Morphometric study of bone marrow in chronic lymphocytic leukemia

A morphometric study utilizing the point counting method was carried out on bone marrow biopsies of 44 patients with chronic lymphocytic leukemia (CLL) in order to correlate the objective volume of the lymphocytic infiltration with the histologic patterns (nodular, interstitial, mixed and diffuse) and the clinical stages (A, B and C). The prognostic significance of isolated lymphocytic tumor cell burden was also analyzed. The results suggest that there is a significant correlation between the amount of tumoral lymphoid tissue (VL greater than 60% versus VL less than 60%) and the interstitial and diffuse histologic patterns, as well as with the clinical stages A and C. However, the lymphoid burden did not correlate with the nodular and mixed patterns, nor with the clinical stage B. When patients with VL greater than 60% were compared with those with VL less than 60%, the difference in cumulative survival rates was not significant after the fourth year.     

Bolivian Altiplano streams with low richness of macroinvertebrates and large diel fluctuations in temperature and dissolved oxygen

We sampled benthic macroinvertebrates and recorded oxygen and temperature regime during 2-day periods in 12 stream sites at an altitude of 3,800–4,000 m a.s.l. on the Bolivian Altiplano, during low flow conditions at the end of the dry season. Eight of the sites were relatively unpolluted, while the remaining four sites were affected by domestic/industrial sewage. Compared to other Andean streams, the fauna was poor with a total of 28 and a mean of 11 taxa (mostly families) in the unpolluted sites. The entire EPT group was represented by just five families. Of these, only Baetidae and Hydroptilidae were common. At all sites, the dominant taxa were found among just four taxa (Elmidae, Chironomidae, Oligocheata and Hyallelidae). Mean water temperature was 12.9°C, while mean diel amplitude was 13.4°C and the maximum range 17.4°C. Ten richness and biotic indices were used to analyse for effects of temperature and oxygen on the fauna. Most measures of fauna richness were negatively correlated with mean and max temperature (even excluding the four polluted sites), while biotic indices were mostly uncorrelated with temperature. Thus, the large fluctuations in temperature seemed to exclude taxa, thereby reducing overall diversity of Altiplano streams. Oxygen saturation also varied considerably, with a mean diel range of 48% and a maximum range of 93%. Richness measures were uncorrelated with oxygen %, while all biotic indices were positively correlated with either mean or min oxygen %. Most measures of faunal composition showed a marked shift at levels of 10–30% min oxygen saturation. Earlier studies of high Andean streams in Ecuador have shown a major shift in faunal composition at 50–60% oxygen saturation. The fauna in the Altiplano streams may be adapted to the large fluctuations in oxygen saturation, and therefore more robust towards low oxygen saturations. The implications for biotic assessment of Altiplano streams are discussed.     

An Ancient Fingerprint Indicates the Common Ancestry of Rossmann-Fold Enzymes Utilizing Different Ribose-Based Cofactors

Nucleoside-based cofactors are presumed to have preceded proteins. The Rossmann fold is one of the most ancient and functionally diverse protein folds, and most Rossmann enzymes utilize nucleoside-based cofactors. We analyzed an omnipresent Rossmann ribose-binding interaction: a carboxylate side chain at the tip of the second β-strand (β2-Asp/Glu). We identified a canonical motif, defined by the β2-topology and unique geometry. The latter relates to the interaction being bidentate (both ribose hydroxyls interacting with the carboxylate oxygens), to the angle between the carboxylate and the ribose, and to the ribose’s ring configuration. We found that this canonical motif exhibits hallmarks of divergence rather than convergence. It is uniquely found in Rossmann enzymes that use different cofactors, primarily SAM (S-adenosyl methionine), NAD (nicotinamide adenine dinucleotide), and FAD (flavin adenine dinucleotide). Ribose-carboxylate bidentate interactions in other folds are not only rare but also have a different topology and geometry. We further show that the canonical geometry is not dictated by a physical constraint—geometries found in noncanonical interactions have similar calculated bond energies. Overall, these data indicate the divergence of several major Rossmann-fold enzyme classes, with different cofactors and catalytic chemistries, from a common pre-LUCA (last universal common ancestor) ancestor that possessed the β2-Asp/Glu motif.     

Nucleoid-associated Rok differentially affects chromosomal transformation on Bacillus subtilis recombination-deficient cells

Rok, a Bacillus subtilis nucleoid-associated protein (NAP), negatively regulates competence development and silences xenogeneic genes. We show that rok inactivation increases rpoB482 natural intraspecies chromosomal transformation (CT) and plasmid transformation to a different extent. In ΔaddAB, ΔrecO, recF15, ΔrecU, ΔruvAB or rec⁺ cells intraspecies CT significantly increases, but the ΔrecD2 mutation reduces, and the ΔrecX, ΔradA or ΔdprA mutation further decreases CT in the Δrok context when compared to rok⁺ cells. These observations support the idea that rok inactivation, by altering the topology of the recipient DNA, differentially affects the integration of homologous DNA in rec-deficient strains, and in minor extent the competent subpopulation size. The impairment of other NAP (Hbsu or LrpC) also increased intra- and interspecies CT (nonself-DNA, ~8% nucleotide sequence divergence) in rec⁺ cells, but differentially reduced both types of CTs in certain rec-deficient strains. We describe that rok inactivation significantly stimulates intra and interspecies CT but differentially reduces them in transformation-deficient cells, perhaps by altering the nucleoid architecture. We extend the observation to other NAPs (Hbsu, LrpC).     

Review of the life history,fisheries, and stock assessment for small tunas in the Atlantic Ocean

Reviews in Fish Biology and Fisheries - Despite being an important source of wealth and food security for many countries, most of the small tuna stocks in the Atlantic Ocean and Mediterranean Sea...     

Pre-release packing and chilling reduce host-searching ability of the parasitoid Diachasmimorpha longicaudata used in the augmentative control of tephritid flies

Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) is a solitary parasitoid used in augmentative releases to control Tephritidae (Diptera) fruit flies of economic importance. Pre-release process includes packing adult parasitoids in cages at high densities and expose them to a temperature of 2 ± 2 °C during 105 min. In this process, females’ antennae may be damaged resulting in a reduction in their host-searching ability and fecundity. Here we measured, for five consecutive days after chilling, the searching ability and fecundity of parasitoids with damaged (D) and undamaged (ND) antennae compared with parasitoids that were not chilled. Female individual responses to fruit infested by Anastrepha spp. was determined in an olfactometer. Latency in the response and latency in making a choice were recorded. Additionally, groups of 30 females were used to measure their ability to find hosts in infested fruit in the laboratory. Fecundity was determined by using artificial oviposition units with Anastrepha ludens (Loew) larvae. In the olfactometer test, ND had lower response than control females during the 1st and 2nd days after chilling. However, no difference in the response was observed between ND and D and the control females on the 5th day. Additionally, chilled females showed a longer latency of response to infested fruit than females of the control treatment when tested in groups. However, after a 24–48 h period, no difference between D and ND and control females was observed. Our results showed similar searching ability and fecundity among parasitoids of the three tested conditions at individual and at group levels. We conclude that pre-release chilling reduces female searching ability only for the first 1–2 days after chilling.