Myoid fibrils in epithelial cells: studies of intestine, biliary and pancreatic pathways, trachea, bronchi, and testis.

Cytoplasmic filaments have been studied extensively by electron microscopy, but the histochemical nature of such fibrils in non-keratinizing epithelia has not been systematically investigated. During studies of early arterial lesions we observed structures with the staining properties of myosins in epithelial cells of various organs. The configurational staining, polarization and fluorescence microscopic properties of these myoid structures were compared with those of myofibrils in smooth muscle and classical myoepithelial cells. The following structures showed the characteristics of myofibrils: the terminal web in columnar epithelial cells of intestine, trachea, bronchi, bile ducts, pancreatic ducts and ductus epididymidis, the pericanalicular layer of bile and pancreatic canaliculi, fibers in the caudal tube of spermatids and the flagella of spermatozoa. Cilia, e.g. of respiratory epithelium, tonofibrils in squamous epithelium and nerve axons did not react. These studies indicate significant histochemical differences between cytoplasmic filaments. Different types of intracellular fibrils can be found in the same cell, e.g. in respiratory epithelium.     

Competition between Cellana tramoserica (Sowerby) (gastropoda) and Patiriella exigua (Lamarck) (asteroidea), and their influence on algal standing stocks

Caging experiments were undertaken in the field to test if competition occurs within and between the limpet Cellana tramoserica (Sowerby) and the starfish Patiriella exigua (Lamarck). Both species suffer from intraspecific competition, even at natural densities, and increased density reduces body weight and survival in Cellana tramoserica and growth rate in Patiriella exigua. Cellana tramoserica depresses the growth of Patiriella exigua, while the starfish unexpectedly seems beneficial to Cellana tramoserica, increasing its body weight. The difference in these effects may be due to the divergent methods of feeding used by the two species. C. tramoserica digs into the substratum and removes most available microflora, while Patiriella exigua everts its stomach onto the rock face and can only remove superficial or loosely attached microflora and detritus, and leaves a mucous web which may supplement the diet of Cellana tramoserica. Even at low densities C. tramoserica can completely prevent macroalgae from developing, while Patiriella exigua is unable to do so, although it shows the rate of development. Macroalgae grew in all the cages which contained only P. exigua, but in spite of this the starfish still suffered from intraspecific competition, probably because they cannot feed on macroalgae. Cellana tramoserica also competes by interference, and on contact with Patiriella exigua it extends its mantle and pallial tentacles, both of which may release mucus. P. exigua retreats from Cellana tramoserica, and those parts of its body that have been touched by the limpet may temporarily be immobilised and become wrinkled up. It is suggested that this interference behaviour by C. tramoserica is derived from a similar but more intense reaction that it has to invertebrate predators. Patiriella exigua lacks a pelagic larva and does not have a refuge outside the range of Cellana tramoserica. Other factors must thus be sought to explain the continued coexistence of Patiriella exigua with Cellana tramoserica. It is suggested that although C. tramoserica has a competitive effect on Patiriella exigua, it (and other grazers) may be necessary for P. exigua, preventing macroalgal growth and maintaining a surface suitable for P. exigua to feed on.     

African Herald snakes,Crotaphopeltis, show population structure for a widespread generalist but deep genetic divergence for forest specialists

The African colubrid snake genus Crotaphopeltis currently comprises six species and occurs throughout sub-Saharan Africa. The most widespread of these, Crotaphopeltis hotamboeia, inhabits most biomes, aside from rainforest and hyper-arid regions, and its catholic niche has presumably facilitated substantial gene flow. Despite this, the geographical range is large enough that ecological or physical barriers might exist, facilitating allopatric diversification. In contrast, most of the other species are habitat specialists with limited distributions (e.g., Crotaphopeltis tornieri) and would be expected to show strong genetic structure. We therefore examined species boundaries within Crotaphopeltis in a phylogenetic context using five markers (16S, cyt b, ND4, c-mos, and RAG-1) for four of the six species. Species delimitation methods included two coalescent-based and one barcoding approach. Widespread geographical sampling of C. hotamboeia allowed examination of genetic structuring across its range. The species status of Crotaphopeltis barotseensis, C. degeni, and C. hotamboeia was confirmed, whereas the Afromontane species C. tornieri comprised two candidate species. Crotaphopeltis hotamboeia did not show cryptic speciation, although its phylogeographic structure corresponded with the spatiotemporal pattern of the African savanna. Our results show how the heterogeneous African environment could influence genetic partitioning of habitat specialist and generalist species at broad geographical scales.     

Augmented Dried versus Cryopreserved Amniotic Membrane as an Ocular Surface Dressing

Purpose

Dried amniotic membrane (AM) can be a useful therapeutic adjunct in ophthalmic surgery and possesses logistical advantages over cryopreserved AM. Differences in preservation techniques can significantly influence the biochemical composition and physical properties of AM, potentially affecting clinical efficacy. This study was established to investigate the biochemical and structural effects of drying AM in the absence and presence of saccharide lyoprotectants and its biocompatibility compared to cryopreserved material.

Methods

AM was cryopreserved or dried with and without pre-treatment with trehalose or raffinose and the antioxidant epigallocatechin (EGCG). Structural and visual comparisons were assessed using electron microscopy. Localisation, expression and release of AM biological factors were determined using immunoassays and immunofluorescence. The biocompatibility of the AM preparations co-cultured with corneal epithelial cell (CEC) or keratocyte monolayers were assessed using cell proliferation, cytotoxicity, apoptosis and migration assays.

Results

Drying devitalised AM epithelium, but less than cryopreservation and cellular damage was reduced in dried AM pre-treated with trehalose or raffinose. Dried AM alone, and with trehalose or raffinose showed greater factor retention efficiencies and bioavailability compared to cryopreserved AM and demonstrated a more sustained biochemical factor time release in vitro. Cellular health assays showed that dried AM with trehalose or raffinose are compatible and superior substrates compared to cryopreserved AM for primary CEC expansion, with increased proliferation and reduced LDH and caspase-3 levels. This concept was supported by improved wound healing in an immortalised human CEC line (hiCEC) co-cultured with dried and trehalose or raffinose membranes, compared to cryopreserved and fresh AM.

Conclusions

Our modified preservation process and our resultant optimised dried AM has enhanced structural properties and biochemical stability and is a superior substrate to conventional cryopreserved AM. In addition this product is stable and easily transportable allowing it to be globally wide reaching for use in clinical and military sectors.     

Seasonal and Geographic Variation of Southern Blue Whale Subspecies in the Indian Ocean

Understanding the seasonal movements and distribution patterns of migratory species over ocean basin scales is vital for appropriate conservation and management measures. However, assessing populations over remote regions is challenging, particularly if they are rare. Blue whales (Balaenoptera musculus spp) are an endangered species found in the Southern and Indian Oceans. Here two recognized subspecies of blue whales and, based on passive acoustic monitoring, four “acoustic populations” occur. Three of these are pygmy blue whale (B.m. brevicauda) populations while the fourth is the Antarctic blue whale (B.m. intermedia). Past whaling catches have dramatically reduced their numbers but recent acoustic recordings show that these oceans are still important habitat for blue whales. Presently little is known about the seasonal movements and degree of overlap of these four populations, particularly in the central Indian Ocean. We examined the geographic and seasonal occurrence of different blue whale acoustic populations using one year of passive acoustic recording from three sites located at different latitudes in the Indian Ocean. The vocalizations of the different blue whale subspecies and acoustic populations were recorded seasonally in different regions. For some call types and locations, there was spatial and temporal overlap, particularly between Antarctic and different pygmy blue whale acoustic populations. Except on the southernmost hydrophone, all three pygmy blue whale acoustic populations were found at different sites or during different seasons, which further suggests that these populations are generally geographically distinct. This unusual blue whale diversity in sub-Antarctic and sub-tropical waters indicates the importance of the area for blue whales in these former whaling grounds.     

Early–Middle Holocene vegetation history, climate change and human activities at Lago Riane (Ligurian Apennines, NW Italy)

The radiocarbon-dated palaeoecological study of Lago Riane (Ligurian Apennines, NW Italy) presented here forms part of a wider investigation into the relationships between Holocene vegetation succession, climate change and human activities in the northern Apennines. The record of vegetation history from Lago Riane indicates that, since the end of the last glaciation, climate change and prehistoric human activities, combined with several local factors, have strongly influenced the pattern and timing of natural vegetation succession. The pollen record indicates an important change in vegetation cover at Lago Riane at ~8500–8200 cal. years b.p., coincident with a well-known period of rapid climate change. At ~6100 cal. years b.p., Fagus woodland colonised Lago Riane during a period of climate change and expansion of Late Neolithic human activities in the upland zone of Liguria. A marked decline in Abies woodland, and the expansion of Fagus woodland, at ~4700 cal. years b.p., coincided with further archaeological evidence for pastoralism in the mountains of Liguria during the Copper Age. At ~3900–3600 cal. years b.p. (Early to Middle Bronze Age transition), a temporary expansion of woodland at Lago Riane has been provisionally attributed to a decline in human pressure on the environment during a period of short-term climate change.     

Smart is the new sexy: female mountain chickadees increase reproductive investment when mated to males with better spatial cognition

Understanding the evolution of inter and intraspecific variation in cognitive abilities is one of the main goals in cognitive ecology. In scatter‐caching species, spatial memory is critical for the recovery of food caches and overwinter survival, but its effects on reproduction are less clear. Better spatial cognition may improve pre‐breeding condition allowing for earlier reproduction. Alternatively, when mated to males with better spatial memory, females may be able to invest more in reproduction which may allow increased offspring survival and hence higher fitness. Using wild food‐caching mountain chickadees, we found that when environmental conditions were favourable for breeding, females mated to males with better spatial cognition laid larger clutches and fledged larger broods than females mated to males with worse cognitive performance. Our results support the hypothesis that females may increase their reproductive investment to gain indirect, genetic benefits when mated to high‐quality males with better spatial cognitive abilities.     

How does exercise intensity and type affect equine distal tarsal subchondral bone thickness?

Adaptation of osteochondral tissues is based on the strains experienced during exercise at each location within the joint. Different exercise intensities and types may induce particular site-specific strains, influencing osteochondral adaptation and potentially predisposing to injury. Our hypotheses were that patterns of equine distal tarsal subchondral bone (SCB) thickness relate to the type and intensity of exercise, and that high-intensity exercise leads to site-specific increases in thickness. SCB thickness was measured at defined dorsal and plantar locations on magnetic resonance images of cadaver tarsi collected from horses with a history of low [general purpose (n=20) and horse walker (n=6)] or high [elite competition (n=12), race training (n=15), and treadmill training (n=4)] exercise intensity. SCB thickness was compared between sites within each exercise group and between exercise groups. SCB thickness in elite competition and race training, but not treadmill training, was greater than low-intensity exercise. For general purpose horses, lateral SCB thickness was greater than medial throughout. Horse walker exercise led to relatively thicker lateral and medial SCB compared with the midline. Elite competition was associated with increased SCB thickness of the proximal small tarsal bones medially and the distal bones laterally. For race training and treadmill training, there were minimal differences between sites overall, although the lateral aspect was greater than medial, and medial greater than midline at a few sites for race training. In conclusion, different types of high-intensity exercise were associated with different patterns of SCB thickness across the joints from medial to lateral and proximal to distal, indicating that both exercise intensity and type of exercise affect the SCB response at any particular site within the equine distal tarsal joints.