The feeding mechanism of Yoldia ( ═ Aequiyoldia ) eightsi (Courthouy)

1988 ◽  
Vol 232 (1269) ◽  
pp. 431-442 ◽  
Keyword(s):  
Posterior Part ◽  
Dry Mass ◽  
Mantle Cavity ◽  
Bivalve Mollusc ◽  
Suspension Feeder ◽  
Surface Layers ◽  
Processed Material ◽  
Ciliary Action ◽  
Inhalant Siphon ◽  
Mass Basis

The protobranch bivalve mollusc Yoldia eightsi Courthouy is both a deposit feeder (on mud) and a suspension feeder (on diatoms in the ventilatory streams, which are trapped on the ctenidia). The species has a similar anatomy to other Yoldia species, but is a more shallow burrower which adopts a more horizontal shell orientation than the vertically burrowing Yoldia limatula and Yoldia ensifera . Although capable of feeding on the surface layers of mud by extending its palp proboscides outside the partly buried shell, Yoldia eightsi spends most of its time feeding while totally buried. To do this, sediment is taken into the mantle cavity by opening the shell valves, or by foot movements. The sediment is moved by ciliary action to the posterior part of the mantle cavity where it forms a compact, mucus-coated sediment slug. The slug is repeatedly sorted largely by the palp proboscides, fine material being transferred to the mouth via the palps. Sorting appears to be done on a simple size–density basis, with large, dense particles being rejected. After sorting, the inorganic fraction of the slug is expelled through the inhalant siphon (‘pseudofaecal plume’). Expulsions occur every 6–35 min. True faeces (‘faecal plume’) are expelled much more frequently in the expiratory bursts of water from the exhalant siphon. Pseudofaecal output is about 170 times the faecal output (on a dry mass basis), suggesting that Yoldia eightsi ingests 0.6% of processed material.

scholarly journals Notes on the Ciliate Boveria stevensi Issel from Galeomma turtoni Sowerby at Plymouth

1931 ◽  
Vol 17 (2) ◽  
pp. 577-582 ◽  
Author(s):  
D. L. Mackinnon ◽  
H. N. Ray
Keyword(s):  
Mantle Cavity ◽  
Bivalve Mollusc ◽  
Marine Biological Laboratory ◽  
Marine Biological ◽  
Biological Laboratory

The little bivalve mollusc Galeomma turtoni is not very common of the coast of South Devon; but two specimens were brought in while we were working at the Marine Biological Laboratory last August, and when we examined them we found that the branchiæ and mantle cavity were aswarm with a small colourless ciliate.

scholarly journals Differences in Leaf Cuticle Structure and Efficacy among Eastern Redbud and Mexican Redbud Phenotypes

1995 ◽  
Vol 120 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Jimmy L. Tipton ◽  
Marcia White
Keyword(s):  
Leaf Area ◽  
Water Loss ◽  
Loss Rate ◽  
Dry Mass ◽  
Abaxial Surface ◽  
Cercis Canadensis ◽  
Area Basis ◽  
Detached Leaves ◽  
Eastern Redbud ◽  
Mass Basis

The objective of this study was to compare the structure and efficacy in terms of retarding cuticular transpiration of leaf cuticles from eastern redbud (Cercis canadensis L.) and dull-leaf and glossy-leaf Mexican redbud [Cercis canadensis var. mexicana (Rose) M. Hopk.]. Leaves of Mexican redbud exhibited several xeromorphic characteristics compared to eastern redbud: a smaller, thicker leaf with thicker cuticles, more cuticular wax, a higher specific leaf mass, and greater hydrated water content on a leaf area basis. Mexican redbuds with a glossy leaf differed from those with a dull leaf only in a thicker adaxial cuticle lacking wax crystallite on the surface. Epicuticular wax crystallite were present on the abaxial surface of all leaves examined. Detached leaves of eastern redbud had a higher water loss rate than those of Mexican redbud only on a dry mass basis, not on a leaf area basis. There was no difference in the rate of water loss by detached leaves of glossy-leaf and dull-leaf Mexican redbuds after 4 hours.

scholarly journals White Hop Shoot Production in Slovenia

2019 ◽  
Vol 57 (4) ◽  
pp. 525-534 ◽  
Author(s):  
Mateja Vidmar ◽  
Veronika Abram ◽  
Barbara Čeh ◽  
Lea Demšar ◽  
Nataša Poklar-Ulrih
Keyword(s):  
Chlorogenic Acid ◽  
Human Health ◽  
Pesticide Residues ◽  
Total Phenolics ◽  
Limit Of Detection ◽  
Radical Scavenging ◽  
Dry Mass ◽  
Shoot Production ◽  
Reducing Activity ◽  
Mass Basis

Harvesting of white hop shoots might be justified if they can be shown to be beneficial to human health. The aim of the present study is to determine the effects of hop cultivars and year of production on total phenolics, antioxidant potential, microelements and pesticide residues. Biomass per plant was highly variable among the cultivars (3.1-7.1 g dry mass per plant) and depended on hop cultivar and year (2009-2011). Total phenolics as chlorogenic acid equivalents (CAE) on dry mass basis varied from 0.60 to 1.80 mg/g, and showed significant effects across hop cultivar and year. The radical scavenging activities of the samples collected in years 2010-2012 ranged from 11 to 19 μg CAE. Ferric reducing activity was <0.01, with significantly different effects across hop cultivars (pC≤0.05) and year (py≤0.05) observed only in 2012. Traces of microelements and potentially active compounds from the use of pesticides in white hop shoots of Humulus lupulus ‘Dana’ were analysed. The content of zinc in the hop shoots on dry mass basis was very low (4 mg/kg), and it was below the limit of detection in the soil. The content of copper in the hop shoots was also very low (2.3 mg/kg), while in the soil it was below the critical emission (100 vs 300 mg/kg, respectively). All 182 active ingredients from the residues of the previously used pesticides were below the limits of detection. It can be concluded that these white hop shoots are better antioxidants than hop cones and hop leaves, and that they do not contain any pesticide residues.

A new genus Turneroconcha (Bivalvia: Vesicomyidae: Pliocardiinae) for the giant hydrothermal vent clam ‘Calyptogena’ magnifica

Zootaxa ◽  
2020 ◽  
Vol 4808 (1) ◽  
pp. 79-100 ◽  
Author(s):  
ELENA M. KRYLOVA ◽  
HEIKO SAHLING
Keyword(s):  
Morphological Analysis ◽  
New Genus ◽  
Posterior Part ◽  
Morphological Characters ◽  
Morphological Data ◽  
Monotypic Genus ◽  
East Pacific ◽  
Inhalant Siphon ◽  
The Right ◽  
Galapagos Rift

A new monotypic genus, Turneroconcha, is established for T. magnifica (Boss & Turner) which was originally assigned to the genus Calyptogena Dall. The distinguishing morphological characters of the new genus are the combination of both conchological and anatomical features including: the presence of only two tooth elements in the right valve; submerged location of the posterior part of the posterior lamellar ligament layer; the absence of a subumbonal pit, lunular incision, escutcheon and pallial sinus; the presence of both pairs of demibranchs; the tubular structure of marginal parts of the interlamellar septa in gills; an inner valve of the inhalant siphon without processes; tentaculate inner mantle fold 3 and a Z-shaped digestive tract. Analysis of morphological data on Recent and fossil pliocardiines shows that Turneroconcha gen. nov. can be presently considered as a monotypic genus. The comparative morphological analysis of the new genus with described pliocardiine genera is consistent with available molecular results. Turneroconcha gen. nov. is endemic to the East-Pacific Rise and Galapagos Rift and occurs at water depths of 2251 to 2791 m. It is the only pliocardiine genus known so far with a mainly epifaunal life habit. No fossils of Turneroconcha gen. nov. are known.  

The mechanism of boring in Zirphaea crispata (L.) (Bivalvia: Pholadidae)

1968 ◽  
Vol 170 (1019) ◽  
pp. 155-173 ◽  
Keyword(s):  
Adductor Muscle ◽  
Mantle Cavity ◽  
Clockwise Rotation ◽  
Mantle Tissue ◽  
Counter Pressure ◽  
Time Period ◽  
Adductor Muscles ◽  
Inhalant Siphon ◽  
Main Activity ◽  
Low Pressures

The main activity during boring by Zirphaea crispata consists of the cyclical repetition of a group of movements, termed the boring cycle. Each boring cycle comprises the retraction of the shell to the base of the burrow, and the abrasion of the walls of the burrow by movements of the shell caused by the consecutive action of the posterior and anterior adductor muscles, supplemented by an accessory ventral adductor muscle. Each boring cycle is followed by slight anticlockwise and clockwise rotation of the animal in the burrow, while simultaneously the siphons are withdrawn and re-extended. A second type of rotational movement, resulting from changes in the position of the foot in the burrow, occurs over a longer time period, so that a circular, drop-shaped burrow is formed. The material abraded from the base of the burrow is collected into the mantle cavity and ejected as pseudofaeces from the inhalant siphon at intervals during boring. The pressures developed in the mantle cavity and haemocoele during boring are small compared with those generated by burrowing forms. During the boring cycle, low pressures (2 to 3 cm) serve to press the foot against the wall of the burrow where adhesion is aided by mucous secretion and by the action of a counter pressure from a pad of mantle tissue dorsally. Fluid is retained in the foot, and in the expanded mantle margins within the spaces of a loosely arranged connective tissue which fills these organs. The fluid filled mantle cavity and haemocoele allow the siphonal retractor muscles to act partly in antagonizing the adductor muscles, so that withdrawal of the siphons during boring restores the gape of the shell. Higher pressures (8 cm) are developed in the mantle cavity and haemocoele during the contraction of the adductor muscles and circular muscles of the siphons which is involved in the expulsion of pseudo-faeces. The tensions exerted by the pedal muscles during boring are small (2 to 2·5 g).

XVII.—Embryogenesis and Larval Organs of the Giant Land Snail Achatina fulica Bowdich

1962 ◽  
Vol 68 (3) ◽  
pp. 237-260
Author(s):  
Krishna Chandra Ghose
Keyword(s):  
Digestive Gland ◽  
Posterior Part ◽  
Land Snail ◽  
Mantle Cavity ◽  
Early Embryo ◽  
The Body ◽  
Hind Gut ◽  
Contraction And Relaxation ◽  
Short Time ◽  
Digestive Glands

SynopsisOrganogenesis is completed by 15 days. A modified veliger stage is present. Torsion begins at about the sixth day. The foot rudiment is first to appear. The stomodæum appears as a new structure. The salivary glands develop from the stomodæum by evaginations. The œsophagus is stomodæal, while the crop and the primitive stomach are archenteric in origin. The digestive gland develops as two outgrowths of the primitive stomach. The hind gut is formed by the cells proliferated from the closed posterior end of the archenteron. It opens into the primitive stomach in a 2·5 mm. embryo, and the anus appears very late. The proctodæum is absent. The primordium of the pericardium with the heart, definitive kidney and gonad is mesodermal. The ureter is ectodermal and arises from the mantle cavity by evagination and subsequently communicates with the kidney. Lung and mantle are ectodermal and arise by separate invaginations. The lung fuses with the mantle and loses its separate existence from about a 4 mm. embryo. The nervous system is early to appear and the sense organs, except the statocysts are late in origin. They are ectodermal. The larval organs are: velum, podocyst, larval kidney, nuchal cells and larval digestive gland. The prototroch is the rudiment of the velum. It appears in a very early embryo from the posteroventral part and marks off the anterior border of the stomodæum. The cells of the prototroch become hyaline, vacuolate and develop cilia in a 2·25 mm. embryo, and it is transformed into velum. The velum helps in driving albumen into the larval and adult digestive glands and is resorbed in the body-wall epithelium. The rudiment of the foot first appears after the completion of gastrulation, and the podocyst is differentiated from it later. It steadily increases in size, assumes a hood-like shape, exhibits contraction and relaxation movements and begins to reduce when the embryo attains 3·25 mm. size. It is completely resorbed in the foot. The larval kidneys are mesodermal in origin, appear, in a 920 μ embryo. They begin to degenerate after the formation of the functional definitive kidney and disappear in a late larva. The kidneys are U-shaped, the cells of the closed anterior and bear pseudopodia, which are almost totally replaced by cilia afterwards. The kidney opens to the exterior posteriorly. The cells become vacuolated and excretory granules accumulate in the vacuoles. The nuchal cells first appear in a 2·5 mm. embryo and are excretory. They increase both in number and size with the growth of the embryo and persist throughout the larval period. The endoderm cells of the major portion of the archenteron except a small posterior part, enlarge in size, develop vacuoles and form a larval digestive organ for the purpose of digestion of albumen. Even after the formation of the adult digestive gland, the larval digestive gland functions for a short time, then degenerates and disappears at the end of the larval life.

scholarly journals Isolation, Screening and Optimization of Estuary Region (Khambhat, Gujarat) Microalgae for Lipid/Oil Production

2015 ◽  
Vol 3 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Mahendraperumal Guruvaiah ◽  
Madhuri Narra ◽  
Garima Dixit ◽  
Punit Karawadia ◽  
Deval Shah
Keyword(s):  
Nitrogen Concentration ◽  
Dry Mass ◽  
Total Hardness ◽  
Acetyl Coa Carboxylase ◽  
Standard Laboratory ◽  
Solvent Extraction Method ◽  
Cyanobacterial Species ◽  
Water And Soil Samples ◽  
Unialgal Culture ◽  
Mass Basis

Water and soil samples were collected from gulf of Khambhat region, Gujarat. The cations and anions like calcium, chloride, fluoride, magnesium, sulphate and total hardness as calcium carbonate were analyzed. Collected estuarine samples were cultured in three different media under standard laboratory conditions. These enrichments were then used to isolate pure unialgal culture by conventional method. Thirty four isolates belonging to twelve species of Cyanobacteria, twenty species of Chlorophyta and two taxa of Bacillariophyta were identified and are maintained at SPRERI centre. The Chlorophyta were found better accumulators of lipids than the cyanobacterial species. Five promising strains (SBC 7, SBC 9, SBC 17, SBC 18 and SBC 19) have been selected. In-house isolates SBC19 and SBC 17 showed highest acetyl CoA carboxylase (ACCase) of 55.2 (U/ml) and 51.2 (U/ml) respectively, with 0.375 g l-1 nitrogen concentration in 24 days. Biomass production was highest for 2.4 g/l, (SBC 19) and 2.7 g/l (SBC 17) with 1.5 g l-1 nitrogen concentration. The highest lipid content was 52% and 48% in SBC19 and SBC 17, respectively, with 0.375 g l-1 nitrogen concentration of solvent extraction method. Lipid accumulation was found enhanced by more than 50% on dry mass basis under nitrogen starvation.Int J Appl Sci Biotechnol, Vol 3(2): 197-201 DOI: http://dx.doi.org/10.3126/ijasbt.v3i2.12534 

scholarly journals 5-kD Zinc-binding Protein Accumulation in Macrophylla-decline-affected Citrus

1998 ◽  
Vol 123 (3) ◽  
pp. 357-360
Author(s):  
K.C. Taylor ◽  
H.L. Geitzenauer
Keyword(s):  
Binding Protein ◽  
Leaf Tissue ◽  
Dry Mass ◽  
Tree Canopy ◽  
Protein Accumulation ◽  
Nutrient Deficiencies ◽  
Phloem Tissue ◽  
The Status ◽  
Citrus Orchards ◽  
Mass Basis

Macrophylla-decline (MD)-affected citrus display apparent nutrient deficiencies in a sectorial pattern within the citrus tree canopy. The status of several elements (Ca, Cu, Fe, Mg, Mn, and Zn) was assessed in MD and healthy citrus selected from the same citrus orchards. Leaf and phloem tissues were sampled from mature, reproductive trees. Levels of Ca, Cu, Fe, Mg, and Mn were unaffected by the disorder in leaf or phloem tissues. Zinc was diminished in the leaves of MD citrus, and elevated in the whole phloem tissue (2.57-fold on a dry mass basis). Calcium and Cu were sufficient, while Mg, Fe, and Mn were slightly diminished in the leaf tissue, but phloem levels of these elements were not significantly different from that present in the phloem of healthy trees. Since Zn appeared to be redistributed to the phloem tissue from the leaves, the accumulation of the phloem specific, 5-kD Zn-binding protein (ZBP) was assessed in Macrophylla decline trees relative to healthy trees. The 5-kD ZBP was 4.77-fold greater in the phloem of MD citrus relative to healthy. This appears to account for the 2.4-fold greater level of Zn (on a fresh mass basis) found in the crude phloem extracts of the decline-affected citrus relative to healthy. In the purified ZBP fraction from decline-affected citrus, there was 4.73-fold greater Zn than in the ZBP purified from healthy. However, the ratios of Zn to ZBP were equivalent between MD citrus and healthy citrus, suggesting that phloem Zn accumulation in MD citrus is associated with the 5-kD ZBP.

Observations on the morphology and behaviour of Chilina fluctuosa Gray (Chilinidae), with a discussion on the early evolution of pulmonate gastropods

1983 ◽  
Vol 300 (1101) ◽  
pp. 463-491 ◽  
Keyword(s):  
Vascular System ◽  
Mantle Cavity ◽  
Particulate Material ◽  
Early Evolution ◽  
Suboesophageal Ganglion ◽  
Surface Layers ◽  
Representative Species ◽  
Freshwater Habitats ◽  
The Rich ◽  
Feeding Systems

An account is provided of (i) the general morphology, (ii) the vascular, nervous and feeding systems, and (iii) aspects of the behaviour of a representative species of the pulmonate genus Chilina . Examination of this genus has aided in understanding the pattern of early evolution of freshwater pulmonates from their marine prosobranch ancestors and of their divergence from opisthobranchs. The gross morphology of Chilina is adapted to ploughing through the surface layers of soft substrata. Although C. fluctuosa was found on rocks, it was nevertheless capable of burrowing into sand, using a stereotyped digging cycle. Streamlining to facilitate burrowing was achieved by nuchal shortening and by a ‘detorsion’ of the mantle complex as in opisthobranchs. The nuchal shortening incurred loss of a major vascular pathway which, in monotocardian prosobranchs, drains the head-foot. ‘Detorsion’, however, provided a substitute which incorporates the anterior roof of the mantle cavity where, in Chilina , the precursor of the rich pulmonary plexus characteristic of later pulmonates may be discerned. The suprapallalial vascular system is described in detail. In contrast, it is apparent that increased reliance on burrowing in opisthobranchs brought about loss of the anterior region of the mantle cavity, and thus any potential for development of a plexus in that region. Enclosure of the mantle cavity, which clearly pre-adapted the mantle complex to function also as a ‘lung’, was necessary to reduce clogging of the mantle cavity by particulate material. Only water is held in the cavity of Chilina flutuosa , whose habitat is rivers, but both air and water may be held in the mantle complex of other species found in Chile. The nervous system is extremely similar to that of the primitive opisthrobranch Acteon , but the posterior section of the visceral loop is shorter owing to greater nuchal reduction. The loop is uncrossed, though the supraoesophageal ganglion lies only a little right of the suboesophageal ganglion. The musculature of the buccal mass is extremely similar to that of Lymnaea and Planorbarius , and is designed for moving and tensing a broad radular ribbon. It is argued that the buccal morphology characteristic of these snails evolved to manipulate quantities of particulate material during the early infaunal phase, and only later was used to great effect in both microphagous and macrophagous feeding. Collectively, the observations made on C. flluctuosa (and also on estuarine species found in Chile) support the contention that the Basommatophora invaded freshwater habitats via estuarine niches. Continuity during this progression was apparently provided by soft substrata, and probably by diatoms as a food source. Previous arguments purporting a terrestrial or semi-terrestrial origin for the limnic basommatophorans are refuted.

scholarly journals Structural and functional leaf traits of two Gochnatia species from distinct growth forms in a sclerophyll forest site in Southeastern Brazil

2012 ◽  
Vol 26 (4) ◽  
pp. 849-856 ◽  
Author(s):  
Davi Rodrigo Rossatto ◽  
Rosana Marta Kolb
Keyword(s):  
Leaf Traits ◽  
Dry Mass ◽  
Co2 Assimilation ◽  
Southeastern Brazil ◽  
Forest Site ◽  
Growth Forms ◽  
Ecophysiological Traits ◽  
Leaf Dry Mass ◽  
Environmental Variations ◽  
Mass Basis

Gochnatia is very common in different phytophysiognomies in the Cerrado of São Paulo State, occupying open and closed areas. In this study, we compared the leaf anatomy and some ecophysiological traits of two species of Gochnatia, one a shrub (Gochnatia barrosii Cabrera) and the other a tree (Gochnatia polymorpha (Less.) Cabrera), which both occur in an area of "cerradão" at the Estação Ecológica de Assis, SP. We found qualitative structural differences between the species, with G. barrosii presenting amphistomatic leaves with a uniseriate epidermis and G. polymorpha showing hypostomatic leaves and a multiple epidermis or hypodermis on the adaxial surface. Moreover, the G. barrosii leaves had lower values in tissue thickness (with the exception of the epidermis on the abaxial surface) and leaf thickness in relation to G. polymorpha. There were differences in CO2 assimilation both in area and leaf dry mass basis, and differences in specific leaf area, which was higher in G. barrosii. Although the G. barrosii leaves were much less sclerophyllous than the G. polymorpha leaves, we found no differences in the efficiency of water use. The results suggest that plants from the same genus, but with distinct growth forms, differ in their leaf traits to deal with the environmental variations that they grow in.

Sign in / Sign up

Export Citation Format

Share Document