Octocoral Tissue Provides Protection from Declining Oceanic pH

Increase in anthropogenic pCO₂ alters seawater chemistry and could lead to reduced calcification or skeleton dissolution of calcifiers and thereby weaken coral-reef structure. Studies have suggested that the complex and diverse responses in stony coral growth and calcification, as a result of elevated pCO₂, can be explained by the extent to which their soft tissues cover the underlying skeleton. This study compared the effects of decreased pH on the microstructural features of both in hospite (within the colony) and isolated sclerites (in the absence of tissue protection) of the zooxanthellate reef-dwelling octocoral Ovabunda macrospiculata. Colonies and isolated sclerites were maintained under normal (8.2) and reduced (7.6 and 7.3) pH conditions for up to 42 days. Both in hospite and isolated sclerites were then examined under SEM and ESEM microscopy in order to detect any microstructural changes. No differences were found in the microstructure of the in hospite sclerites between the control and the pH treatments. In stark contrast, the isolated sclerites revealed dissolution damage related to the acidity of the water. These findings suggest a protective role of the octocoral tissue against adverse pH conditions, thus maintaining them unharmed at high pCO₂. In light of the competition for space with the less resilient reef calcifiers, octocorals may thus have a significant advantage under greater than normal acidic conditions.     

New investigation technique for thoracic sclerites of mosquitoes (Diptera, Culicidae) for the correct identification of genera and species

A new technique for studying the external morphology of thoracic sclerites of mosquitoes (Diptera: Culicidae) was developed. According to this method, the shape of sclerites and the position of setae and scales can be examined using SEM or light microscopy even in cases when setae or scales have been lost. The method can be recommended for the damaged material which is often obtained during sampling. The bases of setae usually exceed 100 μm in diameter and thus differ significantly from the bases of scales which are about 30 μm in diameter. Analysis of the structure of sclerites and the arrangement of setae and scales on them in different specimens of one species may reveal intraspecific variation of this character complex. Comparison of species from different genera of the family Culicidae, as well as comparison of closely related species, will probably help to estimate the diagnostic value of thoracic sclerites as morphological characters.     

Patterns of distribution of calcite crystals in soft corals sclerites

The gross morphology of soft coral surface sclerites has been studied for taxonomic purposes for over a century. In contrast, sclerites located deep in the core of colonies have not received attention. Some soft coral groups develop massive colonies, in these organisms tissue depth can limit light penetration and circulation of internal fluids affecting the physiology of coral tissues and their symbiotic algae; such conditions have the potential to create contrasting calcifying conditions. To test this idea, we analyzed the crystal structure of sclerites extracted from different colony regions in selected specimens of zooxanthellate and azooxanthellate soft corals with different colony morphologies, these were: Sarcophyton mililatensis, Sinularia capillosa, Sinularia flexibilis, Dendronephthya sp. and Ceeceenus levis. We found that the crystals that constitute polyp sclerites differ from those forming stalk sclerites. We also observed different crystals in sclerites located at various depths in the stalk including signs of sclerite breakdown in the stalk core region. These results indicate different modes of calcification within each colonial organism analyzed and illustrate the complexity of organisms usually regarded as repetitive morphological and functional units. Our study indicates that soft corals are ideal material to study natural gradients of calcification conditions. J. Morphol. 2011. © 2011 Wiley‐Liss, Inc.     

Comparative biometry and isotopy of three dominant pennatulacean corals in the Northwest Atlantic

Spatial and temporal shifts in biometric features were examined in three common deep‐water pennatulacean corals (sea pens) from the Northwest Atlantic: Anthoptilum grandiflorum, Halipteris finmarchica and Pennatula aculeata. These three species show different morphological characters and adaptations to their environment. Analyses of colony length, ratio of peduncle to colony length, weight/length ratio, polyp size and density as well as sclerite shape, location and abundance indicate that their phenotype is modulated by environmental factors (e.g. food availability, currents and sediment type) and antipredator strategies. Moreover, the three species had different carbon and nitrogen stable isotope signatures that could be explain primarily by their different polyp diameters and colony shapes, suggesting that they rely on slightly different food sources (varying proportions of phytodetritus and zooplankton). Finally, sclerites were found only in H. finmarchica and P. aculeata and are not known to occur in A. grandiflorum, except for minute oval bodies inside the peduncle. The Mg/Ca ratio of sclerites differed between the two species and, for P. aculeata, among types of sclerites, evoking different biomineralization pathways related to their functional roles (structural support or defence). Overall, this study provides new information on the ecology of poorly known species, which are ubiquitous and suspected to play an important ecological role in deep‐water ecosystems.     

The 46,000-dalton tyrosine protein kinase substrate is widespread, whereas the 36,000-dalton substrate is only expressed at high levels in certain rodent tissues

Proteins of molecular mass 46,000 (p46) and 34,000-39,000 (p36) daltons are phosphorylated at tyrosine in Rous sarcoma virus-transformed chicken and mouse fibroblasts. p46 has recently been identified as an isozyme of enolase but the function of p36 is unknown. The expression of these proteins in various mouse and rat tissues has been examined. In most tissues, except muscle, p46 is found at relatively constant levels. In muscle, a more basic, related protein is present. In contrast, the abundance of p36 varies more widely from tissue to tissue, suggesting that it has a function in some but not all differentiated cells. By SDS gel electrophoresis and immunoblotting, high levels of p36 (60-120% of its relative abundance in fibroblasts) were found in small intestine, lung, and thymus, and intermediate levels (20-50%) were found in spleen, lymph nodes, and testes. No p36 was detectable in brain and muscle. Where studied, p36 mRNA expression paralleled protein levels. The cell types within each tissue expressing p36 were identified by immunofluorescence and immunoperoxidase staining. These cell types include all endothelial cells and fibroblastic cells examined, as well as various epithelial cells, cardiac muscle cells, macrophages, and testicular interstitial cells. We were unable to detect p36 in skeletal or smooth muscle cells, erythrocytes, nerve cells, or lymphocytes in any of the examined tissues. p36 appears to be concentrated in the terminal web region of intestinal columnar epithelial cells.     

Broken Copulatory Organs are Low-Cost Adaptations to Sperm Competition in Redback Spiders

In some spiders, a discrete portion of the male's copulatory organ (the apical sclerite) breaks off during copulation and remains in the female's reproductive tract. Apical sclerites may prevent insemination by rivals (sperm competition), stimulate females to favourably bias paternity (cryptic choice) or breakage may reflect sexual conflict over copulation duration with little direct effect on paternity. It has been assumed that any benefits of organ breakage are balanced by a large cost (male sterility) in species where males could otherwise mate multiply, but this has never been experimentally tested. We examined these ideas in the Australian redback spider (Latrodectus hasselti Thorell 1870, Araneae: Theridiidae), a species where males are functionally sterile after one normal mating. We experimentally removed sclerites and found males were able to mate, had similar copulation durations and transferred similar numbers of sperm as males with intact sclerites. Benefits of organ breakage were examined by forcing intact, rival males to inseminate the same or opposite reproductive tracts (female have paired, independent tracts in this taxon) and assessing paternity as a function of sclerite location. As predicted, apical sclerites were typically deposited at the entrance to the female's sperm storage organ, where they could physically block insemination by rivals. First male precedence was common when males inseminated the same tract and deposited sclerites at the entrance to the spermatheca, but not when sclerites were found elsewhere in the tract, or when rivals inseminated opposite tracts (where physically blocking rivals was impossible). Our data show that, in redbacks, copulatory organ breakage is not a side‐effect of sexual conflict, is unlikely to be a cue for cryptic female choice, but allows males to avoid sperm competition. Moreover, copulatory organ damage can have minimal reproductive cost for males, so assumptions of sterility after organ breakage are unjustified without supporting data.     

Developmental regulation of insulin-like growth factor II mRNA in different rat tissues

Insulin-like growth factor II (IGF-II) is present at high levels in fetal and early neonatal rat plasma, and decreases profoundly following birth. In the present study, the levels of IGF-II RNA in different rat tissues at different ages were determined by hybridization to a rat IGF-II cDNA probe. IGF-II RNA was present in 11 of 13 fetal or neonatal tissues examined: at higher levels in muscle, skin, lung, liver, intestine, and thymus; at lower levels in brain stem, heart, cerebral cortex, kidney, and hypothalamus; and undetectable in spleen and pancreas (although the latter RNA was partially degraded). In each tissue, Northern blot hybridization revealed the presence of six IGF-II RNAs: 6, 4, 3.8, 2.2, 1.7, and 1.2 kilobase pairs, consistent with results previously observed in the BRL-3A rat liver cell line and attributed to alternative RNA processing. Although differences in the relative abundance of these RNAs were observed in different tissues, the same size species occurred in all tissues with the 4-kilobase pair RNA the most abundant species. RNAs from the different tissues were examined at six developmental ages (days 16 and 21 of gestation; days 2, 11, 22, and 75 after birth) by hybridization to slot blots and Northern blots. In lung, thymus, kidney, and brain stem, IGF-II RNA was expressed at higher levels in the fetus than after birth, whereas in muscle, skin, liver, heart, and intestine, the high fetal levels of IGF-II RNA continued through day 11 or day 22 after birth. IGF-II RNA persisted into adulthood in cerebral cortex and hypothalamus. Although the significance of these tissue-specific differences in the developmental regulation of the expression of IGF-II RNA remains to be established, they exhibit intriguing temporal correlations with major maturational events in some tissues such as lung and muscle.     

Tissue-specific regulation of rat estrogen receptor mRNAs

The estrogen receptor (ER) is present in a wide variety of mammalian tissues and is required for physiological estrogen responses, including estrogen-induced tissue-specific changes in gene expression. We studied the estrogen regulation of the mRNAs encoding the ER in rat uterus, liver, and pituitary. Ovariectomized (21-28 day post surgery) female CD-1 rats were injected daily with 17 beta-estradiol (E2, 10 micrograms/100 g BW) for 0, 1, or 4 h, 1, 3, or 7 days and compared with intact controls. Steady-state levels of ER mRNA were quantified using a human ER cDNA probe. Only one hybridizing species of approximately 6.2 kilobase (kb) was detected in uterine and liver RNA, similar to that observed in MCF7 human breast cancer cells. However, the ER mRNA regulation by E2 differed in direction depending on the tissue examined. In uterus, ER mRNA increased 3- to 6-fold after ovariectomy, and returned to intact levels within 24 h of E2 replacement. In contrast, liver ER mRNA declined 1.5- to 3-fold after ovariectomy and returned to intact levels after 1-3 days of E2. In pituitary tissue two hybridizing forms of ER mRNA were observed, with one species migrating at 6.2 kb, equivalent to the form in other tissues, and a second smaller species at approximately 5.5 kb. The lower molecular weight species varied somewhat in abundance from animal to animal, averaging about 20% of the intensity of the 6.2 kb band. The ER mRNA forms were regulated positively with E2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Plant population growth and competition in a light gradient: a mathematical model of canopy partitioning

Can a difference in the heights at which plants place their leaves, a pattern we call canopy partitioning, make it possible for two competing plant species to coexist? To find out, we examine a model of clonal plants living in a nonseasonal environment that relates the dynamical behavior and competitive abilities of plant populations to the structural and functional features of the plants that form them. This examination emphasizes whole plant performance in the vertical light gradient caused by self-shading. This first of three related papers formulates a prototype single species Canopy Structure Model from biological first principles and shows how all plant properties work together to determine population persistence and equilibrium abundance. Population persistence is favored, and equilibrium abundance is increased, by high irradiance, high maximum photosynthesis rate, rapid saturation of the photosynthetic response to increased irradiance, low tissue respiration rate, small amounts of stem and root tissue necessary to support the needs of leaves, and low density of leaf, stem, and root tissues. In particular, equilibrium abundance decreases as mean leaf height increases because of the increased cost of manufacturing and maintaining stem tissue. All conclusions arise from this formulation by straightforward analysis. The argument concludes by stating this formulation's straightforward extension, called a Canopy Partitioning Model, to two competing species.     

我国西南地区早寒武世小壳化石Sinosachites

采自四川峨嵋和云南会泽的磷酸盐化的Sinosachites骨片显示出中央沟和侧沟结构,并区别出三种不同类型的骨片(palmate,cultrate and siculate)。这一发现证实,产于澳大利亚的Thambetolepis(Jell,1981)是Sinosachites的晚出同义名。基于上述结构,该产地一些原定为Sachites和Halkieria的标本亦应归入Sinosachites。在Sinosachites属中确认出两个种,即产于华南的Sinosachites flabelliformis He和产于澳大利亚的Sinosachites delicatus(Jell)。在前一种中,左右型对称骨片的存在证实该动物两侧对称。骨片的基部通常保存为磷质内核,表明它比骨片壁更容易磷酸盐化,在组织学上它与骨片壁不同。骨片的基部可能原为有机质或部分矿化。在Sinosachites中,无帽状和束状骨片可能表明在coeloscleritophorans中halkieriids是一个介于wiwaxids和siphogonuchitids之间的类群。     

Morphology of the elytral base sclerites

The elytral base sclerites (= sclerites located at the articular region between the forewing and thorax in Coleoptera) of selected taxa were examined and homologized. Although the elytral base sclerites are highly modified compared to the wing base sclerites of the other neopterans, they can be homologized by using the conservative wing flapping and folding lines as landmarks. A reduction of the first axillary sclerite was identified as a general trend of the elytral base sclerites, although the sclerite usually has a very important function to mediate flight power from the notum to the wing. This result indicates that the functional constraint against the basal sclerites is relaxed because of the lack of an ability to produce flight power by elytra. In contrast, the elytral folding system formed by the basal sclerites is well retained, which probably occurs because proper wing folding is a key for the shelter function of the elytra. The elytral base sclerites apparently contain more homoplasies than the serially homologous hindwing base sclerites of Coleoptera, which suggests that the structure is less useful for higher-level systematics. However, the faster evolutionary rate of the elytral base sclerites suggests there is potential for studying the lower-level phylogeny of Coleoptera.     

Comparative Root Anatomy of Five Actinidia Species in Relation to Rootstock Effects on Kiwifruit Flowering

This study examined the root anatomy of five Actinidia specieswhich, when used as rootstocks, differ in their effects on flowerproduction of the 'Hayward' kiwifruit scion. The rootstock speciesexamined were A. hemsleyana, A. eriantha, A. rufa, A. deliciosaand A. chinensis. Roots of all the five species had similartissues and similar cell types in each tissue. The cortex andendodermis were retained and developed further during secondaryroot thickening. Each meriphyte of endodermal cells, derivedduring secondary growth, was enclosed in a suberin lamella.Crystalline idioblasts were present in the cortex and phloem.These idioblasts contained raphide crystals, often surroundedby mucilage. Roots of the five species differed significantlyin the total cross-sectional area of vessels in the xylem, inthe total cross-sectional areas of fibres and crystalline idioblastsin the phloem, and in the abundance of starch grains in parenchymaof all tissues. Roots of flower-promoting rootstock speciestended to have more and larger xylem vessels, more crystallineidioblasts, and more starch grains. These anatomical featuresmay be used as criteria for future selection of flower-promotingrootstocks in kiwifruit. The possible physiological link betweenroot anatomy and rootstock effect is discussed.Copyright 1994,1999 Academic Press Kiwifruit, Actinidia, root, anatomy, rootstock, flowering     

The dual role of sclerites in a gorgonian coral: Conflicting functions of support and defence

Sclerites in the gorgonian coral Briareum asbestinum perform the dual role of skeletal support against wave action and structural defence against predators. Local populations of B. asbestinum vary along gradients of decreasing water movement and decreasing predator abundance with increasing depth, such that sclerite length increases and sclerite density decreases with depth. Based on this pattern, I explored a possible trade-off between the sclerite composition that is most resistant to tearing versus most deterrent to predatory gastropods. Feeding assays revealed that artificial foods containing longer sclerites and those containing higher volume fractions of sclerites are less palatable to the gastropod Cyphoma gibbosum. However, real colonies appear constrained, in that they do not contain both long sclerites and high volume fractions at the same time. Given a choice among real colonies, snails prefer shallow-water colonies with shorter sclerites e ven though the sclerite volume fractions are high. Although least deterrent to snails, shallow-water colonies are 56% more resistant to tearing than their deep-water counterparts. Hence, variation in sclerite composition among local populations of B. asbestinum may be maintained by opposing selection for support versus defense.     

Gene expression in rat brain

191 randomly selected cDNA clones prepared from rat brain cytoplasmic poly (A)+ RNA were screened by Northern blot hybridization to rat brain, liver and kidney RNA to determine the tissue distribution, abundance and size of the corresponding brain mRNA. 18% hybridized to mRNAs each present equally in the three tissues, 26% to mRNAs differentially expressed in the tissues, and 30% to mRNAs present only in the brain. An additional 26% of the clones failed to detect mRNA in the three tissues at an abundance level of about 0.01%, but did contain rat cDNA as demonstrated by Southern blotting; this class probably represents rare mRNAs expressed in only some brain cells. Therefore, most mRNA expressed in brain is either specific to brain or otherwise displays regulation. Rarer mRNA species tend to be larger than the more abundant species, and tend to be brain specific; the rarest, specific mRNAs average 5000 nucleotides in length. Ten percent of the clones hybridize to multiple mRNAs, some of which are expressed from small multigenic families. From these data we estimate that there are probably at most 30,000 distinct mRNA species expressed in the rat brain, the majority of which are uniquely expressed in the brain.     

Peroxidase activity and inducibility in the sea fan coral exposed to a fungal pathogen

The enzymatic defense mechanisms of Gorgonia ventalina to the fungal pathogen Aspergillus sydowii may play important roles in colony resistance to infection. In this study, we examined the role of the superfamily of peroxidase enzymes in the coral response to a naturally occurring pathogen. We examined the inducibility of peroxidases by experimentally exposing corals to A. sydowii and found that peroxidase activity was induced after an 8 day incubation period. In contrast, naturally infected corals collected from the reef had lower peroxidase activity when compared to healthy corals. Infected sea fans from the field also had less measurable protein in their tissues and increased purple sclerites near infection sites and it is likely that these infections are months old. Using native-PAGE activity gels, we detected 5 peroxidase isozymes in healthy corals, indicating that multiple isoforms of peroxidase with a plurality of possible functions are present in this coral. The role of the peroxidase enzymes in disease resistance was examined by testing anti-fungal activity of commercially available and partially purified sea fan peroxidases. In both cases there was significant, dose-dependent anti-fungal activity. While peroxidases are ubiquitous enzymes involved in many cellular pathways, we also hypothesize that G. ventalina utilizes these enzymes as an integral component in disease resistance pathways. As such, they may also contribute to the initiation of physiochemical defenses such as melanization and lipid soluble anti-fungal metabolites.     

A new species of Monocotyle taschenberg, 1878 (Monogenea: Monocotylidae) from Dasyatis guttata (Dasyatidae)

Monocotyle guttatae n. sp. is described from the gills of the ray Dasyatis guttata (Bloch and Schneider, 1801) (Dasyatidae) off the coast of Brazil The new species can be readily differentiated from the other species of the genus in having a male copulatory organ with 2 loops and an accessory piece, 5-7 sclerites on the marginal haptoral papillae, and the absence of accessory sclerites on the dorsal surface of the posterior body. The present record confirms the presence of the genus in the subtropical waters of South America.     

Acanthotrema felis n. sp. (Digenea: Heterophyidae) from the small intestine of stray cats in the Republic of Korea

Acanthotrema felis n. sp. (Digenea: Heterophyidae) is described from adult flukes recovered in the small intestine of stray cats caught in the southwestern part of the Republic of Korea. The worms were characterized by minute body size, the presence of a bipartite seminal vesicle, and a ventral sucker associated with a ventrogenital sac, which enclosed 3 sclerites (2 long and pointed, and I short and thumblike), and an unarmed gonotyl. They were assigned to Acanthotrema Travassos, 1928, which currently contains 4 species. The new species resembles A. acanthotrema, the type species, because both have 3 sclerites on the ventrogenital sac. However, all 3 sclerites in the new species are armed with minute spines on their base, whereas only 2 sclerites in A. acanthotrema have minute spines near their tips. Three species of Stictodora Looss, 1899, namely,Stictodora tridactyla Martin and Kuntz, 1955, S. cursitans Kinsella and Heard, 1974, and S. tanayensis Velasquez, 1973, are transferred to Acanthotrema, and the new species is distinguished from them particularly in terms of the number and shape of its sclerites. The generic diagnosis of Acanthotrema is emended.