Phylogenetic study of the arginine-vasotocin/arginine-vasopressin-like immunoreactive system in invertebrates

1. A phylogenetic study of arg-vasotocin (AVT)/arg-vasopressin (AVP)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata; Neanthes japonica and Pheretima communissima of the Annelida; Pomacea canaliculata, Aplysia kurodai, Oncidium verrucosum, Bradybaena similaris, Achatina fulica, Limax marginatus and Meretrix lamarckii of the Mollusca; Gnorimosphaeroma rayi, Hemigrapsus sanguineus, Gryllus bimaculatus and Baratha brassicae of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 3. No immunoreactivity was detected in Bipalium sp. of the Platyhelminthes, or in Procambarus clarkii and Helice tridens of the Arthropoda. 4. From these results, it appears that AVT/AVP is a phylogenetically ancient peptide which is present in a wide variety of invertebrates. 5. The actions of AVT/AVP and its presence in invertebrates are discussed.     

Immunohistochemical study on oxytocin-like substance in the human placenta

Our previous studies have demonstrated that a large quantity of oxytocin (OT)-like substance exists in human placental tissue. In the present study, the localization of the OT-like substance in the human placenta was investigated by the PAP (peroxidase and antiperoxidase complex) immunohistochemical method. The results demonstrated that the site of syncytiotrophoblast was positively stained by specific antiserum to OT, whereas the tissue was not significantly stained by normal rabbit serum (NRS). These results suggest that the OT-like substance might be localized in syncytiotrophoblast of the placental tissue.     

Phylogenetic grouping, curvature and metabolic scaling in terrestrial invertebrates

For more than a century, the scaling of animal metabolic rates with individual body masses and environmental temperature has predominantly been described by power-law and exponential relationships respectively. Many theories have been proposed to explain these scaling relationships, but were challenged by empirically documented curvatures on double-logarithmic scales. In the present study, we present a novel data set comprising 3661 terrestrial (mainly soil) invertebrate respiration rates from 192 independent sources across a wide range in body masses, environmental temperatures and phylogenetic groups. Although our analyses documented power-law and exponential scaling with body masses and temperature, respectively, polynomial models identified curved deviations. Interestingly, complex scaling models accounting for phylogenetic groups were able to remove curvatures except for a negative curvature at the highest temperatures (>30 °C) indicating metabolic down regulation. This might indicate that the tremendous differences in invertebrate body architectures, ecology and physiology may cause severely different metabolic scaling processes.     

The endocannabinoid system in invertebrates

What is the role of the cannabinoid system in invertebrates and can it tell us something about the human system? We discuss in this review the possible presence of the cannabinoid system in invertebrates. Endocannabinoid processes, i.e., enzymatic hydrolysis, as well as cannabinoid receptors and endocannabinoids, have been identified in various species of invertebrates. These signal molecules appear to have multiple roles in invertebrates; diminishing sensory input, control of reproduction, feeding behavior, neurotransmission and antiinflammatory actions. We propose that since this system worked so well, it was retained during evolution, and that invertebrates can serve as a model to study endogenous cannabinoid signaling.     

Hypothalamo-neurohypophysial system in hagfish: localization of neurophysin-, arg-vasopressin- and oxytocin-like immunoreactivity

Serial paraffin sections of hagfish brain (Eptatretus burgeri) were immunocytochemically examined for porcine neurophysin (NEU), arg-vasopressin (AVP) and oxytocin (OT). A big number of NEU-immunoreactive nerve cells were visible in the frontal part of the ventromedial hypothalamus in close vicinity of the third ventricle. These cells were bipolar in most cases and sometimes additionally stained for AVP but not for OT. NEU-reactive neurons extended axons to the median eminence and the posterior lobe of the pituitary which also contained AVP or OT-like immunoreactivity. Immunostaining outside the hypothalamus could not be observed. It is likely that there exists a mammalian-like oxytocinergic and a vasopressinergic hypothalamo-neurohypophysial system in hagfish, despite the large differences in levels of organization.     

Phylogenetic analysis of coccidian parasites from invertebrates: search for missing links

Apicomplexan parasites represent one of the most important groups of parasitic unicellular eukaryotes comprising such important human parasites such as Plasmodium spp. and Toxoplasma gondii. Apicomplexan radiation as well as their adaptation to the parasitic style of life took place before the era of vertebrates. Thus, invertebrates were the first hosts of apicomplexan parasites that switched to vertebrates later in evolution. Despite this fact, apicomplexan parasites of invertebrates, with the exception of gregarines, have so far been ignored in phylogenetic studies. To address this issue, we sequenced the nuclear SSU rRNA genes from the homoxenous apicomplexan parasites of insects Adelina grylli and Adelina dimidiata, and the heteroxenous Aggregata octopiana and Aggregata eberthii that are transmitted between cephalopods and crustaceans, and used them for phylogenetic reconstructions. The position of the adelinids as a sister group to Hepatozoon spp. within the suborder Adeleorina was stable regardless of the phylogenetic method used. In contrast, both members of the genus Aggregata possess highly divergent SSU rRNA genes with an unusual nucleotide composition. Because of this, they form the longest branches in the tree and their position is variable. However, the genus Aggregata branches together with adelinids and hepatozoons in most of the analyses, although their position within the scope of this cluster is unstable.     

A study of the hatching process in aquatic invertebrates

Summary The hatching process was observed in eggs of Notonecta melaena. A thick outer egg membrane ruptured at the cephalic end by pressure from within, exerted by the expansion of an inner egg membrane which forms a blister over the head. The osmotic nature of this expansion is demonstrated. The pronymph then drank water and its head pushed forward. At the same time, the blister membrane broke. The pronymph then emerged by a combination of a swelling of its body and a worm-like expansion and contraction in the abdominal region. The body swelled from a copious ingestion and absorption of water. The appendages did not participate in any way during hatching. At the termination of the emergence, a second inner membrane was ruptured. Shortly thereafter the pronymph underwent an ecdysis and swam away as a fully formed nymph.The eggs of Ranatra absona hatched in a somewhat similar manner, but the blister membrane was broken only after the head pushed against it. Also, the second inner membrane was ruptured long before the emergence of the nymph had been completed. In addition, there was no pronymphal stage and no ecdysis immediately after emergence.The eggs of Amnicola (?) hydrobioides are described. They were laid at an advanced stage of development. The young were very small (ca. 350 × 270 µ) and were surrounded by single egg membranes whose diameters were about % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaGOmaKaaGm% aaliaabaGaaGymaaqaaiaaikdaaaaaaa!385B!\[2{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}\] times that of the young. Hatching was through a mechanical tearing motion by the foot and proboscis, but the tearing reflex set in only after the egg membrane collapsed. Evidence is presented which suggests that the collapse was caused by the enzymatic softening of the membrane.

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Sumario Eclosión se observa en los huevos de Notonecta melaena. La membrana exterior del huevo se rompe en la extremidad cefálica por presión desde el interior. Esta presión se deriva de la expansión de una membrana interior, que forma sobre la cabeza una ampolla. Es demonstrado que ésta expansión es de tipo osmótico.. Entoncces la proninfa bebe agua y empuja hacia adelante. Al mismo tiempo la membrana la de ampolla se rompe. Entonces sale la proninfa por combinación la de hinchazón del cuerpo y la expansón y abreviatura del abdomen,, como de la un gusano. El cuerpo se hincha debido a la gran imbibición de agua. Las patas no participan en algunas de estas acciones. Al final de la eclosión la segunda membrana interior se rompe. Poco tiempo despues la proninfa vierte su esqueleto exterior y nada como una ninfa verdadera.Los huevos de Ranatra absona se rompen de una manera semejante, pero la membrana dela ampolla se rompe despures de que la cabeza la ha empujado. Además, la segunda membrana interior se rompe despues de que la ninfa ha salido completamente. Tampoco hay etapa proninfal y no hay muda de esqueleto exterior immediatemente despues de la salida.Los huevos de Amnicola (?) hydroboides han sido descritos. Ellos son puestos en un estado avanzado de desarrollo. Los jóvenes son muy pequeños (ca. 350 × 270 µ) y están circundados por membranas únicas que tienen diámetros cerca de% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaGOmaKaaGm% aaliaabaGaaGymaaqaaiaaikdaaaaaaa!385B!\[2{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}\] veces más que los de los jóvenes. Eclosión es por causa de una rotura mecánica de la membrana por accion del pie y probóscide, pero la acción refleja de rotura occure solamente despues de un hundimiento de la membrana del huevo. Se han presentado evidencias que indican que este hundimiente es ocasionado por un ablandamiento enzimático de la membrana.

     

Phylogenetic analysis of the light-harvesting system in Chromera velia

Chromera velia is a newly discovered photosynthetic eukaryotic alga that has functional chloroplasts closely related to the apicoplast of apicomplexan parasites. Recently, the chloroplast in C. velia was shown to be derived from the red algal lineage. Light-harvesting protein complexes (LHC), which are a group of proteins involved in photon capture and energy transfer in photosynthesis, are important for photosynthesis efficiency, photo-adaptation/accumulation and photo-protection. Although these proteins are encoded by genes located in the nucleus, LHC peptides migrate and function in the chloroplast, hence the LHC may have a different evolutionary history compared to chloroplast evolution. Here, we compare the phylogenetic relationship of the C. velia LHCs to LHCs from other photosynthetic organisms. Twenty-three LHC homologues retrieved from C. velia EST sequences were aligned according to their conserved regions. The C.?velia LHCs are positioned in four separate groups on trees constructed by neighbour-joining, maximum likelihood and Bayesian methods. A major group of seventeen LHCs from C. velia formed a separate cluster that was closest to dinoflagellate LHC, and to LHC and fucoxanthin chlorophyll-binding proteins from diatoms. One C. velia LHC sequence grouped with LI1818/LI818-like proteins, which were recently identified as environmental stress-induced protein complexes. Only three LHC homologues from C. velia grouped with the LHCs from red algae.     

Daily variations of immunoreactive melatonin in the visual system of crayfish

In crustaceans, melatonin has been detected in the central nervous system and some other organs. The aim of this study was to analyze the melatonin content in the visual system of Procambarus clarkii, by means of radioimmunoassay, at different day-night phases. We have also studied the action of exogenous melatonin on the main properties of the electroretinogram (ERG) circadian rhythm. Experiments were conducted with 25 specimens maintained under controlled conditions of 16°C and 12 h of light alternating with 12 h of darkness. Eyes where cut in dim red light and shock frozen with liquid nitrogen and pulverized in a mortar until a homogenous powder was obtained. Melatonin was extracted with acetone, followed by centrifugation, diluted with an equal volume of equa bidest to ensure freezing at ?80°C for at least 90 min and lyophilization at the same temperature. Lyophilizates, after having been dissolved in RIA buffer, were used for determinations of melatonin. Long-term recordings of electrical responses to light (ERG) were obtained for 10 or more consecutive days. At the 5th day, a single dose of melatonin was injected and its effects on amplitude and period of the ERG circadian rhythm were measured. Melatonin concentrations differed considerably depending on the circadian time and attained a maximum during dark phase. Among the crustaceans, Procambarus clarkii represents the first case in which melatonin peaks during the night following the typical pattern known in the majority of organisms. After melatonin injection, period and amplitude of the ERG circadian rhythm were increased. This effect suggests the involvement of melatonin in the oscillators underlying the generation and expression of circadian rhythms in crayfish.     

A study on the faeces of some chalk stream invertebrates

An account is given of the size, form, texture, colour, cohesion and composition of the faeces of 41 species of invertebrates found in chalk streams. The relationships between the character of the faeces and the taxonomic positions and habits of the producers are considered.The importance of faeces production relative to the bulk of stream bed sediments is discussed. Faeces of different origins accumulate in different areas of the stream bed and these differences may be associated in part with their form and structure and in part with the distribution of the species from which they originate. In the summer months tubificid worms alone may be responsible for reworking between 0.3% and 0.5% of the fine particulate material in sediments every day.     

Distribution of Eisenia tetradecapeptide immunoreactive neurons in the nervous system of earthworms

A detailed mapping of Eisenia-tetradecapeptide-immunoreactive neurons in the central and peripheral nervous system combined with quantitative morphological measurements was performed in Eisenia fetida and Lumbricus terrestris. In Eisenia, most labelled neurons were observed in the ganglia of the ventral cord (20.38% of the total cell number of the ganglion) and 15.67% immunoreactive cells occurred in the brain, while 6% of the neurons could be shown in the subesophageal ganglion. In the case of Lumbricus, most immunoreactive cells were found in the subesophageal ganglion (16.17%) and in the ventral ganglia (12.54%). The brain contained 122 ETP-immunoreactive cells (5.6%). The size of the immunoreactive cells varied between 35-75 microm. A small number of Eisenia-tetradecapeptide immunoreactive fibres were seen to leave the ventral ganglia via segmental nerves, and labelled processes could also be observed in the stomatogastric system and the body wall. Labelled axon branches originating from the segmental nerves formed an immunoreactive plexus both between the circular and longitudinal muscle layer and on the inner surface of the longitudinal muscle layer. This inner plexus was especially rich in the setal sac. Among the superficial epithelial cells the body wall contained a significant number of immunoreactive cells. Only a few Eisenia-tetradecapeptide immunoreactive neurons and fibres occurred in the stomatogastric ganglia. In the enteric plexus the number of immunoreactive neurons and fibres decreased along the cranio-caudal axis of the alimentary tract. Eisenia-tetradecapeptide immunoreactive cells were also present among the epithelial cells in the alimentary canal. Some of these cells resembled sensory neurons in the foregut, while others showed typical secretory cell morphology in the midgut and hindgut.     

动物生物标志物在土壤污染生态学研究中的应用

应用陆栖无脊椎动物的生物标志物对土壤生态系统中污染物的暴露和效应进行评价日益受到重视,并取得了显著的研究进展,文中介绍了溶酶体、胁迫蛋白和金属硫蛋白(MTs)3种主要生物标志物,体腔细胞内溶酶体膜稳定性用中性红保持时间(NRR)进行检测;胁迫蛋白类多采其中的Hsp70和Hsp60;金属硫蛋白不同同分异构体的定量分析可用于反映不同的金属污染胁迫,对3种生物标志物机理、特性、检测实例以及在污染土壤生态毒理诊断中的应用前景进行了评述。     

Recent advances in the study of long-distance dispersal of aquatic invertebrates via birds

Although Darwin pioneered the study of long‐distance dispersal (LDD) of aquatic invertebrates via waterbirds, it remains in its infancy as a modern discipline. A handful of recent studies have quantified internal or external transport in the field, confirming that a variety of long‐distance migrants carry invertebrates both internally and externally. These studies show that variation in the morphology of vectors influences the frequency and size of propagules transported, and suggest that more invertebrate groups disperse via birds than was previously thought. Dispersal limitation has mainly been investigated for zooplankton in small experimental systems from which waterbirds were effectively excluded, and the extent of such limitation for invertebrate populations in wetlands interconnected by waterbird movements remains unclear. We expect that the spatial and temporal scales at which dispersal limitation constrains geographical ranges, species richness and genetic structure of invertebrates depends partly on the density of migratory birds using the area. Birds may have a major role in the expansion of exotic species. We propose several avenues for future research. There is a particular need for more quantitative studies of LDD by birds that will enable modellers to assess its role in maintaining invertebrate biodiversity among increasingly fragmented wetlands and in the face of climate change, as well as in the spread of invasive species.