Destruction Of Organisms Research Articles

Resistance of an intertidal oyster(Saccostrea mordax)to marine heatwaves and the implication for reef building

Marine heatwaves (MHWs) have a significant impact on intertidal bivalves and the ecosystems they sustain, causing the destruction of organisms' original habitats. Saccostrea mordax mainly inhabits the intertidal zone around the equator, exhibiting potential tolerance to high temperatures and maybe a species suitable for habitat restoration. However, an understanding about the tolerance mechanism of S. mordax to high temperatures is unclear. It is also unknown the extent to which S. mordax can tolerate repeated heatwaves of increasing intensity and frequency. Here, we simulated the effects of two scenarios of MHWs and measured the physiological and biochemical responses and gene expression spectrum of S. mordax. The predicted responses varied greatly across heatwaves, and no heatwave had a significant impact on the survival of S. mordax. Specifically, there were no statistically significant changes apparent in the standard metabolic rate and the activities of enzymes of the oyster during repeated heatwaves. S. mordax exposed to high-intensity heatwaves enhanced their standard metabolic rate to fuel essential physiological maintenance and increasing activity of SOD and expression of HSP70/90. These strategies are presumably at the expense of functions related to immunity and growth, as best exemplified by significant depressions in activities of enzymes (NaK, CaMg, T-ATP, and AKP) and expression levels of genes (Rab, eEF-2, HMGR, Rac1, SGK, Rab8, etc.). The performance status of S. mordax tends to improve by implementing a suite of less energy-costly compensatory mechanisms at various levels of biological organization when re-exposed to heatwaves. The adaptive abilities shown by S. mordax indicate that they can play a crucial role in the restoration of oyster reefs in tropical seas.

Toll-like receptor signalling in macrophages links the autophagy pathway to phagocytosis

Phagocytosis and autophagy are two ancient, highly conserved processes involved, respectively, in the removal of extracellular organisms and the destruction of organisms in the cytosol. Autophagy, for either metabolic regulation or defence, involves the formation of a double membrane called the autophagosome, which then fuses with lysosomes to degrade the contents, a process that has similarities with phagosome maturation. Toll-like-receptor (TLR) engagement activates a variety of defence mechanisms within phagocytes, including facilitation of phagosome maturation, and also engages autophagy. Therefore we speculated that TLR signalling might link these processes to enhance the function of conventional phagosomes. Here we show that a particle that engages TLRs on a murine macrophage while it is phagocytosed triggers the autophagosome marker LC3 to be rapidly recruited to the phagosome in a manner that depends on the autophagy pathway proteins ATG5 and ATG7; this process is preceded by recruitment of beclin 1 and phosphoinositide-3-OH kinase activity. Translocation of beclin 1 and LC3 to the phagosome was not associated with observable double-membrane structures characteristic of conventional autophagosomes, but was associated with phagosome fusion with lysosomes, leading to rapid acidification and enhanced killing of the ingested organism.

Diffusion of antibiotics from acrylic bone-cement in vitro

The diffusion of Fucidin, gentamicin, and clindamycin from acrylic cement was tested in an in vitro system. The activity of Fucidin was very short-lived and only against gram-positive organisms; gentamicin inhibited gram-positive and gram-negative organisms for twenty-two and eleven days respectively; clindamycin had significant action only against gram-positive organisms and retained some activity for fifty-six days. We suggest that the destruction of organisms in the tissues is more likely to be achieved by topical and intravenous administration of antibiotics during the operation than by incorporation of antibiotic in the cement.

Some General Problems Relative to the Origin of Life on Earth or Elsewhere

From the standpoint of chemistry, the following properties of life appear to be important. Living things maintain metabolic processes, that is, chemical reactions in which compounds of one kind are absorbed by living things and compounds of another kind excreted. Animals absorb compounds containing high free energy and excrete those with low free energy. Plants absorb certain compounds of low free energy, i.e., carbon dioxide, excrete compounds of high free energy, oxygen plus carbohydrates, for example, and at the same time maintain a complex metabolism in which high energy compounds are used for living processes. This dynamic metabolic process is an exceedingly important characteristic of living things. In the second place, living organisms are distinguishable from their surroundings. We would not consider an ocean in which chemical reactions of a general type such as that mentioned above were taking place as a living organism. A living organism has form and structure, and this is of a very complicated and intricate kind in the case of modern organisms. The possibility of maintaining these exceedingly complicated and highly organized bodies can only be done in the face of the degenerating processes that are predicted on the basis of natural accidents by very special arrangements. Inevitably a single living organism will degenerate or be destroyed by accident. Hence the persistence of living things in the face of this degenerative tendency can only be maintained by some other mechanism, and that mechanism is the replicative characteristic. Living organisms are able to produce additional living organisms of a fairly perfect or at least operative kind and hence make allowance for the destruction of organisms that have been damaged or degenerated. The replicative function is a necessity. The free energy for this process which enables the living organism to overcome the requirements of an increase of entropy in all processes is, of course, free energy from the sun.

Some general problems relative to the origin of life on earth or elsewhere

From the standpoint of chemistry, the following properties of life appear to be important. Living things maintain metabolic processes, that is, chemical reactions in which compounds of one kind are absorbed by living things and compounds of another kind excreted. Animals absorb compounds containing high free energy and excrete those with low free energy. Plants absorb certain compounds of low free energy, i.e., carbon dioxide, excrete compounds of high free energy, oxygen plus carbohydrates, for example, and at the same time maintain a complex metabolism in which high energy compounds are used for living processes. This dynamic metabolic process is an exceedingly important characteristic of living things. In the second place, living organisms are distinguishable from their surroundings. We would not consider an ocean in which chemical reactions of a general type such as that mentioned above were taking place as a living organism. A living organism has form and structure, and this is of a very complicated and intricate kind in the case of modern organisms. The possibility of maintaining these exceedingly complicated and highly organized bodies can only be done in the face of the degenerating processes that are predicted on the basis of natural accidents by very special arrangements. Inevitably a single living organism will degenerate or be destroyed by accident. Hence the persistence of living things in the face of this degenerative tendency can only be maintained by some other mechanism, and that mechanism is the replicative characteristic. Living organisms are able to produce additional living organisms of a fairly perfect or at least operative kind and hence make allowance for the destruction of organisms that have been damaged or degenerated. The replicative function is a necessity. The free energy for this process which enables the living organism to overcome the requirements of an increase of entropy in all processes is, of course, free energy from the sun.

The Effect of Acidity on Lactobacillus Acidophilus Cultures

Summary 1.The strains of L. acidophilus used in the experiments reported upon gave the highest plate counts at acidities of approximately 1.00 per cent. 2.There was some variation among strains, some yielding the maximum number of organisms at less than 1.00 per cent and one strain at an acidity considerably greater than 1.00 per cent. 3.A decrease in the number of organisms had taken place at an acidity of approximately 1.2 per cent in all but one strain. The strains examined seemed to differ slightly with respect to the acidity at which destruction became apparent. 4.At higher acidities of approximately 1.5, 1.6, 1.7 and 1.8 per cent, a still greater destruction of organisms took place. The acidity at which this greater destruction occurred varied with the strain. 5.The results indicated that the particular sample of each strain that gave the highest count before storage, usually gave the highest count of the series after storage at 9° or 24°C. 6.Refrigerator storage (9°C.) of typical strains of L. acidophilus resulted in a smaller loss in the numbers of organisms than did storage at 20° to 24°C, in both high and low acidities. 7.Two strains of L. acidophilus not previously reported upon also survived either refrigerator or room temperature storage for several days without any great destruction of organisms, provided that the original acidity was low. 8.It is desirable to determine the acidity at which the maximum number of organisms is secured for each strain and under the conditions that obtain. 9.The results obtained indicated that the acidity at which the maximum number of organisms was secured during incubation of a culture was an index as to the acidity at which to place cultures in refrigerator storage.