Occurrence of Staphylococcus aureus and evaluation of anti-staphylococcal activity of Lactococcus lactis subsp. lactis in ready-to-eat poultry meat

A total of 181 ready-to-eat poultry meat samples were examined for the presence of Staphylococcus aureus, and 11 (6 %) were found to have S. aureus contamination. Of 11 S. aureus isolates, 10 (91 %) were resistant to at least one antibiotic used in this study, and 2 were resistant to oxacillin. Lactococcus lactis subsp. lactis was tested as a bio-control agent. All the S. aureus isolates were found to be sensitive to antimicrobial products in L. lactis subsp. lactis supernatants; the zones of inhibition were in the range of 5.0 mm?±?0.70 mm to 19.8 mm?±?0.83 mm with the majority of isolates. As a competitive flora in mixed culture (LAPTg broth) and protective culture in poultry meat, L. lactis subsp. lactis was effective against S. aureus isolates; the growth of S. aureus isolates was almost negative after 32 h incubation in mixed culture. The population of S. aureus was reduced substantially to almost log 1 CFU/g after 25 days of incubation in protective culture. The pH of the test cultures also decreased sharply with time.     

Environmental factors influencing liana community diversity,structure and habitat associations in a tropical hill forest,Malaysia

Background: Although lianas are important in forest ecosystems, information on the environmental factors influencing their diversity, structure and habitat associations is scanty.

Aims: This study had the aim of determining variation in liana diversity, structure and habitat associations across different topographic habitats, and the environmental factors influencing them, in the Penang Hill Forest Reserve, Malaysia.

Methods: Liana diversity, structure and habitat associations were examined in 30 plots, 40 m × 40 m, randomly demarcated within three topographic habitats (flatland, slope and valley). The physico-chemical properties of the soils in the plots were determined and the altitude and slope of the plots recorded.

Results: Liana species richness, diversity and structure varied significantly among the topographic habitats. Liana species richness, diversity and abundance variations were related to soil moisture, phosphorus content, pH and altitude, whereas liana diameter and basal area were associated with soil magnesium and slope. A total of eight species had a positive association with the habitat and a further six showed a negative association. Four species had a positive association with the flatland habitat, but only three and two species, respectively, with slope and valley habitats. The slope habitat gave the highest number of species that showed a negative association.

Conclusions: Liana diversity and structure varied between habitats. Some liana species showed different associations with specific habitats. Environmental variables were identified that influence liana diversity, structure and habitat associations. The study provides important information about the factors influencing liana success, and these will be of value in liana conservation and management in tropical forests.     

Molecular Epidemiology of Nontuberculous Mycobacteria Isolates from Clinical and Environmental Sources of a Metropolitan City

Introduction

While NTM infection is mainly acquired from environmental exposure, monitoring of environmental niches for NTM is not a routine practice. This study aimed to find the prevalence of environmental NTM in soil and water in four highly populated suburbs of Tehran, Iran.

Material and Methods

A total of 4014 samples from soil and water resources were collected and studied. Sediments of each treated sample were cultured in Lowenstein-Jensen medium and observed twice per week for growth rate, colony morphology, and pigmentation. Colonies were studied with phenotypic tests. Molecular analysis was performed on single colonies derived from subculture of original isolates. Environmental samples were compared with 34 NTM isolates from patients who were residents of the study locations.

Results

Out of 4014 samples, mycobacteria were isolated from 862 (21.4%) specimens; 536 (62.1%) belonged to slow growing mycobacteria (SGM) and 326 (37.8%) were rapid growing mycobacteria (RGM). The five most frequent NTM were M. farcinogens (105/862; 12.1%), M. fortuitum (72/862; 8.3%), M. senegalense (58/862; 6.7%), M. kansasii (54/862; 6.2%), and M. simiae (46/862; 5.3%). In total, 62.5% (539/862) of mycobacterial positive samples were isolated from water and only 37.4% (323/862) of them were isolated from soil samples (P<0.05). Out of 5314 positive clinical samples for mycobacteria, 175 (3.2%) isolates were NTM. The trend of NTM isolates increased from 1.2% (13 out of 1078) in 2004 to 3.8% (39 out of 1005) in 2014 (P = 0.0001). The major clinical isolates were M. simiae (51; 29.1%), M. kansasii (26; 14.8%), M. chelonae (28; 16%), and M. fortuitum (13; 7.4%).

Conclusions

Comparing the distribution pattern of environmental NTM isolates with clinical isolates suggests a possible transmission link, but this does not apply to all environmental NTM species. Our study confirms an increasing trend of NTM isolation from clinical samples that needs further investigation.     

High cell density provides potent survival signals for resting T-cells.

Activated T-cells are susceptible to apoptosis through two particularly important pathways: ligation of CD95 (Fas/Apo-1) or cytokine deprivation. Resting T-cells have until recently been considered to be relatively resistant to apoptosis. In this report we show that resting T-cells die rapidly by apoptosis when deprived of serum or cell contact. Primed CD45RO+ cells were more susceptible than naive CD45RA+ cells, consistent with their relative expression of Bcl-2. CD4+, CD8+ and gammadelta T-cells were equally prone to apoptosis under all studied conditions. A linear relationship between cell survival and serum concentration was observed for cells cultured between 0.5-2x10(6)/ml. T-cells cultured at low density died even in high concentrations of serum. However, resting T-cells cultured at high cell density (4x10(6)/ml) survived for extended periods in the absence of serum or other survival factors. This effect was mediated by the production of soluble factors and independent of integrin mediated signals. These results suggest that T-cells at sites of high density such as the lymph node paracortex are independent of external survival factors, while those trafficking through the peripheral circulation are highly dependent on serum derived factors for survival.     

A review on fisheries and conservation status of Asian horseshoe crabs

Horseshoe crabs are the only extant xiphosurans and are believed to be morphologically unchanged for more than 200 million years. Of the four extant species namely, Limulus polyphemus, Tachypleus tridentatus, Tapinauchenius gigas and Carcinoscorpius rotundicauda, the latter three are found in Asian waters. Recent evidences showed that Asian horseshoe crabs are facing serious threats such as degradation of their spawning grounds and habitat, environmental pollution, overexploitation as a culinary delicacy and biomedical bleeding practices. Baseline data on the distribution and existing population of the wild horseshoe crabs remain poorly known in several Asian regions. Several studies have clearly revealed that pressure due to over-fishing of wild stock has increased tremendously in the last decade. Due to an increase in demand for Tachypleus Amebocyte Lysate (TAL) analogous to Limulus Amebocyte Lysate (LAL) in the United States, there is an urgent need to comprehensively address their fishing and conservation measures in the Asian region. This review addresses the overall studies on three species of Asian horseshoe crabs in relation to their fishing practices, local exploitation of their wild stock either for human consumption (or) by biomedical industries. The authors have structured the discussion on an international scale to address the existing problems in fishing and conservation of horseshoe crabs. Since no specific regulatory force or legislative protection act or a policy to preserve their natural stock are available to this date, this paper strongly recommends representative countries to include horseshoe crabs under their wildlife protection act to avoid further unsustainable exploitation of their wild populations.     

基于生态位模型的艾比湖国家级自然保护区马鹿生境评价

生境评价和预测是对濒危物种进行有效保护的基础。通过2013年9月和2014年10月对新疆艾比湖国家级自然保护区开展2次秋季野外调查共收集了92处马鹿(Cervuselaphus)出现数据,利用马鹿出现数据作为分布点数据,选取地形、植被类型和气候因子3类23种因子作为生境变量,利用MAXENT生态位模型分析了新疆艾比湖国家级自然保护区马鹿秋季生境适宜性分布特征和主要生境因子对马鹿分布的影响。结果表明:模型预测结果较高,平均AUC(area under the curve,受试工作者曲线下面值)值为0.976;Jackknife检验结果显示:最热月最高温度对马鹿生境分布的影响较大。植被类型和坡度对马鹿生境分布的影响不大。海拔、年降雨量、气温日较差和最热季平均温度是影响马鹿生境分布的主要生境因子。马鹿秋季生境划分为高适宜、次适宜、低适宜和不适宜4个等级,马鹿的高适宜生境区主要分布在研究区域的北部,次适宜及低适宜生境区则分布于高适宜生境区的边缘,而不适宜生境区主要集中在西部和东部地区。研究不仅提供了马鹿在艾比湖的实际分布状况,也为马鹿生境和生境因子的关系方面提供了一个重要的科学依据。     

Design and synthesis of new fused carbazole-imidazole derivatives as anti-diabetic agents: In vitro α-glucosidase inhibition,kinetic, and in silico studies

Twenty three fused carbazole–imidazoles 6a–w were designed, synthesized, and screened as new α-glucosidase inhibitors. All the synthesized fused carbazole-imidazoles 6a-w were found to be more active than acarbose (IC₅₀?=?750.0?±?1.5?µM) against yeast α-glucosidase with IC₅₀ values in the range of 74.0?±?0.7–298.3?±?0.9?µM. Kinetic study of the most potent compound 6v demonstrated that this compound is a competitive inhibitor for α-glucosidase (K_i value?=?75?µM). Furthermore, the in silico studies of the most potent compounds 6v and 6o confirmed that these compounds interacted with the key residues in the active site of α-glucosidase.     

Patterns of liana community diversity and structure in a tropical rainforest reserve,Ghana: effects of human disturbance

Most studies have concluded that liana diversity and structure increase with disturbance. However, a contradictory pattern has emerged recently calling for more research in the area. Liana diversity and structure were investigated in three forest types that differ in disturbance intensity (nondisturbed, moderately disturbed and heavily disturbed forest: NDF, MDF and HDF, respectively) in the Atewa Range Forest Reserve, Ghana. In each forest type, 10 square plots of 0.25 ha were demarcated. Lianas with diameter ≥1 cm located on trees with diameter ≥10 cm were enumerated. A total of 429 individuals representing 40 species, 29 genera and seventeen families were identified in the study. Shannon diversity and species richness of lianas were significantly lower in the HDF (P < 0.05). Liana density and basal area differed significantly across all forest types (P < 0.0001). The importance value index (IVI) of most liana species varied greatly across the forest types. The current study has provided evidence to support the pattern of decreasing liana diversity and structure with disturbance in some tropical forests. Further studies are recommended to gain more understanding of the factors that are responsible for the divergent liana responses to disturbance in tropical forests.