Genetic Structure of Wild Bonobo Populations: Diversity of Mitochondrial DNA and Geographical Distribution

Bonobos (Pan paniscus) inhabit regions south of the Congo River including all areas between its southerly tributaries. To investigate the genetic diversity and evolutionary relationship among bonobo populations, we sequenced mitochondrial DNA from 376 fecal samples collected in seven study populations located within the eastern and western limits of the species’ range. In 136 effective samples from different individuals (range: 7–37 per population), we distinguished 54 haplotypes in six clades (A1, A2, B1, B2, C, D), which included a newly identified clade (D). MtDNA haplotypes were regionally clustered; 83 percent of haplotypes were locality-specific. The distribution of haplotypes across populations and the genetic diversity within populations thus showed highly geographical patterns. Using population distance measures, seven populations were categorized in three clusters: the east, central, and west cohorts. Although further elucidation of historical changes in the geological setting is required, the geographical patterns of genetic diversity seem to be shaped by paleoenvironmental changes during the Pleistocene. The present day riverine barriers appeared to have a weak effect on gene flow among populations, except for the Lomami River, which separates the TL2 population from the others. The central cohort preserves a high genetic diversity, and two unique clades of haplotypes were found in the Wamba/Iyondji populations in the central cohort and in the TL2 population in the eastern cohort respectively. This knowledge may contribute to the planning of bonobo conservation.     

LORETA Current Source Density for Duration Mismatch Negativity and Neuropsychological Assessment in Early Schizophrenia

Introduction

Patients with schizophrenia elicit cognitive decline from the early phase of the illness. Mismatch negativity (MMN) has been shown to be associated with cognitive function. We investigated the current source density of duration mismatch negativity (dMMN), by using low-resolution brain electromagnetic tomography (LORETA), and neuropsychological performance in subjects with early schizophrenia.

Methods

Data were obtained from 20 patients meeting DSM-IV criteria for schizophrenia or schizophreniform disorder, and 20 healthy control (HC) subjects. An auditory odd-ball paradigm was used to measure dMMN. Neuropsychological performance was evaluated by the brief assessment of cognition in schizophrenia Japanese version (BACS-J).

Results

Patients showed smaller dMMN amplitudes than those in the HC subjects. LORETA current density for dMMN was significantly lower in patients compared to HC subjects, especially in the temporal lobes. dMMN current density in the frontal lobe was positively correlated with working memory performance in patients.

Conclusions

This is the first study to identify brain regions showing smaller dMMN current density in early schizophrenia. Further, poor working memory was associated with decreased dMMN current density in patients. These results are likely to help understand the neural basis for cognitive impairment of schizophrenia.     

Cold shock proteins improve E. coli cell-free synthesis in terms of soluble yields of aggregation-prone proteins

Protein folding is usually slowed-down at low temperatures, and thus low-temperature expression is an effective strategy to improve the soluble yield of aggregation-prone proteins. In this study, we investigated the effects of a variety of cold shock proteins and domains (Csps) on an Escherichia coli cell extract-based cell-free protein synthesis system (CF). Most of the 12 Csps that were successfully prepared dramatically improved the protein yields, by factors of more than 5 at 16°C and 2 at 23°C, to levels comparable to those obtained at 30°C. Their stimulatory effects were complementary to each other, while CspD and CspH were inhibitory. The Csps’ effects correlated well with their Pfam CSD family scores (PF00313.22). All of the investigated Csps, except CspH, similarly possessed RNA binding and chaperon activities and increased the messenger RNA amount irrespective of their effect, suggesting that the proper balance between these activities was required for the enhancement. Unexpectedly, the 5′-untranslated region of cspA was less effective as the leader sequence. Our results demonstrated that the use of the Csps presented in this study will provide a simple and highly effective strategy for the CF, to improve the soluble yields of aggregation-prone proteins.     

Single Quantum Dot Tracking Reveals that an Individual Multivalent HIV-1 Tat Protein Transduction Domain Can Activate Machinery for Lateral Transport and Endocytosis

The mechanisms underlying the cellular entry of the HIV-1 Tat protein transduction domain (TatP) and the molecular information necessary to improve the transduction efficiency of TatP remain unclear due to the technical limitations for direct visualization of TatP''s behavior in cells. Using confocal microscopy, total internal reflection fluorescence microscopy, and four-dimensional microscopy, we developed a single-molecule tracking assay for TatP labeled with quantum dots (QDs) to examine the kinetics of TatP initially and immediately before, at the beginning of, and immediately after entry into living cells. We report that even when the number of multivalent TatP (mTatP)-QDs bound to a cell was low, each single mTatP-QD first locally induced the cell''s lateral transport machinery to move the mTatP-QD toward the center of the cell body upon cross-linking of heparan sulfate proteoglycans. The centripetal and lateral movements were linked to the integrity and flow of actomyosin and microtubules. Individual mTatP underwent lipid raft-mediated temporal confinement, followed by complete immobilization, which ultimately led to endocytotic internalization. However, bivalent TatP did not sufficiently promote either cell surface movement or internalization. Together, these findings provide clues regarding the mechanisms of TatP cell entry and indicate that increasing the valence of TatP on nanoparticles allows them to behave as cargo delivery nanomachines.     

The SNP in the promoter region of the bovine ELOVL5 gene influences economic traits including subcutaneous fat thickness

Genetic analyses have contributed to improvements of economically important traits derived from adipose tissue such as fatty acid composition in beef. Elongation of very long chain fatty acids (ELOVL) genes encode for the enzymes that play an important role in elongation of long-chain fatty acids. In this study, we aimed to discover genetic polymorphisms of ELOVL gene family in cattle populations to develop genetic markers. As a result, five synonymous mutations were detected in the coding regions of the ELOVL1, ELOVL2, ELOVL3 and ELOVL5 genes. In addition, six mutations were identified in promoter region of the ELOVL5. Two of five mutations in the promoter region of ELOVL5 were expected to alter the ELOVL5 expression and influence the economic traits, because of the high synteny of the region which was essential for activation of Elovl5 in mouse. Therefore, we performed association analysis between the genotypes and traits and our result revealed that T allele of g.-110T>C in ELOVL5 gene promoter indicated significantly thinner subcutaneous fat thickness (TT, 2.39 cm; CT, 2.35 cm) than that of C allele (CC, 2.68 cm) in a Japanese Black population. Our results suggest that the g.-110T>C is a useful genetic marker for the breeding in beef cattle.     

Genotypic characteristics of a Mycobacterium sp. isolated from yellowtail Seriola quinqueradiata and striped jack Pseudocaranx dentex in Japan

In Japan, a Mycobacterium marinum‐like mycobacterium was isolated from the yellowtail, Seriola quinqueradiata. The species was identified as M. marinum by a commercial mycobacterial DNA‐DNA hybridization kit. Nevertheless, PCR restriction analysis of the DNA of its RNA polymerase β‐subunit gene definitively showed that this Mycobacterium sp. was M. ulcerans. PCR analysis revealed the genotypic characteristics of M. ulcerans in the Mycobacterium sp., only the mup053 gene sequence being absent, as has been found previously in other piscine mycobacteria such as M. marinum strains DL240490 and DL045 and M. pseudoshottsii. With one exception, this Mycobacterium sp. and M. pseudoshottsii had identical 16S rRNA gene sequences, which is also probably true of M. marinum strains DL240490 and DL045. Similarly, according to comparisons of the 16S rRNA gene, ITS region, and hsp65 gene sequences, this Mycobacterium sp. is more closely related to M. pseudoshottsii than to M. ulcerans or M. marinum. A PCR product of approximately 2000 bp was amplified from region of difference 9 in the Mycobacterium sp. The nucleotide sequence revealed insertion of IS2404, the sequence of which is 1366 bp long. The novel single nucleotide polymorphisms identified in this region distinguished this Mycobacterium sp. from M. marinum strain DL240490 and M. pseudoshottsii. The present findings raise the possibility that these species have a common ancestor. Further studies are required to improve our understanding of the relationship between their geographical origin and genetic diversity.     

Elasticity and physico-chemical properties during drinking water biofilm formation

Atomic force microscope techniques and multi-staining fluorescence microscopy were employed to study the steps in drinking water biofilm formation. During the formation of a conditioning layer, surface hydrophobic forces increased and the range of characteristic hydrophobic forces diversified with time, becoming progressively complex in macromolecular composition, which in return triggered irreversible cellular adhesion. AFM visualization of 1 to 8 week drinking water biofilms showed a spatially discontinuous and heterogeneous distribution comprising an extensive network of filamentous fungi in which biofilm aggregates were embedded. The elastic modulus of 40-day-old biofilms ranged from 200 to 9000 kPa, and the biofilm deposits with a height >0.5 μm had an elastic modulus <600 kPa, suggesting that the drinking water biofilms were composed of a soft top layer and a basal layer with significantly higher elastic modulus values falling in the range of fungal elasticity.     

Unique features of the motility and structures in the flagellate polar region of Campylobacter jejuni and other species: an electron microscopic study

Similarly to Helicobacter pylori but unlike Vibrio cholerae O1/O139, Campylobacter jejuni is non‐motile at 20°C but highly motile at ≥37°C. The bacterium C. jejuni has one of the highest swimming speeds reported (>100 μm/s), especially at 42°C. Straight and spiral bacterial shapes share the same motility. C. jejuni has a unique structure in the flagellate polar region, which is characterized by a cup‐like structure (beneath the inner membrane), a funnel shape (opening onto the polar surface) and less dense space (cytoplasm). Other Campylobacter species (coli, fetus, and lari) have similar motility and flagellate polar structures, albeit with slight differences. This is especially true for Campylobacter fetus, which has a flagellum only at one pole and a cup‐like structure composed of two membranes.     

Roles of transient receptor potential canonical (TRPC) channels and reverse-mode Na/Ca exchanger on cell proliferation in human cardiac fibroblasts: Effects of transforming growth factor β1

Expression of transient receptor potential canonical channels (TRPC) and the effects of transforming growth factor-β1 (TGF-β1) on Ca²⁺ signals and fibroblast proliferation were investigated in human cardiac fibroblasts. The conventional and quantitative real-time RT-PCR, western blot, immunocytochemical analysis, and intracellular Ca²⁺ concentration [Ca²⁺]_i measurement were applied. Cell proliferation and cell cycle progression were assessed using MTT assays and fluorescence activated cell sorting. Human cardiac fibroblasts have the expression of TRPC1,3,4,6 mRNA and proteins. 1-oleoyl-2-acetyl-sn-glycerol (OAG) and thapsigargin induced extracellular Ca²⁺-mediated [Ca²⁺]_i rise. siRNA for knock down of TRPC6 reduced OAG-induced Ca²⁺ entry. Hyperforin as well as angiotensin II (Ang II) induced Ca²⁺ entry. KB-R7943, a reverse-mode Na⁺/Ca²⁺ exchanger (NCX) inhibitor, and/or replacement of Na⁺ with NMDG⁺ inhibited thapsigargin-, OAG- and Ang II-induced Ca²⁺ entry. Treatment with TGF-β1 increased thapsigargin-, OAG- and Ang II-induced Ca²⁺ entry with an enhancement of TRPC1,6 protein expression, suppressed by KB-R7943. TGF-β1 and AngII promoted cell cycle progression from G0/G1 to S/G2/M and cell proliferation. A decrease of the extracellular Ca²⁺ and KB-R7943 suppressed it. Human cardiac fibroblasts contain several TRPC-mediated Ca²⁺ influx pathways, which activate the reverse-mode NCX. TGF-β1 enhances the Ca²⁺ influx pathways requiring Ca²⁺ signals for its effect on fibroblast proliferation.     

Variable alteration of regional tissue oxygen pressure in rat hippocampus by acute swimming exercise

One of the events in the brain is an increasing cerebral blood flow during exercise. The tissue oxygen level may be increased because blood flow correlates with tissue oxygen level. However, it is little known whether the tissue oxygen pressure in hippocampal region (Hip-pO₂) will be affected by exercise.