Preservation of fossils in the Šárka Formation (Darriwilian, Czech Republic)

The Šárka Formation is a well-known, fossiliferous Ordovician deposit in Bohemia. It has been targeted by fossil collectors since the 19th century due to the excellent preservation of many fossils. As a result, mainly well-preserved and interesting specimens have been deposited in collections. Many fragments, typical fossil accumulations but also complete specimens belonging to common taxa, have been ignored because they were considered poorly preserved compared to others. That is why some palaeoecological and taphonomical aspects of faunas are insufficiently represented in the existing collections. The Šárka Formation is early to middle Darriwilian in age and reflects an overall deepening of the Prague Basin, an Early Palaeozoic peri-Gondwanan basin, with a relic of its fill situated roughly between PlzeÅ and Prague as a part of the Teplá-Barrandian unit in Central Bohemia, Czech Republic. The Šárka Formation is typified by the prevalence of grey to dark grey shales that are 50 m thick in the south-western part of the basin and up to 300 m in the north-eastern part of it. Locally, these shales contain levels with predominantly siliceous nodules. Both, shales and nodules, are fossiliferous, but fossils demonstrate different modes of preservation, primarily resulting from different degrees of compaction accompanied by other processes such as the dissolution of shells. The highly diverse fauna in the formation is dominated by trilobites. Rhynchonelliformean brachiopods, bivalves, gastropods, cephalopods, ostracods, hyoliths, and echinoderms are very abundant; other groups such as conulariids, monoplacophorans, rostroconchs, machaeridans, and graptolites are less frequent. The fossils occur as isolated specimens, in clusters, or in larger concentrations of transported shells on the bedding planes. Fossils, the shells of which were originally composed of several parts (trilobite exoskeletons, bivalve molluscs, crustaceans, hyoliths, etc.), are often disarticulated. Disarticulated parts of skeletons are mostly complete, with a low degree of fragmentation. This is the prevailing mode of preservation, but some locali­ties yielded also abundant complete trilobites. In general, allochthonous material transported to short distances prevails in the Šárka Formation. Preservation in shales. The fossils in shales are variably compacted. Specimens of the groups producing organic protective structures, such as graptolites, range from predominantly flattened to relief when pyritized. The material of phosphatic shells (phyllocarid crustaceans, linguliformean brachiopods, conulariids) is usually preserved, primarily deformed depending on its solidity, and secondarily slightly flattened. Calcareous shells are often dissolved and the fossils cracked. Although primary cracking also occurs, many shells are collapsed indicating their deformation due to the sediment compaction before dissolution of a shell during late diagenesis. Preservation in nodules. Nodules are of early diagenetic origin and fossils in them are pre­served in full relief because they were protected from compaction. All deformations of fossils, such as cracking, can be considered primary, i.e. formed before the nodule formation. Only phosphatic shells occur in the nodules, organic and calcareous shells are not preserved with only minor exceptions. Thus, the dominating preservation mode of fossils in the nodules is as in­ternal and external moulds or only external moulds with a cavity inside. However, there is one special type of internal mould, which has been known for a long time but ignored because of its âworseâ preservation. This is related to many articulated brachiopods and bivalves but often also to some parts of trilobites, hyoliths and gastropods. It is formed by a porous spongiform material, sometimes forming irregular structures resembling the crumble. This taphonomic feature, unique for the nodules, represents a specific type of preservation. It can fully or partly fill in the cavities inside the closed two-valved shells, some enrolled trilobites, adapical parts of hyolith conchs, and gastropod shells but also glabellae, axes, or other parts of trilobites. This preservation is there­fore common in enclosed spaces of shells where the presence of organic substances, especially remains of tissues can be expected to occur even after their burial in the sediment. Subsequent decay of tissues in an open geochemical system, such as inside a muddy substrate that is a precursor of shales, would not be traced under normal conditions due to the migration of matters. The nodules were apparently of a very early diagenetic origin and their formation ceased the migration system of decaying tissue substances. The products of these processes remained in situ and fossilized in the form of the âtaphonomic crumbleâ, which has a considerable potential for several research directions

Ordovician conulariid monospecific assemblages (Czech Republic, Morocco)

A recently discovered locality of the Katian age near Erfoud (Morocco) supports an assumption that at least some conulariids lived preferably in monospecific associations. Thousands of skeletons belonging to Archaeoconularia consobrina (Barrande, 1867) were documented in an extensive accumulation within a 20 cm thick calcareous sandstone bed containing also rounded intraclasts of fine-grained sediments. The specimens are well exposed on the top surface of the bed due to weathering. The specimens have the same prevailing orientation throughout the entire bed. The preservation and distribution patterns of these conulariids suggest a parautochthonous origin of the accumulation that was likely deposited after a single, high water-energy event, such as a storm or turbidite flow. The same taphonomic situation was recently described for Anaconularia anomala (Barrande, 1867) from a Sandbian site in the Czech Republic and for Archaeoconularia cf. consobrina (Barrande, 1867) in a different Sandbian site in Bohemia, Czech Republic. Thus, the monospecific conulariid assemblages with abundant specimens seem not to be exceptional. Such mass occurrences of conulariids are similar in (1) alignment of specimens along the pre­vailing current direction, (2) limited content of other faunal elements, and (3) the presence of intraclasts and the sandstone matrix. These taxa are interpreted as originally inhabiting an offshore environment below the storm wave base, with erected skeletons firmly attached to the sandy bottom at some calm places, or more probably deeply anchored in sand with the apical part (similar mode of life has recently been shown in fan mussels, which are often accompanied by algae forming sea meadows). During a single catastrophic event, conulariid skeletons were first broken off. This resulted in prevalence of the rounded schott ending in the apical region of the specimens. The apertural endings, including lappets, were destroyed during rapid transport prior to final de­position as aligned monospecific mass accumulations. It is worth noting that some localities, especially those in Morocco, yielded mass accumulations, with tests densely covered by diverse epibionts like brachiopods and edrioasteroids, while others are typified by undisturbed skeletons without attached epizoans or traces of attachment scars. All these taphonomic and palaeoecological aspects, as well as association with mass occurrences of algae, are subject to further study

Plant-Derived Bioactive Lipids Impacts Glucose Homeostasis and Energy Metabolism in Mice

There is a crucial need to identify and test sustainable alternatives to fish oil as a means to supplement dietary omega (n-3) fatty acids which have demonstrated health benefits to humans with metabolic syndrome and its associated diseases. Echium oil has a high content of the n-3 fatty acid stearidonic acid (SDA), a precursor of the bioactive lipids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) found in fatty cold-water fish, with known or possible functions to improve metabolism and delay the onset of or prevent diabetes. To characterize the effects of dietary Echium oil (EO) vs. fish oil (FO), the oils were formulated into either a low-fat (10% kcal; LF) or high fat (60% kcal; HF) diabetogenic diet and fed to male C57BL/6 Tac mice for 12 weeks. Compared to the low-fat or high-fat controls without the supplementation of EO or FO, EO and FO diets had no effect on blood glucose concentrations or plasma insulin levels throughout the study. The EO-enriched HF diet improved glucose tolerance by week 12 compared to the HF-CON (p\u3c0.05) and HF-FO (p\u3c0.1) groups. EO supplementation reduced visceral fat weight without affecting body mass, promoted a metabolically favorable high polyunsaturated fatty acid (PUFA) to saturated fatty acid (SFA) ratio in adipose and muscle tissues compared to the HF-CON and HF-FO diet groups, and led to higher tissue EPA and DHA concentrations compared to both LF and HF CON (p\u3c0.1). Tissue EPA and DHA in EO were not as high as the concentrations found in mice fed the FO diets for both HF and LF. In conclusion, EO-supplemented diets in mice appear to have distinct effects from FO diets that may be exploited in future strategies to curtail metabolic disorders

Influence of periparturient and postpartum diets on rumen methanogen communities in three breeds of primiparous dairy cows

Background: Enteric methane from rumen methanogens is responsible for 25.9 % of total methane emissions in the United States. Rumen methanogens also contribute to decreased animal feed efficiency. For methane mitigation strategies to be successful, it is important to establish which factors influence the rumen methanogen community and rumen volatile fatty acids (VFA). In the present study, we used next-generation sequencing to determine if dairy breed and/or days in milk (DIM) (high-fiber periparturient versus high-starch postpartum diets) affect the rumen environment and methanogen community of primiparous Holstein, Jersey, and Holstein-Jersey crossbreeds. Results: When the 16S rRNA gene sequences were processed and assigned to operational taxonomic units (OTU), a core methanogen community was identified, consisting of Methanobrevibacter (Mbr.) smithii, Mbr. thaueri, Mbr. ruminantium, and Mbr. millerae. The 16S rRNA gene sequence reads clustered at 3 DIM, but not by breed. At 3 DIM, the mean % abundance of Mbr. thaueri was lower in Jerseys (26.9 %) and higher in Holsteins (30.7 %) and Holstein-Jersey crossbreeds (30.3 %) (P < 0.001). The molar concentrations of total VFA were higher at 3 DIM than at 93, 183, and 273 DIM, whereas the molar proportions of propionate were increased at 3 and 93 DIM, relative to 183 and 273 DIM. Rumen methanogen densities, distributions of the Mbr. species, and VFA molar proportions did not differ by breed. Conclusions: The data from the present study suggest that a core methanogen community is present among dairy breeds, through out a lactation. Furthermore, the methanogen communities were more influenced by DIM and the breed by DIM interactions than breed differences.The author's would like to acknowledge the USDA Hatch Grant (VT-H01801) and the UVM Dairy Center of Excellence as funding sources for animals and laboratory supplies. Furthermore, the Agriculture and Food Research Initiative Competitive Grant no. 2014-67016-21791 from the USDA National Institute of Food and Agriculture supported the VFA and feed analyses. We would like to thank Dr. Benoit St-Pierre of South Dakota State University for assistance with bioinformatics and Kurt Cotanch of the William H. Miner Institute for assistance with VFA analyses. We would also like to thank the Paul Miller Research Farm staff (Matt Boudette, Scott Shumway, Doug Watkin) for their on-farm maintenance and assistance. Lastly, we would like to thank Columbia University undergraduate student, Ryan C. Noyes, and the UVM undergraduate students (Pamela Bay, Katherine Boucher, Dylan Devino, Michael Eldredge, Samantha Frawley, Emma Hurley, Anne Kaufman, Danielle Semick, Mallory Sullivan, Sarah Zeger) who helped with calving, sampling, and milking.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Subway into the Ordovician (Prague Basin, Czech Republic)

In the Late Ordovician, the Prague Basin was located at the high-latitude northwestern shelf of Gondwana. This period was characterised by profound environmental changes and ended by one of the most severe mass extinctions, which was caused by climatic changes. Although the end-Ordovician extinction is closely related to the Hirnantian glaciation, biodiversity started to decrease already in the late Katian. Decrease in temperatures and sea level drop are the main factors that affected these biodiversity changes. During the last years, construction of the new subway line D in Prague has provided a unique opportunity to study different aspects of the Upper Ordovician and Silurian of the Prague Basin. These tunnels have provided detailed information about the succession of fossil assemblages, facies variability and actual thicknesses of the upper Katian and Hirnantian formations (upper part of the Bohdalec, and entire Králův Dvůr and Kosov formations) in this part of the basin. Our study is based on material and data from several sites. We studied drill cores from vertical boreholes drilled from the surface and also horizontal boreholes drilled from the tunnel faces. The richest material came from an interim storage of excavated material near pitheads. In total, almost 700 m of sections in the tunnels were investigated. As the preliminary geo­logical exploration was carried out by various companies in connection with subway construction, intensive excavation and mining took place in several locations at the same time, and the frequency of our research activities and site visits were limited. Therefore, our palae­ontological and stratigraphical research was focused mainly on the Bohdalec Formation (upper Katian). The succession is, however, tectonised, apparently incomplete, and repetition of some parts cannot be excluded. The actual thickness of the investigated part of the Bohdalec Formation excavated so far is slightly less than 140 m (December 2022). The unit is dominated by fine-grained siliciclastics (dark grey shales and siltstones), except for the Michle Facies in the uppermost part of the Bohdalec Formation. This facies consists of calcareous sandstones alternating with siltstones and thin shaly interbeds. The section is regarded to be deposited in an offshore setting below the storm wave base. The Bohdalec Formation in the studied section is fossiliferous, and the abundance of fossils and composition of their associations are variable. Some subsections are typified by reduced fossil content. However, we also recorded several stratigraphical intervals (a few metres in thickness) with distinctly enriched fossil assemblages, notably with echinoderms, bryozoans, cnidarians, planktic graptolites, and sessile dendroid graptolites that are extremely rare anywhere else. Deposits of these specific intervals accumulated during gradual slowdown periods during the subsidence of the Prague Basin, which resulted in a decrease in the sedimentation rate and were followed by uplift, causing local shallowing. Also, global events, such as climatic and sea level fluctuations, influenced these changes of fauna and facies

Fetal and neonatal exposure to trans fatty acids impacts on susceptibility to atherosclerosis in apolipoprotein E*3 Leiden mice

Nutrition during pregnancy can impact on the susceptibility of the offspring to cardiovascular disease. Postnatal consumption of trans fatty acids (TFA), associated with partially hydrogenated vegetable oil (PHVO), increases the risk of atherosclerosis, while evidence for those trans fatty acids associated with ruminant-derived dairy and meat remain equivocal. Here, we investigate the impact of maternal consumption of dietary PHVO (P) and ruminant milk fat (R) on the development of atherosclerosis in their offspring, using the transgenic apoE*3 Leiden mouse. Dams were fed either chow (C) or one of three high fat diets: a diet reflecting the saturated fatty acid content of a ‘Western’ diet (W) or one enriched with either P or R. Diets were fed during either pregnancy alone or pregnancy and lactation. Weaned offspring were then transferred to an atherogenic diet for twelve weeks. Atherosclerosis was assessed as lipid staining in cross-sections of the aorta. There was a significant effect of maternal diet during pregnancy on development of atherosclerosis (p=0.013) in the offspring with those born of mothers fed R or P during pregnancy displaying smaller lesions that those fed C or W. This was not associated with changes in total or lipoprotein cholesterol. Continuing to feed P during lactation increased atherosclerosis compared to that seen in offspring of dams fed P only during pregnancy (p<0.001). No such effect was seen in those from mothers fed R (p=0.596) or W (p=901). We conclude that dietary TFA have differing effects on cardiovascular risk at different stages of the lifecycle

Alteration of rumen bacteria and protozoa through grazing regime as a tool to enhance the bioactive fatty acid content of bovine milk

Rumen microorganisms are the origin of many bioactive fatty acids (FA) found in ruminant-derived food products. Differences in plant leaf anatomy and chemical composition between cool- and warm-season pastures may alter rumen microorganisms, potentially enhancing the quantity/profile of bioactive FA available for incorporation into milk. The objective of this study was to identify rumen bacteria and protozoa and their cellular FA when cows grazed a warm-season annual, pearl millet (PM), in comparison to a diverse cool-season pasture (CSP). Individual rumen digesta samples were obtained from five Holstein cows in a repeated measures design with 28-day periods. The treatment sequence was PM, CSP, then PM. Microbial DNA was extracted from rumen digesta and sequence reads were produced with Illumina MiSeq. Fatty acids (FA) were identified in rumen bacteria and protozoa using gas-liquid chromatography/mass spectroscopy. Microbial communities shifted in response to grazing regime. Bacteria of the phylum Bacteroidetes were more abundant during PM than CSP (P \u3c 0.05), while protozoa of the genus Eudiplodinium were more abundant during CSP than PM (P \u3c 0.05). Microbial cellular FA profiles differed between treatments. Bacteria and protozoa from cows grazing CSP contained more n-3 FA (P \u3c 0.001) and vaccenic acid (P \u3c 0.01), but lower proportions of branched-chain FA (P \u3c 0.05). Microbial FA correlated with microbial taxa and levels of vaccenic acid, rumenic acid, and a-linolenic acid in milk. In conclusion, grazing regime can potentially be used to alter microbial communities shifting the FA profile of microbial cells, and subsequently, alter the milk FA profile

A Test between Plant and Fish Oil Sources: The Potential Benefits of Diet Enhanced with Omega-3 Fatty Acids

Skeletal muscle mediates 70-80% of glucose uptake. When the skeletal muscle’s capability to absorb glucose is reduced, the individual becomes insulin resistant and develops, if unabated, diabetes. Here we performed a high fat feeding study on inbred diet-induced obesity in C57BL/6 (B6) mice over the course of 12 weeks, in which we compared the well-established effects of omega-3 fatty acid (n-3) rich fish oil (FO) versus the poorly understood effects of balanced n-3 and omega-6 fatty acid (n-6) rich plant derived Echium oil (EO). Although there were little differences in HFEO or HFFO supplemented groups compared to the high fat control group with respect to blood glucose or plasma insulin concentrations, the Echium oil-enriched diet improved glucose tolerance by 12 weeks. Skeletal muscle was examined for diet-specific changes in insulin sensitivity, growth and survival signaling, and anti-inflammatory activity. We found that the n-3 supplemented high fat diet-fed mice, and especially the HFEO group, showed enhanced Akt1 activity, as well as increased GSK-3β phosphorylation and inactivation in the HFEO group, suggesting increased insulin signaling and glycogen synthesis. Although skeletal muscle PPARγ levels were not different among the high fat diet groups, BiP, a marker of ER stress, had a trend of being reduced in the HFEO group. Thus, the improved glucose tolerance of Echium oil-supplemented high fat diet-fed mice were due to changes in skeletal muscle physiology resulting in enhanced insulin sensitivity and reduced ER stress

Leukoencephalopathy after prophylactic whole-brain irradiation with or without hippocampal sparing: a longitudinal magnetic resonance imaging analysis

PURPOSE Neurocognitive changes are well described after prophylactic or therapeutic whole-brain radiotherapy (WBRT) and have been reported as early as 3 months after radiotherapy (RT). Therefore, WBRT with protection of the hippocampal region (hippocampal avoidance, HA) has been proposed to preserve neurocognition. Our aim was to compare the risk of leukoencephalopathy after prophylactic cranial irradiation (PCI) with or without HA. METHODS Patients with small-cell lung cancer who received either lateral-opposed field PCI (non-HA-PCI; n = 9) or hippocampus avoidance PCI (HA-PCI; n = 9) with available magnetic resonance imaging (MRI) follow-up were identified and age matched. Pre-therapeutic and follow-up MRI after RT was analysed for leukoencephalopathy based on the Fazekas score. Bilateral cortical and subcortical brain structures were segmented and analysed for alterations in dosimetric parameters and volumes. RESULTS There was no significant difference of Fazekas scores between groups at baseline. Fazekas score differed in post-treatment with a median of 1 in the HA-PCI group and 2 in the non-HA-PCI group (p = 0.007). Significant increase of Fazekas score over time after RT was observed for HA-PCI patients (p = 0.001) but not for non-HA-PCI patients. Dmax (highest radiation dose) and brain volume receiving doses >25Gy were higher in HA-PCI patients. There were no significant volumetric differences for segmented brain structures between groups. CONCLUSION Radiological changes are more prominent after HA-PCI than after non-HA-PCI. Although no standardised neurocognitive testing was performed, the significantly increased Fazekas scores after HA-PCI are expected to interfere with neurocognitive function. Prospective long-term neurocognitive studies are warranted before HA-PCI is implemented in routine clinical practice

Fetal and neonatal exposure to trans fatty acids impacts on susceptibility to atherosclerosis in apolipoprotein E*3 Leiden mice

Nutrition during pregnancy can impact on the susceptibility of the offspring to cardiovascular disease. Postnatal consumption of trans fatty acids (TFA), associated with partially hydrogenated vegetable oil (PHVO), increases the risk of atherosclerosis, while evidence for those trans fatty acids associated with ruminant-derived dairy and meat remain equivocal. Here, we investigate the impact of maternal consumption of dietary PHVO (P) and ruminant milk fat (R) on the development of atherosclerosis in their offspring, using the transgenic apoE*3 Leiden mouse. Dams were fed either chow (C) or one of three high fat diets: a diet reflecting the saturated fatty acid content of a ‘Western’ diet (W) or one enriched with either P or R. Diets were fed during either pregnancy alone or pregnancy and lactation. Weaned offspring were then transferred to an atherogenic diet for twelve weeks. Atherosclerosis was assessed as lipid staining in cross-sections of the aorta. There was a significant effect of maternal diet during pregnancy on development of atherosclerosis (p=0.013) in the offspring with those born of mothers fed R or P during pregnancy displaying smaller lesions that those fed C or W. This was not associated with changes in total or lipoprotein cholesterol. Continuing to feed P during lactation increased atherosclerosis compared to that seen in offspring of dams fed P only during pregnancy (