Description of two new species of Prodontorhabditis Timm, 1961 (Nematoda: Rhabditidae) from India.

Two new species, Prodontorhabditis robustus sp. n. and P. grandistoma sp. n. are described and illustrated from rotting banana rhizome and decaying organic matter respectively. P. robustus sp. n. is characterized by thin and slender females with L= 490-625 µm; a= 25.8-34.7; b= 4.9-6.4; c= 2.4-3.7, an arched cheilostom with curved walls bearing basal dorsal and subventral denticles at the same level, males with 20-23 µm long, robust spicules with prominent dorsal velum and lateral spurs at its bifurcated distal tip and gubernaculum with attenuated proximal end. P. grandistoma sp. n. is characterized by plump females with L= 440-552 µm; a= 23.9-25.5; b= 4.4-5.7; c= 2.9-4.2, a long, narrow stoma of length 6-7 times diameter; the cheilostom straight but, wider anteriorly with a basal dorsal denticle and anterior subventral denticles, rectum with dilated lumen, males with 17-20 µm long, relatively slender spicules and a terminally indented bursa. This is the first report of Prodontorhabditis species from India. An updated list of species, a key to their identification and a compendium of their morphometrics and diagnostic features is presented.

Description of a new and two known species of Cephaloboides Rahm, 1928 (Nematoda: Rhabditidae) from India, with discussion on the taxonomy of the genus.

A new species of Rhabditidae, collected from manure, is described and illustrated. Cephaloboides anisospiculus sp. n., an amphimictic species with a 1:1 sex ratio, is characterized by a small to medium-sized body (female: L = 0.5-0.7 mm, a = 13.6-20.0, b = 2.7-3.6, c = 15.4-22.7, c' = 1.0-1.8, V = 51.2-60.9), finely striated, punctated cuticle; slightly raised labial papillae; stoma with slightly anisomorphic metastegostom; presence of epiptygma; eggs measuring 37-42 x 20-24 µm; slightly protruded vulval lips with cuticular flaps; rectum 16-19 µm long; males with small, stout, slightly arcuate spicules with hood-like capitula and genital papillae in 1/2/(1+3)+2+P configuration; bursa leptoderan, greatly reduced and not enveloping the caudal spike. C. curvicaudatus (Schneider, 1866) Zullini, 1982 is also redescribed, with an emended diagnosis. The present population of C. curvicaudatus shows a few minor differences viz., relatively smaller 'b' value, presence of elongate capitula of spicules and strong copulatory muscle bands. Another species, C. parapapillosus (Schuurmans Stekhoven, 1951) comb. n. has been reinstated.

Description of a new species of Acrostichus Rahm 1928 (Nematoda: Diplogastridae) from India with a note on its position and relationship with the congeners.

BACKGROUND: The clade Diplogastridae Micoletzky 1922 largely represents the bacterivorous or predatory nematodes that very often demonstrate phoretic, necromenic or parasitic associations with insects (Sudhaus and Fürst von Lieven 2003). That is the reason, much of the diversity of the family remains undocumented because of their absence from routine soil samples. Due to their variable habitats and niches, these nematodes show ample variation in their stomal armature, feeding behavior and life cycle patterns. NEW INFORMATION: The paper describes and illustrates a new diplogastrid species of genus Acrostichus Rahm 1928 that appears to be the link between the genera Diplogastrellus Paramonov et al. 1952a and Acrostichus. Acrostichus medius n. sp. is characterised by hermaphroditic females and males having faintly striated longitudinal ridges, demarcated lateral fields, amalgamated lips, six adradial cheilostomal plates, moderately-built dorsal tooth, relatively smaller posterior genital branch; large oval uterine pouch and males with robust, heavily cuticularised spicules, each with hood-like capitulum, deeply forked distal end with fine extensions and a ventral attenuated arm; gubernaculum 2/3 of spicule length and rudiments of bursa confined to posterior four pairs of genital papillae. The biogeographical distribution of Acrostichus has been mapped and the relationship between congeners has been analysed cladistically and discussed.

Description of a New and Two Known Species of the Free-living Nematode Paroigolaimella Paramonov, 1952 (Diplogastridae) from India.

This paper describes a new and two known species of Paroigolaimella collected from India. Paroigolaimella helalii n. sp. is characterized by having conspicuous sexual dimorphism in the stoma and pharynx, ovaries with a sphincter separating the mature oocyte from developing ones, a vagina leading to a strong ovijector, a pore-like vulva with cuticular flap; males with slender strongly arcuate spicules with dilated capitula; the gubernaculum slender with expanded plate-like distal end and nine pairs of genital papillae, and four to five pairs of copulatory muscle bands. P. coprophila (Sudhaus and Rehfeld, 1990) Sudhaus and Fürst von Lieven, 2003 collected from leaf litter from a farmyard has been redescribed with reassessment of its distinguishing characters from P. bernensis. P. bodamica (Micoletzky, 1922) n. comb. has been described and its status has been discussed with context to P. bernensis.

The vesicle protein SAM-4 regulates the processivity of synaptic vesicle transport.

Axonal transport of synaptic vesicles (SVs) is a KIF1A/UNC-104 mediated process critical for synapse development and maintenance yet little is known of how SV transport is regulated. Using C. elegans as an in vivo model, we identified SAM-4 as a novel conserved vesicular component regulating SV transport. Processivity, but not velocity, of SV transport was reduced in sam-4 mutants. sam-4 displayed strong genetic interactions with mutations in the cargo binding but not the motor domain of unc-104. Gain-of-function mutations in the unc-104 motor domain, identified in this study, suppress the sam-4 defects by increasing processivity of the SV transport. Genetic analyses suggest that SAM-4, SYD-2/liprin-α and the KIF1A/UNC-104 motor function in the same pathway to regulate SV transport. Our data support a model in which the SV protein SAM-4 regulates the processivity of SV transport.

Axonal transport velocity estimation from kymographs based on curvilinear feature extraction and spline fitting.

Axonal transport velocities are obtained from spatio-temporal maps called kymographs developed from time-lapse confocal microscopy movies of neurons. The kymographs of axonal transport of C.elegans worms are much noisier due to in vivo nature of imaging. Existing methodologies for velocity measurement include laborious manual delineation of axonal movement ridges on the kymographs and thereby determining particle velocities from the slopes of ridges marked. Manual kymograph analysis is not only time consuming but also prone to human errors in marking the ridges. An automated algorithm to extract all the ridges and determine the velocities without significant manual efforts is highly preferred. Not many methods are currently available for such biological studies. We present an almost automated method based on information fusion using LDA classifier, morphological image processing and spline fitting for determining axonal transport velocities. Experimental analysis of 50 kymographs shows considerable reduction of 89% in time taken with manual intervention of 10.83%. Comparitive study with the results of two of the previous literatures shows that our algorithm performs better.

Descriptions of ten known species of the superfamily Mononchoidea (Mononchida: Nematoda) from North India with a detailed account on their variations.

Ten species of the superfamily Mononchoidea from fourteen populations collected during a survey of terrestrial and freshwater habitats of North India, are described and illustrated. The species include Clarkus papillatus (Bastian, 1865) Jairajpuri, 1970, Prionchulus muscorum (Dujardin, 1845) Wu & Hoeppli, 1929, Mylonchulus contractus Jairajpuri, 1970, M. hawaiiensis (Cassidy, 1931) Andrassy, 1958, M. lacustris (Cobb in Cobb, 1915) Andrdssy, 1958, M. minor (Cobb, 1893) Andrassy, 1958, M. obtusicaudatus (Daday, 1899) AndrAssy, 1958, M. vasis Yeates, 1992, Sporonchulus ibitiensis (Carvalho, 1951) Andrassy, 1958 and S. vagabundus Jairajpuri, 1971. Mylonchulus vasis Yeates, 1992 is reported for the first time from India. The variable, as well as the relatively consistent characters are discussed in different populations to assess their role in the diagnosis of species.

Simple microfluidic devices for in vivo imaging of C. elegans, Drosophila and zebrafish.

Micro fabricated fluidic devices provide an accessible micro-environment for in vivo studies on small organisms. Simple fabrication processes are available for microfluidic devices using soft lithography techniques. Microfluidic devices have been used for sub-cellular imaging, in vivo laser microsurgery and cellular imaging. In vivo imaging requires immobilization of organisms. This has been achieved using suction, tapered channels, deformable membranes, suction with additional cooling anesthetic gas, temperature sensitive gels, cyanoacrylate glue and anesthetics such as levamisole. Commonly used anesthetics influence synaptic transmission and are known to have detrimental effects on sub-cellular neuronal transport. In this study we demonstrate a membrane based poly-dimethyl-siloxane (PDMS) device that allows anesthetic free immobilization of intact genetic model organisms such as Caenorhabditis elegans (C. elegans), Drosophila larvae and zebrafish larvae. These model organisms are suitable for in vivo studies in microfluidic devices because of their small diameters and optically transparent or translucent bodies. Body diameters range from -10 µm to -800 µm for early larval stages of C. elegans and zebrafish larvae and require microfluidic devices of different sizes to achieve complete immobilization for high resolution time-lapse imaging. These organisms are immobilized using pressure applied by compressed nitrogen gas through a liquid column and imaged using an inverted microscope. Animals released from the trap return to normal locomotion within 10 min. We demonstrate four applications of time-lapse imaging in C. elegans namely, imaging mitochondrial transport in neurons, pre-synaptic vesicle transport in a transport-defective mutant, glutamate receptor transport and Q neuroblast cell division. Data obtained from such movies show that microfluidic immobilization is a useful and accurate means of acquiring in vivo data of cellular and sub-cellular events when compared to anesthetized animals (Figure 1J and 3C-F). Device dimensions were altered to allow time-lapse imaging of different stages of C. elegans, first instar Drosophila larvae and zebrafish larvae. Transport of vesicles marked with synaptotagmin tagged with GFP (syt.eGFP) in sensory neurons shows directed motion of synaptic vesicle markers expressed in cholinergic sensory neurons in intact first instar Drosophila larvae. A similar device has been used to carry out time-lapse imaging of heartbeat in -30 hr post fertilization (hpf) zebrafish larvae. These data show that the simple devices we have developed can be applied to a variety of model systems to study several cell biological and developmental phenomena in vivo.

The kinesin-3 family motor KLP-4 regulates anterograde trafficking of GLR-1 glutamate receptors in the ventral nerve cord of Caenorhabditis elegans.

The transport of glutamate receptors from the cell body to synapses is essential during neuronal development and may contribute to the regulation of synaptic strength in the mature nervous system. We previously showed that cyclin-dependent kinase-5 (CDK-5) positively regulates the abundance of GLR-1 glutamate receptors at synapses in the ventral nerve cord (VNC) of Caenorhabditis elegans. Here we identify a kinesin-3 family motor klp-4/KIF13 in a cdk-5 suppressor screen for genes that regulate GLR-1 trafficking. klp-4 mutants have decreased abundance of GLR-1 in the VNC. Genetic analysis of klp-4 and the clathrin adaptin unc-11/AP180 suggests that klp-4 functions before endocytosis in the ventral cord. Time-lapse microscopy indicates that klp-4 mutants exhibit decreased anterograde flux of GLR-1. Genetic analysis of cdk-5 and klp-4 suggests that they function in the same pathway to regulate GLR-1 in the VNC. Interestingly, GLR-1 accumulates in cell bodies of cdk-5 but not klp-4 mutants. However, GLR-1 does accumulate in klp-4-mutant cell bodies if receptor degradation in the multivesicular body/lysosome pathway is blocked. This study identifies kinesin KLP-4 as a novel regulator of anterograde glutamate receptor trafficking and reveals a cellular control mechanism by which receptor cargo is targeted for degradation in the absence of its motor.

Imaging in vivo neuronal transport in genetic model organisms using microfluidic devices.

Microfluidic devices have been developed for imaging behavior and various cellular processes in Caenorhabditis elegans, but not subcellular processes requiring high spatial resolution. In neurons, essential processes such as axonal, dendritic, intraflagellar and other long-distance transport can be studied by acquiring fast time-lapse images of green fluorescent protein (GFP)-tagged moving cargo. We have achieved two important goals in such in vivo studies namely, imaging several transport processes in unanesthetized intact animals and imaging very early developmental stages. We describe a microfluidic device for immobilizing C. elegans and Drosophila larvae that allows imaging without anesthetics or dissection. We observed that for certain neuronal cargoes in C. elegans, anesthetics have significant and sometimes unexpected effects on the flux. Further, imaging the transport of certain cargo in early developmental stages was possible only in the microfluidic device. Using our device we observed an increase in anterograde synaptic vesicle transport during development corresponding with synaptic growth. We also imaged Q neuroblast divisions and mitochondrial transport during early developmental stages of C. elegans and Drosophila, respectively. Our simple microfluidic device offers a useful means to image high-resolution subcellular processes in C. elegans and Drosophila and can be readily adapted to other transparent or translucent organisms.

Three New Species of Brevitobrilus (Nematoda) with a Discussion on Relationships within the Genus.

Three new species of the genus BrevitobriusTsalolikhin, 1981 are described. Brevitobrilus glandulatus n. sp. is characterized by conspicuous sphincter between pars dilatata and uterus; two pairs of vaginal glands; spicules having elliptical capitula with small proximal stiffening piece; proximally-arcuate gubernaculum; S3 and S4 smaller than other supplements; S6 out of spicular range and 57-60 micropapillae. Brevitobrilus dimorphicus n. sp. is diagnosed by sexual dimorphism in labial sensilla and amphids; thick-walled rectum with a diverticulum protruding into intestinal lumen and males with boat-shaped spicules and S6 occasionally slightly smaller than other supplements. Brevitobrilus allahabadensis n. sp. possesses large amphids of 28-33% of corresponding labial diameter in both sexes; vagina and uterus with muscular, plicate walls; well developed sphincter between vas deferens and ejaculatory duct; capitulate spicules with sloping ventral and angular dorsal walls; S3, S4 and S6 smaller than other supplements, S6 close to cloaca and 28-37 micropapillae. The relationships of the species of genus Brevitobrilus have been assessed using morphological characters subjected to parsimony and a non cladistic key to identification of species is given.