Mangrove expansion and population structure at a planted site,East London,South Africa

Avicennia marina (Forrsk.) Vierh. was planted in 1969 at Nahoon Estuary, East London, followed a few years later by the planting of Bruguiera gymnorrhiza (L.) Lam. and Rhizophora mucronata (L.) among the larger A. marina trees. This study tested the hypothesis that mangroves have expanded and replaced salt marsh over a 33-year period (1978–2011). It provides important information on mangroves growing at higher latitudes, where they were thought to not occur naturally due to lower annual average temperatures. It further provides insights on future scenarios of possible shifts in vegetation types due to climate change at one of the most southerly distribution sites worldwide. The expansion of mangroves was measured using past aerial photographs and Esri ArcGIS Desktop 10 software. In addition, field surveys were completed in 2011 to determine the population structure of the present mangrove forest and relate this to environmental conditions. The study showed that mangrove area cover increased linearly at a rate of 0.06 ha y^?1, while the salt marsh area cover also increased (0.09 ha y^?1) but was found to be variable over time. The mangrove area is still relatively small (<2 ha) and expanded mostly over a bare sandflat area. Avicennia marina was the dominant species and had high recruitment (seedling density was 33 822 ± 16 364 ha^?1). Only a few Bruguiera gymnorrhiza and Rhizophora mucronata individuals were found (<10 adult trees), although observations indicate that some young plants are becoming established away from the parent plants. The site provides opportunities for studies on mangrove/salt marsh interactions in response to a changing climate. Mangroves should not be planted in non-native areas as they may become invasive outside their natural range. However, future increases in temperature will certainly lead to a southerly expansion of mangoves in South African estuaries.     

Rhodococcus equi (Prescottella equi) vaccines; the future of vaccine development

For decades researchers have been targeting prevention of Rhodococcus equi (Rhodococcus hoagui/Prescottella equi) by vaccination and the horse breeding industry has supported the ongoing efforts by researchers to develop a safe and cost effective vaccine to prevent disease in foals. Traditional vaccines including live, killed and attenuated (physical and chemical) vaccines have proved to be ineffective and more modern molecular‐based vaccines including the DNA plasmid, genetically attenuated and subunit vaccines have provided inadequate protection of foals. Newer, bacterial vector vaccines have recently shown promise for R. equi in the mouse model. This article describes the findings of key research in R. equi vaccine development and looks at alternative methods that may potentially be utilised.     

Identification of management risk factors for VTEC O157 in young-stock in England and Wales

We conducted a cross-sectional study on 255 cattle farms in England and Wales to identify risk factors for verocytotoxin-producing E. coli O157 (VTEC). Exposure variables were collected at the levels of the farm and of the group of young-stock within the farms. On each farm a group of young-stock (6-18 months of age) was sampled to establish VTEC status. In our multiple logistic regression, farm VTEC status was associated with access to springs (OR: 0.31, CI95%: 0.12, 0.78) and assessing the wetness of the bedding material less frequently than daily (OR: 3.89 CI95%: 1.5, 10.2). At group-level we found no associated risk factors for animals housed outdoors in fields. Significant for groups housed in pens were wet bedding (wet OR: 3.43, CI95%: 1.3, 9.4; very wet OR: 4.24, CI95%: 1.2, 14.6), number of animals in the group (10-15 OR: 2.72, CI95%: 0.75, 9.9, 16-24, OR: 3.78, CI95%: 1.2, 12.3; >25 OR: 3.78, CI95%: 1.1, 12.7) and feeding straw (OR: 2.29, CI95%: 1.2, 5.5).     

Induction of Chitinase and β-1,3-Endoglucanase Proteins by UV Irradiation and Wounding in Grapefruit Peel Tissue

UV irradiation enhanced the resistance of grapefruit against the development of green mold décay caused byPenicillium digitatum, the main postharvest pathogen of citrus fruit, and significantly inhibited the fungus’ growth at the fruit wound sites. Immunoblotting analysis using specific citrus chitinase and β-1,3-endoglucanase antibodies, showed that UV irradiation, wounding of the fruit, or a combination of these two treatments, induced the accumulation of a 25 kD chitinase protein in the fruit’s peel tissue. On the other hand, UV irradiation or wounding of the fruit alone was unable to induce the accumulation of 39 and 43 kD β-1,3-endoglucanase proteins, but the combination of the two treatments increased these protein levels. It is suggested that both chitinase and β-1,3-endoglucanase may play a role in the UV-induced resistance of grapefruit againstP. digitatum. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 403/99. http://www.phytoparasitica.org posting June 3, 1999.     

Methods of detection of Chlamydia psittaci in domesticated and wild birds

OBJECTIVE: To study the occurrence of Chlamydia psittaci in domesticated and wild birds and compare the sensitivity of molecular detection with cell culture isolation. DESIGN: Study of cell culture isolation and PCR detection of C psittaci in avian samples. PROCEDURE: Samples were obtained from 485 birds. Domesticated birds were selected at random from pet shops, private aviaries and zoos, while wild birds were captured locally, sampled, and immediately released. Swabs were collected from choanal slit, conjunctiva and cloaca of each bird and pooled. Samples were divided into equal portions for use in PCR dot-blot and cell culture detection. PCR and dot-blot detection was based on the ompB gene. RESULTS: Prevalence of infection varied markedly between flocks of captive birds. It was highest where there were frequent changes in the flock members or where there were many birds confined in small areas. C psittaci was not detected in wild birds or water birds. The sensitivity of cell culture compared to PCR dot-blot detection was 68%. All samples positive by cell culture were also positive by PCR. CONCLUSIONS: PCR-dot blot detection of C psittaci in birds appears to be more sensitive than cell culture isolation in this study. C psittaci infection of birds may occur in clinically normal captive birds.     

Copper-Catalyzed Oxidation of Alcohols to Aldehydes and Ketones: An Efficient, Aerobic Alternative

An efficient, copper-based catalyst has been discovered that oxidizes a wide range of alcohols into aldehydes and ketones under mild conditions. This catalytic system utilizes oxygen or air as the ultimate, stoichiometric oxidant, producing water as the only by-product.     

Isotopic compositions of cometary matter returned by Stardust

Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme isotopic anomalies are rare, indicating that the comet is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen and neon isotope ratios suggest that indigenous organic matter and highly volatile materials were successfully collected. Except for a single (17)O-enriched circumstellar stardust grain, silicate and oxide minerals have oxygen isotopic compositions consistent with solar system origin. One refractory grain is (16)O-enriched, like refractory inclusions in meteorites, suggesting that Wild 2 contains material formed at high temperature in the inner solar system and transported to the Kuiper belt before comet accretion.     

Global honey bee viral landscape altered by a parasitic mite

Emerging diseases are among the greatest threats to honey bees. Unfortunately, where and when an emerging disease will appear are almost impossible to predict. The arrival of the parasitic Varroa mite into the Hawaiian honey bee population allowed us to investigate changes in the prevalence, load, and strain diversity of honey bee viruses. The mite increased the prevalence of a single viral species, deformed wing virus (DWV), from ~10 to 100% within honey bee populations, which was accompanied by a millionfold increase in viral titer and a massive reduction in DWV diversity, leading to the predominance of a single DWV strain. Therefore, the global spread of Varroa has selected DWV variants that have emerged to allow it to become one of the most widely distributed and contagious insect viruses on the planet.