SEM Observations on the Marine Nematode Dracognomus simplex (Gerlach, 1954) Allen and Noffsinger, 1978 (Draconematidae: Prochaetosomatinae)

The free-living marine nematode Dracognomus simplex (Gerlach, 1954) Allen &Noffsinger, 1978 was studied by scanning electron microscopy (SEM). The morphology of males and females is described and illustrated in detail. In addition to the typical and modified adhesion tubes, a new type of posterior adhesion tube was discovered. A neotype is proposed for Dracognomus simplex, and D. simplex sensu Decraemer &Gourbault, 1986 is renamed as Dracognomus americanum n. sp. Additionally, a key toward the Dracognomus species is proposed.     

A new marine nematode species of the genus Dinetia (Nematoda: Draconematidae) from South Korea

A new draconematid nematode species of the genus Dinetia Decraemer and Gourbault, 1997 is described from the subtidal sediments and small logs from the eastern coast of South Korea. Dinetia orientalis n. sp. mainly differs from D. nycterobia Decraemer and Gourbault, 1997 by the following characters: large number of cephalic adhesion tubes (38-42 in male and 37-40 in female), number of posterior sublateral adhesion tubes (9-11 in male and 13-14 in female) and posterior subventral adhesion tubes (17-22 in male and 19-24 in female), the buccal cavity (narrow and armed with a dorsal and two weak ventrosublateral teeth), spicules (strongly arcuated and with a pair of strongly dilated gubernaculums around distal part of spicules), and higher "c" value (8.3-10.4 in male and 8.5-10.7 in female). This is the first report on free-living marine nematodes from South Korea, and the first record of the genus Dinetia in the Northwest Pacific.     

Further comment on drag and reconfiguration of macrophytes

1. The paper by Sand‐Jensen (2003 , Freshwater Biology, 48 , 271), and the subsequent comment and reply ( Sukhodolov, 2005 , Freshwater Biology, 50 , 194; Sand‐Jensen, 2005 , Freshwater Biology, 50 , 196), are discussed. I present partial theory describing how the macrophyte bending angle changes with increased flow velocity, demonstrating a nonlinear relation. 2. While Sand‐Jensen (2005) is correct that plant wetted area is the only characteristic area that can be measured easily, some other measure of the exposure area of the plant stand to the flow may be preferable. The relationship in Sand‐Jensen (2003) between the dimensionless drag coefficient and flow velocity depends on the definition of characteristic area. Hence, the analysis involving the drag parameter in Sand‐Jensen (2003) should be interpreted with care.     

The relation between habitus and habitat structure as evidenced by a new species of Glochinema (Nematoda, Epsilonematidae) from the plateau of the Great Meteor Seamount1

Glochinema kentrosaurides sp. n. is described from coarse biogenic sands on the plateau of the Great Meteor Seamount at 455 m depth. It is characterized by two rows of 12 long thorns between the caudal body enlargement and the tail base, by two bands of hair-like spines dorsally on the body enlargement, by a diverse waffle-like ornamentation of the cuticle, by a pair of small dorsal pharyngeal thorns, by five to six rows of ambulatory setae adding up to a total of 28 setae in the male and 24 in the female, and by a sexual dimorphism in the form of the amphids. It is the first record of Glochinematinae from the Atlantic, all others being known from the Pacific so far. The distinguishing features of all species of Glochinema Lorenzen, 1974 are summarized. The new species blurs the distinction between the genera Glochinema and Metaglochinema Gourbault & Decraemer, 1996. It is discussed that some of the salient external features may have less systematic importance than hitherto believed because of their variation in response to habitat structure.     

A new species of Aberrapex Jensen, 2001 (Cestoda: Lecanicephalidea) from Taeniura lymma (Forsskål) (Myliobatiformes: Dasyatidae) from off Sabah, Malaysia

A new lecanicephalidean species of Aberrapex Jensen, 2001 is described from the blue-spotted fantail ray Taeniura lymma (Forsskål) collected off the eastern coast of Sabah in Malaysian Borneo. This is the first record of a lecanicephalidean tapeworm from the island of Borneo and the first record of Aberrapex from this host species. A. manjajiae n. sp. is easily distinguished from its two congeners, A. senticosus Jensen, 2001 and A. arrhynchum (Brooks, Mayes & Thorson, 1981) Jensen, 2001, based on its overall smaller size (928–1,971 vs 1,485–6,333 and up to 3,350μm long, respectively) and fewer testes (10–19 vs 20–40 and 18–25, respectively). In addition, A. manjajiae n. sp. is readily distinguished from A. senticosus based on a more anteriorly positioned genital pore (76–85 vs 52–72% of proglottid length from posterior end) and its distal bothridial microthrix pattern. A. manjajiae n. sp. can be further distinguished from A. arrhynchum based on its smaller scolex (82–101 × 119–164 vs 177–186 × 233–326μm). The host distribution of Aberrapex is expanded from the Myliobatidae to include the Dasyatidae.     

Epsilonematidae (Nematoda) from a cold-water coral environment in the Porcupine Seabight, with a discussion on the status of the genus Metaglochinema Gourbault & Decraemer, 1986

Thirteen species of nematodes from the family Epsilonematidae Steiner, 1927 were found to be associated with a cold-water coral reef in the Porcupine Seabight. Among them, four species were already known from various locations such as Chile and Papua New Guinea. Three new species are described here: Glochinema trispinatumsp. n. is recognized by three dorsal thorns in the pharyngeal region. This species was also recovered from the Antarctic shelf. Epsilonema multispiralumsp. n. is characterised by a multispiral amphid consisting of 3.25 coils. Bathyepsilonema lopheliaesp. n. is characterised by its body length, the position and relative width of the amphids and the nature of the cuticular ornamentation. Within the subfamily Glochinematinae Lorenzen, 1974, the number and arrangement of ambulatory setae is considered not to be of diagnostic importance. The former species Metaglochinema strigosumGourbault & Decraemer, 1993 is therefore classified under the genus GlochinemaLorenzen, 1974. The original genus diagnosis of Metaglochinema, now a monotypic genus, is adjusted. The geographic distribution of epsilonematid nematodes is briefly discussed.     

Residues of Polychlorinated Biphenyls (PCB) and Organochlorine Insecticides in Liver Tissue from Terrestrial Danish Predatory Birds

Several observations of the occurrence of PCB in marine organisms have been published since Jensen (1966) proved the presence of these compounds as pollutants in the environment. In the last years the occurrence in terrestrial animals, especially birds have been reported a.o. by Prestt & Moore (1970).     

A new species of sunbird from Tanzania

During August 1981 a ten-day visit was paid to Mwanihana Forest Reserve, a rain forest on the eastern scarp of Uzungwa Mountains, eastern Tanzania. Stuart et al. (1981) and Stuart & Jensen (1981) have documented a number of notable range extensions of forest birds from this area, which, until recently, was unexplored by ornithologists. Jensen & Stuart (in press) described four new subspecies of birds and Homewood & Rodgers (in press) described a new subspecies of the Crested Mangabey Cercocebus galeritus from the same locality. Both the physiognomy of the rainforest and the composition of the avifauna suggest strong affinities between Mwanihana Forest, and the forested scarps of other basement block mountains in eastern Tanzania, most notably the Mgurus and the Ulugurus (Stuart, et al. 1981).
On 2 August 1981, while carrying out a mist-netting study in the forest at 1000 m, a male specimen was caught of a very distinct and hitherto undescribed sunbird. On a subsequent visit in September 1981, Miss T. A. van der Willigen, S. N. Stuart and Dr K. M. Howell secured a female specimen of this new species to be described as:     

Macrophages as a battleground for toxoplasma pathogenesis

In this issue of Cell Host & Microbe, Jensen et?al. (2011) show that clonal lineages of Toxoplasma gondii have evolved distinct ways of subverting their favored host cell, the macrophage. The results suggest that T.?gondii and the ROP kinases can be used to probe immune signaling pathways.     

Quantitative defense theory and patterns of feeding by oak insects

Summary Patterns of herbivory over a two year period on Quercus emoryi (Fagaceae) were correlated with seasonal and yearly changes in tannin and protein content. Quantitative defense theory predicts that tannin and protein content in apparent plants should be negatively and positively correlated, respectively, with degree of herbivory. Most herbivory occurred early in the growing season, but the pattern varied between the two years. Tannin and protein content sometimes varied negatively and sometimes positively with degree of herbivory; they did not consistently covary with herbivory. Protein content was positively correlated with herbivory in 1981–1982 but not in 1982–1983. Condensed tannin content was negatively correlated with herbivory in 1981–1982 but not in 1982–1983. Hydrolysable tannin content was positively correlated with herbivory activity. Multiple regression analyses indicated these phytochemical variables explained either no significant variation in herbivory (1982–1983) or did so in a fashion opposite (1981–1982) to the predictions of the theory of quantitative defense.Feeding by oak insects was not solely a function of seasonal changes in quantitative defenses and nutrients. Obviously, population dynamics of the insects are sensitive to factors other than phytochemistry of the trees and I discuss other factors that can influence patterns of herbivory.     

Book Reviews

Book reviewed in this article:
Nedwell, D.B. & Brown, CM. (Eds.) (1982) Sediment Microbiotogy.
Thornton, J.A. (Ed.) (1982) Lake Mcllwaine (The Eutrophication and Recovery of a Tropical African Man-Made Lake ).
Edwards, R.W. & Brooker, M.P. (1982) The Ecology of the Wye.
Wilson, R.S. & McGiU, J.D. (1982) A Practical Key to the Genera of Pupal E.xuviac of the British Chironomidae.     

Covariances of relatives and selection response in generations of selfing from an outcrossed base population

Summary The covariances of relatives arising under selfing from a general outbred base population in linkage equilibrium and without epistasis given by Cockerham (1983) are expressed in an alternative form which is an extension of the treatment by Mather and Jinks (1982) of the more restricted population descended from a single F₁ family. Whereas no more than two quadratic components are required to describe any covariance in the case of F₁, descendants, this more general case calls for a total of four, three of which are needed for any particular covariance. The estimation of covariances and their use for the prediction of selection response is described for breeding programs initiated by one or more cycles of intermating among a number of parental lines, as advocated by Hansel (1964) and Jensen (1970). It is pointed out that the homozygous lines descended from such a population will have up to twice as much variance as those from an F₁ between a randomly chosen pair from the same population of parents. The selection method is especially recommended for undeveloped species in which the parental lines are not well characterized and large selection responses are needed.     

Hormonal Control of Elongation of Tobacco Cells Derived from Protoplasts

Spherical protoplasts (30–40 µm in diameter), isolatedfrom cultured tobacco cells, elongated rapidly during a cultureperiod of 3 to 8 days and finally assumed a long cylindricalform (300–400 µm in length). The optimum concentrationof a-naphthaleneacetic acid and benzyladenine for the elongationwas 0.1 mg/liter and 1 mg/liter respectively. (Received August 10, 1982; Accepted November 12, 1982)     

Scientific Report on the Belgian Expedition to The Great Barrier Reef in 1967. Nematodes V Observations on Desmoscolex (Nematoda, Desmoscolecida) with description of three new species

Three new species of Desmoscolex , found in samples from Yonge Reef, Lizard Island, Nymphe Island and between One Tree Isles and Wistari Reef are described: D. australiens sp.n., characterized by the head-shape with naked semi-circular anterior part, by the jointed cephalic setae inserted close to the anterior extremity and by the shape of the gubernaculum with less sclerotized proximal part; D. membranosas sp.n. close to D. granulatus Decraemer, 1974, but differing from it by the presence of a partly disconnected circumoral membrane and by the oval amphids not reaching the extreme anterior end; D. yongei sp.n. resembling D. americanus Chitwood, 1936, but differing from it by the longer and more slender spicules, by the presence of fine spines on the secondary rings, by the head-shape without a truncated anterior end and by the almost circular amphids.     

A neural model of interactions subserving prey-predator discrimination and size preference in anuran amphibia

The model described is an extension of a previous model of the optic tectum (Arbib & Lara, 1982; Lara, Arbib & Cromarty, 1982; Lara & Arbib, 1982) and takes into consideration anatomical, physiological and behavioral studies in anurans, as well as earlier modelling efforts (Ewert & Von Seelen, 1974; Didday, 1976). Computer simulations were conducted to analyze how interactions among retina, optic tectum and pretectum may give frogs and toads the ability to discriminate between prey and predator stimuli. Results from simulations have allowed us to reproduce empirical observations, to suggest new experiments, and to postulate what neural mechanisms might be involved in some phenomena related to prey-catching orienting behavior, with direction invariance of prey-predator recognition being a consequence of tectal architecture, and size preference and response latency depending on the motivational state of the animal.     

Asparagine-Requiring Tumor Cell Lines and Their Non-Requiring Variants: Cytogenetics, Biochemistry and Population Dynamics

Asparagine-requiring Jensen and Walker rat tumor cells and their asparagine-independent variants have been analyzed. The following results were obtained: (1) Both cell lines have very low levels of asparagine synthetase, and non-requiring revertants isolated from these lines have elevated levels of the enzyme. (2) No differences in chromosome number were detected between the parent Jensen line and five Jensen non-requiring revertants isolated from it. (3) Both Jensen and Walker cells undergo asparagineless death when deprived of this amino acid, although the Jensen cells do so at a more rapid rate. (4) Jensen requiring lines are at a selective advantage when grown in competition with non-requiring variants in complete medium, and their growth rate is more rapid when grown separately. The selective coefficients for the variant with respect to the asparagine-requiring parent ASN(-) line were 0.94 for the competition experiments and 0.83 for growth rate estimates. (5) A somatic cell hybrid between Chinese hamster cells (which require asparagine at low densities, and posses measurable synthetase activity) and the Walker line was found to be asparagine-independent, and it possessed enzyme levels equivalent to the hamster parent. The results of these investigations suggest a parallel with microbial auxotrophic mutants and can be understood in terms of alterations within nuclear structural genes.     

Co-accumulation of prephenate, L-arogenate, and spiro-arogenate in a mutant of Neurospora

A mutant strain of Neurospora crassa blocked in each of the initial steps of tryptophan, tyrosine, and phenylalanine biosynthesis was previously shown to accumulate and secrete prephenate and L-arogenate (Jensen, R.A., Zamir, L.O., St. Pierre, M., Patel, N., and Pierson, D.L. (1977) J. Bacteriol. 132, 896-903). We now report the co-accumulation of yet another compound which was identified (Zamir, L.O., Tiberio, R., Jung, E., and Jensen, R.A. (1982) J. Biol. Chem. (1983) 258, 6486-6491) as the lactam derivative of L-arogenate. This structure, spiro-arogenate, undergoes a facile acid-catalyzed conversion to L-phenylalanine (as does L-arogenate). Since L-arogenate is conveniently quantitated as 5-dimethylaminonapthalene-1-sulfonyl (dansyl)-phenylalanine following acidification and dansylation, the unknown presence of spiro-arogenate may easily lead to overestimation of L-arogenate present in mixtures. Reliable quantitative assays for both L-arogenate and spiro-arogenate in mixtures were designed utilizing [3H]dansyl-chloride and exploiting the inability of the spiro-arogenate molecule to be dansylated in contrast to L-arogenate. The initial appearance of spiro-arogenate during accumulation lagged behind prephenate and L-arogenate, and spiro-arogenate accumulation leveled off after 5 days while prephenate and L-arogenate accumulations continued. It seems likely that spiro-arogenate is derived directly from L-arogenate. Prephenate, L-arogenate, and spiro-arogenate comprised about 70, 15, and 15% fractions of the total accumulation in a representative accumulation experiment designed to maximize spiro-arogenate yields. Modest variations in co-metabolite ratios were obtained under nutritional conditions where carbon source, growth temperature, duration of incubation time, and amino acid additions were experimental variables.     

Nematodes from the Strait of Magellan and the Beagle Channel (Chile): Description of four new species of the Comesomatidae

Four nematode species of the Comesomatidae from the Strait of Magellan and the Beagle Channel, Chile, are described as new to science. Comesoma hermani n. sp. can be separated from similar species, Comesoma bermudense Jensen & Gerlach, 1977, Comesoma minimum Chitwood, 1937 and Comesoma chilense Jensen & Gerlach, 1977 by the difference of body length, cephalic setae length, the ratio of the subcephalic setae to cephalic setae length and the ratio of spicule to anal body diameter. Dorylaimopsis magellanense n. sp. is identified by the lateral differentiation of 3–4 longitudinal rows of enlarged dots, the curved spicules are prominently jointed and with a ventral protrusion. Hopperia beaglense n. sp. could be easily recognised by both the rounded tail tip and anterior head end which differs from all the species of this genus except H. dorylaimopsoides (Allgén, 1959), which has, however, a smaller de Man ratio 'a' and reflexed ovaries. Hopperia arntzi n. sp. has a shorter body length which differs from the closest species, Hopperia americana Ward, 1984 and Hopperia muscatensis Warwick, 1973. Furthermore, the de Man ratio 'a' is different between our specimens and the other two species. An identification key to all known species of the genus Hopperia is provided.