Group I introns and associated homing endonuclease genes reveals a clinal structure for <Emphasis Type="Italic">Porphyra spiralis</Emphasis> var. <Emphasis Type="Italic">amplifolia</Emphasis> (Bangiales,Rhodophyta) along the Eastern coast of South America

Background  

Group I introns are found in the nuclear small subunit ribosomal RNA gene (SSU rDNA) of some species of the genus Porphyra (Bangiales, Rhodophyta). Size polymorphisms in group I introns has been interpreted as the result of the degeneration of homing endonuclease genes (HEG) inserted in peripheral loops of intron paired elements. In this study, intron size polymorphisms were characterized for different Porphyra spiralis var. amplifolia (PSA) populations on the Southern Brazilian coast, and were used to infer genetic relationships and genetic structure of these PSA populations, in addition to cox 2-3 and rbc L-S regions. Introns of different sizes were tested qualitatively for in vitro self-splicing.     

The Effects of Periphyton, Fish and Fertilizer Dose on Biological Processes Affecting Water Quality in Earthen Fish Ponds

The potential of periphyton-based aquaculture in South Asia is under investigation in an extensive research program. This paper is a further analysis of data from four experiments carried out in that framework, to explore periphyton, fish and fertilizer dose effects on water quality. Factor analysis and ANOVA models applied to a data matrix of water quality parameters in ponds with and without artificial substrates (bamboo poles and kanchi sticks), with and without fish (filter feeders catla and rohu, with and without bottom feeder kalbaush), and with a standard or 50% increased fertilizer dose, allowed us to identify the underlying ecological processes governing this novel periphyton-based pond system, and construct conceptual graphic models of the periphyton–environment relationships observed. We clearly established that the phosphorus flow is mainly linked to phytoplankton activity in the water column and decomposition on the pond bottom, while nitrogen flow is mainly linked to autotrophic (photosynthesis) and heterotrophic (decomposition and nitrification) processes that take place in the periphyton in addition to the water column and pond bottom. Consequently, disruption of the pond bottom by bottom feeding fish primarily promoted phosphate cycling and phytoplankton, while periphyton development on the supplied substrates and fertilization mainly improved oxygen balance and nitrogen related processes developing in the water column. The use of bamboo poles led to better results than kanchi sticks, related to the greater autotrophic periphyton development on bamboo and to the larger surface of bamboo poles that facilitate fish grazing and periphyton dislodgment that in turn have a renewal effect on periphyton. Stocking bottom feeding fish produces a fertilizing effect through the food web that benefits the filter-feeding fish and that makes it unnecessary to increase the dose of inorganic and organic fertilizers applied to the ponds. Thus, the output of this analysis will help the fish farmers in resource constrained countries to improve their production in periphyton-based ponds just by choosing bamboo substrates, stocking a bottom feeder fish together with the filter feeders, and saving money on fertilizers.     

Flexibility and persistence of chimpanzee (Pan troglodytes) foraging behavior in a captive environment

As a result of environmental variability, animals may be confronted with uncertainty surrounding the presence of, or accessibility to, food resources at a given location or time. While individuals can rely on personal experience to manage this variability, the behavior of members of an individual's social group can also provide information regarding the availability or location of a food resource. The purpose of the present study was to measure how captive chimpanzees individually and collectively adjust their foraging strategies at an artificial termite mound, as the availability of resources provided by the mound varied over a number of weeks. As predicted, fishing activity at the mound was related to resource availability. However, chimpanzees continued to fish at unbaited locations on the days and weeks after a location had last contained food. Consistent with previous studies, our findings show that chimpanzees do not completely abandon previously learned habits despite learning individually and/or socially that the habit is no longer effective.     

Structural studies of an Inv (1, −2) kappa light chain

A Bence Jones protein with phenotype Inv (1, –2) was isolated from the urine of a patient with multiple myeloma. Inv typing of the patient's relatives established the presence of anInv ¹ allele in the kindred, and that the patient's genotype wasInv ¹/Inv ³. Hence, the absence of Inv (2) in the Bence Jones protein was shown to be genetic and not an artifact caused by the disease. The tryptic peptide-containing residues 191 through 194 were isolated and shown to be composed of Leu, Tyr, Ala, Cys, with Leu at the amino end. Hence, the residue at 191 is the same as that present in Inv (1, 2) Bence Jones proteins. More detailed study of the tryptic peptides established that residue 153 is Val rather than Ala as in all other K chains thus far studied. The primary sequence: Ala¹⁵³, Leu¹⁹¹ determines Inv (1, 2); Ala¹⁵³, Val¹⁹¹ determines Inv (3); and Val¹⁵³, Leu¹⁹¹ determines Inv (1). The Val¹⁵³, Val¹⁹¹ sequence has not been observed. It may correspond to Inv (–). These data are strikingly similar to the data for the Kern and Oz isotypes (changes at 154 and 191, respectively) in the chain. As in the case of theK chain, only three of the four possible combinations have been observed. The implications of this parallelism and of crystallographic findings on chains, reported by others, are discussed.     

Therapeutic siRNA silencing in inflammatory monocytes in mice

Excessive and prolonged activity of inflammatory monocytes is a hallmark of many diseases with an inflammatory component. In such conditions, precise targeting of these cells could be therapeutically beneficial while sparing many essential functions of the innate immune system, thus limiting unwanted effects. Inflammatory monocytes-but not the noninflammatory subset-depend on the chemokine receptor CCR2 for localization to injured tissue. Here we present an optimized lipid nanoparticle and a CCR2-silencing short interfering RNA that, when administered systemically in mice, show rapid blood clearance, accumulate in spleen and bone marrow, and localize to monocytes. Efficient degradation of CCR2 mRNA in monocytes prevents their accumulation in sites of inflammation. Specifically, the treatment attenuates their number in atherosclerotic plaques, reduces infarct size after coronary artery occlusion, prolongs normoglycemia in diabetic mice after pancreatic islet transplantation, and results in reduced tumor volumes and lower numbers of tumor-associated macrophages.