BTEX Sorption by Montmorillonite Organo-Clays: TMPA,Adam, HDTMA

Organo-clay can be utilized for the containment of environmentalpollutants originating from waste sites or accidental spills. Abatch study was conducted using organo-clays produced from aWyoming montmorillonite (SWy) and three organic cations(trimethylphenylammonium (TMPA), trimethylammonium adamantane(Adam), and hexadecyltrimethylammonium (HDTMA)) to characterizeBTEX (benzene, toluene, ethylbenzene, o-, m-, p-xylene) sorption. Sorption data were fitted to two models,with Freundlich resulting in greater correlations of the datathan the Langmuir model (R ² at P ≤0.001-0.05). The Freundlich conditional index (n _f),which describes the experimental sorption characteristics,decreased curvilinearly with organic-cation molecular weights,thus suggesting organo-clays with smaller cations had greaterhydrocarbon retention. Sorption of BTEX followed the order ofTMPA > Adam > HDTMA organo-clays. A similar sequence in themagnitudes of log K _d and log K _omsupportedthis finding. Positive log K _om/K _ow valuesfor TMPA and Adam derivatives indicated there was a greaterretention of BTEX by these organo-clays than octanol. The orderof log K _om for SWy-HDTMA, although concentration-dependent, was analogous to the log K _ow order,indicating partitioning was the dominant sorption mechanism forthe HDTMA-clay. Isotherms for SWy-TMPA and SWy-Adam followed aconvex up pattern. In contract, a concave up curvature, notedfor SWy-HDTMA isotherms, was probably caused by a cosorptiveenhancement process resulting from an effective increase in organic matter content of the organo-clay due to furtherhydrocarbon sorption,in concurrence with a decrease inadsorbate activity coefficients. Values of binding affinityconstant, K _f, for SWy-TMPA were consistently higherthan SWy-Adam. The K _f values determined for totalBTEX sorption by TMPA and Adam derivatives were higher thanthose for the individual hydrocarbons. With SWy-HDTMA, the same order was observed for benzene and toluene; however, ethylbenzene and xylenes had greater K _f values thanthat for the BTEX mixture, possibly due to higher partitioningaffinity of the larger alkylbenzenes. With SWy-HDTM, thesequence of K _f values was: ethylbenzene > m-xylene > p-xylene > o-xylene > toluene >benzene. Trends for SWy-TMPA and SWy-Adam were in contrast tothat of the partitioning order, suggesting that adsorption, ratherthan partitioning, was the primary sorption mechanism for thesetwo organo-clays. With respect to the equilibriumconcentrations, the sorbed amounts for total BTEX mixture weregenerally higher than those for the individual compounds. Ascompared to benzene and toluene, the large-size alkylbenzenesshowed greater partitioning affinity due to their high hydrophobicity.     

Biodiversity of endophytic fungi from seven herbaceous medicinal plants of Malnad region,Western Ghats,southern India

A total of 3611 fungal isolates were recovered from 4200 leaf segments incubated from 7 medicinal herbs during monsoon, winter and summer seasons. These fungal isolates belonged to teleomorphic Asco-mycota （23.5%）, anamorphic Ascomycota producing conidiomata （17.4%）, anamorphic Ascomycota without conidiomata （46.9%）, Zygo-mycota （1.42%） and sterile forms （10.6%）. Chaetomium globosum, As-pergillus niger, Aureobasidium pullulans, Curvularia lunata, Fusarium spp., Penicillium spp., Pestalotiopsis spp., Trichoderma viridae, Cladosporium cladosporioides, were frequently isolated from more than one host plant. The number of endophytic isolates was higher in winter than in monsoon and summer seasons.     

Coastal ecosystem-based management with nonlinear ecological functions and values

A common assumption is that ecosystem services respond linearly to changes in habitat size. This assumption leads frequently to an "all or none" choice of either preserving coastal habitats or converting them to human use. However, our survey of wave attenuation data from field studies of mangroves, salt marshes, seagrass beds, nearshore coral reefs, and sand dunes reveals that these relationships are rarely linear. By incorporating nonlinear wave attenuation in estimating coastal protection values of mangroves in Thailand, we show that the optimal land use option may instead be the integration of development and conservation consistent with ecosystem-based management goals. This result suggests that reconciling competing demands on coastal habitats should not always result in stark preservation-versus-conversion choices.     

Ochratoxin A: Carryover from animal feed into livestock and the mitigation strategies

This review aims to highlight the effects of ochratoxin A (OTA) in the feed of meat-producing animals. The accumulation of OTA in feed and its distribution in various farm animals were compared and evaluated. Primarily, the oral administration of OTA-contaminated feed and the predisposition in an animal''s vital organ were critically examined in this work. The collated reports show that OTA directly associated with endemic nephropathy and its high concentration leads to degeneration of liver cells, and necrosis of intestinal and lymphoid tissues. At present, limited reports are available in the recent literature on the problems and consequences of OTA in feed. Therefore, this review focused on the OTA carryover from feed to farm animals and the interaction of its secondary metabolites on their biochemical parameters. Hence, this report provides greater insights into animal health related to OTA residues in meat and meat products. This article also explores mitigation strategies that can be used to prevent the carryover effects of OTA in livestock feeds and the effects in the food chain.     

Ecology of soil microflora and mycorrhizal symbionts in degraded forests at two altitudes

Summary Microbial populations were estimated in four different forest stands at different regenerational stages, two each at higher and lower altitudes. The fungal and bacterial populations showed marked seasonal variations at both altitudes. Quantitatively, the bacterial population was higher than the fungal population. Although 25 fungal species were isolated at the lower altitude, only 15 were obtained at the higher altitude. Penicillium chrysogenum and Trichoderma viride were dominant at the lower and higher altitudes, respectively. In the more degraded forest stand at the lower altitude both the fungal and the bacterial population showed a significant positive correlation with organic C (r=0.658 and 0.735, respectively), whereas in the less degraded forest stand there was a significant correlation only between the fungal population and organic C (r=0.835). At the higher altitude, however, a highly significant correlation (P<0.05) was observed between the fungal population, soil moisture and organic C in both the forest stands. Disturbance to the soil and vegetation adversely affected the microbial population, and also affected endogonaceous spores. At the lower altitude, plants in the more degraded forest stand were more mycotrophic compared to those in the less degraded stand. The level of mycorrhizal infection showed a highly positive correlation with soil moisture, organic C, total N, and available P. The spore population, however, was correlated negatively with these parameters. Three different endogonaceous genera, Glomus, Gigaspora, and Acaulospora, were identified during the course of investigation. Glomus, however, was dominant.     

Acidification of Surface Water in Central India

The results of the seasonal analysis of the chemistry of rain, fog and surface water of central India for the two years: June 1996 to May 1998 are presented. A total of 636 rain water samples, 146 fog water samples and 226 surface water samples of 8 locations: namely, Ambikapur, Baikunthpur, Korba, Bilaspur, Raipur, Bhilai, Dallirajhara and Kanker, from different sites were collected for the present study. This paper documents the occurrence of acidic rain and fog events and their effect on surface water pH and aquatic life in central India. Most of the rain and fog water samples collected from Baikunthpur and Korba sites were found to be acidic in nature (i.e. pH < 5). The volume weighted mean pH of rain and fog water samples of these sites was 4.8 and 4.4 with lowest pH 4.4 and 4.0, respectively. However, samples from Ambikapur, Bilaspur, Raipur and Bhilai were slightly acidic and their pH values were always around 5.8. One reservoir (mean pH 5.8) and two stop dams (mean pH 4.4 and 4.2) in Baikunthpur area were found to be acidic. The effect of acidification of water on metal-accumulation in muscles of fishes was studied. Concentrations of Al, Hg, Mn, Cd and Pb were higher in fish from acid, than from less acid waters. Causes of acidification of the atmospheric water and surface water are critically discussed.     

Identification of alleles at two loci controlling resistance to Phomopsis stem blight in narrow-leafed lupin (Lupinus angustifolius L.)

The genetics of resistance to Phomopsis stem blight caused by Diaporthe toxica Will., Highet, Gams & Sivasith. in narrow-leafed lupin (Lupinus angustifolius L.) was studied in crosses between resistant cv. Merrit, very resistant breeding line 75A:258 and susceptible cv. Unicrop. A non-destructive glasshouse infection test was developed to assess resistance in the F₁, F₂, selected F₂-derived F₃ (F_2:3) families, and in selfed parent plants. The F₁ of Unicrop × 75A:258 (and reciprocal cross) was very resistant, and the F₂ segregated in a ratio of 3:1 (resistant: susceptible), which suggested the presence of a single dominant allele for resistance in 75A:258. In Merrit × Unicrop (and reciprocal), the F₁ was moderately resistant, and the F₂ segregated in a ratio of 3:1 (resistant: susceptible). Thus Merrit appeared to carry an incompletely dominant resistance allele for resistance. The F₁ of Merrit × 75A:258 (and reciprocal) was very resistant and the F₂ segregated in a ratio of 15:1 (resistant: susceptible), which supported the existence of independently segregating resistance alleles for resistance in 75A:258 and Merrit. Alleles at loci for early flowering (Ku) and speckled seeds (for which we propose the symbol Spk) segregated normally and independently of the resistance alleles. Resistant F₂ plants gave rise to uniformly resistant or segregating F_2:3 families, whereas susceptible F₂ plants gave rise only to susceptible F_2:3 families. However, the variation in resistance in the F₂ and some F_2:3 families of crosses involving 75A:258, from moderately to extremely resistant, was greater than that expected by chance or environmental variation. We propose the symbols Phr1 to describe the dominant resistance allele in 75A:258, and Phr2 for the incompletely dominant resistance allele in Merrit. Phr1 appears to be epistatic to Phr2, and expression of Phr1 may be altered by independently segregating modifier allele(s). This revised version was published online in July 2006 with corrections to the Cover Date.     

A comparison of growth, survival rate and number of marketable koi carp produced under different management regimes in earthen ponds and concrete tanks

To compare the growth performance of koi carp, Cyprinus carpio var. koi, produced in concrete tanks (2.13 × 0.91 × 1.22 m; capacity: 2,000 l each) and earthen ponds (9.1 × 6.10 × 1.07 m; capacity: 59650 l each), fish larvae (stocking size: 0.12 ± 0.008 g) were cultured for 11 weeks and individual weight gain, survival rate and number of marketable fish produced were compared among four management regimes for each culture system: (1) live zooplankton fed to fish larvae in ponds (PLF) and tanks (TLF); (2) application of poultry manure in ponds (PPM) and tanks (TPM); (3) application of cow manure in ponds (PCD) and tanks (TCD); and (4) a control treatment for ponds (PC) and tanks (TC), where a commercial feed was applied. There were three replicates for each treatment. Weight gain of koi carp was highest in the PLF treatment, followed in decreasing order by TLF, PPM, PCD, TPM, TCD, PC and TC treatments (P < 0.05). There was a significant difference in the survival of koi carp among the treatments, ranging from 67.83% in TC to 95.50% in PLF. The number of marketable fish produced was highest in the PLF treatment, followed in decreasing order by TLF, PPM and PCD treatments. However, none of the fish produced in the TPM, TCD, PC and TC treatments attained marketable size. Significantly higher (P < 0.05) values of pH and dissolved oxygen (for water samples collected weekly at 9 A.M.) were obtained in the live food and control treatments (for both tanks and ponds), compared to the manured treatments. The concentration of total alkalinity, BOD, PO₄-P, NO₃-N and specific conductivity were significantly higher (P < 0.05) in PPM and PCD, compared to other treatments. NO₂-N and NH₄-N values were significantly higher (P < 0.05) in TPM and TCD, than other treatments. The results suggest that introduction of live zooplankton into culture units result in higher growth of koi carp larvae compared to manure based systems. Earthen ponds appeared to be better alternative to concrete tanks for manure application through maintenance of better water quality due to their higher assimilatory capacity and greater abundance of plankton which resulted in better growth of cultured fish.     

The role of the reticuloendothelial system in the immunopathology of Marek's disease

The role of macrophages in immunity against Marek's disease (MD) was studied. Chickens of one group were subjected to depletion of macrophages using repeated doses of Francil amorphous silica and those of another group were subjected to activation of macrophages using repeated doses of brewer's thioglycollate broth. Chickens of a third group were vaccinated with herpesvirus of turkeys FC 126 vaccine followed by depletion of macrophages. Chickens of these three groups, as well as groups of healthy unvaccinated and healthy vaccinated chickens, were challenged with virulent MD virus. A sixth group of healthy uninfected chickens was kept as a control. The results, based on clinical signs, gross and histopathological studies and agar gel precipitation test (AGPT) for antibodies, indicated that activation of macrophages enhanced immunity against MD and depletion of macrophages had the opposite effect. The protective effect of vaccination against MD was also lowered by depletion of macrophages. The results of AGPT indicated retardation of MD virus replication by macrophage activation and the reverse on depletion.     

Assessment of Genetic Variability in the Coding Sequence of Melatonin Receptor Gene (MTNR1A) in Tropical Arid Sheep Breeds of India

Seasonal behaviour in sheep, which varies in tropical and temperate environmental conditions, is a matter of study, because it can provide a clue to address the problem of seasonality in sheep. Melatonin receptor is the membrane‐bound G‐coupled receptor, sensing the message of photoperiodic cues thorough melatonin. Restriction fragment length polymorphism (RFLP) studies were carried out to assess the variability of gene at G612A and C606T SNPs in MTNR1A gene, which have been studied to be markers for out‐of‐season breeding. Allelic frequency distribution corresponded to higher frequency of GG and CC genotype, in tropical arid sheep breed in comparison with temperate region sheep breed. PCR amplification of MTNR1A gene of 30 animals was performed and single nucleotide polymorphisms (SNPs) identification was carried out using Lasergene software. Seven SNPs/mutations were identified, but most of them were synonymous, except the one G706A, leading to substitution of valine by isoleucine. Polyphen‐2 analysis of G706A mutation revealed that it is a benign mutation. Two important SNPs C426T and G555A, which were identified in temperate sheep breeds, could not be traced in Magra and Marwari breeds of sheep. Thus, the Magra and Marwari breeds of tropical, arid region demonstrated the presence of both polymorphic SNPs markers G612A and C606T, associated with out‐of‐season breeding. GG and CC genotypes were having a higher prevalence in the studied population.