The Third International Conference on the Marine Biology of the South China Sea

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Protecting Hong Kong's marine biodiversity: present proposals, future challenges

Pollution from many sources, over-fishing and the rapid development of Hong Kong have had powerful, adverse, impacts upon local marine life reducing it to but a shadow of what it once was. This paper describes Hong Kong's newly enacted Marine Parks Ordinance Chapter 37 1995, discusses the existing situation with regard to the designation of marine parks and reserves, and describes the special features of each one. It argues that a territory-wide strategy will have to be implemented if representative intertidal and coastal water communities are to survive. Coastal zone planning and management need to be among the Hong Kong Government's highest priorities because there are indications that the marine parks and reserves will not be successful. The threats to them are too great. Conservation legislation and coastal planning exercises should also be integrated with those of China as soon as possible, especially for areas of coastline surrounding Hong Kong. This is because development within southern China is proceeding at such a pace that Hong Kong's protected areas are now being threatened by external factors as well as internal ones.published_or_final_versio

Escherichia coli DNA helicase I catalyzes a site- and strand-specific nicking reaction at the F plasmid oriT

A site- and strand-specific nick, introduced in the F plasmid origin of transfer, initiates conjugal DNA transfer during bacterial conjugation. Recently, molecular genetic studies have suggested that DNA helicase I, which is known to be encoded on the F plasmid, may be involved in this nicking reaction (Traxler, B. A., and Minkley, E. G., Jr. (1988) J. Mol. Biol. 204, 205-209). We have demonstrated this site- and strand-specific nicking event using purified helicase I in an in vitro reaction. The nicking reaction requires a superhelical DNA substrate containing the F plasmid origin of transfer, Mg2+ and helicase I. The reaction is protein concentration-dependent but, under the conditions used, only 50-70% of the input DNA substrate is converted to the nicked species. Genetic data (Everett, R., and Willetts, N. (1980) J. Mol. Biol. 136, 129-150) have also suggested the involvement of a second F-encoded protein, the TraY protein, in the oriT nicking reaction. Unexpectedly, the in vitro nicking reaction does not require the product of the F plasmid traY gene. The implications of this result are discussed. The phosphodiester bond interrupted by helicase I has been shown to correspond exactly to the site nicked in vivo suggesting that helicase I is the site- and strand-specific nicking enzyme that initiates conjugal DNA transfer. Thus, helicase I is a bifunctional protein which catalyzes site- and strand-strand specific nicking of the F plasmid in addition to the previously characterized duplex DNA unwinding (helicase) reaction

Spin-enhanced nanodiamond biosensing for ultrasensitive diagnostics

The quantum spin properties of nitrogen-vacancy defects in diamond enable diverse applications in quantum computing and communications. However, fluorescent nanodiamonds also have attractive properties for in vitro biosensing, including brightness, low cost and selective manipulation of their emission. Nanoparticle-based biosensors are essential for the early detection of disease, but they often lack the required sensitivity. Here we investigate fluorescent nanodiamonds as an ultrasensitive label for in vitro diagnostics, using a microwave field to modulate emission intensity and frequency-domain analysis to separate the signal from background autofluorescence, which typically limits sensitivity. Focusing on the widely used, low-cost lateral flow format as an exemplar, we achieve a detection limit of 8.2 × 10−19 molar for a biotin–avidin model, 105 times more sensitive than that obtained using gold nanoparticles. Single-copy detection of HIV-1 RNA can be achieved with the addition of a 10-minute isothermal amplification step, and is further demonstrated using a clinical plasma sample with an extraction step. This ultrasensitive quantum diagnostics platform is applicable to numerous diagnostic test formats and diseases, and has the potential to transform early diagnosis of disease for the benefit of patients and populations

Catharanthus roseus flower extract has wound-healing activity in Sprague Dawley rats

BACKGROUND: Catharanthus roseus L (C. roseus) has been used to treat a wide assortment of diseases including diabetes. The objective of our study was to evaluate the antimicrobial and wound healing activity of the flower extract of Catharanthus in rats. METHODS: Wound healing activity was determined in rats, after administration (100 mg kg(-1 )day(-1)) of the ethanol extract of C. roseus flower, using excision, incision and dead space wounds models. The animals were divided into two groups of 6 each in all the models. In the excision model, group 1 animals were topically treated with carboxymethyl cellulose as placebo control and group 2 received topical application of the ethanol extract of C. roseus at a dose of 100 mg/kg body weight/day. In an incision and dead space model group 1 animals were given normal saline and group 2 received the extract orally at a dose of 100 mg kg(-1 )day(-1). Healing was assessed by the rate of wound contraction, period of epithelization, tensile strength (skin breaking strength), granulation tissue weight, and hydoxyproline content. Antimicrobial activity of the flower extract against four microorganisms was also assessed RESULTS: The extract of C. roseus significantly increased the wound breaking strength in the incision wound model compared with controls (P < 0.001). The extract-treated wounds were found to epithelialize faster, and the rate of wound contraction was significantly increased in comparison to control wounds (P < 0.001), Wet and dry granulation tissue weights, and hydroxyproline content in a dead space wound model increased significantly (p < 0.05). Pseudomonas aeruginosa and Staphylococcus aureus demonstrated sensitivity to C. roseus CONCLUSION: Increased wound contraction and tensile strength, augmented hydroxyproline content along with antimicrobial activity support the use of C. roseus in the topical management of wound healing

Thick primary melanoma has a heterogeneous tumor biology: an institutional series

<p>Abstract</p> <p>Background</p> <p>Thick melanomas (TM) ≥4 mm have a high risk for nodal and distant metastases. Optimal surgical management, prognostic significance of sentinel node biopsy (SLNB), and benefits of interferon (IFN) for these patients are unclear. As a continuum of increasing tumor thickness is placed into a single TM group, differences in biologic and clinical behavior may be lost. The purpose of this study was to better characterize the diverse biology in TM, including the value of increasing thickness and nodal status information, potentially identifying high risk TM subgroups that may warrant more aggressive treatment/follow up.</p> <p>Methods</p> <p>155 consecutive TM patients treated at a single institution between 1971 and 2007 were retrospectively reviewed. Patient, disease and treatment features were analyzed with respect to disease-free (DFS) and overall survival (OS).</p> <p>Results</p> <p>Median patient age was 66 years and 68% of patients were men. The trunk was the most common TM location (35%), followed by the head and neck (29%) and lower extremities (20%). Median thickness was 6 mm and 61% were ulcerated. 6% patients had stage IV disease, 12% had clinical nodal metastases. Clinically negative lymph node basins were treated by observation (22 patients - 15.4%), elective lymph node dissection (ELND) (24 patients - 17.6%) or SLNB (91 patients - 67%). 75% of ELND's and 53% of SLNB's were positive. Completion node dissection was performed in 38 SLNB+ patients and 22% had additional positive nodes. 17% of the study patients received IFN. At median follow up of 26 months, 5 year DFS and OS were 42% and 43.6%. For SLNB positive vs negative, median DFS were 22 vs 111 months (p = 0.006) and median OS were 41 vs 111 months (p = 0.006). When stratified by tumor thickness ≤ vs > 6 mm, 5 year DFS was 58.3% vs 20% (p < 0.0001) and OS was 62% vs 20% (P < 0.0001). IFN had no impact on DFS or OS (p = 0.98 and 0.8 respectively).</p> <p>Conclusion</p> <p>Within the high risk group of patients with TM, cases with tumor thickness > 6 mm or a positive SLNB had a significantly worse DFS and OS (p < .0001, <.0001 and .006, .006).</p

Evaluation of wound healing activity of Allamanda cathartica. L. and Laurus nobilis. L. extracts on rats

BACKGROUND: Allamanda cathartica. L. is a perennial shrub used in traditional medicine for treating malaria and jaundice. Laurus nobilis. L. is a tree and has been used for its astringent, healing and diuretic properties. The objective of this study was to investigate the aqueous extracts of Allamanda and Laurus nobilis to evaluate their wound healing activity in rats. METHODS: Excision and incision wound models were used to evaluate the wound healing activity of both the extracts on Sprague Dawley rats. In each model, animals were divided into four groups of 10 animals each. In both the model, group 1 served as control and group 2 as reference standard. In an excision wound model, group 3 animals were treated with Allamanda (150 mg kg(-1 )day(-1)) and group 4 animals were treated with Laurus nobilis (200 mg kg(-1 )b.w day(-1)) for 14 days respectively. In the case of incision wound model, group 3 and 4 animals were treated with the extracts of Allamanda and Laurus respectively for 10 days. The effects of vehicles on the rate of wound healing were assessed by the rate of wound closure, period of epithelialisation, tensile strength, weights of the granulation tissue, hydroxyproline content and histopathology of the granulation tissue. RESULTS: The aqueous extract of Allamanda promoted wound healing activity significantly in both the wound models studied. High rate of wound contraction (P < .001), decrease in the period of epithelialisation (10.2 ± 0.13), high skin breaking strength (440.0 ± 4.53), significant increase in the weight of the granulation tissue (P < .001) and hydroxyproline (P < .001) content were observed in animals treated with the aqueous extract of Allamanda. Histological studies of the granulation tissue from the Allamanda treated group showed the presence of a lesser number of inflammatory cells, and increased collagen formation than the control. In Laurus nobilis treated animals, the rate of wound contraction, weight of the granulation tissue and hydroxyproline content were moderately high (P < .05). The histological study of the granulation tissue of the Laurus nobilis treated animals showed larger number of inflammatory cells, and lesser collagen when compared with the Allamanda treated group of animals. However, it was better than the control group of animals. CONCLUSION: The data of this study indicated that the leaf extract of Allamanda possesses better wound healing activity than the Laurus nobilis and it can be used to treat different types of wounds in human beings too

Risk assessment for the spread of Serratia marcescens within dental-unit waterline systems using Vermamoeba vermiformis

Vermamoeba vermiformis is associated with the biofilm ecology of dental-unit waterlines (DUWLs). This study investigated whether V. vermiformis is able to act as a vector for potentially pathogenic bacteria and so aid their dispersal within DUWL systems. Clinical dental water was initially examined for Legionella species by inoculating it onto Legionella selective-medium plates. The molecular identity/profile of the glassy colonies obtained indicated none of these isolates were Legionella species. During this work bacterial colonies were identified as a non-pigmented Serratia marcescens. As the water was from a clinical DUWL which had been treated with Alpron™ this prompted the question as to whether S. marcescens had developed resistance to the biocide. Exposure to Alpron™ indicated that this dental biocide was effective, under laboratory conditions, against S. marcescens at up to 1x108 colony forming units/millilitre (cfu/ml). V. vermiformis was cultured for eight weeks on cells of S. marcescens and Escherichia coli. Subsequent electron microscopy showed that V. vermiformis grew equally well on S. marcescens and E. coli (p = 0.0001). Failure to detect the presence of S. marcescens within the encysted amoebae suggests that V. vermiformis is unlikely to act as a vector supporting the growth of this newly isolated, nosocomial bacterium

The Plastid Genome of Eutreptiella Provides a Window into the Process of Secondary Endosymbiosis of Plastid in Euglenids

Euglenids are a group of protists that comprises species with diverse feeding modes. One distinct and diversified clade of euglenids is photoautotrophic, and its members bear green secondary plastids. In this paper we present the plastid genome of the euglenid Eutreptiella, which we assembled from 454 sequencing of Eutreptiella gDNA. Comparison of this genome and the only other available plastid genomes of photosynthetic euglenid, Euglena gracilis, revealed that they contain a virtually identical set of 57 protein coding genes, 24 genes fewer than the genome of Pyramimonas parkeae, the closest extant algal relative of the euglenid plastid. Searching within the transcriptomes of Euglena and Eutreptiella showed that 6 of the missing genes were transferred to the nucleus of the euglenid host while 18 have been probably lost completely. Euglena and Eutreptiella represent the deepest bifurcation in the photosynthetic clade, and therefore all these gene transfers and losses must have happened before the last common ancestor of all known photosynthetic euglenids. After the split of Euglena and Eutreptiella only one additional gene loss took place. The conservation of gene content in the two lineages of euglenids is in contrast to the variability of gene order and intron counts, which diversified dramatically. Our results show that the early secondary plastid of euglenids was much more susceptible to gene losses and endosymbiotic gene transfers than the established plastid, which is surprisingly resistant to changes in gene content