Study on morphology,pathogenicity and genetic diversity of Wilsonomyces carpophilus isolates,the causal agent of shot hole of stone fruit trees based on RAPD-PCR in Iran

Shot hole disease is one of the most important diseases of stone fruit trees in Iran. The disease is wide spread among orchards of Prunus spp. During spring and summer of 2007, 80 monoconidial isolates of the pathogen were recovered from infected leaves, fruits and twigs of different Prunus spp. in West Azerbaijan, Tehran, Ghazvin and Razavi Khorasan provinces of Iran and were studied taxonomically. Based on morphological and physiological characteristics and growth optimal temperature, all isolates were identified as Wilsonomyces carpophilus. Seedlings of stone fruits (apricot, almond, peach, nectarine, plum, sweet cherry and sour cherry) were used for pathogenicity tests. All seedlings were susceptible to the fungal isolates and showed disease symptoms on twigs, leaves, buds and petioles. Genetic diversity of 28 selected fungal isolates was investigated based on DNA fingerprinting by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), using four random primers. Based on cluster analysis of the PCR results from the four primers, 10 fingerprinting groups (clonal lineages) and 27 haplotypes were identified. Clonal lineages “C”, “D” and “E”, each with six haplotypes formed the biggest clonal lineages, but other clonal lineages (“B”, “F”, “G”, “H”, “I” and “J”) included only one isolate. No correlation was detected among clonal lineages with the location of selected isolates and their host species. A correlation was found between the substrate (fruit, twig or leaf) and clonal lineages, particularly in “C” clonal lineage. The results showed that the fungus population had high genetic diversity which is distributed among the different areas of Iran.     

Novel surface specialization on a sea anemone egg: “Spires” of actin-filled microvilli

The ultrastructure of the “spiny” surface of Tealia crassicornis eggs is examined in detail by scanning and transmission electron microscopy in order to understand its function. Long microvilli are clustered together in spiral aggregates of 50–75 microvilli called “spires.” There are about 15,000 spires per egg. Dense bundles of microfilaments making up the cores of these microvilli are shown to be composed of actin by staining with the fluorescent dye nitrobenzoxadiazole (NBD)-phallacidin. It is postulated that the bundles of actin and the spires of microvilli are stiff and provide reinforcement to the egg surface. Such postulated properties would provide physical protection for these large eggs which, unlike the eggs of most invertebrates, appear to lack all extracellular investing coats.     

SHORT-TERM IMPACTS OF FORMULATIONS OF BACILLUS THURINGIENSIS VAR. ISRAELENSIS DE BARJAC AND THE ORGANOPHOSPHATE TEMEPHOS,USED IN BLACKFLY (DIPTERA: SIMULIIDAE) CONTROL,ON RHEOPHILIC BENTHIC MACROINVERTEBRATES IN THE MIDDLE ORANGE RIVER,SOUTH AFRICA

Summary

The impacts of larvicides used in the control of blackflies (Diptera: Simuliidae) on macroinvertebrates in the stones-in-current biotope were assessed during 8 field trials in the middle Orange River, South Africa. Two Bacillus thuringiensis var. israelensis (B.t.i.) products (Vectobac^R 12AS and Teknar^R HP-D) and the organophosphate temephos (Abate^R 200EC) were applied at recommended and high dosages to simulate “operational” and “worst-possible” scenario's respectively. Mortality was evaluated either by direct counting of invertebrates on stones before and after application, or by ranking invertebrates on a 4-point relative abundance scale before and after application. In addition, the re-appearance of benthic invertebrate population densities after temephos application was examined.

At the recommended dosage (1.2 ppm/10 min), B.t.i. significantly reduced blackfly larval numbers (P<0.001) and those of the chironomid Rheotanytarsus fuscus Freeman (P<0.05). At high dosage (20 ppm/10 min), numbers of the filter-feeding mayfly Tricorythus discolor (Burmeister) (P<0.01) and the chironomid Cardiocladius sp. (P<0.05) were also significantly reduced. No Simulium predators were directly affected by B.t.i., but there were indications of food shortage amongst Hydropsychidae and Hirudinea.

Temephos caused significant reductions in the relative abundance of 5 taxa at 0.05 ppm, 3 to 6 taxa at 0.1 ppm, and 9 taxa at 1.0 ppm (P<0.05). “Non-target” organisms which were most affected included the chironomid R. fuscus, the mayflies Baetis glaucus Agnew and Choroterpes elegans Barnard, and the caddisflies Cheumatopsyche thomasseti Ulmer and Amphipsyche scottae Kimmins. The mayfly T. discolor was tolerant of temephos, even at high dosage (1.0 ppm/10 min). In winter, most taxa re-appeared within 19 days, and population densities were back to pre-treatment levels within 35 days.

It is concluded that good reduction of blackfly populations may be obtained with minimal direct impact on the “non-target” fauna, provided recommended dosages of temephos are not exceeded. Overdosing with temephos may result in high mortality of “non-target” organisms, including blackfly predators, and should be avoided.     

The abundance of phytophilous invertebrates on different species of submerged macrophytes*

SUMMARY. 1. We tested Krecker's model (1939) which states that the abundance of invertebrates per unit macrophyte biomass varies with plant species and is higher on plants with finely dissected leaves than on plants with broad leaves. The abundance of invertebrates was measured in thirteen lacustrine macrophyte beds in southern Québec, Canada. The model was tested for the total abundance of invertebrates and for the abundances of Chironomidae, Cladocera, Cyclopoida, Gastropoda, Hydracarina, Ostracoda and Trichoptera. 2. More epiphytic invertebrates were found on the dissected Myriophyllum spp. than on the broad-leaved Potamogeton amplifolius Tuckerm, P. robbinsii Oakes and Vallisneria americana Michx. (P<0.01). More invertebrates were also found on P. amplifolius than on P. robbinsii or V. americana (P<0.01). The total abundance of invertebrates was not systematically related to the degree of plant dissection. 3. The abundances of Chironomidae, Cladocera, Cyclopoida, Gastropoda, Hydracarina, Ostracoda and Trichoptera varied on different plant species (P<0.01). Contrary to Krecker's hypothesis, however, macrophytes with finely dissected leaves (Ceratophyllum demersum and Myriophyllum spp.) did not in general support more invertebrates per unit plant biomass than plants with large leaves (Potamogeton amplifolius, P. robbinsii and Vallisneria americana).     

ARCHAEOPTERIS MACILENTA,ANATOMY AND MORPHOLOGY OF ITS FROND

The stem, rachides, and pinnae of Archaeopteris macilenta, formerly considered to be a fern of Devonian age, comprise a branch system in which the ultimate divisions heretofore referred to as pinnules are the leaves. The primary vascular system of the “frond” is a lobed siphonostele from which leaf traces arise in a spiral sequence. The anatomy of the “rachis” and of the “pinnae” is shown to be similar to that of the stem, Callixylon, which bore these “fronds.” Branching, epidermal pattern and stomates are described for the spirally arranged leaves (fertile pinnules). Attachment and dehiscence of sporangia as well as their stomates are reported. Archaeopteris is retained in the Class Progymnospermopsida which includes plants with gymnospermous anatomy and pteridophytic reproduction. It is suggested that Actinopodium, Svalbardia and Siderella are related closely to Archaeopteris and that this group of genera shows evolutionary stages in webbing of leaves and planation of branch systems. The opportunities for ontogenetic studies of the arborescent genus Archaeopteris are pointed out.     

The structure of the littoral: effects of waterlily density and perch predation on sediment and plant‐associated macroinvertebrate communities

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“Reverse” sexual dichromatism in a Neotropical frog

Sexual dichromatism is widespread among animals, but examples of “reverse” sexual dichromatism, in which females are more brightly colored than males, are extremely rare. We discovered a unique case of reverse sexual dichromatism in the golden rocket frog (Anomaloglossus beebei), a diurnal Neotropical frog. Females are bright “golden” in color, and males are drab tan with brown pigmentation that darkens when they are calling. Here, we document this color variation with calibrated digital photography and further show that there is no evidence for sex‐specific habitat matching; both sexes live in the same well‐lit habitat on green bromeliad leaves. Our results suggest that color variation in this species is an intraspecific signal and provide an important exception to the general expectation that males are more visually conspicuous in species with conventional sex roles.     

External diversity is restrained by internal conservatism: New nudibranch mollusc contributes to the cryptic species problem

Cryptic species are an important concept of modern biodiversity studies and a potential basis for immensely increasing the amount of biological diversity worldwide; however, the conceptual grounds of cryptic species still need to be refined. Here, using a remarkable example from marine invertebrates, the case of a species complex of common large‐sized nudibranchs of the genus Dendronotus in European waters is presented, which is relevant for the ongoing cryptic species discussion. Based on extensive sampling in the seas of Northern Hemisphere from United Kingdom to the Sea of Japan, a morphological and molecular framework is constructed for understanding the diversity of European Dendronotus nudibranchs. The present study discovered notable multilevel character diversity within the common Dendronotus “frondosus” species complex. This implies the highest degree of variation of external characters with parallel colour patterns among different species and significantly constrained conservatism of internal characters. The molecular data are congruent with the stable differences in the internal features and confirm the presence of three distinct species in this complex. While two species were already known, the third species is evidently new, based on morphological and molecular evidence and is described here as Dendronotus europaeus sp. n. In the light of multilevel character diversity, the general problem of plausibility of the distinction and practical usage of the terms “cryptic” and “pseudocryptic” species is discussed.     

Scanning Electron Microscopy of Pseudomonas syringae pv, morsprunorum on Sweet Cherry Leaves

Scanning electron microscopy indicated that sub-stomatal cavities on sweet cherry leaves are “protected sites” which shelter resident populations of Pseudomonas syringae pv. morsprunorum. Bacteria entered the stomata, multiplied in the cavities and emerged in a mass 6 days after inoculation. There were no visible symptoms, suggesting that the pathogen colonized the host in “sub-clinical” numbers to generate populations which were then released onto the leaf surface under suitable conditions.     

A chronological assessment of foraging activities of the Cotton Pigmy Goose,Nettapus coromandelianus Gmelin, 1789 at Dulahara pond,Ratanpur, Chhattisgarh,India

This study was planned to assess the foraging activity of ecological important avian species the N. coromandelianus at Dulahara pond of Ratanpur, Chhattisgarh. In present work we observed the effect of “time of the day” and “photoperiod” on daytime foraging activities of N. coromandelianus. The most applied foraging skills of N. coromandelianus were documented for two repetitive days each for the period of long days (March and April 2015) and short days (December 2015 and January 2016). One-way ANOVA (by SPSS 16.0) was employed to observe the effects of “photoperiod” and “time of the day” on daytime foraging pattern in order to the frequency of foraging techniques. The rhythms in daytime foraging movement were estimated by means of Cosinor rhythmometry at 24 h and 12 h. The current study clarified that the N. coromandelianus mostly applied three main techniques viz., head and neck dipping, diving and striking on which both the diving and striking were the most employed technique while the head and neck dipping was less employed technique during foraging. Moreover, the N. coromandelianus maximally involved for foraging activities during the short day than long day.     

PHYLOGENETIC AFFINITIES OF “CHANTRANSIA” STAGES IN MEMBERS OF THE BATRACHOSPERMALES AND THOREALES (RHODOPHYTA)1

This study evaluated the phylogenetic relationship among samples of “Chantransia” stage of the Batrachospermales and Thoreales from several regions of the world based on sequences of two genes—the plastid‐encoded RUBISCO LSU gene (rbcL) and the nuclear SSU ribosomal DNA gene (SSU rDNA). All sequences of “Chantransia macrospora” were shown to belong to Batrachospermum macrosporum based on both molecular markers, confirming evidence from previous studies. In contrast, nine species are now associated with “Chantransia pygmaea,” including seven species of the Batrachospermales and two of the Thoreales. Therefore, the presence of “C. macrospora” in a stream can be considered reliable evidence that it belongs to B. macrosporum, whereas the occurrence of “C. pygmaea” does not allow the recognition of any particular species, since it is associated with at least nine species. Affinities of “Chantransia” stages to particular taxa were congruent for 70.5% of the samples comparing the rbcL and SSU analyses, which were associated with the same or closely related species for both markers. Sequence divergences have been reported in the “Chantransia” stage in comparison to the respective gametophyte, and this matter deserves further attention.     

Respirationsintensität in Stäinmen, Zweigen und Blältern von Laubbäumen im tropischen Regenwald und in temperierten Wäldern

Respiratory Activity in Stem, Branches and Leaves of Evergreen Trees in Tropical Rain Forest and of Deciduous Trees in Temperate Climate.— Reduced to the same temperature, the respiratory activity of different parts of tropical rain forest trees and of corresponding parts of temperate deciduous trees is approximately the same. In particular, the leaf-blades of Danish deciduous trees and of tropical rain forest trees from the lowland of Côte d'Ivoire (57° north. lat.) have nearly the same respiratory activity at 20°C: the blades of the extreme shade leaves about 0.1 mg CO₂, those of the extreme sun leaves about 0.8 mg CO₂ per 50 cm² (one side only) per hour at 20°C. This is in accordance with the fact that the blades of shade leaves, respectively Sim leaves, of the tropical rain forest trees are built in the same way as the blades of deciduous trees in our temperate climate. The respiratory activity shows that they have the same “concentration” of living cells, the same “concentration” of active plasma. The respiratory activity of trunk and branches depends mainly on three factors: diameter of the stem-section or branch-section, nutritional condition, and temperature. The respiratory activity of trunk and branches of hardwoods in temperate climate is also dependent on the season. The estimations on stems and branches from the temperature trees were made In July–August. There was in most cases a remarkable agreement in respiratory activity between temperate and tropical hardwoods: Branches with a diameter of about 0.5–2 cm have a respiration of about 70–100 mg CO₂ per kg fresh weight per hour at 20°C. Trunk sections with a diameter over 20 cm have a respiratory activity of about 3–5 mg CO₂, per kg fresh weight per hour at 20°C. In the older parts of a stem most of the cells are dead. The agreement in respiratory activity probably means that the “concentration” of living cells in the older parts of the stem of tropical and temperate hardwoods is the same.     

Comparisons of the Colonisation by Invertebrates of Three Species of Wood,Alder Leaves,and Plastic “Leaves” in a Temperate Stream

Small woody debris in streams is abundant, and may be a food source or may provide a substrate on which other food sources such as biofilm may develop, both of which may be significant to invertebrates in times of food scarcity. We examined patterns of invertebrate colonisation of small woody debris (veneers of red alder, Douglas‐fir, and western red cedar), red alder leaves, and plastic (as an inert substrate to mimic leaves). Invertebrate colonisation was high on alder leaves, but low on wood substrates and plastic, controlling for the available surface area. Detritivorous invertebrates had significantly higher colonisation rates of alder leaves versus the other four substrates, whereas predators and collectors did not (consistent with their use of these as substrates and not food). All wood decreased in mass by <15% and leaves by ∼50% over the 75 days of the experiment. For all taxa tested, there was no significant difference in their colonisation of the wood veneers versus the plastic sheets. These results suggest that wood was not directly used by these invertebrates as a food source, or that there could be similar biofilm development on the surfaces of these substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Biophysical Examinations of the Bending Stability of Various Stele Types and the Upright Axes of Early “Vascular” Land Plants

Biophysical methods allow quantitative deductions as to the “bending effectivity” of various stele types and the contribution of different tissues to the stability of upright plant axes. Considering the first occurrence of the different stele types in geological history, a strong tendency towards a higher “bending effectivity” can be observed. It can be shown that Rhynia gwynne-vaughanii, Aglaophyton major (Rhynia major) and Asteroxylon mackiei as well as probably the vast majority of early “vascular” land plants were turgor systems, i.e. that the parenchyma (when fully turgescent) is by far the most important contributory factor towards the bending stability of the upright axes.     

ILPR repeats adopt diverse G‐quadruplex conformations that determine insulin binding

The insulin‐linked polymorphic region (ILPR) is a VNTR region located upstream of the insulin (INS) gene consisting of the repeat 5′‐ACAGGGGTGTGGGG (repeat a) and several less abundant sequence repeats (b–n). Here, we have investigated the structural polymorphism of G‐quadruplexes formed from the most common repeat sequences (a–c) and their effect on insulin protein binding. We first established that the ILPR repeats “b” and “c” can form quadruplex structures. Insulin has previously been shown to bind a G‐quadruplex formed by a dimer of the repeat “a”. Our findings show that insulin binds preferentially to the repeat “a” G‐quadruplex (K_d = 0.17 ± 0.03 μM) over G‐quadruplexes formed from other ILPR repeats that were tested (K_ds from 0.71 ± 0.15 to 1.07 ± 0.09 μM). Additionally, the Watson‐Crick complementary relationship between the loop regions of repeat “a” (ACA and TGT) seemingly play an important role in favoring a specific G‐quadruplex conformation, which based on our data is critical for insulin binding. Affinity for insulin is reduced in sequences lacking the putative WC complementarity, however upon engineered restoration of complementarity, insulin binding is recovered. A DMS footprinting assay on the repeat “a” G‐quadruplex in the presence of insulin, combined with binding affinities for ILPR mutants led to identification of a loop nucleotide critical for binding. Uniquely, insulin shows clear preference for binding to the G‐quadruplexes with the more antiparallel feature. Collectively, our results illustrate the specific nature of insulin binding to the ILPR G‐quadruplexes and begin to provide molecular details on such interactions. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 21–31, 2010. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Evaluation of an aphid‐rearing method using excised leaves and agar medium

The present study evaluated the effectiveness of an aphid‐rearing method devised by Milner in 1981 using Acyrthosiphon pisum and its host plant Vicia faba. In the “agar‐leaf method,” excised leaves of V. faba were attached to the surface of 1% agar gel containing nutrient solution, and test aphids were transferred onto the leaves. Excised leaves grew in size and weight on the agar medium. Fecundity, longevity, body size and developmental time to adulthood were compared between aphids reared using the agar‐leaf method vs. those reared on V. faba seedlings under the same conditions. No significant difference was detected between the two treatments for any of the four parameters, suggesting that the aphids grew and reproduced on excised leaves as successfully as on V. faba seedlings. This method was also useful for inducing males and oviparous females at lower temperature and in short days. Therefore, the present study confirms the effectiveness of using excised leaves on agar and suggests that this method could be applied to the rearing of other aphids, phytophagous mites, leaf miners and leaf‐gall formers.     

A Study of Diaphanosoma Species (Crustacea: Cladocera) of the “Mongolianum” Group

Material from 49 localities in Europe, Asia and Africa is used to study two similar Diaphanosoma species, viz. D. mongolianum UENO, 1938, and D. lacustris KORINEK, 1981, both of which were described earlier under other names, the most common of which were “D. brachyurum”, “D. leuchtenbergianum” and “D. birgei lacustris”. These species are redescribed in detail, consideration being given to interpopulational and individual morphological variability, the type material, and material from type localities. The morphology of the setae of the swimming antennae is studied in detail, and the author concludes that some of them are not only used for swimming but also perform a sensory function. Some aspects of the biology of the species are described. They inhabit water bodies of different types, are often so abundant that they constitute the main component of zooplankton communities, and are an important link in the trophic chain. Little known cases of the co-occurrence of Diaphanosoma species in a water body are described. Localities known for D. mongolianum and D. lacustris are situated mainly in the temperate and subtropical zones, the former species penetrating farther north than the latter. However, they are also found in the White Nile (Sudan) and Ethiopian lakes. This southward penetration may be connected with the azonal distribution of fluviatile fauna and with the altitude of Ethiopian lakes.