The organochlorine insecticide 1,2,3,4,5,6-hexachlorocyclohexane (lindane) but not 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) augments the nocturnal increase in pineal N-acetyltransferase activity and pineal and serum melatonin levels

The effect of organochlorine insecticides lindane (1,2,3,4,5,6-hexachlorocyclohexane) and DDT (1,1,1-trichloro-2,2-bis (p-chlorophenyl)ethane) were studied in terms of their effects on the rat pineal N-acetyltransferase (NAT) activity, hydroxyindole-O-methyltransferase (HIOMT) activity and pineal and serum melatonin levels during the day (2000h) and at night (2300 and 0100h). Additionally, pineal levels of 5-hydroxytryptophan (5-HTP), serotonin (5-HT), and 5-hydroxyindole acetic acid (5-HIAA) were estimated. Nocturnal NAT activity was increased after lindane administration; likewise, lindane augmented pineal and serum melatonin levels at 2300h. Conversely, DDT was without a statistically significant effect on either NAT activity or on pineal or serum melatonin levels. Neither lindane nor DDT significantly influenced pineal HIOMT values either during the day or at night. Likewise, neither insecticide consistently influenced pineal levels of either 5-HTP, 5-HT or 5-HIAA. The results indicate that the organochlorine insecticide, lindane, modifies pineal melatonin synthesis in vivo.     

A cytogenetic study on human intestinal trematodes of the genus Metagonimus (Digenea: Heterophyidae) in Korea

In order to analyze chromosome numbers and karyotypes of intestinal trematodes belonging to the genus, Metagonimus, the gonad tissues of M. takahashii, M. miyatai, and M. yokogawai were prepared and examined. The number of bivalents in the first meiotic division of M. takahashii was nine (n = 9). The diploid number of M. miyatai was observed to be eighteen (2n = 18) and their chromosomes consisted of one pair of metacentric, 7 pairs of submetacentric, and one pair of telocentric chromosomes. The diploid number of M. yokogawai was thirty-two (2n = 32) and the chromosome complements were composed of two pairs of metacentric, 11 pairs of submetacentric, and three pairs of subtelocentric chromosomes. These results could be a supporting evidence for the validity of the new species, M. miyatai, distinct from M. yokogawai.     

Neural Regulation of Dark-Induced Abundance of Arylalkylamine N-Acetyltransferase (AANAT) and Melatonin in the Carp (Catla catla) Pineal: An In Vitro Study

In all the vertebrates, synthesis of melatonin and its rhythm-generating enzyme arylalkylamine N-acetyltransferase (AANAT) reaches its peak in the pineal during the night in a daily light-dark cycle, but the role of different neuronal signals in their regulation were unknown for any fish. Hence, the authors used specific agonist and antagonists of receptors for different neuronal signals and regulators of intracellular calcium (Ca²⁺) and adenosine 3',5'-cyclic monophosphate (cAMP) in vitro to study their effects on the abundance of AANAT and titer of melatonin in the carp (Catla catla) pineal. Western blot analysis followed by quantitative analysis of respective immunoblot data for AANAT protein, radioimmunoassay of melatonin, and spectrophotometric analysis of Ca²⁺ in the pineal revealed stimulatory effects of both adrenergic (α₁ and β₁) and dopaminergic (D₁) agonists and cholinergic (both nicotinic and muscarinic) antagonists, inhibition by both adrenergic and dopaminergic antagonists and cholinergic agonists, but independent of the influence of any agonists or antagonists of α₂-adrenergic receptors. Band intensity of AANAT and concentration of melatonin in the pineal were also enhanced by the intracellular calcium-releasing agent, activators of both calcium channel and adenylate cyclase, and phophodiesterase inhibitor, but suppressed by inhibitor of calcium channel and adenylate cyclase as well as activator of phophodiesterase. Moreover, an inhibitory effect of light on the pineal AANAT and melatonin was blocked by both cAMP and proteasomal proteolysis inhibitor MG132. Collectively, these data suggest that dark-induced abundance of AANAT and melatonin synthesis in the carp pineal are a multineuronal function, in which both adrenergic (α₁ and β₁, but not α₂) and dopaminergic signals are stimulatory, whereas cholinergic signals are inhibitory. This study also provides indications, though arguably not conclusive evidence, that in either case the neuronal mechanisms follow a signal-transduction pathway in which Ca²⁺ and cAMP may act as the intracellular messengers. It also appears that proteasomal proteolysis is a conserved event in the regulation of AANAT activity in vertebrates. (Author correspondence: dgp_skmaitra@yahoo.co.in)     

Interaction of Leptomonas wallacei with the intestinal tract of its natural host Oncopeltus fasciatus (Hemiptera: Lygaeidae)

While investigating the distribution of Leptomonas wallacei in the intestine of the insect host Oncopeltus fasciatus, promastigotes and cyst-like forms of L. wallacei were observed only in the midgut ventricles V(3) and V(4) and the hindgut. In video-microscopy, once contact had occurred, the parasites remained attached to the midgut epithelium. Scanning electron microscopy revealed the adhesion of flagellates and cyst-like forms to the midgut wall and to the rectal pads of the hindgut. Using transmission electron microscopy, we observed that adhesion occurred mainly between the flagellum and the perimicrovillar membranes secreted by the midgut epithelium. No modifications were observed either in the parasite or in the epithelial cells. In the hindgut, adhesion to the superficial wax layer of the epithelial cells of the rectal pads was via flagellum. Host cell morphology appeared unaffected by L. wallacei.     

Detoxication of structurally diverse polycyclic aromatic hydrocarbon (PAH) o-quinones by human recombinant catechol-O-methyltransferase (COMT) via O-methylation of PAH catechols

Polycyclic aromatic hydrocarbons (PAH) are environmental and tobacco carcinogens. Metabolic activation of intermediate PAH trans-dihydrodiols by aldo-keto reductases (AKRs) leads to the formation of electrophilic and redox-active o-quinones. We investigated whether O-methylation by human recombinant soluble catechol-O-methyltransferase (S-COMT) is a feasible detoxication step for a panel of structurally diverse PAH-catechols produced during the redox-cycling process. Classes of PAH non-K-region o-quinones (bay region, methylated bay region, and fjord region o-quinones) produced by AKRs were employed in the studies. PAH o-quinones were reduced to the corresponding catechols by dithiothreitol under anaerobic conditions and then further O-methylated by human S-COMT in the presence of S-[3H]adenosyl-l-methionine as a methyl group donor. The formation of the O-methylated catechols was detected by HPLC-UV coupled with in-line radiometric detection, and unlabeled products were also characterized by LC-MS/MS. Human S-COMT was able to catalyze O-methylation of all of the PAH-catechols and generated two isomeric metabolites in different proportions. LC-MS/MS showed that each isomer was a mono-O-methylated metabolite. 1H NMR was used to assign the predominant positional isomer of benzo[a]pyrene-7,8-catechol as the O-8-monomethylated catechol. The catalytic efficiency (k(cat)/K(m)) varied among different classes of PAH-catechols by 500-fold. The ability of S-COMT to produce two isomeric products from PAH-catechols was rationalized using the crystal structure of the enzyme. We provide evidence that O-8-monomethylated benzo[a]pyrene-7,8-catechol is formed in three different human lung cell lines. It is concluded that human S-COMT may play a critical role in the detoxication of PAH o-quinones generated by AKRs.     

Distribution and biological role of the oligopeptide-binding protein (OppA) in Xanthomonas species

In this study we investigated the prevalence of the oppA gene, encoding the oligopeptide binding protein (OppA) of the major bacterial oligopeptide uptake system (Opp), in different species of the genus Xanthomonas. The oppA gene was detected in two Xanthomonas axonopodis strains among eight tested Xanthomonas species. The generation of an isogenic oppA-knockout derivative of the Xac 306 strain, showed that the OppA protein neither plays a relevant role in oligopeptide uptake nor contributes to the infectivity and multiplication of the bacterial strain in leaves of sweet orange (Citrus sinensis) and Rangpur lime (Citrus limonia). Taken together these results suggest that the oppA gene has a recent evolutionary history in the genus and does not contribute in the physiology or pathogenesis of X. axonopodis.     

Austropeplea ollula (Pulmonata: Lymnaeidae): a new molluscan intermediate host of a human intestinal fluke, Echinostoma cinetorchis (Trematoda: Echinostomatidae) in Korea

Three freshwater snail species of the family Lymnaeidae have been reported from Korea, Radix auricularia coreana, Austropeplea ollula and Fossaria truncatula. Out of 3 lymnaeid snail species, A. ollula was naturally infected with the Echinostoma cinetorchis cercariae (infection rate = 0.7%). In the experiments with the laboratory-bred snails, F. truncatula as well as A. ollula was also susceptible to the E. cinetorchis miracidia with infection rates of 25% and 40%, respectively. All of three lymnaeid snail species exposed to the E. cinetorchis cercariae were infected with the E. cinetorchis metacercariae. It is evident that A. ollula acts as the first molluscan intermediate host of E. cinetorchis in Korea, and F. truncatula may be a possible candidate for the first intermediate host of this intestinal fluke. Also, three lymnaeid snail species targeted were experimentally infected with E. cinetorchis metacercariae.     

The role of surfactant protein D in the colonisation of the respiratory tract and onset of bacteraemia during pneumococcal pneumonia

We have shown previously that surfactant protein D (SP-D) binds and agglutinates Streptococcus pneumoniae in vitro. In this study, the role of SP-D in innate immunity against S. pneumoniae was investigated in vivo, by comparing the outcome of intranasal infection in surfactant protein D deficient (SP-D-/-) to wildtype mice (SP-D+/+). Deficiency of SP-D was associated with enhanced colonisation and infection of the upper and lower respiratory tract and earlier onset and longer persistence of bacteraemia. Recruitment of neutrophils to inflammatory sites in the lung was similar in both strains mice in the first 24 hrs post-infection, but different by 48 hrs. T cell influx was greatly enhanced in SP-D-/- mice as compared to SP-D+/+ mice. Our data provides evidence that SP-D has a significant role to play in the clearance of pneumococci during the early stages of infection in both pulmonary sites and blood.     

The role of the persistent fruit wall in seed water regulation in Raphanus raphanistrum (Brassicaceae)

Background and Aims

Dry fruits remain around the seeds at dispersal in a number of species, especially the Brassicaceae. Explanations for this vary, but usually involve mechanisms of innate dormancy. We speculate that, instead, a persistent fruit may give additional protection through control of dehydration, to species growing in arid or Mediterranean environments where water is sporadic.

Methods

X-rays and weight measurements were used to determine the extent to which Raphanus raphanistrum seeds within mature fruits imbibe water, and germination tests determined the roles of the fruit and seed coat in seed dormancy. Rates of water uptake and desiccation, and seedling emergence were compared with and without the fruit. Finally, germinability of seeds extracted from fruits was determined after various periods of moist conditions followed by a range of dry conditions.

Key Results

Most seeds rapidly take up water within the fruit, but they do not fully imbibe when compared with naked seeds. The seed coat is more important than the dry fruit wall in maintaining seed dormancy. The presence of a dry fruit slows emergence from the soil by up to 6–8 weeks. The fruit slows the rate of desiccation of the seed to a limited extent. The presence of the fruit for a few days during imbibition somehow primes more seeds to germinate than if the fruit is absent; longer moist periods within the pod appear to induce dormancy.

Conclusions

The fruit certainly modifies the seed environment as external conditions change between wet and dry, but not to a great extent. The major role seems to be: (a) the physical restriction of imbibition and germination; and (b) the release and then re-imposition of dormancy within the seed. The ecological significance of the results requires more research under field conditions.     

The repetitive component of the A genome of peanut (Arachis hypogaea) and its role in remodelling intergenic sequence space since its evolutionary divergence from the B genome

Background and Aims

Peanut (Arachis hypogaea) is an allotetraploid (AABB-type genome) of recent origin, with a genome of about 2·8 Gb and a high repetitive content. This study reports an analysis of the repetitive component of the peanut A genome using bacterial artificial chromosome (BAC) clones from A. duranensis, the most probable A genome donor, and the probable consequences of the activity of these elements since the divergence of the peanut A and B genomes.

Methods

The repetitive content of the A genome was analysed by using A. duranensis BAC clones as probes for fluorescence in situ hybridization (BAC-FISH), and by sequencing and characterization of 12 genomic regions. For the analysis of the evolutionary dynamics, two A genome regions are compared with their B genome homeologues.

Key Results

BAC-FISH using 27 A. duranensis BAC clones as probes gave dispersed and repetitive DNA characteristic signals, predominantly in interstitial regions of the peanut A chromosomes. The sequences of 14 BAC clones showed complete and truncated copies of ten abundant long terminal repeat (LTR) retrotransposons, characterized here. Almost all dateable transposition events occurred <3·5 million years ago, the estimated date of the divergence of A and B genomes. The most abundant retrotransposon is Feral, apparently parasitic on the retrotransposon FIDEL, followed by Pipa, also non-autonomous and probably parasitic on a retrotransposon we named Pipoka. The comparison of the A and B genome homeologous regions showed conserved segments of high sequence identity, punctuated by predominantly indel regions without significant similarity.

Conclusions

A substantial proportion of the highly repetitive component of the peanut A genome appears to be accounted for by relatively few LTR retrotransposons and their truncated copies or solo LTRs. The most abundant of the retrotransposons are non-autonomous. The activity of these retrotransposons has been a very significant driver of genome evolution since the evolutionary divergence of the A and B genomes.     

Expression of UDP-N-acetyl-D-galactosamine: polypeptide N-acetylgalactosaminyltransferase-6 in gastric mucosa, intestinal metaplasia, and gastric carcinoma

Aberrant mucin O-glycosylation is often observed in cancer and is characterized by the expression of immature simple mucin-type carbohydrate antigens. UDP-N-acetyl-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase-6 (ppGalNAc-T6) is one of the enzymes responsible for the initial step in O-glycosylation. This study evaluated the expression of ppGalNAc-T6 in human gastric mucosa, intestinal metaplasia, and gastric carcinomas. Our results showed that ppGalNAc-T6 is expressed in normal gastric mucosa and in intestinal metaplasia. A heterogeneous expression and staining pattern for this enzyme was observed in gastric carcinomas. ppGalNAc-T6 was expressed in 79% of the cases, and its expression level was associated with the presence of venous invasion. Our results provide evidence that ppGalNAc-T6 is an IHC marker associated with venous invasion in gastric carcinoma and may contribute to the understanding of the molecular mechanisms that underlie aberrant glycosylation in gastric carcinogenesis and in gastric carcinoma.     

Association between the dopamine D4 receptor gene exon III variable number of tandem repeats and political attitudes in female Han Chinese

Twin and family studies suggest that political attitudes are partially determined by an individual''s genotype. The dopamine D4 receptor gene (DRD4) exon III repeat region that has been extensively studied in connection with human behaviour, is a plausible candidate to contribute to individual differences in political attitudes. A first United States study provisionally identified this gene with political attitude along a liberal–conservative axis albeit contingent upon number of friends. In a large sample of 1771 Han Chinese university students in Singapore, we observed a significant main effect of association between the DRD4 exon III variable number of tandem repeats and political attitude. Subjects with two copies of the 4-repeat allele (4R/4R) were significantly more conservative. Our results provided evidence for a role of the DRD4 gene variants in contributing to individual differences in political attitude particularly in females and more generally suggested that associations between individual genes, and neurochemical pathways, contributing to traits relevant to the social sciences can be provisionally identified.     

A new species of plasmodiidae (Coccidia: Hemosporidia) from the blood of the skink Scincus hemprichii (Scincidae: Reptilia) in Saudi Arabia

Fallisia arabica n. sp. was described from peripheral blood smears of the Skink lizard, Scincus hemprichii from Jazan Province in the southwest of Saudi Arabia. Schizogony and gametogony take place within neutrophils in the peripheral blood of the host. Mature schizont is rosette shaped 17.5 ± 4.1 × 17.0 ± 3.9 μm, with a L/W ratio of 1.03(1.02–1.05) μm and produces 24(18–26) merozoites. Young gametocytes are ellipsoidal, 5.5 ± 0.8 × 3.6 ± 0.5 μm, with a L/W of 1.53(1.44–1.61) μm. Mature macrogametocytes are ellipsoidal, 9.7 ± 1.2 × 7.8 ± 1.0 μm, with a L/W of 1.24(1.21–1.34) μm and microgametocytes are ellipsoidal, 7.0 ± 1.1 × 6.8 ± 0.9 μm. with a L/W of 1.03(1.01–1.10) μm. In comparison to the described Fallisia species, this new taxon has rosette schizonts and is larger than F. dominicensis, in Hispaniola, F. bipocrati, F. poecilopi, in Panama, F. thecadactyli in Venezuela, and F. effusa, F. simplex, F. modesta, in Brazil. F. arabica has fewer merozoites than F. effusa, F. poecilopi, F. thecadactyli and F. siamense in Thailand. This new species has more merozoites than F. dominicensis and F. modesta. All of these species belong to diverse saurian families (Agamidae, Gekkonidae, Polychrotidae, Scincidae and Teiidae) parasitize only thrombocytes or lymphocytes and some species parasitize immature erythroid cells and leucocytes.     

A revision of the Chinese Trigonalyidae (Hymenoptera,Trigonalyoidea)

The Chinese fauna of the family Trigonalyidae Cresson, 1887, is revised, keyed and fully illustrated for the first time. Eight genera of this family (Bakeronymus Rohwer, 1922, Bareogonalos Schulz, 1907, Jezonogonalos Tsuneki, 1991, re-instated, Lycogaster Shuckard, 1841, Orthogonalys Schulz, 1905, Pseudogonalos Schulz, 1906, Taeniogonalos Schulz, 1906 and Teranishia Tsuneki, 1991) are recorded from China. The genus Ischnogonalos Schulz, 1907, is synonymized with Taeniogonalos Schulz, 1906. In total 40 valid species are recognized. Twenty species are new for science: Jezonogonalos elliptifera sp. n., J. jiangliae sp. n., J. luteata sp. n., J. nigrata sp. n., Lycogaster angustula sp. n., L. flavonigrata sp. n., L. nigralva sp. n., Orthogonalys cheni sp. n., O. clypeata sp. n., O. robusta sp. n., Pseudogonalos angusta sp. n., Taeniogonalos bucarinata sp. n., T. cordata sp. n., T. geminata sp. n., T. sculpturata sp. n., T. triangulata sp. n., T. tricolorisoma sp. n., T. uncifera sp. n., Teranishia crenulata sp. n. and T. glabrata sp. n. Two species are reported new for China: Orthogonalys elongata Teranishi, 1929 and Nanogonalos flavocincta Teranishi, 1929 (renamed to Taeniogonalos subtruncata nom. n.). Seven new synonyms are proposed: Poecilogonalos yuasai Teranishi, 1938, and P. maga taiwana Tsuneki, 1991, of Taeniogonalos taihorina (Bischoff, 1914); Taiwanogonalos minima Tsuneki, 1991, and T. similis Tsuneki, 1991, of Taeniogonalos alticola (Tsuneki, 1991); P. intermedia Chen, 1949, and P. unifasciata Chen, 1949, of Taeniogonalos formosana (Bischoff, 1913). Six taxa are recognised as valid species: Bakeronymus seidakka Yamane & Terayama, 1983, Jezonogonalos laeviceps (Tsuneki, 1991), J. satoi (Tsuneki, 1991), Taeniogonalos alticola (Tsuneki, 1991), T. flavoscutellata (Chen, 1949) and T. gestroi (Schulz, 1908). Five new combinations are made: Jezonogonalos laeviceps (Tsuneki, 1991), comb. n., J. satoi (Tsuneki, 1991), comb. n., Taeniogonalos flavoscutellata (Chen, 1949), comb. n., T. gestroi (Schulz, 1908), comb. n. and T. lachrymosa (Westwood, 1874), comb. n. Lectotypes are designated for Lycogaster violaceipennis Chen, 1949, Poecilogonalos flavoscutellata Chen, 1949, P. rufofasciata Chen, 1949, and P. tricolor Chen, 1949.     

The mycetophagidae (coleoptera) of the maritime provinces of Canada

The Mycetophagidae (hairy fungus beetles) of the Maritime Provinces of Canada are surveyed. Seven species in the genera Mycetophagus, Litargus, and Typhaea are found in the region. Six new provincial records are reported including Mycetophagus punctatus and Mycetophagus flexuosus, whichare newly recorded in the Maritime Provinces. The distribution of all species is mapped, colour habitus photographs of all species are figured, and an identification key to species is provided. The discussion notes that four of the species found in the region are apparently rare, possibly due to the history of forest management practices in the region; a situation similar to that of a significant proportion of other saproxylic beetles found in the Maritime Provinces.     

The spider family Selenopidae (Arachnida, Araneae) in Australasia and the Oriental Region

We relimit and revise the family Selenopidae to include four new genera and 27 new species from Australia and the Oriental Region. The family is redefined, as are the genera Anyphops Benoit, Garcorops Corronca, Hovops Benoit, Selenops Latreille, and Siamspinops Dankittipakul & Corronca, to accommodate the new genera and to correct previous inconsistencies in the diagnoses and definitions of the aforementioned genera. The species of Selenops that occur throughout India and China are also reviewed. Three species occur in China: Selenops bursarius Karsch 1879, also known from Japan, Korea and Taiwan, Selenops ollarius Zhu, Sha, & Chen 1990, and Selenops radiatus Latreille 1819, the type of the genus and most widespread selenopid. Selenops cordatus Zhu, Sha & Chen syn. n. is recognized as a junior synonym of Selenops radiatus. Amamanganopsgen. n. is monotypic, with Amamanganops baginawasp. n. (♀; from the Philippines). Godumopsgen. n. is monotypic, with Godumops caritussp. n. (♂; from Papua New Guinea). Karaopsgen. n. occurs throughout Australia and includes 24 species. A new combination is proposed for Karaops australiensis (L. Koch 1875) comb. n. (ex. Selenops), and the new species: Karaops gangariesp. n. (♀, ♂), Karaops monteithisp. n. (♀), Karaops alanlongbottomisp. n. (♂), Karaops keithlongbottomisp. n. (♂), Karaops larryoosp. n. (♂), Karaops jarritsp. n. (♂,♀), Karaops marrayagongsp. n. (♀), Karaops ravenisp. n. (♂,♀), Karaops badgeraddasp. n. (♀), Karaops burbidgeisp. n. (♂,♀), Karaops karrawarlasp. n. (♂,♀), Karaops julianneaesp. n. (♀), Karaops martamartasp. n. (♀), Karaops manaaynsp. n. (♀, ♂), Karaops vadlaadambarasp. n. (♀, ♂), Karaops pilkingtonisp. n. (♀, ♂), Karaops deserticolasp. n. (♀), Karaops ngarutjaranyasp. n. (♂,♀), Karaops francesaesp. n. (♂,♀), Karaops toolbrunupsp. n. (♀, ♂), the type species Karaops ellenaesp. n. (♂,♀), Karaops jenniferaesp. n. (♀), and Karaops dawarasp. n. (♀).The genus Makdiopsgen. n. contains five species from India and Nepal. A new combination is proposed for Makdiops agumbensis (Tikader 1969), comb. n., Makdiops montigenus (Simon 1889), comb. n., Makdiops nilgirensis (Reimoser 1934) comb. n.,(ex. Selenops). Also, there are two new species the type of the genus Makdiops mahishasurasp. n. (♀; from India), and Makdiops shivasp. n. (♀). The genus Pakawopsgen. n. is monotypic. A new combination is proposed for Pakawops formosanus (Kayashima 1943) comb. n. (ex. Selenops), known only from Taiwan. A new combination is proposed for Siamspinops aculeatus (Simon)comb. n. (ex. Selenops). The distribution and diversity of the studied selenopid fauna is discussed. Finally, keys are provided to all of the selenopid genera and to the species of Karaopsgen. n.and Makdiopsgen. n.     

Accumulation of cadmium in near-isogenic lines of durum wheat (Triticum turgidum L. var durum): the role of transpiration

Concentrations of cadmium in the grain of durum wheat (Triticum turgidum L. var durum) are often above the internationally acceptable limit of 0.2 mg kg⁻¹. Cultivars that vary in concentrations of cadmium in the grain have been identified but the physiology behind differential accumulation has not been determined. Three pairs of near-isogenic lines (isolines) of durum wheat that vary in aboveground cadmium accumulation (8982-TL ‘high’ and ‘low’, W9260-BC ‘high’ and ‘low’, and W9261-BG ‘high’ and ‘low’) were used to test the hypothesis that the greater amounts of cadmium in shoots of the ‘high’ isolines are correlated with greater volumes of water transpired. In general, cadmium content was positively correlated with transpiration only in the ‘low’ isolines. Although shoots of the ‘high’ isolines of W9260-BC and W9261-BG contained higher concentrations of cadmium than did their corresponding ‘low’ isolines, they did not transpire larger volumes of water. In addition, isolines of 8982-TL transpired less water than did the other pairs of isolines yet both ‘high’ and ‘low’ isolines of 8982-TL contained higher amounts of cadmium than did the other pairs. The difference between ‘high’ and ‘low’ isolines appears to be related to the relative contribution of transpiration to cadmium translocation to the shoot. Increased transpiration was associated with increased cadmium content in the ‘low’ isolines but in the ‘high’ isolines increased cadmium in the shoot occurred independently of the volume of water transpired.     

Neuroendocrine system of the digestive tract in Rhamdia quelen juvenile: an immunohistochemical study

In this work, an immunohistochemical study was performed to determine the distribution and relative frequencies of some neuromodulators of the digestive tract of silver catfish (Rhamdia quelen). The digestive tract of silver catfish was divided into six portions; the oesophagus, stomach, intestine (ascendant, descendant and convoluted segments), and rectum. Immunohistochemical method using a pool of specific antisera against-gastrin, -cholecystokinin-8, -leu-enkephalin, -neuropeptide Y, -calcitonin gene-related peptide (CGRP), and -vasoactive intestinal peptide (VIP) was employed. Immunoreactivity to all antisera was identified in neuroendocrine cells (NECs) localized in the gut epithelium, although no reaction was observed in the oesophagus or stomach. The morphology of NECs immunopositive to each antibody was similar. They were slender in shape, with basally located nucleus, and their main axis perpendicular to the basement membrane. The number of NECs immunoreactive to all antisera was higher in the ascendant and descendant intestine, exhibiting a decreasing trend toward distal segments of the gut. In addition, immunoreactivity to CGRP and VIP was observed in the myenteric plexus and nerve fibers distributed in the mucosal, submucosal and muscular layers. The higher number of immunopositive NECs in the ascendant and descendant intestine may indicate the primary role of these segments in the control of food intake by means of orexigenic and anorexigenic peripheral signals.