Atypical Mitogen-Activated Protein Kinase Phosphatase Implicated in Regulating Transition from Pre-S-Phase Asexual Intraerythrocytic Development of Plasmodium falciparum

Intraerythrocytic development of the human malaria parasite Plasmodium falciparum appears as a continuous flow through growth and proliferation. To develop a greater understanding of the critical regulatory events, we utilized piggyBac insertional mutagenesis to randomly disrupt genes. Screening a collection of piggyBac mutants for slow growth, we isolated the attenuated parasite C9, which carried a single insertion disrupting the open reading frame (ORF) of PF3D7_1305500. This gene encodes a protein structurally similar to a mitogen-activated protein kinase (MAPK) phosphatase, except for two notable characteristics that alter the signature motif of the dual-specificity phosphatase domain, suggesting that it may be a low-activity phosphatase or pseudophosphatase. C9 parasites demonstrated a significantly lower growth rate with delayed entry into the S/M phase of the cell cycle, which follows the stage of maximum PF3D7_1305500 expression in intact parasites. Genetic complementation with the full-length PF3D7_1305500 rescued the wild-type phenotype of C9, validating the importance of the putative protein phosphatase PF3D7_1305500 as a regulator of pre-S-phase cell cycle progression in P. falciparum.     

IVIg Treatment Reduces Catalytic Antibody Titers of Renal Transplanted Patients

Catalytic antibodies are immunoglobulins endowed with enzymatic activity. Catalytic IgG has been reported in several human autoimmune and inflammatory diseases. In particular, low levels of catalytic IgG have been proposed as a prognostic marker for chronic allograft rejection in patients undergoing kidney transplant. Kidney allograft is a treatment of choice for patients with end-stage renal failure. Intravenous immunoglobulins, a therapeutic pool of human IgG, is used in patients with donor-specific antibodies, alone or in conjunction with other immunosuppressive treatments, to desensitize the patients and prevent the development of acute graft rejection. Here, we followed for a period of 24 months the levels of catalytic IgG towards the synthetic peptide Pro-Phe-Arg-methylcoumarinimide in a large cohort of patients undergoing kidney transplantation. Twenty-four percent of the patients received IVIg at the time of transplantation. Our results demonstrate a marked reduction in levels of catalytic antibodies in all patients three months following kidney transplant. The decrease was significantly pronounced in patients receiving adjunct IVIg therapy. The results suggests that prevention of acute graft rejection using intravenous immunoglobulins induces a transient reduction in the levels of catalytic IgG, thus potentially jeopardizing the use of levels of catalytic antibodies as a prognosis marker for chronic allograft nephropathy.     

Chemical Composition of Ethanolic Extracts from some Seaweed Species of the South Indian Coastal Zone,their Antibacterial and Membrane-Stabilizing Activity

Russian Journal of Marine Biology - The present study was intended to investigate the presence of major chemical components in seaweed extracts by using of Fourier-transform infrared spectroscopy...     

Neural responses in human superior temporal cortex support coding of voice representations

The ability to recognize abstract features of voice during auditory perception is an intricate feat of human audition. For the listener, this occurs in near-automatic fashion to seamlessly extract complex cues from a highly variable auditory signal. Voice perception depends on specialized regions of auditory cortex, including superior temporal gyrus (STG) and superior temporal sulcus (STS). However, the nature of voice encoding at the cortical level remains poorly understood. We leverage intracerebral recordings across human auditory cortex during presentation of voice and nonvoice acoustic stimuli to examine voice encoding at the cortical level in 8 patient-participants undergoing epilepsy surgery evaluation. We show that voice selectivity increases along the auditory hierarchy from supratemporal plane (STP) to the STG and STS. Results show accurate decoding of vocalizations from human auditory cortical activity even in the complete absence of linguistic content. These findings show an early, less-selective temporal window of neural activity in the STG and STS followed by a sustained, strongly voice-selective window. Encoding models demonstrate divergence in the encoding of acoustic features along the auditory hierarchy, wherein STG/STS responses are best explained by voice category and acoustics, as opposed to acoustic features of voice stimuli alone. This is in contrast to neural activity recorded from STP, in which responses were accounted for by acoustic features. These findings support a model of voice perception that engages categorical encoding mechanisms within STG and STS to facilitate feature extraction.

Voice perception occurs via specialized networks in higher order auditory cortex, but how voice features are encoded remains a central unanswered question. Using human intracerebral recordings of auditory cortex, this study provides evidence for categorical encoding of voice.     

Leaf architecture characters of <i>Vachellia tortilis</i> (Forssk.) Galasso and Banfi along longitudinal gradient in Limpopo Province,South Africa

This paper looked at the leaf architecture characteristics of Vachellia tortilis to determine if either there is or not an effect of the tropic line on plants. Vachellia tortilis leaves were sampled along a national road (N1) in Limpopo province. Sampling points were set 10 km apart away from the Tropic of Capricon in opposite directions. Leaf morphology revealed that leaves of V. tortilis are bipinnately compound with alternate arrangement. The venation pattern of the pinnules was eucamptodromus and brochidodromous with imperfect reticulation. Areoles were imperfect and pentagonal or irregular in shape.