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[en] According to the Oparin-Haldane Hypothesis the Origin of Life is a necessary consequence of the evolutionary process in the Universe. The idea of life arising from non life is inherent in the philosophy and literature of the ancient thinkers and writers. The concept of spontaneous generation is today presented with a more scientific basis, under the heading of chemical evolution. The modern thinking is based on the astronomical concept that the conditions suitable for life are commonplace in the universe. Modern biochemistry has highlighted the unity of all living matter. Nucleic acids and proteins constitute the building blocks of life. The Darwinian theory of evolution has outlined the sequence from the first cell to the origin of intelligence. Since the laws of physics and chemistry are universal laws the chemical evolution that has taken place on earth must have happened elsewhere in the Universe. It is reasonable to believe that intelligent life must also be present beyond the earth. (author)
[en] The presence of tetrahedrally divided tatrasporangia in Ceramium bisporum ballantine is reported for the first time. The plant was found as epiphytic on calcareous Halimeda tuna in coral reef environment in Caribbean Colombia. The taxon represents a new record for the country.
[en] Pairing of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins on vesicles (v-SNAREs) and SNARE proteins on target membranes (t-SNAREs) mediates intracellular membrane fusion. VAMP3/cellubrevin is a v-SNARE that resides in recycling endosomes and endosome-derived transport vesicles. VAMP3 has been implicated in recycling of transferrin receptors, secretion of α-granules in platelets, and membrane trafficking during cell migration. Using a cell fusion assay, we examined membrane fusion capacity of the ternary complexes formed by VAMP3 and plasma membrane t-SNAREs syntaxin1, syntaxin4, SNAP-23 and SNAP-25. VAMP3 forms fusogenic pairing with t-SNARE complexes syntaxin1/SNAP-25, syntaxin1/SNAP-23 and syntaxin4/SNAP-25, but not with syntaxin4/SNAP-23. Deletion of the N-terminal domain of syntaxin4 enhanced membrane fusion more than two fold, indicating that the N-terminal domain negatively regulates membrane fusion. Differential membrane fusion capacities of the ternary v-/t-SNARE complexes suggest that transport vesicles containing VAMP3 have distinct membrane fusion kinetics with domains of the plasma membrane that present different t-SNARE proteins
[en] Lysosomes are intracellular organelles which contain enzymes and activator proteins involved in the digestion and recycling of a variety of cellular and extracellular substances. We have identified a novel sorting receptor, sortilin, which is involved in the lysosomal trafficking of the sphingolipid activator proteins, prosaposin and GM2AP, and the soluble hydrolases cathepsin D, cathepsin H, and acid sphingomyelinase. Sortilin belongs to a growing family of receptors with homology to the yeast Vps10 protein, which acts as a lysosomal sorting receptor for carboxypeptidase Y. In this study we examined the effects of the sortilin gene inactivation in mice. The inactivation of this gene did not yield any noticeable lysosomal pathology. To determine the existence of an alternative receptor complementing the sorting function of sortilin, we quantified the concentration of prosaposin in the lysosomes of the nonciliated epithelial cells lining the efferent ducts. These cells were chosen because they express sortilin and have a large number of lysosomes containing prosaposin. In addition, the nonciliated cells are known to endocytose luminal prosaposin that is synthesized and secreted by Sertoli cells into the seminiferous luminal fluids. Consequently, the nonciliated cells are capable of targeting both exogenous and endogenous prosaposin to the lysosomes. Using electron microscope immunogold labeling and quantitative analysis, our results demonstrate that inactivation of the sortilin gene produces a significant decrease of prosaposin in the lysosomes. When luminal prosaposin was excluded from the efferent ducts, the level of prosaposin in lysosomes was even lower in the mutant mice. Nonetheless, a significant amount of prosaposin continues to reach the lysosomal compartment. These results strongly suggest the existence of an alternative receptor that complements the function of sortilin and explains the lack of lysosomal storage disorders in the sortilin-deficient mice.
[en] The scope of microautoradiography as a cytological technique is briefly outlined. Established metabolic pathways and molecular structures provide numerous possibilities for generating radiochemicals which can serve as specific biochemical markers in microautoradiography. The anatomical discrimination available depends on the thickness of the specimen, the range of the radiation creating the image, the size of the emulsion crystals and the type of development process used. The most highly discriminating systems reveal and quantify radioactivity in small organelles and membranes within individual cells. More crudely used, the method reveals the activity in individual cells among a population or particular local areas of extracellular matrix. Image deconvolution techniques are currently being explored to improve the anatomical and chemical discrimination in the autoradiographic examination of solitary free cells. (U.K.)
[en] To investigate the prognostic significance of creatine kinase (CK) in Pakistani patients suffering from acute myocardial infarction (AMI) and to find out if CK combined with troponin T (TnT) could be a better predictor for long-term adverse cardiac event. One hundred and eighty six consecutive patients with AMI who were eligible for streptokinase (SK) treatment were included in this prospective cohort study. The relationship between their serum plasma CK and TnT levels at the time of admission and clinical outcome was investigated over a mean follow up of 24.12 +- 3.75 months. Admission CK was found to be associated with subsequent cardiac event and mortality (P< 0.01 and P< 0.04 respectively). Admission CK was also mildly associated with time interval between onsets of symptoms to SK treatment (correlation coefficient 'r' = 0.23). Odds of encountering a cardiac event in AMI patients with above-normal CK levels (adjusted for gender) were 3.46 times higher than the odds in patients with normal CK levels. Similarly, odds of mortality in patients with positive TnT were 4.6 times the odds in patients with negative TnT. The two biochemical markers, CK and TnT, together did not provide any further information about prognosis of the disease. Admission CK is a better prognostic marker for a subsequent cardiac event, while TnT is a better predictor of mortality over a mean follow up of nearly 2 years. Together, they do not improve predictability of an adverse cardiac event (JPMA 59:819; 2009). (author)
[en] The dynamics of long-run glycolytic metabolism is assessed in nitrogen-laser-(337.1 nm)irradiated yeast cells for different doses at various time lags (from one to fourteen days) after the insult. A non-monotonic memory effect is evident from the enhancement in metabolic-enzyme activity on the first and the last day of observation and inhibition on the tenth day. Recovery from inhibited to normal state is shown to occur upon a subsequent treatment of insulted cells with a HeNe laser (632.8 nm) radiation with no noticeable difference depending on its state of coherence
[en] To compare the histological prognostic markers in breast carcinoma over three decades in Northern Pakistani population and analyze for any change in trends in terms of prognostic markers. Cross-sectional descriptive study was carried out from January 2004 to December 2006 at AFIP, Rawalpindi on 822 cases of female breast carcinoma. Assessment of tumour size on gross examination followed by microscopic evaluation of tumour type, tumour grade, lymph node metastasis and skin involvement was done. The results of the present data were compared with studies of Wahid et al (January 1994 to December 1997) and Malik et al (January 1984 to December 1986) from the same institute. Total 822 cases of breast cancer were diagnosed with 541(64.9%) cases of mastectomy. The mean age was 48+-12years with a mean tumour size of 4.6+-2 cm. A tumour size of >5cm was seen in 30.6% cases and only 18.8% cases had a size <2 cm. Infiltrating ductal carcinoma was the commonest subtype in 674 (81%) cases with histological grade II in 533(64%) cases. Lymph node metastasis was present in 74.6% cases and skin involvement in 36% cases. The comparison of the results of the present study with those over the past two decades in Pakistan show that the mean age at diagnosis remains around 48 years. There is statistically significant increase in the tumours of <5cm at presentation and a higher frequency of tumours with dermal invasion. No significant change is seen in frequency of lymph node metastasis at operation and tumour grade. The comparison of results of other studies done over the past three decades in the region are not very encouraging. The age of presentation remains younger as compared to the West. A positive note is seen in terms of a decreasing tumour size but lack of DCIS cases in our material underlines the need of mammography and launching of effective screening programmes at the national level. Early detection of cases will help in treatment and subsequently improve prognosis in these patients as advocated by the West (JPMA 59:835; 2009).(author)
[en] Autophagy represents a cell’s response to stress. It is an evolutionarily conserved process with diversified roles. Indeed, it controls intracellular homeostasis by degradation and/or recycling intracellular metabolic material, supplies energy, provides nutrients, eliminates cytotoxic materials and damaged proteins and organelles. Moreover, autophagy is involved in several diseases. Recent evidences support a relationship between several classes of nanomaterials and autophagy perturbation, both induction and blockade, in many biological models. In fact, the autophagic mechanism represents a common cellular response to nanomaterials. On the other hand, the dynamic nature of autophagy in cancer biology is an intriguing approach for cancer therapeutics, since during tumour development and therapy, autophagy has been reported to trigger both an early cell survival and a late cell death. The use of nanomaterials in cancer treatment to deliver chemotherapeutic drugs and target tumours is well known. Recently, autophagy modulation mediated by nanomaterials has become an appealing notion in nanomedicine therapeutics, since it can be exploited as adjuvant in chemotherapy or in the development of cancer vaccines or as a potential anti-cancer agent. Herein, we summarize the effects of nanomaterials on autophagic processes in cancer, also considering the therapeutic outcome of synergism between nanomaterials and autophagy to improve existing cancer therapies