Control of cellulose hydrolysis by fungi

Summary The extent of filter paper degradation by extracellular preparations fromT. reesei and its mutants with a decreasing level of -glucosidase and an increasing level of endoglucanase has been determined. The ability to degrade cellulose is restricted by the level of endoglucanase and not by -glucosidase.     

Centripetal Acceleration Reaction: An Effective and Robust Mechanism for Flapping Flight in Insects

Despite intense study by physicists and biologists, we do not fully understand the unsteady aerodynamics that relate insect wing morphology and kinematics to lift generation. Here, we formulate a force partitioning method (FPM) and implement it within a computational fluid dynamic model to provide an unambiguous and physically insightful division of aerodynamic force into components associated with wing kinematics, vorticity, and viscosity. Application of the FPM to hawkmoth and fruit fly flight shows that the leading-edge vortex is the dominant mechanism for lift generation for both these insects and contributes between 72–85% of the net lift. However, there is another, previously unidentified mechanism, the centripetal acceleration reaction, which generates up to 17% of the net lift. The centripetal acceleration reaction is similar to the classical inviscid added-mass in that it depends only on the kinematics (i.e. accelerations) of the body, but is different in that it requires the satisfaction of the no-slip condition, and a combination of tangential motion and rotation of the wing surface. Furthermore, the classical added-mass force is identically zero for cyclic motion but this is not true of the centripetal acceleration reaction. Furthermore, unlike the lift due to vorticity, centripetal acceleration reaction lift is insensitive to Reynolds number and to environmental flow perturbations, making it an important contributor to insect flight stability and miniaturization. This force mechanism also has broad implications for flow-induced deformation and vibration, underwater locomotion and flows involving bubbles and droplets.     

Acrosin activity in spermatozoa from sterile t6/tw32 and fertile control mice

Spermatozoa from sterile t6/tw32 and control fertile +/+, T/tw32, T/t6 mice were compared for their abilities to hydrolyse protein matrices and for their levels of acrosin activity. The data show that the immature and mature gametes from both the experimental and control males hydrolyse protein matrices. The quantitative acrosin assays show, however, that the mature gametes from the intercomplement males have significantly less total acrosin activity than any of the control groups of gametes. These findings suggest that this reduced acrosin activity is an additional phenotypic expression of the intercomplement genotype which results in male sterility.     

Schlafen-3 decreases cancer stem cell marker expression and autocrine/juxtacrine signaling in FOLFOX-resistant colon cancer cells

We have previously demonstrated that expression of the novel gene schlafen-3 (Slfn-3) correlates with intestinal epithelial cell differentiation (Patel VB, Yu Y, Das JK, Patel BB, Majumdar AP. Biochem Biophys Res Commun 388: 752-756, 2009). The present investigation was undertaken to examine whether Slfn-3 plays a role in regulating differentiation of FOLFOX-resistant (5-fluorouracil + oxaliplatin) colon cancer cells that are highly enriched in cancer stem cells (CSCs). Transfection of Slfn-3 in FOLFOX-resistant colon cancer HCT-116 cells resulted in increase of alkaline phosphatase activity, a marker of intestinal differentiation. Additionally, Slfn-3 transfection resulted in reduction of mRNA and protein levels of the CSC markers CD44, CD133, CD166, and aldehyde dehydrogenase 1 in both FOLFOX-resistant HCT-116 and HT-29 cells. This was accompanied by decreased formation of tumorosphere/colonosphere (an in vitro model of tumor growth) in stem cell medium and inhibition of expression of the chemotherapeutic drug transporter protein ABCG2. Additionally, Slfn-3 transfection of FOLFOX-resistant HCT-116 and HT-29 cells reduced Hoechst 33342 dye exclusion. Finally, Slfn-3 transfection inhibited the expression of transforming growth factor-α in both FOLFOX-resistant colon cancer cells, but stimulated apoptosis in response to additional FOLFOX treatment. In summary, our data demonstrate that Slfn-3 expression inhibits multiple characteristics of CSC-enriched, FOLFOX-resistant colon cancer cells, including induction of differentiation and reduction in tumorosphere/colonosphere formation, drug transporter activity, and autocrine stimulation of proliferation. Thus Slfn-3 expression may render colon CSCs more susceptible to cancer chemotherapeutics.     

A comparative study of the epidermis of the common carp and the three Indian major carp

A comparative study has been made of the mucogenic epidermis of the common carp, Cyprinus carpio var. communis, and the three Indian major carps, Catla catla, Labeo rohita and Cirrhina mrigala: on the basis of epidermis structural organization, these species are easily differentiated. The epithelial cells in the superficial layer, as in most fishes, show secretory activity, evidenced by positive histochemical reactions, which is high in C. carpio var. communis, moderate in C. catla and low in L. rohita and C. mrigala. The epithelial cells in the underlying two or three layers also give positive reactions, though their intensity is relatively weak. The mucous cells in C. carpio var. communis are distributed in large numbers arranged in several superimposed layers in the outer regions of the epidermis, whereas in C. catla they are fewer in number and are widely separated in the surface layers as well as in the deeper layers of the epidermis; in both species the mucous cells appear rounded, large, and open on the surface by wide pores. In contrast, in L. rohita and C. mrigala the mucous cells are smaller, restricted mainly to the superficial layer, close together in a single row, and open on the surface by narrow pores. The overall density of mucous cells in L. rohita and C. mrigala, as in C. catla, is much lower than in C. carpio var. communis. In the epidermis of C. carpio var. communis there are a large number of mucous cells, and the few club cells are restricted to the deeper layers. In contrast, in the epidermis of the three Indian major carp the overall density of the mucous cells is much lower and the club cells are very numerous. It is suggested that the high density of club cells compensates an overall low density of mucous cells as an adaptation for an effective defence mechanism. Increased mucus production in the epidermis of C. carpio var. communis, as evidenced by a large number of mucous cells in outer regions and high secretory activity of superficial layer epithelial cells, is associated with increased precipitation of mud held in suspension, needed as an adaptation to the species’peculiar bottom-scooping habits. The varied density of the taste buds in the epidermis of the four carp is associated with their feeding habits.     

PSCA gene variants (rs2294008 and rs2978974) confer increased susceptibility of gallbladder carcinoma in females

Background and aim

PSCA is a tissue specific tumor suppressor or oncogene which has been found to be associated with several human tumors including gallbladder cancer. It is considered to be involved in the cell-proliferation inhibition and/or cell-death induction activity. Therefore, we aimed to investigate the role of PSCA gene polymorphisms in gallbladder cancer risk in North Indian population.

Methodology

A total of 405 gallbladder cancer patients and 247 healthy controls were included in the case–control study for risk prediction. We examined the association of two functional SNPs, rs2294008 and rs2978974 in PSCA gene by genotyping using Taqman allelic discrimination assays. Statistical analysis was done using SPSS software, version 17. Linkage disequilibrium and haplotype analysis was done with the help of SNPstats software. FDR test was used to correct for multiple comparisons.

Results

No significant associations of rs2294008 and rs2978974 genetic variants of the PSCA gene were found with GBC risk at allele, genotype or haplotype levels. Stratifying the subjects on the basis of gallstone also did not show any significant result. However, on gender stratification, we found a significant association of T_rs2294008-G_rs2978974 haplotype with higher risk of GBC in females (FDR Pcorr = 0.021, OR = 1.6). In contrary, T_rs2294008-A _rs2978974 haplotype conferred significant lower risk in males (FDR Pcorr = 0.013; OR = 0.25).

Conclusions

These findings suggest that PSCA genetic variants may have a significant effect on GBC susceptibility in a gender specific manner.     

Association genetics of the parameters related to nitrogen use efficiency in Brassica juncea L.

Key message

Genome wide association studies allowed prediction of 17 candidate genes for association with nitrogen use efficiency. Novel information obtained may provide better understanding of genomic controls underlying germplasm variations for this trait in Indian mustard.

Abstract

Nitrogen use efficiency (NUE) of Indian mustard (Brassica juncea (L.) Czern & Coss.) is low and most breeding efforts to combine NUE with crop performance have not succeeded. Underlying genetics also remain unexplored. We tested 92 SNP-genotyped inbred lines for yield component traits, N uptake efficiency (NUPEFF), nitrogen utilization efficiency (NUTEFF), nitrogen harvest index (NHI) and NUE for two years at two nitrogen doses (N_o without added N and N₁₀₀ added @100 kg/ha). Genotypes IC-2489-88, M-633, MCP-632, HUJM 1080, GR-325 and DJ-65 recorded high NUE at low N. These also showed improved crop performance under high N. One determinate mustard genotype DJ-113 DT-3 revealed maximum NUTEFF. Genome wide association studies (GWAS) facilitated recognition of 17 quantitative trait loci (QTLs). Environment specificity was high. B-genome chromosomes (B02, B03, B05, B07 and B08) harbored many useful loci. We also used regional association mapping (RAM) to supplement results from GWAS. Annotation of the genomic regions around peak SNPs helped to predict several gene candidates for root architecture, N uptake, assimilation and remobilization. CAT9 (At1g05940) was consistently envisaged for both NUE and NUPEFF. Major N transporter genes, NRT1.8 and NRT3.1 were predicted for explaining variation for NUTEFF and NUPEFF, respectively. Most significant amino acid transporter gene, AAP1 appeared associated with NUE under limited N conditions. All these candidates were predicted in the regions of high linkage disequilibrium. Sequence information of the predicted candidate genes will permit development of molecular markers to aid breeding for high NUE.

     

Antibody-functionalized fluid-permeable surfaces for rolling cell capture at high flow rates

Adhesion-based cell capture on surfaces in microfluidic devices forms the basis of numerous biomedical diagnostics and in vitro assays. However, the performance of these platforms is partly limited by interfacial phenomena that occur at low Reynolds numbers. In contrast, cell homing to porous vasculature is highly effective in vivo during inflammation, stem cell trafficking, and cancer metastasis. Here, we show that a porous, fluid-permeable surface functionalized with cell-specific antibodies promotes efficient and selective cell capture in vitro. This architecture is advantageous due to enhanced transport as streamlines are diverted toward the surface. Moreover, specific cell-surface interactions are promoted due to reduced shear, allowing gentle cell rolling and arrest. Together, these synergistic effects enable highly effective cell capture at flow rates more than an order of magnitude larger than those provided by existing devices with solid surfaces.