Development of the False Root-knot Nematode,Nacobbus aberrans, on Sugarbeet

The duration of the embryogenic development of Nacobbus aberrans (= N. batatiformis) took 9-10 days at 25 C and 51 days at 15 C. The J₁ molted in the egg; hence the Je emerged from the egg. The effect of distilled water attd root leachates of kochia and sugarbeet was investigated at 5, 10, 15, 20, and 25 C. Root leachates did not significantly affect the percent of cumulative hatch of eggs, but temperature did significantly affect emergence of juveniles (p = 0.05). Less than 1, 5, and 20% of eggs hatched at 5, 10, and 15 C, respectively. The percent of cumulative hatch at 20 C was four times greater than at 15 C, while the highest percentage of juveniles emerged at 25 C. The duration of postembryogenic development from J₂ inoculation until the appearance of mature females with egg masses took 38 days, and the life cycle from egg to egg was completed in 48 days at 25 C. All immature stages, young females and males were migratory endoparasites. Young females were able to leave the root swellings, where they developed from juvenile stages, and re-enter the root, where they formed a true gall and became sedentary. Thirty days after inoculation with J₂ nematodes, specimens were detected in root tissues at 10, 15, 20, 25, and 30 C, hut not at 5 C. Five days after inoculation at 23 C ( ± 2 C), juveniles had penetrated the roots and caused slight swellings of the tip and axis of sugarbeet feeder roots. Large cavities extended from the cortical parenchyma to the periphery of the stelar area, and 50 % of the central cylinder was destroyed 25 days after inoculation at 23 C. No syncytia formation were detected in the sugarbeet root swellings infected with juveniles. Syncytia were associated only with adult females; hyperplasia, abnormal proliferation of lateral roots, and asymmetry of root structure were additional anatomical changes induced by adult females. Only very smooth annules but no cuticular ornamentations were noted by SEM on the perineal area of adult females.     

Effect of luteinizing hormone/choriogonadotropin receptor (LHCGR) gene on chicken reproductive traits

Luteinizing hormone/choriogonadotropin receptor (LHCGR) gene, potentially related to reproductive traits in chickens, was genotyped by using the Pooled DNA Sequencing, PCR–SSCP and Directing Sequencing techniques. 306 Erlang Mountain chickens form one line (SD03, a line that has been selected for egg quality from a local chicken breed in Sichuan province, China) were genotyped in this study. The associations between LHCGR polymorphisms and six reproductive traits [body weight at first egg (BWAFE), weight of first egg, age at first egg (AFE), number of eggs at 300 days of age (EN), body weight at 300 days of age and egg weight at 300 days of age (EWTA)] were estimated using the one-way analysis of variance method. Results showed that SNP +G4058A and SNP +T4099G of the LHCGR gene were significantly associated with BWFE and AFE. Birds with the AG genotype for the +G4058A SNP exhibited shorter AFE (P < 0.05) and greater EN than those of the GG and AA genotypes, suggesting a balancing selection (overdominance); the effect of allele C in SNP +C3021T and allele C in SNP +T4490C on EN and AFE is additive and may reflect the influence of positive selection. These alleles have promise as genetic markers for future marker-assisted selection.     

Development of Four Populations of Meloidogyne hapla on Two Cultivars,of Cucumber at Different Temperatures

The infectivity and development of four populations of Meloidogyne hapla were compared, at three temperatures, on tomato and two varieties of cucumber. A population from Canada produced few root-galls on cucumber and, except at 24 C, no larvae developed into adult females and produced egg masses. In contrast, a population with 45 chromosomes from America produced many galls on cucumber and small proportions of larvae became females and produced egg masses at 20 and 24 C. At 18 C this population produced no egg masses on cucumber, but a population from Britain and one from America with 17 chromosomes produced more egg masses at this temperature than at 20 or 24 C. Dissection of the galls showed that on cucumber many larvae died or their growth and development was slowed.     

The rate of preimaginal development of the blowfly, Calliphora vicina R.-D. (Diptera, Calliphoridae) under field and laboratory conditions

Open field experiments with the blowfly, Calliphora vicina originating from the environs of St. Petersburg showed that the correlation between the rate of its preimaginal development under the natural conditions and the mean daily temperature could be very closely approximated by linear regression. The sum of effective temperatures required for development from the egg to the puparium constituted ca 140 degree-days and from the egg to the adult, ca 320 degree-days with the lower thresholds of 5.8 and 4.8°C, respectively. The minimum duration of development (6–8 days from the egg to the puparium and 16–20 days from the egg to the adult) was recorded during the period of the highest mean temperatures (22–23°C) from July 8 to August 15 of 2010 and 2011. The rate of development under natural thermorhythms was not siggnificantly different from that under the laboratory conditions at constant temperatures from 12 to 23°C.     

Effect of egg storage duration and brooding temperatures on chick growth,intestine morphology and nutrient transporters

The effects of egg storage duration (ESD) and brooding temperature (BT) on BW, intestine development and nutrient transporters of broiler chicks were investigated. A total of 396 chicks obtained from eggs stored at 18°C for 3 days (ESD3-18°C) or at 14°C for 14 days (ESD14-14°C) before incubation were exposed to three BTs. Temperatures were initially set at 32°C, 34°C and 30°C for control (BT-Cont), high (BT-High) and low (BT-Low) BTs, respectively. Brooding temperatures were decreased by 2°C each at days 2, 7, 14 and 21. Body weight was measured at the day of hatch, 2, 7, 14, 21, 28 and 42. Cloacal temperatures of broilers were recorded from 1 to 14 days. Intestinal morphology and gene expression levels of H⁺-dependent peptide transporter (PepT1) and Na-dependent glucose (SGLT1) were evaluated on the day of hatch and 14. Cloacal temperatures of chicks were affected by BTs from days 1 to 8, being the lowest for BT-Low chicks. BT-High resulted in the heaviest BWs at 7 days, especially for ESD14-14°C chicks. This result was consistent with longer villus and larger villus area of ESD14-14°C chicks at BT-High conditions. From 14 days to slaughter age, BT had no effect on broiler weight. ESD3-18°C chicks were heavier than ESD14-14°C chicks up to 28 days. The PepT1 and SGLT1 expression levels were significantly higher in ESD3-18°C chicks than ESD14-14°C on the day of hatch. There was significant egg storage by BT interaction for PepT1 and SGLT1 transporters at day 14. ESD14-14°C chicks had significantly higher expression of PepT1 and SGLT1 at BT-Low than those at BT-Cont. ESD14-14°C chicks upregulated PepT1 gene expression 1.15 and 1.57-fold at BT-High and BT-Low, respectively, compared with BT-Cont, whereas PepT1 expression was downregulated 0.67 and 0.62-fold in ESD3-18°C chicks at BT-High and BT-Low. These results indicated that pre-incubation egg storage conditions and BTs affected intestine morphology and PepT1 and SGLT1 nutrient transporters expression in broiler chicks.     

Development ofDiatraea Saccharalis [Lep.: Pyralidae] at constant temperatures

At constant temperatures between 15.6 and 32°C the incubation time of eggs ofDiatraea saccharalis (F.) was reduced by each increase in temperature. At 34°C the time decreased. Highest (98.6%) and lowest (9.9%) egg hatch occurred at 26 and 34°C, respectively. Larvae completed development at temperatures ranging from 22 to 34°C; however, only 4.4% of the larvae pupated at 34°C. Duration of the larval stage at 30°C (♂=18.1 days; ♀=19.1 days) was ca. 14 days shorter than at 22°C. Maximum rate of development in the pupal stage occurred at 28°C (ca. 6.8 days), and a higher temperature increased developmental time and mortality. Adult longevity and egg production generally were reduced with increasing temperatures and egg production was highest at 24°C (729.8 eggs/ moth). As many as 7 larval stages occurred; but most larvae completed development in 5 stages, and none completed development in less than 5 stages. The female larval stage was ca. 1 day longer than that of males, and this difference occurred primarily in the 5th stage.     

Biological Relationship of Rotyleinchulus borealis on Several Plant Cultivars

The embryogenic development of Rolylenchulus borealis, at 24-26 C, was completed on corn, in 12-15 days, and the life-cycle of the nematode from egg to egg required 35-40 days at 20-25 C. Juveniles remained in the soil as preinfective stages for 17-19 days before becoming adults. Only immature vermiform and swollen egg-laying females were found attached to corn roots. Eggs were laid in a gelatinous matrix on the root surface; the number of eggs per egg mass was 45 ± 28 on corn roots. Bean, green pea, potato, sorghum, and sweet potato were also found to be hosts of R. borealis. The nematode established a permanent feeding site on corn root in an endodermal cell that became hypertrophied. Pericyclic cells close to the feeding site showed granular cytoplasm and nuclei with hypertrophied nucleoli. A cell wall ingrowth was also noted around the area of stylet penetration into the endodermal cell.     

Effect of pH and Chelating Agents on the Heat Resistance and Viability of Salmonella typhimurium Tm-1 and Salmonella senftenberg 775W in Egg White

Supplementation of egg white at pH 8.9 with 5 mg of disodium ethylenediaminetetraacetic acid (EDTA) per ml resulted in a kill of Salmonella typhimurium Tm-1 of greater than 10⁶ per ml after 28 days at 2 C. While at 28 C, supplementation with 7 mg of EDTA per ml resulted in approximately a 10⁶ kill in less than 24 hr. Kena supplementation at 40 mg/ml of egg white resulted in a kill of S. typhimurium Tm-1 of greater than 10⁶ after approximately 60 hr of storage at 28 C. This is in contrast to no reduction in viable count in unsupplemented egg white stored at 2 C and a 100-fold increase in viable count in that stored at 28 C. Supplementation of egg white with EDTA at 7 mg/ml or with Kena at 10 mg/ml also affected the heat resistant characteristics of the two organisms at 52.5 C, reducing the time required to kill 90% of the population (D value) at any pH by a factor of 2 to 6. There was a synergistic effect between EDTA and lactic acid when lactic acid was used to adjust EDTA-supplemented egg white to an acidic pH (5.3) which greatly decreased the heat resistance of Salmonella senftenberg 775W (from 100D to D).     

The Biology of Rotylenchulus macrodoratus

Rotylenchulus macrodoratus completed its embryogenic development in about 16-19 days at 18-32 C. On olive seedlings the life-cycle from egg to egg was completed in 45-55 days. The first molt occurred in the egg while the other three were superimposed, with retention of successive larval cuticles. Only immature vermiform and swollen egg-laying females were found attached to olive roots. Eggs are laid in a gelatinous matrix on the root surface. The maximum number of eggs seen was 55. Males were not parasitic. Dianthus barbatus, Parietaria officinalis, and Eriobotrya japonica were found to be hosts of the parasite. Observed in all infested hosts was an uninucleate giant cell that expanded from the endodermis toward the center of the stele in primary roots, and from the secondary vascular tissue toward the periphery of the cortex in secondary roots.     

Effects of Temperature and Root Leachates on Embryogenic Development and Hatching of Meloidogyne chitwoodi and M. hapla

At 20 C the duration of the embryogenic development of Meloiclogyne chitwoodi and M. hapla was about 20 days. At 10 C the embryogenic development was 82-84 days for M. chitwoodi and 95-97 days for M. hapla. The effect of distilled water and root leachates of potato cv. Russet Burbank, tomato cv. Columbian, and wheat cv. Hyslop on the hatching of eggs of the two root-knot nematode species was investigated at 4, 7, 10, 15, 20, and 25 C (± 1 C). Cumulative egg taatch was no greater in root leachates titan in distilled water, but temperature did significantly affect egg hatch (P = 0.05). Less than 1% of the eggs of both nematode species hatched at 4 C. The percent cumulative hatch at 10 C was significantly less (P = 0.05) than at higher temperatures for both nematodes and significantly more (P = 0.05) M. chitwoodi eggs hatched than did M. hapla eggs. At 15 G the percent cumulative hatch of both species was significantly lower (P = 0.05) than that at 20 and 25 C. The percent cumulative egg hatch of two species did not differ at 25 C, but was higher (P = 0.05) at 25 C than at 20 C. At 7 C the emergence of M. chitwoodi juveniles was about seven times (P = 0.01) greater than that of M. hapla in distilled water.     

Temperature Effects on Race Determination in Heterodera glycines

Currently there are 16 possible races for Heterodera glycines, and these are differentiated based on ability of a nematode population to develop on a set of four differential soybean genotypes. Because results are based on numbers of nematode females that develop to a specific stage rather than on the reproductive capability of these females, race determinations based on female indices may not represent results obtained after several reproductive cycles of H. glycines. Counting numbers of eggs and juveniles, and then developing corresponding indices, would allow reproduction to be considered in making race determinations. Our objectives were to compare the present race identification scheme for H. glycines based on female indices with those using egg and juvenile indices and to examine the effect of temperature on race designations using female, egg, and juvenile indices. Race designations for H. glycines populations from two locations in Illinois were determined at 20, 27, and 30 °C in a water bath. The numbers of females, eggs, and juveniles (at 19 days) were recorded, and an index based on each life stage was calculated. Race determinations based on female, egg, or juvenile indices were inconsistent when conducted at 20 °C, which demonstrates that this temperature is not suitable for identifying races of H. glycines. However race designations at 27 and 30 °C were consistent for all three indices. This indicates that counting females, eggs, or juveniles should be equally reliable when race determinations are conducted at these two temperatures, and choice of method would depend on investigator preference or research objective.     

Effects of temperature, salinity, and air exposure on development of the estuarine pulmonate gastropod Amphibola crenata

The primitive pulmonate snail Amphibola crenata embeds embryos within a smooth mud collar on exposed estuarine mudflats in New Zealand. Development through hatching of free-swimming veliger larvae was monitored at 15 salinity and temperature combinations covering the range of 2-30 ppt salinity and 15-25 °C. The effect of exposure to air on developmental rate was also assessed. There were approximately 18,000 embryos in each egg collar. The total number of veligers released from standard-sized egg collar fragments varied with both temperature and salinity: embryonic survival was generally higher at 15 and 20 °C than at 25 °C; moreover, survival was generally highest at intermediate salinities, and greatly reduced at 2 ppt salinity regardless of temperature. Even at 2 ppt salinity, however, about one-third of embryos were able to develop successfully to hatching. Embryonic tolerance to low salinity was apparently a property of the embryos themselves, or of the surrounding egg capsules; there was no indication that the egg collars protected embryos from exposure to environmental stress. Mean hatching times ranged between 7 and 22 days, with reduced developmental rates both at lower temperature and lower salinity. At each salinity tested, developmental rate to hatching was similar at 20 and 25 °C. At 15 °C, time to hatching was approximately double that recorded at the two higher exposure temperatures. Exposing the egg collars to air for 6-9 h each day at 20 °C (20 ppt salinity) accelerated hatching by about 24 h, suggesting that developmental rate in this species is limited by the rates at which oxygen or wastes can diffuse into and from intact collars, respectively. Similarly, veligers from egg capsules that were artificially separated from egg collars at 20 °C developed faster than those within intact egg collars. The remarkable ability of embryos of A. crenata to hatch over such a wide range of temperatures and salinities, and to tolerate a considerable degree of exposure to air, explains the successful colonization of this species far up into New Zealand estuaries.     

Temperature Effects on Development and Reproduction of Heterodera cajani on Pigeonpea

Effects of constant and fluctuating temperature on development and reproduction of Heterodera cajani were studied on pigeonpea cv. ICPL 87 in growth chambers at 10, 15, 20, 25, and 30 C and in a greenhouse fluctuating between 22.2 and 37.8 C. Nematode penetration was greatest (P = 0.001) in roots at 25 C; there was no penetration at 10 C. The basal threshold temperature for development was calculated to be 11 C. Completion of one H. cajani generation required 17, 28, 35, and 66 days (323, 392, 315, and 264 degree-days) at 30, 25, 20, and 15 C, respectively, and 19 days (356 degree-days) at a fluctuating temperature. Survival was greater at 20 and 25 C than at 15 and 30 C. The greatest (P = 0.05) number of females (17.9 females per root) were produced at 25 C, compared with 13.2 at 20 C, 7.9 at 30 C, and 2.5 females at 15 C. Nematode reproduction was 1.6 to 7.1 times greater at 25 C than at other temperatures. Emergence of juveniles from egg sacs and cysts was greater at 25 and 30 C than at 15 and 20 C. Equations were developed to predict nematode development rate, cumulative juvenile emergence from egg sacs and cysts, and population increases as influenced by temperature.     

n-3 Fatty acid content in eggs laid by hens fed with marine algae and sardine oil and stored at different times and temperatures

Inclusion of sardine oil (SO) in diets for laying hens significantly increases the n-3 polyunsaturated fatty acids (PUFAs) in the egg, but these are more sensitive to oxidation, so the storage time and temperature can cause a decrease in their concentration. Therefore, the objective of this study was to determine the effect of algae Macrocystis pyrifera, Enteromorpha spp., and Sargassum sinicola on n-3 PUFA contents in eggs from laying hens fed diets supplemented with sardine oil and stored for different times (0, 15, and 30 days) and temperatures (20°C and 4°C), for 8 weeks. One hundred and twenty hens were divided into four treatments: T1 (commercial diet), T2 (2% SO?+?10% M. pyrifera), T3 (2% SO?+?10% Enteromorpha), and T4 (2% SO?+?10% S. sinicola). At the end, 50 eggs per treatment were collected to quantify total lipids and egg n-3 PUFAs at different times (0, 15, and 30 days) and temperatures (20°C and 4°C) of storage. The results were analyzed using a 3?×?3?×?2 factorial design, and Tukey test to compare means (P?<?0.05). The results show that M. pyrifera and S. sinicola had a better effect on eicosapentaenoic acid, while Enteromorpha was better for docosahexaenoic acid. In relation to time and temperature, the content of the fractions analyzed in the three treatments at 15 days/4°C had a lower loss compared with eggs analyzed at day 0/20°C.     

Zur fortpflanzungsbiologie von mesostoma ehrenbergii (Focke, 1836) (Turbellaria)

1. At temperature levels from 10 to 25°C animals from resting eggs produce subitaneous eggs independent on temperature. In contrast animals from subitaneous eggs produce subitaneous eggs dependent on temperature. At a high rate subitaneous eggs are only formed at temperature levels above 20°C.
2. Below 10°C no development occurs in the juveniles. At temperatures of 30/22°C (24.7°C) the first subitaneous eggs are formed after 6–9 days, at 14/9°C (10.7°C) they are formed after 34 days. At different temperature levels the developmental rate of the young is from 10.5 to 42 days. One generation extends over 16.5 (30/22°C) to 75 days (14/9°C). The average egg production is 10–20 subitaneous eggs or 30–60 resting eggs. The maximum egg production of one individual is 50 subitaneous eggs or 84 resting eggs. 50% of the animals have just formed resting eggs, before the juveniles are hatched. Resting eggs in the first egg-batch are formed 6–20 days later than subitaneous eggs. The duration of life is between 65 (30/22°C) and 140 days (19/13°C).
3. Young worms in resting eggs have a dormance period of at least 15–30 days.

At room temperatures (20°C) no juvenile in resting eggs hatches from water. By combining room and refrigerator (3.5°C) temperatures the hatching rate increases to a maximum of 85%. To reach a hatching rate of 50–65% the influence of low temperatures must be at least 30 days. At room temperatures 60% of the young in resting eggs hatch from mud covered with water. Combining high and low temperatures the hatching success is between 67 and 81%, where the highest percentage of the young may hatch at room temperature. Up to 90 days low temperatures cause a maximum hatching rate of 79%. It decreases to approximately 30% after 180 days. At high temperatures resting eggs preserved in 100% moist mud, survive for two months. By adding a period of low temperatures the hatching rate increases to a maximum of 52%. Low temperatures are survived for more than 6 months. Up to 30 days preservation at 3.5°C causes a maximum hatching rate of 61%, up to 12o days it decreases to 30%. At room temperature the young in resting eggs are not resistant against air-dried mud (30–40% rel. air moisture). Combining high and low temperatures air-dried mud is endured 1 month (hatching rate 5–14%). Preservation of 30–120 days at 3.5°C and 70% rel. air moisture result in a hatching rate of 43–61%. li]4. In the open air in Middle-Europe there occur 5–6 generations of M. ehrenbergii per life-cycle. The first generation hatches from resting eggs in May, where the production of subitaneous eggs is independent on temperature. All other generations up to October hatch from subitaneous eggs. The egg-production of those worms is dependent on environmental factors. In summer subitaneous egg production prevails, in autumn resting egg production. The abundance during the life-cycle is dependent on the number of animals which produce subitaneous eggs. Resting eggs are predestinated to endure periods of dryness and cold. The life-cycles of the species M. lingua and M. productum are different from those of M. ehrenbergii in length and in the number of generations. In both species 7 generations occur over 8 to 8.5 respectively 5.5 months. M. nigrirostrum only forms resting eggs. The life-cycle consists of one generation from February/March to May/June.     

The prediction of development rate and the effect of temperature for the meiobenthic copepod,Microarthridion littorale (Poppe)

Specimens of the meiobenthic copepod, Microarthridion littorale (Poppe ), were cultured in the laboratory on substrata consisting of sediment, benthic diatoms, and detrital filtrate. No significant differences were found in egg development times of M. littorale cultured in winter vs. summer, and we suggest several possible interpretations. Egg development time was independent of the number of clutches a female carried in the laboratory, suggesting confidence in estimates of egg development time without knowledge of the number of broods a female has produced. Egg, naupliar, and copepodite development rates were determined over a range of temperatures. Regression analyses indicated that both Bělehrádek's temperature function and a curvilinear model adequately described the relationship between development and temperature for all three developmental stages. A linear model was also adequate to describe copepodite development (Lack of Fit Test, P = 0.05). Eight of the reared females produced egg sacs, allowing us to estimate generation time (egg to egg) as 29.6 days at 25°C and 21.6 days at 33°C. Generation times were compared to those for a closely related benthic copepod, Tachidius discipes. Life history parameters between the two differed, and we advise caution when using predictions of development time derived from a species other than the one being studied.     

Oögenesis defects in the ecd-1 mutant of Drosophila melanogaster, deficient in ecdysteroid at high temperature

Oögenesis defects observed in ecd-1 females depend on the stage at which the shift from the permissive temperature (20°C) to the non-permissive temperature (28.5°C) is performed. Pupae shifting earlier than 48 hours after puparium formation have underdeveloped ovaries and die at emergence. In ecd-1 females shifted 2 days or more after puparium formation, egg chambers develop normally up to the early vitellogenic stage, and then degenerate—no mature oöcytes are formed. When the shift is performed after maturation of the females at 20°C, their egg-laying rate decreases slowly after the shift; the eggs display abnormal chorions and fail to develop into larvae. By shifting the ecd-1 females back to 20°C, a complete reversal of abnormalities of eggshell formation and egg development may be observed. The temperature-sensitive periods related to these different defects were determined. For egg development, the period extends from 2 days to 1 day before laying. For eggshell formation, the beginning and end of the temperature-sensitive period were not separated—both were located around 24 hours before laying. For the block of vitellogenesis, we concluded that this is probably due to an inhibition of yolk uptake. This inhibition would be effective only in follicles younger than the previtellogenic stage 7 when submitted to the non-permissive temperature.     

Synchronisation of egg hatching of brown hairstreak (Thecla betulae) and budburst of blackthorn (Prunus spinosa) in a warmer future

Synchronisation of the phenology of insect herbivores and their larval food plant is essential for the herbivores’ fitness. The monophagous brown hairstreak (Thecla betulae) lays its eggs during summer, hibernates as an egg, and hatches in April or May in the Netherlands. Its main larval food plant blackthorn (Prunus spinosa) flowers in early spring, just before the leaves appear. As soon as the Blackthorn opens its buds, and this varies with spring temperatures, food becomes available for the brown hairstreak. However, the suitability of the leaves as food for the young caterpillars is expected to decrease rapidly. Therefore, the timing of egg hatch is an important factor for larval growth. This study evaluates food availability for brown hairstreak at different temperatures. Egg hatch and budburst were monitored from 2004 to 2008 at different sites in the Netherlands. Results showed ample food availability at all monitored temperatures and sites but the degree of synchrony varied strongly with spring temperatures. To further study the effect of temperature on synchronisation, an experiment using normal temperatures of a reference year (T) and temperatures of T + 5°C was carried out in climate chambers. At T + 5°C, both budburst and egg hatch took place about 20 days earlier and thus, on average, elevated temperature did not affect synchrony. However, the total period of budburst was 11 days longer, whereas the period of egg hatching was 3 days shorter. The implications for larval growth by the brown hairstreak under a warmer climate are considered.