The effects of temperature on the occurrence of melanotic inclusions and related physiology in a sawfly, Gilpinia hercyniae

When penultimate larvae of Gilpinia hercyniae are exposed to 30°C, a high percentage of them develop melanotic inclusions from the midgut and/or Malpighian tubules early in the last instar; but in those exposed to lower temperatures (26 to 14°C), the frequency of inclusions is relatively low. Other abnormalities occur at 30°C, including high mortality, accumulations of excreta in the Malpighian tubules and midgut, and a failure to accumulate haemolymph proteins; these abnormalities are reflected in low amounts of dry matter and nitrogen in the last instar and high percentages of nitrogen in the faeces, by comparison with larvae exposed to 22 and 14°C and suggest an increased catabolism of nitrogen at the expense of protein. An increase, with temperature, in the level of uric acid stored in the body of the last instar is evidence of an enhanced nitrogen catabolism. The inclusions contain uric acid, suggesting that accumulations of excreta contribute to their formation and if so, an increased excretion of nitrogen at 30°C may be an underlying cause of their increase in frequency.     

Adaptive Mechanisms in the compound eye of Squilla mantis (Crustacea,Stomatopoda)

Summary Light and dark adaptations were studied in the eye of Squilla mantis. Light adaptation is characterized by (1) a proximal shift of the distal pigment sheath (DPS) surrounding the proximal portion of the crystalline cone above its zone of contact with the rhabdom; (2) flattening of the distal pigment sheath; (3) lengthening of the crystalline cone correlated with shortening of the rhabdom; (4) a migration of screening pigment granules in retinula cells in the protoplasmic bridges crossing the perirhabdomal space. In animals kept in constant darkness, longitudinal displacements of the distal pigment sheath were found to be subject to a circadian rhythm characterized by a maximal light adaptation state at about 5 p.m. and a minimal one at 5 a.m. Screening pigment granule translocation in retinula cells does not show such rhythmic activity.Abbreviations a, b maximal incidence angles in L.A., and D.A., respectively - Cc crystalline cone - Dps distal pigment sheath - I extreme incident light beam - Prs perirhabdomal space - Rh rhabdom - Rp reflecting pigment This research has been supported by grant 3.012-76 of the Swiss National Science Foundation     

The genetic relationship between the tomato mutants,flacca and lateral suppressor,with reference to abscisic acid accumulation

Two tomato mutants, Lycopersicon esculentum flacca and lateral suppressor, are assigned to map position 59 of chromosome 7. The tight linkage between these two gene loci was detected as a result of attempts to establish whether they would exhibit phenotypic interaction. The possibility that both mutants result in abnormalities of abscisic acid (ABA) accumulation is considered. ABA analysis supports the suggestion that plants homozygous for flacca have a substantially lower concentration but indicates that lateral suppressor homozygotes do not differ from normal in ABA content. An attempt is made to reconcile the results with those of Tucker (1976, New. Phytol. 77, 561–568) by suggesting that lateral suppressor plants may accumulate high levels of an ABA metabolite which is indistinguishable from ABA using the Commelina epidermal strip bioassay.Abbreviations ABA abscisic acid - flc flacca - ls lateral suppressor - La Lanceolate     

Crystalloid Inclusions in Species of Leucocytozoon,Parahaemoproteus, and Plasmodium*†

Cytoplasmic vacuoles seen in methanol-fixed, Giemsa's-stained ookinetes of Leucocytozoon simondi, Parahaemoproteus fringillae and Plasmodium gallinaceum, when studied with the electron microscope, were found to correspond with crystalloid inclusions of similar structure, particle size, and arrangement. Cytochemical examination of these “crystalloids” revealed their lipid-protein nature. Morphologically similar inclusions were found also in ookinetes of Leucocytozoon ziemanni and Parahaemoproteus velans. In L. simondi, crystalloid is formed rapidly after fertilization, from amorphous electron dense material seen in mature macrogametocytes. The arrangement and distribution of crystalloids in the zygote, ookinete, oocyst, and sporozoite are described. On the basis of differences in structure and particle size, it is proposed that the crystalloid inclusions in Haemosporina be divided into 2 types. Type I—lipid-protein in nature, characterized by electron dense irregularly spherical particles, 25–40 nm in diameter, with individual particles not invested by membrane. Type II—probably virus, characterized by electron dense, irregularly spherical, membrane-bounded particles, with a diameter usually greater than 40 nm.     

Effect of jasmonates and exogenous polysaccharides on production of alkannin pigments in suspension cultures of Alkanna tinctoria

Summary The conditions for the efficient production of alkannin pigments by a suspension culture of Alkanna tinctoria were established. Pectin, polygalacturonic acid sodium salt and galactan increased the pigment production but not as much as agar did. A marked increase in the pigment content in cells and medium of suspension cultures after treatment with methyl jasmonate was observed. It was shown, applying a two-layer culture method, that mineral and olive oils intensified the pigment secretion from cells to the medium but did not enhance significantly their synthesis. Thin layer chromatography and high performance liquid chromatography methods showed that two main esters of alkannin are responsible for the characteristic colour of A. tinctoria suspension cultures.Abbreviations BAP 6-benzylaminopurine - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indole 3-acetic acid - NAA 1-naphthaleneacetic acid - MeJA methyl jasmonate - TLC thin layer chromatography - HPLC high performance liquid chromatography     

Ultrastructural investigations of presumed photoreceptors as a means of discrimination and identification of closely related species of the genus Microphthalmus (Polychaeta,Hesionidae)

Summary Differences in the ultrastructure of presumed photoreceptors of three morphologically similar Microphthalmus populations on the opposite sides of the Atlantic (German North Sea coast and coasts of North Carolina and Massachusetts) suggest the existence of three different species. Only the European M. listensis possesses three pairs of prostomial eyes, of which one pair has rhabdomeric receptors and pigment cells. The two other pairs are unpigmented and can be found in all three species. The frontal one has ciliary receptors, the posterior one rhabdomeric sensory cells. An additional unpaired potential photoreceptor organ in the segment with the first pair of tentacular cirri is present in all individuals of this species complex. It has a relatively high number of cilia with numerous microvillar projections. — For each type of ocellus there are slight but distinct and constant differences among the species such as relative position of sensory cells, presence of dilations of the ciliary shafts, number of cilia, and shape of the sensory cells. Presence of both ciliary and rhabdomeric light-sensitive cells is discussed with reference to various theories of the evolution of photoreceptors.Abbreviations ax axonema - bb basal body - cc cup cell - ci cilium - cu cuticle - epc epidermal cell - g Golgi apparatus - gp glycogen particles - mi mitochondrion - mv microvilli - mvb multivesicular body - nu nucleus - pc pigment cell - pg pigment granule - rer rough ER - smc submicrovillar cysternae - sr striated rootlet     

The ontogeny of the filter apparatus of anuran larvae (Amphibia,Anura)

Summary The pharynx ofBufo calamita, Rana temporaria andBombina variegata larvae (larval Types IV and III) changes considerably during the latter part of embryonic development. The entodermal regions between the visceral pockets flatten inward to form the anlagen of the filter plates. The ectoderm thrusts forward from the area of the persistent epidermal gills overlying the anlagen of the filter plates. The esophagus pushes dorsolaterally into the pharynx to give rise to the ciliary cushions. Comparison with the development ofXenopus laevis (larval Type I) reveals shared characters: (1) the filter plates are overlapped by the sensory layer of the epiderm and (2) the ciliary grooves are, like the ciliary cushions of larval Types III and IV, anteriorly directed dorsolateral extensions of the esophagus. In all the species studied an ectodermal-esophageal filter apparatus develops. The evolutionary origin of this filter apparatus is discussed. The epidermalization of gills is suggested as a common character with the sister group of Dipnoi, and is therefore a plesiomorphic character in all amphibians. The tendency of filter plate epidermalization is considered to be the end of a process which is also indicated in the epidermalization of the first visceral pouch in lung fish. The ciliary groove is unique in anuran larvae within the Lissamphibia, and is therefore seen as an autapomorphic character within amphibians. On the basis of the different structure of the ciliary cushion inX. laevis and in the other species of this study, two alternative levels of evolutionary ciliary groove origin are discussed. Derivation from the esophagus took place: (1) in a common anuran larval ancestor, or (2) at two independent levels; the first in the Pipidae (-Rhinophrynidae) ancestor and the second in the ancestor of all the other anuran families. Several larval characters and cladistic aspects make the first alternative more probable than the second. Larval Type II anatomy and Larval Type II truncation from the Larval Type IV of Ranoidea do not contradict these considerations. There is disproportionately early commencement of ingestion activity inR. temporaria (G Stage 23),B. calamita (G Stage 23), andB. bufo (G Stage 24) compared toXenopus. Feeding in the former three species precedes the differentiation of the filter plates, their mucus production, and the exhaustion of the yolk supply in the gut tissue. By contrast, the goblet cells and the ciliary cells of the ciliary cushions are already differentiated when feeding starts. This suggests that ingestion in these early stages requires mucus production by the ciliary cushions and transport by their ciliary cells. Presumably in fully formed larvae, the ciliary cushions are the mucus donors, whereas the filter plates are the mucus depositors. By contrast,X. laevis does not begin active food intake by suspension feeding until after the yolk supply has been used up from the entoderm of the buccal cavity to deep in the esophagus.Abbreviations AAC anlage of apical cell - AC apical cell - ACE anlage of cerebrum - ACG anlage of ciliary groove - AD aorta dorsalis - ADV anlage of dorsal velum - AG anlage of glottis - AFP anlage of filter plates - AFR anlage of filter rows - AFPC anlage of epidermal fold of peribranchial chamber (anlage of operculum) - ant. anterior - AMF anlage of middle fold - AO adhesive organ - APEG anlage of persistent epidermal gills - APOP anlage of postnarial papilla - APSF anlage of primary side fold - ASC1 anlage of Type 1 secretory cell - ATE anlage of tuba Eustachii - ATEG anlage of transient epidermal gills - AVV anlage of ventral velum - B branchial arch - BI-IV branchial arches I–IV - BFA buccal floor arena - BFT branchial food trap - BL basal lamina - BRA buccal roof arena - C cilium, cilia - CA cartilage of visceral arch - CC ciliary cushion - CE cerebrum, brain - CG ciliary groove - CH choana - CHY ceratohyale - CIC ciliary cell - CL capillary vessel - CN centriole, basal body - COC cuboidal cells - CT connective tissue - CTC connective tissue cell - d dorsal - DV dorsal velum - DVI–III dorsal vela I–III - E esophagus - e early - ED edge of filter plate - EN endothelium - ENC entodermal cell - EP epiderm - EPC epidermal cell - ER endoplasmatic reticulum - ET erythrocyte - ETZ ectodermal-entodermal transition zone - EV ear vesicle - EX merocrine extrusion - EY eye - EZ zone of extrusion - FP filter plate - FPII filter plate of the 2nd branchial arch - FPIV filter plate of the 4th branchial arch - FPC epidermal fold of peribranchial chamber (operculum) - FC filter cavity - FN filter niche - FR filter row - GL glottis - GS gill slit - 1. GS first gill slit - GZ glandular zone - H heart - HP hypobranchial plate - HY hyoid arch - IC intercellular space, enlarged by fixation and dehydration - L late - LJ lower jaw - LT larval type - LV lipid vacuole - M mitochondrion - MA mandibular arch - MF middle fold - med. median - MS microvillous stubs - MZ zone of microtubes - NAC nucleus of apical cell - NCIC nucleus of ciliary cell - NCL nucleus of capillary vessel - NCOC nucleus of cuboidal cells - NCT nucleus of connective tissue - NENC nucleus of entodermal cell - NEPC nucleus of epidermal cell - NO external nares - NPEC nucleus of periderm cell - NRC nucleus of random cell - NSC1 nucleus of Type 1 secretory cell - NSC3 nucleus of Type 3 secretory cell - NSLC nucleus of sensory layer cell - NSPC nucleus of supporting cell - NSQC nucleus of squamous epithelial cell - OC oral cavity - OS mouth - P papilla - PC peribranchial chamber - PCW peribranchial chamber wall - PE periderm - PEC periderm cell - PEG persistent epidermal gill - PG pigment granule - post. posterior - PS primary side fold - PH pharynx - RC random cell - RO rootlet - SC1 Type 1 secretory cell - SC2 Type 2 secretory cell, goblet cell - SC3 Type 3 secretory cell - SC4 Type 4 secretory cell - SG secretory groove - SL sensory layer - SLC sensory layer cell - SP secretory pit - SPC supporting cell - SQC squamous epithelial cell - SR secretory ridge - SRC secretory ridge cell - SS secondary side fold - ST. stage - STD stomodeum - SU spiculum of hypobranchial plate - T tentacle - TA anlage of tongue - TEG transient epidermal gill - TZ transitional zone of branchial food trap and ventral velum - UJ upper jaw - v ventral - VA visceral arch - VC vacuole - VPI–IV visceral pockets I–IV - VP visceral pocket - VV ventral velum - YV yolk vacuoles Supported by the Deutsche Forschungsgemeinschaft (DFG)     

On the three visual pigments in the retina of the firefly squid,Watasenia scintillans

Summary The deep-sea bioluminescent squid, Watasenia scintillans, has three visual pigments: The major one (A1 pigment) is based on retinal and has _max = 484 nm, the second one (A2 pigment) is based on 3-dehydroretinal and has _max = 500 nm, and the third one (A4 pigment) is based on 4-hydroxyretinal and has _max = 470 nm. The distribution of these 3 visual pigments in the retina was studied by HPLC analysis of the retinals in retina slices obtained by microdissection. It was found that A1 pigment was not located in the specific region of the ventral retina receiving the down-welling light which contains very long photoreceptor cells, forming two strata. A2 and A4 pigment were found exclusively in the proximal pinkish stratum and in the distal yellowish stratum. The role of these pigments in the retina is hypothesized to involve spectral discrimination. The extraction and analysis of retinoids to determine the origin of 3-dehydroretinal and 4-hydroxyretinal in the mature squid showed only a trace amount of 4-hydroxyretinol in the eggs. Similar analysis of other cephalopods collected near Japan showed the absence of A2 or A4 pigment in their eyes.Abbreviations HPLC high-performance liquid chromatography - IS inner segment - OS outer segment     

Growth and pigment production byArthrobacter pyridinolis n. sp.

A new bacterium capable of growing on 2-hydroxypyridine as sole source of carbon and nitrogen was isolated from soil. During its growth on solid medium, approximately 50% of this substrate was converted to a brilliant blue crystalline pigment which was deposited extracellularly in the colony mass. The pigment was identical to that produced byArthrobacter crystallopoietes during its growth on 2-hydroxypyridine. The new isolate exhibited the typical cycle of morphogenesis characteristic of the genusArthrobacter. The organism is different from all other reported species ofArthrobacter. It is proposed that the organism be namedArthrobacter pyridinolis n. sp.List of Abbreviations MSP mineral salts phosphate basal culture medium containing 2-hydroxypyridine, yeast extract and trace salts - 2-HP 2-hydroxypyridine - PFU plaque forming units - G+C guanine+cytosine - T _m midpoint of thermal denaturation     

Metabolic products of microorganisms. 185. The anthraquinones of the Aspergillus glaucus group. I. Occurrence,isolation, identification and antimicrobial activity

The occurrence of emodin, erythroglaucin, physcion, physcion-9-anthrone, questin, catenarin, and catenarin-8-methyl ether in different species of the Aspergillus glaucus group (genus Eurotium) was investigated. So far catenarin-8-methyl ether (1, 4, 6-trihydroxy-8-methoxy-3-methylanthraquinone) has not been described as a natural product; it was therefore given the name rubrocristin. The chemical and physical properties of rubrocristin are reported. In addition a new violet pigment (C₁₆H₁₂O₅) was isolated and characterized by its MS-, IR- and UV-spectra.The antimicrobial properties of all substances were examined in the agar diffusion assay. Gram-positive bacteria were the most sensitive organisms and catenarin was the most active naturally occurring substance. Synthetically obtained 1, 4, 6, 8-tetrahydroxy-anthraquinone was slightly more active than catenarin, whereas rubrocristin showed no antibacterial activity.Abbreviations MIC Minimal inhibitory concentration - TLC Thin layer chromatography - PTLC Preparative thin layer chromatography Metabolic products of microorganisms. 184. H. Anke: On the mode of action of cladosporin. J. Antibiotics 32, 952–958 (1979)     

Caste-specific modulation of juvenile hormone III content and ecdysteroid titer in postembryonic development of the stingless bee,Scaptotrigona postica depilis

Summary Juvenile hormone III content and ecdysteroid titer were analyzed for larval and pupal development of the stingless bee,Scaptotrigona postica depilis. Castespecific differences in juvenile hormone III content were detected at three developmental phases: at the transition from the fourth to the fifth larval stadium, in the spinning phase of the fifth larval stadium, and shortly after the imaginal moult. During the fifth larval stadium, juvenile hormone content closely reflects corpora allata activity. Juvenile hormone synthesis may thus be responsible for the elevated hormone titer in spinning-phase queen larvae, a phase of known sensitivity for induction of queen characters by exogenous juvenile hormone. For ecdysteroids, two phases of caste-specific differences were found: in the pre-pupal phase, and shortly after the imaginal moult. In both periods the titer in queens is distinctly higher compared to workers.Abbreviations Im imago 1 day after eclosion - L3, L4, L5 larval instars 3, 4, and 5 - L5F1, L5F2 substages of feeding phase in fifth larval instar - L5S1, L5S2, L5S3 substages of spinning phase in fifth larval instar - PP1, PP2 substages of prepupal phase - Pw white eyed pupa - Pp pink eyed pupa - Pr red eyed pupa - Pd dark eyed pupa - Pdl, Pdm, Pdd dark eyed pupa with progressive tanning of cuticle - RIA radioimmunoassay     

Comparative analysis of the composition of two chlorophyll-b-containing light-harvesting complexes

The major light-harvesting complexes from Mantoniella squamata (Prasinophyceae) and from Chlorella fusca (Chlorophyceae) were analyzed with respect to polypeptide composition and pigmentation. It was found that the polypeptides of Mantoniella are smaller than those of Chlorella and bind twice the amount of pigment. We assume that the amount of pigment per polypeptide is of ecological as well as of taxonomical importance.Abbreviations Chl chlorophyll - LHC light-harvesting complex - Xan xanthophyll We thank the support by the Deutsche Forschungsgemeinschaft.     

Photoreceptors with mitochondrial lenses inPogaina suecica (Plathelminthes,Rhabdocoela)

Summary The photoreceptors ofPogaina suecica correspond to the type of pigment cup ocelli. Each eye consists of one cup cell and three sensory cells. The most conspicuous differentiations of these eyes are lens elements formed by giant mitochondria densely filled with homogeneous electron-dense material. From electron microscopical findings available to date it is hypothesized that mitochondrial lensing might be an autapomorphy of a taxon comprising the Provorticidae Kirgisellinae, Dalyelliidae and Graffillidae groups which are ascribed to the paraphyletic Dalyellioida.Abbreviations l _1–3 lenses - npc nucleus of the pigment cell - pc pigment cell - pg pigment granule - rh rhabdomeres - sc _1–3 sensory cells     

Post-embryonic development of circadian rhythm in the cricket,Gryllus bimaculatus: A rhythm reversal

Summary Locomotor activity of the male cricketGryllus bimaculatus DeGeer was recorded from the 7th or last (8th) instar nymph. The nymph showed a diurnal rhythm (nymphal rhythm = NR), while the adult, on the contrary, was nocturnal (adult rhythm = AR) (Fig. 1). This rhythm reversal occurred suddenly 3 to 5 days after the imaginal molt, almost simultaneously with the first spermatophore formation and the start of stridulation (calling song) (Fig. 2). In addition to the antiphase relationship, both rhythms also differed in the freerunning period (tau) and wave form. Tau_scdd was significantly longer in NR (24.33 h) than in AR (23.91 h) (Fig. 3). AR was characterized by a sharp activity peak in each cycle, which NR, however, lacked (Fig. 1, 3, 6). On the basis of these differences, two possibilities are discussed; one is that NR and AR are separate oscillations and the other is that both are coupled to different phase points of one oscillation.Abbreviations LD light dark - DD constant darkness - LL constant light - NR nymphal rhythm - AR adult rhythm     

Biosynthesis and cytoplasmic accumulation of a chlorinated catechol pigment during 3-chlorobenzoate aerobic co-metabolism in Pseudomonas fluorescens

A strain of Pseudomonas fluorescens was capable of co-metabolizing 3-chlorobenzoic acid with the production of a chlorinated catechol black pigment. A peroxidase and another enzymatic activity referred to as a polyphenol oxidase were found to be involved in the oxidation of 4-chlorocatechol to 4-chloro-1,2-benzoquinone, i.e. in the production of highly reactive substrates for pigment formation. Therefore, P. fluorescens cells were seen to take an active part not only in 3-chlorobenzoate mineralization but also in overall pigment production. pH was found to be a key parameter in the regulation of the activity of P. fluorescens oxidoreductive enzymes. Ultrastructural investigations showed that electron dense granules of pigment were distributed throughout the cytoplasm of Pseudomonas fluorescens cells grown in presence of 3-chlorobenzoate, as confirmed also by Thiéry cytochemical investigations.In these cells, an extensive contraction of the cytoplasm as well as a significant damage to the cell wall after two days of incubation, suggested that pigment production caused a premature death of the cells accompanied by the leakage of the cell content. Pigment production seemed to occur mostly in the cytoplasmic context where the electron dense material accumulates until it is released in the medium after the cell lysis.Abbreviations 3-CBA 3-chlorobenzoic acid - BA benzoic acid - 4-CC 4-chlorocatechol - 3-CC 3-chlorocatechol - MBTH 3-methyl-2-benzothiazolinone hydrazone - l-DOPA l-3,4-dihydroxyphenyl-alanine - SPB sodium phosphate buffer     

Mechanisms of black and white stripe pattern formation in the cuticles of insect larvae

Molecular mechanisms that produce pigment patterns in the insect cuticle were studied. Larvae of the armyworm Pseudaletia separata have stripe patterns that run longitudinally along the body axis. The pattern in the cuticle became clear by being emphasized by the increasing contrast between the black and white colors of the lines after the last larval molt. We demonstrated that dopa decarboxylase (DDC) mRNA as well as protein are expressed specifically in the epidermal cells under the black stripes. The pigmentation on the stripes was clearly diminished by injection of a DDC inhibitor (m-hydroxybenzylhydrazine) to penultimate instar larvae for 1 day before molting, suggesting that DDC contributes to the production of melanin. Further, electron microscopic observation showed that the epidermal cells under the gap cuticle region (white stripe) between the black stripes contain many uric acid granules, which gives a white color. Our findings suggest that the spatially regulated expression of DDC in the epidermal cells produces the black stripes while abundant granules of uric acid in the cells generate the white stripes in the cuticle. Based on these results, we concluded that this heterogeneity in the epidermal cells forms cuticular stripe patterns in the armyworm larvae.     

Ocelli in a Cnidaria polyp: the ultrastructure of the pigment spots in Stylocoronella riedli (Scyphozoa,Stauromedusae)

Within the Cnidaria, the occurrence of ocelli at the polyp stage is only known in the species of Stylocoronella (Scyphozoa, Stauromedusae). The light-sensitive organs of S. riedli are ultrastructurally investigated. In this interstitial-living species, each of the up to 24 ocelli is composed of between seven and nine monociliary sensory cells and between one and four pigment cells. A striking feature of the photoreceptive cilia is their peculiar axonemal pattern. This is expressed (a) by the presence of a third central microtubule at a certain point and (b) by the balloon-like swelling of the distal portion of the cilium, with clearly scattered microtubules in this area. Although the polyps of S. riedli show no distinct reaction to light stimuli, the ultrastructural results corroborate the hypothesis that these organs are light-sensitive organs. The possible function of the pigment granules is discussed.Abbreviations bb basal body - c cilium - co collar - csv crescent-shaped vesicle - cv clear vesicle - dcv dense-core vesicles - k kinetosome - m mitochondrion - mvb multivesicular body - n nucleus - oc ocellus - pc piment cell - pg pigment granule - sc sensory cell - sr striated rootlet - v vesicle     

Identification of the spI products of Balbiani ring genes in Chironomus thummi

The spI fraction of high molecular weight secretory proteins was analysed in Chironomus thummi. These proteins are encoded by giant Balbiani ring (BR) genes which develop specifically in salivary gland cells. Each component of the spI fraction was studied electrophoretically from early and middle 4th instar larvae and prepupae, as well from galactose-treated larvae where changes in the relative puffing pattern of BR1 and BR2 are known to occur. The spI fraction consists of at least two bands with electrophoretic mobilities slower than those of the spI components of Camptochironomus. The slow migrating component remains throughout the 4th larval instar, while the amount of the faster component changes, being abundant in early 4th instar and prepupae, but not present (or very weak) in middle 4th instar. The correlated shifts in BR puffing pattern during these developmental stages suggest that the slow and fast components are encoded by BR2 and BR1. The spI fraction is modified by galactose treatment, the fast component being induced in parallel with a decrease in the slow component. These changes are correlated with changes in the steady-state levels of RNA: an increase in BR1 RNA and a decrease in BR2 RNA, and of proteins. These proteins could correspond to the spIb and spIa fractions allocated to BR2 and BR1, respectively, in Camptochironomus. After galactose treatment a new faster band sometimes appears, that could correspond to the spIc fraction of Camptochironomus. A possible spId equivalent was also identified. In conclusion the main features of the spI family in C. thummi are similar to those of spI in Camptochironomus.Abbreviations BR Balbiani ring - spI family of M_r=10⁶ secretory polypeptides     

Structure and development of the larval central complex in a holometabolous insect,the beetle Tenebrio molitor

Summary The neuroarchitecture of the central complex, a prominent neuropil in the midbrain of the holometabolan, Tenebrio molitor, is described throughout larval development. The analysis is based on classical silver impregnations and on fate-mapping of identified neurons using antisera against serotonin and FMRF-amide. In T. molitor, the central body is present in the first larval instar, and is formed by side branches of contralaterally projecting neurons. Glial cells surround eight neuropil compartments in the first larval instar. These subdivisions in the organization of the fan-shaped body are maintained throughout development. Intrinsic interneurons are found from the 5th larval instar onwards. In the last larval stage, the central complex consists of the fan-shaped body, the protocerebral bridge, and the anlage of the ellipsoid body. The cellular architecture of the fan-shaped body of the last larval instar resembles the basic structural characteristics of the adult. Serotonin-immunoreactive neurons and FMRF-amide immunoreactive neurons in the midbrain of the first larval instar show the basic structural features of the respective imaginal cells. The structural organizations of larval and adult midbrain are compared.Abbreviations a Anterior - AGT antenno-glomerular tract - aL -lobus - AL antennal lobe - AP anterior protocerebrum - bL -lobe - BSN bilateral symmetrical - FMRF amide-immunopositive neurons - CA calyx - CL1-CL4 serotonin-immunopositive neurons cluster 1–4 - d dorsal - DAB diaminobenzidine tetrahydrochloride - DC dorsal commissure - DCFB dorsal commissure of the fan-shaped body - DHT dorsal horizontal tract - DLTR dorsal lateral triangle - DMLP dorsal medial lateral protocerebrum - DN serotonin-immunopositive deuterocerebral neuron - EB ellipsoid body - en1, en2 extrinsic neurons connecting two FB-subcompartments - esn extrinsic subcompartmental neuron - l lateral - FB fan-shaped body - FN serotonin-immunopositive fan-shaped neuron - fs1, fs2 fanshaped neurons of type 1 and 2 - GC great commissure - HF horizontal fibres - in intrinsic neuron connecting two FB-subcompartments - isn intrinsic subcompartmental neuron - IT isthmus tract - LF large-field neurons - LFASC lateral fascicle - LMFASC lateral median fascicle - MB median bundles - MLP medial lateral protocerebrum - p posterior - P pedunculus - PB protocerebral bridge - pb-fb protocerebral bridge-fan-shaped body connection - PBS phosphate-buffered saline - PDC posterio-dorsal commissure - PTX phosphate-buffered saline containing Triton X-100 - SU suboesophageal ganglion - SVT small ventral triangles - TN 1,2 tritocerebral serotonin-immunoreactive neuron 1,2 - v ventral - VB ventral body - VBC ventral body commissure - VCBC ventral central body commissure - VCFB ventral commissure of the fan-shaped body     

The ultrastructure of the eyes in the veliger-larvae of Aporrhais sp. and Bittium reticulatum (Mollusca,Caenogastropoda)

Summary The cerebrally innervated larval eyes of Aporrhais sp. and Bittium reticulatum are investigated by means of transmission electron microscopy. Each organ consists of a pigmented cup containing an acellular lens. The cornea overlaps the anterior portion of the eye. The retina is composed of sensory cells and supportive cells. The sensory cells of Aporrhais sp. bear one cilium and in Bittium reticulatum two cilia, the ciliary membrane being folded into numerous finger-shaped evaginations. The supportive cells contain the pigment granules and most of them bear one or two cilia, the plasmalemma of which is likewise folded. It is supposed that: (a) these cilia have a transportive function for lens material and (b) that the ciliary photoreceptor of Aporrhais sp. and Bittium reticulatum is a functional adaptation to a relatively long larval period.Abbreviations bb basal body - bp basal plate - c cilium - cc corneal cell - cm ciliary membranes - cw ciliary whorl - gd Golgi dictyosomes - gm granular material - l lens - m mitochondrion - mt microtubules - mv microvilli - mvb multivesicular body - n nucleus - pb pigment border - pg pigment granule - rer rough endoplasmic reticulum - sc sensory cell - sj septate junctions - spc supportive cell