Experimental studies on microbial bioerosion at Lee Stocking Island, Bahamas and One Tree Island, Great Barrier Reef, Australia: implications for paleoecological reconstructions

Different kinds of experimental calcareous substrates were exposed at Lee Stocking Island (Bahamas) and One Tree Island (Great Barrier Reef, Australia) to study which endolithic bacteria, algae and fungi contribute to bioerosion and what their bioerosion rates are. The sites at Lee Stocking Island were several leeward shallow water and several windward shallow and deep-water positions (from the Acropora palmata reef at 2 m down to 275 m depth). At One Tree Island, the experiments were conducted in patch reefs treated with P and N to study the influence of mineral nutrients on bioerosion. The exposure periods ranged from 1 week to 2 years. The micritic carbonate substrates exposed on Lee Stocking Island contained 6 genera with 15 species of cyanobacteria, green and red algae, and different kinds of microendolithic heterotrophs. The mean values of bioerosion rates measured between 1 to 2 g/m²/y at 275 m and 520 g/m²/y at one of the leeward sites. The composition of the endolithic community and the bioerosion rates changed over time. At One Tree Island, shell pieces of Tridacna were used as substrate exposed for 5 months to endolith activity. Five genera and 6 species of cyanobacteria, green and red algae and different kinds of heterotrophic microendoliths were found with bioerosion rates of 20-30 g/m²/y. There are differences in abundance of taxa between Lee Stocking Island and One Tree Island. The introduction of nutrients had no apparent impact on the microborer community. Controlling factors for the distribution and abundance of microborers are mainly light, but also the kind of substrate and, possibly, the biogeographic position. The results support the paleoecological importance of microendoliths.     

Temperature dependence of vesicular dynamics at excitatory synapses of rat hippocampus

How vesicular dynamics parameters depend on temperature and how temperature affects the parameter change during prolonged high frequency stimulation was determined by fitting a model of vesicular storage and release to the amplitudes of the excitatory post-synaptic currents (EPSC) recorded from CA1 neurons in rat hippocampal slices. The temperature ranged from low (13 °C) to higher and more physiological temperature (34 °C). Fitting the model of vesicular storage and release to the EPSC amplitudes during a single pair of brief high–low frequency stimulation trains yields the estimates of all parameters of the vesicular dynamics, and with good precision. Both fractional release and replenishment rate decrease as the temperature rises. Change of the underlying ‘basic’ parameters (release coupling, replenishment coupling and readily releasable pool size), which the model-fitting also yields is complex. The replenishment coupling between the readily releasable pool (RRP) and resting pool increases with temperature (which renders the replenishment rate higher), but this is more than counterbalanced by greater RRP size (which renders the replenishment rate lower). Finally, during long, high frequency patterned stimulation that leads to significant synaptic depression, the replenishment rate decreases markedly and rapidly at low temperatures (<22 °C), but at high temperatures (>28 °C) the replenishment rate rises with stimulation, making synapses better able to maintain synaptic efficacy.     

Is replenishment of the readily releasable pool associated with vesicular movement?

At the excitatory synapse of rat hippocampus the short-term synaptic depression observed during long high-frequency stimulation is associated with slower replenishment of the readily-releasable pool. Given that the replenishment rate is also not [Ca⁺⁺]_o sensitive this puts into question a widely held notion that the vesicles—constrained by the cytoskeleton and rendered free from such constraints by Ca⁺⁺ entry that renders them more mobile—are important in the replenishment of the readily-releasable pool. This raises a question—Is vesicular replenishment of the readily releasable pool associated with significant movement? To answer this question we evaluated how okadaic acid and staurosporine (compounds known to affect vesicular mobility) influence the replenishment rate. We used patterned stimulation on the Schaffer collateral fiber pathway and recorded the excitatory post-synaptic currents (EPSCs) from rat CA1 neurons, in the absence and presence of these drugs. The parameters of a circuit model with two vesicular pools were estimated by minimizing the squared difference between the ESPC amplitudes and simulated model output. [Ca²⁺]_o did not influence the progressive decrease of the replenishment rate during long, high frequency stimulation. Okadaic acid did not significantly affect any parameters of the vesicular storage and release system, including the replenishment rate. Staurosporine reduced the replenishment coupling, but not the replenishment rate, and this is owing to the fact that it also reduces the ability of the readily releasable pool to contain quanta. Moreover, these compounds were ineffective in influencing how the replenishment rate decreases during long, high frequency stimulation. In conclusion at the excitatory synapses of rat hippocampus the replenishment of the readily releasable pool does not appear to be associated with a significant vesicular movement, and during long high frequency stimulation [Ca⁺⁺]_o does not influence the progressive decrease of vesicular replenishment.     

Temperate bioerosion: ichnodiversity and biodiversity from intertidal to bathyal depths (Azores)

In the temperate Azores carbonate factory, a substantial fraction of the calcareous skeletal components is recycled by a remarkable biodiversity of biota producing bioerosion traces (incipient trace fossils). To study this biodiversity, experimental carbonate substrates were exposed to colonisation by epilithic and endolithic organisms along a bathymetrical gradient from 0 to 500 m depth, during 1 and 2 years of exposure. The overall bioerosion ichnodiversity is very high and comprises 56 ichnotaxa and ichnoforms attributed to cyanobacteria, chlorophytes, fungi, other micro-chemotrophs, macroborers, grazers and epilithic attachment scars. In the intertidal, hydrodynamic force, partial emersion and strong temperature fluctuations lead to the lowest ichnospecies richness. This contrasts with the highest ichnodiversity found at 15 m under the most favourable environmental conditions. Towards aphotic depths, a gradual depletion in ichnodiversity is observed, most probably because of the restricted light availability and a slowdown in ichnocoenosis development. Analysis of similarity (ANOSIM), in combination with non-metrical multidimensional scaling (NMDS), was used to highlight variability in the relative abundance of traces among depths, substrate orientations and exposure times. Ichnodiversity and abundance of traces decrease significantly with depth and are higher on up-facing versus down-facing substrates, whereas differences between years were not as pronounced. This study demonstrates that statistical methods of biodiversity analysis are not per se restricted to biotaxa but may well be applied also to ichnotaxa. In the analysis of trace fossil assemblages, this approach supports the recognition of diversity patterns and their relation to environmental gradients.     

Bone morphogenetic protein (BMP)1-3 enhances bone repair

Small molecules that exhibit biological activity have contributed to the understanding of the molecular mechanisms of various biological phenomena. 5-Bromodeoxyuridine (BrdU) is a thymidine analogue that modulates various biological phenomena such as cellular differentiation and cellular senescence in cultured mammalian cells. Although BrdU is thought to function through changing chromatin structure and gene expression, its precise molecular mechanisms are not understood. To study the molecular mechanism for the action of BrdU, we have employed the yeast Saccharomycescerevisiae as a model system, and screened multi-copy suppressor genes that confer resistance to BrdU. Our genetic screen has revealed that expression of the N-terminal short fragment of TUP1, and also disruption of HDA1 or HOS1, histone deacetylases that interact with TUP1, conferred resistance to BrdU. These results suggest the implication of the chromatin proteins in the function of BrdU, and would provide novel clues to answer the old question of how BrdU modulates various biological phenomena.     

Macrolactonolides: A novel class of anti-inflammatory compounds

A new concept in design of safe glucocorticoid therapy was introduced by conjugating potent glucocorticoid steroids with macrolides (macrolactonolides). These compounds were synthesized from various steroid 17β-carboxylic acids and 9a-N-(3-aminoalkyl) derivatives of 9-deokso-9a-aza-9a-homoeritromicin A and 3-descladinosyl-9-deokso-9a-aza-9a-homoeritromicin A using stable alkyl chain. Combining property of macrolides to preferentially accumulate in immune cells, especially in phagocyte cells, with anti-inflammatory activity of classic steroids, we designed molecules which showed good anti-inflammatory activity in ovalbumin (OVA) induced asthma in rats. The synthesis, in vitro and in vivo anti-inflammatory activity of this novel class of compounds are described.     

Candidate gene SNP variation in floodplain populations of pedunculate oak (Quercus robur L.) near the species' southern range margin: Weak differentiation yet distinct associations with water availability

Populations residing near species' low‐latitude range margins (LLMs) often occur in warmer and drier environments than those in the core range. Thus, their genetic composition could be shaped by climatic drivers that differ from those occurring at higher latitudes, resulting in potentially adaptive variants of conservation value. Such variants could facilitate the adaptation of populations from other portions of the geographical range to similar future conditions anticipated under ongoing climate change. However, very few studies have assessed standing genetic variation at potentially adaptive loci in natural LLM populations. We investigated standing genetic variation at single nucleotide polymorphisms (SNPs) located within 117 candidate genes and its links to putative climatic selection pressures across 19 pedunculate oak (Quercus robur L.) populations distributed along a regional climatic gradient near the species' southern range margin in southeastern Europe. These populations are restricted to floodplain forests along large lowland rivers, whose hydric regime is undergoing significant shifts under modern rapid climate change. The populations showed very weak geographical structure, suggesting extensive genetic connectivity and gene flow or shared ancestry. We identified eight (6.2%) positive F_ST‐outlier loci, and genotype–environment association analyses revealed consistent associations between SNP allele frequencies and several climatic variables linked to water availability. A total of 61 associations involving 37 SNPs (28.5%) from 35 annotated genes provided important insights into putative functional mechanisms in our system. Our findings provide empirical support for the role of LLM populations as sources of potentially adaptive variation that could enhance species’ resilience to climate change‐related pressures.     

Involvement of damage-associated molecular patterns in tumor response to photodynamic therapy: surface expression of calreticulin and high-mobility group box-1 release

Damage-associated molecular patterns (DAMPs), danger signal molecules expressed after injury or infection, have become recognized as prerequisite for orchestrating effective anti-tumor host response. The expression of two prototypical DAMPs, calreticulin and high-mobility group box-1 (HMGB1) protein, was examined following Photofrin™-photodynamic therapy (PDT) of Lewis lung carcinoma (LLC) cells in vitro and LLC tumors growing in syngeneic mice. Cell surface expression of calreticulin was found to be highly increased at 1 h after PDT treatment both in vitro and in vivo. Increased exposure of calreticulin was also detected on the surface of macrophages from PDT-treated LLC tumors. At the same time interval, a rise in serum HMGB1 was detected in host mice. Intracellular staining of macrophages co-incubated for 16 h with PDT-treated LLC cells revealed elevated levels of HMGB1 in these cells. The knowledge of the involvement of these DAMPs uncovers important mechanistic insights into the development of host response induced by PDT.     

Reconstruction of a soft tissue defect of the back after myelomeningocele closure with modified V-Y plasty

Myelomeningocele is a congenital defect in vertebral arches with cystic dilatation of meninges and structural or functional abnormality of spinal cord or cauda equina. It is a form of spinal dysraphisam with overlying skin defect (spina bifida aperta). That condition is related to other clinical complications such as infection that can produce furthermore complications. To prevent rate of complications surgical treatment in first 24 h is strongly suggested. In this case report we describe a patient (infant) with congenital myelomeningocele who's defect was treated surgically by the neurosurgeon. In operative procedure plastic surgeon was involved to cover the skin defect remaining after neurosurgical closure of spinal canal. Bilateral advancement local skin flaps were used in soft tissue defect closure. Review of the literature that refers to advancement local skin flaps was carried out.     

Henoch-Schönlein purpura complicated by appendicitis, intussusception and ureteritis

Henoch-Sch?nlein purpura (HSP) is the most common childhood systemic small-vessel vasculitis with skin, joint, gastrointestinal (GI) and renal involvement. Uncommon GI complications are intussusception, bowel perforation and rarely reported appendicitis. HSP-associated stenosing ureteritis represents a rare and potentially serious complication. We present a 5-year-old boy with severe and prolonged course of HSP and three very rare complications that occurred sequentially: appendicitis, intussusception and ureteritis. Only three days after admission, he developed clinical signs of acute appendicitis indicating surgical intervention. Histological analysis of excised appendix showed inflammation but without signs typical for vasculitis. Two weeks later, with the reccurence of HSP he again developed clinical picture of acute abdomen. Ultrasound and radiologic evaluation demonstrated ileo-ileal intussusception and the second laparotomy was undertaken. Histological analysis of the resected bowel tissue showed typical signs of leucocytoclastic vasculitis. In the fourth week of his illness, serial urinalysis showed nephritic urinary sediment indicative of renal involvement. Unexpectedly, control abdominal ultrasound demonstrated mild hydronephrosis of the left kidney, not seen on previous ultrasound evaluations. Undertaken excretory urography and computed tomography (CT) scan showed stenosis of upper/ midureter with mild dilation of upper part of the left ureter suggesting unilateral HSP-associated stenosing ureteritis. Eventually, the patient was discharged and closely followed-up for the next two years. He had no further reccurence of HSP, the urinalysis normalized after six months, while mild unilateral hydronephrosis remained unchanged. Our search of the literature did not show reports of HSP complicated by appendicitis, intussusception and ureteritis, and to our knowledge this is the first case with three different illness events that occured sequentially. We emphasize the necessity of repeated ultrasound evaluations in the course of HSR especially in cases with severe GI and renal invovement.