Planarians change in body size depending upon whether they are in feeding or starving conditions. To investigate how planarians regulate this flexible system, the numbers of total cells and specific cell types were counted and compared among worms 2 mm to 9 mm in body length. The total cell number increased linearly with increasing body length, but the ratio of cell numbers between the head and the trunk portion was constant (1:3). Interestingly, counting the numbers of specific neurons in the eye and brain after immunostaining using cell type-specific antibodies revealed that the ratio between different neuron types was constant regardless of the brain and body size. These results suggest that planarians can maintain proportionality while changing their body size by maintaining a constant ratio of different cell types. To understand this system and reveal how planarians restore the original ratio during eye and brain regeneration, the numbers of specialized cells were Investigated during regeneration. The results further substantiate the existence of some form of “counting mechanism” that has the ability to regulate both the absolute and relative numbers of different cell types in complex organs such as the brain during cell turnover, starvation, and regeneration.

Despite easy access to bivalves, few studies have examined the development of these animals, at least in part because most bivalve eggs are very small. In addition, annotating cells of the early bivalve embryo is difficult because few landmarks are present. We conducted detailed cell annotations of the Japanese purple mussel, Septifer virgatus, during early embryogenesis because of its relatively large eggs (ca. 130 µm in diameter). Septifer virgatus underwent the unique cell division profile reported for four other bivalve species, suggesting that the cleavage pattern itself is important for bivalve morphogenesis. The shell field invagination was led by 2d (X) lineage cells, supporting the hypothesis that lineage cells differentiate into cells excreting the shell matrix. The large egg size enabled us to trace cell movements in the early gastrulation phase, during which the invagination of the archenteron was initiated by 4d (M) lineage cells. These observations will serve as a basis for future analyses of S. virgatus embryogenesis and will contribute to understanding the evolution of the molluscan body plan, which is achieved by modification of early embryogenesis.

Food availability has been suggested to be the main factor shaping the altitudinal limits of species distributions. We analyzed the badger (Meles meles) diet in the western Italian Alps and, particularly, at the altitudinal limit of its range, with the main aim of highlighting any reduction in earthworm availability with altitude which could act as a limiting factor for badgers. Earthworms were by far the main food resource of badgers, followed by fruit. The two-month importance of these two items in badger diet was inversely correlated. Earthworm consumption was negatively correlated with air temperature. The seasonal pattern of earthworm use by badgers seemed to be influenced by the reproduction and estivation times of some epigeic species, rather than by climatic conditions per se. The eating of fruit by badgers was at least in part independent from the availability of earthworms. The badgers' efficacy in preying upon earthworms also in adverse conditions and their reliance on a wide variety of food resources suggest that worm availability might play a minor role in shaping the altitudinal limit of the species on the Alps.

The presence of three gonadotropin-releasing hormone (GnRH) forms in the brain of the chub mackerel, Scomber japonicus, namely, salmon GnRH (sGnRH), chicken GnRH-II (cGnRH-II), and seabream GnRH (sbGnRH), was confirmed by combined high performance liquid chromatography (HPLC) and time-resolved fluoroimmunoassay (TR-FIA). Immunocytochemical localization of the three GnRH forms in the brain was Investigated by using specific antisera, to elucidate possible roles of each GnRH form in reproduction in this species, and double immunolabeling was used to localize GnRH-ir (immunoreactive) fibers Innervating the pituitary. sGnRH-ir neurons were localized in the ventral olfactory bulb and terminal nerve ganglion region. Further, sGnRH-ir fibers were found in different regions of the brain, with prominent fibers running in parallel in the preoptic area (POA) without entering the pituitary. cGnRH-II-ir cell bodies were observed only in the midbrain tegmentum region, with a wide distribution of fibers, which were dense in the midbrain tegmentum and spinal cord. SbGnRH-ir cell bodies were localized in the nucleus preopticus of the POA, with fibers in the olfactory bulb, POA, and hypothalamus. Among the three GnRH forms, only SbGnRH-ir fibers innervated the pituitary gland from the preoptic-hypothalamic region, targeting follicle stimulating hormone (FSH) and luteinizing hormone (LH)-producing cells in the proximal pars distalis, as demonstrated by double immunocytochemistry. The localization of the GnRH-ir system was similar in male and female fish. These results demonstrate that multiple GnRH forms exist in the brain of the chub mackerel and suggest that they serve different functions, with SbGnRH having a significant role in reproduction in stimulating FSH- and LH-producing cells, and sGnRH and cGnRH-II serving as neurotransmitters or neuromodulators.

We examined whether a gonadotropin-releasing hormone (GnRH)-like peptide exists in the central nervous system (CNS) of the kuruma prawn, Marsupenaeus japonicus, by reverse-phase high performance liquid chromatography (rpHPLC) combined with time-resolved fluoroimmunoassay (TR-FIA) analysis and by immunohistochemistry. The displacement curve obtained for serially diluted extracts of the kuruma prawn brain paralleled the chicken GnRH-II (cGnRH-II) standard curve obtained by cGnRH-II TR-FIA using the anti-cGnRH-II antibody, which cross-reacts not only with cGnRH-II but also with lamprey GnRH-II (lGnRH-II) and octopus GnRH (octGnRH). Extracts of kuruma prawn brains and eyestalks showed a similar retention time to synthetic lGnRH-II and octGnRH in rpHPLC combined with TR-FIA analysis. Using this antibody, we detected GnRH-like-immunoreactive (ir) cell bodies in the anterior-most part of the supraesophageal ganglion (brain), the protocerebrum. Furthermore, GnRH-like-ir fibers were observed in the protocerebrum and deutocerebrum. In the eyestalk, GnRH-like-ir cell bodies were detected in the medulla interna, and GnRH-like-ir fibers were distributed in the medulla interna, medulla externa, and lamina ganglionalis. In the thoracic ganglion, GnRH-like-ir fibers, but not GnRH-like-ir cell bodies, were detected. No GnRH-like-ir cell bodies or fibers were detected in the abdominal ganglion or ovary. Thus, we have shown the existence and distribution of a GnRH-like peptide in the CNS of the kuruma prawn.

Compound eyes are common in decapod crustaceans. Decapods have an abundant post-Palaeozoic fossil record, but hitherto morphological information about their eyes has been mainly restricted to Recent material. Here we report the discovery of compound eyes recovered from acetic acid residues of two fish-bearing nodules from the Cretaceous Santana Formation of Brazil; they include what are identified as decapod larval compound eyes. The fossil eyes are comparable to phyllosoma larval eyes because of the following characters: the hemispherical visual surface on a stalked eye; the relatively small-size of the visual surface of the eye; rounded facets are arranged in square arrays in the anterior region; the fact that the neighboring ommatidia are bounded by ridges and/ or grooves; and the more convex inner surface of the cornea lens. This report represents the first description of a three-dimensionally preserved fossil decapod eye. We conclude that the eyes probably represent palinuroid phyllosoma larval eyes and were an adaptation to a planktonic lifestyle.

We determined the first complete mitochondrial genome (mitogenome) sequence from a representative of the insect family Delphacidae, Laodelphax striatellus. The 16,513 bp long L. striatellus mitogenome encodes 13 putative proteins, two ribosomal RNAs, and 22 transfer RNAs, and contains a putative control region (or A T-rich region). The nucleotide composition is biased toward adenine and thymine (77.2% A T), and the amino acid composition is affected to a similar degree by the AT mutational bias. All 13 protein-coding genes (PCGs) start with a typical ATN initiation codon. Eight of 13 PCGs in L. striatellus have a complete termination codon (TAA), whereas the remaining five have incomplete termination codons. The anticodons of the L. striatellus tRNAs are identical to those in Drosophila yakuba, and all tRNAs except for tRNA^Ser-AGN can be folded in the form of a typical cloverleaf structure. The A T-rich region of L. striatellus was found between srRNA and tRNA^lle, and the entire region was 2040 bp long. The gene content of the L. striatellus mitogenome is identical to other completely sequenced insect mitogenomes, while the gene order is different from the common arrangement found in most insects: five tRNA genes and three PCGs in the L. striatellus mitogenome have changed positions relative to the ancestral arrangement of mitochondrial genes in D. yakuba. Besides describing the above contents, we also aligned the mitogenome sequence of L. striatellus with other hemipterans to analyse the phylogenetic relationships of Hemiptera. The results show that Heteroptera is the sister group to all other Hemiptera, and Cicadomorpha is the sister group to the clade Fulgoromorpha Sternorrhyncha.

An insulin-related peptide, bombyxin, in the silkmoth Bombyx mori is secreted by four pairs of cerebral neurosecretory cells that form a weakly coupled oscillator system to produce a pulsatile pattern of hormone secretion. The activity of individual bombyxin-producing (BP) cells oscillated with different periods (20–70 min). The population of BP cells exhibited complex phase dynamics, including spontaneous synchronization and desynchronization of different combinations of cells. Statistical cross-correlation analyses of oscillation patterns between BP cells revealed that one cell usually correlated closely with a few particular cells of similar periodicity. Close investigation of the phase differences between individual active phases of the related cell pairs revealed that an inphase synchronous state was usually maintained for many cycles, whereas an antiphase state was transient, lasting for a few cycles. In contrast, antiphase synchronous states often occurred between several cell pairs when the brain containing the cerebral neurosecretory cell system was disconnected from the ventral nerve cord containing the neuronal mechanism that induced periodic heartbeat reversals at intervals of 80–110 min and exerted a periodic suppressive or phase-resetting effect on individual BP cells. These results suggest that the internal coupling mechanism in the BP cell system is not sufficient to maintain an in-phase synchronous state in the heterogeneous cell population, and that the external phase resetting mechanism may assist in-phase synchronization of many neurosecretory cells to generate an overall pulsatile pattern of bombyxin secretion.

Egg chorion precursors (zona radiata proteins; Zrps) were purified from the blood plasma of female Atlantic cod (Gadus morhua) by salting-out and column chromatography. The salting-out procedure employed a relatively low (30%) concentration of saturated ammonium sulfate. This was a critical step that separated Zrps from approximately 89% of other plasma proteins. Subsequently, three subtypes of Zrp (Zrp-α, -β and -γ) were purified by four (Zrps-α, -γ) or five (Zrp-β) serial column chromatography steps. The Intact masses of purified Zrp-α, -β and -γ were 290 kDa, 134 kDa, and 73 kDa, while masses estimated by SDS-PAGE were 78 kDa, 54 kDa, and 47 kDa, respectively. Antibodies were prepared against Zrp-β and -γ and utilized to develop specific immunoassays. The plasma levels of Zrp-β and -γ In reproductive female cod were estimated to be 591.42±77.59 µg/ml and 768.71±120.39 µg/ml, respectively. Thus, practical procedures for the separation of Zrp subtypes were developed in cod, which resulted in the development of subtype-specific Zrp immunoassays in this species; a similar method could be adopted for the separation, detection, and quantification of Zrp subtypes in other teleosts.

In the present study, we redescribe and compare Cardiodactylus novaeguineae (Haan, 1842) and Cardiodactylus guttulus (Matsumura, 1913), completing previous descriptions and adding many information on morphology, including both male and female genitalia and forewing venation, distribution, habitat, behavior, calling, and courtship songs. A neotype series is selected for C. novaeguineae and deposited in RMNH, Leiden MNHN, Paris, AMNH, New York and SAMA, Adelaide. The male of C. guttulus is described, and the species C. boharti Otte, 2007, is synonymised under C. guttulus.