Isolation of the protein tyrosine phosphatase 1B inhibitory metabolite from the marine-derived fungus Cosmospora sp. SF-5060

In the course of bioassay-guided study on the EtOAc extract of a culture broth of the marine-derived fungus Cosmospora sp. SF-5060, aquastatin A (1) was isolated as a protein tyrosine phosphatase 1B (PTP1B) inhibitory component produced by the fungus. The compound was isolated by various chromatographic methods, and the structure was determined mainly by analysis of NMR spectroscopic data. Compound 1 exhibited potent inhibitory activity against PTP1B with IC₅₀ value of 0.19 μM, and the kinetic analyses of PTP1B inhibition by compound 1 suggested that the compound is inhibiting PTP1B activity in a competitive manner. Aquastatin A (1) also showed modest but selective inhibitory activity toward PTP1B over other protein tyrosine phosphatases, such as TCPTP, SHP-2, LAR, and CD45. In addition, the result of hydrolyzing aquastatin A (1) suggested that the dihydroxypentadecyl benzoic acid moiety in the molecule is responsible for the inhibitory activity.     

Jasmonate-dependent plant defense restricts thrips performance and preference

Background  

The western flower thrips (Frankliniella occidentalis [Pergande]) is one of the most important insect herbivores of cultivated plants. However, no pesticide provides complete control of this species, and insecticide resistance has emerged around the world. We previously reported the important role of jasmonate (JA) in the plant's immediate response to thrips feeding by using an Arabidopsis leaf disc system. In this study, as the first step toward practical use of JA in thrips control, we analyzed the effect of JA-regulated Arabidopsis defense at the whole plant level on thrips behavior and life cycle at the population level over an extended period. We also studied the effectiveness of JA-regulated plant defense on thrips damage in Chinese cabbage (Brassica rapa subsp. pekinensis).     

A Modified Delta-Shaped Gastroduodenostomy in Totally Laparoscopic Distal Gastrectomy for Gastric Cancer: A Safe and Feasible Technique

Background

The present study introduced a modified delta-shaped gastroduodenostomy (DSG) technique and assessed the safety, feasibility and clinical results of this procedure in patients undergoing totally laparoscopic distal gastrectomy (TLDG) for gastric cancer (GC).

Materials and Methods

A total of 102 patients with distal GC undergoing TLDG with modified DSG between January 2013 and December 2013 were enrolled. A retrospective study was performed using a prospectively maintained comprehensive database to evaluate the results of the procedure. Univariate and multivariate analyses were performed to estimate the predictive factors for postoperative morbidity.

Results

The mean operation time was 150.6±30.2 min, the mean anastomosis time was 12.2±4.2 min, the mean blood loss was 48.2±33.2 ml, and the mean times to first flatus, fluid diet, soft diet and postoperative hospital stay were 3.8±1.3 days, 5.0±1.0 days, 7.4±2.1 days and 12.0±6.5 days, respectively. Two patients with minor anastomotic leakage after surgery were managed conservatively; no patient experienced any complications around the anastomosis, such as anastomotic stricture or anastomotic hemorrhage. Univariate analysis showed that age, gastric cancer with hemorrhage and cardiovascular disease combined were significant factors that affected postoperative morbidity (P<0.05). Multivariate analysis found that gastric cancer with hemorrhage was the independent risk factor for the postoperative morbidity (P = 0.042). At a median follow-up of 7 months, no patients had died or experienced recurrent or metastatic disease.

Conclusions

The modified DSG was technically safe and feasible, with acceptable surgical outcomes, in patients undergoing TLDG for GC, and this procedure may be promising in these patients.     

Reprogramming of sugar transport pathways in Escherichia coli using a permeabilized SecY protein-translocation channel

In the initial step of sugar metabolism, sugar-specific transporters play a decisive role in the passage of sugars through plasma membranes into cytoplasm. The SecY complex (SecYEG) in bacteria forms a membrane channel responsible for protein translocation. The present work shows that permeabilized SecY channels can be used as nonspecific sugar transporters in Escherichia coli. SecY with the plug domain deleted allowed the passage of glucose, fructose, mannose, xylose, and arabinose, and, with additional pore-ring mutations, facilitated lactose transport, indicating that sugar passage via permeabilized SecY was independent of sugar stereospecificity. The engineered E. coli showed rapid growth on a wide spectrum of monosaccharides and benefited from the elimination of transport saturation, improvement in sugar tolerance, reduction in competitive inhibition, and prevention of carbon catabolite repression, which are usually encountered with native sugar uptake systems. The SecY channel is widespread in prokaryotes, so other bacteria may also be engineered to utilize this system for sugar uptake. The SecY channel thus provides a unique sugar passageway for future development of robust cell factories for biotechnological applications.     

Enhancing the processivity of a family B-type DNA polymerase of Thermococcus onnurineus and application to long PCR

Mechanisms that allow replicative DNA polymerases to attain high processivity are often specific to a given polymerase and cannot be generalised to others. Amplification efficiency is lower in family B-type DNA polymerases than in family A-type (Taq) polymerases because of their strong 3′–5′ exonuclease-activity. Here, we have red the exonuclease domain of the Thermococcus onnurineus NA1 (TNA1) DNA polymerase, especially Asn210 to Asp215 residues in Exo II motif (NXXXFD), to improve the processivity. N213D mutant protein had higher processivity and extension rate than the wild-type TNA1 DNA polymerase, retaining a lower mutation frequency than recombinant Taq DNA polymerase. Consequently, the N213D mutant could amplify target DNA up to 13.5 kb in length from human genomic DNA and 16.2 kb in length from human mitochondrial DNA while wild-type TNA1 amplified target DNA of 2.7 kb in length from human genomic DNA.     

Conservation genetics of highly isolated populations of the xerothermic beetle Crioceris quatuordecimpunctata (Chrysomelidae)

Xerothermic species are rare and threatened in central and eastern Europe. In light of the continuing loss of steppe‐like habitats due to anthropogenic fragmentation and degradation, the evaluation of genetic variation in populations inhabiting them is of immediate importance if appropriate conservation measures are to be undertaken. Here we report on the genetic diversity of the rare leaf beetle Crioceris quatuordecimpunctata, whose populations in central and eastern Europe inhabit highly geographically isolated areas. All of the studied populations (in Poland, Ukraine, and Slovakia) were differentiated at the mitochondrial marker COI. However, with respect to the nuclear marker ITS1, Polish populations were monomorphic, but distinct from all other populations. The distinctiveness of the studied populations was confirmed by Wolbachia screening, which showed that all populations carried different strains (one or two), which were probably transferred independently from other insects. On the other hand, no diversity was found in any marker within particular populations, which could be caused (at least for mtDNA) by a Wolbachia selective sweep. Crioceris quatuordecimpunctata probably consists of isolated populations, which went through narrow bottlenecks leading to a drastic reduction in their genetic diversity. As these populations are reciprocally monophyletic for mtDNA haplotypes and show a significant divergence of allele frequencies at nuclear loci, they could be classified as evolutionarily significant units (ESUs). In addition, DNA barcodes were used to identify Asparagus officinalis as the host plant for members of all studied populations. These data should be valuable in efforts to conserve populations of C. quatuordecimpunctata (e.g., for guiding reintroductions).     

Cigarette Smoking Increases Abdominal and Visceral Obesity but Not Overall Fatness: An Observational Study

Background

Cigarette smoking and obesity are leading public health concerns. Both increase the risk for cardiovascular disease, cancer, and metabolic abnormalities. This study was conducted to assess the association between cigarette smoking and different types of obesity.

Methodology/Principal Findings

Two hundred eighty-three visitors to university hospitals located in four main provinces of South Korea were participated. All participants were classified as either current/past or never smokers and were divided into quartiles according to the total pack-years. Body mass index, waist circumference, total body fat percentage, and area of visceral and abdominal subcutaneous fat were measured. These results of each groups were compared. Waist circumference, and visceral fat area showed a J- or U-shaped association with total smoking amount during a lifetime. After restricting the analyses to past/current smokers, we found significant dose-dependent associations of smoking pack-years with abdominal and visceral obesity. Overall obesity measured by body mass index and total body fat percentage did not show such associations. Although current smokers clearly showed significant associations, we could not demonstrate these in past smokers, possibly because of the limited sample size.

Conclusions/Significance

Although smokers did not show significant difference in mean body mass index than those who never smoked, they showed more metabolically adverse fat distributions with increasing smoking amounts. This finding suggests that smoking is not beneficial for weight control. Therefore, smoking cessation and avoidance of smoking commencement should be addressed as important public health issues in preventing obesity and related complications.     

Identification of a cyanobacterial CRR6 protein,Slr1097, required for efficient assembly of NDH‐1 complexes in Synechocystis sp. PCC 6803

Despite significant progress in clarifying the subunit compositions and functions of the multiple NADPH dehydrogenase (NDH‐1) complexes in cyanobacteria, the subunit maturation and assembly of their NDH‐1 complexes are poorly understood. By transformation of wild‐type cells with a transposon‐tagged library, we isolated three mutants of Synechocystis sp. PCC 6803 defective in NDH‐1‐mediated cyclic electron transfer and unable to grow under high light conditions. All the mutants were tagged in the same slr1097 gene, encoding an unknown protein that shares significant homology with the Arabidopsis protein chlororespiratory reduction 6 (CRR6). The slr1097 product was localized in the cytoplasm and was required for efficient assembly of NDH‐1 complexes. Analysis of the interaction of Slr1097 with 18 subunits of NDH‐1 complexes using a yeast two‐hybrid system indicated a strong interaction with NdhI but not with other Ndh subunits. Absence of Slr1097 resulted in a significant decrease of NdhI in the cytoplasm, but not of other Ndh subunits including NdhH, NdhK and NdhM; the decrease was more evident in the cytoplasm than in the thylakoid membranes. In the ?slr1097 mutant, NdhH, NdhI, NdhK and NdhM were hardly detectable in the NDH‐1M complex, whereas almost half the wild‐type levels of these subunits were present in NDH‐1L complex; similar results were observed in the NdhI‐less mutant. These results suggest that Slr1097 is involved in the maturation of NdhI, and that assembly of the NDH‐1M complex is strongly dependent on this factor. Maturation of NdhI appears not to be crucial to assembly of the NDH‐1L complex.