Proteome analysis of schizophrenia patients Wernicke's area reveals an energy metabolism dysregulation

Background: Schizophrenia is likely to be a consequence of DNA alterations that, together with environmental factors, will lead to protein expression differences and the ultimate establishment of the illness. The superior temporal gyrus is implicated in schizophrenia and executes functions such as the processing of speech, language skills and sound processing. Methods: We performed an individual comparative proteome analysis using two-dimensional gel electrophoresis of 9 schizophrenia and 6 healthy control patients' left posterior superior temporal gyrus (Wernicke's area - BA22p) identifying by mass spectrometry several protein expression alterations that could be related to the disease. Results: Our analysis revealed 11 downregulated and 14 upregulated proteins, most of them related to energy metabolism. Whereas many of the identified proteins have been previously implicated in schizophrenia, such as fructose-bisphosphate aldolase C, creatine kinase and neuron-specific enolase, new putative disease markers were also identified such as dihydrolipoyl dehydrogenase, tropomyosin 3, breast cancer metastasis-suppressor 1, heterogeneous nuclear ribonucleoproteins C1/C2 and phosphate carrier protein, mitochondrial precursor. Besides, the differential expression of peroxiredoxin 6 (PRDX6) and glial fibrillary acidic protein (GFAP) were confirmed by western blot in schizophrenia prefrontal cortex. Conclusion: Our data supports a dysregulation of energy metabolism in schizophrenia as well as suggests new markers that may contribute to a better understanding of this complex disease.

Genetic Background of Patients from a University Medical Center in Manhattan: Implications for Personalized Medicine

Background: The rapid progress currently being made in genomic science has created interest in potential clinical applications; however, formal translational research has been limited thus far. Studies of population genetics have demonstrated substantial variation in allele frequencies and haplotype structure at loci of medical relevance and the genetic background of patient cohorts may often be complex. Methods and Findings: To describe the heterogeneity in an unselected clinical sample we used the Affymetrix 6.0 gene array chip to genotype self-identified European Americans (N = 326), African Americans (N = 324) and Hispanics (N = 327) from the medical practice of Mount Sinai Medical Center in Manhattan, NY. Additional data from US minority groups and Brazil were used for external comparison. Substantial variation in ancestral origin was observed for both African Americans and Hispanics; data from the latter group overlapped with both Mexican Americans and Brazilians in the external data sets. A pooled analysis of the African Americans and Hispanics from NY demonstrated a broad continuum of ancestral origin making classification by race/ethnicity uninformative. Selected loci harboring variants associated with medical traits and drug response confirmed substantial within-and between-group heterogeneity. Conclusion: As a consequence of these complementary levels of heterogeneity group labels offered no guidance at the individual level. These findings demonstrate the complexity involved in clinical translation of the results from genome-wide association studies and suggest that in the genomic era conventional racial/ethnic labels are of little value.

Mast cell repopulation of the peritoneal cavity: contribution of mast cell progenitors versus bone marrow derived committed mast cell precursors

Background: Mast cells have recently gained new importance as immunoregulatory cells that are involved in numerous pathological processes. One result of these processes is an increase in mast cell numbers at peripheral sites. This study was undertaken to determine the mast cell response in the peritoneal cavity and bone marrow during repopulation of the peritoneal cavity in rats. Results: Two mast cell specific antibodies, mAb AA4 and mAb BGD6, were used to distinguish the committed mast cell precursor from more mature mast cells. The peritoneal cavity was depleted of mast cells using distilled water. Twelve hours after distilled water injection, very immature mast cells could be isolated from the blood and by 48 hours were present in the peritoneal cavity. At this same time the percentage of mast cells in mitosis increased fourfold. Mast cell depletion of the peritoneal cavity also reduced the total number of mast cells in the bone marrow, but increased the number of mast cell committed precursors. Conclusions: In response to mast cell depletion of the peritoneal cavity, a mast cell progenitor is released into the circulation and participates in repopulation of the peritoneal cavity, while the committed mast cell precursor is retained in the bone marrow.

Vascular relaxation of canine visceral arteries after ischemia by means of supraceliac aortic cross-clamping followed by reperfusion

Background: The supraceliac aortic cross-clamping can be an option to save patients with hipovolemic shock due to abdominal trauma. However, this maneuver is associated with ischemia/reperfusion (I/R) injury strongly related to oxidative stress and reduction of nitric oxide bioavailability. Moreover, several studies demonstrated impairment in relaxation after I/R, but the time course of I/R necessary to induce vascular dysfunction is still controversial. We investigated whether 60 minutes of ischemia followed by 30 minutes of reperfusion do not change the relaxation of visceral arteries nor the plasma and renal levels of malondialdehyde (MDA) and nitrite plus nitrate (NOx). Methods: Male mongrel dogs (n = 27) were randomly allocated in one of the three groups: sham (no clamping, n = 9), ischemia (supraceliac aortic cross-clamping for 60 minutes, n = 9), and I/R (60 minutes of ischemia followed by reperfusion for 30 minutes, n = 9). Relaxation of visceral arteries (celiac trunk, renal and superior mesenteric arteries) was studied in organ chambers. MDA and NOx concentrations were determined using a commercially available kit and an ozone-based chemiluminescence assay, respectively. Results: Both acetylcholine and calcium ionophore caused relaxation in endothelium-intact rings and no statistical differences were observed among the three groups. Sodium nitroprusside promoted relaxation in endothelium-denuded rings, and there were no inter-group statistical differences. Both plasma and renal concentrations of MDA and NOx showed no significant difference among the groups. Conclusion: Supraceliac aortic cross-clamping for 60 minutes alone and followed by 30 minutes of reperfusion did not impair relaxation of canine visceral arteries nor evoke biochemical alterations in plasma or renal tissue.

Videodensitometric analysis of advanced carotid plaque: correlation with MMP-9 and TIMP-1 expression

Background: Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of MMP (TIMP) promote derangement of the extracellular matrix, which is ultimately reflected in plaque images seen on ultrasound. Videodensitometry can identify structural disturbances in plaques. Objectives: To establish the correlations between values determined using videodensitometry in B-mode ultrasound images of advanced carotid plaques and the total expression of MMP-9 and TIMP-1 in these removed plaques. Methods: Thirty patients underwent ultrasonic tissue characterization of carotid plaques before surgery, using mean gray level (MGL), energy, entropy and homogeneity. Each patient was assigned preoperatively to one of 2 groups: group I, symptomatic patients (n = 16; 12 males; mean age 66.7 +/- 6.8 years), and group II, asymptomatic patients (n = 14; 8 males; mean age 67.6 +/- 6.81 years). Tissue specimens were analyzed for MMP-9 and TIMP-1 expression. Nine carotid arteries were used as normal tissue controls. Results: MMP-9 expression levels were elevated in group II and in normal tissues compared to group I (p < 0.001). TIMP-1 levels were higher in group II than in group I, and significantly higher in normal tissues than in group I (p = 0.039). The MGL was higher in group II compared to group I (p = 0.038). Energy had greater values in group II compared to group I (p = 0.02). There were no differences between patient groups in homogeneity and entropy. Energy positively correlated with MMP-9 and TIMP-1 expression (p = 0.012 and p = 0.031 respectively). Homogeneity positively correlated with MMP-9 and TIMP-1 expression (p = 0.034 and p = 0.047 respectively). There were no correlations between protein expression and MGL or entropy. Conclusions: Videodensitometric computer analysis of ultrasound scanning images can be used to identify stable carotid plaques, which have higher total expression levels of MMP-9 and TIMP-1 than unstable plaques.

Ultra-Deep Sequencing Reveals the microRNA Expression Pattern of the Human Stomach

Background: While microRNAs (miRNAs) play important roles in tissue differentiation and in maintaining basal physiology, little is known about the miRNA expression levels in stomach tissue. Alterations in the miRNA profile can lead to cell deregulation, which can induce neoplasia. Methodology/Principal Findings: A small RNA library of stomach tissue was sequenced using high-throughput SOLiD sequencing technology. We obtained 261,274 quality reads with perfect matches to the human miRnome, and 42% of known miRNAs were identified. Digital Gene Expression profiling (DGE) was performed based on read abundance and showed that fifteen miRNAs were highly expressed in gastric tissue. Subsequently, the expression of these miRNAs was validated in 10 healthy individuals by RT-PCR showed a significant correlation of 83.97% (P<0.05). Six miRNAs showed a low variable pattern of expression (miR-29b, miR-29c, miR-19b, miR-31, miR-148a, miR-451) and could be considered part of the expression pattern of the healthy gastric tissue. Conclusions/Significance: This study aimed to validate normal miRNA profiles of human gastric tissue to establish a reference profile for healthy individuals. Determining the regulatory processes acting in the stomach will be important in the fight against gastric cancer, which is the second-leading cause of cancer mortality worldwide.

A simplified minimal residual disease polymerase chain reaction method at early treatment points can stratify children with acute lymphoblastic leukemia into good and poor outcome groups

Background Minimal residual disease is an important independent prognostic factor in childhood acute lymphoblastic leukemia. The classical detection methods such as multiparameter flow cytometry and real-time quantitative polymerase chain reaction analysis are expensive, time-consuming and complex, and require considerable technical expertise. Design and Methods We analyzed 229 consecutive children with acute lymphoblastic leukemia treated according to the GBTLI-99 protocol at three different Brazilian centers. Minimal residual disease was analyzed in bone marrow samples at diagnosis and on days 14 and 28 by conventional homo/heteroduplex polymerase chain reaction using a simplified approach with consensus primers for IG and TCR gene rearrangements. Results At least one marker was detected by polymerase chain reaction in 96.4%, of the patients. By combining the minimal residual disease results obtained on days 14 and 28, three different prognostic groups were identified: minimal residual disease negative on days 14 and 28, positive on day 14/negative on day 28, and positive on both. Five-year event-free survival rates were 85%, 75.6%,, and 27.8%, respectively (p<0.0001). The same pattern of stratification held true for the group of intensively treated children. When analyzed in other subgroups of patients such as those at standard and high risk at diagnosis, those with positive B-derived CD10, patients positive for the TEL/AML1 transcript, and patients in morphological remission on a day 28 marrow, the event-free survival rate was found to be significantly lower in patients with positive minimal residual disease on day 28. Multivariate analysis demonstrated that the detection of minimal residual disease on day 28 is the most significant prognostic factor. Conclusions This simplified strategy for detection of minimal residual disease was feasible, reproducible, cheaper and simpler when compared with other methods, and allowed powerful discrimination between children with acute lymphoblastic leukemia with a good and poor outcome.

Evaluation of the Bond Strength Between a Composite Resin and Enamel Submitted to Bleaching Treatment and Etched with Er:YAG Laser

Background: The use of laser irradiation for dental surface treatment may increase tooth-composite bond strength. Its use on bleached teeth may decrease the waiting time between bleaching and restorative procedures. Objective: This study aimed to evaluate the bond strength between a composite resin and bovine enamel bleached with 35% hydrogen peroxide and etched with Er:YAG laser. Materials and Methods: Thirty bovine teeth were randomly divided into six groups (n = 5): G1, unbleached and restored 24 h after storage in artificial saliva, etching with 35% phosphoric acid (PA) (control); G2, unbleached and restored 24 h after storage in artificial saliva, etching with Er:YAG laser and 35% PA; G3, bleached and restored immediately afterward, etching with 35% PA; G4, bleached and restored 24 h after bleaching, etching with 35% PA; G5, bleached and restored immediately afterward, etching with Er:YAG and 35% PA laser; G6, bleached and restored 24 h after bleaching, etching with Er:YAG laser and 35% PA. Bond strength was quantitatively evaluated by microtensile test (1.0 mm/min). Data were submitted to statistical analysis using ANOVA and Tukey tests (alpha - 0.05). Results: Bond strength values (MPa) were G1, 26.17 +/- 4.44; G2, 28.87 +/- 3.94; G3, 17.25 +/- 4.58; G4, 21.93 +/- 5.02; G5, 16.69 +/- 2.31; and G6, 29.06 +/- 8.31. There was no statistically significant difference among groups G1, G2, and G6 (p - 0.119), which presented higher bond strength than group G4, followed by groups G3 and G5. Conclusion: Er:YAG irradiation of bleached surfaces may favor bonding procedures when performed 24 h after bleaching.

Effect of a Single Application of TiF(4) and NaF Varnishes and Solutions Combined with Nd:YAG Laser Irradiation on Enamel Erosion in Vitro

Objective: This in vitro study aimed to analyze the influence of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on the efficacy of titanium tetrafluoride (TiF(4)) and sodium fluoride (NaF) varnishes and solutions to protect enamel against erosion. Background data: The effect of Nd:YAG laser irradiation on NaF and AmF was analyzed; however, there is no available data on the interaction between Nd:YAG laser irradiation and TiF(4). Methods: Bovine enamel specimens were pre-treated with NaF varnish, TiF(4) varnish, NaF solution, TiF(4) solution, placebo varnish, Nd:YAG (84.9 J/cm(2)), Nd:YAG prior to or through NaF varnish, Nd:YAG prior to or through TiF(4) varnish, Nd:YAG prior to or through NaF solution, Nd:YAG prior to or through TiF(4) solution, and Nd:YAG prior to or through placebo varnish. Controls remained untreated. Ten specimens in each group were then subjected to an erosive demineralization (Sprite Zero, 4x90 s/day) and remineralization (artificial saliva, between the erosive cycles) cycling for 5 days. Enamel loss was measured profilometrically (mu m). Additionally, treated but non-eroded specimens were additionally analyzed by scanning electron microscope (SEM) (each group n-2). The data were statistically analyzed by ANOVA and Tukey's post-hoc test (p < 0.05). Results: Only TiF(4) varnish (1.8 +/- 0.6 mu m), laser prior to TiF(4) varnish (1.7 +/- 0.3 mu m) and laser prior to TiF(4) solution (1.4 +/- 0.3 mu m) significantly reduced enamel erosion compared to the control (4.1 +/- 0.6 mu m). SEM pictures showed that specimens treated with TiF(4) varnish presented a surface coating. Conclusions: Nd:YAG laser irradiation was not effective against enamel erosion and it did not have any influence on the efficacy of F, except for TiF(4) solution. On the other hand, TiF(4) varnish protected against enamel erosion, without the influence of laser irradiation.

Effects of Low-Level Laser Therapy and Orthodontic Tooth Movement on Dental Pulps in Rats

Objectives: To describe the microscopic pulpal reactions resulting from orthodontically induced tooth movement associated with low-level laser therapy (LLLT) in rats. Materials and Methods: Forty-five young male Wistar rats were randomly assigned to three groups. In group I (n = 20), the maxillary right first molars were submitted to orthodontic movement with placement of a coil spring. In group II (n = 20), the teeth were submitted to orthodontic movement plus LLLT at 4 seconds per point (buccal, palatal, and mesial) with a GaAlAs diode laser source (830 nm, 100 mW, 18 J/cm(2)). Group III (n = 5) served as a control (no orthodontic movement or LLLT). Groups I and 11 were divided into four subgroups according to the time elapsed between the start of tooth movement and sacrifice (12 hours, 24 hours, 3 days, and 7 days). Results: Up until the 3-day period, the specimens in group I presented a thicker odontoblastic layer, no cell-free zone of Weil, pulp core with differentiated mesenchymal and defense cells, and a high concentration of blood vessels. In group II, at the 12- and 24-hour time points, the odontoblastic layer was disorganized and the cell-free zone of Weil was absent, presenting undifferentiated cells, intensive vascularization with congested capillaries, and scarce defense cells in the cell-rich zone. In groups I and II, pulpal responses to the stimuli were more intense in the area underneath the region of application of the force or force/laser. Conclusions: The orthodontic-induced tooth movement and LLLT association showed reversible hyperemia as a tissue response to the stimulus. LLLT leads to a faster repair of the pulpal tissue due to orthodontic movement. (Angle Orthod. 2010;80:116-122.)

Placentation in Sigmodontinae: a rodent taxon native to South America

Background: Sigmodontinae, known as ""New World rats and mice,"" is a large subfamily of Cricetidae for which we herein provide the first comprehensive investigation of the placenta. Methods: Placentas of various gestational ages ranging from early pregnancy to near term were obtained for five genera, i.e. Necromys, Euryoryzomys, Cerradomys, Hylaeamys, and Oligoryzomys. They were investigated by means of histology, immunohistochemistry, a proliferation marker, DBA-lectin staining and transmission electron microscopy. Results: The chorioallantoic placenta was organized in a labyrinthine zone, spongy zone and decidua and an inverted yolk sac persisted until term. The chorioallantoic placenta was hemotrichorial. The interhemal barrier comprised fetal capillary endothelium and three layers of trophoblast, an outermost, cellular layer and two syncytial ones, with interspersed trophoblast giant cells (TGC). In addition, accumulations of TGC occurred below Reichert's membrane. The junctional zone contained syncytial trophoblast, proliferative cellular trophoblast, glycogen cells and TGC that were situated near to the maternal blood channels. In three of the genera, TGC were also accumulated in distinct areas at the placental periphery. PAS-positive glycogen cells derived from the junctional zone invaded the decidua. Abundant maternal uNK cells with positive response to PAS, vimentin and DBA-lectin were found in the decidua. The visceral yolk sac was completely inverted and villous. Conclusion: The general aspect of the fetal membranes in Sigmodontinae resembled that found in other cricetid rodents. Compared to murid rodents there were larger numbers of giant cells and in some genera these were seen to congregate at the periphery of the placental disk. Glycogen cells were found to invade the decidua but we did not identify trophoblast in the walls of the deeper decidual arteries. In contrast these vessels were surrounded by large numbers of uNK cells. This survey of wild-trapped specimens from five genera is a useful starting point for the study of placentation in an important subfamily of South American rodents. We note, however, that some of these rodents can be captive bred and recommend that future studies focus on the study of time dated pregnancies.

Chorioallantoic placentation in Galea spixii (Rodentia, Caviomorpha, Caviidae)

Background: Placentas of guinea pig-related rodents are appropriate animal models for human placentation because of their striking similarities to those of humans. To optimize the pool of potential models in this context, it is essential to identify the occurrence of characters in close relatives. Methods: In this study we first analyzed chorioallantoic placentation in the prea, Galea spixii, as one of the guinea pig's closest relatives. Material was collected from a breeding group at the University of Mossoro, Brazil, including 18 individuals covering an ontogenetic sequence from initial pregnancy to term. Placentas were investigated by means of histology, electron microscopy, immunohistochemistry (vimentin, alpha-smooth muscle actin, cytokeration) and proliferation activity (PCNA). Results: Placentation in Galea is primarily characterized by an apparent regionalization into labyrinth, trophospongium and subplacenta. It also has associated growing processes with clusters of proliferating trophoblast cells at the placental margin, internally directed projections and a second centre of proliferation in the labyrinth. Finally, the subplacenta, which is temporarily supplied in parallel by the maternal and fetal blood systems, served as the center of origin for trophoblast invasion. Conclusion: Placentation in Galea reveals major parallels to the guinea pig and other caviomorphs with respect to the regionalization of the placenta, the associated growing processes, as well as trophoblast invasion. A principal difference compared to the guinea pig occurred in the blood supply of the subplacenta. Characteristics of the invasion and expanding processes indicate that Galea may serve as an additional animal model that is much smaller than the guinea pig and where the subplacenta partly has access to both maternal and fetal blood systems.

A VLT/FLAMES survey for massive binaries in Westerlund 1 III. The WC9d binary W239 and implications for massive stellar evolution

Context. There is growing evidence that a treatment of binarity amongst OB stars is essential for a full theory of stellar evolution. However the binary properties of massive stars - frequency, mass ratio & orbital separation - are still poorly constrained. Aims. In order to address this shortcoming we have undertaken a multiepoch spectroscopic study of the stellar population of the young massive cluster Westerlund 1. In this paper we present an investigation into the nature of the dusty Wolf-Rayet star and candidate binary W239. Methods. To accomplish this we have utilised our spectroscopic data in conjunction with multi-year optical and near-IR photometric observations in order to search for binary signatures. Comparison of these data to synthetic non-LTE model atmosphere spectra were used to derive the fundamental properties of the WC9 primary. Results. We found W239 to have an orbital period of only similar to 5.05 days, making it one of the most compact WC binaries yet identified. Analysis of the long term near-IR lightcurve reveals a significant flare between 2004-6. We interpret this as evidence for a third massive stellar component in the system in a long period (> 6 yr), eccentric orbit, with dust production occuring at periastron leading to the flare. The presence of a near-IR excess characteristic of hot (similar to 1300 K) dust at every epoch is consistent with the expectation that the subset of persistent dust forming WC stars are short (< 1 yr) period binaries, although confirmation will require further observations. Non-LTE model atmosphere analysis of the spectrum reveals the physical properties of the WC9 component to be fully consistent with other Galactic examples. Conclusions. The simultaneous presence of both short period Wolf-Rayet binaries and cool hypergiants within Wd 1 provides compelling evidence for a bifurcation in the post-Main Sequence evolution of massive stars due to binarity. Short period O+OB binaries will evolve directly to the Wolf-Rayet phase, either due to an episode of binary mediated mass loss - likely via case A mass transfer or a contact configuration - or via chemically homogenous evolution. Conversely, long period binaries and single stars will instead undergo a red loop across the HR diagram via a cool hypergiant phase. Future analysis of the full spectroscopic dataset for Wd 1 will constrain the proportion of massive stars experiencing each pathway; hence quantifying the importance of binarity in massive stellar evolution up to and beyond supernova and the resultant production of relativistic remnants.

Expression of an activating mutation in the gene encoding the K(ATP) channel subunit Kir6.2 in mouse pancreatic beta cells recapitulates neonatal diabetes

Neonatal diabetes is a rare monogenic form of diabetes that usually presents within the first six months of life. It is commonly caused by gain-of-function mutations in the genes encoding the Kir6.2 and SUR1 subunits of the plasmalemmal ATP-sensitive K(+) (K(ATP)) channel. To better understand this disease, we generated a mouse expressing a Kir6.2 mutation (V59M) that causes neonatal diabetes in humans and we used Cre-lox technology to express the mutation specifically in pancreatic beta cells. These beta-V59M mice developed severe diabetes soon after birth, and by 5 weeks of age, blood glucose levels were markedly increased and insulin was undetectable. Islets isolated from beta-V59M mice secreted substantially less insulin and showed a smaller increase in intracellular calcium in response to glucose. This was due to a reduced sensitivity of K(ATP) channels in pancreatic beta cells to inhibition by ATP or glucose. In contrast, the sulfonylurea tolbutamide, a specific blocker of K(ATP) channels, closed K(ATP) channels, elevated intracellular calcium levels, and stimulated insulin release in beta-V59M beta cells, indicating that events downstream of K(ATP) channel closure remained intact. Expression of the V59M Kir6.2 mutation in pancreatic beta cells alone is thus sufficient to recapitulate the neonatal diabetes observed in humans. beta-V59M islets also displayed a reduced percentage of beta cells, abnormal morphology, lower insulin content, and decreased expression of Kir6.2, SUR1, and insulin mRNA. All these changes are expected to contribute to the diabetes of beta-V59M mice. Their cause requires further investigation.

Complete Genome Sequence of Mycoplasma suis and Insights into Its Biology and Adaption to an Erythrocyte Niche

Mycoplasma suis, the causative agent of porcine infectious anemia, has never been cultured in vitro and mechanisms by which it causes disease are poorly understood. Thus, the objective herein was to use whole genome sequencing and analysis of M. suis to define pathogenicity mechanisms and biochemical pathways. M. suis was harvested from the blood of an experimentally infected pig. Following DNA extraction and construction of a paired end library, whole-genome sequencing was performed using GS-FLX (454) and Titanium chemistry. Reads on paired-end constructs were assembled using GS De Novo Assembler and gaps closed by primer walking; assembly was validated by PFGE. Glimmer and Manatee Annotation Engine were used to predict and annotate protein-coding sequences (CDS). The M. suis genome consists of a single, 742,431 bp chromosome with low G+C content of 31.1%. A total of 844 CDS, 3 single copies, unlinked rRNA genes and 32 tRNAs were identified. Gene homologies and GC skew graph show that M. suis has a typical Mollicutes oriC. The predicted metabolic pathway is concise, showing evidence of adaptation to blood environment. M. suis is a glycolytic species, obtaining energy through sugars fermentation and ATP-synthase. The pentose-phosphate pathway, metabolism of cofactors and vitamins, pyruvate dehydrogenase and NAD(+) kinase are missing. Thus, ribose, NADH, NADPH and coenzyme A are possibly essential for its growth. M. suis can generate purines from hypoxanthine, which is secreted by RBCs, and cytidine nucleotides from uracil. Toxins orthologs were not identified. We suggest that M. suis may cause disease by scavenging and competing for host nutrients, leading to decreased life-span of RBCs. In summary, genome analysis shows that M. suis is dependent on host cell metabolism and this characteristic is likely to be linked to its pathogenicity. The prediction of essential nutrients will aid the development of in vitro cultivation systems.