Occurrence, virulence gene and antimicrobial susceptibility profiles of Arcobacter sp. isolated from catla (Catla catla) in India.

In the present study, a total of 100 catla (Catla catla-major South Asian carp, local name botcha) collected from local fish markets and aquaculture ponds were subjected for isolation and characterization of Arcobacter sp. In all, 21 Arcobacter sp. were isolated, of which 18 (85·7%) were Arcobacter butzleri and three (14%) were A. cryoaerophilus as identified by multiplex PCR. All 18 A. butzleri isolates were positive for mviN, ciaB and tlyA virulence genes, three of A. cryoaerophilus isolates carried mviN gene and none of the isolates were positive for cadF, irgA, cj1349, hecA and hecB genes. All isolates (n = 21) were resistant to penicillin (100%). Meanwhile, 71·43, 23·81, 23·81, 14·29 and 9·52% of the isolates showed resistance towards vancomycin, nalidixic acid, erythromycin, cefixime and kanamycin, respectively. Multidrug resistance was observed in 23·81% of the Arcobacter sp. isolates and none of the isolates were positive for any of the extended spectrum beta-lactamases either by phenotypic or by molecular identification genes (blaOXA , blaSHV , blaTEM , blaCTX-M1 , blaCTX-M2 and blaCTX-M9 groups). The results emphasize the need to implement specific control procedures to reduce the use of antibiotics in aquaculture particularly the ones which are very important in human medicine. SIGNIFICANCE AND IMPACT OF THE STUDY: Arcobacter species are emerging food- and water-borne human pathogens. In this study, Arcobacter butzleri was predominant in fish compared to A. cryoaerohilus and A. skirrowii. Higher incidence of arcobacters in fish market samples suggests cross contamination and unhygienic handling of fish in markets. Virulence genes profile and antibiotics resistance of the Arcobacter sp. isolated in current study indicate pathogenic potential of Arcobacter sp. to humans. Occurrence of multidrug-resistant Arcobacter sp. in fish is a major concern in food safety. To our knowledge, this is the first report of Arcobacter sp. from freshwater fish, catla (Catla catla) in India.

Lateral parietal cortex in the generation of behavior: Implications for apathy.

A reduction in goal-directed behavior, or apathy, occurs in neurological and psychiatric disorders, though its neural substrates remain unclear. Deficits in circuits connecting the prefrontal cortex to subcortical regions are considered to underlie apathy. Although apathy is empirically associated with widespread changes in these regions, studies across disorders also link apathy with the lateral parietal cortex. Such variety in regional involvement is consistent with the established role of prefrontal and subcortical regions in models of goal-directed behavior, and with the suggestion of subtypes of apathy. However, these models do not provide a basis for the involvement of the lateral parietal cortex with apathy. Here, we review the association between lateral parietal cortex dysfunction and apathy across disorders and analyze the putative cognitive functions that may link this region with goal-directed behavior. We suggest that neural processes in the angular and supramarginal gyri of the inferior parietal lobule may provide an interface enabling the transformation of internal goals to external actions through intentional initiation of action interrelated with mechanisms of primary sensorimotor transformation. Consequently, we propose that impairment in this process of embedding intended action in a 'body schema' facilitating adequate recruitment of an effector system, is the likely mechanism underlying the association between the lateral parietal cortex and apathy. Considering the evidence, we propose a revised neurocognitive model of apathy where deficient internal initiation of behavior mediated by the inferior parietal lobule may be sufficient, though not necessary, to reduce goal-directed behavior, and may constitute a volitional subtype of apathy.

Virulence gene profiles of Arcobacter species isolated from animals, foods of animal origin, and humans in Andhra Pradesh, India.

AIM: This study aimed to detect putative virulence genes in Arcobacter species of animal and human origin. MATERIALS AND METHODS: A total of 41 Arcobacter isolates (16 Arcobacter butzleri, 13 Arcobacter cryaerophilus, and 12 Arcobacter skirrowii) isolated from diverse sources such as fecal swabs of livestock (21), raw foods of animal origin (13), and human stool samples (7) were subjected to a set of six uniplex polymerase chain reaction assays targeting Arcobacter putative virulence genes (ciaB, pldA, tlyA, mviN, cadF, and cj1349). RESULTS: All the six virulence genes were detected among all the 16 A. butzleri isolates. Among the 13 A. cryaerophilus isolates, cadF, ciaB, cj1349, mviN, pldA, and tlyA genes were detected in 61.5, 84.6, 76.9, 76.9, 61.5, and 61.5% of isolates, respectively. Among the 12 A. skirrowii isolates, cadF, ciaB, cj1349, mviN, pldA, and tlyA genes were detected in 50.0, 91.6, 83.3, 66.6, 50, and 50% of isolates, respectively. CONCLUSION: Putative virulence genes were detected in majority of the Arcobacter isolates examined. The results signify the potential of Arcobacter species as an emerging foodborne pathogen.

Intrathecal PKA-selective siRNA treatment blocks sustained morphine-mediated pain sensitization and antinociceptive tolerance in rats.

Sustained morphine treatment has been shown to produce paradoxical pain sensitization (opioid-induced hyperalgesia) and also causes increase in spinal pain neurotransmitter, such as calcitonin gene related peptide (CGRP), concentration in experimental animals. Studies have also shown that cyclic adenosine-monophosphate (cAMP)-dependent protein kinase (PKA) plays a major role in the regulation of presynaptic neurotransmitter (such as CGRP and substance P) synthesis and release. We have previously shown that in cultured primary sensory dorsal root ganglion (DRG) neurons sustained in vitro opioid agonist treatment upregulates cAMP levels (adenylyl cyclase (AC) superactivation) and augments basal and capsaicin evoked CGRP release in a PKA dependent manner. In the present study, we investigated the in vivo role of PKA in sustained morphine-mediated pain sensitization. Our data indicate that selective knock-down of spinal PKA activity by intrathecal (i.th.) pretreatment of rats with a PKA-selective small interference RNA (siRNA) mixture significantly attenuates sustained morphine-mediated augmentation of spinal CGRP immunoreactivity, thermal hyperalgesia, mechanical allodynia and antinociceptive tolerance. The present findings indicate that sustained morphine-mediated activation of spinal cAMP/PKA-dependent signaling may play an important role in opioid induced hyperalgesia.

Sustained morphine-mediated pain sensitization and antinociceptive tolerance are blocked by intrathecal treatment with Raf-1-selective siRNA.

BACKGROUND AND PURPOSE: Long-term morphine treatment enhances pain neurotransmitter [such as calcitonin gene-related peptide (CGRP)] levels in the spinal cord. It has been suggested previously that increased spinal CGRP may contribute to sustained morphine-mediated paradoxical pain sensitization and antinociceptive tolerance. Previous in vitro studies from our group indicated that Raf-1 kinase-mediated adenylyl cyclase superactivation played a crucial role in sustained morphine-mediated augmentation of basal and evoked CGRP release from cultured primary sensory neurons. The present study was aimed to evaluate the physiological significance of this molecular mechanism in vivo, in rats. EXPERIMENTAL APPROACH: Rats were intrathecally (i.th) injected with a Raf-1-selective small interfering RNA (siRNA) mixture for 3 days and were subsequently infused with saline or morphine, s.c. for 7 days. Thermal and mechanical sensory thresholds of the animals were assessed by daily behavioural tests. After final behavioural testing (day 6), spinal cords were isolated from each animal group and spinal CGRP and Raf-1 protein levels were measured using elisa and immunohistochemistry. KEY RESULTS: Selective knockdown of spinal Raf-1 protein levels by i.th Raf-1-selective siRNA pretreatment significantly attenuated sustained morphine-mediated up-regulation of CGRP immunoreactivity in the spinal cord of rats and prevented the development of thermal hyperalgesia, mechanical allodynia and antinociceptive tolerance. CONCLUSIONS AND IMPLICATIONS: Raf-1 played a significant role in sustained morphine-mediated paradoxical pain sensitization and antinociceptive tolerance in vivo. These findings suggest novel pharmacological approaches to improve the long-term utility of opioids in the treatment of chronic pain.

Functional selectivity in cannabinoid signaling.

Cannabinoid (CB) agonists exhibit numerous potentially useful pharmacological properties, but unwanted side effects limit their use in clinical practice. Thus, novel strategies are needed to identify potential CB pharmaceuticals with fewer side effects. Activated CB receptors initiate multiple parallel intracellular signal transduction cascades. In the present paper we will review experimental data indicating that structurally different classes of CB agonists may exhibit selectivity toward individual subsets of intracellular signaling pathways. In support of this, recent findings indicate that chemically distinct classes of CB agonists frequently differ in their rank order of potency to produce analgesia versus other central nervous system effects in vivo. Structurally different agonists were also found to differ in their abilities to activate individual G protein types in vitro. Since it was suggested earlier that structurally distinct CB agonists may interact differently with the CB receptors, it has been hypothesized that different classes of cannabinoid agonists may stabilize unique active CB receptor conformations, leading to functional selectivity in CB receptor signaling. In order to obtain a direct proof for this hypothesis, we recently employed a highly sensitive biophysical method, plasmon-waveguide resonance (PWR) spectroscopy. PWR experiments have provided a direct proof that structurally different CB agonists produce qualitatively distinct changes in the shape and/or membrane orientation of the CB1 receptors, leading to functional selectivity in G protein activation. We expect that by identification of CB agonists that selectively activate preferred intracellular signaling pathways novel pharmacological lead structures can be identified for the design of improved CB analgesics with fewer side effects.