Microbiological quality of tomato (<i>Solanum lycopersicum</i> L.) produced under greenhouse conditions in five Municipalities of the State of Mexico

The aim of the current research was to determine tomato (Solanum lycopersicum L.) microbiological quality produced under greenhouse conditions in 5 municipalities of the State of Mexico. Studies were conducted during the 2013 production cycle to know the risks and apply prevention strategies prior to its consumption. A microbiological analysis of samples of irrigation water, soil and 100 tomato fruits variety cid was performed to determine Aerobic Mesophiles, Total Coliforms and Fecal Coliforms. The methodology used were those according to the Official Mexican Standards NOM- 109-SSA1-1994, NOM-110-SSA1-1994, NOM-092-SSA1-1994, NOM-113-SSA1-1994, and the Regulations of the National French Organization for Standardization (AFNOR) NF V08-60, and NOM-093-SSA1-1994, which establish the allowable limits for the study microorganisms. The results showed a zero level of pollution in water and soil samples. For fruits, levels of Aerobic Mesophilic were within the maximum limits permitted by the standards. The municipality of Texcaltitlan showed the highest average for these microorganisms (10083.80 CFU/mL). Huixquilucan showed 2266.84 CFU/mL for Total Coliforms. For Fecal Coliforms, municipalities of Coatepec and Texcaltitlan exceeded the allowed limit.     

Insights into the substrate specificity of plant peptide deformylase, an essential enzyme with potential for the development of novel biotechnology applications in agriculture

CD151, a member of the tetraspanin family of proteins, forms a stable complex with integrin alpha 3 beta 1 and regulates integrin-mediated cell-substrate adhesion. However, the molecular basis of the stable association of CD151 with integrin alpha 3 beta 1 remains poorly understood. In the present study, we show that a panel of anti-human CD151 mAbs (monoclonal antibodies) could be divided into three groups on the basis of their abilities to co-immunoprecipitate integrin alpha 3: Group-1 mAbs were devoid of sufficient activities to co-precipitate integrin alpha 3 under both low- and high-stringency detergent conditions; Group-2 mAbs co-precipitated integrin alpha 3 under low-stringency conditions; and Group-3 mAbs exhibited strong co-precipitating activities under both conditions. Group-1 mAbs in particular exhibited increased reactivity toward integrin alpha 3 beta 1-unbound CD151, indicating that the binding sites for Group-1 mAbs are partly blocked by bound integrin alpha 3 beta 1. Epitope mapping using a series of CD151 mutants with substitutions at amino acid residues that are not conserved between human and mouse CD151 revealed that Gly(176)/Gly(177), Leu(191) and Gln(194) comprise epitopes characteristic of Group-1 mAbs. Replacement of short peptide segments, each containing one of these epitopes, with those of other tetraspanins lacking stable interactions with integrin alpha 3 beta 1 demonstrated that the segment from Cys(185) to Cys(192), including Leu(191), was involved in the stable association of CD151 with integrin alpha 3 beta 1, as was the Gln(194)-containing QRD peptide. Taken together these results indicate that two consecutive segments including two Group-1 epitopes, Leu(191) and Gln(194), comprise an interface between CD151 and integrin alpha 3 beta 1, and, along with the epitope including Gly(176)/Gly(177), are concealed by bound integrin.     

Corrected sequence of the bacteriophage p22 genome

We report the first accurate genome sequence for bacteriophage P22, correcting a 0.14% error rate in previously determined sequences. DNA sequencing technology is now good enough that genomes of important model systems like P22 can be sequenced with essentially 100% accuracy with minimal investment of time and resources.     

Dexamethasone-induced changes in lung function are not prevented by concomitant treatment with retinoic acid

Alveolarization is impaired in rats treated with dexamethasone (Dex) on postnatal days 4-13, but concomitant treatment with all-trans retinoic acid (RA) increases alveolar number. To determine whether morphological changes induced by Dex and/or RA predict changes in lung function at 1 mo, we assessed resting breathing parameters, dynamic compliance, ventilation required to maintain O(2) saturation at > or = 90%, and pressure-volume curves of air-filled lungs. During resting breathing, mean tidal volume per gram was greater in Dex + RA-treated rats than in controls (P < 0.05). Dynamic compliance was also greater in Dex- and Dex + RA-treated rats than in controls or RA-treated rats (P < 0.02). In Dex- and Dex + RA-treated rats, we observed increased hysteresis ratios (P < or = 0.006), air trapping (P < 0.05), and lung volumes at 5 and 13.5 cmH(2)O pressure (P < 0.001) and decreased elastic recoil (P < 0.007). The effect of Dex on elastic recoil was greater in female than in male rats (P = 0.006). Despite impaired septation, O(2) saturation was not compromised in Dex- or Dex + RA-treated rats. Thus lung function changes induced by Dex treatment during alveolarization were not prevented by concomitant treatment with RA.     

Cryobanking of viable biomaterials: implementation of new strategies for conservation purposes

Cryobanking, the freezing of biological specimens to maintain their integrity for a variety of anticipated and unanticipated uses, offers unique opportunities to advance the basic knowledge of biological systems and their evolution. Notably, cryobanking provides a crucial opportunity to support conservation efforts for endangered species. Historically, cryobanking has been developed mostly in response to human economic and medical needs — these needs must now be extended to biodiversity conservation. Reproduction technologies utilizing cryobanked gametes, embryos and somatic cells are already vital components of endangered species recovery efforts. Advances in modern biological research (e.g. stem cell research, genomics and proteomics) are already drawing heavily on cryobanked specimens, and future needs are anticipated to be immense. The challenges of developing and applying cryobanking for a broader diversity of species were addressed at an international conference held at Trier University (Germany) in June 2008. However, the magnitude of the potential benefits of cryobanking stood in stark contrast to the lack of substantial resources available for this area of strategic interest for biological science — and society at large. The meeting at Trier established a foundation for a strong global incentive to cryobank threatened species. The establishment of an Amphibian Ark cryobanking programme offers the first opportunity for global cooperation to achieve the cryobanking of the threatened species from an entire vertebrate class.     

Direct and correlated responses to artificial selection on lipid and glycogen contents in Drosophila melanogaster

A large outbred population of Drosophila melanogaster was subjected to artificial selection on lipid and glycogen storage. In three separate experiments, two replicates underwent sib selection for both increased and decreased storage. In the first study, flies were selected on the basis of total triacylglycerol for ten generations. This experiment resulted in no significant direct response, but there was a significant change in total body weight, underscoring the importance of concern for the allometric relationship between body weight and lipid content. In the second study, selection was performed for 15 generations on the percentage of body composition that was triacylglycerol. A significant direct response was obtained, and the two replicates revealed heritability estimates of 0.40 and 0.43. The third study selected glycogen content for 15 generations, and produced a significant response with heritabilities of 0.25 and 0.31. A series of 12 biochemical and enzyme kinetic traits was examined at five generation intervals in all experiments, and a number of correlated responses were detected. The results are interpreted with respect to the evolutionary constraints on energy storage evolution and the genetic basis of the allometric relationship between body weight and fat content.