B-chromosomes in the myrmicine ant,Leptothorax spinosior

B-chromosomes of ants (Formicidae, Hymenoptera) were observed for the first time in the myrmicine ant Leptothorax spinosior using an improved squash technique. The B-chromosomes are minute heterochromatic metacentrics resembling isochromosomes. They were found almost entirely in male germ cells and exhibited intra- and inter-individual numerical variation, with numbers ranging between 1 and 12. B-chromosomes were rarely found in female germ cells or somatic cells (cerebral ganglion cells) of all castes, which suggests that the B-chromosomes are unstable in those cells. The number of heterochromatic bodies in interphase nuclei corresponds well to that of metaphase B-chromosomes. The analysis of heterochromatic bodies in female cells suggested that B-chromosomes are maintained in oocytes but almost totally eliminated from nurse cells.     

A propos de l'article ‘The B-chromosomes of Locusta migratoria I. Detection of negative correlation between mean chiasma frequency and the rate of accumulation of the B's; a reanalysis of the available data about the transmission of these B-chromosomes’, par. J. Cabrero,E. Viseras et J. P. M. Camacho

Comment on the article ‘The B-chromosomes of Locusta migratoria I. Detection of negative correlation between mean chiasma frequency and the rate of accumulation of the B's; a reanalysis of the available data about the transmission of these B-chromosomes’ — Some critical remarks on the said article (published in Genetica 64: 155–164, 1984) are presented.     

Permeability of isolated rat hepatocyte plasma membranes for molecules of dimethyl sulfoxide

We have studied permeability of isolated rat hepatocyte membranes for molecules of dimethyl sulfoxide (DMSO) at different hypertonicity of a cryoprotective medium. The permeability coefficient of hepatocyte membranes k ₁ for DMSO molecules was shown to be the differential function of osmotic pressure between a cell and an extracellular medium. Ten-fold augmentation of DMSO concentration in the cryoprotective medium causes the decrease of permeability coefficients k ₁ probably associated with the increased viscosity in membrane-adjacent liquid layers as well as partial limitations appeared as a result of change in cell membrane shape after hepatocyte dehydration. We have found out that in aqueous solutions of NaCl (2246 mOsm/L) and DMSO (2250 mOsm/L) the filtration coefficient L _p in the presence of a penetrating cryoprotectant (L _pDMSO = (4.45 ± 0.04) · 10^?14 m³/Ns) is 3 orders lower compared to the case with electrolyte (L _pNaCl = (2.25 ± 0.25) · 10^?11 m³/Ns). This phenomenon is stipulated by the cross impact of flows of a cryoprotectant and water at the stage of cell dehydration. Pronounced lipophilicity of DMSO, geometric parameters of its molecule as well as the presence of large aqueous pores in rat hepatocyte membranes allow of suggesting the availability of two ways of penetrating this cryoprotectant into the cells by non-specific diffusion through membrane lipid areas and hydrophilic channels.     

Shoot regeneration from mesophyll protoplasts and leaf explants of Rehmannia glutinosa

Mesophyll protoplasts obtained from leaves of shoot cultures of Rehmannia glutinosa were cultured in Murashige and Skoog (1962) liquid or liquid-over-agar medium containing 2.0 mg L^?1 naphthaleneacetic acid and 0.5 mg L^?1 benzylamino purine. An amino acid mixture of glutamine, arginine, glycine, and aspartic acid promoted sustained protoplast division, with an average plating efficiency of 27%. Protoplast-derived colonies formed callus which readily regenerated shoots on fransfer to Murashige and Skoog based agar medium with 2.0 mg L^?1 indoleacetic acid and 1.0 mg L^?1 benzylamino purine. Leaf explants also showed a marked capacity for shoot regeneration in culture.     

Genetic polymorphisms of glutathione S-transferases and cytochrome P450 enzymes as susceptibility factors to systemic lupus erythematosus in southern Brazilian patients

Systemic lupus erythematosus (SLE) is an autoimmune chronic inflammatory disease that presents several clinical manifestations, affecting multiple organs and systems. Immunological, environmental, hormonal and genetic factors may contribute to disease. Genes and proteins involved in metabolism and detoxification of xenobiotics are often used as susceptibility markers to diseases with environmental risk factors. Cytochrome P450 (CYP) enzymes activate the xenobiotic making it more reactive, while the Glutathione S-transferases (GST) enzymes conjugate the reduced glutathione with electrophilic compounds, facilitating the toxic products excretion. CYP and GST polymorphisms can alter the expression and catalytic activity of enzymes. This study aimed to investigate the role of genetic variants of CYP and GST in susceptibility and clinical expression of SLE, through the analysis of GSTM1 null, GSTT1 null, GSTP1*Ile105Val, CYP1A1*2C and CYP2E1*5B polymorphisms. 371 SLE patients from Hospital de Clínicas de Porto Alegre and 522 healthy blood donors from southern Brazil were evaluated. GSTP1 and CYP variants were genotyped using PCR–RFLP and GSTT1 and GSTM1 variants were analyzed by multiplex PCR. Among European-derived individuals, a lower frequency of GSTP1*Val heterozygous genotypes was found in SLE patients when compared to controls (p = 0.005). In African-derived SLE patients, the CYP2E1*5B allelic frequency was higher in relation to controls (p = 0.054). We did not observe any clinical implication of the CYP and GST polymorphisms in patients with SLE. Our data suggest a protective role of the GSTP1*Ile/Val heterozygous genotype against the SLE in European-derived and a possible influence of the CYP2E1*5B allele in SLE susceptibility among African-derived individuals.     

De novo expression of fetal ED-A+ fibronectin and B+ tenascin-C splicing variants in human cardiac allografts: potential impact for targeted therapy of rejection

Management of acute and especially chronic rejection after human cardiac transplantation is still challenging. Chronic rejection, represented by allograft vasculopathy (CAV) and cardiac interstitial fibrosis (CIF) is known to cause severe long-term complications. Rejection associated tissue-remodelling entails the reoccurrence of fetal variants of Fibronectin (Fn) and Tenascin-C (Tn-C), which are virtually absent in adult human organs. In a rat model, an extensive re-expression could be demonstrated for ED-A⁺ Fn with spatial association to CAV and CIF. Thus, it is of great interest to investigate the cardiac tissue expression and distribution in human samples. From 48 heart transplanted patients, 64 tissue specimens derived from right ventricular biopsies were available. Histopathological analysis was performed according to the International Society for Heart and Lung Transplantation (ISHLT) guidelines for the detection of acute rejection. By immunohistochemistry, protein expression of ED-A⁺ Fn, B⁺ Tn-C, alpha-smooth muscle actin, CD31 and CD45 was assessed and analysed semiquantitatively. Co-localisation studies were performed by means of immunofluorescence double labelling. Histopathological analysis of the 64 samples revealed different ISHLT grades (0R in 36 cases, 1R in 20 cases and 2R in 8 cases). There was a distinct and quantitatively relevant re-occurrence of ED-A⁺ Fn and B⁺ Tn-C in most samples. Semi-quantitative evaluation did not show any correlation to the acute rejection grade for all markers. Interestingly, significant correlations to the extent of inflammation could be shown for ED-A⁺ Fn (r = 0.442, p = 0.000) and B⁺ Tn-C (r = 0.408, p = 0.001) as well as between both proteins (r = 0.663, p = 0.000). A spatial association of ED-A⁺ Fn and B⁺ Tn-C to CAV and CIF could be demonstrated. A relevant re-occurrence of ED-A⁺ Fn and B⁺ Tn-C following human heart transplantation could be demonstrated with spatial association to signs of rejection and a significant correlation to tissue inflammation. These data might contribute to the identification of novel biomarkers reflecting the rejection process and to the development of promising strategies to image, prevent or treat cardiac rejection.     

Meta-Analyses of the 5-HTTLPR Polymorphisms and Post-Traumatic Stress Disorder

Objective

To conduct a meta-analysis of all published genetic association studies of 5-HTTLPR polymorphisms performed in PTSD cases

Methods Data Sources

Potential studies were identified through PubMed/MEDLINE, EMBASE, Web of Science databases (Web of Knowledge, WoK), PsychINFO, PsychArticles and HuGeNet (Human Genome Epidemiology Network) up until December 2011. Study Selection: Published observational studies reporting genotype or allele frequencies of this genetic factor in PTSD cases and in non-PTSD controls were all considered eligible for inclusion in this systematic review. Data Extraction: Two reviewers selected studies for possible inclusion and extracted data independently following a standardized protocol. Statistical analysis: A biallelic and a triallelic meta-analysis, including the total S and S'' frequencies, the dominant (S+/LL and S''+/L''L'') and the recessive model (SS/L+ and S''S''/L''+), was performed with a random-effect model to calculate the pooled OR and its corresponding 95% CI. Forest plots and Cochran''s Q-Statistic and I² index were calculated to check for heterogeneity. Subgroup analyses and meta-regression were carried out to analyze potential moderators. Publication bias and quality of reporting were also analyzed.

Results

13 studies met our inclusion criteria, providing a total sample of 1874 patients with PTSD and 7785 controls in the biallelic meta-analyses and 627 and 3524, respectively, in the triallelic. None of the meta-analyses showed evidence of an association between 5-HTTLPR and PTSD but several characteristics (exposure to the same principal stressor for PTSD cases and controls, adjustment for potential confounding variables, blind assessment, study design, type of PTSD, ethnic distribution and Total Quality Score) influenced the results in subgroup analyses and meta-regression. There was no evidence of potential publication bias.

Conclusions

Current evidence does not support a direct effect of 5-HTTLPR polymorphisms on PTSD. Further analyses of gene-environment interactions, epigenetic modulation and new studies with large samples and/or meta-analyses are required.     

Studies of the morphology of chromosomes of some selected species

Karyotypes of twelve species from twenty-four localities in southern Moravia and one locality in Slovakia were investigated. Their counts or karyotypic formulae are as follows:Chenopodium foliosum (Moench) Ascherson: K (2n)=18=16 A^m+2 B^sm;Astragalus austriacus Jacq.: K (2n)=16=8 A^m+8 B^sm;Astragalus exscapus L.: K (2n)=16=10 A^m+4 B^sm+2 C^st;Astragalus cicer L.: K (2n)=64;Astragalus onobrychis L.: K (2n=64 and K (2n)=64+1;Vicia dumetorum L.: K (2n=14=10 A^m+4 B^sm;Vicia sylvatica L.: K (2n)=14=2 A^m+10 B^sm+2 C^st;Vicia pisiformis L.: K (2n)=12=8 A^m+4 B^sm;Vicia cassubica L.: K (2n)=12=4 A^m+6 B^sm+2 C^st;Vicia cracca L. (from five localities in southern Moravia): K (2n)=28=4 A^m+12 B^sm+12 C^st and K (2n)=28+1=5 A^m+12 B^sm+12 C^st;Vicia cracca L. (from one locality in Slovakia): K (2n)=14=2 A^m+6 B^sm+6 C^st;Vicia tenuifolia Roth: K (2n)=24=4 A^m+16 B^sm+4 C^st;Serratula lycopifolia (Vill.) Kern.: K (2n)=60.     

A reliable and efficient protocol for induction of hairy roots in Agastache foeniculum

Hairy root culture system is a valuable tool to study the characteristics of gene expression, gene function, root biology, biochemical properties and biosynthesis pathways of secondary metabolites. In the present study, hairy roots were established in Anise hyssop (Agastache foeniculum) via Agrobacterium rhizogenes. Three strains of Agrobacterium rhizogenes (A4, A7 and 9435), were used for induction of hairy roots in four various explants (hypocotyl, cotyledon, one-month-old leaf and five-month-old leaf) of Anise hyssop. The highest frequency of transformation was achieved using A4 strain in one-month-old leaves (51.1%). The transgenic states of hairy root lines were confirmed by PCR (Polymerase chain reaction) method. High performance liquid chromatography analysis revealed that the production of rosmarinic acid (RA) in transformed roots of A. foeniculum was almost 4-fold higher than that of the non-transformed roots. In a separate experiment, hairy roots obtained from one-month-old leaves inoculated with A4 strain, were grown in liquid medium and the effects of different concentrations of salicylic acid (0.0, 0.01, 0.1 and 1 mM) and chitosan (0, 50, 100 and 150 mg L^?1) (as elicitor) and sucrose (20, 30, 40 and 50 g L^?1) on the growth of hairy roots were evaluated. The results showed that, 30 g L^?1 sucrose and 100 mg L^?1 chitosan increased the biomass of hairy root cultures and application of salicylic acid reduced the growth of hairy roots compared with control roots.     

Location of the genes coding for 18S and 28S ribosomal RNA in the human genome

³H-rRNA obtained from Xenopus laevis tissue cultured cells, or a ³H-cRNA made from Xenopus ribosomal DNA, was used for heterologous in situ hybridisation with human lymphocyte metaphase chromosomes. Prior to hybridisation, chromosome spreads were stained with Quinacrine and selected cells showing good Q-banding photographed; the same cells were then rephotographed after autoradiography and pairs of photographs for each cell were used to make dual karyotypes. The chromosomes within each karyotype were divided into equal sized segments (approx. 0.7 μ), with a fixed number of segments for each chromosome type. The distribution of silver grains between segments showed that the ³H-RNAs hybridised specifically to the nucleolar organising regions of the D and G group chromosomes with no other sites of localised labelling in the complement. Control experiments showed no localisation, with insignificant labelling, when metaphase spreads were incubated in a mixture containing Xenopus ³H-rRNA and competing cold human (HeLa) rRNA. Filter hybridisation experiments on isolated human DNA showed that the Xenopus derived ³H-RNAs hybridised to a fraction of human DNA which was on the heavy side of the main DNA peak and that these RNAs were competed out in the presence of excess cold human rRNA, confirming the specificity of the heterologous hybridisation. In situ hybridisation experiments were also carried out on cells from individuals with one chromosome pair showing heteromorphism for either a very long stalk (nucleolar constriction) subtending a satellite, or a large satellite. It was shown that the chromosome with the large stalk hybridised four times as much ³H-rRNA as its homologue, whereas differences in the sizes of the subtended satellites did not materially affect hybridisation levels indicating that rDNA is located in the stalks and not the satellites. The amount of ³H-rRNA hybridised differs between chromosomes and individuals; these differences are heritable and rDNA can be detected by in situ hybridisation in all three chromosomes number 21 in cells from Down's patients and in translocated chromosomes conta.ining a nucleolar constriction. Different D and G group chromosomes which hybridised equal amounts of ³H-rRNA participated in rosette associations at metaphase in a random fashion in some individuals and in a non-random fashion in others. In all individuals studied chromosomes with large amounts of rDNA were not found to be preferentially involved in association. It was therefore concluded that the probability of a chromosome being involved in the formation of a common nucleolus is not a simple function of its rDNA content and other possible factors are considered.     

Ecological survey of the night monkey,Aotus trivirgatus,in Formosa Province,Argentina

Transect surveys were carried out in northern Argentina during October and November 1977 in order to determine the distribution and abundance ofAotus trivirgatus. The monkeys were seen in pairs with one to two recent young and occurred at a density of approximately six family groups/km².Aotus was only found in relatively moist, riparian, low forests. Some life history traits, such as diurnal activity and the lack of tree-hole use, are distinctive compared to more northern populations.     

Polyhydroxyalkanoate biosynthesis and simultaneous remotion of organic inhibitors from sugarcane bagasse hydrolysate by Burkholderia sp.

Burkholderia sp. F24, originally isolated from soil, was capable of growth on xylose and removed organic inhibitors present in a hemicellulosic hydrolysate and simultaneously produced poly-3-hydroxybutyrate (P3HB). Using non-detoxified hydrolysate, Burkholderia sp. F24 reached a cell dry weight (CDW) of 6.8 g L^?1, containing 48 % of P3HB and exhibited a volumetric productivity (P_P3HB) of 0.10 g L^?1 h^?1. Poly-3-hydroxybutyrate-co-3-hydroxyvalerate copolymers (P3HB-co-3HV) were produced using xylose and levulinic acid (LA) as carbon sources. In shake flask cultures, the 3HV content in the copolymer increased from 9 to 43 mol% by adding LA from 1.0 to 5.0 g L^?1. In high cell density cultivation using concentrated hemicellulosic hydrolysate F24 reached 25.04 g L^?1 of CDW containing 49 % of P3HB and P_P3HB of 0.28 g L^?1 h^?1. Based on these findings, second-generation ethanol and bioplastics from sugarcane bagasse is proposed.     

Hydraulic adjustments in aspen (Populus tremuloides) seedlings following defoliation involve root and leaf aquaporins

Main conclusion

Changes in root and leaf hydraulic properties and stimulation of transpiration rates that were initially triggered by defoliation were accompanied by corresponding changes in leaf and root aquaporin expression. Aspen (Populus tremuloides) seedlings were subjected to defoliation treatments by removing 50, 75 % or all of the leaves. Root hydraulic conductivity (L_pr) was sharply reduced in plants defoliated for 1 day and 1 week. The decrease in L _pr could not be prevented by stem girdling and it was accompanied in one-day-defoliated plants by a large decrease in the root expression of PIP1,2 aquaporin and an over twofold decrease in hydraulic conductivity of root cortical cells (L _pc). Contrary to L _pr and L _pc, 50 and 75 % defoliation treatments profoundly increased leaf lamina conductance (K _lam) after 1 day and this increase was similar in magnitude for both defoliation treatments. Transpiration rates (E) rapidly declined after the removal of 75 % of leaves. However, E increased by over twofold in defoliated plants after 1 day and the increases in E and K _lam were accompanied by five- and tenfold increases in the leaf expression of PIP2;4 in 50 and 75 % defoliation treatments, respectively. Defoliation treatments also stimulated net photosynthesis after 1 day and 3 weeks, although the increase was not as high as E. Leaf water potentials remained relatively stable following defoliation with the exception of a small decrease 1 day after defoliation which suggests that root water transport did not initially keep pace with the increased transpirational water loss. The results demonstrate the importance of root and leaf hydraulic properties in plant responses to defoliation and point to the involvement of PIP aquaporins in the early events following the loss of leaves.     

Bacterial community analysis in chlorpyrifos enrichment cultures via DGGE and use of bacterial consortium for CP biodegradation

The organophosphate pesticide chlorpyrifos (CP) has been used extensively since the 1960s for insect control. However, its toxic effects on mammals and persistence in environment necessitate its removal from contaminated sites, biodegradation studies of CP-degrading microbes are therefore of immense importance. Samples from a Pakistani agricultural soil with an extensive history of CP application were used to prepare enrichment cultures using CP as sole carbon source for bacterial community analysis and isolation of CP metabolizing bacteria. Bacterial community analysis (denaturing gradient gel electrophoresis) revealed that the dominant genera enriched under these conditions were Pseudomonas, Acinetobacter and Stenotrophomonas, along with lower numbers of Sphingomonas, Agrobacterium and Burkholderia. Furthermore, it revealed that members of Bacteroidetes, Firmicutes, α- and γ-Proteobacteria and Actinobacteria were present at initial steps of enrichment whereas β-Proteobacteria appeared in later steps and only Proteobacteria were selected by enrichment culturing. However, when CP-degrading strains were isolated from this enrichment culture, the most active organisms were strains of Acinetobacter calcoaceticus, Pseudomonas mendocina and Pseudomonas aeruginosa. These strains degraded 6–7.4 mg L^?1 day^?1 of CP when cultivated in mineral medium, while the consortium of all four strains degraded 9.2 mg L^?1 day^?1 of CP (100 mg L^?1). Addition of glucose as an additional C source increased the degradation capacity by 8–14 %. After inoculation of contaminated soil with CP (200 mg kg^?1) disappearance rates were 3.83–4.30 mg kg^?1 day^?1 for individual strains and 4.76 mg kg^?1 day^?1 for the consortium. These results indicate that these organisms are involved in the degradation of CP in soil and represent valuable candidates for in situ bioremediation of contaminated soils and waters.     

Effects of metabolic pathway precursors and polydimethylsiloxane (PDMS) on poly-(gamma)-glutamic acid production by Bacillus subtilis BL53

The aims of this study were to evaluate the effects of the addition of metabolic precursors and polydimethylsiloxane (PDMS) as an oxygen carrier to cultures of Bacillus subtilis BL53 during the production of γ-PGA. Kinetics analyses of cultivations of different media showed that B. subtilis BL53 is an exogenous glutamic acid-dependent strain. When the metabolic pathway precursors of γ-PGA synthesis, l-glutamine and a-ketoglutaric acid, were added to the culture medium, production of the biopolymer was increased by 20 % considering the medium without these precursors. The addition of 10 % of the oxygen carrier PDMS to cultures caused a two-fold increase in the volumetric oxygen mass transfer coefficient (k_La), improving γ-PGA production and productivity. Finally, bioreactor cultures of B. subtilis BL53 adopting the combination of optimized medium E, added of glutamine, α-ketoglutaric acid, and PDMS, showed a productivity of 1 g L^?1 h^?1 of g-PGA after only 24 h of cultivation. Results of this study suggest that the use of metabolic pathway precursors glutamine and a-ketolgutaric acid, combined with the addition of PDMS as an oxygen carrier in bioreactors, can improve γ-PGA production and productivity by Bacillus strains .     

Bence jones proteins and light chains of immunoglobulins

The availability of antisera with specificity forλ light chains which have the Mcg- or the non-Mcg-associated amino acid C-region sequence alternations has made possible our immunochemical differentiation of humanλ chains as Mcg⁺ or Mcg^?. One antiserum, prepared against an Mcg⁺ λ chain having the Mcg-associated C-region amino acid residues (asparaginyl, threonyl, and lysyl at positions 116, 118, and 167, respectively), had specificity forλ chains with this C-region sequence. A second antiserum, prepared against an Mcg^? λ chain having the non-Mcg-associated C-region residues (alanyl, seryl, and threonyl at these same three respective positions), had specificity forλ chains with this alternative type of C-region sequence. Immunodiffusion analyses ofλ chains of known amino acid sequence confirmed their chemical classification as Mcg or non-Mcg in type. No association between a particular V-regionλ-chain subgroup and the Mcg factor was evident. Based on sequence and serological analyses, ～ 11 percent ofλ light chains have the Mcg-related C-region sequence alternations. The immunochemical recognition of both Mcg⁺ and Mcg^? light chains isolated from the IgG of normal individuals corroborated the isotypic nature of the Mcg factor. Despite the fact that the Mcg-related substitutions are in the C_λ, the loss of Mcg antigenicity upon cleavage of Mcg⁺ and Mcg^? λ chains into V_L and C_L indicates that the intact light polypeptide chain is essential for expression of the Mcg antigenic factor.