Development of Anxiolytic and Depression-like Behavior in Mice Infected with Mycobacterium lepraemurium.

Murine leprosy is a systemic infectious disease of mice caused by Mycobacterium lepraemurium (MLM) in which the central nervous system (CNS) is not infected; nevertheless, diseased animals show measurable cognitive alterations. For this reason, in this study, we explored the neurobehavioral changes in mice chronically infected with MLM. BALB/c mice were infected with MLM, and 120 days later, the alterations in mice were evaluated based on immunologic, histologic, endocrine, neurochemical, and behavioral traits. We found increases in the levels of IL-4 and IL-10 associated with high bacillary loads. We also found increase in the serum levels of corticosterone, epinephrine, and norepinephrine in the adrenal gland, suggesting neuroendocrine deregulation. Mice exhibited depression-like behavior in the tail suspension and forced swimming tests and anxiolytic behavior in the open field and elevated plus maze tests. The neurobehavioral alterations of mice were correlated with the histologic damage in the prefrontal cortex, ventral hippocampus, and amygdala, as well as with a blood-brain barrier disruption in the hippocampus. These results reveal an interrelated response of the neuroimmune--endocrinological axis in unresolved chronic infections that result in neurocognitive deterioration.

Humulus japonicus rescues autistic­like behaviours in the BTBR T+ Itpr3tf/J mouse model of autism.

Humulus japonicus (HJ) is a traditional herbal medicine that exhibits anti­inflammatory, antimicrobial and anti­tumor effects that is used for the treatment of hypertension, pulmonary disease and leprosy. Recently, it has also been reported that HJ demonstrates neuroprotective properties in animal models of neurodegenerative diseases. The current study hypothesised that the administration of HJ would exhibit therapeutic effects in autism spectrum disorder (ASD), a neurodevelopmental disorder with lifelong consequences. The BTBR T+ Itpr3tf/J mouse model of ASD was used to investigate the anti­autistic like behavioural effects of HJ. Chronic oral administration of the ethanolic extract of HJ significantly increased social interaction, attenuated repetitive grooming behaviour and improved novel­object recognition in BTBR mice. Anti­inflammatory effects of HJ in the brain were analysed using immunohistochemistry and reverse­transcription quantitative PCR analysis. Microglia activation was markedly decreased in the striatum and hippocampus, and pro­inflammatory cytokines, including C­C Motif Chemokine Ligand 2, interleukin (IL)­1ß and IL­6, were significantly reduced in the hippocampus following HJ treatment. Moreover, HJ treatment normalised the phosphorylation levels of: N­methyl­D­aspartate receptor subtype 2B and calcium/calmodulin­dependent protein kinase type II subunit α in the hippocampus of BTBR mice. The results of the present study demonstrated that the administration of HJ may have beneficial potential for ameliorating behavioural deficits and neuroinflammation in ASD.

Disruption of LRRK2 in Zebrafish leads to hyperactivity and weakened antibacterial response.

As a protein with complex domain structure and roles in kinase, GTPase and scaffolding, LRRK2 is believed to be an important orchestration node leading to several cascades of signal transduction rather than one specific pathway. LRRK2 variants were found to be associated with Parkinson's disease, Crohn's disease and leprosy. Here we disrupt LRRK2 in zebrafish and found hyperactivity rather than hypoactivity in adult zebrafish mutants. By RNA-seq we found genes involved in infectious disease and immunological disease were notably affected. Functional studies also revealed a weakened antibacterial response in LRRK2 mutant. This mutant can be further explored for revealing molecular mechanisms and modeling of LRRK2 related diseases.

Reproductive state affects hiding behaviour under risk of predation but not exploratory activity of female Spanish terrapins.

Female investment during reproduction may reduce survivorship due to increased predation risk. During pregnancy, the locomotor performance of gravid females might be diminished due to the additional weight acquired. In addition, egg production may also increase thermoregulatory, metabolic and physiological costs. Also, pregnant females have greater potential fitness and should take fewer risks. Thus, females should ponder their reproductive state when considering their behavioural responses under risky situations. Here, we examine how reproductive state influence risk-taking behaviour in different contexts in female Spanish terrapins (Mauremys leprosa). We simulated predator attacks of different risk levels and measured the time that the turtles spent hiding entirely inside their own shells (i.e. appearance times). We also assessed the subsequent time after emergence from the shell that the turtles spent immobile monitoring for predators before starting to escape actively (i.e. waiting times). Likewise, we performed a novel-environment test and measured the exploratory activity of turtles. We found no correlations between appearance time, waiting time or exploratory activity, but appearance times were correlated across different risk levels. Only appearance time was affected by the reproductive state, where gravid females reappeared relatively later from their shells after a predator attack than non-gravid ones. Moreover, among gravid females, those carrying greater clutches tended to have longer appearance times. This suggests that only larger clutches could affect hiding behaviour in risky contexts. In contrast, waiting time spent scanning for predators and exploratory activity were not affected by the reproductive state. These differences between gravid and non-gravid females might be explained by the metabolic-physiological costs associated with egg production and embryo maintenance, as well as by the relatively higher potential fitness of gravid females.

Feeding status and basking requirements of freshwater turtles in an invasion context.

Thermoregulatory behavior and feeding status are strongly related in ectotherms. A trade-off between maintenance of energy balance and digestion efficiency has been recently proposed to affect thermoregulation in these animals. On the other hand, competition for basking sites has been described between Iberian turtles and the introduced red-eared slider (Trachemys scripta elegans). T. scripta negatively interferes with basking behavior of native turtles and benefits from a greater capacity to retain body heat, which may likely result in thermoregulatory advantages for the introduced sliders. Consequently, complex effects and alterations in metabolic rates of native turtles might derive from a deficient basking behavior. We compared the basking requirements of the endangered native Spanish terrapin (Mauremys leprosa) and those of the introduced red-eared slider, analyzing the upper set point temperature (USP) (defined as the body temperature at which basking ceased) of both native and introduced turtles, under feeding and fasting conditions. We found higher values of USP in the native species, and a reduction of this temperature associated with food deprivation in the two turtle species. This adjustment of thermoregulatory behavior to the nutritional status found in freshwater turtles suggests that ectotherms benefit from metabolic depression as an adaptive mechanism to preserve energy during periods of fasting. However, a reduction in metabolic rates induced by competition with sliders might lead M. leprosa to a prolonged deficiency of their physiological functions, thus incurring increased predation risk and health costs, and ultimately favoring the recession of this native species in Mediterranean habitats.

Effects of genetic selection on behavioral profiles of Single Comb White Leghorn hens through two production cycles.

Four layer genetic stocks consisting of 3 Ottawa control strains (5, 7, and 10) and a commercial laying stock (CCS) were utilized to evaluate potential changes in behavioral profiles due to the effects of genetic selection through 2 production cycles. The Ottawa strains were started as random bred strains from the crosses of several popular commercial layers in 1950, 1959, and 1972, and the commercial strain used herein was from calendar year 1993, and its ancestors were involved in the formation of all of the random bred strains. The behavior study utilized 2 replicates from each strain that contained 4 cages, 6 hens/cage, for a total of 192 hens. Behavioral observations were recorded on 2 consecutive days beginning at 22 wk of age and every 28 d thereafter during the first production cycle, the molt period, and the second production cycle through 90 wk of age and periodic feather and Hansen's test scores recorded. Behavior profiles were similar between the control strains and the CCS, indicating that long-term genetic selection by commercial egg-type breeding firms to enhance production parameters has had no impact on laying strain behavior patterns. Appetitive behaviors were not affected by strain. During the molt, hens had reduced (P < 0.05) feeding and drinking frequencies in comparison with those observed during the first and second cycles. The data indicated that hens pecked inedible objects at a greater (P < 0.0001) frequency during the first cycle and molt than during the second cycle. Fearfulness scores were only influenced by production phase with the molt having the highest (P < 0.01) score of 3.46. Strain or production phase did not influence the frequency of aggressive and submissive acts.

Nerve damage in Mycobacterium ulcerans-infected mice: probable cause of painlessness in buruli ulcer.

Buruli ulcer is an emerging chronic painless skin disease found in the tropics and caused by Mycobacterium ulcerans; however, it remains unknown why the large and deep ulcers associated with this disease remain painless. To answer this question, we examined the pathology of BALB/c mice inoculated in the footpads with M. ulcerans African strain 97-107. On days 54 to 70 after inoculation, extensive dermal ulcers, subcutaneous edema, and numerous acid-fast bacilli were noted at the inoculate region. Nerve invasion occurred in the perineurium and extended to the endoneurium, and some nerve bundles were swollen and massively invaded by acid-fast bacilli. However, Schwann cell invasion, a characteristic of leprosy, was not observed. Vacuolar degeneration of myelin-forming Schwann cells was noted in some nerves which may be induced by mycolactone, a toxic lipid produced by M. ulcerans. Polymerase chain reaction analysis of microdissected nerve tissue sections showed positive amplification of M. ulcerans-specific genomic sequences but not of Mycobacterium leprae-specific sequences. Behavioral tests showed decrease of pain until edematous stage, but markedly ulcerated animals showed ordinary response against stimulation. Our study suggests that the painlessness of the disease may be partly due to intraneural invasion of bacilli. Further studies of nerve invasion in clinical samples are urgently needed.

The effects of different beak trimming techniques on plasma corticosterone and performance criteria in Single Comb White Leghorn hens.

DeKalb XL chicks were given a beak trim at 6 d of age (6DP) with a 2.8-mm gauge and a beak trim at 11 wk (11WB) with a block cut approximately 2 mm anterior to the nasal openings. Corticosterone (CS) levels of the 6DP treatment were (P < or = 0.01) elevated above nontrimmed CS levels at 2 h posttrim; and BW and feed consumption (FC) of the 6DP were depressed until 8 wk of age. At 11 wk of age, CS of the 11WB treatment was (P < or = 0.02) elevated above controls at 1, 2, 8, and 5 wk posttrim. The 11WB treatment resulted in a decrease in FC and a reduction in BW at 12, 14, and 16 wk of age, whereas there were no differences among treatments in livability during the pullet phase. At 72 wk of age, FC of the nontrimmed controls was greater than both beak trimmed treatments, and both beak trimmed treatments had greater hen housed eggs, percentage hen day egg production, and percentage livability. Both beak trimmed treatments resulted in better egg income, feed cost per hen, and net income (NI). The 6DP and 11WB beak trim treatments resulted in an improvement of NI per hen of 1.48 dollars and 1.86 dollars, respectively. In addition, both beak trimmed treatments exhibited better feather score and Hansen's test (fearfulness). It was concluded that pullets and hens could adapt to the physiological stress of beak trimming and out perform, during a lay phase, controls whose beaks were not trimmed.

Effects of bird age, density, and molt on behavioral profiles of two commercial layer strains in cages.

Two commercial strains, Hy-Line W-36 and DeKalb XL, were moved to a laying house at 18 wk of age. They were housed 6 hens/layer cage at 2 densities (361 and 482 cm2/bird) with 2 replications each per strain/density combination. The high-density treatment contained 24 hens/replication and the low-density treatment contained 18 hens/replication for a total of 168 hens. Production parameters were measured during the first egg production cycle, the molt period, and the first 4 wk of the second lay cycle (20 to 68 wk of age). Behavioral observations were taken during 2 consecutive d at 26, 34, 43, 51, 62, 64, and 68 wk of age to examine behavioral patterns. Modified Hansen's tests were conducted concurrently to provide indication of the fearfulness levels of hens at the various stages of production. The production characteristics were similar for both strains. The hens kept at the higher density had lower (P < 0.01) hen-day production and (P < 0.05) daily egg mass. Appetitive behaviors were not affected by strain or density but were affected by the age of the hen and by molting. During the molt, feeding and drinking behavioral acts were fewer (P < 0.05) at 0.018 and 0.013 acts per bird/min, respectively, and standing behavior was highest. The results indicated that the frequencies of pecking inedible objects during the molt period were similar to the frequencies at 26 and 34 wk. Hens performed more acts of standing, and crouching and had lower frequency of movement during the molt. Those kept at a low density performed more movement acts. Feather pecking decreased as hens aged and increased when they molted but was not affected by strain or density. The frequency of aggression and submissive acts was significantly lower during the molt period. Behaviors were affected by strain, density, bird age, and molting; however, the patterns and number of aggressive acts did not increase to compromise the welfare status of the hens. Behaviors during the molt appeared consistent with mechanisms for conservation of body reserves.

Breeding nine-banded armadillos (Dasypus novemcinctus) in captivity

Armadillos (Dasypus sp.) are a natural host of a number of protozoal and bacterial pathogens of medical and veterinaty importance. To date , it is the best experimental host of leprosy caused by Mycobacterium leprae and can be naturally infected with this organism. Poor survical-rate of armadillos under conventional housing conditions, however, has proved a major obstacle in breeding D. novemcinctus on captivity. Encouraging results are reported for the breeding and survical of this xenarthran in a walled-off area of forest offering an environment similar to the armadillos' natural habitat. One female raised 2 consecutive litters of 2 and 4 offspring, respectively, to adult age. Increased production is anticipated after preparation of a number of these delimited areas of natural environment for breeding purposes

Development of ultrasonic vocalization responses in genetically heterogeneous National Institute of Health (N:NIH) rats. I. Influence of age, testing experience, and associated factors.

The N:NIH strain of rats was developed by the National Institutes of Health to provide a maximally heterogeneous population as a base for selective breeding (Hansen & Spuhler, 1984). Using the N:NIH strain, this laboratory will selectively breed adult animals that exhibited extremes of high or low ultrasonic vocalization (USV) rates as infants. Because nothing was known about USV in N:NIH rats, we characterized the development of isolation-induced USV in the first generation of this strain born in our laboratory. In a longitudinal/cross-sectional study of pups tested at 3, 10, 15, and 18 days postnatally, N:NIH pups emitted their highest rates of USV at 3-4 days postnatally and calling remained high for 10 days before declining. USV rates were found to be a relatively environmentally stable behavioral trait in that repeated testing did not significantly affect the calling rates of either individuals or litters, and only at 3 days postnatal age did naturally occurring ambient temperature variations (6 degrees C range) significantly affect USV responses. Individual differences in USV responses emerged by 10 days of age that were not simply correlations of body weight or rectal temperature, and pups at that age showed isolation calling rates that were highly predictive of their response levels 5 days later.

Anticonvulsive effect of dapsone (4,4'-diaminodiphenyl sulfone) on amygdala-kindled seizures in rats and cats.

Dapsone (4,4'-diaminodiphenyl sulfone; DDS), an established anti-leprosy drug, showed anticonvulsive effects in the amygdaloid kindling model of epilepsy. Single doses of the drug in rats (6.25-12.5 mg/kg, i.p.) suppressed the kindled seizures in a dose-dependent manner without overt behavioral toxicity. With repeated oral administration in cats, relatively higher initial doses (13-23 mg/kg) were required to obtain seizure suppression, and neurotoxic signs occurred within a few days with serum drug levels of approximately 20 micrograms/ml. Although dapsone showed anticonvulsive effects in both animal species, the effective serum levels overlapped the toxic levels reported in the clinical treatment of leprosy. In the majority of the cats, however, seizure suppression was maintained even after the discontinuation of dapsone with lower serum levels than those observed at the beginning of the seizure suppression. Therefore, dapsone would be useful as an antiepileptic drug only when long-term anticonvulsive efficacy is demonstrated using smaller doses comparable to those used in the treatment of leprosy.

Apomorphine-induced stereotyped biting in the tortoise in relation to dopaminergic mechanisms.

A biting behavior in the Moroccan pond tortoise (Clemmys caspica leprósa) after apomorphine administration is described. The biting behavior was antagonized by the specific anti-dopaminergic drug haloperidol (10 mg/kg) and trifluperazine (15 mg/kg). The behavior was compared to similar behaviors in birds and mammals. The dopamine metabolites, homovanillic acid and 3,4-dihydroxyphenylacetic acid, were measured by a gas chromatographic method in the tortoise brain. From the effects on behavior and the changes in the level of these metabolites upon drug administration it was concluded that the dopamine system in the tortoise is qualitatively similar to that in birds and mammals but less sensitive to blockade.