Proliferation of fetal brown adipocyte primary cultures: Relationship with the genetic expression of glucose 6 phosphate dehydrogenase

Fetal brown adipocyte primary cultures increase DNA synthesis; cell number; and DNA, RNA, and protein contents in response to 10% fetal calf serum, IGF-I, and EGF plus vasopressin plus bombesin when added for 64 h to quiescent cells. IGF-I is a complete growth factor in this system while EGF needs the presence of vasopressin plus bombesin for its maximal proliferative effects. These mitogens induce the genetic expression of G6P dehydrogenase, increasing its mRNA content as well as its specific activity and amount of immunoreactive protein. The presence of cAMP elevating agents prevents the stimulatory effect of EGF plus vasopressin plus bombesin on DNA synthesis, cell number, and DNA content as well as on the induction of G6P dehydrogenase expression. Thus, changes on the proliferative state of these cells are associated with the level of expression of G6P dehydrogenase.     

Seasonal reproduction in Mexican cottontail rabbits<Emphasis Type="Italic">Sylvilagus cunicularius</Emphasis> in La Malinche National Park,central Mexico

Mexico has the largest number of leporid species in the world but most have been little studied. The endemic Mexican cottontailSylvilagus cunicularius (Waterhouse, 1848) is the largest Mexican rabbit, and although not in danger of extinction, it is increasingly threatened. Since little is known about its annual pattern of reproduction, we studied this species in La Malinche National Park, central Mexico, whereS. cunicularius is still common. For 7 years we trapped and marked 157 different individuals (plus 59, sometimes multiple, re-captures), determining across the year the percent of adult females that were reproductively active, the number of juveniles as a percent of total captures, and the percent of males with scrotal testes. Reproductively active females were present throughout the year but with a notable peak from March to October, juveniles were present throughout the year but with a peak from September to December, and adult males had scrotal testes throughout the year with no seasonal change in testis length. Onset of the breeding season coincided with increasing day length and temperature, and births with high rainfall. Thus, in central MexicoS. cunicularius breeds throughout the year but particularly during the warmer, wetter summer months. We therefore recommend that hunting only be permitted from November to February.     

Fluorescent reporter systems for tracking probiotic lactic acid bacteria and bifidobacteria

In the last two decades, there has been increasing evidence supporting the role of the intestinal microbiota in health and disease, as well as the use of probiotics to modulate its activity and composition. Probiotic bacteria selected for commercial use in foods, mostly lactic acid bacteria and bifidobacteria, must survive in sufficient numbers during the manufacturing process, storage, and passage through the gastro-intestinal tract. They have several modes of action and it is crucial to unravel the mechanisms underlying their postulated beneficial effects. To track their survival and persistence, and to analyse their interaction with the gastro-intestinal epithelia it is essential to discriminate probiotic strains from endogenous microbiota. Fluorescent reporter proteins are relevant tools that can be exploited as a non-invasive marker system for in vivo real-time imaging in complex ecosystems as well as in vitro fluorescence labelling. Oxygen is required for many of these reporter proteins to fluoresce, which is a major drawback in anoxic environments. However, some new fluorescent proteins are able to overcome the potential problems caused by oxygen limitations. The current available approaches and the benefits/disadvantages of using reporter vectors containing fluorescent proteins for labelling of bacterial probiotic species commonly used in food are addressed.     

High bioreactor production and emulsifying activity of an unusual exopolymer by Chromohalobacter canadensis 28

Unusual composition of an exopolymer (EP) from an obligate halophilic bacterium Chromohalobacter canadensis 28 has triggered an interest in development of an effective bioreactor process for its production. Its synthesis was investigated in 2‐L bioreactor at agitation speeds at interval 600‐1000 rpm, at a constant air flow rate of 0.5 vvm; aeration rates of 0.5, 1.0, and 1.5 vvm were tested at constant agitation rate of 900 rpm. EP production was affected by both, agitation and aeration. As a result twofold increase of EP yield was observed and additionally increased up to 3.08 mg/mL in a presence of surfactants. For effective scale‐up of bioreactors mass transfer parameters were estimated and lowest values of K_La obtained for the highest productivity fermentation was established. Emulsification activity of EP exceeded that of trade hydrocolloids xanthan, guar gum, and cellulose. A good synergism between EP and commercial cellulose proved its potential exploration as an enhancer of emulsifying properties of trade emulsions. A pronounced lipophilic effect of EP was established toward olive oil and liquid paraffin. Cultivation of human keratinocyte cells (HaCaT) with crude EP and purified γ‐polyglutamic acid (PGA) showed higher viability than control group.     

Camphene,a Plant Derived Monoterpene,Exerts Its Hypolipidemic Action by Affecting SREBP-1 and MTP Expression

The control of hyperlipidemia plays a central role in cardiovascular disease. Previously, we have shown that camphene, a constituent of mastic gum oil, lowers cholesterol and triglycerides (TG) in the plasma of hyperlipidemic rats without affecting HMG-CoA reductase activity, suggesting that its hypocholesterolemic and hypotriglyceridemic effects are associated with a mechanism of action different than that of statins. In the present study, we examine the mechanism by which camphene exerts its hypolipidemic action. We evaluated the effect of camphene on the de novo synthesis of cholesterol and TG from [¹⁴C]-acetate in HepG2 cells, along with the statin mevinolin. Camphene inhibited the biosynthesis of cholesterol in a concentration-dependent manner, and a maximal inhibition of 39% was observed at 100 μM while mevinolin nearly abolished cholesterol biosynthesis. Moreover, treatment with camphene reduced TG by 34% and increased apolipoprotein AI expression. In contrast, mevinolin increased TG by 26% and had a modest effect on apolipoprotein AI expression. To evaluate the mode of action of camphene, we examined its effects on the expression of SREBP-1, which affects TG biosynthesis and SREBP-2, which mostly affects sterol synthesis. Interestingly, camphene increased the nuclear translocation of the mature form of SREBP-1 while mevinolin was found to increase the amount of the mature form of SREBP-2. The effect of camphene is most likely regulated through SREBP-1 by affecting MTP levels in response to a decrease in the intracellular cholesterol. We propose that camphene upregulates SREBP-1 expression and MTP inhibition is likely to be a probable mechanism whereby camphene exerts its hypolipidemic effect.     

Demography,density, and survival of an endemic and near threatened cottontail<Emphasis Type="Italic">Sylvilagus cunicularius</Emphasis> in central Mexico

A 3-year live trapping investigation was carried out in a temperate forest in central Tlaxcala, México from 2002 to 2004. During a total of 504 trap nights, 87Silvilagus cunicularius Waterhouse, 1848 individuals were captured and marked, and age-specific survival models using demographic parameters were tested using the JOLLYAGE program. We evaluated population density of this species over a 1-year period. The age structure of the population varied among years, and the proportion of adults was relatively constant among years, whereas the proportion of juvenile showed high fluctuations. The sex ratio of juveniles that were recaptured as adults, did not differ from unity neither did the sex ratio for adults. We found no sex bias among cottontails during all 3 years of the study. When data for both sexes were combined, mean survival probability of juveniles was lower than that of adults. Although our line transect counts showed a mean density of 27 ± 5.4 individuals per km², the obtained results from trapping suggests that this species is low in abundance at La Malinche. Further studies are needed to evaluate demographical aspects of this species at different protected and unprotected areas to obtain robust information about their status.     

Morphological and molecular studies of <Emphasis Type="Italic">Hyphodermella</Emphasis> in the Western Mediterranean area

The genus Hyphodermella was studied based on material from the western Mediterranean area (France, Italy, Spain, Portugal and Morocco) where the following three species have been recognized: H. corrugata (Fr.) J. Erikss. & Ryvarden, widely distributed, H. densa Melo & Hjortstam, only known from Portugal, and H. rosae (Bres.) Nakasone described from Italy. Twenty-one new ITS nrDNA sequences from these species, including the holotype collection of H. rosae and the paratype of H. densa, were aligned with one obtained from GenBank. The molecular results show that these collections are distributed in two highly supported monophyletic clades: one corresponds to H. corrugata, and the other one with H. densa and H. rosae collections. Morphological studies, including the type collections of the three taxa, show significant differences between the clades if we take into account the size of basidia and spores. The present study confirms H. corrugata as an independent species of H. rosae and H. densa, and that H. densa and H. rosae are conspecific; consequently, H. densa is a synonym of H. rosae. This last species is widely distributed in the Mediterranean area (France, Italy, Spain and Portugal) and as frequent as H. corrugata. Comments are offered on sequencing the barcode from types and well-annotated specimens.     

Triplex‐Stabilizing Properties of Parallel Clamps Carrying LNA Derivatives at the Hoogsteen Strand

DNA Parallel clamps with a polypurine strand linked to a polypyrimidine Hoogsteen strand containing locked nucleic acids bind their corresponding polypyrimidine targets with high affinity.     

Thyroid hormonal axis regulates protein C anticoagulation pathway in rats

Effects of the hormones of the hypothalamic-pituitary-thyroid axis on some basic parameters of the activity of protein C anticoagulation pathway in rats are studied. Thyrotropin-releasing hormone (0.06 mg/kg body mass), thyrotropin (1 IU/kg), triiodothyronine (T3) (0.08 mg/kg), thyroxine (T4) (0.08 mg/kg), administered subcutaneously for three consecutive days on four different groups of rats increased significantly activated protein C, free protein S and protein S activity, and reduced the soluble endothelial protein C receptor. Protein C antigen and total protein S were significantly elevated only by thyrotropin-releasing hormone and thyroid-stimulating hormone, but they were not affected by T3 and T4 treatment. The data indicate the hypothalamic-pituitary-thyroid axis is involved in the regulation of the protein C anticoagulation pathway in rats by activation of this system, suggesting a tendency of hypocoagulability.