Impact of the changing ecology on intertidal polychaetes in an anthropogenically stressed tropical creek,India

Polychaete assemblages and associated environment of 12 strategically selected intertidal stations along the extremely polluted Thane creek on the west coast of India were studied monthly for a year and compared with past available data to investigate changes in the creek ecology due to various anthropogenic activities like industrial, domestic, and solid waste disposal along with land reclamation. Shannon’s index (H′) varied spatially from 0.4 to 1.5, Margalef richness index (d) from 0.4 to 1.1, and evenness index (J) from 0.3 to 0.7 indicating poor polychaete diversity. Ceratonereis burmensis and Lycastis indica were the most abundant and omnipresent polychaetes in the creek indicating their tolerance and adaptability to various degrees of pollution. Hydro-sedimentological investigations revealed enhancement of total nitrogen (TN) and organic carbon (C_org) load and hypoxic levels of dissolved oxygen (DO) over the years. Silt component of sediment was increasing, with proportionate decrease in clay due to various anthropogenic disturbances. Species richness was correlated positively with clay and negatively with silt. The BIO-ENV analyses indicated the strong influence of NO₃ ⁻-N, clay and TN on the distribution patterns of polychaetes. Pollution-tolerant polychaetes like Lycastis ounaryensis and Polydora tentaculata were getting replaced by more pollution-resistant species like C. burmensis in the creek due to changing sediment texture, reduced oxygen levels, and increased C_org and TN.     

Distinctively variable sequence-based nuclear DNA markers for multilocus phylogeography of the soybean- and rice-infecting fungal pathogen Rhizoctonia solani AG-1 IA

A series of multilocus sequence-based nuclear DNA markers was developed to infer the phylogeographical history of the Basidiomycetous fungal pathogen Rhizoctonia solani AG-1 IA infecting rice and soybean worldwide. The strategy was based on sequencing of cloned genomic DNA fragments (previously used as RFLP probes) and subsequent screening of fungal isolates to detect single nucleotide polymorphisms (SNPs). Ten primer pairs were designed based on these sequences, which resulted in PCR amplification of 200-320 bp size products and polymorphic sequences in all markers analyzed. By direct sequencing we identified both homokaryon and heterokaryon (i.e. dikaryon) isolates at each marker. Cloning the PCR products effectively estimated the allelic phase from heterokaryotic isolates. Information content varied among markers from 0.5 to 5.9 mutations per 100 bp. Thus, the former RFLP codominant probes were successfully converted into six distinctively variable sequence-based nuclear DNA markers. Rather than discarding low polymorphism loci, the combination of these distinctively variable anonymous nuclear markers would constitute an asset for the unbiased estimate of the phylogeographical parameters such as population sizes and divergent times, providing a more reliable species history that shaped the current population structure of R. solani AG-1 IA.     

Expression profile of genes associated with mastitis in dairy cattle

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF- α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with and three without mastitis per breed. Gene expression was analyzed by real-time PCR. IL-10 gene expression was higher in the group of BW and Gyr cows with mastitis compared to animals free of infection from both breeds (p < 0.05). It was also higher in BW Holstein animals with clinical mastitis (p < 0.001), but it was not significant when Gyr cows with and without mastitis were compared (0.05 < p < 0.10). Among healthy cows, BW Holstein animals tended to present a higher expression of all genes studied, with a significant difference for the IL-2 and IFN- γ genes (p < 0.001). For animals with mastitis no significant difference in gene expression was observed between the two breeds. These findings suggest that animals with mastitis develop a preferentially cell-mediated immune response. Further studies including larger samples are necessary to better characterize the gene expression profile in cows with mastitis.     

Characterization of polymorphic microsatellites for the rough periwinkle gastropod, Littorina saxatilis (Olivi, 1792) and their cross-amplification in four congeners

Eight new microsatellite loci were characterized for Littorina saxatilis (Olivi, 1792) and tested for their cross-hybridization in congeners. All loci were polymorphic in Irish and Celtic Sea samples, with an average number of alleles per locus of 15 (range, 6–31). Observed and expected locus heterozygosities ranged from 26 to 85% and from 53 to 92%, respectively. Three loci showed excess homozygosity and significant departures from Hardy–Weinberg expectations in one sample, possibly due to null alleles, population structuring or inbreeding. No linkage disequilibrium was detected among loci within samples. A high degree of cross-hybridization was observed in closely related congeners and most loci were polymorphic. These markers will be useful for investigating population genetic diversity and connectivity in coastal populations, especially for marine reserve design.     

Effects of exercise training on papain-induced pulmonary emphysema in Wistar rats.

The purpose of the present study was to evaluate the role of exercise training on the development of papain-induced emphysema in rats. Our hypothesis was that the increase in pulmonary tissue stretching associated with exercise could increase the severity of a protease-induced emphysema. Wistar rats were randomly assigned to four groups (n = 10 for each group) that received, respectively, intratracheal infusion of papain (6 mg in 1 ml of 0.9% NaCl) or vehicle and were submitted or not to a protocol of exercise on a treadmill. Rats exercised at 13.3 m/min, 6 days/wk, for 9 wk (increasing exercise time, from 10 to 35 min). We measured respiratory system elastance and resistance, the size and weight of the heart, and pulmonary mean linear intercept (Lm). After 9 wk of exercise training, there were no differences in respiratory system resistance and elastance values among the four experimental groups. Volume of the heart was significantly greater in rats submitted to exercise training (P = 0.007) compared with sedentary rats due to increases in volumes of both right and left cardiac chambers. Lm was significantly greater in rats that received papain compared with saline-infused rats (P = 0.025). Surprisingly, this was true, even though there was no significant decrease in elastance, possibly due to connective tissue remodeling. However, Lm was significantly greater in papain + exercise rats compared with rats that received papain and were not submitted to exercise. We conclude that exercise training can increase alveolar damage induced by papain infusion.     

Structure-activity relationship of wedelolactone analogues: structural requirements for inhibition of Na+, K+ -ATPase and binding to the central benzodiazepine receptor

Coumestans 2a-i, bearing different patterns of substitution in A- and D-rings, were synthesized and evaluated as inhibitors of kidney Na+, K+ -ATPase and ligands for the central benzodiazepine (BZP) receptor. The presence of a hydroxyl group in position 2 favours the effect on Na+, K+ -ATPase but decreases the affinity for the BZP receptor, allowing the design of more selective molecules than the natural wedelolactone. On the other hand, the presence of a catechol in ring D is important for the effect on both molecular targets.     

Aquatic macrophytes in the large, sub-tropical Itaipu Reservoir, Brazil

In the last three decades, rapid assessment surveys have become an important approach for measuring aquatic ecosystem biodiversity. These methods can be used to detect anthropogenic impacts and recognize local or global species extinctions. We present a floristic survey of the aquatic macrophytes along the Brazilian margin of the Itaipu Reservoir conducted in 2008 and compare this with a floristic survey conducted ten years earlier. We used ordination analysis to determine whether assemblage composition differed among reservoir arms. Macrophyte species were sampled in each of the 235 sampling stations using a boat, which was positioned inside three places of each macrophyte stand to record species and search for small plants. We also collected submerged plants using a rake with the boat moving at constant velocity for ten minutes. We assigned individual macrophyte species to life form and identified representative species for each life form. A total of 87 macrophyte taxa were identified. The "emergent" life forms contained the highest number of species, followed by "rooted submerged" life forms. The extensive survey of macrophytes undertaken in September 2008 recorded more species than a survey conducted between 1995 and 1998. This could be due to changes in water physico-chemistry, disturbances due to water drawdown and the long period between surveys, which may have allowed natural colonization by other species. Additionally, differences in the classification systems and taxonomic resolution used in the surveys may account for differences in the number of species recorded. Assemblage composition varied among the arms and was affected by underwater radiation (as measured using a Secchi disk) and fetch. Five non-native species were found. Two of these non-native species (Urochloa subquadripara and Hydrilla verticillata) are of special concern because they have a high frequency of occurrence and occupy large marginal areas of the reservoir. Future surveys should be conducted to determine the habitat most frequently colonized by these species. This would allow management strategies to be developed to protect native aquatic biota and prevent interference with the recreational and commercial uses of the Itaipu Reservoir.     

Population structure and linkage disequilibrium unravelled in tetraploid potato

Association mapping is considered to be an important alternative strategy for the identification of quantitative trait loci (QTL) as compared to traditional QTL mapping. A necessary prerequisite for association analysis to succeed is detailed information regarding hidden population structure and the extent of linkage disequilibrium. A collection of 430 tetraploid potato cultivars, comprising two association panels, has been analysed with 41 AFLP^® and 53 SSR primer combinations yielding 3364 AFLP fragments and 653 microsatellite alleles, respectively. Polymorphism information content values and detected number of alleles for the SSRs studied illustrate that commercial potato germplasm seems to be equally diverse as Latin American landrace material. Genome-wide linkage disequilibrium (LD)—reported for the first time for tetraploid potato—was observed up to approximately 5 cM using r ² higher than 0.1 as a criterion for significant LD. Within-group LD, however, stretched on average twice as far when compared to overall LD. A Bayesian approach, a distance-based hierarchical clustering approach as well as principal coordinate analysis were adopted to enquire into population structure. Groups differing in year of market release and market segment (starch, processing industry and fresh consumption) were repeatedly detected. The observation of LD up to 5 cM is promising because the required marker density is not likely to disable the possibilities for association mapping research in tetraploid potato. Population structure appeared to be weak, but strong enough to demand careful modelling of genetic relationships in subsequent marker-trait association analyses. There seems to be a good chance that linkage-based marker-trait associations can be identified at moderate marker densities.     

Colonisation of soft lining materials by micro‐organisms

doi:10.1111/j.1741‐2358.2009.00300.x
Colonisation of soft lining materials by micro‐organisms Objective: This study evaluated the in vitro adherence of pathogenic micro‐organisms, Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa, to soft lining materials and their inhibitory effect on these micro‐organisms. Materials and Methods: To measure adherence, specimens of Molloplast B and Ufi Gel P were inoculated [10⁷ colony‐forming units per millimetre (cfu/ml)] with TSB media containing the micro‐organisms. To determine the number of micro‐organisms in the 10^?2–10^?5 dilutions, 25 μl of the suspension were transferred to plates of selective media. Colony counts of each specimen were quantified (cfu/ml). The surface roughness was measured with a perfilometer to assess the relationship between the adherence of micro‐organisms and surface roughness of each material. For the inhibition test, specimens of materials were placed in agar plates inoculated individually with the micro‐organisms. After 48 h, the inhibition zones around the specimens were measured. Results: None of the materials exhibited inhibition zones. The number of cfu/ml of S. aureus and P. aeruginosa were significantly greater than C. albicans for both materials. The Ufi Gel P exhibited greater adherence of C. albicans than Molloplast B. No correlation was observed between the adherence of micro‐organisms and surface roughness. Conclusion: The surface roughness of the materials is not the only factor governing micro‐organism adherence.