Morphological changes in the bovine articular cartilage subjected to moderate and high loadings.

This study aims at examining the morphological changes in the cartilage structure of the bovine knee joint when the amputated joints are subjected to (a) a moderate load of 150 kg and (b) a high load of 300 kg and fitted on a knee joint articulating machine at 45 cycles/min for 2 h. The scanning-microscopic study of the surface structure of the experimental and control cartilage shows no appreciable change in the surface morphology of the cartilage when subjected to the moderate load of 150 kg. However, in the case of the high load (300 kg) there is appreciable change in the fibrillary structural pattern of the surface morphology. Histologically too, no appreciable change was noticed when subjected to moderate loadings, but in the case of high loading the cartilage develops roughness of the surface with occasional small clefts.     

Probing the nucleus model for oligomer formation during insulin amyloid fibrillogenesis

We find evidence for a direct transition of insulin monomers into amyloid fibrils without measurable concentrations of oligomers or protofibrils, suggesting that fibrillogenesis may occur directly from assembly of denaturing insulin monomers rather than by successive transitions through protofibril nuclei. To support our finding, we obtain size distributions using electrospray differential mobility analysis (ES-DMA), which provides excellent resolution to clearly distinguish among small oligomers and rapidly generates statistically significant size distributions. The distributions detect an absence of significant peaks between 6 nm and 17 nm as the monomer reacts into fibers—exactly the size range observed by others for small-angle-neutron-scattering-measured intermediates and for circular supramolecular structures. They report concentrations in the nanomolar range, whereas our limit of detection remains three-orders-of-magnitude lower (<5 pmol/L). This finding, along with the lack of significant increases in the β-sheet content of monomers using circular dichroism, suggests monomers do not first structurally rearrange and accumulate in a β-rich state but react and reorganize at the growing fiber's tip. These results quantitatively inform reaction-based theories of amyloid fiber formation and have implications for neurodegenerative, protein conformation ailments including Alzheimer's disease and bovine spongiform encephalopathy.     

Influence of extrinsic factors on granulation in UASB reactor

The aim of this mini-review is to synthesize and analyze information on how the process of granulation is affected by environmental and operational conditions in the reactor. The factors reviewed are temperature, pH, alkalinity, organic loading rate, upflow velocity, nature and strength of substrate, nutrients, multivalent cations and heavy metals, microbial ecology of seed sludge, exo-cellular polymer, and addition of natural and synthetic polymers. Careful temperature control and adequate alkalinity is required for generation and maintenance of granules. Nature and strength of substrate in conjunction with intra-granular diffusion to a large extent determines the microstructure of the granules. The divalent cations such as calcium and iron may enhance granulation by ionic bridging and linking exo-cellular polymers. However, their presence in excess may lead to cementation due to precipitation leading to increased ash content and mass transfer limitation. The addition of external additives such as ionic polymers may enhance granulation in the upflow anaerobic sludge blanket reactors.     

Extracellular vesicles--vehicles that spread cancer genes

Once regarded as cellular 'debris' extracellular vesicles (EVs) emerge as one of the most intriguing entities in cancer pathogenesis. Intercellular trafficking of EVs challenges the notion of cancer cell autonomy, and highlights the multicellular nature of such fundamental processes as stem cell niche formation, tumour stroma generation, angiogenesis, inflammation or immunity. Recent studies reveal that intercellular exchange mediated by EVs runs deeper than expected, and includes molecules causative for cancer progression, such as oncogenes (epidermal growth factor receptor, Ras), and tumour suppressors (PTEN). The uptake of oncogenic EVs (oncosomes) by various cells may profoundly change their biology, signalling patterns and gene expression, and in some cases cause their overt tumorigenic conversion. Moreover, EVs circulating in blood and present in body fluids provide an unprecedented access to the molecular circuitry driving cancer cells, and new technologies are being developed to exploit this property as a source of unique cancer biomarkers.     

Profile of the GSK Published Protein Kinase Inhibitor Set Across ATP-Dependent and-Independent Luciferases: Implications for Reporter-Gene Assays

A library of 367 protein kinase inhibitors, the GSK Published Kinase Inhibitor Set (PKIS), which has been annotated for protein kinase family activity and is available for public screening efforts, was assayed against the commonly used luciferase reporter enzymes from the firefly, Photinus pyralis (FLuc) and marine sea pansy, Renilla reniformis (RLuc). A total of 22 compounds (∼6% of the library) were found to inhibit FLuc with 10 compounds showing potencies ≤1 µM. Only two compounds were found to inhibit RLuc, and these showed relatively weak potency values (∼10 µM). An inhibitor series of the VEGFR2/TIE2 protein kinase family containing either an aryl oxazole or benzimidazole-urea core illustrate the different structure activity relationship profiles FLuc inhibitors can display for kinase inhibitor chemotypes. Several FLuc inhibitors were broadly active toward the tyrosine kinase and CDK families. These data should aid in interpreting the results derived from screens employing the GSK PKIS in cell-based assays using the FLuc reporter. The study also underscores the general need for strategies such as the use of orthogonal reporters to identify kinase or non-kinase mediated cellular responses.     

Relationship between nutritional state and testes function, together with observations on patterns of feeding, in the toad, Bufo bufo bufo

The effects of 10 weeks of starvation, restricted feeding, or ad lib. feeding on nutritional state and testes functions were investigated in male toads that had artificially hibernated in a refrigerator before being placed at room temperature. Food intake increased for about four weeks in both the fed groups. After this initial period the toads on restricted food ate their ration for the remaining part of the experiment, and they developed fat bodies of sizes characteristic of male toads during late summer in nature. The toads fed ad lib. increased food intake to about twice that of those on restricted food. After two weeks of high feeding rate food intake rapidly declined and remained low to the end of the experiment, when the fat bodies were larger than normally seen in nature. At the end of the experiment spermatogenetic activity had declined to a low level in the starving toads, whereas it was high in the fed toads. Starvation for 10 weeks did not affect the late stages of spermatogenesis. Interstitial cells and thumbpads remained reduced in the starving toads, but were restored in the fed toads. The importance of the annual cycle in nutritional state for gonadal cycles in male and female toads is discussed.     

Mitochondrial retrograde signaling at the crossroads of tumor bioenergetics,genetics and epigenetics

Mitochondria play a central role not only in energy production but also in the integration of metabolic pathways as well as signals for apoptosis and autophagy. It is becoming increasingly apparent that mitochondria in mammalian cells play critical roles in the initiation and propagation of various signaling cascades. In particular, mitochondrial metabolic and respiratory states and status on mitochondrial genetic instability are communicated to the nucleus as an adaptive response through retrograde signaling. Each mammalian cell contains multiple copies of the mitochondrial genome (mtDNA). A reduction in mtDNA copy number has been reported in various human pathological conditions such as diabetes, obesity, neurodegenerative disorders, aging and cancer. Reduction in mtDNA copy number disrupts mitochondrial membrane potential (Δψm) resulting in dysfunctional mitochondria. Dysfunctional mitochondria trigger retrograde signaling and communicate their changing metabolic and functional state to the nucleus as an adaptive response resulting in an altered nuclear gene expression profile and altered cell physiology and morphology. In this review, we provide an overview of the various modes of mitochondrial retrograde signaling focusing particularly on the Ca^2 +/Calcineurin mediated retrograde signaling. We discuss the contribution of the key factors of the pathway such as Calcineurin, IGF1 receptor, Akt kinase and HnRNPA2 in the propagation of signaling and their role in modulating genetic and epigenetic changes favoring cellular reprogramming towards tumorigenesis.     

CUL4-DDB1-CDT2 E3 Ligase Regulates the Molecular Clock Activity by Promoting Ubiquitination-Dependent Degradation of the Mammalian CRY1

The CUL4-DDB1 E3 ligase complex serves as a critical regulator in various cellular processes, including cell proliferation, DNA damage repair, and cell cycle progression. However, whether this E3 ligase complex regulates clock protein turnover and the molecular clock activity in mammalian cells is unknown. Here we show that CUL4-DDB1-CDT2 E3 ligase ubiquitinates CRY1 and promotes its degradation both in vitro and in vivo. Depletion of the major components of this E3 ligase complex, including Ddb1, Cdt2, and Cdt2-cofactor Pcna, leads to CRY1 stabilization in cultured cells or in the mouse liver. CUL4A-DDB1-CDT2 E3 ligase targets lysine 585 within the C-terminal region of CRY1 protein, shown by the CRY1 585KA mutant’s resistance to ubiquitination and degradation mediated by the CUL4A-DDB1 complex. Surprisingly, both depletion of Ddb1 and over-expression of Cry1-585KA mutant enhance the oscillatory amplitude of the Bmal1 promoter activity without altering its period length, suggesting that CUL4A-DDB1-CDT2 E3 targets CRY1 for degradation and reduces the circadian amplitude. All together, we uncovered a novel biological role for CUL4A-DDB1-CDT2 E3 ligase that regulates molecular circadian behaviors via promoting ubiquitination-dependent degradation of CRY1.