P3 P4 Research Articles

On the morphology and geographical distribution of some problematic South Palearctic Cyclops (Copepoda: Cyclopidae)

Females and males of two South Palearctic Cyclops, C. ankyrae Mann, 1940 and C. abyssorum divergens Lindberg, 1936 are redescribed, and their taxonomic relationships are discussed. Cyclops ankyrae can be distinguished from congeners by the spine formula of the terminal exopodal segments (2433), distinct anal operculum, bare proctodeum, presence of a longitudinal row of large spinules near the palp on the frontal surface of the mandibular coxopodite, spinule ornamentation of the maxilliped coxopodite, presence of hairs on the caudal surface of P3–P4 couplers, and lack of large spinules on the frontal surface of the P1 basipodite. Cyclops abyssorum divergens differs from C. abyssorum s. str. in the relatively short inner median caudal seta, reduced spinule ornamentation on the caudal surface of P4 coxopodite, and presence of large spinules on the maxillular palp. Cyclops singularis Einsle, 1996 is synonymized here with C. a. divergens Lindberg, 1936. The geographic distribution of C. a. divergens is revised.

Postnatal changes in the expression of serotonin 2A receptors in various brain stem nuclei of the rat

Previously, we reported a critical period [around postnatal day (P) 12-13 in the rat] in respiratory network development when distinct neurochemical, metabolic, and physiological changes occur. Since serotonin 2A (5-HT(2A)) receptors play an important role in respiratory modulation, we hypothesized that they may undergo developmental adjustments during the critical period. Semi-quantitative immunohistochemical analyses were conducted in labeled neurons in a number of brain stem nuclei with or without known respiratory functions from P2 to P21 in rats. Our data indicate that the expressions of 5-HT(2A) receptors in neurons of the pre-Bötzinger complex, the nucleus ambiguus, and the hypoglossal nucleus were maintained within a relatively narrow range between P2 and P21, with a dip at P3-P4 and a significant reduction only at P12. This change was not observed in the nonrespiratory cuneate nucleus. These results suggest that reduced expressions of 5-HT(2A) receptors at P12 contributes to neurochemical imbalance within brain stem respiratory nuclei at that time and may be involved in decreased hypoxic ventilatory response at this critical period of development.

A new species of Huntemannia (Copepoda: Harpacticoida: Huntemanniidae) from the Yellow Sea, Korea

Huntemannia doheoni sp. nov. is described from a muddy sand flat off the coast of the Yellow Sea, Korea. The new species can be distinguished from its congeners by a combination of characters that include: a strong, hook-like outer process on the P1 coxa; incompletely fused exopod segments and reduced setal formulae of the P2–P4 in the female; and modified outermost spine on the distal segment of P3–P4 in the male. In addition, a key to the species of Huntemannia is provided.

Deep levels in GaAs/Al 0.78Ga 0.22As heterostructures

A preliminary study of growth interruption effects on the GaAs/AlGaAs layers is reported. Deep level transient spectroscopy (DLTS) is performed on Al Schottky barrier devices fabricated on Si-doped, isotype GaAs/Al 0.78Ga 0.22As heterostructures grown by molecular beam epitaxy (MBE), both with (200 s) and without, growth interruption. Our spectra extending from ∼15 to 300 K show four peaks corresponding to deep level defects with thermal activation energies ( E A): 0.09, 0.32, 0.42 and 0.52 eV, which are detected in both types of samples (close to and) above liquid nitrogen temperature, although with different relative concentrations. Comparison with reported work on GaAs/Al x Ga 1− x As samples with different compositions ( x) shows that latter two of these deep levels are counterparts of the levels, P3–P4, earlier observed in MBE grown Al x Ga 1− x As materials with Al content different than that used here. However, the deep level spectra of our samples show dramatic differences for the growth interrupted and uninterrupted samples in the temperature range below 77 K. Whereas the samples prepared without growth interruption show a prominent, hitherto unobserved, positive (majority carrier emission) peak, P0 ( E A=0.029 eV), with shoulders on both higher and lower temperature flanks, the samples with growth interruption show a pronounced negative peak, apparently corresponding to a deep level with E A=0.031 eV, in the same temperature region, under similar measurement conditions. The deep-level characteristics, including emission rate signatures and apparent capture cross-sections, are determined for the observed features using the thermal emission rate data. Some interesting additional features related to depth profiles of deep levels, bias effects and charge-induced metastability effects are also reported.

Visual event-related potentials in elite and amateur athletes

In the present study, we tested the hypothesis that the neural synchronization estimated in visual cortex during visuo-spatial demands shows different features in elite karate athletes when compared to amateur karate athletes and non-athletes. EEG recordings (56 channels; EB-Neuro) were performed from 17 elite karate athletes, 14 amateur karate athletes, and 15 non-athletes, during the observation of pictures with basket and karate attacks. They clicked a right (left) keyboard button for basket or karate attacks at right (left) monitor side. Results pointed to no difference of late occipital VEPs/ERPs after basket versus karate attacks in the non-athletes (300–800 ms post-stimulus). In the amateur karate athletes, occipital VEPs/ERPs at 300–450 ms post-stimulus (P3–P4 components) were lower in amplitude for the karate than basket attacks. In the elite karate athletes, the occipital VEPs/ERPs further declined in amplitude at 300–450 ms post-stimulus (P3 and P4 components) and enhanced at about 800 ms post-stimulus (“N2” component) for the karate than basket attacks. A control study showed that in 10 elite fencers, the same was true for the fencing compared to the karate attacks. These results support the hypothesis that peculiar mechanisms of occipital neural synchronization can be observed in elite athletes during visuo-spatial demands, possibly to underlie sustained visuo-spatial attention and self-control.

The role of SHIP1 in T-lymphocyte life and death

SHIP1 [SH2 (Src homology 2)-containing inositol phosphatase-1], an inositol 5-phosphatase expressed in haemopoietic cells, acts by hydrolysing the 5-phosphates from PtdIns(3,4,5)P(3) and Ins(1,3,4,5)P(4), thereby negatively regulating the PI3K (phosphoinositide 3-kinase) pathway. SHIP1 plays a major role in inhibiting proliferation of myeloid cells. As a result, SHIP1(-/-) mice have an increased number of neutrophils and monocytes/macrophages due to enhanced survival and proliferation of their progenitors. Although SHIP1 contributes to PtdIns(3,4,5)P(3) metabolism in T-lymphocytes, its exact role in this cell type is much less explored. Jurkat cells have recently emerged as an interesting tool to study SHIP1 function in T-cells because they do not express SHIP1 at the protein level, thereby allowing reintroduction experiments in a relatively easy-to-use system. Data obtained from SHIP1 reintroduction have revealed that SHIP1 not only acts as a negative player in T-cell lines proliferation, but also regulates critical pathways, such as NF-kappaB (nuclear factor kappaB) activation, and also appears to remarkably inhibit T-cell apoptosis. On the other hand, experiments using primary T-cells from SHIP1(-/-) mice have highlighted a new role for SHIP1 in regulatory T-cell development, but also emphasize that this protein is not required for T-cell proliferation. In support of these results, SHIP1(-/-) mice are lymphopenic, suggesting that SHIP1 function in T-cells differs from its role in the myeloid lineage.

Triphenylphosphane‐Functionalised Amphiphilic Copolymers: Tailor‐Made Support Materials for the Efficient and Selective Aqueous Two‐Phase Hydroformylation of 1‐Octene

Amphiphilic copolymers (random P1 and block P2) based on 2-oxazolines were synthesised with triphenylphosphane ligands covalently linked to the polymers by means of a metal-free synthesis route. The resulting macroligands were used in the aqueous two-phase hydroformylation of 1-octene. The influence of the polymer architecture (random and block copolymers) on activity and selectivity of the hydroformylation reaction was investigated and compared with that of nonfunctionalised copolymers (random P3 and block P4) and Rh(I)/triphenylphosphane trisulfonate as a water-soluble catalyst. The highest activities were observed for the random copolymer P1 (p=50 bar, T=100 degrees C, c=8 x 10(-4) mol L(-1)) with a turnover frequency (TOF) of 3700 h(-1), whereas the corresponding block copolymer P2 reached TOF numbers of 1630 h(-1). Additionally, both macroligands indicated efficient suppression of isomerisation and led to almost constant n/iso selectivities of about 3 after complete substrate conversion. Copolymers P3 and P4 showed, under identical reaction conditions, strong isomerisation after 40-60 % conversion (n/iso approximately 0.7) and maximum activities of 1560 h(-1) (P3) and 1330 h(-1) (P4) at a concentration of 5 x 10(-3) mol L(-1).

Postnatal switching of NMDA receptor subunits from NR2B to NR2A in rat facial motor neurons

The subunit composition of N-methyl-D-aspartate (NMDA) receptors affects their function under normal and pathological conditions. Functional NMDA receptors are expressed in lower motor neurons, but their subunit composition has not been defined. Here, we employed electrophysiology, quantitative PCR, and immunohistochemistry to investigate the subunit composition of NMDA receptors in postnatal motor neurons of the Wistar rat facial nucleus (FN). Whole-cell patch clamp recordings of acutely dissociated motor neurons from postnatal days 3 and 4 (P3-P4) showed that ifenprodil, a specific antagonist of the NMDA receptor 2B (NR2B) subunit, inhibited 91.62%+/-2.02% of NMDA-induced current, whereas NVP-AAM007, a specific antagonist of the NMDA receptor 2A (NR2A) subunit, inhibited much less of the current (16.69%+/-3.28%). Starting from P5, the inhibitory effects of ifenprodil and NVP-AAM007 gradually decreased and increased, respectively, such that the effect of NVP-AAM007 exceeded that of ifenprodil by P10. At P14, most of the NMDA-induced current was inhibited by NVP-AAM007 (84.59%+/-3.35%). Consistent with this, NR2B mRNA and protein were expressed highly at P3 and then gradually decreased by more than 75% by P14 in FN motor neurons, while NR1 was expressed stably over the same ages. However, NR2A mRNA and protein showed relatively constant levels between P3-P10 and decreased to 45% and 75% of the P3 level, respectively, by P14. Thus, analysis of functional NMDA receptors is critical to revealing subunit switching, which may be an important step in postnatal development of FN motor neurons.

Carraroenia ruthae gen. et sp. nov. (Copepoda, Harpacticoida, Laophontidae) from maerl substrates of the Irish west coast

Carraroenia ruthae gen. et sp. nov. is described from maerl beds at An Dóilín, Carraroe, County Galway, Ireland. This genus is considered to be closely related to the genus group comprising Psammplatypus, Coullia, Phycolaophonte, Hemilaophonte and Robustunguis, which had been linked based on the reduced P2 endopod and the primitive setation of the male P5 baseoendopod. Carraroenia is regarded as the most primitive genus of this lineage, as evidenced by the 3segmented male P3 endopod, the lack of reduction in the P3–P4 endopods, the retention of the inner seta on P2–P4 exp-2 and the presence of 2 inner setae in P4 enp-2.

A Comparative Study on Luminescent Copolymers of Fluorene and Carbazole with Conjugated or δ-Si Interrupted Structures: Steric Effects

Light-emitting alternating copolymers of 9,9-dialkylfluorene and N-hexylcarbazole with conjugated (P1 and P2) and δ-Si interrupted (P3 and P4) structures have been synthesized. The linear tetrahedral polymer P3 and hyperbranched tetrahedral polymer P4 were synthesized from two novel tetrahedral dibromo/tetrabromo precursors (2 and 3, respectively). The thermal and optical properties of all polymers in solution and the condensed state were investigated. A comparative study on the optical properties of P1−P4 showed that, in the condensed state, P1 and P2 suffered seriously from concentration quenching (significant red shift in emission maximum, broadening in emission spectrum and tremendous decrease in quantum yield), whereas the two δ-Si interrupted P3 and P4, particularly the latter, were tremendously less or not prone to self-aggregation such that they did not show significant concentration quenching in the condensed state. We represent in this paper an effective approach, a tetrahedral approach, for the synthesis of nonaggregating optoelectronic polymers.

WINDOWS ON THE EVOLUTION OF PICRODUS (PLESIADAPIFORMES: PRIMATES): MORPHOLOGY AND RELATIONSHIPS OF A SPECIES COMPLEX FROM THE PALEOCENE OF ALBERTA

Since 1908, the peculiar North American primate Picrodus Douglass, 1908 (Picrodontidae; Plesiadapiformes) has been thought to contain only a single species, P. silberlingi Douglass, 1908, of late Paleocene age. However, new collections from the Paskapoo Formation, Alberta, Canada, reveal that instead a rich complex of Picrodus species lived during the Paleocene. Three of these, Picrodus calgariensis, P. canpacius, and P. lepidus, are described herein as new. Others, represented by more fragmentary specimens from Canada and the United States, are included in this paper, but are not named. P. calgariensis, from Who Nose? (late Torrejonian), Calgary, is the most primitive known species of Picrodus, having molars with little crenulation of the enamel. P. canpacius, from Cochrane 2 (earliest Tiffanian), northwest of Calgary, most resembles P. silberlingi sensu stricto, but differs in P4 structure, denser enamel crenulation, and weaker molar cusps. P. lepidus, from DW-2 (middle Tiffanian), near Red Deer, is the most advanced, having, for example, a two-rooted P4, tiny p3, and single-rooted p4. At least two of these species also occur in the United States, documented by fossils referred to P. silberlingi by previous workers. Dental evolution within Picrodus seems marked by several trends, including increase in size of i1, simplification of P4, reduction of molar cusps and crests, enlargement of the horizontal occlusal surfaces of the molars, and greater crenulation of enamel. From present knowledge, Zanycteris paleocenus Matthew, 1917 is dentally more primitive than Picrodus, Draconodus Tomida, 1982 is a valid genus, and picrodontids probably originated from “purgatoriid-grade” plesiadapiforms in earliest Paleocene time.

Inositol Phosphate Profiling of Fermented Cowpeas by 1H NMR Spectroscopy

The inositol phosphate content of naturally fermented cowpeas (Vigna sinensis var. Carilla) was studied using ion-pair HPLC and 1H NMR spectroscopy. The fermented flour was extracted with 0.5 M HCl, and the extract was purified and fractionated by ion-exchange chromatography. 1H NMR allowed for the identification of two monophosphates [Ins(1 or 3)P1 and Ins(4 or 6)P1], one inositol diphosphate [Ins(1,4)P2], three inositol triphosphates [Ins(1,2,6)P3, Ins(1,5,6)P3, and Ins(1,4,5)P3], one inositol tetraphosphate [Ins(1,3,4,5)P4], and one inositol pentaphosphate [Ins(1,2,3,5,6)P5]. Some of these isomers [Ins(1,4,5)P3 and Ins(1,3,4,5)P4] are considered to play important biological roles in intracellular signaling.

EEG Coherence Analysis in Never-Medicated Patients with Panic Disorder

To investigate the functional abnormalities in the central nervous system (CNS) of patients with panic disorder (PD), we compared the electroencephalography (EEG) coherence values in 18 never-medicated PD patients with those in age-matched normal control subjects, and examined the relationships between EEG coherence values and both the duration of disease and the severity of panic attacks. EEG data were recorded in the resting state. The PD patients had lower coherence values with significant differences in F3-F4, C3-C4, P3-P4, F7-T5, and F8-T6. There were positive correlations for the higher alpha band between coherence values and both the duration of disease and the severity of panic attacks. These findings provide further evidence that PD patients have a lower degree of inter-hemispheric functional connectivity in the frontal region and intra-hemispheric functional connectivity in the bilateral temporal region, and that chronic condition or frequent panic attacks in PD patients may be related to the pathophysiological CNS changes.

Postnatal changes in cytochrome oxidase expressions in brain stem nuclei of rats: implications for sensitive periods.

Previously, we reported that cytochrome oxidase (CO) activity in the rat pre-Bötzinger complex (PBC) exhibited a plateau on postnatal days (P) 3-4 and a prominent decrease on P12 (Liu and Wong-Riley, J Appl Physiol 92: 923-934, 2002). These changes were correlated with a concomitant reduction in the expression of glutamate and N-methyl-d-aspartate receptor subunit 1 and an increase in GABA, GABAB, glycine receptor, and glutamate receptor 2. To determine whether changes were limited to the PBC, the present study aimed at examining the expression of CO in a number of brain stem nuclei, with or without known respiratory functions from P0 to P21 in rats: the ventrolateral subnucleus of the solitary tract nucleus, nucleus ambiguus, hypoglossal nucleus, nucleus raphe obscurus, dorsal motor nucleus of the vagus nerve, medial accessory olivary nucleus, spinal nucleus of the trigeminal nerve, and medial vestibular nucleus (MVe). Results indicated that, in all of the brain stem nuclei examined, CO activity exhibited a general increase with age from P0 to P21, with MVe having the slowest rise. Notably, in all of the nuclei examined except for MVe, there was a plateau or decrease at P3-P4 and a prominent rise-fall-rise pattern at P11-P13, similar to that observed in the PBC. In addition, there was a fall-rise-fall pattern at P15-P17 in these nuclei, instead of a plateau pattern in the PBC. Our data suggest that the two postnatal periods with reduced CO activity, P3-P4 and especially P12, may represent common sensitive periods for most of the brain stem nuclei with known or suspected respiratory control functions.

The oldest Camelidae (Mammalia, Artiodactyla) of Africa : new finds from the Mio-Pliocene boundary, Chad

The oldest Camelidae (Mammalia, Artiodactyla) of Africa : new finds from the Mio-Pliocene boundary, Chad

Sorting the Sheep from the Goats: Morphological Distinctions between the Mandibles and Mandibular Teeth of AdultOvis and Capra

Diagnostic criteria are described for the taxonomic discrimination of adult mandibles of sheep (Ovis aries) and goat (Capra hircus). These criteria, based on morphological distinctions in the mandible, permanent premolars (P3–P4) and molars (M1–M3), have been successfully tested on a large and diverse body of modern reference material. In conjunction with published work on deciduous premolars, the new criteria enable complete and fragmentary mandibles of young, adult and elderly individuals to be identified to sheep or goat with acceptable levels of accuracy.

Agonist-specific maturation of GIRK current responses in acutely isolated pyramidal neurons of rat neocortex

We performed whole-cell recordings from acutely isolated pyramidal cell somata of rat neocortex to measure and compare G protein-activated, inwardly rectifying K + (GIRK) currents induced by adenosine, serotonin and baclofen at different postnatal stages (postnatal days 3–19). In about two thirds of neurons, baclofen-induced GIRK currents were already detected at postnatal days 3 and 4 (P3–P4) and almost all neurons between P5 and P19 were responsive. This robust response suggests that postsynaptic effects of baclofen occur much earlier than previously thought. Sensitivity to adenosine was around 70% during the first two postnatal weeks. Given the late maturation of functional synaptic inhibition in neocortex, we propose that phasic and/or tonic activation of GIRK current by baclofen and adenosine might serve as a mechanism to control neuronal excitability during early postnatal development. In marked contrast to the pronounced early sensitivity to baclofen and adenosine, only 20% of the neurons displayed a GIRK current response to serotonin during the first postnatal week. After that, about half of the neurons tested positive for serotonin. GIRK current densities for baclofen and adenosine attained a maximum at the end of the second postnatal week, whereas the serotonin-induced current showed a linear increase during the second and third week of life. Set in relationship with previous data on the postnatal expression of receptor protein and GIRK channel mRNA, our findings suggest that the maturation of GIRK current responses is determined predominantly by the different postnatal patterns of receptor expression.

Stereoselective synthesis of 2,6-dideoxy; 3,6-dideoxy; 2,3,6-trideoxy-inositol 1,4,5-trisphosphate and 6-deoxy-inositol 1,3,4,5-tetrakisphosphate analogues from 6-deoxy-d-inositol precursors

The novel 2,6-dideoxy-2,2-difluoro; 2,6-dideoxy-2-fluoro; and 2,3,6-trideoxy-2,3-difluoro-Ins(1,4,5)tris(dibutyl)phosphates and 6-deoxy-d-chiro-inositol 1,3,4,5-tetrakis(dibutyl)phosphate analogues were synthesized in optically pure form. Modification of Ins(1,4,5)P3 and Ins(1,3,4,5)P4 analogues by lipophilic substituents has been investigated in order to produce neutral phosphate derivatives aimed to be incorporated in cell membrane for in vivo evaluation.

Development of Astroglial Elements in the Suprachiasmatic Nucleus of the Rat: With Special Reference to the Involvement of the Optic Nerve

The development of astroglial cells and the effect of the retinohypothalamic tract on it were studied by vimentin and glial fibrillary acidic protein (GFAP) immunocytochemistry in the suprachiasmatic nucleus (SCN) of the rat. At the embryonic stage, vimentin-immunoreactive (VIM-IR) radial glia, precursors of astrocytes, were dominant. However, their filaments vanished in the first few postnatal days. Instead of VIM-IR glial filaments, GFAP-immunoreactive (GFAP-IR) astrocytes appeared at E20 and grew rapidly from the P3 stage. GFAP immunoreactivity in the ventrolateral portion of the SCN (VLSCN) was measured using a computer-assisted image analyzing system. In normal rats, GFAP immunoreactivity showed a stepwise pattern with two slopes at P3–P4 and P20–P25. Bilaterally eye-enucleated rats operated on the day of birth showed lower GFAP immunoreactivity than normal rats and the GFAP immunoreactivity did not increase between P20 and P25 when GFAP-IR glial processes rapidly expand. Electron microscopic investigation at P50 (adult stage) revealed that neurons in the VLSCN had often direct apposition without astroglial processes and the frequency of this finding was significantly higher in eye-enucleated rats than in the control rats. These findings strongly suggest that the postnatal development of astroglial elements, particularly the expansion of GFAP-IR processes in the SCN, is regulated by retinohypothalamic projection.

Multitasking in signal transduction by a promiscuous human Ins(3,4,5,6)P4 1-kinase/Ins(1,3,4)P3 5/6-kinase

We describe a human cDNA encoding 1-kinase activity that inactivates Ins(3,4,5,6)P4, an inhibitor of chloride-channel conductance that regulates epithelial salt and fluid secretion, as well as membrane excitability. Unexpectedly, we further discovered that this enzyme has alternative positional specificity (5/6-kinase activity) towards a different substrate, namely Ins(1,3,4)P3. Kinetic data from a recombinant enzyme indicate that Ins(1,3,4)P3 (Km = 0.3µM; Vmax = 320 pmol/min per µg) and Ins(3,4,5,6)P4 (Km = 0.1µM; Vmax = 780pmol/min per µg) actively compete for phosphorylation in vivo. This competition empowers the kinase with multitasking capability in several key aspects of inositol phosphate signalling.