Tracking and identifying wastewater toxicants and assessing their biodegradation products

Screening of wastewater effluents from municipal and industrial wastewater treatment plants with biotests showed that the treated wastewater effluents possess only minor acute toxic properties towards whole organisms (e.g. bacteria, algae, daphnia), if any. In vitro tests (sub-mitochondrial membranes and fish hepatocytes) were generally more susceptible to the effluents. Most of the effluents indicated the presence of hormonally active compounds, as the production of vitellogenin, an egg yolk precursor protein, was induced in fish hepatocytes exposed to wastewater. In addition, indications of slight genotoxic potential was found in one effluent concentrate with a recombinant bacteria test. Reverse electron transport (RET) of mitochondrial membranes was used as a model test to conduct effluent assessment followed by toxicant characterisations and identifications. Using a modified U.S. EPA Toxicity Identification Evaluation Phase I scheme and additional case-specific methods, the main compound in a pulp and paper mill effluent causing RET inhibition was characterised to be an organic, relatively hydrophilic high molecular weight (HMW) compound. The toxicant could be verified as HMW lignin by structural analyses using nuclear magnetic resonance. In the confirmation step commercial and in-house extracted lignin products were used. The possible toxicity related structures were characterised by statistical analysis of the chemical breakdown structures of laboratory-scale pulping and bleaching effluents and the toxicities of these effluents. Finally, the biological degradation of the identified toxicant and other wastewater constituents was evaluated using bioassays in combination with chemical analyses. Biological methods have not been used routinely in establishing effluent discharge limits in Finland. However, the biological effects observed in this study could not have been predicted using only routine physical and chemical effluent monitoring parameters. Therefore chemical parameters cannot be considered to be sufficient in controlling effluent discharges especially in case of unknown, possibly bioaccumulative, compounds that may be present in small concentrations and may cause chronic effects.

Investigation of potential antibacterial action for postharvest copper treatments of cut Acacia holosericea

The mechanisms of action of Cu 2+ in improving the longevity of cut flowers and foliage have not been elucidated. Possible antimicrobial action of Cu 2+ against stem end and vase solution colonising bacteria was investigated using Cu 2+ treatments optimised for cut Acacia holosericea A. Cunn. ex G. Don foliage stems. These treatments were a 5h pulse with 2.2mM Cu 2+ or a 0.5mM Cu 2+ vase solution versus a deionised water (no Cu 2+) control. Bacterial growth over time was assessed by a standard plate count agar technique and with scanning electron microscopy. Cu 2+ treatments significantly extended the cut foliage vase life. However, they did not have sustained antibacterial activity against stem end or vase solution colonising bacteria. Also, regular recutting of 1-2cm from the stem ends did not substantially improve either cut stem water relations or longevity. The positive effects of Cu 2+ treatments were unaffected by the repeated stem end recutting. It was concluded that the primary mechanism of Cu 2+ was not antibacterial. Moreover, naturally growing vase solution and stem end microbial populations had relatively insignificant effects on cut A. holosericea vase life. Research into alternative mechanisms of Cu 2+ is required. © 2012 Elsevier B.V.

Effect of temperature on the survival of Aconophora compressa Walker (Hemiptera: Membracidae): implications for weed biocontrol

Abstract In weed biocontrol, similarity of abiotic factors between the native and introduced range of a biocontrol agent is critical to its establishment and effectiveness. This is particularly the case for weeds that have a wide geographical distribution in the native range. For such weeds, the choice of a specialist insect that has narrow tolerance limits to important abiotic factors can diminish its ability to be an effective biocontrol agent. The membracid Aconophora compressa was introduced in Australia from Mexico for biocontrol of Lantana camara, a plant with a wide climatic tolerance. In this study we investigated the effect of constant and alternating temperatures on A. compressa survival. Longevity of adults and nymphs declined with increasing temperatures, and at 39°C individuals survived for less than a day. At lower temperatures, nymphs survived longer than adults. Survival at alternating temperatures was longer than at constant temperatures, but the general trend of lower survival at higher temperatures remained. Spatially and temporally, the climatic tolerance of A. compressa appears to be a subset of that of lantana, thereby limiting its potential impact.

Development of cat's claw creeper leaf-tying moth Hypocosmia pyrochroma (Lepidoptera: Pyralidae) at different temperatures: Implications for establishment as a biological control agent in Australia and South Africa

The leaf-tying moth Hypocosmia pyrochroma Jones (Lepidoptera: Pyralidae), a native of sub tropical South America, has been introduced as a biological control agent for cat’s claw creeper, Dolichandra unguis-cati (L.) Lohman (Bignoniaceae), in Australia and South Africa. So far there has been no evidence of its field establishment in either country. A narrow temperature tolerance is a potential limiting factor for the establishment of weed biological control insects in novel habitats. In this study, we evaluated the effect of seven constant temperatures (12–40 °C) on the survival and development of H. pyrochroma in temperature-controlled cabinets. Temperatures between 20 and 30 °C were the most favorable for adult survival, oviposition, egg hatching, and larval and pupal development. Adult survival (12–40 °C) and egg development (15–35 °C) showed tolerance for wider temperature ranges than oviposition, and larval and pupal development, which were all negatively affected by both high (>30 °C) and low (<20 °C) temperatures. The degree-day (DD) requirement to complete a generation was estimated as 877 above a threshold temperature of 12 °C. Based on DD requirements and an obligatory winter diapause of pupae from mid-autumn to mid-spring, the potential number of generations (egg to adult) the leaf-tying moth can complete in a year in Australia or South Africa range from one to three. A climate-matching model predicted that the inland regions of both Australia and South Africa are less favorable for H. pyrochroma than the coastal areas. The study suggested that H. pyrochroma is more likely to establish in the coastal areas of Australia where most of the cat’s claw creeper infestations occur, than in South Africa where most of the cat’s claw creeper infestations are inland.

Biology, ecology and conservation of the Mobulidae

The Mobulidae are zooplanktivorous elasmobranchs comprising two recognized species of manta rays (Manta spp.) and nine recognized species of devil rays (Mobula spp.). They are found circumglobally in tropical, subtropical and temperate coastal waters. Although mobulids have been recorded for over 400 years, critical knowledge gaps still compromise the ability to assess the status of these species. On the basis of a review of 263 publications, a comparative synthesis of the biology and ecology of mobulids was conducted to examine their evolution, taxonomy, distribution, population trends, movements and aggregation, reproduction, growth and longevity, feeding, natural mortality and direct and indirect anthropogenic threats. There has been a marked increase in the number of published studies on mobulids since c. 1990, particularly for the genus Manta, although the genus Mobula remains poorly understood. Mobulid species have many common biological characteristics although their ecologies appear to be species-specific, and sometimes region-specific. Movement studies suggest that mobulids are highly mobile and have the potential to rapidly travel large distances. Fishing pressure is the major threat to many mobulid populations, with current levels of exploitation in target fisheries unlikely to be sustainable. Advances in the fields of population genetics, acoustic and satellite tracking, and stable-isotope and fatty-acid analyses will provide new insights into the biology and ecology of these species. Future research should focus on the uncertain taxonomy of mobulid species, the degree of overlap between their large-scale movement and human activities such as fisheries and pollution, and the need for management of inter-jurisdictional fisheries in developing nations to ensure their long-term sustainability. Closer collaboration among researchers worldwide is necessary to ensure standardized sampling and modelling methodologies to underpin global population estimates and status.

Mitochondrial DNA diversity of Cleruchoides noackae (Hymenoptera: Mymaridae): a potential biological control agent for Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae)

Carpintero and Dellap, (Hemiptera: Thaumastocoridae) is a native Australian sap-feeding insect that has become invasive and seriously damaging to commercially grown in the Southern Hemisphere. Lin and Huber (Hymenoptera: Mymaridae) was recently discovered as an egg parasitoid of the Thaumastocoridae in Australia. Mitochondrial DNA (mtDNA; cytochrome oxidase subunit I, COI) sequence diversity amongst 104 individuals from these native populations revealed 24 sequence haplotypes. The COI haplotypes of individuals collected from the Sydney and Southeast Queensland clustered in distinct groups, indicating limited spread of the insect between the regions. Individuals collected from Perth in Western Australia were represented by four COI haplotypes. Although this population is geographically more isolated from other populations, two COI haplotypes were identical to haplotypes found in the Sydney region. The results suggest that has recently been introduced into Perth, possibly from the Sydney area. The high mtDNA diversity and limited spread that is suggested for is in contrast to the lack of geographic associated mtDNA diversity and extensive spread of . If implemented as a biological control agent, this factor will need to be considered in collecting and releasing .

Efficacy of Rhipicephalus (Boophilus) microplus Bm86 against Hyalomma dromedarii and Amblyomma cajennense tick infestations in camels and cattle

The recombinant Bm86-based tick vaccines have shown their efficacy for the control of cattle ticks, Rhipicephalus (Boophilus) microplus and R. annulatus infestations. However, cattle ticks often co-exist with multi-host ticks such as Hyalomma and Amblyomma species, thus requiring the control of multiple tick infestations for cattle and other hosts. Vaccination trials using a R. microplus recombinant Bm86-based vaccine were conducted in cattle and camels against Hyalomma dromedarii and in cattle against Amblyomma cajennense immature and adult ticks. The results showed an 89% reduction in the number of H. dromedarii nymphs engorging on vaccinated cattle, and a further 32% reduction in the weight of the surviving adult ticks. In vaccinated camels, a reduction of 27% and 31% of tick engorgement and egg mass weight, respectively was shown, while egg hatching was reduced by 39%. However, cattle vaccination with Bm86 did not have an effect on A. cajennense tick infestations. These results showed that Bm86 vaccines are effective against R. microplus and other tick species but improved vaccines containing new antigens are required to control multiple tick infestations. (C) 2012 Elsevier Ltd. All rights reserved.

Postharvest physiology and volatile production by flowers of Ptilotus nobilis

Ptilotus nobilis (Lindl.) F. Muell. has potential in the floriculture industries as a cut flower crop. Ethylene production and respiration rates, fresh weight changes and volatile scent production from cut inflorescences of P. nobilis cultivars Passion (dark pink flowers) and Purity (white-green flowers) were measured during vase life. Inflorescence weight loss was significant (P<0.001) during vase life with wilting and colour loss being the primary reasons for loss of vase life. Inflorescences ready for the cut market stored and at 22 degrees C had vase lives of >12 d. Ethylene production by inflorescences was low to negligible. Treatment with silverthiosulphate (STS) and ethylene had no effects on vase life. Evidently, ethylene did not play a role in determining the postharvest longevity of cut P. nobilis flowers. Respiration rates of inflorescences were high at harvest (>700 mg CO2 kg(-1) FW h(-1)) and declined gradually there-after during vase life. Total volatile emissions followed a similar pattern. For Passion, respiration rates of immature florets were significantly greater (P=0.02) than florets from other developmental stages while the calyx produced the most CO2. For Purity, respiration rates of florets of different maturities did not differ and the reproductive tissue produced the most CO2. Only fully opened mature florets with their stigma and anthers revealed, emitted significant quantities of volatiles (P<0.001) and primarily from the calyx tissue for both cultivars. The individual volatiles differed somewhat for the two cultivars. However, both produced significant quantities of benzaldehyde, 3,5-dimethoxytoluene and benzyl alcohol. These. compounds have previously been associated with desirable floral scent. (C) 2013 Elsevier B.V. All rights reserved.

Vitamin A economy of the developing chick embryo and of the freshly hatched chick

. The changes in the net amounts of retinol, retinyl esters and retinal in both the developing chick embryo and the newly hatched chick were investigated. The embryo requires about 68nmol of the vitamin for its growth, whereas the baby chick requires about 108nmol during the first 7 days after hatching. 2. Retinal was present in the egg in fairly high concentrations at the beginning of the incubation but it virtually disappeared from the extra-embryonic tissue after day 17 of incubation. It was not found in the liver of the embryo or of the newly hatched chick up until day 7.

Development of cat’s claw creeper leaf-tying moth Hypocosmia pyrochroma (Lepidoptera: Pyralidae) at different temperatures: Implications for establishment as a biological control agent in Australia and South Africa

The leaf-tying moth Hypocosmia pyrochroma Jones (Lepidoptera: Pyralidae), a native of sub tropical South America, has been introduced as a biological control agent for cat’s claw creeper, Dolichandra unguis-cati (L.) Lohman (Bignoniaceae), in Australia and South Africa. So far there has been no evidence of its field establishment in either country. A narrow temperature tolerance is a potential limiting factor for the establishment of weed biological control insects in novel habitats. In this study, we evaluated the effect of seven constant temperatures (12–40 °C) on the survival and development of H. pyrochroma in temperature-controlled cabinets. Temperatures between 20 and 30 °C were the most favorable for adult survival, oviposition, egg hatching, and larval and pupal development. Adult survival (12–40 °C) and egg development (15–35 °C) showed tolerance for wider temperature ranges than oviposition, and larval and pupal development, which were all negatively affected by both high (>30 °C) and low (<20 °C) temperatures. The degree-day (DD) requirement to complete a generation was estimated as 877 above a threshold temperature of 12 °C. Based on DD requirements and an obligatory winter diapause of pupae from mid-autumn to mid-spring, the potential number of generations (egg to adult) the leaf-tying moth can complete in a year in Australia or South Africa range from one to three. A climate-matching model predicted that the inland regions of both Australia and South Africa are less favorable for H. pyrochroma than the coastal areas. The study suggested that H. pyrochroma is more likely to establish in the coastal areas of Australia where most of the cat’s claw creeper infestations occur, than in South Africa where most of the cat’s claw creeper infestations are inland.

Cu2+ inhibition of gel secretion in the xylem and its potential implications for water uptake of cut Acacia holosericea stems

Maintaining a high rate of water uptake is crucial for maximum longevity of cut stems. Physiological gel/tylosis formation decreases water transport efficiency in the xylem. The primary mechanism of action for post-harvest Cu2+ treatments in improving cut flower and foliage longevity has been elusive. The effect of Cu2+ on wound-induced xylem vessel occlusion was investigated for Acacia holosericea A. Cunn. ex G. Don. Experiments were conducted using a Cu2+ pulse (5 h, 2.2 mM) and a Cu2+ vase solution (0.5 mM) vs a deionized water (DIW) control. Development of xylem blockage in the stem-end region 10 mm proximal to the wounded stem surface was examined over 21 days by light and transmission electron microscopy. Xylem vessels of stems stood into DIW were occluded with gels secreted into vessel lumens via pits from surrounding axial parenchyma cells. Gel secretion was initiated within 1-2 days post-wounding and gels were detected in the xylem from day 3. In contrast, Cu2+ treatments disrupted the surrounding parenchyma cells, thereby inhibiting gel secretion and maintaining the vessel lumens devoid of occlusions. The Cu2+ treatments significantly improved water uptake by the cut stems as compared to the control. © 2013 Scandinavian Plant Physiology Society.

Life history of Anomalococcus indicus (Hemiptera: Lecanodiaspididae), a potential biological control agent for prickly acacia Vachellia nilotica ssp indica in Australia

Babul scale Anomalococcus indicus Ramakrishna Ayyar, a major pest of Vachellia nilotica (L.f.) P.J.H. Hurter & Mabb. on the Indian subcontinent, has been identified as a potential biocontrol agent for prickly acacia V. nilotica subsp. indica (Benth.) Kyal. & Boatwr. in Australia and was imported from southern India for detailed assessment. The life history of A. indicus under controlled glasshouse conditions was determined as a part of this assessment. Consistent with other scale species, A. indicus has a distinct sexual dimorphism which becomes apparent during the second instar. Females have three instars, developing into sexually mature nymphs after 52 days. The generation time from egg to egg was 89 days. Females are ovoviviparous, ovipositing mature eggs into a cavity underneath their body. An average of 802 +/- 114 offspring were produced per female. Reproductive output was closely associated with female size; larger females produced more than 1200 offspring. Crawlers emerged from beneath the female after an indeterminate period of inactivity. They have the only life stage at which A. indicus can disperse, though the majority settle close to their parent female forming aggregative distributions. In the absence of food, most crawlers died within three days. Males took 62 days to develop through five instars. Unlike females, males underwent complete metamorphosis. Adult males were small and winged, and lived for less than a day. Parthenogenesis was not observed in females excluded from males. The life history of A. indicus allows it to complement other biological control agents already established on prickly acacia in Australia.

Boronia heterophylla vase life is influenced more by ethylene than by bacterial numbers or vase solution pH

Bacterial proliferation in both vase solutions and in cut flower stems has been implicated in reducing the vase life of numerous genera. Boronia heterophylla F. Muell. (Red Boronia) vase life was assessed at two stages of floral maturity for nine vase solution treatments covering a pH range of 2.5-5.7. Vase life for advanced harvest maturity stems ranged from 4.2 d in 10 mM citric acid + 50 mg L-1 chlorine (pH 2.5) to 12.9 d after STS pulsing (pH 5.7). For normal harvest maturity stems, the corresponding range was 5.8-19.0 d, respectively. Vase solutions containing 50 mg L-1 chlorine biocide resulted in decreased longevity. In contrast, pulsing with the ethylene-binding inhibitor, STS, significantly increased vase life. The number of bacteria in the vase solutions after 11 d was determined in stems of advanced maturity. The solution with the greatest number of bacteria, 4.0 x 10(10) cfu mL(-1), was water used after STS pulsing and in which the flowers lasted longest. Vase solution bacteria were enumerated on days 0,3, 6, 9 and 12 of the vase period with stems of normal harvest maturity. There was no relationship between vase life and vase solution bacterial numbers ((R) over bar (2) = 0.000). Moreover, there was a negative relationship between numbers of bacteria in basal 0-5 cm stem segments and vase life. As no correlations were evident between longevity and either the pH or vase solution bacterial numbers, B. heterophylla vase life was evidently limited principally by ethylene action. (C) 2013 Elsevier B.V. All rights reserved.

Rhipicephalus (Boophilus) microplus tick in vitro feeding methods for functional (dsRNA) and vaccine candidate (antibody) screening

Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) ticks cause economic losses for cattle industries throughout tropical and subtropical regions of the world estimated at $US2.5 billion annually. Lack of access to efficacious long-lasting vaccination regimes and increases in tick acaricide resistance have led to the investigation of targets for the development of novel tick vaccines and treatments. In vitro tick feeding has been used for many tick species to study the effect of new acaricides on the transmission of tick-borne pathogens. Few studies have reported the use of in vitro feeding for functional genomic studies using RNA interference and/or the effect of specific anti-tick antibodies. In particular, in vitro feeding reports for the cattle tick are limited due to its relatively short hypostome. Previously published methods were further modified to broaden optimal tick sizes/weights, feeding sources including bovine and ovine serum, optimisation of commercially available blood anti-coagulant tubes, and IgG concentrations for effective antibody delivery. Ticks are fed overnight and monitored for ∼5–6 weeks to determine egg output and success of larval emergence using a humidified incubator. Lithium-heparin blood tubes provided the most reliable anti-coagulant for bovine blood feeding compared with commercial citrated (CPDA) and EDTA tubes. Although >30 mg semi-engorged ticks fed more reliably, ticks as small as 15 mg also fed to repletion to lay viable eggs. Ticks which gained less than ∼10 mg during in vitro feeding typically did not lay eggs. One mg/ml IgG from Bm86-vaccinated cattle produced a potent anti-tick effect in vitro (83% efficacy) similar to that observed in vivo. Alternatively, feeding of dsRNA targeting Bm86 did not demonstrate anti-tick effects (11% efficacy) compared with the potent effects of ubiquitin dsRNA. This study optimises R. microplus tick in vitro feeding methods which support the development of cattle tick vaccines and treatments.

Methods to determine resistance to anthelmintics when continuing larval development occurs

The in vivo faecal egg count reduction test (FECRT) is the most commonly used test to detect anthelmintic resistance (AR) in gastrointestinal nematodes (GIN) of ruminants in pasture based systems. However, there are several variations on the method, some more appropriate than others in specific circumstances. While in some cases labour and time can be saved by just collecting post-drench faecal worm egg counts (FEC) of treatment groups with controls, or pre- and post-drench FEC of a treatment group with no controls, there are circumstances when pre- and post-drench FEC of an untreated control group as well as from the treatment groups are necessary. Computer simulation techniques were used to determine the most appropriate of several methods for calculating AR when there is continuing larval development during the testing period, as often occurs when anthelmintic treatments against genera of GIN with high biotic potential or high re-infection rates, such as Haemonchus contortus of sheep and Cooperia punctata of cattle, are less than 100% efficacious. Three field FECRT experimental designs were investigated: (I) post-drench FEC of treatment and controls groups, (II) pre- and post-drench FEC of a treatment group only and (III) pre- and post-drench FEC of treatment and control groups. To investigate the performance of methods of indicating AR for each of these designs, simulated animal FEC were generated from negative binominal distributions with subsequent sampling from the binomial distributions to account for drench effect, with varying parameters for worm burden, larval development and drench resistance. Calculations of percent reductions and confidence limits were based on those of the Standing Committee for Agriculture (SCA) guidelines. For the two field methods with pre-drench FEC, confidence limits were also determined from cumulative inverse Beta distributions of FEC, for eggs per gram (epg) and the number of eggs counted at detection levels of 50 and 25. Two rules for determining AR: (1) %reduction (%R) < 95% and lower confidence limit <90%; and (2) upper confidence limit <95%, were also assessed. For each combination of worm burden, larval development and drench resistance parameters, 1000 simulations were run to determine the number of times the theoretical percent reduction fell within the estimated confidence limits and the number of times resistance would have been declared. When continuing larval development occurs during the testing period of the FECRT, the simulations showed AR should be calculated from pre- and post-drench worm egg counts of an untreated control group as well as from the treatment group. If the widely used resistance rule 1 is used to assess resistance, rule 2 should also be applied, especially when %R is in the range 90 to 95% and resistance is suspected.