Soft‐Bodied Fossils Are Not Simply Rotten Carcasses – Toward a Holistic Understanding of Exceptional Fossil Preservation

Exceptionally preserved fossils are the product of complex interplays of biological and geological processes including burial, autolysis and microbial decay, authigenic mineralization, diagenesis, metamorphism, and finally weathering and exhumation. Determining which tissues are preserved and how biases affect their preservation pathways is important for interpreting fossils in phylogenetic, ecological, and evolutionary frameworks. Although laboratory decay experiments reveal important aspects of fossilization, applying the results directly to the interpretation of exceptionally preserved fossils may overlook the impact of other key processes that remove or preserve morphological information. Investigations of fossils preserving non‐biomineralized tissues suggest that certain structures that are decay resistant (e.g., the notochord) are rarely preserved (even where carbonaceous components survive), and decay‐prone structures (e.g., nervous systems) can fossilize, albeit rarely. As we review here, decay resistance is an imperfect indicator of fossilization potential, and a suite of biological and geological processes account for the features preserved in exceptional fossils.     

Detection of early ischemic damage by analysis of mitochondrial function in skinned fibers

The skinned fibers technique was applied for studies of the effects of global acute ischemia (1 h at 37°C) and long time (15 h) hypothermic (4°C) preservation of isolated rat hearts under different conditions (immersion or low-flow perfusion) on mitochondrial function in the cells in vivo. Skinned fibers were obtained by using saponin for permeabilization of the sarcolemma in separated fiber bundles cut from left ventricle. The experimental protocol of the respiration rate determination included a cytochrome c test to check the intactness of the outer mitochondrial membrane. The apparent K_m for ADP and the effect of creatine on the mitochondrial activity were also evaluated in these permeabilized fibers, taken from different groups of hearts. The preservation of low-flow perfused hearts resulted only in a slight decrease of creatine (20 mM) stimulated respiration at 0.1 mM ADP. The fibers from ischemic hearts or from hearts preserved by immersion showed a decrease of the apparent K_m for ADP, and a complete loss of the stimulatory effect of creatine. In these fibers, we could observe that the outer mitochondrial membrane was damaged. In conclusion, the results of this study show that assessment of mitochondrial parameters sensitive to organelles swelling – intactness of outer membrane and functionally coupled creatine kinase reaction – are the most sensitive indicators of early hypoxic or ischemic damage to mitochondria. Their determination in biopsy samples could be used for evaluation of the efficiency of the cardiac protection in heart surgery. (Mol Cell Biochem 174: 79–85, 1997)     

Finding a Place for the Commonplace: Hurricane Katrina, Communities, and Preservation Law

The aftermath of Hurricane Katrina drew attention to commonplace landscape markers that create for a community a sense of place— that connection between people and places crucial to a sense of corporate and individual identity and heritage. There is a legal context for sense of place within extant federal preservation legislation. Nevertheless, many such markers with special meanings for residents have been overlooked in federal documentation, the cornerstone of which is the National Register of Historic Places. Grassroots efforts and national media coverage have helped forge a niche for sense of place within the recovery plans and policy emerging in the affected region. However, it is unclear whether this will carry over into practice. In terms of long-term policy shifts, remedying the shortcomings highlighted by Katrina may require changes to the National Historic Preservation Act and its associated guidelines and regulations, or it may entail a new approach altogether.     

Creatine-loading preserves intestinal barrier function during organ preservation

We have developed a novel, intraluminal preservation solution that is tailored to the metabolic requirements of the intestine. This organ-specific solution addresses many of the problems associated with low temperature organ storage including energy, oxidative and osmotic stresses. However, conservation of energy levels remains one of the most difficult obstacles to overcome due to the inherent sensitivity of the mucosa to ischemia. Creatine-loading has become a popular and scientifically proven method of augmenting energy reserves in athletes performing anaerobic burst work activities. We hypothesized that if we could develop a method that was able to augment cellular energy levels, the structure and function of the mucosa would be more effectively preserved. The purpose of this study was to determine if creatine-loading is a feasible and effective strategy for preserving the intestine.Our data indicate that creatine loading has significant impact on energy levels during storage with corresponding improvements in mucosal structure and function. Both of our rodent models, a) continuous perfusion for 4 h and b) a single flush with our intraluminal preservation solution supplemented with 50 mM creatine, demonstrated significant improvements in creatine phosphate, ATP, Energy Charge and ATP/AMP following cold storage (P < 0.05). Notably, after 10 h creatine phosphate was 324% greater in Creatine-treated tissues compared to Controls (P < 0.05). Preferential utilization of glutathione in the Creatine group was effective at controlling oxidative injury after 10 h storage (P < 0.05). Improvements in barrier function and electrophysiology with creatine-treatment reflected superior mucosal integrity after 10 h storage; Permeability and Transepithelial resistance measurements remained at fresh tissue values. This was in stark contrast to Control tissues in which permeability rose to >300% of fresh tissue values (P < 0.005) and transepithelial resistance dropped by 95% (P < 0.005). After 10 h storage, Park's grading of histologic injury reflected extensive villus denudation (grade 4) in control tissues compared to healthy tissue (grade 0) in the Creatine group. This study demonstrates that a strategy of creatine supplementation of our intraluminal preservation solution facilitates the preservation of the intestinal mucosa during storage.     

Change in dysphagia and laryngeal function after radical radiotherapy in laryngo pharyngeal malignancies — a prospective observational study

BackgroundIntensity modulated radiotherapy (IMRT) has the perceived advantage of function preservation by reduction of toxicities in the treatment of laryngo-pharyngeal malignancies. The aim of the study was to assess changes in dysphagia from baseline (i.e. prior to start of treatment) at three and six months post treatment in patients with laryngo-pharyngeal malignancies treated with radical radiotherapy ± chemotherapy. Functional assessment of other structures involved in swallowing was also studied.Materials and methods40 patients were sampled consecutively. 33 were available for final analysis. Dysphagia, laryngeal edema, xerostomia and voice of patients were assessed at baseline and at three and six months after treatment. Radiation was delivered with simultaneous integrated boost (SIB) using volumetric modulated radiation therapy (VMAT). Concurrent chemotherapy was three weekly cisplatin 100 mg/m².ResultsProportion of patients with dysphagia rose significantly from 45.5% before the start of treatment to 57.6% at three months and 60.6% at six months post treatment (p = 0.019). 67% patients received chemotherapy and addition of chemotherapy had a significant correlation with dysphagia (p = 0.05, r = −0.336). Severity of dysphagia at three and six months correlated significantly with the mean dose received by the superior constrictors (p = 0.003, r = 0.508 and p = 0.024, r = 0.391) and oral cavity (p = 0.001, r = 0.558 and p = 0.003, r = 0.501). There was a significant worsening in laryngeal edema at three and six months post treatment (p < 0.01) when compared to the pre-treatment examination findings with 60.6% of patients having grade two edema at six months. Significant fall in the mean spoken fundamental frequency from baseline was seen at 6 months (p = 0.04), mean fall was 21.3 Hz (95% CI: 1.5–41 Hz) with significant increase in roughness of voice post treatment (p = 0.01).ConclusionThere was progressive worsening in dysphagia, laryngeal edema and voice in laryngo-pharyngeal malignancies post radical radiotherapy ± chemotherapy.     

Comparative experimental taphonomy of eight marine arthropods indicates distinct differences in preservation potential

Global biodiversity patterns in deep time can only be understood fully when the relative preservation potential of each clade is known. The relative preservation potential of marine arthropod clades, a diverse and ecologically important component of modern and past ecosystems, is poorly known. We tackled this issue by carrying out a 205‐day long comprehensive, comparative, taphonomic experiment in a laboratory by scoring up to ten taphonomic characters for multiple specimens of seven crustacean and one chelicerate species (two true crabs, one shrimp, one lobster, one hermit crab, one stomatopod, one barnacle and one horseshoe crab). Although the results are preliminary because we used a single experimental setup and algal growth partially hampered observations, some parts of hermit crabs, stomatopods, swimming crabs and barnacles decayed slowly relative to other parts, implying differential preservation potentials within species, largely consistent with the fossil record of these groups. An inferred parasitic isopod, manifested by a bopyriform swelling within a hermit crab carapace, decayed relatively fast. We found limited variation in the decay rate between conspecifics, and we did not observe size‐related trends in decay rate. Conversely, substantial differences in the decay rate between species were seen after c. 50 days, with shrimps and stomatopods decaying fastest, suggesting a relatively low preservation potential, whereas the lobster, calico crabs, horseshoe crabs and barnacles showed relatively slow decay rates, suggesting a higher preservation potential. These results are supported by two modern and fossil record‐based preservation potential metrics that are significantly correlated to decay rate ranks. Furthermore, we speculate that stemward slippage may not be ubiquitous in marine arthropods. Our results imply that diversity studies of true crabs, lobsters, horseshoe crabs and barnacles are more likely to yield patterns that are closer to their true biodiversity patterns than those for stomatopods, shrimps and hermit crabs.     

木醋液对鲜切麝香百合的保鲜效应

以木醋液为保鲜液,对鲜切麝香百合进行瓶插保鲜的结果表明：木醋液能增强麝香百合吸收保鲜液的能力,延长其盛花期和瓶插寿命,增强过氧化氢酶（CAT）活性,降低麝香百合瓶插期间的丙二醛（MDA）含量和过氧化物酶（POD）活性,延缓其衰老,其中以3．4g&#183;L^-1木醋液对鲜切百合的保鲜效应最好。