%) 63.2 ± 0.4 63.1 ± 0.4 Er (at.%) 1.7 ± 0.4 1.9 ± 0.4 Er (at·cm−3) 1.1 × 1021 1.3 × 1021 Si excess (at.%) Approximately 3.6 % Approximately 3.5% Figure 3 shows the 3D distributions of Si, O, and Er atoms within the reconstructed volume obtained from the APT analysis of the as-deposited layer where each dot Temsirolimus datasheet corresponds to one atom detected. Statistical treatment of APT data was used to quantify concentration fluctuations in the sample. Frequency distribution was compared to binomial distribution to evidence the phase separation and atom

clustering. This treatment performed on as-deposited material indicates a homogeneous spatial distribution of the three chemical species (Si, O, and Er) in the analyzed volume (41 × 41 × 88 nm3). Thus, it suggests that no Er clustering occurs during the deposition process. Moreover, learn more it is worth to note that, based on these frequency distributions, we estimate that Si-ncs or Er clusters with a diameter below 0.8 nm (corresponding to agglomerated 15 Si atoms or 10 Er atoms) could not be distinguished from free Si or Er atoms. These atomic scale investigations, correlated with the PL data (Figure 1), suggest that in the as-deposited sample, the Si sensitizers consist of less than 15 Si atoms and are check details efficient to excite neighboring Er3+ ions. Figure 3 3D reconstruction of the as-grown Er-doped SRSO layers of APT analysis. APT reconstruction of 3D distribution of silicon,

oxygen, and erbium atoms in the as-grown sample. The volume analyzed is 41×41×88 nm3 . Before 2003 [13], the standard annealing treatment, applied for the formation of Si-NCs in Si-rich SiO2 materials fabricated by different approaches, was an annealing at 1,100°C for 1 h in pure nitrogen gas. The same annealing treatment was

considered to be efficient to create the Si-NCs in Er-doped Si-rich SiO2 materials to achieve a sensitizing effect towards rare-earth ions. Figure 4 shows the 3D cluster-filtered distribution of chemical species in the Er-SRSO layers submitted to such thermal treatment. The Si-ncs are clearly seen; their density is estimated to be about (3.1 ± 0.2)×1018Si-ncs/cm3. triclocarban The mean distance between Si-ncs, derived from their density, is found to be 6.9±0.2 nm, which is in agreement with that deduced from the 3D reconstruction. The Si-ncs are spherical in shape and are homogeneously distributed in the analyzed volume. Simultaneously, a large density of Er-rich clusters approximately (2.0×1018Er-NCs/cm3) has also been detected in the sample (Figure 4). Furthermore, some Si-ncs are interconnected by Er clusters (or channel) as illustrated in the inset of Figure 4. No particular morphology of these Er clusters has been deduced. Figure 4 3D reconstruction of the annealed Er-doped SRSO layers of APT analysis. 3D cluster-filtered distributions of chemical species (Si in red and Er in blue) in Er-doped SRSO layers annealed at 1,100°C for 1 h. For clarity, only silicon and erbium atoms which belong to clusters are represented.

However, strain ABU 83972 is able to outcompete CFT073 strain in urine [51]. The results presented herein indicate that both strains undergo an oxidative stress during the exponential growth.

Nonetheless, ABU 83972 strain displays more active antioxidant defenses which led to a significant decrease in ROS level in stationary phase. Our results agree with the gene expression profiling in strains ABU 83972 and CFT073 in urine, which showed that sodA, encoding superoxide dismutase and ahpC, encoding hydroperoxide reductase are significantly up-regulated [49, 52]. Interestingly the highest expression values were obtained in ABU 83972 selleck chemical strain [49]. To further explore the oxidative response, other studies will be performed to examine the contribution of each factor involved in this response and the importance of metabolic changes in these isolates. The UPEC strains CFT073

(urosepsis/pyelonephritis isolate), 536 (pyelonephritis, B2 subgroup III) and UTI89 (cystitis, B2 subgroup IX) [25] are very well adapted for growth in the human urinary tract and present similar antioxidant defense systems. However, a clear distinction can be drawn between them. Strains CFT073 and 536 behave similarly with respect Emricasan datasheet to ROS formation in exponential phase in contrast to UTI89 (p = 0.016). The metabolic fluxes could be distributed differently in UTI89, which may decrease the endogenous production Florfenicol of ROS. The more efficient antioxidant metabolism related to greater exposure to endogenous oxidative stress

may be responsible for the difference in lifestyle between ABU 83972 and CFT073 strains. ABU 83972 strain exploits urine more efficiently than UPEC strains [11]. Previous study has shown that a more active antioxidant defense system increases the capacity to colonize the bladder [53]. Thus, a high level of antioxidant defenses associated to fast growth in the urine (this work), low abundance of fimbriae, and possible biofilm formation [54] could explain why ABU83972 strain is able to establish a long-term bacteriuria. Additionally, ROS are implicated in DNA mutagenesis which may be adaptive as reported in biofilm for antibiotic-resistance [55], or more generally, during starvation [56]. The high levels of ROS in ABU strain 83972 may explain the genetic alterations described [27]. Conclusions We showed that growth in human urine of many E. coli strains belonging to different phylogenetic groups and pathovars was associated with an endogenous oxidative stress. The growth of ABU strain 83972 was associated with a high level of ROS and more active antioxidant defenses. The increased level of ROS may be responsible for adaptive mutations. A more active antioxidant defense system could increase the capacity to colonize the bladder. Acknowledgements We thank Bioquanta for PD-1 inhibitor making the Mitoxis platform available. CA was supported by an INSERM fellowship.

However, in a study of the distribution of CSE1L in selleck products cancer cells, we observed that in addition to granule-like staining in cytoplasm surrounding the perinuclear areas, CSE1L also showed vesicle-like staining in the protrusions of MCF-7 cells in immunofluorescence [63]. Cytoplasmic

vesicles play important CYT387 roles in regulating the exocytosis and secretion of cells [64]. The vesicle-like staining of CSE1L in cell protrusions indicates that CSE1L may play a role in regulating cell secretion. The protrusions of cancer cells also play a role in facilitating cancer cell invasion [65]. Furthermore, increased CSE1L expression was shown to increase the secretion of HT-29 cells [66]. These results suggest that CSE1L may regulate the secretion and

invasion of cancer cells. Extracellular matrix (ECM) surrounding tumor and ECM-degrading proteases secreted by tumor cells play crucial roles in modulating cancer metastasis [67–69]. Matrix metalloproteinases (MMPs), including MMP-2, are enzymes involved in the degradation of ECM, which show increased expression during cancer metastasis [70–76]. MMP-2 production can be regulated at the level of secretion [77]. Metastatic tumor cells often INCB28060 develop enhanced secretory abilities in order to enhance MMPs secretion, thereby enhancing their metastatic potential [78]. Double-staining immunofluorescence showed that CSE1L regulates the translocation and secretion of MMP-2-containing vesicles [11]. Matrigel-based invasion assays showed that enhanced

CSE1L expression increased cell invasion, and reduced CSE1L expression inhibited the invasion of MCF-7 cancer cells [11]. Finally, animal tumor metastasis experiments showed that reduced CSE1L expression decreased the pulmonary metastasis of B16-F10 cells, pheromone a highly metastatic cancer cell line, in C57BL/6 mice [11, 79]. Therefore, CSE1L regulates MMP-2 secretion and enhances the invasion of cancer cells. CSE1L is a secretory protein and there is a higher prevalence of secretory CSE1L in sera of patients with metastatic cancer CSE1L is highly expressed in cancer, and its expression level is well correlated with advanced cancer stage and worse patient outcomes. Therefore, CSE1L may play an important role in cancer progression. CSE1L is a microtubule-associated protein [4]. Our recent study showed that the association of CSE1L with microtubules is related with protrusion extension and migration of MCF-7 breast cancer cells [80]. In the immunofluorescence study, CSE1L was colocalized with MMP-2 in vesicles surrounding the outside of the MCF-7 cell membranes [Fig 1; also see [63]]. Since MMP-2 is a secretory protein, these results suggest that CSE1L may be secreted together with MMP-2.

Once taken up by ChuA and transported across the outer membrane, heme is internalized into the periplasm and then bound by heme-specific periplasmic transport protein ChuT, which mediates heme transfer to the cytoplasm through an ATP-binding cassette (ABC) transporter [10]. The indirect strategy for iron acquisition is based on a shuttle mechanism, which uses small-molecule compounds called siderophores as high-affinity ferric iron chelators [11], including the catecholates enterobactin, salmochelin, the hydroxamate aerobactin, and yersiniabactin [12]. Salmochelin molecules were

first discovered in Salmonella enterica[13]. The iroA locus responsible for salmochelin production was also first identified in Salmonella spp. [14]. Salmochelins

are C-glucosylated derivatives www.selleckchem.com/Caspase.html of enterobactin, encoded by the iroBCDEN gene cluster [15]. Among E. coli isolates, iro sequences have been described in ExPEC strains isolated from patients with neonatal meningitis [16], UTIs, and prostatitis in humans https://www.selleckchem.com/HDAC.html [17, 18], as well as from APEC isolates from poultry. Compared to enterobactins, salmochelins are superior siderophores in the presence of serum albumin, which may suggest that salmochelins are considerably more important in the pathogenesis of certain E. coli and Salmonella infections than enterobactins [19]. In ExPEC strains, the gene cluster responsible for salmochelin biosynthesis and transport is generally found on ColV or ColBM virulence plasmids, and has also been identified on chromosomal pathogenicity-associated islands (PAI) in some strains [20]. The salmochelin gene cluster contains a gene encoding a cytoplasmic esterase, IroD. IroD can hydrolyze the ester bonds of both enterobactin and salmochelin molecules, which is required for subsequent iron release from salmochelin [21, 22]. Aerobactin is a hydroxamate siderophore

produced by most APEC strains and other pathogenic E. coli. It is synthesized by the iucABCD-encoded gene products and taken up by the iutA-encoded receptor protein [23–25]. Despite the chemical diglyceride differences among these distinct siderophores, each system is comprised of components mediating the specific steps required for ferric iron uptake, including siderophore synthesis in the cytoplasm, secretion, reception of the ferri-siderophore at the outer membrane surface, Pitavastatin internalization, and iron release in the cytoplasm [26]. While both APEC and UPEC strains have multiple iron acquisition systems, the role of distinct iron uptake systems in the pathogenesis of both APEC and UPEC has not been illustrated in the same chicken challenge model. In this study, the genes chuT, iroD and iucD were chosen to assert the roles of heme, salmochelin and aerobactin in the virulence of APEC E058 and UPEC U17.

PCR was conducted with TaKaRa Ex Taq HS DNA polymerase in 50 μl reaction volumes. Primers (synthesized by Sangon Technology, Shanghai, China) used were including GAPDH (sense, 5′-ACGGATTTGGTCGTATTGGGCG-3′; antisense, 5′-CTCCTGGAAGATGGTGATGG-3′) with a product length of 197 bp and CD133 (sense, 5′-TTACGGCACTCTTCACCT-3′; antisense, 5′-TATTCCACAAGCAGCAAA-3′) with a product length of 172 bp. The reactions were conducted for GAPDH as the internal control under the following conditions: initial denaturing

step at 95°C for 1 min, 28 cycles of 95°C for 1 min, 55°C for 1 min, 72°C for 1 min, followed by 72°C for 10 min; For CD133: initial denaturing step at 94°C for 2 min, 28 cycles at 94°C for 30 seconds, 51°C for 30 seconds, 72°C for 30 seconds, followed by 72°C for 10 min. according to the manufacturer’s instruction Five μl CD133 PCR and 2 μl of the products amplified by MyCycler™ Thermal Cycler (Bio-Red Laboratories, CA, USA) Selleck GDC 973 were separated on a 1.5% agarose gel (Gene Tech, Shanghai, China) by electrophoresis apparatus (Tunon, EpS 100, Shanghai Tian-neng Tech Co. Shanghai, China). Digital images to exposure the occurrence of CD133 mRNA as a white target strip were captured on a gel documentation system (UNIVERSAL HOOD II, Bio-Red Laboratories, Segrate, Milan, Italy). Imaging assessments

to measure the brightness scale value (BSV) of CD133 automatically from the write strip and to compared the relative ratio between CD133 strip and control strip were carried out by Quantity One 1-D analysis software (The Discoveries™ Quantity One Idasanutlin 1-D Analysis Software Version 4.5, Bio-Red Laboratories, CA, USA.). Clinicopathological

assessments Clinicopathological parameters included gender, age, tumor size histological grade, invasion depth, lymph node metastasis, TNM stage, lymphatic vessel infiltration, vascular infiltration and metastatic lymph node ratio for CD133 protein and CD133 mRNA assessments respectively [13, 15], mainly according to UICC Cell press classification [15]. And Ki-67 LI was also used in the evaluation of CD133 mRNA expression. Prognostic analysis The deadline of follow-up for 99 Nirogacestat purchase patients was until November 2009, and the average survival time was 26.76 ± 17.02 months. A total of 9 cases (9.1% patients) lost in follow-up period. In this registered group, 39 cases died of the recurrence of gastric cancer, vascular diseases of brain or heart, or complications after surgery respectively. All patients in this group for survival assessment were divided as positive or negative subgroup of CD133 immunostaining. Statistics All statistical analyses were performed with the SPSS software version 13.0 (SPSS, Chicago, IL, USA). The correlations between expression of CD133 protein and clinicopathological parameters were assessed with the chi-squared test as a univariate analysis.

5 MPa, while empty circles present those in normal conditions. Figure 7 Comparison of dynamic viscosity of MgAl 2 O 4 -DG

nanofluids in normal conditions [[60]] and under a pressure of 7.5 MPa. The increase in viscosity of the material subjected to anisotropic pressure of 7.5 MPa was in the range from 10.04% to 22.04% for the 10% mass concentration of the nanoparticles in suspension. The suspension of 20 wt.% concentration of nanoparticles increase in dynamic viscosity from 6.19% to 19.54% in the tested range of shear rates. The test results AZD1152 mouse clearly show that pressure affects on the dynamic viscosity of examined nanofluids, causes it to rise, but does not change the nature of the viscosity curve. ICG-001 manufacturer The effect of maximum of viscosity curve ubiquitin-Proteasome degradation for some shear rate could be seen and described in [60]. This demonstrates that this effect does not depend on the measurement method, or the nature of the measuring geometry used. Electrorheology A study on the impact of the applied electric field on the dynamic viscosity of MgAl2O4-DG nanofluids was performed. Experiments

were conducted in the electric field intensity from 0 to 2,000 V/mm using the same measurement process used to study the material viscosity curves under normal conditions presented in [60]. The experimental results are summarized in Figure 8; various colors indicate the results for each value of the electric field, and the different types of points correspond to different mass concentrations of nanoparticles in nanosuspension. Figure 8 Comparison of dynamic viscosity of MgAl 2 O 4 -DG nanofluids at various intensities of electric field in temperature (22.5±1.5)° not C. Different types of points correspond to different mass concentrations of nanoparticles in nanofluid; colors indicate different intensities of electric field. Reasons for differences between the results of measurements of dynamic viscosity of nanofluids in the same mass concentration

of nanoparticles at various values of the electric field should be sought in imperfection of measurement system, in which it is impossible to make measurements at constant temperature. As previously described, an air-cooled system can work only in room temperature; a cooling system is effective at temperatures higher than 40°C. In the Laboratory of Biophysics at Rzeszów University of Technology, measurements were conducted in an operational air conditioning system, but in spite of this, there is a fluctuation in air temperature. The measurement data were collected in temperatures ranging from 21°C to 24°C. Based on this information, it can be assumed that the electric field does not affect the dynamic viscosity of the test material in the test range of electric field.

The annual list from the CDC now includes exotic strain types not previously recognized. From 2007 data, the CDC estimates that Salmonella species account for approximately 20% of

suspected outbreaks and greater than 3500 illnesses find more among the sentinel states (http://​www.​cdc.​gov/​mmwr/​preview/​mmwrhtml/​mm5931a1.​htm?​s_​cid=​mm5931a1_​w). Although S. Senftenberg is not listed among the top 20 serotypes implicated in human illness [4] the organism is routinely detected in humans and has been recognized in clinical non-human cases of disease (ranked #10 in 2006) and in non-clinical non-human cases (ranked #4), supporting NVP-BEZ235 molecular weight the potential for the emergence of this strain type in human disease. An important aspect in the characterization of pathogens is an assessment of the role of molecular analysis in determining clonal and strain distribution across various environments and hosts. While there are a range of methods available for strain characterization and sub-typing, the most commonly used methods include Pulse Field Gel Electrophoresis (PFGE) [5–8], Multi-Locus Sequence Type (MLST) analysis [6, 9, 10],

and virulence or resistance gene carriage [11–13]. In addition, phenotypical analysis includes trait expression through antimicrobial susceptibility analysis or phenotype microarray type analysis [1, 14, 15]. PFGE has become a powerful tool in assessing the genetic relatedness of SIS3 in vitro strains and is commonly used by the CDC, USDA and other federal agencies for assessing strains implicated in both human and animal disease www.selleck.co.jp/products/Adrucil(Fluorouracil).html and outbreaks associated with a particular pathogen. The method involves selective restriction of the genome and analysis

of fragment patterns using a pulsed electric field. Restriction patterns generated are compared to controls strains and each other using cluster analysis software [6, 16]. While PFGE offers great power in comparative analysis and is relatively useful for visual representation of strain differences, it can suffer limitations. Not all strains may restrict well or will not restrict with specified enzymes and the time required for preparation and analysis can be intensive [17, 18]. Others have reported that PFGE may have limited discriminatory power in subtyping certain highly clonal serotypes such as S. Enteriditis and S. Hadar [19] and may require multiple enzymes to be of benefit [20]. Multi-Locus Sequence Type (MLST) analysis is also useful as a tool in molecular analysis – it uses the approach of allelic differences in the sequence of various house-keeping genes which can be exploited to differentiate strains [6, 21, 22].

Briefly, mice were lightly anesthetized by intraperitoneal (i.p.) injection of a 200 μl mixture consisting of selleck compound Ketamine (12 mg/ml Anaket-V, Centaur Labs) and Xylazine (1.6 mg/ml, Rompun, Bayer). Mice were gently lifted by the loose skin at the throat, and kept upright with its head tilted back and the nose pointed up. Using a pipette with a sterile

tip, 40 μl of the declumped mycobacterial suspension was applied to the nostrils. Animals were maintained upright for another 30 seconds to ensure complete delivery to the buy GW2580 respiratory system. Six weeks (day 42) later, mice were infected under light anaesthesia intragastrically (i.g.) with 200–250 (low dose) or 500–600 (high dose) embryonated T. muris eggs or an equal volume of PBS. At

Nec-1s supplier week 9 (day 63), mice were culled and the relevant organs removed for investigation. The second protocol (Figure 1B) was designed to first establish a TH2-inducing T. muris infection prior to challenge with M. bovis BCG infection. Animals were infected i.g. with 200–250 embryonated T. muris eggs or an equal amount of PBS on day 1 and every 10 days thereafter until experimental completion. On day 10, animals were infected i.n. with 1–5 × 105 CFU BCG bacilli or an equal volume of PBS. After 6 weeks (day 52), all mice were humanely euthanized and the relevant organs removed for investigation. Experiments were completed in triplicate at three separate times. Figure 1 Experimental design. (A) BALB/c mice were infected i.n. with M. bovis BCG on day 1, followed by i.g. T. muris infection on day 42. Mice were killed on day 63 and the relevant tissues collected for further analysis.

(B) BALB/c mice were infected i.g. with T. muris every 10 days starting on day 1. Animals were co-infected i.n. with M. bovis BCG on day 10. Mice were killed on day 52 and the relevant tissues collected. Appropriate single infections and PBS controls were included in parallel for both protocols. Experiments were performed with 5 to 10 animals per group. P values <0.05 were considered statistically significant. (ns = non significant). Immune phenotyping and intracellular cytokine analysis Immune phenotyping was performed using single cell suspensions from spleens and mesenteric lymph nodes (MLNs). Intracellular cytokine expression was determined following Endonuclease stimulation with 50 ng/ml Phorbol 12-myristate 13-acetate (PMA) (Sigma), 1 μg/ml Ionomycin (Sigma) and 10 μg/ml Brefeldin A (BFA) (Sigma) for 4 hours at 37°C and 5% CO2. Cells were resuspended in PBS containing 1% BSA and 0.1% Sodium Azide (wash buffer) and stained for 30 minutes with fluorochrome conjugated anti-mouse antibodies against CD3, CD4, CD8, CD25, B220, Foxp3, IFN-γ and IL-4 (BD Biosciences, Caltag or Biolegend). Cells were fixed with 1% formaldehyde, washed and resuspended in wash buffer. Lymphocyte populations were determined based on their Forward/Side scatter profile and gates set with the help of appropriate FMOs and Isotype controls.

Even though a variety

of cytokines are induced upon Giardia-host cell interaction, there is no strong intestinal inflammatory response exerted. Nevertheless, a role of T cells in elimination of Giardia infection has been shown by Singer and Nash in mice [31]. A specific T cell proliferative response to Giardia proteins in humans has been reported [32] and it has been suggested that ADI can inhibit this response [33]. Indeed, we could show that the secreted Giardia protein ADI is capable of reducing the human PBMC proliferative response after T cell specific stimulation (Figure 6) and thereby probably inhibit a strong immune response in vivo. Maximum effects Poziotinib supplier were gained with a concentration of 5 μg/mL GiADI or above. This amount of GiADI is reasonable for mimicking the in vivo situation, since Giardia produces and releases ADI constantly. This finding is also in accordance with the decreased see more click here proliferation shown for T cells cultured without L-arginine

[34] that was shown to be due to down-regulation of the CD3zeta chain of the T cell receptor. Furthermore, we were able to completely revert the observed reduction in T cell specific stimulated PBMC proliferation by addition of arginine to physiological levels (Figure 6). Arginine is part of certain oral rehydration formulations used for treating diarrhea. However, adverse reactions such as osmotic diarrhea and excessive liver urea production [35, 36] are not in favor of such a therapy. In addition, arginine supplementation therapy might also be beneficial for the growth of Giardia itself, selleck products since the parasite uses arginine as an energy source. For these reasons we also tested the arginine-metabolite citrulline as an alternative supplementary therapy within this study. Citrulline can be reverted into arginine by argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL), which were both expressed in the IECs used for this study, but not in Giardia. It is not clear up to now if citrulline can also be reconverted into arginine in vivo by human cells such as IECs, dendritic cells and T cells.

However, in children up to 3 years the arginine-reconverting enzymes ASS and ASL are actively expressed in IECs [37]. In addition, ASS and ASL were detected in the canine intestine [38] and it was shown that citrulline supplementation leads to increased arginine levels also in IECs in adult mice [39]. Thus it is likely, that citrulline conversion into arginine is possible in the intestine of human adults. In accordance to this, we could show that citrulline is capable of reversing all the described arginine-dependent effects on NO-production and T cell proliferation that Giardia is exerting (Figures 3d and Figure 6). Interestingly, the arginine-dependent block of proliferation that was shown to be induced in IECs upon Giardia infection, could also be reverted by citrulline [7].

Scientific names adopted here are those accepted by the latest Kew World Checklist of Selected Plant Families accessed via the web. All the herbarium specimens collected and studied were kept in the Herbarium of the Biology Department at the Faculty of Science, Universiti Putra Malaysia (UPM). Specimens in herbaria locally and abroad were also studied, especially those at the Singapore Botanical Garden (SING), the Royal Botanic Gardens Kew Herbarium (K), University Malaya (KLU), FRIM (KEP), and Universiti Kebangsaan Malaysia (UKMB) for further verification. Results and discussion A total of eighty five orchid species from 61 genera were collected during the period of study, of which 52 are epiphytic

p53 activator or lithophytic and thirty three are terrestrial. Seven species were identified as new records for the Penang selleck Hill. The seven species are Bulbophyllum biflorum, Coelogyne septemcostata, Cymbidium haematodes, Dendrobium convexa, Lepidogyne longifolia, Liparis barbata and Thrixspermum duplocallosum. B. biflorum was previously recorded only from Pahang and Selangor by Turner (1995) but currently is known to be selleck products widespread

within Malaysia. C. septemcostata and L. longifolia was previously only recorded as lowland forest species in Pahang and Johore. C. haematodes, however, was only known from Pulau Langkawi. D. convexa was previously found in Pontian, Johore and Ulu Kali, Selangor. L. barbata was previously documented in Perak, Tioman Island and Johore. Besides the new records, there were also some species collected which are common

to Penang but not to Peninsular Malaysia, except for certain localities, such as Acriopsis indica, Campanulorchis leiophylla and Hetaeria oblongifolia. Eria, Dendrobium Demeclocycline and Bulbophyllum were among the genera with the most species found in this study site. The Western Hill exhibited a high diversity of orchid as the highest number of orchids was recorded from the Western Hill Trail. This correlates with the elevation of the land as the Western Hill is the highest peak in the Penang Hill system. The higher elevation provides a suitable environment for the orchids to thrive as the temperature is lower and the humidity is higher. The Moniot Road East, Moniot Road West, Government Hill Trail and Cendana Hill Trail were also among the selected trails where more than six species were collected. The other trails visited, however, exhibited a lower diversity. This might be due to the rapid development of the town and some recreational areas which affected orchid growth. Most of the orchid specimens collected are epiphytic and lithophytic. There were also several terrestrials. This is because of the limited soils or humus to support plant growth as there are numerous huge granite borders and outcrops in this area. Hence, most of the orchids are growing abundantly on tree trunks and rocks layered with plant sediments or humus.