Population dynamics of five anopheles species of the Hyrcanus group in northern Gyeonggi-do, Korea

To investigate the population densities of potential malaria vectors, Anopheles species were collected by light traps in malaria endemic areas, Paju and Gimpo, Gyeonggi-do of Korea. Five Anopheles Hyrcanus sibling species (An. sinensis, An. pullus, An. lesteri, An. kleini, and An. belenrae) were identified by PCR. The predominant species, An. pullus was collected during the late spring and mid-summer, while higher population consists of An. sinensis were collected from late summer to early autumn. These 2 species accounted for 92.1% of all Anopheles mosquitoes collected, while the other 3 species accounted for 7.9%. Taking into account of these population densities, late seasonal prevalence, and long-term incubation period (9-13 months) of the Korean Plasmodium vivax strain, An. sinensis s.s is thought to play an important role in the transmission of vivax malaria in the study areas.     

A 26,000-year integrated record of marine and terrestrial environmental change off Gabon, west equatorial Africa

Dinoflagellate cysts, pollen and charred cuticle fragments from two sediment cores (giant piston Calypso core MD03-2708 and giant gravity Casq core MD03-2708CQ) collected off the Ogooué River mouth, Gabon (01°10.33′S-08°19.01′E, 920 m water depth) have been analysed to identify the direction and timing of marine-terrestrial environmental changes over western equatorial Africa during the last 26,000 yr. Changes in the proxy records indicate that both terrestrial and oceanic domains off Gabon were impacted synchronously by significant climate changes during the last glacial-interglacial transition and Holocene. Leading into, and during, the Last Glacial Maximum (LGM), heterotrophic dinoflagellate cysts and Ca X-ray fluorescence intensity suggest nutrient enrichment off the river mouth, while pollen records indicate expansions of open forest, savannah woodland, and the Afromontane forest in the catchment area. From the deglaciation to mid-Holocene, however, a marked decrease in Brigantedinium spp. as well as in Poaceae, Cyperaceae and Podocarpus pollen reflects a reduction in nutrient supply to the coastal ocean in parallel with a reduction in grassland, herbaceous communities and Afromontane forest within the catchment. A sharp decline or even disappearance of heterotrophic species during this period is almost contemporaneous with an appearance of Operculodinium aguinawense, reflecting enhanced river influence in the study area. A marked increase of Rhizophora (mangrove) pollen during this transition also indicates eustatic sea-level rise after the LGM which forced a major expansion of the mangrove ecosystem across the gradually submerging shelf. The combination during the late Holocene of a reoccurrence of heterotrophic dinoflagellate cysts with increased Poaceae, Cyperaceae and Podocarpus pollen indicates enhanced nutrient supply to the ocean concordant with a shift to cooler/drier conditions over the Gabon basin. This appears to be linked to a deterioration of the monsoon system induced by the low sea-surface temperatures in the tropical Atlantic Ocean in association with decreased summer insolation.     

Soybean seed lipoxygenase genes: molecular characterization and development of molecular marker assays

Soybean seeds contain three lipoxygenase (Lox) enzymes that are controlled by separate genes, Lox1, Lox2 and Lox3. Lipoxygenases play a role in the development of unpleasant flavors in foods containing soybean by oxidation of polyunsaturated fatty acids. Null alleles for all three enzymes have been identified, lox1, lox2 and lox3, and are known to be inherited as simple recessive alleles. Previous studies determined that a missense mutation rendered Lox2 inactive; however, the genetic cause of either lox1 or lox3 mutation was not known. The objectives of this study were the molecular characterization of both lox1 and lox3 mutant alleles and the development of molecular markers to accelerate breeding for Lox-free soybean varieties. We identified two independent mutant alleles as the genetic causes of the lack of Lox1 in seeds of two lox1 mutant soybean lines. Similarly, a mutant allele that truncates Lox3 in a lox3 mutant soybean line was identified. Molecular markers were designed and confirmed to distinguish mutant, wild type, and heterozygous individuals for Lox1, Lox2 and Lox3 genes. Genotype and Lox phenotype analysis showed a perfect association between the inheritance of homozygous lox mutant alleles and the lack of Lox activity. Molecular characterization of a seed-lipoxygenase-free soybean line led to the discovery that an induced recombination event within the Lox1 gene was responsible for breaking the tight linkage in repulsion phase between mutant alleles at the Lox1 and Lox2 loci. The molecular resources developed in this work should accelerate the inclusion of the lipoxygenase-free trait in soybean varieties.     

Classification of rice (<Emphasis Type="Italic">Oryza sativa</Emphasis>l. japonica nipponbare) immunophilins (FKBPs,CYPs) and expression patterns under water stress

Background  

FK506 binding proteins (FKBPs) and cyclophilins (CYPs) are abundant and ubiquitous proteins belonging to the peptidyl-prolyl cis/trans isomerase (PPIase) superfamily, which regulate much of metabolism through a chaperone or an isomerization of proline residues during protein folding. They are collectively referred to as immunophilin (IMM), being present in almost all cellular organs. In particular, a number of IMMs relate to environmental stresses.     

Co-expression of Skp and FkpA chaperones improves cell viability and alters the global expression of stress response genes during scFvD1.3 production

Background  

The overexpression of scFv antibody fragments in the periplasmic space of Escherichia coli frequently results in extensive protein misfolding and loss of cell viability. Although protein folding factors such as Skp and FkpA are often exploited to restore the solubility and functionality of recombinant protein products, their exact impact on cellular metabolism during periplasmic antibody fragment expression is not clearly understood. In this study, we expressed the scFvD1.3 antibody fragment in E. coli BL21 and evaluated the overall physiological and global gene expression changes upon Skp or FkpA co-expression.     

Kalman estimator- and general linear model-based on-line brain activation mapping by near-infrared spectroscopy

Background

Methods of manual cell localization and outlining are so onerous that automated tracking methods would seem mandatory for handling huge image sequences, nevertheless manual tracking is, astonishingly, still widely practiced in areas such as cell biology which are outside the influence of most image processing research. The goal of our research is to address this gap by developing automated methods of cell tracking, localization, and segmentation. Since even an optimal frame-to-frame association method cannot compensate and recover from poor detection, it is clear that the quality of cell tracking depends on the quality of cell detection within each frame.

Methods

Cell detection performs poorly where the background is not uniform and includes temporal illumination variations, spatial non-uniformities, and stationary objects such as well boundaries (which confine the cells under study). To improve cell detection, the signal to noise ratio of the input image can be increased via accurate background estimation. In this paper we investigate background estimation, for the purpose of cell detection. We propose a cell model and a method for background estimation, driven by the proposed cell model, such that well structure can be identified, and explicitly rejected, when estimating the background.

Results

The resulting background-removed images have fewer artifacts and allow cells to be localized and detected more reliably. The experimental results generated by applying the proposed method to different Hematopoietic Stem Cell (HSC) image sequences are quite promising.

Conclusion

The understanding of cell behavior relies on precise information about the temporal dynamics and spatial distribution of cells. Such information may play a key role in disease research and regenerative medicine, so automated methods for observation and measurement of cells from microscopic images are in high demand. The proposed method in this paper is capable of localizing single cells in microwells and can be adapted for the other cell types that may not have circular shape. This method can be potentially used for single cell analysis to study the temporal dynamics of cells.     

Development of a serum-free medium for <Emphasis Type="Italic">in vitro</Emphasis> expansion of human cytotoxic T lymphocytes using a statistical design

Background  

Serum-containing medium (SCM), which has a number of poorly defined components with varying concentrations, hampers standardization of lymphocyte cultures. In order to develop a serum-free medium (SFM) for the expansion of human lymphocytes from peripheral blood mononuclear cells (PBMCs), a statistical optimization approach based on a fractional factorial method and a response surface method was adopted. A basal medium was prepared by supplementing RPMI1640 medium with insulin, albumin, ferric citrate, ethanolamine, fatty acids, glutamine, sodium pyruvate, 2-mercaptoethanol, 1-thioglycerol, nonessential amino acids, and vitamins. We identified additional positive determinants and their optimal concentrations for cell growth through a statistical analysis.     

Origin and Evolution of Sulfadoxine Resistant Plasmodium falciparum

The Thailand-Cambodia border is the epicenter for drug-resistant falciparum malaria. Previous studies have shown that chloroquine (CQ) and pyrimethamine resistance originated in this region and eventually spread to other Asian countries and Africa. However, there is a dearth in understanding the origin and evolution of dhps alleles associated with sulfadoxine resistance. The present study was designed to reveal the origin(s) of sulfadoxine resistance in Cambodia and its evolutionary relationship to African and South American dhps alleles. We sequenced 234 Cambodian Plasmodium falciparum isolates for the dhps codons S436A/F, A437G, K540E, A581G and A613S/T implicated in sulfadoxine resistance. We also genotyped 10 microsatellite loci around dhps to determine the genetic backgrounds of various alleles and compared them with the backgrounds of alleles prevalent in Africa and South America. In addition to previously known highly-resistant triple mutant dhps alleles SGEGA and AGEAA (codons 436, 437, 540, 581, 613 are sequentially indicated), a large proportion of the isolates (19.3%) contained a 540N mutation in association with 437G/581G yielding a previously unreported triple mutant allele, SGNGA. Microsatellite data strongly suggest the strength of selection was greater on triple mutant dhps alleles followed by the double and single mutants. We provide evidence for at least three independent origins for the double mutants, one each for the SGKGA, AGKAA and SGEAA alleles. Our data suggest that the triple mutant allele SGEGA and the novel allele SGNGA have common origin on the SGKGA background, whereas the AGEAA triple mutant was derived from AGKAA on multiple, albeit limited, genetic backgrounds. The SGEAA did not share haplotypes with any of the triple mutants. Comparative analysis of the microsatellite haplotypes flanking dhps alleles from Cambodia, Kenya, Cameroon and Venezuela revealed an independent origin of sulfadoxine resistant alleles in each of these regions.     

Prostaglandin A2 activates intrinsic apoptotic pathway by direct interaction with mitochondria in HL-60 cells

HL-60 cells treated by prostaglandin (PG) A₂ showed characteristics of apoptosis such as accumulation of hypodiploid and annexin V positive cells, condensed and fragmented nuclei, cytochrome c (Cyt C) release from mitochondria and activation of caspase-1, -2, -3, -7 and -9. PGA₂-induced cell death was rescued by inhibitors of caspase-9 and -3, but PGA₂-induced Cyt C release was not prevented by caspase inhibitors. During Cyt C release by PGA₂, mitochondrial transmembrane potential was maintained and mitochondrial permeability transition pore was not formed. In addition, anti-apoptotic BCL-2 family proteins like BCL-2 and BCL-XL, and ROS scavengers including ascorbic acid and 2,2,6,6-tetramethyl-1-piperidinyloxy were not able to inhibit Cyt C release as well as apoptosis by PGA₂. Finally, it was shown that PGA₂-induced Cyt C release in vitro from purified mitochondria in the absence of cytosolic components. Furthermore, thiol-containing compounds such as N-acetylcysteine, l-cysteine and monothioglycerol prevented Cyt C release, and hence induction of apoptosis. Taken together, these results suggest that PGA₂ activates intrinsic apoptotic pathway by directly stimulating mitochondrial outer membrane permeabilization to release Cyt C, in which thiol-reactivity of PGA₂ plays a pivotal role.     

Occurrence and fate of fetal lumbar rib induced by Scutellariae radix in rats

BACKGROUND: This study was conducted to evaluate the occurrence and fate of fetal lumbar rib induced by Scutellariae radix (SR) in rats. METHODS: Water extracts of SR were orally administered to pregnant rats from day 7 to day 17 of gestation at a dose of 186 mg/kg/day, equivalent to 25 g/kg of starting material, representing a 100‐fold increase over typical human intake level. RESULTS: The incidence of fetal lumbar rib in the SR‐treated group was increased on gestational day 20 and then decreased on postnatal day 50. The weight of fetuses in the SR‐treated group tended to be less than that in the control group. Alkaline phosphatase in SR‐treated dams was increased on gestational day 20, but was decreased on postnatal day 50. There were no significant differences between the vehicle control and SR‐treated groups in maternal body weight, embryological, histopathological, hematological, and serum biochemical changes. CONCLUSIONS: The present data suggest that the appearance of lumbar rib induced by SR is a transient fetal variation rather than teratogenicity or maternal toxicity. Birth Defects Res (Part B) 89:201–206, 2010. © 2010 Wiley‐Liss, Inc.