A distinct role of the queen in coordinated workload and soil distribution in eusocial naked mole-rats

We investigated how group members achieve collective decision-making, by considering individual intrinsic behavioural rules and behavioural mechanisms for maintaining social integration. Using a simulated burrow environment, we investigated the behavioural rules of coordinated workload for soil distribution in a eusocial mammal, the naked mole-rat (Heterocephalus glaber). We tested two predictions regarding a distinct role of the queen, a socially dominant individual in the caste system: the presence of a queen would increase the workload of other caste individuals, and the cues by a queen would affect the soil distribution. In experiment 1, we placed four individuals of various castes from the same colony into an experimental burrow. Workers exhibited the highest frequency of workload compared to other castes. The presence of a queen activated the workload by other individuals. Individuals showed a consistent workload in a particular direction so as to bias the soil distribution. These results suggest that individuals have a consensus on soil distribution and that the queen plays a distinct role. In experiment 2, we placed the odour of a queen in one of four cells and observed its effect on other individuals' workload and soil distribution. Relative to other cells, individuals frequently dug in the queen cell so the amount of soil in the queen cell decreased. These results suggest that queen odour is an important cue in coordinated workload and soil distribution in this species.     

Immunochemistry of the HLA class II molecules isolated from a mouse cell transfected with DQ alpha and beta genes from a DR4 haplotype

Cells from a mouse B lymphoma were transfected by DQ alpha and DQ beta genes derived from a DR4 haplotype. Quantitatively, the resulting expression of human class II molecules was similar to that of human B lymphoblastoid cell lines. Qualitatively, the transformant class II molecules differed from normal class II molecules in their carbohydrate moiety. As for their antigenic specificity, they were shown to carry two determinants previously identified on DQ molecules controlled by DR4 haplotypes, i. e., DQw3 and DCHON. The transformant molecules did not carry a third DR4-associated specificity, DC5 (equivalent to TA10), and must possess a structure allelic to DC5. However, no corresponding alloantigenic specificity was detected by a screening of relevant alloantisera.     

Potentiation by BL191 of differentiation of neuroblastoma cells induced by dibutyryl cAMP and prostaglandin E1

BL191, a newly developed phosphodiesterase inhibitor, markedly potentiated a differentiation of neuroblastoma cell clones (Neuro2a, NS-20Y, and N1E115) induced by dibutyryl cyclic adensoine 3′:5′-monophosphate(dibutyryl cAMP) and prostaglandin E₁ (PGE₁). BL191 (1 mM) inhibited DNA synthesis more strongly when used together with PGE₁ (0.5 μg/ml) and dibutyryl cAMP (0.5 mM) than papaverine (1.6 μg/ml) alone did. The inhibition rates of DNA synthesis were 72.5% for N1E-115, 75.3% for Neuro2a, and 82.5% for NS-20Y. After the treatment with BL191. PGE₁, and dibutyryl cAMP for 48 h all of three cell lines became enlarged and flattened, and extended long processes. The specific activities of choline acetyl transferase (EC 2.3.1.9) of NS-20Y and dopamine β-hydroxylase (EC 1.14.17.1) of N1E-115 increased about 3-fold as compared to the controls. The tumorigenicities of Neuro2a and N1E-115 cells were decreased, but not of NS-20Y. These data suggest the heterogenous responsiveness in neuroblastoma cells to drug treatment.     

Triiodothyronine induces UCP-1 expression and mitochondrial biogenesis in human adipocytes

Uncoupling protein (UCP)-1 expressed in brown adipose tissue plays an important role in thermogenesis. Recent data suggest that brown-like adipocytes in white adipose tissue (WAT) and skeletal muscle play a crucial role in the regulation of body weight. Understanding of the mechanism underlying the increase in UCP-1 expression level in these organs should, therefore, provide an approach to managing obesity. The thyroid hormone (TH) has profound effects on mitochondrial biogenesis and promotes the mRNA expression of UCP in skeletal muscle and brown adipose tissue. However, the action of TH on the induction of brown-like adipocytes in WAT has not been elucidated. Thus we investigate whether TH could regulate UCP-1 expression in WAT using multipotent cells isolated from human adipose tissue. In this study, triiodothyronine (T(3)) treatment induced UCP-1 expression and mitochondrial biogenesis, accompanied by the induction of the CCAAT/enhancer binding protein, peroxisome proliferator-activated receptor-γ coactivator-1α, and nuclear respiratory factor-1 in differentiated human multipotent adipose-derived stem cells. The effects of T(3) on UCP-1 induction were dependent on TH receptor-β. Moreover, T(3) treatment increased oxygen consumption rate. These findings indicate that T(3) is an active modulator, which induces energy utilization in white adipocytes through the regulation of UCP-1 expression and mitochondrial biogenesis. Our findings provide evidence that T(3) serves as a bipotential mediator of mitochondrial biogenesis.     

Combined brain‐derived neurotrophic factor with extinction training alleviate impaired fear extinction in an animal model of post‐traumatic stress disorder

Impaired fear memory extinction (Ext) is one of the hallmark symptoms of post‐traumatic stress disorder (PTSD). However, since the precise mechanism of impaired Ext remains unknown, effective interventions have not yet been established. Recently, hippocampal‐prefrontal brain‐derived neurotrophic factor (BDNF) activity was shown to be crucial for Ext in naïve rats. We therefore examined whether decreased hippocampal‐prefrontal BDNF activity is also involved in the Ext of rats subjected to a single prolonged stress (SPS) as a model of PTSD. BDNF levels were measured by enzyme‐linked immunosorbent assay (ELISA), and phosphorylation of TrkB was measured by immunohistochemistry in the hippocampus and medial prefrontal cortex (mPFC) of SPS rats. We also examined whether BDNF infusion into the ventral mPFC or hippocampus alleviated the impaired Ext of SPS rats in the contextual fear conditioning paradigm. SPS significantly decreased the levels of BDNF in both the hippocampus and mPFC and TrkB phosphorylation in the ventral mPFC. Infusion of BDNF 24 hours after conditioning in the infralimbic cortex (ILC), but not the prelimbic cortex (PLC) nor hippocampus, alleviated the impairment of Ext. Since amelioration of impaired Ext by BDNF infusion did not occur without extinction training, it seems the two interventions must occur consecutively to alleviate impaired Ext. Additionally, BDNF infusion markedly increased TrkB phosphorylation in the ILC of SPS rats. These findings suggest that decreased BDNF signal transduction might be involved in the impaired Ext of SPS rats, and that activation of the BDNF‐TrkB signal might be a novel therapeutic strategy for the impaired Ext by stress.     

Analysis of the NH2-Terminal 83rd Amino Acid of Escherichia coli GyrA in Quinolone-Resistance

Artificial mutations of Gyrase A protein (GyrA) in Escherichia coli by site-directed mutagenesis were generated to analyze quinolone-resistant mechanisms. By genetic analysis of gyrA genes in a gyrA temperature sensitive (Ts) background, exchange of Ser at the NH₂-terminal 83rd position of GyrA to Trp, Leu, Phe, Tyr, Ala, Val, and Ile caused bacterial resistance to the quinolones, while exchange to Gly, Asn, Lys, Arg and Asp did not confer resistance. These results indicate that it is the most important for the 83rd amino acid residue to be hydrophobic in expressing the phenotype of resistance to the quinolones. These findings also suggest that the hydroxyl group of Ser would not play a major role in the quinolone-gyrase interaction and Ser83 would not interact directly with other amino acid residues.     

Genetic characterization of rabies field isolates from Thailand

We sequenced 512 nucleotides in two variable regions of the N gene of 23 rabies isolates from the northeastern part of Thailand by direct sequencing of PCR-amplified products. The sequencing data revealed two new lineages in these rabies isolates. Based on the results of this study together with the findings of our earlier study, the rabies isolates in Thailand were divided into two genogroups, designated as T1 and T2, which were predominantly localized in the northern and northeastern areas, respectively. Each of these two genogroups consisted of four lineages. There was a correlation between these eight lineages and the geographical origins of the isolates. Two lineages belonging to the T2 genogroup from the northeastern area of Thailand were newly identified in this study. The isolates in both genogroups were also prevalent in the central area of Thailand. Each lineage in the T1 and T2 genogroups was found independently in dogs in the upper and lower southern areas of Thailand, respectively. These genetic data and the historical background suggest that rabies viruses belonging to the T2 genogroups were prevalent many years ago in the central and northeastern areas of Thailand and were later transferred to the lower southern parts of Thailand.