Neosteinernema longicurvicauda n. gen., n. sp. (Rhabditida: Steinernematidae), a Parasite of the Termite Reticuldermes flavipes (Koller)

A nematode isolated from the termite Reticulitermes flavipes (Koller) was identified and described as a new genus and species, Neosteinernema longicurvicauda. Primary distinguishing characters, by contrast to members of the genus Steinernema, were females having prominent phasmids, a curved tail longer than the body width at the anus, a spiral shape in juvenile-bearing females, and juveniles becoming infective-stage juveniles before emerging from the female; males having prominent phasmids, a digitate tail tip, a characteristic shape of the spicules (foot-shaped with a hump on the dorsal side), and 13-14 pairs of genital papillae, with eight pairs preanal; and infective juveniles having prominent phasmids and a filiform curved tail as long as the esophagus. Adult nematodes are found outside the termite cadaver. Diagnosis of the family Steinernematidae was emended to accommodate the new species.     

Descriptions of Two New Species of Chronogaster Cobb, 1913 from India

Two new species of Chronogaster in India were described and illustrated, based on light and scanning electron microscopy. Chronogaster neotypica n. sp. collected from a sewage slurry was characterized by a medium-sized body, a ventral tail mucro without additional spines, absence of longitudinal incisures in lateral fields, and by the presence of crystalloids in the body. Diagnostic for C. spinicauda n. sp. collected from soil around roots of mango were a medium-sized body, a tail mucro with 10 spines, and absence of lateral lines and crystalloids. Males were not found.     

Temperature Effects on Development and Reproduction of Heterodera cajani on Pigeonpea

Effects of constant and fluctuating temperature on development and reproduction of Heterodera cajani were studied on pigeonpea cv. ICPL 87 in growth chambers at 10, 15, 20, 25, and 30 C and in a greenhouse fluctuating between 22.2 and 37.8 C. Nematode penetration was greatest (P = 0.001) in roots at 25 C; there was no penetration at 10 C. The basal threshold temperature for development was calculated to be 11 C. Completion of one H. cajani generation required 17, 28, 35, and 66 days (323, 392, 315, and 264 degree-days) at 30, 25, 20, and 15 C, respectively, and 19 days (356 degree-days) at a fluctuating temperature. Survival was greater at 20 and 25 C than at 15 and 30 C. The greatest (P = 0.05) number of females (17.9 females per root) were produced at 25 C, compared with 13.2 at 20 C, 7.9 at 30 C, and 2.5 females at 15 C. Nematode reproduction was 1.6 to 7.1 times greater at 25 C than at other temperatures. Emergence of juveniles from egg sacs and cysts was greater at 25 and 30 C than at 15 and 20 C. Equations were developed to predict nematode development rate, cumulative juvenile emergence from egg sacs and cysts, and population increases as influenced by temperature.     

A Novel Photoaffinity Ligand for Kainate Sites Labels Two Polypeptides with Molecular Mass 45 and 33.5 kDa in Chick Cerebellum

Abstract: The synthesis of (2 S ,3 S ,4 S )-4-[1-(4-azidobenzamidomethyl)ethenyl]-2-carboxy-3-pyrrolidineacetic acid (ABCPA) is described. This novel kainic acid analogue, bearing a photolabile functionality on the isopropenyl side chain, was proven to be a good inhibitor of [³H]CNQX and [³H]kainic acid binding on chick cerebellar membranes. [³H]ABCPA was photoaffinity cross-linked on the membrane fraction of chick cerebellum. Electrophoretic analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed two major radioactive bands with apparent molecular masses of 45 and 33.5 kDa. [³H]ABCPA incorporation in both bands was completely blocked by 2 m M CNQX. When photoaffinity labeling was performed in the presence of 2 m M kainic acid, incorporation of [³H]ABCPA was blocked by ∼70% in the 45-kDa band and by 18% in the 33.5-kDa band. Incorporation of radioactivity in both bands was blocked by ∼30% with 10 m M glutamate.     

Chronic Administration of Lithium Chloride Increases Immunodetectable Glial Fibrillary Acidic Protein in the Rat Hippocampus

Abstract: We studied the effect of treating rats with lithium salts on the content and in vitro phosphorylation rate of the astrocyte cell marker, glial fibrillary acidic protein (GFAP), in brain slices. Rats were fed a diet incorporating lithium chloride until the concentration of Li⁺ in serum reached 0.6–1.2 m M , a range similar to that achieved in clinical practice. Hippocampal tissue was analyzed for immunoreactive GFAP by a dot assay, and slices of hippocampus and caudate nucleus were labeled with [³²P]-phosphate to determine the in vitro rate of phosphorylation of GFAP. Compared with controls, the level of immunoreactive GFAP in the hippocampus from lithium-treated rats was increased 34%, and GFAP in hippocampal slices incorporated 39% more ³²P. This effect of lithium was apparently not confined to the hippocampus because the in vitro rate of phosphorylation of GFAP in caudate slices was also increased in the treated rats.     

Activity of the tetramer and octamer of glutamine synthetase isoforms during primary leaf ontogeny of sugar beet (Beta vulgaris L.)

In extracts from the primary leaf blade of sugar beet (Beta vulgaris L.) we separated a chloroplastic isoform (GS 2) of glutamine synthetase (GS, EC 6.3.1.2) and one or two (depending on leaf age) cytosolic isoforms (GS 1a and GS 1b). The latter were prominent in the early (GS 1a) and late stages of leaf ontogeny (GS 1a and GS 1b), whereas during leaf maturation GS 2 was the predominantly active GS isoform. The GS 1 isoforms were active exclusively in the octameric state although tetrameric GS 1 protein was detected immunologically. Their activity stayed at a relatively constant level during leaf ontogeny; an increase was observed only in the senescent leaf. The activity of GS 2, however, changed drastically during primary leaf ontogeny and was modulated by changes in the oligomeric state of the active enzyme. In the early and late stages of leaf ontogeny when GS 2 activity was low (lower than that of the GS 1 isoforms), GS 2 was active only in the octameric state. In the maturing leaf, when GS 2 activity had reached its maximum level (much higher than that of the GS 1 isoforms), 80 of total GS 2 activity was due the activity of the tetrameric form of the enzyme and 20 was due to octameric GS 2. Tetrameric GS 2 was a hetero-tetramer and thus not the unspecific dissociation product of homo-octameric GS 2. In addition, GS 2 activity was modulated by an activation/inactivation of the tetrameric GS 2 protein. Due to an activation of the GS 2 tetramer, the activity of tetrameric GS 2 increased during leaf maturation from zero level 23-fold compared with that of GS 1a and 18-fold compared with that of GS 1b. Possible activators of tetrameric GS 2 are thiol-reactive substances. During leaf senescence, GS 2 activity decreased to zero; this decrease was due to an inactivation of the tetrameric GS 2 protein probably caused by oxidation.Abbreviations FLL final lamina length - FPLC fast protein liquid chromatography - GS glutamine synthetase - GHA -glutamyl hydroxamate - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase Dr. Roger Wallsgrove's (Rothamsted Experimental Station, Harpenden, UK) generous gift of GS antiserum is greatly appreciated.     

The incidence of mini- and micro-satellite repetitive DNA in the canine genome

We have estimated the incidence of microand mini-satellites in the dog genome. A genomic phage library from canine liver, with an average insert size of 16 kb, was screened to detect potentially polymorphic microand mini-satellite sequences, which may be useful for the development of markers of inherited diseases, for fingerprinting, or for population genetics. Synthetic oligonucleotide probes were used to search for microsatellite sequences, and minisatellites were investigated with eight heterologous VNTR probes. (CA)_n.(GT)_n sequences were by far the most frequent, with a calculated average distance between consecutive loci of 42 kb. The average distance between loci of tri- or tetra-nucleotide repeats was about 330 kb. Mean inter-locus distances were 320 kb for (GGC)_n, 205 kb for (GTG)_n, 563 kb for (AGG)_n, 320 kb for (TCG)_n, 233 kb for (TTA)_n, 384 kb for (CCTA)_n, 368 kb for (CTGT)_n, 122 kb for (TTCC)_n, 565 kb for (TCTA)_n, and 229 kb for (TAGG)_n. Cross-hybridization with eight human minisatellite probes was found at average distances of 1400 kb; only one did not hybridize at all. We conclude that the di-, tri and tetra-nucleotide short tandem repeats, as well as some minisatellite sequences, are potentially useful as genetic markers, for mapping of the canine genome, and also for paternity testing and the analysis of population characteristics.     

Implications of the variance effective population size on the genetic conservation of monoecious species

The concept of variance effective population size [Ne_(v)] and other expressions are reviewed and described for specific sampling steps in germplasm collection and regeneration of monoecious species. Special attention is given to procedures for computing the variance of the number of contributed gametes [V(k)] to the next generation. Drift, as it occurs between generations, was considered to contain a component due to the sampling of parents and a subsequent component due to the sampling of gametes. This demonstrates that drift, caused by reduction of seed viability, damages the genetic integrity of accessions stored in germplasm banks. The study shows how mating designs, such as plant-to-plant or chain crossings with additional female gametic control, can partially alleviate this problem. Optimal procedures for increasing Ne_(v) when collecting germplasm in the field are also discussed. The effect of different female and male gametic control strategies on Ne_(v) is considered under several situations. Practical examples illustrating the use of V(k) and Ne_(v) expressions are given.     

Genetic variation inMeloidogyne incognita virulence against the tomatoMi resistance gene: evidence from isofemale line selection studies

Resistance to the parthenogenetic root-knot nematodeMeloidogyne incognita is controlled in tomato by the single dominant geneMi, against which virulent pathotypes are able to develop. Isofemale lines (i.e., families) were established from a natural avirulent isolate ofM. incognita in order to study the genetic variability and inheritance of the nematode virulence. From the progeny of individual females, the production of egg masses on the root system of theMi-resistant tomato Piersol was analyzed in artificial selection experiments. A family analysis revealed, after two successive generations, a strongly significant variation between the 63 isofemale lines tested, and the results obtained for the mothers and their daughters were also significantly correlated. These results together clearly demonstrate the existence of a genetic variability and inheritance for this character. In a second experiment, a four-generation selection was performed on 31 other isofemale lines. The results revealed a significant response to selection apparently limited only to the two families able to produce, in first generation, a significant minimal egg-mass number on the resistant cultivar.