Influence of spawning procedure on gametes fertilization success in Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae): Implications for the conservation of this species

Artificial reproduction and gamete fertilization were evaluated in Salminus hilarii wild and domesticated broodstocks. Wild and domesticated broodstocks were artificially induced to reproduction using a carp pituitary treatment. Four groups were considered: Group 1 (G1), fish caught in the wild maintained for three years in the same conditions as the domesticated broodstocks and spawned naturally; Group 2 (G2), broodstock born and raised in captivity and spawned naturally; Group 3 (G3), wild broodstocks, which were manually stripped for gamete collection and dry fertilization; and Group 4 (G4), domesticated males and females, also manually stripped. Oocytes, eggs, and larvae were sampled at different time intervals throughout embryonic development. Yolk sac absorption occurred approximately 24-29 h after hatching. Twenty-six h after hatching, the larvae mouths opened. Cannibalism was identified just 28-30 h after hatching. There was no morphological difference in embryonic development among all groups. The number of released eggs per gram of female was: G1: 83.3 ± 24.5 and G2: 103.8 ± 37.4; however, the fertilization success was lower in G2 (42.0 ± 6.37 %) compared with G1 (54.7 ± 3.02%) (P = 0.011). Hand-stripping of oocytes was not successful and the fertilization rate was zero. The reproduction of this species in captivity is viable, but it is necessary to improve broodstock management to enhance fertilization rates and obtain better fingerling production for restocking programs.

Effect of Hormonal Supplementation Periods and In Vitro Maturation Media on Developmental Competence of Pig Oocytes

Background: The oocyte ability to undergo successful fertilization, cleavage and embryonic development depends on meiotic maturation and developmental competence acquisition. In vitro maturation (IVM) protocols currently use eCG, hCG or a combination of both, the effect of these gonadotrophins during IVM and subsequent embryonic development is still controversial. Several media have been used for IVM of porcine oocytes: TCM199, Whitten's and NCSU23 have also been shown to support pig oocyte IVM. This study was designed to determine the effect of hormonal supplementation period and maturation media during in vitro maturation of pig oocytes (1) and subsequent embryonic development (2). Materials, Methods & Results: Oocytes with intact cumulus oophurus layers and homogeneous cytoplasm were collected from prebubertal gilts. IVM was subjected in NCSU23, TCM199 or Whitten's media supplemented with 10 IU/mL eCG and 10 IU/mL hCG for the first 24 or 48 h of IVM. In each replicate the oocytes were fixed every 4 h from 32 to 48 h IVM or the past 48 h after IVM, oocytes were fertilized in vitro in mTBM medium for six hours and cultured in NCSU23 medium for nine days. Cleavage, blastocyst and hatching rates were evaluated at 48 h (day 2), 168 h (day 7) and 216 h (day 9), respectively. The addition of eCG and hCG during the first 24 h IVM increased the proportion of oocytes that reached MII stage at 44 h of maturation in NCSU23 medium. This effect was also observed in Whitten medium at 44 and 48 h (P < 0.05). However, it was not observed in the TCM199 medium. No effect of maturation medium on oocyte nuclear maturation (P > 0.05) was observed in oocytes matured in the presence of eCG and hCG during the first 24 h IVM or during 48 h IVM. A progressive increase of maturation indexes was observed on oocytes matured with hormonal supplementation in Whitten media for 24 h. Higher indexes were obtained at 44 and 48 h. When NCSU23 media was used, no difference after 36 h of maturation was observed. The same result was observed in TCM199. A progressive increase of maturation indexes was observed on oocytes matured with hormonal supplementation for 48 h in Whitten media. Higher indexes were obtained in 36 and 40 h. When NCSU23 or TCM199 were used, no difference was observed. No effect of IVM media on the percentage of fertilized oocytes and polyspermic oocytes or number of spermatozoa per fertilized oocytes was observed. Also, no effect of IVM media on cleavage and blastocyst rates was seen. However, the proportion of hatched blastocysts was lower in NCSU23 compared to Whitten or TCM199. Discussion: Similar results were reported by Marques et al. [13], that it no differences between hormonal supplementation for 22 or 44 h were observed. Therefore, more studies are needed to elucidate the role of these hormones in nuclear in vitro maturation in pig oocytes. In conclusion, no effect of maturation media on meiotic progression was observed. However, the proportion of oocytes that reached metaphase II (MII) stage was higher when eCG + hCG were added for 24 h than 48 h mainly at the 44 h of maturation. In addition, no differences were observed in cleavage and blastocyst rates of the cultured embryos. However, embryos cultured in NCSU23 showed lower rates of hatching compared to other media. These results indicated no effect of maturation media on the fertilization and embryonic development even in the presence of cysteine, PFF and EGF, except for hatched embryos that these rates were lower in NCSU23.

Endophytic and entomopathogenic strains of Beauveria sp to control the bovine tick Rhipicephalus (Boophilus) microplus

Pathogenicity of strains of the entomopathogenic fungus Beauveria bassiana and endophytic strains of Beauveria sp against the bovine tick Rhipicephalus (Boophilus) microplus was tested in laboratory bioassays and under field conditions. Suspensions containing 10(5), 10(7) and 10(9) conidia/mL were prepared of each fungal strain for laboratory bioassays. The ticks were maintained at 28 degrees C, 90 +/- 5% relative humidity, and the following variables were evaluated: initial female weight, egg weight, hatching percentage, reproductive efficiency, and percentage control. For tests under field conditions, a Beauveria suspension containing 10(6) conidia/mL was sprayed on tick-infested cows. After 72 h, the ticks were collected to estimate mortality under field conditions. Laboratory bioassays showed a mortality of 20 to 50% of the ticks seven days after inoculation with 10(7) Beauveria conidia/mL. Under field conditions 10(6) Beauveria conidia/mL induced 18-32% mortality. All Beauveria strains were effective in biological control of R. (Boophilus) microplus under laboratory and field test conditions. This is the first demonstration that endophytic fungi can be used for biological control of the cattle tick; this could help reduce environmental contamination by diminishing the need for chemical acaricides. Two endophytic strains were isolated from maize leaves and characterized by molecular sequencing of 5.8S rDNA ITS1 and ITS2 and morphological analyses of conidia. We found that these two endophytic Beauveria isolates, designated B95 and B157, are close to Beauveria amorpha.

Tidal-amplitude rhythms of larval release: variable departure from presumed optimal timing among populations of the mottled shore crab

It is widely assumed that optimal timing of larval release is of major importance to offspring survival, but the extent to which environmental factors entrain synchronous reproductive rhythms in natural populations is not well known. We sampled the broods of ovigerous females of the common shore crab Pachygrapsus transversus at both sheltered and exposed rocky shores interspersed along a so-km coastline, during four different periods, to better assess inter-population differences of larval release timing and to test for the effect of wave action. Shore-specific patterns were consistent through time. Maximum release fell within 1 day around syzygies on all shores, which matched dates of maximum tidal amplitude. Within this very narrow range, populations at exposed shores anticipated hatching compared to those at sheltered areas, possibly due to mechanical stimulation by wave action. Average departures from syzygial release ranged consistently among shores from 2.4 to 3.3 days, but in this case we found no evidence for the effect of wave exposure. Therefore, processes varying at the scale of a few kilometres affect the precision of semilunar timing and may produce differences in the survival of recently hatched larvae. Understanding the underlying mechanisms causing departures from presumed optimal release timing is thus important for a more comprehensive evaluation of reproductive success of invertebrate populations.

Influence of egg pre-storage heating period and storage length on incubation results

This experiment aimed at evaluating the influence of different heating times of settable eggs of Cobb 500 (R) broiler breeders before submitting them to different storage periods on egg weight loss, embryo mortality, and hatchability. A total number of 1,980 eggs were distributed in a completely randomized experimental design with a 3 x 3 factorial arrangement, comprising nine treatments with 22 replicates of 10 eggs each. The following factors were analyzed: pre-storage heating periods (0, 6, 12 hours at 36.92 degrees C) and storage periods (4, 9, 14 days at 12.06 degrees C). After storage, eggs were incubated under usual conditions, and were transferred to the hatcher at 442 hours of incubation. Eggs were weighed before heating, incubation, and transference to determine weight loss. Partial hatchability was determined at 480 hours, and total hatchability at 498 hours of incubation. Embryo mortality was determined in non-hatched eggs. It was concluded that heating eggs for six hour before storage improves incubation results as it decreases incubation length and late embryo mortality, therefore its use can be indicated in commercial operations. Storing eggs for 14 days and pre-heating for 14 days and pre-heating for 12 hours severely impair incubation results, and therefore are not recommended.

Influence of egg pre-storage heating period and storage length on the digestive tract of newly-hatched broiler chicks

An experiment was carried out to evaluate the effect of different heating times of settable eggs of Cobb 500 (R) broiler breeders before submitting them to different storage periods on body weight, digestive tract organ weights, and intestinal mucosa morphology of newly-hatched chicks. Settable eggs were distributed in a completely randomized experimental design with a 3 x 3 factorial arrangement: pre-storage heating periods (0, 6, 12 hours at 36.92 degrees C) and storage periods (4, 9, 14 days at 12.06 degrees C). Body weight and relative weights of the yolk sac, heart, liver, proventriculus+gizzard, and intestinal segments were measured in chicks hatching at 480 and 498 hours of incubation. Villi height, width and perimeter, and crypt depth < im) were measured in duodenal histological sections. It was concluded that pre-storage healing for six hours of eggs stored for four or nine days increases small intestine weight of newly-hatched chicks, but does not influence the morphology of the duodenal mucosa. Pre-storage heating for 12 hours negatively influences body weight and duodenal mucosa development, and therefore this practice is not recommended. Storage length does not have consistent effect on body weight and development of the gastrointestinal tract.

Incubation of turtle eggs at different temperatures: Do embryos compensate for temperature during development?

Freshwater turtle eggs are normally subjected to fluctuations in incubation temperature during natural incubation. Because of this, developing embryos may make physiological adjustments to growth and metabolism in response to incubation at different temperatures. I tested this hypothesis by incubating eggs of the Brisbane river turtle Emydura signata under four different temperature regimes, constant temperatures of 24 degrees C and 31 degrees C throughout incubation, and two swapped-temperature treatments where incubation temperature was changed approximately halfway through incubation. Incubation at 31 degrees C took 42 d, and incubation at 24 degrees C look 78 d, with intermediate incubation periods for the swapped-temperature treatments. Hatchling mass, hatchling size, and total oxygen consumed during development were similar for all incubation regimes. The pattern of oxygen consumption during the last phase of incubation as reflected by rate of increase of oxygen consumption, peak oxygen consumption, and fall in oxygen consumption before hatching was determined solely by the incubation temperature during the last phase of incubation; that is, incubation temperature during the first phase of incubation had no influence on these factors. Thus there is no evidence of temperature compensation in growth or development during embryonic development of E. signata eggs.

Ontogenetic changes in the retinal photoreceptor mosaic in a fish, the black bream, Acanthopagrus butcheri

The morphological development of the photoreceptor mosaic was followed by light and electron microscopy in a specific region of dorsal retina of the black bream, Acanthopagrus butcheri (Sparidae, Teleostei), from hatching to eight weeks of age. The retina was differentiated when the larvae reached a total length of 3 mm (3-5 days posthatch). Single cones, arranged in tightly packed rows, were the only morphologically distinct type of photoreceptor present until the larvae were 6 mm (day 15) in standard length (SL). At this time, the rad nuclei had become differentiated and the ellipsoids of selected cones began to form subsurface cisternae along neighbouring cone membranes. In this way, double, triple, quadruple, and occasionally photoreceptor chains of up to 10 cones were formed. At 8 mm SL, there was little apparent order in the photoreceptor mosaic. However, concomitant with subsequent growth, quadruple and other multiple cone receptors disappeared, with the exception of the triple cones, which gradually reduced in both number and retinal coverage to be restricted to central retina by 15 mm SL (days 40-55). Following this stage, the arrangement of double and single cones peripheral to the region of triple cones in dorsal retina was transformed into the adult pattern of a regular mosaic of four double cones surrounding a single cone. These results demonstrate that an established photoreceptor mosaic of rows of single cones can be reorganised to form a regular square mosaic composed of single and double cones. J. Comp. Neural. 412:203-217, 1999. (C) 1999 Wiley-Liss, Inc.

Moisture is required for the termination of egg diapause in the chrysomelid beetle, Homichloda barkeri

Four factors (moisture, light regime, temperature, food type) were examined for their effects on the embryonic diapause of Homichloda (Weiseana) barkeri (Jacoby) (Coleoptera: Chrysomelidae), a biocontrol agent for prickly acacia, Acacia nilotica (L.) Willdenew ex Delile (Mimosaceae). Moisture is critical for termination of diapause. A single wetting of eggs resulted in a low hatch rate while a sequence of wetting events followed by periods of dryness produced a high hatch rate. A relatively constant proportion of embryos within each batch initiated development at each wetting event, with hatching complete after the eighth wetting event in these trials. An extended interval between wetting events, tested at up to 23 days, did not result in a decreased overall hatch rate. A threshold time of exposure to moisture of between 3 to 6 h is required before development proceeds. The response of eggs to the moisture regime is seen as a strategy for taking advantage of available food after rainfall by terminating diapause, rather than merely a quiescent response to the absence of moisture. Temperature affected development time and the proportion of eggs that developed. Experimental manipulations of photoperiod and host-plant availability showed no effect on embryonic development.

Life tables of the processionary caterpillar Ochrogaster lunifer Herrich-Schaffer (Lepidoptera : Thaumetopoeidae) at local and regional scales

A major ongoing debate in population ecology has surrounded the causative factors underlying the abundance of phytophagous insects and whether or not these factors limit or regulate herbivore populations. However, it is often difficult to identify mortality agents in census data, and their distribution and relative importance across large spatial scales are rarely understood. Were, we present life tables for egg batches and larval cohorts of the processionary caterpillar Ochrogaster lunifer Herrich-Schaffer, using intensive local sampling combined with extensive regional monitoring to ascertain the relative importance of different mortality factors at different localities. Extinction of entire cohorts (representing the entire reproductive output of one female) at natural localities was high, with 82% of the initial 492 cohorts going extinct. Mortality was highest in the egg and early instar stages due to predation from dermestid beetles, and while different mortality factors (e.g. hatching failure, egg parasitism and failure to establish on the host) were present at many localities, dermestid predation, either directly observed or inferred from indirect evidence, was the dominant mortality factor at 89% of localities surveyed. Predation was significantly higher in plantations than in natural habitats. The second most important mortality factor was resource depletion, with 14 cohorts defoliating their hosts. Egg and larval parasitism were not major mortality agents. A combination of predation and resource depletion consistently accounted for the majority of mortality across localities, suggesting that both factors are important in limiting population abundance. This evidence shows that O. lunifer is not regulated by natural enemies alone, but that resource patches (Acacia trees) ultimately, and frequently, act together to limit population growth.

Inhibition of settlement and metamorphosis of the ascidian Herdmania curvata by non-geniculate coralline algae

The surfaces of non-geniculate coralline algae (NCA) are known to induce the settlement and metamorphosis of disparate marine taxa. In this study we investigate the responsiveness of larvae of Herdmania curvata (Ascidiacea: Stolidobranchia) to three species of NCA (Neo-goniolithon brassica-florida, Hydrolithon onkodes, and Lithothamnium prolifer) that cohabit the slope and crest of Heron Reef, Great Barrier Reef. H. curvata larvae were first exposed to these NCA at or within 2 h of hatching, which is 1 to 2 h prior to attaining competence, and then cultured continuously with the NCA for 12 to 14 h. Rates of settlement and metamorphosis of H, curvata cultured in laboratory chambers in the presence of the different NCA were significantly lower than spontaneous rates in seawater. The limited settlement in treatments containing NCA were confined entirely to the chamber periphery, and settlement never occurred on the surface of the NCA. The inhibitory effect was dose-dependent and was stronger in H. brassica-florida and H. onkodes than in L. prolifer. Larvae that did not settle in treatments with NCA had rounded anterior trunks and, in extreme cases, kinked tails with rounded and dissociated tail muscle cells. In some individuals, we observed the anterior chemosensory papillae being sloughed off the larval body. Morphological analysis of trunk ectodermal and mesenchymal nuclei of larvae cultured in the presence of the NCA revealed that general necrotic cell death was occurring. Importantly, H. curvata larvae that were exposed to NCA could not subsequently be induced to metamorphose in KCl-elevated seawater, whereas larvae not exposed to NCA metamorphosed at high rates in KCl-elevated seawater.

Foraging and vein-cutting behaviour of Euploea core corinna (W.S. Macleay) (Lepidoptera : Nymphalidae) caterpillars feeding on latex-bearing leaves

Caterpillars of Euploea core corinna (W. S. Macleay) sever leaf veins prior to feeding on their latex-bearing host plants, which restricts the flow of latex at feeding sites. The severing of leaf veins by insects feeding on latex-bearing plants is commonly referred to as 'sabotaging' and is thought to be an evolved response by the insect to counter the negative effects of feeding on latex-rich leaves. Sabotaging behaviour is described for all instars of E. core corinna, with particular attention given to neonates. Vein cutting by neonate E. core corinna caterpillars can occur within 2 h of hatching, with most caterpillars establishing feeding sites within 10 h. Commonly, first instars cut an are-shaped row of leaf side-veins parallel to the leaf margin, but they may also cut the leaf mid-rib in a fashion similar to older instar larvae. From a sample of 50 E. core corinna larvae, representing all instars, we found that the diameters of the veins cut by caterpillars are closely correlated to larval head width (r=0.90). Through manipulative experiments, we demonstrate for the first time that sabotaging behaviour in neonate caterpillars imposes no detectable short-term physiological costs on those caterpillars.

Sperm environment affects offspring quality in broadcast spawning marine invertebrates

The provisioning of offspring can have far-reaching consequences for later life in a wide range of organisms and generally this provisioning is thought to be under maternal influence or control. In experiments with a broadcast-spawning ascidian, we found that the size of offspring was determined by egg size and the abundance of sperm present during fertilization. Larger eggs were fertilized at low sperm concentrations, whilst smaller eggs were successfully fertilized at high sperm concentrations. These differences in fertilized egg size resulted in differences in the development rate, hatching success and mean size of the subsequent larvae. Our results suggest that, in contrast to females that reproduce by other mating systems, free-spawning mothers lack some control over the provisioning of offspring. Furthermore, because males can alter the sperm environment, they can exert paternal (non-genetic) control over key offspring characteristics.

Standard Values for Real-Time Transthoracic Three-Dimensional Echocardiographic Dyssynchrony Indexes in a Normal Population

Background: There is a paucity of information describing the real-time 3-dimensional echocardiography (RT3DE) and dyssynchrony indexes (DIs) of a normal population. We evaluate the RT3DE DIs in a population with normal electrocardiograms and 2- and 3-dimensional echocardiographic analyses. This information is relevant for cardiac resynchronization therapy. Methods: We evaluated 131 healthy volunteers (73 were male, aged 46 +/- 14 years) who were referred for routine echocardiography; who presented normal cardiac structure on electrocardiography, 2-dimensional echocardiography, and RT3DE; and who had no history of cardiac diseases. We analyzed 3-dimensional left ventricular ejection fraction, left ventricle end-diastolic volume, left ventricle end-systolic volume, and left ventricular systolic DI% (6-, 12-, and 16-segment models). RT3DE data were analyzed by quantifying the statistical distribution (mean, median, standard deviation [SD], relative SD, coefficient of skewness, coefficient of kurtosis, Kolmogorov-Smirnov test, D`Agostino-Pearson test, percentiles, and 95% confidence interval). Results: Left ventricular ejection fraction ranged from 50% to 80% (66.1% +/- 7.1%); left ventricle end-diastolic volume ranged from 39.8 to 145 mL (79.1 +/- 24.9 mL); left ventricle end-systolic volume ranged from 12.9 to 66 mL (27 +/- 12.1 mL); 6-segment DI% ranged from 0.20% to 3.80% (1.21% +/- 0.66%), median: 1.06, relative SD: 0.5482, coefficient of skewness: 1.2620 (P < .0001), coefficient of Kurtosis: 1.9956 (P = .0039); percentile 2.5%: 0.2900, percentile 97.5%: 2.8300; 12-segment DI% ranged from 0.22% to 4.01% (1.29% +/- 0.71%), median: 1.14, relative SD: 0.95, coefficient of skewness: 1.1089 (P < .0001), coefficient of Kurtosis: 1.6372 (P = .0100), percentile 2.5%: 0.2850, percentile 97.5%: 3.0700; and 16-segment DI% ranged from 0.29% to 4.88% (1.59 +/- 0.99), median: 1.39, relative SD: 0.56, coefficient of skewness: 1.0792 (P < .0001), coefficient of Kurtosis: 0.9248 (P = .07), percentile 2.5%: 0.3750, percentile 97.5%: 3.750. Conclusion: This study allows for the quantification of RT3DE DIs in normal subjects, providing a comparison for patients with heart failure who may be candidates for cardiac resynchronization therapy. (J Am Soc Echocardiogr 2008; 21: 1229-1235)

Induction of metamorphosis with potassium ions requires development of competence and an anterior signalling centre in the ascidian Herdmania momus

Increased Kt concentration in seawater induces metamorphosis in the ascidian Herdmania momus. Larvae cultivated at 24 degrees C exhibit highest rates of metamorphosis when treated with 40 mM KCl-elevated seawater at 21 degrees C. At 24 degrees C, H. momus larvae develop competence to respond to KCl-seawater and initiate metamorphosis approximately 3 h after hatching. Larval trunks and tails separated from the anterior papillae region, but maintained in a common tunic at a distance of greater than 60 mu m, do not undergo metamorphosis when treated with KCl-seawater; normal muscle degradation does not occur in separated tails while ampullae develop from papillae-containing anterior fragments. Normal programmed degradation of myofibrils occurs when posterior fragments are fused to papillae-containing anterior fragments. These data indicate that H. momus settlement and metamorphosis only occurs when larvae have attained competence, and suggest that an anterior signalling centre is stimulated to release a factor that induces metamorphosis.