Effect of orlistat on the total ghrelin and leptin levels in obese patients

Obesity, characterized by hyperleptinemia and hypoghrelinemia, has become a major health problem all over the world and is associated with an increased risk of complications including insulin resistance, hypertension, dyslipidemia, diabetes mellitus and atherosclerosis. The use of the pancreatic lipase inhibitor Orlistat can help seriously overweight people to achieve and maintain weight loss. The aim of our study was to compare the serum leptin and ghrelin levels in obese subjects who take orlistat with those receiving only dietary treatment. Twenty-one obese patients and 10 control subjects participated. The obese patients were divided into two groups; one group (n=11) took orlistat (120 mg, 3 times daily) and received dietary treatment and the other (n=10) only received the dietary treatment. The study lasted twelve weeks. The concentrations of serum ghrelin, leptin, insulin and C-peptide, and routine biochemical parameters, were measured in both groups. The serum ghrelin level was higher in control (183±62 fmol/ml) than obese (59±30 fmol/ml) subjects while the plasma leptin level was lower in control (8.7±12 μg/L) than obese (36.7±19 μg/L) subjects (all p<0.001). BMI and the total blood cholesterol, LDL and triglyceride levels fell significantly after both orlistat and dietary treatment in the obese subjects (all p<0.01), and the plasma ghrelin level rose (p<0.01). The leptin level demonstrated the opposite trend in both groups but only the patients taking orlistat showed a significant change (p<0.05).Taken together, these results show that orlistat has no effect on body weight in obese subjects additional to that conferred by a non-pharmacological life-style intervention. We therefore conclude that weight lost rather than type of treatment might be more valuable in obesity.     

Cell cycle Start is coupled to entry into the yeast metabolic cycle across diverse strains and growth rates

Cells have evolved oscillators with different frequencies to coordinate periodic processes. Here we studied the interaction of two oscillators, the cell division cycle (CDC) and the yeast metabolic cycle (YMC), in budding yeast. Previous work suggested that the CDC and YMC interact to separate high oxygen consumption (HOC) from DNA replication to prevent genetic damage. To test this hypothesis, we grew diverse strains in chemostat and measured DNA replication and oxygen consumption with high temporal resolution at different growth rates. Our data showed that HOC is not strictly separated from DNA replication; rather, cell cycle Start is coupled with the initiation of HOC and catabolism of storage carbohydrates. The logic of this YMC–CDC coupling may be to ensure that DNA replication and cell division occur only when sufficient cellular energy reserves have accumulated. Our results also uncovered a quantitative relationship between CDC period and YMC period across different strains. More generally, our approach shows how studies in genetically diverse strains efficiently identify robust phenotypes and steer the experimentalist away from strain-specific idiosyncrasies.     

Desiccation survival of the eggs of the rotifer Adleta vaga (Davis, 1873)

Age at the time of drying affects the desiccation survival of the embryos of the bdelloid rotifer Adineta vaga. Although the embryos younger than 24 hours do not survive desiccation, up to 71% and 6% of the embryos at least 45 hours old survive desiccation for 2 and 10 days, respectively.     

Biochemical composition of benign thyroid cyst fluid

Although the availability of thyroid cyst fluid is easy by fineneedle aspiration, less is known about the biochemical composition of thyroid cyst fluid. The authors have, therefore, determined the biochemical composition of 18 benign thyroid cyst fluid specimens. They found that the activities of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and the concentrations of total protein, total bilirubin, and uric acid were highly increased in thyroid cyst fluid specimens when compared with normal human serum specimens. The concentrations of glucose, cholesterol, and triglycerides in cyst fluid were within normal serum limits. Selenium (Se) concentrations in most cyst fluids were low. Moreover, there was no correlation between Se and other biochemical parameters. Protein electrophoresis of cyst fluid specimens yielded high concentrations of α₁ and especially α₂ globulin fractions indicating an inflammation. The concentrations or activities of biochemical analytes were not significantly different in pure and mixed cysts. Those parameters were also not significantly different between cyst fluids of different colors. The gross appearance of the fluid and the presence of certain biochemical analytes were consistent with a hemorrhagic origin of most of the cyst fluid specimens. However, some biochemical markers indicate that autolysis or necrosis of thyroid tissue may also contribute the composition of thyroid cyst fluid. The reason for lower Se concentration in the thyroid cyst fluid may be the lower Se concentration in the Turkish population. These results also suggest that the fluid color or nature of cyst, e.g., pure or mixed cyst, is not a main determinant of biochemical composition of benign thyroid cyst fluid.     

A Highlights from MBoC Selection: Measuring fast gene dynamics in single cells with time-lapse luminescence microscopy

Time-lapse fluorescence microscopy is an important tool for measuring in vivo gene dynamics in single cells. However, fluorescent proteins are limited by slow chromophore maturation times and the cellular autofluorescence or phototoxicity that arises from light excitation. An alternative is luciferase, an enzyme that emits photons and is active upon folding. The photon flux per luciferase is significantly lower than that for fluorescent proteins. Thus time-lapse luminescence microscopy has been successfully used to track gene dynamics only in larger organisms and for slower processes, for which more total photons can be collected in one exposure. Here we tested green, yellow, and red beetle luciferases and optimized substrate conditions for in vivo luminescence. By combining time-lapse luminescence microscopy with a microfluidic device, we tracked the dynamics of cell cycle genes in single yeast with subminute exposure times over many generations. Our method was faster and in cells with much smaller volumes than previous work. Fluorescence of an optimized reporter (Venus) lagged luminescence by 15–20 min, which is consistent with its known rate of chromophore maturation in yeast. Our work demonstrates that luciferases are better than fluorescent proteins at faithfully tracking the underlying gene expression.     

Mechanical homeostasis in tissue equivalents: a review

There is substantial evidence that growth and remodeling of load bearing soft biological tissues is to a large extent controlled by mechanical factors. Mechanical homeostasis, which describes the natural tendency of such tissues to establish, maintain, or restore a preferred mechanical state, is thought to be one mechanism by which such control is achieved across multiple scales. Yet, many questions remain regarding what promotes or prevents homeostasis. Tissue equivalents, such as collagen gels seeded with living cells, have become an important tool to address these open questions under well-defined, though limited, conditions. This article briefly reviews the current state of research in this area. It summarizes, categorizes, and compares experimental observations from the literature that focus on the development of tension in tissue equivalents. It focuses primarily on uniaxial and biaxial experimental studies, which are well-suited for quantifying interactions between mechanics and biology. The article concludes with a brief discussion of key questions for future research in this field.

     

1,3‐Propanediol production from glycerol by a newly isolated Trichococcus strain

A coccal bacterium (strain ES5) was isolated from methanogenic bioreactor sludge with glycerol as the sole energy and carbon source. Strain ES5 fermented glycerol to 1,3‐propanediol as main product, and lactate, acetate and formate as minor products. The strain was phylogenetically closely related to Trichococcus flocculiformis; the rRNA gene sequence similarity was 99%. However, strain ES5 does not show the typical growth in chains of T. flocculiformis. Moreover, T. flocculiformis does not ferment glycerol. Strain ES5 used a variety of sugars for growth. With these substrates, lactate, acetate and formate were the main products, while 1,3‐propanediol was not formed. The optimum growth temperature of strain ES5 ranges from 30–37°C, but like several other Trichoccoccus strains, strain ES5 is able to grow at low temperature (< 10°C). Therefore, strain ES5 may be an appropriate catalyst for the biotechnological production of 1,3‐propanediol from glycerol at low ambient temperature.