Growth and mortality of sibling triploid and diploid Sydney rock oysters, Saccostrea glomerata (Gould), in the Camden Haven River

Growth and mortality of sibling triploid and diploid Sydney rock oysters, grown at two tidal heights, three stocking densities and three different sites on the Camden Haven River estuary, were compared. Triploids grew faster than diploids. The majority of the growth rate difference occurred after the oysters reached 2 years of age. By 3.2 years, triploids were 49% heavier than diploids. Oysters grown intertidally were larger than those grown subtidally. Oysters stocked at the lightest density of 2 L per basket grew to a significantly larger size than baskets stocked at 3 or 4 L. Growth rates were significantly different at the three sites. Growth was reduced the further the oysters were from the mouth of the estuary. There was no significant difference in mortality between ploidy level, but there were differences between tidal heights, stocking densities and sites. Intertidal oysters suffered higher mortality than subtidal. Oysters stocked at the highest density had a significantly higher mortality than the lowest density; neither of these was significantly different from the medium density. The site closest to the mouth of the estuary had significantly lower mortality than the middle and upper estuary sites.     

Difference in factors explaining growth rate variability in European eel subpopulations: the possible role of habitat carrying capacity

As a key parameter in the management of fish populations, individual growth rate (GR) variations were examined in the European eel (Anguilla anguilla; > 150 mm) using extensive mark–recapture surveys in the lotic habitats of two small rivers of western France: the Frémur, supposed to be saturated, and at the same latitude, the Oir with densities fivefold lower than those of the Frémur. In both systems, generalised linear models were used to test whether spatiotemporal factors such as dominant habitat type or local density affect GR variability. In the presumed unsaturated system, the Oir, GR variability is mainly explained by a set of habitat suitability drivers (density, dominant habitat type). In the Frémur, GRs appear independent of differences in habitat density or productivity. Below saturation, an increase in density will decrease the GR through intraspecific competition. At saturation, intraspecific competition reaches such high levels that regardless of eel density and productivity, the resources available by individual are similar throughout the system. In these circumstances, the effect of density on growth was presumed undetectable. Despite these contrasted results, mean GRs observed in both catchments were closed (~20 mm·year^?1). This is an unexpected result as GR is expected to be higher in unsaturated systems. This similarity could be explained by the difference between the two systems in terms of: (i) sex ratio (the Frémur is dominated by male, whereas the female is dominant in the Oir), (ii) habitat type distribution or (iii) possible interspecific competition (important salmonid populations in the Oir).     

Interactions of insecticides with biological membranes

Many insecticides (e.g. DDT, lindane, pyrethroids) are hydrophobic molecules which bind extensively to biological membranes. Binding of insecticides to phospholipid bilayers frequently shows saturation, with binding increasing with increasing insecticide concentration up to some limit, beyond which no further insecticide is incorporated into the bilayer. For lindane, this limit has been shown to correspond to the concentration at which the aqueous phase becomes saturated. Simple alkanes show similar saturation phenomena, and binding of halogenated alkanes can be followed by fluorescence quenching methods. It is shown that effects of hydrophobic molecules on bilayer fluidity are small. Effects of alkanes and insecticides on the activity of the (Ca²⁺-Mg²⁺)-ATPase purified from sarcoplasmic reticulum follow from direct binding to the ATPase, at sites which are not at the lipid-protein interface of the ATPase.     

The physical and chemical properties of the herbicide cinmethylin (SD 95481)

Cinmethylin (SD 95481), is a novel herbicide developed for the selective pre-emergence control of many annual grass weeds in a wide range of temperate and tropical crops. Representing new herbicide chemistry, cinmethylin is in the cineole family. Cinmethylin is a mobile colourless liquid with a boiling point of 313°C under an inert atmosphere at atmospheric pressure. It has a density of 1015 kg m^?3 and a viscosity of 70–90 mPa s, both at 20°C. It is miscible in all proportions with most organic solvents but has a low solubility, 63 mg litre^?1, in water. It has a vapour pressure of 10.2 mPa (20°C) and the vapour pressure/temperature relationship is given by log_e P(Pa)=28.9–9816/T (K). The n-octanol/water partition coefficient is 6850 and soil organic matter/water sorption coefficient (K_om) ranges between 165 and 235 over the three types of soil used in these studies. Cinmethylin is stable in water over the pH range 3–11. Solutions of cinmethylin in water or solvents are reasonably stable to sunlight, though thin films on a quartz surface photooxidise mainly to an ester within 24 h. This rate can be reduced by the addition of photostabilisers or by sorption onto soil surfaces. In an inert atmosphere cinmethylin is stable to high temperatures, though, in air, oxidation occurs at temperatures above 100°C to give the same product as by photodecay.     

Evaluation of PCR,IEF and ELISA techniques for the detection and identification of potato cyst nematodes from field soil samples in England and Wales

Effective management of potato cyst nematodes (PCNs) requires simple, rapid and accurate identification and quantification of field populations. Soil samples from a survey of 484 fields in potato rotations in England and Wales were used to compare the identification and quantification of PCNs using IEF, PCR, ELISA and bait plant tests. The cyst counts and bait plant test revealed that 64.3% of field samples contained PCNs. Bait plant tests increased the detection rate of PCNs in field samples by 4–6.4%. This means that some infestations are cryptic and would not normally be detected by standard counts. IEF, PCR and ELISA methods distinguished between Globodera rostochiensis and G pallida and were able to register mixed populations; however they were not in full agreement. All methods suggested that G pallida is the dominant species in the field samples tested. The PCR results indicated that 66% of field samples contained pure G pallida, 8% contained pure G rostochiensis and 26% contained mixtures of the two species. Estimates of the relative process times taken per sample in the PCR, IEF and ELISA techniques are given. © 2001 Society of Chemical Industry     

NOCTURNAL ACTIVITY OF BIRDS ON SHRIMP MARICULTURE PONDS

Birds can reduce production of shrimp in mariculture grow-out ponds through predation and competition for feed. This study involved weekly nocturnal enumeration of bird populations and observation of nocturnal avian habits on a series of 0.1 ha experimental ponds at the Texas A&M University Shrimp Mariculture Facility at Corpus Christi, Texas. Observations were conducted hourly from sunset to sunrise during October through December 1980. The rate of predation was evaluated every three hours by comparing the number of feeding attempts to the number of successful prey captures over a known time period. Gulls (Family Laridae) acted primarily as competitors for feed. Active feeding by gulls was restricted to daylight hours, consequently feed loss decreased when the feed was distributed at or after dusk. Major preadatory birds included herons and egrets (F. Ardeidae), migratory ducks (F. Anatidae), and, to a lesser extent, grebes (F. Podicipedidae) and shorebirds (Order Charadriiformes). Bird predation decreased pond production by 75% in some ponds.     

Leptospirosis in dogs: a serologic survey and case series 1996 to 2001

All leptospirosis microscopic agglutination test titers for the Leptospira serovars icterohaemorrhagiae, canicola, grippotyphosa, bratislava, hardjo, and pomona conducted on 1,260 blood samples from dogs at the University of Illinois Veterinary Diagnostic Laboratory between March 1996 and March 2001 were evaluated. Low titers (1:100 to 1:400) were predominantly L. icterohaemorrhagiae and L. canicola, which represented the predominant serovars (65.4%) among all positive samples with low titers. L. grippotyphosa was the predominant serovar (72.1%) among samples with clinically significant titers (greater than 1:800). The medical records of 87 dogs with a titer greater than 1:800 that were patients at the Veterinary Teaching Hospital of the University of Illinois were reviewed. A clinical diagnosis of leptospirosis was made in 15 cases (17.2%) based on the elevated titer, appropriate clinical signs, lack of recent vaccination, and lack of concurrent disease that could explain the clinical signs present. Renal disease was present in 10 of the cases, concurrent renal and hepatic disease in two, and hepatic disease in three. In 12 cases, the predominant serovar was L. grippotyphosa; titers to L. grippotyphosa and L. bratislava were equal in magnitude in three cases.     

Leptospirosis in dogs: a serologic survey and case series 1996 to 2001

All leptospirosis microscopic agglutination test titers for the Leptospira serovars icterohaemorrhagiae, canicola, grippotyphosa, bratislava, hardjo, and pomona conducted on 1,260 blood samples from dogs at the University of Illinois Veterinary Diagnostic Laboratory between March 1996 and March 2001 were evaluated. Low titers (1:100 to 1:400) were predominantly L. icterohaemorrhagiae and L. canicola, which represented the predominant serovars (65.4%) among all positive samples with low titers. L. grippotyphosa was the predominant serovar (72.1%) among samples with clinically significant titers (greater than 1:800). The medical records of 87 dogs with a titer greater than 1:800 that were patients at the Veterinary Teaching Hospital of the University of Illinois were reviewed. A clinical diagnosis of leptospirosis was made in 15 cases (17.2%) based on the elevated titer, appropriate clinical signs, lack of recent vaccination, and lack of concurrent disease that could explain the clinical signs present. Renal disease was present in 10 of the cases, concurrent renal and hepatic disease in two, and hepatic disease in three. In 12 cases, the predominant serovar was L. grippotyphosa; titers to L. grippotyphosa and L. bratislava were equal in magnitude in three cases.     

The effect of topical tripeptide-copper complex on healing of ischemic open wounds

OBJECTIVE: To evaluate the effects of topical glycyl-L-histidyl-L-lysine tripeptide-copper complex (TCC; Iamin 2% Gel; Procyte Corporation, Redmond, WA) on healing in ischemic open wounds. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Twenty-four adult male Sprague-Dawley rats. METHODS: Rats were divided into 3 groups: topical TCC, topical TCC vehicle (hydroxypropyl-methylcellulose), and no treatment (control). Six-mm-diameter, full-thickness wounds were created within an ischemic bipedicle skin flap on the dorsum of each rat. Each day, for 13 days, wound margins were traced, and the TCC and TCC vehicle groups were treated topically. Tracings were scanned, and wound perimeter and area were calculated. On days 6, 10, and 13, selected wounds were biopsied and analyzed for tumor necrosis factor alpha (TNF-alpha) and matrix metalloproteinases (MMP) 2 and 9. RESULTS: A significant decrease in wound area was seen in the TCC group, but not the vehicle group, when compared with the control group on days 3 to 5, 6 to 9, and 11 to 13 and when TCC was compared with TCC vehicle on days 3 and 9. On day 13, initial wound area had decreased by 64.5% in the TCC group, 45.6% in the vehicle group, and 28.2% in the control group. On days 6, 10, and 13, TCC-treated wounds contained significantly lower concentrations of TNF-alpha and MMP-2 and MMP-9 than control wounds. CONCLUSION: Topical TCC resulted in accelerated wound healing in ischemic open wounds. CLINICAL RELEVANCE: Topical TCC is an effective stimulant of healing of ischemic open wounds in rats and may have an application for the treatment of chronic wounds in other species. Clinical evaluation of topical TCC is warranted.