Tissue-specific regulation of BiP genes: a cis-acting regulatory domain is required for BiP promoter activity in plant meristems

The binding protein BiP is an endoplasmic reticulum (ER)-resident member of the HSP70 stress-related protein family, which is essential for the constitutive function of the ER. In addition to responding to a variety of environmental stimuli, plant BiP exhibits a tissue-specific regulation. We have isolated two soybean BiP genomic clones, designated gsBiP6 and gsBiP9, and different extensions of their 5 flanking sequences were fused to -glucuronidase (GUS) reporter gene and introduced into Nicotiana tabacum by Agrobacterium tumefaciens-mediated transformation. Transgenic plants displayed prominent GUS activity in the vascular bundles of roots and shoots as well as in regions of intense cell division, such as procambial region and apical meristems. Promoter deletion analyses identified two cis-regulatory functional domains that are important for the spatially-regulated activation of BiP expression under normal plant development. While an AT-rich enhancer-like sequence, designated cis-acting regulatory domain 1, CRD1 (–358 to –211, on gsBiP6), activated expression of the BiP minimal promoter in all organs analyzed, BiP promoter activity in meristematic tissues and phloem cells required the presence of a second activating domain, CRD2 (–211 to –80). Apparently, the CRD2 sequence also harbors negative cis-acting elements, because removal of this region caused activation of gsBiP6 promoter in parenchymatic xylem rays. These results suggest that the tissue-specific control of BiP gene expression requires a complex integration of multiple cis-acting regulatory elements on the promoter.     

Morphology of the stomach of the tropical house gecko Hemidactylus mabouia (Squamata: Gekkonidae)

Rodrigues Sartori, S. S., Nogueira, K. O. P. C., Rocha, A. S. and Neves, C. A. 2011. Morphology of the stomach of the tropical house gecko Hemidactylus mabouia (Squamata: Gekkonidae). —Acta Zoologica (Stockholm) 92 : 179–186. Hemidactylus mabouia is a common species in Brazil, which facilitates its use in research in several areas and allows display it as a benchmark for studies with reptiles. To study the morphology of the stomach of H. mabouia, we carried out anatomical, histological and histochemical analysis. The stomach of H. mabouia is ‘J’ shaped and can be divided into oral fundic (OF), aboral fundic (AF) and pyloric regions. The surface epithelium is composed of mucosecretory cells (MC) containing neutral mucins. In the lamina propria of the OF region, are large ramified tubulo‐acinar glands, which become smaller, less ramified and more tubular towards the AF region, and are simple tubular and short in the pyloric region. The fundic glands contain differentiated neck and pit. The neck is composed of MC containing neutral mucins and the pit is made of oxyntopeptic cells (OC). The OC of the OF region contained many zymogen granules, while those of the AF region contained few zymogen granules and many mitochondria, which suggests the existence of a gradient of pepsinogen and hydrochloric acid secretion. Pyloric glands consisted of MC containing neutral mucins and both argyrophil and argentaffin endocrine cells.     

Male Condition, Female Choice, and Extreme Variation in Repeated Mating in a Scaly Cricket, Ornebius aperta (Orthoptera: Gryllidae: Mogoplistinae)

Mating in the scaly cricket Ornebius aperta often includes the transfer of many spermatophores to individual females during extended copulatory interactions. We manipulated male condition in staged matings to determine whether this could explain variation in the number of repeated copulations seen across pairs. Males on a high nutrient diet were in good condition, were more likely to mate repeatedly, and transferred more spermatophores on average than low-diet males (in poor condition). High-diet males were more likely to produce a vibratory signal that increased female receptivity to repeated mating attempts. Courtship and copulatory interactions were always terminated by females, and in every case males had already formed a spermatophore when deserted by females. We conclude that variation in male repeated mating success may be due to female choice rather than an inability or unwillingness of low-diet males to produce spermatophores.     

In Silico Repositioning-Chemogenomics Strategy Identifies New Drugs with Potential Activity against Multiple Life Stages of Schistosoma mansoni

Morbidity and mortality caused by schistosomiasis are serious public health problems in developing countries. Because praziquantel is the only drug in therapeutic use, the risk of drug resistance is a concern. In the search for new schistosomicidal drugs, we performed a target-based chemogenomics screen of a dataset of 2,114 proteins to identify drugs that are approved for clinical use in humans that may be active against multiple life stages of Schistosoma mansoni. Each of these proteins was treated as a potential drug target, and its amino acid sequence was used to interrogate three databases: Therapeutic Target Database (TTD), DrugBank and STITCH. Predicted drug-target interactions were refined using a combination of approaches, including pairwise alignment, conservation state of functional regions and chemical space analysis. To validate our strategy, several drugs previously shown to be active against Schistosoma species were correctly predicted, such as clonazepam, auranofin, nifedipine, and artesunate. We were also able to identify 115 drugs that have not yet been experimentally tested against schistosomes and that require further assessment. Some examples are aprindine, gentamicin, clotrimazole, tetrabenazine, griseofulvin, and cinnarizine. In conclusion, we have developed a systematic and focused computer-aided approach to propose approved drugs that may warrant testing and/or serve as lead compounds for the design of new drugs against schistosomes.     

Cryo-electron tomography of the magnetotactic vibrio Magnetovibrio blakemorei: Insights into the biomineralization of prismatic magnetosomes

We examined the structure and biomineralization of prismatic magnetosomes in the magnetotactic marine vibrio Magnetovibrio blakemorei strain MV-1 and a non-magnetotactic mutant derived from it, using a combination of cryo-electron tomography and freeze-fracture. The vesicles enveloping the Magnetovibrio magnetosomes were elongated and detached from the cell membrane. Magnetosome crystal formation appeared to be initiated at a nucleation site on the membrane inner surface. Interestingly, while scattered filaments were observed in the surrounding cytoplasm, their association with the magnetosome chains could not be unequivocally established. Our data suggest fundamental differences between prismatic and octahedral magnetosomes in their mechanisms of nucleation and crystal growth as well as in their structural relationships with the cytoplasm and plasma membrane.     

Protective effects of acerola juice on genotoxicity induced by iron in vivo

Metal ions such as iron can induce DNA damage by inducing reactive oxygen species (ROS) and oxidative stress. Vitamin C is one of the most widely consumed antioxidants worldwide, present in many fruits and vegetables, especially inMalpighia glabra L., popularly known as acerola, native to Brazil. Acerola is considered a functional fruit due to its high antioxidant properties and phenolic contents, and therefore is consumed to prevent diseases or as adjuvant in treatment strategies. Here, the influence of ripe and unripe acerola juices on iron genotoxicity was analyzed in vivo using the comet assay and micronucleus test. The comet assay results showed that acerola juice exerted no genotoxic or antigenotoxic activity. Neither ripe nor unripe acerola juices were mutagenic to animals treated with juices, in micronucleus test. However, when compared to iron group, the pre-treatment with acerola juices exerted antimutagenic activity, decreasing significantly micronucleus mean values in bone marrow. Stage of ripeness did not influence the interaction of acerola compounds with DNA, and both ripe and unripe acerola juices exerted protective effect over DNA damage generated by iron.     

Worldwide Occurrence of Integrative Conjugative Element Encoding Multidrug Resistance Determinants in Epidemic Vibrio cholerae O1

In the last decades, there has been an increase of cholera epidemics caused by multidrug resistant strains. Particularly, the integrative and conjugative element (ICE) seems to play a major role in the emergence of multidrug resistant Vibrio cholerae. This study fully characterized, by whole genome sequencing, new ICEs carried by multidrug resistant V. cholerae O1 strains from Nigeria (2010) (ICEVchNig1) and Nepal (1994) (ICEVchNep1). The gene content and gene order of these two ICEs are the same, and identical to ICEVchInd5, ICEVchBan5 and ICEVchHai1 previously identified in multidrug resistant V. cholerae O1. This ICE is characterized by dfrA1, sul2, strAB and floR antimicrobial resistance genes, and by unique gene content in HS4 and HS5 ICE regions. Screening for ICEs, in publicly available V. cholerae genomes, revealed the occurrence and widespread distribution of this ICE among V. cholerae O1. Metagenomic analysis found segments of this ICE in marine environments far from the direct influence of the cholera epidemic. Therefore, this study revealed the epidemiology of a spatio-temporal prevalent ICE in V. cholerae O1. Its occurrence and dispersion in V. cholerae O1 strains from different continents throughout more than two decades can be indicative of its role in the fitness of the current pandemic lineage.