Molecular Pathway Reconstruction and Analysis of Disturbed Gene Expression in Depressed Individuals Who Died by Suicide

Molecular mechanisms behind the etiology and pathophysiology of major depressive disorder and suicide remain largely unknown. Recent molecular studies of expression of serotonin, GABA and CRH receptors in various brain regions have demonstrated that molecular factors may contribute to the development of depressive disorder and suicide behaviour. Here, we used microarray analysis to examine the expression of genes in brain tissue (frontopolar cortex) of individuals who had been diagnosed with major depressive disorder and died by suicide, and those who had died suddenly without a history of depression. We analyzed the list of differentially expressed genes using pathway analysis, which is an assumption-free approach to analyze microarray data. Our analysis revealed that the differentially expressed genes formed functional networks that were implicated in cell to cell signaling related to synapse maturation, neuronal growth and neuronal complexity. We further validated these data by randomly choosing (100 times) similarly sized gene lists and subjecting these lists to the same analyses. Random gene lists did not provide highly connected gene networks like those generated by the differentially expressed list derived from our samples. We also found through correlational analysis that the gene expression of control participants was more highly coordinated than in the MDD/suicide group. These data suggest that among depressed individuals who died by suicide, wide ranging perturbations of gene expression exist that are critical for normal synaptic connectively, morphology and cell to cell communication.     

Variation among strains of Xanthomonas campestris pv. vasculorum from Mauritius and other countries based on fatty acid analysis

Fatty acid profiling was used to study variation amongst strains of Xanthomonas campestris pv. vasculorum (Xcv). They could be divided into five groups using cellular fatty acid profiles. Group A strains represent a new and little known taxon and all came from plants of broom bamboo (Thysanolaena maxima) from Mauritius. Group B strains included the Xcv pathotype reference strain and were from palms, broom bamboo and sugarcane from Mauritius, Reunion and Australia. Group C contained southern African and Malagasy strains from sugarcane and maize, together with X. campestris pv. holcicola strain. No Mascarene strains fell into this group. Group D strains isolated from sugarcane, maize and royal palm (Roystonea regia) were from Mauritius and Reunion, the earliest known strains coming from Réunion. These groups represented in the Mascarene Islands possibly belong to three different Xanthomonas species. A further Group E comprised one Xcv strain (NCPPB 182) from Puerto Rico, one X. vasicola pv. holcicola strain plus 6 other unclassified Xanthomonas strains causing red stripe disease symptoms in sugarcane. Three of these groups occur on Mauritius and two occur on Réunion. Group B strains originally caused serious problems in noble canes. As resistant interspecific hybrids were introduced, group D strains appeared in Mauritius possibly being introduced from Reunion but having similar host ranges within the Gramineae and Palmae. The findings that 3 of these groups (A, B, D) can cause gumming disease in a grass species (T. maxima) and that 2 of them (B, D) also cause gumming disease in sugar cane (Gramineae) and palms (Palmae) is unusual.     

The role of mast cell degranulation products in mast cell hyperplasia. I. Mechanism of action of nerve growth factor

A variety of mast cell degranulating agents have previously been shown to induce mast cell hyperplasia in adult rats. In neonates 2.5 S nerve growth factor (NGF) induces a hyperplasia of both mucosal and connective tissue mast cells (MMC and CTMC). We have examined the role of the potent mast cell degranulating properties of NGF on its ability to induce mast cell hyperplasia. Administration of NGF in combination with the mast cell stabilizing agent disodium cromoglycate was found to abrogate the CTMC hyperplasia induced by NGF alone. Treatment of neonatal rats with the alternate degranulating agent compound 48/80 was found to induce a limited CTMC but not a MMC hyperplasia. A supernatant obtained by degranulating purified adult rat peritoneal mast cells with anti-IgE was found to induce hyperplasia of the CTMC population similar to that observed with NGF administration. However, this degranulation product supernatant only induced a limited MMC hyperplasia as judged by RMCP II content of the tissues. These results suggest that NGF has dual action inducing mast cell hyperplasia; CTMC hyperplasia being dependent on the ability of NGF to degranulate mast cells. MMC hyperplasia induced by NGF is independent of CTMC degranulation. Degranulation products from peritoneal mast cells act to increase both MMC and CTMC populations in the neonate. These data suggest that the CTMC population may be regulated by an autocrine positive feedback mechanism in vivo.     

Analysis of B-genome chromosome introgression in interspecific hybrids of Brassica napus × B. carinata

Brassica carinata, an allotetraploid with B and C genomes, has a number of traits that would be valuable to introgress into B. napus. Interspecific hybrids were created between B. carinata (BBCC) and B. napus (AACC), using an advanced backcross approach to identify and introgress traits of agronomic interest from the B. carinata genome and to study the genetic changes that occur during the introgression process. We mapped the B and C genomes of B. carinata with SSR markers and observed their introgression into B. napus through a number of backcross generations, focusing on a BC(3) and BC(3)S(1) sibling family. There was close colinearity between the C genomes of B. carinata and B. napus and we provide evidence that B. carinata C chromosomes pair and recombine normally with those of B. napus, suggesting that similar to other Brassica allotetraploids no major chromosomal rearrangements have taken place since the formation of B. carinata. There was no evidence of introgression of the B chromosomes into the A or C chromosomes of B. napus; instead they were inherited as whole linkage groups with the occasional loss of terminal segments and several of the B-genome chromosomes were retained across generations. Several BC(3)S(1) families were analyzed using SSR markers, genomic in situ hybridization (GISH) assays, and chromosome counts to study the inheritance of the B-genome chromosome(s) and their association with morphological traits. Our work provides an analysis of the behavior of chromosomes in an interspecific cross and reinforces the challenges of introgressing novel traits into crop plants.     

Nifedipine induces apoptosis in cultured vascular smooth muscle cells from spontaneously hypertensive rats

Apoptosis (programmed cell death) of smooth muscle cells (SMC) in blood vessels is an essential process involved in the control of vessel wall structure. Several antihypertensive drugs currently used in therapy may exert their pharmacological effects by promoting SMC apoptosis. The biochemical events which regulate SMC apoptosis in the vessel wall are complex, and not well understood. We therefore investigated whether treatment of cultured SMC from normotensive Wistar-Kyoto rats (WKY) and from spontaneously hypertensive rats (SHR) with selected antihypertensive drugs would induce SMC apoptosis. We treated aortic SMC from WKY and SHR in vitro with the L-type Ca2+ channel antagonist, nifedipine; with the nitric oxide donor, sodium nitroprusside (SNAP); with forskolin (an activator of adenylyl cyclase); or with thapsigargin (a selective inhibitor of the sarcoplasmic reticulum (SR), Ca2+-ATPase); and compared their apoptosis-promoting effects in SMC derived from the two strains of rats. SMC were derived from the thoracic aorta of 3-4-week-old WKY and SHR, and were used in passages 7-10. Apoptotic cells were detected by in-situ end labeling using the terminal deoxynucleotide transferase-mediated dUTP-nick end-labeling (TUNEL) method, and by morphological examination. We found that: 1) Treatment of cultured aortic SMC with the L-type Ca2+ channel antagonist, nifedipine (5 X 10(-5) M) for 24 hours induced a significantly higher level of apoptosis in SHR cells than in SMC from WKY. Cells from WKY, following exposure to nifedipine for 72 hours, exhibited a similar response to the cells from SHR treated for 24 hours. This was detectable by both morphological criteria as well as DNA labeling by the TUNEL technique. 2) Similar treatment of these cells with thapsigargin (1 x 10(-7) M) led to morphological alterations characteristic of apoptotic cells in SMC from both WKY and SHR, and cells from SHR but not WKY were labeled by the TUNEL technique at 24 hours. The TUNEL method did however identify cells from both WKY and SHR as apoptotic after 48 and 72 hours of treatment. 3) The addition of SNAP, or forskolin to the cultured SMC induced significant, but low levels of apoptosis in WKY SMC only. This selective apoptosis-promoting effect of nifedipine in SHR SMC may result from differences in the control of intracellular Ca2+ between the two strains of cells, or it may indicate that the signaling pathways which regulate apoptosis are different in SMC from the normotensive and the hypertensive rats. Our findings imply that SMC apoptosis may be a selective target for pharmacological intervention in hypertension.     

Determination of peroxidative halogenation in mixtures of chloride and bromide

A method for the differentiation of chlorinated and brominated products from peroxidative oxidation of mixtures of the halides is presented. Chlorination or bromination of monochlorodimedone (MCD) by fungal chloroperoxidase (CPO) was measured by loss of MCD absorbance. Although the Vmax was similar for both halides [approximately 0.08 mM (2 min)-1], the apparent Km for chlorination was 10 times greater than that for bromination (5.88 vs 0.67 mM). Chlorination was also quantitated as I3- produced from N-chlorotaurine and I-. The Vmax [0.076 mM (2 min)-1] and apparent Km (6.31 mM) determined by this method agreed with those determined with MCD. Selective reduction by H2O2 of the I-oxidizing potential of N-bromotaurine allowed determination of the brominated product from the difference between the amounts of halogenated MCD and N-chlorotaurine. The brominated product predominated at saturating and at physiologic halide levels. Hence, it is suggested that Br- plays a significant role in halogenation even though in vivo levels of Cl- are equal to or greater than 1000 times those Br-.     

Which provenance and where? Seed sourcing strategies for revegetation in a changing environment

Revegetation is one practical application of science that should ideally aim to combine ecology with evolution to maximise biodiversity and ecosystem outcomes. The strict use of locally sourced seed in revegetation programs is widespread and is based on the expectation that populations are locally adapted. This practice does not fully integrate two global drivers of ecosystem change and biodiversity loss: habitat fragmentation and climate change. Here, we suggest amendments to existing strategies combined with a review of alternative seed-sourcing strategies that propose to mitigate against these drivers. We present a provenancing selection guide based on confidence surrounding climate change distribution modelling and data on population genetic and/or environmental differences between populations. Revegetation practices will benefit from greater integration of current scientific developments and establishment of more long-term experiments is key to improving the long-term success. The rapid growth in carbon and biodiversity markets creates a favourable economic climate to achieve these outcomes.     

Proximity and grooming patterns reveal opposite-sex bonding in Rwenzori Angolan colobus monkeys (<Emphasis Type="Italic">Colobus angolensis ruwenzorii</Emphasis>)

Close proximity and social grooming are important bonding mechanisms in primates. These behaviors show the social structure of a species and many studies have found positive correlations between the degree of kinship and grooming and proximity. We used 1 year of data collected via instantaneous scan sampling on a large “supertroop” of Colobus angolensis ruwenzorii at Lake Nabugabo, Uganda, to examine partner preferences for grooming and nearest neighbors in each age-sex class. Little is known about this species, so we based our hypotheses on congeners. Of the five species of black-and-white colobus, data on sex-biased dispersal patterns are available for three (C. guereza, C. vellerosus, and C. polykomos), all of which show male-biased dispersal with occasional female dispersal. We thus predicted that female C. a. ruwenzorii would be more strongly bonded than males, showing greater proximity and grooming. We did not expect bonding between the sexes since congeners do not show this pattern. We found that among adult dyads, males and females were more likely to be found in loose proximity, and to groom, than would be expected given group composition. Conversely, both males and females had relatively weak same-sex relationships. Between the sexes, adult males had higher proximity and grooming indices with adult females without infants than with females with infants. These observations indicate that this subspecies is cross-bonded and that both sexes may disperse. Furthermore, our findings suggest that the social organization and social structure of C. a. ruwenzorii differ greatly from other black-and-white colobus species.