Anther diversity and function inVerticordia DC. (Myrtaceae)

Anther form and structure across the taxonomic groups inVerticordia were examined. The three anther types which were recognised — rectangular, oblong and saccate, accord well with the three subgenera into which the genus has been divided. The sporogenous part of the anther has a fairly typical angiosperm anatomy. However in many species there is a small or large gland in the upper filament/connective which contains lipidic contents. The anatomy of this structure is based on that of the oil glands which are ubiquitous in Myrtaceae primary tissues. However the gland is usually much larger than these and is schizolysigenous in origin. Evolutionary development of the anthers in the genus is related to pollination systems and the development of secondary pollen presentation from the upper style in some groups. Anther glands may have originally had a protective function for the sporogenous tissue. However in different groups the function has changed or the gland has disappeared. In some species in subgenusChrysoma (which does not have secondary pollen presentation) the gland contents seem to be an additional food source for pollinators. In other groups, with the development of secondary pollen presentation the protective function has become redundant and anther glands have either disappeared or produce contents which have become part of the process of pollen dispersal.     

Practical applications of monitoring results to improve managing for coral reef resilience: a case study in the Mexican Caribbean

Marine protected areas (MPAs) are promoted as an effective strategy to balance human use and conservation of marine resources, yet case studies have shown mixed results regarding MPA success. Managing to promote resilience is widely recognized as a priority for MPAs that focus on the conservation of coral reefs and the ecological services they provide. To this end, there is an acute need to develop and implement methods that assimilate monitoring results into comprehensive summaries that can be understood and acted upon by local management to promote resilience. We used the Parque Nacional Arrecife de Puerto Morelos (PNAPM) as a model MPA to evaluate the utility of a resilience index framework proposed by Maynard et al. (Coral Reefs 29:381–391, 2010b) that uses a suite of broad- and local-scale indicators to rank the relative resilience of sites. Based on monitoring data we identify local stressors adversely impacting coral reef resilience that can be influenced by management actions. Improving regulation enforcement, conducting targeted invasive species removals, reallocating and restricting tourist activities, and establishing nutrient level regulations were identified as realistic adaptive management actions to promote resilience within the PNAPM. This first application of the Maynard et al. (Coral Reefs 29:381–391, 2010b) resilience index framework to a Caribbean MPA provides an example for MPA managers of the value of their monitoring data and the utility of a broadly applicable management tool to assist in managerial decisions. Moving beyond simply monitoring sites to management action is essential to promote resilience and maintain the health and existence of coral reef ecosystems.     

Choristoneura fumiferana entomopoxvirus prevents metamorphosis and modulates juvenile hormone and ecdysteroid titers

Larvae of the spruce budworm, Choristoneura fumiferana, infected with C. fumiferana entomopoxvirus (CfEPV) continue to feed and grow without undergoing metamorphosis and die as moribund larvae. The lethal dose (LD(50)) and lethal time (LT(50)) values for fourth instar larvae are 2.4 spheroids and 25.2 days, respectively. One hundred percent of the control fourth instar larvae, which were fed water instead of virus, pupated by 18 days post feeding (PF). Only 30% of the larvae that were fed the LD(50) dose and none of the larvae that were fed the LD(95) dose pupated by 18 days PF. Of the control larvae, 95% became adults by 24 days PF, whereas in the treated group only 2% of larvae that were fed the LD(50) dose and none of the larvae that were fed the LD(95) dose became adults by 24 days PF. Some of the virus-treated larvae died as either larval/pupal or pupal/adult intermediates. These phenotypic effects were similar to the larval/pupal and pupal/adult intermediates, resulting from treating larvae with juvenile hormone (JH) or its analogs, which suggests that EPV may cause such abnormalities by modulating JH and/or ecdysteroid titers. In untreated sixth instar larvae the JH titer decreased to low levels by 24 h after ecdysis and remained low throughout larval life. EPV-fed sixth instar larvae had 2112 pg/ml on day 0, 477 pg/ml on day 1 and 875 pg/ml on day 8 of the sixth instar. Control larvae contained 860 ng of ecdysteroids per ml hemolymph on day 8 of the sixth instar, whereas EPV-treated larvae of the same age (30 days PF) had only 107 ng of ecdysteroids per ml of hemolymph. Thus, EPV infection results in increased JH titer and decreased ecdysteroid titer. Northern hybridization analysis was performed using RNA isolated from control and EPV-fed larvae and cDNA probes for (i) juvenile hormone esterase (JHE), which is JH inducible, (ii) Choristoneura hormone receptor 3 (CHR3), which is ecdysteroid inducible, and (iii) larval specific diapause associated protein 1 (DAP1), whose expression is larval specific. EPV-treated larvae showed higher levels of JHE and DAP1 mRNA and lower levels of CHR3 mRNA, indicating that they had higher levels of JH and lower levels of ecdysteroids. Thus, our data show that EPV prevents metamorphosis by modulating ecdysteroid and JH levels.     

An ecdysone-inducible putative "DEAD box" RNA helicase in the spruce budworm (Choristoneura fumiferana)

RNA helicases are a family of enzymes that unwind nucleic acid duplexes, such as RNA/RNA and RNA/DNA, in a 3' to 5' direction into single-stranded polynucleotides. A putative RNA helicase cDNA (CfrHlc64) was isolated from the spruce budworm, Choristoneura fumiferana. CfrHlc64 was 1998 nucleotides in length, and the deduced protein had 565 amino acids with a predicted molecular mass of 64 kDa. It contained eight functional motifs conserved in the "DEAD box" family of RNA helicases. The deduced amino acid sequence showed 10-50% identities to homologues of other species from bacteria to human. In vitro expression of the cDNA resulted in recombinant proteins of 64 kDa as expected from the deduced amino acid sequence. Northern blotting and RT-PCR analyses revealed the presence of CfrHlc64 mRNA in all developmental stages from embryo to adult. Higher levels of CfrHlc64 mRNA were detected in the fat body and midgut than in the epidermis of sixth instar larvae. The CfrHlc64 protein was distributed mainly in the fat body. Female adults expressed CfrHlc64 mRNA at higher levels than male adults. The nonsteroidal ecdysone agonist, tebufenozide, enhanced the expression of CfrHlc64 in a dose-dependent manner.     

Vegetative and seedling regeneration after fire in planted Sardinian pinewood compared with that in other areas of Mediterranean-type climate

Aim Fire is a key disturbance in Mediterranean‐type climates. It has effects on plant community structure and composition and on the evolution of different groups of the flora. This study aimed to quantify changes in demography and vegetative regeneration caused by fire in key species in Mediterranean vegetation and to examine the hypothesis of convergence in characteristics of species in relation to fire by comparing the occurrence of bioecological groups of plants in the Mediterranean basin with groups of plants in other areas of Mediterranean‐type climate. Methods Changes in the demography and species composition after fire were studied in a plant community developed from a pinewood (Pinus halapensis Miller plantation) in north‐western Sardinia. The demography of the three main species dominating the community after fire, Cistus monspeliensis L., Pistacia lentiscus L. and Chamaerops humilis L., was quantified by quadrat measurements in areas of the plantation which had never been burnt and in different parts 1 and 8 years after fire. Vegetative regeneration of resprouting species was also quantified. From the results of the survey and examination of published material, comparison was made between bioecological groups of species in different regions with Mediterranean‐type climate to assess the similarities and differences in the biogeographic distribution of what can be broadly considered fire‐related functional groups of plants. Results Seeder and sprouter species showed contrasting population responses to fire in an area planted to pines over 50 years ago but subsequently in part subjected to fire. Mean species richness at a 25 m² scale decreased by c. 28% over 8 years after fire. C. monspeliensis in the unburnt pinewood was sparse and sporadic but recruitment after fire was prolific and produced plant densities similar to those of similar seeder species in other Mediterranean Basin areas and in Californian chaparral. However density was very variable between burnt areas of different ages. In particular, seedling recruitment was much lower under the canopies of P. lentiscus than away from the canopy. Sprouter species (P. lentiscus and C. humilis) had recruited into the pinewood over time since planting of the pines but did not recruit after fire. Above‐ground parts of plants were killed by fire and resprout stem density per plant increased initially but later decreased slightly due to self thinning of stems on each plant. Main conclusions Plant demographic and floristic changes after fire in the Sardinian pinewood were similar to those reported for other Mediterranean plant communities. Resprouting species only recovered by vegetative means and, in contrast to seeder species, underwent thinning of stems within, rather than between, plants, so plant density did not change after fire in resprouting species. The Tertiary relic, strongly resprouting, animal‐dispersed group of species in the Mediterranean Basin has a homologous group in the North American mediterraneoid flora but not in the Southern Hemisphere. In contrast, the general group of resprouting species which recruit after and/or between fires in the Southern Hemisphere mediterraneoid areas corresponds to only a small group of taxa in the Mediterranean basin. The bioecological group of seeder species, which are killed by and establish prolifically after fire, are represented in both Northern and Southern Hemisphere Mediterranean‐type heathlands but are much more species rich in the south.     

Osteoclast cell-surface changes during the egg-laying cycle in Japanese quail

The medullary bone serves as a source of labile calcium mobilized during calcification of the egg shell in birds. Quantitative histological methods demonstrate that the numbers of medullary bone osteoclasts and nuclei per osteoclast remain unchanged during the egg cycle in the Japanese quail (Coturnix). Therefore, cyclic changes in bone resorption cannot be explained by modulations of osteoclasts from and into other bone cells, a mechanism previously suggested for certain species of birds. Rather, dramatic changes in osteoclast cell-surface features occur during the egg cycle, which might account for cyclic variations in resorptive activity. During egg shell calcification, osteoclasts with ruffled borders are closely apposed to bone surfaces; the cytoplasm is rich in vacuoles that contain mineral crystals and seem to derive from the ruffled border. At the completion of egg shell calcification, the ruffled borders and vacuoles move away from the bone surface, although the osteoclast remains attached to the bone along the filamentous or "clear" zone. Associated with the disappearance of the ruffled borders is the appearance of extensive interdigitated cell processes along the peripheral surface of the osteoclast away from the bone. These unusual structures, which may serve as a reservoir of membrane, largely disappear when ruffled borders and associated structures reappear. Therefore, in these hens, the osteoclasts modulate their cell surface rather than their population during the egg cycle.