upregulation during migration were specific to the pectoralis muscle used in flapping flight. Our study is the first to show that mitochondrial remodelling supports migration in Gambel’s white-crowned sparrows, indicating a highly specific and efficient phenotype supporting the increased energetic demands of migration. 

The maternal regulation of diapause is one type of phenotypic plasticity where the experience of the mother leads to changes in the phenotype of her offspring that impact how well-suited they will be to their future environment. Sarcophaga bullata females with a diapause history produce offspring that cannot enter diapause even if they are reared in a diapause inducing environment. Accumulating evidence suggests that microRNAs regulate diapause and, possibly, maternal regulation of diapause. We found significant differences in the abundances of several microRNAs (miR-125–5p, miR-124–3p, miR-31–5p, and miR-277–3p) in brains dissected from adult female S. bullata that had experienced diapause compared to females with no diapause history. We also found moderate differences in the mRNA expression of the circadian-clock related genes, clock, clockwork orange, and period. MiR-124–3p and miR-31–5p are part of a gene network that includes these circadian clock-related genes. Taken together our results suggest the maternal block of diapause in S. bullata is regulated, at least in part, by a network that includes microRNAs and the circadian clock. 

Abstract Small, spherical vesicles are a widely used chassis for the formation of model protocells and investigating the beginning of compartmentalized evolution. Various methods exist for their preparation, with one of the most common approaches being gentle hydration, where thin layers of lipids are hydrated with aqueous solutions and gently agitated to form vesicles. An important benefit to gentle hydration is that the method produces vesicles without introducing any organic contaminants, such as mineral oil, into the lipid bilayer. However, compared to other methods of liposome formation, gentle hydration is much less efficient at encapsulating aqueous cargo. Improving the encapsulation efficiency of gentle hydration would be of broad use for medicine, biotechnology, and protocell research. Here, we describe a method of sequentially hydrating lipid thin films to increase encapsulation efficiency. We demonstrate that sequential gentle hydration significantly improves encapsulation of water-soluble cargo compared to the traditional method, and that this improved efficiency is dependent on buffer composition. Similarly, we also demonstrate how this method can be used to increase concentrations of oleic acid, a fatty acid commonly used in origins of life research, to improve the formation of vesicles in aqueous buffer.