Hidden diversity: comparative functional morphology of humans and other species.

Gastrointestinal (GI) morphology plays an important role in nutrition, health, and epidemiology; yet limited data on GI variation have been collected since 1885. Here we demonstrate that students can collect reliable data sets on gut morphology; when they do, they reveal greater morphological variation for some structures in the GI tract than has been documented in the published literature. We discuss trait variability both within and among species, and the implications of that variability for evolution and epidemiology. Our results show that morphological variation in the GI tract is associated with each organ's role in food processing. For example, the length of many structures was found to vary significantly with feeding strategy. Within species, the variability illustrated by the coefficients of variation suggests that selective constraints may vary with function. Within humans, we detected significant Pearson correlations between the volume of the liver and the length of the appendix (t-value = 2.5278, df = 28, p = 0.0174, corr = 0.4311) and colon (t-value = 2.0991, df = 19, p = 0.0494, corr = 0.4339), as well as between the lengths of the small intestine and colon (t-value = 2.1699, df = 17, p = 0.0445, corr = 0.4657), which are arguably the most vital organs in the gut for nutrient absorption. Notably, intraspecific variation in the small intestine can be associated with life history traits. In humans, females demonstrated consistently and significantly longer small intestines than males (t-value15 = 2.245, p = 0.0403). This finding supports the female canalization hypothesis, specifically, increased female investment in the digestion and absorption of lipids.

Investigating the Timing and Extent of Juvenile and Fetal Bone Diagenesis in a Temperate Environment.

It is well understood that intrinsic factors of bone contribute to bone diagenesis, including bone porosity, crystallinity, and the ratio of organic to mineral components. However, histological analyses have largely been limited to adult bones, although with some exceptions. Considering that many of these properties are different between juvenile and adult bone, the purpose of this study is to investigate if these differences may result in increased degradation observed histologically in fetal and juvenile bone. Thirty-two fetal (n = 16) and juvenile (n = 16) Sus scrofa domesticus femora subject to different depositions over a period of two years were sectioned for histological observation. Degradation was scored using an adapted tunneling index. Results showed degradation related to microbial activity in both fetal and juvenile remains across depositions as early as three months. Buried juvenile remains consistently showed the greatest degradation over time, while the blanket fetal remains showed more minimal degradation. This is likely related to the buried remains' greater contact with surrounding soil and groundwater during deposition. Further, most of the degradation was seen in the subendosteal region, followed by the subperiosteal region, which may suggest the initial microbial attack is from endogenous sources.

Fungi associated with the potato taste defect in coffee beans from Rwanda.

BACKGROUND: Potato taste defect (PTD) of coffee is characterized by a raw potato like smell that leads to a lower quality taste in the brewed coffee, and harms the commercial value of some East African coffees. Although several causes for PTD have been proposed, none of them have been confirmed. Recently, high throughput sequencing techniques and bioinformatic analysis have shown great potential for identifying putative causal agents of plant diseases. Toward the goal of determining the cause of PTD, we examined raw coffee beans from Rwanda exhibiting varying PTD scores using an Illumina-based sequence analysis of the fungal rRNA ITS region. RESULTS: Six fungal amplicon sequence variants (ASVs) with high relative abundances correlated with coffee taste scores. Four of these ASVs exhibited negative correlations - Aspergillus versicolor, Penicillium cinnamopurpureum, Talaromyces radicus, and Thermomyces lanuginosus - indicating that they might be causing PTD. Two of these fungi exhibited positive correlations - Kazachstania humilis and Clavispora lusitaniae - indicating that they might be inhibiting organisms that cause PTD. CONCLUSIONS: This study addressed PTD causality from a new angle by examining fungi with high throughput sequencing. To our knowledge, this is the first study characterizing fungi associated with PTD, providing candidates for both causality and biocontrol.

Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts.

The purpose of this paper is to introduce a promising, novel method to aid in the assessment of bone quality in forensically relevant skeletal remains. BMD is an important component of bone's nutritional status and in skeletal remains of both juveniles and adults, and it can provide information about bone quality. For adults remains, it can provide information on pathological conditions or when bone insufficiency may have occurred. In juveniles, it provides a useful metric to elucidate cases of fatal starvation or neglect, which are generally difficult to identify. This paper provides a protocol for the anatomical orientation and analysis of skeletal remains for scanning via dual-energy X-ray absorptiometry (DXA). Three case studies are presented to illustrate when DXA scans can be informative to the forensic practitioner. The first case study presents an individual with observed longitudinal fractures in the weight bearing bones and DXA is used to assess bone insufficiency. BMD is found to be normal suggesting another etiology for the fracture pattern present. The second case study employed DXA to investigate suspected chronic malnutrition. The BMD results are consistent with results from long bone lengths and suggest the juvenile had suffered from chronic malnutrition. The final case study provides an example where fatal starvation in a fourteen-month infant is suspected, which supports autopsy findings of fatal starvation. DXA scans showed low bone mineral density for chronological age and is substantiated by traditional assessments of infant health. However, when dealing with skeletal remains taphonomic alterations should be considered before applying this method.

Decomposition of juvenile-sized remains: a macro- and microscopic perspective.

There is currently a dearth of research investigating the progression and rate of decomposition for juvenile remains. It is thought that juveniles and infants decompose at an increased rate relative to adults due simply to body mass and that skeletal preservation is commonly dependent on intrinsic levels of bone mineral density (BMD). This study investigates the environmental variables important in driving juvenile decomposition as well as examining if currently accepted methodology for quantifying adult decomposition can be applied to juvenile remains. Furthermore, histological analysis is undertaken to test the Histological Index (HI) as a semi-quantitative indicator of decomposition. Thirty-five Sus scrofa ranging between 1.8 and 22.7 kg were deposited to simulate body mass of human infant and juvenile remains. Pigs were deposited every season over two years in the southeastern US with five depositional types: bagged, blanket wrapped, and surface control foetal remains, surface, and buried juvenile remains. Remains were scored quantitatively throughout soft tissue decomposition. Following study completion and skeletonization, a femur was selected from each set of remains for histological analysis. Thick sections were assessed under standard brightfield light and scored using Oxford Histological Index (OHI). Results indicate that seasonal variation is an important factor to consider even when using a standardized time variable such as accumulated degree days (ADD), particularly variation in soil moisture. Soil moisture was a consistent significant variable in the mixed effects model. The pattern of decomposition using total body score (TBS) was similar to that observed by others prior to log transformation with a rapid incline early in decomposition with levelling off. The correlation between time in days, ADD, and TBS was not as strong as those previously reported (R 2 = 0.317 and 0.499, respectively) suggesting that TBS as it is currently formulated cannot be directly applied to juvenile remains. Finally, the OHI model performed moderately well, but was variable even within seasons across multiple years.

Flowers and Wild Megachilid Bees Share Microbes.

Transmission pathways have fundamental influence on microbial symbiont persistence and evolution. For example, the core gut microbiome of honey bees is transmitted socially and via hive surfaces, but some non-core bacteria associated with honey bees are also found on flowers, and these bacteria may therefore be transmitted indirectly between bees via flowers. Here, we test whether multiple flower and wild megachilid bee species share microbes, which would suggest that flowers may act as hubs of microbial transmission. We sampled the microbiomes of flowers (either bagged to exclude bees or open to allow bee visitation), adults, and larvae of seven megachilid bee species and their pollen provisions. We found a Lactobacillus operational taxonomic unit (OTU) in all samples but in the highest relative and absolute abundances in adult and larval bee guts and pollen provisions. The presence of the same bacterial types in open and bagged flowers, pollen provisions, and bees supports the hypothesis that flowers act as hubs of transmission of these bacteria between bees. The presence of bee-associated bacteria in flowers that have not been visited by bees suggests that these bacteria may also be transmitted to flowers via plant surfaces, the air, or minute insect vectors such as thrips. Phylogenetic analyses of nearly full-length 16S rRNA gene sequences indicated that the Lactobacillus OTU dominating in flower- and megachilid-associated microbiomes is monophyletic, and we propose the name Lactobacillus micheneri sp. nov. for this bacterium.

The Impact of Freezing on Bone Mineral Density: Implications for Forensic Research.

It is common for researchers using animal or human remains for scientific study to freeze samples prior to use. However, effects of freezing on bone macro- or microstructure are relatively unknown. The research objective of this study was to determine whether freezing could potentially bias experimental results by analyzing changes in bone mineral density (BMD) with the freezing of remains over time. Eight fetal pigs were scanned to determine their initial BMD before freezing. Three piglets underwent a freeze-thaw cycle to assess the effects of the freezing process. Four piglets were frozen and scanned weekly for 20 weeks to assess freezing over time. The overall average between the fresh initial scan and final frozen scan was significantly different (p < 0.001). Per contra, the final thawed BMD scans did not differ from the initial fresh scan (p = 0.418). Thus, completely thawed remains are recommended for experimental studies.

A geometric morphometric validation study of computed tomography-extracted craniofacial landmarks.

This study investigates the variation between craniofacial landmarks extracted from computed tomographic (CT) scans and those collected from direct digitization of dry skulls. Thirteen traditional craniofacial landmarks were obtained from each CT scan using the coordinate option in the software Aviso. These coordinates were then compared with the coordinates digitized directly from the dry skulls as 2 separate samples and individually. Similarities were found between the 2 coordinate samples, with the first principal component representing only 23.97% of the total variation associated with the data acquisition methods, and were found to be statistically significant (P = 0.0223). Differences were more prevalent along the midline landmarks. In contrast, the individual specimen comparisons exhibited the largest amount of variation within the symmetric landmarks with the bilateral landmarks that were more medially located in the CT sample, but no individual specimens were significantly different (eg, P = 0.9883) when comparing both data acquisition modalities. The bilateral coordinates were not found to be significantly different for either analysis (P = 0.4165). The significant differences found for the entire data set suggest that the combination of CT-extracted and digitized individuals needs to be further explored with respect to the reference frames and sample composition. However, the individual specimen comparison results of this study validate the utility of CT-extracted landmarks when used for putative identifications in a forensic setting and when clinically applied.