Reproductive biology,length-weight relationship and diet of co-occurring butterfly rays,Gymnura poecilura and Gymnura zonura,in Malaysian waters

Recent IUCN assessments had resulted in up listing of the status of butterfly rays due to concerns of overfishing, but inadequate biological understanding of these rays prevents meaningful conservation and management measures. Therefore, this study was undertaken to address knowledge gaps in the reproductive biology and diet of longtail butterfly ray (Gymnura poecilura) and zone tail butterfly ray (Gymnura zonura) in Malaysian waters. From surveys of landing sites and fish markets from years 2017 to 2022, size (disc width, DW), weight and maturity were recorded, and stomachs were collected from 94 G. poecilura (N = 39 females and 55 males) and 20 G. zonura (N = 10 females and 10 males) specimens. The length-weight relationships were significantly different between sexes for G. poecilura. The size at maturity (DW50) was estimated to be 476.0 mm (females), 385.0 mm (males) for G. poecilura and 442.0 mm (combined) for G. zonura. The number of embryos ranged from 1 to 6, and the embryo size was between 73.90 to 130.44 mm DW. Dietary analysis of stomach contents revealed that fish prey was dominant in both G. poecilura [94.4% Index of Relative Importance (IRI)] and G. zonura (100% IRI). Ontogenetic shift was seen in G. poecilura that fed on more variety of prey items, including shrimps, squids and crabs with an increase in body size. Both species co-occur all along coastal Malaysia although G. zonura is rarely encountered from fisheries surveys along the Strait of Malacca. Given similar habitat associations and dietary habits, G. poecilura may be able to outcompete G. zonura across their shared habitat range. The validity of G. japonica and G. micrura records in Malaysia remains questionable and requires future investigation.     

Production of aposporous gametophytes and calli from Pteris vittata L. pinnae strips cultured in vitro

Murashige and Skoog's modified medium in 1% Difco Bacto-agar supplemented with sugar alcohols (sorbsitol, mannitol), growth regulators (1-naphthalenacetic acid, 2,4-dichlorophenoxyacetic acid, benzyladenine, kinetin) and sugars (fructose, glucose, sucrose) induced aposporous gametophytes from pinnae of Pteris vittata cultured in vitro at lower concentrations of all the mentioned components. Aposporous gametophytes and vegetative calli were produced at higher concentrations. The calli regenerated sporophytes when cultured on MS medium without growth regulators. The gametophytes grew vegetatively on MS medium but produced sporophytes when transferred into 0.1 strength MS medium. This is the first report of simultaneous production of calli and gametophytes from fern explants.     

Expression and function of asialo GM1 in alloreactive cytotoxic T lymphocytes

In the present study we examined asialo GM1 (AsGM1) expression and its function in alloreactive cytotoxic T lymphocytes (CTL). We consistently found that the cytotoxic activity of bulk culture-derived allo-CTL was susceptible to the treatment of anti-AsGM1 (alpha AsGM1) plus complement. To further determine whether the expression of AsGM1 was maintained in CTL, we examined cloned T cells. The expression of AsGM1 in the T cell clones was assessed by their susceptibility to lysis by alpha AsGM1 plus complement and the reduction or abrogation of their cytotoxic activity by this treatment. It was found that, with one exception, all Lyt-2+, Thy-1+ CTL clones were AsGM1+ (seven out of eight), independent of their class specificity (class I or class II). In contrast, all Thy-1+, L3T4+ CTL (2) or helper T cell (4) clones AsGM1-. These findings suggested that there was a close association between the expression of AsGM1 and the expression of Lyt-2. The cytotoxic reaction of the anti-class I MHC CTL clones that expressed AsGM1 was blocked by alpha AsGM1 or alpha Lyt-2 antibody. The Lyt-2+, AsGM1+ anti-class II MHC CTL clone-mediated lysis was inhibited by alpha AsGM1. Addition of AsGM1 in micelle form (AsGM1-M) alone also blocked the cytotoxic reactions. Addition of other structurally similar but antigenically different glycolipids or other non-AsGM1-containing liposome preparations did not affect CTL-mediated cytotoxicity. Furthermore, adding both alpha AsGM1 and AsGM1-M together at proper doses inhibited the blocking effect (deblocking) of either alone, and other structurally similar glycolipids did not inhibit the blocking. The deblocking was specific, since AsGM1-M did not affect the blocking by alpha Lyt-2. These findings indicate that not only is AsGM1 expressed in a majority of Lyt-2+ CTL clones, but it may also be involved in the CTL- target interaction to mediate lytic reaction.     

Aspartic acid 50 and tyrosine 108 are essential for receptor binding and cytotoxic activity of tumour necrosis factor beta (lymphotoxin).

Single amino acid substitutions were generated in predicted hydrophilic loop regions of the human tumour necrosis factor beta (TNF-beta) molecule, and the mutant proteins were expressed in Escherichia coli and purified. Mutants with single amino acid changes at either of two distinct loop regions, at positions aspartic acid 50 or tyrosine 108, were found to have greatly reduced receptor binding and cytotoxic activity. These two regions in TNF-beta correspond to known loop regions where mutations also result in loss of biological activity of TNF-alpha, a related cytokine which shares the same cellular receptors with TNF-beta. The two distinct loops at positions 31-34 and 84-89 in the known three-dimensional structure of TNF-alpha (equivalent to positions 46-50 and 105-110 respectively in TNF-beta), lie on opposite sides of the TNF-alpha monomer. When the TNF-alpha monomer forms a trimer, the two loops, each from a different subunit of the trimer, come together and lie in a cleft between adjacent subunits. Together, these findings suggest that a TNF receptor binds to a cleft between subunits via surface loops at amino acid residues 31-34 and 84-89 in TNF-alpha, and similarly via surface loops including amino acids aspartic acid 50 and tyrosine 108 in TNF-beta.     

Pro-opiocortin processing in the pituitary: A model for neuropeptide biosynthesis

The biosynthesis of α-MSH, β-endorphin and ACTH in the pituitary is reviewed. These neuropeptides are synthesized from a common pro-protein, pro-opiomelanocortin. The pro-protein is cleaved intragranularly, at pairs of basic residues in the molecule to yield the respective peptide products. An unique, thiol protease (pro-opiocortin converting enzyme) and a carboxypeptidase B-like enzyme, both localized within pituitary secretory granules and having a pH optimum of 5–6, appear to be involved in the proteolytic processing of pro-opiomelanocortin.     

A parallel algorithm for robust fault detection in semiconductor manufacturing processes

The semiconductor manufacturing consists of a number of processes, and even a small fault occurring at any point can damage the product quality. The fast and accurate detection of such faults is essential to maintain high manufacturing yields. In this paper, we propose a parallel algorithm for fault detection in semiconductor manufacturing processes. The algorithm is a modification of the discord detection algorithm called HOT SAX, which adopted the SAX representation of time-series for efficient storage and computation. We first propose a sequential algorithm and then extend it to a parallel version. We evaluate our algorithm through experiments using the data obtained from a real-world semiconductor plasma etching process. As a result, our fault detection algorithm achieved 100 % accuracy without any false positive or false negative.     

Insertion state of modular protein nanopores into a membrane

In the past decade, significant progress has been made in the development of new protein nanopores. Despite these advancements, there is a pressing need for the creation of nanopores equipped with relatively large functional groups for the sampling of biomolecular events on their extramembranous side. Here, we designed, produced, and analyzed protein nanopores encompassing a robust truncation of a monomeric β-barrel membrane protein. An exogenous stably folded protein was anchored within the aqueous phase via a flexible peptide tether of varying length. We have extensively examined the pore-forming properties of these modular protein nanopores using protein engineering and single-molecule electrophysiology. This study revealed distinctions in the nanopore conductance and current fluctuations that arose from tethering the exogenous protein to either the N terminus or the C terminus. Remarkably, these nanopores insert into a planar lipid membrane with one specific conductance among a set of three substate conductance values. Moreover, we demonstrate that the occurrence probabilities of these insertion substates depend on the length of the peptide tether, the orientation of the exogenous protein with respect to the nanopore opening, and the molecular mass of tethered protein. In addition, the three conductance values remain unaltered by major changes in the composition of modular nanopores. The outcomes of this work serve as a platform for further developments in areas of protein engineering of transmembrane pores and biosensor technology.