温度对抗性朱砂叶螨发育和繁殖的影响

比较了朱砂叶螨Tetranychus cinnabarinus (Boiduval)敏感品系（S）、阿维菌素抗性品系（AR）和甲氰菊酯抗性品系（FR）在不同温度下的发育和繁殖情况,用王-兰-丁模型拟合了各品系发育速率与温度的关系。结果表明,在36℃下,S品系和FR品系卵均不能孵化,而AR品系却能完成世代发育。15℃下,AR和FR品系的世代历期分别比S品系延长8.0和6.2天,产卵前期均比S品系缩短约2.0天。在20～28℃下,S品系繁殖力大于抗性品系; 在34℃下, AR品系的产卵量显著大于S和FR品系。S、FR和AR品系发育临界高温分别为36.0℃、36.1℃和42.4℃。结果提示AR品系对高温的适应能力较S和FR品系明显增强。     

Reproductive allometry does not explain the temperature-size rule in water striders (Aquarius remigis)

Most ectotherms follow the temperature-size rule meaning that individuals growing up under cool conditions are larger as adults than those growing up in warm conditions. This pattern is difficult to explain because growth is usually slower in the cold meaning it takes longer to reach a larger adult size. One potential explanation for this pattern is that the typical increase in fecundity with body size is steeper in cool environments than it is in warm environments. As such, the relative gain in fecundity for being larger in the cold would compensate for the extra time it takes to grow to that size. We present the first empirical test of this model using the water strider Aquarius remigis. Individuals were reared at either 20° or 25°C with subsampling at each instar to estimate growth trajectories. At adult eclosion, half were switched to the alternate temperature and all females isolated, mated, and reproductive output measured for 3 weeks. We found that A. remigis does follow the temperature-size rule but that fecundity was highly plastic with respect to laying temperature such that the slightly greater fecundity of those reared at 20°C was due to their larger size. Overall, those laying at 25°C were more fecund and showed a positive relationship between body size and fecundity. Those laying at 20°C did not show a significant relationship between size and fecundity. As such, the reproductive allometry shows a pattern reverse to what would be needed for a larger size in the cold to be adaptive in this species. Although A. remigis follows the temperature-size rule over this temperature range, this is likely due to a constraint on growth and development rather than being adaptive plasticity.     

Reproductive Consequences of Clonal Growth in Stenocereus eruca, a Rare Clonal Cactus of the Sonoran Desert

Stenocereus eruca is a prostrated, self-incompatible cactus endemic to the Sonoran Desert that regenerates primarily through clonal propagation. Clonal growth is expected to affect mate availability by influencing the number and spatial distribution of mating types. In this paper we examine the role of clonal growth on female fecundity through a series of pollination experiments in a population of S. eruca. We set up a pollen supplementation experiment using five distance treatments with pollen collected at 1, 10, 100, 1000 and 25000 m from receptor flowers during the years 2001 and 2002 and evaluated genetic sifmilarities between pairs of receptor-donor ramets through RAPD markers. Our data on fruit set, number of seeds/fruit, germination and overall fecundity revealed that S. eruca show a significant reduction in female fecundity when pollination occurs between ramets located at short distances (1 and 10 m), while genetic data showed high levels of similarity at those distances. The reduction in female fecundity is apparently a consequence of geitonogamy and inbreeding depression. Our data suggest that clonal growth and geitonogamy are likely to be partially responsible for the low levels of sexual reproduction and seedling recruitment observed in populations of S. eruca. Co-ordinating editor: H. Kudoh     

Why get big in the cold? Size–fecundity relationships explain the temperature‐size rule in a pulmonate snail (Physa)

Most ectotherms follow a pattern of size plasticity known as the temperature‐size rule where individuals reared in cold environments are larger at maturation than those reared in warm environments. This pattern seems maladaptive because growth is slower in the cold so it takes longer to reach a large size. However, it may be adaptive if reaching a large size has a greater benefit in a cold than in a warm environment such as when size‐dependent mortality or size‐dependent fecundity depends on temperature. I present a theoretical model showing how a correlation between temperature and the size–fecundity relationship affects optimal size at maturation. I parameterize the model using data from a freshwater pulmonate snail from the genus Physa. Nine families were reared from hatching in one of three temperature regimes (daytime temperature of 22, 25 or 28 °C, night‐time temperature of 22 °C, under a 12L : 12D light cycle). Eight of the nine families followed the temperature‐size rule indicating genetic variation for this plasticity. As predicted, the size–fecundity relationship depended upon temperature; fecundity increases steeply with size in the coldest treatment, less steeply in the intermediate treatment, and shows no relationship with size in the warmest treatment. Thus, following the temperature‐size rule is adaptive for this species. Although rarely measured under multiple conditions, size–fecundity relationships seem to be sensitive to a number of environmental conditions in addition to temperature including local productivity, competition and predation. If this form of plasticity is as widespread as it appears to be, this model shows that such plasticity has the potential to greatly modify current life‐history theory.     

Erythromycin resistant mutations in Bacillus subtilis cause temperature sensitive sporulation.

Summary All of several hundred erythromycin resistant (ery^R) single site mutants ofBacillus subtilis W168 are temperature sensitive for sporulation (spo^ts). The mutants and wild type cells grow vegetatively at essentially the same rates at both permissive (30° C) and nonpermissive (47° C) temperatures. In addition, cellular protein synthesis, cell mass increases and cell viabilities are similar in mutant and wild type strains for several hours after the end of vegetative growth (47° C). In the mutants examined, the temperature sensitive periods begin when the sporulation process is approximately 40% completed, and end when the process is 90% complete. At nonpermissive temperatures, the mutants produce serine and metal proteases at 50% of the wild type rate, accumulate serine esterase at 16% of the wild type rate, and do not demonstrate a sporulation related increase in alkaline phosphatase activity.The ery^R and spo^ts phenotypes cotransform 100%, and cotransduce 100% using phage PBS1. Revertants selected for ability to sporulate normally at 47° C (spo⁺), simultaneously regain parental sensitivity to erythromycin. No second site revertants are found.Ribosomes from ery^R spo^ts strains bind erythromycin at less than 1% of the wild type rate. A single 50S protein (L17) from mutant ribosomes shows an altered electrophoretic mobility. Ribosomes from spo⁺ revertants bind erythromycin like parental ribosomes and their proteins are electrophoretically identical to wild type. These data indicate that the L17 protein of the 50S ribosomal subunit fromBacillus subtilis may participate specifically in the sporulation process.     

Prospective analysis of the invasive potential of the European grapevine moth Lobesia botrana (Den. & Schiff.) in California

• 1 The polyphagous European grapevine moth Lobesia botrana (Den. & Schiff.) is the principal native pest of grape berries in the Palearctic region. It was found in Napa County, California, in 2009, and it has subsequently been recorded in an additional nine counties, despite an ongoing eradication programme. The present study aimed to assess prospectively its potential geographical distribution and relative abundance in California and the continental U.S.A. A subsidiary goal was to provide explanation for timing control measures.
• 2 Data from the European literature were used to formulate and parameterize a holistic physiologically‐based demographic model for L. botrana. This model was linked to an extant mechanistic model of grapevine phenology, growth and development that provides the bottom‐up effects of fruiting phenology, age and abundance on L. botrana dynamics. Fruit age affects larval developmental rates, and has carryover effects on pupal development and adult fecundity. Also included in the model were the effects of temperature on developmental, survival and fecundity rates.
• 3 Observed daily weather data were used to simulate the potential distribution of the moth in California, and the continental U.S.A. The relative total number of pupae per vine per year was used as the metric of favourability at all locations. The simulation data were mapped using grass gis ( http://grass.osgeo.org/ ).
• 4 The model predicts L. botrana can spread statewide with the highest populations expected in the hotter regions of southern California and the lower half of the Central Valley. In the U.S.A., areas of highest favourability include south Texas, and much of the southeast U.S.A.
• 5 The effects of a warmer climate on pest abundance were explored by increasing observed mean temperatures 2° and 3 °C. L. botrana abundance is expected to increase in northern California and in the agriculturally rich Central Valley but to decrease in the hot deserts of southern California where summer temperatures would approach its upper thermal limit.
• 6 Analysis of the timing of mating disruption pheromone for control of L. botrana suggests the greatest benefit would accrue by targeting adults emerging from winter diapause pupae and the flight of first summer adults.

     

Anaerobic Induction of Adherence to Laminin in Lactobacillus gasseri Strains by Contact with Solid Surface

The effect of growth conditions on adhesion was studied in six species belonging to Lactobacillus acidophilus homology groups. Namely, 17 strains including 6 fresh isolates of L. gasseri from human feces were assessed for their adherence to immobilized fibronectin, laminin, and type IV collagen. These extracellular matrix proteins were used as a model of damaged intestinal mucosa. When the bacteria were grown on MRS agar under anaerobic conditions, all eight L. gasseri strains and one L. johnsonii strain showed strong adhesiveness to laminin, but not when grown in static MRS broth. A similar pattern was observed in four L. gasseri strains in terms of adherence to fibronectin. No L. gasseri or L. johnsonii strains exhibited adhesion to type IV collagen under either growth condition. Adhesion of L. acidophilus, L. crispatus, L. amylovorus, and L. gallinarum was not affected by the growth conditions. Although protease treatment of L. gasseri cells abolished the adhesion, periodate oxidation of the cells increased it except in one strain. The adherence of L. gasseri cells was diminished by periodate and α-mannosidase treatments of immobilized laminin. The above results suggest that mannose-specific proteinaceous adhesion can be induced in L. gasseri by contact with a mucosal surface in the anaerobic intestinal lumen.     

Pulsed-field gel electrophoretic analysis and some characteristics of Staphylococcus aureus isolated from retail foods and human hands

This study investigates whether there is a predominant Staphylococcus aureus strain in retail foods and healthy human hands, and examines the relationship between pulsed-field gel electrophoresis (PFGE) banding patterns and the S. aureus characteristics of staphylococcal enterotoxin (SE) type, coagulase type, and β-lactamase activity. Ninety-four strains of S. aureus isolated from retail foods and healthy human hands were analyzed by PFGE. Several strains isolated from the same shop or a chain store showed identical patterns, indicating that the origins of these strains were identical. After excluding these strains showing identical patterns, 54 strains were used for the PFGE analysis. No spread of a particular clone in the environment surrounding the food was apparent. The PFGE analysis of these 54 strains was classified in 6 lineages (L1-L6). There was no relationship between the PFGE banding pattern and coagulase type or SE type. Eleven (84.6%) of the 13 isolates in PFGE banding pattern L5 did not produce β-lactamase, suggesting that the production of β-lactamase influenced a specific PFGE banding pattern.     

Effect of temperature on the sex ratio and life table parameters of the leek-(L1) and tobacco-associated (T) Thrips tabaci lineages (Thysanoptera: Thripidae)

Temperature strongly affects insect biological response. Effects of temperature on the sex ratio, preoviposition, fecundity, egg hatchability rate, and adult longevity of the L1 and T Thrips tabaci lineages were studied under laboratory conditions at three constant temperature levels (15, 23, and 30°C) on cabbage and tobacco leaf discs, respectively. Results showed that temperature affects all the tested life table parameters of L1 and T lineages. The proportion of female's log-linearly increased as temperature increased. Preoviposition period, fecundity, adult longevity, and egg hatchability rate were reduced significantly with increasing temperature. In both lineages, the lowest egg hatchability rates were recorded at 30°C and the highest rates were recorded at 15°C. Mean fecundity of the L1 and T lineages were 107.63 and 84.83 at 23°C, respectively, and mean fecundity of the L1 and T lineages were 19.88 and 70.82 at 15°C, respectively. The lowest mean fecundity was recorded at 15°C and 30°C for the L1 and T lineages, respectively. Mean longevity were 34.22 and 81.82 days at 15°C for L1 and T lineages, respectively. Whereas, the shortest mean longevity (13.63 and 13.91 days) was observed at 30°C for the L1 and T lineages, respectively. Our results demonstrated that 23°C was the optimum temperature for fecundity among the studied temperature levels for the studied population of the L1 and T T. tabaci lineages.     

30S subunit mutations relieving restriction of ribosomal misreading caused by L6 mutations

Summary Mutants were analyzed biochemically and genetically in which restriction of translational misreading by ribosomes containing an altered L6 protein is relieved. Amongst 100 such strains eight possessed an altered S4 and two a mutant S5 protein. The protein-chemical type of L6 mutation seems to influence the kind of S4 mutant form selected. Also, only a few types of S4 ram mutations are obtained and they are different from those usually found amongst suppressors of streptomycin-dependent (Sm^D) strains. The S4 mutations selected are able to reduce the level of streptomycin-resistance of strA1 or strA40 strains and they confer extreme hypersensitivity to aminoglycosides when present alone. On the other hand, S4 mutations from Sm^D suppressor strains only weakly reverse L6 restriction. The results imply that control of translational fidelity is an intersubunit function and that protein L6 (an interface protein) cooperates with 30S proteins by directly or indirectly determining parameters involved in aminoacyl-tRNA recognition.     

Production of thaxtomin a by two species ofStreptomyces causing potato scab

A total of nine isolates of streptomycetes were isolated from scab lesions on potato tubers. Five of nine isolates were pathogenic on potato minitubers. Four of the pathogenic isolates produced thaxtomin A (ThxA) in infected tuber tissues. The lesion surface areas inducing ThxA were highest in treatment of the minitubers with an extract of OMB inoculated with S-66 and S-67, intermediate with that inoculated with S-64 and lowest with S-63. The pathogenic isolates were identified by gray aerial mycelia, melanin pigment productivity, the type of spore chain morphology and carbon utilization asS. scabies strains S-63, S-64 and S-68, andS. acidiscabies strains S-66 and S-67. Strains S-63 and S-64 produced 0.65 and 1.60 mg ThxA per L of OMB, respectively, strains S-66 and S-67 producing similar amounts,viz. 2.36 and 2.10 mg/L, respectively. The optimal temperature for production (by both species) was 28 °C. Production of ThxA byS. scabies strain S-64 andS. acidiscabies strain S-66 was suppressed at least 50-fold at 0.5 and 0.3 % of glucose, respectively. Fructose enhanced the production by both species.     

Life history and morphological plasticity of the soybean aphid,Aphis glycines

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a pest of soybean, Glycine max (L.) Merr. (Fabaceae), from eastern Asia that was first reported in North America in 2000. The influence of temperature on plasticity of life history and morphological traits of the soybean aphid has not been tested despite observable differences in population growth and morphology among isolates in laboratory colonies. Therefore, we used three isolates of the aphid to test whether lifespan, growth rate, fecundity, and morphology were plastic at 16, 24, and 28 °C. Population size of the aphid was influenced by temperature, probably because two reproductive traits, maximum number of offspring in 1 day and total fecundity, were plastic and increased in successive generations at 24 °C. All morphological traits were plastic, including lengths of body parts, number of antennal segments and caudal hairs, and color of siphunculi and body, and they were differentially influenced by isolate and temperature. Knowledge about the life history and morphology of the soybean aphid may help identify its capacity for phenotypic plasticity in heterogeneous temperatures and identify how temperature influences its survival, population growth, and diversity.     

Life history traits of Aphis gossypii Glover (Hom., Aphididae) reared on four widely distributed weeds

Variation in the life history traits of cotton aphids, Aphis gossypii Glover, reared on four widely distributed weeds, Ageratum houstonianum Mill., Bidens pilosa L. var. radiata Sch. Bip., Solanum nigrum L. and Spermacoce latifolia Aubl., were investigated. Cotton aphids were reared in the laboratory at 25°C. Each host plant had a distinct effect on aphid life history traits. Cotton aphids reared on S. nigrum had a significantly shorter developmental period, and age-specific fecundity peaked early. In contrast, cotton aphids reared on S. latifolia had a long developmental period and low age-specific fecundity. Cotton aphids that fed on B. pilosa and A. houstonianum displayed intermediate rates of growth and age-specific fecundity. Because the curves of age-specific fecundity ( m_x ) and age-specific net maternity ( l_x  m _x ) on each host plant were close together, development time and the pattern of age-specific fecundity were the major factors determining the population growth potential of the cotton aphid on each weed. As a result, the intrinsic rate of population growth for aphids reared on S. nigrum was significantly higher ( r_m =0.527 ± 0.011) than it was for aphids reared on S. latifolia ( r_m =0.194 ± 0.012).     

Fragmentation heterogeneity of 23S ribosomal RNA in Haemophilus species

The fragmentation of 23S rRNA of 22 Haemophilus influenzae strains and eight strains belonging to other Haemophilus species was investigated. Instead of intact molecules, the 23S rRNA molecules were found to be cleaved into two to five smaller conserved fragments in most strains examined, especially in H. influenzae type b (5/6) and nontypeable strains (5/5). One or two conserved potential cleavage sites were identified by PCR analysis of the strains showing a fragmented 23S rRNA pattern. The relevant nucleotide sequences were determined and compared to H. influenzae Rd, which contains intact 23S rRNA molecules. An identical 112 bp long intervening sequence (IVS) at position 542 and a conserved 121–123 bp IVS sequence at position 1171 were found in two H. influenzae type b strains and one nontypeable strain. Among the strains with fragmented 23S rRNA, nearly half showed a heterogeneous cleavage pattern due to the dispersion of IVSs among different 23S rRNA operons. The localization of the conserved H. influenzae IVSs coincided well with the extensively studied IVSs among other bacteria, but differed in nucleotide sequence from any other reported IVSs. Therefore, the IVSs of Haemophilus 23S rRNA may originate from a common source that is independent of other bacteria.     

Growth of various ecotypes ofLemna paucicostata in Japan under various temperature conditions,and their wintering forms

Lemna paucicostata in Japan is classified into 4 types, N-1, N-2, K and S types. S type strains which are distributed in southern Japan grew more rapidly than other strains at the temperatures of both 27 and 17C. With the extension of the culture period at 17 C to which the plants had been transferred from 25C, the growth rate increased greatly in S type strains, while it decreased in N-1 type strains which are distributed widely from Hokkaido to Kyushu, and particularly in those distributed in the northern area. S type strains survived winter mostly in the form of normal fronds under natural conditions at Kyoto (minimum temperature is lower than OC), while most of the fronds of N-1 type strains died after producing seed before winter. Thus S type strains are considered to have adapted to the climate of southern Japan so as to survive winter in the form of fronds, while N-1 type strains overwinter in the form of seed. N-2 type strains which are distributed in the northern part of the area adjacent to the Japan Sea produced turion-like fronds during winter under natural conditions, while none of the other strains did. The K type strain which was found only at the campus of Kyoto University overwintered only in the form of fronds which produce no seed.     

Some cultural characteristics of mycelia of a mycorrhizal fungus,Lyophyllum shimeji

Cultural characteristics of 45 strains ofLyophyllum shimeji and 10 strains of three related species were determined. The average optimum temperature for mycelial growth ofL. shimeji on a medium consisting of rye grains was 24.9°C, slightly higher than those forL. fumosum andL. decastes. The average mycelial growth rate of theL. shimeji strains, each at its optimum temperature, was 2.0 mm/day, almost the same as that ofL. decastes and 2 times greater than those ofL. semitale andL. fumosum. All strains ofL. shimeji could grow on beech and pine sawdust, but none could significantly decompose beech wood blocks. Of the 45 strains ofL. shimeji, 3 strains had ability to form primordia on the rye grain medium without the host plant.This study was supported in part by the Forestry Agency, Japan.     

Ovarian dynamics and fecundity regulation in blueback herring,Alosa aestivalis,from the Connecticut River,US

We analyzed ovarian dynamics of anadromous blueback herring, Alosa aestivalis, in Connecticut River with the principal aim of exploring oocyte recruitment and how it shapes the fecundity pattern. We examined the oocyte release strategy and analyzed spawning cyclicity by linking oocyte growth to the degeneration of postovulatory follicles. Females were accordingly classified as pre-spawners, early and late active spawners, and oocyte recruitment intensity was compared among the different spawning phases. Oocyte recruitment occurred continuously and in parallel with spawning activity, a pattern which is diagnostic of indeterminate fecundity. However, both fecundity and oocyte recruitment intensity progressively decreased (tapered) throughout spawning, until the ovary was depleted of vitellogenic oocytes. There was no massive atresia of vitellogenic oocytes at the end of the spawning season, which is atypical of indeterminate spawners. We propose that tapering in oocyte recruitment and fecundity is an adaptation to the high energetic expenditure of the upstream spawning migration.     

The effect of growth temperature on esterase patterns in psychrotrophic Bacillus species and other Gram-positive genera

The growth temperature of Bacillus stearothermophilus was previously reported to affect the esterase band pattern obtained after gel electrophoresis. In this study gel electrophoresis of esterases was done on a group of Antarctic bacterial strains cultivated at different temperatures to investigate whether band shift due to a change in growth temperature was a general phenomenon or limited only to select groups. Most strains studied were in the Bacillus genus. Standard strains of known Bacillus species and other Gram-positive genera were examined for comparative purposes. A change in the esterase band pattern was observed as a result of variation in growth temperature. Two major esterase band were dominant in this diverse group of species.     

Cold-sensitive growth of a mutant of Escherichia coli with an altered ribosomal protein S8: analysis of revertants.

Summary 26 cold-resistant revertants of a cold-sensitiveEscherichia coli mutant with an altered ribosomal protein S8 were analyzed for their ribosomal protein pattern by two-dimensional polyacrylamide gel electrophoresis. It was found that 16 of them had acquired the apparent wild-type form of protein S8, one exhibits a more strongly altered S8 than the original mutant and two revertants regained the wild-type form of S8 and, in addition, possess alterations in protein L30. The ribosomes of the residual revertants showed no detectable difference from those of the parental S8 mutant.The mutation leading to the more strongly altered S8 was genetically not separable from the primary S8 mutation; this indicates that both mutations are very close to each other or at the same site. The structural gene for ribosomal protein L30 was mapped relative to two other ribosomal protein genes (for proteins S5 and S8) by the aid of one of the L30 mutants: The relative order obtained is:aroE....rpmD(L30)....rpsE(S5)....rpsH(S8)....THe L30 mutation impairs growth and ribosomal assembly at 20°C and is therefore the first example of a mutant with a defined 50S alteration that has (partial) cold-sensitive ribosome assembly. A double mutant was constructed which possesses both the S8 and the L30 mutations. It was found that the L30 mutation had a slight antagonistic effect on the growth inhibition caused by the S8 mutation. Thus the L30 mutants might have possibly arisen from the original S8 mutants first as S8/L30 double mutants which was followed by the loss of the original S8 lesion.     

Reproduction of the annual fish Austrolebias nigrofasciatus (Rivulidae) maintained at different temperatures

Temperature is considered an important factor that influences the life cycle of annual fishes, however the thermal preferendum of Austrolebias nigrofasciatus reproduction has not been defined. The hypothesis was that the fecundity of the species would respond differently within the temperature range analyzed, presenting an optimum thermal. Thus, this study investigated the effect of temperature on the fecundity of A. nigrofasciatus for the first time under laboratory conditions. Pairs of A. nigrofasciatus were placed in aquaria with temperatures of 17, 21 or 25°C, with four pairs (replicates) for each treatment, for five weeks. Contrary to expected, there were no significant differences in fecundity parameters among the tested temperatures, but the weekly fecundity at 17 and 21°C was more homogeneous than at 25°C. During the experimental period, the temperature did not affect male growth; however, at 25°C there was a negative effect on female body growth. The condition factor was also influenced, suggesting a tendency towards a negative energy balance with increasing temperature. The results indicate that temperatures between 17 and 21°C are suitable for broodstock maintenance.