Observation on a 65-kilodalton protein isolated from kanagawa positive strains of Vibrio parahaemolyticus

Crude hemolysin from four KP+ strains of Vibrio parahaemolyticus belonging to serotype 02:K3 exhibited a major protein band (molecular weight, 65 kilodaltons (kDa] in addition to a previously known thermostable direct hemolysin band (molecular weight, 21 kDa) in SDS - polyacrylamide slab gel electrophoresis. These strains showed maximum virulence leading to 100% mouse lethality within 2-6 h. It is hypothesized that this 65-kDa protein may play a vital role in the pathogenesis of the disease caused by V. parahaemolyticus.     

Nature and properties of humic acid prepared from different sources and its effect on nutrient availability

Summary Effect of sources, moisture levels and extractants on extraction, analytical properties, IR-spectra, macromolecular characteristics, interaction with cations and physiological properties of the extracted material (humic acid) were studied. Among the three variables, extractant influenced the degree of humification, IR-spectra, nature and properties of humic acids to a greater extent though the other two had significant contribution. Sodium pyrophosphate found to be an ideal extractant for humic acid. Reduced viscosity of humic acids increased with dilution particularly below 0.1 g/dl and decreased with increasing H⁺ concentration between pH 6.5 and 8.5 irrespective of source, moisture level and extractant. The amount of proton released and drop in initial pH of humic acids on addition of different metal ions indicated formation of mono-, di-hydroxy metal-HA complexes which broke down at pH 8.0 and above. HA-Fe²⁺ and HA-Cu²⁺ complexes were found to be most stable. Humic acids from different sources varied significantly in their effect on available nutrient status of soils though, the latter is main determining factor particularly for calcium and magnesium.     

Orai1 and STIM reconstitute store-operated calcium channel function

The two membrane proteins, STIM1 and Orai1, have each been shown to be essential for the activation of store-operated channels (SOC). Yet, how these proteins functionally interact is not known. Here, we reveal that STIM1 and Orai1 expressed together reconstitute functional SOCs. Expressed alone, Orai1 strongly reduces store-operated Ca(2+) entry (SOCE) in human embryonic kidney 293 cells and the Ca(2+) release-activated Ca(2+) current (I(CRAC)) in rat basophilic leukemia cells. However, expressed along with the store-sensing STIM1 protein, Orai1 causes a massive increase in SOCE, enhancing the rate of Ca(2+)entry by up to 103-fold. This entry is entirely store-dependent since the same coexpression causes no measurable store-independent Ca(2+) entry. The entry is completely blocked by the SOC blocker, 2-aminoethoxydiphenylborate. Orai1 and STIM1 coexpression also caused a large gain in CRAC channel function in rat basophilic leukemia cells. The close STIM1 homologue, STIM2, inhibited SOCE when expressed alone but coexpressed with Orai1 caused substantial constitutive (store-independent) Ca(2+) entry. STIM proteins are known to mediate Ca(2+) store-sensing and endoplasmic reticulum-plasma membrane coupling with no intrinsic channel properties. Our results revealing a powerful gain in SOC function dependent on the presence of both Orai1 and STIM1 strongly suggest that Orai1 contributes the PM channel component responsible for Ca(2+) entry. The suppression of SOC function by Orai1 overexpression likely reflects a required stoichiometry between STIM1 and Orai1.     

Induction of endothelial apoptosis by 4-hydroxyhexenal.

Lipid peroxidation and its products such as 4-hydroxy-2-nonenal (HNE) and 4-hydroxyhexenal (HHE) are known to affect redox balance during aging and various degenerative processes, including vascular dysfunction. Deterioration of the endothelial cells that line the vascular wall is known to be an underlying cause of vascular dysfunction. At present, little is known about the mechanism by which HHE induces endothelial cell death (i.e. apoptosis), although HNE-induced apoptotic cell death has been reported. The aim of this study was to determine whether apoptosis induced by HHE in endothelial cells involves peroxynitrite (ONOO(-)). Our results show that in endothelial cells HHE triggers apoptotic cell death by inducing apoptotic Bax coupled with a decrease in anti-apoptotic Bcl-2. Results show that HHE induces reactive oxygen species (ROS), nitric oxide, and ONOO(-) generation, leading to redox imbalance. Furthermore, the antioxidant N-acetyl cysteine, ROS scavenger, and penicillamine, an ONOO(-) scavenger, were found to block HHE-mediated apoptosis. We used confocal laser microscopy to estimate the ability of these inhibitors to attenuate HHE-induced intracellular ONOO(-) levels thus confirming the oxidative mediation of apoptosis in endothelial cells. These findings strongly suggest that accumulated HHE triggers reactive species-mediated endothelial apoptosis, leading to vascular dysfunction as well as vascular aging. During aging, increased lipid peroxidation and its associated production of HHE may exacerbate the weakened redox balance, leading to various chronic degenerative processes including vascular dysfunction.     

Synthesis and evaluation of Triticum durum — T. monococcum amphiploids

Summary Nine Triticum durum — T. monococcum amphiploids (AABBA^mA^m) were synthesized by chromosome doubling of sterile triploid F₁ hybrids involving nine T. durum (AABB) cultivars and a T. monococcum (A^mA^m) line. The triploid F₁ hybrids had a range of 4–7 bivalents and 7–13 univalents per PMC. The synthetic amphiploids, however, showed a high degree of preferential pairing of chromosomes of the A genomes of diploid and tetraploid wheats. The amphiploids were meiotically stable and fully fertile. Superiority of four amphiploids for tiller number per plant, 100-grain weight, protein content and resistance to Karnal bunt demonstrated that these could either be commercially exploited as such after overcoming certain inherent defects or used to introgress desirable genes into durum and bread wheat cultivars. Methods for improvement of these amphiploids are discussed.     

Melatonin rhythms in the pineal and non-pineal tissues and their physiological implications in subtropical fish

Abstract

Melatonin (N-acetyl-5-methoxy tryptamine), following discovery from the extracts of bovine pineal gland, has been detected in the pineal as well as several extra-pineal tissues/organs of different vertebrates including fish. The unique feature of melatonin in the pineal gland is its rhythmic biosynthesis and release in blood in synchronization with the environmental light-–dark cycle. Accordingly, melatonin produced in the pineal of an animal living in a changing environment is implicated to the regulation of seasonal reproduction by acting as a hormone at one or more levels of hypothalamo-hypophyseal-gonadal axis. Additionally, melatonin is known to act as a potent free-radical scavenger or antioxidant to influence maturation of oocytes. However, possible relationship between extra-pineal melatonin and seasonality of reproduction in any animal remains enigmatic. Perhaps, carp is the only known animal in which temporal patterns of melatonin levels in the serum as well as in the extracts of pineal, retina, ovary, gut, and liver have been studied in relation to the reproductive events in an annual cycle. The purpose of current review is to bring those fascinating, and arguably most important data together to underline their significance in the control of seasonal reproduction in subtropical fish in general and in carp in particular.     

Improved Culture Media for Embryogenic Callus Generation in Sorghum [<i>Sorghum bicolor</i> (L.) Moench]

Many attempts on optimization of sorghum [Sorghum bicolor (L.) Moench] tissue culture induction media have been made, but the culture system remains with some bottlenecks compared to that of other crops. This study aimed at assessing the suitability of various induction media to produce embryogenic callus (yellow and friable) with high induction rates and reduced phenolic exudation. The six culture medium modifications: 3 based on Murashige and Skoog (MS) medium and one each based on Chu N6, Gamborg B5 and 190-2 media respectively were applied in the culture of mature embryos from 10 sorghum genotypes. Although there was a genotype influence on the attainment of a yellow callus, friability of the callus was determined to be dependent on the culture medium and not the genotype. Half strength MS medium with 0.2 mg/l 2,4-D with 2.8 g/l Gelrite® as the gelling agent modified with 1.0 g/l KH₂PO₄, 1.0 g/l L-proline, 1.0 g/l L-asparagine and 0.16 mg/l CuSO₄·5H₂O (type E) was found to be the most effective resulting in about 60% yellow coloured callus induction with 25% friability. Addition of CuSO₄·5H₂O, KH₂PO₄, L-proline and L-asparagine significantly reduced the phenolic production. Half strength MS medium was observed to contribute to quality callus production when compared to full strength MS media modified with the compounds. The half strength MS medium was also observed to suppress phenolic production. Medium 190-2 produced the highest regeneration frequency (40%) among the 3-regeneration media tested. The results provide information on a suitable sorghum callus induction medium necessary for embryogenesis.