The excitatory neurotransmitter glutamate is involved in the control of most, perhaps all, neuroendocrine systems, yet the sites of glutamatergic neurons and their processes are unknown. Here, we used in situ hybridization and immunohistochemistry for the neuron-specific vesicular glutamate transporter-2 (VGLUT2) to identify the neurons in female rats that synthesize the neurotransmitter glutamate as well as their projections throughout the septum-hypothalamus. The results show that glutamatergic neurons are present in the septum-diagonal band complex and throughout the hypothalamus. The preoptic area and ventromedial and dorsomedial nuclei are particularly rich in glutamatergic neurons, followed by the supraoptic, paraventricular, and arcuate nuclei, whereas the suprachiasmatic nucleus does not express detectable amounts of VGLUT2 mRNA. Immunoreactive neurites are seen in very high densities in all regions analyzed, particularly in the preoptic region, followed by the ventromedial, dorsomedial, and arcuate nuclei as well as the external layer of the median eminence, whereas the mammillary complex does not exhibit VGLUT2 immunoreactivity. Many VGLUT2 immunoreactive fibers also contained synaptophysin, suggesting that the transporter is indeed localized to presynaptic terminals. Together, the results identify glutamatergic cell bodies throughout the septum-hypothalamus in region-specific patterns and show that glutamatergic nerve terminals are present in very large numbers such that most neurons in these brain regions can receive glutamatergic input. We examined the GnRH system as an example of a typical neuroendocrine system and could show that the GnRH perikarya are closely apposed by many VGLUT2-immunoreactive boutons, some of which also contained synaptophysin. The presence of VGLUT2 mRNA-containing cells in specific nuclei of the hypothalamus indicates that many neuroendocrine neurons coexpress glutamate as neurotransmitter, in addition to neuropeptides. These systems include the oxytocin, vasopressin, or CRH neurons as well as many others in the periventricular and mediobasal hypothalamus. The presence of VGLUT2 mRNA in steroid-sensitive regions of the hypothalamus, such as the anteroventral periventricular, paraventricular, or ventromedial nuclei indicates that gonadal and adrenal steroid can directly alter the functions of these glutamatergic neurons.

Cultivation of Escherichia coli on wheat-bran substrate under various Solid-State Fermentation (SSF) conditions was evaluated for phytase yield along with the enzyme activity profile as a potential, low-cost alternative to submerged-liquid fermentation. The maximum phytase activity achieved by E. coli was 350 ± 50 SPU of phytase activity per gram of bran, incubated for 96 h with a substrate bed moisture content of 70% (w/v) at 37 °C with a relative air humidity of 90%, and supplemented with 10% (w/w bran) Luria-Bertani broth powder which translates into a 300% increase in phytase activity compared with an un-supplemented culture. The greatest improvements in phytase yield were associated with nutrient supplementation and the optimization of initial substrate moisture content. E. coli production of phytase utilizing solid-state fermentation technology was shown to be feasible utilizing the low-cost agro-residue wheat bran as substrate. Furthermore, the effect of pH and temperature on phytase activity was monitored from pH 2.5 to pH 7.5, and for temperatures ranging from 20 °C to 70 °C. Optimal phytase activity was at pH 5.5 and 50 °C when produced under the SSF optimized conditions.

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