Deletions Induced by Heat Treatment of E. COLI K12 Lysogenic for λ Prophages

We have investigated the production of prophage deletions in heat-induced λ lysogens of E. coli K12. Our results are indicative of a direct action of the heat-induced prophage in producing deletions. The temperature of 40° used for the experiments may be critical to prove this effect. The phage function involved in deletion formation is not known.     

Impact of HIV-1 subtype and antiretroviral therapy on protease and reverse transcriptase genotype: results of a global collaboration

BackgroundThe genetic differences among HIV-1 subtypes may be critical to clinical management and drug resistance surveillance as antiretroviral treatment is expanded to regions of the world where diverse non-subtype-B viruses predominate.ConclusionGlobal surveillance and genotypic assessment of drug resistance should focus primarily on the known subtype B drug-resistance mutations.     

Secreted phosphatase activity induced by dimethyl sulfoxide in Herpetomonas samuelpessoai

The secreted form of mouse meprin A is a homooligomer of meprin alpha subunits that contain a prosequence, a catalytic domain, and three domains designated as MAM (meprin, A5 protein, receptor protein-tyrosine phosphatase mu), MATH (meprin and TRAF homology), and AM (AfterMath). Previous studies indicated that wild-type mouse meprin alpha is predominantly a secreted protein, while the MAM deletion mutant (DeltaMAM) is degraded intracellularly. The work herein indicates that the DeltaMAM mutant is ubiquitinated and degraded via the proteasomal pathway. Both wild-type meprin alpha and the DeltaMAM mutant interact with the molecular chaperones calnexin and calreticulin in the endoplasmic reticulum. The interactions of the chaperones with the DeltaMAM mutant were significantly prolonged in the presence of lactacystin, a specific inhibitor of the proteasome, whereas those with the wild type were not affected by this inhibitor. Trimming of the Asn-linked core oligosaccharides of meprin subunits was required for interactions with the chaperones. The data indicated that folding of the wild-type protein was accelerated by chaperones, whereas the rate of dimerization was unaffected. Thus, calnexin and calreticulin are intimately involved in the correct folding and transport of meprin to the plasma membrane, as well as in retrograde transport of the DeltaMAM mutant to the ubiquitin-dependent proteasomal degradative pathway in the cytosol.     

Free l-amino acids and d-aspartate content in the nervous system of Cephalopoda. A comparative study

We have determined the content of free l-amino acids and d-aspartate in the nervous tissue of three representative cephalopods: Sepia officinalis, Octopus vulgaris, and Loligo vulgaris, and the optic lobes of adult and embryo Sepia officinalis. Taurine is the most abundant amino acid in the cephalopod nervous tissue. Its content amounts to more than 50% of the total free amino acids. The other most concentrated amino acids are Glu, Ala, Asp, and GABA. High concentrations of d-aspartate were found in the nervous tissue of all cephalopods examined (7–12 μmol/g wet tissue) which represents 50–80% of the total aspartate (d + l), depending on the animal. Among the various regions of the brain of Octopus vulgaris, d-aspartate was found to be evenly distributed in the various regions of the brain. In nerve tissue of Sepia officinalis, there is no significant difference in the pattern of free l-amino acids, in particular of the d-aspartate concentration, between adults and embryos, except for GABA, Gly, His and Thr. This suggests that d-aspartate in nerve tissue of the Cephalopoda is of endogenous origin and not a product of accumulation from exogenous sources. From a comparative study of the content of d-aspartate in the nervous tissue of different animals, we found that protostomia contain a significantly higher amount than deuterostomia. Thus, d-aspartate could be a criterion to distinguish the protostomia phyla from the deuterostomia phyla.     

Analysis of mesophyll conductance in five understory herbaceous species

Mesophyll conductance (gm) has received over time much less attention than stomatal conductance (gs), although it affects leaf photosynthesis to about the same extent as stomatal conductance does. The objective of this study was to analyze the gm trend in five understory herbaceous species growing in a close-canopy forest in the north-west of Italy. In particular, three of analyzed species were monocots: Carex brizoides Lam., Carex pilosa Scop., and Oplismenus undulatifolius P. Beauv and the others dicots species: Circaea lutetiana L., and Pulmonaria officinalis Ced. The results showed, on one hand, the absence of correlation between gm and the considered environmental variables in the forest understory (i.e. air temperature, photosynthetic photon flux density and carbon dioxide concentration). Moreover, we carried out a principal component analysis considering all the analyzed morphological and physiological variables for the five species. The following correlation between the first component, related to the leaf mass per unit of leaf area and the leaf tissue density, and gm seem to suggest a key role of the leaf structural features in determining gm variations across the five species.     

A new Brazilian Passiflora leafminer: Spinivalva gaucha,gen. n., sp. n. (Lepidoptera,Gracillariidae, Gracillariinae), the first gracillariid without a sap-feeding instar

Male, female, pupa, larva and egg of a new genus and species of Gracillariidae (Gracillariinae), Spinivalva gaucha Moreira and Vargas from southern Brazil are described and illustrated with the aid of optical and scanning electron microscopy. A preliminary analysis of mitochondrial DNA sequences including members of related lineages is also provided. The immature stages are associated with Passiflora actinia, Passiflora misera and Passiflora suberosa (Passifloraceae), and build mines on the adaxial leaf surface. Initially the mines are serpentine in shape, but later in larval ontogeny become a blotch type. Although the larvae are hypermetamorphic as in other Gracillariidae, there is no sap-feeding instar in Spinivalva gaucha; the larva feeds on the palisade parenchyma, thus producing granular frass during all instars. Pupation occurs outside the mine; prior to pupating, the larva excretes numerous bubbles that are placed in rows on the lateral margins of the cocoon external surface. This is the second genus of gracillariid moth described for the Atlantic Rain Forest, and the second gracillariid species known to be associated with Passifloraceae.     

Age structure and multi-model growth estimation of longnose stingray Hypanus guttatus (Dasyatidae: Myliobatoidei) from north-east Brazil

We collected 729 Hypanus guttatus from the northern coast of the state of Rio Grande do Norte (RN), of which 196 were used to estimate age and growth. Ninety-five were male (12.7 to 57.0 cm disc width; W_D) and 101 were female (13.0 to 88.5 cm W_D); females were significantly larger than males. Cross sections of vertebrae showed band-pairs ranging from 0 to > 14 in females and from 0 to 9 in males. New-borns presented an opaque edge at birth in vertebrae without a birthmark. The average percentage of error (APE; %E) for the entire sample provided evidence that ages were repeatable. The mean monthly marginal increment (I_M) indicates annual band-pair formation from August to November. The annual cycle model for one band-pair deposition provided the best fit to data based on the AIC, with peaks between August and October, similar to that found in the I_M analysis, suggesting an annual formation pattern. A multi-model approach that included four models based on the observed mean W_D at age indicated a modified von Bertalanffy growth model as the best for describing the species growth: W₀ (W_D at birth) = 14.6 cm for both sexes; females W_∞ = 98.61 cm (95% CI = 87.34–114.61 cm); k = 0.112 year⁻¹ (CI = 0.086–0.148 year⁻¹); males W_∞ = 60.22 cm (CI = 55.66–65.35 cm); k = 0.219 year⁻¹ (CI = 0.185–0.276 year⁻¹). The age-at-maturity in males and females is 5 years and 7 years, respectively. The age composition shows that most (84%) specimens were aged 0 to 2 years. The information provided here is essential for analytical assessments of H. guttatus, which is subject to significant fishing pressure mainly on new-borns and juveniles.