Biology subjects

Sliwa, A.

Publications and source records attributed to Sliwa, A..

3 recordsLinked to original sources

bioRxiv2026

Dog-assisted scat sampling reveals genetic diversity, structure, and relatedness in black-footed cats (Felis nigripes)

Advances in molecular techniques for non-invasive genetic sampling have strengthened wildlife genetics, enabling researchers to study elusive and difficult-to-study species with minimal disturbance, and conservation detection dogs can greatly increase sample numbers and the area covered. However, this combination is rarely used in Africa and has perhaps never been applied to a small carnivore on the continent. Here we use dog-assisted scat surveys to carry out the first fine-scale population genetic study of the black-footed cat (Felis nigripes), Africa's smallest and most range-restricted endemic felid, and a threatened species for which conventional survey methods are largely ineffective. Using 130 successfully genotyped scat samples (nine microsatellite loci) from two populations about 650 km apart, we identified 65 individuals and assessed genetic diversity and fine-scale relatedness to explore aspects of dispersal and reproductive ecology. Both populations exhibited similar observed heterozygosity (Ho = 0.67-0.69) and allelic richness, with no heterozygote deficit (FIS = -0.02 to -0.08). Differentiation between the southern Namibia and central South Africa sites was low but detectable (FST = 0.03-0.05). We used pairwise relatedness and candidate pedigree results to explore hypotheses about sex-specific relatedness patterns. Female-female dyads were more related than male-male dyads at the shortest distance class (0-2 km), a pattern compatible with female philopatry. There were more half-sibling than full-sibling assignments and uneven representation of candidate fathers, which may indicate polygamy and reproductive skew. These results provide baseline genetic data for a Vulnerable species and show that this approach is feasible for Africa's small, elusive carnivores, whose dispersal, mating systems and population structure remain largely unknown. Broader spatial and temporal sampling could help assess population connectivity and reveal how threats and changing land use impact genetic diversity and structure.

ecology↗

bioRxiv2026

Genetic Diversity and Population Structure of the Black-Footed Cat: Insights into Felis's Deadliest Predator

BackgroundBlack-footed cats (Felis nigripes) are one of Africas least studied felines. The population dynamics and demographic history of this solitary species have not been well-described. Reports of ongoing decline of present-day populations resulted in the IUCN Red List categorizing the species as vulnerable to extinction. As populations decline and become isolated from each other, they become susceptible to strong genetic drift and inbreeding, which can lead to the accumulation of deleterious alleles and increased sextinction risk. However, the IUCN cited data deficiencies across the species range as a limitation in this categorization for black-footed cats. In cases where ecological surveys are lacking, range-wide population genomic surveys can improve our understanding of population dynamics. ResultsIn the first genomic study of free-roaming individuals, we sequenced whole genomes of black-footed cats (N=44) from across their distribution. To do so, we incorporated whole genome sequences generated from both modern biological samples and century-old museum specimens. We assembled a highly contiguous reference genome using a combination of PacBio HiFi data and publicly available Hi-C data and investigated the demographic history, population structure, and genetic diversity of wild black-footed cats. We found evidence of historical effective population sizes of [~]11,500 individuals, which is lower than estimates reported in other felid species. Consistent with modest historical population sizes, we found that present-day genome-wide diversity was low ({pi} {approx} 0.0004). However, despite low genetic diversity, we find that black-footed cat genomes do not harbor long runs of homozygosity. Simulation results indicate that low present-day genetic diversity may simply result from modest historical population size. However, other analyses point to evidence of a population contraction in the last 50 generations, which could contribute to future genomic erosion. We also compared genomic variation in populations across the range to evaluate patterns of population structure, finding evidence of higher genetic similarity between individuals in closer geographic proximity. ConclusionOverall, these results provide range-wide information about the demographic history and present-day genetic diversity of an understudied species. Together with analyses of population structure, we speculate that there may be greater connectivity between populations of black-footed cats than previously assumed. Our study underscores the utility of genomic data in providing insights into population dynamics for better conservation management.

evolutionary biology↗

bioRxiv2023

Mycelium-bound lipases of psychrophilic and mesophilic fungi as biocatalysts for biodiesel synthesis

In this study, biocatalysts in the form of mycelium-bound lipases of psychrotrophic and mesophilic fungi were screened for their ability to synthesize fatty acid methyl (FAME) and ethyl esters (FAEE). It has been shown that the hydrolytic activity of biocatalysts is not accompanied by their biodiesel synthetic activity. Preliminary studies showed for the first time, that the FTIR technique can be used to predict synthetic activity. The highest correlation between the intensity of the bands and synthetic activity, negative and positive, respectively, was observed for two neighboring bands at 1745 cm-1 (R = -0.73) and 1699 cm-1 (R = 0.68). The psychrotrophic strain Penicillium sp. 59, isolated from the soil of the Arctic tundra (Spitsbergen), has been shown for the first time as an efficient whole-cell biocatalyst for fatty acid ethyl ester synthesis and is stable in organic solvents. Mathematical optimization of biosynthesis was also performed using RSM. A molar canola oil conversion value of 83.3% into FAEE was obtained at 24.2 {degrees}C in n-hexane using 12.5% of used canola oil and 5.3% of the fungal biocatalyst within 6 h. Dry mycelium of Penicillium sp. 59 is a promising new biocatalyst for large-scale biosynthesis of biodiesel, given its low-cost production, high activity at room temperature, no need to mix reactions, and reusability in a minimum of six cycles.

bioengineering↗