Spermatophoric reaction reappraised: Novel insights into the functioning of the loliginid spermatophore based on Doryteuthis plei (Mollusca: Cephalopoda)

During copulation, spermatophores produced by male coleoid cephalopods undergo the spermatophoric reaction, a complex process of evagination that culminates in the attachment of the spermatangium (everted spermatophore containing the sperm mass) on the female's body. To better understand this complicated phenomenon, the present study investigated the functional morphology of the spermatophore of the squid Doryteuthis plei applying in vitro analysis of the reaction, as well as light and electron microscopy investigation of spermatangia obtained either in vitro, or naturally attached on females. Hitherto unnoticed functional features of the loliginid spermatophore require a reappraisal of some important processes involved in the spermatophoric reaction. The most striking findings concern the attachment mechanism, which is not carried out solely by cement adhesive material, as previously believed, but rather by an autonomous, complex process performed by multiple structures during the spermatophoric reaction. During evagination, the ejaculatory apparatus provides anchorage on the targeted tissue, presumably due to the minute stellate particles present in the exposed spiral filament. Consequently, the ejaculatory apparatus maintains the attachment of the tip of the evaginating spermatophore until the cement body is extruded. Subsequently, the cement body passes through a complex structural rearrangement, which leads to the injection of both its viscid contents and pointed oral region onto the targeted tissue. The inner membrane at the oral region of the cement body contains numerous stellate particles attached at its inner side; eversion of this membrane exposes these sharp structures, which presumably adhere to the tissue and augment attachment. Several naturally attached spermatangia were found with their bases implanted at the deposition sites, and the possible mechanisms of perforation are discussed based on present evidence. The function of the complex squid spermatophore and its spermatophoric reaction is revisited in light of these findings. J. Morphol. 2012. (C) 2011 Wiley Periodicals, Inc.

O enigma da "reação espermatofórica": breve síntese do conhecimento sobre a estrutura e o funcionamento dos espermatóforos dos cefalópodes (Mollusca: Cephalopoda)

Cefalópodes coleóides (lulas, sépias e polvos) produzem espermatóforos muito complexos que são transferidos à fêmea durante a cópula por meio do hectocótilo, um apêndice modificado nos machos. Durante a transferência à fêmea, ocorre a chamada "reação espermatofórica", complexo processo de evaginação do aparato ejaculatório do espermatóforo, que conduz à exteriorização da massa espermática e corpo cimentante. A presente revisão sintetiza o conhecimento acerca da morfologia e funcionamento desta estrutura exclusiva dos coleóides, identificando lacunas e definindo estratégias que possibilitem avanços na área. Poucos trabalhos abordam com detalhes a morfologia e anatomia funcional dos espermatóforos dos cefalópodes, grande parte do conhecimento acerca da estrutura do espermatóforo tendo sido gerada por trabalhos clássicos do século XIX e início do século XX. Investigações acerca do funcionamento dos espermatóforos são consideravelmente mais raras, estando o conhecimento básico sobre a reação espermatofórica restrito a apenas 19 espécies de coleóides. A revisão da literatura especializada permite sugerir que existem dois tipos básicos de fixação de espermatóforos em Decapodiformes (lulas e sepióides): fixação superficial e implante profundo (ou intra-dérmico). Na fixação superficial, comum em diversas espécies (e.g., Loliginidae, Sepiidae, Ommastrephidae), a base dos espermatângios é aderida ao tecido-alvo aparentemente por meio do corpo cimentante, a partir de substâncias adesivas e, em alguns casos, estruturas de fixação. No implante profundo, comum em alguns grupos de lulas oceânicas e de águas profundas (e.g., Architeuthidae, Cranchiidae, Octopoteuthidae, Sepiolidae), os espermatóforos implantam-se inteiramente no corpo da fêmea, de forma autônoma. Permanece desconhecido o mecanismo responsável pelo implante profundo. Em Octopodiformes (polvos), o espermatóforo é inserido no gonoduto feminino, alcançando a glândula oviducal, onde estão localizadas as espermatecas, ou a cavidade do ovário. Como o funcionamento extracorpóreo dos espermatóforos depende exclusivamente da intrincada estrutura e organização de seus componentes (e.g., membranas e túnicas), somente investigações detalhadas dessas estruturas proverão as bases para a compreensão do funcionamento e da exata função do complexo espermatóforo dos coleóides. Recomenda-se o desenvolvimento de um protocolo simples e eficiente para coloração e preparação total de espermatóforos, de forma que seja possível expandir as descrições morfológicas do espermatóforo em estudos taxonômicos e anatômicos, permitindo, portanto, ampliação do conhecimento acerca desta enigmática estrutura.

Unraveling the structure of squids' spermatophores: a combined approach based on Doryteuthis plei (Blainville, 1823) (Cephalopoda: Loliginidae)

Marian, J.E.A.R. and Domaneschi, O. 2012. Unraveling the structure of squids spermatophores: a combined approach based on Doryteuthis plei (Blainville, 1823) (Cephalopoda: Loliginidae). Acta Zoologica (Stockholm) 93: 281307. Male coleoid cephalopods produce elaborate spermatophores, which function autonomously outside the male body during copulation, undergoing a complicated process of evagination. In order to contribute to the understanding of this unique structure, this study investigated the morphology of the spermatophore of Doryteuthis plei applying several microscopy techniques. A hitherto unreported, much more complex structural arrangement was revealed for the loliginid spermatophore, the most striking findings being: (1) the complex, layered structure of the middle membrane, which bears an additional, chemically distinct segment surrounding part of the cement body; (2) the presence of a space between the inner tunic and middle membrane filled with a fine reticulated material; (3) the presence of stellate particles not only embedded in the spiral filament, but also closely applied to the inner membrane at the level of the cement body; (4) the presence of a pre-oral chamber in the cap region; and (5) the complex organization of the cement body, formed by two distinct layers encompassing contents of different chemical and textural properties. Careful literature reassessment suggests several of these features are common to loliginids, and to some extent to other squids. Their possible functional implications are discussed in light of our knowledge of the spermatophoric reaction mechanics.

A model to explain spermatophore implantation in cephalopods (Mollusca: Cephalopoda) and a discussion on its evolutionary origins and significance

Male coleoid cephalopods produce spermatophores that can attach autonomously on the female's body during a complex process of evagination called the spermatophoric reaction, during which the ejaculatory apparatus and spiral filament of the spermatophore are everted and exposed to the external milieu. In some deepwater cephalopods, the reaction leads to the intradermal implantation of the spermatophore, a hitherto enigmatic phenomenon. The present study builds upon several lines of evidence to propose that spermatophore implantation is probably achieved through the combination of (1) an evaginating-tube mechanism performed by the everting ejaculatory apparatus and (2) the anchorage provided by the spiral filament's stellate particles. The proposed theoretical model assumes that, as it is exposed to the external milieu, each whorl of the spiral filament anchors to the surrounding tissue by means of its sharp stellate particles. As the ejaculatory apparatus tip continues evaginating, it grows in diameter and stretches lengthwise, enlarging the diameter of the whorl and propelling it, consequently tearing and pushing the anchored tissue outward and backward, and opening space for the next whorl to attach. After the ejaculatory apparatus has been everted and has perforated tissue, the cement body is extruded, possibly aiding in final attachment, and the sperm mass comes to lie inside the female tissue, encompassed by the everted ejaculatory apparatus tube. It is proposed that this unique, efficient spermatophore attachment mechanism possibly evolved in intimate relationship with the adoption of an active mode of life by coleoids. The possible roles of predation pressure and sperm competition in the evolution of this mechanism are also discussed. (c) 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105, 711726.

Revisiting a medical case of "stinging" in the human oral cavity caused by ingestion of raw squid (Cephalopoda: Teuthida): new data on the functioning of squid's spermatophores

Male squid produce intricate spermatophores that, when transferred to the female, undergo the spermatophoric reaction, a complex process of evagination that leads to the attachment of the spermatangium, that is, the everted spermatophore containing the sperm mass. While this process is still not completely understood, the medical literature includes several reports of "oral stinging" (i.e., punctured wounds in the human oral cavity) following consumption of raw male squid, which contains undischarged spermatophores able to inflict such wounds. Here, we revisit a recent medical report of oral stinging by Shiraki et al. (Pathol Int 61:749-751, 2011), providing an in-depth reanalysis of their histological biopsies and revealing vital information on the functioning of squid spermatophores. The morphology of the spermatangia attached within the oral cavity is similar to the condition found in spermatangia naturally attached to female squids. The spermatangia were able to superficially puncture the superficial layers of the oral stratified squamous epithelium, and numerous, minute stellate particles from the squid spermatophore were found adhered to the oral epithelium. These findings corroborate previous hypotheses on the functioning of squid spermatophores, namely that spermatophore attachment generally involves tissue scarification, and that stellate particles play a vital role in the attachment process. Moreover, spermatophore attachment is confirmed to be autonomous (i.e., performed by the spermatophore itself) in another squid species (possibly a loliginid), and the results strongly indicate that the attachment mechanism is not dependent upon a specialized epithelium, nor a mate's specific chemical stimulus. From the pathological point of view, the best prophylactic measure at present is the removal of the internal organs of the raw squid prior to its consumption.

Influence Of Substrate Steps On The Catalytic Properties Of Pt Layers: The Ethanol Electrooxidation Reaction.

The ethanol oxidation reaction (EOR) is investigated on Pt/Au(hkl) electrodes. The Au(hkl) single crystals used belong to the [n(111)x(110)] family of planes. Pt is deposited following the galvanic exchange of a previously deposited Cu monolayer using a Pt(2+) solution. Deposition is not epitaxial and the defects on the underlying Au(hkl) substrates are partially transferred to the Pt films. Moreover, an additional (100)-step-like defect is formed, probably as a result of the strain resulting from the Pt and Au lattice mismatch. Regarding the EOR, both vicinal Pt/Au(hkl) surfaces exhibit a behavior that differs from that expected for stepped Pt; for instance, the smaller the step density on the underlying Au substrate, the greater the ability to break the CC bond in the ethanol molecule, as determined by in situ Fourier transform infrared spectroscopy measurements. Also, we found that the acetic acid production is favored as the terrace width decreases, thus reflecting the inefficiency of the surface array to cleave the ethanol molecule.

Compact Ag@fe3o4 Core-shell Nanoparticles By Means Of Single-step Thermal Decomposition Reaction.

A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine.

Polyphenol-enriched Cocoa Protects The Diabetic Retina From Glial Reaction Through The Sirtuin Pathway.

Cocoa is rich in flavonoids, which are potent antioxidants with established benefits for cardiovascular health but unproven effects on neurodegeneration. Sirtuins (SIRTs), which make up a family of deacetylases, are thought to be sensitive to oxidation. In this study, the possible protective effects of cocoa in the diabetic retina were assessed. Rat Müller cells (rMCs) exposed to normal or high glucose (HG) or H2O2 were submitted to cocoa treatment in the presence or absence of SIRT-1 inhibitor and small interfering RNA The experimental animal study was conducted in streptozotocin-induced diabetic rats randomized to receive low-, intermediate-, or high-polyphenol cocoa treatments via daily gavage for 16 weeks (i.e., 0.12, 2.9 or 22.9 mg/kg/day of polyphenols). The rMCs exposed to HG or H2O2 exhibited increased glial fibrillary acidic protein (GFAP) and acetyl-RelA/p65 and decreased SIRT1 activity/expression. These effects were cancelled out by cocoa, which decreased reactive oxygen species production and PARP-1 activity, augmented the intracellular pool of NAD(+), and improved SIRT1 activity. The rat diabetic retinas displayed the early markers of retinopathy accompanied by markedly impaired electroretinogram. The presence of diabetes activated PARP-1 and lowered NAD(+) levels, resulting in SIRT1 impairment. This augmented acetyl RelA/p65 had the effect of up-regulated GFAP. Oral administration of polyphenol cocoa restored the above alterations in a dose-dependent manner. This study reveals that cocoa enriched with polyphenol improves the retinal SIRT-1 pathway, thereby protecting the retina from diabetic milieu insult.

FiltekTM Silorane and FiltekTM Supreme XT resins: tissue reaction after subcutaneous implantation in isogenic mice

The aim of this study was to evaluate the tissue compatibility of a silorane-based resin system (FiltekTM Silorane) and a methacrylate-based nanoparticle resin (FiltekTM Supreme XT) after implantation in the subcutaneous connective tissue of isogenic mice. One hundred and thirty five male isogenic BALB/c mice were randomly assigned to 12 experimental and 3 control groups, according to the implanted material and the experimental period of 7, 21 and 63 days. At the end of each period, the animals were killed and the tubes with the surrounding tissues were removed and processed for microscopic analysis. Samples were subjected to a descriptive and a semi-quantitative analyses using a 4-point scoring system (0-3) to evaluate the collagen fiber formation and inflammatory infiltrate. Data were statistically analyzed using the Kruskal Wallis test (?=0.05). The results showed that there was no significant difference between the experimental and control groups considering the three evaluation periods (p>0.05). The silorane-based and the methacrylate-based nanoparticle resins presented similar tissue response to that of the empty tube (control group) after subcutaneous implantation in isogenic mice.

Effect of phosphate-bonded investments on titanium reaction layer and crown fit

This study analyzed the reaction layer and measured the marginal crown fit of cast titanium applied to different phosphate-bonded investments, prepared under the following conditions (liquid concentration/casting temperature): Rema Exakt (RE) - 100%/237°C, 75%/287°C, Castorit Super C (CS)-100%/70°C, 75%/141°C and Rematitan Plus (RP)- 100%/430°C (special to titanium cast, as the control group). The reaction layer was studied using the Vickers hardness test, and analyzed by two way ANOVA and Tukey's HSD tests (α = 0.05). Digital photographs were taken of the crowns seated on the die, the misfit was measured using an image analysis system and One-way ANOVA, and Tukey's test was applied (α = 0.05). The hardness decreased from the surface (601.17 VHN) to 150 μm (204.03 VHN). The group CS 75%/141°C presented higher hardness than the other groups, revealing higher surface contamination, but there were no differences among the groups at measurements deeper than 150 μm. The castings made with CS - 100%/70°C presented the lowest levels of marginal misfit, followed by RE -100%/237°C. The conventional investments CS (100%) and RE (100%) showed better marginal fit than RP, but the CS (75%) had higher surface contamination.

Could leprosy reaction episodes be exacerbated by oral infections?

INTRODUCTION: This study evaluated whether leprosy reactions could be associated with oral infection. METHODS: Leprosy patients (n = 38) with (Group I) and without (Group II) oral infections were selected. Reactions were identified from the clinical and histopathological features associated with serum C-reactive protein (CRP) and10kDa interferon-gamma-induced protein (IP-10) levels, determined before and after elimination of the foci of infection. RESULTS: Group I presented more reactions than group II did, and improvement of the reactions after dental treatment. Serum CRP and IP-10 did not differ before and after the dental treatment, but differed between the groups. CONCLUSIONS: Oral infection could be an exacerbating factor in leprosy reactions.

Reaction time assessment in children with ADHD

Attention deficit, impulsivity and hyperactivity are the cardinal features of attention deficit hyperactivity disorder (ADHD) but executive function (EF) disorders, as problems with inhibitory control, working memory and reaction time, besides others EFs, may underlie many of the disturbs associated with the disorder. OBJECTIVE: To examine the reaction time in a computerized test in children with ADHD and normal controls. METHOD: Twenty-three boys (aged 9 to 12) with ADHD diagnosis according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, 2000 (DSM-IV) criteria clinical, without comorbidities, Intelligence Quotient (IQ) >89, never treated with stimulant and fifteen normal controls, age matched were investigated during performance on a voluntary attention psychophysical test. RESULTS: Children with ADHD showed reaction time higher than normal controls. CONCLUSION: A slower reaction time occurred in our patients with ADHD. This findings may be related to problems with the attentional system, that could not maintain an adequate capacity of perceptual input processes and/or in motor output processes, to respond consistently during continuous or repetitive activity.

Influence of separate and mixed experimental designs on reaction times to two simple visual stimuli

Testing contexts have been shown to critically influence experimental results in psychophysical studies. One of these contexts that show important modulation of the behavioral effects of different stimulatory conditions is the separate (blocked) or mixed presentation of these stimulatory conditions. The study presents evidence that the apparent discriminabilities of two target stimuli can change according to which of these two testing contexts is used. A cross inside a ring and a vertical line inside a ring were presented as go stimuli in a go/no-go reaction time task. In one experiment, each of these stimuli was presented to a different group of volunteers and in another experiment they were presented to the same group of volunteers, randomly mixed in the blocks of trials. Similar reaction times were obtained for the two stimuli in the first experiment, and different reaction times (faster for the cross) in the second experiment. The latter result indicates that the two stimuli have different discriminabilities from the no-go stimulus; the cross having greater discriminability. This difference is however masked, presumably by the adoption of specific compensatory attentional sets, in a separate testing context.

Reaction-diffusion stochastic lattice model for a predator-prey system

We have the purpose of analyzing the effect of explicit diffusion processes in a predator-prey stochastic lattice model. More precisely we wish to investigate the possible effects due to diffusion upon the thresholds of coexistence of species, i. e., the possible changes in the transition between the active state and the absorbing state devoid of predators. To accomplish this task we have performed time dependent simulations and dynamic mean-field approximations. Our results indicate that the diffusive process can enhance the species coexistence.

Thermal decomposition of mercerized linter cellulose and its acetates obtained from a homogeneous reaction

Cellulose acetates with different degrees of substitution (DS, from 0.6 to 1.9) were prepared from previously mercerized linter cellulose, in a homogeneous medium, using N,N-dimethylacetamide/lithium chloride as a solvent system. The influence of different degrees of substitution on the properties of cellulose acetates was investigated using thermogravimetric analyses (TGA). Quantitative methods were applied to the thermogravimetric curves in order to determine the apparent activation energy (Ea) related to the thermal decomposition of untreated and mercerized celluloses and cellulose acetates. Ea values were calculated using Broido's method and considering dynamic conditions. Ea values of 158 and 187 kJ mol-1 were obtained for untreated and mercerized cellulose, respectively. A previous study showed that C6OH is the most reactive site for acetylation, probably due to the steric hindrance of C2 and C3. The C6OH takes part in the first step of cellulose decomposition, leading to the formation of levoglucosan and, when it is changed to C6OCOCH3, the results indicate that the mechanism of thermal decomposition changes to one with a lower Ea. A linear correlation between Ea and the DS of the acetates prepared in the present work was identified.