Visual, semi-quantitative assessments allow accurate estimates of leafminer population densities: an example comparing image processing and visual evaluation of damage by the horse chestnut leafminer Cameraria ohridella (Lep., Gracillariidae)

Abstract: Qualitative or semi-quantitative visual assessments are most often used for estimating population size of herbivorous insects. The precision of these estimates, however, is often difficult to establish. A 'simulation game' with the horse chestnut leafminer, Cameraria ohridella Deschka & Dimic (Lep., Gracillariidae) shows that visual, semi-quantitative assessments can provide accurate information. Damaged areas of 411 horse chestnut leaves collected in 100 sites were closely related to mine numbers despite some variability in mine and leaf size ( R ² = 0.915; n  = 411; P < 0.001). On the basis of this relationship, two methods of population assessment are compared: (i) digital image processing of leaf damage and (ii) visual assessment using a damage key reflecting the relative infested area on each leaf (0, 0%; 1, 0–2%; 2, 2–5%; 3, 5–10%; 4, 10–25%; 5, 25–50%; 6, 50–75%; 7, 75–100%). Both methods used to estimate damage presented a similar, close relationship to the 'real' numbers of mines ( R ² = 0.858; n  = 777; P < 0.001 for image processing and R ² = 0.905; n  = 777; P < 0.001 for visual assessment). The potential of using visual assessments as an accurate and fast method in situ at the tree scale is discussed.     

Evaluation of PCR assays for quantifying seed-borne infection by Fusarium and Microdochium seedling blight pathogens

Aims:  To evaluate competitive PCR assays for quantifying seed-borne Microdochium and Fusarium seedling blight pathogen DNA and to determine test and year repeatability and sources of variability.
Methods and Results:  Relationships between DNA and plate counts were significant for Fusarium and Microdochium seedling blight pathogens in 152 seed batches from 3 years. Coefficient of determinations, however, differed greatly ( Fusarium ; R ² = 0·25, P  =   0·029, Microdochium ; R ² = 0·73, P  <   0·001). Significant differences between years were observed in the regression slopes for Microdochium . Pathogen DNA quantified in 16 extractions after sampling was highly correlated to results following storage for 1–2 years ( R ² > 0·90). Residual maximum likelihood analysis showed that the least and greatest variance components of the testing procedure were DNA extraction subsampling and PCR assay respectively.
Conclusions:  Amount of pathogen DNA is a useful estimator of seed batch contamination for Microdochium but not Fusarium seedling blight pathogens. Although reproducible over time, improvements to the testing procedure should focus on repeated PCR amplifications to reduce assay variability.
Significance and Impact of the Study:  Replacing plate counts with competitive PCR for determining the severity of seed batch contamination is feasible in areas where Microdochium seedling blight pathogens predominate.     

Interspecific interactions between Bemisia tabaci (Hem., Aleyrodidae) and Liriomyza sativae (Dipt., Agromyzidae)

Abstract:  The study examines interspecific interactions between Bemisia tabaci (Hem., Aleyrodidae) and Liriomyza sativae (Dipt., Agromyzidae) feeding on pumpkins and cucumbers. L. sativae density on control pumpkins and cucumbers peaked 3 and 2 weeks after adults were seen, respectively. Compared with controls, L. sativae densities observed for weeks 3–6 and 2–6 in the B. tabaci -pre-infested plants were significantly lower, respectively ( F _2.00 = 22.66, P < 0.01). The survival of L. sativae larvae transplanted to B. tabaci -pre-infested pumpkins and cucumbers was 16.06%, 10.02% and 13.09%, 9.21%, whereas those transplanted to control plants were 52.20%, 36.06% and 48.25%, 28.22% after 5 and 10 days, respectively ( χ ² = 6.9, d.f. = 1, P < 0.01). Pupation rates of L. sativae feeding on control plants were 20.25% and 16.45%, whereas those feeding on the B. tabaci -pre-infested plants only 4.08% and 4.21%, respectively ( χ ² = 7.0, d.f. = 1, P < 0.01). The length and number of mines of L. sativae on the control pumpkins and cucumbers were 54.05%, 54.10% and 89.06%, 76.22% longer or higher than those on B. tabaci -pre-infested plants, respectively. Leaf positions of L. sativae feeding on the plants were also affected by B. tabaci -pre-infested. These results showed that B. tabaci infestations had a significantly negative effect on L. sativae when they were feeding simultaneously on the same host plant.     

Insecticidal activity influence of destruxins on the pathogenicity of Paecilomyces javanicus against Spodoptera litura

Abstract:  The bioactivities of destruxins (dtx), depsipeptides isolated from Metarhizium anisopliae , against Spodoptera litura were tested in laboratory. For contacting toxicities, dtx-E was more effective than dtx-A and dtx-B. The LC₅₀s values of dtx-A, B and E were 197.98, 292.00 and 113.99 mg/l at 48 h after treatment, while the LT₅₀s were 42.65, 59.45 and 23.68 h at 300 mg/l. In the experiment of antifeedant activity, dtx-A, dtx-B and dtx-E at five concentrations (200, 100, 50, 25 and 12.5 mg/l) were bioassayed. Destruxins in a dose-dependent manner gave an apparent antifeedant activity. Generally, dtx-A, over dtx-B and dtx-E had the significant (P < 0.05) larger choice and no-choice antifeedant indexes (CAIs and NCAIs). At the concentration of 200 mg/l, the CAIs or NCAIs of dtx-A, dtx-B and dtx-E were 96.78, 84.93 and 85.90 or 89.75, 62.42 and 72.28 respectively. Furthermore, the synergistic activity of crude destruxin (CD) for pathogenicity of Paecilomyces javanicus strain Pj01 was detected. The LC₅₀s values of single Pj01 and the mixtures of Pj01 plus CD at 100 or 200 mg/l (Pj01-CD100 or Pj01-CD200) were respectively 474.63 × 10⁵, and 197.45 × 10⁵ or 113.11 × 10⁵ spores/ml at the fifth day after treated. Meanwhile, Pj01, Pj01-CD100 and Pj01-CD200 gave the LT₅₀s values of 6.99 day, 5.49 day and 4.21 day at 100 × 10⁵ spores/ml. Clearly, dtx decreased the values of LC₅₀ and LT₅₀ of the strain Pj01.     

Genetic diversity and population structure of Pichia guilliermondii over 400 generations of experimental microevolution

An in vitro evolution model was used to study changes in the genetic diversity of 24 strains of Pichia guilliermondii isolated from the midgut of bark beetles of the genus Dendroctonus . The genetic diversity of P. guilliermondii strains over 400 generations was analysed using multilocus enzyme electrophoresis (MLEE) and random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) markers. Resemblance relationships among strains were observed by cluster analysis. From the MLEE and RAPD markers, it was shown that the effective number of alleles, polymorphism and expected heterozygosity varied over the generations. The average heterozygosity among generations was statistically significant. Both the genetic diversity and the average heterozygosity were statistically significant among generations. The reduction in the population size from 10⁹ to 10⁵ yeast mL⁻¹ associated with each transfer in P. guilliermondii strains and the clonal population structure observed along 400 generations suggest that genetic diversity changes and the observed replacement of genotypes are a consequence of a genetic drift process and not of the reproductive mode.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 475–486.     

Ontogeny and stability of separation and threat-induced defensive behaviors in rhesus monkeys during the first year of life

Twenty-six rhesus monkeys were tested repeatedly at 4, 8, and 12 months of age to characterize the expression and development of their defensive responses induced by separation from their mothers and exposure to a potential threat. Results demonstrated that by 4 months of age infant monkeys engaged in adult-like context-dependent responses and adaptively regulated these responses in relation to the changing context. When separated from their mothers and alone, infants at 4 months of age were active and emitted frequent coo vocalizations. However, when exposed to the profile of a human face, infants responded by becoming behaviorally inhibited and freezing. At 8 months of age, a dramatic reduction in infants' separation-induced coos was observed, whereas their duration of threat-induced freezing remained unchanged. At 12 months of age, a further decrease in cooing occurred, while freezing duration was maintained. No sex differences were found in the expression of these behaviors or their developmental patterns. Individual differences in separation-induced cooing and threat-induced freezing were apparent and remained stable over the three ages studied. However, within animals no relation was found between individual differences in cooing and freezing. These data demonstrate important differences in the developmental patterns for the expression of cooing and freezing over the first year of life. Marked individual differences in separation-induced cooing and threat-induced freezing were apparent and remained stable from 4–12 months of age. The data support the hypothesis that these different defensive responses reflect different adaptive responses that likely have different underlying mechanisms. The similarities between these defensive responses in rhesus monkeys and humans suggests that understanding the factors that promote the development of individual differences in monkeys will illuminate important factors that promote individual differences in humans. Am. J. Primatol. 44:125–135, 1998. ©1998 Wiley-Liss, Inc.     

Impact of temperature on food intake and growth in juvenile burbot

The effect of temperature on food consumption, food conversion and somatic growth was investigated with juvenile burbot Lota lota (age 0 years). Juvenile burbot showed a significant dome shaped relationship between relative daily food consumption ( C _R) and temperature ( T ) with C _R = − 0·00044 T ² + 0·01583 T  − 0·06010; ( n  = 90, r ² = 0·61). Maximum C _R was at 17·9° C (95% CL 17·2–18·6° C). The temperature related instantaneous growth rate ( G ) also followed a dome shaped function with G  = − 0·000063 T ² + 0·002010 T  − 0·007462; ( n  = 95, r ² = 0·57), with maximum growth rate at 16·0° C (95% CL 15·3–16·6° C). A significant linear relationship was found between the water temperature and the conversion coefficient ( C _C) with C _C = − 1·63 T  + 59·04; ( n  = 80, r ² = 0·74). The results indicate that juvenile burbot in large lakes benefit from higher water temperatures in the littoral zone, by increased food uptake and growth, especially during the warm summer months. Because profundal water temperatures do not reflect the optimal temperature for food consumption in large burbot, temperature is unlikely to be the main proximate factor for the obligate littoral‐profundal migration of juvenile burbot observed in many lake populations.     

Ecosystem productivity can be predicted from potential relative growth rate and species abundance

We show that ecosystem-specific aboveground net primary productivity (SANPP, g g⁻¹ day⁻¹, productivity on a per gram basis) can be predicted from species-level measures of potential relative growth rate (RGR_max), but only if RGR_max is weighted according to the species' relative abundance. This is in agreement with Grime's mass-ratio hypothesis. Productivity was measured in 12 sites in a French Mediterranean post-agricultural succession, while RGR_max was measured on 26 of the most abundant species from this successional sere, grown hydroponically. RGR_max was only weakly correlated ( r ² = 0.12, P  < 0.05) with field age when species abundance was not considered, but the two variables were strongly correlated ( r ² = 0.81, P  < 0.001) when the relative abundance of species in each field was taken into account. SANPP also decreased significantly with field age. This resulted in a tight relationship ( r ² = 0.77, P  < 0.001) between productivity and RGR_max weighted according to species relative biomass contribution. Our study shows that scaling-up from the potential properties of individual species is possible, and that information on potential and realized species traits can be integrated to predict ecosystem functioning.     

Aboveground biomass estimation of the shrubs, Echiochilon fruticosum (Desf.) and Helianthemum kahiricum (Del.) in the arid zone rangelands of Tunisia

The knowledge of the plant biomass is very important for the assessment of the rangeland productivity. It could help to select the appropriate species for the improvement of natural ecosystems (rehabilitation, restoration and seedling). By examining different correlations between the biomass production and the volume parameters of two North African shrub species of high range value ( Echiochilon fruticosum Desf. and Helianthemum kahiricum Del.), we aimed to establish the appropriate regression models, which could be useful for the prediction of the productivity of these species. The data showed a significant relationship between the total biomass (TB) production and the mean diameter (MD) of the studied species ( R ² = 0.65 for Echiochilon and R ² = 0.75 for Helianthemum ). Likewise, annual fresh production (leaves and current-year shoots) was well correlated with MD of Helianthemum ( R ² = 0.82). However, the correlation between these two parameters was relatively low for Echiochilon ( R ² = 0.42).     

Efficacy of Beauveria bassiana (Bals.) Vuill. against the spruce bark beetle, Ips typographus L., in the laboratory under various conditions

Abstract:  In laboratory bioassays, the efficacy of the entomopathogenic fungus Beauveria bassiana against the spruce bark beetle, Ips typographus , was tested under various conditions. Four of the tested isolates and the commercial product Boverol^® caused 99–100% mortality when tested at a concentration of 1.0 × 10⁷ conidia/ml at 25°C. Using B. bassiana isolate 138 at a concentration of 1.0 × 10⁶, the median survival time (MST) was 6.1 d and significantly longer compared with the MST of 4.2 and 4.0 d at 1.0 × 10⁷ and 1.0 × 10⁸ conidia/ml, respectively. In the next experiment, the beetles were maintained on spruce bark, filter paper or artificial diet during the bioassay with Boverol^®, and significant differences in the MST of 3.6, 2.5 and 5.3 d, respectively, were noticed. The experiment with Boverol^® at different temperatures showed that the beetles lived significantly longer at 15°C (MST 8.7 d) than at 20, 25, 30 and 35°C. At 25°C, the beetles died most rapidly (MST 3.5 d). At different relative humidities (RH) of 40, 70 and 100%, nearly all beetles were dead after treatment with a suspension of Boverol^® at 1.0 × 10⁷ conidia/ml. At 40% RH, 49% of the untreated beetles died after 7 d. The best effects were achieved with the following bioassay: beetles were fed for three days on artificial diet, then dipped into a solution of 1.0 × 10⁷ conidia/ml and transferred on a piece of spruce bark in Petri dishes at 25°C and 70% RH.     

Automated concentration and recovery of micro-organisms from drinking water using dead-end ultrafiltration

Aims:  Concentration of pathogens diluted in large volumes of water is necessary for their detection. An automated concentration system placed online in drinking water distribution systems would facilitate detection and mitigate the risk to public health.
Methods and Results:  A prototype concentrator based on dead-end hollow fibre ultrafiltration was used to concentrate Bacillus atrophaeus spores directly from tap water. Backflush was used to recover accumulated particulates for analysis. In field tests conducted on a water utility distribution system, 3·2 × 10⁴–1·4 × 10⁶ CFU ml⁻¹ (6·1 × 10⁶–3·0 × 10⁸ CFU) were recovered from the filter when 2·9 × 10⁷–1·0 × 10⁹ CFU were spiked into the system. Per cent recovery ranged from 21% to 68% for flow volumes of 15–21 l. Tests using spore influent levels <10 CFU l⁻¹ (spike < 1000 CFU) yielded 23–40% recovery for volumes >100 l.
Conclusions:  B. atrophaeus spores at levels <10 CFU l⁻¹ were concentrated directly from tap water using an automated dead-end hollow-fibre ultrafiltration system.
Significance and Impact of the Study:  The prototype concentrator represents a critical step towards an autonomous system that could be installed in drinking water distribution lines or other critical water lines to facilitate monitoring. Recovered samples can be analysed using standard or rapid biosensor methods.     

Association analysis of the catechol-o-methyltransferase (COMT), serotonin transporter (5-HTT) and serotonin 2A receptor (5HT2A) gene polymorphisms with obsessive-compulsive disorder

Family and twin studies have supported a strong genetic factor in the etiology of obsessive-compulsive disorder (OCD), although the precise mechanism of inheritance is unclear. Clinical and pharmacological studies have implicated the serotonergic and dopaminergic systems in disease pathogenesis. In this cross-sectional study, we have examined the allelic and genotypic frequencies of a Val-158-Met substitution in the COMT gene, a 44-base pair (bp) length variation in the regulatory region of the serotonin transporter gene ( 5-HTTLPR ) and the T102C and C516T variants in the serotonin receptor type 2A ( 5HT2A ) gene in 79 OCD patients and 202 control subjects. There were no observed differences in the frequencies of allele and genotype between patients and control groups for the COMT , the 5HTTLPR and the T102C 5HT2A gene polymorphisms. In contrast, a statistically significant difference between OCD patients and controls was observed on the genotypic distribution (χ² = 16.7, 2df, P  = 0.0002) and on the allelic frequencies (χ² = 15.8, 1df, P  = 0.00007) for the C516T 5HT2A gene polymorphism. The results suggest that the C516T variant of the 5HT2A gene may be one of the genetic risk factors for OCD in our sample. However, further studies using larger samples and family based methods are recommended to confirm these findings.     

Virulence of luminescent and non-luminescent isogenic vibrios towards gnotobiotic Artemia franciscana larvae and specific pathogen-free Litopenaeus vannamei shrimp

Aims:  This study was conducted to test the virulence of luminescent (L) and non-luminescent (NL) isogenic strains of Vibrio campbellii LMG21363, Vibrio harveyi BB120 (wild type) and quorum-sensing mutant strains derived from the wild type such as Vibrio harveyi BB152, BB170, MM30 and BB886.
Methods and Results:  The NL strains could be obtained by culturing rifampicin-resistant luminescent strains in the dark under static condition. The virulence of the L and NL strains was tested in gnotobiotic Artemia franciscana larvae challenged with 10⁴ CFU ml⁻¹ of bacteria. All luminescent isogenic tested strains showed higher virulence compared to the NL strains. The virulence of L and NL V. campbellii and V. harveyi BB120 was also tested in specific pathogen-free juvenile shrimp upon intramuscular injection with 10⁶ CFU of bacteria. In contrast with Artemia , there was no significant difference in mortality between the groups challenged with L and NL strains ( P  > 0·05). The non-luminescent strains were not able to revert back to the luminescent state and quorum sensing did not influence this phenotypic shift.
Conclusions:  Luminescent Vibrio strains can switch to a non-luminescent state by culturing them in static conditions. The NL strains become less virulent as verified in Artemia .
Significance and Impact of the Study:  The luminescent state of Vibrio cells in a culture needs to be verified in order to assure maintenance of virulence.     

Growth performance, mortality and carotenoid pigmentation of fry offspring as affected by dietary supplementation of astaxanthin to female rainbow trout (Oncorhynchus mykiss) broodstock

Growth performance, mortality and carotenoid pigmentation were studied in triplicate groups each with 1000 swim-up larvae of rainbow trout ( Oncorhynchus mykiss ), derived from five groups of female broodstock fed diets with 0.07, 12.5, 33.3, 65.1 or 92.9 mg astaxanthin kg⁻¹, respectively. The first feeding fry (initial weight range from 113 to 148 mg) were fed a diet not supplemented with carotenoids in an experiment lasting 45 days. Fry were initially sampled for astaxanthin content and initial weight, and in subsequent 15-day intervals to determine weights, condition factors (CF), specific growth rates (SGR) and thermal growth coefficients (TGC). Total carotenoid concentration of the larvae was highly linearly correlated to that of the eggs ( r ² = 0.97, P = 0.002). About 59–67% of fry carotenoids consisted of esterified astaxanthin, and on average 39.7% of the egg carotenoids were recovered in the fry. Overall (0–45 days) SGRs and TGCs were significantly higher (P < 0.05) in the offspring of the four groups of females fed supplemented diets (12.5–92.9 mg astaxanthin kg⁻¹) than in offspring of females fed the non-supplemented diet. TGCs (0–45 days) within groups derived from broodstock supplemented with astaxanthin were similar (P > 0.05), but higher than in the group derived from females fed the diet not supplemented with astaxanthin (P < 0.05). Mortality (average 0.76%) was not significantly affected by treatment. The study indicates that dietary supplement of astaxanthin (>12.5 mg kg⁻¹) to maternal broodstock diets improves offspring SGR and TGC with up to 33 and 38%, respectively.     

Microbial colonization of an in vitro model of a tissue engineered human skin equivalent – a novel approach

This was a preliminary investigation to define the conditions of colonization of a human skin equivalent (SE) model with cutaneous microorganisms. SEs of 24 mm diameter were constructed with a dermal matrix of fibrin containing fibroblasts and a stratified epidermis. Microbial colonization of the SEs was carried out in a dry environment, comparable to ' in vivo ' skin, using a blotting technique to remove inoculation fluid. The microbial communities were sampled by scrub washing and viable cells enumerated on selective growth medium. Staphylococcus epidermidis , Propionibacterium acnes and Malassezia furfur (human skin commensals) and Staphylococcus aureus (transient pathogen) were colonized at inoculum densities of 10²–10⁶ CFU SE⁻¹ on the surface of replicate SEs. Growth of all species was supported for upto 72–120 h, with recovery densities of between 10⁴–10⁹ CFU SE⁻¹. A novel, real-time growth monitoring method was also developed, using S. aureus containing a lux cassette. Light output increased from 20 to 95 h, and colonization increased from 10² to 10⁸ CFU SE⁻¹, as confirmed by conventional recovery. Thus, the SE model has potential to investigate interactions between resident and transient microbial communities with themselves and their habitat, and for testing treatments to control pathogen colonization of human skin.     

Maturing dynamics of surface microflora in Fontina PDO cheese studied by culture-dependent and -independent methods

Aims:  To study the evolution of rind microbial communities in Fontina PDO cheese.
Methods and Results:  Four batches were examined for their surface microflora during ripening, carried out in two different maturing caves, at Ollomont and Pré-Saint-Didier, Aosta Valley region, Northwest of Italy. Culture-dependent methodologies were combined with culture-independent analysis (PCR-DGGE). Yeasts were found to increase from 10³ to 10⁶ CFU cm⁻² in 28 days, with consequent rise of surface pH, which allowed the growth of salt-tolerant bacteria, in particular coryneforms which reached 10⁹ CFU cm⁻² at the end of 3 months. Coagulase-negative cocci and lactic acid bacteria reached 10⁷ CFU cm⁻² in the same period. Debaryomyces hansenii and Candida sake were the species more constantly present throughout the whole maturing process. As early as after 1 day since manufacture, Lactococcus lactis subsp. lactis and Streptococcus thermophilus were detected on cheese rinds. Arthrobacter nicotianae , Brevibacterium casei and Corynebacterium glutamicum were found after 7–28 days .
Conclusions:  According to cluster analysis of DGGE profiles, the maturing environment seemed to influence the dynamics of microbial groups on Fontina surfaces.
Significance and Impact of the Study:  These results represent a first picture of micro-organisms colonizing Fontina PDO rinds. Further studies are in progress to better understand the origin of this surface microflora and to formulate surface starters.     

Relationships between the lucerne flea, Sminthurus viridis (L.) (Collembola: Sminthuridae), and damage to lucerne

Abstract The effect of lucerne flea, Sminthurus viridis , on plant growth (stem length and leaf number) and damage (percentage of leaves damaged and the percentage reduction in leaf area in the top, mid and lower thirds of stems) was considered at 2-weekly intervals in three consecutive lucerne growth cycles, each with a different mode of attack. The data were analysed to progressively determine relationships leading to a proposal for plant-based thresholds for lucerne flea control. Lucerne flea affected each factor measured, with damage considered more appropriate for making control decisions than plant growth. Damage increased from the base of plants upwards and its effect on yield was carried over into subsequent growth cycles. Damage was significantly related to lucerne flea numbers ( P  < 0.001) in two growth cycles and was higher when large nymphs or adults were dominant in one of these cycles. Yield was closely and best related to the percentage of the total number of leaves damaged ( R ² = 81.3%). The percentage of leaves damaged was also related to loss of final yield estimated at 2 ( R ² = 81.3%), 4 ( R ² = 78.9%) and 6 ( R ² = 66.6%) weeks into the first growth cycle only. Direct damage in the other two cycles did not result in yield loss. The percentage of leaves damaged (± confidence intervals) equating to 5% increments in yield loss were estimated at 2, 4 and 6 weeks into the first growth cycle. These are proposed as damage or treatment thresholds for testing.     

Serotonin Transporter Genotype Modulates Social Reward and Punishment in Rhesus Macaques

Background

Serotonin signaling influences social behavior in both human and nonhuman primates. In humans, variation upstream of the promoter region of the serotonin transporter gene (5-HTTLPR) has recently been shown to influence both behavioral measures of social anxiety and amygdala response to social threats. Here we show that length polymorphisms in 5-HTTLPR predict social reward and punishment in rhesus macaques, a species in which 5-HTTLPR variation is analogous to that of humans.

Methodology/Principal Findings

In contrast to monkeys with two copies of the long allele (L/L), monkeys with one copy of the short allele of this gene (S/L) spent less time gazing at face than non-face images, less time looking in the eye region of faces, and had larger pupil diameters when gazing at photos of a high versus low status male macaques. Moreover, in a novel primed gambling task, presentation of photos of high status male macaques promoted risk-aversion in S/L monkeys but promoted risk-seeking in L/L monkeys. Finally, as measured by a “pay-per-view” task, S/L monkeys required juice payment to view photos of high status males, whereas L/L monkeys sacrificed fluid to see the same photos.

Conclusions/Significance

These data indicate that genetic variation in serotonin function contributes to social reward and punishment in rhesus macaques, and thus shapes social behavior in humans and rhesus macaques alike.     

Altered conditioned fear behavior in glutamate decarboxylase 65 null mutant mice

We investigated the involvement of the 65 kDa isoform of glutamic acid decarboxylase (GAD65) and GAD65-mediated γ-aminobutyric acid (GABA) synthesis in the formation and expression of Pavlovian fear memory. To this end, behavioral, endocrine and autonomic parameters were examined during conditioned fear retrieval of mice with targeted ablation of the GAD65 gene (GAD65^–/– mice). These mutant mice were found to display specific fear behavior (freezing, escape), as well as autonomic (increased defecation) and endocrine activation (increased plasma corticosterone) during fear memory retrieval. However, freezing was reduced and flight and escape behavior were increased in GAD65^–/– mice compared to their wild type and heterozygous littermates, while corticosterone levels and defecation rates did not differ between genotypes. Active defensive behavior of GAD65^–/– mice was observed during both auditory cued and contextual retrieval of fear memory, as well as immediately after conditioning. These data indicate a selectively altered behavioral fear response in GAD65^–/– mice, most likely due to deficits in threat estimation or the elicitation of appropriate conditioned fear behavior, and suggest that GAD65 is a genetic determinant of conditioned fear behavior. GAD65^–/– mice provide a valuable tool to further dissect the GABAergic mechanisms involved in fear and anxiety and to model GABA-related neurological and psychiatric disorders.     

Effect of Lactobacillus gasseri BNR17 on blood glucose levels and body weight in a mouse model of type 2 diabetes

Aims:  To investigate the effect of Lactobacillus gasseri BNR17 isolated from human breast milk on blood glucose and body weight in type 2 diabetic animals.
Methods and results:  db/db mice were divided into one control group and five sample groups; the sample groups received BNR17 (10⁷, 10⁸, 10⁹ and 10¹⁰ CFU) or rosiglitazone (8 mg kg⁻¹) orally twice a day for 12 weeks. BNR17 groups had a dose-dependent reduction in food, water intake and amount of excrement. Body weight loss was not seen in the BNR17 groups. Fasting and postprandial 2 h blood glucose levels were significantly lower in the BNR17 (10¹⁰ CFU) group compared with the control group. HbA1c decreased in the BNR17 group, although it was not statistically significant. During the oral glucose tolerance test, the BNR17 groups exhibited dose-dependent improvement in glucose sensitivity.
Conclusions:  Lactobacillus gasseri BNR17 has a suppressing effect on blood glucose levels and improved diabetic symptoms in db/db mice.
Significance and Impact of the Study:  Blood glucose-lowering lactic acid bacteria are expected to be useful as a therapeutic for treating type 2 diabetes in humans.